Biomedical subjects

H M Snuggs

Publications and source records attributed to H M Snuggs.

4 recordsLinked to original sources

PubMed1995

A new copolymerized composite resin system: a multiphased evaluation.

Most microfilled composite resins are relatively resistant to generalized wear; however, they commonly exhibit poor resistance to localized wear because of debonding of prepolymerized particles from the resin matrix. A copolymerized new composite resin, in which the filler particle trimethylolpropane-trimethacrylate is chemically bonded to the resin matrix, is evaluated. Epic-TMPT was subjected to both generalized and localized wear tests that revealed that its wear resistance was higher than that of other composite resin systems. Epic-TMPT in posterior occlusal cavities showed less than 8 microns of wear for each restoration, 1 year after placement. Placement of Epic-TMPT into large anterior abfraction lesions without mechanical retention, with surface etching, and subject to severe traumatic occlusion resulted in 87% retention 1 year after placement. In vivo usage biocompatibility tests demonstrated no pulpal irritation or inflammation when Epic-TMPT was placed on vital dentin of crown preparations with complete enamel removal.

Animals↗

PubMed1994

Pulpal response to adhesive resin systems applied to acid-etched vital dentin: damp versus dry primer application.

A number of studies have reported that acid etching of dentin is toxic to the cells of the odontoblastic layer and dental pulp. Other studies report that pulpal inflammation is a consequence of bacterial microleakage. The purpose of this study was to observe the degree of pulpal healing after pretreatment of vital dentin prior to placement of All-Bond and Scotch-bond 2 composite resin adhesives. Zinc oxide-eugenol cement and an acidic cement were employed as controls. One hundred twelve Class V nonexposed cavity preparations were placed throughout the dentitions of five healthy adult rhesus monkeys and observed at 3, 25, and 80 days. Various dentinal pretreatment procedures were employed. The All-Bond Universal primer system was placed on air-dried vital dentin in 23 cavities and on damp vital dentin in 27 cavities. Scotchbond 2 was placed as per manufacturer's instructions. All treatment procedures, materials, and times were represented in all animals. Placement of silicate cement resulted in the most severe pulpal responses at all time periods. Stained bacterial profiles in the remaining dentin on the axial walls of inflamed control pulps were associated with severe pulpal inflammation. These results indicate that acid etching of vital dentin does not impair pulpal healing in deep Class V cavities.

Acid Etching, Dental↗

PubMed1993

Pulpal healing and dentinal bridge formation in an acidic environment.

This study was designed to observe the healing and bridging capacity of mechanically exposed pulps that were capped with silicate or zinc phosphate cements and biologically sealed with zinc oxide-eugenol cement to exclude bacteria. In six monkeys, Class V facial cavities with pulpal exposures were randomly distributed throughout 105 teeth, of which 80 were directly capped, 40 with silicate cement and 40 with zinc phosphate cement. Twenty of each group were filled to the cavosurface margin with the respective cement and 20 were surface sealed to the cavosurface margin with zinc oxide-eugenol cement. The remaining 25 exposures were capped with calcium hydroxide and amalgam as controls. Tissues were obtained by perfusion fixation after intervals of 21, 14, 10, 5 and 3 days. The 25 pulps capped with calcium hydroxide showed cell migration and organization at 5 days and dentinal matrix deposition at 10 days. At 3 and 5 days, all exposures in the experimental groups showed clot resolution. At 10 days, fibroblasts had stratified against the cement interface. At 14 days, pulps in both experimental groups showed new dentinal bridge formation directly adjacent to the acidic cements. The 21-day experimentally capped and sealed pulps presented healing similar to the controls. This study indicates that acidic components of silicate and Zinc phosphate cements are not directly responsible for pulpal inflammation or necrosis. The exposed dental pulp possesses an inherent healing capacity for cell reorganization and dentinal bridge formation when a bacterial seal is provided.

Animals↗

PubMed1992

Reparative dentin: factors affecting its deposition.

Results of this study showed no correlation between the thickness or amount of reparative dentin deposited and the type of dental restorative material placed at either 5 or 8 weeks in controlled Class V cavity preparations in monkey teeth. Factors such as preparation trauma from the bur, operator hand instrumentation, and microleakage of bacterial toxins played a greater role in the stimulation of reparative dentin than did material irritation or toxicity. Some differences in the thickness of the reparative dentin deposited were noted when teeth were grouped according to the amount of remaining dentin.

Analysis of Variance↗