Marine collagen scaffolds and photobiomodulation on bone healing process in a model of calvaria defects.

INTRODUCTION: Collagen from marine esponges has been used as a promising material for tissue engineering proposals. Similarly, photobiomodulation (PBM) is able of modulating inflammatory processes after an injury, accelerating soft and hard tissue healing and stimulating neoangiogenesis. However, the effects of the associated treatments on bone tissue healing have not been studied yet. In this context, the present study aimed to evaluate the biological temporal modifications (using two experimental periods) of marine sponge collagen or sponging (SPG) based scaffold and PBM on newly formed bone using a calvaria bone defect model. MATERIAL AND METHODS: Wistar rats were distributed into two groups: SPG or SPG/PBM and euthanized into two different experimental periods (15 and 45 days post-surgery). A cranial critical bone defect was used to evaluate the effects of the treatments. Histology, histomorfometry and immunohistological analysis were performed. RESULTS: Histological findings demonstrated that SPG/PBM-treated animals, 45 days post-surgery, demonstrated a higher amount of connective and newly formed bone tissue at the region of the defect compared to CG. Notwithstanding, no difference among groups were observed in the histomorphometry. Interestingly, for both anti-transforming growth factor-beta (TGF-ß) and anti-vascular endothelial growth factor (VEGF) immunostaining, higher values for SPG/PBM, at 45 days post-surgery could be observed. CONCLUSION: It can be concluded that the associated treatment can be considered as a promising therapeutical intervention.

Oral health and obesity in the SAYCARE study: reliability and internal validity of diagnostic methods.

OBJECTIVE: The aim of this pilot study was to address the reliability, internal validity and viability of oral health methods used in the South American Youth/Child cARdiovascular and Environmental study. METHODS: South American Youth/Child cARdiovascular and Environmental study was a multicentre feasibility observational study and conducted in seven South American cities. The training sessions were performed in two steps before data collection: the first verified the inter-rater reproducibility between the examiners of the six centres in relation to the gold standard, and the second one verified the inter-rater reproducibility between the examiners at each centre in relation to the main rater. The diagnostic methods used were International Caries Detection and Assessment System II and Pulpal Involvement, Ulceration, Fistula and Abscess for dental caries and Periodontal Screening and Recording and Index Plaque for periodontal disease. Anthropometric variables were measured and used to calculate the body mass index and were classified according to the cut-off points defined by the International Obesity Task Force. Cohen's kappa coefficient and proportions of agreement were calculated to report inter-rater and intra-rater reliability in the calibration process and pilot study. RESULTS: The inter-rater weight kappa ranged from 0.78 to 0.88 and proportion of agreement from 96.07% to 98.10% for the International Caries Detection and Assessment System II and for the Periodontal Screening and Recording, 0.68 to 0.95 and 94.40% to 98.33%, respectively, in the calibration process. At the pilot study, a total of 490 children (40.8% overweight and 12.9% obese) and 364 adolescents (23.4% overweight and 4.3% obese) were examined. The prevalence of dental caries was 66% in children and 78% in adolescents, and gingival bleeding was 49% and 58.20%, respectively. CONCLUSION: The results demonstrated good reliability and internal validity after the examiners were trained, as well as the feasibility of using the methods chosen for this multicentre study.

Effect of High-Fluoride Dentifrice on Enamel Erosion Adjacent to Restorations In Vitro.

AIM: This in vitro study analyzed the antierosive potential of a high-fluoride dentifrice on enamel adjacent to restorations. METHODS AND MATERIALS: Enamel blocks (6 × 6 × 3 mm) from bovine incisor teeth were restored with three different restorative materials (resin, conventional glass ionomer cement, and resin-modified glass ionomer cement) and treated with dentifrices containing 0, 1100, or 5000 ppm F. After restorative procedures, initial surface Vickers hardness of the blocks were obtained. The specimens were submitted to pH cycles (4 × 90 seconds in soft drink) and treatments for five days. Between the challenges and overnight, the blocks remained in artificial saliva. At the end of the experiment, the final hardness was assessed and the percentage of surface mineral loss (%SML) was calculated. A 3 × 3 factorial design was used to conduct statistical analysis. Data were analyzed by analysis of variance and t-test, with significance level fixed at 5%. RESULTS: High-fluoride dentifrice decreased demineralization caused by erosive challenge regardless of the restorative material used (p<0.001). Likewise, the blocks restored with conventional glass ionomer cement showed lower values of SML irrespective of dentifrice used (p<0.001). CONCLUSION: Use of a high-fluoride dentifrice on teeth restored with conventional glass ionomer cement offers additional protection against enamel erosion.

APF and dentifrice effect on root dentin demineralization and biofilm.

Because dentin is more caries-susceptible than enamel, its demineralization may be more influenced by additional fluoride (F). We hypothesized that a combination of professional F, applied as acidulated phosphate F (APF), and use of 1100-ppm-F dentifrice would provide additional protection for dentin compared with 1100-ppm-F alone. Twelve adult volunteers wore palatal appliances containing root dentin slabs, which were subjected, during 4 experimental phases of 7 days each, to biofilm accumulation and sucrose exposure 8x/day. The volunteers were randomly assigned to the following treatments: placebo dentifrice (PD), 1100-ppm-F dentifrice (FD), APF + PD, and APF+FD. APF gel (1.23% F) was applied to the slabs once at the beginning of the experimental phase, and the dentifrices were used 3x/day. APF and FD increased F concentration in biofilm fluid and reduced root dentin demineralization, presenting an additive effect. Analysis of the data suggests that the combination of APF gel application and daily regular use of 1100-ppm-F dentifrice may provide additional protection against root caries compared with the dentifrice alone.

Temporal relationship between sucrose-associated changes in dental biofilm composition and enamel demineralization.

The aim of this study was to investigate the temporal relationship between changes in biofilm composition and enamel demineralization following exposure to sucrose. A crossover blind study was conducted in situ in three phases, during which 12 volunteers, divided into three groups, subjected enamel slabs 8 times/day to water (negative control), 10% glucose + 10% fructose (active control) or 20% sucrose solution. Biofilms accumulated for 3, 7 and 14 days were collected and analyzed biochemically and microbiologically, and mineral loss from enamel (deltaZ) was evaluated. Significantly higher deltaZ was found in the sucrose group after 7 days. However, on the 3rd day, lactobacilli, insoluble extracellular polysaccharide (EPS) and intracellular polysaccharide were significantly higher, and the calcium, inorganic phosphorus and fluoride concentrations in the biofilm were significantly lower in the sucrose group than in the negative controls. The only significant difference compared to glucose + fructose treatment was a higher insoluble EPS concentration. The data suggest that, although sucrose induces significant enamel demineralization only after 7 days of biofilm accumulation, changes in the biofilm composition are observed earlier.

Effect of frequency of sucrose exposure on dental biofilm composition and enamel demineralization in the presence of fluoride.

It has been suggested that enamel would resist higher frequencies of sucrose exposure if fluoride from water or dentifrice is being used. However, the effect of increasing frequencies of sugar on dental biofilm composition is not well known. Ten volunteers living in a fluoridated area wore palatal appliances bearing human enamel slabs during 14 days. The slabs were exposed to 20% sucrose solution 0 (control), 2, 4, 6, 8 or 10 times/day and the volunteers used fluoride dentifrice 3 times/day. Enamel demineralization was significantly greater than control for sucrose frequencies higher than 6 times/day. However, biofilm mass, total microbiota, total streptococci, lactobacilli counts and insoluble extracellular polysaccharide concentration increased, while Ca, P(i) and F concentration in whole biofilm decreased significantly, with frequencies of sucrose exposure lower than 6 times/day. The findings confirm that fluoride can reduce enamel demineralization if sucrose consumption is not higher than 6 times/day, but changes in the biochemical and microbiological composition of the biofilm are observed with lower frequencies of sucrose use.