Evaluation of the biological effect of mineral trioxide aggregate in inflamed pulp-in vivo analysis.

The health of dental pulp tissue is critical to maintaining normal tooth function from the eruption of permanent teeth to the formation of the apex. The study evaluated the inflamed pulp response to the mineral trioxide aggregate (MTA) after direct pulp capping with the mechanical pulp exposure in rats' incisor. Forty-eight mandibular central incisors of twenty-four Sprague-Dawley rats which were prepared with the cavities of one mm diameter, and the pulp exposures were randomly assigned into two groups: MTA group and calcium hydroxide (Ca(OH)2) group. The direct pulp capping was performed after three days and samples histological observations conduction within eight weeks. In both MTA and Ca(OH)2 groups, dentin -like structures were observed in the pulp tissues of some teeth. The number of teeth with reparative tissue in MTA group was statistically significantly higher than that in Ca(OH)2 group (p = 0.041). Inflammatory cell infiltration was found in the crown pulp tissues in two groups, and no statistical difference was observed between the two groups (p = 0.243). Pulp necrosis occurred in both groups, and there was no statistical difference between the two groups (p = 0.622). The results in this paper suggest that MTA promotes direct pulp capping and hence has certain potential clinical applications value in the treatments for the preservation of inflamed pulp.

Root dilaceration in maxillary impacted canines and adjacent teeth: A retrospective analysis of the difference between buccal and palatal impaction.

INTRODUCTION: This research aimed to analyze the prevalence of root dilaceration in buccally impacted canines (BICs) and palatally impacted canines (PICs) with their adjacent teeth based on a retrospective cone-beam computed tomography (CBCT) investigation. METHODS: Pretreatment CBCT images of 145 subjects with unilateral maxillary canine impaction and 145 age- and sex-matched subjects without impaction were used. Prevalence of dilaceration (subclassified to root curvature and apical hook based on severity) in canines and adjacent teeth was determined in CBCT records. The root length of maxillary impacted canines was measured for further morphologic evaluations. RESULTS: Impacted canines had a significantly higher prevalence of root dilaceration than the control group and compared with the erupted contralateral canines in the experimental group (P < 0.001 for both). A significantly higher prevalence of root dilaceration was found in adjacent lateral incisors of the PICs subgroup than that of the control group (P < 0.001). Adjacent premolars had a higher prevalence of dilacerated roots in the PICs subgroup (P < 0.001) than the control group, but not for the BICs subgroup. Significantly higher prevalence of curvature (P < 0.001 for both) and hook (P = 0.008 and P < 0.001, respectively) were found in BICs and PICs roots compared with the control group. Both types of impacted canines had significantly shorter roots than the control group (P < 0.001 for both). CONCLUSIONS: BICs and PICs have a higher tendency to present root dilaceration and shorter roots. Unlike BICs, adjacent teeth to PICs were more frequently observed to have root dilaceration.