'Study of the maxillary yaw on cone beam computed tomography: A preliminary report and comparison between two different dento-skeletal malocclusions'.

OBJECTIVES: To assess the skeletal and dental maxillary transverse compensation (yaw) on the cone beam computed tomography (CBCT) three-dimensional reconstructed image of the skull in two groups of patients, both clinically affected by a class III malocclusion with deviation of the lower midline. MATERIALS AND METHODS: An observational retrospective study was designed to analyse differences in two groups of patients, the first one was composed by patients affected by horizontal condylar hyperplasia, the second one by patients affected by dento-skeletal asymmetric class III malocclusion. Each group was composed by 15 patients. Transverse analysis was performed by measuring five landmarks (three bilateral and two uneven) with respect to a mid-sagittal plane; sagittal analysis was performed by measuring the sagittal distance on the mid-sagittal plane between bilateral points. Means were compared through inferential analysis. RESULTS: In the condylar hyperplasia group, all differences between the two sides were not statistically significant, nor for canines' difference (P = .0817), for molars (P = .1105) or for jugular points (.05871). In the class III group, the differences between the two sides were statistically significant for molars (P = .0019) and jugular points (P = .0031) but not for canines (P = .1158). Comparing the two groups, significant differences were found only for incisors' midline deviation (P = .0343) and canine (P = .0177). CONCLUSION: The study of the yaw on CBCT should be integrated into three-dimensional cephalometry and could help in differentiating the various malocclusion patterns.

Temporomandibular joint articular disc position and shape in skeletal Class III.

OBJECTIVE: To compare the position and shape of the temporomandibular joint (TMJ) articular disc among the sagittal and vertical skeletal patterns in Angle Class III, Class III subdivision malocclusion and normal occlusion. The null hypothesis was that there was no difference in disc position and shape in different (1) malocclusions and (2) skeletal patterns. METHODS: This cross-sectional observational study evaluated 105 patients divided into 3 groups: Class III (33, 9.39 ± 1.96 years), Class III subdivision (45, 9.51 ± 1.59 years) and a normal occlusion (27, 10.24 ± 0.87 years) was included as healthy control. Severity of the maxilla-mandibular anteroposterior discrepancy and vertical facial pattern were determined using 2D cephalometry, and the position and shape of the articular discs were evaluated in magnetic resonance images. Statistical parametric and non-parametric tests and Kappa analysis for intra-observer and inter-observer assessment were used (p ≤ .05). RESULTS: Significant between-group differences were found in articular disc position. In the normal occlusion group, all the articular discs were well positioned. In Class III and Class III subdivision, the discs were displaced in 30.3% and 12.2% of the TMJs, respectively. Sagittal and vertical skeletal patterns did not affect the findings significantly. The Class III subdivision malocclusion group is probably different from the other groups, showing 97.7% of biconcave discs in both TMJs. CONCLUSION: The longitudinal follow-up of this sample becomes relevant as the two groups with malocclusion in the pre-peak phase of pubertal growth showed differences in the prevalence of displacement and form of the articular disc, with no association with their vertical facial characteristics.

Skeletal Class III Malocclusion Is Associated with ADAMTS2 Variants and Reduced Expression in a Familial Case.

Skeletal Class III malocclusion with maxillary deficiency is a severe maxillofacial disease with unclear pathogenic mechanisms. We recruited a Han Chinese family who was clinically diagnosed with skeletal Class III malocclusion and maxillary deficiency. Using whole exome sequencing, a missense variant in ADAMTS2 (NM_014244: c.3506G>T: p.G1169V) was identified and predicted as deleterious by in silico tools. We also found ADAMTS2 variants associated with deficient maxillary development in a cohort. ADAMTS2 expression in HEK293 cells showed significant decrease due to the variant, which was also consistent in dental pulp stem cells from the proband and a healthy control. In the adamts2-knockdown zebrafish model, the length and width of the ethmoid plate, as well as the length of the palatoquadrate became significantly shorter than the control group (p < 0.001), while there was no significant difference in the length and width of the mandible. The expression of Sox3, which was required in early embryonic craniofacial development, was significantly downregulated in the adamts2-knockdown zebrafish embryos. Bioinformatic and cellular studies showed that the decreased expression of ADAMTS2 may inhibit downstream ErbB signaling pathway transduction and restrain subsequent osteogenesis in human adult mesenchymal stromal cells. Collectively, these data showed that ADAMTS2 (c.3506G>T: p.G1169V) may confer susceptibility to risk of skeletal Class III malocclusion with maxillary deficiency.

Accuracy Assessment of Virtual Surgical Planning Comparing 3D Virtual Surgical Planning and Post-Operative CBCTs in Surgical Skeletal Class III Cases: A Retrospective Study

ABSTRACT Objective: To evaluate the accuracy of Virtual Surgical Planning (VSP) comparing VSPs and post-operative CBCT scans in patients undergoing bimaxillary orthognathic surgery of severe Skeletal Class III malocclusion. Material and Methods: Twenty-three patients (9 males and 14 females, mean age 24.1 ± 7.0 years) were selected and submitted to bimaxillary orthognathic surgery. Pre-operative VSPs and post-operative CBCTs were compared using both linear (taking into account four skeletal and six dental landmarks, each one described by the respective coordinates) and angular measures (seven planes in total). The threshold discrepancies for post-operative clinical acceptable results were set at ≤2 mm for liner and ≤4° for angular discrepancies. The mean difference values and its 95% confidence interval were identified, comparing which planned and which obtained in absolute value. Results: There were significant statistical differences for all absolute linear measures investigated, although only two overcome the linear threshold value of 2mm in both X and Y-linear dimensions. Linear deviations in Z-linear dimension do not reach statistical significance. All 12 angular measures reach the statistical significance, although none overcome the threshold angular value of 4°. Angular deviation for roll register the higher accuracy in contrast to pitch and yaw. Conclusion: Virtual surgical planning is a reliable planning method to be used in orthognathic surgery field; as a matter of fact, although some discrepancies between the planned on the obtained are evident, most of them meet the tolerability range.

Comparison of three-dimensional soft-tissue evaluations between skeletal and pseudo-class III malocclusions.

The aim of our study was to compare soft tissue measurements with 3D imaging methods in individuals with untreated skeletal and pseudo-Class III malocclusions. The study sample consisted of 75 patients (38 males, 37 females, mean age 12.41 ± 2.35 years) with pseudo- and true skeletal Class III malocclusions and skeletal Class I malocclusions. Soft tissue evaluations of all patients were performed using 3D stereophotogrammetric facial images. In our study, 26 landmarks, 17 linear measurements, 13 angular measurements, and 5 volume measurements were made using the 3dMD Vultus software. The significance was determined to be p < 0.05 in ANOVA, Tukey tests. No significant differences were found among the groups in terms of demographic data (p > 0.05). The skeletal Class I control group had a significantly more extended upper lip and vermillion length as compared to the Class III groups. The soft tissue convexity angle and upper nasal angle were found to be wider in the Class III malocclusion group compared to those in the Class I control group. While the pseudo-Class III group had a significantly lower midface volume, chin volume was significantly higher in the skeletal class group. Upper lip volume was significantly higher in the Class I group. Using 3dMD for guiding clinicians in the differential soft and hard tissue diagnosis of pseudo-Class III malocclusions, differences were revealed in Class I patients in the middle part of the face. In the differential diagnosis of true Class III malocclusions, chin volume was found to be different from that of Class I patients.

Morphological changes of frankel functional regulator III in mixed dentition with class III malocclusion / Cambios morfológicos del regulador funcional frankel III en dentición mixta con maloclusión clase III

The aim of this study was to evaluate the hard and soft tissue profile changes following treatment of functional and mild skeletal class III malocclusion in mixed dentition by means of the Frankel functional regulator (FR-3) appliance, and to reveal the mechanism and effectiveness of treatment with FR-3 appliance. Twenty-six patients (chronological mean age, 8.7±1.4 years; mean treatment duration, 10.3±1.3 months) with functional and mild skeletal class III malocclusion were selected and treated with FR-3 appliances. Lateral cephalogram was taken pre- and post-treatment, and the data was analyzed by paired-samples t test with SPSS22.0 software package. Differences were considered statistically significant at P < 0.05. The results demonstrated that the FR-3 appliance produced a statistically significant decrease in L1-NB, L1-MP, U1-L1 (P<0.01) and an increase greatly in ANB, MP-FH, Y axis, ANSMe, ANS-Me/N-Me and overjet (P<0.01). SNA, SNB were increased significantly (P<0.05). Meanwhile, N'-Sn-Pog', ULSn-SN, LLSiSN increased, S-N'-Si, LL-EP decreased with significant difference (P<0.01). S-N'-Sn, Cm-Sn-UL, UL-EP, Sn-Mes and Ns-Mes increased with significant difference (P<0.05). Therefore it was concluded that after FR-3 treatment, the position of mandible may rotate clockwise backwards and downwards, with the labioversion of upper incisors and linguoversion of lower incisors. Although point A moved mesially, the length and position of the maxilla did not change significantly. With the protrusion of upper lip and the retrusion of lower lip, the relationship among nose, upper lip, lower lip and chin become harmonious, the profile of soft tissue is more coordinated and attractive.

El objetivo de este estudio fue evaluar los cambios en el perfil de los tejidos duros y blandos después del tratamiento de la maloclusión funcional y leve de la clase III esquelética en la dentición mixta mediante el aparato regulador funcional Frankel (FR-3), y revelar el mecanismo y efectividad del tratamiento con el aparato FR-3. Veintiseis pacientes (edad media 8,7 ± 1,4 años; duración media del tratamiento, 10,3 ± 1,3 meses) con maloclusión funcional y leve de clase esquelética III fueron seleccionados y tratados con aparatos FR-3. El cefalograma lateral se tomó antes y después del tratamiento, y los datos se analizaron mediante la prueba t de muestras con el software SPSS22.0. Las diferencias se consideraron estadísticamente significativas a P <0,05. Los resultados demostraron que el dispositivo FR-3 produjo una disminución estadísticamente significativa en L1-NB, L1MP, U1-L1 (P <0,01) y un gran aumento en ANB, MP-FH, eje Y, ANS-Me, ANS -Me / N-Me y overjet (P <0,01). SNA, SNB se incrementaron significativamente (P <0,05). Mientras tanto, N'Sn-Pog', ULSn-SN, LLSi-SN aumentaron, S-N'-Si, LL-EP disminuyeron con una diferencia significativa (P <0,01). S-N'-Sn, Cm-Sn-UL, UL-EP, Sn-Mes y Ns-Mes aumentaron con una diferencia significativa (P <0,05). Por lo tanto, se concluyó que después del tratamiento con FR-3, la posición de la mandíbula puede girar en sentido reloj hacia atrás y hacia abajo, con labioversión de los incisivos superiores y linguoversión de los incisivos inferiores. Aunque el punto A se movió mesialmente, la longitud y la posición del maxilar no cambiaron significativamente. Con la protuberancia del labio superior y la retrusión del labio inferior, la relación entre la nariz, el labio superior, el labio inferior y el mentón se armoniza, el perfil del tejido blando es más coordinado y atractivo.

Surgically assisted maxillary expansion; about a clinical case.

INTRODUCTION: By means of orthopedics, orthognathic surgery or orthodontics, the management of the maxillary transverse defisciency is a key element of the orthodontic treatment plan, and the guarantee of its stability. the following work aims to support, through a clinical case, the management and the progression of the treatment of the maxillary transverse deficiency associated to a class III skeletal anomaly. OBSERVATION: The authors report the case of a 15-year-old patient with a severe class III    malocclusion, with severe maxillary transverse deficiency. The objectives of the treatment were, first, to solve the transverse disharmony by surgically assisted rapid maxillary expansion (SARME), then, secondly, to remove the dentoalveolar compensations and a bimaxillary orthognathic surgery, was carried out to correct the sagittal and vertical disharmony. CONCLUSION: Surgically assisted rapid maxillary expansion (SARME) appears to be advantageous, both functionally and aesthetically to overcome transverse maxillary deficiency. The agreement between the orthodontist, the maxillofacial surgeon and / or the plastic surgeon, both in the schedule and in the choice of surgical interventions, remains decisive concerning ortho-surgical treatments.

Three-dimensional evaluation of skeletal and dental changes in patients with skeletal class III malocclusion and facial asymmetry after surgical-orthodontic treatment.

OBJECTIVE: To evaluate skeletal and dental changes in patients with skeletal Class III malocclusion and facial asymmetry after surgical-orthodontic treatment using cone-beam computerized tomography (CBCT). METHODS: This study included forty adult patients diagnosed with skeletal Class III malocclusion and asymmetry who underwent either isolated mandibular surgery or bimaxillary surgery. CBCT scans were taken before treatment (T0), at the completion of presurgical orthodontic treatment (T1) and after treatment (T2). Mimics 17.0 and 3-Matics 7.0 were used to measure skeletal and dental parameters. Skeletal and dental changes within each group from pretreatment to posttreatment were assessed, and Pearson correlation analysis was used to analyze the correlations among skeletal changes. RESULTS: The three-dimensional changes in condylar position were insignificant after surgical-orthodontic treatment in either group (P > 0.05). However, in the one-jaw surgery group, there were significant backward rotations of the condyle and ramus on the nondeviated side (P < 0.05), and the condyle on the deviated side rotated inward and forward significantly in the two-jaw surgery group (P < 0.05) at T2. There were no significant differences in the changes in the total alveolar bone thickness of bilateral first molars during dental decompensation (P > 0.05). The ratio between the buccal and the total bone thickness around the maxillary first molar on the deviated side decreased significantly at T1, as did those around the mandibular first molar on the nondeviated side (P < 0.05). CONCLUSIONS: Condylar angulations were less stable after treatment (7 to 9 months after surgery) in both the one-jaw and the two-jaw surgery groups, while condylar displacements were insignificant. In addition, orthodontists should keep a watchful eye to the relative position of the root in the alveolar bone during tooth decompensation.

CBCT Analysis of Changes in Dental Occlusion and Temporomandibular Joints before and after MEAW Orthotherapy in Patients with Nonlow Angle of Skeletal Class III.

This study focus on the changes of the position and morphology of jaw and condyle after MEAW (the multiloop edgewise arch wire) treatment in adults with a nonlow angle (mean angle or high angle SN - MP > 27°) of skeletal class III (mild to moderate skeletal classs III means -5° < ANB < 0°) malocclusions measured by CBCT (cone beam computed tomography). Twenty adult patients (aged 17-26) with a nonlow angle of skeletal class III malocclusions were selected in this study taken orthodontic treatment by MEAW. CBCT was taken before and after the treatment to analyze the changes of the jaw and condyle. After treatment, the angle of L7-MP decreased 12.2°, L6-MP decreased 10.5°, L1-MP decreased 8.8° (P < 0.001 for each) and U1-SN increased (P < 0.05). There was no significant changes between anterior and posterior APDI index and between anterior and posterior spaces of the TMJ (temporomandibular joint) (P > 0.05). The linear ratio of the TMJ was the LR > 12 before treatment, while it was -12 < LR < 12 after treatment; however, there was no statistically significant difference between them (P > 0.05). There was also no significant change in anterior and posterior position and morphology of the condyle within the joint fossa after the treatment by MEAW in this study. MEAW technology in correcting the class III with nonlow angle patients mainly relies on the compensation of distally and posterior mandibular teeth, rather than the mandible and condyle moving backward to establish a neutral occlusal. This study was approved by the institutional ethics committee of the Second Hospital of Tianjin Medical University (No. KYJJ2013002).

Evaluation of sagittal airway dimensions after face mask therapy with rapid maxillary expansion in Class III growing patients.

OBJECTIVE: The aim of this investigation was to analyze the effects of RME and FM on the airway dimensions in Class III patients compared with untreated controls. METHODS: A sample of 47 Class III patients treated with RME and FM was analyzed. The treated group was compared with 18 untreated controls. Lateral cephalograms for each patient at T1, T2, and T3 were digitized. RESULTS: At long-term evaluation a significant increase in airway size and a significant decrease in adenoid size were found in the treated group as well as an improvement in the pharynx dimension. During active treatment the treated group showed a significant improvement in lower airway size and in lower pharynx dimension. A significant decrease in adenoid size was also found. CONCLUSION: The treatment with RME and FM produced favorable stable changes in the airway dimensions in Class III subjects when compared with untreated controls.

Dentoskeletal morphology in adults with Class I, Class II Division 1, or Class II Division 2 malocclusion with increased overbite.

INTRODUCTION: The treatment options for adults with increased overbite are limited to dentoalveolar changes that camouflage the condition. Because of high relapse tendency, defining the problem area is important when creating a treatment plan. This study aimed to evaluate dentoskeletal morphology in skeletal Class I and II anomalies associated with Angle Class I, Class II Division 1 (Class II/1), and Class II Division 2 (Class II/2) malocclusions with increased overbite compared with normal occlusion. METHODS: Pretreatment cephalograms of 306 patients (131 men, 175 women; overall ages 18-45 years) were evaluated. Four groups were constructed. Three groups had increased overbite (>4.5 mm): group 1 (n = 96) skeletal Class I (ANB = 0.5°-4°), group 2 (n = 85) skeletal Class II (ANB >4.5°) with Class II/1; and group 3 (n = 79) skeletal Class II with Class II/2 malocclusion. Group 4 as a control (n = 46) skeletal Class I normal overbite. Dental and skeletal characteristics of the groups were compared by sex. For statistical evaluations, analysis of variance followed by Tukey post hoc, Mann-Whitney U, and Kruskall-Wallis tests were used. Additionally correlation coefficients between overbite and skeletal/dental parameters were calculated. RESULTS: Between sexes, with regard to skeletal parameters, the men had greater values in millimetric measurements, and the women had higher SN/GoGn values. Maxillary/mandibular molar heights and the mandibular incisor heights were higher in men. In group 1, decreased lower anterior facial height (LAFH), retrusive mandibular incisors, and increased interincisal degree were determined. The maxillary molars were intrusive, whereas the vertical position of the mandibular molars and incisors in both jaws were normal. In group 2, retrognathic mandible, increased LAFH and mandibular plane angle, extrusive maxillary/mandibular incisors, protrusive mandibular incisors, and decreased interincisal degree were found. In group 3, decreased LAFH, increased interincisal degree, and retrusive incisors in both jaws were determined. There were significant negative correlations between SN/GoGN, palatal plane, and overbite in group 2 and between ANS-SN and overbite in group 3, and positive correlation between interinsical angle and overbite in all increased overbite groups. CONCLUSIONS: Dental morphology seems to be the main factor of increased overbite. Differences between groups were related primarily to inclinations and vertical positions of the incisors, rather than molar positions.

Corticotomy-assisted adult rapid maxillary arch expansion and ridge augmentation: An interdisciplinary case report with 7-year follow-up.

Adult orthodontic treatment involving maxillary transverse deficiency is a challenge for an interdisciplinary team. Surgically assisted rapid palatal expansion to segment the maxilla was once the treatment of choice, but the invasiveness, bone deficiency, and gingival recession hindered its acceptance. Corticotomy-assisted rapid maxillary arch expansion with ridge augmentation has the advantage of augmenting alveolar bony housing to accommodate and facilitate tooth movement. This approach was used to correct a severely constricted maxilla with bilateral posterior crossbite and anterior crowding in a 46-year-old man. Treatment time was 14 months. The accelerated arch expansion overcame the crossbite in 7 months, increasing intercanine distance by 5.2 mm and intermolar distance by 9.8 mm. Subsequent implant prosthesis was able to be restored in a functional normal occlusion. Satisfactory and stable clinical outcome was followed for 7 years. Corticotomy-assisted rapid maxillary arch expansion with alveolar bone augmentation is a novel and effective interdisciplinary approach for correcting adult maxillary transverse deficiency. Well controlled prospective clinical trails are warranted for further investigation.

Three novel genes tied to mandibular prognathism in eastern Mediterranean families.

INTRODUCTION: Mandibular prognathism (MP) is subject to major polygenic influence and segregates within families in autosomal dominance with variable expressivity and incomplete penetrance. We aimed to identify the inheritance pattern and genes and loci involved in the development of MP in Mediterranean families and to evaluate the dentoskeletal characteristics of affected individuals. METHODS: Fifty-one eastern Mediterranean families with individuals affected by MP were identified. Data and biospecimens were collected from 14 of the families, including clinical examination, lateral cephalography (on subjects with Class III malocclusion), and 5 mL blood drawn from consenting affected and nonaffected relatives. Next-generation sequencing (NGS) was performed on 8 families (7 Lebanese, 1 Lebanese/Syrian), including large numbers of affected individuals over many generations and severe conditions, with the use of whole-exome sequencing. RESULTS: Most pedigrees suggested autosomal-dominant inheritance with an equal number of affected male and female individuals. Affected individuals had macrognathic and prognathic mandibles with dentoalveolar compensation. Genetic screening did not correspond with previously reported MP-linked genes, but yielded 3 novel genes (C1orf167, NBPF8, NBPF9) on chromosome 1 potentially responsible for mandibular development and macrognathism. CONCLUSIONS: In this first genetic study with the use of NGS on the largest reported number of families with MP, novel genes (C1orf167, NBPF8, NBPF9) were associated with familial MP in the eastern Mediterranean population.

Developmental association of palatal dimensions and palatal rugae characteristics in Angle´s classes I, II and III of malocclusion / Asociación de desarrollo de las dimensiones palatinas y las características de las rugas palatinas en las clases I, II y III de maloclusión de Angle

During development, bony changes in the palate are reflected in the palatal rugae. Therefore, we hypothesized that the palatal dimensions (PD) influence the shape and number of palatal rugae (PR). The objectives were to record the palatal rugae characteristics (PRC) and palatal dimensions (intercanine distance (ICD), intermolar distance (IMD), palatal height (PH) and palatal area (PA) in Classes I, II and III malocclusion patients and investigate their interrelationship, and statistically examine the possibility of predicting PRC with the PD. Four hundred eighty-one pre-orthodontic study casts of healthy patients with normal palate anatomy were grouped as Classes I, II and III and scanned using 3D cast scanner. The PRC, ICD, IMD, PH, and PA were recorded digitally using 3D enabled software. The data was statistically analyzed. A strong statistically significant difference was observed between PA and number of straight and wavy rugae. ICD and the number of straight rugae were also related. A weak correlation exists between malocclusion classes and PA. The remaining rugae characteristics did not exhibit any relation with palatal dimensions. PA is positively related to the number of straight rugae and negatively related to the number of wavy rugae. Bigger palates have more straight rugae and less number of wavy rugae. A weak correlation between PA and Angle's class I malocclusion exists. We also propose that PA has a developmental association with the number and shape of PR.

Durante el desarrollo, los cambios óseos en el paladar se reflejan en las rugas palatinas. Por lo tanto, planteamos la hipótesis de que las dimensiones palatinas influyen en la forma y el número de las rugas palatinas. Los objetivos fueron registrar las características de las rugas palatinas y las dimensiones palatales (distancia intercanina, distancia intermolar, altura palatina y área palatina) en pacientes con maloclusión de clases I, II y III e investigar su interrelación, y examinar estadísticamente la posibilidad de predecir las características de las rugas palatinas con las dimensiones palatinas. Cuatrocientos ochenta y un estudios pre-ortodónticos de pacientes sanos con anatomía normal del paladar se agruparon como Clases I, II y III y se escanearon con un escáner de emisión 3D. La distancia intercanina, distancia inter molar, altura palatina y área palatina se registraron digitalmente utilizando el software 3D. Los datos se analizaron estadísticamente. Se observó una diferencia estadísticamente significativa entre la altura palatina y el número de rugas rectas y onduladas. Se registró también la distancia intercanina y el número de rugas rectas. Existe una correlación débil entre las clases de maloclusión y la altura palatina. Las características restantes de las rugas palatinas no mostraron ninguna relación con las dimensiones palatinas. El área palatina está relacionada positivamente con el número de rugas rectas y negativamente relacionada con el número de rugas onduladas. Los paladares más grandes tienen más rugas rectas y menor cantidad de rugas onduladas. Existe una correlación débil entre el área palatina y la clase I de maloclusión de Angle. También proponemos que el área palatina tiene una asociación de desarrollo con el número y la forma de rugas palatinas.

Effect of sagittal split ramus osteotomy on morphologic parameters of temporomandibular joint in patients with mandibular prognathism.

The purpose of this study was to evaluate the change in three-dimensional morphology and clinical symptoms of temporomandibular joint (TMJ) in class III dentofacial deformity patients postoperatively for 6 months after sagittal split ramus osteotomy (SSRO).Seventeen patients with skeletal Class III malocclusion and 10 asymptomatic volunteers (classified as Control group) were recruited for the study and underwent cone-beam computed tomography scanning. The geometries of the maxilla and mandible were reconstructed using MIMICS (Materialise, Leuven, Belgium). The morphologic measurements of the patients' TMJs were done before surgery and at 6-month follow-up - named as Pre and Post groups, respectively.The joint spaces (medial joint space, superior joint space, lateral joint space, anterior joint space, and posterior joint space) of the Control group were significantly greater than those of the Pre and Post groups (P < .05), and SSRO did not significantly change the TMJ morphology parameters. Five patients were found to have preoperative temporomandibular disorder (TMD) symptoms, and 3 of them were relieved at 6 months after surgery. Postoperative TMD symptom was observed in 1 patient without preoperative TMD symptom.SSRO did not markedly alter the TMJ morphology of the patients with mandibular prognathism. The effects of SSRO on TMD symptoms should be related to the type of deformity.

Hard- and soft-tissue symmetry comparison in patients with Class III malocclusion.

OBJECTIVE: Our aim was to describe hard- and soft-tissue asymmetry in people who have a skeletal Class III malocclusion, and to compare with those without asymmetry. We also performed a regional analysis of a possible correlation between facial soft- and hard-tissue asymmetries. METHODS: This retrospective study was performed with the use of the computed tomographic scans of 60 subjects. The skeletal Class III subjects were categorized into 2 subgroups: soft-tissue menton deviation ≤4 mm (n = 20) versus >4 mm (n = 20). The Class III groups were compared with a Class I symmetry group (n = 20). Hard and soft tissues were segmented into different morphologic areas and deviation calculated. Pearson correlation coefficients were obtained, and 1-way analysis of variance was conducted for statistical analysis. RESULTS: The highest deviation in the hard tissues of the Class III asymmetry group was in the corpus region (5.55 ± 3.05 mm), with the second highest in the angulus region (4.70 ± 2.43 mm). The highest average deviation in the soft tissues was seen in the lower cheek (7.04 ± 3.46 mm). In the different study groups, the amounts of asymmetry measured in anatomic structures on the mandible were found to be highly correlated between neighboring structures. CONCLUSIONS: Clinically and statistically significant differences were found in the anatomic regions located in the middle and lower thirds of the face. There was a medium or high correlation between condyle, coronoid process, ramus, and angulus regions. A low level of correlation was observed between middle face and mandibular asymmetries in hard-tissue upper cheek and lower cheek regions were correlated with different mandibular regions.

Exploiting the interplay between cross-sectional and longitudinal data in Class III malocclusion patients.

The aim of the study was to investigate how to improve the forecasting of craniofacial unbalance risk during growth among patients affected by Class III malocclusion. To this purpose we used computational methodologies such as Transductive Learning (TL), Boosting (B), and Feature Engineering (FE) instead of the traditional statistical analysis based on Classification trees and logistic models. Such techniques have been applied to cephalometric data from 728 cross-sectional untreated Class III subjects (6-14 years of age) and from 91 untreated Class III subjects followed longitudinally during the growth process. A cephalometric analysis comprising 11 variables has also been performed. The subjects followed longitudinally were divided into two subgroups: favourable and unfavourable growth, in comparison with normal craniofacial growth. With respect to traditional statistical predictive analytics, TL increased the accuracy in identifying subjects at risk of unfavourable growth. TL algorithm was useful in diffusion of information from longitudinal to cross-sectional subjects. The accuracy in identifying high-risk subjects to growth worsening increased from 63% to 78%. Finally, a further increase in identification accuracy, up to 83%, was produced by FE. A ranking of important variables in identifying subjects at risk of growth worsening, therefore, has been obtained.

Changes in cross-sectional measurements of masseter, medial pterygoid muscles, ramus, condyle and occlusal force after bi-maxillary surgery.

PURPOSE: The purpose of this study was to examine changes in masseter and medial pterygoid muscles, ramus, condyle and occlusal force after bi-maxillary surgery in class II and III patients. SUBJECTS AND METHODS: The subjects were 42 patients (84 sides) who underwent sagittal split ramus osteotomy with Le Fort I osteotomy (21 class II cases: mandibular advancement and 21 class III cases: mandibular setback). The cross-sectional measurements of the masseter and medial pterygoid muscles, ramus and condyle were measured in horizontal plane images by computed tomography (CT), before and 1 year after the operation. Occlusal force and contact area were also recorded before and 1 year after the operation. RESULTS: Preoperatively, class II was significantly larger than class III in masseter width (P = 0.0068), masseter area (P < 0.0001) and medial pterygoid length (P < 0.0001). However, class II was significantly smaller than class III in medial pterygoid width (P < 0.0001). After 1 year, class II was significantly smaller than class III in masseter length (P = 0.0017). Class II was still larger than class III in medial pterygoid area after 1 year (P = 0.0343). Class II was significantly larger than class III in condylar angle pre-operatively (P < 0.0001) and after 1 year (P = 0.0006). After 1 year, class II decreased significantly more than class III in condylar thickness (P = 0.0020), condylar width (P < 0.0001) and condylar area (P < 0.0001). CONCLUSION: This study suggested that changes in the cross-sectional measurements of masseter and medial pterygoid muscles and the condyle differed between class II and class III patients, although occlusal force did not significantly change 1 year after surgery in both groups.

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

OBJECTIVES: 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. SETTING AND SAMPLE POPULATION: 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. MATERIAL AND METHODS: 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. RESULTS: The tongue volume was larger in Class-III patients (50.63 cm3 ) than in Class-I patients (44.24 cm3 ; 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). CONCLUSIONS: 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.

Evaluations of the tongue and hyoid bone positions and pharyngeal airway dimensions after maxillary protraction treatment.

OBJECTIVE: To assess changes in the tongue and hyoid bone positions and airway dimensions after maxillary protraction using lateral cephalograms. METHODS: Lateral cephalograms were obtained before (C0) and after (C1) an observation period for untreated children with skeletal Class I malocclusion and before (T0), immediately after (T1), and one year after (T2) maxillary protraction in children with skeletal Class III malocclusion. Cephalometric measurements were compared between the time points in both patient groups. RESULTS: Immediately after maxillary protraction, the tongue moved superiorly and the nasopharyngeal and superior oropharyngeal airway dimensions increased. No significant changes in the middle or inferior oropharyngeal airway dimensions or in the hyoid bone position were noted after treatment. CONCLUSIONS: Maxillary protraction improved tongue posture and modified the nasopharyngeal and superior oropharyngeal airway dimensions in patients with skeletal Class III malocclusion. Consequently, maxillary protraction may restore the intra- and extraoral balance and improve respiratory function.