Caracterização das alterações teciduais em dois modelos de indução de doença periodontal experimental em camundongos

Pós-graduação em Odontologia - FOAR

Comparison of changes in dental and bone radiographic densities in the presence of different soft-tissue simulators using pixel intensity and digital subtraction analyses

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

The Relationship between Biofilm and Physical-Chemical Properties of Implant Abutment Materials for Successful Dental Implants

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

Longevity of dental implants in type IV bone: a systematic review

Bone quality and quantity are important factors with regard to the survival rate of dental implants. The aim of this study was to conduct a systematic review of dental implants inserted in low-density bone and to determine the survival rate of dental implants with surface treatments over time. A systematic review of the literature was undertaken by two independent individuals; the Medline/PubMed database was searched for the period July 1975 to March 2013. Relevant reports on bone quality and osseointegration of dental implants were selected. The search retrieved 1018 references, and after inclusion and exclusion criteria were applied, 19 studies were selected for review. A total of 3937 patients, who had received a total of 12,465 dental implants, were analyzed. The survival rates of dental implants according to the bone density were: type I, 97.6%; type II, 96.2%; type III, 96.5%; and type IV, 88.8%. The survival rate of treated surface implants inserted in low-density bone was higher (97.1%) than that of machined surface implants (91.6%). Surface-treated dental implants inserted in low-density bone have a high survival rate and may be indicated for oral rehabilitation. However, more randomized studies are required to better evaluate this issue.

Healing Process of Autogenous Bone Graft in Spontaneously Hypertensive Rats Treated With Losartan: An Immunohistochemical and Histomorphometric Study

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

Influence Analysis of Cleft Type and Supernumerary Teeth Eruption in the Prognosis of Bone Graft in Patients With Cleft Palate

Objective: The aim of this study was to investigate the influence of cleft type and supernumerary tooth eruption on the treatment of palatal clefts with alveolar bone grafts.Materials and Methods: In this article, medical records of 40 patients with palatal clefts and associated supernumerary teeth who were treated with alveolar bone grafting in the Hospital for Craniofacial Anomalies Rehabilitation were assessed. The patients were studied to assess the influence of supernumerary teeth and the cleft severity on the prognosis of the alveolar bone graft.Results: Forty medical records were included in the assessment. When the teeth in the cleft had an anatomic shape close to canine, we called them precanine. When they were very small or malformed, we called them anomalous lateral incisors. The teeth studied showed good prognoses and were more expressive in the preforaminal clefts (87.5%) than in the transforaminal ones (62.5%). Moreover, the transforaminal clefts presented a higher percentage in satisfactory and poor prognoses (37.5%). The authors found that supernumerary teeth influenced the maintenance of alveolar bone graft height and that transforaminal clefts presented a worse prognosis than preforaminal clefts.

Doença periodontal em cães

Periodontal disease affects the periodontum which are tissues that support and protect the tooth and are composed by the gingiva, alveolar bone, cementum and periodontal ligament. Lesions in the periodontum have as main etiologic agent the presence of plaque or biofilm, which is formed in 24 hours and, basically, it consists of microorganisms surrounded by some bacteria rich matrix products and salivary glycoproteins. Gingivitis is the first clinical manifestation of periodontal disease and it is reversible if the etiologic agent (plaque) is removed. However, if it is not treated or controlled, it will lead to an irreversible periodontitis, and even evolve into alveolar bone, tissue destruction and, eventually, tooth loss

Efeito da aPDT na osseointegração de implantes em alvéolos contaminados

Objective: The aim of this study is to evaluate by histometric and immunohistochemistry analysis the effects of antimicrobial photodynamic therapy (aPDT) in alveolar prior to placement of mini-implants in animals with or without induced periodontal disease. Material and method: Thirty-two rats were used. Periodontal disease (PD) was induced by ligature in the lower left first molar. After 7 days of PD evolution, it was performed removal of the ligature and extraction of the left lower first molars in all animals. Thus, animals were divided into 2 groups (n=16) according to the treatments in the dental alveolus before immediate implant installation: MD (control) : mechanical debridement (MD), irrigation with 1 ml of saline solution followed by implant installation; aPDT- MD, irrigation with 1 ml of Toluidine Blue-O and low intensity laser (LLLT) and implant installation. Eight animals from each group were euthanized at 15 and 30 days after the installation of mini-implants. Specimens were processed for histologic, immunohistochemical and histometric analysis. The histometric data were processed for statistical analysis (Kruskall-Wallis and Dunn test; p <0.05). Result: In treatment analysis, results indicated that there was a greater BIC in implants installed in uncontaminated alveolus treated with a PDT ( p<0,05) and greater imuno-reactivity to OPG in bone issue treated with aPDT. Conclusion: The aPDT proved to be effective in bone loss control in no contaminated area and it has increased the bone loss and metabolic activity in alveolus irradiated prior to implant installation.

RANKL expression is differentially modulated by TLR2 and TLR4 signaling in fibroblasts and osteoblasts

Resident, non-immune cells express various pattern-recognition receptors and produce inflammatory cytokines in response to microbial antigens, during the innate immune response. Alveolar bone resorption is the hallmark of destructive periodontitis and it is caused by the host response to bacteria and their mediators present on the biofilm. The balance between the expression levels of receptor activator of nuclear factorkappa B ligand (RANKL) and osteoprotegerin (OPG) is pivotal for osteoclast differentiation and activity and has been implicated in the progression of bone loss in periodontitis. To assess the contribution of resident cells to the bone resorption mediated by innate immune signaling, we stimulated fibroblasts and osteoblastic cells with LPS from. Escherichia coli (TLR4 agonist), Porphyromonas gingivalis (TLR2 and -4 agonist), and interleukin-1 beta (as a control for cytokine signaling through Toll/IL-1receptor domain) in time-response experiments. Expression of RANKL and OPG mRNA was studied by RT-PCR, whereas the production of RANKL protein and the activation of p38 MAPK and NF-kB signaling pathways were analyzed by western blot. We used biochemical inhibitors to assess the relative contribution of p38 MAPK and NF-kB signaling to the expression of RANKL and OPG induced by TLR2, -4 and IL1β in these cells. Both p38 MAPK and NFkB pathways were activated by these stimuli in fibroblasts and osteoblasts, but the kinetics of this activation varied in each cell type and with the nature of the stimulation. E. coli LPS was a stronger inducer of RANKL mRNA in fibroblasts, whereas LPS from P. gingivalis downregulated RANKL mRNA in periodontal ligament cells but increased its expression in osteoblasts. IL-1β induced RANKL in both cell types and without a marked effect on OPG expression. p38 MAPK was more relevant than NF-kB for the expression of RANKL and OPG in these cell types.

Fractal dimension of the mandibular trabecular bone measured on digital and digitized images.

Aims: This study compared fractal dimension (FD) values on mandibular trabecular bone in digital and digitized images at different spatial and contrast resolutions. Materials and Methods: 12 radiographs of dried human mandibles were obtained using custom-fabricated hybrid image receptors composed of a periapical radiographic film and a photostimulable phosphor plate (PSP). The film/ PSP sets were disassembled, and the PSPs produced images with 600 dots per inch (dpi) and 16 bits. These images were exported as tagged image file format (TIFF), 16 and 8 bits, and 600, 300 and 150 dpi. The films were processed and digitized 3 times on a flatbed scanner, producing TIFF images with 600, 300 and 150 dpi, and 8 bits. On each image, a circular region of interest was selected on the trabecular alveolar bone, away from root apices and FD was calculated by tile counting method. Two-way ANOVA and Tukey’s test were conducted to compare the mean values of FD, according to image type and spatial resolution (α = 5%). Results: Spatial resolution was directly and inversely proportional to FD mean values and standard deviation, respectively. Spatial resolution of 150 dpi yielded significant lower mean values of FD than the resolutions of 600 and 300 dpi ( P < 0.05). A nonsignificant variability was observed for the image types ( P > 0.05). The interaction between type of image and level of spatial resolution was not signi fi cant (P > 0.05). Conclusion: Under the tested, conditions, FD values of the mandibular trabecular bone assessed either by digital or digitized images did not change. Furthermore, these values were in fluenced by lower spatial resolution but not by contrast resolution.

Detecção de Periodontopatógenos, Glicoproteína Emmprin (Cd-147) e sua correlação com MMP-2 e MMP-9

Periodontitis is an infectious disease characterized by the secretion of a variety of inflammatory mediators that lead to destruction of tooth supporting tissues, including the possible loss of alveolar bone, in association with infection with multiple species of bacteria. It is estimated that more than 400 species colonize the biofilm and some oral species related to periodontal disease is present in the subgingival including P. gingivalis, T. forsythia and T. denticola. However, other organisms may be related of this disease, as Filifactor allocis and Prevotella tannerae. These microorganisms and subproducts such as endotoxins released into the extracellular lead to the stimulation of metalloproteinase inducer glycoprotein (EMMPRIN, CD-147), which stimulates the release of MMPs by host cells, like fibroblasts and endothelial cells, thus leading to tissue destruction. The objective of this study was to detect F. allocis, P. tannerae, T. denticola and the glycoprotein EMMPRIN (CD-147) and its correlation with MMP-2 and MMP-9 in subgingival fluid samples of patients with chronic periodontitis. Fluids were collected from healthy and disease subgingival sites of 20 healthy individuals before basic periodontal treatment and after of 60 days of treatment. Their DNAs were extracted and portions of the 16S gene were amplified and performed conventional PCR. For immunological analysis and quantification of EMMPRIN (CD-147), MMP-2 and MMP-9 was used ELISA-Sandwich. Results demonstrated that the disease group showed significantly high amounts of T. denticola, F. alocis and P. tannerae when compared with health sites. MMP-2 and MMP-9 were detected in high concentrations with statistically significantly reduction after periodontal treatment to MMP-2, but without correlation with EMMPRIN.

Efeito da ovariectomia e da reposição hormonal no reimplante dentário imediato: análise histomorfométrica e imunoistoquímica em ratas

Pós-graduação em Odontologia - FOA

Survival rate of osseointegrated implants in atrophic maxillae grafted with calvarial bone: a retrospective study

The aim of this study was to evaluate the clinical survival rate of osseointegrated implants placed in the atrophic maxilla that has been reconstructed by means of autogenous bone grafts harvested from a cranial calvarial site. Further, we sought to analyse the level of pen-implant bone after prosthetic rehabilitation and to determine subjective patient satisfaction with the treatment performed. This study conformed to the STROBE guidelines regarding retrospective studies. Twenty-five patients who had received osseointegrated implants with late loading in the reconstructed atrophic maxilla were included in the study. The survival rate and level of pen-implant bone loss were evaluated. A questionnaire related to the surgical and prosthetic procedures was completed. The observed implant survival rate was 92.35%. The mean bone loss recorded was 1.76 mm in the maxilla and 1.54 mm in the mandible. The results of the questionnaire indicated a high level of patient satisfaction, little surgical discomfort, and that the patients would recommend the procedure and would undergo the treatment again. From the results obtained, it is concluded that the cranial calvarial site is an excellent donor area; calvarial grafts provided stability and maintenance of bone volume over the course of up to 11 years.

Porphyromonas gingivalis stimulates bone resorption by enhancing RANKL (Receptor Activator of NF-κB Ligand) through activation of toll-like receptor 2 in osteoblasts

Periodontitis has been associated with rheumatoid arthritis. In experimental arthritis, concomitant periodontitis caused by oral infection with Porphyromonas gingivalis enhances articular bone loss. The aim of this study was to investigate how lipopolysaccharide (LPS) from P. gingivalis stimulates bone resorption. The effects by LPS P. gingivalis and four other TLR2 ligands on bone resorption, osteoclast formation, and gene expression in wild type and Tlr2-deficient mice were assessed in ex vivo cultures of mouse parietal bones and in an in vivo model in which TLR2 agonists were injected subcutaneously over the skull bones. LPS P. gingivalis stimulated mineral release and matrix degradation in the parietal bone organ cultures by increasing differentiation and formation of mature osteoclasts, a response dependent on increased RANKL (receptor activator of NF-κB ligand). LPS P. gingivalis stimulated RANKL in parietal osteoblasts dependent on the presence of TLR2 and through a MyD88 and NF-κB-mediated mechanism. Similarly, the TLR2 agonists HKLM, FSL1, Pam2, and Pam3 stimulated RANKL in osteoblasts and parietal bone resorption. LPS P. gingivalis and Pam2 robustly enhanced osteoclast formation in periosteal/endosteal cell cultures by increasing RANKL. LPS P. gingivalis and Pam2 also up-regulated RANKL and osteoclastic genes in vivo, resulting in an increased number of periosteal osteoclasts and immense bone loss in wild type mice but not in Tlr2-deficient mice. These data demonstrate that LPS P. gingivalis stimulates periosteal osteoclast formation and bone resorption by stimulating RANKL in osteoblasts via TLR2. This effect might be important for periodontal bone loss and for the enhanced bone loss seen in rheumatoid arthritis patients with concomitant periodontal disease.

Segmental osteotomy for the correction of a malpositioned single implant: an 8-year follow-up

This case report is an 8-year follow-up of a malpositioned single implant, which was treated with segmental osteotomy, to confirm the treatment's characteristics, indications, and advantages. Deep buccal positioning of an endosseous implant placed in the maxillary left central incisor area did not permit acceptable prosthetic rehabilitation, despite its favorable bone insertion with no significant marginal bone loss. The surgical procedure included osteotomy and block movement performed toward the lingual and cervical position, fixed with a provisional prosthesis and miniplates and mini-implants. A connective tissue graft was necessary for esthetics optimization and was performed in a second stage. Advantages including the prevention of alveolar ridge damage, the improvement of gingival contour, and the use of an already integrated implant are presented. Clinically satisfactory hard and soft tissue stability permitted us to consider segmental surgery as a reliable alternative for malpositioned osseointegrated implants.