A study to correlate various facial landmarks with intercanine distance

Ideal interaction of dental and facial beauty proportions highly influences a harmonious facial appearance. Racial anatomical variations have been significantly noted and using these norms during prosthodontic rehabilitation will be greatly helpful in successful treatment outcome. Aim: The present study aims to correlate various facial landmarks (interpupillary distance [IPD], intercanthal width, bizygomatic width [BZW], and interalar width) with intercanine distance (ICaD) in Indian young adults to determine the mesiodistal width of the maxillary anterior teeth in edentulous patients. Setting and Design: This is an observational cross-sectional study. Materials and Methods: This study was conducted in 500 individuals ranging in age from 18 to 28 years. IPD, intercanthal width, BZW, and interalar width were measured with a digital caliper (accuracy - 0.01 mm). A “T-” shaped flat metal plate called “canine tip marker” was made to mark the tips of the maxillary canines, which were further measured with the digital caliper. The data were summarized in table form and were statistically analyzed. Statistical Analysis Used: Student's t-test and ANOVA test were used. Results: A significant correlation (P < 0.001) was found between these landmarks with ICaD, in which interalar width shows highest degree of correlation (r = 0.639). ANOVA test showed that maximum number of individuals had < 5% variability range between actual values and calculated values of ICaD for all extraoral facial landmarks except intercanthal width. Conclusion: Combination of various facial and oral factors should be considered while selecting artificial teeth. Regression equations obtained can be well used during teeth selection to achieve a significant result.

Stress pattern generated by different post and core material combinations: A photoelastic study.

Objective: To analyze the effect of different combinations of post and core materials on stress distribution in dentin of an endodontically treated tooth. Materials and Methods: This was an experimental stress analysis study. Models were made in photoelastic material, i.e., epoxy resin. Different combinations of post and core materials used were: Glass fiber post with composite core, stainless steel post with composite core, and cast metal post and core. Stresses generated were frozen, models were sliced and viewed under circular polariscope, and photographs were taken. Stress was calculated by counting the number of fringes. Results: For the combination of glass fiber post with composite core, the shear stresses calculated were 1.196, 1.196, and 2.898 MPa in the apical, mid-root, and cervical region, respectively. For the combination of stainless steel post with composite core, the apical, mid-root and cervical stresses were 1.534, 0.511, and 2.557 MPa, respectively. For cast metal post and core, the apical, mid-root, and cervical stresses were 0.852, 0.511, and 1.534 MPa, respectively. Conclusion: The cervical region of the teeth is subjected to the highest stresses irrespective of the material used. The stainless steel post with the composite core generated the highest stress concentration in different regions. A glass fiber post generated a uniform stress distribution. A cast metal post and core combination generated lesser stress than the other combinations. The vast difference in the elastic modulus of the restorative materials can lead to nonuniform stress distribution and concentration of stresses in different areas which can have deleterious effect on the survival of already compromised teeth and restoration. Such combinations should be avoided and the material which has an elastic modulus close to that of dentin should be preferred.

A study to evaluate the effect of oral stereognosis in acceptance of fixed prosthesis.

Aims: The aim of the study was to evaluate and compare the oral stereognostic ability and satisfaction for fixed prosthesis in human being. Materials and Methods: The present study was carried out on 40 subjects, the purpose being to investigate the relation of oral perception to diagnostic and therapeutic procedures. Two types of cast metal crowns-one had morphology closely resembling original tooth and other one confirmed to ideal contours were constructed on endodontically treated posterior tooth. One cast metal crown was randomly selected from two cast metal crown and fitted on prepared tooth. Oral stereognostic score of subject was determined by correct response to questionnaire based on the recognition ability of subjects. Patient satisfaction level was checked by psychometric parameter Likert scale. Same procedure was repeated with other type of cast metal crown. Results: Data obtained were compared by paired and unpaired two sample t-test. Oral stereognostic score and satisfaction score were found to be higher for cast metal crown with morphology resembling to original tooth due to recognition and discriminatory ability of subjects and recall-memory. Oral stereognostic level was found to be higher in younger than older subjects. The level of satisfaction was found to be higher in older subjects than younger subjects. Conclusion: It was concluded that acceptance of fixed prosthesis is not only based on dentist's routine procedure of treatment and patient's judgment about oral health, function, and esthetics, but also depends upon patient's oral perception and discriminatory skill for external morphology of fixed prosthesis.

Impact of delayed prosthetic treatment of velopharyngeal insufficiency on quality of life.

Palatopharyngeal dysfunction may take place when palatopharyngeal valve is unable to perform its own closing due to a lack of tissue (palatopharyngeal insufficiency) or lack of proper movement (palatopharyngeal incompetence). Palatopharyngeal insufficiency induces nasal regurgitation of liquids, hypernasal speech, nasal escape, disarticulations and impaired speech intelligibility. Prosthetic management of palatopharyngeal insufficiency requires a close co-operation between an otolaryngologist and a speech pathologist. As a result, the patient can be socially and physically rehabilitated with the improved speech quality as well as prevention of leakage of liquids.

Mechanical properties of denture base resins: An evaluation.

Background: Acrylic resin dentures are susceptible to fracture after clinical use, which is a problem of concern in prosthodontics. Impact failure outside the mouth and flexure fatigue failure in the mouth are two most important causes of fracture of denture base. Aim: This study evaluated the transverse deflection and transverse strength of four commercial brands of heat cure acrylic resin (Stellon, Acrylin-H, Trevalon and Trevalon-HI). Materials and Methods: An experimental design was adapted. Twenty-four rectangular strip specimens, six for each group, were prepared. Strips were finished on the edges and equally from the both the molded surfaces to make strips of specific dimensions. The tests were conducted mainly in accordance with the American Dental Association Specification no. 12/ISO: 1567-1981 (ISO: 6887-1986) for denture base polymer. The transverse deflection and transverse strength were measured by Instron testing machine. Intergroup differences were assessed using student "t" test. Results: The heat cure denture base material D (Trevalon "HI") had the minimum mean value of transverse deflection under different loads. Trevalon "HI" also had minimum value of mean transverse strength among different brands of acrylic resins. There was no statistically significant variation between Stellon, Acrylin-H and Trevalon, but variation was significantly higher with D (Trevalon "HI") vs. Stellon, Acrylin-H and Trevalon. Conclusion: The heat cure denture base material D (Trevalon "HI") was the strongest and C (Trevalon) was the weakest among all materials used in this study. The study showed that the deflection of various denture base resins (A to D) increases proportionately with the increase in load.

A simplified approach to fabrication of an ocular prosthesis: A case series.

The eye is a vital organ and an important component of facial expression. Loss of an eye has a crippling effect on the psychology of the patient. Enucleation of the eye is therefore normally followed by fabrication of an ocular prosthesis to improve esthetics. A less complex technique for fabrication of an ocular prosthesis is described in this report of two different cases.

Collarless metal ceramic restorations to obscure the umbrella effect.

Esthetics with porcelain fused to metal restoration in the anterior region can be adversely affected due to the inadequate teeth preparations and design of the prosthesis. We presented here a case report where esthetics was compromised due to darkening of the interdental papilla and marginal gingival and overcontoured restorations in relation to porcelain fused to metal restorations. Good esthetic results were obtained by using basic principles of tooth preparation and using collarless metal ceramic restorations.