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D C Sarrett

Publications and source records attributed to D C Sarrett.

11 recordsLinked to original sources
PubMed1995

Wear resistance of dual-cured resin luting agents.

PURPOSE: To evaluate the three-body wear resistance of five commercially available dual-cured resin-based composite luting agents compared both in a dry state and after water storage. MATERIALS AND METHODS: Six specimens of each material were prepared and tested for three-body wear resistance in the ACTA wear machine for 250,000 cycles and the loss of material was measured with a profilometer. Material wear was measured under three conditions: dry storage, 6-month water storage, and 12-month water storage. RESULTS: One-way and two-way ANOVA and Tukey's HSD test of multiple comparisons revealed significant differences in wear resistance. Water storage did not significantly affect the wear resistance of four of the five materials. The order of wear resistance was: Cosmedent Insure > Vivadent Dual-Cement > Kerr Porcelite Dual Cure > Jeneric/Pentron Optec Luting Cement > Chameleon Mirage FLC (P < or = 0.0001). The rank order of wear resistance could not be readily predicted when based solely on the manufacturers' reported physical specification data.

Acrylic Resins↗
PubMed1994

The effect of water on polymer matrix and composite wear.

OBJECTIVES: Previous studies have demonstrated increased in vitro wear of composite after long-term water exposure. The increased wear effect was not clearly related to debonding of the filler from the matrix, resulting in accelerated loss of filler particles. The hypothesis tested in this experiment was that the changes in in vitro three-body wear of a composite following water storage are caused by changes in the wear resistance of the polymer matrix. METHODS: In the in vitro wear test used, a specimen wheel was rotated against an antagonist wheel in a slurry of millet seed and water. Specimens were fabricated of composite and polymer matrix only. Specimens were wear tested after 1 wk of ambient temperature dry storage and after 14, 20, and 26 mon of water storage at 37 degrees C. RESULTS: The wear of the composite significantly increased (23%) during the 26 mon of water storage. The wear of the polymer specimens increased slightly; however, the increase was not statistically significant. SIGNIFICANCE: Analyses of the data using a series model for the wear of a composite indicated that the increase in wear of the composite was not due to changes in the wear resistance of the polymer matrix. Instead, the increased composite wear was more likely due to increases in the dislodgment rate of filler particles and the wear rate of the filler itself.

Analysis of Variance↗
PubMed1994

Modeling the relationship between clinical, microbiologic, and immunologic parameters and alveolar bone levels in an elderly population.

A cross-sectional periodontal study of 74 subjects aged 65 to 75 years was performed. Clinical data were collected and related to microbiological and immunological data. A statistical model (step-wise multiple regression) of factors related to bone loss was created initially using clinical data only; then by adding either the microbiologic or immunologic data; and then by using clinical, microbiologic, and immunologic data together. When only clinical data were considered, three factors were found to have significant positive correlations with bone loss. Tooth mobility accounted for 17% of the variability in the alveolar bone level measurements, probing depth for 12%(r2), and plaque index for 3%, for a total of 32% of the variability explained by these clinical factors. Tooth mobility and probing depth were clinical factors which remained significant in the model when the microbiological data were also considered. As percentages of the total cultivable microbiota, E. corrodens (r2 = 14%) and black-pigmenting Prevotella intermedia (r2 = 4%) correlated positively with alveolar bone loss. The addition of the microbiologic data only increased the r2 to 33%. When immunological data were considered with the clinical data, pocket depth and tooth mobility were the clinical parameters which remained in the model. IgG antibody levels to P. gingivalis W83 and/or 381 (r2 = 24%) A. actinomycetemcomitans 627 (r2 = 2%) were the significant immunologic measures having a positive correlation with bone loss. Anti-F. nucleatum levels had a significant negative correlation. A total of 50% of the variability in alveolar bone level was accounted for in the model by the addition of specific serum antibody levels to subgingival plaque microorganisms. When clinical, microbiological, and immunological measurements were all considered together, antibody to P. gingivalis W83 and/or 381 (r2 = 42%), percentage of B-lymphocytes (r2 = 3%), probing depth (r2 = 4%), anti-E. corrodens levels (r2 = 2%), and anti-P. gingivalis 33277 levels (r2 = 4%) all had significant positive correlation with loss of alveolar bone. The number of enteric bacteria, anti-F. nucleatum levels, and anti-P. intermedia levels each had a significant negative correlation with alveolar bone heights. The r2 for this model was 75%. These results indicated that antibody levels to subgingival plaque microorganisms and tooth mobility were the best predictors of bone loss in the elderly patients tested in this study.

Age Factors↗
PubMed1992

Visual and profilometric wear measurements.

Wear of composites can be estimated by the degree of marginal discrepancy between the prepared cavity wall and the occlusal margins of composites. Such evaluations are done on casts by comparing and rating the marginal discrepancy with those on standard casts. We analyzed the reliability of this technique on metal and stone specimens. These specimens contained grooves of different width and depth. For the visual comparison we used stone casts of machined standards of known groove depth. We measured the depths of the metal specimens with a profilometer and made stone casts of these original specimens. Using the stone casts of the standards, five dentists estimated the unknown groove depths on the remaining stone casts. These estimates were done under standardized conditions and repeated by each dentist on five different occasions. The results showed that visual depth evaluations of die stone specimens underestimated the depths when compared with the values measured with a profilometer on the original metal models. One investigator gave significantly different (p less than 0.05) groove depth estimates at different occasions.

Calcium Sulfate↗
PubMed1991

Water and abrasive effects on three-body wear of composites.

The degrees of in vitro three-body wear resistance of a hybrid, a small-particle, and a microfilled composite were determined after water storage for up to 24 months. The hybrid composite was the most wear-resistant, while the microfilled composite showed the most wear. The hybrid composite showed no loss of wear resistance as a result of water storage. The small-particle composite showed a decrease in wear resistance after water storage only when tested with silicon carbide abrasive. The wear resistance of the microfilled composite decreased following water storage when tested with either a soft (CaCO3) or a hard (SiC) abrasive. For all composites, the soft abrasive was not capable of causing preferential wear of the polymer matrix, as observed on in vivo specimens. Instead, the filler particles became flattened, with minimal loss of interparticle substance. The hard abrasive did cause preferential wear of the matrix. All composites absorbed water and leached silicon during water storage, indicating that the filler-polymer bond was attacked by hydrolytic degradation. Scanning electron microscopic evaluation of the three-body wear specimens indicated that the in vitro wear method did not duplicate in vivo wear conditions (e.g., the hard abrasive caused excessive wear and chipping of the filler particles in vitro, a pattern that was not usually observed in vivo). Filler-polymer de-bonding was observed on in vivo specimens of all the composites, while it was found only on the in vitro microfilled composite specimens. These findings suggest that filler dislodging is a complex process that cannot be simulated with the in vitro wear method used in this study, not even after prolonged water storage.

Analysis of Variance↗
PubMed1984

Heat generated when threaded pins are cut: a comparison of techniques.

The temperature rise of threaded pins was measured when cut under various conditions and with different instruments. The air-water coolant and intermittent cutting produced significantly lower temperature rises than the air coolant and constant cutting, respectively. No particular carbide bur or diamond stone is recommended since little difference existed among them with respect to heat generation.

Air↗