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Development of dental plaque on the incisor teeth of monkeys (Macaca fascicularis)
J R Radford1, D Beighton, F House
1Hunterian Dental Research Unit, London Hospital Medical College, UK.
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 (log10) 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 periodontopathic and cariogenic bacteria.
Insights
Dental plaque rapidly accumulates after cleaning, highlighting the need for consistent oral hygiene. Bacterial counts increase significantly over 28 days, with shifts in microbial composition.
Area of Science:
- Microbiology
- Dental Science
- Oral Health
Background:
- Bacterial plaque accumulation is a dynamic process on tooth surfaces.
- Understanding plaque development is crucial for preventing oral diseases.
- The microbial composition of plaque changes over time.
Purpose of the Study:
- To investigate the quantitative and compositional changes in bacterial plaque over 28 days.
- To determine the growth rate of dental plaque in vivo.
- To correlate plaque age with specific bacterial populations.
Main Methods:
- Dental plaque was collected from central incisors of 15 cynomolgus monkeys at various time points (0.5 to 28 days).
- Sampling was performed using custom-made acrylic blocks with metal wells.
- Total colony-forming units (CFUs) and specific bacterial groups (Streptococci, Actinomyces, Neisseriae) were quantified.
Main Results:
- Total CFUs increased significantly from log10 3.40 to 6.02 over 28 days.
- Streptococci numbers increased, but their proportion decreased over time.
- Micro-aerophilic Actinomyces increased, comprising 15.3% of total CFUs at 28 days.
- Neisseriae were rarely found in early plaque and remained <1% of total CFUs.
Conclusions:
- Rapid bacterial proliferation occurs in dental plaque, with a median doubling time of 1.9 hours.
- The microbial landscape of plaque evolves significantly within 28 days.
- Effective oral hygiene practices are essential to manage plaque accumulation and mitigate risks of periodontitis and caries.