Maxillary Incisor Exposure Research Articles

Perioral age-related changes in smile dynamics along the vertical plane

To evaluate the changes in characteristics of perioral musculature at rest and when smiling, with respect to age and gender, measured along the vertical plane in a randomly selected sample of a North Indian population. Perioral musculature of 195 subjects (divided into three age groups) was recorded using standardized videographic methods. Two frames of each subject-at rest and widest posed smile-were analyzed for a comprehensive list of parameters. Data was evaluated using SPSS version 16 software. Two-way analysis of variance and post hoc least significant difference tests were conducted. Significant observations were increased resting upper lip length for females; decreased upper lip thickness, maxillary incisor exposure, and lip elevation for males; and increased smiling upper lip length for both sexes. With age, the smile gets narrower vertically, especially for the male population. The pattern of change observed in the present study must be considered and incorporated during treatment planning to deliver healthier and long-lasting results to patients of all age groups.

Assessment of changes in smile after rapid maxillary expansion

INTRODUCTION: This study evaluated changes in the smile characteristics of patients with maxillary constriction submitted to rapid maxillary expansion (RME). METHODS: The sample consisted of 81 extraoral photographs of maximum smile of 27 patients with mean age of 10 years, before expansion and 3 and 6 months after fixation of the expanding screw. The photographs were analyzed on the software Cef X 2001, with achievement of the following measurements: Transverse smile area, buccal corridors, exposure of maxillary incisors, gingival exposure of maxillary incisors, smile height, upper and lower lip thickness, smile symmetry and smile arch. Statistical analysis was performed by analysis of variance (ANOVA), at a significance level of 5%. RESULTS: RME promoted statistically significant increase in the transverse smile dimension and exposure of maxillary central and lateral incisors; maintenance of right and left side smile symmetry and of the lack of parallelism between the curvature of the maxillary incisal edges and lower lip border. CONCLUSIONS: RME was beneficial for the smile esthetics with the increase of the transverse smile dimension and exposure of maxillary central and lateral incisors.

Capture, analysis and measurement of images of speech and smile dynamics

INTRODUCTION: Dynamic analysis of smile and speech makes it easier to identify the features that define facial esthetics while allowing researchers to study different variables and observe the effects of aging. OBJECTIVE: The aim of this study is to present a method for capturing, analyzing and measuring video images to support the study of speech and smile dynamics. METHODS: Natural head positioning was standardized with the aid of a head holder (cephalostat). Image acquisition is performed with a video camera attached to a tripod, positioned at a fixed distance of 0.90 m. The subjects are trained to say out loud: "Tia Ema torcia pelo antigo time da Tchecoslováquia" and then to smile. The resulting images are fragmented and yielded four pictures that best represent a resting position, the least exposure of maxillary incisors, the greatest exposure of upper and lower incisors, and a posed smile. A freeware computer program called VIDEOMED was used to carry out measurements. CONCLUSION: The method presented in this study is an effective resource to record images captured during rest, speech and smile, thereby enabling a better understanding of changes in perioral soft tissues.

A Comparative Evaluation of Effect of Upper Lip Length, Age and Sex on Amount of Exposure of Maxillary Anterior Teeth

The aim was to evaluate the relationship of age, sex and lip length to the amount of exposure of maxillary incisors and canine teeth. Two-hundred subjects were enrolled in the study. All subjects were grouped according to the lip length and age. The exposure of maxillary central incisor and canines was measured with flexible millimeter ruler. Teeth exposure beyond the lower border of the upper lip was considered as positive exposure and the unexposed teeth were considered as negative exposure. In females of age group 20 to 29, 30 to 39, 40 to 49 and 50 to 59 years, the mean exposure of central incisor was 2.16, 2.1, 2.18 mm and that of canine was 0.04, -0.36, -0.44 mm. For male of age group 20 to 29, 30 to 39, 40 to 49 and 50 to 59 years exposed 2.04, 2.04, 1.84, 1.76 mm of central incisor respectively and 0.08, -0.52, -0.4 and -0.4 mm exposure of canine. Female subjects with lip length 10 to 15, 15 to 20, 21 to 25, 25 to 30 and 31 to 35 mm showed 3.7, 3.4, 2.3, 0.9, 0.25 mm exposure of central incisor and 0.35, -0.15, -0.7, -0.8, -0.6 mm exposure of canine, respectively. Male subjects exposed 3.4, 3.3, 2.05, 0.7, 0.15 mm of central incisor and 0.4, 0.3, -0.6, -0.95, -0.7 mm of canine respective to lip length. The range of exposure of maxillary central incisors was wider than that of canine. The average dimensions for maxillary canines relating to age and sex were closer to the extremes of the range. The canine position relative to the maxillary lip appeared to be a more predictable determinant. The result of the study can be used as a reference according to the age, sex and the lip length of the patient to correctly place maxillary anterior teeth in prosthesis.

Soft-tissue cephalometric norms in a South Indian ethnic population

An esthetically pleasing smile is a key determinant of successful orthodontic treatment and patient satisfaction. The great variance in soft-tissue drape of the human face complicates accurate assessment of the soft-tissue profile. Variability is also characteristic of different faces and facial types, and normative data based on 1 population group do not represent all. This study was undertaken to establish norms for a South Indian ethnic population. The sample comprised lateral cephalograms taken in natural head position of 60 normal subjects (30 men, 30 women). The cephalograms were analyzed with a soft-tissue cephalometric analysis for orthodontic diagnosis and treatment planning, and the Student t test was used to compare the means of the 2 groups. Statistically significant differences were found between South Indian men and women in certain key parameters. Men have thicker soft-tissue structures and a more acute nasolabial angle than women. Men have longer faces, and women have greater interlabial gap and maxillary incisor exposure. Men have more deep-set facial structures than women. Compared with established norms for white people, South Indian subjects have more deep-set midfacial structures and more protrusive dentitions. Statistically significant differences were found between South Indian men and women in certain key parameters. Differences were also noted between white and South Indian faces.

The kinetics of anterior tooth display

A survey has been presented that correlates measurements of upper lip type, sex, race, and age of dentulous patients with the amount of exposure of the maxillary and mandibular anterior teeth with the lips gently parted and in the resting position. Perhaps the most interesting finding was the gradual reduction in the amount of maxillary central incisor exposure with an increase in age, accompanied by a gradual increase in the mandibular tooth exposure. The importance of the amount of mandibular teeth seen in complete dentures has not been sufficiently emphasized in previous literature.

Superior repositioning of the maxilla: Stability and soft tissue osseous relations

The skeletal stability and soft-tissue changes associated with superior repositioning of the maxilla by Le Fort I osteotomy or simultaneous anterior and posterior maxillary osteotomies was studied in thirty patients by means of a computerized craniofacial model. Excellent skeletal stability was demonstrated 14 months postoperatively. Postsurgically, the reduction in lower face height and amount of maxillary incisor exposure resulted in improved facial balance. The use of a computerized osseous and soft-tissue craniofacial model has added a new dimension to evaluation of surgical changes associated with correction of dentofacial and craniofacial deformities.