Long-term skeletodental changes with early and late treatment using modified C-palatal plates in hyperdivergent Class II adolescents.

OBJECTIVES: To compare skeletodental changes between early and late treatment groups using modified C-palatal plates (MCPP) and long-term retention outcomes in hyperdivergent Class II adolescents. MATERIALS AND METHODS: Seventy-one hyperdivergent Class II patients were divided into four groups according to treatment modality and treatment timing: group 1, early treatment with MCPP (n = 16; 9.9 ± 0.9 years); group 2, late treatment with MCPP (n = 19; 12.3 ± 0.8 years); group 3, early treatment with headgear (HG; n = 18; 9.6 ± 0.8 years); and group 4, late treatment with HG (n = 18; 12.1 ± 1.2 years). Lateral cephalograms were taken and skeletal and dental variables were measured. For statistical analysis, paired t-tests, independent t-tests, and multiple regression were performed. RESULTS: The early MCPP group showed a more significant decrease in mandibular plane angle than the late MCPP group did, and vertical control was more efficient in the early group than in the late group. In the MCPP groups, both FMA and SN-GoGn were increased with late treatment but decreased with early treatment, and the difference was statistically significant (P < .01). The early-treatment MCPP group had a significant decrease in SN-GoGn of 0.6° compared with an increase of 1.7° in the early treatment HG group (P < .01). Posttreatment stability of both the early and late MCPP groups was maintained in long-term retention. CONCLUSIONS: Early MCPP showed more significant vertical control than late MCPP. However, there was no difference in long-term stability between early and late groups.

Evaluation of the effect of extraction in comparison to distalization on the maxillary third molars in class II malocclusion: a retrospective study.

OBJECTIVE: To compare the effects of first premolar extraction versus distalization on the vertical position and mesiodistal angulation of maxillary third molars (MxM3) in adolescent class II patients. METHODS: The panoramic x-rays (OPGs) of 200 adolescent class II patients with developing MxM3s were screened. The chosen sample consisted of 2 groups: Group 1 (Distalization) comprising 48 MxM3s, and Group 2 (Extraction) comprising 50 MxM3s. The pre- and post-treatment OPGs were traced to detect the mesiodistal angulation changes of the second molars (MxM2) and MxM3s. RESULTS: The angulation and vertical position of the MxM3s at T0 & T1 were also evaluated using Archer's classification. The distalization group presented a non-significant decrease in the mean angulation of MxM2 and MxM3 (-2.4o & -4.5o uprighting respectively). In the extraction group, both MxM2 and MxM3 presented a highly significant decrease in the mean angulation (-10.5o & -11o uprighting respectively). The angulation and vertical position change of MxM3 significantly improved in the extraction group when compared to the distalization group (P < .001). CONCLUSION: Significant uprighting and occlusal positioning of the maxillary third molars occurred in the premolar extraction treatment group when compared to the distalization treatment group. The results of the current study highlight the importance of recognizing maxillary third molars during orthodontic treatment planning of Class II malocclusion cases.

Biomechanical analysis of total arch maxillary distalization using infrazygomatic crest miniscrews: a finite element analysis study.

AIM: To evaluate the maxillary incisors and canine's immediate movement tendency using three different power arms (PA) height levels during total arch maxillary distalization supported on infrazygomatic crest (IZC) miniscrews according to finite element analysis (FEA). METHODS: Three finite element models of the maxilla were developed based on CBCT imaging of a teenage male patient presenting a Class II Division 1 malocclusion in the early permanent dentition. Maxillary complex, periodontium, orthodontic accessories, IZC miniscrews and an orthodontic wire were digitally created. The PAs were placed between canines and lateral incisors and projected at 4, 7, and 10 mm height distances. After that, distalization forces were simulated between PA and IZC miniscrews. RESULTS: The anterior teeth deformation produced in the FEA models was assessed according to a Von Mises equivalent. The stress was measured, revealing tendencies of initial maxillary teeth movement. No differences were found between the right and left sides. However, there was a significant difference among models in the under-stress areas, especially the apical and cervical root areas of the maxillary anterior teeth. More significant extrusion and lingual tipping of incisors were observed with the 4 mm power arm compared to the 7 mm and 10 mm ones. The 10 mm power arm did not show any tendency for extrusion of maxillary central incisors but a tendency for buccal tipping and intrusion of lateral incisors. CONCLUSION: The maxillary incisors and canines have different immediate movement tendencies according to the height of the anterior point of the en-masse distalization force application. Based on the PA height increase, a change from lingual to buccal tipping and less extrusion tendency was observed for the incisors, while the lingual tipping and extrusion trend for canines increased.

Three-dimensional computed tomography analysis of airway volume in growing class II patients treated with Frankel II appliance.

OBJECTIVE: The purpose of this retrospective study was to assess the airway volume changes associated with the use of Frankel appliance (FR II) in Class II malocclusion patients using three-dimensional cone beam computed tomography (3D CBCT) imaging. MATERIALS AND METHODS: The sample consisted of 31 Class II malocclusion patients (mean age 9.24 ± 1.93 years old, 17 males (54.8%) and 14 females (45.2%)) treated with FR II appliance by the same orthodontist for an average of 9 months ± 20 days. CBCT images were taken before and after treatment and upper airway volume changes were measured using Dolphin 3D software version11.0 (Dolphin Imaging, Chatsworth, CA) and statistically compared. RESULTS: Airway volume of nasal cavity, nasopharynx, oropharynx, hypopharynx and the total airway volume significantly increased after the use of FR II appliance. In addition, significant increase was reported in maxillary base, inter-molar, inter-premolar and inter-canine width. Significant increase in soft tissue thickness was only recorded opposite to CV2. CONCLUSION: The use of the FR II appliance in growing subjects with Class II malocclusion led to a significant increase in the upper airway volume in addition to the anticipated dental and skeletal transverse expansion effects.

Three-dimensional evaluation of condylar morphology after orthodontic treatment in adult patients with Class II malocclusion by cone-beam computed tomography.

BACKGROUND: The aim of this study was to evaluate the condylar morphological changes after orthodontic treatment in adult patients with Class II malocclusion using a Cone-beam computed tomography (CBCT). METHODS: Images of twenty-eight adult patients with Class II malocclusion who have no temporomandibular symptoms were involved in this study. To analyze the post-treatment changes in condylar morphology, mimics 17.0 software was used to measure several values and reconstruct the three-dimensional condyle, including height of the condyle, area and bone mineral density of the maximum axial and sagittal section, volume and bone mineral density of the three-dimensional condyle and condylar head before and after orthodontic treatment. Using SPSS 19.0 software package Paired t-test was applied for comparison of condylar morphology analysis between pre-treatment and post-treatment. RESULTS: Height of condylar head increase significant (P < .05). Bone mineral density showed a decrease in the maximum axial and sagittal section, three-dimensional condyle and condylar head (P < .01). Evaluation of volume revealed that volume of both condyle and condylar head decrease considerably (P < .05). No significant difference was detected in other values ((P > .05). CONCLUSION: Condylar volume decreased and height of condylar head have changed, so we speculated that adaptive bone remodeling of the condyle occurs.

Adult female skeletal anterior open bite treated by customized lingual orthodontic appliance with miniscrews-assisted in vertical control for perfect orthodontic compensation: A case report with 5-year follow-up.

The benefits of lingual orthodontics go beyond appearance. In this case study, a 30-year-old female patient was treated with a custom lingual orthodontic appliance for a Class II high-angle malocclusion, anterior open bite, incisor biprotrusion and crossbite, unilateral second molar scissor bite and dysfunctional tongue thrust. To achieve a counterclockwise rotation of the mandible, implant anchorage was used to control the vertical height. To complete the compensatory therapy, four first premolars were removed. As well as ensuring aesthetics over the 20-month treatment period, the treatment also established a Class I molar relationship, normal overbite and overjet, and improved the facial profile. After a five-year follow-up, the treatment results remained stable.

Invisible treatment with lingual appliance for the correction of an adult class II subdivision with asymmetrical Wilson and Spee curves: A case report.

This article describes a class II subdivision malocclusion successfully treated by an invisible lingual appliance. The combination of en-masse distalization by interradicular palatal mini-screws and inner unilateral class II auxiliaries, first by intermaxillary elastic, later by a class II coil spring, resulted in a dento-alveolar correction, allowing one to maintain the appliance completely invisible. At the same time, the inclination of buccal sectors was normalized by a correct torque expression with set-up overcorrections, resulting in a significant improvement of the buccal corridors. This case report demonstrates the possibility of successfully solving class II division 2 subdivision malocclusion in adult patients without surgery by means of a completely invisible appliance. It also demonstrates that correct levelling and torque expression, for the correction of asymmetrical Spee and Wilson curves, are achievable with an accurate set-up planning. On the other hand, it underlines the necessity of mini-screws, auxiliaries and set-up overcorrections in order to obtain the best results.

Three-dimensional analysis of posterior tooth inclinations in transverse and sagittal relationships: A cross-sectional study.

OBJECTIVE: To compare tooth inclinations in different sagittal skeletal patterns and transverse maxillary relationships three-dimensionally. METHODS: A cross-sectional study carried out with 132 three-dimensional digital models in the complete permanent dentition divided into six groups (n=22); three groups with maxillary atresia: G1- skeletal class I, G2- skeletal class II and G3-skeletal class III; three groups without maxillary atresia: G4- skeletal class I; G5- skeletal class II and G6- skeletal class III. The comparison between the skeletal pattern was performed by the non-parametric tests of Kruskal Wallis and Dunn and between the groups by the non-parametric test of Mann Whitney. RESULTS: Subjects with skeletal class II and maxillary atresia had a greater lingual inclination of the maxillary teeth than those with class I and III; Subjects with skeletal class II without atresia had a less lingual inclination of the mandibular molars than the other classes (p<0.05). The maxillary premolars showed no variation in dental inclination with atresia, independent of the skeletal class in G1, G2, and G3 (p>0.05). The mandibular premolars showed that the groups without atresia G4, G5, and G6 presented no significant difference (p>0.05). Lower premolars in skeletal class III malocclusion individuals with atresia had a more negative inclination than the others. CONCLUSION: There is a difference in the inclination of posterior teeth between individuals with and without maxillary atresia and skeletal classes I, II, and III.

The skeletal and dental effects of Hanks Herbst versus twin block appliances for class II correction in growing patients: a randomized clinical trial.

BACKGROUND: Despite the popularity of the Twin Block (TB) and the Hanks Herbst (HH) functional appliances, there is limited prospective research comparing these removable and fixed designs, respectively. OBJECTIVES: To evaluate and compare the skeletal and dental effects associated with TB and HH functional appliances as well as to detect factors that might influence the success or failure of treatment in adolescents with Class II malocclusion. DESIGN AND SETTING: A parallel-group randomized controlled trial was undertaken in a single-centre hospital in the United Kingdom. METHODS: A total of 80 participants (aged 10-14 years) with overjet of 7 mm or more were randomized to receive either the HH or TB appliance. Cephalometric radiographs were collected at the start of the study and immediately after the withdrawal of the functional appliances and measured using Pancherz analysis. Participants were allocated to the TB or HH group, based on an electronic randomization, stratified for gender and allocation concealed. Blinding to the allocated arm was not possible. However, all data were coded and anonymized to ensure that assessors were blinded to the group allocation. The main outcome was the anterior-posterior skeletal and dento-alveolar changes at the end of the functional phase. RESULTS: Fifteen (37.5%) participants from the TB group and 7 (15.5%) from HH failed to achieve full overjet reduction (<4 mm) after 12 months of treatment. Overjet reduction was 2 mm greater with HH compared to TB (P = .05; 95% CI: 0.2, 3.2). No significant differences regarding skeletal and dental changes were reported, with the exception that participants in HH group experienced greater lower molar protraction (P = .002; 95% CI: -2.8, -0.8) and mandibular incisors advancement (P = .001; 95% CI: -2.9, -1), indicating greater dental than skeletal effects. CONCLUSION: The TB appliance was associated with a higher rate of treatment discontinuation. No significant clinical differences were observed in the skeletal and dental effects, although the HH may be associated with more pronounced effects on the mandibular dentition. CLINICAL TRIAL REGISTRATION: The protocol was registered online before the start of the trial (ISRCTN11717011).

Asymmetry in Class II subdivision malocclusion: Assessment based on 3D surface models.

INTRODUCTION: There is currently no consensus in the literature whether the aetiology of a Class II subdivision is dental, skeletal or both. The aim of this study was to identify and quantify skeletal and dental asymmetries in Class II subdivision malocclusions. METHODS: CBCTs from 33 Class II subdivision malocclusion patients were used to construct 3D volumetric label maps. Eighteen landmarks were identified. The original scan and associated 3D volumetric label map were mirrored. Registration of the original and mirrored images relative to the anterior cranial base, maxilla and mandible were performed. Surface models were generated, and 3D differences were quantified. Statistical analysis was performed. RESULTS: Anterior cranial base registration showed significant differences for fossa vertical difference, fossa roll, mandibular yaw, mandibular lateral displacement and lower midline displacement. Regional registrations showed significant differences for antero-posterior (A-P) mandibular length, maxillary roll, A-P maxillary first molar position, maxillary first molar yaw and maxillary first molar roll. Class II subdivision patients also show an asymmetric mandibular length as well as an asymmetric gonial angle. Moderate correlations were found between the A-P molar relationship and fossa A-P difference, mandibular first molar A-P difference, maxillary first molar A-P difference and maxillary first molar yaw. CONCLUSIONS: This study suggests that Class II subdivisions can result from both significant skeletal and dental factors. Skeletal factors include a shorter mandible as well as posterior and higher displacement of the fossa on the Class II side, resulting in mandibular yaw. Dental factors include maxillary and mandibular first molar antero-posterior asymmetry.

Comparisons of soft tissue changes after Herbst appliance treatment in three different growth phases.

BACKGROUND: This study aimed to compare the soft tissue effects of Herbst appliance in Class II malocclusion patients treated in three different craniofacial growth phases: prepubertal (PRE), circumpubertal (CIR), and postpubertal (POS). METHODS: In total, 95 patients with Class II Division 1 malocclusion previously treated with a Herbst appliance were analyzed. Through the cervical vertebral maturation stages method, patients were allocated into three groups depending on the growth craniofacial phase at the beginning of treatment: PRE, CIR, and POS. Seventeen cephalometric measures were evaluated from each lateral radiograph before and after Herbst therapy using the Radiocef 2 software (Radio Memory, Belo Horizonte). Intragroup and intergroup treatment changes were compared statistically using a paired t test and MANOVA test, respectively. RESULTS: Soft tissue thickness changes were related only to mandible; all three mandibular measurements (L1_LL, B_B', and Pog_Pog') showed thickening for the PRE group ranging from 0.92 mm (Pog_Pog') to 2.02 mm (B_B'), and only lower lip thickened overtime for the POS group (L1_LL = 0.99 mm). Soft and hard tissue pogonion displaced anteriorly, but only the soft tissue showed differences among groups; PRE group presented more anterior displacement than POS group (3.61 mm and 1.39 mm, respectively). Hard and soft tissue facial convexity decreased more in the PRE and CIR groups than in the POS group. Mentolabial sulcus depth reduced more in the PRE (1.07 mm) and CIR (1.29 mm) groups than in the POS (0.55 mm) group. Horizontal movement of the skeletal and soft pogonion presented a moderate-high positive correlation (r = 0.783), and hard and soft facial convexity showed a moderate-low positive correlation (r = 0.403). CONCLUSIONS: Herbst appliance therapy produces soft tissue improvements in the three phases of craniofacial growth, being greater in patients in the PRE and CIR phases.

Clear aligner treatment assisted by mini screw for an adult with Class II division 2 malocclusion and a right upper canine completely outside of the dental arch: A case report.

This case report describes a 19-year-old man presented with a 5.7-mm deep overbite, Class II division 2 malocclusion with the right upper maxillary canine completely buccal ectopia, deviated midline in the upper arch, severe crowding and retroclination of the maxillary and mandibular incisors. The patient was treated with clear aligners to correct the Class II relationship and the deep overbite. A series of clear aligners were used to move bilateral maxillary molars distally with unilateral mini-screw anchorage. The final results showed that clear aligners with mini-screws could effectively achieve the required upper distal molar movement thanks to a reasonable design of the stages and anchorage. The treatment was completed in 19 months and the patient was satisfied with the treatment outcome in this context of mild to moderate Class II division 2 malocclusion.

Facial profile evaluation and prediction of skeletal class II patients during camouflage extraction treatment: a pilot study.

BACKGROUND: The evaluation of the facial profile of skeletal Class II patients with camouflage treatment is of great importance for patients and orthodontists. The aim of this study is to explore the key factors in evaluating the facial profile esthetics and to predict the posttreatment facial profile esthetics of skeletal Class II extraction patients. METHODS: 124 skeletal Class II extraction patients were included. The pretreatment and posttreatment cephalograms were analyzed by a trained expert orthodontist. The facial profile esthetics of pretreatment and posttreatment lateral photographs were evaluated by 10 expert orthodontists using the visual analog scale (VAS). The correlation between subjective facial profile esthetics and objective cephalometric measurements was assessed. Three machine-learning methods were used to predict posttreatment facial profile esthetics. RESULTS: The distances from lower and upper lip to the E plane and U1-APo showed the stronger correlation with profile esthetics. The changes in lower lip to the E plane and U1-APo during extraction exhibited the stronger correlation with changes in VAS score (r = - 0.551 and r = - 0.469). The random forest prediction model had the lowest mean absolute error and root mean square error, demonstrating a better prediction accuracy and fitting effect. In this model, pretreatment upper lip to E plane, pretreatment Pog-NB and the change of U1-GAll were the most important variables in predicting the posttreatment score of facial profile esthetics. CONCLUSIONS: The maxillary incisor protrusion and lower lip protrusion are key objective indicators for evaluating and predicting facial profile esthetics of skeletal Class II extraction patients. An artificial intelligence prediction model could be a new method for predicting the posttreatment esthetics of facial profiles.

Cephalometric changes in pharyngeal airway dimensions after functional treatment with twin block versus myobrace appliances in developing skeletal class II patients: a randomized clinical trial.

BACKGROUND: Several appliances have been used for correction of developing skeletal Class II, including different myofunctional appliances as Twin block (TB)as well as the new pre-fabricated Myobrace (MB) appliance. However, the effects of these devices on the pharyngeal airways have not been compared in the literature. Thus, the aim of this study was to compare the effects of two Class II correction appliances; TB and MB on the sagittal pharyngeal airway dimension (SPAD), including the nasopharyngeal airway area (NPAA), the oropharyngeal airway area (OPAA), and the laryngopharyngeal airway area (LPAA). METHODS: This is a two parallel arms randomized comparative clinical trial. Twenty-six children of 9-12 years with Skeletal Class II malocclusion due to mandibular deficiency and normal maxillary growth as confirmed by lateral cephalometric X-ray readings (ANB angle > 4° and SNB angle < 78) and Cervical vertebral maturational index (CVMI) 1 or 2 were randomly assigned into two equal groups. Group I: TB, Group II: MB (prefabricated functional appliance, Myofunctional Research Co., Australia). Lateral cephalograms were taken for all patients in both groups before treatment (T1) and after treatment (6 months later) (T2). The primary aim was to assess pre and post treatment changes in the SPAD in each group, and compare between the two study groups. The secondary aim was to evaluate the sagittal skeletal measurements such as the SNA, SNB, ANB, Wits appraisal, as well as vertical skeletal measurements represented by the Frankfurt-mandibular plane angle (FMA) measured pre- and post-treatment. The independent samples t-test was used to compare the two study groups, and the mean difference and 95% confidence intervals (CI) were computed. The paired samples t-test was used to compare various parameters between T1 and T2 within each group. The cutoff for significance was p-value < 0.05. Data were analyzed using IBM SPSS for Windows (Version 26.0). RESULTS: By Comparing changes in airway measurements within each group, it was found that NPAA, OPAA, and LPAA increased significantly after treatment within each group of MB and TB. TB group showed significantly higher mean difference (T2-T1) in both NPAA and OPAA than MB group with 28.39 (± 56.75) and 40.46 (± 52.16) respectively. The increase in LPAA values was not statistically significant at (T2-T1) between both groups. Regarding skeletal changes, there was a significant increase in the SNB values between T1 and T2 within each group with 2.82 (± 3.32) for MB group and 3.79 (± 3.06) for TB group Moreover, there was a significant decrease in the ANB values between T1 and T2 within each group by 2.42 (± 2.70) for MB group and 3.06 (± 1.14) for TB group. Similarly, there was a significant decrease in the ANB values between T1 and T2 within each group by -2.13 (± 0.62) for MB group and - 2.46 (± 0.72) for TB group. No significant differences were found between both groups in SNA, SNB, ANB and Wits appraisal at p = 0.06, p = 0.45, p = 0.43 and p = 0.22 respectively. FMA did not show significant difference between T1 and T2 within each group, nor showed a significant mean difference between both groups at T2-T1. CONCLUSIONS: TB was more effective than MB in improving the upper (NPAA) and middle (OPAA) airways, while no difference was found regarding the lower airway (LPAA). Both TB and MB reduced the severity of developing skeletal class II due to mandibular retrognathism by forward posturing of the mandible. Thus, patients with airway problems would benefit more from TB than MB.

Assessment of Soft Tissue, Airway Dimension and Hyoid Bone Position in Class II Patients Treated by PowerScope Class 2 Corrector.

AIM: This study aims to assess the changes in the soft tissue, pharyngeal airway dimensions, and hyoid bone position in patients treated with PowerScope Class 2 corrector to correct the skeletal Class II pattern. MATERIALS AND METHODS: This study was conducted on a sample of 20 cases diagnosed with Class II malocclusion. The lateral cephalograms were taken before (T1) and after functional appliance therapy (T2) and were traced. The outcomes were compared for the mean changes in soft tissue, airway way dimension, and hyoid bone position. The paired t-test was used for the data comparisons wherein p < 0.05 was kept for statistical significance. RESULTS: The mean values before and after treatment for H angle, mentolabial angle, lower lip E-line, upper lip S-line, lower lip S-line, and lip strain were 19.88 ± 2.77 vs 17.13 ± 1.659, 94.09 ± 12.164 vs 101.75 ± 11.28, -2.47 ± 1.213 vs -1.38 ± 0.976, 3.99 ± 0.19 vs 2.64 ± 0.32, 9.01 ± 0.247 vs 9.43 ± 0.238, 10.24 ± 0.510 vs 10.64 ± 0.52, respectively, which were statistically significant (p < 0.05). All airway spaces (except for lower pharyngeal space) and hyoid bone parameters were significantly improved posttreatment. CONCLUSION: The facial convexity, upper E-line, Z-angle, nasolabial angle, and lower pharyngeal space did not show statistically significant changes. The rest of the soft tissue parameters, oropharyngeal air spaces, and hyoid positioning measured in the study showed significant improvement after treatment with the PowerScope appliance in Class II patients. CLINICAL SIGNIFICANCE: Class II malocclusion is the most common dental anomaly with a high degree of prevalence in the population. This study will help the clinician in understanding the improvement of soft tissue, airway dimension, and hyoid bone position changes on treatment with a fixed functional appliance for the correction of Class II cases, thereby ensuring the greater success of orthodontic therapy in the future.

Effects of Twin-Block with an expanding device on the upper airway in growing children with skeletal class II malocclusion-a retrospective study based on the consistency of three-dimensional and two-dimensional data.

OBJECTIVES: Skeletal class II malocclusion is one of the most common malocclusions. Among the functional appliances for skeletal class II malocclusion, the Twin-Block appliance with a maxillary expander is effective in repositioning the mandible forward. In this study, we focused our efforts on investigating the effects of Twin-Block appliances with maxillary expanders on the upper airway in growing children with skeletal class II malocclusion by tracing and measuring lateral cephalograms after evaluating the consistency of three-dimensional CBCT data and two-dimensional lateral cephalogram data. MATERIALS AND METHODS: A total of 102 patients ranging from 9 to 15 years old (11.37 ± 2.80, male/female ratio = 1:1) with skeletal class II malocclusion were selected to evaluate the consistency of CBCT data and lateral cephalogram data. The strongly and moderately correlated segments were then selected to study the effects of Twin-Block with a maxillary expander on the upper airway in 66 growing children with skeletal class II malocclusion (11.31 ± 1.23 years old, male/female ratio = 1:1) by lateral cephalograms. RESULTS: The results showed a strong significant correlation in the nasopharynx (r = 0.708) and moderate significant correlations in the overall upper airway (r = 0.641), palatopharynx (r = 0.553), and glossopharynx (r = 0.575) but a weak correlation in the hypopharynx (r = 0.323). The corresponding determination coefficient (R2) was also determined by scatter plot analysis. Moreover, compared with the pretreatment data (T1), the total area of the upper airway and the areas of the nasopharynx, palatopharynx, and glossopharynx after functional treatment (T2) increased statistically and significantly. CONCLUSIONS: Lateral cephalograms can reflect the volume of the nasopharynx and oropharynx in skeletal class II children to a certain extent, while Twin-Block appliances with maxillary expanders can widen the volume of the nasopharynx and oropharynx significantly. CLINICAL RELEVANCE: The lateral cephalogram is reliable for analyzing the nasopharynx, palatopharynx, and glossopharynx in orthodontic clinical practice. Twin-Block appliances with maxillary expanders have a positive effect on skeletal class II patients with airway stenosis.

Hard and soft tissue shape variation and changes in Class II division 1 malocclusion during orthodontic treatment: a geometric morphometric analysis.

BACKGROUND: This study aims to determine the hard and soft tissue shape variation and its changes in Class II division 1 malocclusion before and after orthodontic treatment using Geometric Morphometric Analysis. METHODS: This retrospective study included 141 pre-treatment and near-end treatment lateral cephalometric radiographs of Class II division 1 malocclusion patients aged 16-40 years with a skeletal II pattern (ANB > 4o). 32 landmarks in Cartesian coordinates were created and identified using MorphoJ software to establish a shape analysis. RESULTS: The vertical dimensions (hypodivergent to hyperdivergent facial profiles) showed the largest variation in the general shape of hard and soft tissue, followed by the anteroposterior dimensions (mild to severe skeletal II patterns). Variations of lip shape (long to short), lip protuberance (everted to inverted), and nasolabial angle (obtuse to acute) were present. Orthodontic treatment affected the shape of the hard and soft tissue significantly (p < 0.0001). T2 showed significant uprighting of upper incisors (17.5o) and lower incisors (3.7o), improved NLA (8o), an increase in upper lip thickness (1.5 mm), and a reduction in lower lip thickness (0.7 mm) (p < 0.05). CONCLUSION: Vertical and anteroposterior shape variations were found. Orthodontic treatment had an impact on both hard and soft tissue shapes. Hence, understanding both the hard and soft tissue shape variations and the orthodontic treatment changes is crucial for an accurate diagnosis and treatment plan to achieve a successful outcome and excellent patient satisfaction.

Cephalometric comparison of mandibular growth in Brazilian children with Class II malocclusion and normal occlusion during the growth stages determined by the cervical vertebrae maturation.

OBJECTIVE: This study compared mandibular growth in children, aged 7 to 12 years, with Class II malocclusion and normal occlusion, between the following stages of cervical vertebrae maturation: initiation (I), acceleration (A), transition (T). MATERIAL AND METHODS: A total of 148 lateral cephalograms (78 males, 70 females) of Class II malocclusion patients, and 60 lateral cephalograms (30 males, 30 females) of normal occlusion patients were included. The following linear cephalometric measurements were performed: Co-Gn (effective mandibular length), Co-Go (ramus height), and Go-Gn (length of mandibular body). Mean values of increments between stages (I-A, A-T, I-T) were obtained for each group and gender. Results were compared using the Student t-test, and a significance level of 0.05% was adopted. RESULTS: Females group: A-T interval presented a greater increment in Co-Go in the Class II group, which was not significant for the I-T interval, with numerically smaller increments in Co-Gn and Go-Gn, without statistical significance. Males group: intervals I-A, A-T and I-T showed numerically smaller growth increments in the Class II group, with statistical significance for Co-Gn in I-A (p=0.001) and I-T (p=0.003). Comparing genders of the Class II group, Co-Go was higher in males (p=0.002) and I-T interval (p=0.031). In the Normal Occlusion group, the male gender had the greatest Co-Gn (p=0.038) for the I-A interval. In A-T and I-T, Co-Go in males was higher, with statistical significance (p=0.000 and p=0.002, respectively). CONCLUSION: Growth phenomenon affects the mandibular dimensions regardless of the character of the malocclusion, with a tendency to be smaller in the presence of Class II malocclusion.

Changes of Temporomandibular Joint Morphology and Symptoms in Class II Malocclusion Patients With Bilateral Sagittal Split Ramous Osteotomy.

This study included 46 patients with class II malocclusion ranging in age from 19 to 39 years old treated with bilateral sagittal split ramous osteotomy (BSSRO). Left and right temporomandibular joints (TMJs) of each subject were evaluated independently with cone-beam computed tomography (CBCT) before operation (T1), 1 week after operation (T2), and 1 year after operation (T3) and assessed the effects of orthognathic surgery (OGS) on the temporomandibular joint disease (TMD) symptoms. Temporomandibular joint morphology evaluation included condylar volume, condylar area, cortical bone thickness, depth of the mandibular fossa, fossa thickness, joint nodule angle, joint space, and condyle-fossa relationship, which were calculated by using the Mimics software and 3-matic software. Data were statistically analyzed with SPSS software (P <0.05 means statistically significant). In our study, bilateral TMJs have no difference in T3. Bilateral sagittal split ramous osteotomy had no significant effect on the articular fossa. The condyle volume and surface area decreased from T1 to T3, but the cortical thickness of the bone did not change significantly. More anterior condyle positions in T1 and more posterior in T3.21 patients had at least 1 sign or symptom of TMD in T1 and 27 patients in T3. Four patients who were asymptomatic in T1 developed pain after surgery, 10 developed noises, 12 showed limited mouth opening, and 8 had abnormal opening patterns. It is concluded that more condylar posterior position after BSSRO and the reduction of condyle may be related to the enlargement of anterior space. The number of patients with joint symptoms increased postoperative, and the impact of BSSRO on TMD may be negative.

Effects of twin-block appliance on upper airway parameters in OSA children with class II malocclusion and mandibular retrognathia: a CBCT study.

Twin-block appliance had been advocated as a potential treatment option in paediatric obstructive sleep apnoea (OSA) due to their favourable effect in enhancing upper airway parameters and improving OSA symptoms. The aim of this study was to evaluate the effect of twin-block appliance therapy on upper airway parameters/dimensions and the apnoea-hypopnea indexes (AHIs) in OSA children with class II mandibular retrognathic skeletal malocclusion using cone-beam computed tomography. This prospective longitudinal study comprised 34 polysomnography-proven OSA growing children with class II mandibular retrognathic skeletal malocclusion between the ages of 8 and 12 years who had completed myofunctional twin-block therapy and matched corresponding controls. The upper airway was segmented into the nasopharynx, oropharynx, and hypopharynx, and the effect of twin-bock treatment on upper airway parameters/dimensions was assessed pre- and posttreatment using CBCT analysis, while a second standard overnight PSG was performed to determine changes in the AHI. At the nasopharynx level, minimal (nonsignificant) increases in all variables were observed within the twin-block group and between the groups (P > 0.05). At the level of the oropharynx, all variables increased significantly in the treatment group and between groups (P < 0.001), but these increases were nonsignificant in the control group. At the level of the hypopharynx, only the minimum cross-sectional area (MCA) increased significantly in the treatment group (P = 0.003). The change in MCA was also significant between the groups (P = 0.041). In addition, the upper airway length increased significantly in the twin-block group (P = 0.0154), and the AHI decreased by 74.8% (P < 0.001). CONCLUSION: Correction of class II mandibular retrognathic skeletal malocclusion with twin-block appliance resulted in a significant increase in upper airway volume, MCA, anteroposterior and lateral distances of the MCA at the level of the oropharynx, MCA at the level of the hypopharynx and upper airway length, and a significant decrease in AHI, but it had no effect on nasopharynx parameters. WHAT IS KNOWN: • CBCT imaging has been shown to be an effective and precise diagnostic tool for analyzing the upper airways and craniofacial structures. • Twin block appliance may be an effective treatment modality in children with OSA. WHAT IS NEW: • Minimal cross-sectional area of upper ways may be the most relevant potential parameter when explaining how the upper airway anatomy plays role of in the pathogenesis of pediatric OSA. • Twin block appliance induced favorable changes in upper airway morphology (oropharynx area mainly) and respiratory parameters in OSA children with class II malocclusion.