Does traumatic occlusal forces lead to peri-implant bone loss? A systematic review

Abstract Observational studies have indicated that crestal bone level changes at implants are typically associated with clinical signs of inflammation, but still mechanical overload has been described as possible factor leading to hard-tissue deficiencies at implant sites without mucosal inflammation. The aim of this paper was systematically review the literature regarding the possible effect of traumatic occlusal forces on the peri-implant bone levels. Literature search was conducted using PubMed, Scielo and Lilacs, including the following terms: oral OR dental AND implant$ AND (load OR overload OR excessive load OR force$ OR bruxism) AND (bone loss OR bone resorption OR implant failure$). Databases were searched for the past 10 years of publications, including: clinical human studies, either randomized or not, cohort studies, case control studies, case series and animal research. Exclusion criteria were review articles, guidelines and in vitro and in silico (finite element analysis) research, as well as retrospective studies. The PICO questions formulated was: "does traumatic occlusal forces lead to peri-implant bone loss?" The database searches as well as additional hand searching, resulted in 807 potentially relevant titles. After inclusion/exclusion criteria assessment 2 clinical and 4 animal studies were considered relevant to the topic. The included animal studies did not reveal an association between overload and peri-implant bone loss when lower overloads were applied, whereas in the presence of excessive overload it seemed to generate peri-implant bone loss, even in the absence of inflammation. The effect of traumatic occlusal forces in peri-implant bone loss is poorly reported and provides little evidence to support a cause-and-effect relationship in humans, considering the strength of a clinically relevant traumatic occlusal force.

Avaliacao in vitro da microdureza de cimentos de ionomero de vidro modificados por resina submetidos a biofilme de Candida albicans / In vitro evaluation of microhardness of resin-modifi ed glass ionomer cements subjected to a candida albicans biofilm

Objetivo: Analisar in vitro a influencia da presenca de um biofilme de Candida albicans na microdureza superficial de duas marcas de cimentos de ionomero de vidro modificados por resina encontrados no mercado, o Vitremer© e o Vitro Fill© LC. Metodo: Nove amostras de cada material foram confeccionadas utilizando-se moldes de plasticos, previamente padronizados. Os nove especimes de cada marca foram divididos em tresgrupos: G1 solucao salina; G2 BHI liquido sem C. albicans; G3 suspensao celular com 105 de leveduras/mL em BHI liquido e a inducao da formacao de biofilme ocorreu apos incubacao das placas a 37§C por 48 horas. Os especimes foram esterilizados atraves de oxido de etileno. Foi avaliada a microdureza Knoop (50g, 15s). Os resultados foram submeti dos a Analise de Variancia (ANOVA) e teste de Tukey (5%). Resultados: Os grupos G1 e G2 obtiveram valores medios de dureza (KHN) maiores que G3 para ambos os materiais testados. Comparando os grupos G2 e G3, os especimes de G3 apresentaram menor resistencia as indentacoes. Conclusao: Nas condicoes do estudo in vitro, o biofilme de Candida albicans apresentou potencial de reduzir a dureza superficial de dois ionomeros de vidro modificados por resina encontrados no mercado (Vitremer© e Vitro Fill LC©).

Objective: To assess in vitro the influence of the presence of a Candida albicans biofilm on the surface microhardness of two commercial brands of resin-modified glass ionomer cements, Vitremer© and Vitro Fill© LC. Method: Nine samples of each material were fabricated using standardized plastic molds. The nine specimens of each brand were assigned to three groups: G1: saline; G2: BHI broth without C. albicans; G3: cell suspension with 105 yeasts/mL in BHI broth. Induction of biofilm formation occurred after incubation of the plates at 37§C for 48 hours and the specimens were sterilized with ethylene oxide. Knoop microhardness was measured (50 g, 15 s). Data were subjected to ANOVA and Tukey test at 5% significance level. Results: G1 and G2 presented higher mean hardness values (KHN) than G3 for both tested materials. Comparing G2 and G3, G3?s specimens presented lower resistance to theindentations. Conclusion: Under the conditions of this in vitro study, the Candida albicans biofilm reduced the surface hardness of two commercially available resin-modified glass ionomer cements (Vitremer© and Vitro Fill LC©).