Reversal of root caries using fluoride toothpastes with or without bioactive glass - an in vitro study

To evaluate the effect of fluoridated toothpastes with or without bioactive glass on root caries.

A total of 94 extracted teeth with 128 root caries were assessed using visual-tactile assessments and light-induced fluorescence-evaluator (SoproLIFE) at baseline and after three months to determine the severity of lesions. Each lesion was randomly allocated into four groups: Group-1: Bioactive glass (BG) with 540 ppm fluoride, Group-2: 5,000 ppm fluoride, Group-3: 1,450 ppm fluoride, Group-4: Deionised water. Standardised tooth-brushing was performed twice a day. Samples were stored in remineralising solution (pH7) at 37°C. Raman spectroscopy and scanning electron microscopy (SEM) were conducted at three months.

There was a significant decrease in severity index of root caries in treatment groups (p=0.03). 44% of lesions in Group-2 reversed and became hard (SI0), whilst 41% in Group-1, 38% and 19% of root caries in Groups-3 and 4 respectively reversed to SI0. The SoproLIFE results demonstrated that 25% of lesions in BG with 540 ppm fluoride, 19% in 5,000 ppm fluoride, whilst 16% in 1,450 ppm fluoride, 28% in deionised water group became hard. 3% of lesions became worse in deionised water group only. Raman spectroscopy indicated that phosphate content was highest in 5,000 ppm fluoride, followed by BG with 540 ppm fluoride>1,450 ppm fluoride>deionised water groups. SEM analyses showed partially/completely closed dentinal tubules in all toothpaste groups, however, tubules were exposed in deionised water group.

Within the limitations of this study, all toothpastes were potentially effective in hardening root carious lesions and remineralisation. 5,000 ppm fluoride had a superior effect in promoting remineralisation.

All study toothpastes have potential benefits in arresting and reversing root caries. These findings can provide further evidence to support the development of updated guidelines for root caries.