Use of autologous micrografts associated with xenogeneic anorganic bone in vertical bone augmentation procedures with Barbell Technique®.

INTRODUCTION: Bidirectional vertical ridge augmentation in the posterior maxilla is very challenging. PURPOSE: To evaluate the regenerative potential of micrografts, derived from periosteum or bone tissue, added to an anorganic xenograft in vertical reconstruction of the posterior maxilla, by a prospective, controlled study. MATERIALS AND METHODS: After clinical selection and the analysis of CBCT scans, 24 posterior maxillary sites, in 19 patients, were treated by using Barbell Technique®. Sites requiring both inlay and onlay reconstruction were enrolled in the study. In the Control Group (CG, n = 8), a xenograft was used in the inlay site and for the onlay site, a 1:1 mix of xenograft and an autograft was used. In Test Group 1 (TG1, n = 8), both inlay and onlay sites were grafted with the xenograft associated with the micrografts derived from periosteum. In Test Group 2 (TG2, n = 8), both inlay and onlay sites were grafted with the xenograft associated with the micrografts derived from bone. Six months after the procedures, CBCT scans were obtained, and bone biopsy samples were harvested during implant placement surgery. The bone specimens were analyzed histomorphometrically, by measuring the percentages of vital mineralized tissue (VMT), non vital mineralized tissue (NVMT) and non mineralized tissue (NMT). Immunohistochemically, the levels of VEGF were categorized by a score approach. RESULTS: Histomorphometric analysis revealed, for the inlay grafts, no significant difference among the groups for VMT, NVMT and NMT. However, for onlay grafts, CG achieved a higher amount of VMT in comparison with TG2, and the opposite occurred for NMT values. In this regard, no statistical difference was observed between CG and TG1. Concerning immunohistochemistry, the VEGF values for CG and TG1 were slightly higher than those obtained by TG2 for both inlay and onlay grafts, but without statistical significance. CBCT analysis showed a similar level of gain for all groups, for both inlay and onlay bone augmentation sites. Clinically, one implant (in CG) within a total of 50 implants installed, had early failure and was replaced after 3 months. All patients received implant supported prosthesis. CONCLUSION: This study indicated that the clinical use of micrograft derived from periosteum may have some potential to increase bone formation in onlay reconstructions, unlike the micrograft derived from bone tissue.

Barbell Technique for Three-Dimensional Bone Augmentation.

Introduction: Appositional bone augmentation is considered a challenging surgical problem to correct for the deficient alveolar ridge. To overcome this challenge, a novel concept was recently published called "Barbell Technique." This technique has been used more commonly for horizontal bone augmentation. To our knowledge, this is the first report on using the Barbell Technique for vertical bone augmentation. Case Report. This report describes and demonstrates the clinical feasibility of the use of this concept in the reconstruction of a tridimensional alveolar ridge defect in the anterior maxilla. Due to the severity of the defect, both hard and soft tissue deficiencies required augmentation. The first surgery involved a soft tissue grafting procedure while in the second surgical procedure, hard tissue augment was performed using the Barbell device to provide both vertical and horizontal support for the hard tissue graft. The donor material consisted of equal volume of xenograft and autogenous bone used to fill the defect and covered with a collagen barrier membrane. After a healing period of 9 months, the site was reopened. Bone formation clinically verified the correction of alveolar bone contour and volume permitted placement of two titanium implants after the removal of Barbell device. Conclusion: This case report demonstrates successful vertical and horizontal bone augmentation of a critical size defect in the anterior maxilla, correcting both hard and soft tissue contours, and providing the tissues needed to support dental implants in the anterior maxilla.

Barbell Technique: A Novel Approach for Bidirectional Bone Augmentation: Clinical and Tomographic Study.

Horizontal bone augmentation is a common surgical procedure used in implant therapy to achieve adequate bone volume to permit dental implant placement. However, most current techniques are focused on unidirectional bone reconstruction (grafting only on the buccal side). This study was carried out to validate a new device that will permit bidirectional bone augmentation. Ten patients of both sexes (7 women and 3 men), with ages ranging from 29 to 62 years, who needed a bidirectional horizontal bone augmentation in maxilla were separated in accordance with the horizontal alveolar change (HAC) classification published by Pelegrine et al (2018). The patients classified as HAC 3 (ie, containing remaining cancellous bone at the recipient bed) received the Barbell device with xenogeneic biomaterial and a collagen membrane, whereas HAC 4 patients (ie, with no remaining cancellous bone at the recipient bed) received the Barbell device with a mixture of autogenous bone chips and xenogeneic biomaterial covered by a collagen membrane. For each patient, two computerized tomography scans were performed (T0 at baseline and T1 at 6 months postoperative examinations). Mean bone thickness (T0) in the studied sites were 3.25 ± 0.35 in HAC 3 and 1.98 ± 0.5 in HAC 4 patients. The mean bone thickness achieved after 6 months was 7.70 ± 0.89 mm and 8.62 ± 0.89 in HAC 3 and 4, respectively. All grafted sites were able to receive dental implants in adequate prosthetic positions. Based on these results, the use of this novel device permits bidirectional horizontal bone augmentation.

Horizontal Bone Augmentation With Autogenous and Collagenated Xenogeneic Bone Blocks: A Split-Mouth Prospective Clinical, Tomographic, and Histological Pilot Study.

The aim of this study was to compare the clinical, tomographic, and histological performance of collagenated xenogeneic bone blocks (CXBB) in horizontal bone augmentations for implant placement. Five patients with an absence of the 4 upper incisors and an HAC 3 horizontal bone defect, with a remaining of 3 to 5 mm, underwent a bone-grafting procedure with CXBB (test group [TG], n = 5) and autogenous graft (control group [CG], n = 5), with one type of graft used on the right side and other type on the left side. Changes in bone thickness and density (tomographic evaluation), levels of complications (clinically), and distribution pattern between mineralized and nonmineralized tissue (histomorphometrically) were analyzed. Tomographic analysis showed a horizontal bone increase of 4.25 ± 0.78 mm in the TG and 3.08 ± 0.8 mm in the CG between baseline and 8 months postoperatively (P < .05). The horizontal loss between the day of installation of the blocks and 8 months postoperatively was 1.02 ± 0.39 mm for the TG and 1.10 ± 0.71 mm for the CG (P > .05). With regard to bone density, the TG blocks right after installation had 440.2 ± 89.15 HU, and after 8 months, the region reached 730.7 ± 130.98 HU, representing an increase of 29.05%. For the CG blocks, bone density increased from 1052.2 ± 398.35 HU to 1222.5 ± 453.28 HU, representing an increase of 17.03%. The increase in bone density was significantly higher in the TG (P < .05). Clinically, no cases of exposure of the bone blocks and no failure of incorporation were observed. Histomorphometrically, the percentage of mineralized tissue was lower in the TG than in the CG (48.10% ± 2.88% and 53.53% ± 1.05%, respectively), and the opposite was verified for the levels of nonmineralized tissue (52.79% ± 2.88% and 46.47% ± 1.05%, respectively; P < .05). The use of CXBB achieved higher levels of horizontal gain, with lower bone density and lower levels of mineralized tissue when compared with the use of autogenous blocks.

Influence of Titanium Surface Treatments on Viability of Periodontal Fibroblasts Grown in an Osteogenic Culture Medium.

Background: The integrity of the protective seal provided by the gingiva in direct contact with the implant surface is one of the main factors involved in the prevention of peri-implantitis. Aim: The aim of this study was to assess the viability of periodontal fibroblasts grown in an osteogenic culture medium in contact with titanium surfaces treated either with acid etching alone or with acid etching + anodizing. Materials and Methods: Periodontal fibroblasts grown in an osteogenic culture medium were distributed in a control group, with cells grown in culture bottles, and two experimental groups, with cells grown in contact with titanium disks measuring 6 mm in diameter. The surface of the disks was subjected to acid etching alone (AEG, n = 25) or to acid etching + anodizing (ANG, n = 25), and then evaluated using scanning electron microscopy (SEM). Cell viability was assessed by the [3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium] bromide test on days 1, 2, 3, 7, and 14 of the cell culture. The Mann-Whitney test was used for the statistical analysis (P < 0.05). Results: The SEM assessment revealed that the surface of AEG specimens had micrometric characteristics, whereas the surface of ANG specimens had nanometric characteristics. No significant difference was observed among the groups regarding cell viability at any of the evaluation time points. Conclusion: The titanium surface treatments tested did not affect the viability of periodontal fibroblasts in an osteogenic culture medium.

Prevalence of horizontal alveolar changes in edentulous patients: a retrospective tomographic study.

Horizontal bone loss after tooth extraction is a common finding that demands bone reconstruction in various cases. The aim of this study was to assess the horizontal alveolar status in partially and completely edentulous patients using cone-beam computed tomography (CBCT). In total, 1516 CBCT scans of 1404 adult patients were analyzed. Assessment of the images was performed in accordance with the previously published horizontal alveolar change (HAC) classification, which categorizes horizontal bone defects into four classes: HAC 1, HAC 2, HAC 3 and HAC 4 (from the least severe to the most severe condition). Analysis of 1048 scans from partially edentulous patients presented a distribution of 63.55%, 22.14%, 13.36% and 0.95% in HAC 1, HAC 2, HAC 3 and HAC 4, respectively. Analysis of 468 scans from completely edentulous patient images presented a distribution of 19.87%, 28.63%, 41.67% and 9.83% in HAC 1, HAC 2, HAC 3 and HAC 4, respectively. Based on these results, as in HAC 4, no cancellous bone was found between the cortical buccal and lingual/palatal bone plates, it seems reasonable to state that the absence of cancellous bone is higher in completely edentulous patients than in partially edentulous patients. Therefore, the absence of cancellous bone seems to be higher in completely edentulous than in partially edentulous patients.

Reverse torque evaluation in indexed and nonindexed abutments of Morse Taper implants in a mechanical fatigue test.

BACKGROUND: This experimental study assessed reverse torque of indexed and nonindexed (NI) abutments in Morse Taper (MT) implants in a mechanical fatigue test. MATERIALS AND METHODS: In this experimental study It was used 37 implants MT and over them installed Pilar Flex abutments (4.8 mm × 6 mm × 1.5 mm). The groups were as follows: Group A used 19 MT implants with a NI Pilar Flex abutment loaded with 32 N/cm and Group B used 18 MT implants with an indexed (IN) Pilar Flex abutment loaded with 20 N/cm. The abutments were tested according to ISO standard 14801/2007. The specimens were installed at 30° from the axial axis and underwent a 133 N load, 4 Hz frequency, and 1,000,000 cycles. Once the test was completed, the reverse torque was provided by an electronic torque meter. Data were submitted to statistical analysis using the t-test for independent samples and paired t-test. The significance level was considered P < 0.05. RESULTS: Results obtained showed that the indexed Pilar Flex abutment had a percentage of torque loss from the initial torque of 49% and the NI Pilar Flex abutment lost 14%. Paired Student's t-tests revealed that for both NI (P < 0.001) and indexed (P < 0.001) abutments, the counter torque values were significantly lower than those applied at the initial torque. CONCLUSION: According on the methodology used, the NI Pilar Flex abutment was more effective regarding the reverse torque in single-unit implant prostheses versus the indexed Pilar Flex abutment. A greater loosening in the indexed Pilar Flex abutment retaining screw was noted in the reverse torque test, and the Pilar Flex abutment failed to show good outcomes related to the cold welding effect.

Horizontal Bone Reconstruction on sites with different amounts of native bone: a retrospective study.

The lack of guidelines for bone augmentation procedures might compromise decision making in implantology. The objective of this study was to perform a retrospective study to verify the outcomes of horizontal bone reconstruction in implant dentistry with different types of materials and amounts of native bone in the recipient bed to allow for a new guideline for horizontal bone reconstruction. One hundred preoperative CT scans were retrospectively evaluated and categorized in accordance to horizontal bone defects as presence (Group P) or absence (Group A) of cancellous bone in the recipient bed. Different approaches were used to treat the edentulous ridge and the outcomes were defined either as satisfactory or unsatisfactory regarding the possibility of implant placement. The percentage distribution of the patients according to the presence or absence of cancellous bone was 92% for Group P and 8% for Group A. In Group P, 98% of the patients had satisfactory outcomes, and the use of autografts had 100% of satisfactory outcomes in this group. In Group A, 37.5% of the patients had satisfactory outcomes, and the use of autografts also yielded 100% of satisfactory outcomes. The use of allografts and xenografts in Group A had 0% and 33.3% of satisfactory outcomes, respectively. Therefore, it seems reasonable to speculate that the presence of cancellous bone might be predictive and predictable when the decision includes bone substitutes. In cases of absence of cancellous bone in the recipient bed, the use of a vitalized graft seems to be mandatory.

Horizontal Bone Reconstruction on sites with different amounts of native bone: a retrospective study

Abstract: The lack of guidelines for bone augmentation procedures might compromise decision making in implantology. The objective of this study was to perform a retrospective study to verify the outcomes of horizontal bone reconstruction in implant dentistry with different types of materials and amounts of native bone in the recipient bed to allow for a new guideline for horizontal bone reconstruction. One hundred preoperative CT scans were retrospectively evaluated and categorized in accordance to horizontal bone defects as presence (Group P) or absence (Group A) of cancellous bone in the recipient bed. Different approaches were used to treat the edentulous ridge and the outcomes were defined either as satisfactory or unsatisfactory regarding the possibility of implant placement. The percentage distribution of the patients according to the presence or absence of cancellous bone was 92% for Group P and 8% for Group A. In Group P, 98% of the patients had satisfactory outcomes, and the use of autografts had 100% of satisfactory outcomes in this group. In Group A, 37.5% of the patients had satisfactory outcomes, and the use of autografts also yielded 100% of satisfactory outcomes. The use of allografts and xenografts in Group A had 0% and 33.3% of satisfactory outcomes, respectively. Therefore, it seems reasonable to speculate that the presence of cancellous bone might be predictive and predictable when the decision includes bone substitutes. In cases of absence of cancellous bone in the recipient bed, the use of a vitalized graft seems to be mandatory.

Long-term Retrospective Study of Implants Placed after Sinus Floor Augmentation with Fresh-frozen homologous block.

AIM: The aim of this study was to analyze and follow-up implants placed in the posterior maxillary regions previously grafted with homologous bone. MATERIALS AND METHODS: Forty-one grafts with homologous bone blocks were performed in maxillary sinuses, and 121 implants were placed in premolar and molar regions approximately 6 months after the grafts. Patients were followed up for periods varying from 12 to 124 months after rehabilitation. RESULTS: The results showed two implant failures, for a 98.3% success rate during the follow-up period. DISCUSSION: The implants placed had an average torque of 40 N-cm, regardless of the, design, diameter, and length of the implants used. CONCLUSION: After following up on the implants placed in this study, we concluded that those placed in regions of the maxillary sinuses previously grafted with homologous bone blocks had high long-term success rates and met the functional masticatory requirements.

Implantes cerâmicos em casos estéticos: uma nova possibilidade clínica / Dental ceramic implants in aesthetic cases: a new clinical possibility

A substituição de um elemento dental por um implante em pacientes que apresentam tecido gengival delgado gera uma preocupação devido à translucidez gengival, onde a coloração acinzentada do titânio pode levar ao fracasso estético do tratamento. Desta maneira, os implantes de zircônia se diferenciam principalmente por sua coloração clara, a qual se aproxima das características de cor da raiz, e por sua biocompatibilidade, além de possibilitarem a escolha do paciente por um tratamento totalmente livre de metal. Portanto, este relato de caso clínico demonstrou uma inovação técnica por meio da utilização de um implante confeccionado em zircônia para solução de um caso clínico de alta complexibilidade estética em uma paciente jovem, com fenótipo gengival delgado e alto grau de exigência estética. O caso foi finalizado com prótese cimentada e facetas metal free confeccionadas por meio de cerâmica injetada. Após a finalização do caso, concluiu-se que, apesar da desvantagem relacionada à sensibilidade técnica, o implante confeccionado em zircônia possibilitou a solução estética deste caso clínico de fenótipo gengival delgado, sem a necessidade de utilização de enxertos gengivais.

The replacement of a dental element in patients with thin gingival tissue generates a concern due to gingival translucency, where the titanium gray coloration can lead to failure of the treatment. Thus, the zirconia implants are distinguished primarily by their coloration and their biocompatibility, in addition to enabling the selection of a totally metal-free treatment. Therefore, this clinical report, showed an innovative technique using a zirconia implant in a clinical situation with high complex esthetic needs for in a young patient with thin gingival phenotype and high level of aesthetic requirement. The clinical case was concluded with cemented prosthesis and metal-free veneers made by pressed ceramics. After the end of the case, it was concluded that, despite the disadvantage related to the technical sensitivity, the zirconia implant provided an aesthetic solution of this clinical case of thin gingival phenotype, without the need of gingival grafts.

Levantamento de assoalho de seio maxilar û técnicas e materiais para enxertia / Sinus lift û grafting techniques and materials

Repor dentes perdidos através de implantes dentários é cotidiano nas clínicas odontológicas. O posicionamento desses implantes em posição ideal nem sempre é possível, devido às perdas ósseas e às limitações anatômicas que o paciente pode apresentar. Na maxila superior posterior a presença do seio maxilar pode ser um fator complicador para fixação dos implantes, além de que com a pneumatização do mesmo, pode evoluir a um osso muito delgado com uma fina camada cortical. Reabilitar esse tipo de paciente através de implantes pode ser impossível sem a utilização de materiais e técnicas capazes de repor parcial ou total a deficiência óssea, e suportar, em função, os implantes dentários. Atualmente, existem diversos materiais que podem ser utilizados isolados ou em conjunto com outros para levantamento do assoalho do seio maxilar, podendo deixar o cirurgião dentista em dúvida de qual material escolher para cada caso. Esta revisão tem como objetivo transcorrer sobre os materiais de enxertia disponíveis no mercado, baseado em evidências científicas, a fim de esclarecer para o cirurgião quais os substitutos ósseos disponíveis para utilização desse tipo de enxertia...

The treatment with dental implants after teeth loss has become a common practice in dentistry. However, the appropriate implant positioning can be compromised by bone resorption and anatomical limitations presented by mandible/maxilla. The presence of maxillary sinus on posterior region of an edentulous maxilla can hinder maxillary implants, mainly when sinus pneumatization occurs, leading to an insufficient volume of healthy bone for implantÆs placement. Oral rehabilitation with dental implants in such cases may not be executed without previous reconstructive surgical techniques associated to materials that will be able to create adequate bone volume for implant sites. Several materials are available and can be used alone or combined for maxillary sinus floor elevation. Thus their indications should be clarified aiming to guide dental surgeons. This literature review aims to discourse about marketed grafting materials, based on scientific evidence, clarifying which materials are the available for bone replacement on sinus lift...

Maxillary Sinus Augmentation Combining Bio-Oss with the Bone Marrow Aspirate Concentrate: A Histomorphometric Study in Humans.

Purpose. To investigate the regenerative results obtained with the association of bone marrow aspirate concentrate using the Bone Marrow Aspirate Concentrate (BMAC) method to a xenogeneic bone graft (Bio-Oss) in sinus floor elevation. Materials and Methods. Using a randomized controlled study design in eight consecutive patients (age of 55.4 ± 9.2 years), 16 sinus floor lift procedures were performed with Bio-Oss alone (control group, CG, n = 8) or combined with bone marrow aspirate concentrate obtained via the BMAC method (test group, TG, n = 8). Six months after the grafting procedures, bone biopsies were harvested during implant placement and were analyzed by histomorphometry. Results. Histomorphometric analysis revealed a significantly higher amount (p < 0.05) of vital mineralized tissue in TG when compared to the CG (55.15 ± 20.91% and 27.30 ± 5.55%, resp.). For nonvital mineralized tissue, TG presented a statistically higher level of Bio-Oss resorption (p < 0.05) when compared with the CG (6.32 ± 12.03% and 22.79 ± 9.60%, resp.). Both groups (TG and CG) showed no significantly different levels (p > 0.05) of nonmineralized tissue (38.53 ± 13.08% and 49.90 ± 7.64%, resp.). Conclusion. The use of bone marrow concentrate obtained by BMAC method increased bone formation in sinus lift procedures.

The effect of piezosurgery with cvd tip in osteotomy in rat parietal bone: histologic and histomorphometric analysis / O efeito da piezocirurgia com ponta cvd em osteotomia no osso parietal de ratos: estudo histológico e histomorfométrico

O objetivo deste trabalho foi avaliar histológica e histomorfometricamente o efeito da piezocirurgia com ponta CVD em osteotomia realizada no osso parietal de ratos, comparativamente com a resposta do tecido ósseo frente ao protocolo padrão de osteotomia com brocas de tungstênio em baixa rotação. Material e Métodos: Defeitos foram feitos nos ossos parietais de 20 ratos Wistar machos, usando a ponta CVD e broca. Após 3, 7, 14 e 28 dias cinco animais foram sacrificados em cada período e o osso contendo os defeitos submetidos às análises histológica e histomorfométrica. Os resultados obtidos da histomorfometria foram submetidos à análise estatística RM ANOVA com nível de significância de α = 0,05. Os resultados obtidos foram submetidos ainda ao teste de comparação múltipla de Tukey. Resultados: A piezocirurgia promoveu corte preciso e mais lento com menos perda óssea, menor sangramento durante a cirurgia, favorecendo condições para uma reparação mais rápida em comparação com o método tradicional de osteotomia. Os resultados mostraram que nos períodos analisados diferença estatisticamente significativa entre os dois tipos de tratamento (p <0,05). Poucas células inflamatórias, formação óssea rápida, ferida cirúrgica limpa no grupo experimental em todos os períodos. Conclusão: A utilização da piezocirurgia com ponta CVD provou-se válida para a osteotomia, com cortes mais precisos, menos danos aos tecidos, resposta inflamatória menos pronunciada e formação óssea mais rápida nos primeiros períodos quando comparada com a broca de tungstênio em baixa velocidade...

The aim of this study was to compare the response of bone tissue in osteotomy under piezosurgery using a CVD tip in rat parietal bone in contrast with the standard protocol using lowspeed tungsten burs. Material and Methods: A bone defect model was created in parietal bone of 20 male Wistar rats using CVD tip and drill. Five animals were sacrificed after 3, 7, 14 and 28 days and bone containing the defects was submitted to the histologic and histomorphometric analysis. The results of histomorphometry were statistically analyzed using RM ANOVA with a significance level of α = 0.05. The results were still subjected to Tukey’s multiple comparison test. Results: The results showed statistically significant difference (p < 0.05) between the two types of treatment in the analyzed periods. Piezosurgery promoted slower and more precise cut with less bone loss and less bleeding during surgery, promoting conditions for a faster repair compared to the traditional method of osteotomy, fewer inflammatory cells, faster bone formation and cleaner surgical wound in the experimental group in all periods. Conclusion: The use of CVD tip in piezosurgery was proven to be valid for osteotomy, with more precise cuts, less tissue damage, less fewer pronounced inflammatory response and faster bone formation in the early healing periods when compared with low-speed tungsten burs...

Instalação de implante com carga imediata através de um sistema de cirurgia guiada de alta precisão (DIOnavi) / Single implant and immediate loading with a high precision guided surgical system (DIOnavi) – a case report

Os avanços na Implantodontia em busca de resultados previsíveis que possam alinhar estética e função têm levado ao desenvolvimento de sistemas virtuais de planejamento e confecção de guias computadorizados. As cirurgias sem retalho promovem maior conforto aos pacientes, além de apresentarem melhores resultados na manutenção da perda óssea. Entretanto, alguns sistemas ainda apresentam limitações, o que pode levar a diferenças entre o planejamento e o resultado final. Este trabalho teve como objetivo apresentar um caso clínico de instalação de implante com ativação imediata, através do sistema de tecnologia digital de alta precisão DIOnavi (Busan, Coreia). Através de imagens obtidas em tomografias computadorizadas e escaneamento intraoral, o planejamento foi realizado através de um software e um guia cirúrgico, obtido a partir de impressão 3D. Após a instalação do implante, foi instalado um abutment personalizado em titânio e uma coroa provisória cimentada, ambos previamente preparados. O sistema se mostrou eficiente quanto à precisão dos instrumentos e componentes, podendo ser aplicado em diversas situações clínicas, em vista das características.

Advances on implant dentistry aiming predictable results on esthetics and function has led to the development of virtual planning systems and fabrication of computerized surgical guides. Flapless procedures provide more comfort and better results regarding bone loss preservation. However, some systems still have limitations, which can result on differences when the initial and final outcomes are compared. This paper presents a clinical case of immediate implant placement and function using the high-precision digital technology system (DIOnavi, Busan Korea). By means of CBCT and intra-oral scanning, a computer program was used to idealize the surgical guide, with the digital information sent to a 3D-printing machine. After implant placement, the pre-fabricated customized titanium abutment and the cement-retained provisional crown were delivered. This system demonstrated effi ciency related to precision of surgical and prosthetic components and can be recommended for several clinical situations.

Histomorphometric, radiographic and biomechanical analyses of platelet rich plasma associated with autogenous bone graft / Efeito do plasma rico em plaquetas associado ao enxerto autógeno na tíbia de coelhos: estudo histomorfométrico,radiográfico e biomecânico

Objective: The aim of this study was to evaluate the effectiveness of platelet rich plasma with and without autogenous bone graft in the bone repair of surgical defects in rabbit tibias. Material and Methods: In this research, 25 adult male rabbits were used. Two defects have been performed in each tibia, divided into four groups: control (C = defect naturally left to heal by clot formation), autogenous (A = bone defect + autogenous graft), PRP (PRP = bone defect + PRP) and autogenous + PRP (PRPA = bone defect + autogenous graft + PRP). All the defects were covered with a dPTFE membrane. Five other animals were sacrificed at 15, 30, and 60-day postoperatively. The pieces containing the defects were processed for histological and histomorphometric analysis. Other five animals were sacrificed after 30 and 60 days and submitted to biomechanical analysis, and all the specimens were sent to the radiographic evaluation of optical density. Results: The biomechanical, radiographic, and histomorphometric results showed larger resistance, optical density, and improving bone formation in the groups A and PRPA when compared with the groups C and PRP. Conclusion: This study showed there was not an improvement in the radiographic, mechanical, and bone formation parameters when PRP was used individually or associated to the autogenous bone graft...

Objetivo: O propósito deste trabalho foi avaliar o efeito do plasma rico em plaquetas associados ou não ao enxerto ósseo autógeno no processo de reparação óssea em defeitos cirúrgicos confeccionados na tíbia de coelhos. Material e Métodos: Nesta pesquisa foram utilizados 25 coelhos adultos, nos quais foram realizados 2 defeitos em cada tíbia, divididos nos seguintes grupos de acordo com o tratamento: controle (C - defeito preenchido somente por coágulo sangüíneo), autógeno (A - defeito + enxerto), PRP (PRP = defeito + PRP) e autógeno + PRP (PRPA - defeito + enxerto + PRP). Todos os defeitos foram recobertos com uma barreira de PTFE e decorridos 15, 30 e 60 dias, 5 animais foram sacrificados por período, sendo as peças contendo os defeitos processadas para análises histológica e histomorfométrica. Outros 5 animais foram sacrificados aos 30 e 60 dias e submetidos à análise das propriedades biomecânicas e todos os espécimes foram submetidos ao exame radiográfico para análise da densidade óptica. Resutados: Os resultados biomecânicos, radiográficos e histomorfométricos mostraram maior resistência, densidade óptica e maior formação óssea nos grupos A e PRPA quando comparados com os grupos C e PRP. Conclusão: Os resultados obtidos possibilitaram concluir que não houve uma melhora nos parâmetros radiográficos, mecânicos e na neoformação óssea quando o PRP foi usado isoladamente ou associado ao enxerto ósseo autógeno...

Fresh-frozen human bone allograft in vertical ridge augmentation: clinical and tomographic evaluation of bone formation and resorption.

The aim of the current study is to evaluate fresh-frozen human bone allografts (FHBAs) used in vertical ridge augmentation clinically and by computed tomography, and to analyze the resulting bone formation and graft resorption. Sixteen FHBAs were grafted in the maxillae and mandibles of 9 patients. The FHBAs, which were provided by the Musculoskeletal Tissue Bank of Marilia Hospital (Unioss), were frozen at -80°C. After 7 months, dental implants were placed and bone parameters were evaluated. Vertical bone formation was measured by computerized tomography before (T0) and at 7 months (T1) after the surgical procedure. Bone graft resorption was measured clinically from a landmark screw head using a periodontal probe. The results were analyzed by Student's t-test. Significant differences existed in the bone formation values at T0 and T1, with an average change of 4.03 ± 1.69 mm. Bone graft resorption values were 1.0 ± 0.82 mm (20%). Implants were placed with varying insertion torque values (35-45 Ncm), and achieved primary stability. This study demonstrates that FHBAs promote satisfactory vertical bone formation with a low resorption rates, good density, and primary implant stability.

Strength of a feldspar ceramic according to the thickness and polymerization mode of the resin cement coating.

The aim of this study was to evaluate, in vitro, the biaxial flexural strength (ISO 6872) of a feldspathic ceramic (VM7, Vita Zahnfabrik) coated with a resin cement with different thicknesses and polymerization mode. Control groups consisted in VM7 with and without acid etching with 10% hydrofluoric acid for 1 min. Experimental groups comprised VM7 etched, silanated and coated with Variolink II (Ivoclar Vivadent) cement, that was polymerized through the porcelain in light-cure and dual-cure modes, with thickness ≤150 µm or >150 µm. The specimens (n=15) were subjected to the biaxial flexural strength essay and analyzed fractographically. Parametric (Dunnet, Anova 2-way, Tukey) and non-parametric tests (Weibull) were used to evaluate results. Ceramic disks coated with resin cements of either activation modes and thicknesses exhibited higher flexural strength while the Weibull moduli did not present significant differences for a confidence interval of 95%.

Biocompatibility of a chlorhexidine local delivery system in a subcutaneous mouse model.

OBJECTIVE: This study aimed evaluating histologically and histomorphometrically the response of the conjunctive tissue face to the implant of chlorhexidine chips in the subcutaneous tissues of rats. STUDY DESIGN: In this research 35 male rats Wistar were used to analyze the biocompatibility and the degradation process of chlorhexidine chip. In each animal, it was made 2 incisions for subcutaneous implantation of chlorhexidine chip (test group) and a polytetrafluorethylene membrane (control group). The morphological changes in subcutaneous implantations were assessed after 1, 3, 5, 7, 10, 14, 21 days. The data were submitted to Friedman nonparametric test to analyze the comparisons among observation periods and to allow the comparison among groups. RESULTS: Differences were found in the analysis of the inflammatory response when comparing the tested materials (p values ≤ 0.05). In test group was observed hemorrhage, edema and intense inflammatory infiltrate predominantly neutrophilic around material. From 3-day and subsequent periods was verified granulation tissue externally at this infiltrate. From 10-day on was observed crescent area of degradation of chlorhexidine chip, associated with neutrophilic and macrophagic infiltrate, that maintained until 21-day. In the control group, moderate inflammatory infiltrate was observed initially, predominantly polymorphonuclear, edema and granulation tissue 3-day period. The inflammatory infiltrate was gradually replaced for granulation tissue, culminating in a fibrous capsule. Giant multinucleate cells situated at contact interface with the coating was examined since 3-day and persisted until 21-day. CONCLUSION: The chlorhexidine chip induces an intense acute inflammatory response at subcutaneous tissue of rats. Therefore, at conditions of this study was not biocompatible.

Reparação óssea em enxerto alógeno fresco congelado na calvária de coelhos: análises histológica e histomorfométrica / Repair of fresh frozen bone allograft in the calvaria of rabbits: histologic and histomorphometry analyses

A utilização de enxerto ósseo autógeno previamente à instalação de implantes osseointegráveis tem apresentado bons resultados, entretanto, a necessidade de uma segunda área cirúrgica como fonte doadora e o grau de morbidade da técnica têm direcionado a busca por alternativas seguras para a reconstrução óssea. O propósito desta pesquisa foi avaliar o efeito do enxerto de osso alógeno fresco congelado, oriundo de Banco de Tecido, em comparação ao autógeno no processo de reparação de enxertos na calvária de coelhos. Foram utilizados 15 coelhos adultos, nos quais foram realizados 2 enxertos em blocos nos ossos parietais, divididos aleatoriamente nos seguintes grupos de acordo com o tratamento: autógeno (A – enxerto com osso autógeno) e alógeno (B – enxerto com osso alógeno processado em Banco). Decorridos 15, 30 e 60 dias, 5 animais foram sacrificados por período, sendo as peças contendo os enxertos processadas para análises histológica e histomorfométrica. Os resultados foram submetidos ao teste RM ANOVA e de comparação múltipla de Tukey, demonstrando diferenças estatisticamente significantes entre os grupos e entre os tempos estudados. Concluímos que o enxerto alógeno promove formação óssea, porém em menor quantidade e de forma mais lenta em comparação ao enxerto autógeno.

The use of autogenous bone graft prior to installation of dental implants has shown good results, however, the need for a second surgical site and donor source and degree of morbidity of the technique have led the search for safe alternatives to bone reconstruction. The purpose of this study was to evaluate the effect of allogeneic bone graft, fresh frozen from Bank of tissue, as compared to autograft in the repair of calvarial grafts in rabbits. A total of 15 adult rabbits, in which grafts were performed in two blocks in the parietal bone were divided randomly into four groups according to treatment: autogenous (A - with autogenous bone graft) and allogeneic (B - allogeneic bone graft processed in Bank Bone). After 15, 30 and 60 days, five animals were sacrificed by period, and the pieces containing the grafts were processed for histology and histomorphometry. The results were submitted to the RM ANOVA and Tukey's multiple comparison, statistically significant differences between groups and between time points. We conclude that allograft promotes bone formation, but fewer and more slowly compared to autografts.