Dental Plaque

Dental plaque is a structured, sticky biofilm of bacteria in an extracellular matrix of salivary proteins and bacterial polysaccharides that forms on tooth surfaces, restorations and appliances and cannot be removed by rinsing. It is the principal cause of dental caries and gingivitis, and the starting point of periodontitis.

• Formation: within minutes of cleaning, salivary proteins form the acquired pellicle; early colonisers (Streptococcus and Actinomyces species) attach within hours; fusobacteria bridge to late colonisers (Porphyromonas gingivalis, Tannerella forsythia and spirochaetes), which mature over 2 to 14 days.
• Supragingival plaque (above the gum margin) produces acid from sugars and causes caries; subgingival plaque (below the margin) causes gingival inflammation and periodontal destruction.
• Plaque mineralises into calculus within 2 to 14 days in some people.
• Factors that increase plaque: poor oral hygiene, frequent sugar intake, dry mouth, crowded teeth, overhanging restorations, orthodontic appliances and dentures, smoking, diabetes and some medicines.

• Soft, whitish or yellowish film at the gum margin and between teeth that wipes off with a swab; invisible when thin until stained or disclosed.
• Bad taste, bad breath, and furry teeth on waking.
• Early signs of the resulting disease: red, swollen gums that bleed on brushing or probing (gingivitis), white spot decalcification at the gum margin, and caries.
• Examination: use disclosing tablets or solution (erythrosine) to colour plaque; record a plaque score (percentage of surfaces with plaque; under 20 percent is good control); look for gingival bleeding, calculus, caries, restorations and appliances.

• Clinical examination of teeth and gums in good light with a mirror and probe.
• Plaque and bleeding scores at baseline and follow up.
• Periodontal screening (basic periodontal examination of each sextant) to detect pockets of 4 mm or more, which need dental referral.
• Check risk factors: diet diary (frequency of sugary snacks and drinks), saliva flow, smoking, diabetes control (HbA1c), medicines causing dry mouth.
• Differentials: food debris, materia alba (soft deposit without structure), extrinsic stain, calculus, candidiasis, and white spot lesions.

Mechanical plaque control (the foundation)

• Brush twice daily (morning and last thing at night) for 2 minutes with a soft-to-medium brush using a modified Bass technique, angling bristles 45 degrees to the gum margin; replace the brush every 3 months. Powered (oscillating rotating) brushes remove more plaque than manual brushes.
• Clean between teeth once daily: interdental brushes (choose the largest size that fits without force; 0.4 to 1.5 mm) are most effective; use floss or tape for tight contacts; use water flossers if manual dexterity is poor.
• Brush the tongue; clean dentures daily out of the mouth and soak overnight in a denture cleaner.

Fluoride toothpaste

• Adults: 1350 to 1500 ppm fluoride; spit out the excess and do not rinse with water afterwards; people at high caries risk: 2800 to 5000 ppm fluoride on prescription from a dentist.
• Children: under 3 years, a smear of 1000 ppm toothpaste twice daily; 3 to 6 years, a pea sized amount of 1000 to 1450 ppm; 7 years and over, 1350 to 1500 ppm; supervise brushing until about age 8.

Chemical plaque control (as an adjunct)

• Chlorhexidine gluconate 0.2 percent mouthwash 10 mL for 1 minute twice daily, or 0.12 percent 15 mL, for 2 to 4 weeks at most (for example after periodontal treatment or in people unable to brush); causes brown tooth staining, taste disturbance and, rarely, mucosal irritation; use at a different time from fluoride toothpaste (at least 30 minutes later) because toothpaste inactivates it.
• Cetylpyridinium chloride 0.05 to 0.07 percent or essential oil rinses twice daily for long term use with fewer side effects.
• Fluoride mouthwash 0.05 percent sodium fluoride daily at a time separate from brushing for people with caries risk.

Diet

• Limit free sugars to under 5 percent of energy and sugar containing food and drinks to mealtimes (no more than 4 sugar exposures daily); use water between meals; use sugar free gum for 10 minutes after meals.

Professional care

• Scaling and polishing every 6 to 24 months according to risk; fluoride varnish 22,600 ppm (5 percent sodium fluoride) twice yearly in children and adults at high caries risk; fissure sealants on permanent molars in children.
• Fix plaque retentive factors: overhangs, ill fitting dentures, crowded teeth.

Follow up

• Reassess plaque score and gingival bleeding at 2 to 4 weeks; refer to a dentist at least every 6 to 24 months, sooner for bleeding gums that persist, mobile teeth, or pocketing.