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Biomedical subjects

R E Lorey

Publications and source records attributed to R E Lorey.

8 recordsLinked to original sources
PubMed1993

The potential for bonding titanium restorations.

PURPOSE: The use of titanium for implants has shown the biological acceptance of the metal. Recently, methods of using titanium for restorations, crowns, and bridges have been introduced using both cast and spark erosion systems for fabrication. A potential also exists for using titanium for bonded (Maryland) bridges. MATERIALS AND METHODS: In this study, the potential for bonding titanium was investigated by cementing with various adhesives: (A) metal to metal, (B) metal to enamel, and (C) comparing with a known procedure of bonding nickel-chromium. Truncated cones of pure titanium were fabricated with a 5-mm circular face for bonding to a larger titanium disc embedded in a plastic ring. A special jig was used to pull the bonded cone from the disc on an Instron tensile testing machine (Instron Corporation, Canton, MA). The resin-metal adhesives used were: (1) Infinity, (2) Metabond, (3) All-Bond 2, and (4) Panavia. These were compared with (5) nickel-chromium cones sandblasted and bonded to nickel-chromium with Panavia. Titanium cones were also bonded to human enamel with (6) Panavia and (7) Metabond. The 10 samples in each group were subjected to tensile force, and point of fracture was recorded. The data were subjected to an analysis of variance with a Scheffe F test at the 95% level of significance. RESULTS: The results of tensile forces in MPa were (1) Infinity, 28.1 +/- 3.6; (2) Metabond, 28.1 +/- 1; (3) All-Bond 2, 49.5 +/- 4.3; (4) Panavia, 57.9 +/- 3.1; (5) Panavia to nickel-chromium, 42.9 +/- 6.6; (6) Panavia to enamel, 18.5 +/- 4.7; and (7) Metabond to enamel, 19.3 +/- 3.5. Titanium was most effectively bonded with All-Bond 2 and Panavia, with Panavia samples significantly better than Panavia to nickel-chromium samples. CONCLUSIONS: It was concluded that titanium bonded restorations with certain adhesive cements were a definite possibility.

Analysis of Variance↗
PubMed1980

Abutment considerations.

The abutment consideration is but one step in the fabrication of a stable base appliance. This step, however, is a vitally important one. If carried out poorly, the casting can be lost and the tooth and periodontal tissues severely damaged or destroyed. All the steps considered in the fabrication of a case are like links of a chain. If one link fails the entire chain (or case) is broken or impaired. When the conditions of proper room for the attachment, crown contour, retention, and criteria of good preparation techniques and design are met, sound abutment considerations will be a strong link in the success of the attachment.

Composite Resins↗
PubMed1978

Improving interrater agreement in evaluation in dentistry by the use of comparison stimuli.

Research shows that use of rating scales with precisely defined scale points improves interrater agreement. Instead of words, scale points may be defined by products for which ratings have been established by consensual agreement. These products serve as standards for raters. In two studies, raters assessed student products using conventional rating scales and identical scales together with comparison stimuli (photographic exemplars) of consensually established values of 3 (adequate) for each criterion. Results of the first study (but not the second) clearly confirmed the contribution of exemplars to interrater agreement. Findings suggested that single exemplars significantly enhance agreement for criteria on which the ideal is an end point on a continuum. Multiple exemplars may be necessary for other criteria. Comparison stimuli offered promise for improving interrater agreement, but further work is necessary to adapt their use for complex criteria that frequently define the quality of dental preparations.

Crowns↗