Quintessence International, 04/1990

The primary objective of a provisional restoration is to promote gingival health before placement of the final restoration. A method for construction of a provisional fixed partial denture with improved marginal adaptation without the use of an indirect method is presented. A preformed shell of the provisional restoration must be fabricated from the diagnostic cast before any operative procedure attempted. The laboratory-made shells are relined intraorally to promote close adaptation to the finishing line of the preparation. A wash of cold-curing acrylic resin is applied to the margins while the bulk of the relining material is at the doughy stage. The technique provider superior results and reduced chairtime.

A supernumerary tooth that closely resembles the adjacent tooth is termed supplementary. A case to which a mandibular right first molar was replaced by a supplementary third premolar is presented. Recurrent caries under a crown on the first molar necessitated removal of the crown,so that only the roots remained. The roots were extracted, and the supernumerary tooth was moved orthodontically into a favorable arch position. A 6-month followup revealed no changes in the position of the tooth.

A clinical simulation was developed for the evaluation of amalgam restorations with defective margins. These restorations were defined as exhibiting marginal breakdown of various dimensions but having no clinically or radiographically detectable caries. Twenty-six restorations with marginal defects were evaluated by 124 dentists. A standardized patient description was presented, and the participant were requested to state their recommended treatment: no treatment, smooth or polish, or replace. Replacement decisions for amalgam restorations with marginal defects were highly variable. Treatment cost implications were significant, with a 625% difference between the high and low respondents. The appropriateness of most of the prescribed treatment needs to be evaluated in light of the Criteria developed as the recent International Symposium on Criteria for Placement and Replacement of Dental Restorations.

The purpose of this investigation was to compare the shear bond strengths of four dentinal adhesives. The shear bond strength was determined by testing specimens in the Instron universal testing machine at a crosshead speed of 0.5 mm/min. Scanning electron microscopic observations between × 10 and × 5000 magnifications demonstrated that the majority of the fracture patterns were either, in dentin or composite resin with Scotchbond 2 and near the adhesive interface with Tenure, Dentin Adhesit, and Gluma. A Tukey range statistic at P = .05 indicated no statistically significant difference between the bond strengths of Gluma and Dentin Adhesit; the bond strength of Tenure was significantly greater than that of Gluma or Dentin Adhesit, but less than that of Scotchbond 2; and the shear strength of Scotchbond 2 was significantly greater than that of Gluma, Dentin Adhesit, or Tenure.

The use of composite resin as a restorative material for Class I and II cavities is becoming more common. The marginal leakage at the proximal cervical margin of Class II composite resin restorations remains a major limitation to the widespread acceptance of this material. Although somewhat controversial, beveling of the cavosurface line angle has been suggested as a way to enhance the bond at the cervical margin that finishes on enamel. The acid-etched appearance of beveled and nonbeveled enamel at the proximal cervical margin of Class II cavities was studied under the scanning electron microscope. The results appear to support the efficacy of the beveling of this margin for Class II composite resin restorations.

his study evaluated the marginal sealing ability of three of the new generation of dentinal bonding agents. Class V preparations were placed at the cementoenamel junction of extracted human molars. The restored teeth were thermally stressed for 100 temperature cycles and placed in a dye solution for 24 hours. Microleakage was measured under a microscope at × 50 magnification. Under the experimental conditions, there was its significant difference in the performance of the bonding systems.

Defined total deflection of maxillary central incisors was ascertained in the orofacial, direction. The extent of bone atrophy resulting from marginal periodontitis was determined by radiography. Both values were compared with the Periotest value. A correlation and regression analysis demonstrated a significant relationship, such that the Periotest provided accurate information about bone atrophy.

Free-end removable partial dentures have long been considered a stepping stone between the patient's natural teeth and a complete denture. A direct, or Class I, lever allows stresses that will result in tissue resorption and eventual loss of the abutment teeth. An indirect, or back action, lever redirects the stresses to the long axis of the tooth. A design that utilizes these principles to prolong the life of the natural abutment teeth, the underlying tissue, and the removable partial denture is presented.

A case report involving a 50-year-old woman with the six mandibular anterior teeth remaining is used to demonstrate a combination restoration that utilizes a fixed partial denture as abutments for a removable partial denture. Traditional complete- coverage porcelain-fused-to-gold distal abutments are used with extracoronal precision attachments on the distal-most abutments. These are connected to each other using a modified dovetail, coronal, etched-metal lingual splint. A Class II bilateral removable partial denture is used to replace the missing posterior teeth. Four additional abutments are provided without compromise of esthetics, and reduction of healthy tooth structure is minimal.

The Universal Dental Anchor system is a group of precision connectors retained by pins cemented into the proximal surfaces of teeth. The goal of this system is to eliminate conventional teeth. preparation for retention of fixed prostheses. The type III single pin anchor was thought to have good potential when used on canines for short-span anterior fixed partial dentures. Indications and placement procedures are reviewed, and findings of a clinical pilot study are presented.

Reattachment techniques for tooth fragments present several advantages over restorations obtained with composite resin systems; better and long-lasting esthetics, improved function, a positive psychosocial response, and faster and less complicated procedures. The clinical cases are presented to describe a treatment modality that restores, through the attachment of the dental fragment, the esthetics and Function of anterior teeth in which fracture has invaded the biologic width. These procedures should be considered experimental surgery, not standard treatment.

The aim of every operator should always be to expose the patient to as close to zero radiation as possible. The amounts of radiation received form correctly taken dental radiographs are comparable to the background radiation received by the population. The average increase in exposure to the patient to radiation on an annual basis is not significant, and , without the information obtained from the radiographs, a complete dental assessment cannot be made. Provided that the operator is taking radiographs only after a clinical assessment has been made that they are required at that stage and provided that minimal doses and maximal radiation protection are ensured, the additional amount of radiation to the patient is low. Because of the probable advantages a the patient under these circumstances, the operator should not hesitate to take the necessary radiographs.