Trial of a CAD/CAM system for fabricating complete dentures.
ABSTRACT The purpose of this study was to evaluate the fabrication of a complete denture using a CAD/CAM system. Cone beam CT was used to measure the complete denture and the artificial teeth. After a 3D complete denture image was structured using 3D CAD software, we factored out the artificial teeth and obtained a 3D denture base image. A machining center cut an acrylic resin block, and fabricated an acrylic complete denture base. The artificial teeth were bonded to the cut denture base using resin cement. A 3D digitizer digitized the fabricated acrylic denture. We measured the deviations between the master 3D complete denture image and the 3D data of the fabricated acrylic denture. The average deviations from the master 3D image were 0.50 mm for the occlusal surface. This present study indicates that it is possible to fabricate a complete denture using a CAD/CAM system.
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ABSTRACT: In prosthodontics, conventional methods of fabrication of oral and facial prostheses have been considered the gold standard for many years. The development of computer-aided manufacturing and the medical application of this industrial technology have provided an alternative way of fabricating oral and facial prostheses. This narrative review aims to evaluate the different streams of computer-aided manufacturing in prosthodontics. To date, there are two streams: the subtractive and the additive approaches. The differences reside in the processing protocols, materials used, and their respective accuracy. In general, there is a tendency for the subtractive method to provide more homogeneous objects with acceptable accuracy that may be more suitable for the production of intraoral prostheses where high occlusal forces are anticipated. Additive manufacturing methods have the ability to produce large workpieces with significant surface variation and competitive accuracy. Such advantages make them ideal for the fabrication of facial prostheses.International Journal of Dentistry 01/2014; 2014:783948.
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ABSTRACT: Conventional complete denture prosthetics require several appointments to register the maxillomandibular relationship and evaluate the esthetics. The fabrication of milled complete dental prostheses with digital scanning technology may decrease the number of appointments. The step-by-step method necessary to obtain impressions, maxillomandibular relation records, and anterior tooth position with an anatomic measuring device is described. The technique allows the generation of a virtual denture, which is milled to exact specifications without the use of conventional stone casts, flasking, or processing techniques.The Journal of prosthetic dentistry 01/2014; · 1.22 Impact Factor
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ABSTRACT: Recently, computer-aided design/computer-aided manufacturing (CAD/CAM) technology has been applied to the field of removable complete denture prosthodontics. We developed a system for fabricating complete dentures applying CAD/CAM technology. In this system, artificial teeth were bonded to the recesses of a milled denture base. However, the offset values needed for the recesses are not known. The purpose of the present study was to evaluate the accuracy of bonded artificial teeth positions in 0.00 (control), 0.10, 0.15, 0.20, and 0.25 mm offset recess groups. Four types of artificial teeth, upper left central incisor (UL1), upper left canine (UL3), upper left first premolar (UL4), and upper left first molar (UL6), were used. Each type of artificial tooth was arranged at regular intervals on the denture base model with the CAD software. These data were defined as the master data. The artificial teeth parts were subtracted from the denture base model by Boolean logic operations in order to make recesses, and the recesses were then offset in five values. Based on these denture base data, prepolymerized resin blocks were milled (n=3). After bonding artificial teeth on the milled denture base model, a cone beam computed tomography (CBCT) scan was performed to obtain scanned data. Deviations between the master data and the scanned data were calculated. Based on the results, the optimal offset values were found to be 0.15–0.25 mm for UL1, 0.15 and 0.25 mm for UL3, 0.25 mm for UL4, and 0.10–0.25 mm for UL6.Computers in Biology and Medicine. 01/2014;
Dental Materials Journal 2011; 30(1): 93–96
The process of fabricating complete dentures consists of
preliminary impressions, construction of a custom tray,
definitive impressions, construction of occlusion rims,
creating jaw relationship records, arranging prosthetic
teeth, try-in, flasking, resin packing and denture
delivery. This process with so many steps is associated
with certain problems. Methods of denture fabrication
have not progressed substantially for the 70 years since
polymethyl methacrylate was introduced in 19361).
Most importantly, this process is complex and difficult
for dentists. Consequently, it requires experienced
prosthodontists and dental technicians. In addition, it
requires many visits of the patient and a large amount of
laboratory work. Elderly patients in particular can find
the necessity for a lot of hospital visits distressing.
Furthermore, acrylic resins do not fulfill all of the
requirements for hypothetically ideal denture base
The fabrication of complete dentures using a
computer-aided design/computer-aided manufacturing
(CAD/CAM) system has the potential to simplify the
above process and resolve the associated problems. In
recent years, CAD/CAM systems have been successfully
introduced into restorative dentistry and maxillofacial
technology3-6). Moreover, they have been applied to
removable prostheses. For example, Williams et al.7,8)
fabricated removable partial denture frameworks using
CAD/CAM systems. In addition, Kawahata et al.9)
fabricated wax complete dentures using a computerized
numerical control (CNC) machining center and Maeda et
al.10) fabricated the shells of complete dentures using
CAD/CAM systems. To date, however, no studies have
been carried out on the fabrication of complete dentures
as definitive prostheses using CAD/CAM systems.
We formulated a method for the fabrication of
complete dentures using a CAD/CAM system as follows.
First, the dentist reforms the denture worn by the
patient. For example, if the denture is not adapted to the
mucosa, it requires refitting or relining. Similarly, if it
does not have harmonic occlusion, it needs occlusal
adjustment or reconstruction of the occlusal surface.
Second, dental three-dimensional (3D) cone beam
computed tomography (CBCT) scans are performed for
the maxillary and mandibular reformed dentures, which
maintain the maximal intercuspal position, to obtain 3D
morphological data. Third, the 3D data of the reformed
denture are used for the only mucosal surface, and the
CAD application fabricates the morphological data for
the new denture. Upper and lower commercially
available artificial teeth are arranged and a polished
surface is formed on the CAD application. At this time
3D position of maxillary and mandibular denture base
are held on CAD software. The 3D data for the denture
base are structured by removing the artificial teeth.
Fourth, the CAM technology is applied by using the CNC
machining center to cut an acrylic resin block based on
the 3D data for the new denture base to fabricate the
new complete denture base. Bonding of the artificial
teeth, which are selected on the CAD application, to the
denture base finishes the new complete denture. In
addition, the CNC machining center fabricates the
denture by milling. Since this method, which is different
from conventional packing, is not limited to particular
denture base materials, materials that are more ideal for
dentures than acrylic can be used. This method may
resolve the current problems and prove useful in the
fabrication of complete dentures.
This study focused on the CAD/CAM part of this
Trial of a CAD/CAM system for fabricating complete dentures
Manabu KANAZAWA1, Masanao INOKOSHI1, Shunsuke MINAKUCHI1 and Naoto OHBAYASHI2
1Complete Denture Prosthodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima,
Bunkyo-ku, Tokyo 113-8549, Japan
2Oral and Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima,
Bunkyo-ku, Tokyo 113-8549, Japan
Corresponding author, Manabu KANAZAWA; E-mail: firstname.lastname@example.org
The purpose of this study was to evaluate the fabrication of a complete denture using a CAD/CAM system. Cone beam CT was used
to measure the complete denture and the artificial teeth. After a 3D complete denture image was structured using 3D CAD software,
we factored out the artificial teeth and obtained a 3D denture base image. A machining center cut an acrylic resin block, and
fabricated an acrylic complete denture base. The artificial teeth were bonded to the cut denture base using resin cement. A 3D
digitizer digitized the fabricated acrylic denture. We measured the deviations between the master 3D complete denture image and
the 3D data of the fabricated acrylic denture. The average deviations from the master 3D image were 0.50 mm for the occlusal surface.
This present study indicates that it is possible to fabricate a complete denture using a CAD/CAM system.
Keywords: Complete denture, CAD/CAM, Fabricating accuracy
Color figures can be viewed in the online issue, which is avail-
able at J-STAGE.
Received Jul 21, 2010: Accepted Sep 17, 2010
doi:10.4012/dmj.2010-112 JOI JST.JSTAGE/dmj/2010-112
Dent Mater J 2011; 30(1): 93–9694
system that are designing the denture on CAD software
and fabricating the denture the CNC machining center.
The purpose was to evaluate the fabrication of complete
dentures as definitive prostheses using a CAD/CAM
MATERIALS AND METHODS
The one complete denture and the artificial teeth (Real
Crown and Endura Posterio; Shofu, Kyoto, Japan) were
scanned separately using a Dental 3D CBCT System
(Fine Cube; Yoshida, Tokyo, Japan), and a DICOM
viewer (OsiriX; The OsiriX Foundation, Geneva,
Switzerland) processed the 3D morphological STL format
data for the complete denture and the artificial teeth
(Fig. 1). After the 3D CAD software (CATIA V5R19;
Dassault Systemes, Velizy-Villacoublay, France) created
a new 3D complete denture image based on the 3D data
for the complete denture and the artificial teeth (Fig. 2),
the artificial teeth were factored out using Boolean logic
and a 3D denture base image was obtained (Fig. 3). The
3D CAM software (Mastercam; CNC Software Inc.,
Tolland, CT) programmed the cutter path based on the
3D denture base image. A five-axis CNC machining
center (Variaxis 200; Yamazaki Mazak, Aichi, Japan)
cut an acrylic resin block based on the cutter path, and
fabricated one acrylic complete denture base (Fig. 4).
This cutting time was about 150 minutes. The artificial
teeth were bonded to the cut denture base using a resin
cement (Super Bond; Sun Medical, Shiga, Japan) (Fig.
5). A 3D digitizer (Atos; Gom International AG, Widen,
Germany), which is a flexible optical measuring machine
based on the principle of triangulation, digitized the
fabricated acrylic denture. The deviations between the
Fig. 1 3D morphological data for the complete denture
and the artificial teeth.
Fig. 4 Acrylic complete denture base.
Fig. 5 New complete denture.
Fig. 2 3D data for the new complete denture.
Fig. 3 3D data for the new complete denture base.
Dent Mater J 2011; 30(1): 93–96 95
master 3D complete denture image and the 3D data for
the fabricated acrylic denture were measured at all
nodes of polygons by using interchanging 3D measuring
software (Atos Viewer; Gom International AG, Widen,
Germany), which superimposed two 3D-STL data. The
averages of the nodes were calculated for mucosal,
polished and occlusal surface respectively. All the
scanning and digitize was performed one time because
this measuring had high reliability for static objects in
The data for the fabrication accuracy are shown in
Figures 6–8. There was good accuracy for the buccal
polished surface (Figs. 6 and 7). The average deviations
from the master 3D data were about 0.10 mm for this
surface. However, the occlusal surface was fabricated
with lower accuracy. In the artificial teeth part, the
maximum deviation was about 0.88 mm and the average
deviation was 0.50 mm. There was also good accuracy for
the mucosal surface (Fig. 8). The average deviation from
the master 3D data was about 0.10 mm for this surface.
In this new method for the fabrication of complete
dentures using a CAD/CAM system, a Dental 3D CBCT
System was used to digitize the dentures. The reasons
for selecting the Dental 3D CBCT System are as follows.
The CBCT System is equipped with the shortest imaging
times and is easy to operate compared with other
digitizers. In this scanning method, only refined dentures
that maintain the maximal intercuspal position are
scanned quickly. Therefore, not only the 3D morphological
data of the denture space but also the jaw registration
are obtained without exposing the human body to
radiation. Furthermore, the CBCT System will generally
become widely used in dental hospitals and dental offices
in the future.
A five-axis CNC machining center was used to
fabricate the complete denture. There are two types of
manufacturing methods based on 3D data. One method
is rapid prototyping, as typified by selective laser
sintering, stereolithography and 3D printing. The other
method is cutting work using a machining center. The
properties of the definitive prosthesis fabricated by the
five-axis CNC machining center are more suitable for a
denture base compared with rapid prototyping at the
The artificial teeth and denture base are equipped
with different colors and properties. The artificial teeth
need high abrasion resistance and an aesthetic
appearance. It is difficult to cut the artificial teeth from
a single property block. Thus, only the denture base was
fabricated by cutting, and commercially available
artificial teeth were adhered to the denture base. In this
step, a resin cement was used as an adhesive. Currently,
special adhesives with higher adhesive properties than
resin cement are being developed.
A complete denture was designed on a computer,
followed by digitization of the fabricated denture and
measurements of the fabrication accuracy. CAD/CAM
systems have been applied to quality control in the
industrial world, and are well suited for measuring
fabrication accuracy. Large surfaces like the polished
Fig. 6 Results of the accuracy measurements: front view.
Fig. 7 Results of the accuracy measurements: occlusal
Fig. 8 Results of the accuracy measurements: mucosal
Dent Mater J 2011; 30(1): 93–96 96
and mucosal surfaces showed good accuracy. In these
parts, the deviations ranged from 0 to 0.10 mm. These
results indicate that the machining center had sufficient
cutting accuracy and cut the block definitely based on
the 3D data.
In the artificial teeth part, some points showed large
deviations. These large deviations were attributable to
the fact that the artificial teeth and their sockets on the
denture base could have different sizes. This situation
arises for two reasons. The first is shrinkage of the 3D
data when the CT scan is performed. Ballrick and
Baumgaertel11,12) reported that CBCT had a tendency to
underestimate the actual values of each measurement.
This underestimation occurred in 94.4% of the
measurements and the differences were less than 0.1
mm. The second is the smoothing that occurs when 3D
images are processed on the DICOM viewer. Because the
DICOM data scanned from CT images are slice data, the
processed 3D image has a stepped surface. Accordingly,
when the DICOM viewer processes the 3D data, a
smoothing function is used. Surface smoothing can make
the geometry smaller by up to 5%13). Based on the reasons
discussed above, although mucosal surfaces showed good
accuracy, the 3D data of the artificial teeth could be
smaller than the real artificial teeth. Therefore the
artificial teeth did not fit into their sockets on the denture
base. To resolve the above problems, when the DICOM
viewer processes the 3D data, consideration of the
amount of shrinkage or processing without shrinkage
would lead to better accuracy.
The present study indicates that complete dentures
can be fabricated using CAD/CAM systems in the future.
This new method, which breaks from the conventional
method, may lead to simplification of the laboratory
work, shorten chair times and maintain the quality of
treatment. In addition, this molding method can apply
materials that are equipped with innovative properties.
Further studies involving the fabrication of complete
dentures using gingival color resin under conditions that
are closer to clinical circumstances and measurements of
the fabrication accuracy are planned.
The present study indicates that it is possible to fabricate
a complete denture using CAD/CAM systems. However,
since the slight difference between artificial teeth and
sockets on denture base may cause large deviations,
further improvements are needed in processing the 3D
This study was supported by a Grant-in-Aid for Young
Scientists (No. 19791428) from the Ministry of Education,
Culture, Sports, Science and Technology of Japan.
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