Quintessence International, 03/1997

Decisions regarding the treatment of enamel pits and fissures, carious or not, can be difficult for the dentist; exceptional diagnostic acumen is required. In years gone by, teeth with Class I carious lesions were always restored with silver amalgam material; now, however, various treatment options are available to the clinician. Resin bonding, glass-ionomer systems, and visible light-curing technology have irrevocably changed restorative dentistry. This article reviews six methods for restoring teeth with Class I carious lesions or sealing those with susceptible pits and fissures.

C1-inhibitor deficiency, or hereditary angioedema, is a genetic disorder characterized by recurrent circumscribed, nonpruritic, nonpitting subepithelial edema. Minor trauma to the tissue, such as tooth extraction, can trigger life-threatening laryngeal edema. The use of fresh forzen plasma and/or danazol before treatment prevents angioedema attacks. A critical review of the treatment regimen and prophylaxis for C1-inhibitor deficiency is presented, and thre e new cases are described.

A patient had a maxillary posterior edentulous area and severely reduced interarch distance that precluded the use of a conventional removable partial denture. An all-cast-titanium denture base and occlusal surface was designed to fabricate a removable denture to restore the edentulous area. Titanium was cast in a centrifugal casting machine with electric arc melting design. The desirable characteristics of titanium, such as favorable mechanical properties, low density, and comparatively low cost, make this metal particularly effective and suitable for construction of an all-cast-metal denture base with a metal occlusal surface.

A passive fit between osseointegrated implants and the prosthesis supported by them is curcial to the correct distribution of the stress exerted on the implants. The accuracy of the impression procedure in duplicating the exact position of the implant abutment is one of the main contributors to passive fit. An impression technique is presented whereby the dentate and edentulous parts are duplicated in elastomeric material, providing both the flexibility needed to remove the impression and the required accuracy. Subsequent duplication of the implant zone with plaster, without removal of the tray, affords a high degree of accuracy.

Treatment with overdentures is an alternative to conventional complete prostheses. Different types of attachments can be placed in natural teeth that act as retainers for overdentures. The photoelastic relationship between the design of the attachment and the distribution of occlusal forces among the abutment teeth and the distal alveolar ridges was examined. The results were used to develop a classification for clinical cases so that the correct attachment design can be selected.

The treatment of periodontally diseased root surfaces with power-driven instruments is becoming increasingly important as an alternative to the use of hand instruments. Root surfaces of artificial teeth on a manikin were debrided under simulated flap operation conditions to determine if effectiveness was dependent on the instrument used (curettes or a modified sonic scaler tip) and/or the operator's degree of experience. Two quadrants were treated with each instrument. A morphometric evaluation followed. Debridement was faster with the diamond-coated sonic scaler tip than with hand instruments. With the sonic scaler, the time necessary for tre atment was reduced by 30%. The experienced operators treated about 80% of the root surface, while the inexperienced operators treated only about 65%. Treatment qual ity depended on the operator and not on the instrument used.

This in vitro study investigated the fracture resistance of dentin-bonded crowns constructed from four ceramic materials: feldspathic porcelain, aluminous porcelain, a glass-ceramic core material (Dicor), and a leucite-enriched ceramic (Empress). Forty sound maxillary premolar teeth were chosen and divided at random into four equal groups. The teeth were prepared with a standardized crown minimal preparation. The restored teeth were subjected to compressive loading. When the mode of fracture of the specimens was examined, it was found that four mode V (severe) fractures occurred in the Empress group, compared with none in the aluminous procelain group and one each in the feldspathic porcelain and Dicor groups. St atistical analysis indicated that the loads required to fracture Dicor specimens were significantly greater than those required to fracture the feldspathic and aluminous porcelain crowns but were not significantly different from the loads achieved by the Empress specimens.

This study aimed to examine the suitability of the diode laser with a wavelength of 810 nm for reducing bacteria in root canals. Forty-four extracted, endodontically prepared teeth were inoculated with Escherichia coli and Streptococcus faecalis. No bacterial growth was observed when the teeth were irradiated at an output power of 4 W and a pulse rate of 10 milliseconds, with breaks of 10 millise conds between the irradiations. Exposure time was five times 5 seconds. Infrared spectroscopic examinations revealed that irradiation at 4 W under even circling movements resulted in a maximum rise in temperature at 6 degrees C on the root surface. Stain penetration tests and scanning electron microscopic examinations revealed complete closure of the dentinal tubules on the irradiated root canal walls.