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Inside Dentistry
August 2015
Volume 11, Issue 8

Advances in Hard Tissue Preparation

Gerard Kugel, DMD, MS, PhD

The preparation of hard tissue is fundamental to the practice of general dentists. The right tools for this purpose can noticeably enhance the efficiency and accuracy of the operator’s workflow.

Early handpieces designed for this task were slow and laborious for the dentist. In addition to lacking power, they were heavy and bulky, resulting in poor ergonomics that often led to workplace fatigue and eventual injury. The noise of these devices was often bothersome to patients, leading to phobia of the dentist’s office.

Through the years, handpieces have been slowly redesigned to be the highly efficient and sophisticated tools they are today. Traditional high-speed air-driven handpieces employ a turbine to rotate the rotary cutting instrument between 250,000 and 420,000 rpm. Air-driven handpieces are appreciated in dental practices for their lightweight and slim designs, in addition to generally low repair and startup expenses. The bur can slow under heavy loads, however, reducing cutting ability. Another disadvantage of traditional air-driven handpieces are the bearings, which may cause the “chatter” that patients dislike.

Electric handpieces operate at a minimum of 20 rpm and can reach up to 200,000 rpm, depending on the type. With the attachments available for these devices, a single electric handpiece can be employed for both high-speed and low-speed procedures. The cutting bur is connected through gears in the head of the handpiece to a central drive shaft that is turned by the motor. The absence of air means these options are quieter, and the chance of air embolism in a surgical site is eliminated. Although electric handpieces have traditionally been heavier and bulkier than their air-driven counterparts, newer models have been streamlined to reduce weight and drag and improve ergonomics. Startup costs may be greater and repairs may be more expensive for these types of handpieces.

For many clinicians, lasers are becoming an attractive option for hard-tissue ablasion. Available in a variety of types that use different wavelengths, lasers can remove dental hard tissue with minimal vibration and noise, which can be a major advantage for patient comfort. The precision of today’s dental lasers also has the potential to substantially reduce the amount of tissue removed during cavity preparations. One concern surrounding the use of lasers is a potential increase in pulpal temperature during hard-tissue ablation. Although it has been found that lasers do raise pulpal temperature when compared to handpieces, they do so within an acceptable threshold of 5.5°C, and therefore do not lead to a loss of pulpal vitality.1

When choosing equipment for the removal of hard tissue, clinicians consider a variety of factors, including cost, noise, power, size, weight, and other factors. Finding the right solution provides great benefits for the dental team and patients.

About the Author

Gerard Kugel, DMD, MS, PhD
Professor, Prosthodontics & Operative Dentistry
Associate Dean for Research
Tufts University School of Dental Medicine
Boston, Massachusetts


1. Penn C, Beninati C, Mariano A, et al. Thermal effects on pulp due to handpiece and laser useage. Compend Contin Educ Dent. 2014;35(10):e41-e44.

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