A randomized clinical trial on preventing and arresting dental root caries using silver diammine fluoride solution in community-dwelling elders

Abstract

Introduction: Silver diammine fluoride (SDF) has been found to be effective in preventing and in arresting dental caries in primary teeth. Clinical evidence to support its use for managing dental root caries in elders is limited. Besides, no clinical study has been conducted to reduce the staining caused by SDF on the arrested caries lesions.

Objectives: This study aimed to investigate the effectiveness of SDF in preventing and in arresting dental root caries in elders and to assess the effects of applying potassium iodide (KI) after SDF application on the color of arrested root caries lesions.

Methods: This study was conducted among community-dwelling elders in Hong Kong. Elders who had at least 5 teeth with exposed root surfaces were randomly allocated into three intervention groups as follows: Group 1 – received oral hygiene instruction (OHI) and soda water (placebo control); Group 2 – received OHI and annual application of SDF solution; and Group 3 – received OHI and annual application of SDF solution followed immediately by KI solution. Status of the dental root surfaces was assessed clinically every 6 months by the same independent examiner. Color of the arrested root caries lesion was assessed using PANTONE color sheets.

Results: A total of 323 elders (mean age=72.1) with 13499 sound exposed root surfaces were examined at baseline. Among them, 257 (79.6%) were followed for 30 months. The mean numbers of dental root surface with new caries found at the 30-month examination in Groups 1, 2, and 3 were 1.1, 0.4, and 0.6 respectively (ANOVA, p<0.05). Elders who had higher 30-month VPI score and higher baseline DFMT score developed more new caries (ANCOVA, p<0.05). Results of a multi-level logistic analysis showed that applications of either SDF or SDF/KI were effective in preventing new root caries.

Among the 323 elders, 83 elders with 157 root surfaces with active caries lesion were found at baseline. After 30 months, 67 (80.7%) elders with 100 (63.7%) root caries lesions were reviewed. The arrest rates of root caries at the 30-month examination were 45%, 90%, and 93% in Groups 1, 2, and 3, respectively (χ^2 test, P<0.001). Results of a multi-level survival analysis showed that the arrest time of root caries lesions in the SDF group and the SDF/KI group was significantly shorter than that of the lesions in the control group.

In addition, the distributions of arrested carious lesions by color were not significantly different between the SDF and SDF/KI groups (Fisher’s exact test, P>0.05).

Conclusions: Annual topical application of either SDF solution or SDF/KI solution is effective in preventing and in arresting dental root caries among community-dwelling elders. The application of KI solution does not affect the effectiveness of SDF solution and also does not reduce the black staining caused by SDF solution.