Diabetes triggers the loss of tooth structure associated to radiographical and histological dental changes and its evolution to progressive pulp and periapical lesions in rats.

OBJECTIVES: The aim of this study was to evaluate the putative influence of diabetes without metabolic control in the loss of tooth structure as well as histological changes in dentin and pulp tissue in rats. DESIGN: Diabetes was induced in Wistar rats (n=25) by intravenous administration of alloxan (42 mg/kg). Diabetic and non-diabetic control rats were evaluated at 1, 3, 6, 9 and 12 months of follow-up. In order to evaluate the presence and progression of dental caries and periapical lesions, hemimandibles were removed and submitted to radiographical, histological, and morphometrical procedures. RESULTS: Dental caries were detected after radiographical and histological evaluations in diabetic group from the third month of diabetes onset, increasing gradually in frequency and severity in periods. Diabetic rats dental pulps also presented significant reduction in volume density of collagen fibers and fibroblasts at third month, parallel with a trend towards the increase in inflammatory cells volume density. Diabetic rats presented a generalized pulp tissue necrosis after 6 months of diabetes induction. Moreover, periapical lesions were not detected in control group, while these lesions were observed in all rats after 3, 6, 9, and 12 months of diabetes induction. CONCLUSIONS: Uncontrolled diabetes seems to trigger the loss of tooth structure, associated to histological dental changes and mediates its evolution to progressive severe pulp and periapical lesions in rats. Therefore, diabetes may be considered a very important risk factor regarding alterations in dental pulp, development of dental caries, and periapical lesions.

Green Tea Modulates Cytokine Expression in the Periodontium and Attenuates Alveolar Bone Resorption in Type 1 Diabetic Rats.

UNLABELLED: Diabetes mellitus comprises a heterogeneous group of disorders with the main feature of hyperglycemia. Chronic hyperglycemia increases the severity of periodontal disease via an exacerbated inflammatory response, activated by advanced glycation end products and their receptor, RAGE. Therefore, anti-inflammatory agents represent potential inhibitors of this pathological interaction. In particular, green tea has been shown to possess anti-inflammatory properties mediated by its polyphenol content. OBJECTIVES: This study investigated the mechanisms by which green tea attenuates the spontaneous onset of diabetes-induced periodontitis. METHODS: Diabetes was induced in rats via a single intraperitoneal injection of streptozotocin (STZ). Diabetic and control animals were divided into water-treated and green tea-treated subgroups and were analyzed at 15, 30, 60 and 90 days after diabetes induction. Immunohistochemistry was performed to quantitatively evaluate tumor necrosis factor-α (TNF-α), receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG), interleukin-10 (IL-10) and runt-related transcription factor 2 (RUNX-2) expression in serial sections of each hemimaxilla. Morphometric measurements of the distance from the cementum-enamel junction (CEJ) of the superior distal root of the first molar to the alveolar bone crest (ABC) were performed to assess bone loss. RESULTS: Diabetes resulted in significant bone loss and alterations in the number of cells that stained positive for inflammatory mediators. In the diabetic rats treated with green tea, we observed a decreased number of cells expressing RANKL and TNF-α compared with that observed in the diabetic rats treated with water. Additionally, green tea increased the numbers of cells that stained positive for OPG, RUNX-2 and IL-10 in the diabetic rats. CONCLUSION: Green tea intake reduces expression of the pro-inflammatory cytokine TNF-α and the osteoclastogenic mediator RANKL to normal levels while increasing expression of the anti-inflammatory cytokine IL-10, the osteogenesis-related factor RUNX-2 and the anti-osteoclastogenic factor OPG. Therefore, green tea represents a potential therapeutic agent for the treatment of diabetes-related periodontal disease.

The effect of mouthwashes containing biguanides on the progression of erosion in dentin.

BACKGROUND: Dental erosion is caused by frequent exposure to acids without the involvement of microorganism. This study analyzed the effect of biguanides (polyhexamethylene biguanide - PHMB and chlorhexidine - CHX) on dentin erosion due to their possible influence on the enzymatic degradation of the demineralized organic matrix. METHOD: Sixty bovine dentin specimens were prepared. On both sides of their surface, nail varnish was applied to maintain the reference surfaces for the determination of dentin loss. Samples were cyclically de- and remineralized for 6 days. Demineralization was performed with a 0.87 M citric acid solution (6×5 min daily). Thereafter, samples were treated with distilled water (negative control), 0.12% CHX (positive control), 0.07% PHMB, Sanifill Perio Premium™ (0.07% PHMB plus 0.05% NaF), or F solution (0.05% NaF) for 1 min and then subjected to enzymatic challenge for 10 min using a bacterial collagenase (Clostridium hystoliticum, 100 µg/ml). Dentin loss was assessed using profilometry (µm) daily. Data were analyzed using 2-way repeated measures-ANOVA and Bonferroni's test (p < 0.05). RESULTS: Dentin loss progressed significantly for all groups during the 6 days. After the 3rd day, Sanifill Premium™, CHX, and PHMB significantly reduced dentin erosion compared to control. On the 6th day, the lowest mean (±SD) dentin loss was observed for Sanifill Perio Premium™ (94.4 ± 3.9 µm). PHMB and CHX led to intermediate dentin loss (129.9 ± 41.2 and 135.3 ± 33.5 µm, respectively) that was significantly lower than those found for negative control (168.2 ± 6.2 µm). F (157.4 ± 6.1 µm) did not significantly differ from negative control. CONCLUSIONS: Sanifill Perio Premium™ mouthwash has a good potential to reduce dentin loss, which might be associated with the presence of PHMB.

Assessment of new bone formation around titanium surface treated implants in diabetic rats / Neoformação óssea ao redor de implantes de titânio com superfície tratada inseridos em ratos diabéticos

Objective: This study aimed to compare the bone formation around titanium implants with machined and acid-etched surfaces, inserted in induceddiabetic rats and in non-diabetic rats, in an attempt to investigate whether there are differences in bone formation between this metaboliccondition and the use of different implant surfaces. Methods: Custom fabricated commercially pure solid cylinder titanium implants, machined and acid-etched surface were inserted in the femora of streptozotocin-induced diabetic rats (n=10) and non-diabetic rats (n=10). Morphometrical bone-implant contact percentage and bone area within the limits of the implant threads (BD) were performed at 21 days of healing. Results: Peri-implant tissue in machined implant showed intense new bone formation within all threads of the implants of the non-diabetic group (BIC= 82.8 ± 9.23 e BD = 38.7 ± 4.27) while diabetic group (BIC = 35.3 ± 9.4 and BD = 20.0 ± 3.8) exhibited small and immature bone formationwithin threads of the implants with thickness fibrous connective tissue interposition between bone-implant interface. In the acid-etchedsurface implants in both, diabetic and non-diabetic groups, the peri-implant tissue showed intense new bone formation within all threads ofthe implants with BIC = 74.4 ± 14.7 e BD = 35.4 ± 3.48 in non-diabetic group and BIC = 63.1 ± 12.9 e BD = 29.6 ± 4.9 in diabetic group.Conclusion: In machined surface implants the diabetes interfere negatively in osseointegration while acid-etched surface promoted major BIC and BD index, indicating its selective use in diabetic patients.

Objetivo: Comparar a formação óssea ao redor de implantes de superfície lisa e tratada, instalados em ratos diabético-induzidos e não-diabéticos,investigando se há diferenças na formação óssea entre os dois quadros metabólicos, melhora no padrão de osteogênese entre as diferentessuperfícies e, sua relação com o diabetes. Métodos: Foram instalados implantes de titânio de superfícies lisa e tratada, no fêmur de ratos diabético-induzidos com estreptozotocina (n=10) e não diabéticos (n=10).A Análise morfométrica da porcentagem de contato osso-implante (COI) foi realizada 21 dias após a cirurgia. Resultados: A neoformação óssea foi intensa ao redor dos implantes de superfície lisa nos ratos não-diabéticos (COI = 82.8 ± 9.23), enquanto que o grupo diabético exibiu pequena e imatura formação óssea (COI=35.3 ± 9.4), com interposição de tecido conjuntivo na interface osso-implante. Ao redor dos implantes com superfície tratada, ocorreu intensa neoformação óssea, tanto nos animais diabéticos (COI = 63.1 ± 12.9) como nos não-diabéticos, (COI = 74.4 ± 14.7). Conclusão: Nos implantes de superfície lisa, o diabetes interfere negativamente na osseointegração, enquanto que as superfícies tratadas com ácido promoveram maior contato osso-implante, indicando seu uso seletivo em pacientes diabéticos.

Spontaneous periodontitis development in diabetic rats involves an unrestricted expression of inflammatory cytokines and tissue destructive factors in the absence of major changes in commensal oral microbiota.

Diabetes mellitus is a heterogeneous group of disorders, in which hyperglycemia is a main feature. The objective was to evaluate the involvement of RAGE, inflammatory cytokines, and metalloproteinases in spontaneous periodontitis triggered by diabetes induction. Immunohistochemical procedures for MMP-2, MMP-9, TNF-α, IL-1ß, IL-6, RANKL, and RAGE were performed in rats after 1, 3, 6, 9, and 12 months of diabetes induction. Total DNA was extracted from paraffin-embedded tissues and evaluated by Real-TimePCR for 16S total bacterial load and specific periodontopathogens. Our data did not demonstrate differences in microbiological patterns between groups. In diabetic groups, an increase in RAGE-positive cells was detected at 6, 9, and 12 months, while TNF-alpha-stained cells were more prevalent at 6 and 12 months. In experimental groups, IL-ß-positive cells were increased after 12 months, IL-6 stained cells were increased at 9 and 12 months, and RANKL-positive cells at 9 months. Diabetes resulted in widespread expression of RAGE, followed by expression of proinflammatory mediators, without major alterations in oral microbial profile. The pervasive expression of cytokines suggests that spontaneous periodontitis development may be independent of microbial stimulation and may be triggered by diabetes-driven imbalance of homeostasis.

Análise da presença de citocinas no periodonto de ratos diabéticos tratados com chá verde / Cytokines expression analyses in periodontium of diabetic rats treated with green tea

As doenças periodontais (DPs) são alterações inflamatórias crônicas que acometem os tecidos de sustentação do órgão dental. A presença do diabetes é refletida em maior severidade e prevalência das DPs tanto em humanos quanto em modelos experimentais. Contudo, os mecanismos biológicos envolvidos no aumento da prevalência e da severidade permanecem pouco conhecidos. Desta forma, o objetivo deste estudo foi avaliar o número de células marcadas por imunohistoquímica para TNF-α, RANKL, OPG, IL-10 e para o fator de transcrição RUNX-2, na doença periodontal experimental decorrente da indução do diabetes em ratos. Além disso, avaliamos os possíveis efeitos do tratamento com chá verde sobre o periodonto dos animais. Inicialmente, os ratos (n=80) foram submetidos à indução do diabetes por administração intraperitoneal de estreptozotocina (50mg/kg) e, juntamente com o grupo controle (n=40), foram subdivididos em animais tratados com chá verde ou com água, acompanhados durante o período de 15, 30, 60 ou 90 dias. Após o sacrifício dentro do tempo determinado para cada grupo, as hemimaxilas coletadas passaram pelos procedimentos de imunohistoquímica. Os resultados revelaram que a presença do diabetes causou perda óssea alveolar, compatível com o desenvolvimento da doença periodontal e resultou em alterações significativas no número de células imunomarcadas para diferentes mediadores do processo inflamatório. Entretanto, o chá verde apresentou efeitos benéficos para o periodonto, alterando a marcação das citocinas envolvidas. Nos animais diabéticos, independente do tratamento, foi observado aumento estatisticamente significativo (p<0,05 ANOVA) no número de células imunomarcadas para TNF-α e RANKL. Inversamente, houve menor marcação para OPG (60 e 90 dias), RUNX-2 (30, 60 e 90 dias) e para IL-10 (30, 60 e 90 dias) nos animais que ingeriram água. Porém, os diabéticos tratados com chá não demonstraram diferenças significativas em relação ao seu respectivo controle...

Periodontal diseases (PD) are chronic inflammatory diseases leading the destruction of connective tissue and alveolar bone supporting the teeth. The establishment of diabetes increases PD prevalence and severity in humans and experimental model. However, biological mechanisms regarding to increase of prevalence and severity remains poorly known. The aim of this study was to evaluate the number of immuno-staining cells to TNF-α, RANKL, OPG, IL-10 and transcription factor RUNX-2 in experimental periodontal disease in diabetic rats. Furthermore, the possible green tea efects were evaluated in periodontiumof the rats. Diabetes was induced in Wistar rats (n=120) by intraperitoneal administration of 50 mg/kg ofstreptozotocin and together with control animals (n=80), the rats were subdivided in water or green tea treated group, that were analyzed at 15, 30, 60 and 90 days after diabetes induction. The animals were sacrificed and the hemimaxillae were removed and submitted to immunohistochemistry procedures. Our data demonstrated that diabetes induction and progression resulted in significant bone loss and alterations in number of immuno-staining cells to different mediators of inflammatory process. However, the green tea showed positive effects in periodontium through inflammation modulation. In diabetic rats, regardless of treatment, we observed an increased number of immuno-staining cells to TNF-α, IL-1b and RANKL (p<0,05 ANOVA). On the other hand, in water treated diabetic rats, there were a decreased number of immuno-staining cells to OPG (60 e 90 days), RUNX-2 (30, 60 e 90 days) and IL-10 (30, 60 e 90 days). However, the green tea treated rats did not showed statistical differences between control and experimental groups in those staining. When we compared both diabetic groups, green tea and water treated, the animals that drank the green tea showed decreased number of immuno-staining cells to TNF-α and RANKL(p<0,05 ANOVA) whereas the number...

Análise da presença de citocinas no periodonto de ratos diabéticos tratados com chá verde / Cytokines expression analyses in periodontium of diabetic rats treated with green tea

As doenças periodontais (DPs) são alterações inflamatórias crônicas que acometem os tecidos de sustentação do órgão dental. A presença do diabetes é refletida em maior severidade e prevalência das DPs tanto em humanos quanto em modelos experimentais. Contudo, os mecanismos biológicos envolvidos no aumento da prevalência e da severidade permanecem pouco conhecidos. Desta forma, o objetivo deste estudo foi avaliar o número de células marcadas por imunohistoquímica para TNF-α, RANKL, OPG, IL-10 e para o fator de transcrição RUNX-2, na doença periodontal experimental decorrente da indução do diabetes em ratos. Além disso, avaliamos os possíveis efeitos do tratamento com chá verde sobre o periodonto dos animais. Inicialmente, os ratos (n=80) foram submetidos à indução do diabetes por administração intraperitoneal de estreptozotocina (50mg/kg) e, juntamente com o grupo controle (n=40), foram subdivididos em animais tratados com chá verde ou com água, acompanhados durante o período de 15, 30, 60 ou 90 dias. Após o sacrifício dentro do tempo determinado para cada grupo, as hemimaxilas coletadas passaram pelos procedimentos de imunohistoquímica. Os resultados revelaram que a presença do diabetes causou perda óssea alveolar, compatível com o desenvolvimento da doença periodontal e resultou em alterações significativas no número de células imunomarcadas para diferentes mediadores do processo inflamatório. Entretanto, o chá verde apresentou efeitos benéficos para o periodonto, alterando a marcação das citocinas envolvidas. Nos animais diabéticos, independente do tratamento, foi observado aumento estatisticamente significativo (p<0,05 ANOVA) no número de células imunomarcadas para TNF-α e RANKL. Inversamente, houve menor marcação para OPG (60 e 90 dias), RUNX-2 (30, 60 e 90 dias) e para IL-10 (30, 60 e 90 dias) nos animais que ingeriram água. Porém, os diabéticos tratados com chá não demonstraram diferenças significativas em relação ao seu respectivo controle...

Periodontal diseases (PD) are chronic inflammatory diseases leading the destruction of connective tissue and alveolar bone supporting the teeth. The establishment of diabetes increases PD prevalence and severity in humans and experimental model. However, biological mechanisms regarding to increase of prevalence and severity remains poorly known. The aim of this study was to evaluate the number of immuno-staining cells to TNF-α, RANKL, OPG, IL-10 and transcription factor RUNX-2 in experimental periodontal disease in diabetic rats. Furthermore, the possible green tea efects were evaluated in periodontiumof the rats. Diabetes was induced in Wistar rats (n=120) by intraperitoneal administration of 50 mg/kg ofstreptozotocin and together with control animals (n=80), the rats were subdivided in water or green tea treated group, that were analyzed at 15, 30, 60 and 90 days after diabetes induction. The animals were sacrificed and the hemimaxillae were removed and submitted to immunohistochemistry procedures. Our data demonstrated that diabetes induction and progression resulted in significant bone loss and alterations in number of immuno-staining cells to different mediators of inflammatory process. However, the green tea showed positive effects in periodontium through inflammation modulation. In diabetic rats, regardless of treatment, we observed an increased number of immuno-staining cells to TNF-α, IL-1b and RANKL (p<0,05 ANOVA). On the other hand, in water treated diabetic rats, there were a decreased number of immuno-staining cells to OPG (60 e 90 days), RUNX-2 (30, 60 e 90 days) and IL-10 (30, 60 e 90 days). However, the green tea treated rats did not showed statistical differences between control and experimental groups in those staining. When we compared both diabetic groups, green tea and water treated, the animals that drank the green tea showed decreased number of immuno-staining cells to TNF-α and RANKL(p<0,05 ANOVA) whereas the number...

A importância da mucosa ceratinizada ao redor de implantes osseointegrados / The importance of the keratinized mucosa surrounding osseointegrated implants

A anatomia do tecido mole periimplantar é semelhante à do dente natural, uma vez que apresenta epitélio juncional e tecido conjuntivo. Entretanto, as fibras conjuntivas do dente (Sharpey) estão inseridas no osso e no cemento radicular, diferentemente das fibras que circundam o implante, pois essas apresentam uma disposição paralela em relação ao abutment (intermediário transmucoso). Portanto, o selamento periimplantar é estabelecido pela mucosa ceratinizada presente, por meio do tônus de suas fibras colágenas, proporcionando uma firme junção epitélio-implante. Assim, uma adequada faixa de mucosa ceratinizada é capaz de facilitar o controle de placa realizado pelo paciente; evita traumas no tecido mole (durante os procedimentos cirúrgicos e protéticos) e previne a migração apical da margem gengival, mantendo a homeostasia periimplantar e a estética. Enquanto não se tem um consenso na literatura sobre a quantidade adequada de zona de mucosa queratinizada em torno do implante, a presença desta mucosa parece trazer benefícios a prótese implantada.

The anatomy of soft tissue peri-implant is similar of the natural tooth in that there are connective-tissue attachment and juncional epithelial. However, the connective fibers of the tooth (Sharpey) are inserted in the bone and the cement of root, differently of the fibers that surround the implantation, therefore these present a parallel disposition in relation to abutment (intermediate transmucoso).Therefore, the sealing peri-implantar is established by the present keratinized mucosa by means of tonus of its collagens fibers, providing a firm junction epithelium-implant. Thus, one adjusted zone of keratinized mucosa is able to facilitate the plaque-control procedure, to prevent trauma in the soft tissue and to prevent the apical migration of the gingival edge, keeping the homeostasia periimplant and the aesthetic one. Until it isn’t consensus in literature about the quantity of adequate zone of keratinized mucosa around implants, the presence of this mucosa carries some benefits to implant prothesis.