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Biomedical subjects

J P Moffa

Publications and source records attributed to J P Moffa.

At least 19 recordsLinked to original sources

Clinical evaluation of a composite resin system with a dentin bonding agent for restoration of permanent posterior teeth: a 3-year study.

This study evaluated the clinical performance of a visible light-cured small particle bimodally filled hybrid condensable composite resin system that included a dentin bonding agent compared with an amalgam alloy in class II restorations of permanent teeth. A total of 108 restorations were placed in 34 patients. Fifty-three composite resin and 55 amalgam restorations were inserted. Each restoration was evaluated immediately after placement and then on an annual basis for a 3-year period using the Public Health Service (PHS) criteria. In addition, the Moffa-Lugassy scale was used to measure the loss of material on the occlusal surface of these materials. One hundred percent of the resin and amalgam restorations were evaluated, measured, and reasons for replacement were recorded over the 3-year period. There was no significant difference (p greater than 0.05) in the clinical performance of the composite resin and the amalgam when evaluated by the PHS criteria. Analyses of wear at each of the three annual recall periods did not reveal any significant difference (p greater than 0.05) between the two restorative materials when measured by the Moffa-Lugassy scale.

Bicuspid↗

Alternative dental casting alloys.

The diversity of alloys available to the dental practitioner has never been more extensive. We now have the opportunity to select alloys based on the individual patient's specific biologic, functional, and economic requirements. There is no one alloy suitable for all applications, because in metallurgy there is a constant trade-off in properties as changes in formulations are made. To make optimal use of the choices available, and for ethical and medicolegal considerations, it is incumbent upon the practitioner to be aware of the identity and composition of the alloys prescribed.

Chemical Phenomena↗

Effect of oxidation on ceramometal bond strength.

The ceramometal bond strength between SMG-3 gold alloy and Ceramco porcelain was evaluated using seven different oxidation cycles. The control group was not oxidized. Three groups were oxidized under vacuum at a temperature of 1,925 degrees F. The metal was heated (1) just until it reached temperature, (2) for 5 minutes, and (3) for 10 minutes. The last three groups were oxidized without a vacuum, with the time-temperature heat regimen the same as for the previous three groups. The group using an oxidation cycle without a vacuum and a temperature of 1,925 degrees F for 10 minutes was the only group that statistically differed from the control group.

Chemical Phenomena↗

Creep rate of porcelain-bonding alloys as a function of temperature.

The method of beam bending has been demonstrated for measurement of creep rate as a function of temperature. Representative high gold-, gold-palladium-, and palladium-silver-based alloys have different activation energies for high temperature creep, and thus their relative "sag" behavior is expected to depend on the temperature at which the comparison is made. Near the solidus temperature, creep rates for the alloys investigated differ by an order of magnitude and become increasingly different at lower temperatures. Depending upon the presently unknown mechanisms involved in "sag" and in "margin opening" during porcelain firing, control of activation energy has varying potential for modifying creep-induced discrepancies of PFM restorations.

Chemical Phenomena↗

Clinical evaluation of three acid-etch composite resin systems: two-year report.

One hundred fifty-seven fractured anterior teeth were restored with one of three acid-etch composite resin systems and were clinically and radiographically evaluated for 24 months. Of the three systems evaluated, the material activated by ultraviolet light provided the highest retention rate and clinical acceptance.

Acid Etching, Dental↗