RESUMO
Objectives: This study aimed to observe the effect of different finger rest positions on the muscular activity of the hand, forearm, arm, shoulder, thorax, and neck, as well as on the angular deviation from the neutral position of the neck, trunk, upper arm, and forearm on the working side during pre-clinical procedures. Methods: An experimental laboratory study was performed. Response variables were muscle activation of the abductor pollicis, brachioradialis, biceps brachii, deltoid, pectoralis major, and right sternocleidomastoid muscles and angular deviation from the neutral position of the neck, trunk, arm, and forearm during simulated clinical procedures. Independent variable was finger-rest position during cavity preparation (no finger rest, usual rest, and ergonomic rest). Class I cavity preparations (N = 120) were performed on artificial first molars (16, 26, 36, and 46) (N = 120). Muscular activation was assessed by surface electromyography and angular deviations using Software for Postural Assessment (SAPO) version 0.69. One-way analysis of variance and Tukey's or Games-Howell's post-hoc tests were performed (α = 0.05). Results: For the sternocleidomastoid muscle, there was no statistically significant difference between the different rest positions. For the deltoid muscle, work with no finger rest resulted in greater muscle activation (p < 0.001) during work on tooth 36. Regarding the pectoralis major and right brachioradialis muscles, we observed that for both teeth 16 and 26, working with ergonomic rest showed less muscle activation. Muscle activation of the right biceps brachii was higher for work with no rest in both the upper and lower arches, differing significantly only from the usual rest in tooth 16 (p < 0.001), usual rest and ergonomic rest in teeth 26 and 46 (p < 0.001), and only ergonomic rest in tooth 36 (p = 0.044). In the right abductor pollicis muscle, work with ergonomic rest resulted in less muscle activation for cavity preparation in teeth 16, 26, and 36, which was significantly different from work with no rest (p = 0.029, p < 0.001, and p = 0.013, respectively). Regarding angular deviation, it was observed that for tooth 16, there was a greater angular deviation of the arm when performing cavity preparations with no finger rest. For teeth 26 and 46, the ergonomic finger rest provided lower angular deviation from the neutral position of the right arm. For tooth 36, ergonomic rest provided less angular deviation from the neutral neck position. Conclusion: In general, the use of non-active finger rest during simulated cavity preparations, regardless of the type of rest, provided less muscle activation and angular deviation from the neutral position of the body's upper extremity when performing pre-clinical procedures.
RESUMO
OBJECTIVE: The aim of this study was to evaluate the dental students' fine motor skills and their compliance with ergonomic posture techniques over the course of a preclinical training year. The correlation between fine motor skills and compliance was also assessed. METHODS: The ergonomic posture of students enrolled in the second year of a five-year undergraduate dental degree programme (n = 62) was assessed using the Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP). This assessment relied on photographs of the students performing preclinical laboratory procedures during the school year. The photographs of each procedure received a score, and the final score obtained (0 to 10) corresponded to the extent of the student's compliance with ergonomic posture techniques. Initial compliance was calculated during the first two months of the training programme, whilst final compliance was calculated during the last two months. Fine motor skills were evaluated using the modified Dental Manual Dexterity Assessment (DMDA), which was also applied at the beginning and the end of the school year. Data were assessed statistically by Student's paired t test, and the correlation between fine motor skills and compliance with ergonomic posture techniques was estimated by Pearson's correlation coefficient (r) and Student's t test (α = 0.05). RESULTS: The compliance scores were higher at the end of the academic year than at the beginning of year (p < 0.001; t = -5.300). Fine motor skills improved significantly with time (p < 0.001; t = -10.975). Non-significant correlations were found between students' fine motor skills and their economic posture compliance both at the beginning (r = -0.197; p = 0.126) and at the end of the training year (r = 0.226; p = 0.078). CONCLUSION: The students' manual dexterity and compliance with ergonomic posture techniques increased over the course of the preclinical training year, and the correlation between students' fine motor skills and their ergonomic posture compliance was not significant.