Basal and dentoalveolar transverse parameters in different sagittal and vertical malocclusions in adults: a comparative study.

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.

Evaluation of an objective staging system for assessment of cervical vertebral maturation.

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.

Recommendations for standard criteria for the positional and morphological evaluation of temporomandibular joint osseous structures using cone-beam CT: a systematic review.

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.

Dimensional and positional temporomandibular joint osseous characteristics in normodivergent facial patterns with and without temporomandibular disorders.

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.

Quantitative and qualitative condylar changes following stabilization splint therapy in patients with temporomandibular joint disorders.

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 mm2 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.

Three-dimensional relationship between the degree of bilateral impacted mandibular third molars angulation and the mandibular dental arch parameters: a cross-sectional comparative study.

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 2nd 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 2nd MW. A significant negative correlation was observed between IM3M BL° and inter 1st MW and 2nd 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 1st and 2nd inter-molar width. The increase in mesiodistal angulations was generally related with increased anterior teeth crowding and 2nd 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.

Effect of the vertical facial pattern on the developmental relationship between the nasal bone and maxillary central incisors.

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.

Comparison of three-dimensional maxillary growth across spheno-occipital synchondrosis maturation stages.

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.

Three dimensional evaluation of the skeletal and temporomandibular joint changes following stabilization splint therapy in patients with temporomandibular joint disorders and mandibular deviation: a retrospective study.

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.

Morphological and dimensional variations of the frontal air sinuses in a group of adolescent Caucasians and Chinese in different skeletal malocclusions: a cross-sectional cephalometric study.

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.

Orthodontic camouflage versus orthodontic-orthognathic surgical treatment in borderline class III malocclusion: a systematic review.

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.

Predictive factors associated with adjacent teeth root resorption of palatally impacted canines in Arabian population: a cone-beam computed tomography analysis.

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.

Skeletal and dentoalveolar effects of class II malocclusion treatment using bi-maxillary skeletal anchorage: a systematic review.

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).

Comparison of spheno-occipital synchondrosis maturation stages with three-dimensional assessment of mandibular growth.

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.

Dimensional and Positional Characteristics of the Temporomandibular Joint of Skeletal Class II Malocclusion with and without Temporomandibular Disorders.

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.

Evaluation of Spheno-occipital Synchondrosis Fusion in Chinese Population Using CBCT: A Cross-sectional Study.

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.

Cone beam computed tomography findings in temporomandibular joint of chronic qat chewers: Dimensional and osteoarthritic changes.

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.

Perception of facial, dental, and smile esthetics by dental students.

OBJECTIVE: To comprehensively assess dental students' perception of facial, dental and smile esthetics and to assess whether such a perception varies by gender, clinical training, and Grade Point Average (GPA). MATERIALS AND METHODS: Series of photographs were digitally manipulated involving three facial, two smile, four dental, and one gingival components. Students in preclinical and clinical levels evaluated the original and manipulated images using a visual analogue scale scored from 1 to 5 where 5 is the standard image and 1 is the least pleasant one. The responses were then analyzed using Mann-Whitney test. A P value of < .05 was considered significant. RESULTS: Four hundred and eight dental students participated in this study. With regard to the overall esthetics, males and clinical students scored higher than females and preclinical students, respectively, did. With regard to the individual esthetic components, males had significantly higher scores in buccal corridors, midline shift, clinical crown width, and gingival marginal height, while females had significantly higher score in median diastema (P < .05). Clinical students had a better perception of facial asymmetry, gingival display, buccal corridors, and clinical crown width compared to the preclinical students. Effect of GPA was minimal and even contradictory; students with lower GPA had a better perception of midline deviation and occlusal canting than those with higher GPA scores. CONCLUSIONS: Male dental students, and unexpectedly unlike females, have a better perception of facial and dental esthetics. Unlike GPA, whose effect was minimal, clinical training has a substantial positive effect on the assessment of beauty. CLINICAL SIGNIFICANCE: Appropriate perception of facial, dental and smile esthetics by dental students is of paramount importance for providing adequate dental services and for improving and polishing their professionalism.© 2018 Wiley Periodicals, Inc.

Changes in Soft Tissue Profile After Orthodontic Treatment With and Without Extraction: A Systematic Review and Meta-analysis.

OBJECTIVE: The objective of this systematic review and meta-analysis was to evaluate the soft tissue changes in adult orthodontic patients who received extraction treatment in comparison to their counterparts who received nonextraction orthodontic treatment. METHODS: Electronic databases (CENTRAL-Cochrane Register of Controlled Trials, PubMed, Embase, EBESCOhost, LILACS, and Google Scholar) were searched up to March 2015. Handsearching was performed too. The selection process included controlled trials (prospective or retrospective and randomized or nonrandomized) on adult patients receiving orthodontic extraction treatment compared within the same study to a group treated without extraction. The outcomes of interest were the changes in linear and angular cephalometric measurements specific for soft tissue profile. Studies which fulfilled the selection criteria were retrieved. They were assessed for methodological quality based on a validated checklist. Studies of moderate to high quality were included. RESULTS: Of the nine full texts which fulfilled the selection criteria, 5 were eligible for the quantitative analysis; they scored a moderate quality. Meta-analysis showed a significant increase regarding the nasolabial angle, upper lip thickness, labrale superioris to E-Line, and labrale inferioris to E-line in the extraction group, suggesting the flattening of the profile following extraction treatment. CONCLUSION: A significant retraction of the lips and an increase in the nasolabial angle are associated with extraction protocols, but the degree to which these changes are considered detrimental/beneficial to the profile could be affected by different factors. Since these finding are based on studies of moderate quality, future research with well-conducted methodologies are highly recommended.

The relationship between the dimensions of frontal air sinus and skeletal malocclusions: A systematic review and meta-analysis.

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.