Time-related Changes in pH, Buffering Capacity and Phosphate and Urea Concentration of Stimulated Saliva.

PURPOSE: To quantify changes in pH, buffering capacity and hydrogen carbonate, phosphate, protein and urea concentrations of stimulated saliva which occur during a 30-min measurement delay after saliva collection. The correlation between time-related chemical changes and changes of salivary pH and buffering capacity was assessed in order to explain the observed changes in salivary pH and buffering capacity. MATERIALS AND METHODS: Stimulated saliva samples were collected from 30 volunteers after inducing salivation by chewing a piece of parafilm. Measurements of salivary variables were made immediately after saliva collection and again 30 min later, during which time the specimens were exposed to the atmosphere in collection cups at room temperature. RESULTS: Postponement of measurements resulted in a significant increase in pH and a significant decrease of buffering capacity, phosphate and urea concentration. The results suggest that the time-related pH increase could primarily be attributed to loss of dissolved carbon dioxide from saliva, and confirm the importance of hydrogen carbonate in the neutralisation of hydrogen ions, but they do not support the principle of catalysed phase-buffering for the hydrogen carbonate buffer system in saliva. A decrease in phosphate and urea concentration affects salivary buffering capacity. CONCLUSION: This study emphasises the importance of the standardisation of measurement time when measuring salivary pH, buffering capacity, phosphate and urea concentrations following the collection of saliva in order to obtain comparable results. It also provides a partial explanation of the mechanisms underlying the observed changes of pH and buffering capacity over time.

Efficacy and safety of an intraoral electrostimulation device for xerostomia relief: a multicenter, randomized trial.

OBJECTIVE: To evaluate the efficacy and safety of an intraoral electrostimulation device, consisting of stimulating electrodes, an electronic circuit, and a power source, in treating xerostomia. The device delivers electrostimulation through the oral mucosa to the lingual nerve in order to enhance the salivary reflex. METHODS: The device was tested on a sample of patients with xerostomia due to Sjögren's syndrome and other sicca conditions in a 2-stage prospective, randomized, multicenter trial. Stage I was a double-blind, crossover stage designed to compare the effects of the electrically active device with the sham device, each used for 1 month, and stage II was a 3-month open-label stage designed to assess the long-term effects of the active device. Improvement in xerostomia severity from baseline was the primary outcome measure. RESULTS: A total of 114 patients were randomized. In stage I, the active device performed better than the sham device for patient-reported xerostomia severity (P<0.002), xerostomia frequency (P<0.05), quality of life impairment (P<0.01), and swallowing difficulty (P<0.02). At the end of stage II, statistically significant improvements were verified for patient-reported xerostomia severity (P<0.0001), xerostomia frequency (P<0.0001), oral discomfort (P<0.001), speech difficulty (P<0.02), sleeping difficulty (P<0.001), and resting salivary flow rate (P<0.01). CONCLUSION: Our findings indicate that daily use of the device alleviated oral dryness, discomfort, and some complications of xerostomia, such as speech and sleeping difficulties, and increased salivary output. The results show a cumulative positive effect of the device over the period of the study, from baseline to the end of the trial.

Effect of occlusal splint on oxidative stress markers and psychological aspects of chronic temporomandibular pain: a randomized controlled trial.

Temporomandibular disorders (TMD), when progress to a chronic state, might contribute to psychosocial or psychological distress. This study aimed to evaluate the effect of stabilization splint (SS) therapy on pain, pain-related disability and psychological traits of chronic TMD patients, as well as to assess selected oxidative stress (OS) biomarkers during 6-month treatment and associate them with the symptoms of anxiety and depression. Thirty-four participants were randomly assigned into two treatment groups [SS and placebo splint (PS)]. Primary outcomes were pain intensity and pain-related disability while secondary outcomes included depressive and anxiety symptoms. The influence of the treatment type was analyzed with regards to the levels of OS biomarkers in saliva. Participants treated with SS demonstrated significantly greater improvement in pain-related disability (Pain-free mouth opening: p = 0.018, η2 = 0.166; Number of disability days: p = 0.023, η2 = 0.155) and greater reduction of depressive symptoms scores (p = 0.007, η2 = 0.207). When compared to the PS group, participants in the SS group showed a significant reduction of oxidant/antioxidant ratio (p = 0.018, η2 = 0.167) at a 3-month follow-up. A stabilization splint provides advantages over PS in the treatment of depressive symptoms and pain-related disability. Furthermore, clinical success in terms of reduction of depressive symptoms, which correlates with the reduction of oxidative stress markers in the SS group, indicates that oxidative stress is related to psychological factors in chronic TMD patients.

The rise in glucose concentration in saliva samples mixed with test foods monitored using a glucometer: An observational pilot study.

OBJECTIVES: The aim of this study was to quantify the changes in glucose concentration in unstimulated saliva samples mixed with finely crushed salted sticks or oat meal using a readily available portable glucometer. METHODS: Glucose measurements were taken every 10 min during a 1 h monitoring period, for a total of 14 saliva samples mixed with test foods. Salivary amylase activity was measured immediately after saliva collection (T0) and after 1h (T60). Level of salivary amylase activity was correlated with an increase in glucose concentration. RESULTS: We observed significant differences in the rate of increase in glucose concentration between the two different test foods, with salted sticks leading to greater increase in glucose concentration. No significant association was found between salivary amylase activity and the rate of increase in glucose concentration. The mean level of amylase activity at T60 was higher than that at T0, but this difference was not significant. CONCLUSIONS: This pilot study presents glucose release rate characteristics from specific food particles mixed with saliva in vitro suggesting that the same process takes place in the oral cavity. However, the characteristics of this process when occurring in the mouth would expectedly be modified by different factors such as rinsing effect of salivary flow, oral temperature, etc. Prolonged release of low molecular carbohydrates such as maltose and glucose from food particles can be considered cariogenic and therefore unfavorable for individuals with other risk factors contributing to the development of dental caries.

Salivary Oxidant/Antioxidant Status in Chronic Temporomandibular Disorders Is Dependent on Source and Intensity of Pain - A Pilot Study.

Temporomandibular disorders (TMD) have been associated with altered salivary oxidative status, but the relation with pain source and pain severity isn't clarified. With the aim to assess their interaction with TMD, we compared levels of selected salivary oxidative stress (OS) markers (glutathione peroxidase, superoxide dismutase, total antioxidant capacity (TAC), uric acid, 8-hydroxydeoxyguanosine, malondialdehyde) and salivary cortisol (SC) as a stress indicator, between 20 TMD patients and 15 healthy control subjects. In order to record differences relating to pain source and severity, patients were respectively classified according to specific diagnoses (myofascial pain or disc displacement (DD)), and pain intensity (high or low). TAC was significantly higher in TMD patients than in controls (morning p = 0.015; afternoon p = 0.005). Significant differences were also observed when TAC levels between high-intensity pain patients and controls were compared, as well as between DD patients and controls. In logistic regression analysis, higher levels of TAC were related to DD (morning OR: 1.66, 95%CI: 1.05-2.64, p = 0.029; afternoon OR: 2.10, 95%CI: 1.11-3.98, p = 0.021) and to high-intensity pain (morning OR: 1.81, 95%CI: 1.04-3.15, p = 0.037; afternoon OR: 1.79, 95%CI: 1.02-3.14, p = 0.043). We also found that morning SC was positively correlated with antioxidant parameters in TMD patients. Our data suggest compensatory mechanism as response to higher level of stress. This stress could be extrinsic and lead toward TMD, or intrinsic, emerging from established TMD, or could be both. The intensity and the source of pain should be considered important factors in future investigations evaluating salivary OS markers in TMD patients.

Within-Subject Reliability and between-Subject Variability of Oxidative Stress Markers in Saliva of Healthy Subjects: A Longitudinal Pilot Study.

The present study evaluated diurnal variations and day-to-day fluctuations of salivary oxidative stress (OS) markers in healthy adult individuals. Whole unstimulated saliva was collected at 2 time intervals over 3 consecutive days. Glutathione peroxidase (GPX), superoxide dismutase (SOD), total antioxidant capacity (TAC), and uric acid (UA) were analyzed using spectrophotometric methods, while 8-hydroxydeoxyguanosine (8-OHdG) and malondialdehyde (MDA) were determined using immunoassays. No significant differences for salivary OS markers between men and women were observed. For all examined OS markers, no significant day-to-day variations were demonstrated. Significant diurnal variations were found in salivary GPX, TAC and MDA levels. For SOD, TAC, GPX, and UA, good-to-moderate intraindividual coefficients of variations (CVs) were observed in more than 75% of the subjects. For MDA and 8-OHdG, intraindividual CVs > 35% were observed in 60% and 40% of the subjects, respectively. Between-subject variance was wide for all examined OS markers (CV% 30.08%-85.70%). Due to high intraindividual variability in the salivary concentrations of MDA and 8-OHdG, those markers cannot be reliably verified based on single measurements and multiple measurements over several days would provide more reliable information. Salivary SOD, TAC, GPX, and UA proved stable across three days of measurement. Trial Registration. ClinicalTrials.gov NCT03029494. Registered on 2017-01-19.

Intraoral electrostimulator for xerostomia relief: a long-term, multicenter, open-label, uncontrolled, clinical trial.

OBJECTIVE: A previous sham-controlled multinational study demonstrated the short-term efficacy and safety for xerostomia treatment of an intraoral device that delivers electrostimulation to the lingual nerve. The objective of this study was to test the hypothesis that those beneficial effects would be sustained over an 11-month period. STUDY DESIGN: The device was tested on a mixed sample of 94 patients with xerostomia in an open-label, uncontrolled, prospective multicenter trial. Statutory outcome assessments were done at 5th, 8th, and 11th months and analyzed by multiple comparisons. RESULTS: Improvements achieved at month 5 from baseline were sustained throughout the follow-up period for the primary outcome, xerostomia severity, and the secondary outcomes resting whole salivary flow rate, xerostomia frequency, oral discomfort, and difficulties in speech, swallowing, and sleeping. No significant side effects were detected. CONCLUSIONS: The beneficial effects of a removable intraoral electrostimulating device were sustained for an 11-month period.