Comparative ergonomic evaluation of the hand-pieces of three instrument series for root planning

Mario Migliario, Andrea Melle, Paola Carcieri, Lia Rimondini

Degree Course in Dental Hygiene, “Amedeo Avogadro” University of Eastern Piedmont, Alessandria-Vercelli-Novara, Italy.
Department of Health Sciences, “Amedeo Avogadro” University of Eastern Piedmont, Alessandria-Vercelli-Novara, Italy.

DOI: 10.4236/ojst.2014.42011                

Abstract

Introduction: Musculoskeletal disorders (MSD) are the most frequent cause of disability in the working population, exceeding accidental trauma in frequency. The risk of developing work-related upper limb disorders (WURLDs) is high among dental hygienists and the most frequently affected are elderly subjects and women. Since such disorders can have a negative effect on the working life and on the quality of life, it is of vital importance to put in place preventive measures. Aim: To make a comparative analysis of the hand-pieces of three different manual instruments used for root planning. Materials and Methods: To evaluate the physical characteristics (section, diameter, external surface, weight) of the hand-pieces of three series of instruments for root planning, twenty-nine dental hygienists students were videoed while working clinically. They were also interviewed using a specific questionnaire to determine subjective preferences in terms of perceived efficacy, safety, comfort and general acceptability of the hand-piece used. Results: Lightness, full-cylindrical section with larger-diameter ends, and coating with anti-slip silicone are the most appreciated characteristics of a hand-piece. Conclusions: Ergonomic analyses of manual instruments are not frequent in the dental field, and the literature reports no guidelines to guide selection of the type of hand-piece of manual instruments. The data gathered may help manufacturers in designing new manual instruments, and guiding professionals in their selection.

Keywords

Dental Hygienist; Instrumentation; Professional Practice; Periodontal Instruments

2. MATERIALS AND METHODS

2.1. Study Design

This comparative study was approved by the Local InterHospital Ethics Committee (EC Prot. 57/10). It evaluated three different types of hand-piece of manual instruments used for root planning (Gracey curettes) selected from among those in most widespread use in day-o-day clinical practice.

2.2. Materials and Methods

The hand-pieces were subdivided into three classes, considering shape of section (octagonal, uniformly cylindrical, non-uniformly cylindrical), external surface (knurled, satin-finish, coated with anti-slip material), weight and diameter (Figure 1). Hand-pieces classified as A are made of steel with octagonal section, diameter 6 mm, external surface knurled, weight 17.68 g; type B are made of steel, cylindrical section, uniform diameter of 10 mm, external surface satin-finish, knurled at either end, weight 21.36 g; type C have non-uniform cylindrical secon with diameter at either end of 11.5 mm and 8.5 mm in the central part, surface covered with anti-slip silicone in the central part and knurled at either end, weight 15.89 g.

2.3. Subjects

Twenty-nine students of our Dental Hygiene School were enrolled in the study and, informed of the goals and study design, all gave their informed consent as per Italian Law no. 675 dated 31/12/1996 and subsequent modifications.

2.4. Procedure

Each student has used, for ten root-planning continually during clinical work, a series of Gracey curettes, one per type of hand-piece to be tested, distinguished with the letters A/B/C.

At completion of the period of use of the instruments provided, each student filled in a questionnaire (Table 1) with questions investigating a series of parameters related to the perceived efficacy, safety and comfort during use. The replies were formulated on a 5-level ordinal scale of evaluation (from 0 = very poor to 4 = high); higher scores indicated a higher value of the parameter investigated.

The scores assigned to questions 2-5, 7, 9-12, 14-17, 19-24 have contributed to determine the degree of satisfaction for the section, those that refer to questions 3-6

Figure 1. Physical characteristics of the three hand-pieces analyzed and satisfaction expressed (from 0 = minimum to 4 = maximum) by the hygienists.

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Hoe, V.C.W., Urquhart, D.M., Kelsall, H.L. and Sim, M.R. (2012) Ergonomic design and training for preventing work-related musculoskeletal disorders of the upper limb and neck in adults (Review). Cochrane Database of Systematic Reviews, 15, CD008570.
[2]	Conrad, J.C., Osborn, J.B., Conrad, K.J. and Jetzer, T.C. (1990) Peripheral nerve dysfunction in practicing dental hygienists. Journal of Dental Hygiene, 64, 382-387.
[3]	Rice, V.J., Nindl, B. and Pentikis, J.S. (1996) Dental workers, musculoskeletal cumulative trauma, and carpal tunnel syndrome: Who is at risk? A pilot study. International Journal of Occupational Safety and Ergonomics, 2, 218-233.
[4]	Michalak-Turcotte, C. (2000) Controlling dental hygiene work-related musculoskeletal disorders: The ergonomic process. Journal of Dental Hygiene, 74, 41-48.
[5]	Lalumandier, J.A. and McPhee, S.D. (2001) Prevalence and risk factors of hand problems and carpal tunnel syndrome among dental hygienists. Journal of Dental Hygiene, 75, 130-134.
[6]	Anton, D., Rosecrance, J., Merlino, L. and Cook, T. (2002) Prevalence of musculoskeletal symptoms and carpal tunnel syndrome among dental hygienists. American Journal of Industrial Medicine, 42, 248-257. http://dx.doi.org/10.1002/ajim.10110
[7]	Werner, R.A., Hamann, C., Franzblau, A. and Rodgers, P.A. (2002) Prevalence of carpal tunnel syndrome and upper extremity tendinitis among dental hygienists. Journal of Dental Hygiene, 76, 126-132.
[8]	Valachi, B. and Valachi, K. (2003) Mechanisms leading to musculoskeletal disorders in dentistry. Journal of the American Dental Association, 134, 1344-1350. http://dx.doi.org/10.14219/jada.archive.2003.0048
[9]	Treaster, D.E. and Burr, D. (2004) Gender differences in prevalence of upper extremity musculo-skeletal disorders. Ergonomics, 47, 495-526. http://dx.doi.org/10.1080/00140130310001638171
[10]	Sartorio, F., Vercelli, S., Ferriero, G., D’Angelo, F., Migliario, M. and Franchignoni, M. (2005) Work-related musculoskeletal diseases in dental professionals. 1. Prevalence and risk factors. Giornale Italiano di Medicina del Lavoro ed Ergonomia, 27, 165-169.
[11]	Hayes, M., Cockrell, D. and Smith, D.R. (2009) A systematic review of musculoskeletal disorders among dental professionals. International Journal of Dental Hygiene, 7, 159-165. http://dx.doi.org/10.1111/j.1601-5037.2009.00395.x
[12]	Hayes, M.J., Smith, D.R. and Cockrell, D. (2010) An international review of musculoskeletal disorders in the dental hygiene profession. International Dental Journal, 60, 343-352.
[13]	Morse, T., Bruneau, H. and Dussetschleger, J. (2010) Musculoskeletal disorders of the neck and shoulder in the dental professions. Work, 35, 419-429.
[14]	Gerwatowski, L.J., McFall, D.B. and Stach, D.J. (1992) Carpal tunnel syndrome. Risk factors and preventive strategies for the dental hygienist. Journal of Dental Hygiene, 66, 89-94.
[15]	Liskiewicz, S.T. and Kerschbaum, W.E. (1997) Cumulative trauma disorders: An ergonomic approach for prevention. Journal of Dental Hygiene, 71, 162-167.
[16]	Sanders, M.A. and Turcotte, M.C. (2002) Strategies to reduce work-related musculo-skeletal disorders in dental hygienists: Two case studies. Journal of Hand Therapy, 15, 363-374. http://dx.doi.org/10.1016/S0894-1130(02)80008-4
[17]	Valachi, B. and Valachi, K. (2003) Preventing musculoskeletal disorders in clinical dentistry: Strategies to address the mechanisms leading to musculoskeletal disorders. Journal of the American Dental Association, 134, 1604-1612. http://dx.doi.org/10.14219/jada.archive.2003.0106
[18]	Sartorio, F., Franchignoni, F., Ferriero, G., Vercelli, S., Odescalchi, L., Augusti, D. and Migliario, M. (2005) Work-related musculoskeletal disorders in dental professionals. 2. Prevention, ergonomic strategies and therapeutic programs. Giornale Italiano di Medicina del Lavoro ed Ergonomia, 27, 442-448.
[19]	Gupta, S. (2011) Ergonomic applications to dental practice. Indian Journal of Dental Research, 22, 816-822. http://dx.doi.org/10.4103/0970-9290.94677
[20]	Matsuda, S.A. (1999) Instruments and principles for instrumentation. In Wilkins, E.M., Ed., Clinical Practice of Dental Hygienist, 10th Edition, Lippincott Williams & Wilkins Inc., Baltimore.
[21]	Dong, H., Barr, A., Loomer, P., Laroche, C., Young, E. and Rempel, D. (2006) The effects of periodontal instrument handle design on hand muscle load and pinch force. Journal of the American Dental Association, 137, 1123-1130. http://dx.doi.org/10.14219/jada.archive.2006.0352
[22]	Dong, H., Loomer, P., Barr, A., Laroche, C., Young, E. and Rempel, D. (2007) The effect of tool handle shape on hand muscle load and pinch force in a simulated dental scaling task. Applied Ergonomics, 38, 525-531. http://dx.doi.org/10.1016/j.apergo.2006.09.002
[23]	Meador, H.L. (1993) The Biocentric technique: A guide to avoiding occupational pain. Journal of Dental Hygiene, 67, 38-51.
[24]	Simmer-Beck, M. and Branson, B.G. (2010) An evidence-based review of ergonomic features of dental hygiene instruments. Work, 35, 477-485.
[25]	Migliario, M., Franchignoni, M., Soldati, L., Melle, A., Carcieri, P. and Ferriero, G. (2012) Ergonomic analysis of the handle of manual instruments for dental hygiene. Giornale Italiano di Medicina del Lavoro ed Ergonomia, 34, 202-206.
[26]	Rempel, D., Lee, D.L., Dawson, K. and Loomer, P. (2012) The effects of periodontal curette handle weight and diameter on arm pain: A four-month randomized controlled trial. Journal of the American Dental Association, 143, 1105-1113. http://dx.doi.org/10.14219/jada.archive.2012.0041
[27]	Rossi, J., Berton, E., Grélot, L. and Barla, C. (2012) Characterisation of forces exerted by the entire hand during the power grip: Effect of the handle diameter. Ergonomics, 55, 682-692. http://dx.doi.org/10.1080/00140139.2011.652195