Clinical evaluation of direct composite versus zirconia resin-bonded fixed dental prostheses for a single missing anterior tooth: A short-term multicenter retrospective study.

Despite differences in material strength, CR-RBFDPs without fiber reinforcement showed reliable short-term clinical results. This direct composite restoration has the advantage of being less invasive and can be restored in a single visit.


Cardamonin inhibits the expression of inflammatory mediators in TNF-α-stimulated human periodontal ligament cells.

We show that cardamonin reduces inflammatory mediator production by inhibiting the activation of several signaling pathways in this manuscript.


A dual composite resin injection molding technique with 3D-printed flexible indices for biomimetic replacement of a missing mandibular lateral incisor.

The bilayered direct composite RBFPD using 3D printed flexible indices prepared with a full digital workflow has several advantages over other dental prosthetic solutions, including noninvasiveness, cost-effectiveness, biomimetic esthetics, repairability, and shortened treatment times. Although the initial results are promising, further longitudinal studies with larger patient cohorts are required to confirm the long-term efficacy of this approach.


Comparative bonding performance of coronal dentin disks and CAD/CAM resin composite disks for biological restoration: The impact of resin-coating technique.

This study evaluated the bonding performance of coronal dentin disks, designed for biological restoration, and CAD/CAM resin composite disks when bonded to flat dentin surfaces using dual-cure resin cements, with and without a resin-coating (RC) technique. Three distinct groups were established within the non-RC group, each using one of the two types of resin cements in a self-adhesive mode: one-step self-etch adhesive (1-SEA) without light-cure, 1-SEA with light-cure, and a separate group using an alternate cement. Within the RC group, a subgroup was established for each cement. The microtensile bond strength (μTBS) of the disk-dentin beam was tested after 0 and 10,000 thermocycles in a 5°C/55°C. No significant μTBS difference was observed among the non-RC groups. However, when using RC, the μTBSs of coronal dentin disks significantly exceeded those of CAD/CAM resin composite disks. Thermocycle aging did not affect μTBS in any of the bonding methods, except in self-adhesive mode.


Cardamonin decreases inflammatory mediator expression in IL-1β-stimulated human periodontal ligament cells.

In this study, we found that cardamonin could suppress the production of inflammatory mediators in HPDLCs as well as the activation of several signaling pathways induced by IL-1β treatment.


International human resource development in Japanese dental field

歯学領域における国際的人材育成に関する調査

目的:歯学領域の国際的人材育成に関する情報収集を目的に本調査を実施した．
 方法:日本歯科医学教育学会発行の『歯科医学教育白書』(計5冊)の国際交流に関するデータ，および2022年に日本歯科医学会連合が実施した調査をもとに，わが国の歯学領域における国際的人材育成のあり方について検討した．
 結果:わが国の29歯科大学で学ぶ外国人留学生数は，287名(2009年)，325名(2012年)，514名(2014年)，766名(2017年)，988名(2021年)と経時的に増加し，学士あるいは博士の課程を修めるアジア諸国出身者がいずれの年も90%以上を占めていた．一方，日本人教員等は概ね2年以内の期間，客員研究員，教員として海外留学しており，その留学先の90%以上が欧米諸国であった．
 結論:この国際交流の相違点を踏まえ，各国の歯科保健医療状況の相互理解を進めていくことが，わが国の歯学領域における国際的人材の育成，延いては国際化推進に寄与すると考えられた．

Journal of Japanese Dental Science Federation


Effect of surface topography and wettability on shear bond strength of Y-TZP ceramic.

was essential for establishing a reliable resin-zirconia bond.

on the μSBS were analyzed by multiple linear regression analysis (p < 0.05). Multiple regression analysis revealed that the nSI% was the most predominant factor for the μSBS (p < 0.001). A surface with larger nSI%, higher Ra and relatively lower θ


The effects of berteroin on inflammatory mediators and antioxidant enzymes expression in human periodontal ligament cells.

Berteroin is a bioactive substance classified as an isothiocyanate found in cruciferous vegetables such as cabbage, arugula, and salad leaves. In this study, we aimed to determine whether berteroin exerts anti-inflammatory effects on human periodontal ligament cells (HPDLCs), a resident cells of periodontal tissue. Berteroin suppressed interleukin (IL)-1β or tumor necrosis factor (TNF)-α-induced chemokines (C-C motif chemokine ligand (CCL)2, CCL20, C-X-C motif chemokine ligand (CXCL)10, IL-8, and IL-6) production and intercellular adhesion molecule (ICAM)-1 expression in HPDLCs. In addition, berteroin inhibited phosphorylation of IκB kinase (IKK)- α/ β, nuclear factor (NF)- κB p65, and IκB- α and degradation of IκB- α in the NF-κB pathway induced by IL-1 β or TNF- α stimulation. Moreover, berteroin could inhibit signal transducer and activator of transcription (STAT)3 phosphorylation in TNF- α -stimulated HPDLC. Furthermore, berteroin increased the expression of the antioxidant enzymes, heme oxygenase (HO)-1 and NAD(P)H quinone dehydrogenase (NQO)1, in IL-1 β or TNF- α -stimulated HPDLCs. These results suggest that berteroin may decrease the production of inflammatory mediators in HPDLCs by suppressing the NF-κB pathway, and may also decrease the local reactive oxygen species (ROS) production in periodontal lesions by increasing the production of antioxidant enzymes.

Naunyn-Schmiedeberg's Archives of Pharmacology


Effects of erucin on inflammatory mediators and antioxidant enzymes' expression in TNF-α-stimulated human oral epithelial cells.

These results suggest that erucin may provide a new anti-inflammatory agent that can be used in the treatment of periodontitis.


The Effect of Bonding Strategy and Aging on Adhesion to Primary Enamel: An In-Vitro Study.

The 3-ER strategy is optimal for bonding to primary enamel. The etching effect of SE strategies is weaker, resulting in lower µSBS. Thermocycling revealed that the bonding durability of the 1-SE strategy is inferior to that of to multi-step strategies.


Digitally Guided Direct Composite Injection Technique with a Bi-layer Clear Mini-Index for the Management of Extensive Occlusal Caries in a Pediatric Patient: A Case Report.

The injection technique with a bi-layer clear mini-index accurately translated the digital wax-ups into large, final restorations. Precise morphology and shortened chair time enhanced patient satisfaction, but at the expense of multiple visits.


Restoration of a Microdont Using the Resin Composite Injection Technique With a Fully Digital Workflow: A Flexible 3D-printed Index With a Holding Clip.

Direct composite restorations are accepted as a treatment option for microdontia, which is a relatively prevalent condition that poses esthetic concerns. While free-hand composite placement is technique-sensitive and time-consuming, the resin composite injection technique is more straightforward and predictable. A fully digital workflow has been recently introduced, but the 3D-printed resin index is rigid and challenged by undercuts, as opposed to the silicone index. This case report presents a flexible 3D-printed resin index, which can accurately transfer the digitally simulated functional and esthetic form to the final restoration. In addition, a rigid holding clip was designed to stabilize the flexible index.


Study of Streptococcus mutans in Early Biofilms at the Surfaces of Various Dental Composite Resins.

Biofilm deposit on the composite restoration is a common phenomenon and bacterial growth follows the deposition. The study aims to evaluate () early biofilm formation on the surfaces of various dental composite resins by using the real-time quantitative polymerase chain reaction (qPCR) technique. Thirty-two discs, where eight discs were in each group of Filtek Supreme Ultra (FSU; 3M, St. Paul, MN), Clearfil AP-X (APX; Kuraray Noritake Dental Inc., Tokyo, Japan), Beautifil II (BE2; Shofu, Inc., Kyoto, Japan), and Estelite Sigma Quick (ESQ; Tokuyama Dental, Tokyo, Japan), were fabricated and subjected to biofilm formation in an oral biofilm reactor for 12 hours. Contact angles (CA) were measured on the freshly fabricated specimen. The attached biofilms underwent fluorescent microscopy (FM). from biofilms were analyzed using a qPCR technique. Surface roughness (Sa) measurements were taken before and after biofilm formation. Scanning electron microscopy (SEM), including energy dispersive X-ray spectrometer (EDS) analysis, was also performed for detecting relative elements on biofilms. The study showed that FSU demonstrated the lowest CA while APX presented the highest values. FM revealed that condensed biofilm clusters were most on FSU. The qPCR results indicated the highest DNA copies in the biofilm were on FSU while BE2 was the lowest (p < 0.05). Sa test signified that APX was significantly the lowest among all materials while FSU was the highest (p < 0.05). SEM displayed areas with apparently glucan-free more on BE2 compared to APX and ESQ, while FSU had the least. Small white particles detected predominantly on the biofilms of BE2 appeared to be Si, Al, and F extruded from the resin. Differences in early biofilm formation onto various composite resins are dependent on the differences in material compositions and their surface properties. BE2 showed the lowest quantity of biofilm accumulation compared to other resin composites (APX, ESQ, and FSU). This could be attributed to BE2 proprieties as a giomer and fluoride content.


Polymerization shrinkage of light-cured conventional and bulk-fill composites -The effect of cavity depth and post-curing.

decreased significantly between 2 mm and 3 mm (p<0.05), but %VH exceeded 90% even in 5 mm deep cavities. These results indicated that post-curing contributed to lower shrinkage in deeper layers, and that conventional RBCs were not adequately polymerized at the depth of over 3 mm.


Effect of filler load on structural coloration and color adjustment potential of resin composites.

The color-matching ability of single-shade composites Omnichroma (OMN) and Omnichroma Flow (OCF) is ensured by structural color, which arises from monodisperse 260 nm spherical fillers. This study evaluated how filler load influences the color adjustment potential of composite restorations to human teeth of various shades. The performance of composites containing the 260 nm spherical fillers -OMN (79 wt%), OCF (71 wt%), and experimental composites R1 (65 wt%), and R2 (60 wt%)- was compared to two conventional A2-shade composites and a transparent composite. Additionally, the translucency parameter, spectral reflectance, and light transmission properties were assessed. Composites with a lower load of the 260 nm spherical fillers exhibited lower light diffusion and lower reflectance in the yellow-to-red range (580-650 nm), which is characteristic for the structural color of OMN and OCF. The best color adjustment was achieved with OCF, presumably due to its high translucency and uniform spectral reflectance.


Does the thickness of universal-shade composites affect the ability to reflect the color of background dentin?

The recently introduced resin composites with a universal shade are claimed to match any tooth color. In this study, it was examined how composite thickness affects the color adjustment of conventional and universal-shade composites to background dentin. Thirty sound human central incisors of various shade were used, and color differences between their intact labial surfaces, exposed dentin surfaces and composite restorations (thickness 1-3 mm) were evaluated. In addition, the translucency, light transmission characteristics, and spectral reflectance of the composites were measured. The results showed that universal-shade composites outperformed conventional composites of A2 shade in the adjustment of hue and chroma (p<0.05) but not in lightness (p>0.05). The color adjustment potential of all composites significantly decreased as their thickness increased (p<0.05). The effect of thickness on Omnichroma and Omnichroma Flow was less marked, presumably because of their higher translucency (p<0.05) and structural coloration which induces light reflectance in the yellow-to-red range.


Fostering globally competent dental students through virtual team-working, problem-solving and person-centred multi-disciplinary care planning.

Fostering globally competent dental students is important and the acquisition of necessary skill sets could be enhanced through international virtual team-working, problem-solving and person-centred multi-disciplinary care planning activities. These are beneficial for undergraduate dental student training so that they graduate with a broader global perspective and an appreciation of the importance of delivering person-centred culturally sensitive dental care.


The Anti-Inflammatory Effects of Iberin on TNF-α-Stimulated Human Oral Epithelial Cells: In Vitro Research.

Iberin is a bioactive chemical found in cruciferous plants that has been demonstrated to have anticancer properties. However, there have been no reports on its effects on periodontal resident cells, and many questions remain unanswered. The aim of this study was to examine whether iberin had anti-inflammatory effects on human oral epithelial cells, including influences on signal transduction pathway activation in TNF-α-στιμυλατεd χελλσ. Iberin inhibited the production of interleukin (IL)-6 and C-X-C motif chemokine ligand 10 (CXCL10), as well as the expression of vascular cell adhesion molecule (VCAM)-1, inducible nitric oxide synthase (iNOS), and cyclooxygenase (COX)-2 in tumor necrosis factor (TNF)-α-stimulated TR146 cells, a human oral epithelial cell line. Moreover, iberin administration increased the expression of antioxidant signaling pathways, such as Heme Oxygenase (HO)-1 and NAD(P)H quinone dehydrogenase 1 (NQO1). Furthermore, we found that iberin could inhibit the activation of the nuclear factor (NF)-κB, signal transducer and activator of transcription (STAT)3, and p70S6 kinase (p70S6K)-S6 ribosomal protein (S6) pathways in TNF-α-stimulated TR146 cells. In conclusion, iberin reduced inflammatory mediator expression in human oral epithelial cells by preventing the activation of particular signal transduction pathways.


Hydroxyapatite Affects the Physicochemical Properties of Contemporary One-Step Self-Etch Adhesives.

-test with Bonferroni corrections (α = 0.05). When adhesives were manipulated on the HA plate, there was a significant increase in the adhesives' pH. WS and SL of all 1-SEAs decreased when the HA was used. Only SBU showed higher flexural strength when manipulated on the HA compared to the manipulation on TD under dry and wet conditions. For each 1-SEA, the use of HA resulted in significantly higher E in dry and wet conditions. ΔE of all adhesives was smaller with the manipulation on HA than on TD. It was concluded that the manipulation of 1-SEA on a hydroxyapatite plate considerably affected the adhesives' properties.


Caffeic Acid Phenethyl Ester Induces Vascular Endothelial Growth Factor Production and Inhibits CXCL10 Production in Human Dental Pulp Cells

The survival rate of root non-vital teeth is lower than that of vital teeth. Therefore, to preserve the dental pulp is very important. The vascular endothelial growth factor (VEGF) is the most potent angiogenic factor involved in the vitality of dental pulp including reparative dentin formation. Caffeic acid phenethyl ester (CAPE) is a physiologically active substance of propolis and has some bioactivities such as anti-inflammatory effects. However, there are no reports on the effects of CAPE on dental pulp inflammation. In this study, we investigated the effects of CAPE on VEGF and inflammatory cytokine production in human dental pulp cells (HDPCs) to apply CAPE to an ideal dental pulp protective agent. We found that CAPE induced VEGF production from HDPCs. Moreover, CAPE induced the phosphorylation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases (ERK), and stress-activated protein kinase/c-Jun N-terminal kinase (SAP/JNK) in HDPCs. Furthermore, CAPE inhibited C-X-C motif chemokine ligand 10 (CXCL10) production in Pam3CSK4- and tumor necrosis factor-alpha (TNF-α)-stimulated HDPCs. In conclusion, these results suggest that CAPE might be useful as a novel biological material for vital pulp therapy by exerting the effects of VEGF production and anti-inflammatory activities.


Addition of metal chlorides to a HOCl conditioner can enhance bond strength to smear layer deproteinized dentin.


6-(Methylsulfinyl) Hexyl Isothiocyanate Inhibits IL-6 and CXCL10 Production in TNF-α-Stimulated Human Oral Epithelial Cells.

6-(Methylsulfinyl) hexyl isothiocyanate (6-MSITC) is a bioactive substance found in wasabi (Wasabia japonica) and has been reported to have some bioactive effects including anticancer and antioxidant effects. However, there are no reports on its effects on periodontal resident cells, and many points remain unclear. In this study, we aimed to investigate whether 6-MSITC exerts anti-inflammatory effects on human oral epithelial cells, including effects on signal transduction pathway activation. 6-MSITC inhibited interleukin (IL)-6 and C-X-C motif chemokine ligand 10 (CXCL10) production in TNF-α-stimulated TR146 cells, which are a human oral epithelial cell line. Moreover, we found that 6-MSITC could suppress signal transducer and activator of transcription (STAT)3, nuclear factor (NF)-κB, and p70S6 kinase (p70S6K)-S6 ribosomal protein (S6) pathways activation in TNF-α-stimulated TR146 cells. Furthermore, STAT3 and NF-κB inhibitors could suppress IL-6 and CXCL10 production in TNF-α-treated TR146 cells. In summary, 6-MSITC could decrease IL-6 and CXCL10 production in human oral epithelial cell by inhibiting STAT3 and NF-κB activation.


Additive effects of touch-activated polymerization and extended irradiation time on bonding of light-activated adhesives to root canal dentin.

Touch-polymerization activators improved the bond strength of light-activated adhesives to root canal dentin, especially when combined with an extended light-irradiation time.

The purpose of this in vitro study was to investigate the effect of touch-polymerization activators and extended light-irradiation time on the microtensile bond strength (μTBS) of light-activated adhesives.


Application of Sulfinate Agent in Conjunction with HOCl Smear -Layer Deproteinization Improves Dentin Bonding Durability of One-step Self-etch Adhesives.

To evaluate the effect of a sulfinate agent on the bonding durability of one-step self-etch adhesives (1-SEAs) to smear-layer-covered dentin deproteinized with hypochlorous acid (HOCl). Human coronal dentin disks with a standardized smear layer were deproteinized with 100 ppm HOCl solution for 0 s (control), 15 s or 30 s. After rinsing with water for 30 s and air drying, half of the specimens were treated with a sulfinate agent (Scotchbond Universal Dual Cure Activator; SDA) prior to the application of a 1-SEA (Bond Force II [Tokuyama Dental] or Clearfil Universal Bond Quick [Kuraray Noritake]). Microtensile bond strength (µTBS) was measured after 24 h or 10,000 thermal cycles (TC). The data were analyzed by three-way ANOVA with Tukey's post-hoc tests and t-tests at the 0.05 significance level. The 24-h µTBS of both adhesives increased statistically significantly with the HOCl pretreatment for 15 s or 30 s (p < 0.05), but it was not statistically significantly affected by the application of SDA (p > 0.05). However, after TC, the groups treated with the combination of HOCl and SDA maintained their µTBS (p > 0.05), as opposed to untreated dentin and dentin treated with either HOCl or SDA , whose µTBS decreased significantly (p < 0.05). The application of the sulfinate agent did not statistically significantly affect the immediate bond strength of 1-SEAs, and it could not prevent a significant decrease in the bond strength to untreated dentin after thermocycling. However, the sulfinate agent significantly improved the bonding durability of 1-SEAs to HOCl smear -layer deproteinized dentin.


Advanced MIデンティストリー時代に向かって~新しい接着再生歯科治療~

Advanced MIデンティストリー時代に向かって~新しい接着再生歯科治療~


Smear layer deproteinization with NaOCl and HOCl: Do application/wash-out times affect dentin bonding of one-step self-etch adhesives?

This study investigated the influence of application/wash-out times of sodium hypochlorite (NaOCl) and hypochlorous acid (HOCl) on dentin bond strength of one-step self-etch adhesives (1-SEAs). Human coronal dentin discs with a standardized smear layer were pretreated with 6% NaOCl or 100 ppm HOCl for 5 s, 15 s, or 30 s, and washed out with water for 5 s, 15 s or 30 s with or without the application of Clearfil DC Activator (CDA). No pretreatment was used as a control. The discs were bonded with a 1-SEA (Bond Force II or Clearfil Universal Bond Quick) and microtensile bond strength (µTBS) was measured after 24 h. Pretreatment with NaOCl for 15 s and 30 s significantly decreased µTBS (p<0.05), irrespective of wash-out time. The application of CDA recovered µTBS but did not outperform the control group. Conversely, pretreatment with HOCl for 15 s and 30 s followed by 30 s wash-out time significantly increased µTBS of 1-SEAs (p<0.05), regardless of CDA application.


Impaired dental implant osseointegration in rat with streptozotocin-induced diabetes.

In diabetes, high-glucose-induced oxidative stress downregulates proliferation and calcification of BMMSCs, impairing osseointegration and leading to implant failure.

Acid-treated titanium implants were bilaterally placed in the maxillary alveolar ridge of streptozotocin-induced diabetic (DM group) and control rats after extraction of first molars. Histological analysis and micro-push-out test were performed 4 weeks after surgery. Oxidative stress and osteogenic markers in the surrounding bone were quantified by real-time polymerase chain reaction. In the in vitro study, rat bone marrow-derived mesenchymal stem cells (BMMSCs) were cultured on acid-treated titanium discs in a high-glucose (HG) or normal environment. Intracellular reactive oxygen species (ROS), cell proliferation, alkaline phosphatase (ALP) activity, and extracellular calcification were evaluated following antioxidant treatment with N-acetyl-L-cysteine (NAC).


Can a New HEMA-free Two-step Self-etch Adhesive Improve Dentin Bonding Durability and Marginal Adaptation?

The new 2-SEA exhibited stable dentin bonding and increased hydrophobicity resulting from the absence of hydrophilic monomers.


Effect of Surface Polishing on Nano-Hardness and Elastic Modulus of Different Resin Composites after Immersion in Alcoholic Medium


Sodium p-Toluenesulfinate Enhances the Bonding Durability of Universal Adhesives on Deproteinized Eroded Dentin


Effect of Time and Temperature of Air Jet on the Mechanical and Biological Behavior of a Universal Adhesive System.

Applying an air blast at 50°C for 20 seconds increases the DC and microtensile bond strength of the 3M Single Bond Universal Adhesive System to dentin, as well as reduces the transdentinal cytotoxicity of the material to pulp cells.


Eight-year Microtensile Bond Strength to Dentin and Interfacial Nanomechanical Properties of a One-step Adhesive.

Although 8 years of water storage did not decrease the µTBS of CS3+ significantly, the observed failure mode patterns and significantly decreased nanomechanical properties indicated resin degradation of the adhesive and the resin composite.


Effect of Surface Moisture on Bur-cut Dentin on Bonding of HEMA-free and HEMA-containing Universal Adhesives with or without Methacrylamide Monomer.

Dry surfaces enabled obtaining optimal bonding for HEMA-containing adhesives to bur-cut dentin, while wet surfaces enabled optimal bonding for HEMA-free adhesives. Methacrylamide monomers could contribute to the improvement of the initial and long-term bonding performance of universal adhesives to bur-cut dentin.


Regional ultimate tensile strength and water sorption/solubility of bulk-fill and conventional resin composites: The effect of long-term water storage.

increased with depth and storage time, markedly at 3-5 mm after 1 month for conventional composites and after 6 months for bulk-fill composites. The signs of degradation at depths beyond 3 mm suggested that even bulk-fill composites have suboptimal properties in layers more than 3 mm in thickness.


UV-mediated photofunctionalization of indirect restorative materials enhances bonding to a resin-based luting agent.


Clinical effectiveness of direct resin composite restorations bonded using one-step or two-step self-etch adhesive systems: A three-year multicenter study.

The purpose of this multicenter clinical study was to compare the mid-term clinical effectiveness of direct resin composite restorations using one-step or two-step self-etch adhesives (1-SEAs or 2-SEAs). In total, 352 restorations of class I-V cavities and non-carious cervical lesions in vital teeth (1-SEAs; 52 cases, 2-SEAs; 300 cases) were placed at nine university hospitals and evaluated according to the modified USPHS criteria at baseline, and after 1, 2, and 3 years. The recall rates were 86.6% (1 year), 80.1% (2 years), and 62.2% (3 years). Two restorations failed due to fracture during the follow-up, and there was no significant difference in survival rates between 1-SEAs (97.6%) and 2-SEAs (99.4%). However, 2-SEAs exhibited significantly lower occurrences of discoloration, marginal discoloration, fracture, and plaque retention. Moreover, the subjects reported a significantly lower postoperative hypersensitivity and higher overall satisfaction at all evaluation periods if 2-SEAs were used.


間接法修復物のシェードがタッチキュアシステムを有するデュアルキュア型レジンセメントの象牙質接着強さに及ぼす影響

The Japanese Journal of Conservative Dentistry


Color adjustment potential of single-shade resin composite to various-shade human teeth: Effect of structural color phenomenon.

than other tested RCs (p<0.05) and its reflection spectrum ranged from blue to red, while a blue peak was observed with R1 and R2, indicating a higher color adjustment potential of OMN.


Degree of conversion and dentin bond strength of light-cured multi-mode adhesives pretreated or mixed with sulfinate agents.

The influence of sulfinate agents applied as a dentin pretreatment or a mixture with multi-mode one-step self-etch adhesives (1-SEAs) on the degree of conversion (DC) and micro-tensile bond strength (μTBS) of light-cured 1-SEAs was investigated. 1-SEAs Clearfil Universal Bond Quick (UBQ) or Scotchbond Universal Adhesive (SBU) were applied to dentin in etch&rinse or self-etch mode using various application strategies: 1) no pretreatment, 2) pretreatment with 90 wt% ethanol, 3) pretreatment with a sulfinate agent Clearfil DC Activator (UDC) or Scotchbond Universal DCA (SDC), or 4) a mixture of UBQ+UDC or SBU+SDC. μTBS was measured after 24 h. Additionally, DC was measured using attenuated total reflectance Fourier-transform infrared spectroscopy. Pretreatment with sulfinate agents resulted in the highest μTBS and DC, significantly improving them especially in etch&rinse mode. The mixture of sulfinate agents with 1-SEAs was less effective. Pretreatment with ethanol significantly improved μTBS in etch&rinse mode but compromised μTBS in self-etch mode.


Influence of Silane Pretreatment and Warm Air-Drying on Long-Term Composite Adaptation to Lithium Disilicate Ceramic


Influence of central and peripheral dentin on micro-tensile bond strength estimated using a competing risk model.

The bonding performance of dental adhesives is most frequently evaluated using the micro-tensile bond strength (μTBS) test. Despite lacking evidence, peripheral specimens are often discarded to avoid regional variability. This study, therefore, examined whether μTBS to central and peripheral dentin differed. Dentin surfaces of extracted human molars were bonded with various self-etch adhesives, built up with a resin composite, cut into beams, and stressed in tension. Failure mode was classified as adhesive, cohesive in dentin, or other using scanning electron microscopy. Since cohesive failures in dentin were frequent and could confound μTBS results, the data from central/peripheral dentin were analyzed using a Weibull competing risk (CR) model distinguishing failure modes, and its outcomes were compared to a conventional failure mode non-distinguishing Weibull model. Based on the strength data of cohesively failed specimens, the CR model also estimated the strength of dentin. For comparison, the ultimate tensile strength (UTS) of dentin was measured in both regions. The conventional model suggested that peripheral μTBS was higher than central μTBS. Conversely, the CR model disclosed no significant difference in μTBS between the regions but indicated a higher strength of peripheral dentin. This finding was confirmed by UTS measurements, and further supported by the significantly higher incidence of cohesive failures in central dentin. Therefore, peripheral specimens can be used in the μTBS test as well as central ones, but a CR model should be used for statistical analysis if cohesive failures in dentin are frequent, as the strength of peripheral dentin is higher.

Journal of the Mechanical Behavior of Biomedical Materials


Effect of water storage and thermocycling on light transmission properties, translucency and refractive index of nanofilled flowable composites.

The effect of 1-week water storage and subsequent 10,000 thermal cycles on light transmission properties (straight-line transmission (G0), diffusion (DF), the amount of transmitted light (AV)), translucency parameter (TP) and refractive index (RI) of four nanofilled flowable composites was examined. The composites included Filtek Supreme Ultra Flowable Restorative (FSU), Estelite Flow Quick (EFQ), Estelite Universal Flow, (EUF), and Clearfil Majesty ES Flow (ESF), all of A3 shade. For composites with lower filler load (FSU, EFQ), water storage increased G0, AV and TP, but subsequent thermocycling decreased them. An opposite tendency was found for DF. Materials with higher filler load (EUF, ESF) were not significantly affected by aging conditions. RI of EFQ and EUF containing bisphenol A polyethoxy methacrylate (Bis-MPEPP) increased significantly after thermocycling. Additionally, morphological changes were observed using scanning electron microscopy which revealed cracks within nanocluster fillers and dislocation of particles in FSU and EFQ after thermocycling.


Bond strengths of three-step etch-and-rinse adhesives to silane contaminated dentin.

This study aimed to evaluate the effect of silane coupling agent contamination on the microtensile bond strength (µTBS) of 3-step etch-and-rinse adhesives on dentin. Flat occlusal dentin surfaces were prepared and randomly divided into 8 groups (n=20) based on the tested adhesives; Scotchbond Multi-purpose or Optibond FL, with contamination of an experimental silane (2 vol% of 3-m ethacryloxypropyltrimethoxysilane at pH 4.5) before acid-etching, after-etching or after-priming; while the groups without silane contamination served as controls. µTBS data were analyzed by two-way ANOVA and Tukey's HSD tests at a significance level of 0.05. Additional specimens of contaminated dentin were used to analyze changes in the organic molecules by Fourier transform infrared spectroscopy (FTIR). Silane contamination before acid-etching did not significantly change µTBS (p>0.05), but contamination after-etching and after-priming significantly decreased µTBS of both adhesives (p<0.05). Silane contamination had an adverse effect on the dentin bond strength of 3-step etch-and-rinse adhesives especially after-priming.


The effect of curing mode of dual-cure resin cements on bonding performance of universal adhesives to enamel, dentin and various restorative materials.

The effect of curing mode of dual-cure resin cements on the tensile bond strength (TBS) of universal adhesives to enamel, dentin, zirconia, lithium disilicate ceramics (LDS), feldspathic porcelain (FP), and a Pd-Au alloy was evaluated. The substrates were bonded using Tokuyama Universal Bond (TUB) or Scotchbond Universal Adhesive (SBU), followed by luting with Estecem II (ECII) or Rely-X Ultimate (RXU), respectively, which were used either in light-curing or self-curing mode. The TBS test was performed after 24 h or 5,000 thermal cycles. Light-curing significantly improved the 24-h TBS of TUB/ECII to enamel, dentin and FP, as well as the TBS of SBU/RXU to all substrates except LDS. After thermal cycling, light-curing significantly increased the TBS of both adhesives/cements to dentin, but significant differences between curing modes were seldom observed for other substrates. This suggested that light-curing is essential for the hydrophilic dentin, but self-curing might be sufficient for other substrates.


Effect of smear layer deproteinization with enzyme solutions on bonding efficacy of one-step self-etch adhesives

International Journal of Adhesion & Adhesives


Long-term evaluation of warm-air treatment effect on adaptation of silane-containing universal adhesives to lithium disilicate ceramic.

The effect of warm air-blowing on the sealing ability of two one-bottle and one two-bottle silane-containing universal adhesives (UAs) applied to lithium disilicate ceramics (LDS) was evaluated. Tapered cavities prefabricated in LDS blocks (IPS e.max CAD) were treated by the adhesives, air-blown either with normal air (23±1°C) or warm air (60±5°C), and filled with a flowable resin composite. Interfacial gap formation was observed using swept-source optical coherence tomography immediately after filling, after 24 h, 5,000 and 10,000 thermal cycles, and an additional 1-year water storage. Specimens bonded using normal air-blown one-bottle UAs exhibited a significantly higher gap formation than the two-bottle UA (p<0.001), and detached within 24 h. Warm air-blowing significantly decreased the gap formation of one-bottle UAs (p<0.001), but the specimens dislocated within 24 h or during thermocycling. The two-bottle UA withstood all aging procedures and warm air-blowing significantly decreased its 1-year gap formation compared to normal air-blowing (p=0.002).


3D imaging of proximal caries in posterior teeth using optical coherence tomography.

Optical coherence tomography (OCT) can create cross-sectional images of tooth without X-ray exposure. This study aimed to investigate the diagnostic accuracy of 3D imaging of OCT for proximal caries in posterior teeth. Thirty-six human molar teeth with 51 proximal surfaces visibly 6 intact, 16 slightly demineralized, and 29 distinct carious changes were mounted to take digital radiographs and 3D OCT images. The sensitivity, specificity and area under the receiver operating characteristic curve (AUC) for the diagnosis of enamel caries and dentin caries were calculated to quantify the diagnostic ability of 3D OCT in comparison with digital radiography. Diagnostic accuracy was evaluated by the agreement with histology using weighted Kappa. OCT showed significantly higher sensitivity, AUC and Kappa values than radiography. OCT can be a safer option for the diagnosis of proximal caries in posterior teeth that can be applied to the patients without X-ray exposure.


A competing risk model for bond strength data analysis.

Merging all bond-strength data into one dataset irrespective of the failure mode may result in a severe underestimation of bond strength, especially in groups with low incidence of adhesive failures. Bond-strength data analysis using a CR model could provide more accurate estimates of bond strength, and strength estimates for cohesive failures which were apparently independent of bond strength could serve as an internal validity indicator of the CR model.


Effect of preheating on cytotoxicity and physicochemical properties of light-cured calcium-based cements.

The aim of this study was to evaluate the degree of conversion, cytotoxicity, solubility and pH of photopolymerizable calciumbased cements submitted to preheating. The degree of conversion was analyzed by Fourier transform infrared, cytotoxicity by the MTT test and solubility through loss of mass. The data were subjected to statistical tests (ANOVA / Tukey's, p<0.05). The photopolymerizable materials showed a low degree of conversion, regardless of preheating. All materials caused a reduction in cell viability at 24 hours and 7 days, with the Dycal (control) being more cytotoxic. Heat had a positive effect on Biocal at 7 days. Dycal is the most soluble material. Heat had no effect on the solubility or pH of the polymerizable materials. It is concluded that photopolymerizable calcium-based cements have a low degree of conversion and are soluble, which results in mild to moderate cytotoxicity.


Replacing mandibular central incisors with a direct resin-bonded fixed dental prosthesis by using a bilayering composite resin injection technique with a digital workflow: A dental technique.

A straightforward technique is presented for an interim or short-term definitive esthetic replacement of missing anterior teeth requiring no tooth preparation. Composite resins are injected into transparent silicone indices fabricated from 3-dimensional-printed casts of a digital waxing. The dentin core is formed of a durable short fiber-reinforced injectable composite resin and veneered with an enamel-shade composite resin for enhanced esthetics. Besides being noninvasive, this technique is more straightforward than traditional options, reducing chair time while providing an accurate outcome.


Functional and Esthetic Rehabilitation of Severely Eroded Dentition Using Direct Resin Composite Restorations: A Case Report

Tooth Wearによる機能的・審美的障害に対して直接法コンポジットレジン修復を行った1症例

 Purpose: In severe cases of erosive tooth wear. the tooth form and color are altered, leading to the need for functional and esthetic enhancement. Conventionally, indirect crown or onlay restorations requiring tooth preparation have been applied as suitable restorative methods for such cases. However, the development of adhesive systems and resin composite has expanded the treatment modalities and enabled the concept of minimal intervention dentistry. This case report describes a minimally invasive full-mouth reconstruction of eroded teeth using direct resin composite restorations.

 Case: The patient was a 48-year-old male experiencing decreased vertical dimension of occlusion (VDO) and non-esthetic appearance in the anterior region. After diagnostic waxing, it was decided to increase the VDO by 1 mm in both the maxillary and mandibular dentition (2 mm in total), creating an appropriate space for direct resin composite build-ups. To enhance the esthetic appearance, anterior teeth were also labially veneered. Subsequently, a protective night guard was delivered. As part of a periodical maintenance program, slight occlusal adjustments were performed if necessary and the restorations were repolished to maintain high gloss. After 1 year and 11 months, the restoration of the mandibular right second molar partially fractured, but it was directly repaired according to the manufacturer's instructions. The outcome at the 3-year follow-up was excellent both functionally and esthetically. No apparent wear of the placed restorations was observed, suggesting that this minimally invasive approach could be a valid treatment option for severely eroded teeth. The advantage of the presented restorative procedure is that it does not require large-scale tooth preparation, preserving the sound dental tissues. Further clinical research is necessary to verify the long-term effectiveness of full-mouth reconstructions with direct resin composite restorations.

 Conclusion: Decreased VDO due to severe erosive tooth wear was successfully restored using direct resin composite build-ups and veneers. The reconstruction enhanced the esthetics and function, and the outcome remained excellent after 3 years.

 目的 : 近年, 歯科診療における直接法コンポジットレジン修復は, 適用範囲が顕著に拡大しており, さまざまな原因で起こる歯の硬組織の部分的な欠損に対して, 窩洞形成による保持形態付与を必要とせず, 健全歯質を最大限に保存できる修復法である. このように, 現状の歯冠形態に接着操作や充塡操作を経て, 歯質に材料を接着させることで修復が成立するという特徴は, コンポジットレジン直接修復でのみ対応可能な治療計画を提案し, 従来の歯科治療の概念に新たな選択肢を与えている. 酸蝕などの 「Tooth Wear」 により歯冠形態や咬合が崩壊した症例においても, その程度に応じた接着修復の適用により治療の難易度を低下させることも可能となる. 長期間の生活習慣 (酸性飲料の習慣的摂取・ブラキシズム) の影響により, 臼歯部咬合面の形態変化と咬合高径の低下による機能障害, 前歯部の変色と歯冠長減少による審美障害とを併発した口腔内状況に対し, 健全歯質への切削を最小限にした直接法コンポジットレジン修復により対応し, これまでのところ良好な結果を得ているので報告する.

 症例 : 48歳男性. 全顎的Tooth Wearによる臼歯部咬合高径の低下がみられ, これによる前歯部の歯冠長減少とエナメル質の不均一な変色による審美障害が認められた. 全顎的な歯周炎はなく, すべての歯に病的な動揺は認められない. 2016年8月より, 上下顎の臼歯部咬合面にそれぞれ1.0mmの厚さで順次フロアブルレジン充塡を行い, 臼歯部で計2.0mmの咬合挙上を行った. 臼歯部咬合面の修復完了後, 2017年3月より, 前歯部へのコンポジットレジンによるダイレクトベニア修復を行った. 形態修正と研磨を行い, メインテナンスと経過観察に移行し, 3カ月に1回程度の間隔で予後の確認を継続している.

 結果 : 修復完了より1年11カ月経過時点で, 下顎左側第二大臼歯でのコンポジットレジンの部分破折が一度認められたが, 業者指示の接着ステップに従い補修修復にて対応した. 修復完了後3年1カ月経過後の時点において, 良好な予後が確認されている.

 結論 : 重度Tooth Wearにより臼歯部咬合高径が低下した機能・審美障害に対し, コンポジットレジン修復を活用した臼歯部の咬合再構成とダイレクトベニア修復で対応し, 3年経過後時点で良好な予後を得ることができた.

The Japanese Journal of Conservative Dentistry


Effect of heat treatment on cytotoxicity and polymerization of universal adhesives.

To assess, in vitro, the influence of heat air treatment on cytotoxicity and degree of conversion (DC) of universal self-etch adhesives (Ambar Universal APS, Scotchbond Universal Adhesive, and Tetric N-Bond Universal) in an NIH/3T3 fibroblast cell culture. Samples were divided into three groups: 1) no heat treatment (control), 2) 37°C and 3) 60°C heat treatment before photopolymerization. Cytotoxicity was analyzed by MTT assay and the DC by FTIR. All adhesives heated at 60°C showed reduced cytotoxicity levels when compared with those heated at 37°C. In general, DC of Ambar Universal APS presented the highest DC than Scotchbond Universal Adhesive and Tetric N-Bond Universal, and the hot air treatment do not influence the conversion. Heat treatment at 60°C was able to reduce the cytotoxicity of universal self-etch adhesives, even, the heat treatment does not enhances the DC.


Post-orthodontic recontouring of anterior teeth using composite injection technique with a digital workflow.

Post-orthodontic recontouring using direct composite restorations is well accepted by patients due to low cost and non-invasiveness. However, in complicated cases, the free-hand technique is time-consuming and technique-sensitive. The presented composite injection technique with a digital workflow significantly simplifies and expedites the composite placement while predictably enhancing the treatment outcome.

Journal of Esthetic And Restorative Dentistry


Air-blowing strategies for improving the microtensile bond strength of one-step self-etch adhesives to root canal dentin.

The effect of different air-blowing strategies using a prototype of a newly developed clinically applicable warm air-blowing device on the microtensile bond strength (μTBS) of one-step self-etch adhesives (1-SEAs) to human root-canal dentin was evaluated. Post cavities (8 mm depth, 1.5 mm diameter) were prepared and bonded with four 1-SEAs. Air-blowing was performed using normal air (23±1°C) for 10 or 20 s; warm air (60±1°C) for 10 or 20 s; or their combination for 10 s (5 s normal, 5 s warm) or 20 s (10 s normal, 10 s warm). After filling with corresponding core materials and 24-h water storage, μTBS test was performed. For three of the 1-SEAs, combined air-blowing for 20 s significantly increased μTBS compared to other air-blowing strategies (p<0.05). This suggests that the combination of normal and warm air-blowing for 20 s can enhance solvent evaporation from 1-SEAs, thus resulting in their improved bonding performance to root-canal dentin.


Effect of antioxidant/reducing agents on the initial and long-term bonding performance of a self-etch adhesive to caries-affected dentin with and without smear layer-deproteinizing

International Journal of Adhesion & Adhesives


Effect of smear layer deproteinization with HOCl solution on the dentin bonding of conventional and resin-modified glass-ionomer cements.

The effect of smear layer-deproteinizing pretreatment using hypochlorous acid (HOCl) on the micro-shear bond strengths (μSBS) of conventional and resin-modified glass-ionomer cements (GIC) to dentin was investigated and compared with demineralizing pretreatment with polyacrylic acid (PAA). Three GICs: Fuji IX GP Extra (restorative conventional GIC), GC Fuji II LC EM (restorative resin-modified GIC), and GC Fuji Luting EX (luting resin-modified GIC), were used. One hundred fifty human molars were divided into groups (n = 10) according to the cements and dentin pretreatments; no pretreatment (control), 10 s PAA pretreatment, and HOCl pretreatment for 5, 15, or 30 s. After 24 h, μSBS was tested and the data were statistically analyzed using a two-way ANOVA, followed by Tukey's post-hoc test. HOCl pretreatment significantly increased μSBS of conventional GIC compared to the control group. For resin-modified restorative GIC, 5 s HOCl deproteinization significantly increased μSBS, while longer application times did not. There was no significant difference between HOCl-pretreated and control groups of resin-modified luting GIC. PAA pretreatment increased the μSBS of all cements significantly. In conclusion, smear layer deproteinization with HOCl can enhance the dentin bonding of conventional GIC. However, the residual radicals may adversely affect the polymerization of resin-modified GICs.


Degree of Conversion Contributes to Dentin Bonding Durability of Contemporary Universal Adhesives.

The degree of conversion of contemporary universal adhesives positively correlates with the bond strength to dentin. The correlation is more marked after thermocycling, suggesting that a high degree of conversion is required for long-term dentin bonding durability. Purpose: The objectives of this study were to evaluate the micro-tensile bond strength (μTBS) of five contemporary universal adhesives to dentin after 24 hours and thermocycling (TC), to measure their degrees of conversion (DC) and to test the correlation between μTBS and DC.Methods and Materials: Four commercially available universal adhesives, Prime&Bond universal (PBU), Ecosite Bond (EB), G-Premio Bond (GPB), and Clearfil Universal Bond Quick (UBQ), and one experimental adhesive, UBQ without an amide monomer (UBQ-A), were used in this study. For the μTBS test, midcoronal dentin of 50 human molars was exposed, ground using 600-grit SiC paper, and the adhesives were applied according to the manufacturers' instructions. After resin-composite buildup and 24-hour water storage, one-half of the specimens were subjected to 15,000 thermal cycles. The specimens were sectioned into beams and stressed in tension at a crosshead speed of 1 mm/min until failure. The DC of adhesives applied to dentin was evaluated using attenuated total reflectance Fourier-transform infrared spectroscopy immediately after light-curing. All data were statistically analyzed at a significance level of 0.05.Results: The highest μTBSs were obtained with UBQ, UBQ-A, and PBU, which were not significantly different from each other both after 24 hours and TC. The μTBS of GPB was lower compared with the aforementioned adhesives, but significantly only after TC, and the lowest μTBSs were obtained with EB. TC did not affect the μTBSs of UBQ, UBQ-A, and PBU significantly, but a significant decrease was observed with GPB and EB. The highest DC was obtained with PBU and UBQ, followed by 2-hydroxyethyl methacrylate-rich adhesives UBQ-A and EB, which exhibited significantly lower DCs. The DC of GPB could not be determined because the reference peak at 1608 cm-1 was not detected in its spectra. A significant positive correlation was shown between μTBS and DC after 24 hours (r=0.716) and TC (r=0.856).Conclusion: μTBS and DC were positively correlated, more markedly after TC, which suggests that DC may be an important factor for bond durability.


Hot air stream reduces cytotoxicity of light-cured calcium hydroxide based cements.

Dental pulp capping, dental cements, calcium hydroxide, cell survival.

Journal of Clinical and Experimental Dentistry


医歯学総合研究科歯学系大学院生対象の国際歯科臨床教育コース(Essential Expertise for Clinical Dentistry)に対する評価

The Journal of the Stomatological Society, Japan


Effect of smear layer deproteinization with chemo-mechanical caries removal agents on sealing performances of self-etch adhesives.

Chemo-mechanical CRAs could effectively remove the organic phase of enamel and dentin smear layer. The papain enzyme-based gel Papacarie could improve the sealing performance of the self-etch adhesives to both enamel and dentin.

Papacarie significantly reduced gap formation with both self-etch adhesives at all locations, compared to the control group (p < 0.05). In contrast, increased gap formation was observed with Carisolv and NaOCl. In most groups, CSE exhibited significantly lower gap formation than GBP (p < 0.05). ATR-FTIR revealed a significant decrease in the amide:phosphate ratio for all the deproteinizing agents (p < 0.05).


Universal adhesives - a new direction in the development of adhesive systems


The combined effect of light-illuminating direction and enamel rod orientation on color adjustment at the enamel borders of composite restorations.

The line-of-vision angle would affect the perception of color adaptation at the enamel borders in the composite restorations.


Subsequent application of bonding agents to a one-step self-etch adhesive - Its effect with/without previous light-curing.

BZF-21 and CSP improved the μTBS of GPB to dentin both immediately and after TC. Higher μTBSs were obtained when GPB remained uncured prior to BA application.


Incorporation of a hydrophilic amide monomer into a one-step self-etch adhesive to increase dentin bond strength: Effect of application time.

UBQ showed the highest μTBS at 0 s application time among all the adhesives. When the application time was prolonged from 0 s to 10 s, only UBQ showed no significant difference. The hydrophilic amide monomer increased μTBS with reduction in Wsp and increase in the UTS and may allow a shortened application time.


The effect of flowable composite lining and dentin location on microtensile bond strength and internal fracture formation.

The objective of this study was to determine the effect of flowable composite lining and dentin location on internal dentin fracture formation in the microtensile bond strength (MTBS) test using swept-source optical coherence tomography (SS-OCT). MTBS test beams (1.0×1.0 mm) were prepared from human superficial and deep dentin, which was bonded with a self-etch adhesive (Clearfil SE Bond) and hybrid composite resin (Clearfil AP-X), with or without flowable lining (Clearfil Majesty ES-Flow). We tested 4 groups according to placement technique (with vs. without flowable liner) and dentin (superficial vs. deep) locations. Cross-sectional 2D images of the bonded interface were obtained before and after the MTBS test. Internal dentin fracture after MTBT was observed as a bright zone in SS-OCT. Flowable lining significantly reduced internal fracture formation in dentin (p<0.05). Dentin location significantly influenced MTBS (p<0.05), and this was reduced by flowable lining usage.


Effect of light-curing time on light-cure/post-cure volumetric polymerization shrinkage and regional ultimate tensile strength at different depths of bulk-fill resin composites.

The aim of this study was to investigate volumetric polymerization shrinkage (VS), using swept-source optical coherence tomography (SS-OCT), of bulk-fill composites with different light-curing strategies; immediately after light-irradiation and after 24 h, and to evaluate their regional ultimate tensile strength (UTS) at different curing depths. The immediate VS after photo-polymerization decreased when the curing light-curing time was reduced from 20 to 10 to 5 s. On the other hand, their VS values after 24 h significantly increased due to the post-cure polymerization, resulting in similar VS values at all the light-curing times. Five seconds light-curing decreased the regional UTS of resin composites after the 24 h period compared with the 10 and 20 s light-curing regimes; therefore, the remarkable progress of post-cure polymerization after light-curing for a short time would not lead to an improvement in the mechanical properties of resin composites. The influence of the light-curing time on the curing depth was dependent upon the bulk-fill composite material.


Ultra-high-speed videography of resin-dentin interface failure dynamics under tensile load.

UHS videography enabled visualization of the fracture dynamics at the resin- dentin interfaces under tensile load. However, the resolution at such high frame rate was insufficient to classify the failure mode as precisely as that of SEM. Nevertheless, UHS videography can provide more detailed information about the fracture origin and propagation.


The Simplified Posterior Direct Flowable Composite Bridge Restoration without Reinforcing Fibers: A Case Report

大臼歯部1歯欠損症例にフロアブルコンポジットレジンのみを用いた単純化した術式によりダイレクトブリッジ修復を行った1症例

 Purpose: In cases of a single-tooth edentulous space in the posterior region, we usually consider either a 3-unit fixed partial denture or an implant. However, minimal invasive treatment with resin composite is still the best option in some situations. This case report describes a minimal invasive and simplified direct composite bridge restoration without reinforcing fibers.

 Case: A 29-year-old female patient presented with a missing mandibular left first molar that had been recently extracted because of root fractures that had made the tooth unrestorable. A two-step self-etch adhesive system was applied after additional phosphoric acid etching of enamel surfaces which were slightly cut. Only flowable resin composite was used for the fabrication of the direct resin composite bridge. The prognosis after 9 months was good.

 Conclusion: A technique for using flowable composite resin to construct a direct resin composite bridge was demonstrated. It is important to consider the direct composite restoration option even for single-tooth replacement cases in the posterior region when the clinical and economic circumstances preclude an implant or fixed partial denture as a treatment choice. Direct composite bridge restoration is a valid treatment option for esthetic and functioning dental restoration when used under appropriate clinical circumstances. It is also important to note that the eventual repair or replacement of this restoration is much easier in comparison to dental ceramics as the substrate is composite resin. For clinical patients such as the one presented in this paper, the direct resin composite bridge is satisfactory for their restorative needs. However, further clinical research is necessary to verify the clinical effectiveness of direct bridge restorations.

 目的 : 接着歯学の発展に伴い, Minimal Intervention Dentistryのコンセプトに基づく歯質接着システムとコンポジットレジンを用いた直接法接着修復治療は, 臨床的有効性と経済的効率性の観点から, 典型的な窩洞のみならず, 空隙歯列の空隙閉鎖, 歯冠形態の改善, 前歯部少数歯欠損補綴までさまざまな症例に多く用いられている. 少数歯欠損補綴に関しては, コンポジットレジンのみで修復する方法は強度が不足することから, より高い強度と破折抵抗性を求めて, ファイバー繊維がしばしば併用されてきた. しかし術式は単純ではなく, 高度な技術が必要である. 近年, 接着性レジンの接着性能やフロアブルコンポジットレジンの物性が向上したことから, 術式がシンプルなコンポジットレジンのみの修復が改めて見直されている. しかし, その報告はあまり多くない. 今回, 大臼歯部1歯欠損補綴に対して最新の接着システムとフロアブルコンポジットレジンのみを用いたダイレクトブリッジ修復を行い, これまでのところ良好な結果を得ているので報告する.

 症例 : 29歳女性. 下顎左側第一大臼歯は歯根破折の診断により抜歯された. 欠損隣接歯には全周に2, 3mm程度のポケットが観察されたのみで, 全顎的な歯周炎はなく, すべての歯に病的な動揺は認められなかった. また, 矯正歯科治療後の患者で咬合に問題は認められなかった. あらかじめ, 作業用模型上欠損部にポンティックのワックスアップを行い, ポンティック部の咬合面・基底面のシリコンコアを作成した. 2018年2月, 欠損側エナメル質には, リン酸ジェルを用いて酸処理を行った後, ツーステップセルフエッチングシステムを用いてメーカー指示どおり歯面処理を行い, フロアブルコンポジットレジンのみを用いて積層充塡を行いながらダイレクトブリッジ構造を構築した. 咬合調整および形態修正研磨を行い, 1週間後に予後を確認した.

 結果 : 9カ月経過後の時点においても, 良好な予後が確認されている.

 結論 : 本症例では, フロアブルコンポジットレジンのみを用いた直接法修復によって大臼歯部1歯欠損補綴治療を完了し良好な予後を得た. ファイバー繊維による補強構造を必要とせず, フロアブルコンポジットレジンのみの修復により良好な予後が得られたことから, 単純化された術式によるダイレクトブリッジ修復の臨床応用が今後期待される.

The Japanese Journal of Conservative Dentistry


The Influence of a Touch-cure System on the Micro-tensile Bond Strength of Self-etch Adhesives to Root Canal Dentin

タッチキュアがセルフエッチシステムの深部根管壁象牙質接着性能に及ぼす効果

 Purpose: Based on the concept of minimal intervention dentistry and developments in adhesive technology, direct resin composite build-up restorations are increasingly performed for endodontically treated teeth. The adhesive systems and dual-cure resin composites use a touch-cure system which contains a special accelerator to promote chemical polymerization. This accelerator enhances the polymerization of the adhesive in deeper areas where light energy is attenuated, such as post cavities. The purpose of this study was to evaluate the influence of the touch-cure system on the micro-tensile bond strength of selected self-etch adhesive systems to root canal dentin.

 Methods: One two-step self-etch adhesive system, Clearfil SE Bond 2 (SE2) with/without Clearfil DC Activator (DCA), and one one-step self-etch adhesive system, Clearfil Universal Bond QuickER (UBQ), were applied to a root canal post cavity (depth 8 mm, diameter 1.5 mm) according to the manufacturer's instructions followed by a dual-cure resin composite build-up (Clearfil DC Automix ONE). After immersion of the specimens in water for 24 hours, micro-tensile bond strengths in coronal and apical regions were evaluated. The micro-tensile bond strengths were statistically analyzed using a two-way ANOVA and Student's t-test with Bonferroni correction (α=0.05).

 Results: Pretesting failures of specimens were not observed in this study. Micro-tensile bond strengths in the apical region were significantly lower than those in the coronal region in all adhesive systems. In the coronal region, a significant difference was seen only between SE2+DCA and UBQ, while there was no significant difference among all tested adhesive systems in the apical region.

 Conclusion: Within the limitations of this study, the effect of the touch-cure system on micro-tensile bond strength to root canal dentin was found in neither the one-step nor the two-step self-etch adhesive system.

 目的 : 近年, 生活歯のみならず根管処置歯に対しても接着性コンポジットレジンを用いた直接法支台築造法が行われる機会が増加している. ポスト窩洞における根管壁象牙質への接着では, 窩底部は照射光エネルギーが十分に到達しにくいことから, これまでデュアルキュア型接着システムおよびデュアルキュア型コンポジットレジンが多く用いられてきた. 現在では, デュアルキュア型コンポジットレジンとの間のタッチキュア (接触重合) によって, ボンドへの光照射が困難な部位に関しても重合性の向上を目指すシステムが紹介されている. 本研究では, タッチキュアがセルフエッチシステムの根管壁象牙質への接着性能に及ぼす効果を検討した.

 材料と方法 : ヒト抜去下顎小臼歯12本に径1.5mm, 深さ8mmのポスト窩洞を形成した後, 1ステップセルフエッチシステム, クリアフィルユニバーサルボンドQuickER (UBQ, クラレノリタケデンタル) および2ステップセルフエッチシステム, クリアフィルメガボンド2 (SE2, クラレノリタケデンタル) を用いて業者指示どおり接着処理を行った. SE2のボンドについては, デュアルキュア型コンポジットレジンとの間でタッチキュアを促進するクリアフィルDCアクティベーター (DCA, クラレノリタケデンタル) との等量混和の有無によって2群を設定した. ボンドへの光照射は, LED光照射器を用いて業者指示どおりそれぞれ10秒間行った. その後, クリアフィルDCコアオートミックスONEを充塡し, LED光照射器を使用して20秒間光照射を行った. 各接着システムについて, 根管接着試料は37°C水中に24時間保管後, 歯根軸に対し直角方向に棒状試片 (断面0.6×0.6mm) を32本作製し, 1窩洞の棒状試片を均等に分け, 合計16本の歯冠側群と根尖側群を設定した. その後, クロスヘッドスピード1mm/minにて微小引張り接着試験を行った. 得られた結果は歯冠側および根尖側, 4試料ずつ分類し, 2-way ANOVAおよびBonferroni補正を用いたt検定を用いて有意水準5%にて統計処理を行った.

 結果 : すべての群において, 根尖側の接着強さは歯冠側の接着強さより有意に低い値を示した. 歯冠側では, SE2+DCA群はUBQ群より有意に高い値を示したものの, SE2+DCA群とSE2群間, SE2群とUBQ群間の間には有意差は認められなかった. 一方, 根尖側ではすべての材料間に有意差は認められなかった. 根尖側における破断面の観察から, UBQ群, SE2+DCA群におけるBlister Formationが認められた.

 結論 : 1ステップセルフエッチシステム, 2ステップセルフエッチシステムともに深部根管壁象牙質では接着強さが減少し, タッチキュアの付与による接着性能向上効果は認められなかった. 溶媒が残存しやすく, 照射光の到達しにくいポスト窩洞深部の重合性の改善に関する課題が示唆された.


Effects of UVB and UVC irradiation on cariogenic bacteria in vitro.

measurements. Direct UV-LED irradiation with both UVB and UVC showed strong bactericidal effects. UVB showed superior bactericidal effect through 0.5-mm-thick dentin than did UVC, especially after demineralization. These results suggest that UVB irradiation could be utilized for the prevention and management of dental caries.

) were also taken after irradiation. In addition, the bactericidal effects of irradiation against S. mutans under 0.5 mm-thick dentin were compared using culture tests and OD


The repair bond strength to resin matrix in cured resin composites after water aging.

The repair microshear bond strengths (µSBSs) to resin matrices in 4 different cured-composites after water storage (0, 60 s, 1 week, 1 month) were evaluated. Three different adhesive application methods to the cured-composites were performed; (1) none, (2) onestep self-etch adhesive application, and (3) one-step self-etch adhesive application with a silane coupling agent. Degree of conversion (DC) of the composite discs was determined using ATR/FT-IR with a time-based spectrum analysis. Initially, the amount of un-reacted resin monomers in the repaired cured-composite contributed to the bonding performance of newly-filled uncured-composite to resin matrix of the cured-composite. Adhesive application could not improve their repair µSBS. After 1-month of water-storage, the repair µSBS was dependent on material, which either reduced or did not and was not influenced by their amount of un-reacted resin monomers. When repairing aged composite resin, the appropriate adhesive application procedures were different among resin composites.


International Dental Education Course for Clinical Expertise at Tokyo Medical and Dental University Graduate School


Smear layer-deproteinization: Improving the adhesion of self-etch adhesive systems to caries-affected dentin


Storage Temperature Influences the Carbamide Peroxide Concentration of at Home Bleaching Agents

Biomedical Journal of Scientific & Technical Research


The strategies used for curing universal adhesives affect the micro-bond strength of resin cement used to lute indirect resin composites to human dentin.

We evaluated the effect of different curing strategies for universal adhesives on micro-tensile bond strength (μTBS) between resin cement and dentin and/or between resin cement and indirect resin composite. Flat coronal dentin surfaces and composite resin disks were pretreated with silane-containing universal adhesives, with or without light-curing on the dentin-side and/or composite resin disk-side. Resin disks were luted onto the pretreated dentin surfaces with the corresponding dual-cure adhesive resin cements and light-cured, and cut into beams after 24-h water storage. After 0 or 10,000 thermocycles (5ºC/55ºC) in a water bath, the μTBS of the composite resin disk-dentin beam was tested. The μTBS was highest when universal adhesives were applied to both the dentin- and the indirect composite resin disk-side, followed by light-curing. Thermocycling decreased μTBS in all but the Scotchbond Universaltreated group, with light-curing on both sides. The effect of curing strategies is dependent upon the materials.


Stress distribution in tooth resin core build-ups with different post-end positions in alveolar bone level under two kinds of load directions.

This study aimed to evaluate influence of different post-end positions in alveolar bone level on stress distributions in resin-core build-up tooth under different load directions. Three-dimensional mathematical models of a root-filled mandibular premolar tooth were constructed. Resin post and core were built-up with six post lengths: 0, 1, 2, 3, 4, and 6 mm. Finite element analysis calculated stress distributions with oblique load of 400 N to buccal cusp 45 degree from buccal side or from lingual side. The 3 mm-post length (post-end position equal to cancellous bone level) caused highest equivalent stress of post-end compared with the shorter or longer post length. When change of load direction, the direction of maximum shear stress became completely opposite at mesiodistal cervical edge of core-part without a change of the magnitude. Changing shear stress direction would increase risk of debonding at mesiodistal cervical edge.


The effect of warm air-blowing on the microtensile bond strength of one-step self-etch adhesives to root canal dentin.

The μTBS of 1-SEAs to root canal dentin was improved by using warm air-blowing.


Effect of Water Aging of Adherend Composite on Repair Bond Strength of Nanofilled Composites.

Microhybrid composite was a more suitable material for composite repair than nanofilled composite, due to adhesion to exposed, larger silica fillers. S-PRG filler and nanocluster filler in the nanofilled composites played a slight role in improving their repair bonding performances with the bonding agents tested.


Effect of Polymerization Accelerator on Bond Strength to Eugenol-Contaminated Dentin.

The application of a polymerization accelerator on eugenol-contaminated dentin prior to adhesive resin application increased the μTBS of both the three-step etch-and-rinse and two-step self-etch adhesive.


Smear layer-deproteinizing improves bonding of one-step self-etch adhesives to dentin.

application could enhance the quality of dentin for bonding to one-step self-etch adhesives, resulting in the improving μTBS, eliminating hybridized smear layer and preventing reticular nanoleakage formation in resin-dentin bonding interface.


The effect of five kinds of surface treatment agents on the bond strength to various ceramics with thermocycle aging.

This study evaluated the effects of ceramic surface treatment agents on shear bond strengths to ceramic materials with and without thermocycling. Ceramic plates were prepared from feldspathic ceramic; AAA, lithium disilicate ceramic material; IPS e.max Press, zirconia ceramic; Lava. Ceramic surfaces were pretreated with one of five surface treatment agents (Clearfil PhotoBond mixed with Porcelainbond activator (PB), Clearfil SE One mixed with Porcelainbond activator (SO), Ceramic Primer (CP), Universal Primer (UP), Scotchbond Universal (SU)), and then a resin cement (Clapearl DC) was filled. After 0, 5,000, and 10,000 thermocycles, micro-shear bond strengths between ceramic-cement interfaces were determined. SU exhibited significantly lower initial bond strength to AAA and e.max than PB, SO, CP, and UP. For Lava, PB, SO, CP and SU exhibited higher initial bond strengths than UP. Thermocycles reduced bond strengths to all the ceramic materials with any surface treatment.


Dentin Bonding Durability of Two-step Self-etch Adhesives with Improved of Degree of Conversion of Adhesive Resins.

The higher DC of adhesive resins of two-step self-etch adhesives resists water aging and improves the initial bond strengths and durability of the resin-dentin bond.

CSE2 showed significantly higher DC than CSE. The µTBS of CSE2 was significantly higher than that of CSE in all water storage periods. One-year water storage decreased the µTBS of CSE; however, it did not decrease that of CSE2. Regarding the polymerized adhesive resins, the elastic modulus of CSE2 was significantly higher than that of CSE before and after water immersion (p < 0.001), and the water sorption of CSE was higher than that of CSE2.


Influence of water immersion on the mechanical properties of fiber posts.

The prefabricated glass fiber posts and structures using resin composites with glass fiber posts were affected by water immersion.


矯正歯科治療後のコンポジットレジン再修復の長期予後報告

矯正歯科治療後のコンポジットレジン再修復の長期予後報告


【歯質に対する接着耐久性を考える】 ボンディング材の劣化が接着耐久性に及ぼす影響


Effects of chlorhexidine in self-etching adhesive: 24 hours results.

It is known that chlorhexidine (CHX) does not inhibit micro-tensile bond strengths (MTBS) when it is used in etch-and-rinse adhesives. In that technique, CHX is applied to dentin as a primer after phosphoric acid-etching before bonding with Single Bond. It would be more convenient if it is possible to incorporate CHX into the adhesive. The purpose of this study was to compare the MTBS and the FT-IR percent conversion of an all-in-one self-etching adhesives contained varying concentration of CHX. Extracted human third molars were bonded with a control all-in-one adhesive or experimental versions containing 0.5, 1, 2 or 5% CHX. The MTBS and the percent conversion of experimental adhesives containing up to 1% CHX were not significantly CHX-free control adhesives. However, addition of 2 or especially 5% CHX experimental adhesives produced significant reductions in both the MTBS and the percent conversion.


Color shifting at the border of resin composite restorations in human tooth cavity.

All resin composite restorations in the tooth cavities produced the color shifting of resin composite and tooth at the border. For deep cavity, resin composites with higher diffused light transmission property showed higher color shifting at the border, while for shallow cavity, the straight-line as well as diffused light transmission of resin composite affected the color shifting at the border. Clinically, diffused light transmission property of resin composites may contribute to the color shifting at the border of resin composite restoration regardless of cavity depth, resulting in better color matching.


Effect of air-drying dentin surfaces on dentin bond strength of a solvent-free one-step adhesive.

The purpose was to evaluate the effect of air-drying dentin surfaces on the microtensile bond strength (μTBS) of a solvent-free onestep adhesive (Bond 1 SF). Twelve human molars were ground with 600-grit SiC paper. Before applying bonding agent, the dentin surface was rinsed with distilled water and blot-dried with tissue paper, followed by air-drying for 0, 3, 30, and 60 s using with a dental air syringe. After applying and curing Bond 1 SF, resin composite was incrementally built up. Specimens were then stored in distilled water for 24 h and then μTBSs were measured at a cross-head speed of 1 mm/min. Higher μTBS were observed when the dentin surface was air-dried for 3 s (33.2±6.8MPa)>0 s (26.7±4.5MPa)>30 s (22.6±5.5MPa)=60 s (20.4±5.0MPa). The results suggested that prolonged air-drying of the dentin surface removed water and decreased the bond strengths of Bond 1 SF.


Effect of smear layer treatment on dentin bond of self-adhesive cements.

The purpose of this study was to compare the dentin bond strength of three self-adhesive cements with smear layer pretreatments using a calcium-chelating agent (EDTA) and deproteinizing solution (NaOCl) and to evaluate their interfacial characteristics. Smear layer-covered dentin surfaces were pretreated with EDTA for 60 s, NaOCl for 5 and 15 s, or none. Three self-adhesive cements; Clearfil SA luting (Kuraray Medical), Rely X Unicem clicker (3M ESPE) and Breeze (Pentron) were applied to the dentin surfaces. After 24-h water storage, shear bond strengths to dentin were determined. In addition, nanoleakage evaluation at the interface was performed using FE-SEM and EDS. EDTA-pretreatment significantly improved the bond strength of BR (p<0.05) and NaOCl-pretreatment for 15 s significantly improved the bond strength of RX (p<0.05). On the other hand, for SA, both pretreatments significantly decreased bond strength to dentin (p<0.05). Nanoleakage formation was observed in various amounts at the cement-dentin interfaces.


Influences of composite-composite join on light transmission characteristics of layered resin composites.

Resin composite placed in layers exhibited reduced straight-line light transmission and increased diffusion transmission compared with bulk-filled resin composite. The layering technique affected the translucency and color rendition of resin composite.


Effect of smear layer characteristics on dentin bonding durability of HEMA-free and HEMA-containing one-step self-etch adhesives.

The purpose of this study was to evaluate the effect of smear layer characteristics on the dentin bonding durability of HEMA-free and HEMA-containing one-step self-etch adhesives. Xeno V (XV; HEMA-free), G BOND PLUS (GB; HEMA-free) and Clearfil S(3 )Bond (S(3); HEMA-containing), were applied to dentin surfaces prepared with either #180- or #600-grit SiC paper according to manufacturers' instructions. Bond strengths to dentin were determined using µTBS test after 24-hour, 6-month, and 1-year water storage. In addition, nanoleakage evaluation was performed using an SEM. The smear layer characteristics affected water-tree nanoleakage formation in the adhesive layers of XV and GB, which contributed to a reduction in µTBS after 6-month water storage, while the characteristics did not affect the µTBS of S(3). However, regardless of the smear layer characteristics, 1-year water storage significantly reduced the µTBS of all the adhesives and was associated with an increase in failures at the adhesive-composite interface.


The influence of light intensities irradiated directly and indirectly through resin composite to self-etch adhesives on dentin bonding.

This study was designed to evaluate effects of light-irradiated intensities directly and indirectly through resin composites to one- and two-step self-etch adhesives on dentin bonding. One-step (Clearfil S(3) Bond; TS, Bond Force; BF) or two-step (Clearfil SE Bond; SE) self-etch adhesives was applied to dentin surface. The adhesive agent was light-cured with light-intensity of 350 or 600 mW/cm(2), and then resin composite with different colors (translucent or opaque shade) was filled and light-cured with the same light-intensity as the bonding procedure. After 24 h water storage, bond strengths to dentin were determined using µTBS test. For the 600 and 350 mW/cm(2) groups, translucent shade resin obtained higher µTBS than opaque shade resin. Using SE and BF, the 350 mW/cm(2) group in translucent shade resin was higher µTBS than the 600 mW/cm(2) group in opaque shade resin, while TS showed no different µTBS between them.


Long-term evaluation of water sorption and ultimate tensile strength of HEMA-containing/-free one-step self-etch adhesives.

For the HEMA-containing adhesives, Wsp increased and UTS decreased over time. On the other hand, for the HEMA-free adhesive, Wsp and UTS did not significantly change even after 360-day water-storage.


Effect of composite post placement on bonding to root canal dentin using 1-step self-etch dual-cure adhesive with chemical activation mode.

This study evaluated the effect of composite post placement and/or light-irradiation of dual-cure resin composite on adhesion to root canal dentin using the chemical activation mode of a 1-step self-etch dual-cure adhesive. Post spaces were prepared in extracted premolars. Root canal spaces were applied with Unifil Core EM Self-Etching Bond, which was chemically-polymerized, and then filled with Unifil Core EM with or without the placement of composite post. Half the specimens of each group were light-cured for 10 seconds and the other half were chemically-cured in darkness for 30 minutes. After 24 h storage, microtensile bond strengths (µTBS) at the coronal and apical regions were measured. When light-curing, placement of the composite post significantly reduced the µTBS to root canal dentin. On the other hand, when chemical-curing, there was no significant difference in µTBS between with and without placement of the composite post.


Dentin bond durability and water sorption/solubility of one-step self-etch adhesives.

The purpose of this study was to evaluate the dentin bonding durability of three HEMA-containing one-step self-etch adhesives after one-year water storage and to measure the amounts of their water sorption/solubility. OptiBond All-In-One (OP), Bond Force (BF) and Clearfil S³Bond (S³) were applied to the dentin surfaces according to manufacturers' instructions. Bond strengths to dentin were determined using µTBS test after water storage for 24 hours, six months, and one year. In addition, water sorption and solubility of the polymerized adhesives were measured. The µTBS of S³ and OP significantly decreased after one year. On the other hand, for BF there were no significant differences in µTBS between all storage periods. There were significant differences in water sorption and solubility among the adhesives (BF>S³>OP). The initial amounts of water sorption and solubility of the three adhesives did not affect their bonding durability to dentin.


Translucency, opalescence and light transmission characteristics of light-cured resin composites.

At the 0.5mm thickness, the translucency (TP) and opalescence (OP) of resin composites had a significant correlation with a diffuse transmission property (DF). When more than 1.0mm thickness of resin composites, translucency and opalescence were influenced by the thickness, in which translucency significantly decreased and opalescence significantly increased.


Relationship between mechanical properties of one-step self-etch adhesives and water sorption.

The moduli of elasticity and ultimate tensile strengths of the adhesives fell significantly after water-storage. Water sorption depended on the constituents of the adhesive systems. The percent decreases in the ultimate tensile strengths of the adhesives were related to water sorption, while the percent reductions in the moduli of elasticity of the adhesives were not related to water sorption.


The effect of dentin preparation with an ultrasonic abrasion on the microtensile bond strength of self-etch adhesive systems

International Chinese Journal of Dentistry


Effect of light exposure of dual-cured resin cement on dentin bond strength

光照射の有無がデュアルキュア型レジンセメントの象牙質接着強さに与える影響


Improving the effect of NaOCl pretreatment on bonding to caries-affected dentin using self-etch adhesives.

The effects of NaOCl pretreatment on bonding of both self-etch adhesives were dependent upon type of dentin (normal and caries-affected dentin) and the treatment time.


Durability of resin-dentin bonds to water- vs. ethanol-saturated dentin.

Higher 24-hour resin-dentin bond strengths are created when ethanol is used to replace water during wet bonding. This in vitro study examined if ethanol-wet-bonding can increase the durability of resin-dentin bonds over longer times. Five increasingly hydrophilic experimental resin blends were bonded to acid-etched dentin saturated with water or ethanol. Following composite build-ups, the teeth were reduced into beams for 24-hour microtensile bond strength evaluation, and for water-aging at 37 degrees C for 3, 6, or 12 months before additional bond strength measurements. Although most bonds made to water-saturated dentin did not change over time, those made to ethanol-saturated dentin exhibited higher bond strengths, and none of them fell over time. Decreased collagen fibrillar diameter and increased interfibrillar spacing were seen in hybrid layers created with ethanol-wet-bonding. Increases in bond strength and durability in ethanol-wet-bonding may be due to higher resin uptake and better resin sealing of the collagen matrix, thereby minimizing endogenous collagenolytic activities.


Membrane permeability properties of dental adhesive films.

This study evaluated the permeability properties of five experimental resin membranes that ranged from relatively hydrophobic to relatively hydrophilic to seal acid-etched dentin saturated with water or ethanol. The experimental resins (R1, R2, R3, R4, and R5) were evaluated as neat bonding agents or as solutions solvated with ethanol (70% resin/30% ethanol). The quality of dentin sealing by these experimental resins was expressed in terms of reflection coefficients calculated as the ratio of the effective osmotic pressure to the theoretical osmotic pressure of test solutions. The effective osmotic pressure produced across resin-bonded dentin was induced in hypertonic solutions (CaCl(2) or albumin) at zero hydrostatic pressure. The outward fluid flow induced by these solutions was brought to zero by applying an opposing negative hydrostatic pressure. The least hydrophilic resins blends, R1 and R2, exhibited significantly (p < 0.05) higher reflection coefficients than the most hydrophilic resins (R4 and R5) in both conditions of dentin saturation (water and ethanol). The reflection coefficients of neat resins were, in general, significantly higher when compared with their corresponding solvated versions in both conditions of dentin saturation. In dentin saturated with ethanol, bonding with neat or solvated resins, resulted in reflection coefficients that were significantly higher when compared with the results obtained in dentin saturated with water. Reflection coefficients of CaCl(2) (ca. 1 x 10(-4)) were significantly lower (p < 0.05) than for albumin (ca. 3 x 10(-2)). Application of hydrophobic resins may provide better sealing of acid-etched dentin if the substrate is saturated with ethanol, instead of water.

Journal of Biomedical Materials Research. Part B, Applied Biomaterials


Improvement of Bonding to Caries-affected Dentin

う蝕象牙質に対する2ステップ・セルフエッチ接着システムの接着性能の改良

After caries removal and cavity preparation for an adhesive restoration, large areas of the cavity floor are composed of caries-affected dentin, however previous studies have reported that the bond strength to caries-affected dentin was lower than that to normal dentin. The physical and chemical characteristics of caries-affected dentin are very different from those of normal dentin, due to a loss of mineral content during the carious process. Also, the characteristics of smear layers of normal and caries-affected dentin differ because the composition of a smear layer is generally similar to the originating tissue; thus, it is assumed that the smear layer in caries-affected dentin is enriched with organic phase, resulting from the loss of minerals. Sodium hypochlorite (NaOCl) is a nonspecific proteolytic agent that effectively removes organic compounds at room temperature. Therefore, pre-treatment of the smear layer with NaOCl could eliminate the collagen phase. The aim of this study was to evaluate the effect of pre-treatment of NaOCl with or without a reducing agent on the microtensile bond strength to normal and caries-affected dentin. Twenty extracted human molars with occlusal caries were used. The occlusal dentin surface was ground flat to expose normal and caries-affected dentin using #600 SiC paper under running water. The dentin surface including caries-affected dentin was treated with 6% NaOCl solution for 30s followed by application with or without aromatic sulfinate solution (Accel®, SunMedical) for 10 and 30s, or none (control). After rinsing off, the treated dentin surface was applied with Clearfil Mega Bond FA® (Kuraray Medical) according to the manufacturer's instructions and the crown was built up with resin composite. After storage in water for 24 hours, the bonded specimens were serially sectioned into 0.7 mm-thick slabs and trimmed to an hour-glass shape with 1mm2 cross-section isolated by normal or caries-affected dentin, and then subjected to a micro-tensile bond test. Data were analyzed by one and two-way ANOVA, and post hoc test(Dunnett T3 and T-test, p<0.05). For the control group, caries-affected dentin showed a significantly lower bond strength of the self-etch system than normal dentin. However, NaOCl treatment of the dentin surface followed by application of a reducing agent before the bonding procedure improved the bond strength to caries-affected dentin, in which there was no significant difference between bond strength of normal and caries-affected dentin. The effect of the reducing agent on bonding to caries-affected dentin treated with NaOCl depended upon the application time.

う蝕象牙質へのレジンの接着性能は,健全象牙質に比べ低いことが知られている.その原因として,う蝕象牙質の形態学的構造,生化学的性状および機械的性状が,健全象牙質とは著しく異なっていることなどが挙げられている.また,被着象牙質表面を覆っているスミヤー層の性状も接着性能に影響を及ぼす可能性がある.象牙質切削時に表面に形成されるスミヤー層は,被切削体と構成成分は同じであると考えられている.したがって,う蝕象牙質削面に形成されるスミヤー層は,健全象牙質のスミヤー層と比べて有機成分の割合が多いと思われる.本研究では,う蝕象牙質内層(う蝕罹患(影響)象牙質:caries-affected dentin)へのレジンの接着性能の改良を目指して,スミヤー層の構造がう蝕象牙質と健全象牙質とで異なることに着目し,スミヤー層表面の有機成分を溶解・除去することができる次亜塩素酸ナトリウム水溶液による前処理が,う蝕罹患象牙質への2ステップ・セルフエッチ接着システム(クリアフィルメガボンドFA®,クラレメディカル)の接着強さに及ぼす影響について検討した.その結果,次亜塩素酸ナトリウム水溶液30秒処理後,還元効果のある芳香族スルフィン酸塩を主成分としたアクセル®(サンメディカル)にて30秒間処理することにより,う蝕罹患象牙質に対するクリアフィルメガボンドFA®の接着強さを,無処理-健全象牙質に対する接着強さと同程度に改善させることができた.また,健全象牙質を次亜塩素酸ナトリウム水溶液30秒処理後,アクセル®にて30秒間処理した場合と無処理-健全象牙質に対する接着強さの間に有意差は認められなかった.健全象牙質とう蝕罹患象牙質におけるスミヤー層の性状の違いが,2ステップ・セルフエッチ接着システムのう蝕罹患象牙質に対する接着強さの低下の大きな要因である可能性が示唆された.

The Japanese Journal of Conservative Dentistry


Influence of hydrostatic pulpal pressure on the microtensile bond strength of all-in-one self-etching adhesives.

The microTBS of the two all-in-one adhesive systems decreased when PP was applied. However, the microTBS of both self-etching primer adhesives did not decrease under PP.


Effect of wet vs. dry testing on the mechanical properties of hydrophilic self-etching primer polymers.

Self-etching primers and adhesives contain very hydrophilic methacrylate monomers that result in high water sorptions by their polymers. Water sorption plasticizes the polymers and lowers their mechanical properties. The purpose of this work was to rank the hydrophilicity of a series of acidic primers by their Hoy's solubility parameters (delta) to determine if there was a significant relationship between the delta of polymers and their mechanical properties. A series of six acidic primer blends containing a fixed concentration of phenyl-P but variable amounts of 2-hydroxyethyl methacrylate (HEMA), 2,2 bi[4-(2-hydroxy-3-methacryloyloxy)propane (BisGMA), and triethylene-glycol dimethacrylate (TEGDMA) was formulated and their Hoy's solubility parameters calculated. The polymers were cast into small 'I' beams and light-cured. The modulus of elasticity (E) and ultimate tensile strength (UTS) were measured in dry polymers and after immersion in water for 24 h. The results showed significant correlations between E and UTS under dry or wet conditions. Both E and UTS fell significantly when the specimens were immersed in water. After water immersion, the E and UTS showed significant correlations with Hoy's delta(p) values. Both E and UTS correlated significantly with the BisGMA concentration of the polymers, either wet or dry. The percentage changes in E or UTS were significantly correlated with the water sorption of the polymers.


Use of Hoy's solubility parameters to predict water sorption/solubility of experimental primers and adhesives.

Self-etching primers and adhesives contain very hydrophilic acidic monomers that result in high water sorption/solubilities of their polymers. However, the chemical composition of these products varies widely. The purpose of this work was to vary the chemical composition of experimental self-etching primers and adhesives to determine if the water sorption/solubility of the polymers were affected in a predictable manner. The Hoy's solubility parameters of these mixtures were calculated to permit ranking of the degree of hydrophilicity of the polymers. Water sorption/solubility was measured according to ISO 4049. The results showed highly significant (R(2) = 0.86, P < 0.001) correlations between water sorption and Hoy's solubility parameter for polar forces (delta(p)) of the polymers. Similar correlations were obtained between polymer solubility and delta(p). When these results were compared with previously published results obtained with more hydrophobic resins, excellent correlations were obtained, indicating that Hoy's delta(p) values may be used to predict the water sorption behavior of methylmethacrylate polymers.


Effect of simulated pulpal pressure on all-in-one adhesive bond strengths to dentine.

The muTBS of OBF bonded specimens was lowered more by simulated PP than by storage time; specimens bonded with FBS were not sensitive to storage time in the absence of PP, but showed lower bond strengths at 1 and 3 months in the presence of PP.


Bonding durability of a self-etching primer system to normal and caries-affected dentin under hydrostatic pulpal pressure in vitro.

Hydrostatic pulpal pressure significantly reduced the bond strength to normal dentin after 1-month storage (P< 0.05), but did not affect the bond strength to caries-affected dentin.


Micro-tensile bond strengths of the newly developed one-step bonding system "One-Up Bond F Plus"

新規ワンステップボンディング材"One-Up Bond F Plus"の象牙質接着性能