Os fatores clássicos e a falha dos implantes dentários: qual o significado estatístico para a prática clínica? / On classic factors and dental implant failures: what is the statistical significance for the daily practice?

Objetivo: identificar quais dos fatores clássicos (material, desenho, superfície do implante, hospedeiro, técnica cirúrgica, protocolo de carga) possuem significado estatístico no prognóstico dos implantes. Material e métodos: uma busca eletrônica foi realizada no sistema PubMed/Medline até junho de 2015 com palavras-chave representativas dos estimadores, combinadas por operadores booleanos. Foram incluídos estudos clínicos contendo amostras com pelo menos 50 pacientes e 100 implantes, mínimo de um ano de acompanhamento, apresentando os estimadores obtidos através de modelo de Cox (Hazard ratio) ou regressão logística (Odds ratio, Risk ratio). O desfecho primário foi a falha do implante. Resultados: das 871 referências iniciais, foram selecionadas 20 após leitura integral, com mais de dez mil pacientes e mais de 30 mil implantes. Nos artigos com modelo de Cox, foram identificados o tabagismo (valores entre 1,04 e 3,9), o diâmetro (valores HR entre 1,72 e 6,35) e o comprimento (valores HR entre 0,8 e 2,7) do implante, as técnicas cirúrgicas específicas para melhorar o leito receptor (HR entre 2 e 5), os protocolos de carga (HR entre 0,1 e 9,7), o operador (HR=4,2; um estudo) e a maxila (HR=10; um estudo). Nos artigos com regressão logística, foram identificados os maiores valores de risco para implantes de largo diâmetro (OR=4,25; um estudo), implantes colocados na região posterior da maxila (OR=6,83; um estudo) e ausência de gengiva queratinizada (OR=4,7; um estudo). Conclusão: os fatores têm frequência variada, dependem da homogeneidade das amostras e nem sempre demonstram significado estatístico. Possíveis explicações podem ser atribuídas para as falhas. Mesmo assim, a documentação clínica detalhada continua fundamental para anteciparmos problemas em áreas estratégicas.

Objective: to identify which of the classic factors (implant material, design, surface; host, surgical technique, loading protocol) can have a statistical significance on dental implant prognosis. Material and methods: an electronic search at the PubMed/Medline was made until June 2015 with representative keywords combined by Boolean operators. Clinical studies with at least 50 patients and 100 implants, 1 year of follow-up, having statistical estimators such as Cox model (Hazard ratio) or logistic regression (Odds ratio, Risk ratio) analyses were included. The primary outcome was implant failure. Results: of the 871 retrieved records, 20 references were finally selected, summing up more than 10 thousand patients and 30 thousand dental implants. For articles using the Cox´s model, tobacco (HR values between 1.04 to 3.9), diameter (HR between 1.72 to 6.35), and implant length (HR between 0.8 to 2.7); specific surgical techniques to improve the recipient bed (HR between 2 and 5), loading protocols (HR from 0.1 to 9.7), the operator (HR=4.2, one study), and the maxillary arch (HR=10, 1 study) were identified. For articles containing logistic regression, the highest chance values were identified for large diameter implants (OR=4.25, one study), implants at the posterior maxillary region (OR=6.83, one study), and the lack of keratinized gingiva (OR=4.7, one study). Conclusion: these factors have a varied frequency, depend on sample´s homogeneity, and not always provide statistical meaning. Possible explanations can be attributed to failures. Even thus, a detailed clinical documentation remains mandatory to anticipate problems in strategic areas.

In vitro sealing ability of two materials at five different implant-abutment surfaces.

BACKGROUND: The aim of the present study was to test the sealing ability of two materials at five different implant-abutment surfaces. METHODS: In the first phase, 2 mul brain-heart infusion (BHI) broth was deposited into the implant wells and glass culture tubes. A varnish or silicon sealant was applied at the cervical implant portion of experimental groups. The control group remained unexposed. The abutments were torque-tightened to 20 Ncm with a manual torque driver. Implants were immersed in 4 ml BHI broth at 37 degrees C for 2 hours to exclude contamination. In the second phase, 100 mul Enterococcus faecalis American Type Culture Collection (ATCC) strain 29212 was deposited into the glass culture tubes. After periods of 7, 14, 21, 35, 49, and 63 days, the sealing capacity was checked. Abutments were removed, and a sterile paper cone collected material inside implant bodies. This material was transferred to new tubes with BHI to verify the presence of cloudy broths within 24 to 48 hours. RESULTS: There were no statistically significant differences between the two materials for each time period (Fisher exact test; P >0.05). Group E showed the least level of sealing ability (six implants contaminated), whereas group T showed the highest level (only two implants). CONCLUSIONS: 1) Materials tested were not able to prevent contamination over 63 days. 2) Bacterial contamination was verified after 14 and 35 days in the control and experimental groups, respectively. 3) Although materials tested had demonstrated similar sealing capacities, dental implants showed bacterial contamination regardless of their external or internal hexagonal configurations.