Assessing the immediate impact of Twin-block appliance insertion on adolescents' sleep using a wearable device.

OBJECTIVE: This prospective clinical study aimed to evaluate the immediate impact of Twin-block appliance insertion on the sleep of adolescents using a wearable device. MATERIALS AND METHODS: A total of 24 girls, aged 11-13 years, with Class II division 1 molar relationship, skeletal class 2 malocclusion (ANB ≥5) and overjet measuring ≥5 mm were selected. Exclusion criteria included a history of previous orthodontic treatment, systemic disease, irregular sleep pattern, obstructive sleep apnea, medical history of breathing disorders, or concurrent use of medications. Participants wore a wearable device to measure sleep parameters, including deep sleep, light sleep, minutes awake during sleep, wake-up times, bedtimes and total sleep times. The participants wore the device for 10 days prior to Twin-block insertion and sleep data were collected for another 10 days after insertion. RESULTS: Following the insertion of the Twin-block appliance, there was a highly statistically significant shift in bedtime and wake-up time to later hours (P < .001). All participants experienced a highly significant delay in bedtime compared to the recommended 10 pm time (P < .001). Additionally, there was a significant increase in the duration of light sleep (P < .05). However, the effect on deep sleep, minutes awake during sleep and sleep duration was not statistically significant. None of the sleep parameters tested showed statistically significant changes between the first 5 days after Twin-block insertion with the subsequent 5 days. CONCLUSION: The immediate insertion of the Twin-block appliance disrupts sleep onset, wake-up time and light sleep during the specified period of 10 days.

Effect of functional appliances on sleep-disordered breathing in Class II division 1 malocclusion children: Randomized controlled trial.

OBJECTIVES: A randomized controlled trial was undertaken to investigate the orthopaedic effect of functional appliances on the pharyngeal airway space and nocturnal breathing of children with skeletal class II due to mandibular retrusion. MATERIALS AND METHODS: Forty patients were randomized into a 1:1 ratio study (Twin block) group and a control (fixed appliance) group. Each group included equal numbers of boys and girls. Diagnosis with sleep-disordered breathing was not an inclusion criterion. The duration of the trial was 12 months (T0 - T12). Eligibility criteria included skeletal Class II division 1 malocclusion with mandibular retrognathism, SNA ≥82, SNB ≤78, ANB ≥4, overjet ≥6 mm, and patients in circumpubertal stage CVM2 and CVM3. The main outcomes were pharyngeal airway volume, oxygen desaturation index (ODI), and maximum expiratory pressure (MEP), while the secondary outcomes were skeletal and dental changes of the maxilla and mandible. Randomization was accomplished with random blocks of 20 patients with allocation concealed in sequentially numbered, opaque, and sealed envelopes. Blinding was only applicable for data analysis of radiographic measurements and data extracted from the pulse oximeter. RESULTS: The mean age of the patients was 10 ± 1.5 and 10 ± 1.2 at (T0) for the Twin Block and the control groups, respectively. The changes in the oropharyngeal (2.66 cc and 0.056; P = .03) and nasopharyngeal (1.3 cc and 0.84; P = .053) airway volumes for the Twin block and control groups, respectively, were significantly different for the oropharynx. There was a significant decrease in ODI by [median -3.55 (-5.05 to 0.50); P ≤ .001] and a significant increase [median 45 (0.0-110); P ≤ .001] in MEP for the Twin block group. A significant inverse correlation (r = -.589; P = .006) could be found between the total volume of the oropharynx and ODI. No serious harm was observed. CONCLUSIONS: The Twin block group showed significant change in oropharyngeal airway volume and improvement of nocturnal breathing. REGISTRATION: This trial was registered at https://www. CLINICALTRIALS: gov, registration number NCT04255511.

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.

Evaluation of modified clear Twin Block aligner in treating adolescents with skeletal class II malocclusion: A two-centre cephalometric study.

INTRODUCTION: The purpose of this study was to evaluate the therapeutic effect of modified clear Twin Block (CTB) aligner and traditional twin block (TB) appliance from skeletal, dentoalveolar and soft tissue changes in adolescents with skeletal class II malocclusion. METHODS: A total of 80 adolescents, included in this study from two medical centres, were distributed into CTB group, TB group and control group based on the treatment they received. Lateral cephalograms at pre-treatment (T1) and post-treatment (T2) were measured by modified Pancherz's cephalometric analysis, and dentoskeletal and soft tissue changes were analysed by independent-sample t-test, paired-sample t-test, ANOVA test and Scheffe's Post Hoc test. RESULTS: Seventy-five adolescents completed the study, including 32 in the CTB group, 32 in the TB group and 11 in the control group. Both CTB and TB treatment showed significant differences in most dentoskeletal and soft tissue measurements. Compared with the control group, improvements were observed in class II molar relationship through significant different in S Vert/Ms-S Vert/Mi in the CTB group (P < .01) and the TB group (P < .001), as well as deep overjet through significant different in S Vert/Is-S Vert/Ii in the CTB group (P < .001) and the TB group (P < .001). Besides, the CTB group also showed less protrusion of lower incisors and resulted in a more significant improvement in profile with fewer adverse effects on speaking, eating and social activities. CONCLUSIONS: For adolescents with skeletal class II malocclusion, CTB appliance was as effective as TB on improving dentoskeletal and soft tissue measurements, featuring more reliable teeth control and patient acceptance.

Three-dimensional evaluation of mandibular lingula: Comparisons of skeletal angle classifications and growth patterns.

OBJECTIVES: This study aimed to evaluate the position of the mandibular lingula (ML) in adult patients (aged between 18 and 35 years old) with different skeletal and growth patterns using cone-beam computed tomography (CBCT). DESIGN: Cross-sectional. SETTING: Dentistry department of University. SUBJECTS: Subjects comprised CBCT images of 150 adult patients, including 300 rami. METHODS AND MATERIALS: In total, 150 CBCT aged between 18 and 35 were selected and divided into three main groups of 50 samples based on their skeletal relationships (classes I, II and III). Patients were subdivided based on their growth pattern (vertical vs. horizontal), resulting in 25 samples per subgroup. Distances between the mandibular lingula and occlusal plane (ML-OP), sigmoid notch (ML-SN), external oblique ridge (ML-EOR), internal oblique ridge (ML-IOR), posterior border of the ramus (ML-PBR), inferior border of the ramus (ML-IBR), and horizontal and vertical distances to the mandibular foramen (ML-hMF and ML-vMF). One-way ANOVA variance analysis was employed to compare different angle classifications, and Bonferroni analysis was used for multiple comparisons. The Student's t-test was also used to compare growth patterns within each main group and genders within the subgroup. RESULTS: The study revealed statistically significant differences in the position of the mandibular lingula between different angle classifications, growth patterns, and genders. Class II samples showed a more anterior position of the ML, whereas Class III samples displayed a more posterior position of the ML. Patients with horizontal growth patterns and Angle Class III had a more posteriorly positioned ML. Gender differences were observed, particularly in Class I and Class III classifications, suggesting that gender may influence the variability of ML position in these specific classifications. CONCLUSION: The position of the mandibular lingula showed high variability among individuals with different angle classifications, growth patterns and genders.

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.

Impact of initial lip competence on the outcome of class II functional appliances therapy.

OBJECTIVES: The aim of this prospective clinical study was to evaluate the impact of initial lip position on class II functional appliance therapy. MATERIALS AND METHODS: In total, 34 class II division 1 patients (23 females, 19 males; mean age 12.4 ± 0.9 years) that met the inclusion criteria (> ½ class II molar relationship, overjet > 6 mm, ANB > 4°, neutral or horizontal growth pattern, cervical vertebral maturation stage (CVMS) II - III, mean wear-time > 10 h/day) were consecutively divided into two groups (lip incompetence (LI); lip competence (LC)). All patients were treated with the Sander bite jumping appliance (BJA). Wear time was microelectronically measured. Lateral cephalograms were taken at the beginning (T0) and after 1 year of treatment (T1). An untreated class II group served as a control (CG). Inter-group comparisons were determined with Mann-Whitney U tests for independent samples. RESULTS: Significant skeletal treatment effects were found in both treated groups when compared to the CG with significantly more pronounced mandibular skeletal effects in the LI than in the LC group (mandibular base length p < 0.001, composite mandibular base length p < 0.001, condylar head growth p = 0.002, co-pg p < 0.00, go-pg p = 0.003, reduction of the ANB angle p = 0.009, and Wits appraisal p < 0.001). CONCLUSION: The more pronounced mandibular effects in the LI group were composed of the functional orthopedic effect plus harmonization of the lip competence. CLINICAL RELEVANCE: Functional harmonization of lip incompetence with BJA enhances mandibular growth stimulation. Lip incompetence seems to impede mandibular growth and its harmonization seems to be a preventive approach.

The effectiveness of the total-maxillary-arch-distalization approach in treating class II division 1 malocclusion: A systematic review.

OBJECTIVE: The objective of this review is to assess the effect of total maxillary arch distalization (TMAD) treatment on the dental, skeletal, soft tissues, and airways during non-extraction camouflage treatment of class II division 1 patients. METHODS: We performed a systematic review of the published data in four electronic databases up to April 2023. We considered studies for inclusion if they were examining the effects of TMAD during treatment of class II division 1 malocclusion in the permanent dentition. Study selection, data extraction, risk of bias assessment, and assessment of the strength of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool were performed in duplicate. RESULTS: Out of the 27 articles that met the initial eligibility criteria, 19 studies were finally selected. Fair to relatively good quality evidence was identified after the risk of bias assessment of the included studies. Out of the 19 selected studies, 5 studies used inter-radicular TADs, 10 studies used modified C- palatal plate (MCPP), 3 studies used infra zygomatic crest (IZC) TADs, 1 study compared buccal TADs versus MCPP, and 1 study compared between cervical headgear and MCPP. The maximum amount of maxillary arch distalization using buccal TADs, MCPP, IZC TADs, and headgear was 4.2mm, 5.4mm, 5mm, and 2.5mm respectively. Different results regarding the amount of dental, skeletal, and soft tissue changes were observed. CONCLUSIONS: The current low to very low certainty level of evidence suggests that TMAD is effective in camouflaging class II division 1 malocclusion. Future well-conducted and clearly reported randomized controlled trials that include a control group are needed to make robust recommendations regarding the effect of TMAD with different appliances on dental, skeletal, and soft tissue structures. CLINICAL RELEVANCE: TMAD should be given priority with caution in class II patients who refuse the extraction of premolars. TMAD may be considered an adjunctive approach to solve cases associated with high anchorage need or anchorage loss.

Noninvasive conservative management of anterior open bite treated with TADs versus clear aligner therapy.

OBJECTIVES: Anterior open bite can be treated non-surgically via molar intrusion using temporary skeletal devices (TAD). Clear aligner therapy (CAT) is recognized as a viable therapeutic modality for non-extraction treatment of adults with mild open bite. This study aimed to compare the treatment effect and mechanisms of open bite closure between patients treated with braces and TADs double arch intrusion and those treated with CAT. Treatment success at T3 was based on 1- positive overbite on ceph; 2- Change in the vertical dimension 3- post treatment POSI score equal to zero. MATERIAL AND METHODS: The TAD group includes 18 consecutively treated patients from the main author. The CAT group consisted of 16 selected patients from three different orthodontists. The observation time points were as follows: pretreatment (T1), end of molar intrusion and positive overbite achieved (T2), end of treatment (T3), at least 6-month follow-up (T4). Treatment changes were assessed by cephalometric analysis and frontal intraoral photo. RESULTS: At the end of treatment, 100% of the patient of the TAD group and 78,6% of the CAT group had a posi score of 0. The TAD group showed a significant reduction in vertical measurements (SN-MPA: -1,55° ± 0.41, LAFH: -3,05 ± 0.51 mm, U6-PP: -1.48 ± 0.30 mm), but the CAT group did not have significant changes for these variables. Both groups had significant increases in overbite from T1 to T3 (TAD: 4,32 ± 0,5 mm; CAT: 2,33 ± 0.56 mm), and overbite remained stable at T4. The CAT group did not have a significant upper molar intrusion, but a significant extrusion of 1.22 ± 0.42 mm of the lower incisor occurred. CONCLUSION: The TAD group achieved bite closure by upper molar intrusion, lower molar and incisors vertical control, and mandibular plane counterclockwise rotation, resulting in an improved AP and vertical relationship. The CAT group achieved bite closure through the lower incisor extrusion without significant change in the vertical dimension. CLINICAL RELEVANCE: This study provides relevant information about the skeletal and dental changes of open bite treatment with TADs double arch intrusion. The comparison with a control group treated with CAT confirms known information.

Orthodontic correction of acquired open bite with TMJ degeneration: A retrospective study of outcomes and stability.

BACKGROUND/PURPOSE: Newly developed temporary anchorage devices (TADs) serve a strong orthodontic anchorage to intrude molars for correction of anterior open bite (AOB). We measured cephalometric changes in skeletal open bite patients which developed subsequently to temporomandibular joint disorders with bilateral point contacts at terminal molars. METHODS: We retrospectively recruited 32 patients who had been treated their TMD before orthodontic correction (overbite: -3.14 ± 1.86 mm). Partial orthodontic appliances were used to intrude posterior teeth using TADs until positive OB obtained (T1). Full fixed appliances were then used to achieve proper overjet and overbite (T2). We collected lateral cephalograms before (T0), during (T1) and after (T2) treatment, and at follow-ups (T3). Using ANOVA, we analyzed the differences among these time points to determine treatment changes and stability of orthodontic results. RESULTS: In this group predominantly comprising young adult women, orthodontic treatment with TADs significantly reduced upper posterior dental heights (T2-T0:-1.84 ± 0.66 mm) and facilitated the retraction and uprighting upper incisors (T2-T0: -9.92 ± 1.72°), to achieve appropriate OJ (T2-T0: -3.21 ± 0.49 mm) and OB (T2-T0: 4.10 ± 0.28 mm) with p < 0.05. Except upper posterior dental height, most of cephalometric changes including OJ, OB, and upper incisal axis remained significant at follow-ups with retention time of 3.7 ± 2.6 years. Only three out of 30 patients experienced small amount of open bite at T3. CONCLUSION: Orthodontic correction of OJ remained relatively stable among 90 % of patients with TMJ degeneration by intrusion via TADs. This modern but conservative orthodontic approach can improve occlusal functions in skeletal open bites.

Thematic Analysis of Parental Experiences of Patients' Orthognathic Surgery.

Orthognathic surgery often requires extensive orthodontic preparation and a prolonged postoperative recovery that can be stressful for patients and their families. Parents are a primary source of support for patients; accordingly, a better understanding of the parents' experience of orthognathic surgery can help inform clinical care. Using a prospective cross-sectional qualitative study design, 4 focus groups (2 English and 2 Spanish; mean length 65 min) were held with parents of patients who had completed orthognathic surgery for class II/III malocclusion. Thematic content analysis of the group transcriptions was conducted. Participants were 10 mothers and 3 fathers of 12 children (50% with cleft lip/palate) ages 17 to 23 who completed LeFort I (41.7%), LeFort I with bilateral sagittal split osteotomy (BSSO; 41.7%), or BSSO (16.7%) within the prior 3 to 16 months. Themes fit within a chronological framework: (1) Preparing for Surgery included their larger health context, anticipating surgery, surgery preparation by team and family, and religious faith; (2) Challenges after Surgery consisted of complications, pain, frustration, nutritional challenges, parental anxiety, activity changes, sleep, breathing issues, swelling, and unanticipated aspects of surgery; and (3) Supports after Surgery were nutritional support, appreciation of medical team, postoperative improvements, appearance changes, communicating, supporting patient, and patient coping. Parents also offered advice for families and medical teams. Surgeons and other providers who are part of orthognathic surgical preparation can implement recommendations based on parental experiences to increase patient and family readiness for surgery by providing early education, assisting with advocacy, focusing on nutrition, and supporting coping.

Surgery-first in interdisciplinary class II cases.

OBJECTIVES: To present an interdisciplinary case treated with a surgery-first orthognathic approach, followed by orthodontic and prosthodontic treatment. CLINICAL CONSIDERATIONS: After an accurate pre-operative virtual planning, a young patient with skeletal class II, retrognathia, and an anterior open bite was treated with bimaxillary orthognathic surgery without pre-surgical orthodontic decompensation. Orthodontic treatment was carried out post-operatively. The treatment was completed with a prosthodontic phase to improve the final esthetic outcome of the smile. CONCLUSIONS: A surgery-first approach allowed to achieve esthetic and functional results in a reduced treatment duration that remained stable over the course of 1 year. The outcomes were consistent with prior research in terms of advantages brought by following an accurately planned surgery-first protocol. Nevertheless, longer-term follow-up was required to evaluate the treatment stability. CLINICAL SIGNIFICANCE: An accurately planned surgery-first approach significantly helped in shortening the duration of the treatment, while providing a stable, functional, and esthetic solution to the patient's problems.

An automated method for assessing condyle head changes in patients with skeletal class II malocclusion based on Cone-beam CT images.

OBJECTIVES: Currently, there is no reliable automated measurement method to study the changes in the condylar process after orthognathic surgery. Therefore, this study proposes an automated method to measure condylar changes in patients with skeletal class II malocclusion following surgical-orthodontic treatment. METHODS: Cone-beam CT (CBCT) scans from 48 patients were segmented using the nnU-Net network for automated maxillary and mandibular delineation. Regions unaffected by orthognathic surgery were selectively cropped. Automated registration yielded condylar displacement and volume calculations, each repeated three times for precision. Logistic regression and linear regression were used to analyse the correlation between condylar position changes at different time points. RESULTS: The Dice score for the automated segmentation of the condyle was 0.971. The intraclass correlation coefficients (ICCs) for all repeated measurements ranged from 0.93 to 1.00. The results of the automated measurement showed that 83.33% of patients exhibited condylar resorption occurring six months or more after surgery. Logistic regression and linear regression indicated a positive correlation between counterclockwise rotation in the pitch plane and condylar resorption (P < .01). And a positive correlation between the rotational angles in both three planes and changes in the condylar volume at six months after surgery (P ≤ .04). CONCLUSIONS: This study's automated method for measuring condylar changes shows excellent repeatability. Skeletal class II malocclusion patients may experience condylar resorption after bimaxillary orthognathic surgery, and this is correlated with counterclockwise rotation in the sagittal plane. ADVANCES IN KNOWLEDGE: This study proposes an innovative multi-step registration method based on CBCT, and establishes an automated approach for quantitatively measuring condyle changes post-orthognathic surgery. This method opens up new possibilities for studying condylar morphology.

Treatment change comparisons between skeletal Class I and II white adolescents with 3 different vertical divergencies-Part 2: Holdaway difference.

INTRODUCTION: The Holdaway difference represents the relationship of the NB line to the mandibular incisor (NB-L1) and the bony pogonion (NB-Pog). This study aimed to evaluate treatment changes of NB-L1, NB-Pog, and the Holdaway difference in patients with skeletal Class I and II relationships with 3 different skeletal divergencies. METHODS: This retrospective study was the second part of treatment outcome assessments of 135 white adolescent patients (females, n = 69; males, n = 66; mean age, 12.8 ± 1.4 years pretreatment and 15.0 ± 1.4 years posttreatment). The NB-L1, NB-Pog, and Holdaway differences (NB-L1 - NB-Pog) were measured. The mixed-model analysis of variance was used to assess within- and between-subject effects responding to horizontal and vertical skeletal discrepancies. RESULTS: For the group with favorable profile changes, the means of the Holdaway difference were maintained in the hypodivergent and normodivergent subgroups and reduced in the hyperdivergent subgroups for patients with skeletal Class I and II relationships. The means of NB-L1 and Holdaway difference were significantly larger in the skeletal Class II group and became greater as skeletal vertical divergencies increased. The NB-Pog means were significantly different only between the hypodivergent and hyperdivergent subgroups. CONCLUSIONS: Based on the findings of this study, the Holdaway difference should be adjusted to individualize the incisor positions, considering not only the anteroposterior but also the vertical skeletal relationships of the patients.

Treatment of Class II malocclusion with 2-maxillary premolar extractions: Monthly vs biweekly appointments, which is more efficient?

INTRODUCTION: This study compared whether there is a difference in treatment time (TT) and efficiency when appointments are held once a month or at 2-week intervals in patients with Class II malocclusion treated with 2-premolar extractions METHODS: The patients of this retrospective sample were treated with the same orthodontic mechanics and divided into 2 groups according to frequencies of orthodontic appointments. Group 1 consisted of 18 patients (10 males, 8 females), with an initial mean age of 14.38 ± 1.38 years and appointments once a month. Group 2 consisted of 19 patients (9 males, 10 females), with an initial mean age of 14.12 ± 1.38 years and biweekly appointments. Edgewise fixed appliances with a slot size of 0.022 × 0.028 mm were used, and the anterior teeth were retracted en-masse with a rectangular wire and elastic chains. The Peer Assessment Rating and Objective Grading System indexes were measured in the dental models at the beginning and the end of treatment. Efficiency was assessed by dividing the percentage of improvement of each occlusal index concerning the multiplication of TT and the number of appointments. RESULTS: Both groups presented similar Peer Assessment Rating and Objective Grading System indexes at the end of treatment. Groups 1 and 2 presented different TTs (28.06 and 22.05 months, respectively); however, there were no differences regarding the efficiency of both protocols. CONCLUSIONS: Patients with Class II malocclusion treated with 2-maxillary premolars had significantly shorter treatment times when seen on biweekly appointments than those with monthly appointments; however, there was no difference in efficiency between protocols.

A comparison of skeletal and dental changes in patients with a Class II relationship treated with clear aligner mandibular advancement and Herbst appliance followed by comprehensive orthodontic treatment.

INTRODUCTION: The objective of this study was to compare the skeletal and dental changes of patients with a Class II relationship treated with clear aligner mandibular advancement (MA) and Herbst appliances followed by comprehensive orthodontic treatment. METHODS: The participants included 20 patients treated with MA and 20 with the Herbst appliance. Orthodontic records were taken before treatment, after the functional appliance, and completion of phase II treatment. The skeletal and dental changes across the 3-time periods were evaluated using a matched paired t test for each treatment. A 2-sample t test was used to examine the changes across periods between 2 treatment groups (P <0.05). RESULTS: Significant reduction in overjet, overbite, and change in molar relationship were obtained by both appliances with similar skeletal and dental contributions. This was contributed by a forward movement of the mandible and mandibular molars, backward movement of the maxillary molars, and retraction of the maxillary incisors. After phase II treatment, both appliances could maintain the skeletal and dental changes achieved during the advancement phase. Greater change in overbite (2.4 mm vs 1.4 mm), an eruption of maxillary incisors (0.9 mm vs 0.1 mm), and proclination of mandibular incisors were found with the Herbst group (3.9° vs -2.1°). The average total treatment time was similar with the 2 appliances. CONCLUSIONS: Both functional appliances were equally effective in reducing the overjet and overbite and achieving a Class I molar relationship with a similar length of treatment time. The Herbst design lacked control of the mandibular incisor proclination, and clear aligners offered better vertical control and management of the mandibular incisor inclination.

Clinical efficacy of the Invisalign mandibular advancement appliance: A retrospective investigation.

INTRODUCTION: This retrospective investigation aimed to determine whether the achieved changes in the treatment of Class II malocclusion were the same as those planned after the prescribed wear of an initial phase of Invisalign treatment with the mandibular advancement appliance (MAA) (Align Technology, Santa Jose, Calif). METHODS: All patients treated with the MAA and who satisfied inclusion/exclusion criteria were selected from a database of 16,500 patients treated with clear aligners by 16 orthodontists. The pretreatment, planned, and achieved overjet measurements were documented from data provided in Align Technology's software facility, ClinCheck. Changes in intermaxillary anteroposterior (AP) first permanent molar (FPM) relationships were evaluated using Geomagic Control X (3D systems, Rock Hill, SC) metrology software. RESULTS: Most of the 195 patients who satisfied the inclusion criteria were females (n = 104; 53.3%). The mean age was 12.62 ± 2.20 years. The pretreatment overjet was reduced from 6.49 ± 2.86 mm to 4.61 ± 2.22 mm after prescribed MAA wear, which was 42.5% of the planned outcome. The pretreatment AP FPM reduced from 3.14 ± 1.95 mm to 2.24 ± 2.51 mm, which was 31.3% of that planned. Thirty-eight (19.5%) patients experienced an increase in overjet where a reduction was planned. CONCLUSIONS: Less than half of the planned overjet reduction and less than a third of the planned AP FPM correction were achieved with the MAA. Almost 20% of patients completed the MAA phase of treatment with an increased overjet despite a reduction being planned.

Exploring long-term changes and influencing factors of the upper airway in patients with a skeletal Class II relationship after mandibular advancement with maxillary setback surgery: A comprehensive 2-year follow-up investigation.

INTRODUCTION: The objective of this study was to investigate the 2-year postoperative change and influencing factors of the upper airway after mandibular advancement with maxillary setback surgery for patients with a skeletal Class II relationship. METHODS: Fifty-seven participants who underwent mandibular advancement with maxillary setback surgery were enrolled consecutively. Cone-beam computed tomography was performed preoperatively, 3 months postoperatively (T1), and 2 years (T2) postoperatively. All parameters were measured using Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif). RESULTS: The total volume (V), minimum cross-sectional area (CSAmin), and glossopharynx increased significantly in both the short-term (V, 13.33%; CSAmin, 33.03%; glossopharynx, 26.73%) and long-term (V, 10.19%; CSAmin, 23.18%; glossopharynx, 18.27%) after the surgery. Mandibular advancement, mandibular width increase, preoperative CSAmin, and body mass index (BMI) significantly affected 2-year postoperative V increases. Mandibular advancement and BMI significantly affected 2-year postoperative glossopharynx increases. Backward movement of point PNS may lead to a reduction of the nasopharynx; however, downward movement of point PNS, upward movement of point A, and increased maxillary width may compensate for this effect by increasing the likelihood of the nasopharynx opening. Furthermore, mandibular body length at T1 is positively associated with relapse rate ([T2 - T1] / T1) of V and CSAmin. CONCLUSIONS: Mandibular advancement amount, mandibular width increase, preoperative CSAmin, and BMI are the 4 factors for long-term V changes. Patients with a longer mandibular body length might have a lower relapse rate.

Smile attractiveness in patients treated with or without 4 premolar extractions: A 36-year follow-up.

INTRODUCTION: This study aimed to assess the smile attractiveness in patients treated with or without 4 premolar extractions at a 36-year follow-up. METHODS: The sample comprised 52 patients with Class I and II malocclusion divided into 2 groups. Group 1 consisted of 15 patients treated without extractions (10 females and 5 males), with a mean pretreatment, posttreatment, and long-term posttreatment (T3) age of 13.2, 15.1, and 49.8 years, respectively. The mean treatment time was 1.9 years, and the mean long-term follow-up period was 34.7 years. Group 2 consisted of 37 patients (25 females and 12 males) treated with 4 premolar extractions, with a mean pretreatment, posttreatment, and long-term posttreatment age of 13.3, 15.7, and 53.6 years, respectively. The mean treatment time was 2.3 years, and the mean long-term follow-up period was 37.9 years. The mean retention time was 2 years for both groups. Frontal smiling photographs were obtained at long-term follow-up. Smile attractiveness was evaluated in an online questionnaire in which the evaluator could rate the smiling photographs with a 10-point scale. The randomly selected evaluator sample consisted of 62 laypeople, 33 dentists, and 89 orthodontists. Independent t tests, 1-way analysis of variance, and Tukey tests were used for intergroup comparisons at P <0.05. RESULTS: The smile attractiveness on the long term was similar in the groups treated with 4 premolar extractions (4.70 ± 1.35) or without extractions (4.51 ± 1.46). Women and orthodontists were more critical in assessing smile attractiveness than men, dentists, and laypeople. CONCLUSIONS: After long-term posttreatment, the smile attractiveness was similar in patients treated with 4 premolar extractions or without extractions.

Long-term profile attractiveness of patients with Class I and II malocclusion treated with and without extractions: A 35-year follow-up.

INTRODUCTION: The objective of this study was to compare the profile attractiveness in subjects treated with and without extractions after the long-term 35-year follow-up, according to laypeople, dentists, and orthodontists. METHODS: A total of 40 patients with Class I and II malocclusion were divided into 2 groups, according to the treatment protocol: extraction (E) group, extractions of 4 premolars (n = 24), with mean pretreatment (T1), posttreatment (T2), and long-term posttreatment (T3) ages of 13.13, 15.50 and 49.56 years, respectively. The mean treatment time (T2 - T1) was 2.37 years, and the long-term follow-up (T3 - T2) was 34.19. Nonextraction (NE) group (n = 16), with mean ages at T1, T2, and T3 of 13.21, 15.07, and 50.32 years, respectively. The mean (T2 - T1) was 1.86 years, and the (T3 - T2) was 35.25 years. Lateral cephalograms were used to perform profile facial silhouettes, and an online evaluation was performed by 72 laypeople, 63 dentists, and 65 orthodontists, rating the attractiveness from 1 (least attractive) to 10 (most attractive). The intragroup comparison was performed with the repeated measures analysis of variance and Tukey tests. Intergroup comparison was performed with t tests, 1-way analysis of variance, and Tukey tests. RESULTS: The E group had a longer treatment time than that of the NE group. In the pretreatment, posttreatment, and long-term posttreatment stages, the E and NE groups showed similar profile attractiveness. Laypersons and dentists were more critical than orthodontists. CONCLUSIONS: At long-term posttreatment follow-up, profile attractiveness was similar in patients treated with and without extractions.