Influence of Estrogen Deficiency on Bone Around Osseointegrated Dental Implants: An Experimental Study in the Rat Jaw Model

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

Data collection on bone density of mandibular alveolar bone on a Hounsfield scale of the dental apex of the cranial root of the first inferior molar in dogs using computed tomography at FMVZ-UNESP

The head is the most important and specialized region in the body because it contains a range of specialized organs and, because it has interconnections between specialized organs, there is a great overlap of images. Thus, computed tomography (CT) helps in diagnosing diseases in this region, such as oral conditions, as they provide millimetric slices or cuts and demonstrate the relationship between the various anatomical structures involved, in volume and depth. Within dentistry, CT helps in the identification of pathological processes such as infection, tumors, visualization of embedded teeth and bone bed. This study aimed to assess the density of the mandibular alveolar bone at a determined point to later predict how periodontal disease is involved in bone resorption. For this, we performed a blind retrospective study (n = 124) of the CT scan files of dog skulls at FMVZ-UNESP in order to determine the density of the jaw bone using a Hounsfield scale, in the region of the dental apex of the cranial root of the first molar tooth in dogs. The results obtained were evaluated using mean and standard deviation (27.28 +/- 9.53 HU) in order to predict the normal density of the mandibular alveolar bone in the studied region. Thus, this data analysis allows a more concise evaluation of bone resorption of mandibular alveolar bone and, therefore, provides an adequate surgical planning in cases of osteosynthesis given mainly by the presence of installed periodontal disease.

Surto de abscesso mandibular por Pseudomonas aeruginosa em ovinos

Descreve-se um surto de abscesso mandibular em ovelhas da raça Bergamácia no município de Botucatu, estado de São Paulo. do rebanho de 120 animais, 35 apresentaram aumento de volume mandibular com a presença de nódulos únicos, de consistência pétrea, de diferentes tamanhos, fistulados ou não e sem indicativos de inflamação dos tecidos moles adjacentes. Os animais eram criados em pasto de Panicum maximum cv. Tanzânia com água e sal mineral ad libitum e everminados, via oral, com pistolas dosificadoras. O material para diagnóstico microbiológico e antibiograma foi coletado de cinco animais acometidos, por punção e aspiração dos nódulos. Dos 35 animais acometidos, 19 foram submetidos ao exame radiográfico, um ao exame tomográfico e outro à biópsia óssea da região submandibular. O único ovino que morreu, encontrava-se em estado de caquexia provavelmente devido à localização do aumento de volume que afetou a implantação dos dentes molares daquela região impedindo a apreensão e mastigação adequadas levando a perda da condição corporal e morte. Ao exame necroscópico, observaram-se áreas de necrose caseosa na mandíbula direita de onde isolou-se Pseudomonas aeruginosa. O tratamento utilizado foi baseado na aplicação de iodeto de sódio a 10% por via intramuscular e antibioticoterapia segundo antibiograma com enrofloxacina por via intramuscular, porém com pouca eficácia. Diante do quadro clínico, dos dados de anamnese, da localização das lesões no tecido ósseo mandibular, do resultado do cultivo microbiológico, das alterações radiográficas e tomográficas foi feito o diagnóstico de abscesso mandibular causado por Pseudomonas aeruginosa.

Experimental development of bisphosphonate-related osteonecrosis of the jaws in rodents

Osteonecrosis of the jaw (ONJ) following the use of bisphosphonates has become of increased interest in the scientific community, due in particular to its as-yet-unsolved pathogenesis. An experimental model of ONJ was induced in normal male rats [alendronate (ALN); 1 mg/Kg/day; n = 10] and matched controls (saline solution; n = 10). After 60 days of drug treatment, all animals were subjected to extractions of the left first lower molars and were euthanized at 3 and 28 days postsurgery. The following analyses were performed: (i) descriptive and quantitative (scores) histological evaluation, (ii) stereometry of distal sockets and (iii) biochemical measurement of C-telopeptide cross-linked collagen type I (CTX) and bone-specific alkaline phosphatase (BALP). The results showed that 28 days postsurgery the animals treated with ALN had areas of exposed and necrotic bone, associated with significant infection, especially in the interalveolar septum area and crestal regions, compared with controls. The levels of CTX, BALP and bone volume, as well as the degrees of inflammation and vascularization, were significantly reduced in these animals. Therefore, analysis of the data presented suggests that ALN therapy is associated with the development of osteonecrosis in the jaws of rodents after tooth extraction. © 2012 International Journal of Experimental Pathology.

Correlation between hand/wrist and panoramic radiographs in severe secondary hyperparathyroidism

Objectives: Hand/wrist and dental radiographs are important for osteoporosis analysis in secondary hyperparathyroidism (SHPT). This study evaluated whether a correlation exists between the effects of the disease on the hands and jaws, and investigated the association between osteoporosis progression in the hands and parathyroid hormone (PTH) levels in chronic kidney disease (CKD) patients. Materials and methods: Four panoramic radiographic parameters (mental index, mandibular cortical index, trabecular bone pattern, and calcification/resorption) and four corresponding hand/wrist radiographic parameters (metacarpal cortical thickness, phalangeal cortical index, trabecular bone pattern, and calcification/resorption) were applied to investigate possible correlation between the effects of SHPT on the jaws and hands/wrists, by Spearman's correlation coefficient. PTH levels and the hand/wrist radiographic parameters were also tested by spearman's correlation coefficient (p < 0.05). The presence of brown tumors, vascular calcifications, and acroosteolysis on the hands was also evaluated. Results: Mandibular cortical index was strongly correlated with the phalangeal cortical index (p = 0.000). Phalangeal cortical index and trabecular bone pattern of hand/wrist correlated with PTH levels (0.002 and 0.000, respectively). Brown tumors occurred in four CKD patients, while both vascular calcifications and acroosteolysis were observed in 19 patients. Conclusion: There is a significant correlation between the morphological changes caused by secondary hyperparathyroidism in hand and jaw bones. The morphological status can be assessed using the mandibular cortical index, besides the phalangeal cortical index. The latter correlates well with parathyroid hormone levels of advanced chronic kidney disease. Clinical relevance: Panoramic images reveal morphological changes in the jaw bone, indicating likewise changes in the hand/wrist in severe secondary hyperparathyroidism. The severity of the bone changes may be a reflection of the parathyroid hormone levels in advanced chronic kidney disease. © 2012 Springer-Verlag.

Articulação temporomandibular: anatomia, dinâmica e disfunções temporomandibulares

This study gathered some of the most relevant researches already undertaken regarding the Temporomandibular Joint, presenting descriptions of its anatomy and dynamics, and relating them to the main aspects of joint dysfunctions. Literature recognizes that the Temporomandibular Joint, responsible for lower jaw movements, comprehends the skull base and the jaw bone. Its anatomy and dynamics are of great importance in order to understand the functions of Stomatognathic System as well as to study Temporomandibular Joint Dysfunction. The elements that compose this synovial joint and the bilateral characteristic confer eminent importance to the ATM before the skeleton head, the ability to perform broad movements and high complexity in its operation. It is accepted that the overload of one anatomical structure from the TMJ or other components of the Stomatognathic System leads to Temporomandibular Joint Dysfunctions. These disorders have different etiologies, ranging from malocclusion to emotional stress, and various forms of treatment, which are related in this study

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)

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.

Effects of simvastatin on bone regeneration in the mandibles of ovariectomized rats and on blood cholesterol levels.

The purpose of this study was to evaluate the effects of simvastatin on guided bone regeneration in the mandibles of ovariectomized rats, and to observe their blood cholesterol levels. Seventy female rats were divided into two groups: control and treated, both groups containing normal and ovariectomized rats. A month after ovariectomy a bone defect was created in the mandible, and was covered by a polytetrafluoroethylene membrane. The treated groups received simvastatin orally for 15 or 30 days. The rats were sacrificed 15, 30 or 60 days after surgery, at which time a blood sample was extracted for blood cholesterol level analysis and the mandible was extracted for densitometric, histological and morphometric analysis. All specimens underwent analysis of variance. The ovariectomized animals had higher cholesterol levels than the treated normal animals, and no significant difference was found between the different treatment periods and the sacrifice times. The densitometric, histological and morphometric analysis showed that the treated ovariectomized animals developed more new bone than the control ovariectomized rats, but no significant difference was observed between the treatment periods. It can be concluded that the deficiency of estrogen increased the level of blood cholesterol and that the simvastatin aided new bone formation in the ovariectomized animals.

Cocaine associated with onlay bone graft failure: A clinical and histologic report

This patient report presents an unusual onlay bone graft failure following local cocaine application. Three months after the bone grafting procedure performed in the anterior maxilla for bone volume augmentation, the bone graft was totally exposed in the oral cavity as a result of the rubbing of cocaine on the gingival tissue that covered the bone graft. A histologic view of the removed bone fragment presented not only an area of necrosis but also ample spaces filled with necrosis material and resorption areas. Dental practitioners need to be aware of this phenomenon because such patients often do not report the use of drugs, particularly cocaine. Copyright © 2005 by Lippincott Williams & Wilkins.

Histomorphometric evaluation of a threaded, sandblasted, acid-etched implant retrieved from a human lower jaw: A case report

The purpose of this study was to histomorphometrically evaluate the bone-to-implant contact and bone area around a titanium implant retrieved from a human lower jaw. A screw-shaped titanium implant (sandblasted and acid-etched surface) was removed from a 68-year-old male after having been in function for 40 months because of a fracture of the abutment screw. Following the implant removal, an undecalcified section was obtained. The histomorphometric analysis showed a rate of 75.40% of bone-to-implant contact and 89.30% of bone area filling within the limits of the implant threads. The surrounding bone healed in a well-organized pattern and could not be differentiated from the anginal alveolus. The histologic evidence showed a high degree of osseointegration in a threaded, sandblasted, and acid-etched implant retrieved from a human lower jaw after functional loading for 40 months. Copyright © 2005 by Lippincott Williams & Wilkins.

Prosthetic rehabilitation of a bone defect with a teeth-implant supported, removable partial denture

The use of teeth-implant, mucosa-supported removable dentures for rehabilitation of partially edentulous patients involves highly complex biomechanical aspects. This type of prosthesis associates 3 kinds of support that react differently to the functional and parafunctional forces developed in the oral cavity. Although the construction of removable partial dentures may seem paradoxical when osseointegrated implants are placed, in some cases, this option is an excellent alternative to solve difficulties related to the anatomic, biologic, psychomotor, and financial conditions of the patient. This article reports on a case in which a teeth-implant, mucosa-supported removable partial denture was the option of choice for a patient with financial and anatomic limitations, having a large structural loss of the residual alveolar ridge caused by trauma by a gunshot injury at the mandible. The 5-year follow-up did not reveal any type of biomechanical or functional problem. Copyright © 2006 by Lippincott Williams and Wilkins.