RESUMO
STATEMENT OF PROBLEM: Clinical evidence on the best chemical protocol for the disinfection and removal of biofilm from complete dentures is lacking. PURPOSE: The purpose of this crossover randomized clinical trial was to assess the effectiveness of various chemical hygiene clinical protocols in reducing the microbial viability of biofilm formed on complete dentures. MATERIAL AND METHODS: In this triple-blind (participants, dentist, and outcome evaluator) study, complete denture wearers without candidiasis were randomly divided into 4 groups (n=40) according to the chemical hygiene protocol: water (placebo), 0.5% sodium hypochlorite solution, 0.12% chlorhexidine gluconate solution, and 5% sodium bicarbonate solution. The biofilm formed on the palate intaglio and denture teeth was collected and assessed in each experimental phase for quantitative microbial viability at the seventh and 14th day after using the chemical protocol. RESULTS: Two participants were lost. Data were analyzed by MANOVA and Tukey HSD tests. Soaking dentures was not effective in decreasing Candida albicans, C. non-albicans, and lactobacillus counts. The use of sodium hypochlorite and chlorhexidine decreased total microorganisms and Streptococcus mutans counts for both palate and teeth compared with water and sodium bicarbonate. The intaglio of the dentures always presented higher microbial counts than did the denture teeth. CONCLUSIONS: The use of sodium hypochlorite and chlorhexidine and mechanical cleansing with a toothbrush decreased microbial viability in healthy complete denture wearers.
Assuntos
Prótese Total , Desinfecção/métodos , Desinfecção/normas , Higiene/normas , Idoso , Biofilmes/efeitos dos fármacos , Candida/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Clorexidina/análogos & derivados , Clorexidina/farmacologia , Estudos Cross-Over , Prótese Total/microbiologia , Feminino , Humanos , Lactobacillus/efeitos dos fármacos , Masculino , Viabilidade Microbiana/efeitos dos fármacos , Pessoa de Meia-Idade , Bicarbonato de Sódio/farmacologia , Hipoclorito de Sódio/farmacologia , Streptococcus mutans/efeitos dos fármacos , Escovação DentáriaRESUMO
This in vitro study investigated the development of dentin wall lesions next to resin composite containing very small gap sizes using an in vitro biofilm model, and evaluated whether a relevant threshold for the gap size could be established. Microcosm biofilms were grown for 14 days within small interfacial gaps between dentin-resin composite discs under intermittent cariogenic challenge. The factor under study was gap size: samples were either restored with composite resin without adhesive procedure (no intentional gap; no bonding [NB] group) or with intentional gaps of 30, 60, or 90 µm, or with complete adhesive procedure (no gap; bonding [B] group). Secondary caries wall lesion progression was measured in lesion depth (LD) and mineral loss (ML) using transversal wavelength independent microradiography at 3 locations: outer surface lesion and wall lesions at 200 and 500 µm distance from gap entrance. Results from linear regression analysis showed that the presence of an intentional gap (30, 60, and 90 µm) affected the secondary caries progression at 200 µm from the gap entrance (p ≤ 0.013). The NB group did not show significant wall lesion development (ML and LD, p ≥ 0.529). At 500 µm distance almost no wall caries development was observed. In conclusion, dentin wall lesions developed in minimal gap sizes, and the threshold for secondary wall lesion development was a gap of around 30 µm in this microcosm biofilm model.
Assuntos
Resinas Acrílicas/farmacologia , Biofilmes , Resinas Compostas/farmacologia , Cárie Dentária/patologia , Restauração Dentária Permanente , Adesivos Dentinários/farmacologia , Dentina/patologia , Poliuretanos/farmacologia , Saliva/microbiologia , Condicionamento Ácido do Dente , Animais , Bovinos , Cárie Dentária/diagnóstico por imagem , Dentina/diagnóstico por imagem , Humanos , Técnicas In Vitro , Teste de Materiais , Microrradiografia , Propriedades de SuperfícieRESUMO
This study investigated the cariogenic potential of biofilms originating from different types of inoculum (saliva and dental plaque) from caries-active and caries-free individuals. Ten volunteers were selected from each caries condition for the paired collection of saliva and dental plaque. Microcosm biofilms were grown in triplicate from each inoculum on enamel specimens in 24-well plates under cariogenic challenge. After 10 days, the biofilms were collected for analysis of outcome variables: percentage of surface hardness change (%SHC) and microbiological composition of biofilms. Statistical analysis was performed using the t test, the linear multivariate analysis model and Pearson's correlation coefficients (α = 0.05). A comparative analysis between microbiological baseline data showed higher counts of mutans streptococci in plaque samples within caries-active individuals; a comparative analysis of colony-forming unit (CFU) counts between individuals with different caries status showed higher counts of acid-tolerant microorganisms and mutans streptococci in dental plaque and of acid-tolerant microorganisms in saliva. After 10 days of biofilm growth, the CFU values for total microorganisms, lactobacilli, mutans streptococci and acid-tolerant bacteria, as well as for SHC, were not statistically significant, considering the type of inoculum and caries condition (p > 0.05). A positive correlation was found for %SHC and CFU counts of acid-tolerant bacteria (r = 0.406) and lactobacilli (r = 0.379). Under the limits of this study, the cariogenic potential of biofilms, formed under identical conditions in vitro, is similar, regardless of baseline differences between the source and type of inoculum.
Assuntos
Biofilmes/crescimento & desenvolvimento , Cárie Dentária/microbiologia , Esmalte Dentário/microbiologia , Placa Dentária/microbiologia , Saliva/microbiologia , Adolescente , Criança , Contagem de Colônia Microbiana , Dureza , Humanos , Lactobacillus/crescimento & desenvolvimento , Streptococcus mutans/crescimento & desenvolvimento , Streptococcus mutans/isolamento & purificação , Sacarose/metabolismo , Sacarose/farmacologia , Desmineralização do Dente/microbiologiaRESUMO
OBJECTIVES: This study was designed to adapt a previously developed in vitro microcosm biofilm model to create carries-affected dentin (CAD) and establish conditions for using the model in bonding studies. MATERIALS AND METHODS: Biofilms were originated from human saliva and grown on dentin discs for 0 (sound dentin), 3, 5, 7, 14, or 21 days under intermittent cariogenic condition (n = 10). At each time point, composite cylinders were bonded to the dentin using self-etch adhesive (Clearfil SE Bond). The response variables were integrated mineral loss (ΔS), lesion depth (LD), shear bond strength (SBS), and failure mode. Data were statistically analyzed (α = 0.05). Bonded interfaces were analyzed by scanning electron microscopy (SEM), and dentin surfaces characterized by infrared spectroscopy (Fourier transform infrared spectroscopy, FTIR). RESULTS: Lower ΔS was found for sound dentin than for CAD in all experimental groups, except for the group under cariogenic challenge for 3 days. The SBS to CAD was significantly lower than control for all cariogenic challenge times. Adhesive failures were predominant in all groups. ΔS and LD had a significant negative correlation with SBS. A significant exponential decay in SBS was associated with increased ΔS values. CAD had lower mineral and amide I content and an irregular hybridization interface compared to sound dentin. CONCLUSIONS: The microcosm biofilm model was able to artificially induce CAD, which imposed challenge to the bonding of the polymeric adhesive material. CLINICAL RELEVANCE: Presence of CAD might interfere with the bonding of polymeric materials. The microcosm biofilm model proposed could be useful for preclinical dentin bonding studies.