European Journal of Dental Education ISSN 1396-5883
The association between restorative pre-clinical activities and musculoskeletal disorders P. A. Corrocher1, C. D. Presoto2, J. A. D. B. Campos1 and P. P. N. S. Garcia1 1 2
Department of Social Dentistry, Araraquara Dental School, UNESP, Univ Estadual Paulista, Araraquara, Brazil, Department of Restorative Dentistry, Araraquara Dental School, UNESP, Univ Estadual Paulista, Araraquara, Brazil
Keywords occupational hazards; human engineering; dental students; musculoskeletal disorders. Correspondence Patrıcia P. N. S. Garcia Department of Social Dentistry Araraquara Dental School UNESP Univ Estadual Paulista Rua Humait a 1680, Centro Araraquara CEP: 14.801-903, Brazil Tel: +55 16 3301 6405 Fax: +55 16 3301 6343 e-mail: [email protected]
Abstract Objective: To evaluate the risk of development of musculoskeletal disorders in the upper limbs of undergraduate dentistry students during the execution of pre-clinical laboratory activities based on gender, type of dental procedure and area of the mouth under treatment. Methods: Male and female undergraduate students in the second year of the Araraquara Dental School, UNESP, were enrolled in this study. Digital photographs were obtained whilst the subjects performed laboratory activities. The working postures adopted by each student were evaluated using the Rapid Upper Limb Assessment (RULA). The photos were analysed by a calibrated researcher (k = 0.89), and a final risk score was attributed to each analysed procedure (n = 354). Descriptive statistical analyses were performed, and the associations of interest were analysed by the chisquare test (P = 0.05).
Accepted: 5 October 2013 doi: 10.1111/eje.12070
Results: During most of the laboratory procedures performed, the risk of developing musculoskeletal disorders was high (64.7%; – IC95%: 59.7-69.7%), with no significant association between the RULA final score and gender (v2 = 1.100; P = 0.577), type of dental procedure (v2 = 5.447, P = 0.244) and mouth area treated (v2=4.150; P = 0.126). Conclusions: The risk of developing musculoskeletal disorders was high in undergraduate dentistry students; this risk was not related to gender, type of dental procedure and region of the mouth being treated.
Introduction Dentists are predisposed to various occupational diseases due to their work environment (1, 2). Whilst performing dental procedures, they may be required to remain in uncomfortable positions for long periods of time, such as twisting of the spine and neck, bearing increased shoulder load, repetitive movements and prolonged fixed postures, which may have detrimental effects on their health (3, 4). Musculoskeletal disorders include a group of diseases caused by excessive and repetitive daily laborious activities, which can affect the muscles, joints, nerves, blood vessels and tendons (5). When these disorders are related to work, they can be
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characterised by the occurrence of various concomitant symptoms, for example pain, numbness, heaviness and fatigue mainly in the affected body part (6). Musculoskeletal disorders principally affect the upper limbs of a dentist and often result in temporary or permanent work disability (7, 8). A dentist’s work environment has improved in recent years, allowing the professional to work in a sitting posture, to rationalise their work and to adopt ergonomic postures (9, 10). However, despite these advances, dental professionals are at a high risk of developing diseases caused by their working posture (1, 2, 5, 11). To tackle the increasing prevalence of these disorders, prevention techniques must be adopted as early as possible,
ª 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd Eur J Dent Educ 18 (2014) 142–146
Corrocher et al.
preferably when a dentist is still under training at an institution, for example during pre-clinical or laboratory activity (11–14), because postural defects can be more easily identified and corrected during this initial learning phase (1, 15). Thus, the aim of the present study was to assess the risk of development of musculoskeletal disorders in the upper limbs of dentistry students during the execution of pre-clinical laboratory activities, with respect to the gender, procedures performed and mouth area treated.
Materials and methods Sample design This observational study included all second-year undergraduate students of the Araraquara Dental School (UNESP) who agreed to participate in this study. The study was approved by the Ethics Research Committee of the Araraquara Dental School, UNESP (Protocol number 53/10). The working postures adopted by these students whilst they performed pre-clinical activities in the Laboratory of Operative Dentistry were evaluated in this study.
Records of working postures For this study, we obtained digital photographs of the working postures adopted by the enrolled students during the various laboratory procedures linked to the restoration of dental elements (n = 354). The photographs were taken at least 10 min after the activities started, hence allowing the students to become comfortable in their postures. The sequential photographic records for different parts of the body were carried out with the photographer holding the camera close to the eyes at a distance of about 1.5 m from the ground, orthogonally. The photographs were taken by two researchers, previously trained in the pilot study, who were different from the professor in ergonomics. These photographs were evaluated by a researcher after intra-examiner calibration to assess the intra-examiner reliability of the postural assessments; a reproducibility study was conducted within the pilot study. In this study, the researcher examined the postures adopted by the undergraduate students in duplicate whilst performing 50 pre-clinical procedures, with an interval period of 1 week between assessments. The intraexaminer concordance of the risk score for the development of musculoskeletal disorders was estimated using linear-averaging kappa statistics (16) With regard to the value of j obtained, the degree of concordance between the data was scored according to the proposition of Landis, Koch (17). In this study, an intra-examiner concordance level that scored at least ‘Good’ was considered adequate according Landis, Koch (17). In this study, the j value was 0.89. The recorded points were defined according to the working posture of the student to analyse the extension and flexion of the wrist, arm, neck, trunk and legs, forearm pronation, supination and twist of the wrist. These points were defined in the pilot study. The pictures were analysed using the Image Tool program (18) in which the angles of body regions of interest were measured. ª 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd Eur J Dent Educ 18 (2014) 142–146
Musculoskeletal disorders in dental students
Posture assessment method The working postures of each student were evaluated using the Rapid Upper Limb Assessment – RULA, recommended by McAtamney and Corlett (19). This method was selected, because it is easy to learn how to use and apply it, and it is indicated for the ergonomic investigation of work stations of sedentary activities. According to RULA, a score is attributed to a region of the body with the lowest value being related to postures in which minimal risk factors are present. Only one side of the participant’s body was assessed at each time; usually, the side evaluated corresponded to the dominant hand of the student. Each individual’s body was divided into two groups, A and B. Regions of the body evaluated are group A: arm (extension from 20° to flexion of 20°, extension >20° or 20—45° of flexion, flexion of 45—90° and flexion of 90° or more); forearm (flexion of 60—100° and flexion of 90º or more); wrist (neutral position, flexion or extension of 0—15°, and flexion or extension >15°), wrist torsion (half distance of torsion and complete torsion); and group B: neck (flexion of 0—10°, flexion of 10—20°, flexion >20°, and if in extension), trunk (seated posture and well supported with the trunk/hips forming a 90° angle with the thighs, flexion of 0—20°, flexion of 20—60º, flexion >60º) and legs (seated, with legs and feet well supported, with body weight equally distributed; or standing up, with body weight equally distributed between the legs, with space to change position or legs and feet with adequate support or body weight poorly distributed). After obtaining the postural scores for each body part, the form of the muscular action is also evaluated (posture that is not static and with repetition lower than four times per minute; posture that is static for a time of
The association between restorative pre-clinical activities and musculoskeletal disorders P. A. Corrocher1, C. D. Presoto2, J. A. D. B. Campos1 and P. P. N. S. Garcia1 1 2
Department of Social Dentistry, Araraquara Dental School, UNESP, Univ Estadual Paulista, Araraquara, Brazil, Department of Restorative Dentistry, Araraquara Dental School, UNESP, Univ Estadual Paulista, Araraquara, Brazil
Keywords occupational hazards; human engineering; dental students; musculoskeletal disorders. Correspondence Patrıcia P. N. S. Garcia Department of Social Dentistry Araraquara Dental School UNESP Univ Estadual Paulista Rua Humait a 1680, Centro Araraquara CEP: 14.801-903, Brazil Tel: +55 16 3301 6405 Fax: +55 16 3301 6343 e-mail: [email protected]
Abstract Objective: To evaluate the risk of development of musculoskeletal disorders in the upper limbs of undergraduate dentistry students during the execution of pre-clinical laboratory activities based on gender, type of dental procedure and area of the mouth under treatment. Methods: Male and female undergraduate students in the second year of the Araraquara Dental School, UNESP, were enrolled in this study. Digital photographs were obtained whilst the subjects performed laboratory activities. The working postures adopted by each student were evaluated using the Rapid Upper Limb Assessment (RULA). The photos were analysed by a calibrated researcher (k = 0.89), and a final risk score was attributed to each analysed procedure (n = 354). Descriptive statistical analyses were performed, and the associations of interest were analysed by the chisquare test (P = 0.05).
Accepted: 5 October 2013 doi: 10.1111/eje.12070
Results: During most of the laboratory procedures performed, the risk of developing musculoskeletal disorders was high (64.7%; – IC95%: 59.7-69.7%), with no significant association between the RULA final score and gender (v2 = 1.100; P = 0.577), type of dental procedure (v2 = 5.447, P = 0.244) and mouth area treated (v2=4.150; P = 0.126). Conclusions: The risk of developing musculoskeletal disorders was high in undergraduate dentistry students; this risk was not related to gender, type of dental procedure and region of the mouth being treated.
Introduction Dentists are predisposed to various occupational diseases due to their work environment (1, 2). Whilst performing dental procedures, they may be required to remain in uncomfortable positions for long periods of time, such as twisting of the spine and neck, bearing increased shoulder load, repetitive movements and prolonged fixed postures, which may have detrimental effects on their health (3, 4). Musculoskeletal disorders include a group of diseases caused by excessive and repetitive daily laborious activities, which can affect the muscles, joints, nerves, blood vessels and tendons (5). When these disorders are related to work, they can be
142
characterised by the occurrence of various concomitant symptoms, for example pain, numbness, heaviness and fatigue mainly in the affected body part (6). Musculoskeletal disorders principally affect the upper limbs of a dentist and often result in temporary or permanent work disability (7, 8). A dentist’s work environment has improved in recent years, allowing the professional to work in a sitting posture, to rationalise their work and to adopt ergonomic postures (9, 10). However, despite these advances, dental professionals are at a high risk of developing diseases caused by their working posture (1, 2, 5, 11). To tackle the increasing prevalence of these disorders, prevention techniques must be adopted as early as possible,
ª 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd Eur J Dent Educ 18 (2014) 142–146
Corrocher et al.
preferably when a dentist is still under training at an institution, for example during pre-clinical or laboratory activity (11–14), because postural defects can be more easily identified and corrected during this initial learning phase (1, 15). Thus, the aim of the present study was to assess the risk of development of musculoskeletal disorders in the upper limbs of dentistry students during the execution of pre-clinical laboratory activities, with respect to the gender, procedures performed and mouth area treated.
Materials and methods Sample design This observational study included all second-year undergraduate students of the Araraquara Dental School (UNESP) who agreed to participate in this study. The study was approved by the Ethics Research Committee of the Araraquara Dental School, UNESP (Protocol number 53/10). The working postures adopted by these students whilst they performed pre-clinical activities in the Laboratory of Operative Dentistry were evaluated in this study.
Records of working postures For this study, we obtained digital photographs of the working postures adopted by the enrolled students during the various laboratory procedures linked to the restoration of dental elements (n = 354). The photographs were taken at least 10 min after the activities started, hence allowing the students to become comfortable in their postures. The sequential photographic records for different parts of the body were carried out with the photographer holding the camera close to the eyes at a distance of about 1.5 m from the ground, orthogonally. The photographs were taken by two researchers, previously trained in the pilot study, who were different from the professor in ergonomics. These photographs were evaluated by a researcher after intra-examiner calibration to assess the intra-examiner reliability of the postural assessments; a reproducibility study was conducted within the pilot study. In this study, the researcher examined the postures adopted by the undergraduate students in duplicate whilst performing 50 pre-clinical procedures, with an interval period of 1 week between assessments. The intraexaminer concordance of the risk score for the development of musculoskeletal disorders was estimated using linear-averaging kappa statistics (16) With regard to the value of j obtained, the degree of concordance between the data was scored according to the proposition of Landis, Koch (17). In this study, an intra-examiner concordance level that scored at least ‘Good’ was considered adequate according Landis, Koch (17). In this study, the j value was 0.89. The recorded points were defined according to the working posture of the student to analyse the extension and flexion of the wrist, arm, neck, trunk and legs, forearm pronation, supination and twist of the wrist. These points were defined in the pilot study. The pictures were analysed using the Image Tool program (18) in which the angles of body regions of interest were measured. ª 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd Eur J Dent Educ 18 (2014) 142–146
Musculoskeletal disorders in dental students
Posture assessment method The working postures of each student were evaluated using the Rapid Upper Limb Assessment – RULA, recommended by McAtamney and Corlett (19). This method was selected, because it is easy to learn how to use and apply it, and it is indicated for the ergonomic investigation of work stations of sedentary activities. According to RULA, a score is attributed to a region of the body with the lowest value being related to postures in which minimal risk factors are present. Only one side of the participant’s body was assessed at each time; usually, the side evaluated corresponded to the dominant hand of the student. Each individual’s body was divided into two groups, A and B. Regions of the body evaluated are group A: arm (extension from 20° to flexion of 20°, extension >20° or 20—45° of flexion, flexion of 45—90° and flexion of 90° or more); forearm (flexion of 60—100° and flexion of 90º or more); wrist (neutral position, flexion or extension of 0—15°, and flexion or extension >15°), wrist torsion (half distance of torsion and complete torsion); and group B: neck (flexion of 0—10°, flexion of 10—20°, flexion >20°, and if in extension), trunk (seated posture and well supported with the trunk/hips forming a 90° angle with the thighs, flexion of 0—20°, flexion of 20—60º, flexion >60º) and legs (seated, with legs and feet well supported, with body weight equally distributed; or standing up, with body weight equally distributed between the legs, with space to change position or legs and feet with adequate support or body weight poorly distributed). After obtaining the postural scores for each body part, the form of the muscular action is also evaluated (posture that is not static and with repetition lower than four times per minute; posture that is static for a time of
