Targeting implant-associated infections: titanium surface loaded with antimicrobial.

Implant devices have = proven a successful treatment modality in reconstructive surgeries. However, increasing rates of peri-implant diseases demand further examination of their pathogenesis. Polymicrobial biofilm formation on titanium surfaces has been considered the main risk factor for inflammatory processes on tissues surrounding implant devices, which often lead to implant failure. To overcome microbial accumulation on titanium surfaces biofilm targeting strategies have been developed to modify the surface and incorporate antimicrobial coatings. Because antibiotics are widely used to treat polymicrobial infections, these agents have recently started to be incorporated on titanium surface. This review discusses the biofilm formation on titanium dental implants and key factors to be considered in therapeutic and preventative strategies. Moreover, a systematic review was conducted on coatings developed for titanium surfaces using different antibiotics. This review will also shed light on potential alternative strategies aiming to reduce microbial loads and control polymicrobial infection on implanted devices.

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

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.

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.

Effect of daily use of an enzymatic denture cleanser on Candida albicans biofilms formed on polyamide and poly(methyl methacrylate) resins: an in vitro study.

STATEMENT OF PROBLEM: Candida biofilms on denture surfaces are substantially reduced after a single immersion in denture cleanser. However, whether this effect is maintained when dentures are immersed in cleanser daily is unclear. PURPOSE: The purpose of this study was to evaluate the effect of the daily use of enzymatic cleanser on Candida albicans biofilms on denture base materials. MATERIAL AND METHODS: The surfaces of polyamide and poly(methyl methacrylate) resin specimens (n=54) were standardized and divided into 12 groups (n=9 per group), according to study factors (material type, treatment type, and periods of treatment). Candida albicans biofilms were allowed to form over 72 hours, after which the specimens were treated with enzymatic cleanser once daily for 1, 4, or 7 days. Thereafter, residual biofilm was ultrasonically removed and analyzed for viable cells (colony forming units/mm(2)) and enzymatic activity (phospholipase, aspartyl-protease, and hemolysin). Factors that interfered with the response variables were analyzed by 3-way ANOVA with the Holm-Sidak multiple comparison method (α=.05). RESULTS: Polyamide resin presented more viable cells of Candida albicans (P<.001) for both the evaluated treatment types and periods. Although enzymatic cleansing significantly (P<.001) reduced viable cells, daily use did not maintain this reduction (P<.001). Phospholipase activity significantly increased with time (P<.001) for both materials and treatments. However, poly(methyl methacrylate) based resin (P<.001) and enzymatic cleansing treatment (P<.001) contributed to lower phospholipase activity. Aspartyl-protease and hemolysin activities were not influenced by study factors (P>.05). CONCLUSIONS: Although daily use of an enzymatic cleanser reduced the number of viable cells and phospholipase activity, this treatment was not effective against residual biofilm over time.

The effect of poly(methyl methacrylate) surface treatments on the adhesion of silicone-based resilient denture liners.

STATEMENT OF PROBLEM: Different surface treatment protocols of poly(methyl methacrylate) have been proposed to improve the adhesion of silicone-based resilient denture liners to poly(methyl methacrylate) surfaces. PURPOSE: The purpose of this study was to evaluate the effect of different poly(methyl methacrylate) surface treatments on the adhesion of silicone-based resilient denture liners. MATERIAL AND METHODS: Poly(methyl methacrylate) specimens were prepared and divided into 4 treatment groups: no treatment (control), methyl methacrylate for 180 seconds, acetone for 30 seconds, and ethyl acetate for 60 seconds. Poly(methyl methacrylate) disks (30.0 × 5.0 mm; n = 10) were evaluated regarding surface roughness and surface free energy. To evaluate tensile bond strength, the resilient material was applied between 2 treated poly(methyl methacrylate) bars (60.0 × 5.0 × 5.0 mm; n = 20 for each group) to form a 2-mm-thick layer. Data were analyzed by 1-way ANOVA and the Tukey honestly significant difference tests (α = .05). A Pearson correlation test verified the influence of surface properties on tensile bond strength. Failure type was assessed, and the poly(methyl methacrylate) surface treatment modifications were visualized with scanning electron microscopy. RESULTS: The surface roughness was increased (P < .05) by methyl methacrylate treatment. For the acetone and ethyl acetate groups, the surface free energy decreased (P < .05). The tensile bond strength was higher for the methyl methacrylate and ethyl acetate groups (P < .05). No correlation was found regarding surface properties and tensile bond strength. Specimens treated with acetone and methyl methacrylate presented a cleaner surface, whereas the ethyl acetate treatment produced a porous topography. CONCLUSION: The methyl methacrylate and ethyl acetate surface treatment protocols improved the adhesion of a silicone-based resilient denture liner to poly(methyl methacrylate).

A three-species biofilm model for the evaluation of enamel and dentin demineralization.

Although Streptococcus mutans biofilms have been useful for evaluating the cariogenic potential of dietary carbohydrates and the effects of fluoride on dental demineralization, a more appropriate biofilm should be developed to demonstrate the influence of other oral bacteria on cariogenic biofilms. This study describes the development and validation of a three-species biofilm model comprising Streptococcus mutans, Actinomyces naeslundii, and Streptococcus gordonii for the evaluation of enamel and dentin demineralization after cariogenic challenges and fluoride exposure. Single- or three-species biofilms were developed on dental substrata for 96 h, and biofilms were exposed to feast and famine episodes. The three-species biofilm model produced a large biomass, mostly comprising S. mutans (41%) and S. gordonii (44%), and produced significant demineralization in the dental substrata, although enamel demineralization was decreased by fluoride treatment. The findings indicate that the three-species biofilm model may be useful for evaluating the cariogenic potential of dietary carbohydrates other than sucrose and determining the effects of fluoride on dental substrata.

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©).