Viabilidade dos enxertos autógenos obtidos com a utilização de coletores para osso: estudo histológico e microbiológico

The use of autogenous bone grafts is considered to be the best choice for reconstructive surgery. In the periodontal literature, the utilization of osseous coagulum was suggested by the end of the sixties. The purpose of this study is to consider the use of bone collectors (bone traps) as an alternative method for obtaining material to fill small bone imperfections, such as fenestrations and dehiscences. Thirty samples were obtained from bone drilling during fixture installation in patients (13 men and 17 women, with an average age of 54 years) requiring treatment at the Department of Periodontology and Implant Dentistry, University of Santo Amaro. These samples were fixed in 10% neutral formaldehyde for 24 hours and subjected to histological preparation, in order to evaluate the presence of viable osteoblasts. In addition, the material was placed in a fluid thioglycolate medium and incubated for 24 hours at 36 ± 1°C in aerobiosis and anaerobiosis. Bacterial growth evaluation was made by using six different culture media (MacConkey agar, blood agar base, mannitol salt agar, Anaerokit LTD medium, Anaerokit LTD - bile medium, Anaerinsol). The results show that, if proper care is taken to prevent saliva contamination during the surgical procedure, this method of collecting autogenous bone may be useful in situations where small amounts of bone are required.A utilização de enxertos autógenos é considerada a melhor opção nos tratamentos cirúrgicos de reconstrução óssea. Na literatura periodontal, a utilização de coágulo ósseo foi sugerida no final da década de 60. O objetivo deste estudo é considerar a utilização de coletores para osso como um método alternativo de se obter osso autógeno para preenchimento de defeitos ósseos como fenestrações e deiscências. Trinta amostras foram obtidas no processo de perfuração do tecido ósseo, durante a instalação de implantes em pacientes (13 homens e 17 mulheres, com média etária de 54 anos) que foram submetidos a tratamento na Disciplina de Periodontia e Implantodontia da Universidade de Santo Amaro. Essas amostras foram fixadas em solução de formol neutro a 10% por 24 horas para serem analisadas histologicamente com o intuito de avaliar a presença de osteoblastos viáveis. Além das amostras fixadas, também foram obtidos espécimens que foram incubados em aerobiose e em anaerobiose, em meio de tioglicolato por 24 h a 36 ± 1°C. A avaliação do crescimento bacteriano foi feita através de seis meios seletivos de cultura (ágar MacConkey, ágar-sangue, ágar manitol, meio Anaerokit LTD, meio Anaerokit LTD - bile e Anaerinsol). Os resultados mostraram que, se forem tomados certos cuidados para prevenir a contaminação com saliva durante o procedimento cirúrgico, este método de coletar osso autógeno pode ser útil em situações em que pequenas quantidades de osso são necessárias

Fracture of abutment screw supporting a cemented implant-retained prosthesis with external hexagon connection: a case report with sem evaluation

One of the causes of implant failures in cemented implant-retained prostheses is the fracture of abutment screw or UCLA abutment. This article reports a case of simultaneous fracture of two UCLA abutments screws occurring in an implant-supported prosthesis placed in the mandibular molar region. The fractured structures were examined under scanning electron microscopy to investigate the probable causes of the failure, which were not related to failures on materials or fabrication of the screws, but rather were due to shear forces. The misfit in cemented prostheses may be the most likely cause of shear force generation

Infrared thermography comparison of heat generation between simplified and conventional implant site preparation techniques

ABSTRACT Introduction: The predictability of osseointegration depends on a non-traumatic surgical technique that maintains cell viability. It is known that during the drilling osteotomy for implant placement occurs heat generation, being able to influence osseointegration due to thermal damage. The objective of this research was to evaluate and compare the heat generated by the drills during the preparation of surgical sites for implant placement between two different techniques: simplified (Simplified Drilling, SD) and conventional, in an in vitro model. Material and methods: Fifty implant site preparations were performed in segments of bovine ribs, divided into two groups, with the respective drill sequences: control group, conventional preparation, Ø2.0mm spear drill and Ø2.15mm, Ø2.85mm, Ø3.35mm, Ø3.85mm twist drills; SD group, Ø2.15mm and Ø3.85mm twist drills. The measurement of the temperature variation generated by each drill in each group was performed by an infrared thermal camera at three points in the bovine rib segment. Results: The temperature variations at one and thirteen millimeters below the drilling site were, respectively, 0.51±0.64°C and 0.46±0.59°C for the control group, and 0.62±0.76°C and 0.5±0.86°C for the SD group. No statistically significant differences were found between the control and SD groups in relation to heat generation in any of the evaluated points; p=0.288 and p=0.584, respectively for analyzes one and thirteen millimeters below the drilling site. Discussion: The technique of implant site preparation can be simplified, using only two drills in this modality, without showing significant differences in relation to heat generation when compared to the conventional preparation technique

Horizontal Alveolar Ridge Augmentation in the Mandibular Posterior Region Using Biphasic Calcium Phosphate and Leukocyte- and Platelet rich fibrin (L-PRF): A case report.

In bone defects caused by tooth loss, tissue reconstructions are necessary to enable prosthetic rehabilitation with dental implants. Diverse techniques and materials of different origins are used for this purpose.  Leukocyte- and Platelet-Rich Fibrin (L-PRF) has been used in association with osteoconductive biomaterials in procedures of bone regeneration and for covering grafted areas. The aim of this article was to demonstrate a clinical case of bone grafting in the posterior region of the mandible, performed with the use of synthetic biomaterial composed of biphasic calcium phosphate associated with Leukocyte- and Platelet-Rich Fibrin for performing bone augmentation in an alveolar ridge with a horizontal defect, thereby enabling later installation of dental implants and prosthetic rehabilitation in the region. Keywords: bone graft, biomaterials, leukocyte- and platelet-rich fibrin, bone substitutes, dental implants.In bone defects caused by tooth loss, tissue reconstructions are necessary to enable prosthetic rehabilitation with dental implants. Diverse techniques and materials of different origins are used for this purpose.  Leukocyte- and Platelet-Rich Fibrin (L-PRF) has been used in association with osteoconductive biomaterials in procedures of bone regeneration and for covering grafted areas. The aim of this article was to demonstrate a clinical case of bone grafting in the posterior region of the mandible, performed with the use of synthetic biomaterial composed of biphasic calcium phosphate associated with Leukocyte- and Platelet-Rich Fibrin for performing bone augmentation in an alveolar ridge with a horizontal defect, thereby enabling later installation of dental implants and prosthetic rehabilitation in the region.

Factors associated with early and late failure of osseointegrated implant

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Periodontal clinical evaluation before and after surgically assisted rapid maxillary expansion

ABSTRACT Introduction: The surgically assisted rapid maxillary expansion is a procedure that reduces the resistance of the sutures correcting the posterior crossbite in adults. Objective: The aim of this study was to evaluate the periodontal status of 17 adults submitted to this procedure. Methods: The clinical attachment level (CAL), gingival recession, attached gingiva and bleeding were evaluated in maxillary first premolars and molars, central and lateral incisors of right and left sides before surgery, 5 days and 6 months after. Means, standard deviation, medians, minimum and maximum values were compared among the evaluations using the Friedman and McNemar tests. Results: There was a statistically significant increase in CAL in the right central incisor, right and left premolars and right and left molars. There was a statistically significant increase in gingival recession in the right and left premolars and molars. The amount of attached gingiva significantly decreased in right premolars and right and left molars. There was increase in bleeding in most of the teeth. Conclusion: Results indicated that the surgically assisted rapid maxillary expansion might cause alterations in periodontal tissue

Lateralization Technique and Inferior Alveolar Nerve Transposition

Bone resorption of the posterior mandible can result in diminished bone edge and, therefore, the installation of implants in these regions becomes a challenge, especially in the presence of the mandibular canal and its contents, the inferior alveolar nerve. Several treatment alternatives are suggested: the use of short implants, guided bone regeneration, appositional bone grafting, distraction osteogenesis, inclined implants tangential to the mandibular canal, and the lateralization of the inferior alveolar nerve. The aim was to elucidate the success rate of implants in the lateralization technique and in inferior alveolar nerve transposition and to determine the most effective sensory test. We conclude that the success rate is linked to the possibility of installing implants with long bicortical anchor which favors primary stability and biomechanics