Content uploaded by Yuan-Min Lin
Author content
All content in this area was uploaded by Yuan-Min Lin on Nov 16, 2021
Content may be subject to copyright.
199
© e Author(s) 2018
Y.-C. Kim, P.-C. Chen (eds.), e Digitization of Business in China, Palgrave
Macmillan Asian Business Series, https://doi.org/10.1007/978-3-319-79048-0_8
8
Digitalisation inDentistry: Development
andPractices
Yuan-MinLin
8.1 Introduction
Over the past several decades, the dental workow has not changed too
much. Despite its maturity, the conventional “analogue” workow is
time-consuming and labour-intensive. Ever since the introduction of the
dental CAD/CAM (computer-aided design/computer-aided manufac-
turing), the production of dental restoration has become more auto-
mated, as in many other industries. Meanwhile, the term “digital
dentistry” is frequently seen in all kinds of media. Many dental profes-
sionals misunderstand that digital dentistry equals to dental CAD/CAM
technology. In fact, digital dentistry stands for the involvement of the
computer-based tools during diagnosis, recording, communicating and
treatment of patients. Digital dentistry has been the biggest advancement
in the past few years in the dental industry. Numerous articles described
digital dentistry as “paradigm shift” or “revolutionary”; these articles lead
Y.-M. Lin (*)
Department of Dentistry, National Yang-Ming University, Taipei, Taiwan
e-mail: ymlin@ym.edu.tw
200
the patients to believe that digital dental technology is currently the
mainstream of daily dental practices. Despite the generally agreed con-
sensus that digital dentistry is an inescapable trend, surprisingly, less than
10% of dentists in the USA used the intraoral scanner for digital impres-
sion in 2016 (Cowburn and Cowburn 2016).
Digital workow for dental restorations consists of image acquisition,
data processing and digital manufacturing. When it comes to image
acquisition, most people think about digital impression using an intra-
oral scanner or digitalisation of conventional impression using a desktop
scanner. In fact, other image acquisition methods, including cone beam
computed tomography (CBCT), face scanning and even photo taking
using a digital camera, are also widely used in digital dentistry. After
image acquisition, software must be used to create a dental restoration or
appliance based on the “digital models” obtained from image acquisition.
is is also referred to as CAD, or computer-aided design. For example,
the software can be used to create the shape of a single crown or bridge
on the digital die. ere are some free software products for the general
CAD applications. For complex shapes like a single crown or bridges,
paid software is a favoured option as it can hugely smoothen the work-
ow, and its functions are especially designed for dental applications.
After designing the dental restorations or appliances, the three-
dimensional (3D) model les can be sent to a dental laboratory or to the
dentist’s own on-site digital manufacturing system. Digital manufactur-
ing, commonly called computer-aided manufacturing (CAM), can be
divided into subtractive manufacturing and additive manufacturing. e
former refers to computer-numeric-controlled (CNC) milling and the
latter 3D printing. CNC milling has been used in dental applications for
more than two decades, so the mechanical performance, marginal integ-
rity and accuracy of CNC-milled dental restorations are comparable with
conventional solutions (Yao etal. 2014; Penate etal. 2015). ese auto-
mated dental CAM procedures became more cost-eective compared to
conventional dental laboratory cost, especially in the high-wage coun-
tries, such as Western Europe, USA, Australia and Japan.
Before 2017, the digital impression was categorised into “closed sys-
tem” and “open system”. e “closed system” means that the exported le
of the intraoral scanner can only be read by CAD software and a CAM
Y.-M. Lin
201
machine originating from the same company. In contrast, the le coming
from an “open system” intraoral scanner, mostly in STL, PLY or OBJ le
formats, can be read by other CAD software from the “open system”
camp. As the market is getting increasingly competitive and dentists are
unwilling to put all their eggs in one basket, the boundary between open
and closed systems is disappearing. To give an example of Sirona (Dentsply
Sirona, USA) and 3 Shape Trios (3 Shape, Denmark), the former was
long considered as a “closed system” intraoral scanner manufacturer and
the latter previously provided the “pay-to-be-opened” option; however,
recently 3 Shape Trios allowed free exports in the rst half of 2017.
e purpose of this article is to briey describe the technologies used
in digital dentistry and also their inuence on the dental industry until
2017, based on scientic ndings, personal experiences and communica-
tion with the dental communities. e facts outlined in this article may
change over time.
8.2 Digital Impression
Digital impression technology replaced traditional impression proce-
dures, from prior methods of taking an impression using a tray and
impression materials to using intraoral scanners to create the 3D models
of the hard and soft tissues in the mouth. e digital impression system
creates an “electronic impression” that can be forwarded to the dental
laboratory or dentist’s own CAD/CAM system. Because these 3D models
can be displayed on a chairside monitor using various software tools,
dentists can consequently evaluate their preparation quality, such as mar-
gin smoothness, occlusal clearance and preparation taperness. If the prep-
aration is not satisfactory, immediate corrections can be made which can
now save time and money, when prior conventional impressions would
have resulted in a second appointment.
“Digital impressioning” was rst introduced in the mid-1980s when
Sirona Dental System released the CEREC 1 (Mormann 2006) (Sirona
Dental System merged with Dentsply International Inc., to form
Dentsply Sirona in 2015). In 1980, a Swiss dentist Dr. Werner Mörmann
and an Italian electrical engineer, Dr. Marco Brandestini from the
Digitalisation inDentistry: Development andPractices
202
University of Zurich, developed the CEREC method, which stands for
Chairside Economical Restoration of Esthetic Ceramics. e method
was commercialised in 1987 by Siemens as the CEREC 1, the second
CAD/CAM system in dentistry. CEREC 1 was equipped with a 3D digi-
tal scanner and a milling unit to create dental inlays from ceramic blocks
in a single appointment.
During the procedure of conventional impression, problems could hap-
pen due to mould instability over time, for example margin laceration,
when separation and dimensional discrepancy occur between the mould
and the die. Digital impression is a non-contact measuring technology;
therefore, it can overcome the problems associated with the material lac-
eration during conventional impression. Also, almost all the intraoral scan-
ners in the market can provide enough accuracy to meet the clinical needs
(Ender etal. 2016), (Ender and Mehl 2011). A study pointed out that
compared to the additional silicon impression materials, intraoral scanners
only exhibited a slightly lower accuracy. However, the trueness and preci-
sion of the intraoral scanner are still far lower than 120 μm, below which
a tolerance value was generally considered clinically acceptable. Another
study also demonstrated a similar trend (McLean and von Fraunhofer
1971). e intraoral scanner also causes less gagging reex because of the
small scanning tip. Despite all these benets, it must be mentioned that
digital impression cannot replace conventional impression in every case.
For example, traditional impression materials can provide a better result in
situations in which a dry scanning environment cannot be achieved.
e cost was one of the rst barriers for dentists when entering the
world of “digital impression”. In 2016, only a few companies in the world
were manufacturing intraoral scanners, which included 3 Shape (3 Shape
Trios 3, Denmark), Carestream (Carestream CS3600, USA), Dentsply
Sirona (Omnicam, USA), iTero (iTero Element, Israel), Planmeca
(Planmeca PlanScan, Finland) and other small brands. ere was no
major intraoral scanner manufacturer from East Asia and the price of the
intraoral scanner ranged from 30,000 to 100,000 US dollars, although it
was dependant on the software packages. However, it became evident
that regardless of whether dentists intended to have the restorations made
in the external laboratory or use their own CAD/CAM system, an invest-
ment in digital impression system must be made. ankfully, erce com-
Y.-M. Lin
203
petition between the companies made the market more liberalised and,
consequently, the cost of the digital impression system has dropped sig-
nicantly in the past two years. e price of the digital impression system
has now dropped to a range that most dentists “would consider” buying
one. It can therefore be expected that in the developed countries and in
some developing countries, the digital impression system will eventually
be embraced by most of the dentists. In Taiwan, it was observed that
younger dentists are more prone to quickly embrace the new technology
while senior dentists are more hesitant to enter the digital world in the
beginning due to the lack of familiarity with regards to recent technologi-
cal advances. However, as times are advancing, it seems rational to sug-
gest that the uptake of new technology is only going to get greater.
Like many other digital products, it is always risky to buy the latest
digital dental products immediately after they are released because they
are typically sold without having been tested extensively. A similar sce-
nario can be seen in the computer software, most of which is eld-tested
by the consumer rather than being debugged by the developers. Luckily,
the calculating power and post-processing need for the image acquisition
heavily rely on the computer which the intraoral scanner is connected to.
erefore, the bugs of a newly released digital impression system can be
xed by a simple software update.
e latest model of many intraoral scanners can scan the objects in
colour. Colour scanning makes the scanned model more realistic and
clearer with the margin location. Blood or saliva contamination during
scanning can be easily dierentiated in a colour-scanned model, while in
a monochrome model, the uid contamination cannot be dierentiated
which consequently results in inferior accuracy. Another benet of the
colour scanner is the potential in shade matching. Currently, shade
matching of patient’s teeth with the shade guide, which is the colour
reference provided by dental material suppliers, relies heavily on the
naked eye or the digital camera. Because the colour of a tooth is not
homogenous, if the intraoral scanner can record colour distribution and
then match the shade in the same scanning procedure, it will save lots of
clinical time for shade matching. Matching shade usage in the intraoral
scanner is still in its preliminary stages; shade matching using conven-
tional shade matching procedures is still more accurate at this time. ere
Digitalisation inDentistry: Development andPractices
204
is still a long way to go before the accuracy of the intraoral scanner shade
matching can be considered clinically acceptable.
8.3 CAD forProsthetic Restorations
For dental CAD, not too many software products are available in the
world. Exocad DentalCAD, CEREC software (Sirona) and 3 Shape Dental
System are among the most used dental CAD software products in the
world. Other companies, such Carestream, Planmeca, iTero and others,
also have dental CAD software products but with low market shares.
Exocad is a dental software company worth noticing. Unlike CEREC and
3 Shape, Exocad is a small company specialising in dental CAD/CAM,
and it does not have its own hardware products. Exocad collaborates with
quite a few hardware companies as the OEM (original equipment manu-
facturer) for their CAD software. Because of this reason, Exocad grew rap-
idly in the past few years and has a huge user base. Many digital dental
laboratories in Taiwan use Exocad DentalCAD for their daily works.
Because of its popularity and simplicity, some dental schools, including
Department of Dentistry, National Yang-Ming University, where the
author is working, taught undergraduate students to used Exocad
DentalCAD in the digital dentistry course. CAD software can not only be
used to design xed restoration such as crown and bridges, it can also be
used to design prostheses such as a removable partial denture, complete
denture, occlusal splint and implant abutments. Moreover, some CAD
software provides the simulation of jaw movement with a virtual articula-
tor. Targeting dierent users, most CAD software have a dentist version
and a dental technician version. In most cases, the former is a simplied
version of the full functional dental technician version.
One functionality that almost every CAD software is adding into their
features is DSD, Digital Smile Design. DSD is a working philosophy for
dentists to present what the patients will look like after the whole treat-
ment using photographic tools. A dentist can design the shape, calculate
the ratio and pick up the colour of the anterior teeth of a patient using
either database or manual drawing. It is a communication tool between
the dentist, the patient and the technician. If the patient is happy with
Y.-M. Lin
205
the dentist’s design, the technician can fabricate the diagnostic wax-up or
provisional restorations according to the design from the dentist for the
clinical try-in process. Even though the DSD process can be presented in
2D using a standard presentation software such as PowerPoint (Microsoft,
Washington, USA) or Keynote (Apple, California, USA), integrating this
feature in the CAD software can smoothen the DSD workow and pres-
ent the patient’s future appearance in a 3D manner. Not only is the
patient’s future teeth present, the soft tissue, including the later prole
and the lip position of the patient, can also be simulated. ere are two
available applications that can implement the Augmented Reality tech-
nology to present the “after treatment” smile of the patients using a tab-
let: Kapanu app and QuicSmile app. e former is a spin-o company
from ETH Zürich. It was acquired by the dental material giant Ivoclar
Vivadent in 2017. e latter was developed by an innovation team named
“Glamofy” from the electronics company ASUS.Using the machine
learning database, both DSD software can detect the intraoral area and
replace the current dentition with the “after treatment” image, without
the need for manual selection and replacement. However, neither soft-
ware has been integrated with any CAD software yet; therefore, the “after
treatment” smile could not be 100% recreated by restorations.
8.4 CAM Using CNC Milling Machine
CAM can be divided into two categories: subtractive manufacturing and
additive manufacturing. Subtractive manufacturing means that the den-
tal restorations, including crowns, bridges, inlays, onlays, veneers, occlu-
sal splints, dental implant restorations, removable dentures and
orthodontic appliances, are milled from solid blocks (or discs) of
materials.
As described previously, the technology behind the CAD/CAM sys-
tem is really mature. In the 1940s to 1950s, the rst numerically con-
trolled machines were invented. e machines utilising a punched tape
to provide information for the positions work on machine tools. In the
1960s, technology advanced rapidly so that early computer systems were
implemented in manufacturing the parts of automobiles and aeroplanes
Digitalisation inDentistry: Development andPractices
206
(Weisberg 2008). Professor Francois Duret, a French dentist introduced
CAD/CAM concepts into the dental world in the thesis written at the
Université Claude Bernard Lyon, entitled “Empreinte Optique” (Optical
Impression) in 1973 (Duret 1990). Professor Duret submitted a patent
entitled “Method of and Apparatus for Making a Prosthesis, Especially a
Dental Prosthesis” (US Patent #4,663,720) in 1984. In the Chicago
Midwinter Meeting in 1989, Professor Duret brought his CAD/CAM
system and did a live demonstration, in which he successfully made a
crown in four hours (Duret 1990).
Nowadays, the time to mill a ceramic crown from a block can be as
short as 15 minutes. With an in-house digital impression, CAD and
CNC milling system, the dentist can achieve a “one-day dental crown”.
In the conventional workow, a patient has to wear temporary restora-
tion for several days to even several weeks and visit the dentist again for
the nal prosthesis. e “one-day dental crown” saves not only the chair
time of a dentist but also the time for patients and technicians. In Taiwan,
many dental clinics used the “one-day dental crown” as the marketing
strategy and were very successful. Patients who were not satised with the
aesthetic of their teeth were more willing to visit clinics that oered the
“one-day dental crown” because of the shorter treatment period. In addi-
tion, those patients who were not satised with their aesthetic had a ten-
dency to have more than one crowns or veneers placed. As a result, more
revenue was made.
e materials used for dental CNC milling can be polymers, ceram-
ics, metals or even composite materials. Milling of polymers, ceramics
and composite materials can be done by an entry-level CNC miller,
while milling of metal requires large milling power; thus it is usually
very expensive and only available in the dental laboratory. In order to
compete with the conventional prosthetic materials, the materials for
CNC milling must be both functional and “aesthetically” pleasing.
Over the past decade, the materials for CNC milling have evolved dra-
matically. Here, we take ceramics as an example. Feldspar porcelain,
commonly used for PFM (porcelain fused to metal) crown and bridge,
was made in the form of a block by many material suppliers for CNC
milling. For better aesthetic, feldspar blocks with three or four colour
Y.-M. Lin
207
gradients, for example Vita Triluxe and Vita Triluxe Forte, were oered.
ese gradient blocks provided colours that could simulate the colour
change of a natural tooth from the incisal edges to the cervical third.
e location of the colour gradients on the milled crown or veneers can
be designed in the CAM software. Another material that is increasingly
becoming popular is zirconium dioxide (or zirconia), also called ceramic
steel. Zirconia is a high- strength material but has been complained
about for its opacity and whiteness. erefore, zirconia was not used in
the aesthetic zone not long ago. By keeping the structure of zirconia at
the cubic phase, scientists have developed the high-translucency zirco-
nia, and they have been getting more popular recently. Like the gradi-
ent feldspar materials, gradient zirconia discs are now available in the
market, including KATANA Zirconia HT, LAVA plus and Zirkozahn
Prettau to name a few.
8.5 CAM Using 3D Printing
CNC milling is a popular technology, and numerous companies supply
CNC milling machines for dental applications. A disadvantage of milling
technologies is that they are less capable of carving complex details such
as undercuts and inner-geometry. e detail of the milled products is
determined by the diameter of the smallest milling tool a milling machine
uses. Furthermore, it can only produce one unit at a time. Additive man-
ufacturing, in contrast, is capable of building complex geometric features
and much more at a productive rate, if large quantities of products are
needed. Additive manufacturing, also known as 3D printing, has been
used for rapid prototyping of industrial products for almost three decades.
In 1984, the rst patent for the stereolithography process was led in
France (Andre 1984). A few months later, 3D System Corporation led
another stereolithography patent which described a way to cure photo-
polymers layer by layer using ultraviolet light (Hull 1986).
Ever since former US president Barack Obama referred to 3D printing
technology as the technology that has the “potential to revolutionise the
way we make almost everything” (2013), 3D printing became well known
Digitalisation inDentistry: Development andPractices
208
by many dental professionals. By 2017, most of the dental restorations
and dental appliances could be made by 3D printing, despite some of
them being pricey compared to its counterpart made by CNC milling or
by conventional manufacturing procedures. For example, 3D printing of
zirconium dioxide crown and bridge is possible by inkjet printing glue to
bind zirconium dioxide powders followed by high-temperature sintering
at 1700°C.is technique is very rare, and the surface smoothness of the
printed model is still not satisfactory. Zirconium dioxide crown and
bridge made by CNC milling is a mature technique, and the material
cost for each crown can be as low as 5 US dollars. Another example is
base metal. Base metal is a commonly used material for low-cost crowns
and bridges. 3D printing and CNC milling of base metals are possible,
while the cost of both techniques is far higher than the wax-up and cast-
ing of base metal using a conventional method.
ere are many types of 3D printing technology that can be used for
dental applications, such as Selective Laser Sintering (SLS), inkjet print-
ing, Stereolithography Apparatus (SLA), Digital Light Processing (DLP)
and Fused Deposition Modelling (FDM). SLS is a technique for metal
3D printing. It requires a high-power laser source to emit the laser beam
on the metal powder and sinter the metal powder in situ. A high-power
laser source is very pricey, so an SLS printer can cost more than 300,000
US dollars. erefore, only large dental laboratories have enough cases
and are able to aord one. e inkjet printing technology is a developing
technology that can be used to print ceramic materials in the future. e
principle of this technology is to print binder from a Piezoelectric Printing
head to bind ceramics powders together. After burning and sintering in
the oven, a ceramic restoration can be obtained. is technology is still
under development and is currently not used in the dental industry.
DLP and SLA are the two most commonly used technologies in dental
3D printing. Both techniques are used to print resin, but the DLP uses a
projector while the SLA uses a laser as the light source to cure the photo-
polymerisable resin. e projector equipped with a DLP 3D printer proj-
ects black and white masks, which correspond to the shape of the slices of
the object to be printed, layer by layer. In contrast, an SLA 3D printer
emits a laser beam at once, and for each layer, it takes time for the laser
Y.-M. Lin
209
beam to form a 2D mask from a dot. When the light in DLP or SLA 3D
printer irradiates on the photopolymerisable resin, the initiator in the
resin is activated and initiates the photopolymerisation, so the resin can
turn into a solid from a liquid.
e reason why DLP and SLA 3D printers interest dentists are because
resin can be used for so many dental applications, including provisional
restorations, denture base, occlusal splint, surgical guides, dental models
and even models for clear aligner. In view of the potential of DLP and
SLA 3D printers, many 3D printing companies already well known in
the industry and the DIY markets have entered the dental market, for
example 3D Systems, Stratasys, EnvisionTech, DWS and Formlabs.
Among all the products released by these companies, Form 2, Formlabs’
latest 3D printing model, gained a lot of attention from the dental com-
munity. e market price of the printer from Form 2 is only 3499 US
dollars, which is a price that almost all dentists and dental technicians can
aord. Furthermore, the recent partnership with 3 Shape in 2017 makes
Form 2 seamlessly integrated with 3 Shape’s CAD/CAM software. In
Taiwan, two electronics companies, Young Optics and Delta Electronics,
entered the dental 3D printing industry. Young Optics is a professional
company with a focus on the light engine of projectors. It not only man-
ufactured and sold 3D printers under its brand MiiCraft, but also allowed
other 3D printing companies to sell the same MiiCraft 3D printers under
their respective brand names. Delta Electronics is the largest company in
power supply manufacturing. Its 3D printer debuted in 2017, and will be
available on the dental market by the end of 2018.
In addition to the 3D printer manufacturers, there are also companies
who benet from 3D printing techniques. Align Technology’s brand
“Invisalign” is the leading brand in the clear aligner market. e idea of
the clear aligner is to simulate a series of teeth movements from their
original position to a well-straightened dentition, and these simulated
dentitions are printed from the 3D printer. An elastic thermoplastic
material is heated and pressurised onto the 3D-printed models to form
clear aligners. For a whole clear aligner treatment, around 100 clear align-
ers are needed. Furthermore, the printed 3D models for clear aligner
applications do not have to be as accurate as the 3D models for the dental
Digitalisation inDentistry: Development andPractices
210
prosthetic applications. erefore, it has a lower entry barrier and thus a
big market for the 3D printing industry.
8.6 CBCT andImplant Planning Software
Dentists have been using 2D periapical and panoramic radiography for
decades. e problems of the 2D radiography system are its inherent
distortion factors and the inability to demonstrate 3D spatial anatomical
structures. e early 3D radiographic imaging systems introduced into
dentistry were medical-grade CT, which were very expensive and required
a high dose of radiation. CBCT provides information on 3D anatomic
structures, quantity and quality of bone, and the location of blood vessels
and nerves. It requires a comparatively lower radiation dose as compared
to conventional CT scans. During imaging, the CBCT scanner rotates
around the patient’s head for around 200 degrees; meanwhile, a cone-
shaped source of X-ray radiation is projected through the area of interest
onto an X-ray detector on the opposite side to obtain a few hundred
sequential planar projection images of the eld of view (FOV) for further
reconstruction. e reconstructed 3D digital images are composed of
“voxels” of the anatomic data. Unlike the intraoral and desktop scanner,
CBCT saves les in DICOM (Digital Imaging and Communications in
Medicine) format. DICOM is a standard for medical images and is used
in almost all hospitals worldwide. Any standard DICOM le can be
exchanged across hospitals and dental clinics. erefore, CBCT serves as
a powerful tool for practices, dental laboratories and image centres. With
so many advantages, it is gradually becoming part of the standard proce-
dures for implant dentistry, orthodontic procedures, wisdom tooth
removal surgery and even endodontic procedures. In the dental market,
there are many CBCT manufacturers, including Carestream, Planmeca,
Imaging Sciences International, Sirona and Gendex Dental Systems. All
these companies provide CBCT with comparable resolutions and soft-
ware functions.
For a dentist who does not have much experience in implant surgery,
it is hard to place an implant with the correct angulation. Even for
Y.-M. Lin
211
experienced periodontists, errors on the implant angulation can occa-
sionally occur that damage important anatomic structures, such as the
inferior alveolar nerves and maxillary sinus. With CBCT, implant loca-
tion, implant diameter, implant length and the angulation of the
implant placement can be planned using implant planning software,
such as Simplant® (DENTSPLY Implants), NobelClinician® (Nobel
Biocare), Invivo5 (Anatomage), TxStudio™ (i-CAT), coDiagnostiX™
(Dental Wings), Planmeca Romexis® (Planmeca) and Blue Sky Plan
(BlueSkyBio) to name a few.
e implant planning software allows dentists to visualise the simu-
lated implant in all directions. Its resolution is high enough that den-
tists can see the periodontal space of the adjacent tooth and even the
trabecular structure of the bone. With the segmentation function, it is
possible to select a specic anatomical structure for further processing.
For example, a tooth adjacent to the proposed implant can be selected
and virtually extracted or become half transparent in order for the den-
tist to have a better inspection of the proposed implant. Also, the vir-
tual abutment on the proposed implant can be positioned, and the
space between the virtual abutment and the opposite dentition esti-
mated. Once the implant position and orientation are nalised, the
surgical guide can be precisely fabricated using CNC milling or 3D
printing. According to the literature, the error of the tip of an implant
is 1mm on average, provided that a surgical guide was used during
surgery (Van Assche etal. 2012).
With the implant planning software, surgical guides can be fabricated
based on radiographic information of the patient to guide dentists for
more accurate implant placement. e surgical guide can be made in-
oce, by dental technicians, or even by companies that specialise in this
kind of services. In recent years, an implant surgery navigation system
based on optical tracking mechanism has become available in the market.
Compared to the implant surgery navigation system, the surgical guide
oers a much cheaper option with nearly the same functions. Although
CBCT is still a pricey instrument, the benets that it provides to implant
surgery make the return of investment the fastest compared to that of
other equipment of digital dentistry.
Digitalisation inDentistry: Development andPractices
212
8.7 Discussion: Impacts ofDigital Dentistry
onDentists andDental Technicians
8.7.1 Impacts ofDigital Dentistry onDentists
Every new technology evolved is a double-edged sword. e advantages
of the digital technology are that dentists are able to diagnose and treat
patients eciently, as described in the sections above. In this section, the
disadvantages associated with digital dentistry are explained in detail. e
rst thing is the learning curve. Most dentists never learned the principles
and the applications of digital dentistry when they were students. Some
clinicians are willing to try the new technology, but they do not have the
full understanding of how digital equipment works; therefore, bad expe-
riences may mislead them to the conclusion that digital technology is not
ready yet. In contrast, those early adopters who thoroughly understand
this technology consider it as an opportunity. For them, digital dentistry
is not just technology, but also a marketing strategy and a tool to save
chair time. ose early adopters also have the opportunity to dominate
the continuing education market for digital dentistry. Nowadays, patients
are well informed, and they would rather go to a dentist who is tech-savvy
than someone who is old fashioned.
e second disadvantage of the digital dentistry is the cost. At the time
of writing this article (2017), it is still dicult for dentists to aord all the
technologies available. Dentists could face negative nancial results if
they cannot estimate the benet and return of the digital technologies
and thus overinvest on them. It must be understood that every equip-
ment has its service life, after which it is not economical to keep the
equipment running. erefore, it is important to get value from the
equipment during the period of service life. For example, until recently,
the overall benets of digital impression were just above the level below
which it does not make sense for many dentists to purchase the equip-
ment. e “overall benet” here refers to the time saved, the acceptable
accuracy and a better workow compared to the conventional way of an
impression. In Taiwan, to start a dental practice with ve dental chairs
with a CBCT and other essential equipment (no CAD/CAM machines)
costs at least 400,000 US dollars. With CAD/CAM machines, the cost is
Y.-M. Lin
213
even higher. is total cost is beyond the range that a young dentist can
aord. erefore, large corporations are investing in more and more digi-
tal dental clinics in Taiwan.
In addition to the cost of the equipment, there is an extra cost that
dentists must know about. For example, if a dentist had so many cases
that he invested on a CNC milling machine in his practice, he must also
hire a dental technician for CAD and to operate the CNC milling
machine. In addition, a high-pressure air compressor, an air lter and
drying system, and a high-power vacuum machine are essential accesso-
ries to a CNC milling machine. Also, a high-temperature sintering fur-
nace is necessary if a dentist intends to fabricate a zirconium dioxide
restoration. In addition to the hardware cost, another hidden cost that is
sometimes underestimated is the annual licence fee or subscription fee.
For instance, 3 Shape charges an annual subscription fee for all of their
intraoral scanners, some of their desktop scanners, CAD software (all
modules) and orthodontic software. e subscription fee is 1500 euro for
either their DentalDesigner™ Premium software or D900 DentalSystem™
premium scanner.
As mentioned before, the open system digital impression/CAD/CAM
system has provided us with a cheaper solution for digital dentistry.
However, despite these savings, dentists may encounter the “compatibil-
ity issue” between dierent brands. is “compatibility issue” is caused
due to diering software design philosophies, the dierent data eld in
certain databases or even dierent nomenclatures to the same objects.
Luckily, this incompatibility can be solved during a software update.
However, before their newly established digital dentistry workow
becomes smooth enough for daily practices, dentists have to spend some
time to optimise the parameters for each equipment.
8.7.2 Impacts ofDigital Dentistry onDental
Technicians
Not only does digital dentistry aect dentists, it also aects dental techni-
cians and as a result inuences capital concentration. e barrier to
prevent the small capital from entering the automated production is the
Digitalisation inDentistry: Development andPractices
214
disadvantage of digital dentistry. Small dental labs, staed by four to ve
dental technicians or fewer, may not have the buying power to get the
equipment with the latest technology at a lower price as compared to a
large laboratory. erefore, these smaller laboratories could probably end
up closing their business due to the inability to compete in price. For
mid-size and larger labs, it will be easier to carry on with business. Despite
it being a huge nancial burden to continuously upgrade the equipment
and train technicians to update their knowledge, with the well-trained
technicians coupled with a smooth workow, it is possible to increase
production and keep costs competitive, which is the biggest advantage of
digital dentistry. Another way for a dental laboratory to maintain their
business and levels of the product quality is to be “bought out” by large
corporations. In Taiwan, because of the low gross prot margin of the
electronics industry, many electronics companies looked for new venture
opportunities, and it turned out that they entered the dental market by
the acquisition of a large dental laboratory.
With a attening world, it is easier to send the work of dental techni-
cians overseas, most commonly in China. ere are laboratories in China
which hire more than 4000 employees in the factory. For most dental
laboratories in the developed countries, the biggest expense is labour.
While oshoring can save quite a few labour expenses and get a lower
price in the dental prosthesis, good communication and quality of the
products and the materials that the oshore factory oers may not be
achieved easily. erefore, a domestic dental laboratory has to compete
with the oshore laboratory only by increasing the quality and enhancing
communications with the local dentists.
8.8 Conclusion andtheFuture ofDigital
Dentistry
Digital dentistry is still in its budding stage; therefore, many young den-
tists grab every opportunity to absorb the knowledge and experiences in
digital dentistry. In view of this trend, School of Dentistry, National
Yang-Ming University, oered the rst full-semester digital dentistry
course for undergraduate students in Taiwan. e course not only drew
Y.-M. Lin
215
the attention of the undergraduate students, there were also many senior
dentists who audited the course. It can be foreseen that the digital den-
tistry course will become a required subject for undergraduate dental
students.
ere are still many developing technologies, especially the dynamic
motion capture, articial intelligence (AI) and multicolour 3D printing,
which will further improve the dental workow. Using intraoral scanner
and CBCT, it is only possible to recreate the inter-maxillary relationship
in a static state. It means that during jaw movement, such as chewing, the
occlusal interference cannot be totally eliminated during CAD stage. A
jaw motion tracking device can record the jaw movements and detect
abnormality of the temporal mandibular joint. With the jaw motion
tracking device, the dynamic occlusal adjustment will be applied during
the CAD stage, and the removal of the dynamic occlusal interference can
avoid the tedious occlusal adjustment during the delivery of
restorations.
Automatic restoration design, automatic treatment plan making and
prediction of the border of the complete denture, can be some of the roles
that AI will play in dentistry. e restoration design and treatment plan
making are highly dependent on dentist’s experiences. For newly gradu-
ated dentists, help from AI can enormously reduce the complications of
a poorly made treatment plan. In order to obtain enough data from
patients, manufacturers of the intraoral scanners, such as 3 Shape and
3M, upload the scanned data to their server after completion of the scan-
ning. It is still unknown what kind of AI applications they are developing
now; however, more companies have seen the potential of the dental
database and collect them as much as possible.
Multicolour 3D printing is a potential technology in the dental labora-
tory. For an aesthetic restoration, the current digital way is milling a
ceramic block with the closest shade, followed by manual staining, tex-
turing and glazing by technicians. It is labour intensive, and restorations
made this way have characteristic colours coming from the surface instead
of coming from “inside”. With the multicolour 3D printing of ceramics,
this problem may be solved in the future. A technician can design the
colour of a restoration to simulate the colour of dentin and enamel, trans-
parency of mamelons and the surface texture of the teeth.
Digitalisation inDentistry: Development andPractices
216
Digital dentistry is not just hype. When properly implemented and
invested, digital technology will be benecial to dentists, dental techni-
cians and patients. Despite many clinicians still lacking condence in the
digital dentistry now, many third-party entities, such as dental laborato-
ries, image centres and continuing education institutes, can collaborate
with dentists for better clinical outcomes. As the technology advances,
the attened learning and lowered cost will lower the barrier for dental
community to enter the digital dentistry. is will happen very soon.
References
Andre, Jean-Claude. (1984). Disdpositif pour realiser un modele de piece indus-
trielle, (ed.) National De La Propriete Industrielle, France.
Cowburn, S., & Cowburn, G. (2016). Digital dentistry– Removing the barriers
to entry. Oral Health. https://www.oralhealthgroup.com/features/digital-
dentistry-removing-barriers-entry/
Duret, F. (1990). CAD/CAM and beyond: A interview with Dr. Francois Duret.
Interview by Dr. George Freedman. Dentistry Today, 9 (6), 31-3–37-8, 46.
Ender, A., & Mehl, A. (2011). Full arch scans: Conventional versus digital
impressions--an in-vitro study. International Journal of Computerized
Dentistry, 14 (1), 11–21.
Ender, A., Attin, T., & Mehl, A. (2016). In vivo precision of conventional and
digital methods of obtaining complete-arch dental impressions. e Journal
of Prosthetic Dentistry, 115 (3), 313–320. https://doi.org/10.1016/j.
prosdent.2015.09.011.
Hull, C.W. (1986). Apparatus for production of three-dimensional objects by
stereolithography. Google Patents.
McLean, J.W., & von Fraunhofer, J.A. (1971). e estimation of cement lm
thickness by an invivo technique. British Dental Journal, 131(3), 107–111.
Mormann, W.H. (2006). e evolution of the CEREC system. Journal of the
American Dental Association, 137 (Suppl), 7S–13S.
Obama, B. (2013). Remarks by the President in the state of the union address (ed.).
Oce of the Press Secretary.
Penate, L., Basilio, J., Roig, M., & Mercade, M. (2015). Comparative study of
interim materials for direct xed dental prostheses and their fabrication with
CAD/CAM technique. e Journal of Prosthetic Dentistry, 114 (2), 248–253.
https://doi.org/10.1016/j.prosdent.2014.12.023.
Y.-M. Lin
217
Van Assche, N., Vercruyssen, M., Coucke, W., Teughels, W., Jacobs, R., &
Quirynen, M. (2012). Accuracy of computer-aided implant placement.
Clinical Oral Implants Research, 23(Suppl 6), 112–123. https://doi.
org/10.1111/j.1600-0501.2012.02552.x.
Weisberg, D.E. (2008). e engineering design revolution. http://www.cadhis-
tory.net/
Yao, J., Li, J., Wang, Y., & Huang, H. (2014). Comparison of the exural
strength and marginal accuracy of traditional and CAD/CAM interim mate-
rials before and after thermal cycling. e Journal of Prosthetic Dentistry,
112(3), 649–657. https://doi.org/10.1016/j.prosdent.2014.01.012.
Digitalisation inDentistry: Development andPractices
