Narrow Maxillary Arch Research Articles

Palatal Morphology After Treatment of Children With Obstructive Sleep Apnoea Using the Modified Twin-Block Appliance

ObjectiveTo investigate changes in the upper maxillary palates of children with obstructive sleep apnoea (OSA) and mandibular retraction who were treated using modified twin-block appliances (MTBAs). MethodsThirty-five OSA children (age: 6-12 years) with mandibular retraction were included as the experimental group and 35 children who were Angle's class I but without mandibular retraction were included as the control group. The experimental group was treated with MTBA. Plaster models were made before the treatment and at the end of the 6-month treatment period. Plaster models of the control group were made at inclusion and after 6 months. Some plaster models were excluded because of damage or their failure to exhibit sufficiently clear marks, which left 26 pairs each for the experimental and control groups. The gender and age of the experimental group were matched with those of the control group at the end of the treatment. Three-dimensional (3D) digital model information was gathered using the external oral scanning model, and the data were extracted and analysed statistically to clarify the morphologic improvement in the maxillopalatine in OSA children treated using MTBAs. ResultsAfter the OSA children with mandibular retraction were treated with MTBAs, the maxillary intercusp width, intermolar width, anterior palate width, posterior palate width, and surface area and volume of the maxillary palate significantly increased (*P < .05). By contrast, the anterior palatal height–apex level (H3) significantly decreased (*P < .05). ConclusionsCompared with the control group, the narrow maxillary arch and basal bone were significantly enlarged after the OSA children with mandibular retraction were treated using MTBAs. The palatal surface area and volume increased, thereby allowing more space for accommodating the tongue and relieving transverse dissonance of the dentition.

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

This study aimed to clarify the effect of palatine tonsil hypertrophy-induced ventilation obstruction on maxillofacial dentition morphology using computational fluid dynamics (CFD) to represent tongue posture and maxillofacial dentition three dimensionally. We analyzed data of 20 patients with tonsil hypertrophy (tonsil hypertrophy group (TG); 9.0 years old, seven boys) and a comparison group (CG) of 20 patients without tonsil hyperplasia (comparison group; 9.4 years old, 10 boys). Cone-beam computed tomography and CFD data were used to assess the effects of palatine tonsil hypertrophy on pharyngeal airway ventilation, tongue posture, and morphology of the maxillofacial dentition. The TG exhibited significantly greater depth, narrower width, smaller cross-sectional area of the pharyngeal airway, and narrower maxillary dental arch with Class II than the CG. Additionally, the tongue was positioned significantly more anteriorly and inferiorly in the TG than that in the CG. Our data suggest that hypertrophy of the palatine tonsils narrows the pharyngeal airway, resulting in a smaller cross-sectional area. Widening of the pharyngeal airway may occur due to compensatory anterior displacement of the tongue to prevent ventilation obstruction. This may decrease palatal support, disturbing the pressure balance of the maxillary molar region between the buccal and palatal sides and resulting in lateral undergrowth of the maxillary bone and narrowing of the maxillary dental arch.

Maxillary Expansion and Its Effects on Circummaxillary Structures: A Review.

Transverse maxillary discrepancies are the most common. The narrowed upper arch is the most prevalent problem an orthodontist encounter while treating adolescent and adult patients.Maxillary expansion is a technique used to increase the upper arch's transverse dimension to apply forces to widen the upper arch. For young children, a narrow maxillary arch has to be corrected using orthopedic and orthodontic treatments. In an orthodontic treatment plan, it is crucial to update transverse maxillary defeat. There are various clinical manifestations associated with a transverse maxillary deficiency which include a narrow palate, crossbite mainly seen in posteriors (unilateral or bilateral), severe crowding in anterior teeth, and cone-shaped hypertrophy can be seen. Some frequently used therapies for constricted upper arch include slow maxillary expansion, rapid maxillary expansion, and surgically assisted rapid maxillary expansion. Slow maxillary expansion requires light and constant force, whereas rapid maxillary expansion needs heavy pressure for activation. The surgical-assisted rapid maxillary expansion has gradually become popular to correct transverse maxillary hypoplasia. The maxillary expansion has various consequences on the nasomaxillary complex. There are multiple effects of maxillary expansion on the nasomaxillary complex. Mainly, the effect is seen on the mid-palatine suture along with the palate, maxilla, mandible, temporomandibular joint, soft tissue, and anterior and posterior upper teeth. It also affects functions like speech and hearing. Information on maxillary expansion is provided in depth in the following review article, along with its various effects on the surrounding structure.

A comparison of the quadhelix and the nickel-titanium palatal expander in the treatment of narrow maxillary arches: A prospective clinical study

The study aimed to compare the effects of quadhelix and nickel-titanium (NiTi) expander appliances on lower facial height, to quantify, and evaluate dentoalveolar and orthopedic changes in transverse plane, respectively, to estimate the difference in changes between these two appliances.Twenty patients, ten for the quadhelix and NiTi expander in the two-appliance group, respectively, participated in this study. A total of 8 readings, 1 for clinical facial height, 2 for model analysis, and 5 for posteroanterior cephalometric analysis were recorded. The statistical tests used were, Student's unpaired and paired t-tests.Both appliances individually, produced statistically highly significant (p < 0.01) expansion every month in both premolar and molar areas with more uniform expansion for quadhelix and less expansion in NiTi palatal expander in the premolar region initially. The skeletal to dental change ratio showed that there was more dental change than skeletal with no inter-appliance differences statistically while assessing the PA cephalometric readings.This study infers that both appliances are equally efficacious maxillary expanders, which are primarily dentoalveolar and not skeletal (p < 0.05).

Temporomandibular Joint Disorder and Airway in Class II Malocclusion: A Review.

In class II malocclusion, there is an anteroposterior disparity between the upper dentition and the lower dentition, which may or may not be accompanied by a skeletal discrepancy. For orthodontists, this is one of the common malocclusions encountered during clinical practice. This might be due to excess maxillary growth or retarded growth of the mandible or a combination of both. In such types of malocclusion, both the upper and lower airways are affected, the lower one most commonly. Characteristic features seen are a narrow maxillary arch, a proclined upper anterior, and mouth breathing as a developing habit. Also, the position of the condyle in the skeletal type of class II malocclusion plays a vital role in the development of temporomandibular joint disorders. Treating such disparity in a growing individual leads to better results in the long term as well as prevention of malocclusion taking a severe form. Myofunctional appliances are useful for repositioning the mandible as well as the condyle. In adults, extraction of the upper premolars is most commonly done for the correction of class II malocclusion. This provides the patient with a better esthetic appearance.In addition to this, various treatment modalities, such as splint therapy, exercise, and prolotherapy, are beneficial for pain relief and temporomandibular disorder (TMD) correction. This article deals with the characteristics, development, etiology, and comprehensive treatment options of class II malocclusion and its co-relation with the upper and lower airway along with the severity of temporomandibular joint disorders. Repositioning of the condyle in the glenoid fossae is the key to the correction of this disorder.

Evaluation of successful treatment of patients with unilateral functional crossbite

Purpose: Unilateral functional crossbite (UFCB) is one of the most common malocclusions in the deciduous and early mixed dentition stage. It is accompanied by lateral mandibular shift and mandibular midline deviation due to the narrow maxillary dental arch. The aim of this study was to assess the effects of early correction of UFCB with the Fränkel (FR–3) functional regulator.&#x0D; Methods: Ninety Caucasian subjects (32 boys and 58 girls) with UFCB in the early mixed dentition stage (mean age, 6 years and 8 months (SD±1.8)) were treated with the FR–3 functional regulator and monitored. The diagnosis was based on anamnestic data, clinical examinations, radiographs, and analyses of study cast models. Dental casts taken before and after treatment were used in the analysis of effects.&#x0D; Results: Treatment of UFCB involved expansion of the maxillary arch, removal of occlusal interferences, and elimination of the functional shift. The width of the maxilla increased by 2.90 mm (SD±1.63) in the canine region and by 2.78 mm (SD±1.60) in the molar region. Another advantage of early treatment was improvement of maxillary arch length deficiency secondary to maxillary constriction because the permanent incisors were afforded more space before or during eruption than if the crossbite was treated at a later age. At least one abnormal orofacial function was identified in 69 (76,67%) patients with UFCB. Aftertreatment, all crossbites were corrected, functional deviations were eliminated, and no relapses were observed during follow–up at 2 years and 8 months.&#x0D; Conclusion: The Fränkel functional regulator is a functional orthodontic–orthopedic device that is an effective alternative for the treatment of UFCB. Dental occlusion was significantly improved, and the prognosis for normal craniofacial growth and normal function of the stomatognathic system was enhanced.

Dysphagia in a persistently vegetative patient improved by orthodontic treatment of severe dental misalignment

We describe the treatment of severe dysphagia in a patient left in a persistent vegetative state after an episode of hypoxic-ischemic encephalopathy following a traffic accident. A 38-year-old man was in a persistent vegetative state since a traffic accident in 2005, which resulted in cardiopulmonary arrest and hypoxic-ischemic encephalopathy. His airway had been secured with a tracheostomy, and a gastric tube had been inserted; however, he continued to suffer from urinary tract infections, glossoptosis, and silent aspiration of saliva. Both the maxilla and mandible had very narrow dental arches, with the mandibular incisors exhibiting severe lingual inclination. We first corrected the dentition in the narrow maxillary arch, followed by the mandibular arch. As the dental alignment improved, tongue movements appeared during oral care, and endoscopy also revealed signs of an active saliva swallowing reflex. The "training approach" generally used to treat severe dysphagia is usually impossible in persistently vegetative patients. In our patient, the tongue movements and saliva swallowing reflex appeared after we expanded the narrow dental arches, suggesting that an orthodontic approach can be effective in such cases. Our findings can be applied to similar cases of vegetative patients to facilitate better oral care and outcomes.

Efficacy of Rapid Maxillary Expansion with or without Previous Adenotonsillectomy for Pediatric Obstructive Sleep Apnea Syndrome Based on Polysomnographic Data: A Systematic Review and Meta-Analysis

Aim: To systematically review international literature related to rapid maxillary expansion (RME) as the treatment for obstructive sleep apnea syndrome (OSAS) in children less than 18 years-old, followed by a meta-analysis of the apnea-hypopnea index (AHI) before and after RME, with or without a previous adenotonsillectomy (AT). Methods: Literature on databases from PubMed, Wiley online library, Cochrane Clinical Trials Register, Springer link, and Science Direct were analyzed up to March 2020. Two independent reviewers (S.G. and R.J.M.) screened, assessed, and extracted the quality of the publications. A meta-analysis was performed to compare AHI values before and after the treatment with RME. Results: Six studies reported outcomes for 102 children with a narrow maxillary arch suffering from OSAS with a mean age of 6.7 ± 1.3. AHI improved from a M ± SD of 7.5 ± 3.2/h to 2.5 ± 2.6/h. A higher AHI change in patients with no tonsils (83.4%) and small tonsils (97.7%) was detected when compared to children with large tonsils (56.4%). Data was analyzed based on a follow-up duration of ≤3 year in 79 children and &gt;3 years in 23 children. Conclusion: Reduction in the AHI was detected in all 102 children with OSAS that underwent RME treatment, with or without an adenotonsillectomy. Additionally, a larger reduction in the AHI was observed in children with small tonsils or no tonsils. A general improvement on the daytime and nighttime symptoms of OSAS after RME therapy was noted in all the studies, demonstrating the efficacy of this therapy.

Inter-premolar width changes related to the orthodontic traction of maxillary impacted canines in adolescents and young adults: A retrospective CBCT study

Maxillary canine impaction is directly associated with a narrow maxillary arch, mainly in the inter-premolar widths. This study compared the transverse changes at the level of maxillary premolars after traction of maxillary impacted canines (MICs) in adolescents and young adults through three main goals: to compare unilateral versus bilateral cases, to compare buccally versus palatally MIC cases, and to compare the affected versus non-affected side exclusively in the unilateral group. This before and after CBCT study involved 45 MIC orthodontically tractioned until the occlusal plane with a standardized protocol. The sample was classified regarding the impaction type (unilateral versus bilateral), impaction location (palatal versus buccal) and the affected versus unaffected sides in the unilateral cases. MIC characteristics as impaction sector, height, and complexity of the traction, as well as α and β angles, canine root length and area were measured. Moreover, cephalometric characteristics were also evaluated. Mann-Whitney U or Wilcoxon signed-rank tests and multiple regressions were applied (α=0.05). Maxillary inter-premolar widths (first or second) expanded approximately 3mm after traction of unilateral or bilateral MIC (P>0.05). Changes in hemi-arch widths between palatal (1.67mm) versus buccal (1.90mm) MIC were similar (P>0.05). In unilateral impaction, the transversal changes on the affected side were 2mm versus almost 1mm observed in the unaffected side (P<0.05). Finally, the multiple linear regressions were identified to the ANB angle, the impaction sectors and the distance from middle raphe to the cusp tip of MIC as influential variables. The maxillary inter-premolar widths increase after traction of MIC without differences between type or location of impaction. In addition, the transverse change in the affected side in unilateral MIC is greater than the unaffected side resolving the earlier transverse asymmetry.

Effects of maxillary expansion on hearing and voice function in non-cleft lip palate and cleft lip palate patients with transverse maxillary deficiency: a multicentric randomized controlled trial

IntroductionThe association between the treatment of transverse maxillary deficiency and the recovery of hearing and voice functions has gained attention in recent years. ObjectiveThis prospective controlled trial aimed to evaluate the effects of rapid maxillary expansion on hearing and voice function in children with non-cleft lip palate and bilateral cleft lip palate with transverse maxillary deficiency Methods53 patients (26 non-cleft and 27 bilateral cleft lip palate; mean age, 11.1±1.8 years) requiring rapid maxillary expansion for correction of narrow maxillary arches were recruited for this trial. Eight sub-groups were established based on the degree of hearing loss. Pure-tone audiometric and tympanometric records were taken for each subject at four different time periods. The first records were taken before rapid maxillary expansion (T0), the second after expansion (T1) (mean, 0.8 months), the third after three months (T2) (mean, 3 months) and the fourth at the end of retention period (T3) (mean, 6 months). ANOVA and Tukey HSD post-hoc tests were used for data analysis. Additionally, voice analysis was done using an updated PRAAT software program in a computerized speech lab at T0 and T2. A paired-samplet-test was used for comparisons of mean values of T0 and T2 voice parameters within both groups. ResultsRapid maxillary expansion treatment produced a significant increase in the hearing levels and middle ear volumes of all non-cleft and bilateral cleft lip palate patients with normal hearing levels and with mild conductive hearing loss, during the T0–T1, T1–T2, T0–T2, and T0–T3 observation periods (p<0.05). The significant increase was observed in right middle ear volumes during the T0–T1, T0–T2 and T0–T3 periods in non-cleft patients with moderate hearing loss. For voice analysis, significant differences were observed only between the T0 and T2 mean fundamental frequency (F0) and jitter percentage (p<0.05) in the non-cleft group. In the cleft group, no significant differences were observed for any voice parameter between the T0 and T2 periods. ConclusionCorrection of the palatal anatomy by rapid maxillary expansion therapy has a beneficial effect on both improvements in hearing and normal function of the middle ear in both non-cleft and bilateral cleft lip palate patients. Similarly, rapid maxillary expansion significantly influences voice quality in non-cleft patients, with no significant effect in BCLP patients.

Differences in dentofacial morphology in children with sleep disordered breathing are detected with routine orthodontic records

BackgroundResidual snoring in children with obstructive sleep disordered breathing (SDB) may continue post-adenotonsillectomy. This study aims to identify baseline dentofacial differences in children with SDB using routine orthodontic records that might aid effective early intervention for the upper airway to prevent continued obstruction. MethodsChildren (6–16 years) with clinically diagnosed SDB from a paediatric Otolaryngology Clinic who required adenotonsillectomy were participants (n = 10). The control group (n = 9) comprised healthy non-snoring children from the community. Baseline overnight polysomnography (PSG), standardised frontal and right profile photographs and alginate impressions were taken of all children. Facial width, length, depth, convexity and mandibular position were measured from the photographs. The occlusion, arch width, arch depth, maxillary arch form, palatal height and volume were recorded from digitised dental models. Inter-group differences were compared. ResultsSDB patients had a significantly increased lower face height, maxillo-mandibular angle (1.73°; 95% CI 0.45–3.0) and a narrower maxillary arch in the upper posterior region. There was a trend towards a decreased palatal volume, increased posterior crossbite and Class II molar relationship. ConclusionDentofacial phenotypic differences between children with SDB and controls can be detected using facial photographs and dental models. Increased awareness of these features may help to identify children who to continue to snore post adenotonsillectomy.

Comparison of intercanine width in between Angle class II division 1 and division 2 malocclusions

Introduction: Dental arch width measurement is needed to determine diagnoses and orthodontic treatment planning of Angle Class II Division 1 and Class II Division 2 malocclusions that have narrow maxillary dental arch generally. Dental arch width in this study was measured by maxillary and mandibular intercanine width. This study aimed to compare the differences of intercanine width between Angle Class II division 1 and Class II division 2 malocclusions. Methods: Descriptive comparative research with total samples of 67 study models, consisted of 34 Class II division 1 cases and 33 Class II division 2 cases. The minimum age of the samples chosen was 13 years old with no history of orthodontic treatment. A non probability consecutive sampling technique was used. Results: Study results showed the avarage maxillary and mandibular intercanine width of Class II Division 1 were 33,99 mm and 26,33 mm. Average maxillary and mandibular intercanine width of Class II Division 2 were 34,77 mm and 25,37 mm. Conclusions: T-test analysis showed no statistical significant differences in the intercanine width between Angle Class II Division 1 and Class II Division 2 malocclusions.

Does rapid maxillary expansion affect nasopharyngeal airway? A prospective Cone Beam Computerised Tomography (CBCT) based study

Background and purposeThere is limited literature discussing the three dimnesional (3D) impact of rapid maxillary expansion (RME) on upper airway. The purpose of this prospective Cone Beam Computerised Tomography (CBCT) based study is to assess the immediate 3D effects and to correlate the volumteric changes in the upper naspharyngeal airway spaces secondary to RME. Materials and methodsSeventeen participants (8 male, 9 female, with a mean age of 12.6 ± 1.8 years), who required RME for the management of narrow maxillary arch, were recruited for this study. The prescribed expansion regimen was quarter turn (0.25 mm), twice a day until over-expansion was achieved. The mean period for the active phase was 14 days with a range of 12–21 days. Pretreatment (T1) and immediate post-expansion (T2) CBCT images were obtained and then processed using ITK snap and OnDemand3D softwar packages. Paired t-test and Interclass Correlation Coefficient (ICC) were used to assess the reproducibility of the measurements, student t-test (P < 0.05) and Pearson Correlation Coefficient (PCC) were applied to evaluate the volumetric changes in the nasopharyngeal airway spaces, linear dentolaveolar changes and correlate these changes. Main findingsThough, the data of one patient was excluded from the study, owing to major differences (>5 degrees) in the head and neck posture between T1 and T2 CBCT scans, the study' findings shows that bonded RME is an effective dentoalveolar expander in growing patients (P= 0.01) with an average expansion of 3.7 mm and 2.8 mm in males and females respectively. Likewise, the upper nasopharynx (UNP) expanded significantly (15.2% in males and 12% in females). In comparison, the upper retropalatal space (URP) was significantly reduced, by almost one sixth of its original volume, more in males than females, 11.2% and 2.8% respectively. A strong direct correlation between the maxillary sinus volumetric changes, and between appliance expansion and dentoalveolar expansion were evident (PCC = 0.86, 0.75, respectively). There was also a moderate correlation between changes in the UNP and URP spaces. ConclusionsRME was found to be an effective dentoalveolar expander and significantly augment the UNP and minimize the URP space. A similar comparative clinical study with long-term follow-up would be beneficial in accurately deteremining the clinical impact of RME on the airway and breathing as well as the stability of these effects.

Management of Adult Transverse Malocclusion with Surgically Assisted Rapid Palatal Expansion.

An-18-year old male patient reported to the Department of Orthodontics, SVS Institute of Dental Sciences, Mahabubnagar, with a chief complaint of irregularly placed upper and lower front teeth and restless sleep. On extra oral examination the patient presented with mild convex profile, competent lips and normal nasolabial angle and mentolabial sulcus with no gross asymmetry. Intraoral examination showed severe crowding in both the arches, Class I molar and canine relationship bilaterally, narrow maxillary arch, blocked out upper right canine, upper right lateral incisor and posterior unilateral cross bites, upper midline shifted to right side by 3mm. Cephalometric examination showed that patient exhibited Class I skeletal jaw bases (ANB: 20) with normal mandibular plane angle (FMA: 260), upright upper anteriors (UI-SN: 1020) retroclined lower anteriors (LI-MP: 720), with normal nasiolabial angle (1080) as shown in [Table/Fig-1]. Model analysis suggested 7mm expansion is possible in the upper arch and 5mm of space can be gained in the lower arch.

Hybrid Rapid Palatal Expansion With 2 Mini-Screws: A Case Report

ABSTRACT A hybrid expander is a newly designed bone-anchored expander consisting of 2 mini-screws and palatal acrylic; it does not cover any teeth. The aim of this case report is to present the treatment of a patient with transversal maxillary deficiency by hybrid expander. An 11.4-year-old female patient came to our clinic complaining about the appearance of her teeth. She had a narrow maxillary arch, unilateral dental crossbite, anterior dental crowding, and dental Class II canine and molar relationships on both sides. Two self-tapping mini-screws were placed between the first molar and second premolar on the palate under minimal local anesthesia. After 1 week, this appliance was bonded to the mini-screws with Transbond XT (3M Unitek, Monrovia, CA, USA) resin. The expansion screw was activated twice a day for 1 week and then once a day until the expansion was completed. After the expansion period, the brackets were bonded to the teeth without removing the hybrid expander. Sufficient maxillary expansion ...

Orthopedic Treatment of Maxillary Expansion: A Review of the Literature

The narrow maxillary arch compared to the mandibular arch usually results in the transversal discrepancy of posterior teeth.Characterized by unilateral or bilateral crossbite, it is necessary to expand the constricted upper arch in order to correct the transverse discrepancy in these malocclusion cases. [1] By dental tipping and midpalatal suture opening, the dentofacial abnormity including transverse maxillary deficiency, unilateral crossbite and minimal crowding can be corrected. There are different types of methods and appliances for maxillary enlargement, but since the midpalatal suture becomes more tortuous and interdigitated with increasing age [2], arch expansion is suggested to initiate before pubertal peak in skeletal growth.

Myofunctional and dentofacial relationships in second grade children.

One hundred and thirty-three second graders in rural public school were assessed on a number of dental, skeletal, and oral muscle function measures. Correlational analyses were conducted in order to determine whether specific myofunctional variables were associated with dentofacial development. Significant relationships were observed between open mouth posture and a narrow maxillary arch and long facial height. Labial and lingual rest and swallow patterns were also related to poor coordination of lip and tongue movements.

Biomex Quad Helix

Introduction: Anterior deep bite with narrow maxillary arch is a most common clinical situation orthodontists have to deal with in Class I as well as Class II malocclusions.Objective: To present a modification of the quad helix appliance which incorporates acrylic anterior bite plane for simultaneous bite opening with maxillary expansion (Biomex Quad helix). Appliance design: The appliance is made of 0.036 inch stainless steel wire. The anterior bridge of the quad helix is modified by extending it anteriorly. The wire is soldered to the stainless steel bands on the maxillary first permanent molars. Acrylic anterior bite plane is added to this anterior extension keeping the anterior helices exposed. It combines advantages of a quad helix with that of anterior bite plane. Hence it can be useful for simultaneous bite opening with maxillary expansion, deprogramming, and relieving TMJ symptoms by unlocking the occlusion.Conclusion: Biomex Quad Helix is a versatile appliance which is simple in design, easy to fabricate, comfortable for the patient, and economical for the operator and the patient.

Is maxillary dental arch constriction common in Japanese male adult patients with obstructive sleep apnoea?

OBJECTIVES Little is known about the contributions of a narrow maxillary dental arch and maxillary skeletal constriction to the development of obstructive sleep apnoea (OSA). Therefore, the purpose of this study was to clarify the relationships between maxillary dental arch width and OSA and between maxillary skeletal constriction and OSA in Japanese male patients.METHODS Study models for 164 Japanese male OSA patients were fabricated for dental arch analyses. We compared the patients' dental arch widths with the standard value for Japanese males. Moreover, the associations between the upper dental arch width and the apnoea-hypopnoea index (AHI), body mass index, skeletal pattern (SNA, SNB, and ANB), cross-sectional area of tongue obtained from an upright lateral cephalogram, lower dental arch width, overjet, and overbite were also examined.RESULTS Although a narrower upper dental arch was associated with severer OSA, the upper dental arch in OSA patients was not significantly narrower than the Japanese standard value. However, the results of a multiple regression analysis revealed that the upper dental arch became narrower as the mandible was positioned more rearward relative to the maxilla.CONCLUSIONS We conclude that dental arch constriction in the maxilla could be associated with the development of OSA but is not a typical feature of our sample of Japanese OSA patients. Moreover, the factor that aggravates OSA is not maxillary skeletal constriction but rather maxillary dental arch constriction related to antero-posterior skeletal discrepancy.

A Case of Sotos Syndrome Treated with Distraction Osteogenesis in Maxilla and Mandible

Sotos syndrome is inherited in an autosomal-dominant manner and is characterized by increased birth weight, excessive growth, advanced bone age, and distinctive facial features, including dolichocephaly, hypertelorism, and a prominent mandible. We treated a jaw deformity due to Sotos syndrome consisting of malocclusion due to a narrow maxillary dental arch and mandibular retrusion from hypoplasia of the rami. The patient was a 17-year-old man. Malocclusion due to a narrow maxillary dental arch and mandibular retrusion was diagnosed. Rapid maxillary expansion with Lines corticotomy and mandibular advancement with distraction osteogenesis were performed. The maxilla was expanded laterally a total of 3 mm and the mandible prolonged 12 mm in the posterior area of the mandibular body. Subsequently, orthodontic treatment was continued. At present, 5 years after surgery, occlusion remains good and stable.