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`A Comparative Analysis of Intraoral 3d Digital Scanners for Restorative
`Dentistry
`
`Research Gate
`
`Article · January 2011
`
`DOI: 10.5580/1b90
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`Exhibit 1006 page 1 of 19
`DENTAL IMAGING
`
`

`

`ISPUB.COM
`
`The Internet Journal of Medical Technology
`Volume 5 Number 1
`
`A Comparative Analysis Of Intraoral 3d Digital Scanners
`For Restorative Dentistry
`S Logozzo, G Franceschini, A Kilpelä, M Caponi, L Governi, L Blois
`
`Citation
`
`S Logozzo, G Franceschini, A Kilpelä, M Caponi, L Governi, L Blois. A Comparative Analysis Of Intraoral 3d Digital
`Scanners For Restorative Dentistry. The Internet Journal of Medical Technology. 2008 Volume 5 Number 1.
`
`Abstract
`
`Today, intra-oral mapping technology is one of the most exciting new areas in dentistry since three-dimensional scanning of the
`mouth is required in a large number of procedures in dentistry such as restorative dentistry and orthodontics. Nowadays, ten
`intra-oral scanning devices for restorative dentistry have been developed all over the world. Only some of those devices are
`currently available on the market; the others are still passing the clinical testing stages. All the existing intraoral scanners try to
`face with problems and disadvantages of traditional impression fabrication process and are driven by several non-contact optical
`technologies and principles. The aim of the present publication is to provide an extensive review of the existing intraoral
`scanners for restorative dentistry with particular attention to the evaluation of working principles, features and performances.
`
`INTRODUCTION
`The introduction of CAD/CAM concepts into dental
`applications was the brainchild of Dr. Francois Duret in his
`thesis presented at the Université Claude Bernard, Faculté
`d’Odontologie, in Lyon, France in 1973, entitled “Empreinte
`Optique” (Optical Impression). In detail he developed and
`patented a CAD/CAM device in 1984. The developed
`system was presented at the Chicago Midwinter Meeting in
`1989 by fabricating a dental crown in 4 hours (1, 2). Digital
`impressions have been introduced, and successfully used, for
`a number of years in orthodontics, as well, including
`Cadent’s IOC/OrthoCad, DENTSPLY/GAC’s OrthoPlex,
`Stratos/Orametrix’s SureSmile, and EMS’RapidForm but the
`introduction of the first digital intraoral scanner for
`restorative dentistry was in the 1980s by a Swiss dentist, Dr.
`Werner Mörmann, and an Italian electrical engineer, Marco
`Brandestini, that developed the concept for what was to be
`introduced in 1987 CEREC® by Sirona Dental Systems
`LLC (Charlotte, NC) as the first commercially CAD/CAM
`system for dental restorations (1, 3). Ever since research and
`development sectors at a lot of companies have improved the
`technologies and created in-office intraoral scanners that are
`increasingly user-friendly and produce precisely fitting
`dental restorations. These systems are capable of capturing
`three-dimensional virtual images of tooth preparations; from
`such images restorations may be directly fabricated (using
`CAD/CAM systems) or can be used to create accurate
`master models for the restorations in a dental laboratory (1).
`
`Nowadays, ten intra-oral scanning devices for restorative
`dentistry are available all over the world: four of them are
`made in USA, two in Israel, two in Germany and one in
`Italy, in Switzerland and in Denmark. Generally speaking
`such scanners try to face with problems and disadvantages of
`traditional impression fabrication process such as, in
`particular, mould instability, plaster pouring, laceration on
`margins, geometrical and dimensional discrepancy between
`the die and the mould. The main advantages in the
`employment of those devices are: high fidelity models,
`creation of 3D archives and surgery simulation and a process
`simplification. Existing devices are driven by several non-
`contact optical technologies such as confocal microscopy,
`optical coherence tomography, photogrammetry, active and
`passive stereovision and triangulation, interferometry and
`phase shift principles. Basically, all these devices combine
`some of the cited imaging techniques to minimize the noise
`source related to the scanning inside an oral cavity as, for
`example: optical features of the target surfaces (translucency
`and the different reflectivity of the target materials as teeth,
`gums, preparations, resins, etc.), wetness and random
`relative motions. Also several typologies of structured light
`sources and optical components are employed. The ten
`existing intra-oral scanning devices for restorative dentistry
`are listed below:
`
`1.
`
`CEREC® – by Sirona Dental System GMBH (DE)
`
`2.
`
`iTero – by CADENT LTD (IL)
`
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`A Comparative Analysis Of Intraoral 3d Digital Scanners For Restorative Dentistry
`
`3.
`
`E4D – by D4D TECHNOLOGIES, LLC (US)
`
`Figure 1
`
`4.
`
`Lava™C.O.S. – by 3M ESPE (US)
`
`5.
`
`IOS FastScan – by IOS TECHNOLOGIES, INC.
`(US)
`
`6.
`
`DENSYS 3D – by DENSYS LTD. (IL)
`
`7.
`
`8.
`
`DPI-3D – by DIMENSIONAL PHOTONICS
`INTERNATIONAL, INC. (US)
`
`3D Progress – by MHT S.p.A. (IT) and MHT
`Optic Research AG (CH)
`
`9.
`
`directScan – by HINT - ELS GMBH (DE)
`
`10.
`
`trios – by 3SHAPE A/S (DK)
`
`Only some of these are already commercially available. As
`already mentioned, even if a lot of advantages in taking
`digital impressions are attainable, there subsist also some
`disadvantages related to the existing devices. For example it
`is often necessary to apply some coatings on the teeth to
`minimize the noise of the measurement and to rest the
`camera wand on a tooth to get a steady focus. Moreover, the
`3D virtual model is often reconstructed by post-processing
`single images (acquired from a single perspective);
`accordingly the reconstruction is not performed in real time
`with a continuous data capture. Furthermore, data about the
`accuracy of the available instruments is missing. The aim of
`the present publication is the evaluation of all these existing
`devices with particular attention to the working principles
`they are based on, their features and performances.
`
`STATE OF THE ART AND COMPARATIVE
`ANALYSIS OF THE TECHNOLOGICAL
`ALTERNATIVES
`CEREC® BY SIRONA DENTAL SYSTEM GMBH
`(DE)
`CEREC® (an acronym for Chairside Economical
`Restoration of Esthetic Ceramics) was introduced by Sirona
`Dental System GMBH (DE) in 1987, and it has undergone a
`series of technological improvements, culminating in the
`CEREC AC® powered by BlueCam®, launched in January
`2009.
`
`
`
`2 of 18
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`DENTAL IMAGING
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`

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`A Comparative Analysis Of Intraoral 3d Digital Scanners For Restorative Dentistry
`
`
`
`Figure 2
`
`Figure 4
`Figure 4 - The CEREC AC BlueCam shorter wavelength
`blue light source (26)
`
`
`
`Figure 5
`Figure 5 – CEREC scanning system (6)
`
`The latest versions of the CEREC® system (see Figure 1 and
`2) are capable of producing inlays, onlays, crowns, laminate
`veneers, and even bridges and combine a 3D digital scanner
`with a milling unit (view Figure 3) to create in-office dental
`restorations from commercially available blocks of ceramic
`or composite material in a single appointment (1).
`
`The latest version of the milling centre, CEREC inLab® MC
`XL (see Figure 3), is capable of milling a crown in as little
`as 4 minutes. CEREC® systems may be described as
`measurement devices that operate according to the basic
`principles of confocal microscopy (3, 4) and according to the
`active triangulation technique (3, 5 and 6). A camera
`projects a changing pattern of blue light onto the object (see
`Figure 4) using projection grids that have a transmittance
`random distribution and which are formed by sub regions
`containing transparent and opaque structures (7). Moreover,
`by means of elements for varying the length of the optical
`path it is possible, for each acquired profile, to state specific
`relationship between the characteristic of the light and the
`optical distance of the image plane from the imaging optics
`(3, 4). A light source 3 (see figure 5) produces an
`illumination beam 7.1, 7.2, 7.3, that is focused onto the
`surface of the target object 2. An image sensor 6 receives the
`observation beam 9.1, 9.2, 9.3 reflected by the surface of the
`
`
`
`Figure 3
`Figure 3 - The in-office milling unit (25)
`
`
`
`3 of 18
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`DENTAL IMAGING
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`A Comparative Analysis Of Intraoral 3d Digital Scanners For Restorative Dentistry
`
`If the dentist has a standalone CEREC AC® system and he
`can not perform in-office fabrications of restorations, he can
`forward the digital impression data, using CEREC
`Connect®, directly to the dental laboratory (1).
`
`ITERO BY CADENT LTD (IL)
`The Cadent iTero digital impression system by Cadent LTD,
`IL (see Figure 6) came into the market in early 2007. iTero
`system employs a parallel confocal imaging technique (see
`Figure 7 and 8) (8). As shown in Figure 9, an array of
`incident red laser light beams 36, passing through a focusing
`optics 42 and a probing face (Figure 7 and 8), is shone on the
`teeth. The focusing optics defines one or more focal planes
`forward the probing face in a position which can be changed
`by a motor 72.
`
`
`
`target object. A focusing system 5 focuses the observation
`beam onto the image sensor 6. The light source 3 is split into
`a plurality of regions 3.1, 3.2, 3.3 that can be independently
`regulated in terms of light intensity (6). Thus, the intensity
`of light detected by each sensor element is a direct measure
`of the distance between the scan head and a corresponding
`point on the target object (3). As a disadvantage of the
`system, the triangulation technique requires a uniform
`reflective surface since different materials (as dentin,
`amalgam, resins, gums) reflect light differently. It means
`that it is necessary to coat the teeth with opportune powders
`before the scanning stage to provide uniformity in the
`reflectivity of the surfaces to be modelled.
`
`The earlier versions of CEREC® employed an acquisition
`camera with an infrared laser light source. The latest version
`employs blue light-emitting diodes (LEDs); the shorter-
`wavelength intense blue light projected by the blue LEDs
`allows for greater precision of the output virtual model (see
`Figure 4). The images are distortion-free, even at the
`periphery, so that multiple images (e.g. of a complete
`quadrant) can be stitched together with great accuracy. The
`CEREC® AC Bluecam boasts an automatic shake detection
`system which ensures that images are acquired only when
`the camera is absolutely firm. It is possible to capture a
`complete half arch in less than a minute. The new CEREC®
`AC Bluecam offers image stabilization systems. It means
`that the practitioner does not have to rest the camera wand
`on a tooth to get a steady focus and the camera automatically
`captures an image when the wand is motionless, avoiding the
`need for a pedal button (as the previous model required).
`Furthermore, it is now possible to scan full arches, while
`earlier versions of the device made a single image from one
`perspective. At the end of the scanning stage, the preparation
`is shown on the monitor and can be viewed from every angle
`to focus or magnify areas of the preparation. The “die” is
`virtually cut on the virtual model, and the finish line is
`delineated by the dentist directly on the image of the die on
`the monitor screen. Then, a CAD system, called
`“biogeneric”, provides a proposal of an idealized restoration
`and the dentist can make adjustments to the proposed design
`using a number of simple and intuitive on-screen tools. Once
`the dentist is satisfied with the restoration, he can mount a
`block of ceramic or composite material of the desired shade
`in the milling unit and proceeds with fabrication of the
`physical restoration. During the design stage of the process
`the use of colour-coded tools to determine the degree of
`interproximal contact helps to ensure finished restorations
`that require minimal, if any, adjustments before cementation.
`
`4 of 18
`
`Exhibit 1006 page 5 of 19
`DENTAL IMAGING
`
`

`

`A Comparative Analysis Of Intraoral 3d Digital Scanners For Restorative Dentistry
`
`Figure 6
`Figure 6 - iTero digital impression system (1)
`
`Figure 7
`Figure 7 - iTero system’s wand (1)
`
`
`
`Figure 8
`Figure 8 - iTero uses parallel confocal technology (10)
`
`The beams generate illuminated spots on the structure and
`the intensity of returning light rays is measured at various
`positions of the focal plane determining spot-specific
`positions (SSP) yielding a maximum intensity of the
`reflected light beams, data is generated which is
`representative of the topology of the three dimensional
`structure of the teeth (8, 9).
`
`
`
`
`
`5 of 18
`
`Exhibit 1006 page 6 of 19
`DENTAL IMAGING
`
`

`

`A Comparative Analysis Of Intraoral 3d Digital Scanners For Restorative Dentistry
`
`211
`
`n
`
`50
`
`Figure 9
`Figure 9 – iTero scanning system (8)
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`Figure 10
`Figure 10 – iTero colour imaging system (11)
`,-------------7
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`41
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`n
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`
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`• 30 e&w image
`, Ollj8CI IDpography dala
`
`
`
`X
`
`z
`
`y
`
`Using this technique iTero captures all structures and
`materials found in the mouth without the need to apply any
`reflective coating to the patient’s teeth (10). The SSP is
`always a relative position as the absolute position depends
`on the position of the sensing face. However, the generation
`of the surface topology does not require knowledge of the
`absolute position, as all dimensions in the cubic field of view
`are absolute. By determining surface topologies of adjacent
`portions from two or more different angular locations and
`then combining such surface topologies, a complete three-
`dimensional representation of the entire structure may be
`obtained (9). While the ability of the iTero camera to scan
`without the need for powders that coat the teeth may be
`advantageous, it necessitates the inclusion of a colour wheel
`into the acquisition unit itself (see Figure 10), resulting in a
`
`6 of 18
`
`camera with a larger scanner head than the other systems (1).
`In fact a two-dimensional (2D) colour image of the 3D
`structure of teeth is also taken at the same angle and
`orientation with respect to the structure. As a consequence,
`each X-Y point on the 2D image corresponds to a similar
`point on the 3D scan having the same relative X-Y values.
`The imaging process (Figure 10) is based on illuminating the
`target surface with three differently-coloured illumination
`beams (one of red, green or blue light) combinable to
`provide white light, capturing a monochromatic image of the
`target portion of teeth, corresponding to each illuminating
`radiation, and combining the monochromatic images to
`create a full colour image. The three differently-coloured
`illumination beams are provided by means of one white light
`source optically coupled with colour filters. The filters are
`arranged on sectors of a rotatable disc coupled to a motor
`(11). Capturing the digital impression follows a consistent
`series of steps for every impression. When tissue
`management has been confirmed, the operator is guided
`through a series of scanning steps. This include five scans of
`the prepared area: occlusal, lingual, buccal, and
`interproximal contacts of the adjacent teeth (1). This takes
`the operator approximately 15 or 20 seconds per prepared
`tooth. Then buccal and lingual 45°- angle views of the
`remaining teeth in the quadrant or arch and opposing arch
`are obtained. When these scans (at least 21) are complete,
`the patient is asked to close into centric occlusion and a
`virtual registration is scanned. Overall, complete upper and
`lower quadrant scans and the virtual bite registration can
`take less than 3 minutes time (1). When the digital
`impression has been completed, the clinician can select from
`a series of diagnostic tools to evaluate the preparation and
`complete the impression itself. A margin line tool is
`available to assist in viewing the clearly defined margin (12).
`The completed digital impression is sent via a HIPAA-
`compliant wireless system to the Cadent facility and the
`dental laboratory. Upon review by the laboratory, the digital
`file is output to a model by Cadent. Finally, the model is
`milled from a proprietary blended resin (1).
`
`E4D BY D4D TECHNOLOGIES LLC (US)
`The E4D Dentist system was introduced by D4D
`Technologies LLC (Richardson, TX) in early 2008. It
`consists of a cart (Figure 11) containing the design centre
`(computer and monitor) and laser scanner head (Figure 11),
`and a separate milling unit (Figure 11).
`
`
`
`Exhibit 1006 page 7 of 19
`DENTAL IMAGING
`
`

`

`A Comparative Analysis Of Intraoral 3d Digital Scanners For Restorative Dentistry
`
`
`
`Figure 11
`Figure 11- E4D Dentist system, wand and milling unit (27)
`
`Figure 12
`Figure 12- E4D scanning system (13)
`
`The IntraOral Digitizer is configured as an optical coherence
`tomography (OCT) or confocal sensor. The laser digitizer
`includes a laser source coupled to a fiber optic cable, a
`coupler and a detector (Figure 12). The coupler splits the
`light from the light source into two paths. The first path
`leads to the imaging optics, which focuses the beam onto a
`scanner mirror, which steers the light to the surface of the
`prepared tooth. The second path of light from the light
`source via the coupler is coupled to the optical delay line and
`to the reflector. This second path of light (reference path) is
`of a controlled and known path length, as configured by the
`parameters of the optical delay line. Light is reflected from
`the surface of the object, returned via the scanner mirror and
`combined by the coupler with the reference path light from
`the optical delay line. The combined light is coupled to an
`
`7 of 18
`
`imaging system and imaging optics via a fiber optic cable.
`By utilizing a low coherence light source and varying the
`reference path by a known variation, the laser digitizer
`provides an Optical Coherence Tomography (OCT) sensor
`or a Low Coherence Reflectometry sensor. The focusing
`optics is placed on a positioning device in order to alter the
`focusing position of the laser beam and to operate as a
`confocal sensor (13). A series of imaged laser segments on
`the object from a single sample position interlace between
`two or multiple 3D maps of the sample from essentially the
`same sample position. The time period to measure each
`interlaced 3D map is reduced to a short interval and relative
`motion effects between the intra-oral device and the patient
`are reduced. The interlaced 3D maps may be aligned with
`software to produce an effective single view dense 3D point
`cloud that has no motion induced inaccuracies or artefacts.
`The motion of the operator between each subframe may be
`tracked mathematically through reference points in the
`dataset itself. The operator motion is removed in subsequent
`analysis (13). The E4D does not require the use of a
`reflective agent (powder) to enable the capture of fine detail
`on the target site in most cases. The scanner must be held a
`specific distance from the surface being scanned—this is
`achieved with the help of rubber-tipped “boots” that extend
`from the head of the scanner (1). The user holds down the
`foot pedal while centring the image and when the desired
`area is centred on the on-screen bulls eye, the pedal is
`released and the image is captured. A diagram on the
`monitor shows the user how to orient the scanner to obtain
`the next image. As successive pictures are taken, they are
`wrapped around the 3D model to create a model called by
`the CEREC Company “ICEverythingTM model”. The touch
`screen monitor enables the dentist to view the preparation
`from various angles and ensure its accuracy. It is not
`necessary to scan the opposing arch.
`
`An occlusal registration is created with impression material,
`trimmed, and then placed on top of the prepared tooth. The
`scanner captures a combination of the registration material
`and the neighbouring teeth that are not covered by the
`material. This data is used to design restorations with proper
`occlusal heights. The design system of the E4D is then
`capable of auto detecting and marking the finish line on the
`preparation. Once this landmark is approved by the dentist,
`the computer uses its Autogenesis™ feature to propose a
`restoration, chosen from its anatomical libraries. As with the
`CEREC® system, the operator is provided with a number of
`intuitive tools to modify the restoration proposal. When the
`final restoration is approved, the design centre transmits the
`
`Exhibit 1006 page 8 of 19
`DENTAL IMAGING
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`

`A Comparative Analysis Of Intraoral 3d Digital Scanners For Restorative Dentistry
`
`data to the milling machine so the dentist is able to fabricate
`the completed restoration (1).
`
`Figure 13
`Figure 13- Lava C.O.S. (28)
`
`LAVA™ CHAIRSIDE ORAL SCANNER (C.O.S.)
`BY 3M ESPE (US)
`The Lava™ Chairside Oral Scanner (C.O.S.) was created at
`Brontes Technologies in Lexington, Massachusetts, and was
`acquired by 3M ESPE (St. Paul, MN) in October 2006. The
`product was officially launched in February 2008. The Lava
`C.O.S. system (Figure 13, 14) consists of a mobile cart
`containing a CPU, a touch screen display, and a scanning
`wand.
`
`The Lava C.O.S. camera contains a highly complex optical
`system comprised of 22 lens systems and 192 blue LED
`cells The Lava C.O.S. wand has a 13.2-mm wide tip and
`weighs 14 ounces (390 g) (Figure 14) (1). The Lava C.O.S.
`has introduced an entirely new method of capturing 3D data
`based on the principle of active wavefront sampling with
`structured light projection. This scanning method has been
`named “3D-in-Motion technology” by 3M ESPE. This
`scanning system provides an active three-dimensional
`imaging system that includes an off-axis rotating aperture
`element placed either in the illumination path or in the
`imaging path of an optical apparatus (14).
`
`
`
`
`
`Figure 14
`Figure 14- Lava C.O.S.’s wand (29)
`
`8 of 18
`
`Exhibit 1006 page 9 of 19
`DENTAL IMAGING
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`

`A Comparative Analysis Of Intraoral 3d Digital Scanners For Restorative Dentistry
`
`Figure 15
`Figure 15- Impression From 3M Lava COS (30)
`
`
`
`Figure 16 illustrates the principle of a three-dimensional
`imaging system having an off-axis aperture in the imaging
`path (14). To understand the theory employed in the Lava™
`C.O.S. imaging systems, Figure 17 illustrates the concept of
`measuring out-of-plane coordinates of object points by
`sampling the optical wavefront, with an off-axis rotating
`aperture element, and measuring the defocus blur diameter.
`The system includes a lens 140, a rotating aperture element
`160 and an image plane 18A. The single aperture avoids
`overlapping of images from different object regions hence it
`increases spatial resolution. The rotating aperture allows
`taking images at several aperture positions and this can be
`interpreted as having several cameras with different
`viewpoints, which generally increases measurement
`sensitivity. The aperture movement makes it possible to
`record on a CCD element a single exposed image at different
`aperture locations. To process the image, localized cross-
`correlation can be applied to reveal image disparity between
`image frames. As shown in Figure 17, at least two image
`recordings on the image plane 18A at different angles of
`rotation of the aperture 160 are used to generate the
`measured displacement for target object 8A. The separate
`images are captured successively as the aperture rotates to
`position #1 at time t and position #2 at time t+At. The
`rotation centre of the image gives the in-plane object
`coordinates as follows:
`
`where X,Y , are the in-plane object coordinates, f is the focal
`length of the lens objective, L is the depth of in-focus object
`points (focal plane), R is the radius of the circle along which
`the off-axis pupil is rotating, and d is the diameter of a circle
`along which the relevant out-of-focus point is moving on the
`image plane 18A as the aperture is rotated. The magnitude of
`the pattern movement represents the depth information (Z )
`measured from the lens plane. Z , can be evaluated from two
`Snell's lens laws for in-focus and out-of-focus object points
`and by using similar triangles at the image side (14):
`
`Figure 17
`
`I = - +
`L
`
`d(L - f)
`2RtL
`
`
`
`Figure 18
`Figure 16 – Lava C.O.S. system (14)
`
`10
`
`Optical · --
`
`Apparatus
`
`20
`
`Reay
`CCD
`Subsystem
`with Off-Axis. ii-----.1 Camera
`Aperture
`
`(2)
`
`30
`
`Rotation
`Mechanism
`
`Image
`Processor
`
`40
`
`50
`
`Figure 19
`Figure 17 – Rotation of the aperture mechanism (14)
`
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`The Lava C.O.S. allows capturing 3D data in a video
`
`9 of 18
`
`Exhibit 1006 page 10 of 19
`DENTAL IMAGING
`
`

`

`A Comparative Analysis Of Intraoral 3d Digital Scanners For Restorative Dentistry
`
`sequence and models the data in real time (approximately 20
`3D datasets per second). After the preparation of the tooth
`and gingival retraction, the entire arch is dried and lightly
`dusted with powder to locate reference points for the
`scanner. During the scan, a pulsating blue light emanates
`from the wand head and an on-screen image of the teeth
`appears instantaneously. The “stripe scanning” is completed
`as the dentist returns to scanning the occlusal of the starting
`tooth. The dentist is able to rotate and magnify the view on
`the screen, and can also switch from the 3D image to a 2D
`view (the dentist can view these images while wearing 3D
`glasses). When the dentist confirms the scan a quick scan of
`the rest of the arch is obtained. If there are holes in the scan
`in areas where data is critical, the dentist simply scans that
`specific area and the software patches the hole. The patient
`is then instructed to close into the maximum intercuspal
`position (MIP), the buccal surfaces on one side of the mouth
`are powdered, and a scan of the occluding teeth is captured.
`The maxillary and mandibular scans are then digitally
`articulated on the screen. Then the dentist sends the data via
`internet to the laboratory technician, who employs
`customized software to digitally cut the die and mark the
`margin. 3M ESPE receives the digital file, generates a
`stereolithography (SLA) model (see Figure 16) and sends it
`to the laboratory (1).
`
`IOS FASTSCAN™ BY IOS TECHNOLOGIES INC.
`(US)
`IOS Technologies, Inc. was founded in early 2007 with the
`objective of bringing it's proprietary intra-oral scanning and
`digital impression technology to market. IOS Technologies
`is currently in final development of the IOS FastScan™
`Digital Impression and Modelling System (Figure 18) and in
`July 2010 announced the IOS FastScan intraoral digital
`scanner had been advanced from prototype to production
`version and was proving successful in clinical beta testing.
`Glidewell Laboratories (CA) has been the main clinical
`testing facility for IOS Technologies' IOS FastScan. This
`initial testing has delivered promising consistency for a
`variety of dental applications, most notably with model-free
`CAD/CAM manufacture of BruxZir® Solid Zirconia crowns
`& bridges. The system’s major advantage over competitors
`is its wand (Figure 19). In fact “The IOS FastScan™ is the
`only system in which the camera moves within the wand,”
`explains Dr. Michael DiTolla, Glidewell Laboratories’
`Director of Clinical Education & Research. In fact IOS
`FastScan laser moves automatically on a track within the
`wand so the dentist only has to hold the wand in three
`positions (buccal, lingual and occlusal) to scan full arch (10).
`
`10 of 18
`
`Like Lava C.O.S. and iTero, IOS FastScan is a standalone
`scanner, so the dentist will have to work with a laboratory;
`but all the other companies require to send them the data
`because the data output format is landlord, and they charge
`about $25 for each sent virtual impression. IOS FastScan
`specializes in outputting data in sterolithography (STL)
`format, an open source data format that all the laboratories
`can recognize, open and manipulate. IOS FastScan gives the
`dentist the option of sending the data to IOS Laboratories to
`create a model at a charge of about $10 for each virtual
`impression, but if the dentist has a favourite laboratory he
`can send the virtual impression directly there. IOS FastScan
`system is based on the principle of active triangulation
`according to Schleimpflug imaging principle with sheet of
`light projection (15). Figure 20 shows an exemplary dental
`scanner head 80 that uses a polarizing multiplexer as in IOS
`FastScan™ system. The wand projects a laser sheet onto the
`teeth and then utilizes the polarizing multiplexer to optically
`combine multiple views of the profile illuminated by the
`sheet of laser light. The scanner head 80 uses a laser diode
`70 to create a laser beam that passes through a collimating
`lens 71 which is followed by a sheet generator lens 72 that
`converts the beam of laser light into a sheet of laser light.
`The sheet of laser light is reflected by the folding mirror 73
`and illuminates the surface of the target tooth. The system
`combines the light from two perspectives onto a single
`camera using passive or active triangulation (15). The
`system can be configured to achieve the independence of
`lateral resolution and depth of field. In order to achieve this
`independence, the imaging system, must be physically
`oriented so as to satisfy the Scheimpflug principle. The
`Scheimpflug principle is a geometric rule that describes the
`orientation of the plane of focus of an optical system
`wherein the lens plane is not parallel to the image plane.
`This enables sheet of light based triangulation systems to
`maintain the high lateral resolution required for dental
`applications while providing a large depth of focus (16). The
`3D scanner probe sweeps a sheet of light across one or more
`surfaces of teeth, where the sheet of light projector and
`imaging aperture within the scanner probe rapidly moves
`back and forth along all or part of the full scan path, and
`displaying a near real-time, live 3D preview of the digital 3D
`model of the scanned dentition. A 3D preview display
`provides feedback on how the probe is positioned and
`oriented with respect to the patient's dentition (16).
`
`
`
`Exhibit 1006 page 11 of 19
`DENTAL IMAGING
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`

`

`A Comparative Analysis Of Intraoral 3d Digital Scanners For Restorative Dentistry
`
`Figure 20
`Figure 18- IOS FastScan™ (31)
`
`Figure 21
`Figure 19- IOS FastScan™’s wand (32)
`
`Figure 22
`Figure 20 – IOS Fastscan scanning system (15)
`
`5
`
`71
`
`
`
`IOS FastScan™ includes a scanner to capture colour and
`translucency information along with a three dimensional
`shape of the dentition. The system also includes a computer
`aided design (CAD) module to receive the colour and
`translucency information and the 3D shape to render a
`colour accurate representation of the prosthesis. The colour,
`translucency and surface information is combined in a single
`digital prescription which is electronically transferred to a
`laboratory or CAD/CAM system for fabrication (17). The
`virtual model can be trimmed, the margin can be marked,
`and the die quickly and easily ditched using the IOS
`FastScan™ Dental CAD software.
`
`
`
`11 of 18
`
`Exhibit 1006 page 12 of 19
`DENTAL IMAGING
`
`

`

`A Comparative Analysis Of Intraoral 3d Digital Scanners For Restorative Dentistry
`
`DENSYS3D BY DENSYS LTD (IL)
`Densys3d is a chair-side, standalone unit, comprising of a
`PC, a flat screen and a small hand held intra-oral camera,
`creat