Facial soft tissue harmony and growth in orthodontic treatment

Effect of Biomechanical Properties of Perioral Soft Tissues on Lip Response to Simulated Protraction of Upper Front Teeth

BACKGROUND

Proclination of front teeth in orthodontics and oral rehabilitation may influence lip protrusion and the overall facial profile. We hypothesized that the degree of profile changes is determined by the biomechanical properties of the lips.

OBJECTIVES

(1) to investigate the upper lip changes induced by a simulated protraction of upper front teeth; and (2) to assess the relationship between biomechanical properties of the lips and their response to tooth protraction.

MATERIALS AND METHODS

Thirty-four participants were recruited at the Faculty of Dentistry, University of Otago, New Zealand. Simulated protraction of upper front teeth was achieved by placing a customised stent covering the buccal surface of the maxillary upper incisors and canines, along with the corresponding buccal mucosa and gingiva. Stereophotogrammetry was used to assess lip changes in three dimensions. Biomechanical properties of the lips, including muscle tone, stiffness and elasticity, were measured using a non-invasive digital palpation device.

RESULTS

During the simulated protraction of upper front teeth, the upper lip advanced approximately 50% of the stent thickness, with a considerable inter-individual variation in lip displacement. Soft tissue responses were correlated with the biomechanical properties of the lips with significant correlation coefficients ranging from 0.38 to 0.40. Higher lip tone was associated with increased lip displacement, while greater lip elasticity resulted in reduced lip displacement. Multivariate analyses indicated that upper lip displacement was associated with biomechanical properties and ethnicity, but not with age, sex and body mass index.

CONCLUSIONS

The response of the lips to protraction of front teeth varies largely between individuals and can be partly explained by variations in the biomechanical properties of perioral muscles.

Which of the nine facial profiles according to AM Schwarz is the most (un)attractive?

OBJECTIVE

The human profile has always been fascinating to artists, scientists, and physicians. In the mid 20th century, AM Schwarz created a profile analysis for orthodontics, which categorizes both the sagittal position of the midface as well as the position of the chin, and is still widely used today. In combination, this analysis leads to nine different profile types, which are assumed to differ in terms of their attractiveness. Since there has been hardly any scientific research in this area so far, the aim of this study was to quantify the attractiveness of the nine profile types according to AM Schwarz.

METHODS

The "Basel face model" is a three-dimensional (3D) facial dataset that was created artificially by morphing a total of 100 female and 100 male 3D face scans. For the present study, this face model was modified to ideally represent all nine profile types according to AM Schwarz. The representation of those nine facial models depicted in a standardized lateral perspective were assessed in terms of attractiveness by 1261 volunteers of different ages and educational level. The ratings were statistically analyzed using repeated measures analysis of variance (ANOVA) and pairwise comparisons.

RESULTS

The results revealed significant differences in attractiveness regarding the nine profile types. Average faces were perceived significantly more attractive than antefaces and these in turn were perceived more attractive than retrofaces. Furthermore, straight and backward-slanting profiles were rated significantly more attractive than forward-slanting profiles. There were no clinically relevant differences between the assessments of males and females or between raters of different educational levels.

CONCLUSION

The perceived attractiveness of the nine profile types according to AM Schwarz differed significantly. This perception did not seem to be affected by gender or the level of education.

Treatment of an adult patient with severe dental crowding by applying asymmetric extraction, fixed appliance, and micro-implant anchorage: a case report

BACKGROUND

Severe dental crowding and protrusion often necessitate symmetric extraction for correction. However, asymmetric extraction may serve as a viable, albeit challenging, treatment option when the prognosis of individual tooth is poor. In this report, we present a case where asymmetric extraction was employed to address severe dental crowding and deviated midlines, resulting in satisfactory outcomes following retention.

CASE PRESENTATION

We report a case of a 31-year-old woman with severe dental crowding and deviated dental midlines. A fixed appliance, micro-implant anchorage, and asymmetric extraction, including a mandibular canine with severe buccal malposition, were applied to the patient. The treatment outcomes demonstrated successful achievement of the treatment objectives, with well-aligned teeth exhibiting solid interdigitation and the dental midlines aligned with the facial midline. At the 21-month follow-up, midline stability, favorable occlusal interdigitation, and improved smile line were observed.

CONCLUSIONS

Asymmetric extraction may be considered a viable approach for patients with individual tooth of poor prognosis. Treatment stability can be achieved through well-interdigitated occlusion and the use of various retention methods.

Implications of Lingual Orthodontics Compared to Conventional Orthodontics

In orthodontics, the treatment plan and the impact of orthodontic appliances on patients' aesthetic appearance have significantly influenced patients' aesthetic demands over time. Patients considering orthodontic treatment are very concerned about the potential compromise in facial appearance that conventional orthodontic treatment could cause. Lingual orthodontics offers an aesthetically pleasing appearance compared to conventional orthodontic systems, addressing the growing demand for inconspicuous treatment options. This review examines the implications of lingual orthodontics compared to conventional orthodontics, focusing on aesthetics, oral health outcomes, and patient satisfaction. The benefit of lingual brackets is that when positioned on the teeth's lingual surfaces, they are almost undetectable. However, they are associated with increased difficulty in oral hygiene maintenance due to their placement, leading to higher plaque accumulation that causes compromised periodontal health. Conversely, studies show a lower incidence of white spot lesions on lingual surfaces compared to buccal surfaces, suggesting a reduced risk of caries. Challenges with lingual systems include increased tongue discomfort and speech difficulties. Despite these challenges, lingual orthodontics demonstrates favourable outcomes for patients prioritising aesthetics. Future advancements should focus on improving appliance designs to enhance patient comfort and oral hygiene accessibility, ensuring optimal treatment outcomes. Interdisciplinary collaboration and comprehensive oral hygiene education are essential to maximise the benefits of lingual orthodontics.

Distraction Osteotomy Combined With Orthodontics: An Effective Way to Decrease Short-term Recurrence in Treating Child Craniofacial Microsomia

BACKGROUND

This study aims to investigate strategies for reducing early relapse following mandibular distraction osteotomy (MDO) in craniofacial microsomia (CFM) patients.

METHODS

Forty CFM patients were divided into 2 groups: 20 underwent MDO alone, while 20 received MDO combined with orthodontic treatment (MDO-O). Preoperative, prefixation, and postfixation CT data in DICOM format were collected and reconstructed using Proplan software. Spatial geometric analysis was conducted to assess the inclination angle of the occlusal plane (OP), and OP deviation was directly measured using the software.

RESULTS

Patients in the MDO-O group demonstrated a statistically significant improvement in OP inclination at the end of the fixation period compared with those who underwent MDO alone ( P =0.003).

CONCLUSIONS

Combining MDO with a bite plate and bite glue sticks in CFM patients during the mixed dentition period enhances OP outcomes, effectively reducing short-term recurrence.

Radiographic Imaging for the Diagnosis and Treatment of Patients with Skeletal Class III Malocclusion

Skeletal Class III malocclusion is one type of dentofacial deformity that significantly affects patients' facial aesthetics and oral health. The orthodontic treatment of skeletal Class III malocclusion presents challenges due to uncertainties surrounding mandibular growth patterns and treatment outcomes. In recent years, disease-specific radiographic features have garnered interest from researchers in various fields including orthodontics, for their exceptional performance in enhancing diagnostic precision and treatment effect predictability. The aim of this narrative review is to provide an overview of the valuable radiographic features in the diagnosis and management of skeletal Class III malocclusion. Based on the existing literature, a series of analyses on lateral cephalograms have been concluded to identify the significant variables related to facial type classification, growth prediction, and decision-making for tooth extractions and orthognathic surgery in patients with skeletal Class III malocclusion. Furthermore, we summarize the parameters regarding the inter-maxillary relationship, as well as different anatomical structures including the maxilla, mandible, craniofacial base, and soft tissues from conventional and machine learning statistical models. Several distinct radiographic features for Class III malocclusion have also been preliminarily observed using cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI).

The reliability of analytical reference lines for determining esthetically pleasing lip position: An assessment of consistency, sensitivity, and specificity

INTRODUCTION

This study aimed to identify a simple yet reliable soft-tissue parameter for the clinical determination of esthetic lip position by investigating the most consistent reference lines and assessing their sensitivity and specificity.

METHODS

A total of 5745 records from Chinese patients aged >18 years were screened. In part I of the study, lateral view photographs of 96 subjects (33 males, 63 females) with esthetic facial profiles were selected. The profile esthetics of each photograph was first scored by 52 dental students, followed by 97 laypeople on a 5-point attractiveness scale. For the top 25% of photographs with the highest score for each sex (8 males, 16 females), the consistency of 6 commonly used reference lines were assessed to determine the esthetic lip position. In part II of the study, lip positions relative to Steiner's (S) and Ricketts' (E) lines in the profile photographs of 86 patients (43 males, 43 females) deemed to have an esthetically unpleasing profile were compared with those in 86 Chinese movie star idols (43 males, 43 females).

RESULTS

In part I of the study, the S, E, and Burstone's (B) lines exhibited the lowest standard deviations for the upper and lower lips. B line was excluded from further analysis because of its higher mean absolute values, and S and E lines were used for the subjective assessment in part II of the study. In part II, the S line showed a sensitivity of 86.0% and 86.0% and a specificity of 81.4% and 83.7% for males and females, respectively. In contrast, the E line presented a sensitivity of 88.4% and 93.0% and a specificity of 79.1% and 74.4% for males and females, respectively.

CONCLUSIONS

S, E, and B lines were the most consistent soft-tissue parameters among both sexes; however, because of the smaller absolute values, the S line would be more convenient among the 3 for a quick clinical assessment of lip position. Moreover, the performance of both S and E lines was similar among both sexes, which supports using these lines in assessing the esthetic lip position.

Comparing the esthetic impact of virtual mandibular advancement, bichectomy, jawline, and their combination

INTRODUCTION

The purpose of this study was to compare the effects of mandibular advancement (MA), bichectomy, jawline, and their combination on facial attractiveness. The 3-dimensional (3D) visual sculpting is a method to perform the task.

METHODS

FaceBuilder software, a Blender 2.93 LTS add-on, was used to generate a 3D head and face model of a female patient with Class II Division I malocclusion. MA, bichectomy, jawline, and combination modifications were performed on the model using a 3D virtual sculpting tab, and 4 new head models were created. Five hundred thirteen participants scored lateral and frontal views of the modified and reference models. The Mann-Whitney U, Kruskal-Wallis, and Wilcoxon tests were used for statistical analysis.

RESULTS

MA modification received the highest frontal and lateral image scores. The raters found the jawline frontal photograph to be the least attractive. Significant differences were observed between the lateral and frontal attractiveness scores in all modifications except bichectomy. The combination of 3 modifications in both frontal and lateral images received the second-lowest score.

CONCLUSIONS

Facial esthetic modifications receive different attractiveness scores in lateral or frontal evaluations. MA outperforms bichectomy and jawline augmentation in terms of improving facial attractiveness.

Balance and thickness of soft tissue of the lower third of the face in different vertical patterns of growth

Introduction/Objective. Variations in thickness of soft tissues can influence the position of facial structures as well as facial aesthetics. The objective of the study was to determine whether the frequency of soft tissues imbalance depends on the vertical growth pattern of the face. Methods. The present study consisted of 90 pretreatment lateral cephalograms of adult Serbian Caucasian orthodontic patients (30 male and 60 female), between 18?27 years of age, average 23.6 years. Only the patients with the skeletal class I, based on the values of A-Nasion-point B angle and Wits appraisal, were chosen for the study. All patients were divided into three groups of 30 patients, those with hyperdivergent, hypodivergent and normal vertical growth patterns based on the values of Frankfort mandibular plane angle. Soft tissue of each patient was evaluated following the method given by Merrifield. Results. The obtained results showed that soft tissues of the chin and upper lip were thickest in hypodivergent and thinnest in patients with hyperdivergent growth type. The largest number of patients with soft tissue imbalance was observed in the normal and hyperdivergent vertical growth pattern groups, eight out of 30 patients. The number of patients with imbalance greater than 3 mm was largest in the group with hyperdivergent growth pattern. Conclusion. The pathological skeletal pattern of growth combined with the common occurrence of soft tissue imbalance makes orthodontic treatment in hyperdivergent group of patients more difficult in comparison to patients with normal or hypodivergent growth pattern.

Determination of craniofacial and dental characteristics of individuals with Williams-Beuren syndrome by using 3D facial scans and radiographs

BACKGROUND

Williams-Beuren syndrome (WBS) is caused by a microdeletion on chromosome 7q11-23 and clusters a variety of systemic affectations.

AIM

To investigate whether 3D facial scans can detect WBS by objectively addressing their craniofacial, skeletal and dental characteristics, compared with those of a non-affected control group.

MATERIALS AND METHODS

3D facial surface scans of 17 WBS individuals and 33 normal developing patients were analysed. Additionally, cephalometric and panoramic radiographs of subjects with WBS were compared with those of non-affected individuals.

RESULTS

The 3D surface scans showed significant facial differences around the nose and mouth area. The cephalometric aspects of individuals with WBS differed mainly at the lower incisor region. Additionally, hypoplastic tooth morphology seems to be more often present in WBS.

CONCLUSION

3D images are a non-invasive, efficient method to observe facial anomalies and facilitate an early diagnosis of WBS. Additionally, the analysis of the cephalometric and panoramic images revealed significant differences in dental characteristics. Together with early diagnosis through 3D images, these can help in the establishment of adequate medical, dental and orthodontic treatment planning.

Facial soft tissue depth measurements in cone-beam computed tomography: A study of a Brazilian sample

Forensic facial reconstruction (approximation) (FFR) is an aid to human identification when no presumed identity is available. It is based on average soft tissue thickness (STT) applied onto a skull. These averages vary at each landmark according to sex, ancestry, and Facial Growth Patterns (FGP). To obtain the reference, there are different protocols and conditions, such as needles in cadavers, ultrasound, magnetic resonance, and computer tomography. Using cone-beam computed tomography (CBCT), landmark placement and direction of measurement are critical. The purpose of this article is to detailly describe a method for STT measurement in CBCT DICOM files and to test it in the analysis of a multi-ancestral Brazilian sample, subdivided into sex, age and FGP. A sample of 100 (50 male and 50 female) CBCT exams were selected and the volume was primarily been repositioned to cephalometric standards. A detailed description of the location and measurement direction of 32 landmarks was provided and granted good reproducibility of the measurements. The averages were assessed by sex, age, and FGP. There were significant differences between males and females. The CBCT measuring protocol provided standardization of measurements and is a method to be used in future researches. Advantages of CBCT, such as the subject's upright position and adjustable volume positioning, also justify its usage. Limited differences of STT were related to age and FGP. The updated Brazilian soft tissue thickness chart is a reliable source of data for forensic and clinical purposes.

A Communication Guide for Orthodontic-Restorative Collaborations: An Orthodontic Perspective on the Importance of Working in a Team

As both restorative dentists and specialists have their respective realms of expertise, it is important to develop a team of qualified providers to improve treatment outcomes for patients. In many cases, this involves collaboration between a restorative dentist and orthodontist. Effective communication is critical, with the dentist's understanding of basic orthodontic terminology and case planning considerations. Recognizing the context in which to apply normative occlusal and cephalometric values often necessitates comprehensive specialty-level experience. All providers should recognize when to involve the indicated team members when complex multidisciplinary treatment needs are present. The team approach offers an opportunity to optimize excellent patient care.

Evaluation of the relationship between malar projection and lower facial convexity in terms of perceived attractiveness in 3-dimensional reconstructed images

Background

This study aimed to investigate dental student’s perception of facial attractiveness with regard to different combinations of anteroposterior malar-jaw positions using 3-dimensional (3-D) reconstructed images of subjects.

Methods

Two Chinese young adults (1 male and 1 female) with straight profiles and average malar projections were selected for the study. 3-D facial images and cone-beam computed tomography images of these two subjects were superimposed using 3-D imaging software. Lateral and oblique views of nine different images were created by moving the maxillomandibular complex and/or zygomatic bone by 4 mm either forward or backward along the sagittal plane. One hundred three undergraduate dental students (n = 24, 33, and 46 students from the Year 3, 4, and 5, respectively) then scored lateral and 45° oblique view images of the newly reconstructed faces.

Results

In the present study, images with a neutral malar and retruded jaws were found to be the most attractive in both male and female subjects. In addition, the Protruded malar (PM) group (p < 0.001), and the Retruded Jaws (RJ) group were rated more attractive (p < 0.001). Furthermore, the Relatively Prominent malar (RP) group was rated more attractive (p < 0.001) when malar-jaw relative positions were compared.

Conclusion

This study shows that a neutral or a protruded malar favours facial attractiveness in both Chinese male and female subjects. Therefore, an appropriate relationship between malar projection and lower facial convexity should be taken into consideration while designing the orthodontic/orthognathic treatment plans for enhanced aesthetic outcomes.

Influence of orthodontic appliance design on employment hiring preferences

INTRODUCTION

The objective of this study was to evaluate the extent to which different types of orthodontic appliances influence the hiring process of an individual applying for a customer service position.

METHODS

A total of 7 images were created for 2 adult models: 1 male and 1 female. One image was produced without orthodontic appliances, and 6 simulated the use of orthodontic appliances, including a conventional metallic appliance with a gray elastic ligature, a conventional metallic appliance with blue elastic ligature, a conventional appliance with a transparent elastic ligature, a self-ligating metal appliance, a self-ligating esthetic appliance, and a clear aligner. A photo album was designed for each model and delivered, along with a questionnaire, to individuals in charge of job interviews and hiring. These evaluators included 236 individuals, divided into 4 groups according to age and gender: males between 18-35 years (M), males over 35 years (M > 35), females between 18-35 years (F), and females over 35 years (F > 35). The evaluators quantified the chance of hiring the models using a Visual Analogue Scale. The Mann-Whitney test was used to compare the evaluators according to gender and age. The Wilcoxon test was used to compare the models according to gender. The Kruskal-Wallis and Dunn post hoc tests were used to compare the appliances according to design. A 5% significance level was used for all tests.

RESULTS

The clear aligner group showed the highest likelihood of being hired, followed by the group without orthodontic appliances, the groups with esthetic appliances (ie, conventional appliance with a transparent elastic ligature, and self-ligating esthetic appliance), and the groups with metallic appliances (ie, self-ligating metal appliance, conventional metallic appliance with gray elastic ligature, and conventional metallic appliance with blue elastic ligature).

CONCLUSIONS

Assuming all other qualifications of the applicants are equivalent, the use of an orthodontic appliance may influence job interviews. The better the esthetics of the appliance, the higher the likelihood of the individual being hired.

Lingual Orthodontic Treatment: Efficacy and Complications

Aims and Objectives:

The high esthetic demands led to the promotion of various esthetic appliances like lingual orthodontics. This study aimed to review clinical outcome and potential complications of lingual orthodontics to achieve an evidence-based decision for orthodontic therapies.

Materials and Methods:

A comprehensive electronic search was conducted from January 1975 to March 2019 which was limited to English language and administrations of lingual orthodontics treatment which evaluated its efficacy and potential complications. Data extraction was performed according to the PRISMA statement.

Results:

49 studies were selected and analyzed in this systematic review. The pain of lingual appliances starts a little earlier and lasts longer, and patients with lingual appliances experience more tongue discomfort and less cheek and lip pain and greater eating difficulties especially after placement and take a longer time to adapt to appliances. Lingual appliances generally cause more plaque accumulation and gingivitis especially in lingual anterior teeth; however, labial appliances are associated with high frequency in posterior maxillary teeth.

Conclusion:

This systematic review shows that despite the drawbacks of these appliances such as pain and eating difficulties, they can accomplish treatment goals with the same outcomes in comparison with conventional approaches, within the same duration and even lesser anchorage loss.

Facial Versus Skeletal Landmarks for Anterior-Posterior Diagnosis in Orthognathic Surgery and Orthodontics: Are They the Same?

PURPOSE

The purpose of this investigation was to evaluate diagnostic agreement in anterior-posterior (AP) categorization of the maxilla and mandible between a skeletal-landmark analysis and a facial-landmark analysis for treatment planning of orthognathic surgery and orthodontics.

MATERIALS AND METHODS

This retrospective, consecutive case series of adult patients who presented to the Mayo Clinic orthodontic department compared maxillary and mandibular AP diagnoses. Steiner's analysis of the sella-nasion-A point angle and sella-nasion-B point angle was used for a skeletal-landmark diagnosis. Element II of Andrews' 6 elements of orofacial harmony was used for a facial-landmark diagnosis. Both diagnoses were categorized as either deficient, optimal, or excessive for each jaw. Categorization of the skeletal landmark was determined by normative data, whereas the facial landmark provides a customized categorization unique to each individual.

RESULTS

Weighted κ statistics were completed to test agreement between the categories determined by the skeletal and facial landmarks. The maxilla showed poor agreement, and the mandible showed slight agreement.

CONCLUSIONS

No agreement was found for AP categorization of the maxilla and mandible between skeletal-landmark and facial-landmark analyses. Most mandibles were diagnosed as retrognathic by the facial landmark, whereas most were diagnosed as optimal by the skeletal landmark. When the 2 landmarks disagreed, the facial landmark defined the optimal position farther anterior. The landmark chosen for diagnosis will impact the optimal jaw position and can affect orthognathic and orthodontic outcomes.

Mouth Width and Cupid's Bow Estimation in a Southern African Population

Standards for estimating mouth width and Cupid's bow width in craniofacial approximation and superimposition are limited. Currently, the only guideline for mouth width, using direct skeletal references, is a general rule indicating a 75% inter-canine to mouth width ratio. The philtrum, which closely corresponds to the Cupid's bow, is said to be equal to the inter-superior prominences of the maxillary central incisors. This study tested these guidelines against newly generated regression models and mean values. Cone-beam CT scans of 120 black and 39 white southern African adults were used. Comparative hard and soft tissue measurements were taken using a 3D DICOM viewer. Regression equations accounting population, sex, and approximate age variables (20-39 and 40+ years), utilizing maxillary inter-canine width to estimate mouth width and maxillary central-lateral incisor junction width to estimate Cupid's bow width, performed statistically best. The regression models were more reliable than existing standards in validation tests.

Three-dimensional analysis of lip changes in response to simulated maxillary incisor advancement

OBJECTIVE

To assess the immediate response of lips in three dimensions (3D) resulting from simulated maxillary incisor advancement.

MATERIALS AND METHODS

Incremental maxillary incisor advancement was simulated by placing wax of increasing thickness (+2 mm, +4 mm, +6 mm) on the incisors of 20 participants, and the induced lip changes were recorded using 3D stereophotogrammetry. The induced displacement of lip landmarks was quantified using 3D image analysis software. Data were analyzed using a repeated-measures analysis of variance (ANOVA) after adjusting for age and sex of the study participants.

RESULTS

A large interindividual variation in lip response to simulated incisor advancement was observed. A significant overall effect on 3D lip changes was found for increasing values of simulated incisor advancement (F = 13.2; P < .001) as well as significant differences between anatomical landmarks of the lip (F = 7.4; P < .01). Most points moved outward and anterosuperiorly, except the midpoint and corners of the lip. Greatest movement was observed in the sagittal plane, followed by the vertical and transverse planes.

CONCLUSIONS

Maxillary incisor advancement significantly affects upper lip change in three planes of space: particularly the anteroposterior plane, in which the response to simulated advancement appears to be nonlinear.

Lingual Fixed Orthodontic Appliances May Be Associated With More Adverse Effects Than Buccal Appliances

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Adverse effects of lingual and buccal orthodontic techniques: A systematic review and meta-analysis. Ata-Ali F, Ata-Ali J, Ferrer-Molina M, Cobo T, De Carlos F, Cobo J. Am J Orthod Dentofacial Orthop 2016; 149:820-9.

SOURCE OF FUNDING

Not stated.

TYPE OF STUDY/DESIGN

Systematic review and meta-analysis.

Clear aligners' effects on aesthetics: evaluation of facial wrinkles

Background

To evaluate the facial aesthetic effects of orthodontic treatment performed with clear aligners and to compare it to an untreated control group, on lower third facial ageing in adult patients through the use of the Wrinkle Severity Rating Scale (WSRS) at the beginning (T0) and at the end (T1) of the study period.

Material and Methods

A clear aligners treated group (TG) of 68 patients was compared to a control group of 33 untreated patients (UG). Each group was divided in 2 subgroups according to age: subgroup 1 if under 40 years of age and subgroup 2 if over. Facial aesthetics of the lower third was evaluated at T0 and T1 by a panel of five aesthetic experts with WSRS.

Results

Statistically significant changes were found in all subgroups comparing WSRS scores at T0 and T1. The between group comparisons revealed that wearing clear aligners produces a statistically relevant improvement in lower third facial aesthetics both in younger (p< 0.05) and older (p< 0.001) patients.

Conclusions

The present retrospective cohort study has successfully shown that malocclusion therapy conducted through the use of clear aligners in a population of adults affected by dental crowding has beneficial effects on lower third facial ageing.

Key words:Orthodontics, clear aligners, facial aesthetics, facial wrinkles, compliance.

Adverse effects of lingual and buccal orthodontic techniques: A systematic review and meta-analysis

INTRODUCTION

The aim of this systematic review was to assess the prevalence of adverse effects associated with lingual and buccal fixed orthodontic techniques.

METHODS

Two authors searched the PubMed, EMBASE, Cochrane Library, and LILACS databases up to October 2014. Agreement between the authors was quantified by the Cohen kappa statistic. The following variables were analyzed: pain, caries, eating and speech difficulties, and oral hygiene. The Newcastle-Ottawa scale was used to assess risk of bias in nonrandomized studies, and the Cochrane Collaboration's tool for assessing risk of bias was used for randomized controlled trials.

RESULTS

Eight articles were included in this systematic review. Meta-analysis showed a statistically greater risk of pain of the tongue (odds ratio [OR], 28.32; 95% confidence interval [95% CI], 8.60-93.28; P <0.001), cheeks (OR, 0.087; 95% CI, 0.036-0.213; P <0.0010), and lips (OR, 0.13; 95% CI, 0.04-0.39; P <0.001), as well as for the variables of speech difficulties (OR, 9.39; 95% CI, 3.78-23.33; P <0.001) and oral hygiene (OR, 3.49; 95% CI, 1.02-11.95; P = 0.047) with lingual orthodontics. However, no statistical difference was found with respect to eating difficulties (OR, 3.74; 95% CI, 0.86-16.28; P = 0.079) and caries (OR, 1.15; 95% CI, 0.17-7.69; P = 0.814 [Streptococcus mutans] and OR, 0.67; 95% CI, 0.20-2.23; P = 0.515 [Lactobacillus]).

CONCLUSIONS

This systematic review suggests that patients wearing lingual appliances have more pain, speech difficulties, and problems in maintaining adequate oral hygiene, although no differences for eating and caries risk were identified. Further prospective studies involving larger sample sizes and longer follow-up periods are needed to confirm these results.

Age-related changes in the Brazilian woman's smile

The aim of this research was to evaluate age-related changes in the smile of Brazilian women. The sample consisted of 249 Brazilian women who had not undergone previous orthodontic treatment or facial surgery. They were divided into four groups, according to age: G1 (20-29), G2 (30-39), G3 (40-49) and G4 (50 or older). Standardized front view photographs were taken while smiling and at rest. Measurements were evaluated by ANOVA and post-hoc Tukey. The Chi-square test was applied for qualitative variables. Upper lip thickness at rest and exposure of upper incisors on smiling decreased with age. Most individuals (60.9%) exhibited a medium smile. High smiles were more often seen in G1 (45%) and less frequently in G4 (18.8%), whereas the opposite occurred with the low smile, i.e., G4 (21.9%) and G1 (6.7%). Variations among the groups were observed in the transverse exposure of the teeth on smiling. In G1 and G3, there was a balance between tooth exposures, so that the teeth were exposed as far as the premolars and/or molars. Most of the women (56.3%) in G2 exposed their teeth as far as the first molars on smiling, whereas most of those (40.6%) in G4 exposed their teeth only as far as the first premolars on smiling. As age increased, there was decreased exposure of the upper incisors, decreased upper lip thickness and lower exposure of teeth vertically and transversely.

The Role of Ideal Angles, Ratios, and Divine Proportions in Aesthetic Evaluation of Adolescents

OBJECTIVES

The aim of our study was to investigate whether the parameters of ideal angles, ratios, and divine proportions that have been previously mentioned in the literature influence the aesthetic evaluation of Turkish adolescents.

MATERIALS AND METHODS

A total of sixty patients (30 males and 30 females) were enrolled in this study. Ages of the subjects ranged from 9 to 17. Pre-treatment extra-oral photographs were taken to evaluate facial aesthetics. Two distinct panels consisting of 50 orthodontists and 50 laypersons were created for scoring the photographs of the patients. Scoring was performed using the VAS scale. Twenty-seven ratios and 19 divine proportions were measured in frontal photographs, and 26 angles were measured in profile photographs.

RESULTS

Pearson correlation was used to determine the relationship between the photograph analysis measurements and VAS scores, and then regression analyses were performed to disclose to what extent significant values may warrant the term beauty.

CONCLUSION

As a result of our investigations, none of the golden proportions was associated with facial aesthetics according to both orthodontists and laypersons. According to other angles and ratios that were measured, it was determined that orthodontists noticed the sagittal position of the lower jaw, the distance between the eyes and length of the face, whereas laypersons noticed only the distance between the eyes and length of the face.

LEVEL OF EVIDENCE V

This journal requires that the authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

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.

Photographic Facial Soft Tissue Analysis by Means of Linear and Angular Measurements in an Adolescent Persian Population

Objective : To obtain objective average measurements of the profile and frontal facial soft tissue to be used as a guide for aesthetic treatment goals. Methods and Materials : This observational study included 110 females and 130 males high school students aged 16-18 years. None of the subjects had any facial deformities. All of them and their parents gave consent to take part in this study. In each case, two standard photographs of profile and frontal views were taken 27 landmarks were digitized on photographs. The mean, standard deviation, and range for a total of 43 facial indices were calculated digitally by computer software. The Student’s t-test was used to compare males and females. Results : The ratio between the lower and middle facial thirds was one to one, but the height of the upper facial third was proportionally smaller than the other two-thirds in both sexes. Boys had greater nasal length, depth, and prominence than girls with statistically significant differences. Both upper and lower lips were more prominent in girls than in boys. All measurements of the chin showed sexual dimorphism characterized by greater chin height and prominence and deeper mentolabial sulcus. Boys had greater facial dimensions than girls. Mouth width, nasal base width, and intercanthal distance were significantly greater in boys. Conclusion : The labial, nasal, and chin areas showed sexual dimorphism in most of the parameters used in this study. Boys had larger faces, greater facial heights, longer nasal, labial, and chin lengths, and greater nasal, labial, and chin prominence.

Changes on facial profile in the mixed dentition, from natural growth and induced by Balters' bionator appliance

OBJECTIVE

The purpose of this study was to evaluate the facial profile changes induced by Balters' bionator appliance in Class II division 1 patients, at mixed dentition stage.

METHODS

The sample consisted of 28 pre-pubertal individuals at stages 1 and 2 of skeletal maturation (CVM), which were divided into two groups. The experimental group consisted of 14 individuals (7 boys and 7 girls, initial mean age of 8y12m) which were treated with Balters' bionator appliance for 14.7 months. The effects of treatment were compared to a control group of 14 subjects (7 boys and 7 girls, initial mean age of 8y5m) with Class II malocclusion, division 1, not orthodontically treated, which were followed up for 15.4 months. The statistical analysis was performed using Student's t test, at a significance level of 5%.

RESULTS

The results showed that the Balters' bionator appliance promoted a significant increase on the mentolabial angle, in addition to demonstrating a tendency to reduce the facial skeletal convexity, to restrict the maxillary growth and to increase the nasolabial angle and the lower anterior facial height.

CONCLUSIONS

It can be concluded that the Balters' bionator appliance improved the facial profile of children treated at mixed dentition stage.

Soft-tissue profile growth in patients with repaired complete unilateral cleft lip and palate: A cephalometric comparison with normal controls at ages 7, 11, and 18 years

INTRODUCTION

In this retrospective longitudinal study, we aimed to study differences in the soft-tissue profiles in growing children with clefts in comparison with controls through the period of facial growth from 7 to 18 years.

METHODS

Lateral cephalometric measurements made at 7 years (T1), 11.1 years (T2), and 17.9 years (T3) of age of 70 white children (35 boys, 35 girls) with complete unilateral cleft lip and palate (UCLP) who received primary lip and palate repair surgeries at The Hospital for Sick Children, Toronto, were compared with those of a control group of similar ages, sexes, and racial backgrounds, and having skeletal Class I facial growth, selected from the Burlington Growth Study. None of the included subjects had received any surgeries other than the primary lip and palate repairs, and none had undergone nasal septum surgery or nasal molding during infancy. Between-group comparisons were made at each time point using generalized linear models adjusted for age and sex effects. Longitudinal comparisons across all time points were conducted using the mixed model approach, adjusting for these effects and their interactions with time.

RESULTS

Bimaxillary retrognathism, progressive maxillary retrognathism, and increasing lower anterior face height with downward and backward growth rotation of the mandible in the UCLP group were seen. Unlike the hard-tissue face height ratio, their soft-tissue face height ratio was not affected. The upper lips in the UCLP group were shorter by 1.81 mm at T2 (P <0.001) and by 1.16 mm at T3 (P = 0.018), whereas their lower lips were 2.21 mm longer at T3 (P = 0.003). A reduced upper lip to lower lip length ratio at T2 and T3 (P <0.001) resulted. Their upper lips were relatively retruded by 1.44 mm at T1, 1.66 mm at T2, and 1.86 mm at T3 (all, P <0.001), and their lower lips were relatively protruded by 1.07 mm at T1 (P = 0.003), 1.40 mm at T2 (P <0.001), and 1.62 mm at T3 (P <0.001). Nose depths in the UCLP group were shallower by at least 1 mm from T1 to T3, and columellar length was shorter by almost 2 mm (all, P <0.001). Their columellae and nose tips rotated downward with growth, with the most significant rotations experienced from T2 to T3, and progressive reductions in their soft-tissue profile convexity were seen from T1 to T3 (P <0.001).

CONCLUSIONS

Key attributes of the imbalance in the soft-tissue profile in children with repaired UCLP were identified in the lip and nose regions. Although many profile differences were visible as early as 7 years of age, they became more apparent by 11 years of age and increased in severity thereafter. The short upper lip combined with a long lower lip resulted in the characteristic lip length imbalance, whereas the progressively retruding upper lip and protruding lower lip led to developing a step relationship in the sagittal lip profile during the adolescent growth period. Their columellae and nose tips rotated downward during this time.

A systematic review of individual motivational factors in orthodontic treatment: facial attractiveness as the main motivational factor in orthodontic treatment

Introduction. Physical, mental, and social consequences of malocclusion may impact the quality of life. The aim of this review is to describe main factors motivating parents for orthodontic treatment for their children. Methods. A systematic review study design was used to identify articles analyzing different motivational factors in orthodontic treatment appearing in Medline database, EMBASE, and Google Scholar. The search terms used were teasing, motivating factors, orthodontics, malocclusion, quality of life, smile attractiveness, and perception of malocclusion. Papers selected up to May 2013 included retrospective and prospective longitudinal studies, randomized control trials, cross-sectional studies, reviews, and meta-analyses. Results. 13 articles included in this review identified aesthetics as the main motivational factor in orthodontic treatment. Children mention teeth crowding, large overbite, missing teeth, and largest maxillary anterior irregularities also as motivational factors. Parents want their children to look nice and worry of being accused of neglecting parental duties. Conclusions. Dissatisfaction with one's appearance, dentist recommendation, interest and worries of parents, and the impact of peers who wear braces rank among the main motivation factors of seeking orthodontic treatment. Understanding these factors allows better planning of resources and better assessment of the requirements and priorities of treatment.

Relationships between facial features in the perception of profile attractiveness

OBJECTIVE

The aim of the study was to analyse the attractiveness of modifications of lip, nose or chin positions on profile photographs.

MATERIALS AND METHODS

A profile digital photograph was randomly selected among pictures of 50 models participating to a beauty contest and then reviewed by 10 orthodontists and 10 laypersons who unanimously rated the profile as attractive. The original picture (O) was modified so as to create protrusion and retrusion of the lips of 2,4 and 6mm, thus generating 6 new pictures (O-6, O-4, O-2, O+2, O+4, O+6). From the original picture 7 new pictures were generated: (N) with the nose protruded of 6mm and its combinations with lips protrusion and retrusion (N-6, N-4, N-2, N+2, N+4, N+6). In the same way, picture (C) was created with the chin protruded of 6mm and 6 combinations of protruded chin with protruded and retruded lips were generated (C-6, C-4, C -2, C+2, C+4, C+6). 15 orthodontists and 15 laypersons were asked to rate all the 21 pictures on Visual Analogue Scales (VAS).

RESULTS

The original picture reported the highest VAS scores. Comparing the series "C" and "N", the pictures with Nose protrusion show higher VAS scores if compared with pictures with chin protrusion (p<.05). When nose or chin protrusion is present, the pictures that shows lip protrusion (N+2, C+2) reported higher VAS scores (p<.05).

CONCLUSIONS

In cases of nose or chin protrusion, a compensatory lip protrusion improves the profile attractiveness. Nose protrusion seems to be more tolerated than a similar amount of chin protrusion.

Cephalometric floating norms as a guide toward a harmonious individual craniofacial pattern among Filipinos

OBJECTIVE

To construct a harmony box based on correlated cephalometric variables, which may serve as a valuable diagnostic tool in orthodontic treatment planning, by analyzing the harmonious relationships of existing individual craniofacial patterns among Filipinos.

MATERIALS AND METHODS

Eighty-one subjects, 37 females and 44 males, were selected from the student population of a University according to established inclusion criteria. Five cephalometric angular measurements were obtained and digitized. Pearson correlation coefficients described the high association among the five variables. The bivariate linear regression analysis was used to construct a harmony box, which contained the cephalometric floating norms of the five correlated variables. Multiple regression analysis and the standard error of the estimate were calculated to construct the harmony schema, which describes the individual craniofacial pattern.

RESULTS

Correlations between the five variables were significant at .001 and .05 levels. Linear regression equations with corresponding r(2) and standard error of the estimate (SE) were illustrated as the harmony box. The multiple correlation coefficient R, the adjusted R(2), and the SE when one of the five measured variables was predicted from the remaining four by means of a multiple regression analysis were displayed as the harmony schema.

CONCLUSION

The cephalometric floating norms describing the individual craniofacial pattern among Filipinos were established based on five correlated variables in the form of a harmony box.

Facial soft tissue depths in craniofacial identification (part I): An analytical review of the published adult data

With the ever increasing production of average soft tissue depth studies, data are becoming increasingly complex, less standardized, and more unwieldy. So far, no overarching review has been attempted to determine: the validity of continued data collection; the usefulness of the existing data subcategorizations; or if a synthesis is possible to produce a manageable soft tissue depth library. While a principal components analysis would provide the best foundation for such an assessment, this type of investigation is not currently possible because of a lack of easily accessible raw data (first, many studies are narrow; second, raw data are infrequently published and/or stored and are not always shared by some authors). This paper provides an alternate means of investigation using an hierarchical approach to review and compare the effects of single variables on published mean values for adults whilst acknowledging measurement errors and within-group variation. The results revealed: (i) no clear secular trends at frequently investigated landmarks; (ii) wide variation in soft tissue depth measures between different measurement techniques irrespective of whether living persons or cadavers were considered; (iii) no clear clustering of non-Caucasoid data far from the Caucasoid means; and (iv) minor differences between males and females. Consequently, the data were pooled across studies using weighted means and standard deviations to cancel out random and opposing study-specific errors, and to produce a single soft tissue depth table with increased sample sizes (e.g., 6786 individuals at pogonion).

Soft tissue profile after distal molar movement with a pendulum K-loop appliance versus cervical headgear

OBJECTIVE

To evaluate the soft tissue changes associated with the pendulum appliance that was supported with a K-loop buccally and to compare these treatment changes with a cervical headgear group.

MATERIALS AND METHODS

The records of 30 patients having skeletal Class I, dental Class II malocclusions were divided to two groups. Group 1 consisted of 7 girls, 8 boys (mean age, 15.0 +/- 3.4 years), and Group 2 consisted of 10 girls, 5 boys (mean age 14.2 +/- 2.9 years). The first group was treated with a pendulum appliance that was supported with a K-loop buccally, and the second group was treated with cervical headgear. Lateral cephalograms were taken at the beginning of treatment and at the end of distal molar movement. Treatment changes within the groups were analyzed using the paired t-test, and between group changes were analyzed with the independent t-test.

RESULTS

The results showed that the pendulum/K-loop appliance had no significant effect on skeletal and dental variables and soft tissue A point, upper lip thickness, and sagittal upper lip position relative to the E plane. A significant difference for the change in Vp-Ls distance was found in patients in the pendulum/K-loop group (P < .05). Patients in the cervical headgear group showed significant retrusion in skeletal, dental, and soft tissue measurements (P < .05).

CONCLUSIONS

The pendulum/K-loop appliance produces distal molar movement without causing any significant changes in the sagittal or vertical positions of either the jaw or the soft tissue profile.

Facial Profile Changes in Early Class II Correction with Cervical Headgear

Objective: To characterize the effects of early cervical headgear treatment on the facial profile of children in Class II division 1 malocclusion.

Materials and Methods: Forty children aged 9.1 (7.2–11.5) years with Class II division 1 malocclusion were treated using a cervical headgear appliance. The headgear consisted of a long outer bow bent upward 15° and a large expanded inner bow. Lateral cephalograms were taken before and after treatment, and the facial profile was estimated from the cephalograms. The results were compared to an age- and sex-matched normal cohort of 644 Finnish children.

Results: Class I molar relationship was achieved in all treated children. The treatment time was 1.6 (0.3–3.1) years on average. Compared to the controls, the treatment restricted the forward growth of maxillary A-point, and the SNA angle decreased 1.4° ± 1.2° per year (P &lt; .00001). Decreased maxillary prognathism was associated with decreased facial convexity, g-sn-pg (P = .02), and the ANB (P &lt; .00001) angles decreased compared to the controls. Upper lip protrusion (distance ls to sn-pg; P &lt; .00001) was decreased, and the nasolabial angle (cm-sn-ls) widened despite the increased facial inclination of the upper incisors (P = .0005). The treatment significantly decreased the gap between the lips (P = .0009) in their relaxed position.

Conclusion: Cervical headgear treatment in Class II correction is associated with a decreased facial convexity caused by the restriction of forward growth of the maxillary A-point, while the rest of the facial profile, including the mandible, continue to grow forward at a normal rate.

Knowledge-dependent pattern classification of human nasal profiles

OBJECTIVE

(1) To determine feature vector representations (geometric pattern parameters) that are effective in describing human nasal profiles, (2) to determine the number of code vectors (typical nasal patterns) that are mathematically optimized by applying the vector quantization method to each feature vector extracted for each subject, and (3) to determine the morphological traits of each code.

MATERIALS AND METHODS

Lateral facial photographs of 200 Japanese women recorded for orthodontic diagnosis were selected. Five anatomic landmarks were identified on each image together with a set of data points that constituted the contour of the facial profile. An eight-dimensional feature vector effective in distinguishing differences in nasal profile patterns was extracted from the data set using experts' knowledge of the anatomic traits of the nose. The vector quantization technique was applied to the feature vectors to provide the optimum number of nasal profile patterns.

RESULTS

The number of code vectors mathematically optimized was six, and the differences between vectors were maximized by morphological traits of the root, dorsum, tip, and base of the nose. Proportions of the number of image records classified into each code were 25.5%, 24.5%, 21.5%, 15.0%, 10.0%, and 3.5% from code 1 to code 6, respectively.

CONCLUSIONS

Classifying nasal profile patterns based on knowledge from a linguistic description was found to be more effective than a method based on uniform sectioning. The differences between vectors were maximized by morphological traits of the root, the dorsum, the tip, and the base of the nose.

Influence of chin prominence on esthetic lip profile preferences

INTRODUCTION

The purpose of this study was to determine the influence of chin prominence on preferred lip position in profile.

METHODS

Five "male" and 5 "female" silhouette profiles differing only in the degree of mandibular retrognathism or prognathism (-25 degrees, -18 degrees, -11 degrees, -4 degrees , and +3 degrees facial contour angles) were created. Using a computer animation program, the evaluators moved the upper and lower lips independently into the positions they deemed to be the most esthetic for each profile. The evaluators included white male and female adolescent orthodontic patients, parents of patients, and orthodontists.

RESULTS

In general, no differences in preferred lip position were found between the -11 degrees and -4 degrees profiles or between the -18 degrees and +3 degrees profiles, but preferences for each of the 3 profile groupings (-11 degrees and -4 degrees, -18 degrees and +3 degrees, and -25 degrees) were different. Fuller lip positions were preferred for the more extreme retrognathic and prognathic profiles, whereas more retrusive lip positions were preferred for the more average profiles. No differences were found among the 3 evaluator groups or between male and female evaluators. Scattered differences were found among lip preferences for male and female profiles.

The effects of computer-aided anteroposterior maxillary incisor movement on ratings of facial attractiveness

BACKGROUND

Before planning orthodontic treatment, it is necessary to understand societal preferences for facial esthetics. The anteroposterior (AP) position of the maxillary incisors affects the appearance of the soft tissue profile and can be manipulated by orthodontic techniques. To improve the ability to predict the most suitable maxillary incisor position, numerous cephalometric and profilometric measurements have been suggested. Among them are the Six Elements to Orofacial Harmony proposed by L. F. Andrews, whereby forehead angulation is used to dictate maxillary incisor sagittal position. Our aim was to evaluate differences in preference for the AP position of the maxillary incisor between orthodontic and lay panels.

METHODS

A smiling profile photograph was taken of a female subject who best fit the chosen soft tissue normative values and whose maxillary incisors were in an Element II position. The photograph was manipulated to simulate maxillary protrusion and retrusion at 1-mm increments to a maximum of +/-4 mm. Panels of orthodontists and nonorthodontists scored the attractiveness of the photographic variations according to a 100-mm visual analogue scale.

RESULTS

The 4-mm retrusive photograph was significantly less desirable than all others, which suggests that, from an esthetic standpoint, it is preferable to either leave a normally protrusive maxillary dentition where it is or advance rather than retract the maxillary anterior teeth. Orthodontic training did not significantly affect the magnitude of the ratings or pattern of preference in our sample.

CONCLUSIONS

Andrews' Element II provides an additional useful method to evaluate attractiveness relative to the maxillary incisor position.

Effect of orthodontic therapy on the facial profile in long and short vertical facial patterns

The purpose of the present study was to evaluate the effects of orthodontic treatment on the soft tissue facial profile of patients with long and short facial types. Orthodontic treatment records of 99 white long-faced and short-faced patients were analyzed to determine the effects of edgewise orthodontic treatment over an average period of 2.16 +/- 0.32 years. The average ages at the initiation and conclusion of treatment were 13.40 +/- 0.40 years and 15.61 +/- 0.29 years, respectively. A significant finding in this study was the large variability in soft tissue response to tooth movement. This variability was due to a wide dispersion of individual results between upper and lower lip change to maxillary and mandibular incisor movement anteriorly or posteriorly. Because of this soft tissue variability among individuals, definite differences between the long-faced and short-faced types could not be identified, nor was it possible to establish definite ratios for change in lip response to incisor movements.

Normal growth and development of the lips: a 3-dimensional study from 6 years to adulthood using a geometric model

A 3-dimensional computerised system with landmark representation of the soft-tissue facial surface allows noninvasive and fast quantitative study of facial growth. The aims of the present investigation were (1) to provide reference data for selected dimensions of lips (linear distances and ratios, vermilion area, volume); (2) to quantify the relevant growth changes; and (3) to evaluate sex differences in growth patterns. The 3-dimensional coordinates of 6 soft-tissue landmarks on the lips were obtained by an optoelectronic instrument in a mixed longitudinal and cross-sectional study (2023 examinations in 1348 healthy subjects between 6 y of age and young adulthood). From the landmarks, several linear distances (mouth width, total vermilion height, total lip height, upper lip height), the vermilion height-to-mouth width ratio, some areas (vermilion of the upper lip, vermilion of the lower lip, total vermilion) and volumes (upper lip volume, lower lip volume, total lip volume) were calculated and averaged for age and sex. Male values were compared with female values by means of Student's t test. Within each age group all lip dimensions (distances, areas, volumes) were significantly larger in boys than in girls (P < 0.05), with some exceptions in the first age groups and coinciding with the earlier female growth spurt, whereas the vermilion height-to-mouth width ratio did not show a corresponding sexual dimorphism. Linear distances in girls had almost reached adult dimensions in the 13-14 y age group, while in boys a large increase was still to occur. The attainment of adult dimensions was faster in the upper than in the lower lip, especially in girls. The method used in the present investigation allowed the noninvasive evaluation of a large sample of nonpatient subjects, leading to the definition of 3-dimensional normative data. Data collected in the present study could represent a data base for the quantitative description of human lip morphology from childhood to young adulthood.

A three-dimensional quantitative analysis of lips in normal young adults

OBJECTIVE

To supply information about (1) sex-related dimensions (linear distances and ratios, vermilion area, volume) of normal adult lips, (2) presence of sexual dimorphism, and (3) correlations between anthropometric characteristics of the lip and nose.

METHODS

The three-dimensional coordinates of soft tissue landmarks on the lips and nose were obtained using an optoelectronic instrument in 90 healthy young adult women and 90 healthy young adult men. From the landmarks, several linear distances (mouth width, total vermilion height, nose height, anatomic nose width, total lip height, upper lip height), the ratio of vermilion height to mouth width, and some areas (vermilion of the upper lip, vermilion of the lower lip, total vermilion) and volumes (upper lip volume, lower lip volume, total lip volume) were calculated. Linear correlation analyses between pairs of variables were also conducted within each sex.

RESULTS

All lip dimensions (distances, areas, and volumes) were significantly larger in men than in women (p<.005), but no sex differences were found in the vermilion height to mouth width ratio. Overall, mouth and nose dimensions were not significantly correlated, with the exceptions of the upper and lower lip volumes in both sexes and of the mouth and nose widths in the female sample, in which a modest part of the variance in one measurement could be explained by the other.

CONCLUSION

The dimensions of the mouth and the nose did not seem to be strictly related. Data collected in the present investigation could represent a database for the quantitative description of human lip morphology in adult subjects.