Keywords
manual dexterity - Pegboard Test - O'Connor test - dental training
Introduction
Manual dexterity refers to the ability to manipulate items and execute exact movements
with coordination using one's hands. Possessing this competence is crucial for a dentist
to effectively perform dental procedures with exactness and precision, resulting in
conservative and aesthetically pleasing outcomes for patients.[1] Although the manual dexterity test is crucial for predicting the capacity of dental
students in preclinical work, not all dental schools include this test in their admission
process and are unaware of its value. This raises the question of whether manual dexterity
testing should be considered equally important as grade point average (GPA) in the
screening process, and whether it should be a universally adopted practice in all
dental schools globally.[2]
Novack and Turgeon conducted a study to determine whether the results of the dental
aptitude test can predict preclinical grades in dental school. They discovered that
students who scored 10 or higher on the manual dexterity test performed better in
both preclinical and clinical courses. Therefore, they recommend using these scores
as criteria in the admissions process. Furthermore, it was determined that raising
the cut-off score of the exam could effectively filter out students who have difficulties
in developing psychomotor skills.[3] The advantage of assessing and distinguishing the manual dexterity abilities of
each student is to tailor their clinical experience to their individual abilities.
In addition, students may experience dexterity concerns such as carpal tunnel syndrome,
manual stiffness, pain, trembling, and impaired hand–eye coordination, all of which
might impact the effectiveness of dental treatment.[1]
In general, dentists require remarkable precision skills on a very small scale to
carry out dental procedures. Therefore, it is crucial to include manual dexterity
assessments in all dental schools.[4]
Tests such as the Purdue Pegboard, O'Connor Finger Dexterity tests, and Functional
Dexterity tests are frequently employed to assess the skills of dentistry students.[4] In 2022, Saeed et al utilized the Purdue Pegboard test and the O'Connor Tweezer
test to assess the manual skill of dental students in their preclinical year. It was
shown that both direct and indirect manual abilities showed a considerable increase
with time, and gender did not have any impact on the extent of improvement. Furthermore,
the utilization of indirect vision led to a decrease in student performance compared
with the use of direct vision. Their findings suggest that additional training over
a period of time can potentially improve manual dexterity.[5]
Students' manual dexterity is influenced by their engagement in many activities, including
painting, knitting, and playing musical instruments. Johnson et al suggest that if
participants do not engage in these activities, it may indicate a slower development
of their dental fine motor skills. To prevent these students from lagging behind their
peers during simulation clinics, it is crucial to offer them guidance and hands-on
tutorial instruction.[6] Multiple studies have established a connection between the lack of engagement in
these activities before attending dental school and worse scores on psychomotor tests.
This highlights the significance of hobbies and tasks such as jewelry-making that
can enhance manual dexterity.[7]
The objective of this study is to investigate whether engaging in preclinical practice
in restorative laboratories, which involves the utilization of dental hand instruments
with both direct and indirect vision, has an impact on the manual dexterity of dental
students. The assessment of manual dexterity will be conducted on year 1 dentistry
students during the spring semester of 2023, utilizing the Purdue Pegboard Test and
the O'Connor Test. The assessments will be repeated with the same students at the
commencement of the spring semester in the year 2024. Students' manual dexterity is
influenced by their engagement in various hobbies, like painting, crocheting, and
playing musical instruments, as previously noted. Therefore, this study will also
investigate the impact of these attributes on their manual dexterity performance.
Materials and Methods
Participants
Before collecting data, the University Research Ethics Committee granted authorization
for this project with the approval number (REC-23-01-23-01-S). After providing a thorough
description of the study's objective and emphasizing the significance of keeping the
data anonymous, we obtained the informed consent of the participants. The sample size
(n) was obtained using G*Power version 3.1 software. The t-test statistical family parameter was used, assuming a medium effect size of 0.5,
an α error probability of 0.05, and a study power of 0.9. The minimum sample size was
45. Hence, a total of 45 dental students, who were in their first year at the university,
voluntarily agreed to take part in this study. They were then monitored until the
second semester of the next academic year. Prior to commencing the trial, all participants
provided their signature on an informed consent document.
Purdue Pegboard Test
The test comprises a board with two columns of holes. At the distal end of the board,
there are four cups. These cups consist of a right cup and a left cup, each carrying
25 pins. Additionally, there is a cup with washers and a cup with collars. There are
four tasks that need to be completed in this test. The initial three activities necessitate
the insertion of pins into holes on the board within a time limit of 30 seconds, while
the final task necessitates a time limit of 60 seconds. The score of every task is
determined by the number of pins that are inserted. The roles display disparities
in the following manner: The third task was completed by first using the dominant
hand and then the nondominant hand, involving both hands in the process. This required
holding one pin in each hand and inserting them simultaneously into two corresponding
holes.
The fourth task is the Purdue direct assembly. During the assembly process, the participant
consistently utilizes both hands to put together four components. The process begins
with inserting a pin, followed by threading a washer and a collar, and concludes with
another washer. Following the completion of the four tasks using direct vision, the
subjects proceeded to execute the same four tasks utilizing indirect vision.
The participant sequentially threads a washer and a collar, assembles four components
(commencing with a pin), and concludes by threading another washer, all while maintaining
continuous use of both hands. After completing the four activities using direct vision,
the individuals proceeded to do the same four tasks using indirect vision ([Fig. 1]).
Fig. 1 Purdue Pegboard Test has four tasks. First and second tasks are done by using the
dominant and nondominant hands (A) and then by using both hands (B) and the fourth task (assembly task) (C). These tasks should be conducted twice, first by using direct vision (A–C) and then indirect vision using mirror and a blackboard shield to hide the board
test (D).
O'Connor Tweezer Test of Dexterity
This test consists of a board with 100 holes and a cup with 100 pins. The participant
meticulously positions each of the 100 pins using tweezers and their dominant hand.
During this examination, O'Connor Tweezers were used for both direct and indirect
vision. The duration required to insert each pin into a hole was established as 5 minutes,
and the score was computed accordingly ([Fig. 2]).
Fig. 2 (A, B) Direct and indirect visions for O'Connor Dexterity Test.
To establish indirect vision for both the Purdue and O'Connor tests, a blackboard
shield is used to cover the test board. This prevents participants from directly seeing
the board and allows them to complete activities using a mirror. The assessment was
conducted in a calm, quiet, and meticulously maintained environment to eliminate any
potential distractions. Prior to commencing each level, all participants were provided
with consistent and clear direction by a single instructor via written notes. Students
were given the freedom to take brief breaks, enabling them to extend their legs by
moving around the classroom in between tasks. Evaluations were performed at two specific
points in time: T0, prior to the preclinical training laboratory, and T1, following
the preclinical training laboratory, which occurred 7 months after T0.
Questionnaire
We have utilized a validated questionnaire that was previously employed in another
investigation.[6]
The questionnaire consists of 25 questions pertaining to gender, hands-on activities,
extra dental training, artistic skill, psychomotor skills, outdoor activities, and
prior expertise in the participant's dental skills. The background of each participant
in terms of gender, age, and training time in the simulation preclinical training
laboratory is obtained through four questions. Fill-in section at the end of the question
was provided to write how many hours they spent, dominant hand (right or left). The
remaining 20 questions pertain to the extent of training and lifelong engagement with
diverse physical activities prior to dental school. These activities encompass visualization
as well as the development of both gross and fine motor skills, such as artistic drawing,
painting, arts and crafts, participation in boy and girl scouts, playing musical instruments,
carpentry, car repair, team and individual sports, hunting, fishing, cooking training,
and working in dental or medical offices or laboratories. For each activity, participants
need to provide a rating from 0 to 4, with 0 indicating no involvement and 4 indicating
the highest level of involvement, based on their lifelong participation. At the conclusion
of the survey, there was a place where students could provide additional activities
that were not included in the provided list, as depicted in [Fig. 3].
Fig. 3 A questionnaire composed of 26 questions about gender, dominant hand, extra dental
training, artistic skills, psychomotor skills, outdoor activities, and prior experience
on participants' dental skills.
Statistical Analysis
Quantitative variables are represented by means and standard deviation (SD), while
qualitative variables are presented as counts in percentages. To assess normality,
the Shapiro–Wilk test was employed. Spearman's correlation was one of the nonparametric
tests utilized to examine the relationship between the survey domain and the skills
measurements of the participants. For normal and nonnormal variables, we compared
pre- and post-participant skill measurements using the paired t-test and Wilcoxon's rank test, respectively. Utilizing the Spearman correlation coefficient
(rho), both the strength and the direction of the relationship were determined. The
investigators employed multivariate linear regression analysis to predict the impact
of prior experience, artistic skill, psychomotor skills, hands-on activities, and
artistic skill on the dental skills of the participants. Differences between groups,
correlations, and effects of predictors were considered statistically significant
at p < 0.05. Statistical analysis was performed using the statistical package for the
social sciences (SPSS) computer software (version 27), IBM software, United States.
Results
-
1. The study included a cohort of 45 dental students, with females comprising a greater
proportion than males (57.8 vs. 42.2%). Approximately 71.1% of the participants were
right-handed, whereas the remaining 28.9% were left-handed. Just 35.6% of the participants
dedicated extra hours to improve their manual dexterity ([Table 1]).
Table 1
Descriptive statistics of gender, hands-on activities, and extra dental training
|
Items
|
No. (count)
|
%
|
|
Gender
|
|
Male
Female
|
19
26
|
42.2
57.8
|
|
Dominant hand (hands-on activities)
|
|
Right
Left
|
32
13
|
71.1
28.9
|
|
Simulating laboratory training (extra dental training)
|
|
During laboratory
Laboratory + after working hours
|
29
16
|
64.4
35.6
|
Applying the Shapiro–Walik test to the 20 variables under examination, it was found
that 12 of them exhibited nonnormal distribution with a significance level of p < 0.05. Conversely, eight variables showed normal distribution, as indicated in [Table 2]. Out of the 16 factors tested in the Purdue Pegboard Test, 9 showed statistical
significance, with p-values ranging from 0.002 to 0.047. In the O'Connor Tweezer Test, three out of four
variables showed statistical significance, with p-values ranging from <0.001 to 0.013.
Table 2
Test of normality using the Shapiro–Wilk test
|
Test
|
Statistics
|
Significance
|
|
Direct visual test of the right hand before training
|
0.965
|
0.191
|
|
Direct visual test of the right hand after training
|
0.968
|
0.247
|
|
Direct visual test of the left hand before training
|
0.909
|
0.002[a]
|
|
Direct visual test of the left hand after training
|
0.946
|
0.036
|
|
Direct visual test of both hands before training
|
0.949
|
0.047[b]
|
|
Direct visual test of both hands after training
|
0.907
|
0.002[a]
|
|
Direct visual test of assembly before training
|
0.944
|
0.031[b]
|
|
Direct visual test of assembly after training
|
0.959
|
0.108
|
|
Indirect visual test of the right hand before training
|
0.972
|
0.343
|
|
Indirect visual test of the right hand after training
|
0.960
|
0.120
|
|
Indirect visual test of the left hand before training
|
0.925
|
0.006[a]
|
|
Indirect visual test of the left hand after training
|
0.965
|
0.183
|
|
Indirect visual test of both hands before training
|
0.947
|
0.04[b]
|
|
Indirect visual test of both hands after training
|
0.942
|
0.026[b]
|
|
Indirect visual test of assembly before training
|
0.930
|
0.009[a]
|
|
Indirect visual test of assembly after training
|
0.932
|
0.011[b]
|
|
Direct visual test O'Connor before training
|
0.980
|
0.602
|
|
Direct visual test O'Connor after training
|
0.847
|
< 0.001[a]
|
|
Indirect visual test O'Connor before training
|
0.869
|
< 0.001[a]
|
|
Indirect visual test O'Connor after training
|
0.934
|
0.013[b]
|
a
p < 0.01.
b
p < 0.05.
[Table 3] presents the outcomes of the laboratory training pertaining to the manual dexterity
skills of the students. Following dental preclinical laboratory training (T0), participants'
skills in all parameters, including direct and indirect visual testing of the O'Connor
Tweezers Test and the Purdue direct and indirect visual tests of the right, left,
both hands, and assembly, increased significantly. Students' performance on the Purdue
right-hand direct visual test (DVT) improved significantly (p = 0.014), from ∼14 pins placed at T0 to 16 pins placed at T1. This finding aligns
with the results of the Purdue right-hand indirect visual test (IVT), as the number
of pins affixed at T1 increased from 13 to 15 in a statistically significant way (p < 0.001).
Table 3
Comparison between the participants' skills at the beginning (T0) and after 7 months
of the preclinical training course (T1)
|
Parameter
|
Pre-training (mean ± SD)
|
Post training (mean ± SD)
|
Test statistics value
|
p-Value
|
|
Direct visual test of the right-hand
|
14.69 ± 1.86
|
15.67 ± 2.13
|
2.568
|
0.014[a]
|
|
Direct visual test of the left-hand
|
13.00 ± 1.55
|
14.20 ± 1.94
|
3.550
|
< 0.001[a]
|
|
Direct visual test of both hands
|
10.93 ± 1.57
|
11.69 ± 1.77
|
2.431
|
0.015[a]
|
|
Direct visual test assembly
|
7.40 ± 1.50
|
8.56 ± 1.78
|
2.882
|
0.004[a]
|
|
Indirect visual test of the right-hand
|
5.60 ± 2.41
|
9.78 ± 1.86
|
9.335
|
< 0.001[a]
|
|
Indirect visual test of the left-hand
|
4.82 ± 2.27
|
9.29 ± 1.87
|
5.664
|
< 0.001[a]
|
|
Indirect visual test of both hands
|
4.02 ± 1.88
|
6.11 ± 1.42
|
4.604
|
< 0.001[a]
|
|
Indirect visual test assembly
|
4.22 ± 1.36
|
5.13 ± 1.49
|
3.254
|
0.001[a]
|
|
Direct visual test O'Connor
|
76.20 ± 12.74
|
87.64 ± 13.13
|
4.324
|
< 0.001[a]
|
|
Indirect visual test O'Connor
|
15.64 ± 12.74
|
26.78 ± 10.41
|
4.971
|
< 0.001[a]
|
Notes: Statistical analysis was done using paired t-test or Wilcoxon's test according to normal distribution analysis by Shapiro–Wilk
test. The test statistics is t-value for the paired t-test or z-value for the Wilcoxon test.
a Significantly different at p < 0.05 (n = 45).
The mean number of pins placed during the O'Connor Tweezers Test with direct vision
was ∼76 over the course of 5 minutes. At T1, this number increased significantly (p < 0.001) to 88 out of 100. Additional analysis reveals that the O'Connor Indirect
Test improved significantly (p < 0.001) from 16 at T0 to 27 pins at T1.
During the Purdue Pegboard Test, females exhibited higher mean differences than males
when both hands and the right hand were used in direct and indirect visual tasks.
Furthermore, females exhibited higher scores in the left-hand IVT test (5.15 ± 2.56)
and indirect assembly test (1.15 ± 1.59) compared with males (3.53 ± 2.57 and 0.58 ± 1.64),
respectively. In general, females had better average scores in all indirect visual
tests compared with males. In contrast, males exhibited greater mean differences than
females in the left-hand DVT test (1.58 ± 2.32 vs. 0.92 ± 1.76) and direct visual
assembly test (1.32 ± 2.79 vs. 1.04 ± 2.25). However, the only test that demonstrated
a statistically significant difference (p < 0.05) in skill outcomes between males and girls is the (IVT) of the left hand,
with a p-value = 0.04. These findings suggest that females outperform males in the Purdue
IVT of the left hand, with a statistically significant difference in scores.
Concerning the O'Connor's test, the direct vision test revealed a slightly greater
mean difference value in males (72.05 ± 16.10) compared with females (71.96 ± 16.15).
On the other hand, females exhibited higher average difference values in the indirect
vision test than males (12.57 ± 10.51 vs. 9.16 ± 12.69). Nevertheless, the O'Connor
Tweezer Test reveals no significant difference in skill results between males and
females (p > 0.05) ([Table 4]).
Table 4
Descriptive statistics of participants' skills (difference between pre- and post-measurements)
in relation to gender
|
Parameter
|
Male (mean ± SD)
|
Female (mean ± SD)
|
p-Value
|
|
Direct visual test of the right-hand
|
0.80 ± 2.72
|
1.12 ± 2.47
|
0.69
|
|
Direct visual test of the left-hand
|
1.58 ± 2.32
|
0.92 ± 1.76
|
0.30
|
|
Direct visual test of both hands
|
0.47 ± 1.98
|
0.96 ± 1.87
|
0.40
|
|
Direct visual test assembly
|
1.32 ± 2.79
|
1.04 ± 2.25
|
0.72
|
|
Indirect visual test of the right-hand
|
4.42 ± 3.54
|
4.00 ± 2.59
|
0.66
|
|
Indirect visual test of the left-hand
|
3.53 ± 2.57
|
5.15 ± 2.56
|
0.04[a]
|
|
Indirect visual test of both hands
|
1.84 ± 2.14
|
2.27 ± 2.53
|
0.54
|
|
Indirect visual test assembly
|
0.58 ± 1.64
|
1.15 ± 1.59
|
0.25
|
|
Direct visual test O'Connor
|
72.05 ± 16.10
|
71.96 ± 16.15
|
0.98
|
|
Indirect visual test O'Connor
|
9.16 ± 12.69
|
12.57 ± 10.51
|
0.34
|
a
p < 0.05.
Dominant Hand Differences
The mean differences in the DVT of the right hand were higher in right-handed participants
(1.00 ± 2.55) compared with left-handed ones (0.92 ± 2.66). Interestingly, the left-handed
participants (2.77 ± 1.92) exhibited more pronounced differences compared with the
right-handed participants (0.56 ± 1.70) while utilizing DVT of their left hands. This
pattern also holds true when both hands were examined, with left-handed subjects (1.23 ± 1.69)
showing greater differences than right-handed participants (0.56 ± 1.98). Left-handed
participants had significantly higher mean difference values in both direct and indirect
assembly tests. However, the mean differences were higher in right-handed participants
when they were assessed using the direct O'Connor's test (72.22 ± 14.56 vs. 71.46 ± 19.58)
and the indirect O'Connor's test (11.94 ± 8.96 vs. 9.15 ± 16.40). The only test that
exhibited a significant difference in skill results between individuals who are right-handed
and those who are left-handed was the DVT of the left hand. Furthermore, the scores
of left-handed individuals in the Purdue DVT of the left hand are considerably greater
compared with those of right-handed participants (p-value = 0.0004). The results of the right-hand DVT suggest that there was no statistically
significant difference in scores between individuals who are right-handed and those
who are left-handed (p = 0.92; [Table 5]).
Table 5
Descriptive statistics of participants' skills (difference between pre- and post-measurements)
in relation to dominant hands used
|
Parameter
|
Right (mean ± SD)
|
Left (mean ± SD)
|
p-Value
|
|
Direct visual test of the right-hand
|
1.00 ± 2.55
|
0.92 ± 2.66
|
0.92
|
|
Direct visual test of the left-hand
|
0.56 ± 1.70
|
2.77 ± 1.92
|
0.0004[a]
|
|
Direct visual test of both hands
|
0.56 ± 1.98
|
1.23 ± 1.69
|
0.29
|
|
Direct visual test assembly
|
1.00 ± 2.32
|
1.54 ± 2.84
|
0.51
|
|
Indirect visual test of the right-hand
|
3.97 ± 2.91
|
4.69 ± 3.27
|
0.47
|
|
Indirect visual test of the left-hand
|
4.81 ± 2.90
|
3.62 ± 1.76
|
0.18
|
|
Indirect visual test of both hands
|
2.16 ± 2.33
|
1.92 ± 2.53
|
0.76
|
|
Indirect visual test assembly
|
0.88 ± 1.60
|
1.00 ± 1.73
|
0.82
|
|
Direct visual test O'Connor
|
72.22 ± 14.56
|
71.46 ± 19.58
|
0.89
|
|
Indirect visual test O'Connor
|
11.94 ± 8.96
|
9.15 ± 16.40
|
0.46
|
Note: (n = 45), 32 right, and 13 left.
a
p < 0.001.
Twenty-nine students participated in laboratory training and 16 students completed
laboratory training with extra after-work training. There was a noticeable improvement
in the results of the DVT of the left hand among participants with extra training
(2.31 ± 2.21) compared with only laboratory training (0.59 ± 1.64). This pattern is
also present in the DVT of both hands (1.13 ± 1.74 vs. 0.55 ± 1.99), DVT assembly
(1.25 ± 2.35 vs. 1.10 ± 2.57), IVT of the left hand (5.19 ± 2.93 vs. 4.07 ± 2.46),
IVT of both hands (2.13 ± 2.78 vs. 2.07 ± 2.15), IVT assembly (1.19 ± 2.01 vs. 0.76 ± 1.38),
and IVT O'Connor (12.25 ± 16.28 vs. 10.52 ± 7.98). The only variables that did not
show improvement in scores were the DVT of the right hand, the IVT of the right hand,
and the DVT of the O'Connor Test ([Table 6]). Nonetheless, the only test that showed a statistically significant difference
in skill results after extra laboratory training was the DVT of the left hand (p = 0.0048).
Table 6
Descriptive statistics of participants' skills (difference between pre- and post-measurements)
in relation to extra dental training
|
Parameter
|
During laboratory (mean ± SD)
|
Laboratory + after working hours (mean ± SD)
|
p-Value
|
|
Direct visual test of the right-hand
|
1.10 ± 2.64
|
0.75 ± 2.46
|
0.66
|
|
Direct visual test of the left-hand
|
0.59 ± 1.64
|
2.31 ± 2.21
|
0.0048[a]
|
|
Direct visual test of both hands
|
0.55 ± 1.99
|
1.13 ± 1.74
|
0.33
|
|
Direct visual test assembly
|
1.10 ± 2.57
|
1.25 ± 2.35
|
0.85
|
|
Indirect visual test of the right-hand
|
4.31 ± 2.90
|
3.94 ± 3.26
|
0.70
|
|
Indirect visual test of the left-hand
|
4.07 ± 2.46
|
5.19 ± 2.93
|
0.18
|
|
Indirect visual test of both hands
|
2.07 ± 2.15
|
2.13 ± 2.78
|
0.94
|
|
Indirect visual test assembly
|
0.76 ± 1.38
|
1.19 ± 2.01
|
0.40
|
|
Direct visual test O'Connor
|
72.69 ± 16.55
|
70.75 ± 15.23
|
0.70
|
|
Indirect visual test O'Connor
|
10.52 ± 7.98
|
12.25 ± 16.28
|
0.63
|
Note: (n = 45), 29 during laboratory, and 16 laboratory + after working hours.
a
p < 0.001, domains were mildly engaged with by the participants as they ranged between
0.80 and 1.59.
The questionnaire in [Table 7] was used to assess four dimensions of participants' skills. The responses were classified
as “not engaged” when the Likert score fell within the range of 0 to 0.79. They were
classified as “mildly engaged” when the score was between 0.80 and 1.59, and as “moderately
engaged” when it fell within the range of 1.60 to 2.39. Finally, responses were classified
as “actively engaged” when the score ranged from 4.20 to 5.0.
Table 7
Means and standard deviation of skills domains of the survey
|
Domain
|
Mean ± SD
|
|
Artistic skills
|
1.23 ± 1.08
|
|
Psychomotor skills
|
0.84 ± 0.99
|
|
Outdoor activities
|
0.87 ± 0.98
|
|
Prior experience
|
1.11 ± 0.91
|
To be more precise, around 43.7% of the participants did not possess creative talents,
whereas only 11.65% of the participants were highly involved in artistic skills. Approximately
two-thirds of the participants lacked psychomotor skills, with an average score of
62.13 ± 14.94. Only 5% of the individuals demonstrated a high level of engagement
in this particular skill set.
Over 50% of the participants did not engage in any outside activities such as fishing,
sports, woodworking, or hunting. Only 5% of the participants were highly engaged in
outdoor activities.
In terms of previous dental experience, 64.3% of the participants reported having
no prior experience, while just 10% indicated a high level of engagement with dental
procedures in the past.
[Figs. 4] to [7] demonstrate the frequency distribution of the aforementioned skills.
Fig. 4 Frequency distribution of artistic skills.
Fig. 5 Frequency distribution of psychomotor skills.
Fig. 6 Frequency distribution of outdoor activities.
Fig. 7 Frequency distribution of prior dental experience.
The relationship between the survey domains and the skills of the participants, as
measured by the difference between the pre- (T0) and post-measurements (T1), is displayed
in [Table 8]. There is a positive correlation between artistic skills and psychomotor skills
(r = 0.443; p = 0.002) as well as past experience (r = 0.443; p = 0.002). Psychomotor skills exhibit a positive correlation with artistic skills
(r = 0.443; p = 0.002), outdoor activities (r = 0.761; p = 0.000), and past experience (r = 0.377; p = 0.011). Engaging in outdoor activities is positively correlated with the development
of psychomotor skills (r = 0.761; p < 0.001) and is also influenced by prior experience (r = 0.463; p = 0.001). Previous experiences had a favorable correlation with artistic skills (r = 0.443; p = 0.002), psychomotor skills (r = 0.377; p = 0.011), and outdoor activities (r = 0.463; p = 0.001). The psychomotor activities had a highly significant positive link with
outdoor activities, as indicated by a strong correlation coefficient (r = 0.761).
Table 8
Correlation between survey domains and participants' skills (difference between pre-
and post-measurements)
|
Artistic skills
|
Psychomotor skills
|
Outdoor activities
|
Prior experience
|
|
Artistic skills
|
Correlation coefficient (rho)
|
|
|
|
|
|
p-Value
|
|
|
|
|
|
Psychomotor skills
|
Correlation coefficient (rho)
|
0.443
|
|
|
|
|
p-Value
|
0.002[a]
|
|
|
|
|
Outdoor activities
|
Correlation coefficient (rho)
|
0.334
|
0.761
|
|
|
|
p-Value
|
0.025[a]
|
< 0.001[a]
|
|
|
|
Prior experience
|
Correlation coefficient (rho)
|
0.443
|
0.377
|
0.463
|
|
|
p-Value
|
0.002[a]
|
0.011[a]
|
0.001[a]
|
|
|
Direct visual test of the right-hand
|
Correlation coefficient (rho)
|
0.109
|
- 0.078
|
- 0.094
|
0.037
|
|
p-Value
|
0.478
|
0.609
|
0.538
|
0.810
|
|
Direct visual test of the left-hand
|
Correlation coefficient (rho)
|
− 0.021
|
− 0.047
|
− 0.055
|
− 0.042
|
|
p-Value
|
0.892
|
0.762
|
0.721
|
0.785
|
|
Direct visual test of both hands
|
Correlation coefficient (rho)
|
0.100
|
− 0.060
|
− 0.100
|
0.047
|
|
p-Value
|
0.515
|
0.695
|
0.514
|
0.757
|
|
Direct visual test assembly
|
Correlation coefficient (rho)
|
0.140
|
− 0.103
|
− 0.080
|
0.029
|
|
p-Value
|
0.358
|
0.499
|
0.599
|
0.851
|
|
Indirect visual test of the right-hand
|
Correlation coefficient (rho)
|
− 0.127
|
0.038
|
0.048
|
0.012
|
|
p-Value
|
0.405
|
0.807
|
0.754
|
0.937
|
|
Indirect visual test of the left-hand
|
Correlation coefficient (rho)
|
0.174
|
− 0.104
|
− 0.177
|
0.108
|
|
p-Value
|
0.254
|
0.496
|
0.245
|
0.481
|
|
Indirect visual test of both hands
|
Correlation coefficient (rho)
|
0.101
|
− 0.062
|
− 0.157
|
− 0.037
|
|
p-Value
|
0.510
|
0.686
|
0.304
|
0.807
|
|
Indirect visual test assembly
|
Correlation coefficient (rho)
|
− 0.137
|
− 0.224
|
− 0.135
|
0.163
|
|
p-Value
|
0.369
|
0.140
|
0.375
|
0.285
|
|
Direct visual test of O'Connor
|
Correlation coefficient (rho)
|
− 0.128
|
0.038
|
0.041
|
− 0.035
|
|
p-Value
|
0.403
|
0.807
|
0.791
|
0.821
|
|
Indirect visual test of O'Connor
|
Correlation coefficient (rho)
|
− 0.131
|
− 0.107
|
0.037
|
− 0.038
|
|
p-Value
|
0.392
|
0.483
|
0.809
|
0.802
|
Note: Spearman's correlation was used.
a Significant correlation at p < 0.05.
Nevertheless, the majority of correlation coefficients between visual test performance
and examined domains such as artistic skills, psychomotor skills, outdoor activities,
and prior experience are nearly nil, suggesting a weak or nonexistent association.
Furthermore, there was no significant link between the skills categories and the participants'
direct and indirect visual assessments (p > 0.05). This implies that performance on visual tests is not significantly affected
by criteria such as artistic skill, motor skills, outdoor activities, or previous
experience, as indicated by the survey.
A multivariate linear regression analysis was performed to examine the impact of predictors
on direct visual tests, namely, the difference between pre- and post-measurements.
The predictors, such as gender, dominant hand, extra dental laboratory training, artistic
skills, psychomotor skills, outdoor activities, and prior experience, did not have
a significant impact on the results of the direct visual test on the right hand, both
hands, assembly, and O'Connor test (p > 0.05; [Table 9]).
Table 9
Multivariate linear regression analysis to study the effect of predictors on the direct
visual test (difference between pre- and post-measurements)
|
Predictors
|
Unstandardized coefficients
|
Standardized coefficients
|
t-Value
|
p-Value
|
R
2
|
|
Right hand
|
Male
|
− 0.001
|
0.000
|
0.001
|
1.000
|
0.048
|
|
Right dominant hand
|
− 0.453
|
-0.081
|
0.428
|
0.671
|
|
Laboratory + after working hours
|
− 0.932
|
0.177
|
0.870
|
0.390
|
|
Artistic skills
|
0.481
|
0.203
|
0.905
|
0.371
|
|
Psychomotor skills
|
− 0.826
|
− 0.321
|
0.625
|
0.536
|
|
Outdoor activities
|
0.104
|
0.040
|
0.086
|
0.932
|
|
Prior experience
|
0.291
|
0.104
|
0.453
|
0.653
|
|
Left hand
|
Male
|
0.414
|
0.102
|
0.633
|
0.530
|
0.360
|
|
Right dominant hand
|
− 1.648
|
− 0.347
|
2.406
|
0.021[a]
|
|
Laboratory + after working hours
|
1.435
|
0.344
|
2.066
|
0.046[a]
|
|
Artistic skills
|
− 0.176
|
− 0.094
|
0.512
|
0.612
|
|
Psychomotor skills
|
0.253
|
0.125
|
0.296
|
0.769
|
|
Outdoor activities
|
− 0.633
|
− 0.307
|
0.804
|
0.427
|
|
Prior experience
|
0.115
|
0.052
|
0.275
|
0.785
|
|
Both hands
|
Male
|
− 0.474
|
− 124
|
0.646
|
0.522
|
0.100
|
|
Right dominant hand
|
− 0.957
|
− 0.230
|
1.246
|
0.221
|
|
Laboratory + after working hours
|
0.057
|
0.014
|
0.073
|
0.942
|
|
Artistic skills
|
0.269
|
0.152
|
0.696
|
0.491
|
|
Psychomotor skills
|
− 0.237
|
− 0.123
|
0.247
|
0.807
|
|
Outdoor activities
|
− 0.267
|
− 0.137
|
0.303
|
0.764
|
|
Prior experience
|
0.154
|
0.074
|
0.330
|
0.743
|
|
Assembly
|
Male
|
0.716
|
0.145
|
0.739
|
0.464
|
0.061
|
|
Right dominant hand
|
− 0.616
|
− 0.114
|
0.607
|
0.548
|
|
Laboratory + after working hours
|
− 0.248
|
− 0.049
|
0.241
|
0.811
|
|
Artistic skills
|
0.191
|
0.083
|
0.375
|
0.710
|
|
Psychomotor skills
|
− 0.702
|
− 0.283
|
0.554
|
0.583
|
|
Outdoor activities
|
− 0.198
|
− 0.078
|
0.170
|
0.866
|
|
Prior experience
|
0.487
|
0.180
|
0.789
|
0.435
|
|
O'Connor
|
Male
|
− 1.879
|
− 0.059
|
0.297
|
0.768
|
0.038
|
|
Right dominant hand
|
1.090
|
0.031
|
0.164
|
0.870
|
|
Laboratory + after working hours
|
1.201
|
0.036
|
0.179
|
0.859
|
|
Artistic skills
|
− 2.988
|
− 0.202
|
0.895
|
0.377
|
|
Psychomotor skills
|
3.351
|
0.209
|
0.404
|
0.688
|
|
Outdoor activities
|
− 0.262
|
− 0.016
|
0.034
|
0.973
|
|
Prior experience
|
− 2.354
|
− 0.135
|
0.583
|
0.563
|
Note: Multivariate linear regression analysis was used.
a Significant effect at p < 0.05.
In relation to the direct visual test of the left hand, the right dominant hand exhibited
a notable inverse effect compared with the left dominant hand (p = 0.021). Moreover, additional hours spent working in the laboratory showed a substantial
positive effect compared with laboratory training without extra hours (p = 0.046). There was no significant impact observed on the left hand's direct visual
tests in relation to gender, artistic skills, psychomotor skills, outdoor activities,
and prior experience (p > 0.05).
The R2 values of the regression models have been seen to be low, ranging from 0.048
to 0.1, with the greatest value of 0.36 for the left hand. This indicates that the
predictors that were examined are insufficient to accurately predict the dependent
variables related to direct visual perception.
A multivariate linear regression analysis was performed to examine the impact of variables
on the indirect visual test, namely, the difference between pre- and post-measurements.
The predictors, such as gender, dominant hand, extra dental laboratory training, artistic
skills, psychomotor skills, outdoor activities, and prior experience, did not have
a significant impact on the indirect visual test for the right hand, both hands, assembly,
and O'Connor Test (p > 0.05; [Table 10]).
Table 10
Multivariate linear regression analysis to study the effect of predictors on the indirect
visual test (difference between pre- and post-measurements)
|
Predictors
|
Unstandardized coefficients
|
Standardized coefficients
|
t-Value
|
p-Value
|
R
2
|
|
Right hand
|
Male
|
0.126
|
0.021
|
0.105
|
0.917
|
0.029
|
|
Right dominant hand
|
− 0.867
|
− 0.132
|
0.691
|
0.494
|
|
Laboratory + after working hours
|
− 0.495
|
− 0.080
|
0.389
|
0.699
|
|
Artistic skills
|
− 0.221
|
− 0.079
|
0.350
|
0.728
|
|
Psychomotor skills
|
0.435
|
0.144
|
0.278
|
0.783
|
|
Outdoor activities
|
− 0.504
|
− 0.164
|
0.350
|
0.728
|
|
Prior experience
|
0.236
|
0.072
|
0.309
|
0.759
|
|
Left hand
|
Male
|
− 0.907
|
− 0.170
|
0.994
|
0.327
|
0.281
|
|
Right dominant hand
|
− 2.207
|
− 0.501
|
3.798
|
< 0.001[a]
|
|
Laboratory + after working hours
|
1.400
|
0.255
|
1.443
|
0.157
|
|
Artistic skills
|
0.573
|
0.232
|
1.190
|
0.242
|
|
Psychomotor skills
|
0.962
|
0.359
|
0.804
|
0.426
|
|
Outdoor activities
|
− 1.690
|
− 0.621
|
1.538
|
0.133
|
|
Prior experience
|
0.079
|
0.027
|
0.136
|
0.893
|
|
Both hands
|
Male
|
− 0.046
|
− 0.010
|
0.050
|
0.960
|
0.102
|
|
Right dominant hand
|
− 0.076
|
− 0.015
|
0.080
|
0.936
|
|
Laboratory + after working hours
|
− 0.284
|
− 0.058
|
0.295
|
0.770
|
|
Artistic skills
|
0.685
|
− 0.312
|
1.434
|
0.160
|
|
Psychomotor skills
|
− 0.229
|
− 0.096
|
0.193
|
0.848
|
|
Outdoor activities
|
− 0.563
|
− 0.233
|
0.516
|
0.609
|
|
Prior experience
|
− 0.005
|
− 0.002
|
0.009
|
0.993
|
|
Assembly
|
Male
|
− 0.228
|
− 0.070
|
0.369
|
0.714
|
0.113
|
|
Right dominant hand
|
− 0.275
|
− 0.078
|
0.425
|
0.673
|
|
Laboratory + after working hours
|
0.251
|
0.075
|
0.383
|
0.704
|
|
Artistic skills
|
− 0.084
|
− 0.056
|
0.258
|
0.798
|
|
Psychomotor skills
|
− 0.210
|
− 0.129
|
0.260
|
0.796
|
|
Outdoor activities
|
− 0.350
|
− 0.211
|
0.471
|
0.641
|
|
Prior experience
|
0.540
|
0.305
|
1.371
|
0.179
|
|
O'Connor
|
Male
|
− 0.115
|
− 0.005
|
0.026
|
0.979
|
0.100
|
|
Right dominant hand
|
2.861
|
0.114
|
0.620
|
0.539
|
|
Laboratory + after working hours
|
3.306
|
0.140
|
0.706
|
0.484
|
|
Artistic skills
|
− 1.187
|
− 0.111
|
0.511
|
0.613
|
|
Psychomotor skills
|
− 1.978
|
− 0.171
|
0.343
|
0.734
|
|
Outdoor activities
|
− 1.060
|
− 0.090
|
0.200
|
0.843
|
|
Prior experience
|
1.331
|
0.106
|
0.473
|
0.639
|
Note: Multivariate linear regression analysis was used.
a Significant effect at p < 0.05.
Concerning the indirect visual test of the left hand, the right dominant hand exhibited
a notable negative effect in comparison to the left dominant hand (p < 0.001). There was no significant impact observed on the left hand's direct visual
tests (p > 0.05) in relation to gender, further dental laboratory training, artistic skills,
psychomotor skills, outdoor activities, or prior experience. The R2 values of the
regression models have been seen to be weak, ranging from a minimum of 0.029 to a
maximum of 0.113, with the greatest value of 0.28 corresponding to the left hand.
This suggests that the predictors or sample size being examined are inadequate for
predicting the dependent variables of the direct visual test. Further investigation
is needed to identify other predictors.
It is essential to underscore that the results of this study are derived from correlation
and regression analyses, which discern associations but do not confirm causality.
For example, although supplementary training and gender differences were correlated
with enhanced manual dexterity in certain assessments, these findings must not be
construed as causal relationships. To draw such conclusions with certainty, controlled
experimental designs would be necessary.
Discussion
Dental students must possess proficient manual dexterity, especially in preclinical
training laboratories where they learn crucial procedures. For this study, we employed
both the Purdue Pegboard Test and the O'Connor Dexterity Test to assess the improvement
of manual dexterity skills and hand–eye coordination following a dental simulation
preclinical training. Prior studies have shown that these assessments are capable
of forecasting the academic achievement of dental students in preclinical courses.[8]
[9]
Furthermore, research conducted by Neves et al discovered that these assessments can
assess fine motor skills and hand–eye coordination, which are essential for jobs such
as cavity preparations and other manual procedures in dentistry.[10]
This study revealed a significant difference in the total mean scores of the Purdue
and O'Connor dexterity tests when comparing the scores of all participants at T0 and
T1. The results of the study done by Saeed et al were consistent with our findings.
They used the Purdue Pegboard Test and the O'Connor Tweezer Dexterity Test and reported
a significant improvement in students' performance on both tests after receiving preclinical
training with both direct and indirect vision.[5] Unlike the study conducted by Saeed et al, our study found that students who dedicated
additional time to training demonstrated significant improvement in manual dexterity
abilities compared with those who did not allocate extra time. These findings suggest
that practice has a substantial impact on enhancing manual dexterity skills. Similarly,
a study conducted on students enrolled in phantom-head academic courses and administered
assessments at three different time intervals (T0, T1, T2) demonstrated that hand
dexterity may be enhanced and refined through exercise and training. This implies
that by identifying students who have lower manual dexterity skills before preclinical
courses, it is possible to provide specific support to help them achieve the required
levels of dental performance.[2] Therefore, these results substantiate the inference that manual dexterity can be
improved with regular practice and extra training.
The multivariate linear regression analysis did not reveal any statistically significant
gender effect in relation to the direct and indirect visual tests conducted on the
dominant hand, both hands, assembly, and the O'Connor test (p > 0.05). Although previous studies have indicated possible differences in manual
dexterity across genders, current research conducted by Constansia et al has found
that gender does not exert a major influence on manual dexterity. This conclusion
takes into consideration parameters such as finger index and thumb size when comparing
men and women.[11] However, research conducted by Saeed et al found evidence of gender differences
in activities involving manual dexterity.[5]
[12] The only significant difference in manual dexterity between genders in the present
study was in the indirect visual test of the left hand, which aligns with existing
literature. For instance, Psotta et al identified sex-based disparities in fine motor
performance among adolescents,[12] whereas other research observed no such differences in adult cohorts.[11] This inconsistency may indicate developmental, anatomical, or sociocultural factors
affecting motor learning and coordination. Further research is indicated to better
understand the specific impact of gender on manual dexterity in the field of dentistry.
The correlation coefficients between visual test performance and surveyed domains
in this study were found to be near zero, suggesting a weak or nonexistent relationship.
Furthermore, these correlations were not statistically significant (p > 0.05). These data indicate that performance on manual dexterity tests is not significantly
affected by factors such as artistic skills, psychomotor skills, outdoor activities,
or past experience as measured by the survey. Johnson et al discovered a positive
correlation between higher preclinical practical scores and increased engagement in
psychomotor, artistic, and outdoor physical activities. Notwithstanding these findings,
they proposed that engagement in these activities cannot serve as a reliable indicator
for the performance of dental students. This is because they found that not all individuals
with a high level of participation excelled in practical exams, and not all individuals
who excelled in practical exams had high levels of participation in the activity factors.[6]
The study examined the influence of variations in dominant hand preference among persons
who are left-handed or right-handed on the outcomes of dexterity tests, namely, the
Purdue Pegboard Test and O'Connor Tweezer Test. The results indicated that, on the
whole, variations in dominant hand did not have a significant impact on the test outcomes.
However, there was a substantial deviation from the norm in the Purdue DVT test of
the left hand. Left-handed participants displayed considerably higher scores compared
with their right-handed counterparts (p = 0.004). This implies that persons who are left-handed possess proficient manual
dexterity in both their dominant and nondominant hands. Similarly, Judge and Stirling
observed a significant enhancement in the performance of left-handed individuals while
participating in tasks that necessitate coordination between their left and right
hands, as demonstrated by the Purdue Pegboard Test.[13] A supplementary study revealed a correlation between handedness and performance
on the Purdue Pegboard Test, indicating that left-handed individuals occasionally
exhibit superior performance compared with right-handed individuals in specific activities.[14]
However, there is a lack of research examining the impact of left- and right-dominant
hands on manual dexterity outcomes in dentistry, particularly the effects of being
left-handed on manual dexterity and clinical practice. A recent study has uncovered
that dentistry students who are left-handed may face challenges when adapting to dental
tools that are primarily developed for right-handed individuals, as well as when performing
certain dental procedures.[15] Therefore, dental schools should take into consideration the distinct needs of left-handed
students to foster inclusion and improve their performance in clinical practice.
The superior performance of left-handed individuals in the left-hand direct visual
test corresponds with the observations of Judge and Stirling, who identified benefits
for left-handers in tasks necessitating bimanual coordination.[13] Nonetheless, these findings are still limited and need more research in the context
of dental education, especially since left-handed students may have trouble using
mostly right-handed tools and workstations.
Study Limitations
A small sample size from one institution may introduce selection bias and limit generalizability.
Based on self-reported questionnaires, data gathering may have been biased and inaccurate.
Due to the study's short follow-up, socioeconomic status and cognitive abilities were
not sufficiently accounted for, which may have affected the results' validity.
Another notable limitation is the low R
2 values yielded by the regression models, indicating that the included predictors
had limited power in explaining the variance in manual dexterity scores. This suggests
the presence of other influential factors not captured by the survey or study design.
Furthermore, the correlation-based methodology inherently limits the ability to draw
causal conclusions from the observed associations. Lastly, the significant findings
related to gender and handedness should be cautiously interpreted in light of limited
sample diversity and the potential influence of confounding variables not assessed
in this study.
Conclusion
This study provides evidence of the positive impacts of preclinical training on the
manual dexterity skills of dental students. The results show significant increases
in both the Purdue Pegboard Test and the O'Connor Tweezer Dexterity Test after just
one semester. The existence of gender differences in performance indicates the need
for additional research and exploration. To improve the applicability of future research
findings and investigate the long-term consequences, it is recommended to utilize
larger and more diverse participant samples, as well as longitudinal study methods.
It is advisable to use comprehensive tests, in addition to self-reported questionnaires,
to obtain a complete picture of manual dexterity in dentistry education. These observations
can enhance the development of the curriculum and enhance the readiness and confidence
of dentists.
