International Journal of Periodontics & Restorative Dentistry, 03/1992

Eighty-six edentulous patients provided with Brånemark implants were randomly selected for fixed prostheses with modified framework designs. This study describes alternative laboratory techniques in which premachined titanium components are welded together to form the framework. Clinical experience, following the patients for 1 year after placement, indicates that it is a predictable technique with a similar pattern of complications as experienced by patients with cast frameworks supported by implants. The prostheses are considered to be slightly more bulky than cast frameworks, but seem to have, on a clinical level, a better fit to the implants.

Guided tissue regeneration, the principle of using membranes to exclude epithelial tissue during wound healing, thus enhancing periodontal regeneration, is an exciting addition to the implant armamentarium. However, additional clinical review of the results, advantages, and disadvantages of guided tissue regeneration is necessary before the procedure can be recommended for routine use. To this end, the author reports three representative cases in which membranes were used to encourage healing and discusses the results and problems.

A number of materials are available to protect the pulp from postoperative sensitivity. The effect of a calcium hydroxide liner and a dentinal desensitizing agent (potassium oxalate) on crown retention was investigated. Gold crowns were cemented on standardized crown preparations with zinc phosphate cement, glass-ionomer cement, or one of two resin cements. A tensile force was applied until separation occurred. The mean applied force at rupture varied greatly among the groups, indicating that the pulpal protection agent may have a distinct effect on the retention of cast restorations. In addition, other clinical factors, such as angle of convergence, crown height, and total surface area of the tooth should be considered.

This paper demonstrates that an intact extraction socket is not necessary for the successful integration of a titanium implant fixture. Several case reports are used to describe the immediate placement of fixtures into compromised sockets, some in conjunction with bone grafting and/or guided tissue regeneration techniques to enhance the surgical result. Advantages of immediate implant placement are threefold: (1) treatment time is significantly reduced; (2) ridge contour can be preserved; and (3) it is possible to place the fixture in a more ideal axial position, thus enhancing fabrication, esthetics, and biomechanics of the subsequent restoration.

This study investigated the effect of citric acid application on periodontally involved root surfaces. Forty periodontally involved teeth were randomly divided into four groups of ten teeth each: no treatment, citric acid treatment, root planing alone, and root planing in conjunction with citric acid treatment. Ten nondiseased, untreated teeth served as controls. After treatment, each tooth was split along its long axis; half was examined under light microscopy and half under scanning electron microscopy (part II of the paper). Light microscopy revealed that the effects obtained by scaling and root planing were not altered after citric acid application. Moreover, the cementum layer was not entirely removed without careful and thorough planing of the root surface. Citric acid application alone had no effect on the diseased root surface. Citric acid did not penetrate the dentinal tubules, nor did it alter the collagen content of the roots obtained by scaling and root planing.

This study evaluated the ability of collagen membranes to act as biodegradable barriers that interfere with colonization of the root surface by gingival cells and allow selective repopulation of the denuded root surface by periodontal ligament-derived tissue. Over a 3-year period, experimental and control surgical procedures were performed on canine teeth in six beagle dogs and on premolars in three beagle dogs. Results showed that the membranes partially prevented apical migration of epithelium during healing. Regeneration of new cementum, alveolar bone, and periodontal ligament-like tissue was found in the studied premolars but notably absent on the canines.