Quintessence International, 10/2002

Gingival recession defects have traditionally been treated with various grafting procedures. Recently, guided tissue regeneration with collagen membranes has shown promising results. This article reviews the rationale, indications, contraindications, and clinical methods for the use of bioabsorbable collagen membrane barriers. Several properties make collagen membranes attractive candidates for use as barriers in guided tissue regeneration-based root coverage procedures. These include the inhibition of epithelial migration and promotion of new connective tissue attachment; the ability to aggregate platelets, thereby facilitating wound stabilization and maturation; the promotion of cellular migration and wound closure; the elimination of the need for reentry surgery; and the ability to augment tissue thickness. Cases are presented to illustrate the surgical principles and techniques.

Objective: It would be advantageous to be able to use computer-aided design and manufacturing to fabricate a restoration that can be layered with a conventional porcelain veneer in the occlusal region, thus optimizing esthetics, function, and strength. This case study reports the laboratory technique and the clinical performance of 38 partial crowns fabricated with computer technology and veneered with porcelain. Method and materials: Twenty-one mandibular and 17 maxillary molars in 27 patients were prepared for partial crowns. The occlusal surfaces were lowered (1.5 to 2.0 mm), deep shoulders (1.5 mm) were prepared around the functional cusps, and 1.0-mm-deep shoulders were prepared in the proximal gingival regions. The nonfunctional cusps were prepared with an occlusal shoulder at approximately a right angle with the axial surfaces of the seat. In the computer-aided design procedure, the occlusal table was reduced to 1.4 mm above the preparation surface. The marginal ridge points, the marginal ridge line, the equator line, and the fissure line heights were adjusted accordingly. Results: The lowest occlusal table thickness was 1.1 mm in six partial crowns, 1.2 mm in 26 partial crowns, and 1.3 mm in six partial crowns. The lowest occlusal table thickness of the porcelain veneers varied between 0.4 and 0.6 mm. The total occlusal table thickness thus was 1.5 mm or more. Clinically, no fractures occurred during an observation period varying between 1 and 4 years after placement. Conclusion: Computer-aided design and manufacturing technology is also convenient for partial crown preparation design with shoulder finish lines.

Objective: The composition of the salivary interface (pellicle) between dental restorations and oral mucosa may be critical to the biocompatibility of the restoration. The purpose of this study was to examine the molecular composition of the salivary pellicle on nickel-chromium alloy in vivo. Method and materials: The molecular components of nickel-chromium pellicle was examined with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analyses. Results: Only limited numbers of salivary proteins were found to participate in the formation of nickel-chromium pellicle in vivo. Salivary amylase and secretory immunoglobulin A were among the proteins identified in the pellicle. Conclusion: In vivo, nickel-chromium pellicle consists of selectively adsorbed salivary proteins. Because both salivary amylase and secretory immunoglobulin A are antimicrobial proteins, it is possible that they play a role in modulating the microbial flora on the nickel-chromium prosthesis.

Advances in the field of restorative materials allow a lost tooth to be replaced by artificial tooth structure that is virtually indiscernible from the original. However, in fixed partial dentures the standards for the pontic area and the adjacent soft tissue in the maxillary anterior region have increased in particular. The pontic design in this region is primarily influenced by esthetic and phonetic considerations. Local defects of the alveolar ridge often complicate restorative measures. Treatment methods proposed to solve this problem involve modification of the pontic design and pretreatment of the recipient site for the pontic. This article reviews the different clinical and technical options that are available for designing esthetic and functional pontics for the anterior region.

A removable partial denture should restore function, phonetics, and esthetics. To assist the clinician in providing a restoration that is as esthetic as possible, despite the limitations of the conventional removable partial denture, this review collates the recommendations scattered among the literature. The review describes the steps involved in providing an esthetic restoration, including diagnosis and treatment planning; surveying; mouth preparation; framework and clasp alloys; clasps; rests; major connectors; minor connectors; prosthetic teeth; and denture base resin and flanges. The esthetic challenges of the Kennedy Class IV removable partial denture are also discussed.

Objective: The aims of this study were to establish the cephalometric norms for Turkish adults by means of the Holdaway analysis and to investigate the cephalometric differences between Turkish women and men. Method and materials: The study materials consisted of 100 cephalometric head films taken at the natural head position. The 50 men and 50 women who volunteered for the study had to be older than 18 years and had to have parents of Turkish origin, acceptable facial structure, ideal dental occlusion, no visual or hearing disorders, and all the teeth present in their mouths except the third molar teeth. The selected subjects had not undergone orthodontic treatment or orthognathic surgery, had no burns, injuries, or scar tissue in the head and neck regions, and had no breathing or swallowing disorder. The measurements of hard and soft tissues were carried out on lateral cephalometric radiographs taken at natural head position. The measurements were evaluated with a computer software program. The effects of sex on the measurements were investigated by means of Student's t test. Results: The differences between men and women in nose prominence, basic upper lip thickness, upper lip thickness, inferior sulcus to the H line, and soft tissue chin thickness were statistically significant. Conclusion: The upper lip, nose, and chin are more protruded in men than they are in women.

Objective: The aim of this study was to determine the microleakage of current-generation dentin bonding systems in Class II resin composite restorations. Method and materials: Class II (occlusodistal or occlusomesial) cavity preparations with a gingival margin 2 mm apical to the cementoenamel junction were prepared on 70 noncarious, extracted human premolar teeth. Teeth were randomly divided into five groups and treated with different-generation bonding systems (Optibond FL, Gluma One Bond, Clearfil SE Bond, acid etching plus Clearfil SE Bond, and Prompt-L-Pop). All cavities were restored in a posterior resin composite and subjected to 200 thermocycles (at 5°C to 55°C; 30-second dwell time). After immersion in 0.5% basic fuchsin dye for 24 hours, the teeth were sectioned longitudinally and evaluated for dye penetration using a binocular stereomicroscope. Results: There was no statistically significant differences among bonding systems in the degree of microleakage in the occlusal walls. For gingival walls, statistically significant differences were found only between the Clearfil SE Bond and Prompt-L-Pop groups and the Clearfil SE Bond with acid etching and Prompt-L-Pop groups. The greatest microleakage was observed in Prompt-L-Pop specimens. Conclusion: Most of the tested dentin bonding systems were able to eliminate microleakage completely in the occlusal walls, but some systems exhibited statistically significant differences in leakage in the gingival walls.

Objective: The aim of this in vitro study was to evaluate the tensile bond strength values between polyacid-modified resin composite ("compomer") and resin composite materials under different conditions. Method and materials: There were five experimental groups in the study. In group A, resin composite was placed directly on polyacid-modified resin composite surfaces. In group B, bonding agent was applied to polyacid-modified resin composite surfaces and then resin composite was placed on the compomer. In group C, compomer specimens were stored for 1 week and then resin composite was placed directly on these aged compomers. In group D, compomer specimens were again stored for 1 week, and then the bonding agent and resin composite were applied to the compomer surfaces. In group E, the surfaces of aged (1 week) compomers were roughened before the bonding agent was applied and the resin composite was placed on the prepared surfaces. A statistical analysis of the results was made with the Kruskal-Wallis test method. Results: The mean tensile strength values of the groups were as follows: group A = 12.84 MPa; group B = 15.03 MPa; group C = 10.60 MPa; group D = 11.56 MPa; group E = 24.87 MPa. There were statistically significant differences between groups E and A; groups E and C; groups E and D; and groups C and B. Conclusion: Mechanical roughening of a polyacid-modified resin composite surface was found to be the most effective factor in increasing the tensile bond strength between an aged compomer and a resin composite.

Masseteric hypertrophy is a benign increase in the size of the masseter muscle, secondary to muscle hypertrophy. It produces facial asymmetry and is important in the differential diagnosis of other entities. The aim of this article is to report a case of unilateral masseteric muscle hypertrophy. The characteristics and diagnostic features of such alterations and options for treatment will be presented.