The oral cavity has specific and individualized characteristics, with pH, saliva flow, buffer capacity, temperature, and microorganisms content influencing oral health. Currently, the prevalence of gastroesophageal reflux disease (GERD) is constantly increasing. The objective of this study was to evaluate and compare the saliva quantity at 5 min, salivary pH, and salivary buffer capacity in patients with and without GERD, necessary for establishing the correct dental treatment plan. A Saliva-Check Buffer (GC) kit was used for the determination of salivary variables. The total number of 80 patients included in the study were divided into a study group and a control group, each containing 40 patients. Saliva quantity at 5 min was lower in patients suffering from GERD. The salivary pH of these patients turned to acid values compared to the salivary pH of controls, where the values were within the normal range. In patients with GERD, the determined salivary buffer capacity was low or very low. The use of the Saliva-Check Buffer (GC) kit is a simple, easy, non-invasive and patient-accepted method, which can also be used in the dentist’s office to assess the saliva buffer capacity and pH, variables that are important for establishing a correct dental treatment plan.