Evaluation of Salivary Biochemistry in Dogs with and without Plaque, Calculus, and Gingivitis: Preliminary Results

SIMPLE SUMMARY: Periodontal disease is one of the most prevalent disorders observed in dogs requiring primary-care veterinary services. Traditional methods for its diagnosis involve clinical measurements requiring sedation or general anesthesia. The aim of this study was to evaluate whether quantified salivary biochemistry parameters can be used as markers of periodontal disease in dogs. Seventy-nine dogs were allocated into three groups according to the severity of periodontal disease: none (Group 1), moderate (Group 2), and severe (Group 3). A blood sample and a saliva sample were collected from each dog to quantify biochemical parameters that included alpha-amylase, lysozyme, lactate dehydrogenase (LDH), calcium, and phosphorus. LDH and phosphorus showed the highest values in Group 3 whereas calcium, amylase, and lysozyme did not differ among groups. The salivary phosphorus cut-off value of 4.04 mg/dl that was established signified that above such value, periodontal disease could be predicted with fairly high probability. Although further studies are needed to confirm these preliminary results, this study offers a valid starting point for further investigation into the role of saliva as a non-invasive tool for detecting periodontal disease in dogs. ABSTRACT: This study evaluated whether salivary alpha-amylase, lysozyme, lactate dehydrogenase (LDH), calcium, and phosphorus can be used as markers of periodontal disease in dogs. Plaque, calculus, and gingivitis indexes were used to allocate 79 dogs in three groups: none (Group 1), moderate (Group 2), and severe (Group 3) periodontal disease. A blood sample and a saliva sample were collected from each dog to quantify biochemical parameters. LDH and phosphorus showed the highest values in Group 3 (LDH: Group 1, 2559.85 ± 676.95; vs. Group 2: 1636.76 ± 597.36 vs. Group 3: 4099.18 ± 545.45 U.I./l, p = 0.016; phosphorus: Group 1, 3.02 ± 0.76 vs. Group 2: 5.34 ± 0.67 vs. Group 3: 5.85± 0.61 mg/dl, p = 0.049) whereas calcium, amylase, and lysozyme did not differ among groups. A ROC curve analysis permitted the establishment of a salivary phosphorus cut-off value of 4.04 mg/dl, above which periodontal disease could be predicted (70% sensitivity (95% CI: 50.6–85.3%) and 72.41% specificity (95% CI: 52.8–87.3%)). Only salivary calcium was higher in males; no other salivary parameters appeared affected by gender or age. Although further results on a larger population are needed, this study shows that salivary LDH and phosphorus increase in dogs affected by plaque, supragingival calculus, and gingivitis, and this suggests their potential use as markers of periodontal disease in canine species.