Reduced dental plaque accumulation on composite gold alloy margins.

Restoration of tooth surfaces with materials that inhibit formation of heavy bacterial plaque accumulations could be important in the treatment of patients with existing oral disease or in reducing the likelihood for periodontal disease. Captek is a dental gold composite material used to produce copings for ceramometal restorations that has been reported to inhibit plaque accumulation. In this study, the oral bacteria of nine periodontally healthy subjects with a total of 42 gold composite copings were sampled. Contralateral teeth with normal tooth surfaces were also sampled as controls. The quantitative presence of forty bacteria was determined in each sample by DNA:DNA hybridization. The results indicated that the porcelain/gold composite alloy coping surfaces had significantly fewer bacteria than the control normal tooth surfaces (71% reduction). The percentage composition, however, did not differ significantly between surfaces.

Vital tooth esthetics in Captek restorations.

Captek crowns and bridges employ optical effects that simulate vital tooth esthetics. The intensive red color of the blood in the vital pulp plays an important role in natural tooth appearance. This role is often ignored in restoration construction and results in a dead-looking restored tooth. To achieve optimal tooth esthetics, it is essential to mimic these often overlooked esthetic qualities.

Reinforced porcelain system. Concepts and techniques.

The RPS approach to ceramometal restorations provides guidelines for the design of metal interstructure for crowns and pontics and for the desired qualities of the ceramometal interface. The metal design increases porcelain fracture resistance to impact and pressure and creates a ceramometal mutual reinforcement of the whole restoration. A secure bond and porcelain protection at the interface can be achieved through intermediate zone materials.

Reinforced porcelain system: a new concept in ceramometal restorations.

The RPS concept and technique for the fabrication of ceramometal fixed restorations includes a new design for the metal structures of crowns and pontics and intermediate zone materials that function between the metal and the porcelain. The RPS metal design for anterior and posterior crowns consists of thimble copings with shelves, belts, and blades. These metal extensions enhance procelain fracture resistance to impact and shearing forces. The mutual reinforcement of the porcelain and the interconnecting metal bar structure of RPS pontics produces durable restorations. The RPS intermediate zone materials secure the bond between porcelain and all types of ceramic alloys and produce stress relief zones at the interface.

Vascular responses in the human periodontal ligament and alveolar bone detected by photoelectric plethysmography: the effect of force application to the tooth.

A modification of the technique of photoelectric plethysmography has been developed to monitor changes in the microcirculation of the human periodontal ligament and adjacent alveolar bone, whereby detection is made of light reflected from or transmitted through a tissue during alterations in blood volume, flow or distribution. Light is conducted to and from the periodontal tissues via miniature fiberoptics placed within the root canals of endodontically treated teeth, or illuminated through the external surface of the gingiva towards the root. Circulatory activity was monitored both with the teeth at rest and under forces up to 480 gm. Horizontal and axial forces were found to produce a decrease in blood volume in the area of the periodontal tissue under compression. In an area under tension, an initial increase in blood volume was followed by a decrease as the magnitude of force rose above the critical 90 to 180 gm level. The pulse volume, however, was increased during both phases. Analysis of the biphasic and pulse volume changes suggests that autoregulation of blood vessel tone occurs in the periodontal tissues as a result of alteration in extravascular tissue pressure when the root is moved relative to the alveolus. It is proposed that this autoregulatory mechanism may play a role in alveolar bone metabolism by producing alteration in local tissue oxygen tension.