The Role of Plaque and Calculus in the Etiology of Periodontal Disease

Conversations with the veterinary portion of the FDA the question was raised- “Is calculus an etiological agent?” To answer this question a longitudinal pilot study was designed using 11 privately owned dogs. The study received IACUC approval. Informed consent was obtained from the owners. Objectives: 1) evaluate daily oral hygiene in the presence of calculus; 2), evaluate daily oral hygiene in a clean tooth model; 3) evaluate the progress of gingivitis with out oral hygiene. Methods: Standard methodology was used for all oral exams for gingivitis, plaque, and calculus. Baseline exams were conducted at day 0. Owners were instructed to brush their dog’s teeth daily (days 0-20) with the toothbrush provided and tap water. Oral exams were conducted after 21 days. Following each exam, the dog received a complete dental prophylaxis. Owners were instructed to brushing their dog’s teeth for an additional 21 days. At the end 3-week brushing period, dogs were examined for all oral parameters. All oral hygiene was suspended for the last 3 weeks. At 9 weeks, all dogs were examined for all oral parameters. The data was analyzed using repeated measures ANOVA with instructed covariance matrix and Sidak method for multiple comparisons. Results: (Mean ± SEM) Gingivitis Baseline 1.25±0.08, 3 weeks 0.91±0.06, 6 weeks 0.72±0.05, 9weeks 1.10±0.06; Plaque Baseline 12.27±1.21, 3 weeks 10.72±1.13, 6 weeks 6.02±0.37, 9weeks 10.65±0.84; Calculus Baseline 11.34±2.33, 3 weeks 10.43±1.96, 6 weeks 1.59±0.34, 9weeks 4.27±0.70. Conclusions:(1) gingivitis could be significantly reduced by daily oral hygiene in the presence of calculus; (2) following a complete dental prophylaxis plus 3 additional weeks of daily oral hygiene could further significantly reduce gingivitis; (3), 3 weeks following cessation of daily oral hygiene gingivitis returned to baseline levels; (4) primary etiological agent for gingivitis is dental plaque, and (5), dental calculus is not a significant ethological factor.