Effect and Stability of Poly(Amido Amine)-Induced Biomineralization on Dentinal Tubule Occlusion.

Yuan Gao,He Yuan,Jianshu Li,Xiaolei Duan,Kunneng Liang,Jiyao Li,Hongling Liu

doi:10.3390/ma10040384

Abstract

In recent years, scientists have developed various biomaterials to remineralize human teeth to treat dentine hypersensitivity. Poly(amido amine) (PAMAM) dendrimers have become a research focus in this field. It has been demonstrated that PAMAM is able to create precipitates both on the surface of and within the dentinal tubules, however, there is little information about its effect on reducing dentine permeability in vitro. This study aimed to evaluate the in vitro effectiveness and stability of the fourth generation amine-terminated PAMAM on dentinal tubule occlusion, especially on dentine permeability. Sodium fluoride (NaF), which has been widely used as a desensitizing agent, is regarded as positive control. Demineralized sensitive dentine samples were coated with PAMAM or sodium fluoride solutions and soaked in artificial saliva (AS) at 37 °C for different periods. Four weeks later, samples in each group were then equally split into two subgroups for testing using a brushing challenge and an acid challenge. Dentine permeability of each specimen was measured before and after each challenge using a fluid filtration system. Dentine morphology and surface deposits were characterized by scanning electron microscope (SEM) and analyzed with Image-Pro Plus software. Data were evaluated through multifactorial ANOVA with repeated measures and pair-wise comparisons at a level of 5%. The results showed that PAMAM and NaF significantly reduced dentine permeability to 25.1% and 20.7%. Both of them created precipitates on dentine surfaces after AS immersion for 28 days. PAMAM-induced biomineralization not only on dentine surfaces, but also deeper in dentinal tubules, significantly reduced dentine permeability. Moreover, PAMAM-induced biomineralization elicited excellent stable occlusion effects after acid challenge. In conclusion, PAMAM demonstrated a strong ability to resist acid and showed great potential to be used in the treatment of dentine hypersensitivity in future.

Highlights

Dentine hypersensitivity is a common dental problem caused by the exposure of dentinal tubules that allow the movement of intradentinal fluid [1]
Sodium fluoride reduces dentine permeability within a short period [14], some studies have shown that the mode of action of fluoride occurs through precipitation of calcium fluoride crystals within the tubules [15], and these crystals are not resistant to removal through the action of saliva, brushing, or food substances [16]
Optimum desensitizing agents for dentine hypersensitivity treatments should reduce dentine permeability and maintain occlusion effects when dentine is subjected to acid challenge and abrasion [18]

Summary

Introduction

Dentine hypersensitivity is a common dental problem caused by the exposure of dentinal tubules that allow the movement of intradentinal fluid [1]. Some studies have shown that hypersensitivity occurred on the exposed dentine when most of the tubular orifices were open [8,9], and hypersensitive teeth showed highly significantly increased numbers of tubules per unit area compared with non-sensitive teeth. Sodium fluoride reduces dentine permeability within a short period [14], some studies have shown that the mode of action of fluoride occurs through precipitation of calcium fluoride crystals within the tubules [15], and these crystals are not resistant to removal through the action of saliva, brushing, or food substances [16]. Optimum desensitizing agents for dentine hypersensitivity treatments should reduce dentine permeability and maintain occlusion effects when dentine is subjected to acid challenge and abrasion [18]. In vitro studies have revealed that the risk of dentine hypersensitivity may increase in the presence of dietary acids [19,20]

Objectives

Discussion

Conclusion