Histologic and Histomorphometric Assessment of Xenograft Bone Substitute versus Synthetic Nonceramic Hydroxyapatite for Canine Tooth-Socket Preservation.

This study sought to histologically and histomorphometrically assess and compare application of xenograft bone substitute and synthetic nonceramic hydroxyapatite for tooth-socket preservation in dogs. This split-mouth clinical trial was conducted in five hybrid dogs, using four tooth sockets in each dog, with a total of 20 sockets for evaluation. Group 1 received xenografts, and group 2 received synthetic nonceramic hydroxyapatite in the sockets. In group 3 (positive controls), sockets remained empty. All sockets were covered with collagen resorbable membrane, and the flap was stitched using nonresorbable sutures. In group 4 (negative control), sockets were without membrane, left empty, and sutured. After 12 wk, 8-mm-high bone core biopsies were harvested from inside the sockets, using a trephine bur with an internal diameter of 2 mm. We assessed the tissue in terms of percentage of newly formed viable bone, percentage of remaining particles, degree of inflammation, and type of connective tissue. Data were statistically analyzed. The percentage of newly formed viable bone was 34.98% in group 1 and 41.30% in group 2, and this difference was not statistically significant (p = 0.710). The percentage of remaining particles was 15.95% in group 1 and 14.14% in group 2; this difference was also not statistically significant (p = 0.902). Both synthetic nonceramic hydroxyapatite and xenograft bone substitute showed similar efficacy, histologically and histomorphometrically, when used with resorbable collagen membrane for tooth-socket preservation in dogs.

Histological assessment of pulp condition after apical vital root transection in one root of multirooted teeth in dogs: a preliminary study.

One of the most important aspects in surgery is the healing process after the periapical surgery. Past studies have shown occasional encounters with vital root resection and have noted varying degrees of pulpal response after root resection in periodontal disease. The purpose of this investigation was to observe the pulpal and periapical responses to intentional apical vital root transection in one root of multirooted teeth of German-Canadian dogs over a 6-month postoperative period. This is an experimental study performed on left maxillary and mandibular quadrants of four adult German-Canadian dogs after a 3- and 6-month period. Four teeth were assessed in each interval. One of the roots of multirooted teeth in the left quadrant of both maxillary and mandibular jaws was surgically transected. Tissue blocks were prepared by routine histological methods after 12 and 24 weeks after the surgery. The results showed a disruption of the normal pulpal architecture, with initial pulpal degeneration and subsequent early replacement by the periodontal ligament tissue after 24 weeks. Hypercementosis was seen around the apical portion of the root in all specimens. Pulpal regeneration was seen in the both upper and lower molars (p = 0.03). Resorption took place only in two specimens (p = 0.46). The inflammation in the 12th week was more than the 24th week. The pulp of multirooted teeth remains vital after transection of the apical part of the root in dogs. Longer follow-up periods are recommended because root canal therapy or extraction is indicated if resorption, necrosis, or ankylosis is seen.