The Role of Marine Organic Extract in Bone Regeneration: A Pilot Study.

Novel biomaterials capable of accelerating the healing process of skeletal tissues are urgently needed in dentistry. The present in vivo study assessed the osteoconductive and osteoinductive properties of experimental biphasic bioceramics (HA-TCP) modified or not by a nacre extract (marine organic extract, MOE) in a sheep model. Fabrication of MOE involved mixing ground nacre (0.05 g, particle sizes < 0.1 mm) with glacial ethanoic acid (5 mL, pH 7) for 72 hours using external magnetic stirring (25°C). Nonreactive carriers (sterile polythene tubes; 3/animal, radius: 2.5 mm, length: 10.0 mm) pertaining to the control (empty) or experimental groups (HA-TCP or MOE-modified HA-TCP) were implanted intramuscularly into the abdominal segment of the torso in sheep (n = 8, age: 2 years, weight: 45 kg). Euthanization of animals was performed at 3 and 6 months after surgery. Tissues harvested were subjected to macroscopic and radiographic assessments. Specimens were then stained for histological analysis. Both control and experimental animals were capable of inducing the neoformation of fibrous connective tissue at both time points where superior amounts of tissue formation and mineralization were detected for experimental groups (unaltered (at 3 and 6 mos) and MOE-modified HA-TCP (at 3 mos)). Histological results, however, revealed that mature bone formation was only observed for specimens fabricated with MOE-modified HA-TCP in a time-dependent manner. The present study has successfully demonstrated the in vivo utility of experimental biphasic bioceramics modified by MOE in an ectopic grafting sheep model. Promising osteoconductive and osteoinductive properties must be further developed and confirmed by subsequent research.

Pneumatization within a maxillary sinus graft: a case report.

Rehabilitation of edentulous posterior maxilla with implant-supported prostheses frequently presents a challenge to dentists. This is due to insufficient bone within the region, in addition to other limiting factors such as anatomical pneumatization of the maxillary sinus. Thus, grafting of the maxillary sinus is a common procedure used to counteract these problems. Regardless of the type of biomaterial used, the success of the procedure is dependent on the formation of high-quality bone. Therefore, vascularization is a key factor for successful grafting and for the long-term maintenance of the treatment. This paper reports a clinical case of bone graft pneumatization and attempts to elucidate its potential etiology.

Radiographic and histological evaluation of ectopic application of deproteinized bovine bone matrix.

OBJECTIVE: To evaluate, through radiographic and histological analysis, the tissue reaction induced by a biomaterial based on deproteinized bovine bone matrix (DBBM) in the muscle of sheep. MATERIALS AND METHODS: Sixteen sheep were used. The animals underwent surgery to insert polyethylene tubes containing the biomaterial in the muscle of the lower back (ectopic site) and were euthanized after 3 and 6 months. Each sheep received three tubes: Group 1 - sham group (negative control - tube without biomaterial), Group 2 - particulate autogenous bone (positive control), and Group 3 - DBBM biomaterial (GenOx Inorg). The material removed was evaluated by radiographic, macroscopic, and microscopic analysis, descriptively. RESULTS: Macroscopic analysis showed that Group 3 had a greater tissue volume maintenance. Microscopic analysis indicated that Group 1 had a higher concentration of dense, thin collagen fibers (3 and 6 months); in Group 2, there was a decrease in the inflammatory process and the deposition of dense, thin collagen fibers (3 and 6 months); in Group 3, the presence of a dense connective tissue was noted, in which the DBBM particles (3 months) were found. On the periphery of these particles, a deposition of basophilic material was found, indicating the formation of mineral particles and the formation of tissues with osteoid characteristics (6 months). CONCLUSION: Based on the results obtained, it can be concluded that the biomaterial based on DBBM led to the formation of tissue with similar characteristics to an osteoid matrix in a postoperative period of 6 months. However, none of the groups evaluated showed ectopic bone neoformation.

Effect of alendronate on the progression of periodontitis induced by Porphyromonas gingivalis and Fusobacterium nucleatum: a study in rats.

OBJECTIVE: The study aimed to investigate the effect of alendronate (ALN) on the inhibition of alveolar bone loss in experimental periodontitis in Wistar rats. MATERIALS AND METHODS: Periodontitis was induced by oral inoculation of Porphyromonas gingivalis with Fusobacterium nucleatum. The rats (n = 80) were randomized as follows: negative control (n = 10); positive control (n = 10); ALN groups: test 8 (n = 10), test 12 (n = 10), and test 16 (n = 10); and placebo groups: control 8 (n = 10), control 12 (n = 10), and control 16 (n = 10). Two milligrams per kilogram of ALN or placebo was administered twice weekly for 8, 12, and 16 weeks. Bone loss was determined by morphological and histological analyses. One independent, blinded examiner (ICC, 0.91) performed the measurements. The distance from the cement enamel junction to the alveolar bone crest of the second lower molar was measured: distal-vestibular (d), furca (f), mesial-vestibular (h), and area. Histometry was performed on the second contralateral molar. Sections (6 µm) were used to determine the furcation bone area (A-FB). The following statistical analyses were conducted: Mann-Whitney and Kruskal-Wallis. RESULTS: PC group developed periodontitis (p < 0.0001). Morphometric analysis determined that ALN was effective in T8 for linear measurements d, f, and h (p < 0.05). No significant differences occurred at test 8, test 12, and test 16. Analysis of A-FB revealed no significant differences between the ALN and placebo groups at 8 and 16 weeks (p > 0.05). ALN was effective against bone loss in relation to A-FB after 12 weeks (p < 0.0001). CONCLUSIONS: According to the methodology used, the results suggest that oral administration of ALN could influence alveolar bone loss in rats submitted to experimental periodontitis. CLINICAL RELEVANCE: ALN could be a potential therapeutic approach when associated with periodontal treatment.

Leukocyte-platelet-rich plasma (L-PRP) impairs the osteoconductive capacity of the autograft associated to changes in the immunolocalization of TGF-ß1 and its co-expression with Wnt10b and CD34 cells.

BACKGROUND: This study evaluated the osteoconductive effect of an autograft, in the presence or absence of the L-PRP, using histomorphometric analysis of the bone formed, and we compared the results in the presence of TGF-ß1, Wnt10b and CD34 detected by immunohistochemistry. MATERIALS AND METHODS: Two bone defects were produced in the calvaria of 20 rabbits. The defects were treated with autograft and autograft combined with L-PRP. The animals were euthanized at 15 and 40 days post-surgery. Data were analyzed by Student-Newman-Keuls (p ≤ 0.05) test for histomorphometric and immunohistochemical interpretation. RESULTS: The results revealed that the presence of bone matrix was significantly less in the defects treated with L-PRP. These results coincided with changes of the immunolocalization of the TGF-ß1. In the L-PRP-free groups the TGF-ß1 was restricted to bone matrix while the CD34 was scarce and the Wnt10b occurred in peritrabecular cells. In contrast, in defects that received L-PRP the presence of TGF-ß1 occurred in cells, which occupied whole area of defect. These TGF-ß1+ cells also were co-expressed to Wnt10b and CD34. CONCLUSION: These results suggest that L-PRP induces a cross-reaction between TGF-ß1 and Wnt10b, which stimulates the self-renewal and maintenance of CD34+ stem cells immunophenotype, impairing the osteoconductivity properties of the autograft.