Coronal Polishing: The evolution of handpieces offers a new spin on dental hygiene services

By Marianne Dryer, RDH, MEd

Coronal polishing has undergone critical examination within the dental hygiene profession - for many good reasons. Our thought processes have evolved as clinicians on the procedure, particularly among those in dental hygiene education. Educators are striving to produce graduates who are competent in coronal polishing, meticulous in performing that process, and knowledgeable of options.

Hygienists who graduated 30-plus years ago remember the process of polishing and disclosing, then re-polishing and re-disclosing. We were terrified that there may be an area we missed, that our instructors would surely find it with their 3D vision! Were we “over-polishing”? Perhaps. But our intentions were aimed toward the goal of having patients leaving the appointment plaque-free. If we consider this along with the handpieces we were using, we may well have been too aggressive. As we have learned with our scaling approach via the evidence over the years, aggressive removal techniques were not indicated and, in fact, could do harm.

As a result of the research demonstrating that polishing may damage the tooth surface, the idea of selective polishing was born. This theory, which was introduced in the late 1970s, asserts that polishing should be performed only on teeth with extrinsic stain. The selective polishing theory was initially supported by research that showed polishing could abrade the tooth structure. However, the validity of this research has been questioned due to sample sizes, uncontrolled variables, and other issues. No scientific evidence demonstrates how much enamel (if any)is removed during polishing procedures. It was hypothesized that, as a result of this research, thorough brushing and flossing at home can remove dental plaque/biofilm as effectively as polishing (Waring & Horn 1988).

The ADHA responded with a position paper stating that polishing of coronal surfaces without stain provides no additional benefit to the patient (ADHA,1998). In essence, polishing was utilized for stain removal. If there did not appear to be a therapeutic need to polish, clinicians were advised not to.

Our patients’ expectations, and their overall satisfaction of treatment as well, was loudly heard when this new approach initiated. According to the process of evidence-based dentistry, the third aspect of practicing this way is patients’ needs and preferences.

A study done in 2011 by Pence et al. demonstrated that use of parameters determined by Christensen back in 1987 did not result in significant removal of enamel. Christensen determined from a nationwide sample of 29 clinicians (20 dental hygienists, three general dentists, three specialists, and three dental assistants) that 2,500 rpm, 150 grams of pressure, and a five-second duration were the average polishing parameters utilized in practice. Pence found that the initial study documenting enamel loss from polishing used methods not acceptable for clinical use, while results from other studies are inconsistent. (Christensen and Bangerter, 1984, 1987) (Pence et al, 2011)

Dental professionals now look at selective polishing from the aspect of selecting what we are using as a polishing agent for the individual patient’s needs. We should also consider selecting equipment and proper techniques to help us maintain those effective polishing parameters.

Today’s polishing devices are now used for a much wider range of activities, including biofilm disruption prior to ultrasonic scaling, application of desensitizing pastes, and preparing teeth for sealants. In addition, more hygienists are providing services in settings outside of the traditional dental office - long-term care facilities, schools, mobile units, remote mission facilities, homebound patient residencies, and locations without traditional air and water hookups.

Considerations for Dental Hygiene Handpieces

Musculoskeletal disorders (MSD) are a significant problem for the dental profession. A high prevalence (64% to 96%) of dental professionals report having musculoskeletal pain or discomfort in a 12-month period, indicating that much of these MSDs are work related (Marshall et al, 1996).

Selecting a hygiene-specific handpiece with a comfortable, ergonomic design is important to the clinician, providing features that enhance the polishing procedure. Handpiece specifications currently advocated by ergonomists include a light weight and adequate balance that allows for a relaxed grip, as well as a nonslip surface for ease of control. It is also highly recommended that the handpiece have a larger diameter to increase the pinch width of the operator, which would reduce the possibility of cumulative trauma disorders (Akesson et al, 1999).

The recognition of musculoskeletal disorders began to emerge in the 1980s, and the ergonomic stresses from polishing started to become apparent. Carpal tunnel syndrome, thoracic outlet syndrome, and various neuromuscular neck and back conditions were attributed to the weight, wrist alignment, and drag of the heavier handpieces used by hygienists.

Handpiece design for the dental hygienist centered on improving ergonomic conditions. The Midwest RDH handpiece (introduced in 1996) changed our thoughts about polishing handpieces. The new design had a much wider diameter grip allowing for a more relaxed grasp, and the weight was dramatically reduced.

The design of the handpiece can influence the speed at which the clinician operates it. Hygienists using a low-speed handpiece designed for dental procedures can operate at up to 8,000 rpm, significantly higher than needed for a polishing procedure.

Slow-speed hygiene handpieces specifically designed for the polishing procedure are available that operate at a more appropriate speed range (maximum of 3,000 to 4,500 rpm), making it easier for the clinician to maintain the lowest speed possible while achieving effective results.

Combined, speed and pressure increase the rate of abrasion and create heat, which can initiate or worsen dentinal hypersensitivity, and it should be kept to a minimum. When speed is increased, pressure should be decreased accordingly.

Cordless Handpieces

The introduction of cordless handpieces was the next step in ergonomic improvement for hygienists. The challenges have been battery life, power sufficiency, and infection control considerations. As the profession continues to evolve, many hygienists are entering the public health arena. When delivering hygiene services in a variety of clinical settings, the cordless innovation has been a valuable asset in these environments.

Cordless handpieces are noticeably quieter than air driven ones, which is attractive for the patient but also protective for the clinician. Quieter does not directly coincide with power levels, but some clinicians felt the speed or performance of these cordless designs were lacking in delivery. It is important for the dental hygienist to be efficient and effective in the polishing procedure. But they should be mindful of effective polishing parameters and the iatrogenic problems that can occur from using excessive speed and pressure.

Pedal-Free Cordless Handpieces

The evolution of hygiene handpieces that allow for operation without a foot pedal or cording has really created true freedom for the hygienist. We can all relate to the frequent frustration of finding the foot pedal, moving the foot pedal, and incorporating this into the flow of the polishing procedure. This may have become second nature to us, but consider the benefits of eliminating this distraction. The elimination of a foot pedal allows the clinician to move more fluidly and concentrate solely on the polishing process.

Those of us that utilize cruise control in our vehicles know the feeling of relaxation, once we remove our foot from the pedal and simply steer the car with our hands. The benefits are clear, and the technology is here.

The Nupro Freedom Cordless Prophy System with SmartMode Technology (Dentsply Sirona) provides clinicians with an innovative method of controlling the speed and the power of the prophy cup. The handpiece is intuitive, allowing the clinician to fully control the handpiece function solely in their hand, without pushing buttons or reaching for foot pedals.

The speed of the rubber cup increases intuitively as you increase the amount of contact pressure being applied against a tooth surface. The rpm speed will subsequently decrease as less pressure is applied.

If the clinician prefers it, the iStar Cordless Prophy System (DentalEZ) offers the option of also being operated without a foot pedal. This is initiated by pushing a button on the handpiece below the disposable prophy angle for initiation and speed adjustments.

These innovative products may require a certain learning curve for technique adaptations. The fluidity of the Nupro Freedom System provides uninterrupted polishing with its intuitive responsive design, while the iStar offers more manual interruption of the cup rotation.

Battery life of both models claim a three-hour constant run charge, which equates to a full day of patients providing an approximate three-minute polish for 10 patients. The Nupro Freedom may be quick charged in 15 minutes, allowing for extended use prior to performing a complete charge.

The ability to move through the polishing procedure more fluidly is an obvious benefit, particularly to the pediatric patient. The frequent removal for adjustments for the pedal function and seating accommodation can be disruptive and add unnecessary time to the procedure.

SmartMode Technology provides further fluidity by its intuitive process of speed adaptation according to the clinician’s need for increased rotation and power. With increased use, the technique adaptation is accomplished, and true freedom is the end result.

Infection Prevention

Some cordless handpieces may also provide additional benefits with compliance to infection prevention protocols. In 2016, the Centers for Disease Control and Prevention (CDC), released its Summary of Infection Prevention Practices in the Dental Setting, reinforcing that dental handpieces should always be heat sterilized between patients, and not high level or surface disinfected.

The acceptable methods of sterilization include chemical vapor sterilizers, dry heat, and autoclaves. Ethylene oxide gas is not recommended for dental handpieces (CDC.gov). The issue of heat sterilization of handpieces for every patient every time equates to high cost, heavy usage on the handpiece and turbines, and increased staff time.

The Nupro Freedom cordless handpiece allows clinicians to autoclave the removable sheath and provide each patient with a sterilized handpiece each time. Complying with the CDC guidelines for reprocessing dental handpieces is a major part of infection prevention in the office. The Nupro Freedom Prophy System allows you to do that at a fraction of the cost.

Polishing Agents

Patients often consider polishing as the hallmark of the prophylaxis appointment, often critical to patient satisfaction. Polishing provides some patients with an improved esthetic appearance, and they are convinced that their teeth have been thoroughly cleaned. Coronal polishing choices should be individual to the patient while meeting their needs and expectations.

Clinicians must be aware of current evidence-based research regarding biofilm and stain removal. For example, polishing over demineralized areas will result in three times more surface enamel being removed than intact enamel. Polishing agents must be carefully considered so that no harm is done to the enamel or cementum by aggressive technique or materials. If the enamel surface is scratched as an example, it then becomes a reservoir for harboring bacteria.

Factors that will affect abrading the tooth surface during polishing include pressure, speed, quality of paste, and shape, size, and hardness of the abrasive particles. Cleaning and polishing abrasive agents incorporated into the prophylaxis paste contain different shapes and edges that scratch the surface of the enamel. The grit or size is the main factor. (Dondiego, 2012). There are a variety of prophy paste products that provide therapeutic benefits such as potential for remineralization and relief of hypersensitivity.

Coronal polishing is part of the dental hygiene process of care for many of our patients. The need for clinicians to be well informed of the evidence regarding clinical outcomes, therapeutic polishing agents and newer technologies in handpiece choices is paramount. The experience should be a positive, beneficial one for the patient, as well as for the clinician. Choose wisely when considering your next hygiene handpiece. Consider the potential freedom from cords, foot pedals and CDC compliance with handpiece sterilization.

We are evolving in our profession to meet the needs of our communities. Conversely, we must advocate to meet our own clinical needs and adopt technologies and equipment that will deliver more effortless, stress free performance. Career longevity can frequently be interpreted by musculoskeletal conditions. Be mindful to care for your body and implement changes that will reduce stress in the fast paced world of dentistry and allow you to focus on what is most important, your patient! RDH

Marianne Dryer, RDH, MEd, is a Global Clinical Education Curriculum Developer for Dentsply Sirona. Her focus is on ultrasonic instrumentation, local anesthesia, and radiology technique. Her experience in dentistry spans over 30 years as a clinician and an educator. She is a graduate of Forsyth School for Dental Hygienists, Old Dominion University and received her master’s in education from St Joseph’s College of Maine. Marianne was the first-year coordinator at Collin College in Dallas, Texas, for six years where she was selected for the Outstanding Faculty Award and was nominated for the Advisor of the Year. She has been a faculty member at Cape Cod Community College since 2007. Marianne is also a periodontal instrumentation Instructor for DH Methods of Education, Inc., an educational program for dental and dental hygiene faculty.

References

1. Akesson I, Johnsson B, Rylander L, Moritz U, Skerfving S. Musculoskeletal disorders among female dental personnel - clinical examination and a 5-year follow-up study of symptoms. Int Arch Occup Environ Health. 1999;72(6):395-403.
2. Christensen RP, Bangerter VW. Determination of rpm time and load used in oral prophylaxis polishing in vivo. J Dent Res 1984 Dec; 63(12): 1376-82.
3. Christensen RP, Bangerter VW. Immediate and long-term in vivo effects of polishing on enamel and dentin. J Prosthet Dent. 1987;57:150-160.
4. Dondiego L. Factors in Coronal Polishing Evidence-based research prompts new approaches to a standard procedure. May/Jun 2012 Volume 8, Issue 3.
5. Marshall ED, Duncombe LM, Robinson RQ, Kilbreath SL. Musculoskeletal symptoms in New South Wales dentists. Aust Dent J. 1996;42(4):240-246.
6. Murphy DC. Ergonomics and the Dental Care Worker. Washington DC: American Public Health Association; 1998.
7. Pence et al. Repetitive coronal polishing yields minimal enamel loss. J Dent Hyg Fall 2011; 85(4): 348-357.
8. Waring MB, Horn ML, Ames LL, Williams NJ, Lyne SM. Plaque reaccumulation following engine polishing or toothbrushing: a 90-day clinical trial. Dent Hyg (Chic). 1988 Jun;62(6):282-5.

Website references

1. 2003 CDC Guidelines: Handpiece and single use device sterilization-cdc.gov/mmwr/preview/mmwrhtml/rr5217a1.htm
2. 2016 CDC Summary of Infection Prevention Practices in the Dental Setting - cdc.gov/oralhealth/infectioncontrol/guidelines/
3. American Dental Hygienists’ Association Position on Polishing Procedures, 1998 - adha.org