Quintessence International, 12/1991

This paper draws attention to the important role of supragingival tooth structure in providing resistance to displacing forces, particularly transverse forces, on crown posts. Evaluation of the success rate of crown posts has indicated that remaining tooth structure and post space configuration should be taken into consideration during treatment planning. To facilitate the recording of, treatment planning for, and communication about the restoration of pulpless teeth, a simple classification of the remaining tooth structure is proposed.

A patient whose teeth had been severely stained by improper use of tetracycline was treated through a direct system of facial veneering. The technique associates the use of a light-activating glass-ionomer cement with two kinds of light-activating composite resin. Satisfactory esthetics were obtained immediately.

A reconstruction technique is presented for endodontically treated teeth in which a minimally invasive procedure is desired. A resin-bonded, laboratory-fabricated, heat-and press ure-cured composite resin onlay was used to achieve tooth support as well as esthetic results.

This paper presents a relatively simple method of repairing a large porcelain fracture in aporcelain-fused-to-metal crown that is part of a multi-unit fixed partial denture. The technique involves fitting a modified porcelain-fused-to-metal crown over the original damaged crown following some preparation of the original crown. This technique is of special value when a permanently cemented multi-unit restoration is involved, eliminating the need to replace the entire restoration and providing a durable estethic result.

The aim of this study ws to evaluate the permeability of the disposable, nonsterile gloves used in dental practice. A visual inspection and a water-filling test were carried out on seven different brands of gloves. Only five of the seven makes analyzed showed a value of pinch marks statistically not different from 2% (the limit recommended by the American Society for Testing and Materials). Analysis of the gloves with holes revealed that only four makes showed a value statistically not different from 2%. Finally, only three of the seven makes analyzed had a number of defects statistically not different from 2%. It may therefore be stated that the average quality level currently available should be improved to guarantee a safer and more effective protection against oral pathogens in dental practice.

For economic reasons, nickel alloys are in widespread use in dentistry. However, allergic reactions have been observed in nickel-sensitive patients. In this study, absorption of nickel in the serum, liver, kidney and oral mucosa of guinea pigs was examined. Guinea pigs experimentally sensitized to nickel showed significantly higher levels of nickel in serum than did control animals. Levels of nickel in experimental and control animals were found to increase over time.

Three categories of dentinal adhesive are proposed: category I includes adhesives with shear bond strength values between 5 and 7 MPa; category II includes dentinal adhesives with shear bond strengths between 8 and 14 MPa; and category III includes adhesives with shear bond strength values up to 20 MPa. In part I of this article, photomicrographs of the dentinal smear layer and three category I first-generation dentin-adhesive interfaces are presented. The photomicrographs show that the wetting and penetration of the first-generation dentinal adhesives were not adequate to produce high shear bond strengths. When the category I adhesives were tested for shear bond strength, failures occurred at the interface or in the resin adhesive. Future articles will explain wetting and adhesive performance of category II and III adhesives.

A 4-META-containing adhesive was evaluated for its ability to bond a composite resin and two types of amalgam to dentin. One group of composite resin was tested after 24 hours and another group after 24 hours of thermocycling. Shear bond strengths were: composite resin at 24 hours = 22.38 MPa; thermocycled composite resin = 20.86 MPa; spherical alloy = 3.38 MPa; admixed alloy = 3.84 MPa. Microleakage was evaluated after the 4-META adhesive was appli ed to cavity preparations and compared to that of a group treated with a cavity varnish. There was statistically significantly less microleakage in the 4-META group at both the occlusal and gingival margins

The purpose of this study was to evaluate the abrasive effect on toothbrush bristles caused by three brands of commercially distributed dentifrices: Colgate regular favor, Crest tartar-control formula, and Caffree gel. New brushes and brushes tested in distilled water served as controls. Scanning electron micrographs were taken of all test samples, randomly labeled, then presented to independent evaluators. Each bristle evaluated was assigned to one of seven wear categories adapted from previous studies. Crest and caffree produced the most bristle wear and were not significantly different from each other. Colgate and water resulted in less wear, and new brushes the least wear. These results demonstrate that the effective life of a toothbrush will vary with the type of dentifrice used.

The conteomporary literature concerning the etiology, frequency, and classification of supernumerary teeth, specifically molars, is reviewed in this article. Also, methods for their early detection, as well as the prognosis and treatment of supernumerary molars, are discussed. Eight cases at the University of Athens and 105 others obtained from the literature were subjected to statistical analysis to examine sexual dimorphism and the position, impactions, and bilateral presence of supernumerary molars. Supernumerary molars occurred more frequently in the maxilla (79.7%), often were impacted (88.7%), and were found bilaterally 23.9% of the time. No great difference was found between the sexes in the frequency of supernumerary molars.

Acute exacerbation of symptoms, or flare-up, after the debridement of the root canals and provisional restoration is a well-known postoperative complication of endodontic treatment. In this clinical study, various types of intracanal medications were compared for their ability to decrease interappointment flare-ups. The result showed that use of intracanal medicaments containing anti-inflammatory agents in combination with the administration of prophylactic systematic antibiotics was the most effective mthod of controlling interappointment flare-ups.