Quintessence International, 02/1995

Predictable success of autogenous graft and implant reconstructions is critically dependent on preoperative alignment and prosthetic considerations planned by the surgeon and the restorative dentist in a team approach. In such cases the surgeon has an opportunity to place accurate bone grafts that allow implants to be secured in both the correct position and correct axis for good prosthetic restoration. With careful thought, the restorative dentist and surgeon can plan the location, shape, and volume of an implant graft reconstruction. Nine requirements for successful onlay grating with implants and five case reports illustrating the team approach are presented.

The acid-etch technique forbonding composite resins to enamel has revolutionized the practice of restorative dentistry. The ability of clinicians to bond restorative materials to enamel has fundamentally changed such diverse areas as cavity preparation, caries prevention, and esthetic treatment options. Although bonding of resin to dentin has proved to be a difficult challenge, ongoing advances are improving the reliability and predictability of dentinal adhesion. The purpose of this article is to provide a brief history of enamel and dentinal bonding, as well as an overview of the current state of the art.

This article describes a technique for fabrication of an implant radiologic-surgical stent, made of thermocurable clear resin, for the partially edentulous patient. Dual-curing composite resin is mixed with colored chalk powder and incorporated intot he stent to provide contract during computerized tomographic bone evaluation and to serve as an easily visible guide during fixture placement.

Talon cusp is a rate dental anomaly manifested as an accessory cusplike structure on the tooth crown. This article reports four cases of taln cusp that caused clinical problems related to appearance, occlusal interference, tooth displacement, caries, and tongue irritation. The cases presented were associated with other dental abnormalities, suggesting per se that genetic inheritance may be the causative factor. Clinical and radiographic characteristics of this developmental anomaly and modes of treatment are described.

Direct access preparation of a carious proximal surface is perhaps the most conservative approach to restoration. Phusical properties and handling characteristics of silver amalgam and of resin composite and lack of fluoride ion release made thee materials unsuitable for direct buccal-or lingual-access proximal restoration. Insufficient strengths and radiolucency of self hardening glass-ionomer cements preclude their use for Class II restorations. However, glass-ionomer silver-cermet cement and some resin-modified glass-ionomer materials are proving useful for non-stress bearing Class II restorations and may have applications in preventive dentistry. This article describes lateral-access Class II restoration with modified glass-ionomer cements. Emphasis is placed on careful handling of materials, maintenance of an ideal operative field, and conservation of tooth structure.

The aim of this in vitro study was to evaluate the marginal adaptation and seal of posterior composite resin restorations made with direct (three-sited multilayering) or indirect (extraoral inlay) techniques. The influence on the marginal quality of the cervical finishing design (butt or beveled) and residual enamel height (0.5, 1.0, and 1.5 mm up to the cementoenamel junction) was also evaluated. This trial was performed on sound, freshly extracted human molars. When residual enamel was less than 1.0 mm in height or 0.5 mm in thickness, indirect restoration resulted in superior marginal quality. For preparations with sufficient residual enamal height (greater than 1.0 mm), beveling of gingival margins appeared mandatory for good adaptation of direct restorations and beneficial to the adaptation of indirect restorations. Residual gingival enamal height and thickness demonstrated an influence on marginal quality only in indirect restorations with butt margins.

Recent developments in technology and restorative materials have renewed interest in air abrasion as a means of tooth preparation. The technique, also called kinetic cavity preparation, uses kinetic energy to remove tooth structure. The purpose of this investigation was to use scanning electron microscopy to compare the effects of this technique to those of high speed burs on extracted human teeth. Class V buccal preparations were made on five teeth with a No. 34 carbide bur used at 400,000 rpm and on 23 teeth with kinetic cavity preparation using differing combinations of aluminum oxide particle sizes and delivery pressures. Features of the specimens prepared at high speed included sharp line angles, chipping of the cavo-surface margin, and straited internal surfaces. Kinetic cavity preparations had rounded cavo-surface margins and internal line angles. The surfaces were microscopically rough and the dentinal tubules were occluded. There was little difference in appearance between specimens treated with various combinations of particle sizes and delivery pressures.

One of the factors that influences the overall fit of a Cerec restoration is the thickness of the optical powder. The objective of this study was to compare the measurement of the fit of glass inlays produced with the Cerec instrument after each preparation had been coated, in separate trials, with imaging powder applied with an aerosol; imaging powder applied with air from a dental unit; and a water-soluble paint applied with a brush. Ten inlay preparations were made in extracted teeth. Each preparation was coated with one of the three imaging media and an inlay was made. This was repeated until each preparation received each imaging surface. Each inlay was measured at eight different points by using an image analysis system interfaced to a stereoscopic measuring microscope. The inlays fabricated on the two powder surfaces were not significantly different, but the painted surfaces were found to result in a significantly better-fitting inlay

A review of the literature concerning the genesis of angular lesions of the teeth implicates occlusal stress as a critical component in the multifactorial etiology of these lesions. Clinical suggestions for the prevention and treatment of such defects are proposed.