Pilot study for three-dimensional cephalometric Enlow's counterpart analysis: Vertical track. Two-dimensional and three-dimensional comparison.

BACKGROUND: The introduction of cone beam computed tomography (CBCT) in dentistry has given orthodontists the possibility of studying craniofacial structures in three dimensions. Despite the possibility to obtain lateral cephalograms synthesized from CBCT, this approach still does not provide a fully three-dimensional evaluation of the patient's anatomy. While there has been some success in adapting traditional two-dimensional cephalometric analyses to three dimensions, the specific application of Enlow's cephalometric analysis using CBCT remains unexplored. AIM: This pilot study aims to introduce a novel approach for performing Enlow's vertical track analysis using CBCT images. MATERIALS AND METHODS: Eighteen CBCT images of skeletal Class I (ANB = 2 ± 2) subjects (12 males and 6 females, aged from 9 to 19 years) with no history of previous orthodontic treatment were selected. For each subject, 2D Enlow's vertical track analysis was performed on lateral cephalograms extracted from the CBCT images, and separately, 3D vertical track analysis was directly performed on the CBCT images. To validate the proposed method, we compared the differences between the posterior vertical counterpart (PVC) and the middle vertical counterpart (MVC), as well as between the middle vertical counterpart (MVC) and the anterior vertical counterpart (AVC), as obtained from both the two-dimensional and three-dimensional analyses. The Kolmogorov-Smirnov normality test was applied for each variable to check whether data were normally distributed and a paired Student's t-test was performed. The level of statistical significance was .05. RESULTS: The comparison between three-dimensional PVC-MVC (-0.43 ± 0.37 cm) and two-dimensional PVC-MVC (-0.53 ± 0.36 cm) revealed no statistical difference (P = .27). Similarly, no significant difference (P = .28) was observed between two-dimensional MVC-AVC (-0.56 ± 0.34 cm) and three-dimensional MVC-AVC (-0.47 ± 0.37 cm). CONCLUSIONS: The method proposed by this study to realize the vertical track analysis on 3D images is valid and superimposable on that described by Enlow on lateral cephalograms.

Assessment of Nasal Aesthetic Parameters in Patients with Unilateral Cleft Lip and Palate - A Retrospective Study.

OBJECTIVES: To assess and compare the deviating nasal cephalometric parameters of patients with unilateral cleft lip and palate (UCLP) with a control group. The study also aims to correlate the deviating cephalometric parameters with two aesthetic scoring systems. DESIGN: A retrospective study. SETTING: Dental college and hospital. PARTICIPANTS: Pre-treatment lateral cephalograms and extra oral photographs of 20 adult patients with repaired UCLP presenting for orthodontic treatment. 20 patients with age and type of malocclusion matched control were selected. MAIN OUTCOME: The nasal cephalometric parameters of patients with UCLP and a control group were compared. The nasolabial region of patients with cleft lip and palate (CLP) was scored using Asher McDade Aesthetic Index (AMAI) and Cleft Aesthetic Rating Scale (CARS). The scoring was done by six different groups assessors to study their perception of the nasolabial region. Correlation between cephalometric parameters and the aesthetic scores was done. RESULTS: The study found significant differences in nasal length (P = .003) and depth (P < .001) between UCLP and the non-cleft control group. In the aesthetic assessment, orthodontist gave the least scores, while layman group scored the highest. The CARS nose aesthetic scores showed statistically significant high, negative correlation with the nasal length (P = .01). CONCLUSION: The cephalometric parameters and the aesthetic indices can be aid the orthodontists in the assessment of nasolabial aesthetics and additionally refer for further definitive rhinoplasty to improve the patient's overall facial aesthetics.

Alterations in Sphenoid Anatomy in Craniosynostosis: Implications for Fronto-Orbital Advancement.

OBJECTIVE: Fronto-orbital advancement involves removal of the fronto-orbital bandeau. Visualization of the saw blade is lost as it passes through the fronto-orbital-sphenoid junction (FOSJ), placing the temporal lobe at risk of injury. We aim to provide a 3D analysis of the space surrounding this osteotomy to differentiate various types of craniosynostoses. DESIGN: Retrospective cohort. SETTING: Institutional. PATIENTS: Thirty patients with isolated unicoronal synostosis, nonsyndromic bicoronal synostosis, metopic synostosis, Apert syndrome, Crouzon syndrome, and Muenke syndrome. INTERVENTIONS: CT scans conducted between 2 months to 2 years of age were 3D reconstructed to compare craniometrics against normal controls. MAIN OUTCOME MEASURE(S): Craniometrics. RESULTS: The mean bone thickness of the FOSJ at the level of the supraorbital rim was significantly small for the Apert, unicoronal and bicoronal groups. The mean vertical height of the middle cranial fossa from the lesser sphenoid wing was significantly greater in the unicoronal group. The mean vertical height of the tip of the temporal lobe from the lateral sphenoid ridge was greater in the unicoronal, isolated bicoronal, and Apert groups. The mean corneal protrusion beyond the lateral orbital rim was significantly greater in the Apert and unicoronal groups. The mean horizontal depth of the orbit was smallest in the Apert group. The mean vertical distance between the dacryon and the foramen cecum, and the mean volume of temporal lobe beneath the sphenoid shelf were the largest in the Apert group. CONCLUSIONS: Patients with Apert syndrome have the most unfavorable morphology of the anterior and middle cranial fossae.

Perception of maxillary incisor inclination and its correlation with dental cephalometric measurements.

OBJECTIVE: To correlate the clinical perception of maxillary incisor inclination from photographs of the smiling face with cephalometric measurements, using conventional incisor axis reference points and crown reference points. DESIGN: Cross-sectional study. SETTING: Department of Orthodontics, School of Dentistry, University of Lisbon (Portugal). PARTICIPANTS: Eight orthodontists. METHODS: The perception of maxillary incisor inclination of 47 female patients (mean age 23.4 ± 1.5 years) was evaluated by eight orthodontists. The participants' photographs (smiling frontal, smiling three-quarter and smiling profile) were shown to each assessor and a continuous visual analogue rating scale was used to assess the perception of maxillary incisor inclination. Pearson's correlation and linear regression were calculated between each cephalometric measurement and the perception of incisor inclination. RESULTS: Anatomical crown inclination measurements U1ac-FH (r = 0.854; P < 0.01) and U1ac-SN (r = 0.845; P < 0.01) had the highest correlation values with the assessors' perception of maxillary incisor inclination. Conventional incisor axis measurements showed the lowest correlation values (r = 0.668-0.756). CONCLUSION: Cephalometric measurements of the labial surface of the anatomical crown of the maxillary incisors showed the strongest correlations with the clinical perception of maxillary incisor inclination from photographs. For optimal aesthetics, the inclination of the labial surface of maxillary incisor crown should be evaluated.

'Study of the maxillary yaw on cone beam computed tomography: A preliminary report and comparison between two different dento-skeletal malocclusions'.

OBJECTIVES: To assess the skeletal and dental maxillary transverse compensation (yaw) on the cone beam computed tomography (CBCT) three-dimensional reconstructed image of the skull in two groups of patients, both clinically affected by a class III malocclusion with deviation of the lower midline. MATERIALS AND METHODS: An observational retrospective study was designed to analyse differences in two groups of patients, the first one was composed by patients affected by horizontal condylar hyperplasia, the second one by patients affected by dento-skeletal asymmetric class III malocclusion. Each group was composed by 15 patients. Transverse analysis was performed by measuring five landmarks (three bilateral and two uneven) with respect to a mid-sagittal plane; sagittal analysis was performed by measuring the sagittal distance on the mid-sagittal plane between bilateral points. Means were compared through inferential analysis. RESULTS: In the condylar hyperplasia group, all differences between the two sides were not statistically significant, nor for canines' difference (P = .0817), for molars (P = .1105) or for jugular points (.05871). In the class III group, the differences between the two sides were statistically significant for molars (P = .0019) and jugular points (P = .0031) but not for canines (P = .1158). Comparing the two groups, significant differences were found only for incisors' midline deviation (P = .0343) and canine (P = .0177). CONCLUSION: The study of the yaw on CBCT should be integrated into three-dimensional cephalometry and could help in differentiating the various malocclusion patterns.

Association of temporomandibular joint osteoarthrosis with dentoskeletal morphology in males: A cone-beam computed tomography and cephalometric analysis.

OBJECTIVE: The objective of the study was to assess the differences in dentoskeletal morphology in males with and without temporomandibular joint osteoarthrosis (TMJOA). METHODS: Three hundred seventy-one male participants seeking orthodontic treatment were enrolled in this cross-sectional study. Each participant's osseous status was evaluated using cone-beam computed tomography (CBCT) and classified into normal (N = 104), indeterminate for TMJOA (N = 110) and TMJOA (N = 157) groups. The dentoskeletal characteristics were evaluated using cephalograms. Stratified analysis was performed based on age and skeletal pattern. Descriptive statistics and one-way analysis of variance were performed to investigate dentoskeletal differences among groups. P < .05 was considered statistically significant. RESULTS: The differences in posterior cranial base length, FMA, MP-OP, anterior facial height, articular angle, ramus height and L1-MP were statistically significant. After stratification by age, the differences in FMA, maxillomandibular angle, posterior facial height, facial height ratio, gonial angle and mandibular body length were statistically significant in adults. No statistical difference except for articular angle was observed in adolescents. After stratification by skeletal pattern, statistical differences were mainly apparent in skeletal Class II adults. CONCLUSION: Males with TMJOA showed a posteriorly positioned and backward-rotated mandible, especially in skeletal Class II adults. Compared with women, the craniofacial morphology of men is less affected by TMJOA. The association between TMJOA and craniofacial morphology also varied across different age groups and skeletal patterns. Prospective studies are required to clarify the cause-effect relationship between TMJOA and craniofacial morphology in males.

Effects of osseous structure based on three-dimensional reconstructive imaging evaluation in the assessment of temporomandibular joint disc position.

OBJECTIVES: This pilot morphological study aimed to investigate the association between anterior disc displacement (ADD) and the status of the mandibular condyle and articular fossa. MATERIALS AND METHODS: Thirty-four patients were divided into a normal articular disc position group and an ADD with and without reduction group. Images reconstructed were used to determine multiple group comparisons of these three different types of disc position, and the diagnostic efficacy for the morphological parameters with significant group difference was analyzed to assess. RESULTS: The condylar volume (CV), condylar superficial area (CSA), superior joint space (SJS), and medial joint space (MJS) all exhibited obvious changes (P < 0.05). Additionally, they all had a reliable diagnostic accuracy in differentiating between normal disc position and ADD with an AUC value from 0.723 to 0.858. Among them, the CV, SJS, and MJS (P < 0.05) had a significantly positive impact on the groups by analysis of multivariate logistic ordinal regression model. CONCLUSIONS: The CV, CSA, SJS, and MJS are significantly associated with different disc displacement types. The condyle in ADD exhibited altered dimensions. These could be promising biometric markers for assessing ADD. CLINICAL RELEVANCE: The morphological changes of mandibular condyle and glenoid fossa were significantly influenced by the status of disc displacement, and condyles with disc displacement had three-dimensionally altered condylar dimensions, irrespective of age and sex.

Heritability of cephalometric variables of airway morphology in twins with completed active growth.

BACKGROUND: The interplay between genetic and environmental impacts on dental and facial morphology has been widely analyzed, but little is known about their relative contributions to airway morphology. The aim of this study was to evaluate the genetic and environmental influences on the cephalometric variables of airway morphology in a group of postpubertal twins with completed craniofacial growth. MATERIALS AND METHODS: The materials comprised lateral head cephalograms of 94 pairs of twins (50 monozygotic, 44 dizygotic) with completed craniofacial growth. Zygosity was determined using 15 specific DNA markers. The computerized cephalometric analysis included 22 craniofacial, hyoideal, pharyngeal structural linear and angular variables. Genetic analysis and heritability estimation were performed using maximum likelihood genetic structural equation modeling (GSEM). Principal component analysis (PCA) was used to assess the correlations between cephalometric measurement variables. RESULTS: Upper airway dimensions showed moderate to high genetic determination (SPPW-SPP and U-MPW: a2 = 0.64 and 0.5, respectively). Lower airway parameters showed only common and specific environmental determination (PPW-TPP a2 = 0.24, e2 = 0.38; LPW-V c2 = 0.2, e2 = 0.63; PCV-AH c2 = 0.47, e2 = 0.28). The relationship between the maxilla and the hyoid bone (for variables PNS-AH, ANS-AH d2 = 0.9, 0.92, respectively) showed very strong additive genetic determination. The size of the soft palate was affected by additive and dominant genes. Its length (SPL) was strongly influenced by dominant genes, while its width (SPW) showed a moderate additive genetic influence. Owing to correlations in the behavior of variables, the data could be expressed in 5 principal components that jointly explained 36.8% of the total variance. CONCLUSIONS: The dimensions of the upper airway are strongly determined by genes, while the parameters of the lower airway depend mainly on environmental factors. TRIAL REGISTRATION: The protocol has been approved by the Kaunas Regional Ethical Committee (No. BE - 2-41., May 13, 2020).

Effect of SEC III protocol on upper airway dimensions in growing class III patients: a retrospective study.

BACKGROUND: The primary objective of the study was to evaluate the effects of SEC III (Splints, Class III Elastics, and Chin cup) protocol on the upper airway dimensions using lateral cephalometric radiographs. The secondary objectives were to evaluate the skeletal and dental effects of the SEC III protocol using lateral cephalometric radiographs. METHODS: The pre- and post-treatment lateral cephalometric radiographs of 24 patients treated using the SEC III protocol were used to address the aim of the study. Children in the pre-pubertal (CS-1 or CS-2) or circumpubertal (CS-3 or CS-4) skeletal maturation stage and having class III dentoskeletal malocclusion were included in the study. Patients with a history of previous orthodontic treatment, maxillofacial surgery or trauma, tonsillectomy, adenoidectomy, or craniofacial malformations were excluded. The pre-treatment and post-treatment lateral cephalometric radiographs were traced, then airway measurements, skeletal measurements, and dental measurements were performed. The results were analysed using paired samples t-test or Wilcoxon signed rank test according to the data normality. RESULTS: Data of 6 males and 18 females were analysed (Mean age = 11.21 ± 1.02 years). Duration of active treatment was 5.75 ± 1.03 months. Treatment using SEC III protocol resulted in a significant increase in ANB angle (2.92 ± 1.50 degrees, p < 0.001) and Wits appraisal (3.31 ± 1.99 mm) (p < 0.001). The increase in the mandibular plane angle (0.75 ± 1.42 degrees, p = 0.02) and the maxillary length (2.29 ± 2.69 mm, p < 0.001) was statistically significant. Contrarily, the mandibular length did not change significantly (p = 0.10). The maxillary incisors were significantly proclined (4.38 ± 4.28 degrees; p < 0.001), while the mandibular incisors were significantly retroclined (-5.79 ± 6.21 degrees; p < 0.001) following treatment. The change in the nasopharyngeal airway and the retropalatal airway was not statistically significant. The middle and inferior pharyngeal space (retroglossal airway) significantly decreased by 1.33 ± 1.97 mm (p = 0.003) and 1.96 ± 2.48 mm (p = 0.001), respectively. CONCLUSIONS: Early class III correction using SEC III protocol reduced the retroglossal airway dimensions but did not affect the nasopharyngeal and retropalatal airway dimensions. Correction of the class III dentoskeletal relationship was obtained through both skeletal and dental changes.

Accuracy of conventional versus cone-beam CT-synthesised lateral cephalograms for cephalometric analysis: A systematic review.

OBJECTIVE: To assess the accuracy of cone-beam computed tomography (CBCT)-synthesised lateral cephalograms (CSLCs) compared with conventional lateral cephalograms for cephalometric analysis in human participants and skull models. METHODS: The authors performed a search of PubMed, Scopus, Google Scholar and Embase databases on 4 October 2021. Included studies met the following criteria: published in English; compared conventional lateral cephalograms and CSLCs; assessed hard- and soft-tissue landmarks; and were performed on human or skull models. Data extraction from eligible studies was performed by two independent reviewers. The quality of evidence was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist tool - diagnostic accuracy studies. RESULTS: A total of 20 eligible articles were included in this systematic review. Of these 20 studies, 17 presented with a low risk of bias, while three were found to have a moderate risk of bias. Hard- and soft-tissue analyses were evaluated for each imaging modality. The findings reveal that CSLCs are accurate and comparable to conventional lateral cephalograms for cephalometric analysis and demonstrate good inter-observer reliability. Four studies reported a higher accuracy with CSLCs. CONCLUSION: Overall, the diagnostic accuracy and reproducibility of CSLCs were comparable to conventional lateral cephalograms in cephalometric analysis. It is justified that patients who have an existing CBCT scan do not need an additional lateral cephalogram, minimising unnecessary radiation exposure, expenses and time for the patient. Larger voxel sizes and low-dose CBCT protocols can be considered to minimise radiation exposure. REGISTRATION: This study was registered with PROSPERO (CRD42021282019).

Heritability of facial soft tissue growth in mono- and dizygotic twins at 12 and 17 years of age: A retrospective cohort study.

OBJECTIVE: The purpose of this investigation of untreated monozygotic and dizygotic twins was to identify the genetic and environmental components to the facial soft tissue growth. SETTINGS AND SAMPLE POPULATION: The sample consisted of 52 untreated monozygotic twins (36 male and 16 female) and 46 untreated dizygotic twins (23 male and 23 female) from the Forsyth Moorrees Twin Study (1959-1975). MATERIALS AND METHODS: Lateral cephalograms were taken at 12 and 17 years of age and traced to analyse facial convexity, nasolabial angle, upper and lower lip thickness, upper and lower lip profile and nose prominence. The genetic and environmental components of variance were analysed with structural equation modelling for multilevel mixed-effects model. RESULTS: At 12 years of age, strong additive genetic influence was seen for facial convexity (70%), upper lip profile (66%) and nose prominence (65%), whereas strong dominant genetic components were found for upper lip thickness (56%). Nevertheless, under unique environment influence were nasolabial angle (58%), lower lip profile (51%) and lower lip thickness (64%). At 17 years of age, only upper lip thickness (55%) and nose prominence (84%) were under strong additive genetic control, while the rest of the variables were under strong dominant genetic control. The only exception was lower lip thickness (61%), which is still influenced by the unique environment. CONCLUSION: Although monozygotic/dizygotic twins share at least part of their genome, at both times either additive, dominant or environmental components were found. Nevertheless, at 17 years of age most of the variables are either under additive or dominant genetic influence.

Skeletal and dentoalveolar characteristics of maxillary lateral incisor agenesis patients: a comparative cross-sectional study.

BACKGROUND: The aim of the study was to evaluate the cephalometric and dentoalveolar characteristics of maxillary lateral incisor agenesis patients, and to compare the findings to a matched control group without tooth agenesis, excluding third molars, from the same population. METHODS: The pre-orthodontic records of 72 non-growing patients, who were treated at the Orthodontic Department, Faculty of Dentistry, Alexandria University, were used to address the aim of this retrospective study. Patients having unilateral or bilateral maxillary lateral incisor agenesis, with no history of previous orthodontic treatment, congenital craniofacial malformations, facial trauma, or surgeries were divided into two test groups based on the pattern of maxillary lateral incisors agenesis (group I: unilateral (UMLIA), group II: bilateral (BMLIA)). A control group (group III (CTRL)) having a complete set of permanent dentition (excluding third molars), and having no dental anomalies was age-matched with the test groups. Measurements were performed on the pre-orthodontic lateral cephalometric radiographs and the pre-orthodontic digital dental casts. The measured variables were compared between the groups using one-way ANOVA and Kruskal Wallis tests according to the normality of the variable. In case of significant results, both tests were followed by multiple pairwise comparisons using Bonferroni adjusted significance level. Significance level was set at P < 0.05. RESULTS: BMLIA group showed a smaller SNA angle and maxillary length, a more negative ANB angle and Wits appraisal, and a larger Maxillo-mandibular differential than UMLIA and/or CTRL group. The dental and soft tissue cephalometric measurements did not show any significant differences between the groups. Dentoalveolar cast measurements showed that BMLIA patients presented with significantly smaller maxillary inter-canine width than UMLIA and CTRL patients. CONCLUSIONS: Cephalometric analysis has shown that subjects with BMLIA have a statistically significant reduced ANB and maxillary length. Tooth eruption may play a role in the development of the maxillary arch.

Correlation of lip profile preferences in Pakistani population; and its comparison with orthodontic norms.

OBJECTIVE: To determine the most desired lip profile and compare the subjective sense of aesthetics among orthodontists, general dentists and the general population. METHODS: The cross-sectional study was conducted at the Orthodontic Department of the Armed Forces Institute of Dentistry, Rawalpindi, Pakistan, from January 1 to February 25, 2020, and comprised different silhouettes for each gender with increasing lip procumbence from -6mm to +6mm with respect to Rickett's E-line which were created using Photoshop CS 8.0 after cephalometric analysis of 20 cephalograms. The sample comprised an equal number of orthodontists in group A, general dentists in group B and orthodontic treatment-seekers in group C with equal representation of the two genders. Data was analysed using SPSS 24. RESULTS: Of the 180 subjects, there were 60(33.3%) in each of the three groups, with 30(50%) males and as many females in all the groups. All the three groups preferred the average lip profile for males (p=0.018) and 2mm procumbent lips for females (p=0.008). There was significant difference of opinion between groups A and C (p=0.034) and between groups B and C (p=0.022). CONCLUSIONS: There was found to be a marked difference of opinion among the orthodontists, the general dentists and the orthodontic treatment-seekers regarding the desired lip profile.

A heuristic model for cephalometric diagnosis of sagittal dysplasia.

OBJECTIVE: To identify the best-suited cephalometric parameter for assessing the sagittal skeletal discrepancy in the Indian population. DESIGN: An in vitro, observational, single-blinded, retrospective study. SETTING: Department of Orthodontics and Dentofacial Orthopaedics. METHODS: A total of 94 lateral cephalograms were used in this study. The study involved one key person and two examiners. The key person collected the radiographs, coded, analysed and classified them into three groups (skeletal classes I, II and III). Subsequently, the coded radiographs were independently analysed by the two examiners. They classified the cases by matching a minimum of 6 out of 11 parameters. On completion of diagnosis by the examiners, the samples were decoded and matched with the original diagnosis given by the key person. The samples in which identification of a particular cephalometric parameter matched the original evaluation as given by the key person was regarded as correctly diagnosed. The number of correctly assessed cases was used to judge the diagnostic performance of all the parameters in all the cases. Cross-validation of the method was performed, and a diagnostic algorithm was developed for diagnosis. RESULTS: ß angle and Pi angle showed a positive predictive value of 1 in both skeletal class I and II cases. ANB angle, W angle and HBN angle showed a positive predictive value of 1 in skeletal class III cases. CONCLUSION: No single cephalometric parameter can independently be used to diagnose sagittal skeletal discrepancy in all cases. However, a conclusive diagnosis on the type of sagittal skeletal malocclusion can be made by using a simple and easy to use diagnostic algorithmic process having a combination of cephalometric parameters.

Can anteroposterior skeletal pattern be determined from a silhouetted profile photograph? A cross-sectional study.

OBJECTIVE: To determine the degree to which the anteroposterior (AP) skeletal jaw relation can accurately be determined from a silhouetted clinical profile photograph and whether the level of agreement is influenced by patient vertical proportions. DESIGN: Cross-sectional study. SETTING: University Dental Hospital of Manchester, United Kingdom. PARTICIPANTS: Specialist orthodontists. METHOD: Eight specialist orthodontists assessed 37 silhouetted profile photographs of individuals aged 11-19 years and determined the class and severity of AP skeletal pattern. These assessments were compared to corresponding lateral cephalometric radiographs, where ANB values, supplemented by an Eastman Correction and a Wits Appraisal, where appropriate, were used for sagittal skeletal classification. RESULTS: The agreement between silhouette and cephalometric AP determination yielded a weighted kappa score of 0.207 (95% confidence interval [CI] 0.135-0.278), which indicates only a fair level of agreement. The silhouetted sagittal skeletal pattern classification, along with severity, agreed with the lateral cephalometric radiograph in 29% of instances. Class III individuals were identified correctly 19.2% of the time. There was a statistically significant difference in kappa scores between the high angle (K= 0.439; 95% CI 0.310-0.568) and low angle (K = 0.068; 95% CI 0.007-0.130) patients (P < 0.001), as well as the high and average angle (K= 0.151; 95% CI 0.031-0.270) patients (P < 0.05). CONCLUSION: AP skeletal pattern, as determined from a lateral cephalometric radiograph, has only a fair level of agreement to that from a silhouetted profile photograph. Vertical proportions were shown to have a significant effect on the determination of the sagittal skeletal pattern and class III skeletal patterns were shown to be the most difficult to identify from profile silhouettes.

Reliability of Frankfort Horizontal Plane with True Horizontal Plane in Cephalometric Measurements.

INTRODUCTION: The purpose of the study is to determine reliability of true horizontal (TH) plane with Frankfort horizontal (FH) plane in cephalometric measurements. MATERIALS AND METHODS: One hundred lateral cephalograms were collected and traced using FACAD software, all cephalometric measurements which included FH plane as reference planes were used in this study. Cephalometric tracing was done with FH plane as reference plane and another set of measurements with TH plane as reference plane was done. Statistical tests were done using independent sample t-test (p <0.05). RESULTS: Results of an independent t-test revealed a statistically insignificant difference that was observed for all the parameters assessed (p <0.05). Both angular and linear measurements showed an insignificant difference between FH and TH. CONCLUSION: Within the limitations of the study, the results show that the FH plane is closest and as reliable as the TH plane. The variation of FH was least for all the parameters assessed.

Changes in the upper airway, hyoid bone and craniofacial morphology between patients treated with headgear activator and Herbst appliance: A retrospective study on lateral cephalometry.

BACKGROUND: The present study compared the treatment changes in the upper airway, hyoid bone position and craniofacial morphology between two groups of children with skeletal class II malocclusion treated with the headgear activator (HGA) and Herbst appliance (Herbst). SETTING AND SAMPLE POPULATION: Orthodontic population from the Faculty of Dentistry of the University of Hong Kong. METHODS: Thirty-four skeletal class II patients treated with the HGA (17 patients, mean age 10.6 ± 1.5 years) and the Herbst (17 patients, mean age 11.0 ± 1.4 years) were matched for sex, age, overjet, skeletal class and mandibular divergence. The patients received lateral cephalometric radiographs (LCRs) at the beginning of treatment (T1 ), after treatment (T2 ) and at follow-up (T3 ). In the HGA group, patients underwent LCRs 7 months before the beginning of treatment (T0 ), which were used as growth reference for intra-group comparison. Paired Student's t tests were used for intra- and inter-group comparisons (α = .05). RESULTS: Treatment changes (T2 -T1 ) did not differ significantly between the groups. However, at follow-up (T3 -T1 ) the Herbst group showed a smaller increase than the HGA group in the vertical position of the hyoid bone relative to the Frankfort plane (P = .013) and mandibular plane (P = .013). CONCLUSIONS: There were no significant differences in the upper airway, hyoid bone position and craniofacial morphology between the groups at the end of treatment. However, the Herbst may provide better long-term control of the vertical position of the hyoid bone than the HGA in children with skeletal class II malocclusion.

The influence of mouth breathing on skeletal and dental features of splanchnocranium.

OBJECTIVE: This study was performed to investigate changes in dentofacial characteristics associated with mouth breathing (MB) and adenoidectomy. BACKGROUND: MB is considered to be an etiological factor of malocclusion. Adenoidectomy is supposed to have the ability to prevent the development of dentofacial deformities. METHODS: This retrospective study included 123 patients, namely 57 nose breathers, 19 former mouth breathers, who have undergone adenoidectomy, and 47 mouth breathers. The groups were compared according to their skeletal and dental characteristics. The measurements of each individual were obtained from lateral cephalograms and dental casts. The comparison was done using one-way ANOVA, Bonferroni post-hoc, Mann-Whitney U and Kruskal-Wallis tests. The statistically significant difference was defined as p<0.05. RESULTS: The MB group showed an increase in ArGoMe (p=0.02) angle. No difference was found in the sagittal parameters among the groups. Upper dental arch compression was positively correlated with MB(p=0.00), even in adenoidectomy cases (p=0.01). CONCLUSION: MB alters the vertical and transverse growth of the craniofacial complex. It is associated with longer lower anterior facial height and decreased maxillary intermolar distance. However, it does not influence the sagittal parameters. Airway clearance via adenoidectomy promotes the normalization of vertical parameters (Tab. 1, Fig. 2, Ref. 20).

A multilevel analysis of craniofacial growth in subjects with untreated Class III malocclusion.

OBJECTIVE: To analyse the craniofacial growth of a long-term semi-longitudinal sample of Caucasian subjects with untreated Class III malocclusion. SETTING AND SAMPLE POPULATION: A total of 144 Caucasian subjects (of North American and Italian origin) with untreated Class III malocclusion. MATERIALS AND METHODS: Subjects aged 2 years and 9 months up to 21 years and 7 months were selected. A multilevel model was used to calculate growth curves for ten variables for both each individual subject and for the whole sample. RESULTS: There was a statistically significant increase for total mandibular length (Co-Gn. T2-T1 = 8.4 mm), midfacial length (Co-A. T2-T1 = 3.4 mm) and lower anterior facial height (ANS-Me. T2-T1 = 3.8 mm). The multilevel analysis showed two points of acceleration of growth (about 3-5 years of age and 11-15 years of age) for seven out of ten variables. For Co-Gn and Co-A variables, males presented points of maximum growth delayed by 1 year in comparison with females, with a greater duration (1 year longer) and a greater total growth of about 5 mm. Active mandibular growth continued for a long time after the pubertal spurt: increases in mandibular length ended at about 17 years of age in females and at 21 years and 7 months in males. CONCLUSIONS: Untreated Class III malocclusion showed a specific growth curve, especially for the mandible, whose excesses added up over time. In males, the amounts of mandibular and midfacial growth during the whole observation time were greater and lasted longer than in females.

Vertical growth in mono-and dizygotic twins: A longitudinal cephalometric cohort study.

OBJECTIVE: The aims of this longitudinal analysis of untreated monozygotic and dizygotic twins were to investigate vertical changes of the craniofacial structures during growth, to determine the concordance between genetically twins and to assess the genetic component for the various aspects of vertical growth. SETTINGS AND SAMPLE POPULATION: The sample consisted of 34 pairs of untreated monozygotic twins (23 male, 11 female) and 30 untreated dizygotic siblings of multiple birth (8 male, 8 female and 14 mixed) from the Forsyth Moorrees Twin Study (1959-1975); lateral cephalograms taken from 6 to 18 years of age were analysed at 3-year intervals. MATERIALS AND METHODS: Cephalograms were traced, and longitudinal changes between twins in six angular and proportional vertical cephalometric variables (SN-NL, ML-NL, SN-ML, y-axis, PFH/AFH and LAFH/AFH) were analysed with intraclass correlation coefficients and linear regression modelling. RESULTS: The concordance between monozygotic/dizygotic twins at 18 years of age was moderate to high with intraclass correlation coefficient values between 0.51 and 0.66. Additionally, sex differences in concordance at 18 years of age were found for three variables. High heritability (66%-79%) was observed for 5 of the 6 variables (LAFH/AFH, ML-NL, y-axis, SN-ML, PFH/AFH), while SN-NL showed limited heritability (34%). CONCLUSIONS: Although monozygotic/dizygotic twins share at least part of their genetic material, differences in the vertical dimension were found. This supports the complex developmental mechanism of the human face and the varying influence of genetic and environmental factors.