Dental Plaque – The Prime Reason for Dental Diseases
Dental plaque is the microbial community that develops as a biofilm on the tooth surface, composed of bacterias and of salivary origin. Plaque that becomes calcified is referred to as calculus or tartar. The vast majority of microorganisms from a range of ecosystems grow on a surface as a biofilm. The pioneer species that form the plaque biofilm include members of the mitis group of streptococci, haemophili and Neisseria species.
- Most microorganisms grow as a biofilm on a surface
- A biofilm describes microorganisms attached to a surface
- The phenotype of microorganisms in a biofilm is different from when they grow in liquid culture
- Microorganisms in biofilms are more tolerant of antimicrobial agents, environmental stresses and the host defenses
Different stages in the formation of dental plaque
- Pellicle forms on a clean tooth surface followed by bacteria being transported passively to the tooth surface where they are held reversibly by weak electrostatic forces of attraction. Attachment becomes irreversible by specific molecular interactions, secondary colonisers attach to primary colonisers and then growth results in biofilm maturation, facilitating interbacterial interactions.
- Adhesion of microorganisms to the conditioned tooth surface is a complex process which involves, initially, weak long range electrostatic attractive forces, followed by a variety of specific, strong and short-range molecular interactions between bacterial adhesins and receptors adsorbed to the surface.
- Fusobacteria act as a bridge between early and late colonising bacteria. If conditions become unfavourable, some cells are able to actively detach, which creates an opportunity for them to colonise other sites.
Predominant groups of bacteria found at distinct sites on the tooth surface
- In the approximal surface of the teeth – Gram-positive and Gram-negative; facultative and obligate anaerobes: Neisseria, streptococcus, actinomyces, prevotella and veillonella
- In the fissures of the teeth – Gram-positive; facultative anaerobes – Streptococcus, actinomyces
- In the gingival crevices – Gram-positive and Gram-negative; facultative and obligate anaerobes: – Streptococcus, actinomyces, eubacterium, fusobacterium, prevotella and treponema
- The microbial composition of biofilms on teeth varies due to change in the local environment. Fissures are influenced by the properties of saliva. The gingival crevice supports the growth of anaerobic bacteria, many of which are Gram negative and proteolytic. GCF has a major influence on the biology of this site. The microbial community of fissures is less diverse than that of approximal sites and the gingival crevice.
Plaque mediated diseases in mouth are –
- Caries
- Periodontal diseases
Approaches for controlling Plaque-Mediated Diseases
- Oral hygiene maintenance
- Scaling and Root planing
- Periodontal surgical treatment
- Fluoride therapy
- Antimicrobial agents like Chlorhexidine
- Replacement therapy, prebiotics and probiotics
Article by Dr. Siri P.B.
