Salivary Proteins in Human Acquired Enamel Pellicle (AEP) on Eroded and Uneroded Teeth in Patients with Gastro-Oesophageal Reflux Disease (GORD)

The aim of this in vivo study was to compare total protein present in the salivary films (F) and acquired enamel pellicle (AEP) on eroded and non-eroded surfaces in patients suffering from GORD symptoms with and without GORD diagnosis (GORD, No-GORD). Thirty-nine patients suffering from GORD symptoms and erosive tooth wear on lower first molars and an unaffected posterior occlusal surface in the same quadrant were recruited from Guy's hospital, London. Salivary film and AEP were collected from the eroded and uneroded occlusal surfaces, using 0.5% sodium dodecyl sulphate (SDS)-soaked filter papers. Total protein concentration was analysed using bicinchoninic acid assay (BCA). Statistical analysis was conducted using Shapiro-Wilk, ANOVA, and Tukey's tests (p < 0.05), comparing four GDS sample types and GORD vs. No-GORD groups. The level of significance was set as p < 0.05. Data were compared between eroded and uneroded surfaces in the same patient with GORD symptoms, as well as between those with or without a GORD diagnosis (GORD, No-GORD). The AEP total protein concentration from the eroded [2.17 (0.49) mg/mL] and uneroded surfaces [2.24 (0.66) mg/mL] of the GORD group were statistically significantly lower than those on eroded [3.27 (1.01) mg/mL] and uneroded [3.33 (1.57) mg/mL] surfaces in the No-GORD group (p = 0.007) (p = 0.008), respectively. No statistically significant differences were observed for film and AEP between eroded and uneroded surfaces (p > 0.05).