2. Effects of intervention: Caries in permanent dentition.
| Study ID | Intervention(s) and comparator | Outcome | Summary intervention | Summary comparator | Comment |
| Baca 200X | Cervitec (1% chlorhexidine, 1% thymol) varnish applied 4 x year (n = 86) No treatment (n = 95) |
Mean DFT increment (24 months) Mean DFS increment (24 months) |
Varnish 0.88 (SD 1.25) Varnish 0.95 (SD 1.38) |
No treatment 1.30 (SD 1.50) No treatment 1.85 (SD 2.27) |
Authors report "There was a significant difference in the increase in caries on surfaces at 24 months between the two groups.... However, when we consider the teeth (DFT index), although the increment was smaller in the varnish group (0.88) versus controls (1.30), the difference did not reach statistical significance." Statistical analysis did not take into account the cluster randomisation by school class. Inflation of the standard error of the effect estimate through a design effect with ICCs of 0.05, 0.1 and 0.2 resulted in a non‐statistically significant result for both outcomes. ICC 0 MD ‐0.42 (95% CI ‐0.82 to ‐0.02) ICC 0.05 MD ‐0.42 (95% CI ‐1.17 to 0.33) ICC 0.1 MD ‐0.42 (95% CI ‐1.51 to 0.67) ICC 0.2 MD ‐0.42 (95% CI ‐2.20 to 1.36) ICC 0 MD ‐0.9 (95% CI ‐1.45 to ‐0.35) ICC 0.05 MD ‐0.9 (95% CI ‐1.92 to 0.12) ICC 0.1 MD ‐0.9 (95% CI ‐2.40 to 0.60) ICC 0.2 MD ‐0.9 (95% CI ‐3.34 to 2.18) |
| Nordling 1999 | Cervitec (1% chlorhexidine, 1% thymol) varnish applied 3 x year (n = 271) Plain varnish (n = 271) | Mean DFS increment (24 months) | Varnish 1.8 (no SD reported) | Placebo 1.9 (no SD reported) | No re‐analysis possible due to incomplete reporting |
| Bretz 1997 | Chlorzoin 10% chlorhexidine applied after 3 months (n = 43) No treatment (n = 40) |
Mean % of sound surfaces (6 months) | Varnish 114.3 (SD 12.4) | No treatment 116.3 (SD 11.8) | Caries data presented as " dental decay parameters" i.e. % of sound, decayed, restored surfaces only. The trial reported that for all participants "...treatment groups were not predictors of dental decay parameters after 6 months" and for those participants treated as instructed at baseline examination "No significant differences on dental decay parameters were found between T and C groups at the 6 month examination". |
| Forgie 2000 | Chlorzoin 10% chlorhexidine applied 4 x year (n = 222) Placebo (n = 274) |
Mean DMFS increment (36 months) | Varnish 6.83 (SD 6.17) | Placebo 6.39 (SD 6.41) | Authors reported "...the clinical trial failed to reject the null hypothesis of no difference in caries‐reducing efficacy between active and placebo chlorhexidine varnishes." (MD 0.44, 95% CI ‐0.67 to 1.55) |
| De Soet 2002 | 40% chlorhexidine varnish (EC40®) applied 2 x year (n = 99) Placebo: neutral gel without chlorhexidine (n = 95) |
DMFS (30 months) | Varnish 6.16 (SD 10.01) | Placebo 5.25 (SD 6.03) | Authors reported "...no significant effect of CHX treatment on DMFS (p > 0.5)." (MD 0.91, 95% CI ‐1.40 to 3.22) |
CHX: chlorhexidine CI: confidence interval DFS: decayed and filled surfaces DFT: decayed and filled teeth DMFS: decayed, missing and filled surfaces ICC: intraclass correlation coefficient MD: mean difference SD: standard deviation