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Biomedical subjects

F M Gardner

Publications and source records attributed to F M Gardner.

16 recordsLinked to original sources

A comparison of impression techniques for the CeraOne abutment.

PURPOSE: This study measured the accuracy of two impression techniques recommended by Noblepharma to be used with their CeraOne single tooth implant restoration. The first technique was to lute the impression transfer coping to the impression tray with autopolymerizing acrylic resin. The second was to leave the transfer coping free-standing in the impression material. MATERIALS AND METHODS: Thirty-five samples were made of a polyvinyl impression of the CeraOne transfer coping free-standing in the set impression material. Thirty-five samples were made of a polyvinyl impression of the CeraOne transfer coping luted to the impression tray with autopolymerizing acrylic resin. A jig was fabricated and used to record the spatial relations of the impressions and the transfer copings in reference to the jig. A light microscope was used to measure the distance between fixed markings on pressure sensitive paper, representing impression variations. RESULTS: The mean discrepancy in the horizontal plane for nonluted impressions was 0.094 mm, and for luted impressions, it was 0.275 mm. The mean discrepancy in the vertical plane for nonluted impressions was 0.154 mm, and for luted impressions, it was 0.192 mm. The differences found between the group with the luted impression tray and the group with the nonluted impression tray were found to be statistically significant. CONCLUSIONS: The more accurate of the two techniques is to transfer the impression coping without luting it to the impression tray.

Analysis of Variance

Composite dowels and cores: effect of moisture on the fit of cast restorations.

A study was undertaken to evaluate the effect of interim restorations on the dimensional stability of composite post and core buildups subjected to moisture during the fabrication of cast restorations. Dimensional change associated with composite dowel and core buildups did not significantly alter the fit of cast restorations compared with natural teeth under the same conditions. The use of composite dowels and cores for the restoration of endodontically treated teeth is not contraindicated because of potential dimensional instability of the resin when exposed to moisture. Well-fitting interim restorations for either natural teeth or composite dowel and core buildups improved the fit of cast restorations 23% to 36%.

Composite Resins

A survey of crown and fixed partial denture failures: length of service and reasons for replacement.

The mean length of service of all restorations observed in this study was 8.3 years. Caries was the most common cause of failure, affecting 22.0% of the units failed and leading to the necessity for replacement of 24.3% of the units observed. Mechanical problems accounted for 69.5% of the failed units as opposed to 28.5% for oral disease. Resin veneer metal crowns provided the longest service of all crown types observed (13.9 years) and failed most frequently because of worn or lost veneers. The complete veneer metal crown had a life span of 6.1 years and was most likely to fail because of caries or defective margins. Ceramic-metal crowns also showed a relatively short period of service at 6.5 years, needing replacement primarily because of porcelain failure or poor esthetics. The resin-veneer metal crown also provided the longest service as a retainer, with a mean length of service of 14.7 years. This was closely followed by the partial veneer retainer (14.3 years), while the ceramic-metal retainer had the shortest life span (6.3 years). No apparent relationship was found between the span of prosthesis and its length of service. The six-unit canine-to-canine fixed partial denture exhibited the greatest longevity of the prostheses studied (10.4 years), while the two-unit cantilever fixed partial denture provided a mean of only 3.7 years of service before replacement was required.

Crowns

A comparison of healing and pain following excision of inflammatory papillary hyperplasia with electrosurgery and blade-loop knives in human patients.

Twenty human patients participated in a study designed to compare electrosurgery with blade-loop knives for the excision of inflammatory papillary hyperplasia in a split-mouth study. Questionnaires were used to assess pain and patient preference during a 2-week postoperative period, and photographs were made to chronicle the healing process. Healing occurred at approximately the same rate following each procedure. The majority of subjects did not perceive a difference in discomfort with either technique on the day of surgery or at any time during follow-up. Of those who did have a preference, a significant majority favored electrosurgery on the day of treatment. This preference became statistically insignificant on the second postoperative day and beyond.

Adult