Indian Journal of Dental Sciences

ORIGINAL ARTICLE
Year
: 2021  |  Volume : 13  |  Issue : 4  |  Page : 260--266

Evaluation of neck pain and scapular stability in graduate dental students: A cross-sectional study


Chhaya V Verma, Krutika S Bhosale 
 Physiotherapy School and Centre, T.N. Medical College, B.Y.L. Nair Ch. Hospital, Mumbai, Maharashtra, India

Correspondence Address:
Krutika S Bhosale
Physiotherapy School and Centre, T.N. Medical College, B.Y.L. Nair Ch. Hospital, Mumbai Central, Mumbai - 400 008, Maharashtra
India

Abstract

Background: There is a high prevalence of work-related musculoskeletal disorders in dentists. The most commonly affected areas are the neck, low back, wrist, and hand. The symptoms of the musculoskeletal disorder occur during the educational and training course in dental students. Aim: The aim of this study was to assess neck pain and the scapular stability in graduate dental students. Study Design: This was an observational, cross-sectional study. Study Setting: This study was conducted at a dental college attached to a tertiary care hospital. Methods: The site of pain over the neck region (in subjects with pain) was assessed using body diagrams. Assessment of intensity of pain (if present) was done using Numerical Rating Scale, scapular posture using the pectoralis minor (PM) length test and resting scapular upward rotation using Baseline Bubble Inclinometer, dynamic scapular positioning using Lateral Scapular Slide Test, and muscle strength of scapular stabilizers using Lafayette Manual Muscle Tester. The outcome measures were compared between 1st-year undergraduate dental students (Group A) and dental interns (Group B). Results: Sixty-three female dental students (Group A, n = 32; Group B, n = 31) were included. There was a significant difference in the PM length test of left side (P = 0.02) and intensity of pain (right side P = 0.008, left side P = 0.003) in Groups A and B. The site of pain was over the lateral aspect of the neck and the character of pain was aching. We found no significant difference in other outcome measures. Conclusion: Dental students suffer from neck pain. Static scapular posture was affected, whereas the dynamic scapular stability was not affected.



How to cite this article:
Verma CV, Bhosale KS. Evaluation of neck pain and scapular stability in graduate dental students: A cross-sectional study.Indian J Dent Sci 2021;13:260-266


How to cite this URL:
Verma CV, Bhosale KS. Evaluation of neck pain and scapular stability in graduate dental students: A cross-sectional study. Indian J Dent Sci [serial online] 2021 [cited 2021 Dec 8 ];13:260-266
Available from: http://www.ijds.in/text.asp?2021/13/4/260/327810


Full Text



 Introduction



Dental procedures are performed within a small workplace, i.e., the oral cavity using small dental instruments that require exceptional skill, precision, and prehensile activities of the hand. The dental work is done majorly in sitting and occasionally in standing. Position frequently attained by the dentist is of neck bending, rotation, shoulder elevation, elbow bending, and wrist extension for eye–hand co-ordination. Posture is defined as the attitude assumed by the body either with support during muscular inactivity or by means of the coordinated action of many muscles working to maintain stability or to form an essential basis which is being adapted constantly to the movement which is superimposed upon it.[1] An optimal posture, muscle flexibility, and muscle strength are required for adequate physical functioning. Stability of proximal joints, i e., forearm, shoulder, neck, and trunk is required for performing precision activities adequately.

Scapular stability depends on the flexibility and strength of scapular muscles as well as dynamic scapular positioning with shoulder movements. The scapular muscles play a crucial role in the stabilization of the neck and shoulder to maintain neutral alignment and produce coordinated movements of the shoulder girdle. The sustained posture of the forward head and rounded shoulders during the dental work lead to tightness of the anterior muscles, i.e., the pectoralis minor (PM) and major, scalene, sternocleidomastoid, etc. The posterior muscles serratus anterior, middle trapezius, lower trapezius, and rhomboids help the scapula maintain its normal position overcoming the shear force of the anterior muscles. These muscles fatigue and become weak due to the forward head posture and protraction of shoulders assumed by the dentists during their clinical work. Frequent elevation of shoulders causes over-activity, spasm, and tightness of the upper trapezius and levator scapulae. This muscle imbalance, called upper crossed syndrome,[2] leads to abnormal movement pattern called scapular dyskinesia,[3] where the glenohumeral joint and scapulothoracic joints do not function synchronously. Abnormal movement patterns increase the stress on joints giving rise to musculoskeletal pain. With adequate rest intervals and exercise including stretching and strengthening, these abnormalities can be reversed. However, due to poor work culture in dental setups, there are insufficient rest pauses during the work, so the rate of damage exceeds the rate of repair leading to early degenerative conditions.

These prolonged static, awkward postures, forceful repetitive movements of the hand, inappropriate work patterns, and inadequate rest intervals are the risk factors for the development of work-related musculoskeletal disorders (WMSDs).[4] Musculoskeletal disorders (MSD) are injuries or disorders of the muscles, nerves, tendons, joints, cartilage, and spinal discs. There is a high prevalence of WMSDs in dentists, which are associated with work posture, work experience, lifestyle, environmental factors, etc. The most commonly affected areas are the neck, low back, wrist, and hand.[5],[6] It has been found that symptoms of the musculoskeletal disorder occur during the educational and training course in the dental students[6] which can lead to injury, decreased work capacity and efficiency, and hamper their career.

As the scapula is a connecting link to transfer forces from the upper extremity to the spine, scapular stability is essential for maintaining posture and performing movements of the upper extremity and neck required in dental practice. Thus, our study aimed to assess and compare neck pain and scapular stability in graduate dental students (between 1st-year graduate dental students and dental interns).

 Methods



The Bachelor of Dental Surgery in Maharashtra University of Health Sciences is a 5-year course including 1 year of internship. The 1st year of this curriculum includes lectures and practicals. Their clinical dental practice starts in the 3rd year. In the 3rd and 4th year, students are posted in clinics and taught about the assessment and treatment of patients. Interns perform their individual supervised full-fledged clinical practice. Interns work continuously for 6 h and treat 15–20 patients with ½ h break throughout the day. The treatment time of each patient ranges from 15 to 45 min depending on the procedure.[7]

This cross-sectional study was planned as per the Helsinki Declaration of 1975 (revised in 2020) and commenced after the permission of the Institutional Ethics Committee and the Dean of the Dental College attached to a Municipal tertiary care hospital in Mumbai. The 1st-year graduate dental students and dental interns willing to participate were included in the study. The exclusion criteria were subjects with any musculoskeletal or neurological condition, traumatic injury, involved in any regular sports (e.g., racquet sports), and fitness activity. The batch of interns in this dental college consisted of 42 students. Eight were male students, out of which four were involved in sports activities, hence, were excluded from the study. We decided to exclude the remaining four males in order to avoid the skewness in the data and include only females. First-year graduate dental students were taken as a comparison group as they were novice to the profession, not exposed to the risk factors leading to WMSD. Thus, the estimated sample size was 30 in each group (Group A: First-year graduate dental students, Group B: dental interns) using the convenient sampling method. The subjects in Group A were randomly selected using the chit method. Written informed consent was taken from the subjects before data collection.

In this study, scapular resting posture assessment was done using the PM length test and measurement of the resting scapular upward rotation (UR) angle, scapular asymmetry using Lateral Scapular Slide Test (LSST), and muscle strength of scapular muscles.

Pain assessment

The subjects were asked if they experienced pain in the neck region. The site of pain was marked on the body diagram. The character of pain was also documented in subjects who complained of pain. The neck region was considered as the area extending from the superior nuchal line to the spine of the scapula posteriorly and the superior border of the clavicle laterally.[8] Pain intensity was assessed using the Numerical Rating Scale for pain (NRS).[9]

Pectoralis minor length test

The PM length test was performed in a supine position with arms by the side in a neutral position, elbow flexed, and rested on the trunk. The linear distance from the treatment table to the posterior border of the acromion was measured in centimeters (cm) using a rigid standard plastic transparent right angle (set square) [Figure 1]. The normal value for PM length by this method is 2.54 cm according to Sahrmann. An increase in this distance suggests PM tightness causing increased anterior tilt and internal rotation of the scapula.[10]{Figure 1}

Scapular upward rotation test

The scapular UR test was performed in a standing position with arms by the side in a neutral position. A baseline bubble inclinometer was placed midway on the spine of the scapula and the angle shown by the bubble was documented in degrees [Figure 2].[11]{Figure 2}

Lateral scapular slide test

Dynamic scapular positioning was assessed using LSST in three positions as described by Kibler.[12]

Test position 1 - Arms relaxed by the side [Figure 3]aTest position 2 - Both hands were placed on ipsilateral hips [Figure 3]bTest position 3 - Both elbows were extended, shoulder elevated, and maximally internally rotated, thumbs down, both arms at 90° in the coronal plane [Figure 3]c.{Figure 3}

The distance between the inferior angle of the scapula and the closest thoracic spinous process in the same horizontal plane was measured bilaterally with a measuring tape in these three positions in centimeters. If the difference between the measures of both sides in these three positions is >1.5 cm, Kibler noted it as scapular dysfunction.

Muscle strength of scapular stabilizers

Muscle strength of upper, middle, lower trapezius, serratus anterior, and rhomboids was assessed using the Lafayette Manual Muscle Tester as described by Michener et al.[13] Muscle testing was performed according to the positions described by Kendall with the scapula in a mid-range position of scapular motion for specific muscle. A “break” test was performed, i.e., maximum isometric contraction. The subject was instructed to maintain a mid-range position during each muscle test and resistance was applied through Lafayette Manual Muscle Tester until the examiner matched the subject's effort. The amount of force applied was measured in kilograms [Figure 4]a,[Figure 4]b,[Figure 4]c,[Figure 4]d,[Figure 4]e.[13]{Figure 4}

Statistical analysis

The data were analyzed using GraphPad Software, Inc. California Corporation, San Diego, California (August 2019). Data were assessed for normality using the Shapiro–Wilk test as it is sensitive for smaller sample sizes (n < 50). Unpaired t-test and Mann Whitney U-test were used for comparison of outcome measures between Groups A and B. The confidence interval was set as 95% and the significance level was set as 0.05.

 Results



Out of the 34 females in the batch of interns, three were not willing to participate in the study. Hence, 31 female interns (Group B) participated in the study. The batch of 1st-year students consisted of twenty males and forty females. An equivalent sample size had to be included in the comparison group, so 32 female 1st-year graduate (Group A) students willing to participate were selected randomly using the chit method. Demographic data are described in [Table 1]. All the participants in the study were right-side dominant. The clinical work was performed by dental interns majorly in sitting position and occasionally in standing position. Comparison of the outcome measures between Groups A and B is shown in [Table 2] and [Table 3]. The frequency of the presence of pain in Groups A and B is shown in [Figure 5]a and [Figure 5]b. The character of pain reported by all the subjects was aching (of muscular origin) and site of pain was over the lateral aspect (nape) of the neck. Eight students (25%) in Group A complained of pain bilaterally. In Group B, three students (9.6%) complained of unilateral pain, while 17 students complained of pain bilaterally.{Figure 5}{Table 1}{Table 2}{Table 3}

 Discussion



The objective of our study was to assess pain and scapular stability in 1st-year graduate dental students and dental interns who had completed their undergraduate course. To the best of our knowledge, this is the first study to focus on scapular stability in graduate dental students. The primary findings of the study are an increase in the anterior tilt of the scapula of the left side in interns using the PM length test [Table 2] and presence of neck pain in both the groups. A greater percentage of interns (65%) had complained of neck pain as compared to 1st-year students (25%) [Figure 5]a and [Figure 5]b. The intensity of pain was also higher in interns [Table 2]. Only females were included in the study as there were few males in the batch of interns to bring homogeneity in the data.

Neck pain in Group B could be attributed to numerous risk factors, including prolonged static postures; repetitive movements; suboptimal lighting; poor positioning and ergonomics; mental stress; physical conditioning; etc.[6],[14] Abooj et al. reported neck and shoulder pain in interns and dental practitioners associated with working hours, poor ergonomics, and work characteristics.[15] Some of the students in Group A also reported pain. This could be due to long hours of studying, reading books, use of laptop or computers,[16] backpack, use of smartphones and video games, which is very common in students.[17],[18] These activities in turn affect the posture of the dental students and give rise to musculoskeletal disorders. If done for prolonged duration, it causes fatigue of scapular stabilizer muscles leading to abnormal postures such as rounded shoulder and forward head as seen in the upper crossed syndrome. The posture of study, continuous hours of study, mode of study have been shown to be associated with neck pain.[19] Vidulasri and Thenmozhi assessed the prevalence of neck pain in different clinical areas and found that the rate of pain in dental students and practitioners involved in endodontics was higher than others.[20] The character of pain reported by the students in our study was aching suggestive of muscular origin. The pain site reported was over the lateral aspect of the neck suggestive of the involvement of the upper trapezius muscle. The upper trapezius muscle is overused during the seated dental procedures giving rise to sustained contraction and spasm.[21]

The PM tightness increases anterior tipping and downward rotation resisting UR of the scapula during shoulder elevation. Downward rotation and anterior tipping of the scapula decrease the space in the glenohumeral joint making it susceptible to tendonitis/impingement of the rotator cuff tendons during overhead activities.[22] The PM tightness could be caused due to the assumption of protracted shoulder position for the dental procedures. Dentistry is a bimanual procedure and hence both the upper limbs are performing some kind of static or dynamic work. The left side is usually used for stabilization of the jaw by the dentists for a long time which may lead to shortening of the PM muscle. Srijessadarak found a higher prevalence of upper cross syndrome in dental students at Khon Kaen University.[23] Ettinger et al. examined the influence of work in scapular tilt and rotation in dental hygienist which resulted in increased scapular anterior tilt after a workday which could be a predisposing factor for upper back or shoulder pain.[24] Vakili et al. had studied the prevalence of common postural disorders which included forward head, rounded shoulders, scoliosis, etc., in the dental staff of Tehran using an observational method with a plumb line. About 42.7% had reported work-related neck pain and 25% shoulder pain and 68.8% had rounded shoulders.[25] These findings are consistent with our results of the PM length test.

In our study, we found that the LSST was positive in a few students of both Groups A and B. However, there was no significant difference in this test between Groups A and B in our study. Joshi et al. had studied the association of scapular position with neck pain in dentists using LSST. This case–control study included 15 dentists in each group (with pain and without pain), who were working for more than 8 h, including both males and females with a mean age of 24 years. The study showed a significant difference in LSST in these groups. The working hours of the participants in this case–control study was more as compared to that of our study. Furthermore, the participants were more experienced which might have led to pain and adaptive changes in the posture.[26] However, our study does not support this finding as our subjects were budding dental students which are novice to the profession.

Studies have found the weakness in the scapular muscles of the painful side which are upper, middle, lower trapezius, and serratus anterior in the patients with mechanical neck pain.[27],[28] As the subjects in our study were young with Groups A and B consisting of a mixed population of subjects with and without pain, a significant difference in muscle strength could not be found [Table 3]. Hence, administrative controls such as scheduling, rotatory posting, and rest intervals should be implemented to relieve the physical stress. Engineering controls such as adequate illumination, ergonomic dental chairs, and use of magnifying loops[29] help in maintaining optimal posture.[30] The dental students should be educated about the prevalent WMSDs and implementation of correct ergonomics while working in the clinical area.[31] There is a need to inculcate the education about ergonomics in their syllabus since the 1st year itself. If the dental students are made aware about the effect of clinical work on their musculoskeletal health and its consequences at the beginning of their career, precautions such as energy conservation and joint protection techniques, implementation of ergonomics can be taken to prevent the WMSDs.

We recommend a longitudinal cohort design for this type of study wherein the same subjects can be assessed for 5 years from their 1st year to internship to study the effect of the dental profession on the scapular stability. However, due to time constraint, we had designed it as a cross-sectional observational study including two groups. The sample was collected from a single government institution and included only females; hence, the results cannot be generalized. We were unable to include postgraduate students due to their hectic schedules. Scapular stability can be compared among dental students and practitioners involved in various clinical areas such as prosthodontics, endodontics, orthodontics, oral surgery, and periodontics as work patterns and working postures are different among these areas.

 Conclusion



We conclude that most of the graduate dental students suffer from neck pain. Furthermore, we found that the static scapular stability but not dynamic scapular stability was affected in the graduate dental students.

Ethical clearance

Ethical clearance was sought from the Institutional Ethics Committee of T.N. Medical College, ECARP (Ethics Committee for Academic Research Projects). ECARP project no- ECARP/2017/216. This protocol was approved by ECARP on 8th March,2018.

Acknowledgment

We would like to acknowledge the Dean of T.N. Medical College and B.Y.L. Nair Ch. Hospital and the Dean of Nair Hospital Dental College, Mumbai, for permitting us to conduct the study. We are grateful to all the graduate dental students who voluntarily participated in the study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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