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Biomedical subjects

T E Donovan

Publications and source records attributed to T E Donovan.

At least 37 records · Page 2Linked to original sources
PubMed1996

Materials for conservative posterior restorations.

Advantages and disadvantages of amalgam and cast gold restorations are compared to those of new tooth-colored restorations. Success can be achieved using many different types, but the benefits of traditional restorations should not be forgotten.

Bicuspid↗
PubMed1996

The versatile and esthetic metal-ceramic crown.

The predictability, many advantages and remarkable adaptability of metal-ceramic crowns account for their frequent use. Metal-ceramic crowns will continue to be one of the most widely used dental restorations.

Bicuspid↗
PubMed1995

Tensile bond strength of polyvinyl siloxane impressions bonded to a custom tray as a function of drying time: Part I.

Time-dependent bond strength studies of two polyvinyl siloxane impression materials to acrylic resin disks with their respective adhesives were studied to determine the optimal time for maximum bond strength. Six groups were tested with varying adhesive dry times of 0, 7, 15, and 60 minutes and 8 and 24 hours before testing. The results indicated that the bond strength of the adhesive increased at least twofold from time zero to 7 minutes adhesive dry time and peaked at 60 minutes for one of the materials and at 8 hours for the other. Bond strengths increased rapidly to the 15-minute test interval and then seemed to plateau. Both materials exhibited decreased adhesive bond strengths at 24 hours.

Acrylic Resins↗
PubMed1995

Treatment planning and soft tissue management for optimal implant aesthetics.

Aesthetic restoration of single anterior teeth is one of the most difficult procedures to execute. This article discusses patient selection criteria, implant position and its relationship to the aesthetic outcome. The importance of soft tissue management in all phases of surgical and restorative phases is emphasized. Guidelines are given for the successful delivery of this service for the patient that will preserve adjacent teeth and fulfill functional and aesthetic needs.

Dental Implantation, Endosseous↗
PubMed1993

Inhibition of polymerization of polyvinyl siloxanes by medicaments used on gingival retraction cords.

Inhibition of polymerization of polyvinyl siloxane materials by latex products is well documented. It is thought to be caused by contamination of the chloroplatinic acid catalyst by sulfur compounds. Many medicaments, such as aluminum sulfate and ferric sulfate, used on gingival retraction cords have been accused of causing inhibition of set of polyvinyl siloxane materials. Several of these medicaments were tested with two polyvinyl siloxanes and found not to cause any inhibition of set.

Alum Compounds↗
PubMed1993

Annual review of selected dental literature: report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry.

The annual review of selected dental literature this year cites 384 published papers and reports. This year's review contains more editorial comment than reviews of years passed. New data on the biological responses to materials is emphasized in several sections. Observations on new compounds able to prevent plaque formation are presented. Clinically relevant advances in knowledge concerning the etching of different tooth structures are reported along with the effect of etching procedures on the dental pulp. Evaluation of periodontal diseases in all age groups is a topic. Limitations of current diagnostic techniques in periodontal disease, temporomandibular disorders, and implant therapy are included. There are new views on the use of dental amalgam. The future use of dental mercury is predicted. Interest in new ceramic systems is indicated as the demand for esthetics continues. Clinical information is emphasized over scientific information throughout this year's review.

Dental Implants↗
PubMed1993

Use of radicular attachments with endodontically treated teeth.

An extension of conventional overdenture philosophy with the use of radicular attachments in endodontically treated teeth can be used to improve stability, reduce bony resorption and proprioception and augment retention. However, radicular attachments are not appropriate in all cases. Indications, requirements, advantages and disadvantages of this type of prosthesis are provided.

Dental Prosthesis Design↗
PubMed1993

Conservative indirect restorations for posterior teeth. Cast versus bonded ceramic.

The practitioner today has a number of alternative restorative modalities from which to chose when faced with the necessity of restoring posterior teeth. The primary options with extensively broken down posterior teeth are cast gold and bonded ceramic inlays, onlays, and partial veneer restorations. The dentist and informed patient should make the choice of which modality is appropriate based on a number of criteria. Certainly, based on the criteria of basic physical properties, potential for marginal integrity and stability of that integrity, cast gold is the material of choice. In terms of conservation of tooth structure and systemic biocompatibility, both restoration types are excellent. With regard to effects on long-term pulpal health, much remains unknown with many of the materials used with bonded restorations at the present time. Conservative cast gold restorations have proved to be very successful in this regard over the long term. The potential for tooth strengthening with bonded restorations is certainly an exciting, but as yet, unproven, clinical reality. Thus, until those clinical data are available, the most predictable means of restoration of extensively broken down posterior teeth is with partial-coverage cast gold, protecting cusps at risk as required (Fig. 9). As mentioned previously, cast gold inlays are also a very conservative and predictable restoration (Fig. 10). Both cast gold and bonded ceramic restorations are technically demanding, but the details required to produce excellent gold castings are well defined, and can be learned readily. Much remains to be learned regarding the materials and the techniques used to fabricate bonded ceramic restorations. Priority issues would seem to be reaching a consensus regarding the details of tooth preparation and the development of improved luting resins with improved wear resistance. Simplified techniques to improve the quality of the fit of these types of restoration also are of paramount importance. The requirement for an esthetic, or, more properly, use of a tooth-colored restoration in a posterior tooth, should be evaluated carefully for each individual restoration. Often it is possible to restore a tooth with cast gold with minimal or no display of metal. The patient will then receive the long-term benefit of cast gold and not compromise on esthetics. It is our obligation as diagnosticians to educate our patients so that they are in a position to choose, when indicated, this most cost effective of restorative options.

Bicuspid↗
PubMed1992

Polyvinyl siloxane impression materials: a review of properties and techniques.

Polyvinyl siloxane impression materials have been shown to have excellent properties as impression materials; however, they are sensitive to manipulative variables. Several methods of using very high viscosity (putty) materials to form "trays" to obtain uniform bulk of the wash impression are described, and the disadvantages of each of these techniques is pointed out. It is recommended that for best results acrylic resin custom trays should be used routinely. The interaction of polyvinyl siloxane materials with latex products is also discussed and problems that this inhibition can cause are stated. Suggestions to avoid this interaction are outlined. One of the disadvantages of the impression materials is that it has a relatively short working time. Refrigerating the material will increase working time without affecting accuracy.

Acrylic Resins↗
PubMed1991

Ceramic restorations: cast metal and cast glass.

Pertinent articles published between October 1989 and September 1990 related to metal-ceramic and all-ceramic crowns are reviewed. The main topic groupings are: 1) color and esthetics with metal-ceramics; 2) bond strength of metal and ceramic materials; 3) all-ceramic alternatives; and 4) the porcelain surface. Research published during this period advanced knowledge of photospectrophotometry and thermomechanical compatibility of porcelain-metal systems. Deficiencies in fit and strength for some all-ceramic systems are described. Further evidence was published supporting the efficacy of polishing porcelain. Additional documentation regarding the etching of ceramic materials, including Dicor (Caulk Company Ltd., Milford, DE) was produced. More research into use of titanium and titanium alloys as substructures for ceramic materials is required.

Color↗
PubMed1991

Indirect inhibition of polymerization of a polyvinyl siloxane impression material: a case report.

The inhibition of polymerization of polyvinyl siloxane impression materials by direct contact with latex gloves has been well documented. Indirect intraoral inhibition of polymerization that results from contact of oral tissues with latex gloves during tooth preparation and gingival retraction procedures has been reported. This case report illustrates the problems that can occur when the dentist used polyvinyl siloxane impression materials while wearing latex gloves. In the reported case, the inhibition is severe and obvious; in most situations the inhibition of polymerization is more subtle and is frequently undetected. Clinicians must be aware of this potential problem and the solution to it.

Dental Impression Materials↗