2021, Number 4
Working posture and its relationship with the development of future musculoskeletal disorders in dental students at the Catholic University of Cuenca, Ecuador
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ABSTRACT
Introduction: the practice of inadequate postures and repetitive movements are frequent in the dental practice, carried out to achieve better visibility of the operative field, leading the professional to physical fatigue, maintaining this type of work posture for a prolonged period can develop musculoskeletal alterations. Objective: to analyze the working position and the type of muscle-tendon pain in fifth-year dental students of the Catholic University of Cuenca, Ecuador. Material and methods: cross-sectional, descriptive study was carried out using visual analysis and an evaluation of musculoskeletal disorders in 125 fifth-year students of the dental career at the Catholic University of Cuenca, Ecuador, obtaining the sample in a population of 185 students. To evaluate the type of muscle-tendon pain present in the students we used the Kuorinka Nordic questionnaire and to determine the working position of the students in the dental unit we used the BHOP postural checklist. Results: the Nordic questionnaire showed that 67.2% (n = 84) of the participants evaluated presented pain, compared to 32.8% (n = 41) of the participants who did not present pain. It was notorious the presence of pain at the back level with 37.2% (n = 71), followed by neck pain with 30.4% (n = 58); right hand and wrist with 12.6% (n = 24); right shoulder with 6.8% (n = 13); left shoulder and right elbow-forearm corresponding to 4.7% (n = 9) each, with left elbow-forearm with 2.1% (n = 4) and left hand-wrist with 1.6% (n = 3). The results of the BHOP postural checklist indicated that 1.6% (n = 2) have maximum balance position, but 98.4% (n = 123) possess inadequate working posture. Conclusions: the working postures verified during the clinical procedures were mostly incorrect, and inadequate posture maintained for a prolonged time can develop long-term musculoskeletal alterations, in an initial phase pain, limited body mobility, and recurrent muscle spasms are present.INTRODUCTION
Nowadays, the practice of inadequate postures and repetitive movements are frequent, performed to get a better visibility of the operative field, leading the professional to physical and mental fatigue, an incorrect working posture and kept for a long time, together with the years of practice will cause pathologies in the musculoskeletal system, It is important to know the position of maximum equilibrium defined as the disposition of the body, trunk, lower extremities, neck and head that must assure balance and stability,1 internationally known as BHOP (Balanced Human Operating Position) its objective is to avoid muscular tension of the skeleton, working with the greatest amount of muscles in semi-relaxation,2 it is characterized by maintaining a straight back, in which the spine is perpendicular to the patient, thighs parallel to the floor and separated by an angle of 60o, the legs will be perpendicular to the floor forming an angle of 90o at the knee, the arms should be perpendicular to the floor, together, the forearm should form an angle of 90o without contacting the body (Figure 1).3
This will facilitate a balanced load of forces, and a minimum cervical flexion, which allows observing the oral cavity indirectly, the distance between the patient's head and the operator should be approximately 30 to 35 cm.4 In professional practice, it was found that five out of six dentists experienced muscular discomfort and pain at some time in a period of 6 to 12 months, with the neck and shoulders being the areas of greatest discomfort.5,6 Among the repetitive postural strain injuries that affect dental personnel, we have mainly: Carpal tunnel syndrome, which is the result of microtrauma due to manual labor, torsions, extensions, flexions, and vibrations. Its symptoms are of a long evolution, usually occur at night, with pain, paresthesia, hypoesthesia, and rarely radiates to the forearm and elbow,7 it is characterized by inflammation and pressure inside the tunnel, formed by the carpal bones and the transverse carpal ligament, there may be numbness in the thumb, index finger, people who suffer from carpal tunnel syndrome report clumsiness when grasping objects, problems with coordination movements, in the diagnosis it is important to observe the Phalen's sign which consists in the complete flexion of the wrist during one minute, this will produce pain.8 The treatment usually begins with the application of a splint to be used at night, anti-inflammatory drugs that will relieve pain and numbness, and an injection of corticosteroids may also be recommended which will contribute to the reduction of inflammation, it is important to keep the hand in a neutral position that is to say the wrist joint should be straight and not downward if the symptoms are severe the treating physician will recommend surgery to release the carpal tunnel and eliminate the pressure exerted by the median nerve.9
Quervain's syndrome presents as inflammation and irritation of the tendons that extend from the dorsal side of the thumb down the wrist, consequently, the tendon becomes inflamed, the movements of the thumb and wrist are painful,10 it is characterized by pain in the dorsal side of the thumb, numbness in the thumb and index finger, swelling in the wrist, stiffness when moving the thumb or wrist. For the diagnosis, the Finkelstein maneuver is used, which consists of the person closing the fist by squeezing the thumb with the other fingers, then turning the wrist in the direction of the little finger, this maneuver will produce a lot of pain, and the treatment is controlled with anti-inflammatory drugs and rest of the affected hand using a thumb immobilizer, the objective is to obtain good results between 7 and 10 days.11
In the types of prevention of musculoskeletal disorders we have primary prevention being the set of measures that are carried out before the development of a disease, such as evaluation of the workplace, taking into account the height, position, support surfaces, distances and visual angles, ventilation, temperature of the workplace and of the components of the dental office, short rests of 3 minutes are recommended between each patient, as for secondary prevention it is based on Stretching or stretching techniques, which is characterized by reducing and preventing pain caused by musculoskeletal alterations, allows the development of flexibility to correct poor posture and even improve some postural pathologies at the spine level such as scoliosis, kyphosis and lordosis, also cervicalgia, dorsalgia, low back pain, sciatic nerve problems and helps to relieve pain caused by lack of physical exercise and the accumulation of the tensions of daily life, it is recommended to practice it at least two or three times a week, since it takes about 15 minutes, which will provide a favorable physical condition and welfare.12
MATERIAL AND METHODS
This is a cross-sectional and descriptive research carried out through a visual analysis and an evaluation of musculoskeletal disorders in 125 students who have provided dental care for a period of approximately three years, aged between 22 and 25 years in the fifth year of the Dental School of the Catholic University of Cuenca, Ecuador, this sample was obtained based on a population of 185 students using inclusion and exclusion criteria with the objective of determining the type of muscle-tendon pain present in the students using the Kuorinka Nordic questionnaire, standardized questionnaire for the detection and analysis of musculoskeletal symptoms applicable in the context of ergonomic or occupational health studies detecting the existence of initial symptoms, which have not yet constituted a disease or have not led to consult a doctor, is useful for collecting information on pain, fatigue in different body areas, the questionnaire was answered by indicating which part of your body presents pain, discomfort, however, for the study modifications have been made.13
To determine the working position of the students in the dental unit, the BHOP. Postural checklist was used, and visual analysis was used to determine the correct position when working with the patient,14 this analysis was carried out by the researchers, with previous standardization for the correct application of the technique.
RESULTS
Of 125 participants it was found that 67.2% (n = 84), presented pain, compared to 32.8% (n = 41) of participants who did not present any type of pain, it is important to note that the right hemisphere corresponds to the skilled part of the student and the left hemisphere corresponds to the unskilled part, it was also found that the presence of pain at the back level is greater with 37. 2% (n = 71) followed by the pain present in the neck with 30.4% (n = 58); right hand and wrist with 12.6% (n = 24); right shoulder with 6.8% (n = 13); left shoulder and right elbow-forearm corresponding to 4.7% (n = 9) each, left elbow-forearm with 2.1% (n = 4) and finally left hand-wrist with 1.6% (n = 3).
It was found that the type of pain according to its location was greater at the neck level, 15 students had acute pain, 43 had chronic pain and 67 people had no pain in this area; in the right shoulder 15 people had acute pain, nine people had chronic pain, and 112 people had no discomfort in this area; likewise, in the left shoulder, four persons presented acute pain, five persons chronic pain and 116 persons without discomfort; when evaluating the back area, it was found that 18 persons presented acute pain, 53 persons chronic pain and 54 persons without any type of discomfort in this area, being the area with the most discomfort. In the right elbow-forearm, no person presented acute pain, but nine people presented chronic pain, and 116 people had no pain at this level. Likewise, in the left elbow-forearm, two persons presented acute pain, two persons presented chronic pain and 121 persons had no discomfort in this area. In the right hand-wrist, we found the presence of acute pain in seven people and chronic pain in 17 people, in 101 people no discomfort was found, and finally, we found that in the left hand-wrist we found one person with acute pain, two people with chronic pain and 122 people with no discomfort in this area (Table 1).
It could be observed that most of the discomfort was registered in the right area compared to the left, because the right area was the skillful part in most of the students who participated in the study, being 122 students right-handed and three left-handed, regardless of gender.
The following results were obtained in the postural checklist; out of 125 students it could be observed that only 1.6% (n = 2) have a position of maximum balance, 98.4% (n = 123) do not have an adequate working posture for one reason or another (Figure 2).
DISCUSSION
It was established that the prevalence of tendon muscle pain was 67.2% (84 people), compared to 32.8% (41 people) who did not present any type of pain, showing us that an inadequate position for a long period generated pain in the students, likewise, the pain was found in the back in 37.2%, neck 30. The pain was also found in the back in 37.2%, the neck in 30.4% due to the inclination and curvature that these structures adopt during clinical practice, in the right hand-wrist in 12.6%, in the right shoulder in 6.8%, left shoulder in 4.7%, right elbow, and forearm in 4.7%, left elbow, and forearm in 2.1% and finally in the left hand-wrist in 1.6%. Leggat15 2006 carried out a study on skeletal muscle disorders, applying the Nordic questionnaire to 285 dentists of the Dental Association of Australia, who were randomly selected. The study reported that 87.2% experienced musculoskeletal disorders, and found a higher prevalence of neck pain with 57.5%, back with 53.7%, and shoulder at 53.3%. Chavez16 2011, investigated the association that exists between the postures adopted in clinical work with the presence of musculoskeletal discomfort, 56 dentists from two health centers in the municipalities of Jalisco (Mexico) were surveyed. The participants reported neck pain at 40%, shoulders at 30% elbow at 20% hand and wrist at 40% upper back at 60%, and lower back at 50%. It can be observed that the results are similar to the present study, which reports pain in the neck with 30.4%; in shoulders, this percentage decreases to 8.9% and in hands, it totals 14.2%.
Linero17 2012, investigated to determine the prevalence of musculoskeletal symptoms in health personnel in the city of Bogota using the Nordic questionnaire. The population studied was 63 men and 139 women of whom, 29 (14.3%) were dentists and 10 (4.95%) dental assistants. The 64.8% reported osteomuscular symptoms, the most frequent was in the hands and wrists with 29.7%, neck with 28.2%, and back with 25.7%, when compared with the present study, similar results were found, but not close, the pain in the wrists was 14.2%; in the neck 30.4%; and in the back 37.2%. In the present research work, the prevalence of an inadequate posture was also evidenced; the same was reflected in the results of BHOP, in which 98.4% of the students do not have an adequate working posture, while only 1.6% of the students evaluated have an adequate posture. Briones18 2014, studied the correlation between the level of knowledge about ergonomic dental postures, working posture, and postural pain, in his research 50 dental students from the University of Guayaquil, Ecuador participated, and the study showed that 22.5% obtained a correct posture and 77.5% with an incorrect posture. In comparison with the present study, which had a sample of 125 participants in the fifth year of dentistry, 1.6% had a position of maximum balance and 98.4% had an incorrect posture. Bendezú19 2005 investigated the correlation between the level of knowledge of ergonomic postures, working postures, and postural pain in 22 dental students of the Cayetano Heredia University of Peru; he found that 22.3% had a correct posture while 77.7% had an incorrect working posture. Few are studies that incorporate several evaluation methods, most are limited to only one, in the present investigation it has been possible to incorporate these two evaluation methods, in which it was possible to register that pain and the level of risk are directly associated with an inadequate posture, this added to working days of approximately eight hours, will make the dental assistants more susceptible to the development of diseases and irreversible consequences.
CONCLUSIONS
The working postures verified during the clinical procedures were mostly incorrect, an inadequate posture maintained for a prolonged period can develop long-term musculoskeletal alterations, in an initial phase there is pain, limited body mobility, and recurrent muscle spasms.
ACKNOWLEDGEMENTS
To the Faculty of Dentistry of the Catholic University of Cuenca, Ecuador, for having allowed the realization of this research work, collaborating on time with the technical assistance of the study.
REFERENCES
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Briones Villafuerte AV. Posturas odontológicas ergonómicas y dolor muscular, durante las prácticas clínicas del Estudiante del 5to año de la facultad de Odontología periodo 2013 [Tesis]. Guayaquil: Universidad de Guayaquil; 2014. Disponible: http://repositorio.ug.edu.ec/bitstream/redug/5675/1/BRIONESandrea.pdf
Bendezú Aguirre NA, Valencia Tapia E, Aguilar mendoza LA, Vélez Fonseca C. Correlación entre el nivel de conocimientos sobre posturas odontológicas ergonómicas, posturas de trabajo y dolor postural según zonas de respuesta, durante las prácticas clínicas de estudiantes en una Facultad de Estomatología. Rev Estomatol Herediana. 2006; 16 (1): 26-32.
AFFILIATIONS
1 Odontóloga, Maestría en Dirección y Gestión Sanitaria. Departamento de Investigación de la Unidad Académica de Ciencia Odontológica de la Universidad Católica de Cuenca, Ecuador.
2 Odontólogo, Bioestadístico, Magíster en Estomatología, PhD en Ciencias de la Salud. Departamento de Investigación de la Unidad Académica de Ciencia Odontológica de la Universidad Católica de Cuenca, Ecuador.
3 Doctor en Medicina y Cirugía, Magíster en Salud Ocupacional. Departamento de Investigación de la Unidad Académica de Ciencia Odontológica de la Universidad Católica de Cuenca, Ecuador.
Financiamiento: el presente proyecto investigativo se financió por los autores para su ejecución y conclusión.
Research support: this research project was financed by the authors for its execution and conclusion.
CORRESPONDENCE
Katherine Elizabeth Correa-Carrera. E-mail: kthy7c@gmail.comReceived: Agosto 2017. Accepted: Enero 2018.