PURPOSE. To evaluate the adherence to therapy by patients classified as being at high risk of caries.

MATERIALS AND METHODS. A randomized factorial trial with one-month follow-up was conducted. Adult patients at high risk of caries were recruited from a private dental practice. They were randomized according to a factorial trial design to use one or more of the following: fluoride mouthwash, chlorhexidine mouthwash, fluoride gel, and/or xylitol chewing-gum. At baseline, each patient was asked to score their oral health from 1 to 10. One month later, patients were contacted by telephone by another operator for interview regarding their use of the prescribed products, and once again to rate their oral health from 1 to 10. Asymmetric discordance and agreement between assigned therapy and therapy undertaken were performed respectively using the McNemar test and K-statistic.

RESULTS. Twenty-three patients were randomized, but there were three drop-outs. Only 11 of the remaining 20 participants (55%) adhered to the assigned therapy, while nine patients (45%) did not (95%CI from 23 to 68%). Six patients (30%) took at least one of the four therapies not prescribed them. Considering abstention from non-prescribed treatments, therefore, only 6 patients (30%; 95%CI from 12 to 54%) fully adhered to the therapy prescribed. Thus, 14 out of the 20 participants failed to fully adhere to the therapy prescribed (70%; 95% CI from 46 to 88%). Asymmetric discordance was significant for chlorhexidine mouthwash (four out of nine patients did not use the mouthwash, P = 0.0455) and for fluoride gel (five out of 11 patients did not use the gel, P = 0.0253), while it was non-significant for xylitol chewing-gum (P = 0.3173) and fluoride mouthwash (P = 1.0). Agreement was moderate for chlorhexidine mouthwash (K = 0.58), fluoride gel (K = 0.52), and xylitol chewing-gum (K = 0.60), and fair for fluoride mouthwash (K = 0.40). Patient satisfaction with therapy was 7.7 ± 2.4, but was not linked to any of the four treatments assigned: fluoride mouthwash (P = 0.7699), chlorhexidine (P = 0.8980), xylitol (P = 0.6203), fluoride gel (P = 0.3885). An increase in satisfaction with oral hygiene was observed (P = 0.0003), but was not associated with the treatment prescribed.

CONCLUSIONS. Adherence to therapy was rather low. After one month, many patients (about 45%) were not adhering to the prescribed therapy. Some treatments appear to have stimulated greater adherence than others.

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