The role of stereopsis (three-dimensional vision) in dentistry: review of the current literature

The value of stereoscopic three-dimensional vision on dental students' performance in a virtual reality simulator

PURPOSE/OBJECTIVES

The aim of this study was to quantitatively investigate the impact of stereoscopic three-dimensional (3D) vision on students' performance when compared with that of two-dimensional (2D) vision in a 3D virtual reality (VR) simulator.

METHODS

Twenty-four dental students (second- and fourth-year BDS) were assigned to perform three operative tasks under 3D and 2D viewing conditions on a Virteasy (HRV) simulator. Groups were crossed over and all students performed the same tasks under the alternate viewing conditions. The performance was evaluated by (1) accuracy, (2) outside target area removal, and (3) tooth cutting time, automatically using the generated feedback.

RESULTS

Twenty-one participants completed all sessions. The results revealed a statistically significant effect of 3D vision over 2D vision on students' performance in terms of accuracy (p = 0.035). Stereoscopic 3D vision showed significant effect on outside target area removal in the first task (p = 0.035). Tooth cutting time was the same under both conditions (p = 0.766). The findings revealed improvement in accuracy score and reduction in outside target area removal over the course of the experiment under both conditions. Comparing the difference in 3D effect in the early and advanced learning groups revealed no significant difference among the groups (p > 0.05).

CONCLUSION

Utilizing stereoscopic 3D vision in the training session improved students' perception of depth which led to more accurate tooth cutting within the target area, and less outside target area removal. However, 3D shows a limited impact on task completion time.

Association between stereoacuity and simulated clinical performance among dental students: an exploratory investigation

INTRODUCTION

Dentistry is a profession that requires a high level of the hand-eye coordination. Although considerable attention has been put on dental students' manual dexterity, little emphasis was made on students' visual competency as a variable influencing their competency. In this study, we aimed to assess the association between dental students' stereopsis and their pre-clinical performance.

METHODS

Dental students (n = 49) were required to perform the porcelain-fused-to-crown preparation for a lower first molar and an upper central incisor plastic teeth mounted on phantom heads. Performance was assessed by two faculty members based on two rubrics, which collectively included 11 assessment criteria. Afterward, students undertook a stereoacuity test using Randot stereotest. Stereopsis values greater than 40 arc/s were considered abnormal.

RESULTS

A significant negative correlation was seen between stereopsis scores and students' grades for the upper incisor (p < 0.01), but not for the lower molar. An association was also seen between abnormal stereopsis and students' poor performance in preparing the finish line of the incisor tooth (p = 0.024).

CONCLUSION

Abnormal stereopsis can impact dental students' performance, particularly when preparing teeth indirectly using a dental mirror. Dental educators should give attention to students' stereoacuity, in a manner similar to that given to students' manual dexterity.

The Best Dentistry Professional Visual Acuity Measured under Simulated Clinical Conditions Provides Keplerian Magnification Loupe: A Cross-Sectional Study

Visual acuity plays an important role in dentists’ vision in their daily clinical routine. This study aimed to determine dental students’ visual acuity without optical aids and when using magnification devices in simulated clinical conditions. The participants were forty-six students at the School of Dental Medicine with a visual acuity of 1.0 in decimal values or 100% in percentage. The central visual acuity was tested using a miniature Snellen eye chart placed in the molar cavity of a dental phantom, in simulated clinical conditions under five different settings (natural visual acuity, by applying head magnifying glasses x1,5 and binocular magnifying devices using Galileo’s x2,5/350 mm, Keplerx3,3/450 mm and Keplerx4,5/350 mm optical system). The Wilcoxon Signed Rank test shows that the distribution of measurements of the visual acuity undertaken by the application of magnifying devices (VNL, VGA2,5, VKP3,3, VKP4,5) contained higher values of visual acuity than those received by the use of natural vision (VSC) (p < 0.001 for the comparison to the VNL, VGA2,5, VKP3,3 and VKP4,5 groups). The highest and statistically most significant increase in visual acuity is achieved using the Keplerian telescope x4.5/350 mm. The application of magnifying devices provided dentistry professionals with better visual acuity, improving detail detection in an oral cavity during dental procedures by magnifying the oral structure. The use of magnification devices means much more precise work, decreases the operating time, improves posture and reduces muscle pain in the shoulder during dental treatment.

Drilling into the functional significance of stereopsis: the impact of stereoscopic information on surgical performance

Purpose

One suggested advantage of human binocular vision is the facilitation of sophisticated motor control behaviours via stereopsis – but little empirical evidence exists to support this suggestion. We examined the functional significance of stereopsis by exploring whether stereopsis is used to perform a highly skilled real‐world motor task essential for the occupational practice of dentistry.

Methods

We used a high fidelity virtual reality simulator to study how dentists’ performance is affected by the removal of horizontal retinal image disparities under direct and indirect (mirror) observation. Thirteen qualified dentists performed a total of four different dental tasks under non‐stereoscopic and stereoscopic vision conditions, with two levels of task complexity (direct and indirect observation) using a virtual reality dental simulator.

Results

Depth related errors were significantly higher under non‐stereoscopic viewing but lateral errors did not differ between conditions. Indirect observation led to participants drilling less of the target area compared to direct viewing, but this did not interact with the stereopsis manipulation.

Conclusions

The data confirm that dental practitioners use stereopsis and its presence results in improved dental performance. It remains to be determined whether individuals with stereo‐deficits can compensate adequately. Nevertheless, these findings suggest an important role for stereopsis within at least one occupation and justify the design of simulators with 3D displays.

Dressmakers show enhanced stereoscopic vision

The ability to estimate the distance of objects from one’s self and from each other is fundamental to a variety of behaviours from grasping objects to navigating. The main cue to distance, stereopsis, relies on the slight offsets between the images derived from our left and right eyes, also termed disparities. Here we ask whether the precision of stereopsis varies with professional experience with precise manual tasks. We measured stereo-acuities of dressmakers and non-dressmakers for both absolute and relative disparities. We used a stereoscope and a computerized test removing monocular cues. We also measured vergence noise and bias using the Nonius line technique. We demonstrate that dressmakers’ stereoscopic acuities are better than those of non-dressmakers, for both absolute and relative disparities. In contrast, vergence noise and bias were comparable in the two groups. Two non-exclusive mechanisms may be at the source of the group difference we document: (i) self-selection or the fact that stereo-vision is functionally important to become a dressmaker, and (ii) plasticity, or the fact that training on demanding stereovision tasks improves stereo-acuity.

A three dimensional view of stereopsis in dentistry

Stereopsis and its role in dental practice has been a topic of debate in recent editions of this Journal. These discussions are particularly timely as they come at a point when virtual reality simulators are becoming increasingly popular in the education of tomorrow's dentists. The aim of this article is to discuss the lack of robust empirical evidence to ascertain the relationship (if any) between stereopsis and dentistry and to build a case for the need for further research to build a strong evidence base on the topic.