Histologic Examination of Teeth with Necrotic Pulps and Periapical Lesions Treated with 2 Scaffolds: An Animal Investigation

•The aim was to histologically compare the tissues generated when PRP or a blood clot with Gelfoam is placed into teeth with preexisting necrotic pulps and periapical lesions.•Using scaffolds of PRP or blood clots resulted in more apical narrowing and hard tissue deposition versus when not using a scaffold.•The use of PRP or blood clots as scaffolds results in the ingrowth of bone-like, cementum-like, and connective tissue in the apical third of the roots at inconsistent rates.

IntroductionTraditional pulp regeneration procedures that use a blood clot as a scaffold have produced histologic evidence of bone, cementum, and connective tissue growth within the root. Platelet-rich plasma (PRP) is a bioactive scaffold containing growth factors that enhance wound healing.AimThe aim of this study was to histologically compare the tissues generated when PRP or a blood clot is placed into teeth with preexisting necrotic pulps and periapical lesions.MethodsTwenty-four canine teeth from 6 immature ferrets were used. Two ferrets served as positive controls. Sixteen experimental canine teeth from 4 ferrets were infected, debrided, treated with a triple antibiotic paste, and randomly distributed to the following groups: group 1 (blood clot/Gelfoam), group 2 (PRP), and group 3 (no scaffold). At 3 months, the ferrets were sacrificed, and the tissues were evaluated histologically. Data were analyzed by using the Fisher exact test (P < .05).ResultsIn 3 of 6 teeth in the PRP group, 2 of 6 teeth in the blood clot group, and 1 of 4 teeth in the no scaffold group, an ingrowth of hard tissues was observed in the apical third of the roots. When using PRP or a blood clot as a scaffold, we found significantly more apical narrowing and hard tissue deposition in comparison to not using a scaffold (P < .05).ConclusionsThe use of PRP or blood clots as scaffolds results in the ingrowth of bone-like, cementum-like, and connective tissue in the apical third of the roots at inconsistent rates.