Biomedical subjects

Peter E Murray

Publications and source records attributed to Peter E Murray.

21 records · Page 2Linked to original sources

PubMed2002

Cavity remaining dentin thickness and pulpal activity.

PURPOSE: To investigate pulpal injury by measuring odontoblast numbers, and pulp dentin repair activity by measuring reactionary dentin area, in relation to the remaining dentin thickness (RDT) of cavity preparations in 217 human teeth. MATERIALS AND METHODS: Cavities were restored with adhesive bonded composite, resin-modified glass-ionomer cement, zinc oxide-eugenol or calcium hydroxide materials. The teeth were extracted for orthodontic reasons between 20-381 days post-operatively, and odontoblast numbers and reactionary dentin area were analyzed histomorphometrically, and statistically using ANOVA. RESULTS: Reactionary dentin deposition was observed beneath cavities with a RDT above 0.5 mm as well as beneath cavities with a RDT below 0.25 mm; however maximal reactionary dentin appeared to be beneath cavities with an a RDT between 0.5-0.25 mm (P= 0.0001). The area of reactionary repair was also influenced by the choice of restoration material (P= 0.0385) from greatest to least; calcium hydroxide, composite, resin-modified glass-ionomer cement and zinc oxide-eugenol. Odontoblast numbers were maintained beneath cavities with a RDT above 0.25 mm, cavities placed closer to the pulp appeared to injure underlying odontoblasts, reducing their numbers (P= 0.0001). The choice of cavity restoration material also influenced the survival of underlying odontoblasts (P= 0.0061).

Acid Etching, Dental↗

PubMed2002

Histomorphometric analysis of dentinal bridge formation and pulpal inflammation.

OBJECTIVE: The purpose of this study was to evaluate pulpal responses to the use of four resin composite materials as direct pulp capping agents. The importance and effects of individual pulp capping variables are not well understood; consequently histomorphometric analysis was used to analyze these variables. METHOD AND MATERIALS: Two hundred fifty standardized pulp-exposed cavities were prepared in nonhuman primate teeth. Exposed pulps were capped with calcium hydroxide and multistep and self-etching primer resin composites. Teeth were collected from 3 to 60 days to observe pulpal reactions. Following perfusion fixation, tissues were demineralized, sectioned, stained, and histomorphometrically measured. Bridge area, diameter of pulpal exposure, and cavity floor width were measured. Tunnel defects, operative debris, and pulpal inflammation were graded according to defined criteria. RESULTS: The variables correlated to dentinal bridge area were, in decreasing order of significance, time elapsed since exposure, diameter of pulpal exposure, pulp capping material, and tunnel defects. The variables correlated to pulpal inflammation were the type and curing of pulp capping material. Other variables were not statistically significant. CONCLUSION: Pulp capping with resin composite materials provided acceptable pulpal inflammatory and dentinal bridge repair responses, comparable with those of calcium hydroxide. Although resin composites are promising as direct pulp capping agents, further investigations are required to optimize their application protocols to reduce the penetration of potentially cytotoxic monomers into pulpal tissue.

Acid Etching, Dental↗

PubMed2002

Hierarchy of pulp capping and repair activities responsible for dentin bridge formation.

PURPOSE: The importance of pulp capping variables which mediate pulp repair activities and dentin bridge formation following pulp exposure are not well understood. Consequently, the aim of this study was to investigate the effects of pulp capping variables on tertiary dentin bridge formation. MATERIALS AND METHODS: Calcium hydroxide [Ca(OH)2], resin-modified glass-ionomer (RMGI) and resin-based composite (RBC) were used to restore pulp exposures prepared in 161 nonhuman primate teeth, according to ISO usage guidelines. Teeth were collected from between 7 and 720 days to observe the pulp repair activities leading to dentin bridge formation. Bacteria were detected using McKays stain. Pulp activity was categorized histomorphometrically using ISO standards, and analyzed statistically using ANOVA statistics. RESULTS: The pulp capping variables in order of their relationship to dentin bridge area, from the most important to the least important were: time elapsed since pulp capping (P = 0.0009), pulp capping materials (P = 0.0252), bacterial microleakage (P = 0.0358) and area of operative debris in the dentin bridge (0.0362). A further 10 pulp capping variables were found to be less important. Relationships between pulp capping materials, operative debris, tunnel defects, bacterial microleakage, inflammation and dentin bridge formation were observed. Bacteria contaminated 18.6% of RBC, 22.2% of RMGI and 47.0% of Ca(OH)2 capped pulps.

Analysis of Variance↗