RESUMO
AIM: The purpose of this study was to characterise the enamel surface of sound deciduous teeth in terms of morphology, chemical composition, structure and crystalline phases. MATERIALS AND METHODS: The enamel of 30 human deciduous teeth was examined by: Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), X-ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS). Chemical differences between incisors and canines were statistically evaluated using the Mann-Whitney U test (p ≤ 0.05). RESULTS: Three enamel patterns were observed by SEM: 'mostly smooth with some groves', 'abundant microporosities' and 'exposed prisms'. The average Ca/P molar ratios were 1.37 and 1.03 by EDS and XPS, respectively. The crystallite size determined by XRD was 210.82 ± 16.78 Å. The mean ratio between Ca bonded to phosphate and Ca bonded to hydroxyl was approximately 10:1. CONCLUSION: The enamel of sound deciduous teeth showed two main patterns: 'mostly smooth with some groves' and 'abundant microporosities'. 'Exposed prisms' was a secondary pattern. There were slight variations among the Ca/P molar ratios found by EDS and XPS, suggesting differences in the mineral content from the enamel surface to the interior. The crystalline phases found in enamel were hydroxyapatite and carbonate apatite, with major type B than type A carbonate incorporation.
Assuntos
Esmalte Dentário/ultraestrutura , Dente Decíduo/ultraestrutura , Apatitas/análise , Cálcio/análise , Cristalografia , Dente Canino/química , Dente Canino/ultraestrutura , Esmalte Dentário/química , Durapatita/análise , Humanos , Hidróxidos/análise , Incisivo/química , Incisivo/ultraestrutura , Microscopia Eletrônica de Varredura , Fosfatos/análise , Fósforo/análise , Espectroscopia Fotoeletrônica , Porosidade , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Dente Decíduo/química , Difração de Raios XRESUMO
OBJECTIVE: To identify the sociodemographic, socio-economic, clinical and behavioural factors that modify the experience of decayed, missing and filled teeth (DMFT) and caries prevalence in Nicaraguan children 9-12 years old. SUBJECTS AND METHODS: We conducted a cross-sectional study in 800 school children 9-12 years old in the city of León, Nicaragua. The clinical oral examinations to identify caries experience were undertaken by two trained and certified examiners. Sociodemographic, socio-economic and behavioural data were collected using questionnaires. Negative binomial regression (NBR) and binary logistic regression (BLR) models were used to model caries experience and caries prevalence, respectively. RESULTS: Mean DMFT index was 0.98 ± 1.74 and caries prevalence (DMFT > 0) was 37.9%. In the NBR model, the categories that increase the expected DMFT mean were: older age, female gender, presence of plaque, and if the school children received curative and curative/preventive dental care in the last year. In the BLR model, the odds of presenting with caries in the permanent dentition were increased in older children, those from large families, mothers with a positive dental attitude, and those school children who received curative and curative/preventive dental care in the last year. CONCLUSIONS: Using different models, we identified several sociodemographic, socio-economic, clinical and behavioural factors that modify the experience (NBR) and prevalence (BLR) of dental caries.
RESUMO
BACKGROUND: This investigation aimed to determine quantitatively the adhesion of Streptococcus mutans and Streptococcus sobrinus to orthodontic composite resins that were tested simultaneously using radio-markers. METHODS: Seven orthodontic composite resins were classified into seven groups: BeautyOrtho Bond (GI), Blugloo (GII), Enlight (GIII), Grengloo (GIV), Kurasper F (GV), Transbond CC (GVI) and Turbo Bond II (GVII). Thirty 4 x 4 x 1 mm blocks of each orthodontic composite resin were made (a total of 210 blocks). Both Streptococcus species were cultivated independently. For the quantitative analysis, radioactive markers were used to codify the bacteria ((3) H for Streptococcus mutans and (14) C for Streptococcus sobrinus). The blocks were submerged in a solution with microorganisms previously radiolabelled for 2 hours at 37 °C in constant movement. The blocks were placed in a combustion system to quantify the Streptococcus adhering to the surface of the materials by capturing the residues and measuring the radiation. RESULTS: Significant differences in bacterial adhesion were found among the groups. The lowest significant scores for both microorganisms were observed in GIII. CONCLUSIONS: The orthodontic composite resin evaluated in GIII exhibited the lowest adhesion of Streptococcus mutans and Streptococcus sobrinus, which may reduce enamel demineralization and the risk of white spot lesion formation.
Assuntos
Resinas Compostas , Streptococcus mutans/fisiologia , Streptococcus sobrinus/fisiologia , Resinas Acrílicas , Aderência Bacteriana , Bis-Fenol A-Glicidil Metacrilato , Esmalte Dentário , Ácidos Fosfóricos , Cimentos de Resina , Desmineralização do Dente/microbiologia , Desmineralização do Dente/prevenção & controleRESUMO
BACKGROUND: The aim of this study was to quantitatively determine the adherence of Streptococcus mutans to orthodontic band cements. METHODS: Two hundred and ten blocks of seven different band cements for orthodontic prescription were made using a Teflon mould (4 × 4 × 1 mm). The obtained blocks were slightly polished and cleansed ultrasonically. Certified S. mutans ATCC 25175 were cultured with conventional methods for growth in Petri dishes and trypticase soy broth. Quantitative analysis was carried out with radioactive markers to codify the bacteria ((3) H). Subsequently, a combustion system was used to capture the residues, the radioactivity of the samples was measured, and the values recorded in disintegrations per minute (dpm). One-way analysis of variance (ANOVA) with a Scheffé test for multiple comparisons was realized with a significance level of ≤0.05. RESULTS: Significant differences were found among different band cement materials (p < 0.001). Two band cement materials showed statistically lower values than the others (Transbond Plus Band Cem and Ketac Cem). In contrast, GC Fuji Ortho Band presented the highest adherence of S. mutans. CONCLUSIONS: Among the cements evaluated, Transbond Plus Band Cem and Ketac Cem showed lower adherence of S. mutans.