Association between dental hygiene, gingivitis and overweight or the risk of overweight in primary teeth of 4- and 5-year-old preschoolers in México.

OBJECTIVE: To determine the association between dental hygiene, gingivitis and overweight or the risk of overweight according to body mass index (BMI). METHODS: A cross-sectional study was performed with 1527 preschoolers. The children were divided into 4 groups: (i) absence of visible plaque and normal weight; (ii) absence of visible plaque and risk of overweight or overweight; (iii) presence of visible plaque and normal weight; and (iv) presence of visible plaque and risk of overweight or overweight. The clinical parameters evaluated were as follows: body mass index, degree of urban marginalization, dental caries, the simplified oral hygiene index and gingival status. Bivariate analysis and multivariate binary logistic regression models were used to identify associations between variables. RESULTS: The highest mean of gingivitis (0.28) was observed in the groups with visible plaque with normal weight and with overweight and risk of overweight. The presence of visible plaque and risk of overweight or overweight were positively associated (P = .0001) with the mean of gingivitis (OR = 8.28, 95% CI = 3.30-19.8). The absence of visible plaque and risk of overweight or overweight (P = .0001) were also positively associated with the presence of gingivitis (OR = 2.44, 95% CI = 0.68-8.06). This is after both models were adjusted by gender and degree of marginalization. CONCLUSIONS: The professionals should develop interdisciplinary approaches to (i) propose appropriate interventions to improve oral health in overweight preschoolers; and (ii) propose interventions to decrease the overweight with the possibility of also reducing its association with gingivitis.

Molecular identification and antibiotic resistant bacteria isolated from primary dentition infections.

BACKGROUND: Bacterial resistance to antibiotics is a health problem in many parts of the world. The aim of this study was to identify bacteria from dental infections and determine bacterial resistance to antibiotics used in dental care in the primary dentition. METHODS: This cross-sectional study comprised 60 children who presented for dental treatment for active dental infections in the primary dentition. Samples from dental infections were collected and bacteria were identified by polymerase chain reaction (PCR) assay. Bacterial resistance to antibiotics was determined by colony forming units on agar plates containing amoxicillin, clindamycin and amoxillicin-clavulanic acid (A-CA) tested at 8 µg/ml or 16 µg/ml. RESULTS: Clindamycin in both concentrations tested (8 µg/ml and 16 µg/ml) showed the highest bacterial resistance (85.9%), followed by amoxicillin (43.7%) and A-CA (12.0%). All comparisons among the three antibiotics used in the study exhibited statistical significance (p = <0.05) in both concentrations tested (8 µg/ml and 16 µg/ml), and under aerobic and anaerobic conditions. The most prevalent resistant species identified by PCR in primary dentition infections were: Streptococcus oralis and Prevotella intermedia (75.0%); Treponema denticola and Porphyromonas gingivalis (48.3%); Streptococcus mutans (45.0%); Campylobacter rectus; and Streptococcus salivarius (40%). CONCLUSIONS: This study demonstrated that A-CA exhibited the lowest bacterial resistance for clinical isolates in primary dentition infections.

Adherence inhibition of Streptococcus mutans on dental enamel surface using silver nanoparticles.

The aim of this ex vivo study was to evaluate the adherence capacity of Streptococcus mutans after being exposed to three different sizes of silver nanoparticles on healthy human dental enamel. Three different sizes of silver nanoparticles (9.3, 21.3 and 98 nm) were prepared, characterized and an adherence testing was performed to evaluate their anti-adherence activity on a reference strain of S. mutans on healthy dental enamel surfaces. Colony-Forming Unit count was made for adherence test and light microscopy, atomic force microscopy and scanning electron microscopy were used to compare qualitative characteristics of S. mutans. 9.3 nm and 21.3 nm groups did not show differences between them but statistical differences were found when 9.3 nm and 21.3 nm groups were compared with 98 nm and negative control groups (p<0.05). Microscopy analysis shows a better inhibition of S. mutans adherence in 9.3 nm and 21.3 nm groups than the 98 nm group when compared with control group. Silver nanoparticles showed an adherence inhibition on S. mutans and the anti-adherence capacity was better when silver nanoparticles were smaller.

Enamel roughness and depth profile after phosphoric acid etching of healthy and fluorotic enamel.

BACKGROUND: Dental fluorosis requires aesthetic treatment to improve appearance and etching of enamel surfaces with phosphoric acid is a key step for adhesive restorations. The aim of this study was to evaluate surface roughness and a depth profile in healthy and fluorotic enamel before and after phosphoric acid etching at 15, 30 and 60 seconds. METHODS: One hundred and sixty enamel samples from third molars with no fluorosis to severe fluorosis were evaluated by atomic force microscopy. RESULTS: Healthy enamel showed a statistically significant difference (p < 0.05) between mean surface roughness at 15 seconds (180.3 nm), 30 seconds (260.9 nm) and 60 seconds (346.5 nm); depth profiles revealed a significant difference for the 60 second treatment (4240.2 nm). For mild fluorosis, there was a statistically significant difference (p < 0.05) between mean surface roughness for 30 second (307.8 nm) and 60 second (346.6 nm) treatments; differences in depth profiles were statistically significant at 15 seconds (2546.7 nm), 30 seconds (3884.2 nm) and 60 seconds (3612.1 nm). For moderate fluorosis, a statistically significant difference (p < 0.05) was observed for surface roughness for 30 second (324.5 nm) and 60 second (396.6 nm) treatments. CONCLUSIONS: Surface roughness and depth profile analyses revealed that the best etching results were obtained at 15 seconds for the no fluorosis and mild fluorosis groups, and at 30 seconds for the moderate fluorosis group. Increasing the etching time for severe fluorosis decreased surface roughness and the depth profile, which suggests less micromechanical enamel retention for adhesive bonding applications.

Characterization of silver nanoparticles synthesized on titanium dioxide fine particles.

Silver nanoparticles with a narrow size distribution were synthesized over the surface of two different commercial TiO(2) particles using a simple aqueous reduction method. The reducing agent used was NaBH(4); different molar ratios TiO(2):Ag were also used. The nanocomposites thus prepared were characterized using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), dynamic light scattering (DLS) and UV-visible (UV-vis) absorption spectroscopy; the antibacterial activity was assessed using the standard microdilution method, determining the minimum inhibitory concentration (MIC) according to the National Committee for Clinical Laboratory Standards. From the microscopy studies (TEM and STEM) we observed that the silver nanoparticles are homogeneously distributed over the surface of TiO(2) particles and that the TiO(2):Ag molar ratio plays an important role. We used three different TiO(2)Ag molar ratios and the size of the silver nanoparticles is 10, 20 and 80 nm, respectively. It was found that the antibacterial activity of the nanocomposites increases considerably comparing with separated silver nanoparticles and TiO(2) particles.