Quintessence International, 01/1992

This paper presents a technique for restoring maxillary posterior teeth with a combined composite resin and amalgam restoration when the preparation extends buccally into an esthetically critical area. This technique has two major advantages over traditional combined restorations: it requires only one clinical appointment, and it provides an esthetically acceptable result while maintaining the advantages of an amalgam restoration. A clinical assessment of 12 of these restorations, in vivo for 0.8 to 6.4 years, is presented. All but one restoration received a score of excellent or acceptable.

This paper presents a case in which tooth exfoliation followed rubber dam abuse. A 40-year-old patient was referred to the prosthodontic clinic with complaints of mobility and discomfort in tooth 44, which had received an amalgam restoration. While this tooth was scaled, a piece of rubber dam appeared in the buccal sulcus. Removal of the rubber piece was followed by thorough scaling and tooth splinting. Tooth deterioration continued, and concern for the adjacent teeth necessitated extraction of tooth 44. To avoid such undesirable consequences, the integrit y of the dam should be verified on its removal.

To assess if the association of epinephrine with local anesthesia involves cardiovascular risks, 14 patients undergoing treatment were observed. Systolic and diastolic blood pressures and mean and maximal heart rates were analyzed. The comparison of basal and postanesthetic periods revealed a trend (nonsignificant) toward an increase in systolic blood pressure and a small, statistically significant increase in diastolic blood pressure; the heart rate increased in only a few patients, and never by more than 10 beats/min. The whole group showed a statistically significant reduction in mean and maximal heart rates from the basal period to an end-session period. Thus, in these patients, the given epinephrine doses resulted in negligible changes in heart rate and blood pressure. The reduction in heart rates at the end of treatment underlines the important role of the autonomic nervous system in the modulation of the cardiovascular response during dental sessions

The In-Ceram technique uses alumina ceramics and glass in a two-step firing procedure to create a high-strength core material for single-tooth restorations as well as small fixed partial dentures. Fine-grain alumina particles are sintered to form a porous substructure, which is infiltrated with molten glass. The combination of these two processes gives the material its outstanding properties. The sintering process is almost without shrinkage, providing an excellent fit, while the glass infiltration leaves practically no porosities, resulting in high strength.

Intentional tooth replantation is a last-resort procedure, recommended only when all other techniques, short of tooth ext raction, have been exhausted or are impractical. Although most endodontic textbooks describe the procedure, and many reports of intentional replantation have appeared in the dental literature, none have reported use of the technique to retain a removable partial denture abutment tooth. This article presents such a case and the rationale for the decision to intentionally replant. Eighteen-month follow-up clinical and radiographic results are presented.

An in vitro study was undertaken to evaluate the ability of a dentin-enamel bonding system to bond to wet, as well as to dry, dentinal substrate. The All-Etch/All-Bond system was used to bond to wet and dry dentin using 10% and 37% phosphoric acid surface conditioning. The wet dentinal surfaces exhibited significantly higher bond strengths than did the dry surfaces. It is suggested that, because of the unique behavior of the resin-primer mixture, the dentinal surface is adapted to much more thoroughly and intimately when the surface is wet.

The first paper in this series presented a categorization of dentinal adhesive systems that was organized roughly according to chronology, chemistry, and shear bond strength values. Category I dentinal adhesives demonstrate the lowest shear bond strength values, approximately 5 to 7 MPa. Category II dentinal adhesives, including experimental ferric and aluminum oxalate rpetreatments and two commercial products, demonstrate shear bond strength values between 8 and 14 MPa. This second category of dentinal adhesives is the subject of this paper. An attempt is made to draw a parallel between the penetrative ability of the adhesive (the wettability of the dentinal substrate) and the efficacy of the adhesive bond as determined by shear bond strength values. Category III dentinal adhesives will be discussed in another paper.

Resin cements, which have been shown to adhere to various metal alloys, were investigated as possible repair adhesives for dental amalgam. Test bars of repaired amalgam, formed by condensing new alloy against previously set alloy with or without the use of adhesive resins, were subjected to three-point bending measurements of transverse fracture strength. The results indicated that application of adhesive resin did not improve the breaking strength of the repaired specimens from that of specimens prepared without the use of such resins. The breaking strength of all repaired specimens was approximately 15% of the transverse fracture strength of the original intact amalgam bars. Scanning electron microscopy revealed that there was an intermixing of fresh amalgam and unset interfacial resin, which led to mechanical bonding of these materials, but there was no evidence of adhesion of the resin to the previously set amalgam.

Formalin treatment of dentin, prior to burnishing demineralization, results in a tufted collagen surface that may optimize bonding of hydroxyethyl methacrylate dentinal bonding agents. The purpose of this study was to determine if there is a clinically acceptable formalin treatment time that will yield a deeply tufted collagen surface. The exposed dentin of periodontally healthy and periodontally diseased human teeth was treated with formalin for various treatment times before burnishing demineralization with citric acid. Photographs of the specimens revealed that there was a statistically significant difference in the number of tufted surfaces found in the healthy group, as a whole, and the number found in the diseased group. No statistically significant difference was found among fixation times within either tooth group. It was concluded that 2 minutes of fixation was sufficient to produce a tufted fibrillar surface.

Panavia, a composite resin luting agent containing phosphate monomers, bonds chemically to air-abraded base metal alloys and is particularly suited for cementing resin-bonded retainers. Another adhesive methodology (Silicoater system) incorporates a pyrolytically applied silica layer to metal substrates to promote bonding of a resin adhesive. The object of this study was to compare prosthodontic adhesive systems that incorporated the Silicoater system and/or Panavia. The results showed that the surface treatment that provided significantly higher shear bond strengths was the Silicoater system and a layer of unfilled resin. A second test evaluated use of Panavia as a metal opaquing material beneath laboratory light-curing resins. Results showed that Panavia Opaque materi al was displaced peripherally during placement of overlying laboratory composite resin veneers. This resulted in an uneven intermediate layer of Panavia.