Finite element evaluation of three methods of stable fixation of condyle base fractures

The surgical treatment of mandibular condyle fractures currently offers several possibilities for stable internal fixation. In this study, a finite element model evaluation was performed of three different methods for osteosynthesis of low subcondylar fractures: (1) two four-hole straight plates, (2) one seven-hole lambda plate, and (3) one four-hole trapezoidal plate. The finite element model evaluation considered a load applied to the first molar on the contralateral side to the fracture. Results showed that, although the three methods are capable of withstanding functional loading, the lambda plate displayed a more homogeneous stress distribution for both osteosynthesis material and bone and may be a better method when single-plate fixation is the option.

Spontaneous healing responses detected by cone-beam computed tomography of horizontal root fractures: a report of two cases

Horizontal root fractures (HRF) usually affect the anterior teeth as a result of trauma, and generally heal spontaneously, depending on the vitality of the pulp. Diagnosis based on clinical findings, sensitivity tests, and radiographic examination is important to determine the presence of a root fracture and to prevent a root fracture from passing unnoticed. Cone-beam computed tomography (CBCT) has been used successfully for diagnosis and prognosis imaging of root fractures and has proved to be superior to other radiographic methods. This study reports two cases of dental trauma caused by a collision and a sports accident. The patients suffered horizontal root fractures in the maxillary left central incisor and in the mandibular left central incisor. The diagnosis of root fracture was confirmed by cone-beam computed tomography (CBCT) images, which also demonstrated spontaneous healing of the fracture line. The repair occurred by interposition of connective tissue in the former case and by interposition of bone and connective tissue in the latter case. The final diagnoses of both cases were based on CBCT images, indicating the importance of a CBCT examination to reach a firm diagnosis and to follow the healing process of root fracture cases, avoiding unnecessary radical endodontic treatment.

Investigation of chemical changes in sealers during application of the warm vertical compaction technique

Aim To assess (i) heat generated by pluggers during warm vertical compaction of gutta-percha and investigation of temperature changes on the external root surface during canal filling, and (ii) the chemical changes of root canal sealers induced by heat.Methodology Four sealers, namely AH Plus, MTA Plus and two other experimental sealers based on tricalcium silicate, were characterised. External temperatures generated on the root surface during warm vertical compaction of gutta-percha with different sealers inside the root canal were monitored using an infrared thermography camera. Chemical changes induced by heating the sealers were assessed by Fourier transform infrared (FT-IR) spectroscopy.Results MTA Plus and the experimental sealers were composed of a cement and radiopacifier, with epoxy resin or a water-soluble polymer as dispersant, whilst AH Plus was epoxy resin-based. The heat generated at the tips of the continuous wave pluggers was found to be lower than the temperature set and indicated on the device LCD display. The sealers reduced the heat generated on the external root surfaces during the heating phase. AH Plus sustained changes to its chemical structure after exposure to heat, whilst the other sealers were unaffected.Conclusions The temperatures recorded at the tips of continuous wave pluggers varied with their taper and were lower than the temperature set on the System B LCD display. Root canal sealers reduced the dissipation of heat generated during warm vertical compaction, with the temperature at the external root surface maintained at 37-41 degrees C, a temperature below that is necessary to cause irreversible damage to bone and periodontium. The use of AH Plus sealer during warm vertical compaction techniques results in chemical changes in the sealer. The effect on sealer properties needs to be further investigated.

Análise da densidade óssea de rádio-ulna de cães SRD utilizando o método de imersão

Imaging diagnosis is a medical specialty that uses imaging techniques to perform diagnosis. In diagnostic imaging various methods are used such as direct absorption of photons - SPA and DPA, radiographic photometry, the dual-energy radiographic absorptiometry - DEXA, ultrasound, magnetic resonance imaging, computed tomography and optical densitometry in radiographic image. The dog can be considered one of the most widely used animals in the study of bone diseases and searching for a reliable diagnosis, although not an ideal model for the study of osteoporosis, because these animals tend not to develop a decrease in bone mineral density. The objective of this study was to analyze bone density in mongrel dogs from the determination of the variation of density along the radio-ulna bone and also the mean value related to gender, weight and age of individuals. The density analysis carried out showed that for this data set, there is a significant difference in the case of gender and age of the animal and may generalize according to these variables. The only significant difference was found in the weight, which increases bone mass is related to weight gain through the growth of the animal

Reparação de enxertos ósseos autógenos recobertos ou não por membrana de ptfe-e em ratas ovariectomizadas. Estudo histológico e histomorfométrico

Abstract : The objective of this study was to evaluate quantitatively and to describe qualitatively the process of bone repair in the interface of receptor bed and graft autogenous bone block with or without a e-PTFE membrane, in osteopenia induced rats. To this end, we used forty-eight Wistar rats weighing about 300g, in which, with the aid of 4.1 mm trephine a graft was removed from the parietal bone and fixed to the surface of the left mandibular ramus. The animals were randomly divided into four experimental groups: Group 1 (n=12): SHAM operated and autogenous bone graft only; Group 2 (n=12): SHAM and autogenous bone graft covered by e-PTFE membrane; Group 3 (n=12): ovariectomized rats (OVX) and autogenous bone graft only; Group 4 (n=12): OVX and autogenous bone graft covered by e-PTFE membrane. The animals in each group were sacrificed at three time periods: 21, 45 and 60 days, each time with 4 animals per group. The specimens were decalcified and included, the sections were stained with HE and subjected to histological and histomorphometric analysis in light microscopy. The results of the ANOVA showed that the variables on the condition (OVZ and SHAM), and the time (21, 45 and 60 days) were statistically significant, and can be established with the Tukey test (5%) that the period 21-day differs significantly from the periods of 45 and 60 days, which did not differ among themselves. The descriptive histological analysis showed integration of the graft in all animals. It was concluded that the initial integration of the graft bed was negatively affected in the presence of induced osteopenia, and that the use or not of a e-PTFE membrane did not interfere in the process of integration

Crescimento de apatita na superfície da liga Ti-25Ta empregando dois tipos de tratamento de superfície: biomimético e deposição de polímero por eletrofiação

Titanium and its alloys has been widely used as materials for metallic biomaterials implants are usually employed to restore the hard tissue function, being used for artificial joints and bones, synthetic plates, crowns, dental implants and screws . Objective of this work was the surface modification of Ti-alloy 25Ta from biomimetic surface treatment of employment and deposition of polymer by electrospinning. The league was obtained from the fusion of the pure elements in the arc furnace with controlled atmosphere. The ingots were subjected to heat treatment, cold forged and sectioned discs with 13 mm diameter and 3 mm thick. Two surface treatments was evaluated, biomimetic and electrospinning with PCL fiber. The biomimetic treatment was performed involving alkaline treatment for three molarities 1.5M, 3M and 5M with immersion in SBF. The electrospinning was performed using PCL polymer alloy surface after the alkali treatment Ti25Ta 1M. For this group the polymer coated surfaces were immersed in calcium phosphate containing solution for immobilization of apatite. The results were compared with previous studies using surface treatment group to verify hydroxyapatite formation on the sample surface and it is concluded that the best condition is biomimetic treatment with 5M alkali treatment and heat treatment at 80 ° C for 72 hours

Parâmetros genéticos para integridade óssea do fêmur e estudo da associação dos genes runx2 e tnfs11 em frangos de corte

Pós-graduação em Genética e Melhoramento Animal - FCAV

Desenvolvimento de parafuso de interferência bioabsorvível para cirurgia de joelho em PLDL (poli ácido lático) e compósito PLDL + βTCP (beta trifosfato de cálcio)

Pós-graduação em Engenharia Mecânica - FEB

Caracterização radiográfica ex vivo de biomateriais utilizados para regeneração óssea em mandíbulas de porcos

Introduction: The radiographic characteristics of a biomaterial, such as its density, may influence the evaluation of the results obtained following its clinical use. Objective: The aim of this study was to evaluate the radiographic density of biomaterials used as bone substitutes, inserted into dental sockets and bone defects in created in the jaws of pigs. The influence of a soft tissue simulator on the results was also evaluated. Material and method: Two and three-millimeter-deep bone defects were created in the pigs mandible and the right first molar extraction socket were used. Commercial samples of five biomaterials were tested: Hydroxyapatite, Lyophilized Bovine Bone, 45S5 bioglass (generic), PerioGlass and β-Tri-Calcium Phosphate, and compared to a positive (mandibular bone) and negative (empty alveolar bone defects) controls. Radiographic images were acquired with and without a 10 mm thick soft-tissue simulator. Result: The results for the extraction sockets showed no differences between the biomaterials and the negative control. For the bone defects, the depth of the defect density influenced the density, both in the negative control (p < 0.01) and biomaterials (p < 0.05) groups. The soft- tissue simulator did not alter the results. Conclusion: The type of the evaluated defect can interfere in the radiographic features presented by each biomaterial, while the simulation of soft tissues was not statistically significant.

Reabilitação total da maxila com enxerto intraoral: relato de caso

The early tooth loss and periodontal disease often leave inadequate bone volume for installation of osseointegrated implants. The autogenous bone graft is considered the gold standard for reconstruction of residual bone defects. Some surgical techniques can be performed, including extra or intraoral donor sites depending on the degree of bone loss, depending on surgical-prosthetic planning and general condition of the patient. The intraoral bone grafts offer a safe option to rebuilt bone volume in smaller rehabilitations, with low morbidity and minimal postoperative discomfort. Among the possible donor sites, the mandibular ramus and body, which offer predominantly cortical bone, and the chin area, which offers corticomedullary bone tissue, can be harvested. The graft will be suitable both in quantity and quality, preserving the capacity of osteogenesis, osteoinduction and osteoconduction, which differentiate autogenous grafts from other biomaterials. The aim of this study was to report a clinical case in which the mandibular ramus graft was used for total reconstruction of an edentulous maxilla, showing that even large areas can be reconstructed with grafts from intraoral origin. All the steps that allowed the complete reconstruction of the maxilla done by an intraoral donor area are listed in the text, culminating in an extremely satisfactory clinical result.

Uso de um distrator ósseo dentoimplantossuportado, feito a partir de tornos expansores convencionais, na reabilitação oral

Osteodistraction is a clinical reality, available in the last decades for the resolution of large bone deficiencies, in cases that there are pre-existing, but misplaced implants and teeth. The aims of thearticle is to present a case report in which a new possibility for bone distraction, based on tooth-implant bone distractors, made from standard orthodontic expansion-screws, was used in an area where there was an extensive need of alveolar bone and aesthetical recovery, allied to teeth and dental implant misplacement. This technique presented good clinical results, associated to effective simplicity and low cost, becoming viable clinical solution for bone tissue augmentation and aesthetical optimization. In resume, it is possible to say that the suggested technique achieved its objectives, improving the hard and soft tissue profile, whilst allowing completion of oral rehabilitation.

A utilização do enxerto ósseo autógeno para tratamento de lesão de furca grau II

Destruction of bone and periodontal ligament as a result of periodontal disease can lead to anatomical defects in the furcation area. Treatment of these lesions is a major challenge to the clinician. Periodontal instruments have limited access to this area and plaque and calculus removal from root surfaces are extremely difficult. For proper treatment planning a number of factors must be taken into consideration to achieve immediate and long term success. Surgical therapy associated with bone grafts may be a viable option in the treatment of class II furcation defects, aiming to restore lost tissues. The aim of this paper is to report a clinical case where a simplified surgical approach with the use of autogenous graft was used to treat a class II furcation defect Twelve months after the surgery, an increase in clinical attachment level and pocket depth reduction resulted in a complete closure of the furcation lesion.

Peripheral osteoma in the ramus of mandible: report of case

The osteomas are benign rare neoplasms, generally asymptomatic which are characterized by the proliferation of a compact or spongy bone. When they are situated in the maxillofacial area, they affect mainly the mandible, the frontal bone and the paranasal sinus. We have described the case of a female caucasian patient who presented an increased volume in the posterior region of the oral vestibule on the left side. During the clinical examination an oral lesion was observed in the region of the left ramus of mandible. This lesion was motionless, consistent, and painless when palpated. In the image obtained from the computed tomography cone–beam (CBCT), we could observe an hyperdense, cylindrical region, with well defined borders, located in the medial surface of the left ramus of mandible, right below the mandibular notch. Based on clinical data and in the obtained images, we could confirm the presence of the peripheral osteoma in the left side of the ramus of mandible region.

Scientific use of the finite element method in Orthodontics

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influência da obesidade sobre o tecido ósseo de Rattus novergicus albinus idosos, submetidos à suspensão pela cauda e ao exercício resistido

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)