By Dr Li Beng Wong, BDS, MDS (Perio) (Singapore), MRD RCS (Edinburgh), FAMS (Perio)

Prophylaxis is the bread and butter of dental hygiene and therapy. The conventional way of carrying out prophylaxis is effective in preventing periodontal diseases, but not without its shortcomings.

According to the American Academy of Periodontology, dental prophylaxis is defined as the removal of plaque, calculus and stains from the exposed and unexposed surfaces of the teeth by scaling and polishing as a preventive measure for the control of local irritational factors.1 Prophylaxis is an important procedure carried out in patients with no active periodontal disease, gingivitis or those with history of periodontitis but have been treated and currently under maintenance. The importance of regular recalls to reinforce oral hygiene instructions to the patient and timely removal of dental plaque to a level compatible with health is supported by various classic studies and this remains as one of the guiding pillars in our modern philosophy of preventive dentistry.

Currently, a prophylaxis session involves doing a proper dental examination, followed by the assessment and reinforcement of oral hygiene practices. The operator will proceed with ultrasonic scaling indiscriminately for the entire mouth to remove plaque and calculus, followed by polishing using rubber cup with prophylaxis paste or pumice. This has been proven effective in maintaining the periodontal health of the patients. However, there are certain disadvantages. Performing scaling and root planing in sites with less than the “critical probing depth” of 2.9mm has been shown to cause clinical attachment loss.5 Polishing agents used like pumice have a higher Mohs hardness value than tooth structures and restorative materials. Prolonged usage can result in irreversible and iatrogenic removal of enamel, dentin and cementum. In addition, restorative materials can be abraded and roughened and this can cause them to be more plaque retentive in the long term.6 There are also limitations in the ability of rubber cups to access areas like sub-gingival restorative margins, around orthodontic brackets, malaligned teeth and peri-implant regions. With advances in technology, newer and improved devices have been used in the market for plaque removal, one of which is the air polishing system. This article will introduce the concept of Guided Biofilm Therapy and how air polishing systems can be incorporated in prophylaxis treatment for patients.

Concept of Air Polishing

The basic concept for air polishing is nothing new. In fact, it was first introduced in the dental market in 1945 for cavity preparation using aluminium particles.7 Modern air polishing devices use pressurised air and water to deliver a controlled stream of powder in a slurry through a handpiece nozzle. This is directed towards the tooth surface to remove surface stains, dental plaque and other soft deposits. The type of powder used plays an important role in determining its usage. Sodium bicarbonate powder (e.g. EMS Classic Powder) has been used in the market since the 1980s. It is non-toxic and water soluble, although up to 0.8% of silicium oxide or tricalcium phosphate is usually incorporated to enhance hydrophobicity, an important characteristic to sustain powder flow when mixed with water. Its mean particle size ranges from 40-120μm and is commonly used for removal of supragingival stains and plaque from intact enamel surfaces. However, sodium bicarbonate powder should not be used for sub-gingival plaque removal. Experimental results have demonstrated substantial root substance loss when it is directed towards denuded root surfaces. Glycine powder (e.g. EMS Perio Powder, Clinpro Prophypowder, 3M) came into the market during the mid-2000s to address the clinical limitations of using sodium bicarbonate powder. It allows sub-gingival plaque removal while minimising trauma to the root surface and soft tissues. The mean particle size of glycine powder used for air polishing is less than 45 μm, 4 times smaller than conventional sodium bicarbonate particles, which accounts for its lower abrasive nature. Erythritol powder (EMS Plus Powder) was recently launched in 2013 to incorporate the stain removing capability of sodium bicarbonate powder together with the gentle characteristic of glycine powder on both hard and soft tissue. It is being promoted as the powder to be used both supra- and sub-gingivally at the same time. Erythritol is a sugar substitute (polyol) that is commonly used as a food additive. It is currently the air polishing powder with the smallest mean particle size of 14 μm available in the market. Although the impact per particle is extremely low due to its small size, the high powder flow density allows it to effectively remove moderate stains. Numerous studies have been carried out over the years to demonstrate the use of air polishing as a modern reliable treatment modality for biofilm removal and the results have been mostly positive. The following consensus was reached during the 7th Europerio congress:

  1. Air-polishing devices have been shown to be efficacious in removing supraand sub-gingival biofilm and stain;
  2. Indications for the use of air polishing devices have been expanded from supra-gingival air polishing to sub gingival air polishing;
  3. The development of low-abrasive glycine-based powders and devices with sub-gingival nozzles provide better access to sub-gingival and interdental areas; and
  4. Mineralised deposits (calculus) have to be removed by power-driven or hand instruments.

The above consensus statements were also supported by a similar consensus conference on supra- and sub gingival air polishing in America.

Guided Biofilm Therapy

The Guided Biofilm Therapy (GBT) is a new concept of prophylaxis which incorporates the use of air polishing in the treatment regime:

Step 1: Pre-rinse with chlorhexidine mouthwash for 60 seconds before treatment. Full dental examination, involving the charting of periodontal probing depths and bleeding of probing sites.

Step 2: Use of plaque disclosing agent for entire dentition to expose biofilm.

Step 3: Provide individualised oral hygiene instruction for the patient based on the plaque score and distribution. Educate patient on importance of good home care.

Step 4: Removal of the disclosed biofilm, stains and young calculus both supra- and sub-gingival up to 4mm using an air polishing device.

Step 5: Use of depth marked PERIOFLOW® nozzle to remove biofilm on teeth, implants and interdentally up to 9mm, if required.

Step 6: Removal of remaining calculus supra-and subgingivally up to 10mm using ultrasonic scalers. Clean >10 mm pockets with a mini curette.

Step 7: Full mouth check for remaining biofilm and calculus. Re-disclose if required.

Step 8: Scheduling for next appointment.

The GBT concept may have the following advantages over conventional methods of prophylaxis:

  1. The use of plaque disclosing agent allows the operator to determine patient compliance in executing proper oral hygiene practices. It also allows the patient to visualise areas that they may have neglected
  2. The use of an air polishing device can remove the disclosed plaque effectively and safely without causing soft tissue damage compared to conventional rubber cups, especially during subgingival plaque removal.
  3. The removal of plaque using air polishing first before ultrasonic scaling provides better visible access to calculus deposits. Instead of the indiscriminate use of ultrasonic scalers for the entire dentition, the operator can now target the use of ultrasonic scalers on sites with mineralised deposits. This minimises soft tissue damage and clinical attachment loss caused by ultrasonic scaling at sites with shallow pocket depths. From the patient’s perspective, this translates to lesser discomfort and sensitivity experienced during ultrasonic scaling. Overall, treatment time is also reduced.
  4. A second plaque disclosure provides quality control and assurance to the patient and allows the operator to assess if they have done a thorough job.

Conclusion

GBT using air polishing may provide an effective and comfortable prophylaxis experience for patients. More studies can be carried out to evaluate its effectiveness in terms of plaque removal and treatment time as well as comfort level in terms of a self-reported questionnaire in comparison to conventional prophylaxis methods. It may prove to be an invaluable treatment protocol for dental hygienists and therapists to adopt in the day-to-day treatment of patients.

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