Lip Prominence Research Articles

Evaluation of the facial profile of skeletal Class III patients undergoing camouflage orthodontic treatment: a retrospective study.

To identify objective metrics for evaluating the esthetics of facial profiles in skeletal Class III patients undergoing camouflage orthodontic treatment. Eighty Asian-Chinese patients classified as skeletal Class III were included. Thirty cephalometric measurements of pre- and posttreatment cephalograms were analyzed. Ten orthodontists assigned visual analog scale (VAS) scores to the pre- and posttreatment profiles based on standardized lateral photographs. Correlations between subjective VAS scores and objective measurements were assessed using Pearson correlation and stepwise multiple linear regression analysis. Lower incisor (L1) protrusion, nasolabial angle, lower lip-E line distance, SNB angle, and L1 to AP plane were significantly correlated with VAS scores of pretreatment profiles of skeletal Class III patients. Factors such as retraction of the lower incisor, increased interincisal angle and overjet, reduction of lower lip-E line distance, as well as augmentation of the Z angle and nasolabial angle were significantly correlated with the changes in VAS scores post-camouflage orthodontic treatment. Stepwise multiple linear regression analysis revealed that pretreatment nasolabial angle, changes in the lower lip-E line distance, and pretreatment Pog-NB distance were the key factors influencing the posttreatment facial profile esthetics of skeletal Class III patients with camouflage orthodontic treatment. Several cephalometric measurements correlate with subjective facial esthetic evaluations of skeletal Class III patients. Changes in lower lip prominence, the pretreatment nasolabial angle, and Pog-NB distance are the main factors related to facial esthetics in skeletal Class III patients after camouflage orthodontic treatment.

Cephalometric Assessment of Differences in Soft Tissue and Dental Compensation in Skeletal Class II Div 1 Malocclusion.

This study was conducted to evaluate the differences in soft tissue as well as dental compensation in skeletal Class II div 1 malocclusion. The study sample consists of pre-treatment lateral cephalograms of 100 subjects of both gender having skeletal Class II and dental Class II div 1 malocclusion visiting the Department of Orthodontics and Dentofacial Orthopaedics, Bharati Vidyapeeth Dental College, and Hospital Navi Mumbai. Cephalograms of the subjects fulfilling the inclusion criteria were included in this study. This research was conducted to assess dental and soft tissue compensation in skeletal Class II div 1 malocclusion and comparative assessment of lip prominence measured from two soft tissue vertical reference lines. The 100 subjects selected randomly out of which 44 men and 56 women, age ranging from 18 to 35 years. ARNETT'S method and PROFFIT'S method showed statistically significant as P < 0.0001. PROFFIT'S method and LEGAN-BURSTONE'S method showed statistically significant as P < 0.0001.

Accuracy in predicting soft tissue changes of orthodontic class III cases using Dolphin® software.

The prediction of posttreatment outcomes is conducive to the final determination of ideal therapeutic options. However, the prediction accuracy in orthodontic class III cases is unclear. Therefore, this study conducted exploration on prediction accuracy in orthodontic class III patients using the Dolphin® software. In this retrospective study, lateral cephalometric radiographs of pre- and posttreatment were collected from 28 angle class III adults who received completed non-orthognathic orthodontic therapy (8 males, 20 females; mean age = 20.89 ± 4.26years). The values of 7 posttreatment parameters were recorded and inserted into the Dolphin® Imaging software to generate a predicted outcome, and then the prediction radiograph and actual posttreatment radiograph were superimposed and compared in terms of soft tissue parameters and landmarks. The prediction showed significant differences with the actual outcomes in nasal prominence (the difference between the prediction and the actual value was - 0.78 ± 1.82mm), the distance from the lower lip to the H line (0.55 ± 1.11mm), and the distance from the lower lip to the E line (0.77 ± 1.62mm) (p < 0.05). Point subnasale (Sn) (an accuracy of 92.86% in the horizontal direction and 100% in the vertical direction in 2mm) and point soft tissue A (ST A) (an accuracy of 92.86% in the horizontal direction and 85.71% in the vertical direction in 2mm) were proven to be the most accurate landmarks, while the predictions in the chin region were relatively inaccurate. Furthermore, the predictions in the vertical direction were of higher accuracy compared to the horizontal direction except for the points around the chin. The Dolphin® software demonstrated acceptable prediction accuracy in midfacial changes in class III patients. However, there were still limitations for changes in the chin and lower lip prominence. Clarifying the accuracy of Dolphin® software in predicting soft tissue changes of orthodontic class III cases will facilitate physician-patient communication and clinical treatment.

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

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

Cephalometric norms in coastal Odisha children

To establish cephalometric norms (skeletal and dental) for Coastal Odisha population of India and to compare it with other Caucasian norms.The Lateral cephalograms of 60 children of 9-16 year age group with normal occlusion and pleasant profile were taken and cephalometric norms were established using Down’s, Steiner’s, Tweeds, Wits, Bjork, Jarabak, McNamara, Ricketts and Schwarz analysis.The study concluded that Overall dimension of cranial base, maxilla and mandible are smaller in Coastal Odia children than that of Caucasians. Odia children are having more proclined upper and lower incisors and smaller upper and lower dental height in anterior and posterior region, steeper mandibular plane angle, greater upper and lower lip prominence but lesser upper lip thickness and strain than Caucasian population.

Bimaxillary protrusion: A literature review

Introduction: Bimaxillary protrusion is an occlusal feature characterized by protrusive and proclined upper and lower incisors, associated with increased flattening of the lips and greater than average degree of lip prominence. It is considered one of the malocclusion types that stimulate patients to seek orthodontic treatment to improve facial symmetry. Objective: To conduct a literature review on bimaxillary protrusion with respect to its aetiological factors, morphological features, prevalence, diagnosis, and management. Methods: Relevant sources of information were searched using electronic databases including Google Scholar, PubMed, Elsevier, ResearchGate, and Web of Science. A total of 28 articles were considered and included in the literature review. Results: It was observed that bimaxillary proclination is prevalent among Asian, African, African-American, and the Caribbean regions, but less prevalent in white Caucasian populations. Treatment of patients with bimaxillary protrusion by extraction of four premolars was found to be successful in decreasing the dental and soft tissue procumbency seen in patients with bimaxillary protrusion. Conclusion: Successful treatment of patients with bimaxillary protrusion starts with a good understanding of the patient’s concerns and sometimes, a close collaboration between an orthodontist and an oral surgeon.

A Cephalometric Evaluation of Soft Tissue Following Maxillary Incisors Retraction

Background: Class 2 Division 1 is the most prevalent type of malocclusion affecting about 32% of Pakistani population. With upper maxillary premolar extraction is one of most frequent treatment choice. Aim: To evaluate the effects of these extractions on soft tissue show variable results depending upon the sex, ethnicity, maxillary arch crowding and pretreatment structure of lips. Methods: In this study pretreatment cephalograms of 106 Class 2 div 1 patients were taken whose treatment plan include extraction of maxillary 1st premolar. Then the second and final cephalograms were taken when retraction of incisors was completed. Mean changes in the position of upper and lower lip were measured with respect to Ricketts E-line before and after completion of retraction of maxillary incisors. Results: After the extraction of premolars there is a significant (P value=0.000) reduction in the lip protrusion of -2.033mm±1.148mm and -1.695mm±1.628mm in both upper and lower lip respectively. Conclusion: Extraction of maxillary premolars cause significant reduction of lip prominence and achieve facial esthetic balance. Keywords: Class 2 div 1, lip position, Premolar Extraction

Interaction Between Subspinale and Two Expansion Protocols in Class III

ABSTRACT Objectives: to assess and compare skeletal,dental and soft tissue changes of three RME protocols using conventional Hyrax, Hybrid Hyrax, and four miniscrew supported Hyrax using alternated expansion and constriction. Methods: 21 patients enrolled in this study with Class III maxillary deficiency, with an average age of 10.5±6 months, and allocated into three groups of seven patients each. Maxillary expansion was done with conventional Hyrax in Group I. Group II: RME with Hybrid Hyrax. Group III: skeletal four-point supported custom-made Hyrax with four palatal micro-implants and alternating rapid maxillary expansion and contraction. A cephalometric tracing of standardized cephalometric x-ray was performed for each patient before and after expansion for various linear and angular measurements and statistically analyzed Results: SNA angle increased significantly (p ≤ 0.05) from pretreatment to post-expansion stage in all groups. There was a statistically significant difference between Groups II and III. When the three Groups were compared, a considerable forward movement of point A was detected in both Group I and Group II. The forward movement of point A, the angle of facial convexity and upper lip prominence improved considerably in GII. Conclusion: Hybrid Hyrax (Group II) showed a significant improvement in forward position of point A concomitant with a significant sagittal skeletal, dental and soft tissue profile improvement.

Orthodontic Assessment of Lip Prominence in Pakistani population

Introduction: Many reference planes are being used to determine prominence of upper and lower lip for orthognathic face profile. E-line and S-line are being used to determine lip position in local popuation of Multan city of Pakistan. Materials and Method: Execution of present study was done in Nishtar Institute of Dentistry, Multan during the period of November 2019-March 2020. 300 (112 Males and 188 Females) subjects were selected for this study from all provinces of Pakistan. Their radiographic records (Lateral cephalograms) were taken from radiographic department of related institution. Acetate matte sheets were used to construct reference planes by using 3H pencil. Steiner’s E-line and Rickett’s S-line were used to find Upper and Lower lip position from these reference lines. SPSS was used to analyze data after applying independent t-test. Result: Mean Upper and lower lip position from E- line was -1.74mm &amp; -0.33mm and from S-line was 0.82mm and 1.47mm Conclusion: Cephalometric lip morphology assessment in Multan, Pakistani adults by using Steiner’s and Rickettsreference planes on lateral cephalogram is slightly different as compare to other populations

Incisor and profile alterations in extraction cases treated with standard Edgewise and pre-adjusted appliances: A controlled before-and-after study

Even though treatment of Class II malocclusion with premolar extractions and incisor retraction might affect incisor inclination and soft tissue profile, the effects of bracket prescription on this have not been thoroughly assessed. Fifty patients (mean age: 13.6 years; 34% male) receiving extraction-based treatment with either standard Edgewise or pre-adjusted appliances were included. Between-group differences in the incisor inclination assessed with lateral cephalograms were analyzed statistically with linear/logistic regression at 5%. Treatment-induced changes included retroclination of the upper/lower incisors (-3.0° and -2.0°, respectively), retraction of the upper/lower incisors (-3.4 mm and -1.5 mm, respectively), retraction of the upper/lower lip (-2.1 mm and -2.0 mm, respectively), and enlargement of the nasolabial angle (+1.6°). Analysis of the data adjusting for confounders indicated that the pre-adjusted group, after treatment, had larger inclination of the upper or lower incisors (+3.2° and +4.5°, respectively), more prominent upper incisors relative to the facial plane (+1.3 mm), and smaller interincisal angle (-7.3 or -7.7°). Post-treatment upper incisor inclination fell within the cephalometric norm significantly more in the pre-adjusted than in the standard Edgewise group (odds ratio 4.3; 95% confidence interval 1.1-16.6). No differences were found in lower incisor prominence, upper/lower lip prominence, or nasolabial angle. Pre-adjusted appliances were associated with increased inclination of the upper and lower incisors, with more prominent upper incisors, and with more acute interincisal angle after retraction compared with standard Edgewise appliances. However, such differences did not translate in greater retraction of the upper/lower lips and greater nasolabial angle.

Profile shape variation and sexual dimorphism amongst middle-aged Northern Europeans.

To explore profile shape variation in a large population of middle-aged individuals and investigate features of sexual dimorphism. Facial profile photographs of 1776 individuals (964 females and 812 males; 46 years old), members of the Northern Finland Birth Cohort 1966 (NFBC1966), were uploaded and digitized with Viewbox software. Profile shape was defined with 47 landmarks (4 fixed and 43 sliding semi-landmarks). Digitized images were reoriented and scaled with Procrustes Superimposition, and shape variation was determined with a Principal Component Analysis. More than 90 per cent of profile shape variation was explained by Principal Components (PC) 1-9. PC1, explaining the largest amount of variation (33.1 per cent) described changes in facial convexity, slope of the forehead, lip, and chin protuberance. PC2 (23.1 per cent variation) was more related to vertical changes of the lower facial third and PC3 (11 per cent variation) primarily described changes in lip protrusion and nasal projection. Shape analysis showed a significant difference between the average female and the average male profile shape (P < 0.001); however, this was not evident upon visual observation. The shape variable most associated with sex was PC3 (η 2 = 0.245; P < 0.001), which described changes in lip prominence and in projection of the dorsal nasal surface. An additional discriminant analysis showed that profile shape predicted sex in 76 per cent of males and 79.6 per cent of females. There is significant sexual dimorphism in facial profile among middle-aged adults. Profile shape variation was associated to changes in lip protrusion, nasal protuberance, and chin projection.

Quantitative investigation of the esthetic impact of lip prominence in relation to the esthetic line

The purpose of this quantitative investigation was to assess the influence of lip prominence in relation to the esthetic line (E-line) on perceived attractiveness and threshold values of desire for treatment. The lip prominence of an idealized silhouette male white profile image was altered incrementally between -16mm to 4mm from the E-line. The images were rated on a Likert scale by pretreatment orthognathic patients (n=75), laypeople (n=75), and clinicians (n=35). In terms of perceived attractiveness, lips to E-line distance within the ranges of -12mm to -16mm and 0-4mm in relation to the E-line was associated with a reduction in median attractiveness scores to below 4 in the patient and clinician groups of observers; for the lay group, the corresponding ranges were -14mm to -16mm and 2-4mm. Relative lip prominence appears to be viewed as more attractive than lip retrusion. Clinicians were generally least likely to suggest treatment for varying levels of bilabial position. For a number of the images, there was reasonable agreement among clinicians and laypeople regarding whether treatment is required. For the clinician group, the only categories for desire for treatment were at a lip to E-line distance within the ranges of -14mm to -16mm and 2-4mm. It is recommended that the range of normal variability of the prominence of the lips and threshold values of the desire for treatment be considered in planning.

Linear correlation between tooth movement and facial profile change in patients with class Ⅱ division 1 malocclusion

Objective: To investigate the correlation between tooth movement and profile change in patients with class Ⅱ division 1 malocclusion. Methods: Pre- and post-treatment lateral cephalograms of 42 patients [10 males and 32 females, (23.8±6.3) years old, mean treatment time: 1.9 years] with class Ⅱ division 1 malocclusion were collected in Department of Oral & Cranio-Maxillofacial Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine from June 2012 to November 2017. The patients were treated with extraction of four first premolars or two maxillary first premolars. Cephalometric analysis was carried out before and after treatment. Thirty parameters were measured. The changes of soft and hard tissue after orthodontic treatment and their correlations were analyzed using bivariate linear regression. Related factors affecting the upper and lower lip, nasolabial angle (NLA) and mentolabial angle (MLA) were analyzed according to the standardized regression coefficient (Beta). Results: Among all the 30 parameters, 18 parameters were statistically different before and after treatment. After treatment, upper central incisor sagittal distance [(63.87±7.14) mm] and upper lip sagittal distance [(77.73±7.60) mm] were significantly decreased (P<0.05). The changes in 14 parameters after treatment showed linear relationship including strong positive correlation between upper lip sagittal retraction and upper central incisor sagittal retraction (r=0.649, P<0.01). There were moderate positive correlations between upper lip and upper central incisor vertical movement (r=0.544, P<0.01). While the sagittal change of gnathion and the Y-axis angle showed moderate negative correlations (r=0.537, P<0.01). The stepwise multiple linear regression showed that the retraction of upper lip process was correlated with the retraction of upper central incisor, the increase of occlusal plane angle and the increase of upper central incisor angle, which was most correlated with the retraction of upper central incisor (Beta=0.79). The downward displacement of upper lip process was correlated with the downward displacement of upper incisor, the decrease of upper central incisor angle, the decrease of the distance between maxillary first molar and palatal plane, and the increase of occlusal plane angle, which was more correlated with the downward displacement of upper incisor and the increase of occlusal plane angle (Beta=0.59). The downward displacement of lower lip process was correlated with the downward displacement of upper incisor and lower incisor, which was more correlated with the upper incisor (Beta=0.36). Conclusions: The relationship among nose, lips and chin was more coordinated. Incisor retraction had significant influence on lip prominence, and the lower lip position was highly related to the movement of upper incisor in sagittal and vertical dimension after orthodontic treatment in patients with class Ⅱ division 1 malocclusion. However, tooth movement had limited impact on the chin position.

Variation in the assessment of facial aesthetics of women during the past 150 years

Variation in the assessment of facial aesthetics through time was investigated with the help of measurements of actresses from 1875 to 2020 most widely considered to be beautiful. Measurements were carried out on reasonably standardised profile and frontal photographs. During the length of the period studied, the following trends in changing attitudes to facial beauty were recognised: a steady increase in the redness and prominence of lips, a decrease in eye height and an increase in eye width, and with it, a decrease in the height/width ratio or the eyes. In addition, the chin-neck angle and the nasolabial angle became sharper. This trend was especially evident after 1950. Both the group of actresses from 1875 to 1900 and a group of British female students from 2005 showed a relatively flatter lip profile, a more prominent chin and a larger nasolabial angle. After 2000 a mild preference developed for somewhat more redness of the upper and lower lips both frontally and from the side, somewhat more prominent lips, sharper nasolabial and chin-neck angles and a narrower eye height.

Intraoperative Optical Coherence Tomography Analysis of Clear Corneal Incision: Effect of the Lateral Stromal Hydration.

Methods The cohort included 65 clear corneal incisions of 49 patients who underwent cataract surgery. Corneal incisions were recorded using a Leica Proveo 8 microscope with an intraoperative OCT EnFocus™ device continuously during the surgery. Corneal incision morphology before and after lateral stromal hydration was analysed. Results Good adaptation of the corneal incision before hydration was present in 39 cases (60%), in 16 cases (24.6%), the prominence of posterior lip was present, and, in 10 cases (15.4%), the posterior lip tongue was inverted/retracted into the incision. In 38 cases (58.5%), hydration had no effect on the incision architecture; most often, it was primarily a well-adapted corneal incision (46.2%), less often an incision with posterior lip prominence (10.8%), or tongue inversion into the incision (1.6%) prior to hydration. Hydration worsened the incision architecture in 14 cases (21.5%); most often, it induced/worsened posterior lip prominence (15.4%), less often posterior lip retraction (1.6%), tongue inversion into the incision (1.6%), gap development in the peripheral part of the corneal incision (1.6%), or incomplete opening of the corneal incision (1.6%). In 13 cases (20%), hydration improved the incision architecture, especially in cases with inverted or retracted posterior lip tongue (12.3%), less often in cases with posterior lip prominence (7.7%). Conclusion Lateral stromal hydration seldom affects the condition of the corneal incision. Still, it can cause both deterioration and improvement of the corneal incision architecture. Intraoperative OCT provides real-time monitoring of corneal incision morphology during hydration procedure.

Comparative evaluation of facial soft tissue characteristics inherited between parents and off springs in families native of Himachal Pradesh-A photographic study

The form and function of the craniofacial complex is determined by a complex interaction between genetic and environmental factors thus influencing facial morphology. Facial photographs taken in a standardized pattern assumes great significance in studying heritability of soft-tissue facial features between parents and their offspring. To evaluate the facial soft-tissue pattern of parents and their offspring with the help of standardized facial photographs and to find the degree of correlation between them. A total sample of 120 children within the age-group of 16-25 years and their parents were selected from ethnic Himachal Pradesh population. Standardized photographs (frontal and right lateral) of entire sample were taken and then traced. Twenty-four parameters involving linear and proportional measurements were measured. Statistically significant correlations between parents and their offspring were found for upper facial height, total facial height, lip length at philtrum, chin projection, upper lip to S line, Nasal prominence, true vertical to tip of nose, true vertical to subnasale, true vertical to pogonion, vertical lip-chin ratio. Stronger heritability was found between daughters to their mothers than to their fathers. Sons showed heritability from both parents for Upper lip prominence to E-line and True vertical to Subnasale. There was strong evidence indicating genetic contribution for both linear and proportional parameters. Highest correlations in inheritance of facial features was found between mother and daughter. Thus, parental data can be used to predict soft tissue facial form of offspring and information from siblings can also be used.

Lip Prominence Using Different Reference Planes

Introduction: Facial beauty lies on lip prominence which in turn is the reflection of dental and skeletal relation of the jaws beside the lip morphology. Thus, orthodontist has control over lip prominence to enhance beauty by altering skeletal and dental relation. Hence analyzing lip prominence is essential for the success of orthodontic treatment. The aim of the present study is to determine lip prominence using different reference planes and secondly to assess sexual differences in lip prominence.&#x0D; Materials &amp; Method: lateral cephalograms of 43 (23 males and 20 females) Brahmins aged 18 - 27 years were collected. They were having dentally: Angle’s Class I molar and canine relation with normal overjet and overbite and skeletally: normal jaw relationship, symmetric face with acceptable facial profile, without craniofacial abnormalities. Linear distance was measured in lateral cephalograms from most prominent point of the lip to reference planes of different analysis system. Comparative test was conducted within Brahmins to check gender diversity at significance level p ≤ 0.05.&#x0D; Result: Comparison of lip prominence of male and female Brahmins were found to have no statistically significant differences except for the upper lip to Burstone B line (p ≤ 0.05) and lower lip to Holdaway H line (p ≤ 0.05). When means of males and females were compared males were found to have more protrusive lips.&#x0D; The Result of this study indicates protrusive lips of Brahmins compared to the established norms of Caucasians as analyzed with reference plane of different analysis system namely Ricketts, Steiners and Burstones. Sushners analysis showed retrusive lips indicating retrusive lips of Brahmins as compared with Black population.&#x0D; Conclusion: During orthodontic treatment planning lip prominence should be emphasized based on gender and ethnicity.

Three-dimensional photographic analysis of the face in European adults from southern Spain with normal occlusion: reference anthropometric measurements

BackgroundRecent non-invasive 3D photography method has been applied to facial analysis, offering numerous advantages in orthodontic. The purpose of this study was to analyze the faces of a sample of healthy European adults from southern Spain with normal occlusion in order to establish reference facial soft tissue anthropometric parameters in this specific geographic-ethnic population, as well as to analyze sexual dimorphism.MethodsA sample of 100 healthy adult volunteers consisting of 50 women (mean age, 22.92 ± 1.56 years) and 50 men (mean age, 22.37 ± 2.12 years) were enrolled in this study. All participants had normal occlusion, skeletal Class I, mesofacial pattern, and healthy body mass index. Three-dimensional photographs of the faces were captured non-invasively using Planmeca ProMax 3D ProFace®. Thirty landmarks related to the face, eyes, nose, and orolabial and chin areas were identified.ResultsMale displayed higher values in all vertical and transversal dimensions, with the exception of the lower lip height. Larger differences between sexes were observed in face, mandible, and nose. Male also had higher values in the angular measurements which referred to the nose. No sex differences were found in transverse upper lip prominence or transverse mandibular prominence. No differences were found in the ratio measurements, with the exception of intercantal width/nasal width, which was higher in women than in men.ConclusionsReference anthropometric measurements of facial soft tissues have been established in European adults from southern Spain with normal occlusion. Significant sexual dimorphism was found, with remarkable differences in size between sexes

Changes of lip morphology following mandibular setback surgery using 3D cone-beam computed tomography images.

BackgroundThe aims of this study are to evaluate the lip morphology and change of lip commissure after mandibular setback surgery (MSS) for class III patients and analyze association between the amount of mandibular setback and change of lip morphology.MethodsThe samples consisted of 14 class III patients treated with MSS using bilateral sagittal split ramus osteotomy. Lateral cephalogram and cone-beam CT were taken before and about 6 months after MSS. Changes in landmarks and variables were measured with 3D software program Ondemand™. Paired and independent t tests were performed for statistical analysis.ResultsLandmarks in the mouth corner (cheilion, Ch) moved backward and downward (p < .005, p < .01). However, cheilion width was not statistically significantly changed. Landmark in labrale superius (Ls) was not altered significantly. Upper lip prominence angle (ChRt-Ls-ChLt °) became acute. Landmarks in stomion (Stm), labrale inferius (Li) moved backward (p < .005, p < .001). Lower lip prominence angle (ChRt-Li-ChLt °) became obtuse (p < .001). Height of the upper and lower lips was not altered significantly. Length of the upper lip vermilion was increased (p =< 0.01), and length of the lower lip vermilion was decreased (p < .05). Lip area on frontal view was not statistically significantly changed, but the upper lip area on lateral view was increased and change of the lower lip area decreased (p > .05, p < .005). On lateral view, upper lip prominent point (UP) moved downward and stomion moved backward and upward and the angle of Ls-UP-Stm (°) was decreased. Lower lip prominent point (LP) moved backward and downward, and the angle of Stm-LP-Li (°) was increased. Li moved backward. Finally, landmarks in the lower incisor tip (L1) moved backward and upward, but stomion moved downward. After surgery, lower incisor tip (L1) was positioned more superiorly than stomion (p < .05). There were significant associations between horizontal soft tissue and corresponding hard tissue. The posterior movement of L1 was related to statistically significantly about backward and downward movement of cheilion.ConclusionsThe lip morphology of patients with dento-skeletal class III malocclusion shows a significant improvement after orthognathic surgery. Three-dimensional lip morphology changes in class III patients after MSS exhibited that cheilion moved backward and downward, upper lip projection angle became acute, lower lip projection angle became obtuse, change of upper lip area on lateral view was increased, change of lower lip area decreased, and morphology of lower lip was protruding. L1 was concerned with the lip tissue change in statistically significant way.

Genetic and Environmental Contributions to Facial Morphological Variation: A 3D Population-Based Twin Study.

IntroductionFacial phenotype is influenced by genes and environment; however, little is known about their relative contributions to normal facial morphology. The aim of this study was to assess the relative genetic and environmental contributions to facial morphological variation using a three-dimensional (3D) population-based approach and the classical twin study design.Materials and Methods3D facial images of 1380 female twins from the TwinsUK Registry database were used. All faces were landmarked, by manually placing 37 landmark points, and Procrustes registered. Three groups of traits were extracted and analysed: 19 principal components (uPC) and 23 principal components (sPC), derived from the unscaled and scaled landmark configurations respectively, and 1275 linear distances measured between 51 landmarks (37 manually identified and 14 automatically calculated). The intraclass correlation coefficients, rMZ and rDZ, broad-sense heritability (h2), common (c2) and unique (e2) environment contributions were calculated for all traits for the monozygotic (MZ) and dizygotic (DZ) twins.ResultsHeritability of 13 uPC and 17 sPC reached statistical significance, with h2 ranging from 38.8% to 78.5% in the former and 30.5% to 84.8% in the latter group. Also, 1222 distances showed evidence of genetic control. Common environment contributed to one PC in both groups and 53 linear distances (4.3%). Unique environment contributed to 17 uPC and 20 sPC and 1245 distances.ConclusionsGenetic factors can explain more than 70% of the phenotypic facial variation in facial size, nose (width, prominence and height), lips prominence and inter-ocular distance. A few traits have shown potential dominant genetic influence: the prominence and height of the nose, the lower lip prominence in relation to the chin and upper lip philtrum length. Environmental contribution to facial variation seems to be the greatest for the mandibular ramus height and horizontal facial asymmetry.