INTRODUCTION:

The practice of dentistry is demanding and stressful. The field of oral surgery in particular forms the core of dentistry. Extraction is one of the commonest procedures performed at the under graduate level. Physical factors that incur musculoskeletal problems among dentists can be largely divided into three areas namely, work environment, hand strength, and posture. The work environment includes unit chairs and devices. Hand strength is determined by the material or surface texture of devices and gloves and the posture used to maintain and control devices requiring strong force during dental procedures causes musculoskeletal disorders.

Operator position in oral surgery is an important aspect in the success of dental treatment. Chair positions of both the operator and patient have a pivotal role in the determining the success of an extraction. Proper chair positions also help to avoid musculoskeletal problems in the operator. Dentists are more vulnerable to occupational health hazards, because their long working hours and maintenance of same postures without micro-breaks result in MSDs causing pathologies such as tendinitis, synovitis, tenosynovitis, and bursitis[1].

Lower back, neck and shoulders are the most commonly affected body sites. According to previous studies the prevalence of musculoskeletal disorders was found to be generally higher in women than men, which is attributed to lower muscle volume, physical strength of women and female hormones. However, except for the wrist, there were no significant gender differences in musculoskeletal disorders[2].

Dentists who work more often in the sitting position have showed a higher incidence of severe low back pain than dentists who often alternate between sitting and standing postures[3]. Another fact is that dentists those who sat at least 80% of the time worked less hours and had less of a workload during their working hours. High frequency of pain and high risk levels, according to the RULA method, suggest inappropriate and incorrect ergonomic postural habits existing among dental professionals[2].The posture required to treat the maxillary second molar was reported to cause considerably greater pain than that required to treat anterior teeth[4].

Proper positioning permits a clear view of the teeth being worked on and allows easy access to the teeth during instrumentation. This study observes chair positions in tooth extractions performed by undergraduate students and examines whether the correct position is being followed.

MATERIALS AND METHODS:

This study was an observational study. On the whole 24 extraction procedures were observed. All the students were final year students and interns of a city-based private dental college. The observation was about the patient and operator chair position during extraction. 12 procedures were performed by final year students and another 12 by interns.

Neither the operator nor the patient was informed beforehand about the observation. It was kept secretive. First all the information about the patient and clinician as mentioned above were recorded. Then the tooth number was noted down. As the extraction proceeded, the chair position of the operator and patient were observed and taken down. Changes in the chair positions during the course of extraction were also observed. The clinician was particularly observed for his skill in extracting the entire tooth. If the extraction was in pieces, a note was made.

The patient details included name, age, sex, occupation and OP number while the clinician details included name and year of study.

Under operator position the clock position, sitting or standing position, grip of instruments and the position supporting hand were considered.

The observations made under the patient position were the chair position, chair height, chin, thigh and head positions.

STATISTICAL ANALYSIS:

Final year students

Table. 1. Number of procedures in which the positions were followed correctly

Position	Number of. Procedures	Percentage of procedures
Clock position	9	75%
Patient Chair position	9	75%
Patient chair height	4	33.33%
Chin position	11	91.67%
Head position	7	58.33%

Figure. 1

Table. 2. The most preferred clock position among operators of final year

Clock position	Number of procedures	Percentage of procedures
8 O' clock	6	50%
9 O' clock	2	16.67%
10-11 O'clock	1	8.33%
12 O'clock	3	25%

Figure. 2

Interns

Table. 3. Number of procedures in which the positions were followed correctly

Positions	Number of procedures	Percentage of procedures
Clock position	10	83.30%
Patient chair position	12	100%
Patient chair height	6	50%
Chin position	12	100%
Head position	7	58.33%

Figure. 3

Table. 4. The most preferred clock position among interns

Clock position	Number of procedures	Percentage of procedures
8 O'clock	9	75%
9 O'clock	2	16.67%
10-11 O'clock	0	0%
12 O'clock	1	8.33%

Figure. 4

RESULTS:

The extent to which the patient and operator chair positions are being followed progressively increases from final year students towards interns. This can be attributed to increased experience and attainment of knowledge about chair positions.

DISCUSSION:

This study aimed at observing the various chair positions followed by both the operator and patient during extractions. The results of this study revealed the extent to which the chair positions to be followed are being implemented in clinical practice.

Among final years, the practice of following proper chin position is properly implemented (91.67%)which is to be lauded. But attention must be paid to patient chair height which has been followed only in 33.33% of the procedures. This causes discomfort to the patient as well as paves way for musculoskeletal problems in these students. This also leads to drooping posture of the operator and bending while working which can inflict pain in the shoulders and back region. Coming to the clock position, 8 o'clock position is found to be the commonest position among final year students (50%).

Among interns, the patient chair positions (100%) and chin positions (100%) are perfectly implemented in practice. This is to be appreciated. Except for a few procedures, the clock positions are also being followed properly. This really reduces the risk of musculoskeletal disorders to a great extent. But only some of the procedures (50%) have their patients' chair heights proper. In the rest of the procedures, an increase or decrease in the chair height by an inch or so was observed. This conditions are to be noted and improved. Also among interns, 8 o'clock position turned out to be the most preferred among all the clock positions (75%).

In Southern part of India, Muralidharan D et al., carried a study in the state of Andhra Pradesh and reported an incidence of 78% MSD. [1]Abduljabbar TA studied musculoskeletal disorders among dentists in Saudi Arabia and reported 82.9% of the responding dentists had pain or discomfort from the neck, shoulders, lower back or head. Chowanadisai S et al., carried a cross-sectional study regarding the occupational health problems faced by dentists in Thailand and found that musculoskeletal pain (78%) and percutaneous injury (50%) are the most often disorders faced by the dentists. Al Ali K et al., also carried a similar study among dentists in the United Arab Emirates and reported prevalence of musculoskeletal pain to be 68%.[1] Leggat PA et al.,reported 87.2% prevalence; neck being the most prevalent MSD during the previous 12 months followed by lower back and shoulder (53.3 per cent)[1].

CONCLUSION:

From this study, it is concluded that, though students initially find it difficult to follow the correct chair positions, it becomes implemented once they become interns. This greatly reduces musculoskeletal disorders and other discomforts in clinical practice. Though 8' o'clock position is preferred among both final year students and interns, its accordance while operating in different quadrants is to be considered.

REFERENCES:

1. H. S. Bedi.et al., Evaluation of Musculoskeletal Disorders in Dentists and Application of DMAIC Technique to Improve the Ergonomics at Dental Clinics and Meta-Analysis of Literature, Journal of Clinical and Diagnostic Research. 2015 Jun, Vol-9(6): ZC01-ZC03.

2. Forouzan Rafi et al., Prevalence of Upper Extremity Musculoskeletal Disorders in Dentists: Symptoms and Risk Factors, Journal of Environmental and Public Health Volume 2015, Article ID 517346.

3. Ratzon NZ et al., Musculoskeletal symptoms among dentists in relation to work posture, Work. 2000;15(3):153-158.

4. Hyun-Suk Park et al., Analysis of the risk factors of musculoskeletal disease among dentists induced by work posture, J. Phys. Ther. Sci. 27: 3651–3654, 2015.

Received on 24.03.2016 Modified on 21.04.2016

Research J. Pharm. and Tech. 2016; 9(6):722-724

DOI: 10.5958/0974-360X.2016.00137.2