Sleep disruption and premolar absence, NHANES, 2017-2020: A cross-sectional study.

OBJECTIVE: Orthodontic treatment often involves four first premolar extractions. There is concern that the retraction of the anterior teeth due to extraction of first premolars may constrict tongue space and will reduce oral cavity and oropharynx space. Constricted airways are often associated with sleep disordered breathing (SDB) and sleep disruption. The aim of this study was to determine if there is an association of SDB factors with the absence of first premolars. METHODS: A cross-sectional study was conducted using National Health and Nutrition Examination Survey (NHANES) 2017-March 2020 data on participants, aged 18-65 years (n = 4742). Variables of interest included self-reports of SDB (symptoms of disrupted sleep such as snoring, snorting, daytime sleepiness, and inappropriate number of hours of sleep). Data for the presence/absence of first premolars were gathered from the oral examination section of NHANES. An assumption was made that absence of four first premolars in dentate participants indicated extractions for orthodontic treatment. Data analyses were conducted with Rao Scott chi squared test. RESULTS: There were no significant associations of SDB and symptoms of disrupted sleep associated with the absence of four first premolars in dentate participants. CONCLUSION: Concerns of the impact of first premolar extractions on SDB were not supported with this study.

Comparison of treatment effects between clear aligners and fixed appliances in patients treated with miniscrew-assisted molar distalization.

OBJECTIVES: The biomechanics in achieving molar distalization may differ between fixed appliances and clear aligners in the control of tooth movement. The objective of this study was to compare the treatment effects between clear aligners (CA) and fixed appliances (FA) in patients treated with miniscrew-assisted molar distalization. METHODS: The sample consisted of 46 subjects with mild-to-moderate crowding. A total of 22 patients treated with clear aligners (age, 25.66 ±â€…6.11 years old) and 24 patients treated with fixed appliances (age, 24.04 ±â€…4.95 years old) for miniscrew-assisted molar distalization were included in this study. The dental and skeletal changes were evaluated by the pre- and post-treatment lateral cephalograms. RESULTS: Significant changes were found with the vertical variables SN-OP angle (2.24 ±â€…3.22°, P < .05) and SN-MP angle (0.73 ±â€…1.15°, P < .05) for the FA group when compared with the CA group (SN-OP angle 0.41 ±â€…2.26° and SN-MP angle -0.21 ±â€…1.38°, P > .05). Both treatment groups achieved a 2-3 mm. molar distalization with significant intrusion of the upper molars. The CA group showed significantly less distal tipping of molars (U6^PP angle -2.29 ±â€…3.29° and L6^MP angle -2.92 ±â€…2.49°, P < .05) compared to the FA group (-5.24 ±â€…4.28° and -5.53 ±â€…5.03°, P < .05). In addition, significant retraction and lingual inclination of the upper and lower incisors were found in both groups. LIMITATIONS: The changes of tooth position were evaluated by 2D lateral cephalograms, not 3D measurements. CONCLUSIONS: Compared to fixed appliances, clear aligners seemed to have better control of vertical dimension and distal tipping of molars in patients treated with miniscrew-assisted molar distalization.

White spot lesion-related perception of aesthetics and treatment satisfaction among orthodontic patients, orthodontists and other dental specialists.

OBJECTIVE: To investigate the impact of various degrees of white spot lesions (WSLs) of maxillary anterior teeth on the aesthetic perception and treatment satisfaction among orthodontic patients, orthodontists and other dental specialists and to evaluate the differences among the three groups. METHODS: A total of 45 orthodontic patients (OP), 45 orthodontists (OR) and 45 other dental specialists (OS) were recruited. Subjective evaluations of perceived aesthetics and treatment satisfaction were performed towards eight digitally generated photographs of maxillary anterior teeth with incremental degrees of WSLs using a numerical visual analogue scale (VAS) from 0 to 100. Data were collected and analysed with descriptive statistics, repeated one-way analysis of variance and multivariable generalized estimating equations. RESULTS: A total of 135 valid questionnaires were collected. Regarding aesthetic scores for WSLs, OP gave more positive scores than OR and OS (p < .05) towards excessive white spot formation without colouration and were more tolerant than OR (p < .05) towards excessive white spot formation with slight colouration. The level of treatment satisfaction for slight to severe WSLs without cavitation was higher in OP than OR. Patients with higher education levels had more negative scores for aesthetic perception and treatment satisfaction (p < .05). Patients who brushed teeth more frequently scored lower in treatment satisfaction (p < .05). CONCLUSIONS: Orthodontists were the most critical when evaluating aesthetics and treatment satisfaction for slight to severe WSLs without cavitation. For orthodontic patients, better oral hygiene habits and higher education levels were associated with more critical attitudes towards WSLs.

THE USE OF DENTAL PATIENT-REPORTED OUTCOMES AMONG COMPARATIVE OBSERVATIONAL STUDIES IN ORTHODONTICS: A METHODOLOGICAL STUDY.

OBJECTIVE: To identify and summarize the presence and characteristics of dental patient-reported outcomes (dPROs) and dental patient-reported outcome measures (dPROMs) within comparative observational studies published in 5 leading orthodontic journals. METHODS: Electronic searching was performed to identify intervention (therapeutic or preventive) related comparative observational studies published in selected journals between 2015 and 2021. Two authors extracted the characteristics of each included study independently and in duplicate and summarized the dPROs and dPROMs used in these studies. All dPROs were classified into 2 general types (oral health-related quality of life [OHRQoL] and others), while dPROMs were divided into 3 categories (single-item questionnaires, generic multiple-item questionnaires, and specific multiple-item questionnaires). In addition, dPROMs were examined, if they evaluated the 4 dimensions of OHRQoL (oral function, orofacial pain, orofacial appearance, and psychosocial impact). RESULTS: A total of 683 observational studies were eligible and included of which 117 (17.1%) used dPROs and dPROMs. Seven different dPROs (OHRQoL, patients' satisfaction with treatment, preferences, concerns, compliance, duration, and unwanted events) and 33 different dPROMs (including 8 single-item questionnaires, 11 generic multiple-item questionnaires, and 14 specific multiple-item questionnaires) were identified in these studies. OHRQoL was the most commonly used dPRO (92/117, 78.6%), while Oral Health Impact Profile 14 (OHIP-14) was the most frequently used dPROM (20/92, 21.7%). In terms of study design, cross-sectional studies had the highest proportion of dPRO usage (62/148, 41.9%), followed by cohort studies (63/505, 12.5%) and case-control studies (1/30, 3.3%). CONCLUSIONS: Only one-sixth of comparative observational studies published in leading orthodontic journals could reflect patients' perspectives. Observational studies in orthodontics need to provide more patient-important information through the use of dPROs and dPROMs.

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.

Association between adenotonsillar hypertrophy and dentofacial characteristics of children seeking for orthodontic treatment: A cross-sectional study.

OBJECTIVE: To compare the dentofacial characteristics of children with and without adenoid and/or tonsillar hypertrophy. METHODS: A consecutive sample of orthodontic patients aged 6-12 that took pre-treatment lateral cephalograms were included in this study. Those with history of previous orthodontic treatment, adenoidectomy or tonsillectomy, or craniofacial anomalies were excluded. The diagnosis of adenoid and tonsillar hypertrophy was based on Fujioka's and Baroni's methods, according to which the subjects were divided into four groups: the adenoid hypertrophy only (AHO) group; tonsillar hypertrophy only (THO) group; combined adenoid and tonsillar hypertrophy (AH+TH) group; and no adenoid or tonsillar hypertrophy (NH) group. Cephalograms were used for skeletal and dental measurement. Data were analyzed using one-way ANOVA, LSD post-hoc tests and Chi-square test. RESULTS: A total of 598 patients were included. Compared with the NH group, the THO group had significantly larger SNB angle (P < 0.001), as well as significantly smaller ANB angle (P<0.001) and Wits value (P = 0.001). The U1-L1 angle of AHO group was significantly smaller than that in the NH group (P = 0.035). The proportion of adenoid hypertrophy in Class II patients was significantly higher than that in Class III patients (P = 0.001). The proportion of tonsillar hypertrophy in Class III patients was significantly higher than that in Class I patients (P < 0.001) and Class II patients (P < 0.001). CONCLUSION: Over 80 % of children seeking orthodontic treatment had either adenoid or tonsillar hypertrophy. Children with adenoid hypertrophy tend to have skeletal Class II malocclusion, while those with tonsillar hypertrophy tend to have skeletal Class III malocclusion.

Role of the tonsil-oropharynx ratio on lateral cephalograms in assessing tonsillar hypertrophy in children seeking orthodontic treatment.

OBJECTIVES: To analyze the diagnostic value of the tonsil-oropharynx (T/O) ratio on lateral cephalograms for evaluating tonsillar hypertrophy (TH). METHODS: A cross-sectional study was performed on 185 consecutive children (101 males, 84 females; mean age 7.3 ± 1.4 years) seeking orthodontic treatment. The T/O ratios on lateral cephalograms were calculated following Baroni et al.'s method. Tonsil sizes were clinically determined according to the Brodsky grading scale. Spearman correlation coefficients between the T/O ratio and clinical tonsil size were calculated with the total sample and subgroups and then compared between subgroups. Diagnostic value was analyzed using the receiver operating characteristic (ROC) curve, sensitivity, specificity, positive and negative predictive values, and accuracy. RESULTS: There was a strong correlation between the T/O ratio and clinical tonsil size in children (ρ = 0.73; P < 0.001). A significantly higher correlation coefficient was found in the Class III children. The ROC curve revealed an area under the curve of 0.90 (95% CI, 0.86-0.94; P < 0.001). The optimal cutoff value of the T/O ratio for predicting TH was 0.58, with a sensitivity of 98.7% and specificity of 64.2%. Employing the cutoff value of 0.5, the sensitivity was 100% and the specificity was 45.9%. CONCLUSIONS: Measurement of the T/O ratio on lateral cephalograms may be helpful to initial screening in children for TH. Practitioners may combine the clinical examination of tonsil size with the cephalometric findings for a more comprehensive evaluation.

Obstructive sleep apnea-related knowledge, attitude, experience, and behaviors among orthodontic professionals: a survey.

PURPOSE: To assess obstructive sleep apnea (OSA)-related experience, knowledge, attitude, and behaviors among orthodontic professionals in China and identify factors associated with their knowledge levels, attitude toward referring, and self-confidence in the management of patients with OSA. METHODS: An online cross-sectional survey was conducted using a 31-item questionnaire developed with a professional online survey tool ( www.wjx.cn ) and distributed via WeChat (Tencent, Shenzhen, China). Data were collected between January 16 and 23, 2022 and analyzed using the chi-square test, Fisher's exact test, and multivariate generalized estimation equations. RESULTS: A total of 1760 professionals responded to the survey, and responses to 1611 questionnaires were valid. The average score of correct answers to the 15 OSA knowledge questions was 12.1 ± 2.0. Most of the professionals agreed that it was necessary to identify patients who might have OSA in practice. The top three sources for gaining knowledge of OSA according to the survey were classrooms and textbooks (76.3%), medical lectures (75.7%), and academic conferences (73.2%). The level of knowledge was significantly correlated with self-confidence in treatment (P < 0.001) and willingness to refer patients to otolaryngologists or clinicians of related disciplines (P < 0.001). CONCLUSIONS: Most orthodontic professionals agreed that there was a need to identify patients with OSA and learn further about related problems. Treatment confidence and willingness of professionals to refer patients were related to the level of OSA knowledge. These findings suggest that promotion of OSA-related education may help improve the care of patients with OSA.

The dental and craniofacial characteristics among children with obstructive sleep apnoea: a systematic review and meta-analysis.

BACKGROUND: Paediatric obstructive sleep apnoea (OSA) is a sleep breathing disorder which may have dramatic effects on childhood behaviour, neurodevelopment, metabolism, and overall health in children. Malocclusion and craniofacial morphology may be related to paediatric OSA, and therefore provide information for clinicians to recognize, evaluate and treat patients with this sleeping disorder. OBJECTIVE: The aim of this systematic review was to summarize evidence regarding the association between paediatric OSA and children's dental and craniofacial characteristics. SEARCH METHODS: PubMed, Embase, and Cochrane Central Register of Controlled Trials were searched from inception to 1 June 2022. SELECTION CRITERIA: Cross-sectional studies, comparing dental or craniofacial characteristics using clinical dental examinations or radiographic findings between OSA children (less than 18 year, diagnosed with overnight polysomnography) and healthy children, were included. DATA COLLECTION AND ANALYSIS: The Joanna Briggs Institute Critical Appraisal Checklist for Analytical Cross-Sectional Studies was used to assess the quality of included studies. RevMan software was used for performing the Meta-analyses. RESULTS: Sixteen studies were included. Meta-analyses showed that the overjet (MD = 0.86, 95% CI: 0.20 to 1.51; P = 0.01), the saggital skeletal jaw discrepancy (ANB; MD = 1.78, 95% CI: 1.04 to 2.52; P < 0.00001) and mandibular plane angle (FH-MP; MD = 3.65, 95% CI: 2.45 to 4.85; P < 0.00001) were greater in OSA-affected children. In contrast, the upper molar arch width (upper first deciduous molar width; MD = -1.86, 95% CI: -3.52 to -0.20; P = 0.03), (Upper second deciduous molar width; MD = -1.06, 95% CI: -1.88 to -0.24; P = 0.01), SNB (MD = -2.10, 95% CI: -3.11 to -1.09; P < 0.0001), and maxillary length (ANS-PNS; MD = -1.62, 95% CI: -2.66 to -0.58; P = 0.002) were smaller in the OSA group. CONCLUSIONS: This review shows that OSA-affected children tend to present with mandibular retroposition or retrognathia, increased mandibular plane angle and excess anterior overjet. However, these findings need to be viewed with caution as the corresponding differences may not be significant clinically. REGISTRATION: PROSPERO (CRD42020162274).

THE USE OF DENTAL PATIENT-REPORTED OUTCOMES AMONG RANDOMIZED CONTROLLED TRIALS IN ORTHODONTICS: A METHODOLOGICAL STUDY.

OBJECTIVE: To identify and summarize the use and characteristics of dental patient-reported outcomes (dPROs) and dental patient-reported outcome measures (dPROMs) within randomized controlled trials (RCTs) published in 5 leading orthodontic journals. METHODS: A manual search was conducted to identify intervention (therapeutic or preventive) related RCTs published in selected journals between 2015 and 2021. Two authors extracted the characteristics of each included trial, as well as all outcomes and outcome measures used in these trials independently and in duplicate. Thereafter, the use of dPROs and dPROMs was identified and summarized. We classified all dPROs into 2 general types (oral health-related quality of life [OHRQoL] and others) and dPROMs into 3 categories (single-item questionnaires, generic multiple-item questionnaires, and specific multiple-item questionnaires). We also identified whether these dPROMs assessed 4 dimensions of OHRQoL (Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact). RESULTS: From 4631 examined articles, a total of 315 RCTs were included, of which 76 (24.1%) used dPROs and dPROMs. Eight different dPROs (OHRQoL, patients' satisfaction with treatment, difficulty, compliance, preference, efficacy, duration, and unwanted events) and 34 different dPROMs (including 13 single-item questionnaires, 7 generic multiple-item questionnaires, and 14 specific multiple-item questionnaires) were identified in these trials. OHRQoL was the most commonly used dPRO (n = 71; 93.4%), followed by patients' satisfaction with treatment (n = 10; 13.2%), patient-reported difficulty (n = 5; 6.6%), and patient-reported compliance (n = 4, 5.3%). The 4 most frequently used dPROMs were pain measured with 10 mm Visual Analogue Scale (n = 20; 24.1%), pain measured with Numerical Rating Scale (n = 11; 13.3%), the Feldmann's Questionnaire (2007) (n = 6; 7.2%), and the Oral Health Impact Profile 14 (n = 5; 6.0%). CONCLUSION: Only about one-fourth of RCTs published in leading orthodontic journals can reflect patients' perspectives. OHRQoL was the most commonly used dPRO in these trials. Substantial heterogeneity exists among dPROMs used for OHRQoL assessment. Efforts are needed from researchers, reviewers, editors and other stakeholders to promote the wide and standardized use of dPROs in orthodontic research.

Three-dimensional comparison of bone-borne and tooth-bone-borne maxillary expansion in young adults with maxillary skeletal deficiency.

OBJECTIVE: To compare the transverse dental and skeletal changes in patients treated with bone-anchored palatal expander (bone-borne, BB) compared to patients treated with tooth and bone-anchored palatal expanders (tooth-bone-borne, TBB) using cone-beam computer tomography (CBCT) and 3D image analysis. METHODS: The sample comprised 30 patients with transverse maxillary discrepancy treated with two different types of appliances: bone-borne (Group BB) and tooth-bone-borne (Group TBB) expanders. CBCT scans were acquired before (T1) and after completion of maxillary expansion (T2); the interval was 5.4 ± 3.4 and 6.2 ± 2.1 months between the T1 and the T2 scans of Group TBB (tooth-bone-borne) and Group BB (bone-borne), respectively. Transverse, anteroposterior and vertical linear and angular three-dimensional dentoskeletal changes were assessed after cranial base superimposition. RESULTS: Both groups displayed marked transverse skeletal expansion with a greater ratio of skeletal to dental changes. Greater changes at the nasal cavity, zygoma and orbital levels were found in Group BB. A relatively parallel sutural opening in an anterior-posterior direction was observed in Group TBB; however, the Group BB presented a somewhat triangular (V-shaped) opening of the suture that was wider anteriorly. Small downward-forward displacements were observed in both groups. Asymmetric expansion occurred in approximately 50% of the patients in both groups. CONCLUSION: Greater skeletal vs dental expansion ratio and expansion of the circummaxillary regions were found in Group BB, the group in which a bone-borne expander was used. Both groups presented skeletal and dental changes, with a similar amount of posterior palate expansion. Asymmetric expansion was observed in both groups.

Three-dimensional evaluation of skeletal and dental effects of treatment with maxillary skeletal expansion.

INTRODUCTION: The objective was to determine the skeletal and dental changes with microimplant assisted rapid palatal expansion (MARPE) appliances in growing (GR) and nongrowing (NG) patients using cone-beam computed tomography and 3-dimensional imaging analysis. METHODS: The sample consisted of 25 patients with transverse maxillary discrepancy treated with a maxillary skeletal expander, a type of MARPE appliance. Cone-beam computed tomography scans were taken before and after maxillary expansion; the interval was 6.0 ± 4.3 months. The sample was divided into GR and NG groups using cervical vertebral and midpalatal suture maturation. Linear and angular 3-dimensional dentoskeletal changes were assessed after cranial base superimposition. Groups were compared with independent-samples t test (P <0.05). RESULTS: Both groups displayed marked transverse changes with a similar ratio of skeletal to dental transverse changes and parallel sutural opening from the posterior nasal spine-anterior nasal spine; a similar amount of expansion occurred in the anterior and the posterior regions of the maxilla. The maxilla expanded skeletally without rotational displacements in both groups. The small downward-forward displacements were similar in both groups, except that the GR group had a significantly greater vertical displacement of the canines (GR, 1.7 ±1.0 mm; NG, 0.6 ± 0.8 mm; P = 0.02) and anterior nasal spine (GR, 1.1 ± 0.6 mm; NG, 0.5 ± 0.5 mm; P = 0.004). CONCLUSIONS: Treatment of patients with MARPE appliance is effective in GR and NG patients. Although greater skeletal and dental changes were observed in GR patients, a similar ratio of skeletal to dental transverse changes was observed in both groups.

Outcomes used in trials regarding the prevention and treatment of orthodontically induced white spot lesions: A scoping review.

INTRODUCTION: The objective was to identify and summarize the outcomes and evaluation methods used in clinical trials regarding the prevention and treatment of orthodontically induced white spot lesions (WSLs). METHODS: Three electronic databases were searched to identify studies that were (1) clinical trials on prevention and/or treatment of orthodontically induced WSLs, (2) reported in English, and (3) published between January 2010 and October 2019. At least 2 authors assessed the eligibility and extracted the characteristics, outcomes, and evaluation methods from included studies. All disagreements were resolved through discussion. RESULTS: Among 1328 studies identified, 51 were eligible and included. A total of 48 different outcomes and 11 different evaluation methods were used in these studies. The most frequently used outcomes were WSLs clinical visual examination scores (n = 22, 43.1%), DIAGNOdent values (n = 14; 27.5%), fluorescence loss measured with quantitative light-induced fluorescence (QLF) (n = 10; 19.6%), and lesion area measured with QLF (n = 10; 19.6%). The most frequently used evaluation methods were clinical examination (n = 25; 49.0%), visual inspection by photographs (n = 15; 29.4%), DIAGNOdent (n = 14; 27.5%), and QLF (n = 10; 19.6%). None of the included studies reported data on quality of life. CONCLUSIONS: Substantial outcome heterogeneity exists among studies regarding the prevention and treatment of orthodontically induced WSLs. Most of the identified outcomes are aimed to assess morphologic changes of WSLs and may not reflect patient perspectives. REGISTRATION: The Core Outcome Set for trials on the prevention and treatment of enamel White Spot Lesions (COS-WSL) project was registered in the COMET Initiative database (No. 1399).

Protocol for the development of a Core Outcome Set for trials on the prevention and treatment of Orthodontically induced enamel White Spot Lesions (COS-OWSL).

BACKGROUND: Enamel white spot lesions (WSLs), characterized by an opaque, matt, and chalky white appearance of enamel, are a sign of incipient caries. WSLs are common in orthodontic practice and can affect both the oral health and dental aesthetics of patients. Extensive studies have been conducted to evaluate the effectiveness of prevention or treatment for orthodontically induced enamel WSLs. However, substantial heterogeneity has been found in the outcomes used for the prevention and treatment of WSLs in literature, which prevents researchers from comparing and combining the results of different studies to draw more decisive conclusions. Therefore, we aim to develop a Core Outcome Set for trials on the prevention and treatment of Orthodontically induced enamel White Spot Lesions (COS-OWSL). METHODS: The development of COS-OWSL comprises four phases: (1) a scoping review to identify and summarize all existing outcomes that have been used in trials on the prevention or treatment of orthodontically induced WSLs; (2) qualitative interviews with orthodontic patients without (for prevention) and with WSL-affected teeth (for treatment) and relevant dental professionals to identify additional outcomes relevant to them; (3) Delphi surveys to collect opinions from key stakeholders including patients, dental professionals, and researchers and to reach a preliminary consensus; and (4) a consensus meeting to develop the final COS-OWSL. DISCUSSION: The COS-OWSL will be developed to facilitate the synthesis of evidence regarding the prevention and treatment of orthodontically induced WSLs and to promote the consistent use of relevant patient-important outcomes among future studies in this field. TRIAL REGISTRATION: Core Outcome Measures in Effectiveness Trials (COMET) initiative (the COS-WSL project) 1399.

Follow-up observation of patients with obstructive sleep apnea treated by maxillomandibular advancement.

INTRODUCTION: This study aimed to evaluate the follow-up observation of patients with obstructive sleep apnea treated with maxillomandibular advancement (MMA) procedure with or without genial tubercle advancement (GTA). METHODS: A total of 25 patients (mean age 37.1 ± 17.3 years) were included in the study. Cone-beam computed tomography scans were taken before treatment; after presurgical orthodontic treatment; immediately after MMA procedure; and follow-up visit. All Digital Imaging and Communications in Medicine files were analyzed using the Dolphin 3D Imaging software program (Dolphin Imaging and Management Solutions, Chatsworth, Calif) to determine the total airway volume (TAV), airway area (AA), and minimal cross-sectional area (MCA). Dolphin 3D voxel-based superimposition was used to determine the amount of skeletal advancement with MMA and changes after surgery. RESULTS: Significant increase in TAV, AA, and MCA was found with MMA treatment (40.6%, 28.8%, and 56.4%, respectively, P <0.0001). Smaller but significant decrease in TAV, AA, and MCA was found during a follow-up visit (20.0%, 9.7%, and 26.8%, respectively, P <0.0001) giving a net increase of TAV, AA and MCA (35.8%, 27.1%, and 45.9%, respectively). No significant differences were found in any of the airway measurements with or without the GTA procedure. The average forward movements of the maxilla, mandible, and chin were 6.6 mm, 8.2 mm, and 11.4 mm, respectively. A relapse of less than 1 mm was found in each of the variables during the follow-up period. No correlation was found between the magnitudes of skeletal advancement and the change in oropharyngeal airway space (OPAS). CONCLUSIONS: Significant increase in OPAS can be expected with MMA surgery with or without GTA procedure in patients diagnosed with obstructive sleep apnea. A partial loss in OPAS was found during the follow-up visit. The surgical movements were found to be stable, with less than 1 mm of relapse during the follow-up period, which was not clinically significant.

Stress influence on orthodontic system components under simulated treatment loadings.

BACKGROUND AND OBJECTIVE: Mini-implants have been developed and effectively used by clinicians as anchorage for orthodontic tooth movement. The objective of this study was to elucidate the stress response of orthodontic forces on the periodontal system, bone tissues, mini-implant and the bracket-enamel interface. METHODS: Computer tomography images of a commercially available mini-implant, an orthodontic bracket bonded to a central incisor, and jawbone section models were used to reconstruct three dimensional computer models. These models were exported and meshed in an ABAQUSⓇ finite-element package. Material properties, multi-segment interactions, boundary and loading conditions were then applied to each component. Finite-element analyses were conducted to elucidate the effect of orthodontic force on the equivalent von Mises stress response within the simulated orthodontic system. RESULTS: The highest stress values in the orthodontic system were predicted at the mini-implant neck, at the interface of the cortical bone, and gradually decreased in the internal apical direction of the miniscrew. On the alveolar bone, the maximum stress values were located in the alveolar cortical bone near the cervical areas of the mini-implant, which is in line with clinical findings of area where bone loss was found post orthodontic tooth treatment. Another peak of von Mises stress response was found in the enamel bracket junction with a maximum up to 186.05 MPa. To ensure good bonding between the enamel and bracket, it is vital to select carefully the type and amount of bonding materials used in the bracket-enamel interface to assure an appropriate load distribution between the teeth and alveolar bone. The results also revealed the significance of the periodontal ligaments, acting as an intermediate cushion element, in the load transfer mechanism. CONCLUSIONS: This study is sought to identify the stress response in a simulated orthodontic system to minimize the failure rate of mini-implants and bracket loss during orthodontic treatment.

Effects of Maxillary Skeletal Expansion on Upper Airway Airflow: A Computational Fluid Dynamics Analysis.

The effect of maxillary skeletal expansion (MSE) on upper airway in adolescent patients is not clear. The purpose of this study was to determine the upper airway airflow with MSE treatment using computational fluid dynamics analysis. Three-dimensional upper airway finite element models fabricated from cone beam computed tomography images were obtained before and after treatment in an adolescent patient with maxillary constriction. Turbulent analyses were applied. The nasal cavity (NC) was divided into 6 planes along the y-axis and the pharynx was divided into 7 planes in the z-axis. Changes in cross-sectional area, airflow velocity, pressure, and total resistance at maximum expiration and maximum inspiration were determined at each plane after MSE treatment. The greatest increase in area occurred in the oropharynx which was around 40.65%. The average increase in area was 7.42% in the NC and 22.04% in the pharynx. The middle part of pharynx showed the greatest increase of 212.81 mm and 217.99 mm or 36.58% and 40.66%, respectively. During both inspiration and expiration, airflow pressure decreased in both the NC and pharynx, which ranged from -11.34% to -23.68%. In the NC, the average velocity decrease was -0.18 m/s at maximum expiration (ME) and -0.13 m/s at maximum inspiration (MI). In the pharynx, the average velocity decrease was -0.07 m/s for both ME and MI. These results suggest that treatment of maxillary constriction using MSE appliance may show positive effects in improvement of upper airway cross-sectional areas and reduction of upper airway resistance and velocity.

Impact of pediatric obstructive sleep apnea on the development of Class II hyperdivergent patients receiving orthodontic treatment: A pilot study.

OBJECTIVES: To conduct a pilot study to determine if the presence of obstructive sleep apnea (OSA) influences the orthodontic treatment outcome of Class II hyperdivergent patients receiving comprehensive orthodontic treatment. MATERIALS AND METHODS: Patients between the ages of 12 and 14 who received orthodontic treatment at the Hospital of Stomatology, Wuhan University, China, were included in this study. Patients were divided into two groups: the OSA group and the control group, based on the outcome of pretreatment polysomnography findings and lateral cephalometric radiograph examination. Patients in the control group were matched with the OSA group for age, sex, ethnicity, weight, and height. Cephalometric measurements were used to record the skeletal and dental changes from before to after treatment. Data were analyzed using the t-test. RESULTS: Twenty three OSA patients and 23 control patients were included. After comprehensive orthodontic treatment, the mandibular plane angle (SN-GoMe), articular angle (SArGo), sum of Jarabak angles (SUM) and the lower gonial angle (NGoMe) were found to increase significantly in the OSA group but remained unchanged or decreased slightly in the control group ( P < .05). In the non-OSA group, the growth pattern became more horizontal. In contrast, in the OSA group the growth pattern became more vertical. Otherwise, similar treatment results were obtained for both groups in terms of sagittal change and occlusion. CONCLUSIONS: The presence of OSA in pediatric patients has a deleterious effect on the development of hyperdivergent malocclusions. Early diagnosis and management of pediatric OSA can affect the orthodontic treatment outcome of these patients.