A modified matrix technique for the application of restorative materials on the facial surfaces of teeth.

A Tofflemire matrix is modified and is secured in place with the help of Super Floss and unfilled light-activated resin or light-activated impression material. The matrix prevents excess cementing medium escaping in the gingival area, providing excellent isolation. The technique is simple and provides good esthetics while minimizing lengthy and traumatic finishing procedures.

A comparison of the shear strength of chemically versus electrolytically etched metal retainers.

The recent popularity of acid-etched, resin-bonded retainers (RBR) has initiated improvements in design, technique, and etching. This study compared the shear strength of chemically etched Biobond retainers with electrolytically etched retainers bonded to enamel using identical cement. Shear fracture loads were recorded using Instrom testing for all specimens. The mean fracture load for the electrolytically etched castings was greater than that of the chemically etched castings. Electrolytically etched specimens also recorded the greatest and the least fracture load values. These results indicated that, while there were significant differences between the two groups with greater shear strength values for electrolytic etching, there was also more variation in shear fracture load with electrolytic etching.

Amalgam onlay restoration.

This article discusses a conservative class II amalgam cavity preparation that is similar to a cast onlay preparation except for the absence of the lingual and facial bevels. When extensive decay is removed and undermined cusps are present, onlays from amalgam support tooth structure and prevent fractures. To achieve this, cusps must be reduced to provide for a sufficient bulk of amalgam. The described technique can be applied to class II cavity preparations with weak cusps, class I cavity preparations when the remaining cavity provides adequate retention, and to endodontically treated teeth for which finances do not permit cast restorations.

A new chemical method for etching metal frameworks of the acid-etched prosthesis.

Alloys containing beryllium, silicon, boron, and all nickel base alloys are etched well by the method described, with the exception of Fore alloy manufactured by the Unitek Corp. Alloys containing chrome and cobalt cannot be etched with Met-Etch gel. The advantages of using this method of chemical etching are (1) this conservative procedure can be performed in two clinical sessions, (2) the etching of the framework can be effectively controlled by the dentist or the laboratory technician, and (3) if the metal framework is dislodged it can be cleaned, etched, and reattached during the same appointment.

Protrusive positioners.

Techniques were described for fabricating maxillary and mandibular protrusive positioners for treatment of disk-condyle derangements. Treatment time with the splints varies from 4 to 12 months depending on the age of the patient, the degree of existing symptoms, and patient motivation. At the end of the treatment period and after removal of the splints, the patient may have (1) no pain or internal derangement, (2) no pain but internal derangement with or without reduction, or (3) pain and internal derangement with or without reduction. If dental treatment is required, patients in the first two categories can be treated at a physiologically acceptable treatment position with existing treatment modalities. For patients in the third category, definitive, irreversible stabilization should be reevaluated. For these patients a mandibular cast splint can be changed to an interim splint by replacing the self-polymerizing resin with Isosit (Ivoclar-Vivadent, Schaan, Liechtenstein) or heat-processed acrylic resin.

A shear test evaluation of a new, modified, unfilled resin.

A shear test was conducted under simulated oral environmental conditions to examine the retention of a new, commercially available modified unfilled resin in comparison with a conventional unfilled resin provided by the same manufacturer. Within the experimental limits of this study no difference was observed between the retention of the conventional and the modified unfilled resins to enamel specimens. However, for dentin specimens the modified resin was clearly superior to the conventional resin, which gave essentially zero retention. With the recommended procedure, the retention of the modified resin to dentin was 13% of that for the retention of either resin to enamel. It was also observed microscopically that the new resin demonstrated good wetting ability of the dentinal surface. The retention of the two resins to dentin with various surface treatments was determined. The recommended surface preparation procedures of cleaning the dentin surface with hydrogen peroxide followed by a water rinse gave equivalent, if not superior, results to a 1-minute etch with phosphoric acid or citric acid followed by a water rinse.

Provisional restorations for altered occlusions.

A method for fabricating provisional restorations with specific criteria has been outlined and offers the following advantages: Altered occlusion can be restored. Select steps can be delegated to auxiliary personnel. Commercial laboratory fees are eliminated. It is inexpensive. The restorations are durable and esthetic. Restorations are readily modified intraorally. This flexible procedure is used for short or long spans, and/or for segmented treatment. Casts of acceptable anterior provisional restorations can provide a template for developing anterior guidance in the final restorations.

Distribution of ABO blood group substances in various types of oral lichen planus.

Formalin-fixed, paraffin-embedded tissue sections of fifty oral lichen planus lesions including hypertrophic, atrophic and erosive types, were examined by an immunofluorescent technique for the presence of the ABO blood group antigens. The antigen activity in lichen planus lesions was compared with the reactivity of normal human and Rhesus monkey oral mucosa as controls, and the reactivity of adjacent normal epithelium in the same specimen. A difference in the distribution of the blood group substances was observed in the three different types of oral lichen planus. The hypertrophic showed the strongest staining reaction approaching that of the normal, whereas a decrease in quantity of blood group substances was seen in the atrophic, and a tendency to complete loss in the erosive type. There was a marked tendency for loss of staining to be greater in lesions from older patients; this could be related to the greater frequency of atrophic and erosive lesions in the elderly.