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Background: Miniscrew-assisted rapid palatal expansion (MARPE) has emerged as a noteworthy non-surgical method for treating maxillary transverse deficiency, especially in young adult patients. Studies have shown that MARPE can achieve significant dentoalveolar and skeletal expansion with long-term stability. The primary objective of this study was to assess the skeletal changes in the maxillary transverse dimension, and the secondary objective was to evaluate the dentoalveolar changes, following the use of a commercially available maxillary skeletal expander (MSE) in comparison to a custom-fabricated MARPE., Methods: This retrospective study involved 50 young adult patients diagnosed with skeletal transverse maxillary deficiency, divided into two groups (MSE and custom MARPE), with 25 patients in each group. Pre- and post-expansion cone-beam computed tomography (CBCT) images were used to analyse skeletal, alveolar, and dental changes., Results: Both MSE and custom MARPE groups achieved significant skeletal and dentoalveolar expansion. However, the custom MARPE group exhibited notably greater expansion in several metrics; in the axial plane, the average expansion was 4.68±1.35mm and 3.37±1.53mm at the anterolateral maxillary walls and 3.99±1.35mm and 3.28±1.19mm at the greater palatine foramen region for custom MARPE and MSE groups, respectively (P<0.01). In coronal plane, the custom MARPE showed significantly greater transverse expansion at the mid-nasal, basal, alveolar, and dental levels., Conclusion: Both MARPE systems are effective for maxillary expansion. However, the custom-fabricated MARPE may offer more favourable results, with broader and more uniform skeletal expansion. This can be especially beneficial for patients with specific anatomical requirements., (Copyright © 2024 CEO. Published by Elsevier Masson SAS. All rights reserved.)

Objective: To investigate the morphological and positional temporomandibular joint (TMJ) characteristics of different temporomandibular disorders (TMDs)., Methods: One hundred forty-three TMD patients were divided into three groups: Group 1: Myalgia (M), Group 2: Disc displacement with reduction (DDWR), and Group 3: Disc displacement without reduction (DDWOR). Three-dimensional positional and dimensional parameters of the TMJ, including mandibular fossa, condyle, and TMJ spaces were evaluated using cone beam computed tomography (CBCT). The significance level was p < 0.05., Results: Mandibular condyles were significantly positioned in more vertical, posterior, and medial directions, with the reduced condylar width in the DD groups ( p < 0.001). Anterior joint space was significantly higher in the DDWR group than the myalgia group; the superior joint spaces were more reduced in DD groups than the myalgia group., Conclusion: Patients diagnosed with disc displacement showed significantly different condylar positions and joint spaces compared to the myalgia group in a skeletally comparable sample.

Objective: To three-dimensionally evaluate the position and morphology of the TMJ in skeletal Class I with variable degrees of overbite and overjet in comparison with normal peers., Methods: Pretreatment CBCT scans of 126 adults were retrieved. Based on the severity of overjet and overbite, the sample was divided into three main groups and six subgroups (18 patients each): the first group with a normal overbite and variable overjet degree and the second group with normal overjet and variable overbite degree. These six subgroups were compared with a third control group of normal overjet and overbite., Results: There were significant differences in vertical condylar position, vertical and anteroposterior condylar inclinations, condylar height, and significant posterior condylar positioning in severe deep overbite, compared with the control group., Conclusion: There were significant changes in the TMJ components in severe deep overbite cases. Therefore, sever deep overbite could be considered a predisposing factor for temporomandibular disorders.

Objective: This systematic review aimed to appraise the reliability and comprehensiveness of imaging methods in studies that used three-dimensional assessment of the temporomandibular joint (TMJ) in order to propose a standardized imaging method., Methods: Six databases/search engines were searched up until September 2022. The outcomes of interest included measurements of the mandibular condyle, glenoid fossa, joint spaces, or the entire TMJ. Two checklists were utilized: one to assess the risk of bias, with a maximum score of 37, and the other, a pre-designed checklist consisting of 22 items to evaluate the comprehensiveness of the methods used, with a maximum score of 33., Results: Out of the 2567 records retrieved, only 14 studies, which used cone bean computed tomography (CBCT), were deemed eligible and thus included in the qualitative analysis. Three studies were deemed of low risk of bias, while the remaining studies were rated as moderate to high risk of bias, primarily due to improper reporting of inter-observer agreement, varying reliability values, and a limited number of cases included in the reliability analysis. Regarding the comprehensiveness of the methods used, only four studies achieved relatively high scores. The deficiencies observed were related to the reporting of variables such as slice thickness and voxel size, absence of or improper reporting of intra- and inter-examiner reliability analyses, and failure to assess all osseous components of the TMJ., Conclusion: CBCT-based methods used to assess the positions and morphology of TMJ bony structures appear to be imperfect and lacking in comprehensiveness. Hence, criteria for a standardized assessment method of these TMJ structures are proposed., Clinical Relevance Statement: Accurately, comprehensively, and reliably assessing the osseous structures of the temporomandibular joint will provide valid and valuable diagnostic features of the normal temporomandibular joint, and help establish potential associations between these osseous features and temporomandibular disorders., Registration: The protocol for this systematic review was registered at the International Prospective Register of Systematic Reviews (PROSPERO, No.: CRD42020199792)., Key Points: •Although many methods have been introduced to assess the osseous structure of the temporomandibular joint, they yielded inconsistent findings. •None of the published studies comprehensively assessed the temporomandibular joint. •Recommendations for a comprehensive temporomandibular joint osseous assessment method were suggested for better validity and reliability of future research., (© 2023. The Author(s).)

Objective: This study sought to three-dimensionally (3D) evaluate the maxillomandibular basal bone and dentoalveolar widths using cone-beam computed tomography (CBCT) scans in adult Chinese populations with different vertical and sagittal facial skeletal patterns whilst no apparent posterior dental crossbite., Materials and Methods: The retrospective cross-sectional comparative study enrolled CBCT images of 259 adult patients (125 males and 134 females). The subjects were divided into the hyperdivergent(n = 82), hypodivergent(n = 88), and normodivergent(n = 89) groups based on the Jarabak ratio (S-GO/N-Me), which were further divided into three subgroups of skeletal Class I, II and III, based on both the ANB angle and AF-BF parameters. ANOVA was used to analyze the extracted data of the studied groups. The intra- and inter-observer reliability was analyzed using the intra-class correlation coefficient (ICC)., Results: In all three vertical facial skeletal patterns, the skeletal Class II had significantly smaller mandibular basal bone width compared to skeletal Class I and Class III, both at the first molar and first premolar levels. The skeletal Class III seemed to have smaller maxillary basal bone width compared to skeletal Class I and Class II malocclusions; however, a significant difference was found only in the normodivergent pattern. As for the dentoalveolar compensation, it was most notable that in the hypodivergent growth pattern, the skeletal Class II had significantly smaller maxillary dentoalveolar width compared to the Class I and Class III groups, both at the first molar and first premolar levels., Conclusions: Based on the sample in the present study, skeletal Class II has the narrowest mandibular basal bone regardless of the vertical facial skeletal pattern., Clinical Relevance: For Chinese adults with no apparent transverse discrepancy, the maxillomandibular basal bone and dentoalveolar widths are revealed in specific categories based on different vertical and sagittal facial skeletal patterns. In diagnosis and treatment planning, particular attention should be paid to skeletal Class II for possibly existing mandibular narrowing., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Temporomandibular disorder (TMD) is a grouping of heterogeneous disorders with multifactorial origins. Stabilization splints (SS) have demonstrated an acceptable treatment effect in TMD. The possible changes at the skeletal, dental, and soft tissue levels need to be addressed to evaluate the benefit/risk ratio of this therapeutic procedure. Accordingly, this study aimed to three‑dimensionally evaluate skeletal, dentoalveolar and soft tissue changes after SS treatment for patients with TMD., Methods: This retrospective study included 74 adult patients with myofascial and/or intra-articular disorders (25 males and 49 females), with an average age of 22.88 ± 4.8 years, who underwent SS treatment. Pre- and post-treatment Cone beam computed tomography were analysed using Invivo 6.0.3 software. The primary outcome was the vertical skeletal and dentoalveolar changes, while the secondary outcomes were the anteroposterior skeletal, dentoalveolar and soft tissue changes. Paired t-test and Wilcoxon rank sum test were used for statistical analyses., Results: For the primary outcome; skeletally, there was a significant increase in mandibular plane inclination (difference: 0.82°±1.37), decrease facial height ratio (difference: 0.45%±1.07) and at the dentoalveolar level, the inclination of the functional (FOP-SN, FOP-FH) and bisecting (BOP-SN, BOP-FH) occlusal planes exhibited a significant increase too (difference: 0.38 ± 1.43°, 0.49 ± 1.62°, 0.44 ± 1.29° and 0.41 ± 1.17°, respectively) and also a decrease in the overbite (difference: -0.54 ± 0.83). For the secondary outcomes; there was a significant decrease in mandibular position (SNB) (difference: 1.60 ± 1.36°) and increase in the overjet (difference: 0.93 ± 1.04, p < 0.001) and a significant lower lip retrusion (difference: 0.33 ± 1.01 mm p < 0.01), was observed too., Conclusions: SS therapy resulted in significant vertical skeletal and dentoalveolar changes that were manifested mainly by facial height ratio, mandibular and occlusal plane changes, and to a lesser extent, significant anteroposterior skeletal, dentoalveolar, and soft tissue changes in the form of mandibular position, increased overjet and a more retrusive lower lip. These changes should be considered during patients' selection prior to initiating SS therapy., (© 2024. The Author(s).)

Background: The aim of this study was to evaluate an objective method for Cervical Vertebral Maturation (CVM) staging., Methods: An initial sample of 647 Lateral Cephalometric Radiographs (LCR) were staged according to the CVM (Baccetti et al.) by 4 examiners. The final sample (n = 394) included LCR on which the staging of the 4 investigators matched. The objective staging was performed by a single operator. The sample was divided according to the maturational stages into pre-pubertal, pubertal and post-pubertal groups. Measurements were performed on the cervical vertebrae (C2, C3 and C4). The angle between posterior and superior borders for C3 and C4 was the Superior Wall Inclination Angle (SWIA). Concavity Depth (CD) for C2, C3 and C4, and Body Shape (BS) (ratio of width to height of C3 and C4). Measurements of the 3 groups were compared., Results: Reliability of subjective staging was high (intra-observer reliability, 0.948; inter-observer reliability, 0.967). Good agreement was observed for the outcomes measured. Intra-observer reliability was good (0.918, 0.885 and 0.722 for CD, BS and SWIA, respectively). The same was for the inter-observer reliability results (0.902, 0.889 and 0.728 for CD, BS and SWIA, respectively). Significant differences were observed for mean values of SWIA and BS and median values of CD within maturational stage. Similar findings were observed when the outcomes were compared at different phases (P < 0.001)., Conclusions: A standardized, objective staging system using linear, angular measurements and ratios was applied for the determination of cervical vertebral maturation., (© 2024. The Author(s).)

Objective: The goal of this systematic review and meta-analysis was to assess whether the dimensions of the frontal air sinus correlate with skeletal malocclusion., Study Selection: PubMed, Scopus, Embase, and Google Scholar were searched for relevant studies published up to May 23, 2023. The review included observational and retrospective studies that compared the dimensions of the frontal air sinus between different skeletal malocclusions. The PECOS method was used in this study ("Population, Exposure, Comparator, Outcome, and Study design"). The search was done using the following English keywords: "frontal sinus" OR "lateral cephalometric" OR "malocclusion" AND "surface area"., Results: Seven studies were included, which involved 1101 participants, of whom 403 were class I, 375 were class II, and 323 were class III. These studies had a moderate risk of bias. The surface area of the frontal sinus in class III was significantly larger than in class I (standardized difference in means (SDM) = -0.971; 95 % CI = -1.147- -0.796; P < 0.001) and in class II (SDM = -1.535; 95 % CI = -1.732- -1.337; P < 0.001)., Conclusion: Class III malocclusion is associated with a larger surface area of the frontal sinus compared to classes I and II., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Zhihua Li reports financial support was provided by Health Commision of Jiangxi province. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Objective: This study aimed primarily to analyze the three-dimensional (3D) changes in the pharyngeal airway (PA), and secondarily, the hyoid bone (HB) and the craniocervical (CC) following stabilization splint (SS) therapy in adult patients with temporomandibular joint disorders (TMD) and mandibular deviation (MD)., Methods: Thirty-five adult patients with TMD and MD, who were treated using SS with a mean age of 25.14 ± 6.11 years, were enrolled in this retrospective clinical study. Pre- and post-therapeutic cone-beam computed tomography (CBCT) scans were analyzed. PA dimension,nasopharyngeal, oropharyngeal, hypopharyngeal, sub-hypopharyngeal, and total pharyngeal airway spaces were measured in surface area, volume, minimum constricted area (MCA) and width, HB position, and CC posture were analyzed three-dimensionally using InVivo 6.0.3 and Dolphin 11.95 software. Wilcoxon rank-sum or Paired t-test was conducted, and P < 0.05 was considered significant., Results: SS therapy was administered for a period of 9.49 ± 4.02 months. The oropharyngeal airway space showed a significant decrease in sagittal width. The hypopharyngeal surface area, volume, MCA, and sagittal width decreased significantly. In terms of HB, hyoid-mandibular plane (H-MP), retrognathia-third vertebra's most inferior-anterior (RGN-C3ia), and retrognathia-Sella (RGN-S) distances significantly decreased. The Nasion-Sella line and the line that passes through C2ip to the odontoid process posterior tangent (NSL-OPT) angle in CC posture also decreased significantly., Conclusion: SS therapy in TMD patients with MD mainly results in narrowing of the hypopharyngeal region, no change in HB position and improvement in head posture. These results undoubtedly assist in diagnosis and treatment of clinical conditions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Objective: This study evaluated the dimensional and positional osseous temporomandibular joint features in normodivergent facial patterns with and without temporomandibular disorders., Methods: A total of 165 adult patients were divided into two groups: group 1 (n = 79 patients; 158 joints): temporomandibular disorders patients and group 2 (n = 86 patients; 172 joints): non-temporomandibular disorders patients. Three-dimensional positional and dimensional temporomandibular joint characteristics, including glenoid fossa, mandibular condyles, and joint spaces, were assessed by cone beam computed tomography., Results: The glenoid fossa positions in the three orthogonal planes and height showed statistical significance between the two studied groups. The temporomandibular disorders patients showed higher horizontal and vertical condyle inclinations while anteroposterior inclination was less, and the condyle was positioned more superior, anterior, and lateral in the glenoid fossa. The condyle width and length showed no significance between the two groups, while condyle height was smaller in temporomandibular disorders patients. Anterior and medial joint spaces increased while the superior and posterior joint spaces reduced in temporomandibular disorders patients., Conclusion: There were significant differences between the patients with and without temporomandibular joint disorders in terms of mandibular fossa positions and height as well as condylar positions and inclinations in horizontal and vertical planes together with reduced condylar height and reduced posterior and superior joint spaces in the temporomandibular disorders patients., Clinical Relevance: The temporomandibular disorder is a multifactorial disorder in which one of these factors is the dimensional and positional characteristics of the temporomandibular joints; including or excluding this factor requires a comprehensive three-dimensional investigation of patients with TMD compared to the normal group under the condition that the facial pattern is average as a confounding factor., (© 2023. The Author(s).)

Background: Skeletal class III malocclusion has a diverse and complicated aetiology involving environmental and genetic factors. It is critical to correctly classify and define this malocclusion to be diagnosed and treated on a clinically sound basis. Thus, this study aimed to provide reliable and detailed measurements in a large ethnically homogeneous sample of Chinese adults to generate an adequate phenotypic clustering model to identify and describe the skeletal variation present in skeletal class III malocclusion., Materials and Methods: This is a retrospective cross-sectional study in which 500 pre-treatments cone-beam computed tomography (CBCT) scans of patients with skeletal class III malocclusion (250 males and 250 females) were selected following specific selection criteria. Seventy-six linear, angular, and ratios measurements were three-dimensionally analysed using InVivo 6.0.3 software. These measurements were categorised into 47 skeletal, 18 dentoalveolar, and 11 soft tissue variables. Multivariate reduction methods: principal component analyses and cluster analyses were used to present the most common phenotypic groupings of skeletal class III malocclusion in Han ethnic group of Chinese adults., Results: The principal component analysis revealed eight principal components accounted for 72.9% of the overall variation of the data produced from the seventy-six variables. The first four principal components accounted for 53.37% of the total variations. They explained the most variation in data and consisted mainly of anteroposterior and vertical skeletal relationships. The cluster analysis identified four phenotypes of skeletal class III malocclusion: C1, 34%; C2, 11.4%; C3, 26.4%; and C4, 28.2%., Conclusion: Based on three-dimensional analyses, four skeletal class III malocclusion distinct phenotypic variations were defined in a large sample of the adult Chinese population, showing the occurrence of phenotypic variation between identified clusters in the same ethnic group. These findings might serve as a foundation for accurate diagnosis and treatment planning of each cluster and future genetic studies to determine the causative gene(s) of each cluster., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: The purpose of this study was to three-dimensionally evaluate the relationship between the degree of bilateral impacted mandibular third molar (IM3M) angulation and the mandibular dental arch parameters in normal skeletal and dental malocclusion patients., Materials and Methods: In this retrospective cross-sectional comparative study, 120 adult subjects' cone-beam computed tomography (CBCT) images were three-dimensionally analyzed. The sample included 120 adults aged 20-30 years, with a gender distribution of 51 male and 69 female participants. The sample was divided into 100 adults with bilateral IM3M (study group) and 20 adults with normal bilateral erupted M3M (control group). The study group was sub-divided into three groups according to the degree of IM3M buccolingual angulation (BL°): group A, < 12° on the center of the ridge (N = 30), group B, 12-24° off-center of the ridge (N = 40), group C, > 24° off-center of the ridge (N = 30). The study group was also sub-divided into two groups according to IM3M mesiodistal angulation (MD°): group 1 from 10 to 45° (N = 36), group 2 > 45° (N = 64). Comparison within and between groups was performed using one-way ANOVA followed by Tukey's post hoc test. The correlation between IM3M, BL, and MD angulation and the mandibular arch parameter was calculated using Pearson's correlation coefficient., Results: Statistically significant differences (P < 0.001) were found between the IM3M BL° and anterior teeth inclination, arch length (AL), and inter-second molar width (inter 2 nd MW) as well as between the IM3M MD° with anterior crowding and the arch length (P < 0.001). A significant positive correlation was found between IM3M BL° and anterior teeth inclination and between IM3M MD° and anterior teeth crowding and inter 2 nd MW. A significant negative correlation was observed between IM3M BL° and inter 1 st MW and 2 nd MW., Conclusion: The degree of buccolingual and mesiodistal angulation of the impacted mandibular third molars was related with mandibular dentoalveolar changes. Increased buccolingual angulation is generally associated with increased anterior teeth inclination and decreased 1 st and 2 nd inter-molar width. The increase in mesiodistal angulations was generally related with increased anterior teeth crowding and 2 nd inter-molar width., Clinical Relevance: Assessment of the relationship between the impacted mandibular third molars and the degree of arch discrepancy, and the position of mandibular incisors in the three planes of space might help in the decision-making process for the extraction of the impacted third molars in adult patients., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: The present study aimed to estimate the location of the incisive canal (IC) concerning the upper central incisor roots (U1) in order to explore the amount of incisor retraction as per the envelope of discrepancy amongst Chinese patients with different vertical facial growth patterns., Methods: This is a cross-sectional study that used a total of 207 pretreatment cone-beam computed tomography (CBCT) scans of adults with a skeletal class I relationship. Sixty-nine cases were included in each of the normodivergent, hypodivergent, and hyperdivergent facial groups. The IC volume was measured using Mimics 21 software. The IC width and IC-U1 proximity were measured using in vivo 6 software. Linear measurements were conducted at 3 vertical levels., Results: The IC has shown a larger volume in the hyperdivergent group and male patients. Overall, the IC has recorded linear width greater than the inter-root distance of U1 in 59.1%, 66%, and 68.8% amongst the normodivergent, hypodivergent, and hyperdivergent facial groups, respectively, and in 58.3% of males and 70.8% of females. The overall sagittal distances between the U1 and IC were 4.00 ± 0.82 mm, 4.60 ± 0.83 mm, and 3.60 ± 0.80 mm amongst the normodivergent, hypodivergent, and hyperdivergent facial groups, respectively., Conclusions: The maximum sagittal distances between U1 and IC were 4.8 mm, 5.4 mm, and 4.4 mm amongst the normodivergent, hypodivergent, and hyperdivergent facial groups, respectively. Thereby, our findings have revised the retraction aspect of the envelope of discrepancy as per the different vertical facial growth patterns, which could serve a reference for the clinical practice involved considerable incisors movement, especially among Chinese patients., Competing Interests: Conflict of interest None disclosed., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: This study aimed to assess the alveolar bone changes following maxillary and mandibular molars' intrusion and extrusion movements using Clear Aligners using Cone-Beam Computed Tomography (CBCT)., Materials and Methods: This is a retrospective clinical study in which 24 adult patients with pre-designed selection criteria and a mean age of 31.1 + 9.9 years were enrolled. The alveolar bone changes around one hundred thirty-three maxillary and mandibular molars intruded or extruded by Clear Aligners therapy were analyzed from CBCT using Invivo 6.0 software. Intra- and inter-examiner reliability analysis was performed using the intra-class correlation coefficient (ICC) and Cronbach's Alpha statistics. The paired t-test was used to analyze significant differences before and after treatment (T0-T1). The significance level was considered at P < 0.05., Result: The patients were divided into two groups: extrusion (48.9%, n = 65 molars' root) and intrusion (51.1%, n = 68 molars' root) group. There was a significant decrease in the alveolar bone changes in the buccal surface of the mandibular right and left 1st molars in the extrusion group (-1.05 ± 0.97, -0.76 ± 1.12 mm, respectively) and the maxillary left 2nd molars in intrusion group (-0.42 ± 0.77 mm), and the lingual surface of intrusion of the mandibular left 1st molar (-0.64 ± 0.76 mm). Comparing the mean maxillary and mandibular changes (T0-T1) of both studied groups showed that the buccal alveolar bone changes for the left 1st and right 2nd molars showed a significant difference in extrusion and intrusion groups, respectively., Conclusions: The buccal alveolar bone changes is considered the most affected surface following maxillary and mandibular molars' intrusion and extrusion movements using clear aligners, with mandibular molars being more affected than the maxillary ones., (© 2023. The Author(s).)

Objective: This study aimed to explore the quantitative and qualitative condylar changes following stabilization splint (S.S) therapy, including condylar position, morphology, and bone mineral density (BMD) in subjects with temporomandibular disorders (TMD)., Materials and Methods: In this retrospective clinical study, we enrolled 40 TMD subjects (80 joints) aged 18 to 35 years, for whom a S.S was used to treat TMD. The 80 TMD consists of 32 masticatory muscle disorders (myalgia) and 48 TMJ disorders (arthralgia). Cone beam computed tomography (CBCT) was used to scan the TMJs of subjects pre- and post-treatment for three-dimensional analysis (3D). Using Mimics software v.21.0, quantitative (3D condylar and joint spaces dimensions parameters were measured using linear measurements in millimeters, according to the Kamelchuk method and Ikeda method, while the assessment of anteroposterior condyle position within the glenoid fossa was based on the method of Pullinger and Hollender), and qualitative (a round bone tissue with an area of 2 mm 2 in three representative areas according to the Kamelchuk method to measure condylar BMD) pre- and post-treatment. Intra- and inter-group statistical comparisons were performed using the Wilcoxon signed ranks and the Kruskal-Wallis test, respectively., Results: The course of treatment was 6-12 months, with an average of 9.1 months. For the pre- and post-treatment quantitative comparisons, there was a statistically significant difference in the anterior joint space (AJS) and coronal medial space, as well as the condyle length in the myalgia group and condylar width in the arthralgia group. For qualitative measurements, a significant difference was observed in the posterior slope of the myalgia group and the arthralgia group's anterior, superior, and posterior slopes. The inter-group comparisons revealed significant differences in AJS, condylar length, and anterior slope density., Conclusion: In short-term follow-up, the S.S influenced patients with TMD from different origins; it changes anterior and coronal medial joint space, condyle length in myalgia, and width in arthralgia. Furthermore, it improved the condyle bone density more evidently in arthralgia., Clinical Relevance: This study highlights the influence of S.S on symptomatic populations with TMD of different origins from a qualitative and quantitative perspective., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: This study aimed to investigate the effect of vertical facial patterns on the developmental relationship between the nasal bone and maxillary central incisors., Methods: In this retrospective comparative study, the lateral cephalograms of 213 subjects (51 Males, 162 Females) with skeletal Class I malocclusion (aged 18-32 years) were classified into three equal groups: (1) hyperdivergent, (2) normodivergent, and (3) hypodivergent facial patterns based on the mandibular plane inclination (S-N/Go-Me). Several sets of measurements were extracted: (1) gradient and length of the nasal bone and maxillary central incisor, (2) the distance from apex and root of the nasal bone, and (3) maxillary central incisor to the true perpendicular from the digitized lateral cephalograms. The significance level was considered at P < 0.05., Results: The inclination angle and length between nasal bone and maxillary central incisor were positively correlated independent of vertical facial type. The inclination angle of the nasal bone in the hypodivergent group was significantly larger than the other two vertical facial patterns. The inclination angle of the maxillary central incisor increased successively in the hyperdivergent, normodivergent, and hypodivergent groups. The length of the nasal bone in the hyperdivergent group was significantly longer than that in the hypodivergent and normodivergent groups. The maxillary central incisor length in the hyperdivergent group was significantly longer than in the hypodivergent group., Conclusion: A correlation between nasal bone and maxillary central incisors during the growth and development of the maxillofacial region was found. In Class I malocclusion subjects, hypodivergent patients were more likely to have a prominent and relatively short nasal bone and maxillary central incisors and vice versa., (© 2023. The Author(s).)

Objective: This study aimed to assess the dimensional and morphological measurements of the frontal air sinuses in different ages and genders in the two ethnicities., Materials and Methods: This retrospective study included 360 subjects (160 males and 200 females) of both ethnicities. Subjects were divided based on age and gender into four groups, including an equal number of both males and females, for each age and ethnic group. The frontal air sinus dimensions were measured utilizing lateral cephalometric radiographs and computed using Winceph version 9.0 software. The frontal air sinus dimensions were compared between age groups in both genders and between ethnicity using an independent sample t test. The relationship between the frontal air sinus dimensions and subjects' age was evaluated using Pearson's correlation coefficient., Result: The frontal air sinuses measurements were larger in males than females in both ethnicities, except for the frontal sinus index, which was found to be larger in females than males. The frontal air sinus surface area and height showed statistically significant differences between the two age groups in both ethnicities (P < 0.05). The Arabian-Caucasian patients had a larger frontal sinus surface area, height, and depth than the Han-Chinese patients in both age groups., Conclusion: The size of the frontal air sinus increases with age; and continues to expand after the age of 20 years. Based on the Arabian-Caucasian and Han-Chinese sub-population findings, the frontal sinus is an effective tool for determining gender and appears to have potential in ethnicity identification., (© 2022. The Author(s) under exclusive licence to Japanese Society for Oral and Maxillofacial Radiology.)

Background: This study aimed to three-dimensionally compare the maxillary growth among the spheno-occipital synchondrosis (SOS) maturation stages in both genders., Methods: This is a cross-sectional study of a retrospective type in which cone-beam computed tomography (CBCT) images of 500 patients aged 6 to 25 years (226 males and 274 females) were analyzed. The SOS was evaluated using the four-stage scoring system; completely open, partially fused, semi-fused, or completely fused. The SOS scoring and three-dimensional cephalometric measurements were analyzed by Invivo 6.0.3 software. Descriptive and analytical statistics were performed and a P-value < 0.05 was considered statistically significant., Results: There was a statistically significant difference in maxillary measurements among SOS maturation stages in both genders (P < 0.05). The mean differences in the maxillary growth among the SOS maturation stages between SOS stages 2 and 3 were higher than those between stages 1and 2 and stages 3 and 4 for maxillary length and height in both genders. However, the mean difference in the maxillary width was higher between SOS stages 1 and 2 than those stages 2 and 3 and stages 3 and 4. On other hand, there may be lesser maxillary growth between SOS stages 3 and 4 for maxillary width, length (in males), and height. The growth curves showed high active growth of the maxilla as the SOS was still fusing (especially stage 2 and 3) than those of the fused (stage 4). Moreover, the acceleration of growth occurred earlier in females than males regarding chronological age but not for SOS maturation stages., Conclusions: The SOS maturation stages are valid and reliable maxillary skeletal maturation indicators for three-dimensional maxillary growth in both genders., (© 2023. The Author(s).)

Objectives: This study aimed to determine the three-dimensional (3D) correlation between maxillomandibular complex parameters and pharyngeal airway dimensions in different sagittal and vertical malocclusions., Methods: This retrospective cross-sectional study included the CBCT scans of 368 patients with a mean age of 23.81 ± 3.01 years. The patients were classified into three groups (skeletal Class I, II, and III). Each class group was divided into three subgroups based on vertical growth patterns (hypo-, normo-, and hyperdivergent). The maxillomandibular complex was evaluated in the three planes using 16 skeletal measurements. Naso-, oro-, hypo-, and total pharyngeal airway spaces were assessed in terms of width, volume, surface area, and minimum constricted area (MCA). Two-way ANOVA followed by the Bonferroni post-hoc test were used., Results: The nasopharyngeal airway space was significantly lowest regarding sagittal and lateral widths in the skeletal Class III patients, the lowest volume and surface area were in hyperdivergent patients, and MCA was the highest in Class II and hypodivergent patients. The oro- and hypopharyngeal sagittal width, volume, surface area, and MCA were the lowest in the hyperdivergent patients, and oropharyngeal lateral width and hypopharyngeal sagittal width were the highest in skeletal Class III. The total pharyngeal volume, surface area, and MCA were the lowest in the hyperdivergent patients, and skeletal Class II patients had the lowest MCA., Conclusions: The pharyngeal airway dimensions differ with various sagittal and vertical malocclusions. These differences could apply to diagnosis, treatment planning, and possible changes following orthodontic/orthopedic or surgical treatment.

Background: Three-dimensional (3D) detailed evaluations of the mandibular mediolateral position, mandibular condylar position, and temporomandibular joint (TMJ) spaces following stabilization splints (SS) therapy in patients with temporomandibular joint disorders (TMD) and mandibular deviation (MD) have not been reported in the available literature. Accordingly, this study aimed to three-dimensionally analyze the skeletal and bony temporomandibular joint changes following stabilization splint therapy in adult patients with temporomandibular joint disorders and mandibular deviation., Methods: This study is a retrospective clinical study that enrolled 26 adult patients with TMD and MD with a mean age of 24.86 years. The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) was used to diagnose TMD. SS was adjusted weekly until occlusal contact stabilization occurred, and then adjusted monthly, patients were instructed to wear it at night for at least 10 h. The SS was removed after the elimination of TMD symptoms (TMJ/muscle pain on palpation, muscle spasm, and clicking) and having both condyles completely seated in a musculoskeletally stable position. Pre- and post-therapeutic Cone Beam Computed Tomography (CBCT) was analyzed. Mandibular mediolateral position, TMJ spaces, and mandibular condyle position were analyzed three-dimensionally using Mimics 21.0 software. Paired t-test or Wilcoxon rank-sum test was performed, and the significance level was considered at P < 0.05., Results: The treatment period with SS therapy was 10.07 ± 3.1 months. The deviated chin was improved in 69.23% of the sample; the range of improvement was > 0 mm ≤ 3.9 mm. The mandibular rotation was significantly decreased from 3.58 ± 2.02° to 3.17 ± 1.60. The deviated side's superior and posterior joint TMJ spaces were significantly increased from 2.49 ± 0.88 mm and 1.25 ± 0.79 mm to 2.98 ± 1.02 mm and 1.86 ± 0.72 mm, respectively. The value of the difference from the bilateral condyle head position to the X and Z axes significantly decreased from 2.50 ± 1.56 mm and 2.30 ± 1.57 mm to 1.64 ± 1.58 mm and 1.82 ± 1.11 mm, respectively., Conclusion: The main positional effect of the stabilization splint treatment in TMD patients with MD includes considerable correction of mandibular deviation, improving facial asymmetry, and moving the condyle into a stable condylar position; these were done by promoting the mandible to rotate around the Z (roll) and Y (yaw) axes and by forward, downward, and outward condylar movement on the deviated side, respectively., (© 2023. The Author(s).)

Background: This study aimed to compare spheno-occipital synchondrosis (SOS) maturation stages with a three-dimensional assessment of mandibular growth., Methods: This is a cross-sectional study of a retrospective type, in which cone-beam computed tomography (CBCT) images of 500 patients aged 6 to 25 years (226 males and 274 females) were analyzed. The SOS was evaluated using the four-stage scoring system; completely open, partially fused, semi-fused, or completely fused. The SOS scoring and three-dimensional cephalometric measurements were analyzed by Invivo 6.0.3 software. Descriptive and analytical statistics were performed, and a P-value < 0.05 was considered statistically significant., Results: There was a statistically significant difference in mandibular measurements among SOS maturation stages in both sexes (P < 0.05). The skeletal growth increments of mandibular variables across the SOS stages had higher mean differences between SOS stages 2 and 3 than those between stages 1 and 2 and stages 3 and 4 in both sexes. The mandibular growth curves increased with chronological age (earlier in females) and SOS maturation stages (mostly in stages 1, 2, and 3 than stage 4)., Conclusions: The SOS maturation stages are valid and reliable mandibular skeletal indicators as evaluated with three-dimensional cephalometric mandibular measurements. The findings of growth increments and constructed growth curves of mandibular growth might be helpful in diagnosis and treatment planning., (© 2022. The Author(s).)

Aim: This study sought to evaluate dimensional and positional temporomandibular joint (TMJ) features in three-dimensions in skeletal class II malocclusion with and without temporomandibular disorders (TMDs)., Materials and Methods: A total of 91 (182 joints) adult patients were divided into the following two groups: (1) Group I - TMD ( n = 56; 112 joints) and (2) group II - non-TMD ( n = 35; 70 joints). Dimensional and positional TMJ characteristics including glenoid fossae, mandibular condyles, and joint spaces were assessed using cone-beam computed tomography (CBCT)., Results: The mandibular fossa in the TMD group was significantly more lateral than in the non-TMD group, and the mandibular fossa anterior wall inclination to the horizontal plane showed a significantly more vertically inclined wall in the TMD group compared to the non-TMD group. Significantly vertical mandibular condylar changes in the form of less vertical inclination, more vertical position, and lower vertical dimension (height) in addition to more upward position within the joint space were found. The TMD group showed significantly decreased superior and posterior joint spaces in addition to significantly increased medial joint spaces., Conclusion: Patients with TMDs are associated with laterally positioned mandibular fossa with the more vertically inclined anterior wall. They are characterized by vertical mandibular condylar changes in the form of less vertical inclination, more vertical position, and lower vertical dimension (height) in addition to more upward positioning within the joint space is accompanied by a decrease in superior and posterior and an increase in medial joint spaces., Clinical Significance: The TMJ characteristics of skeletal class II make it more susceptible to TMDs and any orthodontic and/or surgical interventions in a direction possibly change these characteristics are to be considered.

Objectives: To investigate canine retraction (CR) and anchorage loss (AL) among average facial height (AFH) and high facial height subjects (HFH) with or without piezocision surgery (PS)., Materials and Methods: This was a split-mouth, randomized clinical trial. Twenty-three females (aged 19.05 ± 2.95 years) who presented with Class II division I malocclusion requiring bilateral maxillary extraction and who fulfilled eligibility criteria were included and categorized into two groups: AFH (12 participants) and HFH (11 participants). Atraumatic extractions were performed 10 weeks following bonding. Before space closure, impressions were taken to fabricate models, which were scanned to generate digital models. Each participant had PS on the randomly assigned side. Space closure was undertaken using 100-g nickel-titanium coil closing springs on 0.019 × 0.025-inch stainless steel archwire. Digital models were collected 6 and 12 weeks post-PS. They were superimposed using reliable reference points and a region of interest on the palate, and crown movements were analyzed in three dimensions., Results: Three months post-PS, intergroup comparisons showed that rates of CR for control sides (mean = 1.88 ± 0.83 mm for AFH, mean = 1.76 ± 0.62 mm for HFH) and intervention sides (mean = 1.48 ± 0.74 mm for AFH, mean = 1.40 ± 0.85 mm for HFH) were not significantly different. AL was not significantly different (P &gt; .05) between groups., Conclusion: Regardless of whether the patient underwent PS, CR and AL rates for AFH and HFH patients were not significantly different., (© 2022 by The EH Angle Education and Research Foundation, Inc.)

Objective: This systematic review evaluated the available evidence regarding the skeletal, dentoalveolar, and soft tissue effects of orthodontic camouflage (OC) versus orthodontic-orthognathic surgical (OOS) treatment in borderline class III malocclusion patients., Methods: Eligibility criteria. The included studies were clinical trials and/or follow-up observational studies (retrospective and prospective). Information sources. PubMed, Scopus, Science Direct, Web of Science, Cochrane, and LILACS were searched up to October 2021. Risk of bias. Downs and Black quality assessment checklist was used. Synthesis of results. The outcomes were the skeletal, dentoalveolar, and soft tissue changes obtained from pre- and post-cephalometric measurements., Results: Included studies. Out of 2089 retrieved articles, 6 were eligible and thus included in the subsequent analyses. Their overall risk of bias was moderate. Outcome results. The results are presented as pre- and post-treatment values or mean changes in both groups. Two studies reported significant retrusion of the maxillary and mandibular bases in OC, in contrast to significant maxillary protrusion and mandibular retrusion with increased ANB angle in OOS. Regarding the vertical jaw relation, one study reported a significant decrease in mandibular plane inclination in OC and a significant increase in OOS. Most of the included studies reported a significant proclination in the maxillary incisors in both groups. Three studies reported a significant proclination of the mandibular incisors in OOS, while four studies reported retroclination in OC., Conclusion: Interpretation. The OSS has a protrusive effect on the maxillary base, retrusive effect on the mandibular base, and thus improvement in the sagittal relationship accompanied with a clockwise rotational effect on the mandibular plane. The OC has more proclination effect on the maxillary incisors and retroclination effect on the mandibular incisors compared to OOS. Limitation. Meta-analysis was not possible due to considerable variations among the included studies. Owing to the fact that some important data in the included studies were missing, conducting further studies with more standardized methodologies is highly urgent. Registration. The protocol for this systematic review was registered at the International Prospective Register of Systematic Reviews (PROSPERO, No.: CRD42020199591)., Clinical Relevance: The common features including skeletal, dental, and soft tissue characteristics of borderline class III malocclusion cases make it more difficult to select the most appropriate treatment modality that can be either OC or OOS. The availability of high-level evidence-systematic reviews-makes the clinical decision much more clear and based on scientific basis rather than personal preference., (© 2022. The Author(s).)

Background: This study aimed to three-dimensionally evaluate the qualitative and quantitative maxillary basal, dentoalveolar, and dental dimensions in patients with unilateral or bilateral maxillary impacted canines relative to their normal peers., Materials and Methods: This is a retrospective comparative study. Cone-beam computed tomography images of one hundred and fifty adult patients were divided into three equal groups: unilateral, bilateral, and control groups. Each had 50 patients that were three-dimensionally analysed. The quantitative measurements involved three basal (molar basal width, premolar basal width, and arch depth), seven dentoalveolar (molar alveolar width, premolar alveolar width, inter-molar width, inter-premolar width, inter-canine width, arch length, and arch perimeter), and two dental (canine length and width) measurements. The qualitative measurements included four bone density areas (buccal, lingual, mesial, and distal) around the maxillary impacted canines., Result: Differences between the three groups were statistically different for the quantitative measurements involving the two basal variables (molar basal width and premolar basal width) and all measured dentoalveolar variables; these were smaller in the unilateral and bilateral groups compared with the control group (p < 0.001). Unilateral and bilateral impacted canine groups showed significantly wider and shorter canines than the control group (p < 0.001). The qualitative measurements (the four bone density areas) around unilateral and bilateral impacted canine groups showed significantly greater density than the control group (p < 0.001). There was no significant qualitative or quantitative difference between the unilateral and bilateral impacted canines. The three groups had no significant variations in terms of arch depth., Conclusion: Maxillary unilateral and bilateral canine impactions are associated with reduced basal and dentoalveolar dimensions as well as wider and shorter maxillary canines compared to normal peers. The quality of bone around unilateral and bilateral impacted maxillary canines is higher than in non-impacted cases. Unilateral and bilateral canine impactions have quite similar qualitative and quantitative parameters., (© 2022. The Author(s).)

Objective: This study aimed to evaluate the morphological and dimensional variations of the frontal air sinuses in a group of adolescent Caucasians and Chinese with different skeletal malocclusions in both genders., Materials and Methods: This retrospective study included 290 adolescent Caucasians and Chinese patients with 145 each. Each sample included 90 females and 55 males and was categorized based on ANB angle in reference to each population norms into 65 skeletal class I, 50 skeletal class II, and 30 skeletal class III malocclusions. All linear, angular, and surface area measurements of the frontal air sinuses were evaluated using lateral cephalometric radiographs and calculated using Winceph version 8 software. The frontal air sinus parameters were compared between genders and the two ethnic groups using an independent sample t-test. ANOVA with Tukey's post hoc tests were used to compare the frontal air sinus parameters between the three skeletal malocclusions., Result: The frontal air sinus width and surface area were found to be significantly greater in Caucasians when compared with Chinese patients. According to gender, the frontal air sinus length, width, and surface area, as well as the glabella convexity, were greater in males than females, while the frontal air sinus index (length/width) was significantly greater in females than males in both ethnic groups. In both ethnic groups, the frontal air sinus surface area was significantly greater in skeletal class III malocclusion when compared to skeletal class I and class II malocclusions in Caucasians (P = 0.0022) and Chinese (P = 0.0097). There was a weak-to-moderate correlation between the frontal air sinus parameters and the nasio, sella, and glabella positions (R = -0.56 to 0.62)., Conclusion: The frontal air sinus dimensions and surface area varied greatly in between ethnic groups, genders, and malocclusion types. The frontal air sinus parameters were correlated with nasion, sella, and glabella positions., Clinical Relevance: These findings could assist orthodontists, ENT specialist, and forensic medical investigators to focus on the size of frontal sinus during treatment planning, the relationship between the size of frontal air sinus and malocclusions, and age determination., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: The goal of this systematic review was to assess the available evidence regarding the skeletal and dentoalveolar effects of bi-maxillary skeletal anchorage devices (BMSADs) used in treating growing class II malocclusion patients., Methods: A comprehensive search was conducted on PubMed, Scopus, Science Direct, Web of Science, Cochrane, and LILACS up to November 2021, which was augmented by a manual search. The studies included were clinical trials (RCTs) and/or follow-up observational studies (retrospective and prospective). The outcomes of interest were the skeletal, dentoalveolar, and occlusal treatment-induced changes obtained from pre- and post-cephalometric measurements. The risks of bias of the included studies were assessed using an assessment tool from previous publications., Results: Out of 742 screened articles, only 4 were eligible and thus included in the qualitative synthesis. They showed a moderate overall risk of bias. The results are presented as mean changes in both the study and control groups. All studies reported retrusion of the maxillary base and advancement of the mandible (meaning reduced ANB angle). Three of the included studies reported an increase in the vertical jaw relation, which was contrary to what the fourth study reported. Three studies reported an increase in the maxillary incisors' inclination or position, while one study reported their retroclination. Proclination of the mandibular incisors happened in two studies, whereas the other two studies reported retroclination. The overjet was reduced in all included studies., Conclusion: Apart from the protrusive effects on the mandible, retrusive effects on the maxilla, and the consequent reduction of the overjet, BMSADs results in inconsistent skeletal and dentoalveolar effects. However, the current evidence is limited due to the variability in the biomechanics of the intermaxillary components, type of anchorage, and comparable groups in the included studies. Further RCTs with more standardized methodologies are highly encouraged., Clinical Relevance: BMSADs (using miniscrews or miniplates on both jaws) induces more skeletal than dentoalveolar effects. However, this must be practiced with caution, based on the benefit to risk (surgical insertion) ratio, and the limited evidence available in hand so far. Registration The protocol for this systematic review was registered at the International Prospective Register of Systematic Reviews (PROSPERO, No.: CRD42020199601)., (© 2022. The Author(s).)

Objective: Posterior teeth intrusion is one of the best treatment options for treatment of skeletal open bite in adults; the surrounding anatomical landmarks are one of the restraining factors. This study aimed to assess the vertical relationship between the maxillary posterior teeth (MPT) and the maxillary sinus floor (MSF) in different facial growth patterns in the Chinese adult population., Materials and Methods: Cone beam computed tomography images of 298 patients, 145 males and 153 females aged between 20 and 45 years, were analyzed. Based on Jarabak ratio and the mandibular plane inclination, the sample was categorized into 94 hyperdivergent, 102 hypodivergent, and 102 normodivergent facial patterns subjects. The vertical relationship between the root-apex distances were classified as favorable, indicating no contact (type 1), or unfavorable, indicating roots in contact (type 2) for the posterior teeth intrusion. The relationship in the unfavorable group was subdivided into three subgroups (T2C, T2LC, and T2P). Comparative statistical tests were done related to age, gender, tooth side, and type of multiplanar view (sagittal and coronal). The significant level was set to be P < 0.05., Results: There was a statistically significant difference in the mean distance between both genders in the hyperdivergent group (P < 0.001). The measured distance increased with age in all tooth roots (P < 0.001). In both sagittal and coronal views, the most frequent root scores were type 1 and type 2p (54.2%, 27.5%) and (55.1%, 21.4%), respectively. The hyperdivergent group demonstrated a higher prevalence of type 2P (31.6% and 25.5%), whereas the hypodivergent group showed a lower prevalence (25.1% and 19.2%); furthermore, the second molar's mesiobuccal root in hyperdivergent patients showed the closest distance to the maxillary sinus in sagittal and coronal views, 0.3 ± 3.7 and 0.4 ± 3.1 mm, respectively., Conclusions: Maxillary molars of hyperdivergent patients have the highest possible risk of root resorption due to the possible risk of cortical bone encroachment, while hypodivergent patients have the least possible risk., Clinical Relevance: Analysis of apex-sinus distances can be of great help for safe posterior teeth intrusion and providing correct and adequate treatment., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: To investigate the position of the upper central incisor roots (U1) relative to the incisive canal (IC) among subjects with maxillary dentoalveolar protrusion in various facial growth patterns., Materials and Methods: 240 cone beam computed tomography images of skeletal Class I and II maxillary or bimaxillary protrusive subjects with a mean age of 23.74 ± 3.73 years were enrolled according to their facial growth pattern. The IC volume was measured using Mimics 21 software (Materialise, Leuven, Belgium). The U1 inter-root distance, width of IC, and their proximity were estimated using Invivo6 software (Anatomage, San Jose, CA)., Results: The IC volume was slightly greater among the high angle facial group and female patients than the other groups. Overall, the IC width was greater than the U1 inter-root distance in 55.65%, 57.6%, and 65% among the average, low, and high angle facial groups, respectively, and in 56.5% and 62.9% of males and females, respectively. The overall anteroposterior (sagittal) distances between the U1 roots and IC were 4.36 ± 1.18, 4.78 ± 1.17, and 3.83 ± 0.90 mm among the average, low, and high angle facial groups, respectively., Conclusions: The high angle facial group and female patients showed slightly greater IC dimensions than the other groups. The overall maximum sagittal distances between the U1 and IC were around 5.5, 6, and 4.7 mm among the average, low, and high angle facial groups, respectively. The low angle facial group and male patients tended to have greater sagittal distances. Therefore, the present findings could serve as a guideline when a considerable amount of upper incisor retraction is planned for Class I or II maxillary or bimaxillary dentoalveolar protrusion patients., (© 2022 by The EH Angle Education and Research Foundation, Inc.)

Background: This study aimed to evaluate three-dimensionally the factors associated with adjacent teeth root resorption of palatally impacted canines., Methods: In this retrospective cross-sectional study, one-hundred and fourteen cone beam computed tomography scans with palatally impacted maxillary canines were evaluated for the presence of adjacent root resorption. Seven parameters were analyzed: alignment of maxillary incisors, presence of deciduous canines, first premolars' roots configuration, impacted canines rotation, angulation of impacted canine to the midline, contact relationship, and area of contact with adjacent teeth. The association between dependent and independent qualitative and quantitative variables was analyzed using chi-square and independent student's t-test, respectively. The multivariate analysis was performed using regression analysis. The significant value was set at P ≤ 0.05., Results: The overall incidence of vertical, horizontal impaction and adjacent root resorption were 92, 8 and 77.2%, respectively. The apical third was the most involved area (57%); resorption of a single tooth was found in 21.9% of the total sample. The most common resorbed teeth were lateral first premolars (24.6%), followed by central lateral incisors (20.2%), and lateral incisors (15.8%) of the total sample. The severity of resorption was highest in grade I (31.5%) and lowest in grade III (7.6%). Three variables showed significant differences between resorption and non-resorption groups namely; canine rotation (P < 0.013), contact relationship (P < 0.001), and area of contact with adjacent teeth (P < 0.001). Regression analysis revealed an association between adjacent root resorption and permanent canine rotation, adjacent premolars' roots configuration, contact relationship, and area of contact (P < 0.05)., Conclusion: Two-thirds of impacted maxillary canines showed a form of root resorption. The most commonly resorbed tooth was the lateral incisors while the least affected one was the central incisors with apical one-third being of the highest risk. The predisposing factors including the canine rotation, premolar with separated roots, contact relationship, and area of contact with adjacent teeth are to be considered for any interceptive treatment., (© 2022. The Author(s).)

Objectives: The objective was to evaluate the magnitude, incidence and possible factors of asymmetric expansion with a customized microimplant-supported rapid palatal expander (MARPE) in non-growing patients., Setting and Sample Population: This retrospective study included a sample of 49 patients (mean age: 23.9 ± 3.9 years) treated with a customized microimplant-supported rapid palatal expander. Based on the symmetry of expansion, the sample was divided into Group S (symmetric expansion group, n = 26) and Group A (asymmetric expansion group, n = 23)., Methods: Pre- and post-treatment cone-beam computed tomography (CBCT) images were superimposed to assess skeletal change in both studied groups. Seven variables were tested: unilateral crossbite, maxillary base cant, chin deviation, the initial asymmetrical position of the mid-palatal suture, split pattern of frontomaxillary suture, Angle's classification and dental arch crowding. Paired t-test and logistic regression analyses were utilized to evaluate the possible factors behind the asymmetric expansion., Results: There was a significant difference (P < .01) between the studied groups. The average expansion was 4.26 mm at the anterolateral maxillary walls (BB) and 3.83 mm at the greater palatine foramen region (GPF). The average expansion at the GPF was 90% of that at the BB. The frequency of asymmetric expansion was 46.9%. Among the seven tested variables, the presence of the initial asymmetric position of the mid-palatal suture is the only variable that showed correlation with asymmetric expansion., Conclusion: Initial asymmetric position of the mid-palatal suture is considered a contributing factor of skeletal asymmetric expansion following microimplant-supported rapid palatal expansion in skeletally comparable patients., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Understanding the anatomical relationship between the maxillary sinus floor (MSF) and the posterior maxillary teeth (PMT) is important when planning the orthodontic intrusion of the posterior teeth. This study aimed to determine the vertical relationship between posterior maxillary teeth and maxillary sinus floor in different skeletal classes in the Chinese adult population., Methods: This is a retrospective cross-sectional study involved cone beam computed tomography images of 298 adult patients (145 males and 153 females) between 20 and 45 years old. The sample was categorized according to A point, Nasion, B point (ANB) angle into 102 Class I, 102 Class II, and 94 Class III malocclusion. Non-parametric Wilcoxon Mann-Whitney U and Kruskal-Wallis tests were used to compare the studied groups. The Intra-class Correlation Coefficient (ICC) was used to assess the intra- and inter-observer reliability analysis., Results: Overall, there was a statistically significant difference in the mean distance between both genders (P < 0.001). The measured distance increased with age in all posterior tooth roots (P < 0.001). The root apex in the sagittal view appeared to be closer to the maxillary sinus than in the coronal view; 2.2 ± 4.3 and 3.1 ± 5.5 mm, respectively. The most frequent root scores were Type 1 and Type 2P. In both sagittal and coronal views, Class I demonstrated a higher Type 2P prevalence, whereas Class III showed a lower prevalence. The second molars' mesiobuccal root had the largest number of penetration in the three examined skeletal classes., Conclusions: Maxillary molars of Class I malocclusion with the majority of Type 2P root-sinus relationship have the highest possible risk of root resorption during molar intrusion due to cortical bone encroachment, while Class III malocclusion showed the least possible risk., (© 2022. The Author(s).)

Aim: This study sought to assess the fusion of spheno-occipital synchondrosis (SOS) in Chinese population using cone-beam computed tomography (CBCT)., Materials and Methods: This is a cross-sectional study in which data were randomly collected based on the pre-existing institutional records. Following selection criteria, the CBCT images of 500 patients aged 6-25 years (226 males and 274 females) were analyzed. Three-dimensional virtual models were oriented at a standardized position, then adjusted to the median sagittal plane (MSP) view. A four-stage scoring system was used; completely open, partially fused, semi-fused, or completely fused. The student's t -test, one-way ANOVA, Pearson correlation, and linear regression analysis were used and the significant level was set at ≤0.05., Results: The mean age of closure of stages 1, 2, 3, and 4 were 7.44, 9.62, 12.94, and 19.03 years in females, and 8.79, 11.13, 14.82, and 20.18 years in males, respectively. There was significantly strong positive correlation between spheno-occipital fusion and age (female: r = 0.853, male: r = 0.879; p <0.001), with 1.47 ± 0.33 years earlier fusion in females. All inter- and intra-stages mean ages were statistically significant in both genders. The transition age model demonstrated a mean age (in years) between stages 1-2 (10.1), stages 2-3 (12.79), and stage 3-4 (17.93) for males, and stages 1-2 (8.96), stages 2-3 (11.45), and stage 3-4 (16.69) for females., Conclusions: The present findings of SOS stages of fusion in both genders could guide age estimation and assessment of normal skeletal growth patterns and active skeletal growth period in the Chinese population., Clinical Significance: There is still controversy about the time to closure of the SOS because of population and assessment technique variations. This study could be used as a reference for the specific examined population during planning for dentofacial orthopedic and/or orthognathic surgery and dental implant prosthesis for both genders. Moreover, these finding may be useful for medical purposes.

Aim: The objective of the present study was to assess the accuracy and reproducibility of permanent dentition and dental arch measurements of three digital scanners compared with the gold standard, a physical plaster cast., Materials and Methods: In this cross-sectional study, the following records of 30 patients were used: 1) orthodontic physical plaster study cast (PPSC); 2) digitally scanned physical model (DSPM), 3) direct intraoral model scanned with a Trios color scanner; and 4) direct 3D CBCT digital model. The following 3D measurements were obtained: mesiodistal tooth dimensions; total tooth materials; dental arch perimeters; total arch lengths; and intermolar, interpremolar, and intercanine widths. The measurements on the three digital models were contrasted with those on the PPSC. Differences were tested using a dependent t test for intragroup comparisons. A P value of < 0.05 was considered statistically significant. Intraclass correlation coefficient was used to assess intra- and interexaminer reliability., Results: Except for the mesiodistal dimensions of the mandibular left central incisors (P < 0.001) and the mandibular intercanine width (P = 0.041), no statistically significant differences were found between the measurements made directly on the PPSC and those on the three digital models. The mean discrepancies between the methods ranged from as low as 0.003 mm to as high as 0.67 mm for the total tooth materials, and as low as 0.01 mm to as high as 0.37 mm for the total arch length. For the transverse dimension, the mean discrepancies ranged from as low as 0.3 mm for the maxillary intercanine width to as high as 0.5 mm for the mandibular intercanine width. However, these significant differences were not considered clinically significant., Conclusions: The DSPM, Trios color scanner digital model, and direct 3D CBCT digital model appear to be adequate, reliable, and time-saving alternatives to the PPSC when analyzed using a digital caliper.

Background: Gingival enlargement (GE) is one of the most common soft tissue problems encountered during fixed orthodontic treatment. Aims: This study aimed to evaluate the factors affecting GE in adolescents and young adults, compared with their normal peers., Subjects and Methods: This is a cross-sectional comparative study. The sample consisted of 329 subjects (ages 10-30 years) of both genders, which was divided into four main groups: The control group (G0) with no orthodontic treatment; subjects who underwent orthodontic treatment were divided according to treatment duration into G1 (4-12 months), G2 (13-24 months), and G3 (>24 months). The clinical examinations included the level of debris, calculus (simplified oral hygiene), and GE indices. Regression analyses were used to assess the GE association in all the studied groups., Results: The mean GE score increased significantly with increased treatment duration (0.42 ± 0.29 for G0 and 1.03 ± 0.52 for G3). GE scores of the lower arch were significantly higher in the anterior segment than in the posterior segment among all treatment groups. Regression analysis revealed that gender, age, oral hygiene, and treatment duration had a significant effect on GE (P < 0.05), while angle classification, overjet, overbite, treatment stage, bracket type, and therapeutic extraction did not show significant associations (P > 0.05)., Conclusion: Gender, age, oral hygiene, and treatment duration were the most important risk factors for GE during fixed orthodontic treatment., Competing Interests: None

Objectives: This cross-sectional comparative study investigated the effects of qat chewing habit on the radiographic bone density (RBD) and trabecular microstructure of temporomandibular joint condyles using cone beam computed tomography (CBCT)., Study Design: In total, 85 systemically healthy Yemeni males were included and divided into qat chewers (QCs; n = 41); and non-qat chewers (NQCs; n = 44). The participants responded to a structured questionnaire and underwent standardized clinical examination and CBCT scanning of the temporomandibular joint. Measurements of RBD and trabecular microstructure (trabecular thickness, trabecular separation, bone volume fraction, and fractal dimension) were performed. Statistical significance was established at P ≤ .05., Results: No statistically significant differences were found between QCs and NQCs in RBD or trabecular microstructure. The mean standard deviations and maximum values of trabecular separation on the nonchewing side for QCs were significantly lower compared to the corresponding values for NQCs (0.60 and 2.68 for QCs vs 0.72 and 3.05 for NQCs; P = .025 and .05, respectively). A comparison between chewing and nonchewing sides in QCs revealed no significant differences., Conclusions: Qat chewing habit induces insignificant changes in condylar RBD and trabecular microstructure as detected by CBCT. Further studies using advanced radiographic techniques are warranted., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To compare the effects of micro-osteoperforations (MOPs) vs piezocision (Piezo) in accelerating orthodontic tooth movement in adults., Setting and Sample Population: In this randomized, single-blinded, parallel-group, split-mouth clinical trial, 24 patients aged 15-40 years were recruited., Subjects and Methods: Patients were randomly allocated into two groups: MOPs and Piezo groups. One side of the maxilla was allocated randomly for treatment with one of these techniques, and the other side was treated conventionally to act as a split-mouth control. The rate of canine retraction was evaluated up to 3 months by three-dimensional digital models using a conventional labial appliance. Root resorption and bone height were evaluated using cone beam computed tomography., Results: The MOPs and Piezo groups showed a significantly higher rate of tooth movement after 3 months on the experimental sides than the control sides. However, the net movements in the MOPs and Piezo groups did not reveal a higher rate of tooth movement. Similarly, the overall net movement was -0.32 ± 1.14 and -0.55 ± 0.89 mm for MOPs and Piezo, respectively (P = .606). Regarding root resorption, the overall changes in intra- or intergroup comparisons were insignificant. Decreased canine palatal bone height was reported on the experimental side of the Piezo group (P = .015) after 3 months, but the overall changes were insignificant., Conclusions: The effect of MOPs and Piezo techniques in accelerating the orthodontic canine retraction was comparable to each other, and to the conventional methods. Neither technique caused root resorption or increased vertical bone loss., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: The purpose of this study was to three-dimensionally (3D) evaluate the morphological and positional features of the temporomandibular joint (TMJ) in adults with unilateral and bilateral posterior crossbite compared with aligned control subjects., Materials and Methods: This cross-sectional comparative study analysed cone beam computed tomography (CBCT) images of 90 adult subjects' divided into three equal groups: bilateral posterior crossbite (BCG), unilateral posterior crossbite (UCG) and control group (CG). 3D measurements of the TMJ included the following: (a) position, angulation and inclination of the mandibular condyles; (b) centralisation of the condyles in their respective mandibular fossae; and (c) volumetric measurements of the TMJ spaces. Intra- and intergroup differences were identified using the paired Student's t test and an analysis of variance (ANOVA) followed by Tukey's post hoc test, respectively., Results: Regarding the intra-group side-based comparisons, there were significant differences in the anterior and superior joint spaces and the anteroposterior condylar joint position in the UCG. Intergroup comparisons revealed significant differences in the vertical condylar inclination, medial condylar position, condylar width and height, and volumetric joint space between the unaffected side of the UCG and left sides of the other groups. There were significant differences in the anteroposterior condylar inclination, medial condylar position, condylar width and height, anterior, posterior, superior and volumetric joint spaces, and anteroposterior condylar joint position between the crossbite side of the UCG and the right sides of the other groups., Conclusion: Skeletal crossbite accompanied with characteristic morphological and positional TMJ features associated with unilateral posterior crossbite and are associated with side-specific TMJ asymmetry., (© 2021 John Wiley & Sons Ltd.)

The study sought to assess whether the soft tissue facial profile measurements of direct Cone Beam Computed Tomography (CBCT) and wrapped CBCT images of non-standardized facial photographs are accurate compared to the standardized digital photographs. In this cross-sectional study, 60 patients with an age range of 18-30 years, who were indicated for CBCT, were enrolled. Two facial photographs were taken per patient: standardized and random (non-standardized). The non-standardized ones were wrapped with the CBCT images. The most used soft tissue facial profile landmarks/parameters (linear and angular) were measured on direct soft tissue three-dimensional (3D) images and on the photographs wrapped over the 3D-CBCT images, and then compared to the standardized photographs. The reliability analysis was performed using concordance correlation coefficients (CCC) and depicted graphically using Bland-Altman plots. Most of the linear and angular measurements showed high reliability (0.91 to 0.998). Nevertheless, four soft tissue measurements were unreliable; namely, posterior gonial angle (0.085 and 0.11 for wrapped and direct CBCT soft tissue, respectively), mandibular plane angle (0.006 and 0.0016 for wrapped and direct CBCT soft tissue, respectively), posterior facial height (0.63 and 0.62 for wrapped and direct CBCT soft tissue, respectively) and total soft tissue facial convexity (0.52 for both wrapped and direct CBCT soft tissue, respectively). The soft tissue facial profile measurements from either the direct 3D-CBCT images or the wrapped CBCT images of non-standardized frontal photographs were accurate, and can be used to analyze most of the soft tissue facial profile measurements.

Objective : To three-dimensionally evaluate the upper pharyngeal airway spaces in adults with different anteroposterior and vertical skeletal malocclusions. Methods : In this retrospective study, three-dimensional airway volume and the minimum constricted areas of 120 adults were measured from cone beam computed tomography volume scans. The sample was divided into skeletal Class I and Class II and subdivided into average and long face malocclusions in each skeletal Class. Airway volumes of the naso-, palato-, and glossopharynx, and the minimum constricted area were measured and compared. Results : Skeletal Class II reduced glossopharyngeal airway volume and larger total minimum constricted area in average faces and more nasal minimum constricted area in long faces. Skeletal Class II with long face significantly increased palatopharyngeal and glossopharyngeal airway volumes as well as larger palatopharyngeal minimum constricted area ( p < 0.05). Conclusion : This paper found a likely association between jaw skeletal classification and airway dimensions.

The social habit of chewing qat (also known as khat) is widely practised in East Africa and the Arabian Peninsula. It has been linked with various oro-facial conditions, including temporomandibular joint disorders (TMD). This cross-sectional, comparative study sought to investigate the effects of qat chewing on temporomandibular joint (TMJ), using cone beam computed tomography (CBCT). A total of 85 Yemeni males were included. The participants were divided into two groups: Qat chewers (QC; n = 41) and non-qat chewers (NQC; n = 44). Relevant data were obtained using a structured questionnaire and standardised clinical examination. Additionally, CBCT images of the TMJs were obtained, and then, osteoarthritic changes and TMJ dimensions were analysed. SPSS 21 was used for statistical analyses, with a significant level was set at 0.05. Compared to NQC, a significantly higher proportion of QC presented with clinical signs of TMDs. The qualitative CBCT findings revealed significantly higher osteoarthritic changes in QC than in NQC: osteophyte (51.2% vs 22.7%; P = .008), subcortical sclerosis (48.8% vs 27.3%; P = .047), articular surface flattening (46.3% vs 6.8%; P = .009) and subcortical cysts (43.9% vs 4.5%; P < .001). However, CBCT quantitative findings (condylar dimensions) did not show significant differences between the two groups. The chewing side of the QC group showed slightly more changes compared to the non-chewing side. The results demonstrate that qat chewing has detrimental effects on TMJ manifested mainly as osteoarthritic changes. Further large-scale studies are recommended., (© 2020 John Wiley & Sons Ltd.)

Introduction: To three-dimensionally analyze the skeletal and pharyngeal airway changes induced by Twin Block (TWB) and Forsus Fatigue Resistance Device (FFRD) in skeletal Class II female patients compared with untreated controls., Materials and Methods: The study comprised 62 growing female patients with skeletal Class II malocclusion due to mandibular retrusion treated with either TWB (n = 23) or FFRD (n = 21), or neither (n = 18; controls). Pre- and posttreatment/observational cone beam computed tomography images were used to evaluate the treatment changes., Results: TWB induced more obvious mandibular skeletal changes and caused significant retrusive effects on the maxilla. Similarly, the sagittal and vertical jaw relationships were affected more obviously with TWB (P <0.001) compared to FFRD. Changes in oropharyngeal volume and minimal axial area were more obvious with TWB., Discussion: The TWB functional appliance induced significant skeletal and pharyngeal airway changes. These changes were more obvious relative to the slight changes induced by FFRD or by natural growth.

Objective: Considering that the available studies on prevalence of malocclusions are local or national-based, this study aimed to pool data to determine the distribution of malocclusion traits worldwide in mixed and permanent dentitions., Methods: An electronic search was conducted using PubMed, Embase and Google Scholar search engines, to retrieve data on malocclusion prevalence for both mixed and permanent dentitions, up to December 2016., Results: Out of 2,977 retrieved studies, 53 were included. In permanent dentition, the global distributions of Class I, Class II, and Class III malocclusion were 74.7% [31 - 97%], 19.56% [2 - 63%] and 5.93% [1 - 20%], respectively. In mixed dentition, the distributions of these malocclusions were 73% [40 - 96%], 23% [2 - 58%] and 4% [0.7 - 13%]. Regarding vertical malocclusions, the observed deep overbite and open bite were 21.98% and 4.93%, respectively. Posterior crossbite affected 9.39% of the sample. Africans showed the highest prevalence of Class I and open bite in permanent dentition (89% and 8%, respectively), and in mixed dentition (93% and 10%, respectively), while Caucasians showed the highest prevalence of Class II in permanent dentition (23%) and mixed dentition (26%). Class III malocclusion in mixed dentition was highly prevalent among Mongoloids., Conclusion: Worldwide, in mixed and permanent dentitions, Angle Class I malocclusion is more prevalent than Class II, specifically among Africans; the least prevalent was Class III, although higher among Mongoloids in mixed dentition. In vertical dimension, open bite was highest among Mongoloids in mixed dentition. Posterior crossbite was more prevalent in permanent dentition in Europe.