Exploring the Widespread Effectiveness of Maxillomandibular Advancement


Effect of palatine tonsil hypertrophy on tongue posture and maxillofacial dentition: A pharyngeal airway computational fluid dynamics study


Does rapid maxillary expansion improve nasal airway obstruction? A computer fluid dynamics study in patients with nasal mucosa hypertrophy and obstructive adenoids

Rapid maxillary expansion (RME) expands the maxillary dentition laterally and improves nasal airway obstruction. However, the incidence of nasal airway obstruction improvement after RME is approximately 60%. This study aimed to clarify the beneficial effects of RME on nasal airway obstruction in specific pathologic nasal airway diseases (nasal mucosa hypertrophy and obstructive adenoids) using computer fluid dynamics. Sixty subjects (21 boys; mean age 9.1 years) were divided into 3 groups according to their nasal airway condition (control, nasal mucosa hypertrophy, and obstructive adenoids), and those requiring RME had cone-beam computed tomography images taken before and after RME. These data were used to evaluate the nasal airway ventilation condition (pressure) using computer fluid dynamics and measure the cross-sectional area of the nasal airway. The cross-sectional area of the nasal airway significantly increased after RME in all 3 groups. The pressures in the control and nasal mucosa groups significantly reduced after RME but did not change significantly in the adenoid group. The incidence of improvement in nasal airway obstruction in the control, nasal mucosa, and adenoid groups was 90.0%, 31.6%, and 23.1%, respectively. The incidence of improvement in nasal airway obstruction after RME depends on the nasal airway condition (nasal mucosa hypertrophy and obstructive adenoids). In patients with nonpathologic nasal airway conditions, the obstruction may be sufficiently improved with RME. Furthermore, to some extent, RME may be effective in treating nasal mucosa hypertrophy. However, because of obstructive adenoids, RME was ineffective in patients with nasal airway obstruction.

American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO)


Conditioned Medium from Stem Cells of Human Exfoliated Deciduous Teeth Partially Alters the Expression of Inflammation-associated Molecules of Mouse Condylar Chondrocytes via Secreted Frizzled-related Protein 1


Therapeutic benefits of factors derived from stem cells from human exfoliated deciduous teeth for radiation-induced mouse xerostomia

Radiation therapy for head and neck cancers is frequently associated with adverse effects on the surrounding normal tissue. Irreversible damage to radiation-sensitive acinar cells in the salivary gland (SG) causes severe radiation-induced xerostomia (RIX). Currently, there are no effective drugs for treating RIX. We investigated the efficacy of treatment with conditioned medium derived from stem cells from human exfoliated deciduous teeth (SHED-CM) in a mouse RIX model. Intravenous administration of SHED-CM, but not fibroblast-CM (Fibro-CM), prevented radiation-induced cutaneous ulcer formation (p < 0.0001) and maintained SG function (p < 0.0001). SHED-CM treatment enhanced the expression of multiple antioxidant genes in mouse RIX and human acinar cells and strongly suppressed radiation-induced oxidative stress. The therapeutic effects of SHED-CM were abolished by the superoxide dismutase inhibitor diethyldithiocarbamate (p < 0.0001). Notably, quantitative liquid chromatography-tandem mass spectrometry shotgun proteomics of SHED-CM and Fibro-CM identified eight proteins activating the endogenous antioxidant system, which were more abundant in SHED-CM than in Fibro-CM (p < 0.0001). Neutralizing antibodies against those activators reduced antioxidant activity of SHED-CM (anti-PDGF-D; p = 0.0001, anti-HGF; p = 0.003). Our results suggest that SHED-CM may provide substantial therapeutic benefits for RIX primarily through the activation of multiple antioxidant enzyme genes in the target tissue.


Iroquois homeobox 3 regulates odontoblast proliferation and differentiation mediated by Wnt5a expression.

Iroquois homeobox (Irx) genes are TALE-class homeobox genes that are evolutionarily conserved across species and have multiple critical cellular functions in fundamental tissue development processes. Previous studies have shown that Irxs genes are expressed during tooth development. However, the precise roles of genes in teeth remain unclear. Here, we demonstrated for the first time that Irx3 is an essential molecule for the proliferation and differentiation of odontoblasts. Using cDNA synthesized from postnatal day 1 (P1) tooth germs, we examined the expression of all Irx genes (Irx1-Irx6) by RT-PCR and found that all genes except Irx4 were expressed in the tooth tissue. Irx1-Irx3 a were expressed in the dental epithelial cell line M3H1 cells, while Irx3 and Irx5 were expressed in the dental mesenchymal cell line mDP cells. Only Irx3 was expressed in both undifferentiated cell lines. Immunostaining also revealed the presence of IRX3 in the dental epithelial cells and mesenchymal condensation. Inhibition of endogenous Irx3 by siRNA blocks the proliferation and differentiation of mDP cells. Wnt3a, Wnt5a, and Bmp4 are factors involved in odontoblast differentiation and were highly expressed in mDP cells by quantitative PCR analysis. Interestingly, the expression of Wnt5a (but not Wnt3a or Bmp4) was suppressed by Irx3 siRNA. These results suggest that Irx3 plays an essential role in part through the regulation of Wnt5a expression during odontoblast proliferation and differentiation.

Biochemical and Biophysical Research Communications


睡眠歯科の用語集 第2版 日本睡眠歯科学術用語部会


Persistent pediatric obstructive sleep apnea treated with skeletally anchored transpalatal distraction

Nasomaxillary expansion by skeletally anchored TPD improves OSA in children without transverse maxillary deficiency that were previously treated by RPE. A nearly parallel anterior-posterior opening of the mid-palatal suture achieves enlargement of the entire nasal passage with improvement of the airflow characteristics in the nasal and pharyngeal airway. The improved airflow characteristic is significantly correlated with the improved polysomnographic findings, thus demonstrating that nasomaxillary expansion in previously expanded patients is a viable treatment option.


当科における5年間の障害児・有病児の初診時実態調査

当科における5年間の障害児・有病児の初診時実態調査

障害児や有病児への理解の深まりから社会環境や福祉制度の整備が進みつつあるが，障害や全身疾患をもつ児が地域において疾病予防も含めた歯科医療を受けられる環境がいまだ十分にあるとは言えず，実情に応じた環境整備が求められる．そこで，今回，平成25年度から平成29年度に当科を受診した児のうち障害児・有病児の5年間の初診時実態調査を行い，過去に当科で行った調査と比較し，近年の変化を検討した．初診患者1,301名のうち，障害児・有病児の割合は49

The Japanese Journal of Pediatric Dentistry


Fibroblast growth factor 2 suppresses the expression of C-C motif chemokine 11 through the c-Jun N-terminal kinase pathway in human dental pulp-derived mesenchymal stem cells

The regulation of the mesenchymal stem cell (MSC) programming mechanism promises great success in regenerative medicine. Tissue regeneration has been associated not only with the differentiation of MSCs, but also with the microenvironment of the stem cell niche that involves various cytokines and immune cells in the tissue regeneration site. In the present study, fibroblast growth factor 2 (FGF2), the principal growth factor for tooth development, dental pulp homeostasis and dentin repair, was reported to affect the expression of cytokines in human dental pulp-derived MSCs. FGF2 significantly inhibited the expression of chemokine C-C motif ligand 11 (CCL11) in a time- and dose-dependent manner in the SDP11 human dental pulp-derived MSC line. This inhibition was diminished following treatment with the AZD4547 FGF receptor (FGFR) inhibitor, indicating that FGF2 negatively regulated the expression of CCL11 in SDP11 cells. Furthermore, FGF2 activated the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinases (JNK) in SDP11 cells. The mechanism of the FGFR-downstream signaling pathway was then studied using the SB203580, U0126 and SP600125 inhibitors for p38 MAPK, ERK1/2, and JNK, respectively. Interestingly, only treatment with SP600125 blocked the FGF2-mediated suppression of CCL11. The present results suggested that FGF2 regulated the expression of cytokines and suppressed the expression of CCL11 via the JNK signaling pathway in human dental pulp-derived MSCs. The present findings could provide important insights into the association of FGF2 and CCL11 in dental tissue regeneration therapy.


Papadopoulou, Nasal ventilation and rapid maxillary expansion(RME): a randomized trial

To assess three rapid maxillary expansion (RME) appliances in nasal ventilation. Three-arm parallel randomized clinical trial. Sixty-six growing subjects (10-16 years old) needing RME as part of their orthodontic treatment were randomly allocated (1:1:1 ratio) to three groups of 22 patients receiving Hyrax (H), Hybrid-Hyrax (HH), or Keles keyless expander (K). The primary outcome of nasal ventilation (pressure and velocity) and secondary outcomes (skeletal, dental, soft tissue, and nasal obstruction changes) were blindly assessed on the initial (T0) and final (T1, 6 months at appliance removal) cone-beam computed tomography (CBCT) data by applying computational fluid dynamics (CFD) method. Differences across groups were assessed with crude and adjusted for baseline values and confounders (gender, age, skeletal maturation, expansion amount, mucosal/adenoid hypertrophy, nasal septum deviation) regression models with alpha = 5%. Fifty-four patients were analysed (19H, 21HH, 14K). RME reduced both nasal pressure (H: -45.8%, HH: -75.5%, K: -63.2%) and velocity (H: -30%, HH: -58.5%, K: -35%) accompanied with nasal obstruction resolution (H: 26%, HH: 62%, K: 50%). Regressions accounting for baseline severity indicated HH expander performing better in terms of post-expansion maximum velocity (P = 0.03) and nasal obstruction resolution (P = 0.04), which was robust to confounders. Mucosal/adenoid hypertrophy and nasal septum deviation changes were variable, minimal, and similar across groups. The HH resulted in significantly greater increase in the nasal cross-sectional area (62.3%), anterior (14.6%), and posterior (10.5%) nasal widths. Nasal obstruction resolution was more probable among younger (P = 0.04), skeletally immature (P = 0.03), and male patients (P = 0.02) without pre-treatment mucosal hypertrophy (P = 0.04), while HH was associated with marginal greater probability for obstruction resolution. RME resulted in improvement of nasal skeletal parameters and simulated ventilation with the former being in favour of the HH and the latter not showing significant differences among the three appliances. Attrition in the K group due to blocked activation rods possibly leading to limited sample to identify any existing group differences. Replacement of blocked Keles expanders for finalizing treatment. The protocol was not published before the trial commencement. Australian and New Zealand Clinical Trial Registry; ACTRN12617001136392.


Computational fluid dynamics analysis in patients with nasal disease

The Showa University Journal of Medical Sciences


Detailed evaluation of the upper airway in the Dp(16)1Yey mouse model of Down syndrome.

A high prevalence of obstructive sleep apnea (OSA) has been reported in Down syndrome (DS) owing to the coexistence of multiple predisposing factors related to its genetic abnormality, posing a challenge for the management of OSA. We hypothesized that DS mice recapitulate craniofacial abnormalities and upper airway obstruction of human DS and can serve as an experimental platform for OSA research. This study, thus, aimed to quantitatively characterize the upper airway as well as craniofacial abnormalities in Dp(16)1Yey (Dp16) mice. Dp16 mice demonstrated craniofacial hypoplasia, especially in the ventral part of the skull and the mandible, and rostrally positioned hyoid. These changes were accompanied with a shorter length and smaller cross-sectional area of the upper airway, resulting in a significantly reduced upper airway volume in Dp16 mice. Our non-invasive approach, a combination of computational fluid dynamics and high-resolution micro-CT imaging, revealed a higher negative pressure inside the airway of Dp16 mice compared to wild-type littermates, showing the potential risk of upper airway collapse. Our study indicated that Dp16 mice can be a useful model to examine the pathophysiology of increased upper airway collapsibility of DS and to evaluate the efficacy of therapeutic interventions for breathing and sleep anomalies.


Effect of adenoids and tonsil tissue on pediatric obstructive sleep apnea severity determined by computational fluid dynamics.

Obstructive sleep apnea (OSA) is a respiratory disorder caused by the obstruction of the upper airway during sleep. The most common cause of pediatric OSA is adenotonsillar hypertrophy. Adenotonsillectomy is the first-line treatment for pediatric OSA; however, OSA persists in a significant number of patients due, in part, to the method of evaluating enlarged adenoids and tonsil tissue. The reason for these effects on OSA severity is not clear. This study aimed to establish a method to diagnose the need for adenoidectomy or tonsillectomy. Twenty-seven Japanese children (mean age 6.6 years) participated in this study, undergoing polysomnography and computed tomography examination. Pharyngeal airway morphology (adenoids and tonsil tissue size, volume, and cross-sectional area [CSA]) and pressure on the upper airway were evaluated at each site using computational fluid dynamic analysis. Apnea-hypopnea index (AHI) showed a strong linear association with maximum negative pressure (P) (AHI = -0.055* events/h P -1.326, R² = .805). The relationship between minimum CSA (CSA) and P was represented by an inversely proportional fitted curve (P = -4797/CSA -5.1, R² = .507). The relationship between CSA and AHI was also represented by an inversely proportional fitted curve (AHI = 301.6 events/h/CSA, R² = .680). P greatly increased if CSA became ≤ 30 mm². The negative pressure of each site increased when CSA measured ≤ 50 mm². In children, when the CSA for each site is ≤ 50 mm², AHI is likely to be elevated, and the patient may require tonsillectomy or adenoidectomy.


Relationship between pharyngeal airway depth and ventilation condition in mandibular setback surgery: A computational fluid dynamics study.

This study aimed to determine the anteroposterior depth (APD) of the pharyngeal airway (PA) where post-operative PA obstruction was predicted, using computer fluid dynamics (CFD), in order to prevent obstructive sleep apnoea after mandibular setback surgery. Nineteen skeletal Class III patients (8 men; mean age, 26.7 years) who required mandibular setback surgery had computed tomography images taken before and 6 months after surgery. The APD of each site of the four cross-sectional reference planes (retropalatal airway [RA], second cervical vertebral airway, oropharyngeal airway and third cervical vertebral airway) were measured. The Maximum negative pressure (Pmax) of the PA was measured at inspiration using CFD, based on a three-dimensional PA model. Intersite differences were determined using analysis of variance and the Friedman test with Bonferroni correction. The relationship between APD and Pmax was evaluated by Spearman correlation coefficients and non-linear regression analysis. The smallest PA site was the RA. Pmax was significantly correlated with the APD of the RA (r = .628, P < .001). The relationship between Pmax and the APD-RA was fitted to a curve, which showed an inversely proportional relationship of Pmax to the square of the APD-RA. Pmax substantially increased even with a slight reduction of the APD-RA. In particular, when the APD-RA was 7 mm or less, Pmax increased greatly, suggesting that PA obstruction was more likely to occur. The results of this study suggest that APD-RA is a useful predictor of good PA ventilation after surgery.


How does distraction osteogenesis maxillary expansion (DOME) reduce severity of obstructive sleep apnea?

Distraction osteogenesis maxillary expansion (DOME) is a reliable method to expand the nasal floor and hard palatal vault in adults with obstructive sleep apnea (OSA). DOME results in a reduction in the apnea-hypopnea index (AHI) and subjective report of improved nasal breathing. Using rhinomanometry augmented computational fluid dynamic (CFD) modeling, we propose a mechanism of how DOME reduces upper airway pharyngeal collapse in adults with OSA. A retrospective cohort with 20 subjects and mean age of 29.6 ± 8 years who completed DOME at Stanford University from September 2014 to April 2016. Subjects were included if polysomnography, airway morphology, and rhinomanometry were available for use. From the CBCT data, 3D nasal and pharyngeal airway model were generated. Numeric CFD simulation of the airway models were analyzed under the following conditions: (1) the volume of air was flowing at a velocity of 300 cm/s, (2) the wall surface was not slippery, and (3) the simulations were repeated 1000 times to calculate mean values. Statistical analyses using SPSS v24 software included paired t tests, nonparametric Wilcoxon rank test, Friedman test with Bonferroni correction, and Spearman's correlation coefficients (p < 0.05). Mean AHI improved from 17.8 ± 17.6 to 7.8 ± 7.1 events per hour (p < 0.001). Mean lowest oxygen saturation improved from 88.2 ± 7.2 to 90.9 ± 4.2% (p < 0.05). Mean airflow velocity within the nasal airway decreased from 15.6 ± 7.3 to 7.4 ± 2.1 m/s (p < 0.001) after DOME. Mean negative pressure of the nasal airway, retropalatal airway, oropharyngeal airway, and hypopharyngeal airway is reduced from - 158.4 ± 115.3 to - 48.6 ± 28.7 Pa, from - 174.8 ± 119.9 to - 52.5 ± 31.3 Pa, from - 177.0 ± 118.4 to - 54.9 ± 31.8 Pa and from - 177.9 ± 117.9 to - 56.9 ± 32.1 Pa (p < 0.001), respectively. AHI positively correlated with nasal flow velocity (p < 0.05) and negatively correlated with pharyngeal airway pressure (p < 0.05). ODI was positively correlated with nasal velocity (p < 0.05) and negatively correlated with nasal airway pressure (p < 0.05), retropalatal airway pressure (p < 0.001), oropharyngeal airway pressure (p < 0.001), and hypopharyngeal airway pressure (p < 0.05). Anatomic expansion of the nasal floor with widening of the hard palatal vault from DOME is associated with reduction of nasal airflow velocity and downstream reduction of negative pressure in the pharyngeal airway. This dynamic interaction correlates with a reduction in the apnea-hypopnea index (AHI) and Oxygen Desaturation Index (ODI).


Primary site identification in children with obstructive sleep apnea by computational fluid dynamics analysis of the upper airway.

Obstructive sleep apnea (OSA) is a respiratory disorder caused by the obstruction of the upper airway during sleep. The identification of the primary site of OSA is essential to determine treatment strategy. This study aimed to establish computational fluid dynamics (CFD) analysis for determining the clinical severity of OSA and the primary site of OSA. Twenty children (mean age, 6 years) were divided into OSA and control groups according to their apnea-hypopnea index. Three-dimensional airways were constructed from computed tomography data. The pharyngeal airway morphology and the pressure and velocity of the upper airway were evaluated using CFD analysis. The maximum velocity and negative pressure of the upper airway in the OSA group were significantly correlated with the severity of OSA (r = .741, P < .001; r = -.653, P = .002). A velocity higher than 12 m/s indicated the primary site of OSA. In addition, we found that the primary site of OSA is not necessarily the same as the collapsible conduit site. CFD analysis allows both the evaluation of the disease severity of OSA and the identification of the primary site of OSA in children. The primary site of OSA is not necessarily the same as the collapsible conduit site; therefore, CFD analysis can be used to identify the appropriate intervention for treating OSA.


The Effect of Cranial Change on Oropharyngeal Airway and Breathing During Sleep

Mandibular micrognathia is one of the characteristics of obstructive sleep apnea syndrome. The purpose of this study was to assess the effects of bimaxillary surgery without maxillary advancement on the upper airway using computational fluid dynamics (CFD) results of comparing pre- and post-operative finite element model. Seven female patients with jaw deformity, who underwent two-jaw surgery (Le Fort1 osteotomy and bilateral sagittal split ramus osteotomy; BSSRO) were enrolled. Maxillary was moved for correcting occlusal plane and mandibular was moved to advancement. Pharyngeal airway space and breathing during sleep were evaluated, comparing the periods of 2 days before and 6 months after the operation. The cross-sectional area of the level of the hard palate (HP) and the level of the tip of the uvula (TU), and airway volume of total, HP-TU, and TP- the level of the base of the epiglottis (BE) were increased. AI and AHI in 2 days before and 6 months after were decreased. As the result of nasal ventilation condition, velocity of HP and TU in 2 days before and 6 months after were decreased. We think that it was revealed that movement of the maxilla without advancement did not affect to the morphology and function of airway.


Comparison of dynamic occlusal contacts during chewing between children with primary dentition and normal adult females


Relationships among tongue volume, hyoid position, airway volume and maxillofacial form in paediatric patients with Class-I, Class-II and Class-III malocclusions.

To clarify the associations among tongue volume, hyoid position, airway volume and maxillofacial form using cone beam computed tomography (CBCT) data for children with Class-I, Class-II and Class-III malocclusion. Sixty children (mean age, 9.2 years) divided into Class-I, Class-II and Class-III malocclusion groups according to the A-nasion-B angle. Cone beam computed tomography was used for three-dimensional reconstruction of the maxillofacial region and airway. The hyoid position and the tongue, airway and oral cavity volumes were evaluated. Upper airway ventilation status was calculated using computational fluid dynamics. The groups were compared using analysis of variance and Kruskal-Wallis tests; relationships among the parameters were assessed using Pearson's and Spearman's rank correlation tests. The tongue volume was larger in Class-III patients (50.63 cm ) than in Class-I patients (44.24 cm ; P < 0.05). The hyoid position was lower (49.44 cm), and anatomical balance (AB; tongue volume/oral cavity volume; 85.06%) was greater in Class-II patients than in Class-I patients (46.06 cm, 80.57%, respectively; P < 0.05 for both). The hyoid height showed a positive correlation with AB (r = 0.614; P < 0.001). Children with Class-III malocclusion have large tongue volumes and small AB; the reverse is true for children with Class-II malocclusion. The hyoid position is closely associated with AB in children with malocclusion.


Upper airway in children with unilateral cleft lip and palate evaluated with computational fluid dynamics.

Children with unilateral cleft lip and palate (UCLP) exhibit snoring and mouth breathing. They are also reported to show obstructive sleep apnea syndrome. However, their upper airway ventilation condition is not clearly understood. Therefore, this study was performed to evaluate upper airway ventilation condition in children with UCLP with the use of computational fluid dynamics. Twenty-one children (12 boys, 9 girls; mean age 9.1 years) with UCLP and 25 children (13 boys, 12 girls; mean age 9.2 years) without UCLP who required orthodontic treatment underwent cone-beam computed tomography (CBCT). Nasal resistance and upper airway ventilation condition were evaluated with the use of computational fluid dynamics from CBCT data. The groups were compared with the use of Mann-Whitney U tests and Student t tests. Nasal resistance of the UCLP group (0.97 Pa/cm/s) was significantly higher than that of the control group (0.26 Pa/cm/s; P < 0.001). Maximal pressure of the upper airway (335.02 Pa) was significantly higher in the UCLP group than in the control group (67.57 Pa; P < 0.001). Pharyngeal airway (from choanae to base of epiglottis) pressure in the UCLP group (140.46 Pa) was significantly higher than in the control group (15.92 Pa; P < 0.02). Upper airway obstruction in children with UCLP resulted from both nasal and pharyngeal airway effects.

American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO)


Rapid maxillary expansion effects of nasal airway in children with cleft lip and palate using computational fluid dynamics.

Rapid maxillary expansion (RME) improves nasal airway ventilation in non-cleft palate children. Children with unilateral cleft lip and palate (UCLP) may have nasal obstruction and experience an increased risk of obstructive sleep apnoea. The effect of RME in UCLP children is unclear. This retrospective study evaluated RME-induced changes in ventilation parameters in children with UCLP using computational fluid dynamics. Nineteen patients (10 boys, mean age 10.7 years) who required RME had cone-beam computed tomography images taken before and after RME. Twenty control participants (11 boys, mean age 11.1 years) received regular orthodontic treatment. Nasal airway ventilation parameters (air pressure, air velocity and airflow rate) were analysed via computational fluid dynamics, and nasal cross-sectional area (CSA) was measured. Maximum pressure, velocity and nasal resistance were significantly reduced by RME in the UCLP group. Air flow rate and CSA on the cleft side significantly were increased by RME in the UCLP group. In children with UCLP, increasing the quantity of airflow and CSA on the cleft side by RME substantially improved nasal ventilation.


Evaluation of the effect of oral appliance treatment on upper-airway ventilation conditions in obstructive sleep apnea using computational fluid dynamics.

To evaluate the effect of oral appliance (OA) treatment on upper-airway ventilation conditions in patients with obstructive sleep apnea (OSA) using computational fluid dynamics (CFD). Fifteen patients received OA treatment and underwent polysomnography (PSG) and computed tomography (CT). CT data were used to reconstruct three-dimensional models of nasal and pharyngeal airways. Airflow velocity and airway pressure measurements at inspiration were simulated using CFD. The apnea-hypopnea index (AHI) improved from 23.1 to 10.1 events/h after OA treatment. On CFD analysis, airflow velocity decreased at the retropalatal and epiglottis-tip levels, while airway pressure decreased at the retropalatal, uvular- and epiglottis-tip levels. The AHI of patients with OSA before OA treatment was correlated with airway pressure at the epiglottis-tip level. Treatment with OA improved the ventilation conditions of the pharyngeal airway and AHI. Results of CFD analysis of airway pressure and airflow velocity helped determine the severity and ventilatory impairment site of OSA, respectively.


Evaluation of the pharyngeal airway using computational fluid dynamics in patients with acromegaly.

Perioperative airway management may be particularly challenging in patients with acromegaly undergoing trans-sphenoidal pituitary surgery (TSS). Management for airway obstruction is required prior to pituitary surgery to minimize perioperative hypoxia. The purpose of this retrospective study was to evaluate airway obstruction by simulation of computational fluid dynamics (CFD) using computed tomography (CT) images in patients who had undergone TSS. CT images of the nasopharyngeal airways of patients with acromegaly (n = 5) or nonfunctional pituitary adenoma (n = 6) undergoing TSS from April 2012 to January 2017 were used to construct these airways in three dimensions. Estimated airflow pressure and velocity in the retropalatal airway (RA), oropharyngeal airway (OA), and hypopharyngeal airway (HA) were simulated using CFD. Estimated pharyngeal airflow pressure in the HA, OA, and RA was significantly greater in patients with acromegaly than in those with nonfunctional pituitary adenomas whereas the estimated pharyngeal airflow velocity was significantly impaired only in the RA of patients with acromegaly. Minimum postoperative SpO both within 3 hours and from 3 to 12 hours after the end of anesthesia was significantly lower in the patients with acromegaly. Additionally, estimated volume of tongue and pharyngeal airflow pressure in the HA, OA, and RA correlated with minimum postoperative SpO. Pharyngeal airflow pressure estimated from CT images is high in patients with acromegaly, and these values correlate with postoperative minimum values for SpO. Preoperative evaluation of CT images by CFD can predict difficulty in airway management and perioperative hypoxia. 4.


Survey Regarding Effects of Mouth Breathing in Children on Sleep and Daytime Activities

小児の口呼吸が睡眠ならびに日中の行動におよぼす影響のアンケート調査

We conducted a survey to examine the effects of mouth breathing in children on sleep and daytime activities. There were 165 subjects aged 3 to 12 years (73 boys, 92 girls ;mean age 8.3±2.3 years) without a significant medical history who were examined at dental clinics in Kagoshima Prefecture,Japan, in July and August 2017. We found that 27.3% snored and 2.4% stopped breathing during sleep, while mouth breathing was observed in 16.4%. Children who exhibited mouth breathing also showed chest retraction, open mouth during sleep, snoring, difficulty with waking, history of common colds, a runny nose, dysphagia, daytime somnolence, attention deficit, and hyperactivity. We consider that our findings indicate that mouth breathing has major effects on sleep and daily activities of chil dren. Pediatric dentists seek to contribute to the healthy growth and development of children by care for their oral cavity. In addition to addressing morphological and functional problems, such as caries, hard -tissue disease, maxillofacial, dentition and occlusion disorders, and mastication and swallowing disorders, the present results show the importance of providing sufficient attention to potential respira tory disorders.

本研究は小児の口呼吸が睡眠や日中の行動におよぼす影響を明らかにすることを目的に，アンケート調査を行った．2017年7月と8月に鹿児島県内の歯科医院を受診した特記すべき既往のない3歳から12歳までの小児165名(男児73名，女児92名，平均年齢8.3±2.3歳)を対象とした．睡眠中にいびきをかく頻度は27.3%，息が止まる頻度は2.4%だった．口呼吸の頻度は16.4%で，口呼吸を認める場合，胸郭陥凹，開口，鼾，起床困難，風邪，鼻水，嚥下困難，日中傾眠，注意欠陥，多動を示し，小児の口呼吸は睡眠や日常生活に大きな影響をおよぼすことが示された．以上のことから，われわれ小児歯科医が小児の口腔を通した健全な成長発達に貢献するためには，齲蝕をはじめとする硬組織疾患，顎顔面歯列咬合異常や摂食・咀嚼・嚥下障害などの形態的・機能的な問題点に加えて，呼吸に関しても十分な注意を払う必要があることが示された．

The Japanese Journal of Pediatric Dentistry


Comparison of dynamic occlusal contacts during chewing between working and balancing sides


Relationships among nasal resistance, adenoids, tonsils, and tongue posture and maxillofacial form in Class II and Class III children.

The purpose of this study was to clarify the relationships between upper airway factors (nasal resistance, adenoids, tonsils, and tongue posture) and maxillofacial forms in Class II and III children. Sixty-four subjects (mean age, 9.3 years) with malocclusion were divided into Class II and Class III groups by ANB angles. Nasal resistance was calculated using computational fluid dynamics from cone-beam computed tomography data. Adenoids, tonsils, and tongue posture were evaluated in the cone-beam computed tomography images. The groups were compared using Mann-Whitney U tests and Student t tests. The Spearman rank correlations test assessed the relationships between the upper airway factors and maxillofacial form. Nasal resistance of the Class II group was significantly larger than that of the Class III group (P = 0.005). Nasal resistance of the Class II group was significantly correlated with inferior tongue posture (P <0.001) and negatively correlated with intermolar width (P = 0.028). Tonsil size of the Class III group was significantly correlated with anterior tongue posture (P <0.001) and mandibular incisor anterior position (P = 0.007). Anterior tongue posture of the Class III group was significantly correlated with mandibular protrusion. The relationships of upper airway factors differ between Class II and Class III children.


Influence of pharyngeal airway respiration pressure on Class II mandibular retrusion in children: A computational fluid dynamics study of inspiration and expiration.

To examine the influence of negative pressure of the pharyngeal airway on mandibular retraction during inspiration in children with nasal obstruction using the computational fluid dynamics (CFD) method. Sixty-two children were divided into Classes I, II (mandibular retrusion) and III (mandibular protrusion) malocclusion groups. Cone-beam computed tomography data were used to reconstruct three-dimensional shapes of the nasal and pharyngeal airways. Airflow pressure was simulated using CFD to calculate nasal resistance and pharyngeal airway pressure during inspiration and expiration. Nasal resistance of the Class II group was significantly higher than that of the other two groups, and oropharyngeal airway inspiration pressure in the Class II (-247.64 Pa) group was larger than that in the Class I (-43.51 Pa) and Class III (-31.81 Pa) groups (P<.001). The oropharyngeal airway inspiration-expiration pressure difference in the Class II (-27.38 Pa) group was larger than that in the Class I (-5.17 Pa) and Class III (0.68 Pa) groups (P=.006). Large negative inspiratory pharyngeal airway pressure due to nasal obstruction in children with Class II malocclusion may be related to their retrognathia.


Herbst appliance effects on pharyngeal airway ventilation evaluated using computational fluid dynamics.

To evaluate the effect of a Herbst appliance on ventilation of the pharyngeal airway (PA) using computational fluid dynamics (CFD). Twenty-one Class II patients (10 boys; mean age, 11.7 years) who required Herbst therapy with edgewise treatment underwent cone-beam computed tomography (CBCT) before and after treatment. Nineteen Class I control patients (8 boys; mean age, 11.9 years) received edgewise treatment alone. The pressure and velocity of the PA were compared between the groups using CFD based on three-dimensional CBCT images of the PA. The change in oropharyngeal airway velocity in the Herbst group (1.95 m/s) was significantly larger than that in the control group (0.67 m/s). Similarly, the decrease in laryngopharyngeal airway velocity in the Herbst group (1.37 m/s) was significantly larger than that in the control group (0.57 m/s). The Herbst appliance improves ventilation of the oropharyngeal and laryngopharyngeal airways. These results may provide a useful assessment of obstructive sleep apnea treatment during growth.


Simultaneous Evaluation of Three-Dimensional Lip Kinetics and Tongue Pressure during Swallowing

Objectives: The purpose of this study was to evaluate the amount of lip movement and simultaneous tongue pressure changes on an artificial palatal plate during swallowing. Methods: Subjects were 9 healthy males (25.4 ± 2.1 years of age). Three-dimensional lip movement was measured by a wireless optoelectronic system, and tongue pressure was simultaneously recorded by a sensor sheet attached to the incisive papilla of an artificial palatal plate. Reflective markers were attached to the right and left corners of the mouth to measure the distance between them. All subjects were instructed to swallow 5 mL and 20 mL samples of water at will. The maximum change of distance between the corners of mouth, the maximum tongue pressure, and the time interval between the two maxima (lip-tongue interval) were calculated. Wilcoxon's test was used to detect significant differences in these measurements between the two volumes. Results: Maximum tongue pressure did not differ significantly between swallowed volumes. The maximum change of distance between the corners of mouth was larger and the lip-tongue interval was significantly shorter with the larger volume. Conclusions: We suggest that swallowing a larger volume is accomplished by larger lip movement rather than larger tongue movement. These results indicate that lip movement during swallowing can be evaluated objectively.

International Journal of Dentistry and Oral Health


Efficacy of Maxillomandibular Advancement Examined with Drug-Induced Sleep Endoscopy and Computational Fluid Dynamics Airflow Modeling.

To use drug-induced sedation endoscopy (DISE) and computational fluid dynamics (CFD) modeling to study dynamic airway and airflow changes after maxillomandibular advancement (MMA), and how the changes correlate with surgical success based on polysomnography parameters. Retrospective cohort study. University medical center. DISE was rated with the VOTE (velum, oropharynx, tongue, epiglottis) classification, and CFD was used to model airflow velocity and negative pressure exerted on pharyngeal wall. Changes in VOTE score by site and CFD measurements were correlated with perioperative polysomnography outcomes of apnea-hypopnea index (AHI), apnea index (AI), oxygenation desaturation index (ODI), and lowest oxygen saturation. After MMA, 20 subjects (17 males, 3 females) with a mean age of 44 ± 12 years and body mass index of 27.4 ± 4.6 kg/m(2) showed mean decreases in AHI (53.6 ± 26.6 to 9.5 ± 7.4 events/h) and ODI (38.7 ± 30.3 to 8.1 ± 9.2 events/h; P < .001). Improvement in lateral pharyngeal wall collapse during DISE based on VOTE score correlated with the most decrease in AHI (60.0 ± 25.6 to 7.5 ± 3.4 events/h) and ODI (46.7 ± 29.8 to 5.3 ± 2 events/h; P = .002). CFD modeling showed significant positive Pearson correlations between reduction of retropalatal airflow velocity and AHI (r = 0.617, P = .04) and ODI (r = 0.773, P = .005). AHI and ODI improvement after MMA is best correlated with (1) decreased retropalatal airflow velocity modeled by CFD and (2) increased lateral pharyngeal wall stability based on VOTE scoring from DISE.


Quantitative evaluation of toothbrush and arm-joint motion during tooth brushing.

It is very difficult for dental professionals to objectively assess tooth brushing skill of patients, because an obvious index to assess the brushing motion of patients has not been established. The purpose of this study was to quantitatively evaluate toothbrush and arm-joint motion during tooth brushing. Tooth brushing motion, performed by dental hygienists for 15 s, was captured using a motion-capture system that continuously calculates the three-dimensional coordinates of object's motion relative to the floor. The dental hygienists performed the tooth brushing on the buccal and palatal sides of their right and left upper molars. The frequencies and power spectra of toothbrush motion and joint angles of the shoulder, elbow, and wrist were calculated and analyzed statistically. The frequency of toothbrush motion was higher on the left side (both buccal and palatal areas) than on the right side. There were no significant differences among joint angle frequencies within each brushing area. The inter- and intra-individual variations of the power spectrum of the elbow flexion angle when brushing were smaller than for any of the other angles. This study quantitatively confirmed that dental hygienists have individual distinctive rhythms during tooth brushing. All arm joints moved synchronously during brushing, and tooth brushing motion was controlled by coordinated movement of the joints. The elbow generated an individual's frequency through a stabilizing movement. The shoulder and wrist control the hand motion, and the elbow generates the cyclic rhythm during tooth brushing.


Three-dimensional cone-beam computed tomography analysis of enlargement of the pharyngeal airway by the Herbst appliance.

Pharyngeal airway size is increasingly recognized as an important factor in obstructive sleep apnea. However, few studies have examined the changes of pharyngeal airway form after dental procedures for treating obstructive sleep apnea during growth. The purpose of this study was to evaluate the effect of the Herbst appliance on the 3-dimensional form of the pharyngeal airway using cone-beam computed tomography. Twenty-four Class II subjects (ANB, ≥5°; 11 boys; mean age, 11.6 years) who required Herbst therapy with edgewise treatment had cone-beam computed tomography images taken before and after Herbst treatment. Twenty Class I control subjects (9 boys; mean age, 11.5 years) received edgewise treatment only. The volume, depth, and width of the pharyngeal airway were compared between the groups using measurements from 3-dimensional cone-beam computed tomography images of the entire pharyngeal airway. The increase of the oropharyngeal airway volume in the Herbst group (5000.2 mm(3)) was significantly greater than that of the control group (2451.6 mm(3)). Similarly, the increase of the laryngopharyngeal airway volume in the Herbst group (1941.8 mm(3)) was significantly greater than that of the control group (1060.1 mm(3)). The Herbst appliance enlarges the oropharyngeal and laryngopharyngeal airways. These results may provide a useful assessment of obstructive sleep apnea treatment during growth.

American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO)


Morphological differences of facial soft tissue contours from child to adult of Japanese males: a three-dimensional cross-sectional study.

To evaluate morphological differences of the facial soft tissue surface between male Japanese adults and children. 20 adult Japanese males (average age 28 years) and 20 Japanese boys (average age 5.5 years) with normal occlusion were selected for this study. The images of the subjects' facial surface were obtained with a 3-D laser scanner. To evaluate the three-dimensional morphological differences of the facial soft tissue, we transformed the coordinates of 16 facial landmarks to a new reference plane and compared the adults' and children's facial form drawn to the same scale in the same coordinate system. The morphological difference ratio of the lower facial area was higher than in the upper facial area, and the nose and lower face changed more forward than downward. The morphological difference ratio of the mid face width was smaller than other areas. Our study suggests that the morphological facial soft tissue differences between Japanese adults and children are more forward and downward than laterally, manifesting in a facial form of adults that is deeper and narrow.


Relationship between nasal and skeletal landmarks on lateral cephalograms of adults

The Australian Journal of Forensic Sciences


The effect of rapid maxillary expansion on pharyngeal airway pressure during inspiration evaluated using computational fluid dynamics.

Recent evidence suggests that rapid maxillary expansion (RME) is an effective treatment of obstructive sleep apnea syndrome (OSAS) in children with maxillary constriction. Nonetheless, the effect of RME on pharyngeal airway pressure during inspiration is not clear. The purpose of this retrospective study was to evaluate changes induced by the RME in ventilation conditions using computational fluid dynamics. Twenty-five subjects (14 boys, 11 girls; mean age 9.7 years) who required RME had cone-beam computed tomography (CBCT) images taken before and after the RME. The CBCT data were used to reconstruct 3-dimensional shapes of nasal and pharyngeal airways. Measurement of airflow pressure was simulated using computational fluid dynamics for calculating nasal resistance during exhalation. This value was used to assess maximal negative pressure in the pharyngeal airway during inspiration. Nasal resistance after RME, 0.137 Pa/(cm(3)/s), was significantly lower than that before RME, 0.496 Pa/(cm(3)/s), and the maximal negative pressure in the pharyngeal airway during inspiration was smaller after RME (-48.66 Pa) than before (-124.96 Pa). Pharyngeal airway pressure during inspiration is decreased with the reduction of nasal resistance by the RME. This mechanism may contribute to the alleviation of OSAS in children.

International Journal of Pediatric Otorhinolaryngology


Smoothness of molar movement during gum chewing in children with primary dentition.

The purpose of this study was to test the null hypothesis that molar movement during gum chewing in children with primary dentition is as smooth as in adults. Twenty-two healthy children with primary dentition and 23 healthy adult females participated in this study. Mandibular movement during gum chewing was recorded using an optoelectronic analysis system with six degrees-of-freedom at 100 Hz, and 10 cycles were selected for analysis. Normalized jerk cost (NJC) at the incisors and working and balancing molars were calculated in each phase (i.e., opening, closing and occlusal level phases) for each chewing cycle. The NJC of the working side molar in children was larger than in adults in both the opening and occlusal phases. Inter-individual variances of the NJC in each phase in children and adults were smaller than corresponding intra-individual variances, except for the NJC during the occlusal phase of adults for the working and balancing side molars. The inter- and intra-individual variances of the NJC during the closing phase were the smallest in each phase for both children and adults. This indicates that the jaw movements of children with primary dentition are more variable, less smooth, and faster than that of adults.


Tongue posture improvement and pharyngeal airway enlargement as secondary effects of rapid maxillary expansion: a cone-beam computed tomography study.

Rapid maxillary expansion (RME) is known to improve nasal airway ventilation. Recent evidence suggests that RME is an effective treatment for obstructive sleep apnea in children with maxillary constriction. However, the effect of RME on tongue posture and pharyngeal airway volume in children with nasal airway obstruction is not clear. In this study, we evaluated these effects using cone-beam computed tomography. Twenty-eight treatment subjects (mean age 9.96 ± 1.21 years) who required RME treatment had cone-beam computed tomography images taken before and after RME. Twenty control subjects (mean age 9.68 ± 1.02 years) received regular orthodontic treatment. Nasal airway ventilation was analyzed by using computational fluid dynamics, and intraoral airway (the low tongue space between tongue and palate) and pharyngeal airway volumes were measured. Intraoral airway volume decreased significantly in the RME group from 1212.9 ± 1370.9 mm(3) before RME to 279.7 ± 472.0 mm(3) after RME. Nasal airway ventilation was significantly correlated with intraoral airway volume. The increase of pharyngeal airway volume in the control group (1226.3 ± 1782.5 mm(3)) was only 41% that of the RME group (3015.4 ± 1297.6 mm(3)). In children with nasal obstruction, RME not only reduces nasal obstruction but also raises tongue posture and enlarges the pharyngeal airway.


Improvement of nasal airway ventilation after rapid maxillary expansion evaluated with computational fluid dynamics.

Rapid maxillary expansion is known to improve nasal airway ventilation. However, it is difficult to precisely evaluate this improvement with conventional methods. The purpose of this longitudinal study was to use computational fluid dynamics to estimate the effect of rapid maxillary expansion. Twenty-three subjects (9 boys, 14 girls; mean ages, 9.74 ± 1.29 years before rapid maxillary expansion and 10.87 ± 1.18 years after rapid maxillary expansion) who required rapid maxillary expansion as part of their orthodontic treatment had cone-beam computed tomography images taken before and after rapid maxillary expansion. The computed tomography data were used to reconstruct the 3-dimensional shape of the nasal cavity. Two measures of nasal airflow function (pressure and velocity) were simulated by using computational fluid dynamics. The pressure after rapid maxillary expansion (80.55 Pa) was significantly lower than before rapid maxillary expansion (147.70 Pa), and the velocity after rapid maxillary expansion (9.63 m/sec) was slower than before rapid maxillary expansion (13.46 m/sec). Improvement of nasal airway ventilation by rapid maxillary expansion was detected by computational fluid dynamics.


Association between mouth opening and upper body movement with intake of different-size food pieces during eating.

Head rotation is coordinated with mandibular movement during mouth opening, and the range of head rotation and mouth opening change with food size. However, past research did not include upper body movement, and no reports have related head and mandibular movement during realistic eating. The purpose of this study was to analyse head and mandibular movements with intake of different-sized food pieces during realistic eating. The test food consisted of apple cut into two different cube sizes (10mm and 20mm). Head and mandibular movements of 20 healthy young adults eating the apple pieces were simultaneously recorded in three dimensions by a wireless opto-electronic system. Reflective markers were attached to the upper lip and chin to measure the mouth opening range. Five markers were attached to eyeglasses frames to measure linear motion and rotation of the head. One marker was attached to the jugular notch of the sternum to measure linear motion of the upper body. Linear motion, and the inclination angle of the head and upper body, and mouth opening range were compared during intake of different-sized apple pieces. Mouth opening, head-neck rotation angle and the amount of upper body forward translation and inclination increased with larger apple pieces. However, isolated relative head motion was stabilized. We conclude that upper body forward motion and head-neck rotation assist mouth opening whilst stabilizing head orientation, and that the range of head-neck rotation angle, upper body translation and range of mouth opening change with food size during realistic eating.


Condylar shape in relation to anterior disk displacement in juvenile females

The purpose of the study was to test the hypothesis that condylar shape varies based upon the condition of anterior disk displacement in young adolescent patients with temporomandibular disorder (TMD). The study design consisted of 96 juvenile female patients (aged 9 to 20; 15.1 +/- 2.3 yrs.) with clinical signs and/or symptoms of TMD. Bilateral high-resolution magnetic resonance imaging scans were performed in frontal and horizontal views with the mandible in the closed position. Disk positions were evaluated to classify the patients into three diagnostic groups. The results of the study, using ANOVA and Bonferroni tests, demonstrated significant differences among the groups. The conclusion drawn from the study was that condylar shape and size vary based on anterior disk position in juvenile females with TMD. The study's results suggest that disk displacement results in a smaller condyle.


Evaluation of upper airway obstruction in Class II children with fluid-mechanical simulation.

The purpose of this study was to test the null hypothesis that dolichofacial and brachyfacial children with Class II malocclusion do not differ in upper airway obstruction. Furthermore, the ability of fluid-mechanical simulation to detect airway obstruction within the limitations of simulation was examined. Forty subjects from 7 to 11 years of age with Class II malocclusion participated and were divided into 2 groups, dolichofacial and brachyfacial, based on their Frankfort mandibular plane angles. Cone-beam computed tomography images supplied the shape of the entire airway. Two measures of respiratory function, air velocity and pressure, were simulated by using 3-dimensional images of the airway. The images and simulations were compared between the 2 facial types. The size of the upper airway did not differ statistically between facial types; however, the simulated maximal pressure and velocity of the dolichofacial type were significantly higher than those of the brachyfacial type. Airway obstruction differs with the Frankfort mandibular plane angle, even though the depth and cross-sectional area of the airway do not. The fluid-mechanical simulation system developed in this study detected differences in airway obstruction that were not apparent from morphologic studies.

American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO)


Head motion may help mouth opening in children.

Concomitant head and mandibular movement during jaw function is well known in adults; however, its importance in children has not been studied. The brain attains 85-90% of its adult weight at 5 years of age, though the maximum rate of condylar growth is attained at approximately 14 years of age. These findings suggest that the coordination of the head and mandible may differ between children and adults. This study investigated head and mandibular movements of 19 children with complete primary dentition (average age: 5 years 5 months) and compared their functional integration of jaw and head movements to those of 16 female adults (average age: 20 years 3 months) with permanent dentition. Although the mandibular opening distance was significantly greater in the adults, the magnitude of concomitant head motion was greater in children. The results suggest that head extension in children helps increase the magnitude of mouth opening more than in adult women.


Pharyngeal airway in children with prognathism and normal occlusion.

To test the hypothesis that there is no difference in the pharyngeal airway width and the position of the maxillofacial skeleton between prognathic and normal children. Twenty-five girls with prognathism (mean, 7.9 ± 0.9 years old) and 15 girls with normal occlusion (mean, 8.4 ± 1.5 years) participated in this study. On each girl's lateral cephalogram, the coordinates of all points were marked and systematically digitized using a mechanical three-dimensional digitizing system. An independent-groups t-test was used to detect significant upper and lower pharyngeal width differences between the two groups. Correlations between the horizontal positions of each point and upper and lower pharyngeal widths were examined. Prognathic girls had a significantly wider lower pharyngeal airway compared with those with normal occlusion (P = .01). Furthermore, the horizontal coordinate of Ar was significantly positively correlated with lower pharyngeal airway width in both groups of girls. The hypothesis is rejected. The mandible in prognathic girls tends to be positioned more anteriorly, resulting in a wider lower pharyngeal airway.


A reproducibility method to test lip-closing strength in preschool children.

This cross-sectional study tested the reproducibility of a simple button-pulling system for measuring lip-closing strength in normal preschool children and compared their strength to that of normal adults. The sample consisted of 348 preschool children and 123 adults. Lip-closing strength was measured by inserting a button, fastened to a piece of string, into the vestibule between the incisors and lips with minimal mouth opening. The string was attached to a digital tension gauge and was pulled parallel to the floor. Maximum tension, with three repetitions, was recorded at the instant that the button was pulled out of the mouth. Multilevel statistical models were used to evaluate any differences in contractive muscle strength between age groups and between the genders. The strength in children increased significantly from three years to five years (p<0.01). Gender-related differences were found in adults but not in preschool children. Inter-individual variation at each age was larger than intra-individual variation. Measurement of lip-closing strength by button pulling is highly reproducible in children and has potential clinical and research applications.


Frequency of Congenitally Missing Permanent Teeth in Japanese Children

日本人小児の永久歯先天性欠如に関する疫学調査

Congenitally missing permanent teeth (CMPT) is one of the most frequent anomalies in dentistry. CMPT affects not only the occlusal relationships within the maxilla and mandible, but also the total occlusion. In addition CMPT can lead to future skeletal and facial problems. The purpose of this study was to estimate the nation-wide frequency of (CMPT) in Japanese children. Prior to beginning this epidemiological study, the authors obtained permission for the investigation from the ethics committee of Kagoshima University Graduate School of Medical and Dental Sciences (June 25th, 2007).Seven pediatric clinics at dental colleges or universities and several private pediatric clinics participated in this study. The sample consisted of 15,544 pediatric dental patients (7,502 males and 7,502 females). Data were collected from longitudinal dental X-rays, orthopantomograms, and some dental models to determine CMPT (excluding 3rd molars) within 6 months. All patients were judged to be over 7 years of age if they had all their permanent teeth in the dental films. In cases where it was difficult to judge the kind of tooth or its location, the committee members from all 7 colleges/universities reached a consensus on the number of missing teeth and their locations on a case by case basis.A total of 1,568 subjects (10.09%) were diagnosed with CMPT. Of these, 685 were males (9.13%),and 883 were females (10.98%). Differences between the maxilla and the mandible were seen in 4.37% of males and 7.58% of females. Differences between the right and left sides were seen in 0.11% of males and 0.14% of females. The most common missing tooth was the lower second premolar ; missing in 2.96% of adolescents, 2.64% of males (1.32% both sides) and 3.31% of females (1.72% on the right side and 1.59% on the left side). In descending order the next most common missing teeth were the mandibular lateral incisors, the maxillary second premolars, and the upper lateral incisors.

永久歯の先天性欠如は，その発現部位や欠如歯数によって様々な歯列咬合異常を誘発するため，小児期からの健全な永久歯咬合の育成を目標とした継続的な口腔管理を行う上で大きな問題となる．我が国の先天性欠如の発現頻度の報告は，単一の医療機関を受診した小児患者の資料に基づいたものが多く，被験者数も限られている．そこで，日本小児歯科学会学術委員会の企画で国内の7 大学の小児歯科学講座が中心となり，我が国初の永久歯先天性欠如に関する全国規模の疫学調査を実施した．参加7 大学の代表者と実務者による全体打ち合わせ会を通して，調査方法の規格化や症例の審議を重ね，調査の信頼性向上に努めた．対象者は，大学附属病院の小児歯科，またはこれらの大学の調査協力施設に来院し，エックス線写真撮影時の年齢が7 歳以上であった小児15,544 名(男子7,502 名，女子8,042 名)とした．第三大臼歯を除く永久歯の先天性欠如者数は1,568 名，発現頻度は10.09%であり，男子が9.13%，女子が10.98%であった．上顎では4.37%，下顎では7.58%に認められた．上顎および下顎における左右の頻度の差は0.11%，0.14%であり左右差は小さかった．歯種別では，下顎第二小臼歯に最も多く認められ，次いで下顎側切歯，上顎第二小臼歯，上顎側切歯の順であった．

The Japanese Journal of Pediatric Dentistry


Three-dimensional Analysis of Facial Surface Morphology in Japanese Infant : 2. Dimensional measurements

幼児期の顔面軟組織の三次元形態解析 : 2. 幅径と高径について

The process of facial growth is of interest in dentistry, physical anthropology, and even industry. Several Japanese national institutes, e.g., the Advanced Industrial Science and Technology and the Research Institute of Human Engineering for Quality Life have measured and reported aspects of human body size and shape, including the facial morphology of children and adults. However, the facial morphology of infants was not included in these reports.In this study, three-dimensional facial morphological measurements of infants were performed using a three-dimensional laser surface-scanner system (VIVID 910, KONICA MINOLTA SENCING, Inc. Osaka, Japan). One hundred and twenty normal developing children (20 boys and 20 girls each at 4, 5 and 6 years of age) had their faces scanned by VIVID. Four widths (inter-Exocanthion width,inter-Endocanthion width, inter-Alar crest width and inter-Cheilion width) and 6 heights (Nasal height, upper facial height, mouth height, total facial height, lower facial height and Vermilion height) were measured.Most measurements increased with age in both boys and girls. Although significant sex-related differences were detected among the three age groups, there were no consistent tendencies. The infants'growth rates for the measurements were not the same as those of adults from the literature. [I do not understand the next sentence. Perhaps you mean : "For example, widths in the upper part of the face at four years of age are already 80% that of adults. Most measurements differed significantly between 5 and 6 years of age, but only 2 measurements differed significantly between 4 and 5 years of age. These results suggest that facial growth is not constant between 4 and 6 years of age, with rates affected by both age and sex. Further investigation may be required to elucidate characteristics of facial growth during childhood.

顔面の形態は歯科だけでなく，人体寸法・形状という観点からも関心が持たれている．しかし，小児を対象とした近年の報告は限られており，特に幼児に関する報告は見当たらない．そこで，本研究はレーザー型三次元非接触型デジタイザを用い，鹿児島市のT 保育園・幼稚園に通園する健康な4∼6 歳の幼児(年齢毎に男女各20 名:計120 名)の顔面形態を計測し，成長に伴う変化と性差について横断的検討を行なった．計測項目は幅径として，外眼角幅径，内眼角幅径，鼻翼外側間幅径，口裂幅径の4 個，高径として，鼻部高径，上顔面高径，口裂高径，顔面高径，下顔面高径，赤唇高径の6 個を設定した．全体として，増齢的に幅径・高径が増加する傾向を認めた．しかし，5 歳と6 歳の年齢間には多くの計測項目において有意な差を認めたものの，4 歳と5 歳の年齢間では女児の2 項目だけに有意差を認めたことから，この2 年間においても1 年毎に成長量が異なることが示唆された．幅径の計測項目は，頭蓋に近い，より上方の計測項目ほど成人に近い値を示した．年齢毎に行なった性差の検定では，3 つの年齢における，それぞれ10 個の計測項目，計30 項目の中で5 個の項目において有意差を認めたが，一定の傾向は見られなかった． 以上より，幼児の顔面は全体として成長していく中で，その量は年齢，性別，部位のそれぞれにおいて特徴があることが示唆された．


Oropharyngeal airway in children with Class III malocclusion evaluated by cone-beam computed tomography.

Upper airway size is increasingly recognized as an important factor in malocclusion. However, children with Class III malocclusion are somewhat neglected compared with those with a Class II skeletal pattern. Therefore, the purpose of this study was to establish the characteristic shape of the oropharyngeal airway (OA) in children with Class III malocclusion. The sample comprised 45 children (average age, 8.6 +/- 1.0 years) divided into 2 groups: 25 with Class I and 20 with Class III malocclusions. OA size of each group was evaluated by cone-beam computed tomography. Cluster analysis, based on OA shape, redivided the subjects into wide, square, and long types. The distributions of Class I and Class III subjects were compared among the types. The Class III group showed statistically larger OA area and width compared with the Class I group. Area was positively correlated with Class III severity. The square type included 84% of the Class I malocclusions but only 30% of the Class III malocclusions, indicating that the OA in Class III malocclusion tends to be flat. The Class III malocclusion is associated with a large and flat OA compared with the Class I malocclusion.


Effect of maxillary protrusion on upper airway obstruction in children by fluid-mechanical simulation

上気道流体シミュレーションからみた通気状態が顎顔面形態に及ぼす歯科的影響


A Survey of the Actual Condition in Adolescent Patients with TMJ Dysfunction Syndrome at the Pediatric Dentistry Clinic for 20 years

当科外来における20年間の思春期顎関節症患者の実態調査

We investigated clinical data concerning adolescent patients who were referred to the Pediatric Dentistry CLinic in Kagoshima University Dental Hospital for consultation and treatment of TMJ Dysfunction Syndrome during a period of 20 years, from 1982 to 2001. We also examined the difference between the data obtained during the first 10 years and those obtained during the second 10years. The results are as follows.
1. The number of patients during the second 10 years increased compared with that during the first 10years.
2. The ratio of female patients showed a higher frequency than the ratio of male patients for the 20years. Furthermore, it showed a higher frequency during the second 10 years than during the first 10years.
3. The ratio of pains was higher and the ratio of sounds was lower during the second 10 years than those during the first 10 years in the number of the patients categorized by the chief complaint, the number of initial symptoms felt by patients, and the number of clinical symptoms at the first medical examination.
4. The frequency in the use of occlusal treatment decreased greatly and the frequencies in use of physical therapy and drug therapy increased greatly during the second 10 years compared with during the first 10 years.
5. There was no significant difference in the effect obtained by treatment between during the first 10years and during the second 10 years.

講座開設以来約20年間に,鹿児島大学歯学部附属病院小児歯科外来に来院した思春期の顎関節症患者の実態調査を行い,前半期10年,後半期10年で比較し,検討を行った．
来院患者の実態調査より,来院患者数は前半期に比べ,後半期で増加している．男女比については20年間を通じて女子が男子と比べて,高頻度を示し,後半期では前半期より女子の比率が増加している．主訴別患者数,初発症状,初診時臨床症状についてはいずれも頻度順には変化はないものの,前半期に比べて後半期で,疼痛の割合が増加し,雑音の割合が減少している．
治療の実態調査より,治療法では前半期に比べて後半期に咬合治療の割合が大きく減少し,理学療法,薬物療法はその割合が大きく増加しているものの,治療効果については前半期に比べ,後半期では大きな変化は見られなかった．


Developmental Changes of First Molar Position in Crowding Dentition

叢生者の成長発達に伴う第一大臼歯の移動様相

This study examined changes in angulation and anterior-posterior position of the first molar in crowding dentition. The subjects were divided into four groups depending on their dentition scores at Hellman's dental stage IV A: 1) normal males (n=5),2) males with crowding (n=5),3) normal females (n=5) and 4) females with crowding (n=5). Tooth position was determined by lateral cephalometric X rays taken longitudinally from III A to IV A, and the following results were obtained;
(1) ANS-PNS and Me-Go for both males and females with crowding were smaller than that for normal males and females at all of the dental stages.
(2) The forward displacement of the upper first molar from III A to NA for both males and females with crowding was significantly greater than that for normal males and females.
(3)∠U 6-Pal. Pl. at III A for both males and females with crowding was smaller than that for normal males and females. The increase in ∠U 6-Pal. Pl, from III A to IV A for both males and females with crowding was larger than that for normal males and females.
(4) The forward displacement of the lower first molar from III A to IV A for both males and females with crowding was not significantly different from that for normal males and females. One characteristic of developmental change of the first molar in crowding dentition is that the upper first molar erupts with distal tipping, and subsequently migrates mesially with mesial rotation.

成長発達期における叢生者の第一大臼歯の移動様相を明らかにするため,Hellmanの歯齢IIIAからIVAにかけて経年的に得られた叢生者の側貌頭部エックス線規格写真を用いて,叢生者の第一大臼歯の顎骨に対する前後的位置ならびに歯軸の成長発達に伴う変化を調査し,以下の結論を得た.
1.ANS-PNSとMe-Goについて,IIIA,IVAいずれの時期も男女ともに叢生群は正常群より小さかった.
2.上顎第一大臼歯のIIIAからIV Aまでの前方移動量は男女とも叢生群は正常群より有意に大きかった.
3.IIIAでの∠U6-Pal.Pl.は男女とも叢生群は正常群より小さく,上顎第一大臼歯は遠心に傾斜していた.その後,IIIAからIVAまでの∠U6-Pal.Pl.の変化量は男女とも叢生群は正常群より有意に大きく,上顎第一大臼歯は大きく近心に傾斜した.
4.IIIAからIVAまでの下顎の第一大臼歯の前方移動量は男女とも叢生群と正常群の間に有意差を認めなかった.叢生者の上顎第一大臼歯はIIIAでは正常者より遠心に傾斜して萌出するが,その後歯齢の増加に伴い大きく近心に傾斜し,IVAでは正常者より近心に移動することが示された.


Hellmanの歯齢IICからIVAにおける叢生と咀嚼筋筋電図との関係

Hellmanの歯齢IICからIVAにおける叢生と咀嚼筋筋電図との関係


Hellman歯齢IICからIVAまでの叢生者の顎骨歯槽基底部の成長様相

Hellman歯齢IICからIVAまでの叢生者の顎骨歯槽基底部の成長様相


A Study of the Longitudinal Changes of the Dental Arch Form and Craniofacial Morphology on Subjects with Crowding Permanent dentition

Hellmanの歯齢に基づく叢生歯列者の顎顔面・歯列形態の経年的研究

The purpose of this study was to examine the constituents of crowding permanent dentition by longitudinal changes from stage II C of Hellman's dental age to stage IV A of the dental arch form and craniofacial morphology. The dental arch form was analyzed using dental casts, and the craniofacial morphology was analyzed using the roentgenocephalometric films. The subjects were divided into two groups by the level of arch length discrepancy of permanent dentition at stage IV A of Hellman's dental age. The two groups were classified into the normal dentition group (NDG) and the crowding dentition group (CDG). The NDG was comprised of 15 subjects, and the CDG of 11 subjects. The findings were as follow; 1) The mesio-distal lengths of maxillar or mandibular in the CDG tended to be short in comparison with the length in the NDG after stage III A.2) The axial inclination of the incisor in the CDG tended to be small in comparison with the axial inclination in the NDG after stage III A.3) There was a significant positive correlation between the arch length discrepancy and dental arch width at stage II C. The dental arch length and arch perimeter after stage III A related to the arch length discrepancy with a significant positive correlation. In contrast, there was a significant negative correlation between crown width and arch length discrepancy at stages III A and IV A.

永久歯列における叢生の発生過程について,歯列模型ならびに側貌頭部エックス線規格写真により検討されている．しかし,明確に解決されているとは言えない．本研究は,Hellmanの歯齢に従った経年的歯列模型ならびに,頭部エックス線規格写真の分析から,永久歯列における叢生の成り立ちについて検討した．対象は,経年的資料が得られた男子12名,女子14名の計26名であり,歯列叢生度(Arch Length Discrepancy)により正常歯列群15名と叢生歯列群11名の2群に分け比較し検討した．得られた結果は,以下の通りである．1)叢生歯列群の上下顎骨体はHellmanの歯齢IIIA以後,正常歯列群と比較し,近遠心的に短い傾向にあった．2)叢生歯列群の前歯歯軸傾斜は,Hellmanの歯齢IIIA以後,正常歯列群と比較し,小さい傾向にあった．3)叢生歯列群の歯列形態において,歯列幅径がHellmanの歯齢IICにおいて歯列叢生度と有意に正の相関関係を示し,IIIA以後は,歯列弓長径と歯列弓周長ともに,歯列叢生度と有意に正の相関関係を示した．逆に,歯冠幅径については,歯列叢生度と有意に負の相関関係を示した．以上の所見から,永久歯列における叢生は,少なくともHellmanの歯齢IIIAからすでに,歯列形態にとどまらず顎顔面形態においても,歯列の叢生度と関連する変化が生じていることが示唆された．


A Study on Longitudinal Variation in the Function of Masticatory Muscles of Children with Normal Occlusions and Crowding Dentitions

正常歯列者と叢生者の咀嚼機能の差についての経年的研究

The purpose of this study was to clarify the functional difference of the masticatory muscles between 6 children with normal occlusions and 11 children with crowding dentitions, by investigating the interocclusal points and electromyographs from Hellman's dental stage IIA to IVA.
1) As the stage progressed, it became clear in IIIC and IVA that the number of interocclusal points of the group with crowding dentitions became smaller than that of the normal occlusion group.
2) From the results of the integrated value (the sum of the electric potential (S)S=TA+TP+M) of the electromyographs in the normal occlusion group, the ratio (M/S) of the electric potential in M to the total active potential became larger than that of TA/S, for the period from the IIIA to IIIB stage. In the group with crowding dentitions, however, M/S became larger than that of TA/S, for the period from the IIIB to IIIC stage.
3) The length of all masticatory rhythms (druation, interval and cycle) in the group with crowding dentitions tended to decrease as the dental stage progressed. In the normal occlusion group, however, only the duraticn tended to decrease as the dental stagc progressed. All masticatory rhythms of children with crowding dentitions were longer than in the normal occlusion group for all the stages.
4) The masticatory rhythms of the masseter muscle obtained by gum chewing tended to stabilize as the dental stage progressed in the both groups. The rhythms were more stable in the normal occlusion group than in the group with crowding dentitions for all the stages.
5) The frequency of the occurrence of the silent period in the group with crowding dentitions was lower in comparison with that of the normal occlusion group in the IIIB, IIIC and IVA stage. The duration of the silent period in the group with crowding dentitions was longer than that of in the normal occlusion group.
Based on the above-mentioned results, it is suggested that the developmental characteristics of the masticatory function in cases with crowding dentitions is retarded, compared with that in cases with the group with the normal occlusions.

叢生者の咀嚼機能の発育様相を明らかにする目的で,経年的に得られた咀嚼筋筋電図を用いて正常歯列者群と叢生歯列者群の比較を行った.
叢生歯列者群の筋電図積分値は,側頭筋優位から咬筋優位になるのが正常歯列老群より遅れた.
叢生歯列者群の咀嚼リズムの長さは歯牙年齢の進行に伴い短縮傾向を示したが,正常歯列者群より長かった.また,叢生歯列者群は歯牙年齢の進行に伴い咀嚼リズムは安定してきたが,正常歯列者群より不安定だった.
叢生歯列者群のsilent period出現頻度は,IVAで90%に達せず,正常歯列者群より低かった.また,叢生歯列者群のsilent period durationは歯牙年齢の進行に伴い短縮したが,正常歯列者群よりIIA-IIIB間で長かった.
以上のことから,叢生歯列者の咀嚼機能の発育様相は正常歯列者と同様の様相を示すものの,正常歯列者より遅延する事が示唆された.


American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO)