Evaluation of tooth preparations for Class II cavities using magnification loupes among dental interns and final year BDS students in preclinical laboratory.

BACKGROUND: With the advances in optical technology, dentistry has been benefitted in varied ways over the ages. AIM: The aim of this study was to assess the effect of dental magnification loupes on psychomotor skill acquisition during preclinical operative exercise.
METHODS: 40 Typhodont teeth tooth no. 36 and 46 (Frasaco - U.S.A.) were mounted on the acrylic lower jaw base of Phantom Head. Teeth are prepared for class II (MO) cavity with conservative design using micromotor, mouth mirror and probe. Tooth no.36 was prepared using magnifying loupes while tooth no.46 was prepared without the loupes. Data collected was statistically analyzed using Chi square test.
RESULTS: The results revealed that tooth preparations were better under magnifying loupes as compared to those without it with statistically significant difference with Kappa value 0.64 for samples with loupes and 0.76 for without loupes. Moreover, the study samples expressed their difficulty for using the magnifying loupes during the tooth preparation since they were using it for the first time.
CONCLUSIONS: Magnifying loupes help the dental students to have better vision, thus improved dexterity with hands while preparing the tooth for restoration. However, dental students have to get adapted to the loupes for the ease of using loupes. Using loupes frequently may help them to get adapted to the loupes.

INTRODUCTION

Over the years the emphasis has been placed on conservative tooth preparation for restoring carious lesions. Dentists are focusing on more conservative designs of tooth preparations using modern optical aids for rendering better treatment to their patients.

Dentistry requires specific motor skills in association with good visual acuity. Dentistry has been greatly benefitted from the advances in optical technology such as magnification loupes and operating microscopes.[1] Though each of them have their own merits and demerits, they help in improving precision required beyond unaided vision. Magnification is useful at any age for a dentist to perform precisely restorative and endodontic procedures.

Magnification loupes are used in dentistry where increased visual performance is needed. Increased magnification and improved illumination of the operating field has many benefits for the operator, especially in endodontics.[2] The treatment quality improves through the usage of magnifying devices. The ability to work with a high level of accuracy and improved control reduces treatment time and reduces operator fatigue. According to various data, it has been found that every dental professional is at a potential risk for developing occupational musculoskeletal problems including the vision and posture in which the clinician sits. Slight modification in posture and vision through the usage of magnifying aids can improve the work efficiency of the clinician.[3]

Achromatic compound magnification loupes increase the size from ×2 to ×5, though magnification of ×2.5 to ×4 is generally used for restorative procedures.[4] The interest and use of loupes among dental practitioners and students appears to be growing.[5] Thus, the use of appropriate visual enhancement should be considered for all dental professionals to make the practice of dentistry more precise, easy, and more enjoyable; and thereby reducing the risk of musculoskeletal problems. The objective of this study was to evaluate clinical performance during tooth preparations for Class II cavities using magnification loupes among dental interns and final year BDS students in the preclinical laboratory.

MATERIALS AND METHODS

Forty Nos of Typhodont teeth #36 (20 Nos) and #46 (20 Nos) (Frasaco-USA) mounted on a lower acrylic jaw base of phantom head were prepared for a conservative mesio-occlusal (MO) Class II cavity design using micromotor, mouth mirror, explorer and periodontal probe in preclinical laboratory of conservative dentistry, and endodontics. The sample size comprised of dental interns and final year BDS students is divided equally into two groups, aged between 22 and 24 years. The study groups were asked to prepare two teeth each #36 was prepared using magnifying loupes (Heine [Germany], HR ×2.5, 420 mm/16”) while #46 was prepared without the loupes. The subjects were chosen having a normal vision or eye power <−3 diopters. Tooth preparations were done according to the descriptions.[6] The prepared cavity designs were evaluated by two senior faculty members for the quality. The rating scale: “Rating System for Quality Evaluation of Prepared Cavities” was followed for the evaluation of the cavity designs.[7]

A simple questionnaire was distributed to all the samples to evaluate the ease of adaptation with loupes. “How did you find working with the loupes?”

The ease was graded as follows:

Grade 1: Difficult.

Grade 2: Partially comfortable.

Grade 3: Easy/comfortable.

RESULTS

The results were analyzed using Chi-square test.

The cavity preparations were analyzed by two examiners and tested for inter examiner reliability. The results, which were analyzed using the “kappa value” showed us that there exists a difference between cavity preparations done under loupes and those done without it [Table 1]. Both the examiner's reliability of frequency in assessing cavity preparation favored the cavity preparations done under loupes as compared to those which were done without it [Tables 2 and 3]. Grade R, S, M were considered as satisfactory, and T and V were considered nonsatisfactory.[7]

Table 1

Inter examiner reliability to assess the cavity preparation

Table 2

Examiner 1 reliability of frequency in assessing cavity preparation

Table 3

Examiner 2 reliability of frequency in assessing cavity preparation

The data were analyzed for the satisfaction attained while doing cavity preparations for both, that is, cavity preparation done under loupes and without loupes. Satisfactory results were attained for the cavity preparations done using magnifying loupes [Tables 4 and 5].

Table 4

Satisfactory or Non satisfactory cavity preparation using loupes

Table 5

Satisfactory or Non satisfactory cavity preparation without using loupes

The study samples found that the tooth preparation done under loupes were difficult as compared to without loupes [Table 6].

Table 6

Ease of cavity preparation using loupes

DISCUSSION

Magnifying loupes have stepped as a boon in the dental market as the very fine details in cavity preparations can be visualized at a glance without straining the normal eyesight. Dimitrijevic et al. suggested routine testing of perceptual and visual abilities for the dental students and dentists so that difficulties can be identified and treated early in their dental education by examining dentist's and dental student's abilities to estimate small depths and distances. They found that individual perceptual abilities vary widely.[8] The quality of the dental work carried out by a dentist is dependent on experience, training, and manual dexterity, which are the a predictors for successful dental performance.[91011] However, dentistry also requires good perceptual and visual skills, not only for gathering clinical information, and diagnosis but more specifically for judging positions, distances, and the size of objects; and to improve clinical performance. Moreover, dental students may have visual or interpretative defects that would make acquisition of manual skills and interpretation of instruction difficult.[1213]

Hence, this study was planned to evaluate the quality of tooth preparation of MO Class II cavities prepared by final BDS students and interns using loupes and compare them with teeth prepared without loupes. Good eyesight is essential to providing the best dental care for patients. Literature has reported that some dental students had undetected visual defects that could potentially have influenced the performance of precise practical tasks and suggested that prospective dental students undertake visual screening tests prior to their acceptance into dental schools.[8] However, with the advent of loupes any slight discrepancy can be altered before any devastating effect (e.g., missed root canal in maxillary second premolars or undermined enamel walls in Class II cavity) emerges in near future, thus raising the standard of treatment quality provided.

This study was done on dental interns and final year students because they are not well versed with loupes and tooth preparation done by them will definitely guide us to advise regarding the usage of loupes. To standardize the difference in cavity preparations #36 and #46 were selected under direct vision, and MO cavity design was chosen. #36 was prepared using magnifying loupes while #46 was prepared under normal vision (i.e., without loupes).

The results revealed that cavity preparations are better under magnifying loupes than without loupes, with a statistically significant difference as per kappa values (0.64 with loupes and 0.76 without loupes) and Chi-square value (8.01). While evaluating the quality of tooth preparation around 80% of the cavity preparations was categorized “satisfactory” with the loupes as compared to 20%, which were categorized “nonsatisfactory.” This could be due to the use of loupes to provide greater detail of the oral cavity with better, clearer vision of the operating area, thereby reducing eyestrain, but do so without the need to be closer to the patient. During intense near visual work, the ciliary muscle of the eye, which produces accommodation (focusing) and the extra-ocular muscles, which converge the visual axis of each eye on to the object of interest, become fatigued. However, loupes magnify the operating site to ×2.5 to ×6. Hence, it may indirectly help to improve the quality of the work by improving the visibility of the operating site. It may also help to improve posture by subconscious attempts.[314] While comparing the ease of tooth preparation between lopes and normal vision without loupes, the study groups found working under normal vision are more comfortable than with loupes. This could be because of the relative inexperience of undergraduates with loupes.

Similar studies conducted by Buhrley et al., Farook et al. and Maggio et al. showed that working with the magnifying loupes is always better. Loupes not only influence the musculoskeletal health of the professional but also help improve the quality of the treatment.[2515]

As the age advances the visual acuity diminishes due to presbyopia. Magnifying loupes do play a major role in visualizing the minute details of the cavity without straining the eye muscles.[15] Every dental professional is at a potential risk for developing an occupational musculoskeletal injury. The vision and posture in which the clinician sits is strongly correlated, improving the work efficiency of the clinician. Eichenberger et al. evaluated the near visual acuity of 40 dentists and its improvement by using different magnification devices and they concluded that near visual acuity varies highly between individuals and decreases during the lifetime. Independent of age or natural vision, visual acuity can be significantly improved by using magnification devices.[16] Thus, by using the appropriate visual enhancement should be considered for all dental professionals to make the practice of dentistry easier, and more enjoyable, and to reduce the risk of musculoskeletal injury.

According to the results of the present study magnifying loupes, can be recommended to include in the undergraduate armamentarium.

CONCLUSIONS

Magnification loupes have significantly enhanced the quality of cavity preparations done by final year BDS students and interns during preclinical dental educational work. However, more practice with loupes is needed for convenience of its use.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Chart-1