## 3 Materials and Methods
### Study Design  
The study design was built according to case-control study methodology. We used clinical and paraclinical data extracts from the paper observation documents of the patients present at the request of our study to which we added information from measurements recorded for pH and salivary flow, respectively. These data are important for dentists because a post-radiotherapy cancer patient often requires complex oral rehabilitation. The methodology of case-control studies is where the selection of patients is conmk-secutive to those presented in person for oral rehabilitation therapy. * Inclusion criteria for the cases were as follows: patients suffering from oral cancer post-radiotherapy, that had a dose of irradiation between 60 Gray (Gy) and 70 Gy, depending on the specifics of each patient, presenting after a minimum interval of 2-3 months post-radiotherapy cure. In our area, NE part of Romania, the external beam radiation therapy (EBRT) with IMRT (intensity modulated radiotherapy) technique is commonly used. Doses are reported in 60 Gy/30 fractions/6 weeks, 70 Gy/35 fractions/7 weeks, or 66 Gy/33 fractions/6.5 weeks, 2 Gy/fraction [16,17]. * The exclusion criteria for the cases were as follows: non-cancer patients (other pathologies might exist); non-cooperating patients; patients with advanced or terminal illnesses; incapacitated patients for scheduled procedures; and patients with medication that induces hyposulivation. The SFR is an indicator of xerostomia after radiotherapy in patients with oral cancer. Salometry encompasses a range of diagnostic tests aimed at evaluating the rate of salivary secretion (quantitative sialometry) and analyzing its composition (qualitative sialometry), it is an important tool in the rehabilitation treatment plan. After radiotherapy, in patients with oral cancer, sialometry and salivary pH monitoring were necessary for estimating the risk of dental caries and to establish a complex oral rehabilitation plan. Prior to saliva harvesting, subjects were instructed to refrain from eating, drinking, and smoking. 3.1.1. The pH Measurement  
Determination of the salivary pH was carried out directly using a digital pH meter (APH 20 model). The accuracy of the pH meter was calibrated using standard buffers (pH 4.7 and 10) to ensure the correct measured values. 3.1.2. The RSF Measurement  
Determination of RSF rate (the procedure was realized in triplicate, recording the mean value) was performed by the following method: the patient sat in the dental chair with their head was slightly bent forward, and then they were asked to swallow the saliva accumulated in their oral cavity, after which the timer was started. The patient removed accumulated saliva every minute into a beaker; after 5 min, the amount of accumulated saliva was measured. Normal values range between 0.25-0.35 mL/min according to data in the literature [18]. 3.1.3. The SSF Measurement  
Determination of stimulated salivary flow (SSF) rate (the procedure was realized in triplicate, recording the mean value) was carried out according to the following method: the patient was sitting in the dental chair as in the previous test and was asked to chew for 60 s, and then swallow the accumulated saliva. The timing started after one minute, leaving the patient to evacuate saliva in a graduated beaker for 5 min. The volume was expressed as mL/minute. Normal values lie in the range 1-1.5 mL/min [18; 19]. 3.2. General Clinical Investigation Methods Used for Stomatogatic System Area  
The clinical methods used in our study were important for periodontal status analysis, caries detection, endodontic evaluation, and prosthetic treatment staging, established for the achievement of homeostasis in the post-radiotherapy context. 3.2.1.