Jonas Dantas Batista

Enxerto bovino orgânico associado ao PRP em calvária de coelhos

INTRODUCTION: The osseous repairing in big imperfections is a great challenge for the restored surgery in nowadays. OBJECTIVE: The objective of this study was to make an histological evaluation of the osseous restore in rabbits calvaria after the bovine osseous grafts (Gen-ox-organic®) usage associated with plasma rich in platelet (PRP). METHOD: It was used 12 rabbits and 02 osseous fragments were removed from bilaterally calvarium. So among 24 surgical sites were randomly, divided in 03 groups: coagulum (group I), organic (group II) and organic with PRP (group III). After 04 weeks the animals were sacrificied and the grafted area was removed, fixed in formaldehyde at 10% in PBS 0,1M and included in paraffin. RESULTS: The histologic parameters analysed were: imperfection area filled up with neoformed, gigantic cells and grafts particles, and osseous neoformation associated with the particles. The groups I imperfections were filled up with fibrous tissue that conditioned the periosteum and presented a small osseous formation in the perimeter. In groups II and III, a similar pattern was observed and also with grafts particles and gigantic cells absence. There was no significative difference in gigantic cells, grafts particles and neoformations numbers around the particles between the grafted material and the group with PRP associated. CONCLUSION: The obtained results show that the isolated organic biomaterial or in association with PRP did not improve the osseous regeneration.

The Effect of Local Delivery Doxycycline and Alendronate on Bone Repair

The aim of the present study was to investigate the local effect of 10% doxycycline and 1% alendronate combined with poly(lactic-co-glycolic acid) (PLGA) on bone repair. Thirty rats were divided into three groups, as follows: control group (CG), drug group (DG), and vehicle-PLGA group (VG). Bone defect was created in the right femur and filled with the following: blood clot (CG); PLGA gel, 10% doxycycline and 1% alendronate (DG); or vehicle-PLGA (VG). The animals were euthanized 7 or 15 days after surgery. Bone density, bone matrix and number of osteoclasts were quantified. At 7 days, the findings showed increased density in DG (177.75 ± 76.5) compared with CG (80.37 ± 27.4), but no difference compared with VG (147.1 ± 41.5); no statistical difference in bone neoformation CG (25.6 ± 4.8), VG (27.8 ± 4), and DG (18.9 ± 7.8); and decrease osteoclasts in DG (4.6 ± 1.9) compared with CG (26.7 ± 7.4) and VG (17.3 ± 2.7). At 15 days, DG (405.1 ± 63.1) presented higher density than CG (213.2 ± 60.9) and VG (283.4 ± 85.8); there was a significant increase in percentage of bone neoformation in DG (31.5 ± 4.2) compared with CG (23 ± 4), but no difference compared with VG (25.1 ± 2.9). There was a decreased number of osteoclasts in DG (20.7 ± 4.7) and VG (29.5 ± 5.4) compared with CG (40 ± 9.4). The results suggest that the association of 10% doxycycline and 1% alendronate with PLGA-accelerated bone repair.

High doses of ionizing radiation on bone repair: is there effect outside the irradiated site?

Local ionizing radiation causes damage to bone metabolism, it reduces blood supply and cellularity over time. Recent studies indicate that radiation promotes biological response outside the treatment field. The aim of this study was to investigate the effects of ionizing radiation on bone repair outside the irradiated field. Ten healthy male Wistar rats were used; and five animals were submitted to radiotherapy on the left femur. After 4 weeks, in all animals were created bone defects in the right and left femurs. Seven days after surgery, animals were euthanized. The femurs were removed and randomly divided into 3 groups (n=5): Control (C) (right femur of the non-irradiated animals); Local ionizing radiation (IR) (left femur of the irradiated animals); Contralateral ionizing radiation (CIR) (right femur of the irradiated animals). The femurs were processed and embedded in paraffin; and bone histologic sections were evaluated to quantify the bone neoformation. Histomorphometric analysis showed that there was no significant difference between groups C (24.6±7.04) and CIR (25.3±4.31); and IR group not showed bone neoformation. The results suggest that ionizing radiation affects bone repair, but does not interfere in bone repair distant from the primary irradiated site.

The effects of ionizing radiation on the growth plate in rat tibiae

The deleterious effects of ionizing radiation on the growth plate continue to be cause for concern. This study evaluated the ionizing radiation effects on bone development and growth plate in the tibia of rats. All animals were submitted to ionizing radiation on the left leg. The animals were divided into two groups and euthanized 30 and 60 days after radiation. The tibiae were removed and separated into groups: control 30 days, irradiated 30 days, control 60 days and irradiated 60 days. Animals in each group (n = 7) were used for macroscopic and histological analysis. The irradiated tibiae showed arrested growth, angular deformity and limb length discrepancy when compared with nonirradiated tibiae. There was statistical difference between control and radiation groups in all the parameters analyzed, except in the lateral‐medial thickness of the distal epiphysis. Histological analysis showed evident changes in the growth plate, which was thicker in the Groups irradiated for 30 days, and irradiated for 60 days, compared with their respective controls. The growth plate showed wide areas with disorganized zones of chondrocytes and severely reduced calcification zone. It was concluded that ionizing radiation damaged the growth plate, compromised the endochondral ossification process, and resulted in complete arrest of bone development.

Reconstruction of Mandibular Defects

Surgical reconstruction of mandibular bone defects is a routine procedure for rehabilitation of patients with deformities caused by trauma, infection or tumor resection. The mandible plays a major role in masticatory and phonetic functions, supporting the teeth and defining the contour of the lower third of the face. Therefore, mandibular discontinuity produces se‐ vere cosmetic and functional deformities, including loss of support for suprahyoid muscles and subsequent airway reduction. Reconstruction of these severe defects is mandatory for restoring the patient’s quality of life. Surgical techniques have improved considerably in the last decade, but reconstruction of large bone defects of the mandible still pose a great chal‐ lenge in maxillofacial rehabilitation. Several things can be done to optimize the surgery; the use of prototyping modeling for instance provides a better assessment of the bone defect and pre-contouring of the fixation plates, reducing operating time. The choice of the most suitable titanium plate system is critical to the success of the procedure. Mandibular defects with loss of continuity require more robust (load bearing) systems supporting mandibular function. Many studies consider the use of plates and screws temporary treatment due to the large number of complications such as fracture of plates and screws, plate exposure and infection. Thus, the use of grafts both in the first operation or in a two-stage procedure en‐ sures a more predictable result.