Development of dental plaque on the incisor teeth of monkeys (Macaca fascicularis )

Abstract Bacterial plaque which had accumulated for 0.5, 1, 2, 4, 7, 14 and 28 days was cultured from the labial surface of one of the central incisor teeth in 15 monkeys ( Macaca fascicularis ). Each sampling area was defined by a metal well contained within a custom-made removable acrylic block. The number (log 10 ) of the total colony forming units (c.f.u.) increased significantly from 3.40 to 6.02 between 0.5 and 28 days. Similarly the number of streptococci increased from 2.80 to 4.79 during the same period, although when expressed as a percentage of the total c.f.u., the proportions decreased from 34.9 per cent at 1 day to 6.9 per cent at 7 days and then remained at that level. The number of micro-aerophilic actinomyces increased throughout the period of plaque accumulation and comprised 15.3 per cent of the total c.f.u. at 28 days. Neisseriae were infrequently isolated from 0.5- and 1-day-old plaque and were not recovered at more than 1 per cent of the total c.f.u. during any period of plaque accumulation. The fastest doubling time (median) of the total c.f.u. was 1.9 h (range 1.3–18.5 h). The rapid development of dental plaque after tooth cleaning emphasizes the importance of regular and meticulous oral hygiene to control the accumulation of potentially period ontopathic and cariogenic bacteria.