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Biomedical subjects

M R Pintado

Publications and source records attributed to M R Pintado.

30 records · Page 2Linked to original sources
PubMed1990

Measurement of fissure sealant surface area by computer.

The amount of occlusal surface area covered when fissure sealant is applied to a tooth has not been previously reported. This study measured the occlusal surface area and sealant surface area using a computer-driven profilometric system. Twenty-two recently erupted, caries-free premolars were used. The mean occlusal area for all premolars was 34.34 mm2 +/- 4.42 mm2. The mean surface area of applied sealant for all teeth was 8.06 mm2 +/- 1.67 mm2, and the mean percentage of occlusal surface area covered by sealant was 23.97% +/- 5.02%. The occlusal surface area of mandibular first premolars was significantly smaller than that of the other premolar groups. However, this difference was not reflected in the area of sealant applied to premolars or in the percentage of occlusal surface covered by sealant. Mandibular first premolars required the same amount of coverage as the other tooth groups.

Analysis of Variance↗
PubMed1989

The wear of enamel when opposed by ceramic systems.

The wear of enamel when opposed by different ceramic systems was investigated by use of an artificial oral environment. Cerestore, Dicor, and Ceramco discs were opposed by recently extracted natural teeth. The samples were exposed to 300,000 defined masticatory cycles under physiologic conditions. It was found that the wear mechanisms for Cerestore and Ceramco porcelains were similar, but were distinctly different from that of Dicor. The total volume loss of enamel was 50% less when opposed by Dicor, than when opposed by either the Cerestore or Ceramco porcelains. None of the samples had any external shade applied to their surfaces.

Aluminum↗
PubMedDate not supplied

Measurement of preventive resin restorations using computer profilometry.

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.

Child↗
PubMedDate not supplied

Quantitative changes in fissure sealant six months after placement.

Earlier studies have reported extensive volumetric loss of fissure sealant shortly after placement. To determine the volume of fissure sealant lost at six months, we used a servohydraulic profilometric apparatus in combination with computer graphics. Twenty-two premolar teeth were selected, and baseline silicone impressions were made of each tooth. The teeth were sealed and the occlusion adjusted where necessary. Impressions were made immediately of sealed teeth and again at six months. Epoxy replicas were made from all impressions, and their surfaces digitized by sequential profilometry. Using a three-dimensional root mean square (RMS) goodness-of-fit computer program, before sealant, after sealant, and six months after sealant computer-graphic images were superimposed. The volume of sealant lost after six months for all premolar teeth was X = 0.23 mm3 (maxillary second premolar: N = 9, X = 0.29 mm3; maxillary first premolar: N = 5, X = 0.27 mm3; mandibular second premolar: N = 4, X = 0.20 mm3; mandibular first premolar: N = 4, X = 0.08 mm3). The volume differences between tooth groups were not significant as measured by analysis of variance (ANOVA). These volumes represented a 13.99% loss of applied sealant for all premolars (maxillary second premolar: 19.72%; maxillary first premolar: 15.37%; mandibular second premolar: 8.46%; mandibular first premolar: 6.37%). The area of wear and the depth of wear also were measured.

Humans↗
PubMedDate not supplied

Evaluation of factors affecting the accuracy of impressions using quantitative surface analysis.

Impression material goes from a plastic to an elastic state during setting. Movement of the impression and excessive seating pressure during this transition can cause distortion in the impressions. The purpose of this study is to determine if the impression distortion is related to movement during setting or to distortion of the putty phase in the two-step impressioning technique. A master model of a maxillary quadrant of teeth was impressed using four different procedures: 1) one-step technique without movement (1S-NM); 2) one-step technique with movement (1S-M); 3) two-step technique without movement (2S-NM); and 4) two-step technique with movement (2S-M). An artificial oral environment and surface analysis technique of the Minnesota Dental Research Center for Biomaterials and Biomechanics were used to produce the impressions and measure their accuracy. A digitized image of the first premolar of the master model was aligned with a digitized image of the first premolar of each epoxy model using AnSur. The root mean squared difference (RMS) between the aligned images is a measure of the distortion. The corresponding RMS values for the different methods were: 1S-NM = 23.7 +/- 9.21; 1S-M = 20.4 +/- 3.9; 2S-NM = 20.5 +/- 7.7; 2S-M = 21.3 +/- 4.4. Statistical analysis using a two-way analysis of variance showed no difference at the 0.05 level of significance. Pairwise comparison using the Tukey method showed that neither technique (one-step vs two-step) nor movement is a significant factor. These results showed that low seating pressure will not cause any greater distortions in the two-step impression technique than in the one-step technique, and minor movement during the setting of the impression material will no cause distortion.

Analysis of Variance↗