Relationship between Acid Neutralization Capacity of Saliva and Gastro-Oesophageal Reflux

Abstract

Saliva is an important factor in neutralization of oesophageal acid exposure, clinically manifested as gastrooesophageal reflux (GOR). The aim of this study is to compare the composition and the "capacity in acid neutralization" (CAN) of saliva in controls and patients suffering of GOR. We compared the composition of saliva from 56 patients who had symptoms of GOR with that of saliva from 20 healthy control subjects. After a standardized 24-hour period of pH-monitoring, 39 patients had normal pH reflux scores (normal acid score: NAc-GOR) and 17 had abnormal pH reflux scores (pathological acid score: PAc-GOR). Then, following a 10-h fast, total saliva was collected during ten minutes in all patients and in the healthy control subjects. The composition of the saliva samples was analysed and the titration curve was determined on 200 microliters aliquots by successive addition of 5 microliters volumes of 0.1 N Hcl. The GOR patients had significantly lower salivary concentrations of Na+ and of both free and bound sialic acids and had higher salivary concentrations of inorganic phosphates than the controls. These disorders were more marked in PAc-GOR patients. Initial pH was 7.43 +/- 0.43 in controls, 7.35 +/- 0.45 in NAc-GOR patients, and 6.91 +/- 0.53 in PAc-GOR patients. In the beginning of the titration curve, PAc-GOR patients were significantly different from NAc-GOR patients and from controls. Saliva of both groups of patients presented significant differences in the acidic portion of the titrations curves, at high volumes of added HCl. These data show that the composition of saliva was modified in patients with GOR disease compared to that of normal subjects. A difference in titration curves was also observed with a higher acidic buffering capacity in these GOR patients. The modifications in saliva composition suggest a role for inorganic phosophates in the acid neutralization capacity observed in GOR, perhaps linked with a adaptation to chronic acid exposure.

A nocturnal decline of salivary pH associated with airway hyperresponsiveness in asthma

“…Saliva is an important determinant of esophageal acid neutralization in GER (8). We demonstrated that there is a significant correlation between ED50 and a nocturnal fall in salivary pH (ΔpH), but not initial salivary pH measured during the daytime, in both healthy and mildly asthmatic subjects.…”

“…Dental erosion, which is caused by acid exposure in GER, shows an association with acidity in saliva (7). The initial salivary pH is correlated with pH in the lower esophagus and is higher in GER subjects than in control subjects (8). In addition, Katz et al (9) ORIGINAL A nocturnal decline of salivary pH associated with airway hyperresponsiveness in asthma Naoto Burioka 1 , and Eiji Shimizu detected nocturnal gastric acid breakthrough (NAB), defined as nighttime periods exceeding 1 h with a gastric pH below 4.0, in 67% of normal subjects ; and it was previously reported that there is a nocturnal decline of salivary pH in healthy subjects (10).…”

“…In addition, Katz et al (9) ORIGINAL A nocturnal decline of salivary pH associated with airway hyperresponsiveness in asthma Naoto Burioka 1 , and Eiji Shimizu detected nocturnal gastric acid breakthrough (NAB), defined as nighttime periods exceeding 1 h with a gastric pH below 4.0, in 67% of normal subjects ; and it was previously reported that there is a nocturnal decline of salivary pH in healthy subjects (10). Saliva is an important determinant of esophageal acid neutralization in patients with NAB as well as in GER patients (8).…”

Clinical Study Monitoring the pH on Tooth Surfaces in Patients with and without Erosion

“…The collected saliva samples were immediately frozen at -20 ° C. Later they were thawed and titrated with 0.1 N HCl from initial pH to pH 7.0, 5.5, 4.0 and 3.0 using 4 g of saliva for each analysis [Bouchoucha et al, 1997] (Microlab , Bonaduz, Switzerland). Buffering capacity ( ␤ ) was calculated as ␤ = ͉ ⌬ C/ ⌬ pH ͉ , where ⌬ C is the amount of the acid used and ⌬ pH is the change in pH caused by the addition of the titrator.…”

A potentiometric disposable sensor strip for measuring pH in saliva

“…Accessible body fluids such as saliva represent an interesting medium for the realization of body-sensing, as these fluids also contain important personal physiological information [13][14][15][16][17][18][19][20]. Continuous monitoring of pH in saliva would be extremely beneficial for maintaining healthy mouth conditions, e.g., degradation of tooth enamel [21] and detection of Gastroesophageal Reflux Disease (GERD) [22][23][24], as well as drug activity, as in some cases this can depend on saliva pH [17].…”