Quintessence International, 01/1990

The effects of eight disinfectants commonly used in dental practice on the vital physical properties of a fully set die stone were examined. Distilled water was used as a control. The properties used to evaluate tile effects of the disinfectants were detail reproduction, surface hardness, bulk strength, dimensional accuracy, and chemical interaction. Some of the disinfectant solutions where found to be reactive and to alter the properties of the stone to various degrees. However, two of the agents where less reactive and caused little or no observable change in the physical properties of the stone.

Most older units that drive high-speed dental handpieces include a retraction device designed to prevent dripping of fluids from the water-spray line after the unit has been turned off Oral fluids and debris may be drawn, along with water, into the water line. Bacteria and debris, unless deliberately flushed out of the water line, may be transmitted to the next patient. Most new units now have mechanisms to prevent retraction. A new dental control unit, designed to eliminate mechanical aspiration of oral fluids, was tested. A kit to test the level of retraction in the water-spray line was also examined. The new unit was found to be effective in protecting the unit water from contamination by oral microorganisms, thereby protecting patients from cross-contamination. However, the control of retraction did not prevent the colonization of the water line by aquatic bacteria. Both internal and external sources of microorganisms must be controlled.

Five new visible light-curing cavity liners/bascs that contain fluoride were evaluated for fluoride release over a 17-iteek period. Fluoride was released from all the materials, but the level of fluoride release decreased significantly (P .01) over the test period. There was also a statistically significant (P .05) difference among the materials in the amount of fluoride released.

This study evaluated at the in vitro level the antifungal effectiveness of nystatin, chlorhexidine, and a homologous histidine polypeptide on the surface of acrylic resin disks. The agents were used in a way that simulated storage of a denture by a denture wearer. Results indicated that pretreatment with poly-L-histidine was not protective against C albicans adherence and growth regardless of whether disks were stored in water or in the open air for the 8-hour period following yeast contamination. Chlorhexidine was total effective in preventing C albicans attachment to, and growth on, the acrylic resin, even after a period of 8 days of turbidimetric monitoring. Pretreatment with Nystatin, followed by drying, was protective, yielding results similar to those obtained with chlorhexidine.

The amount of occlusal surface area covered when fissure sealant is applied to a tooth has not been previously reported. This study measured the occlusal surface area and sealant surface area using a computer-driven profilometric system. Twenty-two recently erupted, caries-free premolars were used. The mean occlusal area for all premolars was 34.34 mm² ±4.42 mm². The mean surface area of applied sealant for all teeth was 8.06 mm²± 1.67 mm², and the mean percentage of occlusal surface area covered by sealant was 23.9 7% ±5.02%. The occlusal surface area of mandibular first premolars was signnificantly smaller than that of the other premolar groups. However, this difference was not reflected in the area of sealant applied to premolars or in the percentage of occlusal surface covered by sealant. Mandibular first premolars required the same amount of coverage as the other tooth groups.

Mandibular premolars are used as a model to discuss various strategies for the design of removable partial dentures. Factors that must be taken into consideration as the prosthesis is designed, such as coronal and radicular anatomy of the abutment teeth, the relationship of the abutment teeth to other teeth, and the presence of existing restorations, are also identified.

High expectations may contribute to stress in the patient and dentist during dental treatment. Esthetic and restorative results can be predicted for laminate veneers by using a powder blower and a liquid dispenser preoperatively to form self-cured resin veneers. Trial veneers are formed in a precision salt and pepper technique that conserves materials and time. The trial veneers are placed, without tooth preparation, on the treatment site so that the patient can preview the planned treatment and so that the dentist can explain proposed treatment in a reversible procedure. This may circumvent misunderstandings between dentist and patient and allow the consideration of alternate treatment plans.

In the past, the primary focus of dentistry has been on the alleviation of pain and stopping the progression of disease. The reduction in the prevalence of dental caries, along with advances in adhesive technology, have combined to revolutionize the practice of dentistry today. The modern dentist, using the latest available cosmetic techniques, is now able to satisfy the emotional wants and needs of patients. The public, well informed about the possibilities for anterior esthetics, now desire tooth-colored restorations in the posterior. A new heat- and pressure-curing resin inlay/onlay material and the clinical and laboratory technique for its use are discussed.

The effective use of two osseointegrated Brånemark implants for the replacement of a single first molar is described. A first molar lost to endodontic failure was replaced using Two 10-mm titanium Fixtures in the area previously occupied by the mesial and distal roots of the molar. The use of multiple fixtures in the molar area provided a better distribution of forces to the alveolar bone. At 1-year recall, the patient exhibited excellent oral hygiene and normal function. Adequate bone dimensions are a prerequisite to this treatment.