Effect of professional flossing with chlorhexidine or fluoride gel on approximal caries in children

Abstract

Dental caries on approximal tooth surfaces is still a problem in Sweden, as in many other industrialised countries. The aim of this thesis was therefore to evaluate a caries-preventive programme where professional flossing with 1% chlorhexidine, 1% NaF or 1% SnF2 gel was carried out 4 times a year. 0.7-1 ml gel was used on each occasion and a flat, waxed dental floss was moved back and forth 20 times in each approximal space. The treatment time was estimated to 10 min.The flossing method with chlorhexidine gel was evaluated both in 12-15-year olds (Paper I) and in 4-6-year-olds (Paper II). In another study (Paper IV), the professional flossing was combined with NaF or SnF2 gel in 13-16-year old children. All these three clinical studies were carried out during 3 years. Finally, the suppressive effect of the flossing method on mutans streptococci in saliva and dental plaque was compared with that of other modes of chlorhexidine gel application (Paper III). The caries reduction with the flossing method was similar, 30-43%, in Papers I, II and IV. The proportion of individuals not developing any new approximal caries lesions was 40-49% with the chlorhexidine/fluoride gels and 29-32% with placebo gels. A supplementary study to Paper IV showed that flossing with the two fluoride gels had a caries-reducing effect in children with low to moderate caries risk, but no or only a limited effect in children with high caries risk. As a supplementary study to Paper I, the teenagers were examined during 4 consecutive years after the end of the preventive treatment with chlorhexidine gel. The caries incidence was almost the same in the three original groups during the follow-up period and the differences achieved during the 3-year treatment period thus remained up to 19 years of age. In Paper II, the treatment time with the dental team (dentist and dental nurse) and the time for the prophylactic measures were registered. The difference in costs between a child following the flossing programme and a child in the control group was small, the flossing programme being slightly cheaper. The results from Paper III showed a transient reduction of colonisation of mutans streptococci by the flossing method. More pronounced suppression of these microorganism was achieved by combining interdental flossing with polishing the buccal, occlusal and lingual tooth surfaces. The main conclusions from this thesis are therefore: 1) that professional flossing with 1% chlorhexidine gel had a caries-reducing effect on approximal caries both in the permanent and in the primary dentition with around 40%, 2) that professional flossing with 1% NaF or 1% SnF2 gel in the permanent dentition had nearly the same caries-reducing effect as the chlorhexidine gel, and 3) that professional flossing with 1% chlorhexidine gel reduced the mutans streptococci population on various tooth surfaces during a comparative short period of time.