Pleiotropic effect of intramucosal injection of FTY720 on angiogenesis and tissue healing after free gingival graft surgery: a comparative experimental study in rabbits.

OBJECTIVES: Free gingival graft surgery is the gold standard for increasing the size of keratinized tissue. Blood supply in the recipient site is critical for healing. Therefore, in this study, the effect of FTY720 on angiogenesis, healing, and scar tissue presence following free gingival graft surgery is investigated. MATERIALS AND METHODS: Surgeries were performed on 10 New Zealand white rabbits. Rabbits were randomly assigned to two groups. In the experimental group, immediately after surgery, 2 and 4 days later, FTY-720 was injected into the tissue surrounding the recipient site. In the control group, the same frequency of placebo vehicle was injected. After 30 days, tissue samples were assessed histologically and histomorphometrically. RESULTS: The blood vessel count (P < 0.000) and rete ridge formation (P < 0.05) in the experimental group were significantly higher, while the epithelial thickness was lower in this group (P < 0.000). There was no significant difference in the percentage of regions occupied by collagen fibres between the groups (P = 0.987). Furthermore, a significant and negative relationship between epithelial thickness and blood vessel count was shown (Pearson correlation coefficient = - 0.917). CONCLUSIONS: The findings indicate that the angiogenic effects of FTY-720 in the recipient site of free gingival graft can be employed to promote tissue healing and reduce scar tissue presence. CLINICAL RELEVANCE: A significant decrease in epithelial thickness and increase in angiogenesis as well as rete ridge formation score in the FTY-720 group were shown, which can be translated into improved tissue healing and less presence of scar tissue.

The Effect of Low-Level Laser Therapy in Combination with Leukocyte- and Platelet- Rich Fibrin on Bone Regeneration in Rabbits' Calvarial Defects: Histologic and Histomorphometric Studies.

Objective: Bone regeneration is a desired treatment outcome in implant dentistry. The primary goal of the current investigation was to assess the joint effect of low-level laser therapy (LLLT) and leukocyte- and platelet-rich fibrin (PRF) on new bone formation. Materials and Methods: During this experiment study, forty bone defects (8 mm in diameter) were generated in the calvaria of ten New-Zealand white rabbits. defects were filled with autogenous bone defined as the control group, autogenous bone with leukocyte- and PRF (PRF group), autogenous bone and low-level diode laser radiation (LLLT group), and autogenous bone with leukocyte- and PRF and low-level laser radiation (LP group). Laser irradiation was done every second day for 2 weeks after surgery. Five rabbits were randomly selected to be sacrificed on postoperative weeks 4 and 8. On one and two-month post-surgery, histological and histomorphometric parameters including bone formation, fibroblast, and osteoblast were assessed. Results: The histological panel depicted that the ratio of fresh bone formation increased at one-and two-month postsurgery in all treatment groups compared to the control group. The most favorable results were seen in the LP group, followed by the PRF group. Based on the ANOVA test, bone neoformation was statistically significant in the LP group in comparison with the control group (P<0.001). One-month post-surgery, a higher degree of fibroblast was seen in the control group, while the last place was for LP group (118.6 ± 6.9 vs. 24.0 ± 3.2). In the PRF group, the percentage of bone formation was higher than that in the control group (13.2 ± 2.8 vs. 2.0 ± 1.2), but no significant difference when compared to the LP group (13.2 ± 2.8 vs. 19.0 ±.3.8). Conclusion: The combined L-PRF and LLLT was more likely to have a positive effect on accelerating bone regeneration and reducing fibrosis.

A collagen-based hydrogel containing tacrolimus for bone tissue engineering.

Bone tissue engineering aims to develop bone graft structure that can heal bone defects without using autografts or allografts. The current study was conducted to promote bone regeneration using a collagen type I hydrogel containing tacrolimus. For this purpose, different amounts of tacrolimus (10 µg/ml, 100 µg/ml, and 1000 µg/ml) were loaded into the hydrogel. The resulting drug-loaded hydrogels were characterized for their porosity, swelling capacity, weight loss, drug release, blood compatibility, and cell proliferation (MTT). For functional analysis, the developed hydrogel surrounded by a film made of gelatin and polycaprolactone (PCL) was administrated in the calvarias defect of Wistar rats. The results indicated that the hydrogel has a porosity of 89.2 ± 12.5% and an appropriate swelling, drug release, and blood compatibility behavior. The in vitro results indicated that the collagen hydrogel containing 1000 µg tacrolimus was adequate in terms of cell proliferation. Finally, in vivo studies provided some evidence of the potential of the developed hydrogel for bone healing.

Prevalence and location of the posterior superior alveolar artery using cone-beam computed tomography.

PURPOSE: Insufficient knowledge of the anatomy of the maxillary sinuses prior to sinus graft surgery may lead to perioperative or postoperative complications. This study sought to characterize the position of the posterior superior alveolar artery (PSAA) within the maxillary sinuses using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: A total of 300 patients with edentulous posterior maxillae, including 138 females and 162 males with an age range of 33-86 years, who presented to a radiology clinic between 2013 and 2015 were enrolled in this retrospective cross-sectional study. The distance from the inferior border of the PSAA to the alveolar crest according to the residual ridge classification by Lekholm and Zarb, the distance from the PSAA to the nasal septum and zygomatic arch, and the diameter and position of the PSAA were all assessed on patients' CBCT scans. The data were analyzed using the Mann-Whitney test and the t-test. RESULTS: The PSAA was detected on the CBCT scans of 87% of the patients; it was located beneath the sinus membrane in 47% of cases and was intraosseous in 47% of cases. The diameter of the artery was between 1 and 2 mm in most patients (72%). The mean diameter of the artery was 1.29±0.39 mm, and the mean distances from the PSAA to the zygomatic arch, nasal septum, and alveolar crest were 22.59±4.89 mm, 26.51±3.52 mm, and 16.7±3.96 mm, respectively. CONCLUSION: The likelihood of detecting the PSAA on CBCT scans is high; its location is intraosseous or beneath the sinus membrane in most patients. Determining the exact location of the PSAA on CBCT scans preoperatively can help prevent it from being damaged during surgery.

Prevalence, Location, and Size of Maxillary Sinus Septa: Computed Tomography Scan Analysis.

INTRODUCTION: The present study was undertaken to evaluate the anatomy of the maxillary sinus in relation to its position and the height of its septa, using cone beam computed tomography (CBCT). MATERIALS AND METHODS: In this descriptive retrospective study, 300 CBCT images of maxillary sinuses of patients with posterior maxillary edentulism were evaluated. The maxillary sinus septa were evaluated in relation to their prevalence, height, and position; t-test and Mann-Whitney tests were used for the analysis of data. RESULTS: Sinus septa were detected in 44% of the subjects, with equal frequencies in the anterior, middle, and posterior positions. The mean height of the septa was 3.6 ± 1.56 mm. CONCLUSION: In a population of Iranian subjects, in half of the cases, the sinus septa might be present in the anterior, middle, and posterior positions. CLINICAL SIGNIFICANCE: In order to avoid intraoperative problems during sinus lift procedures, it is necessary to accurately evaluate the sinus, preferably with the use of CBCT Keywords: Cone beam computed tomography, Dental implant, Maxillary sinus septa.