Marcelo Rodrigues Azenha

Bone response to biosilicates® with different crystal phases

The aim of this study was to investigate the histological and histomorphometrical bone response to three Biosilicates with different crystal phases comparing them to Bioglass 45S5 implants used as control. Ceramic glass Biosilicate and Bioglass 45S5 implants were bilaterally inserted in rabbit femurs and harvested after 8 and 12 weeks. Histological examination did not revealed persistent inflammation or foreign body reaction at implantation sites. Bone and a layer of soft tissue were observed in close contact with the implant surfaces in the medullary canal. The connective tissue presented few elongated cells and collagen fibers located parallel to implant surface. Cortical portion after 8 weeks was the only area that demonstrated significant difference between all tested materials, with Biosilicate 1F and Biosilicate 2F presenting higher bone formation than Bioglass 45S5 and Biosilicate vitreo (p=0.02). All other areas and periods were statistically non-significant (p>0.05). In conclusion, all tested materials were considered biocompatible, demonstrating surface bone formation and a satisfactory behavior at biological environment.

Evaluation of Crystallized Biosilicate in the Reconstruction of Calvarial Defects.

IntroductionThe objective of this study was to assess the bone repair process of crystallized Biosilicate in surgically created defects on rats’ calvaria. This biomaterial was recently developed for odontological use.Materials and methodsWe used fifteen rats (rattus norvegicus albinus, Wistar), and two 5 mm surgical defects were performed on each of them; the defects were made with trephine drill on the calvarium region prior to the biomaterial placement. Groups were divided as follows: Group 1—defect filled with clot; Group 2—defect filled with crystallized Biosilicate. After 7, 14 and 28 days the animals were killed, the parts were retrieved and slides were prepared for histological studies. ResultsBone formation was satisfactory in all groups, with direct contact between biomaterial surface and bone and absence of infection signs. The 28 days periods showed better results, and statistically significant difference between Clot Group (90.2 %) and Biosilicate (58 %; p = 0.002) was seen, regarding presence of bone tissue on the surgical defects.ConclusionOur study revealed that defects filled with clot present better results on bone formation compared to crystallized Biosilicate, which is considered a biocompatible material with favorable osteoconductive properties.

Retained Third Molars Removal in a Severely Resorbed Edentulous Mandible. A Case Report

The presence of asymptomatic third molars can represent a potential problem in the mandible when these teeth are retained and the patient has lost all normally erupted teeth. Once the mandibular first and second molars are removed, the mandibular body becomes weaker with time, increasing the complexity, morbidity and incidence of complication in the surgical procedure to remove the retained third molar. This paper reports a case where the mandibular third molars retained in a severely resorbed mandible were removed in a 54-year-old female patient. The treatment plan was based on the safe surgical removal of the teeth and prosthetic rehabilitation with an implant-supported milled bar overdenture and a bone-mucous-supported complete denture in the mandibular and maxillary arch, respectively. If the removal of a retained third molar is indicated in a severely resorbed edentulous mandible, the treatment plan must involve not only preventive measures in order to avoid mandible fracture during or after tooth removal, but also alternatives that allow an adequate mandibular rehabilitation.