Biosci. Biotech. Res. Comm. 10(4): 790-796 (2017)
Dimentional accuracy of intraoral and laboratory
scanners: A literature review
Iman Sha ei
, Mehran Bahrami
and Saied Nokar
Prosthetic Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
Assistant Professor, Dental Research Center, Department of Prosthodontics, School of Dentistry, Tehran
University of Medical Sciences, North Amirabad Ave, Tehran, Iran
Associate Professor, Department of Prosthodontics, Dental Research Center, Tehran University of Medical
Sciences, Tehran, Iran
Restoration of dental implants remains one of the most challenging aspects of implant dentistry. Although it is
not clear whether prosthetic mis t could affect osseointegration, mechanical complications of implant-supported
prostheses can be avoided by achieving a good passive  t between the framework and the implants. Passive  t is a
dif cult concept to de ne. Obtaining absolute passive  t of the prosthetic framework on implants has been reported
to be nearly impossible. Dimentional accuracy of intraoral and laboratory scanners play deniable role on producing
desirable restorations. So, the aim of the current research was to determine dimentional accuracy of intraoral and
laboratory scanners using the PubMed and Medline database English literature by the terms “Dimentional accuracy”,
“Intraoral”, Laboratory scanners”.
*Corresponding Author:
Received 30
Sep, 2017
Accepted after revision 1
Dec, 2017
BBRC Print ISSN: 0974-6455
Online ISSN: 2321-4007 CODEN: USA BBRCBA
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© A Society of Science and Nature Publication, 2017. All rights
Online Contents Available at:
DOI: 10.21786/bbrc/10.4/26
Technique of computer aided design and computer aided
manufacturing (CAD/CAM) is used to produce ceramic
restorations such as all-ceramic crowns and  xed dental
prostheses since decades ago (Su et al. 2015). Numer-
ous CAD/CAM systems are capable of designing and
fabricating prostheses on plaster cast made from con-
ventional silicone impressions (Mo¨rmann, 2006). Non-
standard operation during impression taking and defor-
mation of clinical material will affect the accuracy of
plaster model, consequently affecting the accuracy of
three-dimensionalmodels (3D) model data and prosthe-
ses quality (Stimmelmayr et al. 2012). So, it is desirable
Iman Sha ei et al.
to develop a facility which can take digital impressions
directly from oral cavity to eliminate error and also
economize on impression materials used in conventional
impression procedures. The primery digital intraoral
impression system commercially available was CEREC 1
system (Rekow, 2006). Laboratory digitizing starts with
a conventional impression that is poured, and the leads
model is digitized, using one of numerous optical or
mechanical systems (Beuer et al. 2004). Also, some sys-
tems offer the possibility to scan the impression directly
without cast fabrication (Güth et al. 2013).
In addition, discomfort for the patient like sweat-
ing, gagging, pain and partially inconvenient taste is
a known issue associated with conventional impression
taking. In these situations, this instability and discom-
fort factor might be avoided by direct data capturing,
which represents a logical direct access to dental CAD/
CAM (Steinhäuser-Andresen et al. 2011). To date few
published literature exists on the performance of digital
intraoral impression system, especially concerning the
accuracy and precision of intraoral scanners. So, the aim
of the current research was to determine dimentional
accuracy of intraoral and laboratory scanners.
The keywords used for the literature search for this
review was peer-reviewed articles following key-words:
Dimentional accuracy × Intraoral scanners and Labo-
ratory scanners. Among them, the papers were  t the
criteria selected and available full-text articles read.
Related articles were also scrutinized. Hand search was
also driven. The search was carried out using Biological
Abstracts, Chemical Abstracts, and the data bank of the
PubMed and Medline database updated to 2017. The ref-
erences found in the search were then studied in detail.
To achieve a correct adaptation between the prosthe-
sis and the implants, the  rst step is to obtain a highly
accurate impression. Many clinical factors affect the
accuracy of the impressions, such as tray type, impres-
sion technique, impression material used and its particu-
lar hydrophobic or hydrophilic characteristics, mixing
methods and impression disinfection. Impressions can
be made at either the implant level or the abutment level
(Giménez et al. 2015). Computer-aided design/computer
aided manufacturing (CAD/CAM) systems have evolved
over the last two decades and have been used by dental
health professionals for over twenty years (Duret et al.
1998). Francois Duret introduced CAD/CAM in restora-
tive dentistry (Priest, 2005). One of the main lines of
implementation was the intraoperative use for dental
restoration using prefabricated ceramic monoblocks
(Mörmann, 2004). Dental CAD/CAM’s evolution over
the past30 years has centered on the chairside market,
beginning with CEREC® (Sirona). This is in part because
the appeal of the CAD/CAM concept is that it offers
dental professionals and their patients the convenience
of same-day dentistry (Davidowitz and Kotick, 2011).
A further development in CAD/CAM technology is the
transition from closed  le format to open access  le
systems, which opens up access to a much wider range
of manufacturing technology such that the most appro-
priate manufacturing processes and associated materials
can be selected (van Noort, 2012).
The CAD/CAM systems have been used mostly for
the manufacturing of prosthetic  xed restorations, such
as inlays, onlays, veneers and crowns. During the last
decade technological developments in these systems
have provided alternative restorations using differ-
ent materials such as porcelain, composite resin and
metallic blocks, which could not be prosecuted previ-
ously because of technical limitations. To date several
optical impression systems have been developed with
which direct impressions could be made in the oral cav-
ity including Cerec AC (Sirona, Behnheim), Lava Chair-
side Oral Scanner (Lava COS, 3 M ESPE), E4D Dentist
(D4D Technologies, LLC) and iTero (Cadent, Carlstadt)
(Giménez et al. 2015). Despite numerous advantages
introduced for dental implants, several challenges, since
excellent accuracy is a prerequisite to achieve proper  t
of the subsequent prosthesis (Giménez et al. 2014). There
is scarce information on the accuracy of intraoral digi-
tal impression systems for dental implants including the
implant-related factors and other clinical aspects such as
the experience of the operator.
For the acquisition of digital images of teeth, different
procedures have been described: digitization of plaster
casts, digitization of impressions, and intraoral digi-
tal impressions (Morris et al. 2010). Digital work  ow
has been proposed to improve treatment planning, give
higher ef ciency, and allow new methods of produc-
tion and new treatment concepts (Galovska et al. 2012).
Data storage and reproducibility are facilitated, and
treatment documentation and communication between
professionals as well as between dentists and patients
have become more convenient (Al Mortadi et al. 2012).
Currently, there are a major digital impression devices:
iTero (Align Technologies, San Jose, Calif), Lava COS
(3M ESPE, Seefeld, Germany), and Trios (3Shape, Copen-
hagen, Denmark) for image acquisition; and CEREC AC
(Sirona, Bensheim, Germany) and E4D (D4D Technolo-
gies, Richardson, Tex) for digital imaging and in-of ce
manufacturing (Flugge et al. 2013). All scanning devices
Iman Sha ei et al.
need drying and powdering of intraoral surfaces (CEREC,
E4D, Lava COS). Also, digital impressions are acquired
without contact to the gingival tissues (Ender and Mehl,
2011). Direct acquisitions systems have been constantly
improved because this are less invasive, quicker and
more precise than the conventional methods. Besides the
digital image can be easily store for a long time (Ramsey
and Ritter, 2012).
Lost-wax is the traditional technique for fabricating the
metal substructure is the lost-wax technique and using
various metal alloys for casting (Ucar et al. 2009). Con-
ventionally, wax patterns were fabricated with wax and
waxing instruments for example the popular PKT instru-
ments. Wax is used to make the patterns because it can
be conveniently manipulated, precisely shaped and can
also be completely eliminated from the mold by heat-
ing. The fabrication of the wax pattern is the most criti-
cal and labor-intensive step in making the porcelain
fused-metal crown (Vojdani et al. 2013). To fabricate a
restoration prepared using the lost-wax technique, the
dentist must  rst make an impression and the impres-
sion appointment may be uncomfortable for the patient
because of the retraction procedure and need for anes-
thesia. Subsequently, time is required by the dental labo-
ratory technician for careful pouring of the stone die or
cast from the impression, preparation of the cast, then
fabrication of the wax pattern, investing, and casting.
Considering the lower unit cost of base metal alloys, a
more economical dental laboratory technique would be
helpful to replace the previously described technique for
preparing cast restorations (Ucar et al. 2009).
Selective laser sintering (SLS) is a manufacturing tech-
nology recently introduced in dentistry. SLS, is one of
the fast prototyping production techniques, uses a high-
temperature laser to beam selectively substructure metal
powder based on the CAD data with the  xed dental pros-
theses design. A thin layer of the beamed area becomes
burnt and the  xed dental prostheses is completed by
laminating these thin layers. The metal-ceramic crown is
formerly one of the most commonly used  xed dental
prostheses and the lower core is mostly produced by the
lost wax technique and casting method. However, SLS
system has several bene ts such as material, time and
expenses saving was well as the production is simpler
compared to the existing methods (Akova et al. 2008).
With CEREC 1 and CEREC 2, an opticalscan of the pre-
pared tooth is made with a couple charged device (CCD)
camera, and a 3-dimensional digital image is generated
on the monitor. The restoration is then designed and
milled. With the newer CEREC 3D, the operator records
multiple images within seconds, enabling clinicians to
prepare multiple teeth in the same quadrant and create
a virtual cast for the entire quadrant. The restoration is
then designed and transmitted to a remote milling unit
for fabrication. While the system is milling the  rst res-
toration, the software can virtually seat the restoration
back into the virtual cast to provide the adjacent con-
tact while designing the next restoration (Estafan et al.
DCS Precident
The DCS Precident system is comprised of a Preciscan
laser scanner and Precimill CAM multitool milling center.
The DCS Dentform software automatically suggests con-
nector sizes and pontic forms for bridges. It can scan 14
dies simultaneously and mill up to 30 framework units
in 1 fully automated operation. Materials used with DCS
include porcelain, glass ceramic, In- Ceram, dense zir-
conia, metals, and  ber- reinforced composites. This
system is one of the few CAD/CAM systems that can
mill titanium and fully dense sintered zirconia (Sjogren
et al. 2004).
Procera/AllCeram was introduced in 1994 and according
to company data, has produced 3 million units as of May
2004. Procera uses an innovative concept for generating
its alumina and zirconia copings. First, a scanning stylus
acquires 3D images of the master dies that are sent to
the processing center via modem. The processing center
then generates enlarged dies designed to compensate
for the shrinkage of the ceramic material. Copings are
manufactured by dry pressing high-purity alumina pow-
der (>99.9%) against the enlarged dies. These densely
packed copings are then milled to the desired thickness.
Subsequent sintering at 2,000°C imparts maximum den-
sity and strength to the milled copings. The complete
procedure for Procera coping fabrication is very tech-
nique-sensitive because the degree of die enlargement
must precisely match the shrinkage produced by sinter-
ing the alumina or zirconia (Posselt et al. 2003).
Lava introduced in 2002, Lava uses a laser optical sys-
tem to digitize information from multiple abutment
margins and the edentulous ridge. The Lava CAD soft-
ware automatically  nds the margin and suggests a
pontic. The framework is designed to be 20% larger to
compensate for sintering shrinkage. After the design is
complete, a properly sized semisintered zirconia block
is selected for milling. The block is bar coded to register
the special design of the block. The computer- controlled
Iman Sha ei et al.
precision milling unit can mill out 21 copings or bridge
frameworks without supervision or manual intervention.
Milled frameworks then undergo sintering to attain their
nal dimensions, density, and strength. The system also
has 8 different shades to color the framework for maxi-
mum esthetics (Bindl et al. 2004).
Marketed in 2002, the Everest system consists of scan,
engine, and therm components. In the scanning unit, a
re ection-free gypsum cast is  xed to the turntable and
scanned by a CCD camera in a 1:1 ratio with an accu-
racy of measurement of 20 m. A digital 3D model is
generated by computing 15 point photographs. The res-
toration is then designed on the virtual 3D model with
Windows-based software. Its machining unit has 5-axis
movement that is capable of producing detailed mor-
phology and precise margins from a variety of materi-
als including leucite-reinforced glass ceramics, partially
and fully sintered zirconia, and titanium. Partially sin-
tered zirconia frameworks require additional heat pro-
cessing in its furnace (Blatz et al. 2003).
The Cercon System is commonly referred to as a CAM
system because it does not have a CAD component. In
this system, a wax pattern (coping and pontic) with a
minimum thickness of 0.4 mm is made. The system scans
the wax pattern and mills a zirconia bridge coping from
presintered zirconia blanks. The coping is then sintered
in the Cercon heat furnace (1,350°C) for 6 to 8 hours.
A low-fusing, leucite-free Cercon Ceram S veneering
porcelain is used to provide the esthetic contour. In an
in vitro study the marginal adaptation for Cercon all-
ceramic crowns and  xed partial dentures was reported
as 31.3 m and 29.3 m, respectively (Ariko et al. 2003).
Several intraoral scanners have been introduced in the
recent decades, and an increasing number of dental clin-
ics have decided to adopt these powerful devices for cap-
turing digital impressions (Mangano et al. 2016). Cap-
turing of digital impressions of the dental arches using
this system can done by only a light beam, without the
need of individual trays and materials (alginate, silicone,
polyether) that are traditionally used to take impressions
(Logozzo et al. 2014). Because of the unpleasant proce-
dure, especially for those with a pronounced gag re ex
conventional impressions are generally not appreciated
by patients (Zimmermann et al. 2015). The possibility to
effectively replace conventional impressions is the main
advantage of intraoral digital impressions, which leads
to decrease materials costs (Yuzbasioglu et al. 2014).
Immediate control of the quality of the impression, and
the possibility of obtaining 3D which can be electroni-
cally sent to the laboratory is known as advantages for
this system (Schepke et al. 2015).
Digital impression making has improved this pro-
cess and the ability to evaluate the preparation in real-
rime. Having the capability of acquiring a scan of a
prepared tooth and visualizing it on a computer moni-
tor eliminates the issues associated with conventional
impressions. The dentist is now able to see a magni ed
high-resolution image of exactly what is present in the
oral cavity and not just a negative representation. This
improved visualization enables the dentist to see and
evaluate, in exquisite detail, the quality of the prepa-
rations, while the patient is still in the chair. Factors
such as preparation taper, quality of margins, undercuts,
inter-occlusal clearance, and path of draw can be color-
coded displayed and directly corrected if necessary, and
a new digital impression can be made within seconds.
All of the currently available conventional impression
materials exhibit some degree of dimensional change
that builds distortion and inaccuracy into the  nal res-
toration. Digital impressions can reduce the possibility
of dimensional change (shrinkage) that is evident with
all conventional impression materials. Voids, tears, and
pulls that are routinely experienced with conventional
materials are no longer an issue with digital scans (Geb-
hards et al. 2010).
Laboratory digitizing starts with a conventional
impression that is poured, and the resulting model is
digitized, by using one of several optical or mechanical
systems (Beuer et al. 2008). As well, some systems offer
the possibility to scan the impression directly without
cast fabrication (Quaas et al. 2007). However, in either
instance, the initial step of the highly precise digi-
tal work ow is an analogue impression. Conventional
high precision impression materials, like hydrocolloid,
polyether, polyvinyl or polysul de in combination with
stone casts, offer a well-known procedure to transfer
the clinical situation into the laboratory. However, some
drawbacks are related to the sensitive process steps of
this technique (Haim et al. 2009).
The CAD-CAM system includes three parts, which
correspond to the three basic steps of the process: (I)
First, a device is used to input the existing dental shapes
into the system. This device includes a laser source
(diode) which, through the  rst endoscope, projects light
on the desired picture area. A second endoscope, adja-
cent to the  rst, allows a camera to take pictures in the
mouth. This camera is connected to a system that digi-
tizes the information and correlates the different views
(Duret et al. 1985). (II) The CAD system, including all
necessary hardware and software, allows the operator
to create an electronic model of the impression, display
Iman Sha ei et al.
it on the screen, an d use it to design the prosthesis.
The CAD system is linked to a proprietary articulator,
called the Access Articulator, which provides the data
relating to the dynamic movements of the jaw. (III) The
CAM system, which includes a numerically controlled
machine tool with four-axis capability. This machine
will automatically mill the prosthesis from conventional
or special materials (Belser et al. 1985).
Comparison of the accuracy of direct and indirect
To date numerous researches have been done on com-
parison of the accuracy of direct and indirect dental
scanners. However, proces and cones reported for each
system, here we highlighted the most signi csnt nd-
ings of the previous reports. For the precision of direct
digital impression, Guth et al. (2013) compared the 3D
average and standard deviations of intraoral digital
impression (Lava Chairside Oral Scanner) with those
of extraoral desktop scanner (Lava Scan ST laboratory
scanner) in an in-vitro study where a molar and premo-
lar were scanned. It revealed the 3D standard deviations
of 19 µm for the intraoral digital scanner and 31 µm for
the extraoral scanner. Ender and Mehl (2011) compared
the trueness and precision of digital impressions of the
full arch with those of conventional impressions using
a reference scanner on a in-vitro model, and the results
showed that precision was 61.3 ± 17.9 µm for conven-
tional impression, 30.9 ± 7.1 µm for digital impression
with the Cerec Bluecam and 60.1±31.3 µm for digital
impression with Lava C.O.S.
Guth et al. (2013) found that digital impressions made
using Lava C.O.S. were more accurate than a laboratory
scan of a conventional impression and conversion to a
digital  le. Mangano et al. (2016) in research on trueness
and precision of four intraoral scanners in oral implan-
tology revealed in the partially edentulous maxilla, CS
3500 had the best general trueness (47.8 m) and pre-
cision (40.8 m), followed by Trios (trueness 71.2 m,
precision 51.0 m), Zfx Intrascan (trueness 117.0 m,
precision 126.2 m), and Planscan (trueness 233.4 m,
precision219.8 m). With regard to general trueness,
Trios was signi cantly better than Planscan, CS 3500
was signi cantly better than Zfx Intrascan and Planscan
and Zfx Intrascan was signi cantly better than Plans-
can; with regard to general precision, Trios was signi -
cantly better than Zfx Intrascan and Planscan, CS 3500
was signi cantly better than Zfx Intrascan and Planscan
and Zfx Intrascan was signi cantly better than Planscan.
In the totally edentulous maxilla, CS 3500 had the best
performance in terms of general trueness (63.2 m) and
precision (55.2 m), followed by Trios (trueness71.6 m,
precision 67.0 m), Zfx Intrascan (trueness 103.0 m,
precision112.4 m), and Planscan (trueness 253.4 m,
precision 204.2 m). With regard to general trueness,
Trios was signi cantly better than Planscan, CS 3500
was signi cantly better than Zfx Intrascan and Planscan
and Zfx Intrascan was signi cantly better than Planscan
with regard to general precision, Trios was signi cantly
better than Zfx Intrascan and Planscan, CS 3500 was
signi cantly better than Zfx Intrascan and Planscan and
Zfx Intrascan was signi cantly better than Planscan.
Local trueness values con rmed these results (Mangano
et al. 2016).
On Precision of intraoral digital dental impressions
with iTero and extraoral digitization with the iTero and
a model scanner Flugge et al. (2013) reported scanning
with the iTero is less accurate than scanning with the
D250. Intraoral scanning with the iTero is less accurate
than model scanning with the iTero, suggesting that
the intraoral conditions (saliva, limited spacing) con-
tribute to the inaccuracy of a scan. For treatment plan-
ning and manufacturing of tooth-supported appliances,
virtual models created with the iTero can be used. An
extended scanning protocol could improve the scanning
results in some regions. In a study on accuracy 3M Lava
C.O.S., 3Shape D900, Cadent iTero, CEREC Bluecam, and
E4D Dentistdigital impression systems revealed digital
impressions from the Cadent iTero system were the most
accurate (Ali, 2015).
Recently, on comparison of repeatability between
intraoral digital scanner and extraoral digital scan-
ner, Su et al. (2015) revealed precision decreases with
the increased scanning scope. Precision was clinically
acceptable when scanning scope was less than half arch.
Precision of extraoral scanning was acceptable in scan-
ning any scope of arch region. Güth et al. (2013) revealed
the direct digitalisation with Lava C.O.S. showed statisti-
cally signi cantly higher accuracy compared to the con-
ventional procedure of impression taking and indirect
Akova T, Ucar Y, Tukay A, Balkaya MC, Brantley WA. 2008
Comparison of the bond strength of laser-sintered and
cast base metal dental alloys to porcelain. Dent Mater 24:
Al Mortadi N, Eggbeer D, Lewis J, Williams RJ. 2012 CAD/
CAM/AM applications in the manufacture of dental appli-
ances. Am J Orthod Dentofacial Orthop 2012;142:727-33.
Ali AO (2015) Accuracy of Digital Impressions Achieved from
Five Different Digital Impression Systems. Dentistry 5: 300.
Ariko K. 2003 Evaluation of the marginal  tness of tetragonal
zirconia polycrystal all-ceramic restorations. Kokubyo Gakkai
Zasshi. 2003;70:114-123. Japanese.
Belser UC, MacEntee M.I, Richter WA. 1985 Fit of three porce-
lain-fused-to-metal marginal designs in vivo: and a scanning
electron microscope study. J Prosthet Dent (53):24-34
Iman Sha ei et al.
Beuer F, Schweiger J, Edelhoff D (2008) Digital dentistry: an
overview of recent developments for CAD/CAM generated res-
torations. Br Dent J 204:505–511
Beuer F, Schweiger J, Edelhoff D (2008) Digital dentistry: an
overview of recent developments for CAD/CAM generated res-
torations. Br Dent J 204:505–511
Bindl A, Mormann WH. 2004 Survival rate of mono-ceramic
and ceramic-core CAD/CAM generated anterior crowns over
2-5 years. Eur J Oral Sci.2004;112:197-204.
Blatz MB, Sadan A, Blatz U. 2003 The effect of silica coating
on the resin bond to the intaglio surface of Procera AllCeram
restorations. Quintessence Int. 2003;34:542-547.
Davidowitz, G. & Kotick, P.G. (2011) The use of CAD/CAM in
Dentistry. Dental Clinics of North America, 55(3), 559–570.
Duret F, Blouin JL, Duret B. CAD-CAM in dentistry. J Am Dent
Assoc. 1988;117:715-20.
Duret, F.: Duret, B.; el Blouin, J.L. 1985 Bases fondamentales
dans la conception et fabrication assistées par ordinateur des
prostheses dentaires. QOS 39:197-215
Ender A, Mehl A. 2011 Full arch scans: conventional versus
digital impressions—an in-vitro study. Int J Comput Dent
Estafan D, Dussetschleger F, Agosta C 2003 Scanning electron
microscope evaluation of CEREC II and CEREC III inlays. Gen
Dent. 51:450-454.
Flugge TV, Schlager S, Nelson K, Nahles S, Metzger MC. 2013
Precision of intraoral digital dental impressions with iTero and
extraoral digitization with the iTero and a model scanner. Am
J Orthod Dentofacial Orthop 144:471-8
Galovska M, Petz M, Tutsch R. 2012 Unsicherheit bei der
datenfusion dimensioneller messungen. tm-Technisches Mes-
sen 79: 238-45.
Gebhards, A., Schmidt, F.M., & Hotter, J.S. (2010) Additive
Manufacturing by selective laser melting the realizer desktop
machine and its application for the dental industry. Physics
Procedia, 5, 543–549.
Giménez B, Pradíes G, Martínez-Rus F, Özcan M. 2015 Accu-
racy of two digital implant impression systems based on con-
focal microscopy with variations in customized software and
clinical parameters. Int J Oral Maxillofac Implants 30:56–64.
Giménez Be, Özcan M, MR Francisco, Pradíes G. 2014 Accu-
racy of a digital impression system based on parallel confocal
laser technology for implants with consideration of operator
experience and implant angulation and depth. Int J Oral Max-
illofac Implants 29:853–862.
Gu th J-F, Keul C, Stimmelmayr M, Beuer F, Edelhoff D. 2013
Accuracy of digital models obtained by direct and indirect data
capturing. Clin Oral Investig 17:1201–8.
Güth FJ, Keul C, Stimmelmayr M, Beuer F, Edelhoff D. 2013
Accuracy of digital models obtained by direct and indirect data
capturing. Clin Oral Invest 17:1201–1208.
Haim M, Luthardt RG, Rudolph H, Koch R, Walter MH, Quaas
S(2009) Randomized controlled clinical study on the accuracy
of two-stage putty-and-wash impression materials. Int J Pros-
thodont 22:296–302.
Logozzo S, Zanetti EM, Franceschini G, Kilpela A, Makynen
A. 2014 Recent advances in dental opticsÐ Part I: 3D intraoral
scanners for restorative dentistry. Optics Lasers Eng 54 (3):
Mangano FG, Veronesi G, Hauschild U, Mijiritsky E, Mangano
C (2016) Trueness and Precision of Four Intraoral Scanners in
Oral Implantology: A Comparative in Vitro Study. PLoS ONE
11(9): e0163107.
Mo¨rmann WH. The evolution of the CEREC system. J Am Dent
Assoc 2006 ;137(September (Suppl)):7S–13S.
Mörmann WH. 2004 The origin of the Cerec method: a per-
sonal review of the  rst 5 years. Int J Comput Dent. 7:11-24.
Morris JB. 2010 CAD/CAM options in dental implant treatment
planning. J Calif Dent Assoc :333-6.
Posselt A, Kerschbaum T. 2003 Longevity of 2,328 chairside
Cerec inlays and onlays. Intl J Comput Dent. 6:231-248.
Priest G. 2005 Virtual-designed and computer-milled implant
abutments. J Oral Maxillofac Surg. 63:22-32.
Quaas S, Rudolph H, Luthardt RG (2007) Direct mechanical
data acquisition of dental impressions for the manufacturing
of CAD/ CAM restorations. J Dent 35:903–908
Ramsey CD, Ritter RG. 2012 Utilization of digital technologies
for fabrication of de nitive implant-supported restorations. J
Esthet Restor Dent. 24(5):299-308.
Rekow ED. 2006 Dental CAD/CAM systems: a 20-year success
story. J Am Dent Assoc 137(Suppl):5S–6S.
Schepke U, Meijer HJ, Kerdijk W, Cune MS. 2015 Digital ver-
sus analog complete-arch impressions for single- unit premo-
lar implant crowns: Operating time and patient preference. J
Prosthet Dent 114(3): 403±406 e1.
Sjogren G, Molin M, van Kijken JW. 2004 A 10-year prospec-
tive evaluation of CAD/CAM-manufactured (Cerec) ceramic
inlays cemented with a chemically cured or dual-cured resin
composite. Int J Prosthodont. 17:241-246.
Steinhäuser-Andresen S, Detterbeck A, Funk C, Krumm M,
Kasperl S, Holst A, Hirschfelder U (2011) Pilot study on accu-
racy and dimensional stability of impression materials using
industrial CT technology. J Orofac Orthop 72:111–124
Stimmelmayr M, Gu¨ th JF, Erdelt K, Edelhoff D, Beuer F. 2012
Digital evaluation of the reproducibility of implant scanbody
t—an in vitro study. Clin Oral Investig 16:851–6.
Su T-, Sun J. 2015 Comparison of repeatability between
intraoral digital scanner and extraoral digital scanner:
An invitro study. J Prosthodont Res (2015), http://dx.doi.
Ucar Y, Akova T, Akyil MS, Brantley WA. 2009 Internal  t
evaluation of crowns prepared using a new dental crown fabri-
cation technique: Laser-sintered Co-Cr crowns. J Prosthet Dent
Van Noort, R. (2012) The future of dental devices is digital.
Dental Materials, 28(1), 3–12.
Iman Sha ei et al.
Vojdani M, Torabi K, Farjood E, Khaledi AAR. 2013 Compari-
son the marginal and internal  t of metal copings cast from
wax patterns fabricated by CAD/CAM and conventional wax up
techniques. J Dent Shiraz Univ Med Sci, Sept. 14(3): 118-129.
Yuzbasioglu E, Kurt H, Turunc R, Bilir H. 2014 Comparison
of digital and conventional impression techniques: evaluation
of patients’ perception, treatment comfort, effectiveness and
clinical outcomes. BMC Oral Health, 14 (10): 7 pages.
Zimmermann M, Mehl A, Mormann WH, Reich S. 2015
Intraoral scanning systemsÐa current overview. Int J Comput
Dent 18 (2): 101-129.