Implementing magnification during pre-clinical training: Effects on procedure quality and working posture

Effect of loupe and microscope on dentists' neck and shoulder muscle workload during crown preparation

Although there is consensus among dentists that visual aids not only improve vision but also help improve posture, evidence is scarce. This study aimed to evaluate the effect of visual aids (loupe and microscope) on the muscle workload of dentists during crown preparation on dentiform first molars in each quadrant of a phantom head, considering dentists' muscles, patients' tooth positions and surfaces. Six right-handed dentists from a single tertiary hospital participated. Surface electromyography device recorded the muscle workload of the bilateral upper trapezius, sternocleidomastoid, cervical erector spinae, and anterior deltoid during crown preparation. The results showed significantly lower workload in all examined muscles when using a microscope compared to the naked eye (p < 0.05), whereas the loupe showed reduced workload in some specific muscles. The muscle with the highest workload for all visual aids was the cervical erector spinae, followed by the upper trapezius. When analyzed by tooth surface, while the loupe did not significantly reduce overall workload compared to the naked eye for each surface, the microscope significantly reduced workload for most surfaces (p < 0.05). Therefore, during crown preparation, the workload of the studied muscles can successfully be reduced with the use of a loupe or microscope.

Effects of magnification on restorative dental preparation performance: a scoping review and level of evidence mapping

OBJECTIVE

This scoping review aimed to identify and describe the available evidence on the effect of magnifying devices (loupe or microscope) on the performance of restorative dental preparations.

MATERIALS AND METHODS

This study was conducted according to the PRISMA-ScR guidelines for scoping reviews and registered on the INPLASY database. An electronic search was performed in four databases and Grey literature for articles published until November 2023. Eligibility criteria were determined using the PICOS strategy and comprised studies that evaluated the performance of magnification devices for restorative dental preparations. A bibliographic mapping of the evidence was conducted.

RESULTS

Sixteen studies met the inclusion criteria. Most of the studies (n = 12) compared the performance of dental preparations using magnification loupes vs. no magnification. The magnification for loupes and microscopes ranged from 2.5x to 4.0x and 6.4x to 10x, respectively. The use of magnifying loupes improved the performance of restorative preparations in 66.6% of the evaluated studies. However, when the magnifications were compared, the greater magnification provided by microscopes did not improve preparation performance compared to magnification loupes. Regarding the place of publication, the American continent concentrates the most significant number of evidence.

CONCLUSIONS

Although evidence for magnification improving the performance of dental preparations has increased over the last decade, basically only in vitro studies (most of which have taken place in the Americas) have been reported in the literature. The evidence suggests that magnification significantly improves restorative preparation performance when compared to non-magnification. However, higher magnifications (e.g., microscopes) do not appear to improve tooth preparation performance compared with lower magnification devices (e.g., magnification loupes).

CLINICAL RELEVANCE

Available evidence supports that using magnification can improve the performance of restored tooth preparations. However, high magnifications have no advantages over lower magnifications.

Magnification in preclinical procedures: effect on muscle activity and angular deviations of the neck and trunk

Objectives

This study aimed to assess the effects of different magnification systems on the angular deviations of the neck and trunk and the muscle activities of the upper back and neck during preclinical cavity preparation.

Methods

This was an experimental laboratory study, with the angular deviations from the neutral positions of the neck and trunk and the activities of the bilateral upper back (the descending and ascending trapezius) and neck (sternocleidomastoid) muscles as the dependent variables. The independent variables were the different magnification systems used (Simple, Galilean, and Keplerian loupes, with direct vision as the control) and prepared teeth (teeth 16, 26, 36, and 46). A dental mannequin phantom head with artificial resin teeth was used, and Class I cavity preparations for composite resin were performed on teeth 16, 26, 36, and 46 using a 1012 round diamond bur at low speed. To analyze the angular deviations, the postures adopted during the procedure were recorded using a tripod-mounted camera positioned to provide a lateral view of the operator. A trained researcher measured the angular deviations using the software entitled "Software for Postural Assessment"-SAPO (version 0.69). Bilateral muscle activity was assessed using surface electromyography. Descriptive statistical analysis was performed, and after verifying the assumptions of normality and homoscedasticity, two-way analysis of variance and the Tukey and Games-Howell post-hoc tests were used to compare the data (α=0.05).

Results

The angular deviation from the neutral position of the neck was found to be significantly higher during cavity preparations performed with the naked eye and the Simple loupe, irrespective of the prepared tooth. With regard to tooth location, the angular deviation of the neck was significantly greater during cavity preparation on teeth 16 and 26, and the angular deviation of the trunk was significantly greater during cavity preparation on tooth 26, regardless of the magnification system used. There were significant differences in right sternocleidomastoid muscle activity between the Simple, Galilean, and Keplerian loupes, with activity being the lowest for the Galilean loupe (p = 0.008). There were no significant differences in left sternocleidomastoid muscle activity between the loupes, regardless of the prepared tooth (p = 0.077). The activities of the bilateral descending trapezius and the right ascending trapezius muscles were significantly lower when the Galilean loupe was used (p < 0.010).

Conclusion

These results suggest that the Galilean loupe resulted in lower muscle activity in the neck and back regions and that the Galilean and Keplerian loupes resulted in less angular deviations of the neck and trunk during cavity preparation.

The impact of magnification on undergraduate dental students' performance during cavity preparations: A systematic review

PURPOSE/OBJECTIVES

Loupe magnification is a commonly utilized tool within dental education due to its proposed benefits of improving working posture, visual acuity, and procedural quality. Although procedural quality has been researched at the graduate level, literature encompassing the undergraduate level remains scarce. Therefore, this systematic review aims to critically assess the available literature to ascertain the effects of loupe magnification on the performance of undergraduate dental students' cavity preparations.

MATERIALS AND METHODS

A systematic search was conducted across electronic databases, including PubMed, MEDLINE via Ovid, The Cochrane Library for Cochrane Reviews, and Scopus, to identify relevant studies published from inception to February 15, 2023. We included English language studies that evaluated the effect of loupe magnification on the performance of undergraduate dental students in cavity preparations.

RESULTS

In total, six studies fulfilled the inclusion criteria. The outcomes assessed encompassed tooth preparation accuracy. Of these six articles, one was conducted on endodontic access cavity preparations, four on restorative cavity preparations, and one on nonstandard cavity preparation designs performed on acrylic blocs. Four articles determined that loupes positively impacted undergraduate students' performance in cavity preparations, while two articles established no significant difference in performance between loupes and naked-eye cavity preparations.

CONCLUSION

This systematic review suggests that loupe magnification positively impacts undergraduate dental students' performance in cavity preparations. However, the heterogeneity of the studies and the variations in methodologies limit the ability to draw definitive conclusions.

The effect of Galilean magnification loupes on the visual acuity and working distance of dental students

OBJECTIVE

This study aimed to evaluate the visual acuity and working distance of dental students using Galilean loupes at different magnification levels.

METHODS

The participants included 50 undergraduate dentistry students selected from each class in the second to fifth years (N = 200) of São Paulo State University, School of Dentistry, Araraquara. The response variables were (i) the working distance between the operator's eyes and the mouth of the dental phantom head, and (ii) visual acuity. The independent variables were the five levels of the Galilean magnification system (naked eye, Galilean loupe simulator without magnification, and Galilean loupes with 2.5×, 3.0×, or 3.5× magnification) and academic year. Visual acuity was measured using a miniature Snellen eye chart inserted into the Class I cavities of the maxillary molars. After verifying the assumptions of normality and sphericity, a mixed repeated measures analysis was performed (α = 0.05).

RESULTS

Statistical significance was found between the "magnification system" and "academic year" for visual acuity (p < 0.001). For the second-, fourth-, and fifth-year participants, there were no significant differences in visual acuity between the naked eye and different magnifications of the Galilean loupes, which were superior to and significantly different from that of the loupe simulator. For the working distance, statistical significance was observed in the interaction between "magnification system" and "academic year" (p = 0.008). For the third-, fourth-, and fifth-year participants, there was no significant difference in the working distance between the naked eye and different magnifications of the Galilean loupes, which were superior to and significantly different from that of the simulator.

CONCLUSION

It was concluded that the different magnification levels of the Galilean loupes did not influence the visual acuity or distance between the eyes of the operator and the mouth of the dental phantom head in the evaluated students.

Manual dexterity in dentistry: Development and evaluation of a preclinical training program

OBJECTIVES

The aim of this study was to develop and evaluate the effect of a manual dexterity training program on manual dexterity, perception of self-confidence, quality of cavity preparations, and ergonomic work posture of dental students prior to preclinical training.

METHODS

Students in the first year of the undergraduate dentistry program (N = 63) participated in this study. The program consisted of eight phases in which students performed different types of activities. The dependent variables were: manual dexterity assessed by the modified Dental Manual Dexterity Assessment; self-confidence to perform a preclinical procedure using the VAS scale; quality of Class I cavity preparation; angular deviation from the neutral position of the neck, trunk, wrist and distance between the student's eyes and the mannequin's tooth. These variables were evaluated at two different times: before and after the application of the program. The independent variable was the preclinical manual dexterity training program. After meeting the assumption of normality, the paired t-Student test was performed, the significance level was 5%.

RESULTS

The results showed a statistically significant difference in relation to manual dexterity (p < 0.001), self-confidence (p < 0.001), quality of cavity preparations (p < 0.001), distance from the eyes of the student/mannequin (p < 0.001), deviation angle of the neutral position of the trunk (p = 0.007) and wrists (p < 0.001), with better results in posttraining.

CONCLUSION

It was possible to conclude that, in general, the proposed training positively influenced the self-confidence, dexterity, quality of work, and ergonomics of the evaluated students.

Value of including loupes in prosthodontic and endodontic components of dental degrees: a systematic review

Background It is crucial dental students graduate with sound knowledge of endodontics and prosthodontics. The use of loupes is important for these due to their intricate nature, but there is currently no standardisation of curricula.Objective This systematic review investigates the value of including loupes in completing dental degrees and their benefits to dental students.Methods Literature was searched from inception to February 2022 in PubMed, Embase and Scopus. Articles included were primary studies of dental students studying endodontics or prosthodontics, which had outcomes related to the value of utilising loupes in learning, clinical application and ergonomics.Results A total of 1,489 articles were retrieved, of which 14 relevant articles were identified. These articles discussed student perceptions and the impact on visual acuity, ergonomic practices and dental procedures. Overall, students perceived that loupes increased self-confidence and allowed a greater operative view but were initially difficult to use. Using loupes resulted in greater visual acuity than no magnification and improved ergonomic practices by reducing neck angulation and improving posture. Students also received better grades when using loupes during cavity access preparation or root canal therapy.Conclusion The use of loupes by dental students can be beneficial if there is initial teaching on their use.

Do magnification loupes affect the precision of cavity preparations made by undergraduates? A randomized crossover study

Background

Evidence on the effect of magnification devices on procedure quality in restorative dentistry is scant. This study therefore aimed to assess, under simulated clinical conditions, if magnification loupes affect the quality of preparations carried out by undergraduate dental students.

Methods

59 undergraduate dental students underwent two visual acuity tests, based on which they were divided into a “low visual acuity group” (visus < 1) and a “good visual acuity group” (visus ≥ 1). In a randomized crossover experiment, participants performed a two-dimensional S and a three-dimensional O figure preparation with a dental handpiece on standardized acrylic blocs designed for preclinical restorative training. Each participant carried out the preparation tasks twice, once with magnification loupes (2.5×) and once without. Two blinded investigators independently evaluated parameters of preparation precision. Data were analyzed using Spearman rank correlation coefficients, intra-class correlation coefficients, and Wilcoxon rank-sum tests (α = 0.05).

Results

Participants from the “low visual acuity group” did not show a statistically significant improvement in accuracy when they used magnification loupes for the S figure preparation (p ≥ 0.0625). Participants from the “high visual acuity group” obtained a higher level of accuracy (p ≤ 0.0012) when they used magnification loupes for the S figure preparation. The use of magnification loupes had no statistically significant effect on the accuracy parameters of the O figure cavity preparations (p ≥ 0.1865). Participants with high visual acuity achieved only a marginally better accuracy than participants with a visus < 1.

Conclusions

This study suggests that loupes with 2.5× magnification increase the accuracy of two-dimensional preparations while they have no significant effect, favorable or otherwise, on the accuracy of complex, three-dimensional cavity preparations of untrained dental students.

Effect of magnification factor by Galilean loupes on working posture of dental students in simulated clinical procedures: associations between direct and observational measurements

Objectives

To determine the effect of different levels of Galilean loupe magnification on working posture as measured by compliance with ergonomic posture positions, angular deviation from the neutral position of the neck, and muscle activation in the neck and upper back region during simulated clinical conditions.

Methods

An experimental laboratory study was performed in which the dependent variables were compliance with ergonomic posture requirements while performing simulated restorative procedures in Restorative Dentistry, angular deviation from the neutral position of the neck, and muscle activation in the neck and upper back. The independent variable was the level of Galilean loupe magnification, which was tested at four levels (naked eye, 2.5× magnification, 3.0× magnification, and 3.5× magnification). The cavity preparations and Class I composite resin restorations were performed on artificial first molars on a mannequin in a dental chair. The Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP) was used for the postural analysis; as was an analysis of the angular deviation from the neutral position of the neck and surface electromyography. Working posture was recorded on video over the course of the procedure. Participants were filmed from three different angles. The Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP) assessed compliance with ergonomic posture requirements. A locally produced posture assessment software analyzed angular deviation. Surface electromyography bilaterally assessed activation of the sternocleidomastoid, descending trapezius and ascending trapezius muscles. Two-factor analysis of variance (ANOVA) and either Tukey's post-hoc test or the Games-Howell post-hoc test were performed (α = 0.05).

Results

During the cavity preparations and restorations, the use of Galilean loupes at all magnifications positively influenced working posture as measured by participants' compliance with ergonomic posture positions (p < 0.01) and neck angulation (p < 0.01); the use of these loupes did not affect muscle activation in the regions evaluated (p > 0.05).

Conclusion

The use of Galilean loupes had a positive effect on dental students' working posture during the restoration procedures performed.

Magnification effect on fine motor skills of dental students

OBJECTIVES

This study observed the effect of different magnification systems on dental students' real and perceived fine motor skills.

METHODS

This was a laboratory-based experimental study. Students in the fifth year of an undergraduate dentistry program (N = 92) participated in this study. The dependent variables were real motor skills, perceived motor skills and time required to complete the fine motor skills test. The independent variable was the use of a magnification system under four conditions. For each condition, the Dental Manual Dexterity Assessment was performed, which consisted of inserting the #3195FF bur into targets positioned on a Styrofoam plate. The accuracy of each penetration of the targets was scored, using a point system with a maximum possible score of 246 points. Students' perceived fine motor skills were assessed using a visual analog scale (VAS) that ranged from zero for no skills to ten for maximum skills. A descriptive statistical analysis and the repeated measures ANOVA were performed (α = 0.05).

RESULTS

The Galilean and Keplerian loupes were found to positively affect students' real fine motor skills (p<0.01); however, perceived fine motor skills and time were significantly better (p<0.01) under the naked eye.

CONCLUSIONS

Dental students' real fine motor skills were better when Galilean and Keplerian loupes were used, but the perceived fine motor skills were not.

Ergonomic working posture in simulated dental clinical conditions: effect of magnification on the operator's experience

Objectives

This study observed the effect of different magnification systems on working posture and neck angulation during cavity preparation procedures according to operator's experience.

Methods

This was a laboratory study. The response variables were the neck angulation and the working posture adopted during Class I cavity preparations (N = 640) that were performed under four conditions (unaided visualization, simple loupe, Galilean loupe and Keplerian loupe). Working postures were recorded and evaluated by the Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP). The two-factor ANOVA and Games-Howell post-hoc test were performed (α = 0.05).

Results

For all treated teeth it was observed higher posture scores and lowest neck angulations while using the Galilean and Keplerian loupes (p < 0.01). No correlations were found between operator's experience and working posture (p = 0.71-0.88).

Conclusion

It can be concluded that Galilean and Keplerian loupes helped operators to maintain an ergonomic posture and lower neck angulations for all teeth and the operator's experience provided better ergonomic posture for the mandibular teeth.

Development and validation of an instrument to assess adherence to occupational health protocols in dentistry

OBJECTIVES

The purpose of this study was the creation and validation of an instrument to evaluate adherence to occupational health protocols used in dentistry that arise from official regulations and international recommendations on infection control, biosafety, and occupational health in dentistry. Additionally, in May 2017 the effectiveness of the instrument was documented within the dental care clinics in the postgraduate area.

METHODS

The instrument was developed based on constructs of occupational health, infection control, and biosafety in dentistry, made up of 21 indicators of 5 dimensions called protocols. Using direct observation through 35 measurements during 1 week, adherence to occupational health protocols was evaluated in postgraduate residents within the clinical sections of endodontics/pediatric dentistry, periodontics, prosthodontics, and orthodontics.

RESULTS

The instrument presents an index of 0.88 in Cronbach's alpha analysis. There is a 34.4% adherence within the postgraduate dental clinic to the proposed occupational health protocols. The protocol with the highest adherence at 41.1% was the personal protection protocol. The periodontics section had a 52.9% observance of the proposed protocols and had the highest adherence to occupational health protocols.

CONCLUSIONS

The proposed instrument is valid and reliable to evaluate adherence to the proposed occupational health protocols within dental care clinics. Dental clinics must be inspected and evaluated to ensure adherence to infection control, biosafety, and occupational health protocols within routine dental practice.