Role of Fluoridated Dentifrices in In Vitro Root Caries Formation

Objective: In vitro root caries formation in permanent teeth was evaluated to determine effects of commercially available fluoridated dentifrices.

Method: Root surfaces from caries-free permanent teeth (n=10) underwent debridement and fluoride-free prophylaxis. Tooth roots were sectioned into 5 portions, and acid-resistant varnish was placed with 2 sound root surface windows exposed on each portion. Each portion from single tooth was assigned to treatment group: 1) No treatment control; 2)  Denticious 5000 dentifrice (5,000ppm Fl, Research Based Professional Products, Aventura FL 33180); 3) AIM dentifrice (1500ppm FL, Church & Dwight, Princeton NJ 08543); 4) Listerine dentifrice (1300ppm FL, Johnson & Johnson, Skillman NJ08558); and 5) Crest Regular Paste (1500ppm FL, Proctor & Gamble, Cincinnati OH 45202). Tooth portions were treated with fresh dentifrice twice daily for 180s followed by fresh synthetic saliva rinsing over 7d period. Controls exposed twice daily to fresh synthetic saliva rinsing over 7d period. In vitro root caries were created using acidified gel (pH 4.25, 21d). Longitudinal sections (3/tooth portion, 60/group) were evaluated for mean lesion depths (water imbibition, polarized light, ANOVA, DMR).

Result: Mean lesion depths were 389±43µm for No Treatment Control; 223±33µm for Denticious 5000 dentifrice; 337±29µm for AIM dentifrice; 297±37µm for Listerine Dentifrice; and 282±34µm for Crest Regular Paste Dentifrice. All treatment groups had mean depths significantly less than No Treatment Control group (P<.05). Denticious 5000 had significantly reduced mean depth compared with other dentifrice treatment groups (P<.05).

Conclusion: Fluoride-containing dentifrices provided significant reductions in mean lesion depths in root surfaces compared with control root surface not exposed to dentifrice treatment. A dentifrice that contains 5,000ppm fluoride (Denticious 5000) provided a greater degree of caries protection for root surfaces compared with dentifrices that contain 1300 to 1500ppm fluoride. Dentifrices with higher fluoride content may be important in prevention of caries in exposed root surfaces.