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Digital Evaluation of the Accuracy of Computer-Guided Dental Implant Placement: An In Vitro Study

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Compared to traditional implant surgical guides, computer-assisted implant surgical guides can be considered for positioning implants in the final prosthesis. These computer-assisted implant surgical guides can be easily fabricated with personal 3D printers after being designed with implant planning CAD software. Although the accuracy of computer-assisted implant surgical guides fabricated using personal 3D printers is an important factor in their clinical use, there is still a lack of research examining their accuracy. Therefore, this study evaluated the accuracy of computer-assisted implant surgical guides, which were designed using two implant planning CAD software programs (Deltanine and R2gate software) and fabricated with personal 3D printers using a non-radiographic method. Amongst the patients who visited Kyungpook National University Dental Hospital, one patient scheduled to undergo surgery of the left mandibular second premolar was randomly selected. Twenty partially edentulous resin study models were produced using a 3D printer. Using the Deltanine and R2gate implant planning CAD software, 10 implant surgical guides per software were designed and produced using a personal 3D printer. The implants (SIII SA (Ø 4.0, L = 10 mm), Osstem, Busan, Korea) were placed by one skilled investigator using the computer-assisted implant surgical guides. To confirm the position of the actual implant fixture, the study models with the implant fixtures were scanned with a connected scan body to extract the STL files, and then overlapped with the scanned file by connecting the scan body-implant fixture complex. As a result, the mean apical deviation of the Deltanine and R2gate software was 0.603 ± 0.19 mm and 0.609 ± 0.18 mm, while the mean angular deviation was 1.97 ± 0.84 • and 1.92 ± 0.52 • , respectively. There was no significant difference between the two software programs (p > 0.05). Thus, the accuracy of the personal 3D printing implant surgical guides is in the average range allowed by the dental clinician.
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applied
sciences
Article
Digital Evaluation of the Accuracy of
Computer-Guided Dental Implant Placement:
An In Vitro Study
Seong-Min Kim 1,2, Keunbada Son 2,3 , Duk-Yeon Kim 2and Kyu-Bok Lee 1,2,*
1
Department of Prosthodontics, School of Dentistry, Kyungpook National University, 2177 Dalgubeol-daero,
Jung-gu, Daegu 41940, Korea
2Advanced Dental Device Development Institute, Kyungpook National University, 2177 Dalgubeol-daero,
Jung-gu, Daegu 41940, Korea
3Department of Dental Science, Graduate School, Kyungpook National University, 2177 Dalgubeol-daero,
Jung-gu, Daegu 41940, Korea
*Correspondence: kblee@knu.ac.kr; Tel.: +82-053-600-7674
Received: 19 July 2019; Accepted: 13 August 2019; Published: 16 August 2019


Abstract:
Compared to traditional implant surgical guides, computer-assisted implant surgical
guides can be considered for positioning implants in the final prosthesis. These computer-assisted
implant surgical guides can be easily fabricated with personal 3D printers after being designed
with implant planning CAD software. Although the accuracy of computer-assisted implant surgical
guides fabricated using personal 3D printers is an important factor in their clinical use, there is
still a lack of research examining their accuracy. Therefore, this study evaluated the accuracy of
computer-assisted implant surgical guides, which were designed using two implant planning CAD
software programs (Deltanine and R2gate software) and fabricated with personal 3D printers using
a non-radiographic method. Amongst the patients who visited Kyungpook National University
Dental Hospital, one patient scheduled to undergo surgery of the left mandibular second premolar
was randomly selected. Twenty partially edentulous resin study models were produced using a
3D printer. Using the Deltanine and R2gate implant planning CAD software, 10 implant surgical
guides per software were designed and produced using a personal 3D printer. The implants (SIII
SA (Ø 4.0,
L=10 mm
), Osstem, Busan, Korea) were placed by one skilled investigator using the
computer-assisted implant surgical guides. To confirm the position of the actual implant fixture,
the study models with the implant fixtures were scanned with a connected scan body to extract the
STL files, and then overlapped with the scanned file by connecting the scan body-implant fixture
complex. As a result, the mean apical deviation of the Deltanine and R2gate software was 0.603
±
0.19 mm and 0.609
±
0.18 mm, while the mean angular deviation was 1.97
±
0.84
and 1.92
±
0.52
,
respectively. There was no significant dierence between the two software programs (p>0.05). Thus,
the accuracy of the personal 3D printing implant surgical guides is in the average range allowed by
the dental clinician.
Keywords:
dental implant; computer-aided design; implant surgical guide; additive manufacturing
1. Introduction
Digital dentistry has evolved from cone-beam computed tomography (CBCT), intra-oral scanners,
computer-aided design (CAD) software, and computer-aided manufacturing (CAM), which has had a
profound impact on dental implantology [
1
3
]. In particular, additive manufacturing (AM) technology,
known as 3D printing, has contributed to the successful implementation of computer-guided implant
surgery [
1
,
3
]. Traditional implant surgical guides with modified radiographic templates require
Appl. Sci. 2019,9, 3373; doi:10.3390/app9163373 www.mdpi.com/journal/applsci
Appl. Sci. 2019,9, 3373 2 of 8
complex laboratory procedures which can be inaccurate, making it somewhat dicult to accurately
position implants in their planned locations [
4
9
]. On the other hand, computer-assisted implant
surgical guides can consider important anatomical structures, save time, and aid implant placement by
drawing the pre-planned final prosthesis design [1012].
Accurate computer-assisted implant surgical guides are designed with implant planning CAD
software to process the information obtained from CBCT, intra-oral scanners, and diagnostic casts [
13
].
Several studies have previously measured the accuracy of computer-assisted implant surgical guides
designed using various implant planning CAD software [
14
]. According to a systemic review of the
accuracy of the implant surgical guides, the mean apical deviation between the planned position and
placed position was 1.4 mm, and the angle deviation was 3.5
[
15
]. However, the deviations may vary
in dierent studies [16].
Son’s study shows that the positioning accuracy of computer-guided implants can vary depending
on experimental conditions, and that the accuracy of a cone beam computed tomogram (CBCT) or
intraoral scanning of the patient, and the accuracy of 3D printing or milling, have been reported to have
a significant eect on the positioning of implants [
17
]. If the positioning accuracy of computer-guided
implants is inaccurate, it can lead to an unintended position, which may be the biggest cause of
implant failure.
The positioning accuracy of the placed implants is measured by superimposing the pre- and
post-operative CBCT images. However, CBCT can be inaccurate due to resolution and distortion, and
errors may occur during the superposition of the CBCT images. In addition, the presence of metal
artifacts in the oral cavity may lower the resolution of the CBCT images [
18
,
19
]. A non-radiographic
method has been recently introduced to obtain the implant position and measure the placed implant
position, by using an intraoral scanner and superimposing it on the previously obtained implant fixture
scan data [
20
]. This allows for evaluation of the accuracy of the placed implant without post-operative
CBCT imaging.
In the 1980s, Charles Hull developed an early 3D printing device called the stereolithography
apparatus (SLA) that could create 3D models from digital data [
21
]. Since the important patents of AM
technology have recently expired, the 3D-printer market is further developing [
22
]. As a result, smaller
3D printers are being introduced into dental clinics quicker and with lower costs [
23
,
24
]. These 3D
printers are called in-oce or personal 3D printers [
25
,
26
]. Computer-assisted implant surgical guides
can be easily produced with personal 3D printers after being designed with implant planning CAD
software [27].
Although the accuracy of computer-assisted implant surgical guides produced by personal 3D
printers is an important factor in their clinical use, there is still a lack of research examining their
accuracy. Therefore, this study evaluated the accuracy of computer-assisted implant surgical guides,
which were designed using implant planning CAD software (Deltanine and R2gate software) and
fabricated with personal 3D printers using a non-radiographic method. The null hypothesis of this
study is that there is no dierence in the accuracy of surgical guides fabricated by both types of software.
2. Materials and Methods
Amongst the patients who visited Kyungpook National University Dental Hospital, one patient
who was scheduled to undergo surgery of the left mandibular second premolar with an identifiable
inferior alveolar nerve was randomly selected. Before placing the implant, we took a preliminary
impression and created a diagnostic cast using hard plaster. A 3D model scanner (Freedom HD, Degree
of Freedom, Seoul, Korea) was used to scan the diagnostic model and save the patient’s intraoral
soft tissue surface information in a Surface Tesselation Language (STL) file. The patient’s hard-tissue
information was obtained using CBCT (Alphard-3030, ASAHI Rogentgen, Kyoto, Japan) and stored as
a Digital Imaging and Communication in Medicine (DICOM) file. Twenty partially edentulous resin
study models were produced using a 3D printer (ZENITH, Dentis, Daegu, Korea). To replicate the
cancellous bone on the mandibular second premolar alveolar bone, the resin on the opposite side of
Appl. Sci. 2019,9, 3373 3 of 8
the study models was removed from the surface of the alveolar bone, and the removed portion was
hardened by filling it with orthodontic resin (Dentsply Sirona, York, PA, USA) and sawdust. Twenty
partially edentulous resin study models were scanned (CS3600, Carestream Dental LLC, Atlanta, GA,
USA) and the results were saved as standard tessellation language (STL) files.
Pilot experiments were conducted 2 times to determine the sample size, and 8 samples per
software were calculated using a power analysis software (G*Power v3.1.9.2, Heinrich Heine University,
Düsseldorf, Germany) (actual power =95.05%; power =95%;
α
=0.05). To increase power, the number
of samples presented in this study was determined to be 10 per software.
Using the Deltanine (Daesung, Seoul, Republic of Korea) and R2gate (Megagen, Daegu, Republic
of Korea) implant planning CAD software; the CBCT DICOM file taken before placement, and the
intraoral scanning STL file were retrieved and overlapped (Figure 1A), the implant position was
planned (Figure 1B), and a computer-assisted implant surgical guide was produced (Figure 1C). Ten
implant surgical guides per software were designed and fabricated using a personal 3D printer (n=10)
(Figure 1D).
Appl. Sci. 2019, 9, x FOR PEER REVIEW 3 of 8
Dental LLC, Atlanta, GA, USA) and the results were saved as standard tessellation language (STL)
files.
Pilot experiments were conducted 2 times to determine the sample size, and 8 samples per
software were calculated using a power analysis software (G*Power v3.1.9.2, Heinrich Heine
University, Düsseldorf, Germany) (actual power = 95.05%; power = 95%; α = 0.05). To increase power,
the number of samples presented in this study was determined to be 10 per software.
Using the Deltanine (Daesung, Seoul, Republic of Korea) and R2gate (Megagen, Daegu, Republic
of Korea) implant planning CAD software; the CBCT DICOM file taken before placement, and the
intraoral scanning STL file were retrieved and overlapped (Figure 1A), the implant position was
planned (Figure 1B), and a computer-assisted implant surgical guide was produced (Figure 1C). Ten
implant surgical guides per software were designed and fabricated using a personal 3D printer (n =
10) (Figure 1D).
Figure 1. Process of surgical guide production. (A) Overlap between data. (B) Implant position plan.
(C) Virtual surgical guide production. (D) Surgical guide production through a 3D printer.
The implants (TSIII SA (Ø 4.0, L = 10 mm), Osstem, Busan, Korea) were placed by one skilled
investigator using the computer-assisted implant surgical guides and one guide surgical kit (Osstem,
Busan, Korea). All implant fixture placement procedures were conducted by one skilled investigator.
The accuracy of the implant fixture placement angle was evaluated by measuring the angle of
the straight line connecting the top and bottom of each implant fixture (Figure 2A). Accuracy of the
implant fixture placement depth was confirmed by measuring the length of the straight line
connecting the planned implant fixture apex and the placed implant fixture apex (Figure 2B).
Figure 1.
Process of surgical guide production. (
A
) Overlap between data. (
B
) Implant position plan.
(C) Virtual surgical guide production. (D) Surgical guide production through a 3D printer.
The implants (TSIII SA (Ø 4.0, L =10 mm), Osstem, Busan, Korea) were placed by one skilled
investigator using the computer-assisted implant surgical guides and one guide surgical kit (Osstem,
Busan, Korea). All implant fixture placement procedures were conducted by one skilled investigator.
The accuracy of the implant fixture placement angle was evaluated by measuring the angle of
the straight line connecting the top and bottom of each implant fixture (Figure 2A). Accuracy of the
implant fixture placement depth was confirmed by measuring the length of the straight line connecting
the planned implant fixture apex and the placed implant fixture apex (Figure 2B).
Appl. Sci. 2019,9, 3373 4 of 8
Appl. Sci. 2019, 9, x FOR PEER REVIEW 3 of 8
Dental LLC, Atlanta, GA, USA) and the results were saved as standard tessellation language (STL)
files.
Pilot experiments were conducted 2 times to determine the sample size, and 8 samples per
software were calculated using a power analysis software (G*Power v3.1.9.2, Heinrich Heine
University, Düsseldorf, Germany) (actual power = 95.05%; power = 95%; α = 0.05). To increase power,
the number of samples presented in this study was determined to be 10 per software.
Using the Deltanine (Daesung, Seoul, Republic of Korea) and R2gate (Megagen, Daegu, Republic
of Korea) implant planning CAD software; the CBCT DICOM file taken before placement, and the
intraoral scanning STL file were retrieved and overlapped (Figure 1A), the implant position was
planned (Figure 1B), and a computer-assisted implant surgical guide was produced (Figure 1C). Ten
implant surgical guides per software were designed and fabricated using a personal 3D printer (n =
10) (Figure 1D).
Figure 1. Process of surgical guide production. (A) Overlap between data. (B) Implant position plan.
(C) Virtual surgical guide production. (D) Surgical guide production through a 3D printer.
The implants (TSIII SA (Ø 4.0, L = 10 mm), Osstem, Busan, Korea) were placed by one skilled
investigator using the computer-assisted implant surgical guides and one guide surgical kit (Osstem,
Busan, Korea). All implant fixture placement procedures were conducted by one skilled investigator.
The accuracy of the implant fixture placement angle was evaluated by measuring the angle of
the straight line connecting the top and bottom of each implant fixture (Figure 2A). Accuracy of the
implant fixture placement depth was confirmed by measuring the length of the straight line
connecting the planned implant fixture apex and the placed implant fixture apex (Figure 2B).
Figure 2.
Measuring deviations between planned (red) and placed (gray) implants. (
A
) Angular
deviation at the central axis of the implant. (B) Linear deviation at implant apex.
To evaluate the apical deviation and angular deviation, 3D inspection software (Geomagic control
X, 3D system, Morrisville, NY, USA) was used, and the scan, design, and sleeve indicator STL files
were extracted from the implant planning CAD software and overlapped to show the position of the
planned implant fixture (Figure 3A). To confirm the position of the actual implant fixture, the study
models with implant fixtures were scanned with a connected scan body (Osstem, Busan, Korea) to
extract STL files, and were overlapped with the scanned file by connecting the scan body-implant
fixture complex (Figure 3B). Precise scan data was obtained by calibration of the 3D scanner, and the
operator performed the evaluation by confirming the exact overlapping in the 3D inspection software.
A virtual cylinder was created for each implant fixture placed after planning with a 3D inspection
software, and the angular deviation was assessed by evaluating the angle dierence. Virtual points
were created on the sleeve indicator and the tip of the placed implant fixture, and the apical deviation
was assessed by measuring the distance between the two points (Figure 3D).
Appl. Sci. 2019, 9, x FOR PEER REVIEW 4 of 8
Figure 2. Measuring deviations between planned (red) and placed (gray) implants. (A) Angular
deviation at the central axis of the implant. (B) Linear deviation at implant apex.
To evaluate the apical deviation and angular deviation, 3D inspection software (Geomagic
control X, 3D system, Morrisville, NY, USA) was used, and the scan, design, and sleeve indicator STL
files were extracted from the implant planning CAD software and overlapped to show the position
of the planned implant fixture (Figure 3A). To confirm the position of the actual implant fixture, the
study models with implant fixtures were scanned with a connected scan body (Osstem, Busan, Korea)
to extract STL files, and were overlapped with the scanned file by connecting the scan body-implant
fixture complex (Figure 3B). Precise scan data was obtained by calibration of the 3D scanner, and the
operator performed the evaluation by confirming the exact overlapping in the 3D inspection
software. A virtual cylinder was created for each implant fixture placed after planning with a 3D
inspection software, and the angular deviation was assessed by evaluating the angle difference.
Virtual points were created on the sleeve indicator and the tip of the placed implant fixture, and the
apical deviation was assessed by measuring the distance between the two points (Figure 3D).
All data were analyzed using the Statistical Package for the Social Sciences (version 25.0, IBM,
Chicago, IL, USA) (α = 0.05). First, the normal distribution of data was investigated using a Shapiro–
Wilk test. Equality of variance was evaluated using the Levene test for normal distribution. To
compare the accuracy of the surgical guide fabricated according to software, the difference was
analyzed using an independent t-test.
Figure 3. Digital evaluation method through 3D inspection software. (A) Planned implant position
through an overlap between the data extracted from computer-guided implant software. (B) Placed
implant position through scan body overlap. (C) Overlap between the data of the planned implants
and the placed implants. (D) Deviation measurement through a virtual cylinder.
3. Results
For the 20 study models in which implant fixtures were placed, the depth and angle of the
planned implant fixture and the placed implant fixture were compared and, as a result, the mean
apical deviation of Deltanine and R2gate software was 0.603 ± 0.19 mm and 0.609 ± 0.18 mm, while
the mean angular deviation of Deltanine and R2gate software was 1.97 ± 0.84° and 1.92 ± 0.52°,
respectively (Tables 1 and 2). There was no significant difference between the mean apical deviation
of the two software programs (p = 0.948), and there was no significant difference between the mean
angular deviation of the two software programs (p = 0.884).
Figure 3.
Digital evaluation method through 3D inspection software. (
A
) Planned implant position
through an overlap between the data extracted from computer-guided implant software. (
B
) Placed
implant position through scan body overlap. (
C
) Overlap between the data of the planned implants
and the placed implants. (D) Deviation measurement through a virtual cylinder.
Appl. Sci. 2019,9, 3373 5 of 8
All data were analyzed using the Statistical Package for the Social Sciences (version 25.0, IBM,
Chicago, IL, USA) (
α
=0.05). First, the normal distribution of data was investigated using a Shapiro–Wilk
test. Equality of variance was evaluated using the Levene test for normal distribution. To compare the
accuracy of the surgical guide fabricated according to software, the dierence was analyzed using an
independent t-test.
3. Results
For the 20 study models in which implant fixtures were placed, the depth and angle of the
planned implant fixture and the placed implant fixture were compared and, as a result, the mean apical
deviation of Deltanine and R2gate software was 0.603
±
0.19 mm and 0.609
±
0.18 mm, while the mean
angular deviation of Deltanine and R2gate software was 1.97
±
0.84
and 1.92
±
0.52
, respectively
(Tables 1and 2). There was no significant dierence between the mean apical deviation of the two
software programs (p=0.948), and there was no significant dierence between the mean angular
deviation of the two software programs (p=0.884).
Table 1.
Apical and angular deviations between the planned implant fixture and the placed implant
fixture of the surgical guides fabricated with the Deltanine software.
No. Apical Deviation (mm) Angular Deviation ()
10.4264 1.378
20.9347 2.8391
30.8911 2.3762
40.4799 3.213
50.6554 1.102
60.6141 3.0092
70.3532 1.4332
80.6747 2.1232
90.4748 1.2342
10 0.5325 0.9968
Mean 0.60368 1.9704
Standard Deviation 0.19182 0.8465
Table 2.
Apical and angular deviations between the planned implant fixture and the placed implant
fixture of the surgical guides fabricated with the R2gate software.
No. Apical Deviation (mm) Angular Deviation ()
10.6219 1.9113
20.4728 1.3134
30.9832 2.983
40.7261 2.0142
50.6281 1.8602
60.3729 1.4312
70.5812 1.9786
80.4981 1.6823
90.3827 1.4821
10 0.8273 2.5829
Mean 0.6094 1.9239
Standard Deviation 0.1845 0.5207
4. Discussion
The location of the planned implants and placed implants have traditionally been evaluated by
comparing the pre- and post-operative CBCT images. In addition, the image artifacts and patient
movements can aect the quality of the CBCT images and limit their accuracy. This study evaluated
the accuracy of computer-assisted implant surgical guides made with personal 3D printers using a
Appl. Sci. 2019,9, 3373 6 of 8
non-radiographic method that overlapped the scan image of the study model with the scan body and
the scan body-implant fixture complex, respectively. In 2019, Tang et al. compared the traditional
radiographic method of evaluating the implant position using CBCT, with the non-radiographic
method of overlapping the scan data and inferring the implant position, and reported that there were
no statistically significant dierences between these methods [
20
]. Therefore, the evaluation of the
implant position in this study is acceptable.
The positioning accuracy of the implant surgical guides can be determined by evaluating the
deviation between the planned implant position and placed implant position [
28
]. These deviations
represent dierent values in various papers [
14
]. However, a 1
deviation of the insertion angle makes
an apical deviation of 0.34 mm based on a 10 mm implant fixture. In other words, a 5
deviation of
the insertion angle represents an apical deviation of 1.7 mm. If the space between the implant and
the adjacent tooth root is 1.5 mm, an angular deviation of 5
implies that it can invade the adjacent
tooth root [
29
]. When considering important anatomical structures such as the inferior alveolar
nerve, implant surgical guides have an allowable vertical and angle deviation of up to 1.5 mm and
3
, respectively [
30
]. Therefore, the vertical deviation and angle deviation in this study are within
clinical tolerance.
As a result of placing implant fixtures in each of the 20 study models, there was no surgical guide
fabricated with the two software programs outside the vertical deviation of 1.5 mm, and there was no
statistically significant dierence between the two software programs (p=0.948). One surgical guide
fabricated with the Deltanine software was out of tolerance of the 3
angle deviation, but there was
no statistically significant dierence between the two software programs (p=0.884). In light of these
results, it can be concluded that the surgical guide fabricated according to the software showed no
dierence in the positioning accuracy of the implants. The Deltanine software used in this study was
compared to the R2gate software, which has been verified in the accuracy of implant placement in
a previous study [
17
]. Although not compared to traditional implant surgical guides, the Deltanine
software has been verified in comparison to the R2gate software and verified in a previous study.
The 20 resin study models used in this study had a rigid cortical bone. The inside surface was
removed and filled with a mixture of orthodontic resin and sawdust, which had a lower physical
property, thereby forming the cancellous bone. Since the thickness of the cortical bone varies in the
clinical setting, this study also arbitrarily set the thickness of the cortical bone. In the case of a rigid
personal 3D printer resin, the drill and fixture got stuck in the hard resin during the drilling process
resulting in an error. In addition, fabrication of the implant surgical guides with personal 3D printers
was thought to cause internal errors due to the removal of undercuts and nodules and the proficiency
of the surgeon who placed the implants. Given that this was an in-vitro study measuring the accuracy
of implant surgical guides made with personal 3D printers, errors above the mean can be fatal in the
clinical setting. However, since the cortical bone has lower strength and higher elasticity compared to
hard resin, errors due to the drill would be smaller when the implant is placed. Although the study
model was fabricated in consideration of the actual clinical environment, further studies are needed to
apply it to patients in actual clinical trials.
5. Conclusions
Based on the findings of this in-vitro study, the following conclusions were drawn:
1.
The surgical guide fabricated according to the two software programs shows no dierence in the
positioning accuracy of the implants.
2.
The accuracy of the personal 3D printed implant surgical guides is in the average range allowed
by the dental clinician.
3.
The surgical guide fabricated by the method presented in this study can be utilized in dental
clinical practice.
Appl. Sci. 2019,9, 3373 7 of 8
Author Contributions:
Conceptualization, S.-M.K.; methodology, K.S. and D.-Y.K.; validation, K.-B.L.; formal
analysis, D.-Y.K.; investigation, K.S.; data curation, S.-M.K.; writing—original draft, S.-M.K.; visualization, K.S.;
supervision, K.-B.L.; project administration, K.-B.L.
Funding:
This research was supported by the Ministry of Trade, Industry & Energy (MOTIE, Korea) under the
Industrial Technology Innovation Program (No. 10062635); and the Institute for Information & Communications
Technology Promotion (IITP) for a grant funded by the Korea government (MSIP) (B0101-19-1081); and Korea
Institute for Advancement of Technology (KIAT) through the National Innovation Cluster R&D program (P0006691);
the Technology Innovation Program (10077743, Development of handpiece design for air turbine and root canal
treatment) funded By the Ministry of Trade, Industry & Energy(MOTIE, Korea).
Acknowledgments:
The authors thank the researchers of the Advanced Dental Device Development Institute,
Kyungpook National University for their time and contributions to the study.
Conflicts of Interest:
The authors declare no conflicts of interest. The funders had no role in the design of the
study; in the collection, analyses, or interpretation of the data; in the writing of the manuscript, or in the decision
to publish the results.
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2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution
(CC BY) license (http://creativecommons.org/licenses/by/4.0/).
... Digital technology has made prosthodontic treatment outcomes more predictable with precise planning and execution. [1,2] Full digital workflow aids in flapless implant placement, ease of impression-making, and high-quality restorations due to higher standardization and reproducible results. [3,4] The steps involve radiographic imaging, transfer of Digital Imaging and Communications in Medicine (DICOM) files to surgical planning software, guided dental implant placement, digital scanning, laboratory scanning, try-in of a three-dimensional (3D) printed trial prosthesis, and finally, fabrication of computer-aided design (CAD)-computer-aided manufacturing (CAM)-based definitive prosthesis. ...
... Not all IOS can be implemented for edentulous arch scanning. [1,9] In edentulous conditions, intraoral scanned impressions are not always a viable option. Still, their accuracy depends on multiple variables such as interimplant distance, surface irregularities, mobility of mucosa, scan body type, and operator experience. ...
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The literature documents the implementation of digital workflow for rehabilitating edentulous conditions with implant-supported prostheses. However, various factors limit its implementation in completely edentulous conditions, especially in impression-making and jaw relations recording. This clinical case report describes rehabilitating a completely edentulous patient with an implant-supported prosthesis using a comprehensive digital workflow. Furthermore, it provides an overview of the technical difficulties and limitations of the technology during the process.
... The dental status at the time of the primary consultation was as follows: 16 with occlusal caries, 55 with occlusal caries and abraded occlusal surface, 54, 53 and 52 affected by abrasion, 11 and 21 without pathological changes, 62 and 63 abraded, 64 with occlusodistal caries and abraded occlusal surface, and 26 with old occlusal filling and secondary caries. The missing teeth in the upper arch were 12,13,14,15,17,22,23,24,25 From an esthetic standpoint, a low smile line, uneven gingival margins, spaces and incorrect axial inclination of the frontal teeth were present. The position of the Stomion point regarding the incisor position was acceptable. ...
... The placement of implants in edentulous patients must be very precise to eliminate lesions of nearly located structures (vessels and nerves) [23][24][25]. Therefore, pretreatment planning is as important as the surgical part of the insertion [26]. ...
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Dental agenesis is one of the most common developmental anomalies in humans and it is frequently associated with several other oral abnormalities. The present case describes non-familial agenesis of permanent teeth in a twenty-one-year-old boy with no apparent systemic abnormalities. The treatment included a personalized and interdisciplinary approach involving endodontics, orthodontics, implant-supported restorations and prosthetic treatments. The treatment plan was thoroughly elaborated using photographic analysis, study models, orthopantomogram, CBCT and cephalograms. Virtual smile design, diagnostic waxing and mock-ups previsualized the treatment objectives. The edentulous spaces were reconstructed by inserting dental implants and monolithic zirconia implant-supported restorations. The final results showed a highly esthetic and functional rehabilitation. Periodic check-ups have shown that the stability of the result is well maintained and that the implant-supported restorations are an optimal solution for patients with multiple anodontia.
... The placement of implants in edentulous patients must be very precise to eliminate lesions of nearly located structures (vessels and nerves) [23][24][25]. Therefore, pre-treatment planning is as important as the surgical part of the insertion [26]. ...
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Dental agenesis is one of the most common developmental anomaly in humans and it is frequently as-sociated with several other oral abnormalities. The present case describes nonfamilial agenesis of per-manent teeth in a twenty-one-year-old boy, with no apparent systemic abnormalities. The treatment in-cluded a personalized and interdisciplinary approach by the means of endodontics, orthodontics, im-plants supported restorations and prosthetic treatments. The treatment plan was thoroughly elaborated using photographic analysis, study models, orthopantomogram, CBCT and cephalograms. Virtual smile design, diagnostic waxing, and mock-up previsualized the treatment objectives. The edentulous spaces were reconstructed by inserting dental implants, and monolithic Zirconia implant supported restorations. The final results showed a highly aesthetic and functional rehabilitation. Periodic checkups have shown that the stability of the result is well maintained and that the implant supported restorations are an op-timal solution for patients with multiple anodontia.
... [3][4][5] Adoption of computer-aided design (CAD)-computer-aided manufacturing has ushered an era of minimally invasive implantology which is fast, highly accurate, and reliable. [6][7][8][9][10] Hence, full-mouth rehabilitation with implants has become simplified and predictable. ...
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Surgical guides (SGs) have been commonly used in full-mouth rehabilitation and numerous advances have been adopted in their development. However, they have been restricted to implant placement and are later rendered useless. They further add to the burden of biological waste management following their limited use. The quantum of technologies and materials used to make us ponder if they can be used further. This article establishes different ways of using SG in different stages of prosthetic phase of treatment by demonstrating the procedures clinically. It gives us an insight into how the guides can be used for implant localization and exposure during the secondary surgical phase and also during impression making, thereby enhancing the treatment outcome.
... The STL file of the planned implant placement used Geomagic Control software. This software has been used in many similar implant placement comparison studies and was found to be reliable [23]. The Geomagic software was also be used to verify the accuracy of the model that has been overlaid so that any deviation detected is because of implant placement as opposed to any inaccuracies in the model manufacture process. ...
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An increase in the number of implants placed has led to a corresponding increase in the number of complications reported. The complications can vary from restorative complications due to poor placement to damage to collateral structures such as nerves and adjacent teeth. A large majority of these complications can be avoided if the implant has been placed accurately in the optimal position. Therefore, the aim of this in vitro pilot study was to investigate the effect of freehand (FH) and fully guided (FG) surgery on the accuracy of implants placed in close proximity to vital structures such as the inferior alveolar nerve (IAN). Cone-beam computed tomography (CBCT) and intraoral scans of six patients who have had previous dental implants in the posterior mandible were used in this study. The ideal implant position was planned. FG surgical guides were manufactured for each case. In this study, the three-dimensional 3D printed resin models of each of the cases were produced and the implants placed using FG and FH methods on the respective models. The outcome variables of the study, angular deviations were calculated and the distance to the IAN was measured. The mean deviations for the planned position observed were 1.10 mm coronally, 1.88 mm apically with up to 6.3 degrees’ angular deviation for FH surgery. For FG surgical technique the mean deviation was found to be at 0.35 mm coronally, 0.43 mm apically with 0.78 degrees angularly respectively. The maximum deviation from the planned position for the apex of the implant to the IAN was 2.55 mm using FH and 0.63 mm FG. This bench study, within its limitations, demonstrated surgically acceptable accuracy for both FH and FG techniques that would allow safe placement of implants to vital structures such as the IAN when a safety zone of 3 mm is allowed. Nevertheless, a better margin of error was observed for FG surgery with respect to the angular deviation and controlling the distance of the implant to the IAN using R2 Gate® system.
... Therefore, the accuracy of the surgical guide is an important factor for the success of implant surgery [18]. In order to improve the accuracy of the surgical guide, there have been many studies to improve the accuracy of cone-beam computed tomography and intraoral impressions, and the accuracy of registration in software [19][20][21][22]. However, there are still insufficient studies to compensate for the shrinkage of the guide hole due to the shrinkage of the light-polymerized resin for 3D printing. ...
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A dental implant surgical guide fabricated by 3-dimensional (3D) printing technology is widely used in clinical practice due to its convenience and fast fabrication. However, the 3D printing technology produces an incorrect guide hole due to the shrinkage of the resin materials, and in order to solve this, the guide hole is adjusted using a trimmer or a metal sleeve is attached to the guide hole. These methods can lead to another inaccuracy. The present method reports a technique to compensate for a decreased guide hole caused by shrinkage that can occur when a computer-guided implant surgical guide is fabricated with a 3D printer. The present report describes a technique to adjust the size of the guide hole using a free software program to identify the optimized guide hole size that is fabricated with the 3D printer.
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Purpose Three-dimensional (3D) printing technologies have gained attention in dentistry because of their ability to print objects with complex geometries with high precision and accuracy, as well as the benefits of saving materials and treatment time. This study aims to explain the principles of the main 3D printing technologies used for manufacturing dental prostheses and devices, with details of their manufacturing processes and characteristics. This review presents an overview of available 3D printing technologies and materials for dental prostheses and devices. Design/methodology/approach This review was targeted to include publications pertaining to the fabrication of dental prostheses and devices by 3D printing technologies between 2012 and 2021. A literature search was carried out using the Web of Science, PubMed, Google Scholar search engines, as well as the use of a manual search. Findings 3D printing technologies have been used for manufacturing dental prostheses and devices using a wide range of materials, including polymers, metals and ceramics. 3D printing technologies have demonstrated promising experimental outcomes for the fabrication of dental prostheses and devices. However, further developments in the materials for fixed dental prostheses are required. Originality/value 3D printing technologies are effective and commercially available for the manufacturing of polymeric and metallic dental prostheses. Although the printing of dental ceramics and composites for dental prostheses is promising, further improvements are required.
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Statement of problem: Conventional radiographic methods are widely used to evaluate the clinical accuracy of implant position. However, such methods require a second computerized tomography (CT) scan and manual registration between presurgical and postsurgical CT data. The alignment errors cannot be calculated. Purpose: The purpose of this clinical study was to introduce a completely digital registration method to evaluate the clinical accuracy of implant position. The digital registration method was then compared with the radiographic method in evaluating accuracy. Some of the alignment errors produced in the digital registration procedures were recorded. Material and methods: A total of 32 implants from 19 patients with sufficient bone volume were enrolled in the study, and all implant surgeries were conducted by one experienced practitioner. Before the surgery, a cone beam computerized tomography (CBCT) scan was made for each patient along with a diagnostic impression to design the ideal implant position using the Simplant software. After the surgery, the postsurgical implant position was determined using an optical scan of the dentition cast and a series of custom registration models (the digital registration method). A simulated cylinder was designed using the Geomagic Studio software to represent the implant, and the deviation of the ideal and postsurgical implant position was calculated. The accuracy evaluated by the 2 methods was also compared. The parameters of the entrance point, apical point, and axis were recorded for each implant. A part of the alignment errors in the digital registration was calculated automatically and recorded. One sample t test and paired t test were conducted by using a statistical software program. Results: The mean deviation between the ideal and postsurgical implant positions evaluated using the digital registration method was 0.84 ±0.57 mm for the entrance point, 1.03 ±0.78 mm for the apical point, and 4.52 ±2.37 degrees for the angulation. No significant difference was found between the accuracy evaluated by the digital registration method and the radiographic method (P>.05). In the digital registration procedure, the alignment error was 0.03 mm for the registration model and 0.29 mm for the dentition. Significant differences were found in the alignment procedure of the impression cylinder (P<.001) and dentition (P<.001). The average positive and negative errors were +0.09 and -0.19 mm for the simulated cylinder of the ideal implant and +0.08 and -0.15 mm for the simulated cylinder of the postsurgical implant. Conclusions: The precision of the digital registration method could be accepted in clinical applications. No significant difference was found between the digital registration method and the radiographic method in evaluating the clinical accuracy of the implant position. The digital registration method was able to control and minimize the alignment errors produced during data processing.
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Objectives To assess the literature on the accuracy of static computer‐assisted implant surgery in implant dentistry. Materials and Methods Electronic and manual literature searches were conducted to collect information about the accuracy of static computer‐assisted implant systems. Meta‐regression analysis was performed to summarise the accuracy studies. Results From a total of 372 articles. 20 studies, one randomised controlled trial (RCT), eight uncontrolled retrospective studies and 11 uncontrolled prospective studies were selected for inclusion for qualitative synthesis. A total of 2,238 implants in 471 patients that had been placed using static guides were available for review. The meta‐analysis of the accuracy (20 clinical) revealed a total mean error of 1.2 mm (1.04 mm to 1.44 mm) at the entry point, 1.4 mm (1.28 mm to 1.58 mm) at the apical point and deviation of 3.5°(3.0° to 3.96°). There was a significant difference in accuracy in favour of partial edentulous comparing to full edentulous cases. Conclusion Different levels of quantity and quality of evidence were available for static computer‐aided implant surgery (s‐CAIS). Based on the present systematic review and its limitations, it can be concluded that the accuracy of static computer‐aided implant surgery is within the clinically acceptable range in the majority of clinical situations. However, a safety marge of at least 2 mm should be respected. A lack of homogeneity was found in techniques adopted between the different authors and the general study designs.
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PURPOSE The aim of this clinical study was to assess the accuracy of the implants placed using a universal digital surgical guide. MATERIALS AND METHODS Among 17 patients, 28 posterior implants were included in this study. The digital image of the soft tissue acquired from cast scan and hard tissue from CBCT have been superimposed and planned the location, length, diameter of the implant fixture. Then digital surgical guides were created using 3D printer. Each of angle deviations, coronal, apical, depth deviations of planned and actually placed implants were calculated using CBCT scans and casts. To compare implant positioning errors by CBCT scans and plaster casts, data were analyzed with independent samples t-test. RESULTS The results of the implant positioning errors calculated by CBCT and casts were as follows. The means for CBCT analyses were: angle deviation: 4.74 ± 2.06°, coronal deviation: 1.37 ± 0.80 mm, and apical deviation: 1.77 ± 0.86 mm. The means for cast analyses were: angle deviation: 2.43 ± 1.13°, coronal deviation: 0.82 ± 0.44 mm, apical deviation: 1.19 ± 0.46 mm, and depth deviation: 0.03 ± 0.65 mm. There were statistically significant differences between the deviations of CBCT scans and cast. CONCLUSION The model analysis showed lower deviation value comparing the CBCT analysis. The angle and length deviation value of the universal digital guide stent were accepted clinically.
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Purpose: The use of tooth-supported static stereolithographic guides has greatly improved the ability to ideally place implants. This study was designed to determine the accuracy of in office-printed implant surgical guides. Materials and methods: Using 3shape Implant Studio, a treatment plan for implant placement for tooth 8 was developed using a digital intraoral scan from a Trios scanner and cone-beam computed tomography. Ten stereolithographic guides were printed using a Form2 3-dimensional printer. Pre- and post-implant insertion digital scans were used to determine distance and angulation differences in the mesiodistal and faciolingual positions of the implants compared with the planned position. Results: The mean difference in mesiodistal direction at the alveolar crest between planned implants and placed implants was 0.28 mm (range, 0.05 to 0.62 mm) and the difference in the faciolingual direction was 0.49 mm (range, 0.08 to 0.72 mm). The mean mesiodistal angulation deviation was 0.84° (range, 0.08° to 4.48°) and the mean faciolingual angulation deviation was 3.37° (range, 1.12° to 6.43°). Conclusions: In-office fabricated stereolithographic implant surgical guides show similar accuracy to laboratory- or manufacturer-prepared guides. This technique provides a convenient and cost-effective means of assuring proper implant placement.
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Purpose: The purpose of this study is to assess the relationship between the time spent designing custom abutments and repeated learning using dental implant CAD software. Materials and methods: The design of customized abutments was performed four stages using the 3DS CAD software and the EXO CAD software, and measured repeatedly three times by each stage. Learning effect by repetition was presented with the learning curve, and the significance of the reduction in the total time and the time at each stage spent on designing was evaluated using the Friedman test and the Wilcoxon signed rank test. The difference in the design time between groups was analyzed using the repeated measure two-way ANOVA. Statistical analysis was performed using the SPSS statistics software (P < 0.05). Results: Repeated learning of the customized abutment design displayed a significant difference according to the number of repetition and the stage (P<0.001). The difference in the time spent designing was found to be significant (P<0.001), and that between the CAD software programs was also significant (P=0.006). Conclusion: Repeated learning of CAD software shortened the time spent designing. While less design time on average was spent with the 3DS CAD than with the EXO CAD, the EXO CAD showed better results in terms of learning rate according to learning effect. Key words: repeated learning; learning curve; CAD software; customized abutment; learning rate
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This technique allows evaluation of the accuracy of a dental implant’s position after computer-guided implant surgery without postoperative radiography. Once the scanned implant and scan body file were prepared, the position of the placed implant was verified by using computer-guided implant software instead of radiography, thus reducing exposure to radiation.
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This report describes a proof of concept for fabricating an interim complete removable dental prosthesis with a digital light processing 3-dimensional (3D) printer. Although an in-office 3D printer can reduce the overall production cost for an interim complete removable dental prosthesis, the process has not been validated with clinical studies. This report provided a preliminary proof of concept in developing a digital workflow for the in-office additively manufactured interim complete removable dental prosthesis. © 2018 Editorial Council for the Journal of Prosthetic Dentistry
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Objectives: To optimize the 3D printing of a dental material for provisional crown and bridge restorations using a low-cost stereolithography 3D printer; and compare its mechanical properties against conventionally cured provisional dental materials. Methods: Samples were 3D printed (25×2×2mm) using a commercial printable resin (NextDent C&B Vertex Dental) in a FormLabs1+ stereolithography 3D printer. The printing accuracy of printed bars was determined by comparing the width, length and thickness of samples for different printer settings (printing orientation and resin color) versus the set dimensions of CAD designs. The degree of conversion of the resin was measured with FTIR, and both the elastic modulus and peak stress of 3D printed bars was determined using a 3-point being test for different printing layer thicknesses. The results were compared to those for two conventionally cured provisional materials (Integrity(®), Dentsply; and Jet(®), Lang Dental Inc.). Results: Samples printed at 90° orientation and in a white resin color setting was chosen as the most optimal combination of printing parameters, due to the comparatively higher printing accuracy (up to 22% error), reproducibility and material usage. There was no direct correlation between printing layer thickness and elastic modulus or peak stress. 3D printed samples had comparable modulus to Jet(®), but significantly lower than Integrity(®). Peak stress for 3D printed samples was comparable to Integrity(®), and significantly higher than Jet(®). The degree of conversion of 3D printed samples also appeared higher than that of Integrity(®) or Jet(®). Significance: Our results suggest that a 3D printable provisional restorative material allows for sufficient mechanical properties for intraoral use, despite the limited 3D printing accuracy of the printing system of choice.
Article
Objectives To systematically review the current dental literature regarding clinical accuracy of guided implant surgery and to analyze the involved clinical factors. Material and Methods PubMed and Cochrane Central Register of Controlled Trials were searched. Meta-analysis and meta-regression analysis were performed. Clinical studies with the following outcome measurements were included: (1) angle deviation, (2) deviation at the entry point, and (3) deviation at the apex. The involved clinical factors were further evaluated. Results Fourteen clinical studies from 1951 articles initially identified met the inclusion criteria. Meta-regression analysis revealed a mean deviation at the entry point of 1.25 mm (95% confidence interval [CI]: 1.22-1.29), 1.57 mm (95% CI: 1.53-1.62) at the apex, and 4.1° in angle (95% CI: 3.97-4.23). A statistically significant difference (P < .001) was observed in angular deviations between the maxilla and mandible. Partially guided surgery showed a statistically significant greater deviation in angle (P < .001), at the entry point (P < .001), and at the apex (P < .001) compared with totally guided surgery. The outcome of guided surgery with flapless approach indicated significantly more accuracy in angle (P < .001), at the entry point (P < .001), and at apex (P < .001). Significant differences were observed in angular deviation based on the use of fixation screw (P < .001). Conclusions The position of guide, guide fixation, type of guide, and flap approach could influence the accuracy of computer-aided implant surgery. A totally guided system using fixation screws with a flapless protocol demonstrated the greatest accuracy. Future clinical research should use a standardized measurement technique for improved accuracy.