Instrumentation for periodontal therapy

Periodontal therapy involves the removal of calculus and biofilm. A variety of instruments are available to us for this. In recent years there has been much talk of using slimmer ultrasonic tips to debride sub-gingivally.

Ultrasonic describes a non-audible range of acoustical vibrations that are a unit of frequency referred to as cycles per second (CPS) or hertz (Hz). Electrical energy is converted into mechanical energy in the range of 18,000 to 50,000 vibrations per second.

Sonic technology describes instruments that convert electrical energy in the range of 3,000 to 8,000 vibrations per second. Basically sonic means ‘less fast’ than ultrasonic. Sonic scalers vibrate in a circular motion. In most models of scaler the amplitude of the vibraton of the tip can be modified and reproduced accordingly. Calculus is removed by a ‘hammering’ action.

Magnetostrictive or piezoelectric?

Magnetostrictive inserts have a ‘stack’ attached to a working tip or insert. Vibrations are generated through a stack of metal strips. Depending on the type of instrument, the vibrations range from 20 to more than 45kHz, making the instrument tip vibrate in a circular or ellipsoidal pattern.

Piezoelectric units do not have removable inserts. The ‘stack’ in this case is called a ‘transducer’. This comprises ceramic crystals that reside in a permananently sealed handpiece. The tip is threaded into the handpiece of the unit with a custom wrench.

Powered instrumentation versus hand instrumentation

We adjust our techniques and instruments specifically to each patient’s individual needs. Our main aim is adequate instrumentation with minimal substance loss. Repetitive or maintenance therapy can commonly cause damage and over a period of time cause deeper pockets.

Petersilka et al (2002) demonstrated that ultrasonic scalers reduce the sub-gingival biofilm as efficiently as hand instruments. Various reviews clearly state that powered instruments can reduce treatment time dramatically, compared with hand instruments. Overall, research shows a variation of smoother root surfaces with either hand or powered instruments. Depending on the study, it has also been noted that root texture is not significant for healing. However, with maximum instrumentation depths, slimmer ultrasonics seem to produce better results.

With tips being smaller than a hand instrument blade we can gain better access into deep, narrow sites. Line angle pockets are virtually impossible to debride with curettes and failure to reach the base of the pocket is common. The fine tip provides greater access and ease for the operator.

Ultrasonic scalers are ideal for removing the lightest film of plaque or the heaviest deposits of stain and calculus. Although there may be less tactile sensitivity, a slim-line tip can detect calculus deposits and roughness. Calculus removal from within furcations has proven more efficient with ultrasonic and sonic scalers. Over half of furcations are narrower than an average Gracey curette. With the whole tip of an ultrasonic working as a cutting edge, there is no difficulty choosing the appropriate scaling direction, as with a curette.

The mechanical action of the tip removes calculus and biofilm, and the coolant then flushes debris away. This micro-streaming result may even have an anti-bacterial effect on periodontal pathogens.

Pre-rinsing with an anti-bacterial such as chlorhexidine gluconate is recommended to reduce infective aerosol from disturbed biofilm, blood and saliva, along with high volume aspiration.

Recent research shows periodontal disease to be a bacterial infection and our focus should be on controlling the infection. This involves removing bacteria and its toxic by-products from all sources: the root surface, the pocket space, the pocket wall and the underlying tissues.

Ultrasonic scalers are at the forefront of modern periodontal therapy. Debridement of the full mouth to eliminate infection is being demonstrated, leading to higher quality care for patients.

Mechanical instruments result in more effective therapy with faster patient healing, less working time and stress. I have found that using slim-line tips at half power increases patient comfort, providing a more pleasant experience. As for the hygienist, we read more and more about repetitive strain injury and carpal tunnel syndrome, and since the development of the ultrasonic in the 1950s, the smaller, lighter units assist in reducing operator fatigue.

In summary

The use of mechanical as opposed to hand instruments not only reduces operator fatigue but also aids in periodontal healing. The same amount of time we spend developing our hand instrumentation skills should be spent on developing our ultrasonic scaling expertise. More and more experienced hygienists are providing higher levels of care using mechanical instrumentation.

Our job goes beyond the removal of calculus alone and current concepts challenge us and focus our attention on halting disease and preventing further infection.


Dragoo MR (1992) A clinical evaluation of hand and ultrasonic instruments on subgingival debridement. Int Journal Periodontics Restorative Dentistry 12(4): 310-323

Tunkel J, Heinecke A, Flemmig TF (2002) A systematic review of the efficacy of machine-driven and manual sub-gingival debridement in the treatment or chronic periodontitis. Journal of Clinical Periodontology 29(3): 72-81

Petersilka GJ, Ehmke B, Flemmig TF (2002) Antimicrobial effects of mechanical debridement Periodontal 2000 28(1): 56-71

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