Neurovascular disturbances after implant surgery

With a steadily increasing impact of oral implant placement in daily practice, the number of reported surgical complications has also been growing. Recent studies reveal significant variation in the occurrence and morphology of neurovascular canal structures in the jaw bone. All those structures contain a neurovascular bundle, the diameter of which may be large enough to cause clinically significant damage. Therefore, it has become obvious that presurgical radiographic planning of jaw-bone surgery should pay attention to the neurovascular structures and their likely variations, in addition to examining many other factors, such as jaw-bone morphology and volume, bone trabecular structure and the absence of bone or tooth pathology. A critical review is accomplished to explore the potential risks for neurovascular complications after implant placement, with evidence derived from histologic, anatomic, clinical and radiologic studies. In this respect, cross-sectional imaging can often be advocated, as it is obvious that the inherent three-dimensional nature of jaw-bone anatomy may clearly benefit from a detailed spatial image analysis. Although this could initially be realized by conventional computed tomography, in current practice, dentomaxillofacial cone beam computed tomography might be used, as it offers high-quality images at low radiation dose levels and costs.

Osteonecrosis de los maxilares y bifosfonatos : revisión

La osteonecrosis de los maxilares es la necrosis y exposición del hueso de la mandíbula y el maxilar, asociada al consumo de bifosfonatos. Estos son una familia de drogas que se utiliza en el tratamiento de alteraciones óseas causadas principalmente por tumores malignos (mama y próstata) y osteoporosis. No existe irradiación previa. El hueso macroscópicamente se ve sucio avascular. El objetivo de este artículo es profundizar el conocimiento sobre los bifosfonatos, factores causales de las lesiones.

A redescription of Atopacanthus dentatus Hussakof and Bryant, 1918 (Acanthodii, Ischnacanthidae)

The holotype specimen of the ischnacanthid acanthodian Alopacanthus dentatus comprises most of the posterior half of a dentigerous jaw bone, rather than a fragment from the middle of the jaw as was previously believed. A new diagnosis and revised description for the taxon are based on the holotype from the Rhinestreet Shale (Frasnian) and other specimens front the North Evans and Genundewa limestones (early Frasnian) of the Genesee Formation (late Givetian-early Frasnian); all of: these dentigerous jaw bones were collected near Hamburg, New York state, U.S.A. An emended diagnosis for Atopacanthus clarifies the differences between it and other ischnacanthid genera.

Morfometria dos forames mandibular, mentual e infraorbital de Lobo-guará Chrysocyon brachyurus, Illiger, 1815 aplicada a bloqueios anestésicos

CHAPTER II - The Chrysocyon brachyurus is the biggest South American canid which has a high frequency of dental injuries, both in wild and captivity. Thus, veterinary procedures are necessary to preserve the feeding capacity of hundreds of captive specimens worldwide. The aim of this study was to study the mandibular morphometry of maned wolf with emphasis on the establishment of anatomic references to the anesthetic blockage of the inferior alveolar and mental nerves. Therefore, 15 measurements in 22 hemimandibles of C. brachyurus adults were taken. For extra-oral technique of blockage of the inferior alveolar nerve at the level of the mandibular foramen, it is stated that the needle should be advanced, close to the medial surface of the mandibular ramus, by 11.4 mm perpendiculary from the palpable concavity. Alternatively, the needle can be introduced for 30.4 mm from the angular process at 20-25 degrees angle with the ventral margin. For blocking only the mentual nerve, it is recommended the introduction of needle for 10 mm, close to the lateral aspect of the mandibular body, at the level of the lower first premolar. The mandibular foramen showed similars position, size and symmetry in the maned wolfs specimens examined. The comparison of the data with those available for other carnivores reflects the necessity for determining these anatomical references specifically for each species.

Avanço dos biomateriais e técnicas na correção dos defeitos ósseos maxilares

Introdução: Determinar as causas da perda óssea nos maxilares, compreender os mecanismos biológicos desencadeados após a perda dental e criar recursos técnicos no intúito de prevenir e/ou minimizar as sequélas decorrentes, tem sido ao longo dos anos uma das vertentes de maior pesquisa e desenvolvimento na medicina dental . Objetivo: Assim, o objetivo desta dissertação é realizar uma revisão da literatura sobre os avanços nos biomateriais e técnicas na correção dos defeitos ósseos maxilares, para que seja possível, futuramente, ampliar as suas aplicações em Medicina Dentária, ultrapassando as limitações das técnicas e materiais existentes atualmente. Metodologia: Para isso, foi realizada uma pesquisa de artigos na base de dados PubMed, Bireme, Lilacs, Medline, revistas e periódicos nos idiomas: português, inglês e espanhol; assim como livros consagrados na literatura médico-odontológica,com o recurso a limites e palavras-chave de forma a refinar essa pesquisa. Desenvolvimento: Os avanços nos biomateriais e técnicas na correção dos defeitos ósseos maxilares tem seguido, assim como os implantes dentais, dois principais eixos de pesquisa, primeiro no que diz respeito aos biomateriais empregados pós-exodontia, a prevenir a reabsorção osséa e aqueles utilizados à fim de corrigir defeitos já existentes; a aplicação destes materiais recai sobre fatores que são decisivos na escolha do cirurgião, tais como: disponibilidade, necessidade de procedimento cirúrgico adicional, compatibilidade, morbidade do enxerto, qualidade do osso resultante e tempo de neo-formação. Segundo, as técnicas e recursos desenvolvidos para garantir a eficáz correção do defeito, assim como proporcionar procedimentos menos traumaticos ao organismo e de maior simplicidade e previsibilidade na sua execução e reprodução pelos profissionais. Discussão: Os trabalhos desenvolvidos em volta dos biomateriais atualmente buscam não só o substituto ideal, mas sim a melhoria na interação entre o osso hospedeiro e o biomaterial enxertado perante os recursos já utilizados e consagrados pelas literaturas; assim como a utilização das técnicas já protocoladas de forma associada a estes novos materiais. Conclusão: As pesquisas sobre o aperfeiçoamento do processo de regeneração óssea nos defeitos maxilares avançam na questão de promover a rápida e eficaz interação entre organismo e biomaterial, a fim de trazer soluções para problemas como a anti-genicidade, previsibilidade dimensional, menor tempo entre a enxertia e a reabilitação protética e agrega-se a utilização de recursos técnicos práticos, uma vez que o planejamento da reabilitação inicia-se nas decisões pré-exodontias e pré-implantares.

Jaw and Long Bone Marrows Have a Different Osteoclastogenic Potential

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mandibular cortical bone evaluation on cone beam computed tomography images of patients with bisphosphonate-related osteonecrosis of the jaw

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Bisphosphonate-related Osteonecrosis Of The Jaw: A Review Of The Literature.

Bisphosphonates (BPs) are a class of drugs used to treat osteoporosis and malignant bone metastasis. BPs show high binding capacity to the bone matrix, especially in sites of active bone metabolism. The American Society for Bone and Mineral Research defines BRONJ as an area of exposed bone in the maxillofacial region that has not healed within 8 weeks after identification by a healthcare provider in a patient who is receiving or has been exposed to a bisphosphonate and has not had radiation therapy to the craniofacial region. Bisphosphonate-related osteonecrosis of the jaw (BRONJ) can adversely affect quality of life, as it may produce significant morbidity. The American Association of Oral and Maxillofacial Surgeons (AAOMS) considers as vitally important that information on BRONJ be disseminated to other dental and medical specialties. The purpose of this work is to offer a perspective on how dentists should manage patients on BPs, to show the benefits of accurately diagnosing BRONJ, and to present diagnostic aids and treatments strategies for the condition.

Discovery Of A Rare Pterosaur Bone Bed In A Cretaceous Desert With Insights On Ontogeny And Behavior Of Flying Reptiles.

A pterosaur bone bed with at least 47 individuals (wing spans: 0.65-2.35 m) of a new species is reported from southern Brazil from an interdunal lake deposit of a Cretaceous desert, shedding new light on several biological aspects of those flying reptiles. The material represents a new pterosaur, Caiuajara dobruskii gen. et sp. nov., that is the southermost occurrence of the edentulous clade Tapejaridae (Tapejarinae, Pterodactyloidea) recovered so far. Caiuajara dobruskii differs from all other members of this clade in several cranial features, including the presence of a ventral sagittal bony expansion projected inside the nasoantorbital fenestra, which is formed by the premaxillae; and features of the lower jaw, like a marked rounded depression in the occlusal concavity of the dentary. Ontogenetic variation of Caiuajara dobruskii is mainly reflected in the size and inclination of the premaxillary crest, changing from small and inclined (∼ 115°) in juveniles to large and steep (∼ 90°) in adults. No particular ontogenetic features are observed in postcranial elements. The available information suggests that this species was gregarious, living in colonies, and most likely precocial, being able to fly at a very young age, which might have been a general trend for at least derived pterosaurs.

Epidemiology and risk factors for osteonecrosis of the jaw in cancer patients

Osteonecrosis of the jaw (ONJ), previously an entity associated with radiation therapy to the head and neck, has been observed in patients treated with bisphosphonates. Patients with metastatic breast cancer and myelomatous bone disease, commonly treated with high-potency nitrogen-containing bisphosphonates for a prolonged period of time, have the greatest risk of ONJ development. The reported frequency of ONJ ranges from 0.6% to 6.2% in breast cancer and from 1.7% to 15% in patients with multiple myeloma. Osteonecrosis of the jaw has also been observed in patients with other cancers such as prostate cancer and in benign bone disorders such as osteoporosis and Paget`s disease in which the incidence is low. Risk factors associated with the development of ONJ include dental extractions, length of bisphosphonate treatment, and the type of bisphosphonate used. In this review, we summarize the reported incidence and risk factors associated with ONJ.

Diets based on virgin olive oil or fish oil but not on sunflower oil prevent age-related alveolar bone resorption by mitochondrial-related mechanisms.

BACKGROUND/OBJECTIVES Aging enhances frequency of chronic diseases like cardiovascular diseases or periodontitis. Here we reproduced an age-dependent model of the periodontium, a fully physiological approach to periodontal conditions, to evaluate the impact of dietary fat type on gingival tissue of young (6 months old) and old (24 months old) rats. METHODS/FINDINGS Animals were fed life-long on diets based on monounsaturated fatty acids (MUFA) as virgin olive oil, n-6 polyunsaturated fatty acids (n-6PUFA), as sunflower oil, or n-3PUFA, as fish oil. Age-related alveolar bone loss was higher in n-6PUFA fed rats, probably as a consequence of the ablation of the cell capacity to adapt to aging. Gene expression analysis suggests that MUFA or n-3PUFA allowed mitochondria to maintain an adequate turnover through induction of biogenesis, autophagy and the antioxidant systems, and avoiding mitochondrial electron transport system alterations. CONCLUSIONS The main finding is that the enhanced alveolar bone loss associated to age may be targeted by an appropriate dietary treatment. The mechanisms involved in this phenomenon are related with an ablation of the cell capacity to adapt to aging. Thus, MUFA or n-3PUFA might allow mitochondrial maintaining turnover through biogenesis or autophagy. They might also be able to induce the corresponding antioxidant systems to counteract age-related oxidative stress, and do not inhibit mitochondrial electron transport chain. From the nutritional and clinical point of view, it is noteworthy that the potential treatments to attenuate alveolar bone loss (a feature of periodontal disease) associated to age could be similar to some of the proposed for the prevention and treatment of cardiovascular diseases, a group of pathologies recently associated with age-related periodontitis.

Accurate Approach in the Treatment of Oral Bisphosphonate-Related Jaw Osteonecrosis

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is not completely understood and difficult to treat. Even though the occurrence of BRONJ is mainly related to the therapy with intravenous bisphosphonates (BPs), this article reports a case of long-term oral BP use and BRONJ occurrence. In addition, a literature review provides some additional information about BPs, BRONJ, and also a guideline for the prevention and treatment of BRONJ stages. A 79-year-old patient presented intense and persistent pain, purulent secretion, and exposed bone at the right side of the lower jaw. Thus, she was submitted to anamnesis, radiologic and tomographic examinations, and bacterial culture and sensitivity tests. These procedures were followed by surgical debridement of the bone and surrounding tissues/cyst and antibiotic prescription and histopathologic analysis of the fragments. Together, the examinations performed showed the occurrence of stage 2 BRONJ. Moreover, the antibiotic prescription, discontinuation of oral BP, and surgical procedures ensure that the patient had no more symptoms. Therefore, considering the presented case, we believe that an accurate approach is promising to diagnose and treat stage 2 BRONJ and other associated pathologic findings.

Evaluation of two morphometric methods of bone loss percentages caused by periodontitis in rats in different locations

Objective: The present study evaluated morphometrically bone loss percentages in experimental periodontitis in rats, comparing different locations (lingual mandible, palatal maxilla and buccal maxilla) and two evaluation methods (distance and area methods). Material and Methods: Ligatures were placed around the maxillary right second molar and around the mandibular right first molar in 14 female Wistar rats. The contralateral molars served as intragroup control. After 4 weeks, the rats were sacrificed and their mandible and maxilla were removed. The specimens were dissected and stained with methylene blue dye. Bone loss was evaluated by two different methods on the surfaces of the defleshed jaw. In the first method, the distance from the cementoenamel junction (CEJ) to the alveolar bone crest was measured in the roots of teeth associated with ligature. In the second method, the area of bone loss was determined using the alveolar tissue bone, CEJ and the proximal region of roots associated with the ligature as reference. The data were converted to bone loss percentages caused by ligature: (ligated - unligated) x 100/ligated. Results: When comparing the distance and area methods, no statistically significant difference was observed (p>0.05). Both methodologies indicated that the maxilla presented greater bone loss than the mandible and it was more accentuated on the buccal side than on the palatal side (p<0.05). Conclusions: The findings of this study show that both the area and the distance methods can be used to evaluate bone loss caused by ligature placement in rats, and suggest applying the morphometric methodology to the maxilla on the buccal side.