Ultrastructure of the Dentin Pellicle and the Impact of Erosion

Abstract

While the ultrastructure of the enamel pellicle and its erosion protective properties are well studied, the dentin pellicle is still neglected in dental research. Therefore, the ultrastructure and erosion protective properties of a pellicle formed on bovine dentin specimens was investigated in the present study. The dentin pellicle was formed in-situ for 3, 30, 120, and 360 min at buccal or palatal oral sites of 3 subjects and analyzed by transmission electron microscopy. In order to clarify the impact of an erosive challenge to the ultrastructure of the pellicle and the underlying dentin, specimens were exposed to the oral cavity and eroded in-vivo with 0.1% or 1% citric acid either immediately or after 30 min of pellicle formation. Specimens that were eroded without exposure to the oral cavity served as control. In another trial, specimens with a 30-min pellicle were exposed to the oral cavity for a further 60 min after the erosive challenge to investigate the effect of saliva on the impaired pellicle and dentin. Transmission electron micrographs reveal a globular and granular structured pellicle layer, which was thicker when the pellicle was formed buccally or with longer formation times. Erosion with citric acid reduced the thickness of the pellicle and interrupted its continuity. The dentin was also affected by erosion, which was represented by a lower electron density and formation of demineralized lacunae. These were infiltrated by a granular structured material when specimens were exposed to the oral cavity. After further intraoral exposure, the infiltration was more pronounced, indicating a significant impact of saliva on the demineralized dentin. A reformation of the dentin pellicle on the other hand did not occur. In conclusion, the dentin pellicle is neither acid-resistant nor able to effectively protect dentin from erosion.

Effect of Polyphenols on the Ultrastructure of the Dentin Pellicle and Subsequent Erosion

“…The pellicle and in particular the basal layer acts as a diffusion barrier, thereby protecting enamel against dental erosion [11]. In contrast, the protective properties of the dentin pellicle are controversially discussed [12], which could be related to the missing basal layer [13]. A promising approach to enhance the protective properties of the pellicle is the modification of its ultrastructure by polyphenols.…”

The composition of the dental pellicle: an updated literature review

“…This might influence the mechanical properties of the teeth ( 24 ). However, full protection of the teeth by the pellicle is not possible ( 25 ). Hara et al showed that the dental pellicle formed after 2 h can protect teeth from demineralization due to erosive challenge for 10 min, but not a longer period.…”