Quintessence International, 07/1993

For 5,000 years innovative researchers, often anonymously, have been providing dentists and their antecedents with a rich inheritance of information, techniques, and materials. The giants of dental research of the past can still serve as role models today. This paper presents a history of clinical research and relates past work to current and future trends. In the last few decades, both technical innovation and oral biology and prevention have been progressing at an accelerated rate to provide a steady influx of new answers to dental practitioners and to elicit new questions from the next generation of dental investigators.

This paper presents a review of the literature and clinical observations concerning the long-term professional care of all dental patients. Gingivitis, ubiquitous in the adult population, is often without significant consequences to the dentition; however, gingivitis may develop into periodontistis. Patients with gingivitis, therefore, should be monitored professionally, especially those patients with other risk factors (attachment loss, age, smoking, and abnormal tooth mobility). In patients without substantial attachment loss, professional examination, prophylaxis, and oral hygiene instruction should be provided once or twice a year, depending on the presence of other firsk factors. All patients who have been treated for periodontitis should be recalled, after completion of treatment and a healing phase, every 3 to 4 months. Sites with active periodontitis should be re-treated. Topical use of fluorides is recommended.

A variety of facial skin problems are encountered in a busy pediatric dental practice. The dentist should recognize and be able to identify the moer common important skin lesions. The etiology, presentation, and prognosis of acne vulgaris, impetigo, warts, molluscum contagiosum, ringworm, tinea versicolor, spider nevus, atopic dermatitis, seborrhea, herpes simplex, and lesions of child abuse are discussed. Several of these conditions require prompt referral to a pediatrician or dermatologist.

Complete-denture therapy involves a complex interplay between biologic demands and technical limitations. Success with complete-denture therapy is reportedly high. Dissatisfied denture patients, although few, do exist. This paper reviews some of the common faults reported with complete dentures.

An innovative fixed partial denture design for restoring a posterior edentulous space is described. The distal retainer is conventionally luted with a zinc phosphate cement, and the mesial retainer is luted with a resin cement. Contingency planning, which involves placement of a nonrigid connector between the pontic and the distal retainer, allows recementation of the resin-luted segment if the resin bond fails.

Composite resin-retained fixed partial dentures are widely accepted as an alterantive to conventional prostheses. This article describes the treatment of a patient in whom both maxillary lateral incisors were missing and space for normal-sized pontics was insufficient. The incisors were replaced bilaterally with a resin-bonded fixed partial denture consisting of a cantilevered resin-bonded framework with a ceramic pontic that overlapped the mesial portion of the canine's facial aspect. This design created an esthetically acceptable prosthesis through a conservative and simple approach.

A case report involving vertical root fracture in an endodontically treated mandibular left first molar is presented. Pain and extensive tissue damage occurred in the area 2 years after root canal therapy. The periapical radiograph suggested endodontic failure, and re-treatment was initially considered. However, the problem was related to a complete vertical root fracture in the distal root, which was only visible after removal of the gold crown. The toorth was extracted because severe periodontal destruction had been caused by the root fracture.

This study was designed to observe the healing and bridging capacity of mechanically exposed pulps that were capped with silicate or zinc phosphate cements and biologically sealed with zinc oxide-eugenol cement to exclude bacteria. In six monkeys, Class V facial cavities with pulpal exposures were randomly distributed throughout 105 teeth, of which 80 were directly capped, 40 with silicate cement and 40 with zinc phosphate cement. Twenty of each group were filled to the cavosurface margin with the respective cement and 20 were surface sealed to the cavosurface margin with zinc oxide-eugenol cement. The remaining 25 exposures were capped with calcium hydroxide and amalgam as controls. Tissues were obtained by perfusion fixation after intervals of 21, 14, 10, 5 and 3 days. The 25 pulps capp ed with calcium hydroxide showed cell migration and organization at 5 days and dentinal matrix deposition at 10 days. At 3 and 5 days, all exposures in the experimental groups showed clot resoltuion. At 10 days, fibroblasts had stratified against the cement interface. At 14 days, pulps in both experimental groups showed new dentinal bridge formation directly adjacent to the acidic cements. The 21-day experimentally capped and sealed pulps presented healing similar to the controls. This study indicates that acidic components of silicate and Zinc phosphate cements are not directly respondible for pulpal inflammation or necrosis. The exposed dental pulp possesses an inherent healing capacity for cell reorganization and dentinal bridge formation when a bacterial seal is provided.

The susceptibility of five bacterial species to seven dentinal bonding agents was examined in vitro. Agar diffusion tests using filterpaper disks containing 10 uL each of conditioner, primer, or resin were performed on blood agar and mitis salivarius bacitracin agar. Chlorhexidine (0.2%) was used as a positive control. After incubation, zones of inhibited bacterial growth were measured. Of all the compounds tested, Gluma cleanser and Gluma etchant showed the strongest growth inhibition for all bacterial strains. No antibacterial effect was noted for Prisma Universal Bond 2 and Superlux Universal Bond 2 systems. The primers of Gluma, Denthesive, and Scotchbond 2 displayed antibacterial activity that, in some cases, was comparable to that of 0.2% chlorhexidine. Zones of inhibition were seen for the resin materials of Scotchbond 2 and Tripton with Streptococcus mutans, Streptococcus sanguis and Actinomyces viscosus. No inhibition was seen after these resins were cured, whereas the antibacterial effect of XR-Bond on S sanguis and A viscosus was not affected by light curing.

Recently, simple radiometers for measuring the intensity of dental curing lights have been introduced. This study examined the relationship among light intensity measurements by three radiometers, distane of curing tip from composite resin, and resin polymerization (as indicated by microhardness). Light intensity measurements, which decreased with increasing distance from the curing tip, were strongly correlated with composite resin hardness. Reduced light intensity produced softer composite re sin particularly on the bottom of specimens (2-mm depth). The different radiometers provided similar indications of the changes in light intensity at various curing distances.