Reactivity of aragonite with dicalcium phosphate facilitates removal of dental calculus

Abstract

Dental calculus, a main contributor of periodontal diseases, is mostly composed of inorganic calcium phosphate species such as dicalcium phosphate, whitlockite, octa calcium phosphate, and hydroxyapatite. Under physiological pH 7.4, dicalcium phosphates can gradually interact with calcium carbonate to form hydroxyapatite. Therefore, we hypothesized that aragonite (Arg) could react with dental calculus, facilitating its removal. To assess the reactivity of Arg with dental calculus, we examined the changes in surface morphology, composition, and topography of Arg and dental calculus upon exposure to each other in an aqueous environment. The impact of Arg on the removal of dental calculus was assessed by brushing polished sections of dental calculus, enamel, and dentin with slurries of Arg and measuring the depth of abrasion using a stylus profilometer. Our results demonstrate that Arg can react with dental calculus in aqueous environment. This reaction increases calculus surface roughness which in turn facilitate dental calculus removal by brushing. Aragonite could be a promising abrasive for toothpaste design for management of dental calculus.

This study proposes an innovative approach for the softening and removal of dental calculus based on the use of aragonite. This novel approach, which takes advantage of the chemical reactivity between aragonite and the minerals found in dental calculus, opens the door for developing homecare products that could help patients and clinicians more effectively control and manage dental calculus deposits. Anti-calculus Action. Pyrophosphate and carboxylate inhibit calculus formation by preventing calcium phosphate deposition in plaque.

Fig. 1

Anticalculus Action. Pyrophosphate and carboxylate inhibit calculus formation by inhibiting calcium phosphate deposition in plaque

Fig. 2

A, B Customized mechanical brushing system showing the mounted resin mold, (C) resin-embedded sections mounted in the Mach-1 instrument, (D) resin-embedded calculus sections, and (E) resin-embedded enamel/dentin sections

Fig. 3

Characterization of calcite, aragonite (Arg), treated aragonite (TArg) powder: A, B SEM micrographs, (C), (D) Higher magnification, (E) Specific surface area (p < 0.05), (F) Particle size (p < 0.05), (G) Particle size distribution, (H) TGA, (I) FTIR, and (J) XRD

Fig. 4

A FTIR spectra of TArg powder before and after 14 days of incubation in saturated CaP solution (*: ${\mathrm{PO}}_4^{3-}$ group), (B) Ca⁺² concentration in the supernatant, and (C) ${\mathrm{PO}}_4^{-3}$ concentration in the supernatant

Fig. 5

Characterization of TArg slurry before and after exposure to calculus, (A) XRD graphs, (B) crystallographic parameters, (C) EDX analysis (*p < 0.05, ***p < 0.001), (D) FTIR spectra of the TArg after exposure to calculus, and (E) Schematic diagram representing the reaction between aragonite (TArg) and dental calculus

Fig. 6

characterization of dental calculus surface before and after exposure to TArg slurry. A, B SEM micrographs of calculus before and after exposure to TArg slurry. C 3D optical surface profiler showing changes of surface roughness of calculus as a result of TArg exposure. D GA-XRD showing the changes of crystallinity of calculus after exposure to TArg slurry [DCPD: Brushite (Dicalcium phosphate dihydrate, (CaHPO₄·2H₂O) and DCPA: Monetite (Dibasic calcium phosphate anhydrate, CaHPO₄)]. E EDX analysis showing the changes of elemental composition of calculus before and after 1 h of exposure to TArg slurry (*p < 0.05)

Fig. 7

Abrasion depth of (A); TArg slurry, (B); toothpaste containing TArg, and (C); Colgate Total toothpaste on enamel, dentin, and calculus, (D); the amount that was removed by each of them (*p 0.05)