Age-related Changes in the Alkaline Phosphatase Activity of Healthy and Inflamed Human Dental Pulp.

INTRODUCTION: Alkaline phosphatase (ALP) plays an important role in inducing mineralization events in the dental pulp. This study investigated and compared the ALP levels in healthy and inflamed pulp in young and old human pulp. METHODS: Tissue samples were collected from young (<30 years) and old (>60 years) donors. In both age groups, healthy human pulp (n = 18) were collected from extracted wisdom teeth. For reversible and irreversible pulpitis, pulp samples (n = 18 each) were obtained during endodontic treatment. ALP activity was assessed by spectrophotometry and immunhistochemistry. RESULTS: Regardless of age, reversible pulpitis group samples showed a slight elevation in ALP activity compared with normal healthy pulp. In elderly patients, ALP expression with irreversible pulpitis was significantly higher than those with a healthy pulp (P < .05). CONCLUSIONS: In the hyperemic state, both the young and old pulp shows a slight increase in ALP activity, whereas in irreversible pulpitis, only the old pulp shows significantly elevated ALP levels. Such an increase may trigger calcification events, which may eventually cause difficulties in endodontic treatment procedures in elderly individuals.

Effect of EDTA, sodium hypochlorite, and chlorhexidine gluconate with or without surface modifiers on dentin microhardness.

INTRODUCTION: This study aimed to evaluate the effects of root canal irrigants on the microhardness of root canal dentin in the presence and absence of surface-modifying agents. METHODS: Forty-eight root halves were prepared by longitudinal splitting of the distal roots of 24 freshly extracted mandibular human third molars and embedded in autopolymerizing acrylic resin, leaving the dentin surface exposed. After polishing, the microhardness values of the untreated dentin surfaces were recorded by using Vickers tester at the mid-root level. The root halves were randomly assigned to 6 groups composed of 8 samples each and treated for 5 minutes with one of the following irrigants: 17% EDTA, REDTA, 2% chlorhexidine gluconate (CHX), 2% CHX with surface modifiers (CHX-Plus), 6% NaOCl, or 6% NaOCl with surface modifiers (Chlor-XTRA). After surface treatment, dentin microhardness values were recorded at close proximity to the initial indentation areas. Experimental data were statistically analyzed by using the t test and one-way analysis of variance, followed by Tukey honestly significant difference test at α = 0.05. RESULTS: EDTA, REDTA, NaOCl, and Chlor-XTRA significantly decreased the microhardness of root dentin compared with intact controls (P < .05). CONCLUSIONS: The addition of surface modifiers to the irrigants did not affect the microhardness of the samples.