Evaluation of tissue in repair with natural latex and / or hyaluronic acid in surgical bone defects.

This study evaluated the bone repair in surgical defects of rats treated with hyaluronic acid (HA) associated or not with Hevea brasiliensis fraction protein (F-1). Bone defect were created in 15 albino Wistar rats divided into 3 groups (n=5): Control group (1) - blood clot; HA group (2) - 0.5% hyaluronic acid; HAF1 group (3) - 0.1% F-1 protein fraction dissolved in 0.5% hyaluronic acid. After 4 weeks, the animals were euthanized and the bone repair was evaluated through histomorphometric analysis, zymography and immunohistochemistry. The neoformed bone area did not show a significant difference (p = 0.757), but there was a tendency for bone trabeculation to increase in the groups HA and HAF1. For immunohistochemically analysis, there was a difference in vascular endothelial growth factor (VEGF) labeling (p = 0.023), being higher in the groups HA and HAF1 than the control group. No significant difference in bone sialoprotein (BSP) (p = 0.681), osteocalcin (p = 0.954), however, significant difference in platelet endothelial cell adhesion molecule-1 (CD-31) (p = 0.040), with HAF1 group being significantly lower than the control. For zymographic analysis, there was no significant difference for metalloproteinase-2 (MMP-2) (p = 0.068), but there was a tendency to increase MMP-2 in the HA group. Despite the influence on angiogenic factors and the apparent tendency for greater trabeculation in the HA and HAF1 groups, there was no significant difference in the area of ​​newly formed bone tissue in the analyzed period.

Evaluation of tissue in repair with natural latex and / or hyaluronic acid in surgical bone defects

Abstract This study evaluated the bone repair in surgical defects of rats treated with hyaluronic acid (HA) associated or not with Hevea brasiliensis fraction protein (F-1). Bone defect were created in 15 albino Wistar rats divided into 3 groups (n=5): Control group (1) - blood clot; HA group (2) - 0.5% hyaluronic acid; HAF1 group (3) - 0.1% F-1 protein fraction dissolved in 0.5% hyaluronic acid. After 4 weeks, the animals were euthanized and the bone repair was evaluated through histomorphometric analysis, zymography and immunohistochemistry. The neoformed bone area did not show a significant difference (p = 0.757), but there was a tendency for bone trabeculation to increase in the groups HA and HAF1. For immunohistochemically analysis, there was a difference in vascular endothelial growth factor (VEGF) labeling (p = 0.023), being higher in the groups HA and HAF1 than the control group. No significant difference in bone sialoprotein (BSP) (p = 0.681), osteocalcin (p = 0.954), however, significant difference in platelet endothelial cell adhesion molecule-1 (CD-31) (p = 0.040), with HAF1 group being significantly lower than the control. For zymographic analysis, there was no significant difference for metalloproteinase-2 (MMP-2) (p = 0.068), but there was a tendency to increase MMP-2 in the HA group. Despite the influence on angiogenic factors and the apparent tendency for greater trabeculation in the HA and HAF1 groups, there was no significant difference in the area of ​​newly formed bone tissue in the analyzed period.

Resumo Este estudo avaliou o reparo ósseo em defeitos cirúrgicos de ratos tratados com ácido hialurônico (AH) associado ou não à fração proteica de Hevea brasiliensis (F-1). Foram criados defeitos ósseos em 15 ratos albinos Wistar divididos em 3 grupos (n = 5): Grupo controle (1) - coágulo sanguíneo; Grupo HA (2) - ácido hialurônico 0,5%; Grupo HAF1 (3) - fração proteica F-1 0,1% dissolvida em ácido hialurônico a 0,5%. Após 4 semanas, os animais foram submetidos à eutanásia e o reparo ósseo avaliado por meio de análise histomorfométrica, zimografia e imunohistoquímica. A área óssea neoformada não apresentou diferença significativa (p = 0,757), mas houve tendência de aumento da trabeculação óssea nos grupos HA e HAF1. Para a análise imunoistoquímica, houve diferença na marcação do fator de crescimento endotelial vascular (VEGF) (p = 0,023), sendo maior nos grupos HA e HAF1 do que no grupo controle. Nenhuma diferença significativa na sialoproteína óssea (BSP) (p = 0,681), osteocalcina (p = 0,954), no entanto, diferenças significativas foram encontradas para a molécula de adesão de células endoteliais plaquetárias-1 (CD-31) (p = 0,040), com o grupo HAF1 sendo significativamente inferior ao controle. Para a análise zimográfica, não houve diferença significativa para metaloproteinase-2 (MMP-2) (p = 0,068), mas houve tendência de aumento da MMP-2 no grupo HA. Apesar da influência sobre os fatores angiogênicos e da aparente tendência de maior trabeculação nos grupos HA e HAF1, não houve diferença significativa na área de tecido ósseo neoformado no período analisado.

Medição da cortical óssea através de radiografia panorâmica para diagnóstico de osteopenia e osteoporose em mulheres / Measurement of the cortical bone by panoramic radiography for the diagnosis of osteopenia and osteoporosis in women

RESUMO: Modelo do estudo: Estudo de prevalência. Objetivo: Avaliar a prevalência de osteopenia e osteoporose diagnosticadas por radiografia panorâmica através de medidas qualitativas do córtex ósseo mandibular. Materiais e métodos: Foram utilizados o índice de Klemetti e o índice de Benson através de paquímetro digital. A análise descritiva dos dados foi realizada no Statistical Package for the Social Sciences (SPSS) V.20.0. Resultados: Das cinquenta radiografias panorâmicas avaliadas de mulheres com média de idade de 43,04 anos, 15 mulheres (30%) foram diagnosticadas com osteopenia pelo índice de Klemetti, não havendo casos de osteoporose na amostra. Em relação ao índice de Benson, os resultados mostraram média de 4,24 mm (DP: 0,54), com valor mínimo de 3,30 e máximo de 6,10 mm. Conclusão: Nossos achados evidenciam a importância da radiografia panorâmica para o diagnóstico precoce de osteopenia e osteoporose. A radiografia panorâmica apresenta baixo custo e facilidade de uso pelos cirurgiões-dentistas, sendo um exame amplamente utilizado em diversas áreas da odontologia. (AU)

ABSTRACT: Study design: Prevalence study. Aim: Evaluating the prevalence of osteopenia and osteoporosis diagnosed by panoramic radiography through qualitative measurements of the mandibular bone cortex. Materials and methods: The Klemetti index and the Benson index were used through a digital caliper. The descriptive analysis of the date was performed in the Statistical Package for the Social Sciences (SPSS) V.20.0. Results: Of the fifty panoramic radiographs evaluated from women with a mean age of 43.04 years, 15 women (30%) were diagnosed with Klemetti's osteopenia, and there were no cases of osteoporosis in the sample. Regarding the Benson index, the results showed an average of 4.24 mm (SD: 0.54), with a minimum value of 3.30 and a maximum of 6.10 mm. Conclusion: Our findings highlight the importance of panoramic radiography for the early diagnosis of osteopenia and osteoporosis. Panoramic radiography presents low cost and ease of use by dental surgeons, being an exam widely used in several areas of dentistry. (AU)

Exodontia-induced muscular hypofunction by itself or associated to chronic stress impairs masseter muscle morphology and its mitochondrial function.

Stress is associated with orofacial pain sensitivity and is qualified as a temporomandibular disorder risk factor. During stressful periods, painful thresholds of masticatory muscles in individuals suffering muscle facial pain are significantly lower than in controls, but the exact physiologic mechanism underlying this relation remains unclear. Our hypothesis is that chronic unpredictable stress and masticatory hypofunction induce morphologic and metabolic masseter muscle changes in rats. For test this hypothesis, adult Wistar rats were submitted to chronic unpredictable stress and/or exodontia of left molars and the left masseter muscle was removed for analysis. The parameters evaluated included ultrastructure, oxidative level, metabolism activity and morphological analysis in this muscle. Our data show by histological analysis, that stress and exodontia promoted a variation on diameters and also angled contours in masseter fibers. The masticatory hypofunction increased oxidative metabolism as well as decreased reactive species of oxygen in masseter muscle. The ultrastructural analysis of muscle fibers showed disruption of the sarcoplasmic reticulum cisterns in certain regions of the fiber in stress group, and the disappearance of the sarcoplasmic reticulum membrane in group with association of stress and exodontia. Our findings clarify mechanisms by which chronic stress and masticatory hypofunction might be involved in the pathophysiology of muscular dysfunctions. Masticatory hypofunction influenced oxidative stress and induced oxidative metabolism on masseter muscle, as well as altered its fiber morphology. Chronic stress presented malefic effect on masseter morphology at micro and ultra structurally. When both stimuli were applied, there were atrophic fibers and a complete mitochondrial derangement.

Metabolic and vascular pattern in medial pterygoid muscle is altered by chronic stress in an animal model of hypodontia.

Psychological stress is an important perpetuating, worsening and risk factor for temporomandibular disorders of muscular or articular origin. Occlusion instability, by the way, is considered a risk factor of this pathology and can be reproduced in some experimental animal models. The exact physiologic mechanism underlying these relations however, remains unclear. Our purpose was to test the hypothesis that chronic stress and unilateral exodontia induce metabolic and vascular changes in the medial pterygoid muscle of rats. Adult Wistar rats were submitted to chronic unpredictable stress and/or unilateral exodontia and their plasma and medial pterygoid muscle were removed for analysis. The parameters evaluated included plasma levels of corticosterone, metabolic activity by succinate dehydrogenase, oxidative capacity by nicotinamide adenine dinucleotide diaphorase, capillary density by laminin and alfa-CD staining and reactive oxidative species production. Chronic unpredictable stress as an isolated factor, increased oxidative metabolism, capillary density and reactive oxygen species production at medial pterygoid muscle. Conversely, exodontia has a main effect in metabolism, promoting glycolytic transformation of muscle fibers. Association of both factors induced a major glycolytic pattern in muscle and vascular changes. Our findings provide insights into the mechanisms, possibly inducing metabolic and vascular alterations on medial pterygoid muscle of rats, by which chronic stress and occlusal instabilities might be involved as risk factors in the pathophysiology of temporomandibular disorders with muscular components.

Early diagnosis of atherosclerosis with panoramic radiographs: a review / O diagnóstico precoce de aterosclerose através de radiografias panorâmicas: uma revisão

Abstract Carotid artery disease has been linked with cerebral vascular accident, also known as stroke, cerebral hemorrhage, or cerebral ischemia. It is caused by narrowing or obstruction of arteries in the neck (the carotid arteries) that are responsible for transporting blood from the aorta to the brain. Panoramic radiographs are used in dentistry to show both dental arches as a supplement to the clinical dental examination. The objective of this study is to highlight the importance of panoramic radiographs for diagnosis of arterial disease, by means of a bibliographic review. The PubMed database was searched using the keywords “atherosclerosis” and “panoramic”, with the filters “last 5 years” and “humans”. Twenty articles were identified, six of which were chosen for this study because they were open access. The review concluded that panoramic radiographs enable early diagnosis of carotid artery calcification, resulting in earlier interventions, and offer an accessible cost.

Resumo Doenças das artérias carótidas estão associadas a casos de acidente vascular cerebral, também chamados de derrame ou isquemia cerebral. Ocorrem devido ao estreitamento ou obstrução das artérias do pescoço, ou artérias carótidas, responsáveis por levar o sangue da aorta para o cérebro. A radiografia panorâmica é um exame de ambos os arcos dentários que ajuda no exame clínico odontológico. Destacar a importância da radiografia panorâmica no diagnóstico de doença arterial é o objetivo deste trabalho, que foi realizado através de pesquisa bibliográfica na PubMed, com as palavras-chave “atherosclerosis” e “panoramic”, e os filtros: últimos 5 anos e humanos. Vinte artigos foram elencados, dos quais seis formaram a base para este estudo, graças ao acesso livre ao seu conteúdo. Conclui-se que a radiografia panorâmica permite o diagnóstico precoce de calcificação da artéria carótida, levando a uma intervenção precoce a um custo acessível.

Chronic stress effects in contralateral medial pterygoid muscle of rats with occlusion alteration.

Temporomandibular disorder (TMD) has a high prevalence in our society, characterized by a severe pain condition of the masticatory muscles and temporomandibular joint. Despite the indication of multiple factor initiators of TMD, there is still controversy about its etiology and its pathophysiology is poorly understood. Using rats as experimental animals we investigated the effect of unpredictable chronic stress with or without unilateral molar extraction on the contralateral medial pterygoid muscle. Our hypothesis is that these two factors induce changes in morphology, oxidative metabolism and oxidative stress of muscle fibers. Young adult male Wistar rats (±200g) were divided into four groups: a group with extraction and unpredictable chronic stress (E+US); with extraction and without stress (E+C); without extraction and with unpredictable chronic stress (NO+US); and a control group without either extraction or stress (NO+C). The animals were subjected to unilateral extraction of the upper left molars, under intraperitoneal anesthesia with 4% Xylazine (10mg/kg) and 10% Ketamine (80mg/kg) on day zero. The rats of groups E+US and NO+US were submitted to different protocols of stress, from the 14th day after the extraction. The protocols were different every day for five consecutive days, which were repeated from the 6th day for five days more. Contralateral medial pterygoid muscles were obtained on the 24th day after the start of the experiment for morphological, metabolic, capillary density, and oxidative stress analysis. The data from capillary density showed a decrease of capillaries in animals subjected to dental extraction, compared with those without extraction and an increase of laminin expression in the group submitted to the unpredictable chronic stress when compared to the unexposed to stress. SDH test revealed a decrease of light fibers in the group submitted to unilateral extraction of molars, compared with this area in the control group. In E+US and NO+US groups, the deeply stained fibers increased compared to NO+C.·The exodontia factor was able to increase the ROS activity in muscle, whereas the stress factor does not significantly alter ROS in this tissue. It was concluded that both unpredictable chronic stress and the extraction induce metabolic and density of capillary changes in the contralateral medial pterygoid muscle to extraction, suggesting that these factors for a longer period of this experiment could induce muscle damage related to TMD.

Early diagnosis of atherosclerosis with panoramic radiographs: a review.

Carotid artery disease has been linked with cerebral vascular accident, also known as stroke, cerebral hemorrhage, or cerebral ischemia. It is caused by narrowing or obstruction of arteries in the neck (the carotid arteries) that are responsible for transporting blood from the aorta to the brain. Panoramic radiographs are used in dentistry to show both dental arches as a supplement to the clinical dental examination. The objective of this study is to highlight the importance of panoramic radiographs for diagnosis of arterial disease, by means of a bibliographic review. The PubMed database was searched using the keywords "atherosclerosis" and "panoramic", with the filters "last 5 years" and "humans". Twenty articles were identified, six of which were chosen for this study because they were open access. The review concluded that panoramic radiographs enable early diagnosis of carotid artery calcification, resulting in earlier interventions, and offer an accessible cost.

Doenças das artérias carótidas estão associadas a casos de acidente vascular cerebral, também chamados de derrame ou isquemia cerebral. Ocorrem devido ao estreitamento ou obstrução das artérias do pescoço, ou artérias carótidas, responsáveis por levar o sangue da aorta para o cérebro. A radiografia panorâmica é um exame de ambos os arcos dentários que ajuda no exame clínico odontológico. Destacar a importância da radiografia panorâmica no diagnóstico de doença arterial é o objetivo deste trabalho, que foi realizado através de pesquisa bibliográfica na PubMed, com as palavras-chave "atherosclerosis" e "panoramic", e os filtros: últimos 5 anos e humanos. Vinte artigos foram elencados, dos quais seis formaram a base para este estudo, graças ao acesso livre ao seu conteúdo. Conclui-se que a radiografia panorâmica permite o diagnóstico precoce de calcificação da artéria carótida, levando a uma intervenção precoce a um custo acessível.

Metabolic Changes in Masseter Muscle of Rats Submitted to Acute Stress Associated with Exodontia.

Clinical evidence has shown that stress may be associated with alterations in masticatory muscle functions. Morphological changes in masticatory muscles induced by occlusal alterations and associated with emotional stress are still lacking in the literature. The objective of this study was to evaluate the influence of acute stress on metabolic activity and oxidative stress of masseter muscles of rats subjected to occlusal modification through morphological and histochemical analyses. In this study, adult Wistar rats were divided into 4 groups: a group with extraction and acute stress (E+A); group with extraction and without stress (E+C); group without extraction and with acute stress (NO+A); and control group without both extraction and stress (NO+C). Masseter muscles were analyzed by Succinate Dehydrogenase (SDH), Nicotinamide Adenine Dinucleotide Diaphorase (NADH) and Reactive Oxygen Species (ROS) techniques. Statistical analyses and two-way ANOVA were applied, followed by Tukey-Kramer tests. In the SDH test, the E+C, E+A and NO+A groups showed a decrease in high desidrogenase activities fibers (P < 0.05), compared to the NO+C group. In the NADH test, there was no difference among the different groups. In the ROS test, in contrast, E+A, E+C and NO+A groups showed a decrease in ROS expression, compared to NO+C groups (P < 0.05). Modified dental occlusion and acute stress--which are important and prevalent problems that affect the general population--are important etiologic factors in metabolic plasticity and ROS levels of masseter muscles.

Muscle characterization of reactive oxygen species in oral diseases.

IMPORTANCE AND OBJECTIVE: Reactive Oxygen Species (ROS) are oxygen-derived molecules that are unstable and highly reactive. They are important signaling mediators of biological processes. In contrast, excessive ROS generation, defective oxidant scavenging or both have been implicated in the pathogenesis of several conditions. This biological paradox of ROS function contributes to the integrity of cells and tissues. So, the aim of this review was examined for published literature related to 'reactive oxygen species and dentistry and muscle'. MATERIALS AND METHODS: A PubMed search was performed by using the following key words: 'reactive oxygen species and dentistry and muscle'. RESULTS: Involvement of ROS in pathologic conditions can be highlighted in oral diseases like periodontitis, orofacial pain, temporomandibular disorders and oral cancer. Also, several studies have correlated the increase in ROS production with the initiation of the muscle fatigue process and the process of muscle injury. However, studies evaluating the relation of ROS and orofacial muscles, which can prove very important to understand the fatigue muscle in this region during oral movements, have not yet been conducted. CONCLUSIONS: It is concluded that the data on skeletal muscles, especially those of mastication, are not commonly published in this data source; therefore, further studies in this field are strongly recommended.

Common positioning errors in panoramic radiography: A review.

Professionals performing radiographic examinations are responsible for maintaining optimal image quality for accurate diagnoses. These professionals must competently execute techniques such as film manipulation and processing to minimize patient exposure to radiation. Improper performance by the professional and/or patient may result in a radiographic image of unsatisfactory quality that can also lead to a misdiagnosis and the development of an inadequate treatment plan. Currently, the most commonly performed extraoral examination is panoramic radiography. The invention of panoramic radiography has resulted in improvements in image quality with decreased exposure to radiation and at a low cost. However, this technique requires careful, accurate positioning of the patient's teeth and surrounding maxillofacial bone structure within the focal trough. Therefore, we reviewed the literature for the most common types of positioning errors in panoramic radiography to suggest the correct techniques. We would also discuss how to determine if the most common positioning errors occurred in panoramic radiography, such as in the positioning of the patient's head, tongue, chin, or body.

Zymographic and ultrastructural evaluations after low-level laser irradiation on masseter muscle of HRS/J strain mice.

Low-level laser therapy (LLLT) has been widely used in the treatment of the stomatognathic system dysfunction; however, its biological effect remains poorly understood. This study evaluated the effect of LLLT (GaAlAs, 780 nm, 20 J/cm(2), 40 mW) on masseter muscle of HRS/J mice after different numbers of laser irradiations (three, six, and ten) for 20 s in alternate days. Three experimental groups were defined according to the number of laser irradiations and three control groups (n=5) were used. On the third day after the last irradiation, all animals were killed and the masseter muscle was removed and processed for the following analysis: (a) transmission electron microscopy, (b) zymography, (c) immunohistochemistry for vascular endothelial growth factor (VEGF) and VEGFR-2. The results showed: (a) with six laser applications, a dilation of T tubules, and sarcoplasmic reticulum cistern, increased pinocytosed vesicles in the endothelium; with ten laser applications, few pinocytic vesicles in the endothelium and condensed mitochondria. (b) Under the conditions of this study, the synthesis of other matrix metalloproteinases was not observed, only the MMP-2 and -9. (c) After ten laser irradiations, immunostaining was observed only for VEGFR-2. We conclude that after six laser applications, ultrastructural changes may facilitate the Ca(+2) transfer to cytosol and increase the fluid transport from one surface to another. The ultrastructural changes and no immunostaining for VEGF with ten applications may decrease the metabolic activity as well as damage the angiogenic process, suggesting that an effective number of laser applications may be less than ten, associating to this therapy a better cost-benefit.

The use of bisphosphonates in dental clinic: a review of the last five years / O uso de bisfosfonatos na clinica dentária: uma revisão dos últimos cinco anos

The bisphosphonates are synthetic drugs used for treatment of neoplasms and bone, Paget’s disease and more reason for excitement in cases of postmenopausal osteoporosis. These drugs present some known side effects, however, a new complication with oral manifestation was recently identified, called Osteonecrosis. When this necrosis of the bone bases is associated to the use of Bisphosphonates, it is named Osteonecrosis by Bisphosphonates. The type of bisphosphonate, route of administration, and duration of treatment with these drugs seem to have direct relation with the incidence of osteonecrosis associated with bisphosphonates. The aim of this work was to present a review of the last five years about the use of bisphosphonates, the available bisphosphonate groups in the Brazilian market emphasizing those used in the treatment of Osteonecrosis, and exploring possible diagnostic aspects of the disease from image Diagnostics. It is concluded the impact of current world life stimulates new research areas focusing on important illnesses, their manifestations, and on searching for better treatment protocols and faster diagnosis protocols, aiming reduce possible treatment unwanted side effects

Os bisfosfonatos são drogas sintéticas usadas no tratamento de neoplasias de osso, doença de Paget e nos casos de osteoporose pós-menopáusica. Estas drogas apresentam alguns efeitos colaterais conhecidos, no entanto, uma nova complicação com manifestação oral foi recentemente identificada, chamada osteonecrose. Quando a necrose das bases ósseas está associada à utilização de bisfosfonatos, é nomeada osteonecrose por bisfosfonatos. O tipo de Bisfosfonato, a via de administração e duração do tratamento com estes medicamentos parecem ter uma relação direta com a incidência da osteonecrose. O objetivo deste trabalho foi apresentar uma revisão dos últimos cinco anos sobre o uso de Bisfosfonatos e os grupos de Bifosfonatos disponíveis no mercado brasileiro, enfatizando aqueles usados no tratamento da osteonecrose, além de explorar possíveis aspectos de diagnóstico da doença por meio de imagem. Conclui-se que novas áreas de pesquisa, com foco em doenças importantes e as suas manifestações, estão buscando melhores protocolos no tratamento e diagnóstico rápido, visando reduzir possíveis efeitos colaterais indesejados

Influence of low-level laser associated with osteogenic proteins recombinant human BMP-2 and Hevea brasiliensis on bone repair in Wistar rats.

This study analyzed the newly formed bone tissue after application of recombinant human BMP-2 (rhBMP-2) and P-1 (extracted from Hevea brasiliensis) proteins, 2 weeks after the creation of a critical bone defect in male Wistar rats treated or not with a low-intensity laser (GaAlAs 780 nm, 60 mW of power, and energy density dose of 30 J/cm(2)). The animals were divided into two major groups: (1) bone defect plus low-intensity laser treatment and (2) bone defect without laser irradiation. The following subgroups were also analyzed: (a) 5 µg of pure rhBMP-2; (b) 5 µg of pure P-1 fraction; (c) 5 µg of rhBMP-2/monoolein gel; (d) 5 µg of P-1 fraction/monoolein gel; (e) pure monoolein gel. Comparisons of the groups receiving laser treatment with those that did not receive laser irradiation show differences in the areas of new bone tissue. The group treated with 5 µg of rhBMP-2 and laser irradiation was not significantly different (P >0.05) than the nonirradiated group that received the same treatment. The irradiated, rhBMP-2/monoolein gel treatment group showed a lower area of bone formation than the nonirradiated, rhBMP-2/gel monoolein treatment group (P < 0.001). The area of new bone tissue in the other nonirradiated and irradiated groups was not significantly different (P > 0.05). Furthermore, the group that received the 5 µg of rhBMP-2 application showed the greatest bone formation. We conclude that the laser treatment did not interfere with the area of new bone tissue growth and that the greatest stimulus for bone formation involved application of the rhBMP-2 protein.

Bone repair investigation using rhBMP-2 and angiogenic protein extracted from latex.

BACKGROUND: The aim of this work was to study the new bone tissue formation after bone morphogenetic protein type 2 (rhBMP-2) and P-1 application, using 5 and 10 µg of each, combined to a material carrier, in critical bone defects. METHODS: It was used 70 Wistar rats (male, ∼250 g) that were divided in 10 groups with seven animals on each. Groups are the following: critical bone defect only, pure monoolein gel, 5 µg of pure P-1, 5 µg of pure rhBMP-2, 5 µg of P-1/monoolein gel, 5 µg of rhBMP-2/monoolein gel, 10 µg of pure P-1, 10 µg of pure rhBMP-2, 10 µg of P-1/monoolein gel, 10 µg of rhBMP-2/monoolein gel. Animals were sacrificed after 4 weeks of the surgical procedure and the bone samples were submitted to histological, histomorphometrical, and immunohistochemical evaluations. RESULTS: Animals treated with pure P-1 protein, in both situations with 5 µg and 10 µg, had no significant difference (P > 0.05) for new bone formation; other groups treated with 10 µg were statistically significant (P < 0.05) among themselves and when compared with groups in which it was inserted the monoolein gel or critical bone defect only (P < 0.05). In the group involving the 10 µg rhBMP-2/monoolein gel association, it was observed an extensive bone formation, even when compared with the same treatment without the gel carrier. CONCLUSION: Using this experimental animal model, more new bone tissue was found when it was inserted the rhBMP-2, especially when this protein was combined to the vehicle, and this process seems to be dose dependent.