Salivary and Caries - a Systematic Review

Objective: To appraise existing evidence in regard to an inversed relationship between saliva flow and dental caries. Materials and Methods: 9 anglo and 2 lusophone electronic databases were searched using English and Portuguese key words (22 March 2006). Relevant articles in English, German, Portuguese and Spanish were included for review. Trials were excluded on basis of lack of control group, if study and control group were not similar, lack of clear dosage-response relationship, in-vitro study design, if exposure did not precede outcome and compared groups were not measured the same way. Reviews were excluded if no clear exclusion and/or inclusion criteria were stated, if there was no information on clear search strategy, key words and databases used or if study-by-study critique tables were missing. Two reviewers independently extracted information, including unstimulated and stimulated whole saliva flow. A quality assessment of all accepted articles was carried out and the data obtained was considered as strong, good or reasonable evidence. Results: A total of 2373 articles were identified of which 85 articles were judged to be relevant to the topic. Of these, 27 reviews and 20 trials were subsequently excluded according to the exclusion criteria. 24 articles did not demonstrate an inversed relationship between caries experience and saliva flow rates. However these articles investigated flow rates within healthy limits; did not corrected confounder influences such as age and methods of saliva collection; or did not provide information on flow rate values. 14 articles of good quality did confirm a direct association between dental caries and low saliva secretion, considering as cut-off rates for unstimulated whole saliva flow <0.5 mL/min and stimulated whole saliva flow <1.0 mL/min. Conclusion: There is evidence that low saliva flow rate is inversed related to dental caries. Support: GC Asia and Midentistry.com