Quintessence International, 11/1991

Porcelain veneers have become a popular treatment modality in recent years. A common problem associated with these restorations is the inability of the dentist to reproduce the polychromatic appearance of a natural tooth with a porcelain veneer. It is the purpose of this article to describe several methods that may be used to transform a monochromatic porcelain veneer into a polychromatic restoration that approaches the beauty of a natural tooth.

After 14 years, 40 patients from an in vitro/in vivo study of 12 amalgam alloys were evaluated. All these patients had been attending private practitioners over the past 10 years, and the clinical evaluation revealed that 320 restorations were intact and 47 (12.8%) had been lost. The majority (75.0%) of the lost restorations were lost to crown placement or the replacement with another amalgam restoration. The six high-copper alloys exhibited bettter clinical performance, in both loss rate and fracture at the margins, than did traditional low-copper materials. Fracture at the margins was a better predictor of the loss of a restoration than were mechanical properties.

This case report describes a patient in whom orthodontic treatment and poor oral hygiene resulted in a severe mucogingival problem associated with a mandibular incisor tooth. Following mucogingival surgery, the esthetic and the oral hygiene maintenance problems were resolved. Orthodontic treatment carried out without periodontal consideration may, in some cases, jeopardize the final result.

A case is described in which excision of excess gingival tissue by conventional gingivectomy and simple restorative treatment wiht porcelain veneers produced a dramatic improvement in the patient's appearance with minimal sacrifice of sound tooth tissue.

Eight-five patients with a total of 103 resin-bonded bridges placed by practitioners at the University of Minnesota School of Dentistry between 1982 and 1989 were recalled for a clinical evaluation of their restorations. Tissue condition, patient satisfaction, bridge failures by location and by sex of patient, and average length of service for both successful and failed bridges were recorded. After an average service of 3.25 years, 12.6% of thef ixed partial dentures had debonded. Debondings occurred most frequently in the mandibular arch. Failures occurred more frequently in men than in women, and prostheses with more than two retainers had twice the probability for problems.

Presbyopia is inability of the eye to accommodate and provide clear images of near objects. It affects all dentists in middle age, when near point, the nearest point at which the eye can focus accurately, exceeds ideal working distance. Dentistry has unique visual demands and many older dentists have been shown to be working with less-than-optimal visual efficiency and comfort. This paper discusses methods for improving vision in the dental operatory and details a new design for eyeglasses suitable for the presbyopic dentist.

Two cases of maxillary anterior macrodontia, resulting from fusion and gemination, were treated orthodontically. Problems of esthetic and overjet were solved in the first patient by sectioning and extraction of a fused mesiodens, and in the second patient by treating toward an Angle Class III buccal occlusion.

The dentinal adhesive Scotchbond 2 was evaluated with the microfilled composite resin Silux in cervical and root caries lesions for up to 3 years. Clinical criteria evaluated included retention, marginal integrity, marginal discoloration, color match, anatomic form, recurrent caries, gingival response, and postoperative sensitivity. Overall, the adhesive demonstrated improved performance over earlier dentinal adhesive systems. Retention was greatest at 3 years when available enamel margins had been etched (93%) and when root caries lesions (97%) had been restored. Other criteria were reported as generally favorable. Early findings suggest that the level of development of sclerotic dentin may influence behavior of the adhesive. The greatest difficulty was noted in lesions presenting with heavy sclerotic dentin.

Voids in impressions made by five automixed addition silicone elastomers with and without intraoral delivery tips were investigated. The number of voids were counted at a predetermined site on 3 days. Hand-mixed impressions of the automixed materials were made for comparison. There was no statistically significant difference in the mean number of voids produced in each automixed silicone dispensed with the use of intraoral delivery tips and the number of voids produced without the use of the tips. However, there were significant differences in the number of voids among different materials. the rank order of the automixed silicone elastomers was fairly consistent, with Express producing the highest and Reprosil the lowest number of voids. Automixed silicone materials should only be prepared by automixing for optimal results.

To assess the biocompatibility of an adhesive system, standard Class V cavities were prepared in vivo in human premolars that were to be extracted for orthodontic purposes. Histologic observation revealed that the Gluma Bond System elicited slight to severe pulpal responses, altered odontoblastic layers, and inhibited dentinogenesis. These alterations were observed after in vivo periods of up to 120 days. In this experiment, the dentinal adhjesive was polymerized separately from the composite resin, a procedure not recommended by the manufacturer. This may explain the differences in the present results and those reported by the manufacturer.

Good mechanical retention between metal and resin or luting agent can be obtained by roughening the metal surface with lost crystal salts. The relationship of metal-resin bond strength to the shape and size of the crystals ws studied. The results indicated that cuboid crystal salts provided the best roughening among the tested crystal shapes (cube, irregular, spherical, and cuboid). There was no relationship between the tensile bond strength and the size of the crystals. Furthermore, the bending strength of metal coated with resin was improved by the roughening of the metal surface.