Impact of hyperglycemia and treatment with metformin on ligature-induced bone loss, bone repair and expression of bone metabolism transcription factors.

This study evaluated the influence of type 2 diabetes mellitus on bone loss, bone repair and cytokine production in hyperglycemic rats, treated or not with metformin. The animals were distributed as follow: Non-Hyperglycemic (NH), Non Hyperglycemic with Ligature (NH-L), Treated Non Hyperglycemic (TNH), Treated Non Hyperglycemic with Ligature Treated (TNH-L), Hyperglycemic (H), Treated Hyperglycemic (TH), Hyperglycemic with Ligature (H-L), Treated Hyperglycemic with Ligature (TH-L). At 40th day after induction of hyperglycemia, the groups NH-L, TNH-L, H-L, TH-L received a ligature to induce periodontitis. On the 69th, the TNH, TNH-L, TH, TH-L groups received metformin until the end of the study. Bone repair was evaluated at histometric and the expression levels of Sox9, RunX2 and Osterix. Analysis of the ex-vivo expression of TNF-α, IFN-γ, IL-12, IL-4, TGF-ß, IL-10, IL-6 and IL-17 were also evaluated. Metformin partially reverse induced bone loss in NH and H animals. Lower OPG/RANKL, increased OCN and TRAP expression were observed in hyperglycemic animals, and treatment with metformin partially reversed hyperglycemia on the OPG/RANKL, OPN and TRAP expression in the periodontitis. The expression of SOX9 and RunX2 were also decreased by hyperglycemia and metformin treatment. Increased ex vivo levels of TNF-α, IL-6, IL-4, IL-10 and IL-17 was observed. Hyperglycemia promoted increased IL-10 levels compared to non-hyperglycemic ones. Treatment of NH with metformin was able to mediate increased levels of TNF-α, IL-10 and IL-17, whereas for H an increase of TNF-α and IL-17 was detected in the 24- or 48-hour after stimulation with LPS. Ligature was able to induce increased levels of TNF-α and IL-17 in both NH and H. This study revealed the negative impact of hyperglycemia and/or treatment with metformin in the bone repair via inhibition of transcription factors associated with osteoblastic differentiation.

As avaliações longitudinais de cinco anos em próteses cerâmicas totais fixas implantossuportadas são escassas na literatura: uma revisão sistemática / Five-year longitudinal evaluations on implant-supported total fi xed ceramic prostheses are scarce in the literature: a systematic review

Objetivo: a objetivo desta revisão sistemática foi avaliar estudos clínicos e as taxas de sucesso e complicações protéticas das próteses fixas totais cerâmicas implantossuportadas em pacientes totalmente desdentados, após um período de acompanhamento mínimo de 5 anos. Material e métodos: a pesquisa bibliográfica foi realizada usando as bases de dados eletrônicas Medline/PubMed, entre 1980 a 2015, para estudos clínicos em língua inglesa relatando as complicações protéticas e implantares. Os termos de pesquisa que foram utilizados, isoladamente ou em combinação foram implant-supported restoration, prosthodontic complications, technical complications, mechanical complications, dental implants, screw complications, edentulous arch, metal framework fracture, restoration, acrylic veneer fracture, ceramic veneer fracture, biologic complications e edentulous arch. Resultados: dos 181 artigos recuperados, apenas três estudos cumpriram os critérios de inclusão para esta revisão, sendo três estudos prospectivos. As complicações biológicas e técnicas em implantes e próteses foram identificadas e registradas, incluindo: fraturas dos materiais de suporte da estrutura/recobrimento, soltura do parafuso da prótese e/ou parafuso do pilar, fratura do parafuso protético e/ou parafuso do pilar, deficiências estéticas e desgaste do material. Conclusão: dentro dos limites desta revisão sistemática, os estudos sobre materiais cerâmicos com cinco anos ou mais de acompanhamento são escassos ou inexistentes sugerindo cautela na utilização desse tipo de restauração implantossuportada.

Objective: the objective of this systematic review was to access the clinical studies and as success rates and prosthetic complications of total fi xed ceramic prostheses implanted in fully edentulous patients after a minimum follow-up period of 5 years. Material and methods: a literature search was conducted using Medline/PubMed electronic databases from 1980 to 2015 for English-language clinical studies reporting as prosthetic and implant complications. "Technical complications", "mechanical complications", "dental implants", "screw complications", "edentulous arch", "technical complications", "technical complications". "Fracture of metal structure", "restoration", "acrylic veneer fracture", "ceramic veneer fracture", "biological complications" and "edentulous arch". Results: from the 181 articles retrieved, only 3 studies fullfi lled the inclusion criteria for this review, being prospective studies. Such biological and technical complications in implants and prostheses were identifi ed and recorded, including: structure/veneering material fractures, prosthetic screw loosening and/or abutment screw, prosthetic and/or abutment screw fracture, defi cient esthetics, and material wear. Conclusion: within the limits of this systematic review, studies on ceramic materials with 5 years of follow-up are scarce or non-existent suggesting caution in the use of this type of implant-supported restoration.