Compatibility of salivary lactate dehydrogenase level using a test kit with the community periodontal index in Japanese adults

The purpose of this study was to investigate the association between salivary lactate dehydrogenase (LD) levels, assessed using a test kit, and the community periodontal index (CPI) and to determine the feasibility and reliability of the test kit for screening periodontal disease in adults. The study included 205 patients (58.5% female, median and 25–75 percentiles of age 55.0, 46.0–66.0 years) who visited two university hospitals and one university clinic in Japan. Resting saliva sample was collected from each participant, and LD level was evaluated in real time using a kit featuring an integer scale ranging from 1 to 10. Individual pocket scores were categorized as follows: score = 0 (≤ 3 mm), score = 1 (4–5 mm), and score = 2 (≥ 6 mm) and gingival bleeding scores were categorized as follows: score = 0 (absence of condition) and score = 1 (presence of condition). Notably, 120 participants (58.5%) exhibited a pocket score = 1 or 2, and 123 participants (60.0%) exhibited a gingival bleeding score = 1. The optimal cutoff values for salivary LD level to distinguish pocket scores = 1 or 2 from 0 and score = 2 from 0 or 1 were 4.0 and 5.0, respectively, with a sensitivity and specificity of ≥ 0.65. The median salivary LD level for a gingival score = 1 was significantly higher than that for gingival score = 0, and the optimal cutoff value for the salivary LD level was 4.0, with a sensitivity and specificity of ≥ 0.62. Our results suggested that a salivary LD level ≥ 4.0 in adults may suggest the presence of periodontal disease, thereby emphasizing the kit`s utility as a screening tool.