Dentine hypersensitivity: effect of interactions between metal salts, fluoride and chlorhexidine on the uptake by dentine

Abstract

A large number of compounds may be applied to the teeth for preventive or therapeutic purposes, most notably in dentine hypersensitivity. The uptake of any one compound by tooth substances may clearly be affected by another to produce synergistic, additive or antagonistic effects. This study determined whether uptake interactions occurred between fluoride, chlorhexidine, strontium, tin and zinc. All compounds, in particular tin, showed considerable affinity for dentine. Fluoride reduced the uptake of zinc but not tin, strontium or chlorhexidine. Chlorhexidine increased the uptake of zinc, but not tin, strontium or fluoride. Zinc and tin decreased fluoride uptake but strontium had no such effect. Finally, chlorhexidine uptake was increased by zinc and tin but not by fluoride or strontium. Based on the theories proposed for the reaction of these various compounds with calcified tissues, explanations for the interactions can be made. The results appear relevant to some reported clinical effects of combinations of these compounds and indicate that such interactions may have advantageous or disadvantageous consequences depending on the basis for treatment.

Effectiveness of various toothpastes on dentine tubule occlusion

“…42 Some studies have demonstrated decreased hydrodynamic fluid flow within the dentine tubules upon oxalate treatment, thus reducing pain sensations. 41,[43][44][45][46] Another study demonstrated that oxalates block dentinal fluid flow by forming precipitates within the dentine tubules. 47 However, a systematic review regarding the effectiveness of oxalates in the treatment of dentine hypersensitivity determined that that single treatments of oxalates had no effect on dentine hypersensitivity compared to placebos.…”

A comparison of a reformulated potassium citrate desensitising toothpaste with the original proprietary product

“…This is interesting in that the additional agents included a zinc salt and zinc salts appear able to adhere to dentine and occlude tubules, although this precipitate is labile in water. 24 Importantly, within the main aim of the study, the data show that the addition of anti-plaque agents to the desensitising product had no adverse effect on the efficacy. Clearly, it would have been of interest to record plaque and gingivitis levels throughout the study.…”

Oral hygiene products: potential for harm to oral and systemic health?

“…There are many clinical trials concerning the efficacy of a number of ‘actives’ in the treatment of dentine hypersensitivity, albeit mostly with equivocal or contradictory findings (for reviews see 4, 70). There are, however, no studies in vivo that reveal what is actually occurring at the dentine surface following toothbrushing with various toothpastes.…”

“…These latter products have artificial silica‐based abrasive systems with alternative detergents to the usual anionic agent (sodium lauryl sulphate), a detergent that appears to compete with silica for attachment to the dentine surface. Evidence for dentine hypersensitivity actives in toothpastes that block tubules is completely lacking, although experiments using ‘actives’ in solution, such as stannous salts, indicate that tubules can be blocked (4).…”

“…• the toothpaste could abrasively or chemically remove the smear layer and initiate dentine hypersensitivity; • the toothpaste could abrade the dentine and create a smear layer, essentially preventing dentine hypersensitivity; • the abrasive particles in the toothpaste could chemically attach to the dentine surface or be forced into the tubules by the action of the brush, both processes essentially preventing dentine hypersensitivity; or • desensitizing agents in the toothpaste could block tubules or permeate the dentine to block neural transmission at the dentine ⁄ pulp junction. There are many clinical trials concerning the efficacy of a number of ÔactivesÕ in the treatment of dentine hypersensitivity, albeit mostly with equivocal or contradictory findings (for reviews see 4,70). There are, however, no studies in vivo that reveal what is actually occurring at the dentine surface following toothbrushing with various toothpastes.…”