Composition of enamel pellicle from dental erosion patients.

Oral health is dependent upon a thin mobile film of saliva on soft and hard tissues. Salivary proteins adhere to teeth to form the acquired enamel pellicle which is believed to protect teeth from acid erosion. This study investigated whether patients suffering diet-induced dental erosion had altered enamel pellicles. Thirty patients suffering erosion were compared to healthy age-matched controls. Subjects wore a maxillary splint holding hydroxyapatite and human enamel blocks for 1 h. The acquired enamel pellicle was removed from the blocks and compared to the natural incisor pellicle. Basic Erosive Wear Examination scores confirmed that dental erosion was present in erosion patients and absent from healthy age-matched controls. Erosion patients had half the amount of proteins (BCA assay) within the acquired pellicle forming on splint blocks compared to normal controls (p < 0.05). In particular, statherin, a calcium-binding protein, was 35% less abundant (p < 0.05). Calcium concentration within the acquired pellicle was also reduced by 50% in erosion patients (p < 0.001). In contrast, the natural pellicle on the incisor had similar amounts of total protein in erosion patients and healthy controls. In summary, the formation of new acquired pellicles on surfaces was reduced in erosion patients, which may explain their greater susceptibility to acid erosion of teeth.

Comparison of the possible protective effect of the salivary pellicle of individuals with and without erosion.

The acquired pellicle adheres to tooth surfaces and has been suggested to provide differing degrees of protection against acidic erosion. This study investigated whether pellicle formed on enamel blocks in patients suffering dietary dental erosion modified the effect of an in vitro simulated dietary challenge, in comparison with pellicle formed on enamel blocks in healthy subjects and to no-pellicle enamel samples. Sixty subjects recruited from dental erosion clinics were compared to healthy age-matched controls. Subjects wore a custom-made maxillary splint holding human enamel blocks for 1 h during which the acquired enamel pellicle was formed. Enamel blocks were removed from the splints and a simulated dietary erosive challenge of 10 min was performed. In addition the challenge was performed on 30 enamel samples without pellicle. Profilometry showed no statistical difference between samples from the erosion subjects with a mean step height of 1.74 µm (SD 0.88) and median roughness (Sa) of 0.39 µm (interquartile range, IQR 0.3-0.56) and the controls with 1.34 µm (SD 0.66) and 0.33 µm (IQR 0.27-0.38), respectively. The control samples without pellicle had Sa of 0.44 µm (IQR 0.36-0.69) and these differences were statistically significant compared to those from the healthy subjects (p = 0.002). Mean (SD) microhardness reduction with a 100-gram load for the erosion group was 113.5 (10) KHN, for healthy subjects was 93 (15.4) KHN and for the enamel samples without pellicle 139.6 (21.8) KHN and all groups were statistically different. The microhardness and roughness data suggested the pellicle influenced erosion under these study conditions.