Quintessence International, 02/1994

Crown-lengthening procedures can provide solutions for specific periodontal, restorative, or esthetic problems. Frequently, there is a distinct relationship between difficulties arising from periodontal anomalies and clinical problems associated with restorative or esthetic dentistry. The aim of crown lengthening, irrespective of the m ethod employed, is to provide a healthy and stable dentogingival complex. To achieve this goal, it seems appropriate to take into consideration the dimensions of the biologic width. The indications and treatment modalities for lengthening clinical crowns are discussed.

A maxillary central incisor fractured, invading the biologic width. The biologic width was surgically restored, and in the same session the fragment was reattached to the tooth remnant with a new dentinal adhesive system. Short-term results indicate that esthetics, function, and oral health have been maintained.

The simultaneous curing of unpolymerized composite resin and inactivated light-curing glass-ionomer cement appears to offer a number of clinical improvements to the laminated gl ass-ionomer cement-composite resin restoration. The observation that composite resin cures before the glass-ionomer cement suggests that the polymerization shrinkage of the resin may be taken up by the uncured glass-ionomer cement, reducing the internal stress of the restoration. A procedure is described for the placement of this type of laminate restoration that reduces both technique sensitivity and placement time, by eliminating a number of the steps required for a conventional sandwich restoration. The apparent clinical success of this technique indicates the need for laboratory testing to evaluate the potential of this procedure.

The long-term performance of two chemically activated composite resins was compared to that of one silicate cement. Bulk and cavosurface marginal discoloration was evaluated with both an indirect photographic method and the direct US Public Health Service evaluation system. The results confirmed that composite resins had superior performance but higher secondary caries incidence than did silicate cements. The macrofilled composite resins showed better clinical performance than the microfilled restorations, as well as similar incidences of bulk and marginal discoloration. The agreement between the scores obtai ned with the direct evaluation criteria and those resulting from the indirect evaluation method was relatively poor. The indirect scores were usually the same or poorer than the direct clinical scores. The results indicated that the clinical evaluation may be the least sensitive of the two methods. The discrepancy in the scorings may, on the other hand, signify that the indirect photographic method records reflectance spectra that are not n ormally obtained in vivo.

This is a report of a case in which the techniques of endodontic retrofill and guided tissue regeneration were used together to treat a perforation of the mesiofacial root of a maxillary left first molar (a strip perforation). After full-thickness flap reflection, the root received a retrograde filling and a large fenestration defect was surgically created to allow access to the furcal (distal) surface of the mesiofacial root. The roots were treated with tetracycline, the defect was filled with freeze-dried, demineralized, irradiated human cadaver bone, and the access fenestration was covered with a piece of barrier membrane. Healing was uneventful and the defect showed 100% bone fill at the time of reentry to retrieve the membrane 7 months after the initial surgery. Fifteen months after surgery the area appears clinically and radiographically healthy and the tooth has been employed as an abutment for a fixed partial den ture.

The cases of two patients with large cystlike periapical lesions are presented. The lesions formed as a result of trauma to the associated teeth. Following conservative nonsurgical endodontic treatment, there was complete resolution of the lesions. These results suggest that the largeness of a periapical lesion does not mandate its surgical removal and that even cystlike periapical lesions heal following conservative endodontic therapy.

A variety of philosophies and techniques for the prescription of esthetically and functionally acceptable complete dentures are reviewed. Guidelines for the use of anatomic landmarks are discussed in addition to functional determinants of tooth position. The value of pre-extraction records is discussed and suggestions are made as to useful clinical aides to ore appropriate prescription of acceptable dentures.

The longevity of resin-bonded prostheses made of a high-gold alloy and bonded with Super-Bond C&B (C&B Metabond) were tested clinically. Minimal preparation and large surface area of retainer coverage were used. The inner surfaces of the retainers were air abraded with aluminum oxide and heat treated in an oven at 400 degrees C to get an oxidized layer for bonding. The results of the adhesive technique were unsatisfactory compared with studies with resin-bonded prostheses using conventional mechanical retention techniques and nonadhesive resin cements. All fractures were at the resin-metal interface. Early debonds occurred; seven of 13 prostheses were detached after 11 months. The median survival time was only 9 months. The adhesion of resin-bonded prostheses must still be based on mechanical retention between cement and metal, because a way of attaining good durability of the bonding joints to water with Super-Bond is yet to be found.

The precancerous nature of the most common of chronic and mucosal lesions, leukoplakia, is much better understood now than at any time since it was first brought to professional attention by Sir James Paget 143 years ago. Clinical research from the past decade now allows confident identification of high-risk features of oral leukoplakias and of those persons affected by them. This paper summarizes current understanding of this important disease and provides practical suggestions for appropriate management and classification of its various subtypes or phases.

Three cases of regional odontodysplasia are reported, and the clinical, radiographic, and histopathologic features of the disease in these cases are compared with those of cases previously reported in the literature.