Soft tissue adaptability to hard tissues in facial profiles

Assessment of hard and soft tissue thickness at mandibular symphysis in skeletal Class III patients with different vertical patterns

INTRODUCTION

This study aimed to assess the bony and soft tissue parameters at mandibular symphysis among skeletal Class III patients with different vertical growth patterns, using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

CBCT images of 60 skeletal Class III non-growing patients were evaluated (mean age 24.9 ± 8.4 years). Study samples were classified into three facial types based on the mandibular plane angle (SN-MP angle): low, normal, and high angle. The bony and soft tissue parameters at the mandibular symphysis were evaluated.

RESULTS

Among hard tissue variables, symphysis and pogonion width were significantly narrower in the high-angle group (P < .05). The thickness of the buccal cortex at pogonion was also significantly thinner in subjects with high angles (P < .01). Symphysis height showed an increasing tendency from the low-angle to the high-angle group. However, no significant differences were found in chin width and height according to vertical patterns. Across all soft tissue measurements, the low-angle group exhibited the highest thickness, which gradually decreased in the high-angle group. Statistically significant differences in soft tissue thickness were observed at Menton (Me) and Gnathion (Gn) (P < .05). A significant negative correlation was observed between the SN-MP angle and the thickness of both hard and soft tissues.

CONCLUSIONS

In skeletal Class III subjects, significant differences existed in both hard and soft tissues at the mandibular symphysis, depending on the vertical patterns. These results provide a comprehensive evaluation of symphyseal area, which can aid clinicians in identifying appropriate treatment approaches, especially for combined orthognathic and orthodontic treatment.

Craniofacial identification standards: A review of reliability, reproducibility, and implementation

There are numerous anatomical and anthropometrical standards that can be utilised for craniofacial analysis and identification. These standards originate from a wide variety of sources, such as orthodontic, maxillofacial, surgical, anatomical, anthropological and forensic literature, and numerous media have been employed to collect data from living and deceased subjects. With the development of clinical imaging and the enhanced technology associated with this field, multiple methods of data collection have become accessible, including Computed Tomography, Cone-Beam Computed Tomography, Magnetic Resonance Imaging, Radiographs, Three-dimensional Scanning, Photogrammetry and Ultrasound, alongside the more traditional in vivo methods, such as palpation and direct measurement, and cadaveric human dissection. Practitioners often struggle to identify the most appropriate standards and research results are frequently inconsistent adding to the confusion. This paper aims to clarify how practitioners can choose optimal standards, which standards are the most reliable and when to apply these standards for craniofacial identification. This paper describes the advantages and disadvantages of each mode of data collection and collates published research to review standards across different populations for each facial feature. This paper does not aim to be a practical instruction paper; since this field encompasses a wide range of 2D and 3D approaches (e.g., clay sculpture, sketch, automated, computer-modelling), the implementation of these standards is left to the individual practitioner.

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

OBJECTIVE

The objective of this review is to assess the effect of total maxillary arch distalization (TMAD) treatment on the dental, skeletal, soft tissues, and airways during non-extraction camouflage treatment of class II division 1 patients.

METHODS

We performed a systematic review of the published data in four electronic databases up to April 2023. We considered studies for inclusion if they were examining the effects of TMAD during treatment of class II division 1 malocclusion in the permanent dentition. Study selection, data extraction, risk of bias assessment, and assessment of the strength of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool were performed in duplicate.

RESULTS

Out of the 27 articles that met the initial eligibility criteria, 19 studies were finally selected. Fair to relatively good quality evidence was identified after the risk of bias assessment of the included studies. Out of the 19 selected studies, 5 studies used inter-radicular TADs, 10 studies used modified C- palatal plate (MCPP), 3 studies used infra zygomatic crest (IZC) TADs, 1 study compared buccal TADs versus MCPP, and 1 study compared between cervical headgear and MCPP. The maximum amount of maxillary arch distalization using buccal TADs, MCPP, IZC TADs, and headgear was 4.2mm, 5.4mm, 5mm, and 2.5mm respectively. Different results regarding the amount of dental, skeletal, and soft tissue changes were observed.

CONCLUSIONS

The current low to very low certainty level of evidence suggests that TMAD is effective in camouflaging class II division 1 malocclusion. Future well-conducted and clearly reported randomized controlled trials that include a control group are needed to make robust recommendations regarding the effect of TMAD with different appliances on dental, skeletal, and soft tissue structures.

CLINICAL RELEVANCE

TMAD should be given priority with caution in class II patients who refuse the extraction of premolars. TMAD may be considered an adjunctive approach to solve cases associated with high anchorage need or anchorage loss.

Incisor and Soft Tissue Characteristics of Adult Bimaxillary Protrusion Patients among Different Skeletal Anteroposterior Classifications

The objective of this study was to investigate the upper incisors (U1), lower incisors (L1), and soft tissue profiles of bimaxillary protrusion (BM) adult patients among skeletal Class I (BM1), II (BM2) and III (BM3). Understanding these characteristics would be useful for incisor and lip diagnostics in different skeletal classifications. Fourteen linear and twelve angular variables of the incisors and lips were evaluated in 214 lateral cephalograms (BM1 = 91, BM2 = 84, BM3 = 39). ANOVA and Bonferroni tests compared the measurements. BM1 and BM3 exhibited a greater U1 position and U1 inclination than the norms, while BM2 presented only a greater U1 position than the norms but normal U1 inclination. BM1 and BM3 had a significantly greater U1 position than BM2. BM1 and BM2 demonstrated a greater L1 position and L1 inclination than the norms, whereas BM3 displayed only a greater L1 position than the norms but normal L1 inclination. BM2 had the most anterior L1 position, whereas BM3 had the least anterior position. Only BM2 had a longer anterior dental height (ADH) than the norms, while BM1 and BM3 had a normal ADH and the significantly shortest ADH, respectively. Only BM1 had a normal upper incisor display at rest (U1R), while BM2 and BM3 displayed an increased and decreased U1R, respectively, with significant differences among the three groups. The most significantly protruded upper and lower lips were presented in BM2, but these were exhibited the least in BM3. The most significant acute nasolabial angle (NLA) was found in BM3, whereas BM2 presented the least acute NLA. A normal lip-chin-throat angle (LCTA) was observed in BM1 and BM3, while only BM2 had a greater LCTA than the norms. The most significant obtuse LCTA was found in BM2, while BM3 had the least obtuse LCTA. Therefore, both U1 and L1 in all groups presented protrusion and proclination, except for U1 in BM2, while L1 in BM3 exhibited normal inclination. The ADH and U1R were increased in BM2 but decreased in BM3. The most acute NLA was found in BM3, whereas the least acute was found in BM2. The most obtuse LCTA was in BM2, while the least was in BM3.

Global facial soft tissue thicknesses for craniofacial identification (2023): a review of 140 years of data since Welcker's first study

This year (2023) marks 140 years since the first publication of a facial soft tissue thickness (FSTT) study. Since 1883, a total of 139 studies have been published, collectively tallying > 220,000 tissue thickness measurements of > 19,500 adults. In just the last 5-years, 33 FSTT studies have been conducted. Herein, we add these data (plus an additional 20 studies) to the 2018 T-Table to provide an update of > 81,000 new datapoints to the global tallied facial soft tissue depths table. In contrast to the original 2008 T-Table, some notable changes are as follows: increased FSTTs by 3 mm at infra second molar (ecm2-iM2'), 2.5 mm at gonion (go-go'), 2 mm at mid-ramus (mr-mr'), and 1.5 mm at zygion (zy-zy'). Rolling grand means indicate that stable values have been attained for all nine median FSTT landmarks, while six out of nine bilateral landmarks continue to show ongoing fluctuations, indicating further data collection at these landmarks holds value. When used as point estimators for individuals with known values across 24 landmarks (i.e., C-Table data), the updated grand means produce slightly less estimation error than the 2018 T-Table means (3.5 mm versus 3.6 mm, respectively). Future efforts to produce less noisy datasets (i.e., reduce measurement and sampling errors as much as possible between studies) would be useful.

Hard and soft tissue shape variation and changes in Class II division 1 malocclusion during orthodontic treatment: a geometric morphometric analysis

BACKGROUND

This study aims to determine the hard and soft tissue shape variation and its changes in Class II division 1 malocclusion before and after orthodontic treatment using Geometric Morphometric Analysis.

METHODS

This retrospective study included 141 pre-treatment and near-end treatment lateral cephalometric radiographs of Class II division 1 malocclusion patients aged 16-40 years with a skeletal II pattern (ANB > 4o). 32 landmarks in Cartesian coordinates were created and identified using MorphoJ software to establish a shape analysis.

RESULTS

The vertical dimensions (hypodivergent to hyperdivergent facial profiles) showed the largest variation in the general shape of hard and soft tissue, followed by the anteroposterior dimensions (mild to severe skeletal II patterns). Variations of lip shape (long to short), lip protuberance (everted to inverted), and nasolabial angle (obtuse to acute) were present. Orthodontic treatment affected the shape of the hard and soft tissue significantly (p < 0.0001). T2 showed significant uprighting of upper incisors (17.5o) and lower incisors (3.7o), improved NLA (8o), an increase in upper lip thickness (1.5 mm), and a reduction in lower lip thickness (0.7 mm) (p < 0.05).

CONCLUSION

Vertical and anteroposterior shape variations were found. Orthodontic treatment had an impact on both hard and soft tissue shapes. Hence, understanding both the hard and soft tissue shape variations and the orthodontic treatment changes is crucial for an accurate diagnosis and treatment plan to achieve a successful outcome and excellent patient satisfaction.

Correlation between Nasolabial Angle and Maxillary Incisors Inclination in 18-25-Year-Old Chhattisgarh Population Using Pre- and Post-Treatment Lateral Cephalograms: A Retrospective Study

INTRODUCTION

One of the primary objectives of orthodontic treatment has been the enhancement of facial aesthetics. To obtain the perfect facial profile with aesthetic balance, knowledge of facial anatomy is essential. The diagnosis and treatment planning of orthodontic patients depend greatly on the examination of the soft tissue profile. Since the nasolabial angle is significantly affected by the inclination of the upper incisors, it is a frequently employed soft tissue parameter in orthodontic diagnosis.

AIM

The study aimed to find out the correlation between the nasolabial angles with maxillary incisor inclination.

MATERIALS AND METHODS

In this retrospective study, 120 lateral cephalograms of orthodontic patients including males and females were traced. Their nasolabial angle and maxillary incisor inclination were calculated before and after orthodontic treatment.

RESULT

The mean of pre- and post-treatment nasolabial angle was found to be 91.43° ± 14.008 and 97.93° ± 14.194, respectively. The mean of pre- and post-treatment incisor inclination was found to be 32.59° ± 7.290 and 23.98° ± 6.851, respectively. The gender-wise Pearson's correlation (r) of nasolabial angle with incisor inclination for male and female was found to be -0.464 with a P value of 0.164 and -0.305 with a P value of 0.118, respectively. Overall Pearson's correlation of nasolabial angle with incisor inclination was found to be -0.040 with a P value of 0.384.

CONCLUSION

There is an insignificant negative correlation between nasolabial angle and incisor inclination in the Chhattisgarh population as well as among the two genders.

XGBoost-aided prediction of lip prominence based on hard-tissue measurements and demographic characteristics in an Asian population

INTRODUCTION

Prediction of lip prominence based on hard-tissue measurements could be helpful in orthodontic treatment planning and has been challenging and formidable thus far.

METHODS

A machine learning-based cross-sectional study was conducted on 1549 patients. Hard-tissue measurements and demographic information were used as the input features. Seven popular machine learning algorithms were applied to the datasets to predict upper and lower lip prominence. The algorithm that performed the best was selected for the construction of the prediction model. Evaluation of feature importance was conducted using 3 classical methods.

RESULTS

Among the 7 algorithms, the XGBoost model performed the best in the prediction of the distances between labrale superius or labrale inferius to the esthetics plane (UL-EP and LL-EP distances), with root mean square error values of 1.25, 1.49 and r2 values of 0.755 and 0.683, respectively. Among the 14 input features, the L1-NB distance contributed the most to the prominences of the upper and lower lips. A lip prominence predictor was developed to facilitate clinical application by deploying the prediction model into a downloadable tool kit.

CONCLUSIONS

The XGBoost model performed well with high accuracy and practicability in predicting upper and lower lip prominence. The artificial intelligence-aided predictor could serve as a reference for orthodontic treatment planning.

Development and accuracy of artificial intelligence-generated prediction of facial changes in orthodontic treatment: a scoping review

Artificial intelligence (AI) has been utilized in soft-tissue analysis and prediction in orthodontic treatment planning, although its reliability has not been systematically assessed. This scoping review was conducted to outline the development of AI in terms of predicting soft-tissue changes after orthodontic treatment, as well as to comprehensively evaluate its prediction accuracy. Six electronic databases (PubMed, EBSCOhost, Web of Science, Embase, Cochrane Library, and Scopus) were searched up to March 14, 2023. Clinical studies investigating the performance of AI-based systems in predicting post-orthodontic soft-tissue alterations were included. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and Joanna Briggs Institute (JBI) appraisal checklist for diagnostic test accuracy studies were applied to assess risk of bias, while the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) assessment was conducted to evaluate the certainty of outcomes. After screening 2500 studies, four non-randomized clinical trials were finally included for full-text evaluation. We found a low level of evidence indicating an estimated high overall accuracy of AI-generated prediction, whereas the lower lip and chin seemed to be the least predictable regions. Furthermore, the facial morphology simulated by AI via the fusion of multimodality images was considered to be reasonably true. Since all of the included studies that were not randomized clinical trials (non-RCTs) showed a moderate to high risk of bias, more well-designed clinical trials with sufficient sample size are needed in future work.

Evaluation of Change in the Facial Profile and Aesthetics in Relation to Incisor Position in Both Maxillary and Mandibular Arches

Background The orthodontist is often confronted with the need to predict soft tissue profile changes that may result from the orthodontic treatment. The problem arises because the contribution of many of the factors influencing the soft tissue profile still needs to be fully understood. The complexity of the problem is increased in growing patients in whom the post-treatment soft tissue profile is the result of both growth and orthodontic treatment. A primary motivation for seeking orthodontic treatment is a desire to improve dental and facial aesthetics. To achieve balance in the facial profile treated orthodontically, it is essential to identify the underlying skeletal hard tissue and soft tissue parameters. The present study evaluated the changes in facial profile and aesthetics in relation to incisor position. Materials and methods Samples for this study consisted of pre-treatment lateral cephalograms of the Indian population (n = 450) having different incisor relationships. Subjects aged between 18 and 30 years were included. Angular and linear measurements were taken to analyse the incisor relationship with soft tissue parameters. Results The majority (61.2%) of subjects belonged to the age group of 18-30 years. The overall female-to-male ratio in the study was 7:3. The parameter U1 to L1 was abnormal in 86.8% of subjects. Similarly, the parameters S-line upper lip (UL), S-line lower lip (LL), E-line UL, and E-line LL were found abnormal in 93.9%, 86.8%, 82.6%, and 70.1% of subjects, respectively. A significant agreement was found between U1 to L1 and E-line UL and U1 to L1 and E-line LL. Conclusions The present study concludes that facial aesthetics combines soft and hard tissue corrections, not just based on occlusal relationships but also considering facial harmony. Thus, the incisor relationship is an important asset and strongly correlates with other soft tissue and hard tissue parameters that improve facial aesthetics for the individual undergoing orthodontic treatment.

Anteroposterior relationship of the maxillary central incisors to the forehead in adult Chinese females

Objectives:

The objectives of the study were to evaluate the anteroposterior (AP) relationship of the maxillary central incisors to the forehead in adult Chinese females.

Material and Methods:

The study sample consisted of 100 lateral smiling photographic images of adult Chinese females who were seeking orthodontic treatment (mean age = 24.0 + 6.5 years old). The study sample was compared to a control sample consisting of 100 images of adult Chinese females with harmonious facial profiles downloaded from the internet. The images were resized and rotated to the upright head position in an image editing software. Reference lines were constructed to evaluate forehead inclinations and AP positions of the maxillary central incisors.

Results:

In the control sample, 80% of the maxillary central incisors were positioned between the facial axis point of the forehead (FFA) and the glabella. About 13% were positioned posterior to the FFA point and 7% anterior to the glabella. In the study sample, 31% of the maxillary central incisors were positioned between the FFA point and glabella, 52% posterior to the FFA point, and 18% anterior to the glabella. There was a strong correlation between the position of the maxillary central incisors and forehead inclination in the control sample (r2 = 0.827). The difference in AP maxillary central incisor position relative to the forehead between the two groups was found to be statistically significant (P = 0.000).

Conclusion:

The forehead may be an important landmark when evaluating the AP position of maxillary incisors in adult Chinese female patients.

Relationship of Nasolabial Angle with Maxillary Incisor Proclination and Upper Lip Thickness in North Indian Population

Aim

The aim of the study was to evaluate the relationship between nasolabial angle (NLA) with maxillary incisor proclination (U1-NA) and upper lip thickness (ULT).

Materials and methods

Pretreatment lateral cephalometric radiographs of 120 patients were taken, and NLA, U1-NA, and basic ULT measurements were obtained for each patient. Descriptive statistics were calculated for all the variables involved in the study. The correlation was found using the Pearson correlation coefficient (r) test. p < 0.01 was considered statistically significant.

Results

The mean values of NLA, upper incisor proclination, and ULT were found to be 91.38° ± 7.10°, 34.21° + 5.17°, and 15.38 ± 1.76 mm, respectively. r (r = -0.583) was found between NLA and upper incisor proclination and (r = -0.040) for NLA and ULT.

Conclusion

There is a statistically significant relationship between NLA and U1-NA.

How to cite this article

Garg H, Khundrakpam D, Saini V, et al. Relationship of Nasolabial Angle with Maxillary Incisor Proclination and Upper Lip Thickness in North Indian Population. Int J Clin Pediatr Dent 2022;15(5):489-492.

Soft-Tissue Analysis of Different Sagittal Skeletal Patterns Using the Geometric Morphometric Method

OBJECTIVES

 This study aimed to investigate the size and shape variations of soft-tissue patterns in different sagittal skeletal patterns using the geometric morphometrics method (GMM) obtained from lateral cephalograms.

MATERIALS AND METHODS

 This is a retrospective study, where the sample comprised of 188 Malaysian Malay subjects aged between 18 and 40 years and with different sagittal skeletal patterns. Overall, 71 males and 117 females were gathered for all size and shape analyses. This study incorporated 11 soft-tissue landmarks, which underwent landmark application using tpsDig2 software version 2.31, while the shape analysis was done using MorphoJ software version 1.07a.

STATISTICAL ANALYSIS

 Statistical analyses were performed using IBM SPSS Statistics 26. The result of the analysis of variance (ANOVA) test showed significant differences in some of the parameters between the landmarks. Length D, Length E, Length F, Length H, and Length I showed significant differences (p < 0.05), while other parameters showed no difference (p > 0.05).

RESULTS

 The shape variation of soft-tissue landmarks in different skeletal patterns existed in 18 different dimensions which showed by 18 principal components (PCs). Procrustes ANOVA and canonical variate analysis showed the size and shape differences of soft-tissue patterns between Class II and III and gender groups (p < 0.0001). In discriminant function analysis for Class II subjects, the classification accuracy was 98.4%, whereas subsequent to cross-validation, the classification accuracy was 90.6%. For Class III subjects, the classification accuracy was 96.6%, while after cross-validation, the classification accuracy was 90%.

CONCLUSION

 Different sagittal skeletal patterns demonstrated different soft-tissue shape variations. Class III showed the most protrusive upper and lower lips, while Class II demonstrated the most retrusive lower lip.

Facial Surface Anthropometric Features and Measurements With an Emphasis on Rhinoplasty

BACKGROUND

Facial features and measurements are utilized to analyze patients' faces for various reasons, including surgical planning, scientific communications, patient-surgeon communications, and post-surgery evaluations.

OBJECTIVES

There are numerous descriptions regarding these features and measurements scattered throughout the literature, and the authors did not encounter a current compilation of these parameters in the medical literature.

METHODS

A narrative literature review of the published medical literature for facial measurements used for facial analysis in rhinoplasty was conducted through the electronic databases MEDLINE/PubMed and Google Scholar, along with a citation search.

RESULTS

A total of 61 facial features were identified: 45 points (25 bilateral, 20 unilateral), 5 lines (3 bilateral, 2 unilateral), 8 planes, and 3 areas.A total of 122 measurements were identified: 48 distances (6 bilateral, 42 unilateral), 57 angles (13 bilateral, 44 unilateral), and 17 ratios. Supplemental figures were created to depict all features and measurements utilizing a frontal, lateral, or basal view of the face.

CONCLUSIONS

This paper provides the most comprehensive and current compilation of facial measurements to date. The authors believe this compilation will guide further developments (methodologies and software tools) for analyzing nasal structures and assessing the objective outcomes of facial surgeries, in particular rhinoplasty. Moreover, it will improve communication as a reference for facial measurements of facial surface anthropometry, in particular rhinoplasty.

Comparative assessment of cephalometric with its analogous photographic variables

Objective:

The purpose of this study was to evaluate the accuracy of photographic measurements and compare it with its analogous cephalometric variables.

Materials and Methods:

Lateral cephalograms and standardized facial profile photographs were obtained from a sample of 120 subjects (92 females, 28 males; age 12–22 years with mean age of 17.5 years). A total of 4 linear and 7 angular measurements along with 3 ratios analogous to one another were measured on both. Descriptive statistics for all measurements were computed. Pearson's correlation coefficients were computed between analogous measurements, and regression analysis was done for each variable measured on the photograph to accurately predict the cephalometric variable.

Results:

The reliability of the standardized photographic technique was satisfactory. Most photographic measurements showed highly significant correlations (P < 0.001) with cephalometric variables. Among all measurements used, the A'N'B' angle was the most effective in explaining the variability of its analogous cephalometric (r²= 0.35). The Frankfort-mandibular plane angle' angle showed best results for vertical assessment (r²= 0.81) along with anterior face height (AFH) and lower anterior facial height (r²= 0.859) and ratio lower posterior facial height/AFH (r²= 0.702).

Conclusions:

Although we cannot rule out lateral cephalogram as the primary record in orthodontics, photographic assessment can always be used through proper standardization, as an alternative diagnostic aid, and also for large-scale epidemiological purposes and places with unavailability of cephalostat.

Factors that affect lip changes following incisor retraction in Vietnamese adults with a convex facial profiles

OBJECTIVE:

This study aimed to evaluate the factors that influence lip change through the results of tooth anterior retraction by fixed orthodontic treatment in Vietnamese adult patients with a convex facial profile.

MATERIALS AND METHODS:

This prospective study included 32 Vietnamese adults who have convex facial profiles. Digital software measurements according to Arnett's analysis and the superimposition method were performed to evaluate the changes in dentoskeletal structures, and soft tissue variables included lip change. A multiple logistic regression model was applied with various explanatory variables to analyze the correlation.

RESULTS:

The study revealed a strong correlation of lip change at the site of the cervical point and incisal edge of the upper incisors, and the cervical position demonstrated a stronger correlation. The ratio between lip change and incisor retraction in patients is approximately 1:2.3 at the incisal edge and 1:1.3 at the cervical point.

CONCLUSION:

Lip change was associated with incisor retraction at the cervical and incisal edge, but it did not correlate with the rotation axis of the upper incisors.

Cephalometric predictors for optimal soft tissue profile outcome in adult Asian class I subjects treated via extraction and non-extraction. A retrospective study

OBJECTIVE

The aim of this retrospective study was to identify cephalometric predictors associated with favourable soft tissue profile outcomes after premolars extraction and non-extraction in class I malocclusion subjects.

MATERIALS AND METHODS

A total of 80 subjects, treated with non-extraction and premolars extraction (40 subjects each), were equally divided into favourable (FG) and unfavourable (UFG) groups using subjective and objective soft tissue profile outcome assessment methods. An independent t-test was utilized for the comparison of cephalometric measurements between the non-extraction (NE) and premolars extraction (PME) treatment modalities. Cox proportional hazard algorithm regression analysis was performed to identify cephalometric factors associated with favourable soft tissue outcomes.

RESULTS

The pre-treatment mean age of the NE group was 20.2±2.3 and PME group was 20.2±2.5 years. After dividing the sample of the NE and PME groups according to subjective and objective soft-tissue outcome assessment criteria, FG and UFG consisted of 20 subjects each. Cox proportional hazard algorithm regression analysis found upper incisor to NA angle (95% CI: 1.033, 1.196) to be associated with FG in NE and upper incisor to SN (95% CI: 1.018, 1.206) and ANB angle (95% CI:1.165, 3.608) in PME. There was a statistically significant strong correlation between subjective and objective evaluation methods (P≤0.001).

CONCLUSIONS

Cephalometric analysis is a valuable tool to predict soft-tissue outcomes after NE and PME. Increased upper incisors inclinations at the start of NE treatment result in favourable soft tissue profile outcomes. Slightly convex profile and proclined maxillary incisors are the predictors of favourable soft tissue profile outcome after PME. There was a statistically significant association between subjective and objective evaluation criteria of soft tissue outcomes.

Relationship of anteroposterior position of maxillary central incisors with the forehead in an adult Iranian subpopulation: A cross-sectional study

OBJECTIVE

This study aimed to assess the relationship of the anteroposterior position of maxillary central incisors with the forehead in an Iranian subpopulation residing in Kermanshah city.

MATERIALS AND METHODS

In this cross-sectional study, 12 orthodontists were requested to analyse full-smile profile photographs with complete maxillary incisor and forehead show in 70 patients with optimal facial harmony (35 males and 35 females) as the control group and 140 patients without optimal facial harmony (70 males and 70 females) as the test group. The inclusion criteria were (I) males and females between 18-60 years seeking orthodontic treatment and (II) willingness for participation in the study. The exclusion criteria were (I) presence of severe craniofacial anomalies, and (II) history of orthodontic treatment. The photographs were traced and analysed using Digimizer Image Analysis software 5.3.5. Data were analysed using STATA version 14.2 via independent t-test and linear regression.

RESULTS

A significant difference existed in the anteroposterior position of maxillary incisors in males between the test and control groups (P=0.002). However, this difference was not significant in females of the two groups (P=0.77). A significant difference was noted in the anteroposterior position of maxillary incisors between males and females in the test group (P=0.001) but not in the control group (P=0.80). The frontal angle had a significant correlation with gender and anteroposterior position of maxillary incisors in both groups (P<0.001).

CONCLUSIONS

According to the results, the anteroposterior position of maxillary incisors was significantly different in the test and control groups. The maxillary incisors in males were more retruded than in females. Also, the frontal angle had a significant correlation with the anteroposterior position of maxillary incisors, and by 1° increase in the frontal angle, the incisors were protruded by averagely 0.307mm.

Methods in Genetic Analysis for Evaluation Mandibular Shape and Size Variations in Human Mandible

ABSTRACT

The human mandible has been investigated from both clinical and evolutionary perspectives. Recent advances in genome science have identified the genetic regulation of human mandibular shape and size. Identification of genes that regulate mandibular shape and size would not only enhance our understanding of the mechanisms of mandibular growth and development but also help define a strategy to prevent mandibular dysplasia. This review provides a comprehensive summary of why and how the mandible was evaluated in the human mandible genome study. The variation in human mandibular shape and size has been progressively clarified, not only by focusing on the mandible alone but also by using extremely diverse approaches. The methods of data acquisition for evaluating human mandibular shape and size variation are well established. Furthermore, this review explains how to proceed with future research.

Correlations between objective measurements and subjective evaluations of facial profile after orthodontic treatment

Objective

To investigate the correlations between objective measurements and subjective evaluations of post-treatment facial attractiveness.

Methods

Ten orthodontists rated the subjective visual analog scale (VAS) scores of the facial profiles of 95 patients who had undergone orthodontic treatment. Post-treatment cephalograms and photographs were used. Eleven soft tissue measurements and eight maxillary incisor measurements were constructed and analyzed. Correlations between objective measurements and subjective VAS scores were evaluated using Pearson correlation and quadratic regression analysis.

Results

The VAS scores of different facial proportions were all correlated with the total VAS score. Among soft tissue measurements, the distances from the upper and lower lips to the E line, H angle, forehead inclination, distance from lower lip to the H line, and pogonion-menton angle were negatively correlated with the VAS scores. The Z angle, with a parabolic distribution, was also correlated with the VAS scores. Among maxillary incisor measurements, the distance from the maxillary incisors to the forehead’s anterior limit line and the angulation of the maxillary incisors to the APo line were negatively correlated with the VAS scores.

Conclusions

Several soft tissue and maxillary incisor position measurements were correlated with facial profile evaluation and therefore might be used to evaluate facial attractiveness.

Soft Tissue Changes in Patients With Dentoalveolar Protrusion Treated With Maximum Anchorage: A Systematic Review and Meta-analysis

OBJECTIVE

This meta-analysis aimed at comparing the angular and linear changes of soft tissue profile using conventional anchorage techniques and mini-implant (MI)-based space closure in patients with dentoalveolar protrusion.

MATERIALS AND METHODS

Electronic databases, viz. PubMed, Embase, and Cochrane Central Register of Controlled Trials, were searched for relevant literature from their inception to December 2017 according to the specific inclusion and exclusion criteria. The following Medical Subject Heading terms were used for searching: "skeletal anchorage", "temporary anchorage devices", "miniscrew implant", "mini-implant", "micro-implant". Selected randomized control trials (RCTs) were assessed for their quality using Cochrane's Risk of Bias Tool, whereas the Newcastle-Ottawa scale was used for non-RCTs. Standardized mean difference (SMD) and 95% confidence interval (CI) were obtained with either fixed- or random-effects models based on the heterogeneity of the included studies.

RESULTS

A total of 5 articles (2 RCTs with moderate risk of bias and 3 high-quality non-RCT studies) were included in the final analysis. The nasolabial angle had significantly greater changes in the MI group than in the conventional anchorage group (SMD = 0.68, 95% CI = 0.39 to 0.97, P < .0001). Significantly higher retraction of the upper lip was seen in the MI group than in the conventional group (SMD = -0.51, 95% CI = -0.84 to -0.18; P = .002). No significant difference was seen in the facial convexity (SMD = -0.34, 95% CI = -0.76 to 0.07, P = .106) and lower lip retraction (SMD = 0.28, 95% CI = -1.72 to 2.28, P = .784) between the groups.

CONCLUSION

It was seen that MIs facilitated favorable soft tissue profile than the conventional anchorage devices. However, more high-quality studies are warranted to confirm the clinical effectiveness of MIs.

Facial soft tissue thicknesses in craniofacial identification: Data collection protocols and associated measurement errors

Facial soft tissue thicknesses (FSTT) form a key component of craniofacial identification methods, but as for any data, embedded measurement errors are highly pertinent. These in part dictate the effective resolution of the measurements. As herein reviewed, measurement methods are highly varied in FSTT studies and associated measurement errors have generally not been paid much attention. Less than half (44%) of 95 FSTT studies comment on measurement error and not all of these provide specific quantification. Where informative error measurement protocols are employed (5% of studies), the mean error magnitudes range from 3% to 45% rTEM and are typically in the order of 10-20%. These values demonstrate that FSTT measurement errors are similar in size to (and likely larger than) the magnitudes of many biological effects being chased. As a result, the attribution of small millimeter or submillimeter differences in FSTT to biological variables must be undertaken with caution, especially where they have not been repeated across different studies/samples. To improve the integrity of FSTT studies and the reporting of FSTT measurement errors, we propose the following standard: (1) calculate the technical error of measurement (TEM or rTEM) in any FSTT research work; (2) assess the error embedded in the full data collection procedure; and (3) conduct validation testing of FSTT means proposed for point estimation prior to publication to ensure newly calculated FSTT means provide improvements. In order to facilitate the latter, a freely available R tool TDValidator that uses the C-Table data for validation testing is provided.

Factors affecting changes in soft tissue profile after various treatment modalities for skeletal Class II malocclusion: A cross-sectional study

INTRODUCTION

Various treatment modalities are used to treat skeletal Class II malocclusion with different effects on the soft tissue. This study was aimed to determine factors affecting changes in soft tissue profile after various treatment modalities for skeletal Class II malocclusion.

MATERIALS AND METHODS

A cross-sectional study was conducted using pre-treatment and post-treatment lateral cephalograms of 141 subjects. The sample consisted of 47 patients treated with Clark's Twin Block, 47 with first premolar extractions, and 47 with Class II elastics. The post-treatment cephalograms were superimposed on pre-treatment radiographs using stable landmarks: anterior wall of sella turcica and anterior cranial base. The changes in profile were evaluated by paired t-test using X-Y co-ordinate system. Changes in profile were predicted by using multi-variable linear regression analysis. Level of significance was kept at P≤0.05.

RESULTS

The changes in soft tissue profile were statistically significant for all the landmarks (P<0.001) of nose, upper and lower lip, and chin in horizontal and vertical direction, except subnasale and labrale superius in the horizontal direction. The soft tissue profile changes can be predicted for all landmarks with various prediction powers except pronasale, subnasale, and inferior labial sulcus in the vertical direction.

CONCLUSIONS

Almost all the soft tissue landmarks of nose and lower third of the face exhibit downward and forward movement. The changes in the upper lip in both horizontal and vertical directions were found to be more predictable than those occurring in the lower lip.

Effect of incisor retraction on facial aesthetics

Incisor retraction may result in lip retraction, interlabial gap closure and increase of the nasolabial angle but a clear consensus on the effect of incisor retraction on facial aesthetics has not yet been achieved. Despite current evidence being weak, it seems to indicate that in a well-managed orthodontic case, with or without extractions, the soft-tissue and facial aesthetic changes are generally favourable or clinically insignificant.

Establishment of a prediction method for the mid-facial region of unknown human Mongoloid skeletal remains

Forensic facial approximation is a technique used to estimate the antemortem facial features of unknown skeletal remains. In recent years, many researchers have reported nasal tip predictions with positive results. However, the morphological nasal features of the skull can vary widely, and it is hard to obtain accurate values using facial approximation techniques. We assumed that these variations are due to an over-dependence on the values obtained from a single distance metric factor in an anatomical area. Measurements were acquired using cephalometric radiographic images obtained from 190 Japanese individuals (90 men, aged 18-36 years and 100 women, aged 18-46 years). Soft tissue and skeletal features were traced onto acetate sheets. The orbitale (Or), porion (Po), and the Frankfurt Horizontal Plane (FHP) were plotted in addition to the rhinion (Rhi), anterior nasal spine (ANS), subnasale (Sn), prosthion, and point-A (A). From these, the following were measured: a length from rhinion to prosthion; b length from rhinion to the intersection of a line perpendicular to the anterior nasal spine; c length from the prosthion to the intersection of a line perpendicular to the anterior nasal spine; g the proportion of d/b; and f the proportion of c/b. A calculation was generated from these measurements and from proportions of a-h, and applied to the samples. An R-squared (RSQ) test and standard error (SE) were used to compare the actual and predicted values. The errors observed between the predicted and actual values were not greater than 5mm in any of the samples; 91.3% and 71.2% of predicted Sn had an error lower than 2.5 and 1.5mm respectively, from the actual. Reliable results were obtained using the method in the present study. In addition, in the process of obtaining the measurements, we found reliable proportional differences between the sexes in the piriform and axillary alveolar regions.

Prediction of changes due to mandibular autorotation following miniplate-anchored intrusion of maxillary posterior teeth in open bite cases

Background

Prediction of the treatment outcome of various orthodontic procedures is an essential part of treatment planning. Using skeletal anchorage for intrusion of posterior teeth is a relatively novel procedure for the treatment of anterior open bite in long-faced subjects.

Methods

Data were analyzed from lateral cephalometric radiographs of a cohort of 28 open bite adult subjects treated with intrusion of the maxillary posterior segment with zygomatic miniplate anchorage. Mean ratios and regression equations were calculated for selected variables before and after intrusion.

Results

Relative to molar intrusion, there was approximately 100% vertical change of the hard and soft tissue mention and 80% horizontal change of the hard and soft tissue pogonion. The overbite deepened two folds with 60% increase in overjet. The lower lip moved forward about 80% of the molar intrusion. Hard tissue pogonion and mention showed the strongest correlations with molar intrusion. There was a general agreement between regression equations and mean ratios at 3 mm molar intrusion.

Conclusions

This study attempted to provide the clinician with a tool to predict the changes in key treatment variables following skeletally anchored maxillary molar intrusion and autorotation of the mandible.

Long-term stability of soft tissue changes in anterior open bite adults treated with zygomatic miniplate-anchored maxillary posterior intrusion

OBJECTIVES

To evaluate soft tissue changes and their long-term stability in skeletal anterior open bite adults treated by maxillary posterior teeth intrusion using zygomatic miniplates and premolar extractions.

MATERIALS AND METHODS

Lateral cephalograms of 26 patients were taken at pretreatment (T1), posttreatment (T2), 1 year posttreatment (T3), and 4 years posttreatment (T4).

RESULTS

At the end of treatment, the soft tissue facial height and profile convexity were reduced. The lips increased in length and thickness, with backward movement of the upper lip and forward movement of the lower lip. The total relapse rate ranged from 20.2% to 31.1%. At 4 years posttreatment, 68.9% to 79.8% of the soft tissue treatment effects were stable. The changes in the first year posttreatment accounted for approximately 70% of the total relapse.

CONCLUSIONS

Soft tissue changes following maxillary posterior teeth intrusion with zygomatic miniplates and premolar extractions appear to be stable 4 years after treatment.

The effects of maxillary expansion on the soft tissue facial profile

Purpose

The aims of this retrospective study were to evaluate the possible changes in soft tissue facial profile induced by orthopedic rapid maxillary expansion (RME) and surgically assisted rapid maxillary expansion (SARME), and to correlate them with the underlying hard tissue alterations.

Materials and Methods

16 patients who received bone borne SARME and 25 patients who were subjected to RME using metal cast splint hyrax appliance were analyzed retrospectively. This research was conducted on lateral cephalometric radiographs taken on 2 occasions: before expansion (T1) and at the beginning of any further orthodontic treatment (T2). Investigated lateral cephalometric parameters consisted of Holdaway soft tissue measurements with some supplementary soft tissue, skeletal and dental assessments.

Results

The acquisition of T2 cephalograms which conforms to the initiation of further orthodontic treatment corresponded to 83.25±3.51 days for SARME and 85.68±4.37 days for RME after the expansion was completed. The only significant change in soft tissue profile of the SARME group was a decrease in upper lip thickness (p<0.05), whereas in the RME group, decrease in soft tissue facial profile angle and increase in H angle were found to be statistically significant (p<0.05 for each). For the RME group, the changes in soft tissue facial profile angle and H angle correlated only with the changes in SNB angle (p<0.05).

Conclusion

While bone-borne SARME did not seem to possess the potential to alter soft tissue profile, tooth-borne RME caused a more convex soft tissue profile related to a reduction in SNB.

Subjective facial analysis and its correlation with dental relationships

INTRODUCTION:

Subjective facial analysis is a diagnostic method that provides morphological analysis of the face. Thus, the aim of the present study was to compare the facial and dental diagnoses and investigate their relationship.

METHODS:

This sample consisted of 151 children (7 to 13 years old), without previous orthodontic treatment, analyzed by an orthodontist. Standardized extraoral and intraoral photographs were taken for the subjective facial classification according to Facial Pattern classification and occlusal analyses. It has been researched the occurrence of different Facial Patterns, the relationship between Facial Pattern classification in frontal and profile views, the relationship between Facial Patterns and Angle classification, and between anterior open bite and Long Face Pattern.

RESULTS:

Facial Pattern I was verified in 64.24% of the children, Pattern II in 21.29%, Pattern III in 6.62%, Long Face Pattern in 5.96% and Short Face Pattern in 1.99%. A substantial strength of agreement of approximately 84% between frontal and profile classification of Facial Pattern was observed (Kappa = 0.69). Agreement between the Angle classification and the Facial Pattern was seen in approximately 63% of the cases (Kappa = 0.27). Long Face Pattern did not present more open bite prevalence.

CONCLUSION:

Facial Patterns I and II were the most prevalent in children and the less prevalent was the Short Face Pattern. A significant concordance was observed between profile and frontal subjective facial analysis. There was slight concordance between the Facial Pattern and the sagittal dental relationships. The anterior open bite (AOB) was not significantly prevalent in any Facial Pattern.

Cross-sectional human study of soft tissue chin (STC) thickness in adult patients in relation to sex, facial pattern and skeletal class

PURPOSE

The aim of this study was to study the relations between the soft tissue chin (STC) and sex, skeletal class, and facial pattern; and to describe the shape and behavior of the STC.

METHODS

385 non-growing patients were selected, 206 women and 179 men, with a mean age of 28.8 years (SD 4.2). Patients were divided into groups by skeletal class (class I, II or III) and facial pattern (brachyfacial, mesofacial or dolichofacial). STC thicknesses were measured at pogonion (Pg), soft pogonion (Pg'), gnathion (Gn), soft gnathion (Gn'), menton (Me) and soft menton (Me') in the CBCTs.

RESULTS

Sexual dimorphism was observed at Pg-Pg' and Me-Me'. STC thickness was not related to skeletal class but related to facial pattern. Pg-Pg' and Me-Me' measurements showed significant differences to the combination of skeletal class/facial pattern. STC thickness was not homogenous in terms of shape and behavior.

CONCLUSIONS

The results provide evidence of a strong but complex relationship between sex, facial pattern, skeletal class and STC thickness; for this reason, each patient must be evaluated individually before undergoing orthodontics or orthognathic surgery involving the mandible and the mandibular symphysis.

Factors influencing soft tissue profile changes following orthodontic treatment in patients with Class II Division 1 malocclusion

Background

Several studies have shown soft tissue profile changes after orthodontic treatment in Class II Division 1 patients. However, a few studies have described factors influencing the soft tissue changes. The purpose of this study was to investigate the factors influencing the soft tissue profile changes following orthodontic treatment in Class II Division 1 patients.

Methods

The subjects comprised 104 Thai patients age 8–16 years who presented Class II Division 1 malocclusions and were treated with different orthodontic modalities comprising cervical headgear, Class II traction and extraction of the four first premolars. The profile changes were evaluated from the lateral cephalograms before and after treatment by means of the X-Y coordinate system. Significant soft tissue profile changes were evaluated by paired t test at a 0.05 significance level. The correlations among significant soft tissue changes and independent variables comprising treatment modality, age, sex, pretreatment skeletal, dental and soft tissue morphology were evaluated by stepwise multiple regression analysis at a 0.05 significance level.

Results

The multiple regression analysis indicated that different treatment modalities, age, sex, pretreatment skeletal, dental and soft tissue morphology were related to the profile changes. The predictive power of these variables on the soft tissue profile changes ranged from 9.9 to 40.3 %.

Conclusions

Prediction of the soft tissue profile changes following treatment of Class II Division 1 malocclusion from initial patient morphology, age, sex and types of treatment was complicated and required several variables to explain their variations. Upper lip change in horizontal direction could be found only at the stomion superius and was less predictable than those of the lower lip. Variations in upper lip retraction at the stomion superius were explained by types of treatment (R² = 0.099), whereas protrusion of the lower lip at the labrale inferius was correlated with initial inclination of the lower incisor (L1 to NB), jaw relation (ANB angle), lower lip thickness and sex (R² = 0.403). Prediction of chin protrusion at the soft tissue pogonion was also low predictable (R² = 0.190) depending upon sex, age and initial mandibular plane angle (SN-GoGn). Additionally, age and sex also had mainly effect on change of the soft tissue profile in the vertical direction.

Prediction of lip response to orthodontic treatment using a multivariable regression model

BACKGROUND

This was a retrospective cephalometric study to develop a more precise estimation of soft tissue changes related to underlying tooth movment than simple relatioship betweenhard and soft tissues.

MATERIALS AND METHODS

The lateral cephalograms of 61 adult patients undergoing orthodontic treatment (31 = premolar extraction, 31 = nonextraction) were obtained, scanned and digitized before and immediately after the end of treatment. Hard and soft tissues, angular and linear measures were calculated by Viewbox 4.0 software. The changes of the values were analyzed using paired t-test. The accuracy of predictions of soft tissue changes were compared with two methods: (1) Use of ratios of the means of soft tissue to hard tissue changes (Viewbox 4.0 Software), (2) use of stepwise multivariable regression analysis to create prediction equations for soft tissue changes at superior labial sulcus, labrale superius, stomion superius, inferior labial sulcus, labrale inferius, stomion inferius (all on a horizontal plane).

RESULTS

Stepwise multiple regressions to predict lip movements showed strong relations for the upper lip (adjusted R (2) = 0.92) and the lower lip (adjusted R (2) = 0.91) in the extraction group. Regression analysis showed slightly weaker relations in the nonextraction group.

CONCLUSION

Within the limitation of this study, multiple regression technique was slightly more accurate than the ratio of mean prediction (Viewbox4.0 software) and appears to be useful in the prediction of soft tissue changes. As the variability of the predicted individual outcome seems to be relatively high, caution should be taken in predicting hard and soft tissue positional changes.

Pleasantness of facial profile and its correlation with soft tissue cephalometric parameters: Perception of orthodontists and lay people

Objective:

This study was aimed to evaluate the perception of orthodontists and of lay people about the facial profile and its possible correlation with cephalometrics parameters.

Materials and Methods:

A total of 20 evaluators were divided into two groups (10 orthodontists and 10 people with no relation to such area – lay people). They were asked to evaluate the photographs of 25 young males and of 25 young females, aged 17–24-year-old (mean age of 22.3 years, standard deviation 2.41 years). Photographs were randomly arranged in a photo album. The evaluators rated each photograph by means of a scale ranging from “good” to “deficient” based on the pleasantness of their facial profile. Nasolabial angle, Holdaway's H-line and the distance from H-line to nose tip were measured, in order to verify a possible relation between these soft tissue profile cephalometric measurements and the subjective ratings.

Results:

The kappa statistics test showed a concordance of 0.23 among orthodontists and 0.24 among lay people. Regarding the perception of orthodontists and lay people on facial profile, no significant divergence could be detected. For the correlation between cephalometric parameters and subjective ratings, there was a statistically significant correlation between the measures H and H-nose and the rating ascribed to the profile.

Conclusions:

It was concluded that smaller the difference from the normal cephalometric pattern, the higher was the rating given to the profile, demonstrating an important relation between subjective and objective criteria.

Extraction vs no treatment: Long-term facial profile changes

INTRODUCTION

Long-term soft tissue response to extraction orthodontic treatment has been a subject of interest for years. The purposes of this study were to investigate long-term soft tissue profile changes in an extraction sample and to compare them with profile changes in an untreated sample.

METHODS

A premolar extraction-treated sample (n = 47) and an untreated control sample (n = 57) were studied. Descriptive statistics were collected, and individual t tests were used for comparison and contrast of the treated and untreated samples.

RESULTS

We found that the untreated soft tissue profile changed in the downward and forward direction. The treated soft tissue profile change was similar, but with more of a forward component than in the untreated sample. Most noteworthy was the finding that the soft tissue profiles of both the untreated and the treated samples were similar at the end point.

CONCLUSIONS

The following conclusions were derived from the study. (1) There was no substantive difference in the soft tissue profiles of the samples, but there were some differences in the directional changes between them. (2) The changes for the untreated sample were the greatest for the lips and the chin, with the change occurring in the downward and forward direction. (3) The soft tissue profiles of the extraction sample also had the greatest measurable changes in the lips and the chin, but the changes had more of a forward component than they did in the untreated sample. (4) Extraction treatment does not adversely impact soft tissue profile changes over time.

Association between changes in soft and hard tissue after early chin cup treatment

OBJECTIVE

To assess the soft tissue and to determine the potential association between changes in soft and hard tissue after early chin cup treatment in prognathic children.

MATERIALS AND METHODS

A total of 42 children (21 boys, 21 girls) with skeletal Class III malocclusion due to mandibular prognathism were examined before (mean age, 8.5 ± 0.5 years) and after (mean age, 11.4 ± 0.6 years) chin cup treatment. Data were compared with 25 untreated matched controls (12 boys, 13 girls) with mean ages of 8.5 ± 0.5 years at the first and 11.7 ± 0.5 years at the second observation. Lateral cephalograms were taken before and after 36 months of treatment/observation. We evaluated the changes in hard and soft tissue and the correlations between these changes in both groups.

RESULTS

The skeletal and soft-tissue facial profiles improved significantly in the treated patients, mainly due to changes in the mandible. The chin cup group revealed significant reductions in the facial-convexity angle and lower-lip inclination, leading to a remarkable improvement in the soft-tissue facial profile. We noted similar correlations between changes in the hard and soft tissue in both groups, except for a significant correlation between a pogonion retrusion and reduction in the facial-convexity angle detected only in the chin cup group. Various correlations were observed between corresponding soft and dentoalveolar changes between groups.

CONCLUSION

Soft-tissue changes accompanied the underlying skeletal and dentoalveolar tissue changes after chin cup treatment.

Hard and soft tissue correlations in facial profiles: a canonical correlation study

Background

The purpose of this study was to analyze the relationship between facial hard and soft tissues in normal Saudi individuals by studying the canonical correlation between specific hard tissue landmarks and their corresponding soft tissue landmarks.

Methods

A retrospective, cross-sectional study was designed, with a sample size of 60 Saudi adults (30 males and 30 females) who had a class I skeletal and dental relationship and normal occlusion. Lateral cephalometric radiographs of the study sample were investigated using a series of 29 linear and angular measurements of hard and soft tissue features. The measurements were calculated electronically using Dolphin^® software, and the data were analyzed using canonical correlation.

Results

Eighty-four percent of the variation in the soft tissue was explained by the variation in hard tissue.

Conclusion

The position of the upper and lower incisors and inclination of the lower incisors influence upper lip length and lower lip position. The inclination of the upper incisors is associated with lower lip length.

Accuracies of facial soft tissue depth means for estimating ground truth skin surfaces in forensic craniofacial identification

Facial soft tissue thickness means have long been used as a proxy to estimate the soft tissue envelope, over the skull, in craniofacial identification. However, estimation errors of these statistics are not well understood, making casework selection of the best performing estimation models impossible and overarching method accuracies controversial. To redress this situation, residuals between predicted and ground truth values were calculated in two experiments: (1) for 27 suites of means drawn from 10 recently published studies, all examining the same 10 landmarks (N ≥ 3051), and tested against six independent raw datasets of contemporary living adults (N = 797); and (2) pairwise tests of the above six, and five other, raw datasets (N = 1063). In total, 380 out-of-sample tests of 416 arithmetic means were conducted across 11 independent samples. Experiment 1 produced an overarching mean absolute percentage error (MAE) of 29% and a standard error of the estimate (S(est)) of 2.7 mm. Experiment 2 yielded MAE of 32% and S(est) of 2.8 mm. In any instance, MAE was always ≥20% of the ground truth value. The overarching 95% limits of the error, for contemporary samples, was large (11.4 mm). CT-derived means from South Korean males and Black South African females routinely performed well across the test samples and produced the smallest errors of any tests (but did so for Black American male reference samples). Sample-specific statistics thereby performed poorly despite discipline esteem. These results—and the practice of publishing means without prior model validation—demand major reforms in the field.

Correlation between objective and subjective evaluation of profile in bimaxillary protrusion patients after orthodontic treatment

OBJECTIVE

To correlate the objective cephalometric measurements with subjective facial esthetics in patients with bimaxillary protrusion.

MATERIALS AND METHODS

The sample consisted of 60 Asian-Chinese patients with bimaxillary protrusion who met the inclusion criteria. The facial esthetics of posttreatment profile and the change of profile on standardized lateral photographs were rated by a panel of 10 orthodontists and a panel of 10 lay persons with bimaxillary protrusion. All of the pretreatment and posttreatment cephalograms were digitized and traced. Twenty-five cephalometric measurements were constructed and analyzed. Correlations between the subjective facial esthetic scores and each cephalometric measurement were evaluated.

RESULTS

The cephalometric measurements correlated with the facial esthetic scores of posttreatment profile given by the orthodontist and the lay persons were basically the same. For the evaluation of posttreatment profile in bimaxillary protrusion patients, the upper and lower lip to E-line, upper and lower incisor tip to AP plane, Pg-NB distance, mentolabial angle, and sulcus depth correlated significantly with the esthetic score. For the evaluation of profile change during orthodontic treatment, retraction of upper incisor relative to AP plane or the perpendicular line through sella (line Y), change of upper incisor inclination, change of mentolabial sulcus depth, and retraction of lips relative to E-line were correlated positively with the esthetic value.

CONCLUSIONS

Cephalometric measurements of lip position, incisor position, and chin morphology were key parameters correlated to facial esthetics.