Abstract
This histologic study aimed to measure the morphometric and morphologic changes in periodontal tissue after immediate and delayed mineral trioxide aggregate (MTA) repair of 2 sizes of furcal perforations.
There were 72 premolars from 12 beagle dogs that were divided equally into 4 experimental and 2 control groups (n = 12). Experimental groups included immediate small (0.6 mm in diameter), immediate large (1.8 mm in diameter), delayed (30 days) small, and delayed large furcal perforation MTA repair. The control groups included negative (no furcal perforation) and positive (nonrepaired small and large furcal perforations) controls. After 3 months, tissue blocks were harvested and processed for histologic assessment. Morphometric analysis measured the thickness of periodontal ligaments (average, maximum, and minimum) in millimeters, the area of interest in square millimeters, and the area of healing tissue at the perforation site in square millimeters. Morphologic assessment consisted of 7 parameters for tissue inflammation, resorption, and repair. Histologic assessment was completed by 2 calibrated examiners who were blinded to the study group.
Morphometric and morphologic measurements showed no significant difference between immediate and delayed MTA repair of small perforations and the negative control. The average thickness of the periodontal ligaments in delayed large perforations was 0.467 mm, which was significantly different from 0.294 mm in the delayed small perforations repair. The area of healing tissue in the positive control was 0.473 mm2, which was significantly different from 0.311 mm2 in delayed large perforation repair.
Within the study limitations, periodontal tissue responded more favorably to MTA repair of furcal perforation when it was placed in smaller perforations. The time of treatment became more critical as the perforation size increased.
•Histologic evidence that mineral trioxide aggregate (MTA) repair of smaller perforation is associated with new cementum formation and organized periodontal ligament (PDL) 30 days after perforation.•Time is a significant factor in larger perforations.•Delayed MTA repair of large perforations is associated with a favorable PDL response compared with nonrepaired perforations.