Povidone iodine and NaF varnish versus SDF solution in dental root caries prevention

Abstract

Introduction: Silver diamine fluoride (SDF) has been found to be effective in preventing and arresting dental root caries. There is limited study on the alternative options in root caries management when SDF is not available. This is the first study on a combined use of an antiseptic and a topical fluoride in root caries management. Objectives: This study aimed to compare the effectiveness of SDF solution, and the combination of povidone iodine (PVP-I) solution and sodium fluoride (NaF) varnish in root caries prevention and arrest. Methods: The study participants were community-dwelling older adults in Hong Kong. Older adults who had at least 6 natural teeth and basic self-care ability were randomly allocated to one of the two study groups: Group 1 – annual application of 38% SDF solution; Group 2 – 4-monthly application of 10% PVP-I solution and 5% NaF varnish. Status of the exposed root surfaces was assessed annually for two years by the same calibrated examiners. Results: A total of 353 participants (mean age = 74.9) with 12,972 exposed root surfaces were included at baseline. Among them, 290 (82.2%) were examined at the 24-month follow-up. The mean numbers of root surfaces with new caries experience in Group 1 and Group 2 were 1.3 and 1.2, respectively (t-test, p>0.05). Participants with a higher proportion of root surfaces with visible plaque (IRR=15.0, p<0.001) and with higher baseline DMFT score (IRR=1.06, p=0.001) had more new root caries. Results of multi-level logistic regression analysis show that older participants (OR=1.03, p=0.004) and surfaces with plaque at the 24-month follow-up (OR=12.4, p<0.001) had higher root caries risk. Lower anterior teeth were less likely to develop new root caries (OR=0.41, p<0.001). Lower frequency of tooth brushing, higher baseline DMFT score, fewer exposed root surfaces, presence of plaque on root surfaces and gingival bleeding at baseline were associated with a faster rate of new caries development. Among the 353 participants, 98 of them had 206 active root caries lesions at baseline. After 24 months, 76 (77.6%) participants and 134 (65.0%) lesions were evaluated. The proportions of root caries lesions that were arrested at the 24-month examination in Group 1 and Group 2 were 99% and 68%, respectively (Fisher’s exact test, p<0.001). In the final multi-level logistic regression model, active root caries lesions in the SDF group (OR=35.3, p=0.001) had a higher chance while those with visible plaque present at baseline (OR=0.20, p=0.017) and 24-month follow-up (OR=0.23, p=0.048) had a lower chance to become arrested. The shallower lesions and those in Group 1 became arrested faster than the deeper lesions and those in Group 2. Conclusions: Topical application of 10% PVP-I solution and 5% NaF varnish every four months is not inferior to annual topical application of 38% SDF solution in preventing dental root caries among community-dwelling older adults. Annual topical application of 38% SDF solution is more effective and efficient than 4-monthly topical application of 10% PVP-I solution and 5% NaF varnish in arresting active root surface caries.