Ahmed Elkhadem

DATA SOURCES: Medline/PubMed, SCOPUS and Google Scholar.

DATA EXTRACTION AND SYNTHESIS: Studies were split according to the type of teeth and the overjet threshold used, thus obtaining three subsets; primary teeth - overjet threshold 3-4 mm; permanent teeth - overjet threshold 3-4 mm and permanent teeth - overjet threshold 6 ± 1 mm. Pooled odds ratios for TDI were estimated for each dataset.

RESULTS: Fifty-four studies were included involving patients from five continents. The adjusted pooled odds ratios were 2.31 (95%CI; 1.01-5.27) for primary teeth with 3-4 mm overjet; 2.01 (95%CI; 1.39-2.91) for permanent teeth with 3-4 mm overjet and 2.24 (95%CI; 1.56-3.21) for permanent teeth with 6 ± 1 mm overjet.

CONCLUSIONS: The present meta-analysis of observational studies showed that large overjet may double or even triple the risk for TDI to anterior primary and permanent teeth and that, at global level, large overjet is partly responsible for 100-300 million TDIs.

DATA SOURCES: CENTRAL, Medline, Embase, Web of Science, LILACS and BBO databases, the Brazilian database of thesis and dissertations (Banco de Teses CAPES), a Brazilian register of ethically approved projects involving human beings (SISNEP) and two registers of ongoing trials (Current Controlled Trials and Clinical-Trials.gov). Reference lists were also scanned for relevant papers. Study authors were contacted for additional information.

STUDY SELECTION: Individual or cluster-randomised or quasi-randomised controlled trials conducted in children under seven were included.

DATA EXTRACTION AND SYNTHESIS: Study selection and data abstraction were conducted by two reviewers independently. Risk of bias assessment was undertaken using the Cochrane Collaboration tool. Meta-analyses of prevented fractions (PF) were performed to assess the effect of fluoride toothpaste on the dmft and dmfs. Meta-analyses were also performed to obtain a pooled relative risk (RR) to assess the effect of fluoride toothpastes on the proportion of children developing caries.

RESULTS: Eight studies were included. When standard F toothpastes were compared to placebo or no intervention, significant caries reduction at surface (PF = 31%; 95% CI 18-43; 2644 participants in five studies), tooth (PF = 16%; 95% CI 8-25; 2555 participants in one study) and individual (RR = 0.86; 95% CI 0.81-0.93; 2806 participants in two studies) level were observed. Low F toothpastes were effective only at surface level (PF = 40%; 95% CI 5-75; 561 participants in two studies).

CONCLUSIONS: Standard F toothpastes are effective in reducing dental caries in the primary teeth of preschool children and thus their use should be recommended to this age group.

Seven distinct glycosidases (EC 3.2) have been characterized in guinea-pig epidermis. Their properties indicate them to be of lysosomal origin. The 'profile' of the epidermal glycosidases is significantly different from that reported for whole skin, the activities of beta-galactosidase and beta-acetylglucosaminidase being very high and those of the remaining enzymes relatively low in epidermis.