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Research Concerning Abutment Placement Training using a Navigation System

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Purpose: In teaching practice, it is difficult to give adequate guidance to all students. The purpose of this research is to clarify whether teaching abutment placement using a support system (navigation system) that converts tooth axes to visual information provides guidance equivalent to an instructor.Purpose and methods: Forty 5th-year undergraduate students underwent 2 training sessions total in 60 minutes concerning formation of the axial face of the 1st maxillary molar. For the first training session, an instructor taught 20 students individually (guidance group); the remaining students used the navigation system (navigation group). The second session was without instruction, and students underwent evaluation of the abutment taper angle and buccolingual inclination based on 8 points. Furthermore, presence or absence of misalignment relative to adjacent teeth was assessed visually. Finally, we conducted a survey regarding use of the navigation system.Results: Regarding the mean value of the taper angle, for all comparisons there was no significant difference between the guidance group and the navigation group. Regarding misalignment with adjacent teeth, erroneous formation was recognized in 100% of the guidance group for both mesial and distal and in 70% of the navigation group for both mesial and distal. In the survey, 18 students answered that the navigation system helped them recognize the taper angle.Discussion and conclusion: Based on the results of this study, no significant difference was found in the taper angle between the guidance group and the navigation group. Furthermore, there was reduced misalignment with adjacent teeth in the navigation group. These results suggest that the navigation system could confer the same education effect as instructor guidance.
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Taniguchi et al., Dentistry 2018, 8:10
DOI: 10.4172/2161-1122.1000517
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ISSN: 2161-1122
Dentistry
Open Access
Research Article
Voume 8 • Issue 10 • 1000517
Dentistry, an open access journal
ISSN: 2161-1122
*Corresponding author: Dr Yusuke Taniguchi, Department of Oral
Rehabilitation, Fukuoka Dental College, Fukuoka, Japan, Tel: 81928010411;
E-mail: yuusuke@college.fdcnet.ac.jp
Received November 01, 2018; Accepted November 14, 2018; Published
November 16, 2018
Citation: Taniguchi Y, Tsuzuki T, Kakura K, Yoneda M, Isshi K, et al. (2018)
Research Concerning Abutment Placement Training using a Navigation System.
Dentistry 8: 517. doi:10.4172/2161-1122.1000517
Copyright: © 2018 Taniguchi Y, et al. This is an open-access article distributed
under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the
original author and source are credited.
Research Concerning Abutment Placement Training using a Navigation
System
Yusuke Taniguchi1*, Takashi Tsuzuki2, Kae Kakura3, Masahiro Yoneda4, Kota Isshi5, Takashi Tsutsumi2, Tomohiro Kawaguchi2, Chihiro
Koga6 and Hirofumi Kido3
1Section of Crown and Bridge, Department of Oral Rehabilitation, Fukuoka Dental College, Japan
2Section of Removable Prosthodontics, Department of Oral Rehabilitation, Fukuoka Dental College, Japan
3Section of Oral Implantology, Department of Oral Rehabilitation, Fukuoka Dental College, Japan
4Section of General Dentistry, Department of General Dentistry, Fukuoka Dental College, Japan
5Central Dental Laboratory, Fukuoka Dental College Medical and Dental General Hospital, Japan
6Centre for Oral diseases, Fukuoka Dental College Medical and Dental General Hospital, Japan
system) that converts tooth axes to visual information provides
guidance equivalent to an instructor.
Materials and Methods
Navigation system
e navigation system (Inliant, Navigate Surgical Technologies;
Navident, ClaroNav) is a support system that converts the tooth axes
into visual information. For the present research, we applied the
navigation system so that the axes of the abutment tooth were clearly
visible during formation, making it possible to visually understand the
tooth axes when the students were forming abutment teeth (Figure 1).
Scan templates were attached to the models used in our experiment
(Invictus Dental Education Model, Nissin Dental Products Inc. Kyoto,
Japan), CT images were obtained by scanning the model, data were
combined by synchronizing the scan template attached to the turbine
with an extraoral scanner, and the position of the turbine was displayed
Keywords: Training for preparation of abutment teeth; Navigation
system; Taper angle; Misalignment of adjacent teeth
Introduction
In the practice of teaching students, because methods for evaluation
of the teaching of abutment tooth formation have been le up to the
discretion of each instructor, objectivity has been poor, and there
have been dierences in training contents from student to student.
In order to solve these problems, we have spent time establishing
objective methods for evaluation through techniques such as instructor
calibration and practical examination. Nevertheless, these problems
have persisted, and there are still students who cannot successfully form
an abutment surface. In the conventional style of practical instruction,
the skill level of the instructor greatly inuences teaching and evaluation
[1,2]. Moreover, in order to allow students to correctly recognize tooth
axes which are important for forming abutment teeth, it is necessary
that there be separate instruction, which is a problem that increases
the burden on the individual instructor. Additionally, when there are
only a few instructors for students, it can be dicult for students to
receive the appropriate instruction in the time allotted, which can make
it a challenge even for students to recognize problems in abutment
formation. It is expected that the application of digital technology to
student education will improve these problems [3-6]. In recent years, a
system for surgical support has been developed that converts the axes of
the implant tooth into visual information [7]. Application of the system
to abutment teeth implantation education is expected to be an eective
method for improving the aforementioned problems.
erefore, for the present study, we sought to clarify whether
teaching abutment placement using a support system (navigation
Abstract
Purpose: In teaching practice, it is difcult to give adequate guidance to all students. The purpose of this research
is to clarify whether teaching abutment placement using a support system (navigation system) that converts tooth axes
to visual information provides guidance equivalent to an instructor.
Purpose and methods: Forty 5th-year undergraduate students underwent 2 training sessions total in 60 minutes
concerning formation of the axial face of the 1st maxillary molar. For the rst training session, an instructor taught
20 students individually (guidance group); the remaining students used the navigation system (navigation group).
The second session was without instruction, and students underwent evaluation of the abutment taper angle and
buccolingual inclination based on 8 points. Furthermore, presence or absence of misalignment relative to adjacent teeth
was assessed visually. Finally, we conducted a survey regarding use of the navigation system.
Results: Regarding the mean value of the taper angle, for all comparisons there was no signicant difference
between the guidance group and the navigation group. Regarding misalignment with adjacent teeth, erroneous
formation was recognized in 100% of the guidance group for both mesial and distal and in 70% of the navigation group
for both mesial and distal. In the survey, 18 students answered that the navigation system helped them recognize the
taper angle.
Discussion and conclusion: Based on the results of this study, no signicant difference was found in the taper angle
between the guidance group and the navigation group. Furthermore, there was reduced misalignment with adjacent
teeth in the navigation group. These results suggest that the navigation system could confer the same education effect
as instructor guidance.
Page 2 of 4
Citation: Taniguchi Y, Tsuzuki T, Kakura K, Yoneda M, Isshi K, et al. (2018) Research Concerning Abutment Placement Training using a Navigation System.
Dentistry 8: 517. doi:10.4172/2161-1122.1000517
Voume 8 • Issue 10 • 1000517
Dentistry, an open access journal
ISSN: 2161-1122
on the CT image on a monitor. erefore, when abutment teeth are
formed, the tooth axes are visually represented by the dynamic tracking
of the turbine and the monitoring of positional relationships.
Practicum methods
We targeted 40, 5th-year students who had successfully passed their
objective structured clinical examination (OSCE) and who were able
to safely use the air turbine for the formation of the right 1st maxillary
molar for 30-minute sessions total in 60 minutes. An instructor who is
a Prosthodontics specialist taught 20 students individually (guidance
group) for the rst session, before these students were instructed to
form abutment teeth in a practical exam; the remaining 20 students
used the navigation system (navigation group) for the rst session, then
underwent a practical examination for the second session (Figure 2).
e abutment teeth formed in the practical examination were
collected and evaluation of each abutment tooth was performed using
the dental CAD/CAM system CEREC. e taper angle along with
mesio-distal and buccal-lingual alignments was determined based on
4 corners using 8 points-clockwise from the lingual aspect A, B, C,
D, A', B', C', D' (Figure 3). Concerning our measurement methods,
the collected abutment tooth was converted into data using a digital
scanner. e taper angle is determined from the divided plane relative
to the tooth axis. Measurement is performed from 0.5 mm above the
nish line to the center of the crown. e taper angle was calculated as
the average value (Figure 4). Furthermore, the presence or absence of
misalignment relative to adjacent teeth was assessed visually.
Aer the practical examination, we conducted a survey regarding
the use of the navigation system. Survey contents were as follows: "Was
the navigation system easy to use?", "Did the navigation system help in
forming the abutment?", and "Was the navigation system helpful for
understanding the tooth axes for forming the abutment?
Statistics
All values are expressed as mean +/- standard deviation (n, number
Scan template
Monitor
Tooth axis
Bar axis
Scaner
Figure 1: Using the navigation system.
Undergraduate 5
th
grade 40students
Navigation
system group;
20 students
Instructor
group;
20 students
Tooth preparation Practice test (#16)
Taper angles measurement
(mesial, distal, buccul, lingul, 4corners)
Statistical analysis
Figure 2: Research protocol owchart.
Buccul B,
C,
D,
A,
A
B
C
D
Mes i a l
L in gul
D i s ta l
Figure 3: Measurement of the taper angle in an abutment tooth.
Figure 4: Measurement of the taper angle in an abutment tooth.
a. Finish line
b. 0.5 mm above the nish line
c. Taper angle
d. Crown center
Page 3 of 4
Citation: Taniguchi Y, Tsuzuki T, Kakura K, Yoneda M, Isshi K, et al. (2018) Research Concerning Abutment Placement Training using a Navigation System.
Dentistry 8: 517. doi:10.4172/2161-1122.1000517
Voume 8 • Issue 10 • 1000517
Dentistry, an open access journal
ISSN: 2161-1122
of subjects). Statistical analyses were performed using SPSS version 19
(SPSS Inc., Chicago, Illinois) using Student's t-test or one-way analysis
of variance (ANOVA) with repeated measures followed by Bonferroni's
post hoc test. A signicant dierence was assumed when the p-value
was less than 0.05.
Results
Angles in the guidance group were as follows: A, 13.0°; B, 8.5°; C,
7.5°; D, 6.5°; A, 4.9°; B’, 11.5°; C’, 12.8°; D’, 13.3°. Angles in the navigation
group were: A, 13.2°; B, 7.0°; C, 8.2°; D, 5.9°; A’, 6.1°; B’, 10.6°; C’, 14.1°;
D’, 12.7°. ere was no dierence between the guidance group and the
navigation group at any measurement point. Furthermore, there was no
signicant dierence between the taper angles of the guidance group
and the navigation group at 10.0 ± 2.7° and 9.6 ± 3.2° respectively
(Figure 5).
With respect to the presence or absence of misalignment of adjacent
teeth, there was 100% mismatch observed for both mesial and distal
aspects in the guidance group. In the navigation group, there was 70%
misalignment observed in both mesial and distal aspects (Figure 6).
In the survey administered to the navigation group, six students
answered that the navigation system was easy to use, whereas 10
students responded that it was cumbersome and dicult to use. ere
were 18 students who said that the navigation system helped them to
recognize the taper angle of the abutment tooth; 16 students answered
that the navigation system was eective at helping them gain a visual
familiarity with the tooth axes.
Discussion
In education for abutment tooth formation, few instructors
are oen responsible for many students. ey must teach students
individually while also keeping track of progress for the whole group.
In such an educational environment, instruction becomes focused on
students who are slow in practical training and on students who ask
questions. Questions have been raised that such an environment might
not provide a stable teaching situation [8]. In particular, it is oen
dicult to instruct several students at the same time, as students benet
from individual guidance during the formation of abutment teeth. For
this reason, it is common practice for students to engage in abutment
tooth formation on their own and to ask the instructor to judge their
performance aer the fact. It has been reported that the taper angle of
the abutment teeth formed by many students increased as the students
have more freedom from individualized instruction in their design [9].
As a method for improving these problems, various systems of
educational support for abutment tooth formation have been reported
[10,11]. Nevertheless, these educational systems have not been applied to
actual clinical practice. In the present study, a surgical support navigation
system for converting tooth axes into visual information which has already
been clinically applied to oral surgery was further applied to abutment
tooth formation education. Since the tooth axes are displayed in real time,
by using this system for the formation of abutment teeth, students can
clearly recognize positions and angles at sites which are dicult to see, and
it is possible to visually recognize the taper of the formed tooth angle. By
using this navigation, students can self-learn abutment tooth formation
without relying on instructors [12,13].
In this study, there was no signicant dierence between the taper
angle of abutment teeth of students instructed by an instructor and taper
angle of abutment teeth self-learned by students using the navigation
system. Based on this, it is suggested that the navigation system enables
students to visually recognize the tooth axis of the abutment tooth
without requiring individual attention from an instructor. Information
of an abutment tooth, it is dicult to perceive the axial aspect of the bar
at sites where visibility is dicult. Furthermore, if slicing is performed,
there is the possibility of mistakenly drilling adjacent teeth unless the
axial face is visualized [14].
In this study, the proportion of errors in alignment with adjacent
teeth in the guidance group was 100% for both mesial and distal
teeth. When students self-learned using the navigation system to
form abutment teeth, the ratio of misalignment with adjacent teeth
was 70% for both mesial and distal teeth. By applying the navigation
system, students were able to visualize the tooth axes even at sites where
visibility was challenging. is suggests the proportion of misaligned
teeth is less with the use of navigation. ere are many advantages to
the navigation system, including that it does not need quite as large an
opening compared to a guide stent, it is possible to drill the implant
while grasping the bone surface, and easy injection of water, since
the device used outside the mouth is large and the navigation system
displays the implant axes in real time. If there is an error in the system,
operations using the navigation system cannot be continued.
As part of this research, we interviewed students in the navigation
group. ere were many problems identied, such as the navigation
system equipment being heavy and dicult to use, and the learning
curve required to get used to the navigation system. Nevertheless, most
students had a positive reaction and believed they were conscious of the
taper angle when forming abutment teeth.
More than this, there are some problems when applying the
navigation system to abutment tooth formation education, but it
seems to be an eective educational adjunct for the future. Since it is
necessary to clarify the problems of this system, we believe that further
examination is required to determine the best ways to apply navigation
to student education.
(a) (b)
Instructor group
Naviagtion group
Instructor
group
Naviagtion
group
Taper angle
Taper angle
40
30
20
10
0
(a)
A B C D ABCD’’
(b)
15
10
5
0
Figure 5: (a) Taper angle by site, (b) Taper angle by study arm.
Instructor
group
Mesial
100% 70%
70%100%
Distal
Navigation
group
Figure 6: Proportion of misalignment in each group.
Page 4 of 4
Citation: Taniguchi Y, Tsuzuki T, Kakura K, Yoneda M, Isshi K, et al. (2018) Research Concerning Abutment Placement Training using a Navigation System.
Dentistry 8: 517. doi:10.4172/2161-1122.1000517
Voume 8 • Issue 10 • 1000517
Dentistry, an open access journal
ISSN: 2161-1122
Conclusion
In our model of training, it is suggested that the navigation system
delivers the same educational eect as instructor-based guidance.
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ResearchGate has not been able to resolve any citations for this publication.
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A questionnaire investigation of criteria for evaluating abutment form preparation by instructor of dental students training
  • K Iwanami
  • T Ogawa
  • Y Shigeta
  • E Ando
  • S Fukushima
Iwanami K, Ogawa T, Shigeta Y, Ando E, Fukushima S (2006) A questionnaire investigation of criteria for evaluating abutment form preparation by instructor of dental students training. Journal of Japanese Association for Dental Education 22: 150-154.