ABSTRACT
The amount of extracoronal material placed when a tooth is restored with a preventive resin restoration (PRR) was quantitatively measured together with the projected area of each cavity preparation. Thirty-three patients (mean age 11 yrs, 6 mos) requiring a PRR on a lower first permanent molar were selected. Impressions of the teeth were made with polyvinylsiloxane before and after cavity preparation and then restored with P-50 and Concise sealant. Following occlusal adjustment, a third impression was taken. Replicas were digitized using computer profilometry. Computer images of occlusal surfaces were superimposed using a "goodness of fit" method. The volume of extracoronal material placed on all molar teeth (n = 33) was X = 6.52 +/- 2.9 mm3. The mean depth applied was X = 222.52 +/- 83.09 mu and the mean area of material applied over the entire tooth surface was X = 27.13 +/- 5.72 mm2. The cavity preparations occupied, on average 19.02 percent of the occlusal surface.
