Incisor Exposure Research Articles

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.

上下顎同時骨延長術を施行した著しい垂直的上顎劣成長を伴う下顎前突症の1例

When maxillary downgraft is performed for patients with severe maxillary deficiency, postoperative stability is sometimes insufficient. We report a case of mandibular protrusion with excessive vertical maxillary deficiency treated with simultaneous maxillo-mandibular distraction osteogenesis using alveolar distractors.A 25-year-old male patient visited our orthodontic clinic for treatment of his chief complaint that his upper incisors were invisible upon smiling. Upon examination, he was diagnosed as mandibular overgrowth with excessive vertical maxillary deficiency. Simultaneous maxillo-mandibular distraction osteogenesis was performed for considerable downward movement of the maxilla. Le Fort I osteotomy and bilateral inverted L osteotomy of the mandible were performed under general anesthesia. Bilateral alveolar distractors were set to the maxilla. After maxillo-mandibular fixation, distraction osteogenesis was performed downward by 10.5mm. Although slight relapse occurred 1 year after surgery and the final total amount of distraction was 9.0mm, the facial height and profile were improved and adequate exposure of the upper incisors was obtained.

Soft tissue cephalometric analysis applied to Himachali ethnic population

Introduction: The modern society considers facial attractiveness as an important physical attribute. The great variance in soft tissue drape of the human face complicates accurate assessment of the soft tissue profile, and it is a known fact that facial features of different ethnic groups differ significantly. This study was undertaken to establish norms for Himachali ethnic population. Materials and Methods: The sample comprised lateral cephalograms taken in natural head position of 100 normal individuals (50 males, 50 females). The cephalograms were analyzed by Arnett soft tissue cephalometric analysis for orthodontic diagnosis and treatment planning. Student's t-test was used to compare the means of the two groups. Results: Statistically significant differences were found between Himachali males and females in certain key parameters. Males have thicker soft tissue structures and a more acute nasolabial angle than females. Males have longer faces and females have greater interlabial gap and maxillary incisor exposure. Males have more deep-set facial structures than females. Conclusions: Statistically significant differences were found between Himachali males and females in certain key parameters. Differences were also noted between other ethnic groups and Himachali faces.

Clinical and radiographic evaluation of maxillary central incisors exposure in patients undergoing maxillary advancement.

Introduction: Patients with dentofacial deformities may undergo orthodontic or orthodontic-surgical treatment. Both modalities can affect esthetics. Objective: This study aims to evaluate clinical and radiographic changes in exposure of maxillary central incisors occurring after orthognathic surgery for maxillary advancement. Methods: A total of 17 patients who underwent orthognathic surgery for maxillary advancement between September, 2010 and July, 2011 were selected. Exposure of maxillary central incisors was evaluated clinically and by lateral cephalograms. Measurements were taken one week before and three months after surgery. Data were paired in terms of sex, age, nasolabial angle, height and thickness of the upper lip, the amount of maxillary advancement, clinical exposure and inclination of maxillary central incisor by statistical tests (CI 95%). Results: After maxillary advancement, incisor clinical exposure had increased even with relaxed lips and under forced smile. Moreover, there was a mean increase of 23.33% revealed by lateral cephalograms. There was an inverse correlation between upper lip thickness and incisors postsurgical exposure revealed by radiographic images (p = 0.002). Conclusions: Significant changes in the exposure of maxillary central incisors occur after maxillary advancement, under the influence of some factors, especially lip thickness.

Multidimensional esthetic evaluation of patients with a cleft lip and palate wearing a maxillary partial removable dental prosthesis: A 5-year retrospective study

Statement of problemNo published quantitative or qualitative studies are available of the 2-dimensional (2D) and 3D esthetic evaluation of patients with a cleft lip and palate (CLP) wearing a maxillary partial removable dental prosthesis (MPRDP). PurposeThe purpose of this retrospective clinical study was to qualitatively and quantitatively evaluate the facial esthetic improvements of patients with CLP wearing an MPRDP for 5 years by using 2D cephalometric and 3D photogrammetry methods. Material and methodsSix patients, 2 men and 4 women, with CLP deformity were recruited and treated with an MPRDP by the same dentist over 5 years. Results of the clinical examination were recorded before and after wearing the MPRDP. Sella-nasion-A (SNA) point, the U1-SN, 0-meridian to SN, nasolabial angle, and maxillary incisor exposure were measured by 2D cephalometric analysis before and after wearing the MPRDP. 3D photographs were captured by 3dMD software. Geomagic Spark Studio software was also used to measure the patients’ improved upper lip projection after the MPRDP was worn. The paired sample t test was used to compare the participants (α=.05). ResultsU1-SN (P<.05) and 0-meridian to SN (P<.01) had significant deviation statistically. After patients underwent clinical examination, SNA and nasiolabial angles were found to have improved, although no statistical significance was observed. ConclusionsA maxillary partial removable dental prosthesis (MPRDP) can advance the upper lip forward, restoring the subnasal and upper lip projection. Patients’ nasiolabial angles with MPRDPs were decreased, which led to a more harmonious facial contour.

Dimensional analyses of frontal posed smile attractiveness in Japanese female patients.

To identify appropriate dimensional items in objective diagnostic analysis for attractiveness of frontal posed smile in Japanese female patients by comparing with the result of human judgments. Photographs of frontal posed smiles of 100 Japanese females after orthodontic treatment were evaluated by 20 dental students (10 males and 10 females) using a visual analogue scale (VAS). The photographs were ranked based on the VAS evaluations and the 25 photographs with the highest evaluations were selected as group A, and the 25 photos with the lowest evaluations were designated group B. Then 12 dimensional items of objective analysis selected from a literature review were measured. Means and standard deviations for measurements of the dimensional items were compared between the groups using the unpaired t-test with a significance level of P < .05. Mean values were significantly smaller in group A than in group B for interlabial gap, intervermilion distance, maxillary gingival display, maximum incisor exposure, and lower lip to incisor (P < .05). Significant differences were observed only in the vertical dimension, not in the transverse dimension. Five of the 12 objective diagnostic items were correlated with human judgments of the attractiveness of frontal posed smile in Japanese females after orthodontic treatment.

Upper incisor exposure and aging: Perceptions of aesthetics in three age groups

BackgroundSeveral studies point to age-related changes in the smile due to muscle and bone changes. This study aimed to assess, in three age groups, the perception of the smile's aesthetics at various degrees of upper-incisor exposure. MethodsThe exposure of the upper incisors in the smile of a female patient aged 30 years was altered at 1-mm increments (range: +2 to −13 mm). The images were presented, in random and descending order of extent of upper-incisor exposure, to laypeople stratified by age (15–19, 35–44, and 65–74 years). The participants rated the attractiveness of the images using a 10-cm visual analog scale. The mean scores of each image were calculated to determine the differences in perceptions between the age groups. ResultsOverall, the groups rated the most attractive extent of upper-incisor exposure as follows: group aged 15–19 years, 0 mm; 35–44 years, −1 mm; and 65–74 years, −7 mm. ConclusionsBased on the findings from this study, age is an important factor in the perception of the aesthetics of a smile, with younger people preferring a smiles with greater dental exposure and older people preferring less dental exposure.

Prospective assessment of maxillary advancement effects: Maxillary incisor exposure, and upper lip and nasal changes

Our aim was to assess changes in maxillary incisor exposure, and upper lip and nasal soft tissues with maxillary advancement with or without impaction, accounting for the use of cinch sutures and VY closures. This was a prospective study of 41 consecutive patients undergoing maxillary advancement with or without impaction. Lateral cephalometric radiographs and clinical measurements were taken preoperatively and up to 6 months postoperatively by 1 examiner. Thirty-one patients (19 female, 12 male) with a mean age of 25.5 years (range, 16.9-49.9 years) completed the study. Twenty-six received bimaxillary surgery. Fifteen had simple closures, 6 had cinch sutures, and 10 had alar base cinch and VY closures. The mean amounts of maxillary advancement and impaction were 3.34 and 1.6 mm, respectively. Soft tissues followed increasingly more closely the hard tissue advancement from pronasale to stomion superius. Mean maxillary incisor exposure increased at rest (0.5 mm) and on smiling (1.0 mm). The nasolabial angle increased (1.88°) because of columella upturning. Alar base width (3.09 mm) significantly increased. Soft to hard tissue horizontal ratios increased progressively from pronasale to stomion superius. Alar base cinch and VY closures increased these further. Maxillary incisor display changes were partly explained by presurgical upper lip thickness and soft tissue manipulation. Nasolabial angle increased, and cinch sutures seemed to increase this further. Alar base width increased significantly, and the cinch sutures did not significantly limit this.

Soft tissue changes after a combined lefort I and anterior maxillary osteotomy: A clinical and cephalometric study

Background: Orthognathic Surgery is indicated in severe skeletal disharmony on the best means of improving functional facial esthetic. Assessment of the facial harmony in relation to soft tissue contour the thickness of the tissues, the lip length to postural tone plays an important role. This article aims determining the changes of the soft tissue profile cephalometrically after maxillary osteotomy. Material and Methods: The entire concept of orthognathic surgery involves the identification of the hard and soft tissue deformity by clinical examination, cephalometric radiographs, models and photographs. This study is to assist the pre and post-operative soft tissue changes clinically including width of the nasal bone and upper incisor exposure of rest and cephalometrically including nasolabial angle, facial convexity, lip protuberance and inter-labial gap by using Rickets E Line, Steiner's S Line, Merrifield's Z Angle and Holdaway Soft Tissue Analysis. Results: There is significant dramatic improvement in the soft tissue profile cephalometrically after maxillary osteotomy. Conclusion: The conclusion of the study is that there is a change in the soft tissue in relation to the hard tissue movement, and also the stability of the soft tissue profile was established by rigid fixation of bony segments.

THE ORTHODONTIC TREATMENT AND ONE YEAR FOLLOW UP OF AN ADULT CASE WITH SEVERE OPENBITE

Anterior open bite is an abnormal condition that is caused by dental, skeletal, functional, and pathological factors in dental arches and jaws. An adult woman having Class I relationship on the right side, Class II relationship on the left side and severe anterior open bite with inadequate maxillary incisor exposure demanded treatment without surgical approach. Treatment was performed with preadjusted edgewise appliances accompanying extraction of maxillary left first premolar. As a result, open bite abnormality was treated with satisfactory esthetic outcome coupled with an ideal overjet and overbite relationship.

Impacted Maxillary Central Incisors Associated with Bilateral Mesiodentes: A Case Report

The purpose of this paper was to present the surgical exposure and orthodontic treatment of an 11-year-old boy with horizontally impacted permanent maxillary central incisors associated with bilateral mesiodentes. Panaromic and upper anterior occlusal radiographs showed horizontally impacted maxillary central incisors, vertically impacted molariform mesiodens, and rotated mesiodens located at the site of the maxillary right central incisor. The treatment plan included extraction of the erupted mesiodens, surgical extraction of the impacted mesiodens, surgical exposure of the permanent central incisors, and orthodontic traction and alignment to achieve a normal occlusion. After 14 months of treatment, the central incisors erupted into the oral cavity. The impacted maxillary central incisors were successfully positioned to their proper alignment via surgical crown exposure and orthodontic traction. Ideal overjet, overbite, and Class I molar and canine relationships were also achieved. At the completion of treatment, the exposed incisors exhibited an acceptable gingival contour and attached gingiva. After 2 years of follow-up, a stable occlusion was maintained with only minor relapse at the right central incisor.

Evaluation of smile esthetics in central India

Objectives: This study was undertaken: (1) To establish static norms in the central India population for the various smile parameters. (2) To analyze and quantify the sexual dimorphism of esthetic smile. Settings and Design: Hundred subjects (50 males and 50 females) with an average age of 14.5 years with a pleasing smile were selected for the study. Static photographs with posed smile in natural head position (NHP) were taken. Materials and Methods: Following smile parameters were quantified using Adobe Photoshop ruler software: Maxillary incisor exposure (MIE) (mm), smile index (SI) (mm), smile arc, buccal corridor ratio (%), Most posterior maxillary tooth visible, anterior height of the smile (%), posterior height of the smile (%). Statistical Analysis: The data were compiled systematically. Statistical analysis was done using Statistical Package of Social Sciences (SPSS version 17.0). For MIE and SI, Unpaired t-test was applied. Chi-square test was applied for most posterior maxillary tooth visible, smile arc buccal corridor, anterior height of smile, and posterior height of smile. Results: The mean value of MIE was found to be 7.76 mm and 8.82 mm in boys and girls, respectively. SI showed a mean value of 8.26 for boys and 7.91 for girls. Girls displayed second premolar commonly in contrast to boys, who displayed first premolar. Parallel smile arc was noted more frequently in females, while males displayed flat smile arc commonly. Conclusion: Orthodontists, being smile architects, have the responsibility to design and create smiles. Smile analysis should be an integral part of dental/orthodontic treatment planning and mechanotherapy.

Arnett's Soft-tissue Cephalometric Analysis Norms for the North Indian Population: A Cephalometric Study

Objective: To determine the soft-tissue cephalometric norms as per Arnett’s analysis for male and female subjects of North Indian population and to compare these cephalometric norms with Arnett’s norms for Caucasian population. Materials and methods: Frontal and profile photographs of 150 subjects with normal occlusion and pleasing profile were rated by a panel of judges, from which 50-male and 50-female subjects were selected and their lateral cephalograms were taken for the present study. Arnett’s soft-tissue cephalometric analysis (STCA) was done on these cephalograms using Nemotech cephalometric software. Mean values of various parameters were obtained and these values were compared to Arnett’s norms for Caucasian population using Student t-test. These values were also compared among males and females of North Indian population. Results: High overjet, thicker soft-tissue, less facial length, retruded lower face and midface and convex profile were observed in the North Indian population as compared to Caucasian population. Males of North Indian population have thicker soft-tissue structures, more acute nasolabial angle, longer faces and more deep-set facial structures than females whereas females have greater interlabial gap and maxillary incisor exposure. Conclusion: Statistically significant differences in certain parameters were found between North Indian population and Caucasian population and also between males and females of North Indian population.

Improvement in smile esthetics following orthodontic treatment: A retrospective study utilizing standardized smile analysis

To quantify smile esthetics following orthodontic treatment and determine whether these changes are correlated to the severity of the initial malocclusion. A standardized smile mesh analysis that evaluated nine lip-tooth characteristics was applied to two groups of successfully treated patients: group 1 (initial American Board of Orthodontics Discrepancy Index [DI] score<20) and group 2 (initial DI score>20). T-tests were used to detect significant differences between the low-DI and high-DI groups for baseline pretreatment measurements, baseline posttreatment measurements, and changes from pre- to posttreatment. A Spearman correlation test compared the initial DI values with the changes in the nine smile measurements. Five of the smile measurements were improved in both groups following orthodontic treatment. Both groups demonstrated improved incisor exposure, an improved gingival smile line, an increase in smile width, a decreased buccal corridor space, and an improvement in smile consonance. Spearman correlation tests showed that initial DI value was not correlated to changes in any of the individual smile measurements. Smile esthetics is improved by orthodontic treatment regardless of the initial severity of the malocclusion. In other words, patients with more complex orthodontic issues and their counterparts with minor malocclusions benefitted equally from treatment in terms of their smile esthetics.

The Extent of Chin Ptosis and Lower Incisor Exposure Changes Following the Osseous Genioplasties

The incision and dissection of the mentalis muscles are inevitable to access the osteotomy line during genial surgery. As the mentalis muscles elevate the central lower lip and support the lip vertically, inadvertent scarring or lengthening of these muscles may lead to lip incompetence and may increase the lower incisor exposure (LIE) that will cause an unaesthetic result. The aim of this study was to evaluate the extent of lip ptosis, LIE, and other soft-tissue changes following different types of osseous genioplasty procedures.Twenty-nine patients (18 females, 11 males) were included in this study. Patients were classified into 3 groups with respect to their genial movement type as genial setback (n = 10), genial advancement (n = 10), and vertical reduction (n = 9). Preoperative and postoperative lateral cephalograms were analyzed to evaluate the horizontal and vertical soft-tissue changes of the lower lip and chin in the 3 genioplasty groups. The statistical evaluations were performed with regression analysis. The mean increase in the LIE was 1.88 mm. Lower incisor exposure and soft-tissue thickness at pogonion were increased significantly in all patients (P < 0.05). Statistically significant differences for lower lip length and vertical position of soft-tissue supramentale values were detected in patients who underwent vertical reduction genioplasty (P < 0.05). Genioplasty procedures requiring the mentalis muscle release cause a 1.88-mm increase in LIE. Vertical positional alterations of the lower lip were especially observed following the vertical reduction genioplasty. Clinician should be aware of this consequence in the course of treatment planning.

Longitudinal study of cephalometric soft tissue profile traits between the ages of 6 and 18 years

To study the longitudinal changes in 19 soft tissue cephalometric traits (according to the Bergman cephalometric soft tissue facial analysis). Cephalograms and photographs of 40 subjects (20 male, 20 female, from the Burlington Growth Centre) that were obtained at ages 6, 9, 12, 14, 16, and 18 years were used. Subjects were orthodontically untreated whites and had Class I dentoskeletal relationships (ideal overjet and overbite). Images were obtained with the lips in a relaxed position or lightly touching. Three groups of soft tissue traits were identified: (1) traits that increased in size with growth (nasal projection, lower face height, chin projection, chin-throat length, upper and lower lip thickness, upper lip length, and lower lip-chin length); (2) traits that decreased in size with growth (interlabial gap and mandibular sulcus contour [only in females]); and (3) traits that remained relatively constant during growth (facial profile angle, nasolabial angle, lower face percentage, chin-throat/lower face height percentage, lower face-throat angle, upper incisor exposure, maxillary sulcus contour, and upper and lower lip protrusion). Current findings identify areas of growth and change in individuals with Class I skeletal and dental relationships with ideal overjet and overbite and should be considered during treatment planning of orthodontic and orthognathic patients.

Combining traditional techniques to correct anterior open bite and posterior crossbite

The treatment of anterior open bite often requires the use of skeletal anchorage to prevent excessive eruption of the posterior teeth and consequent downward rotation of the mandible. However, this procedure might not always be accomplished. This article reports the successful treatment of an anterior open bite and a posterior crossbite in a young boy, combining traditional techniques and involving high-pull maxillary traction to help growth to correct the skeletal Class II malocclusion without skeletal anchorage. The vertical dentoalveolar contribution of maxillary growth was also favorable to close the bite, whereas cross-elastics corrected the axial inclination of the mandibular posterior teeth, eliminating the inverted posterior crossbite. The open bite was completely closed with edgewise appliances, which also achieved normal overjet, intercuspation, and incisor exposure on smiling. Traditional mechanics for the treatment of open bite and crossbite remain a useful alternative when patients do not accept skeletal anchorage.

Evaluation of the relationship between upper incisor exposure and cephalometric variables in Korean young adults

ObjectiveThe purpose of this study was to classify Korean young adults into 3 groups on the basis of upper incisor exposure rates (UIERs) and to compare the skeletal, dental, and soft tissue variables.MethodsSamples were obtained from 127 students at the College of Dentistry, Wonkwang University in South Korea. Facial photographs of frontal posed smiles and lateral cephalograms of the subjects were taken. The subjects were divided into 3 groups on the basis of UIERs and 20 measurements were compared among the 3 groups. The correlations between the variables were determined.ResultsMale and female subjects showed significant differences in the group distribution. Male subjects showed higher frequencies of low smiles, and female subjects showed higher frequencies of high smiles. The vertical height of the anterior alveolar process of the maxilla directly correlated with the UIER. However, the UIER showed no significant correlation with the vertical height of the anterior basal bone or the inclination of the upper incisor axis. In female subjects, the upper central incisor clinical crown length showed an inverse correlation with the UIER. However, this variable showed no significant correlation with the UIER in male subjects.ConclusionsThe UIER was directly correlated with the levator muscle activity of the upper lip and inversely correlated with the upper lip thickness, yet there was no correlation between the UIER and upper lip length at rest.

Do the smiles of the world's most influential individuals have common parameters?

The aim of this study was to determine - on the basis of the most recent yearly listings - whether there were any common measurable variables associated with the smiles of the world's most influential people. A total of 168 subjects were selected from the lists of Time magazine's 100 most influential people during the period 2006-2010. Smiling frontal view photographs were obtained. Thirty-six variables for each subject were traced and measured using photogrammetric analysis to obtain qualitative and quantitative proportions and measurements. Differences with respect to gender, occupation and year of listing were tested to 95% significance, using the Student's t-test and the Kruskal-Wallis test. The chi-squared test was used for qualitative variables. Irrespective of gender or occupation, the similar quantifiable characteristics of the smiles of the most influential subjects were the following: vertical upper lip proportion, smile width, incisor exposure, buccal corridor ratio, smile symmetry index and intra-dental proportions (P>0·05). Other qualitative standards were as follows: smile symmetry, the buccal corridors and smile arc, direction of occlusal cant and the degree of deviation between maxillary and facial midlines. Differences were found for gingival display and smile height parameters (P=0·001). The smiles of the world's most influential people revealed common standards, regardless of occupation or gender, which may play a decisive role in the expressions of influential faces.

The relationship between smile attractiveness and esthetic parameters of patients with lateral agenesis treated with tooth recontouring or implants

The relationship between smile attractiveness and esthetic parameters of patients with lateral agenesis treated with tooth recontouring or implants Luciana Manzotti De-Marchi,1 Núbia Inocencya Pavesi Pini,2 Renata Corrêa Pascotto31Department of Dentistry, University Center of Maringá-CESUMAR, Maringá-PR/Brazil; 2Piracicaba Dental School, State University of Campinas, Piracicaba-SP/Brazil; 3Department of Dentistry, State University of Maringá, Maringá-PR/BrazilBackground: The purpose of this study was to associate smile esthetic judgment with dentofacial attributes of patients with unilateral and bilateral agenesis of maxillary lateral incisors treated with recontouring of canines or implants and patients with no agenesis (control).Material and methods: Forty-six participants were divided into two groups: those treated with recontouring (N = 26) and those treated with implants (N = 20). The participants in the control group (N = 22) were selected among dentistry students at the State University of Maringá, Brazil. Photographs of posed smiles (17 cm × 10 cm) were evaluated with a 100-mm Visual Analog Scale. Smile attractiveness was judged by two groups: laypersons and dentists (N = 20 in each group). Judgment was classified into Unpleasant and Pleasant. Measurements of 11 smile attributes were done with ImageTool Version 3.0. These measurements were correlated with the type of judgment using the Pearson correlation coefficient.Results: The two groups of evaluators showed no rating difference (analysis of variance, P = 0.64), thus they were placed into a single group. No significant correlation was found between esthetic judgment and six smile attributes (incisor exposure, interlabial gap, width 3 to 3, smile index, right buccal corridor, and buccal corridor ratio). The control group showed more correlations with the unpleasant judgment type than the other groups.Conclusion: Some correlations between smile attributes and esthetic judgment were found, but other features of smiles not evaluated in this study may interfere in smile attractiveness.Keywords: esthetic, dental agenesis, attractiveness, dental implants, composite resin, perception