IJSRD - International Journal for Scientific Research & Development| Vol. 5, Issue 05, 2017 | ISSN (online): 2321-0613 All rights reserved by www.ijsrd.com 373 Ergonomic Design of Dental Scaling Hand Tools to Alleviate the Prevalence of Carpal Tunnel Syndrome in Dental Practitioners Vibha Bhatia PG Student Department of Industrial & Product Design PEC University of Technology, Chandigarh India Abstract— Ergonomics plays a major role in dentistry. This is due to the type of work done by dentists and the duration of the work done. The dental practitioners are mostly affected by the musculoskeletal disorders (MSDs) after the particular time span. MSDs usually occur due to the repetitive nature of work. One of the MSD which is quite common is Carpal Tunnel Syndrome. The prevalence of Carpal Tunnel Syndrome is common among the workers who perform the job using their hands, wrists, fingers or upper extremity body parts. All over the world, studies have shown the increase in the occurrence of the Carpal Tunnel Syndrome in the dentists. This disorder has by and large affected most of the dental practitioners and their work leading to the decline in their efficiency of work and affecting their lives badly. Although there are several methods by adopting which we can reduce the prevalence of CTS in dentists but in this review we will focus on the Dental hand tool design which are being used by dentists such as manual scaling hand tools or scalars. Scaling tool has been chosen as the parameter because scaling is often the repetitive task and is usually performed by most of the dentists for longer durations. Several studies have been done on the parameters affecting the scaling tool handle design which can reduce the muscle forces exerted by the dentists. Grip of the tool is also the parameter which determines the load on the muscles of fingers, hands and wrists. Lesser loads on fingers and hands are often taken as the safe parameter for designing hand tools. The loads and forces on muscles have been evaluated by using Electromyography techniques in most of the studies. Key words: MSDs, CTS, Ergonomics, Scaling, Electromyography, Muscle Loads, Pinch Force I. INTRODUCTION With time human hand has also evolved and is capable of performing various important functions of day to day life. These include gripping which can be further classified into many types like power, pinch, and precision and so on. For holding larger objects power grips are found to be more suitable and for holding smaller objects pinch grips. For doing the work with high accuracy, the precision grip plays a role. The role of the thumb is to apply the force opposite to the force exerted by fingers to hold on the tool or object. Muscular structure of hand, hand shape and size, neurological control by hands determines how strong is the grip made of the fingers and thumb. Biomechanical aspect of hand anatomy plays an important role to the determination of the grip strength. In last few decades, many studies have been done on the hand grips which act as a function in assessing the muscle performances in rehabilitation, orthopedics and applied ergonomics. If the task is performed repetitively, it may become the reason of the occurrence of Musculoskeletal Disorders like carpal tunnel syndrome in hands and wrists. Dental scaling is also a repetitive task in which the dentist pulls of the deposits of tartar from the tooth gingiva repetitively till the deposit pockets are clean. It requires an ample amount of the hand muscle force to scrap off the tartar and involves the upward pulling motion with hand and fingers. The periodontal tool is pulled up leading to forearm supination, flexion of fingers in opposition to the thumb. Relevant dental work place design, work study and dental instrument design that require continuous work and incessant use of fingers ,hands and wrist may help in reducing upper extremity disorders due to work. This enhances the need to find out the muscle forces and loads while performing these tasks and the parameters affecting their values in order to get the best possible results out of it. II. TYPES OF HAND GRIPS Two main ways in which grips can be categorized as are Power grips and Pinch grips .Hand grips have been categorized differently over the period of time. In the study [1], hand grips were categorized as: power grip, pinch grip, external precision grip, ulnar precision grip, and other power grips. A. Power Grips The thumb and the fingers overlap in the power grips. The upper extremity muscles are responsible for the movements and not the hand muscles. It is impossible to do precision works using power grips. The handle shape is responsible for the position that the fingers take during power grip. Fig.1 represents the Power Grip while holding a handle. Fig. 1: Power Grip B. Pinch Grips Fig. 2: Pinch Grip