Special Reprint Cover

Since Cerec (Chairside Economical Restoration of Esthetic Ceramics) was introduced as the first dental chairside computer-aided design/computer-aided manufacturing (CAD/CAM) system in the mid-1980s, this technology has enjoyed growing popularity, particularly in the recent past. There has been a considerable increase in the number of available chairside systems in only the last few years. One of the main reasons for this is that intraoral scanners have become increasingly better, smaller, and faster, while the design software has become more and more user-friendly. Many work steps are now automated, and a very large range of materials is now available for dental chairside applications. These advances have driven the rapid increase in the range of indications for chairside dentistry in the areas of prosthodontics, dental implantology, and orthodontics, and have paved the way for more novel treatment and treatment planning strategies. Another reason is that intraoral scanner-based digital impression techniques are already superior to conventional impression techniques in certain respects. Moreover, the quality of fit of digitally designed dental restorations is constantly improving because of advances in milling machine technology.

Due to the sheer number of new possibilities, it is only a matter of time before chairside systems become a standard component of dental practice. This article reviews the actual advantages and limitations of the chairside workflow, and provides a summary of all the available chairside systems available today (Int J Comput Dent 2017(13); 2; 123-1492).

Author: Markus Zaruba and Albert Mehl

Access provided by Henry Schein

Introduction

Products available through Henry Schein:

Dentsply Sirona

CEREC AI with Omnicam

CEREC Connect with Omnicam

 CEREC MC milling unit

CEREC MC X milling unit

CEREC MC XL Practice Lab Milling Unit

Planmeca

PlanScan Scanner

PlanCAD Design Center

PlanMill 30 S

PlanMill 40

PlanMill 40 S

3Shape

Implant Studio™

TRIOS® 3 Cart

TRIOS® 3 Cart – Handle Grip

TRIOS® 3 Cart – Wireless

TRIOS® 3 Monochrome Pod – Pen Grip

TRIOS® 3 Pod

TRIOS® 3 Wireless Pod – Pen

TRIOS® Design Studio

TRIOS® MOVE

Chairside implies the fabrication of dental restorations directly after tooth preparation during a single appointment.1,2 Purely chairside systems for dentistry have been available for more than 30 years, the first being the Cerec system. This was the only available system for many years, until the second fully chairside system was introduced in 2008 by E4D. Many new intraoral impression systems are now available to dentists due to rapid developments and improvements in the area of intraoral scanner technology, but only a few fully chairside systems for dental applications have been introduced in the last few years. A recent study revealed that only 5% to 15% of dentists use digital impression technologies; most still use conventional impression techniques.3 Nevertheless, the use of digital impression systems has many advantages. Several studies have demonstrated that their accuracy is sufficient to ensure the success of the clinical process chain.4-7 Moreover, there are many new processing options for digital datasets, some of which were possible but often extremely time consuming with conventional impression techniques. These include cutting tools and supplementation functions, as well as analysis modes such as wear or recession measurement.8,9 Many software improvements have accompanied these advances. For example, many work steps are now fully automated and computed in the background, making it possible to produce high-quality restoration proposals for direct milling/grinding in only a few mouse clicks. At the International Dental Show (IDS 2017), many manufacturers announced new and improved milling units for chairside dentistry, as well as new dental materials.

It is only a question of time before digital impression technologies replace conventional impression techniques. The real question that dentists should ask themselves today is: “When is it a good time to start using dental impression technology, and to what extent would this make sense for me, my team, and my practice management strategy?”

This review article is intended to provide valuable information to support this decision-making process, and to describe the advantages and limitations of chairside dental computer-aided design/computer-aided manufacturing (CAD/CAM) systems. It also provides a short description of all currently available, fully chairside dental CAD/CAM systems presented at the (IDS 2017), a principal theme of which was the digital chairside workflow.

Advantages of the chairside workflow

Modern chairside systems offer significant advantages over conventional or traditional workflows for dental restorations, as described below:

Real-time scanning and visualization of impressions:

The quality of optical impressions and tooth preparations can be analyzed immediately after intraoral scanning based on the computed digital model. In most cases, errors in conventional impressions can only be detected on the plaster cast and cannot be reversed at that stage.

Easy repeatability:

If a digital model contains errors, a digital impression of the defective section can be recaptured directly, or the entire intraoral scanning process can easily be repeated. This can be done in real time and does not require any readjustment of an impression tray or mixing and setting of impression material.

Selective repeatability:

In contrast to conventional impression methods, intraoral scanning can be selectively repeated in the area where the error occurred (eg, due to bleeding at the preparation margin). This is easily accomplished by digitally cutting out and rescanning the area in question.

Pre-scan option:

Preliminary full-arch scans can be acquired in the planning stage. The teeth to be prepared can be cut out of the pre-scan and rescanned after preparation.

No impression tray to clean and disinfect:

Intraoral scanners are easy to disinfect. Some have disposable tips, while others use autoclavable scanning tips or single-use disposable sleeves. This eliminates the time-consuming task of cleaning and disinfecting an impression tray.

Preparation and restoration analysis options:

Important preparation and restoration parameters such as the insertion axis, undercuts or the distance to the antagonist (minimum layer thickness) can be checked directly on the digital model.

No cast wear and tear:

Unlike plaster casts, digital models are not subject to wear and tear (during occlusal analysis, etc) and are continuously available for repeated processing in unchanged quality.

Rapid communication and availability:

Digital models can be sent to a dental laboratory or milling center via the internet within seconds. The dataset can also be sent via a cloud service. This minimizes the loss of time and eliminates transport and delivery fees.

Archivability:

Digital impression datasets can be archived much more easily and efficiently than conventional casts. No room is needed for cast storage. Patient files can be quickly and easily located and opened using the search function.

Material savings:

No impression material is needed for digital impressions. This offers advantages in terms of sustainability, resource conservation, and storage.

Chairside treatment:

Apart from saving time, single-visit chairside treatment offers many advantages. For example, it enables immediate sealing of the dentin wound from bacteria and adhesive stabilization of the remaining tooth structure, and ensures that the adhesive bond is not compromised by temporary cement.

Patient satisfaction:

Chairside CAD/CAM dentistry dispenses with the need for temporization, a second appointment, and additional anesthetics. Many patients appreciate the fact that they receive treatment and the final restoration on the same day. This saves the patient a lot of time, travel, and waiting.

No temporary restoration:

The time-consuming fabrication of a temporary restoration is not required in chairside treatment. Hence, there is no temporary restoration that could be lost. Also, cusp fractures are avoided and the tilting of adjacent teeth or antagonists cannot occur.

Digital follow-up and analysis:

In contrast to conventional casts, digital models make it possible to perform numerous intraoral analyses for the identification of changes such as tooth migration, tipping, rotation or abrasion, and gingival recession. Three-dimensional (3D) comparison of the respective baseline findings with intraoral follow-up scans made using a suitable software tool (eg, OraCheck; Cyfex, Zurich, Switzerland) is sufficient for this purpose.

True-color display:

Some intraoral scanning systems now generate true-color models, allowing for improved visualization of characteristics of tooth structure and gingival texture, etc. The system can then analyze the gums and teeth for color differences, which is not possible with plaster casts. Selective tooth shade measurement is also possible with some systems.

Implant treatment planning capability:

Digital datasets can be merged with other datasets, such as those from facial scanning or 3D radiography (conventional, or cone beam computed tomography [CBCT]). This allows the user to perform additional, extended, and, above all, more comprehensive diagnostic and treatment-planning studies as needed for guided surgery or smile design, etc.

Cost effectiveness:

Since the restorations are produced in the dental practice or the in-house dental laboratory, the added value remains in the owner’s own practice.

Limitations of chairside systems

Although the use of chairside systems offers numerous advantages, especially in the case of digital impressions, there are some limitations associated with intraoral scanning followed by the fabrication of dental restorations, as described below:

Learning curve:

Until the user learns the specific scanning paths that must be observed, it is difficult to acquire good optical impressions. Optical impression scanning techniques are therefore subject to a learning curve. However, so-called guided scanning software programs that give the user step-by-step instructions on how to guide the intraoral scanner across the arch during the scanning process facilitate the procedure and are already integrated into some systems.

Dry working field:

The basic rule for all optical intraoral scanning systems is: The camera can see and capture everything you can see with your own eyes, regardless of whether these areas are located subgingivally or not. Therefore, the preparation margins must be readily visible and free of saliva, sulcus fluid, and blood, as the presence of these liquids results in errors due to differences in light refraction in a liquid medium.

Implant impressions:

An implant-specific scan body is needed for the precise determination of implant position with digital impressions acquired using intraoral scanners. The scan body must be compatible with the specific implant system and CAD/CAM software used. However, more and more chairside systems have started to offer compatible solutions for a large number of implant systems in recent years.

Static and dynamic occlusion:

Some intraoral scanning systems do not allow for later adjustment of bite position. When extensive restorations are to be fabricated, these systems reach the limits of their capacity as soon as the former support zones are lost. Many systems do not have the capability to simulate dynamic occlusion. However, more and more design software packages have an integrated digital mean value or even fully adjustable articulator. Some allow for the use of individual articulation parameters and for the digital adjustment of bite position by means of a support pin.

Scan fees and closed systems:

Only those dental chairside systems with certified, manufacturer-approved, official chairside workflows that normally are not subject to scan fees are included in this review. However, it should be borne in mind that additional costs may still be incurred for software upgrades or annual fees for software use. On the other hand, some manufacturers charge scan fees for each digital scan captured on purely intraoral scanners. In many cases, the scan data is first sent in an encrypted format to a cloud storage system owned by the cloud storage company, which constitutes a closed system. Therefore, open export of the STL data for further processing with the desired CAD software is only possible after exporting the file from this platform, if at all possible. However, manufacturers are increasingly starting to offer open systems, ie, intraoral scanners that allow direct STL data export.

Cost:

Since a dental chairside system is a substantial financial investment, dentists should thoroughly consider the indications for which such a system would be used in their dental practice before purchasing the equipment. The wider the range of indications and more frequent the opportunities for using the chairside system, the more worthwhile the investment in this equipment would be. The deciding factors would vary from one practice to another. Costs are not mentioned in this review because the prices of dental chairside systems differ by system configuration and country.

Scanning strategy:

The quality of the results of intraoral scanning is dependent not only on the range of different technical features offered by an intraoral scanner, but also on the use of an appropriate scanning strategy. Studies have shown that the scanning strategy influences the accuracy of intraoral data acquisition. The scan path is defined as the specific movement pattern through which an intraoral scanner must be guided in order to produce a digital model with the greatest accuracy possible. This is particularly important when scanning a large area, such as a quadrant or a full arch. Unstructured and/or steeply sloping areas, such as the mandibular anterior region, are often difficult to scan properly and require the use of a system-specific scanning strategy. For this reason, it is important that users always personally test the scanner in question and read the technical specifications.

CAM – the art of material processing:

Instrument diameter, grain size, and geometry are important factors for fabricating dental restorations with a good quality of fit. The use of fine instruments increases accuracy when machining restoration margins and fine detail. Wet grinding is generally better for glass ceramic restorations, while dry grinding is advantageous for zirconia restorations. Unlike 4-axis milling machines, 5-axis milling machines can handle undercuts.

Overview of chairside systems

Table 1 summarizes the chairside systems that are currently on the market, while making no claim to completeness. The list of these systems is arranged in alphabetical order by manufacturer. This is followed by a list of validated and official collaborations between manufacturers with established chairside workflows. The currently available configurations and camera sizes for each chairside system are also indicated. Features such as powder-free or powder-based scanning, true-color display, scanning mode, and scanning principle are listed for each intraoral scanner system. The file formats used for scan data export, and the CAD/CAM software types used for the chairside workflow are also specified. All chairside systems need a milling machine or CAM unit in order to fabricate the designed restoration. The size, weight, and number of axes and spindles, as well as their rotational speed, is specified for each grinding/milling machine. Also indicated are the types of materials that can be milled (usually supplied in blocks), their maximum lengths, and whether wet or dry grinding is performed. Although the manufacturer-specified milling time for a crown is given, this time can vary greatly depending on the type of material, the size of the restoration, and the degree of instrument wear. Logistic factors important for in-office integration, including the availability of a water and compressed air supply for the CAM unit, should also be considered.

CS 3500, CS 3600 & CS 3000
(Carestream Dental, Rochester, NY, USA)

Carestream Dental launched its new CS 3600 intraoral  scanner at the IDS 2017. As with the CS 3500 intraoral scanner, the CS 3600 can be used together with the CS 3000 milling machine to complete a CAD/CAM chairside workflow. Both intraoral scanners use triangulation technology for optical imaging. The CS 3500 captures still images, and the CS 3600 captures video sequences. Both feature powder-free scanning and true-color display. The CS 3600 is the faster of the two scanners. Both scanners come in two versions that can either be connected to a laptop via USB, or integrated into the treatment unit. CAD/CAM workflows can be completed using the company’s proprietary CS Restore software or CS Connect cloud platform. This enables a laboratory based workflow or STL data export for completion of the chairside workflow. The CS 3000 milling machine uses a 4-axis motor to produce single-unit restorations from zirconia, glass ceramic or hybrid ceramic material, as well as from polymethyl methacrylate (PMMA) or composite material. The average time required to wet grind a single-unit crown is approximately 15 minutes. The milling machine has an integrated water and compressed air supply.

DWIO & DWLM
(Dental Wings, Montreal, Canada)

The Canadian manufacturer Dental Wings presented its chairside system at the IDS 2017, which consists of the Dental Wings IntraOral (DWIO) scanner in combination with the DW Lasermill (DWLM) milling machine. The intraoral scanner operates using the company’s proprietary Multiscan Imaging technology, a further development of the triangulation principle. By the differential spatial alignment of 10 cameras, the system is able to record black points projected by five projectors onto the tooth surfaces from multiple perspectives. The version announced at the IDS 2017 features powder-free scanning, but does not offer true-color display. The small and lightweight scanner is supplied as an intraoral scanner cart with a touchscreen. Also available is a portable tablet version. It also features special gesture recognition technology for completely touch-free operation of the system by means of “motion capturing.” The user can complete the digital workflow by directly using the DWOS Chairside software, or by sending the data via the cloud using the DWOS Connect platform. Open export of STL file format is thus possible. The DWOS Chairside software can also be used to operate the CAM unit. DWLM uses laser ablation technology to fabricate single-unit restorations made of glass ceramic, PMMA, composite, and hybrid ceramic materials. The milling unit operates using laser pulses along six independent axes. Since it only performs dry milling, the unit does not need a compressed air or water supply – a standard electrical supply is all that is needed.

Cerec Omnicam & Cerec MC, X, and XL
(Dentsply Sirona, York, PA, USA)

Dentsply Sirona has expanded its intraoral scanner product line to include a Cerec Omnicam version called Cerec AI (Acquisition Integration), which was launched at the IDS 2017. It and the Cerec AF (Acquisition Flex) flexible table unit are integrated into the treatment center. The Apollo DI digital impression system and the Cerec Bluecam are no longer included in the product portfolio. The intraoral scanners feature powder-free scanning and full-color display based on the optical triangulation principle. The Cerec SW 4.X or Cerec Premium software is used to accomplish the chairside workflow. The Cerec SW 4.5 software presented at the IDS 2017 can be used to calibrate the Omnicam. This allows the system to analyze a scan via its “Shade Detection” function, and select the appropriate tooth color from a specific shade guide (eg, Vita Classic). A “Guided Scanning” function for full-arch scanning will be integrated into the software in the third quarter of this year. Direct export of STL model data is another new feature. The Cerec MC, X, and XL 4-axis milling units are controlled directly via the chairside software. Depending on the configuration, blocks in lengths of up to 20 mm (MC), 40 mm (MCX), or 85 mm (MCXL) can be wet or dry milled. Water and compressed air are integrated into the milling units, which can mill out crowns made of zirconia, glass ceramic, PMMA, composite, or hybrid ceramic materials within 10 minutes. The MCXL can also process cobalt chrome (CoCr) blocks.

myCrown Scan & myCrown Mill
(Fona Dental, Bratislava, Slovakia)

Dentsply Sirona produces and markets dental products for specific regions on the world market under the Fona brand. This year, Fona presented its own chairside system at the IDS 2017 for the first time. The system’s small and easily manageable intraoral camera comes with a cart. Tooth surfaces must be lightly powdered before scanning. Digital models are created using video sequences based on stereophotogrammetry. After light powdering, the color of the surfaces showing through the thin layer of powder can also be captured. Chairside restorations are designed with the help of the myCrown Design software. The user can send design proposals directly to the Fona myCrown Mill 4-axis milling unit, which can wet mill restorations out of blocks of up to 40 mm in length within 12 minutes. A water tank and compressed air supply are integrated into the compact milling unit. Zirconia, glass ceramic, PMMA, and composite materials can be processed.

PlanScan, Emerald & PlanMill
(Planmeca, Helsinki, Finland)

Finnish manufacturer Planmeca presented its Emerald camera at the IDS 2017 as a new development, in addition to its previous PlanScan intraoral scanner. Planmeca has a fully established chairside workflow, consisting of the PlanScan intraoral scanner, in combination with the PlanMill 40 S or the smaller PlanMill 30 S milling unit. The PlanScan intraoral scanner is a further improvement on the E4D system, which was formerly marketed only in the USA, whereas the Planmeca Emerald is a completely new lightweight intraoral scanner. Both feature powder-free scanning and true-color display based on surface triangulation technology. The scanners capture video sequences. Planmeca Emerald should be available in the third quarter of 2017. It is significantly smaller, faster, and lighter than the Planmeca PlanScan. Both intraoral scanners are available in two versions that are either integrated into the Planmeca dental unit or can be connected to a laptop via USB. Planmeca PlanCAD Easy CAD software is used to program the chairside workflow. The Planmeca Romexis cloud system enables open export of STL data. The chairside software can be used to control the new Planmeca PlanMill 40 S and 30 S milling units. Both have a 4-axis motor and an integrated tool changer. The 30 S can handle blocks of up to 85 mm in length, and the 40 S can handle blocks of up to 40 mm. The milling time for glass ceramic, PMMA, composite, or hybrid ceramic material is 16 to 18 minutes per restoration for the 30 S, and 8 to 10 minutes for the 40 S. Both have an integrated water tank, but require an external compressed air supply.

IntraScan & Inhouse5x wet & dry
(Zfx, Dachau, Germany)

In addition to its well-known IntraScan intraoral scanner, Zfx also provides a compact 5-axis milling machine that weights 220 kg. The lightweight (600 g) IntraScan intraoral scanner features powder-free scanning and captures the tooth surfaces in video sequences by means of confocal microscopy. IntraScan is only available as a laptop-to-USB system. The digital workflow is accomplished via direct STL export using the Zfx Dental-Net online platform (cloud) and the Zfx CAD design software, which has 5-axis milling strategies integrated into the software. Zfx hyperDENT CAM software is used to control the Inhouse5x wet & dry milling machine, which can perform simultaneous 5-axis milling. Blanks and blocks can be clamped in a blank holder with up to 15 units, and both wet and dry machining can be performed. The milling machine can process zirconia, PMMA, glass ceramic, wax, CoCr, and titanium materials. A tool magazine that can automatically change up to 28 tools and an integrated camera allow for in-house fabrication. The machine requires an external water and compressed air supply.

Chairside cooperation partnerships

Trios 3 Wireless (3Shape, Copenhagen, Denmark)

The Danish company 3Shape presented three different cooperation partners for the direct chairside workflow at the IDS 2017. The partner companies will use the 3Shape Trios 3 Wireless intraoral scanner and design software for digital impression scanning. Some of the partner companies have their own chairside CAM software for specific milling machines. The presentation of this first wireless intraoral scanner at the IDS 2017 was a world premiere. The Trios 3 Wireless intraoral scanner comes with a handle grip or a pen grip. It is available in a cordless, battery powered version or a corded version. Trios intraoral scanners can be purchased as a Trios Cart version with a touchscreen, or as a Trios Pod version that can be connected to a laptop via USB, or can be integrated into the dental unit. Like its predecessors, the Trios 3 Wireless intraoral scanner features integrated digital shade measurement, and captures video sequences by means of confocal microscopy. In addition to a cutting function, it has a blocking function designed to protect surfaces that should not be altered during later scanning. STL data files can be exported via the cloud or via an in-house computer system. The new 3Shape Communicate App, which allows dentists to communicate directly with laboratory technicians across devices, was also introduced at the IDS 2017. Since the IDS 2017, 3Shape has had three cooperation partners handling the chairside workflow: Straumann and Ivoclar Vivadent use the 3Shape Trios Design Studio chairside dentistry software, and Lyra uses the 3Shape LAB Praxis software. In addition to these chairside dentistry software solutions, 3Shape supplies other modules, such as 3Shape Implant Studio, 3Shape Orthodontics, and Trios Digital Patient Monitoring (DPM) software.

PrograMill One (Ivoclar Vivadent, Schaan, Liechtenstein)

Ivoclar Vivadent introduced three new laboratory milling machines as well as the PrograMill One chairside milling machine at the IDS. In cooperation with 3Shape, Ivoclar Vivadent offers an established chairside workflow that includes the newly introduced Trios 3 Wireless intraoral scanner. 3Shape Trios Design Studio CAD software is used to design and mill chairside restorations. Alternatively, milling/grinding (CAM) can be performed using the Ivoclar PrograMill CAM V4 software, which is now available as an app (PrograMill One App) for end devices. According to the manufacturer, the PrograMill One is the world’s smallest 5-axis milling machine: it weighs only 36.5 kg and has a tool changer for up to 8 tools as well as a material changer for up to 5 materials. It operates using the 5-axis turn-milling technique (5XT), in which a clamped block of material rotates in all axes around the milling tool seated in the spindle. Blocks of various Ivoclar materials (IPS e.max CAD/ZirCAD, IPS Empress CAD, Telio CAD) of up to 45 mm in length (wet milling) can be processed using various milling strategies. The PrograMill One App enables wireless communication from anywhere within the lab, and provides information about the current machine status. According to the manufacturer, this is Digital Dentistry 4.0.

Lyra Mill (Lyra, Paris, France)

Lyra, a French manufacturer, collaborates with 3Shape to provide a validated chairside workflow. The company introduced a compact 4-axis milling machine called the Lyra Mill at the IDS 2017. This workflow uses the 3Shape LAB Praxis CAD/CAM software, and the 3Shape Trios 3 intraoral scanner. The Lyra Mill has a block holder that secures blocks of up to 40 mm in length, and processes blocks of glass ceramic, PMMA, composite, and hybrid ceramic materials. It can only perform wet milling/grinding. This compact milling machine has an integrated water and compressed air supply.

Cares C series (Straumann, Basel, Switzerland)

Straumann, one of the leading manufacturers of dental implantology products, announced at the IDS 2017 that it is offering a new, established chairside workflow in collaboration with two cooperation partners for digital impressions. In collaboration with Dental Wings, digital impressions are made with the newly introduced DWIO or 3Shape Trios 3 Wireless intraoral scanner. Depending on which scanner is used, the design process is accomplished using either the 3Shape Trios Design Studio software or the Straumann Cares Visual solution, from Straumann in cooperation with Dental Wings. The restorations are digitally designed with these software packages and milled with the Straumann Cares C series compact 4-axis milling machine. The milling machine was developed in cooperation with Amann Girrbach. It has a one-block material holder and can mill or grind restorations out of glass ceramic and hybrid ceramic blocks (length: ≤ 40 mm) within 15 minutes. The unit has an integrated tool changer and water tank.

Discussion

Modern intraoral scanners make it possible to capture single-tooth as well as quadrant10 and full-arch digital impressions, and to produce digital models11 and restorations12 with high accuracy. However, it must be considered that the use of the proper scanning strategy for a given scanning system has a considerable impact on accuracy.13-14 Until now, the only limitations have been purely implant-restored and full-arch scans,15 but recent studies have achieved good results in these indications.16,17 Dentists now have a variably comprehensive range of treatment options, which may include the prosthetic reconstruction of implants and all-zirconia bridges in only one appointment, depending on the chairside system used. Studies have shown that the quality of fit of CAD/CAM single-unit crowns, bridges, and frameworks fabricated using digital impressions made with intraoral scanners is as good as, or even better than, those fabricated using conventional impressions.6,18 As the quality of intraoral scanners is constantly improving, one can assume that further advances in the chairside systems presented in this article, as well as in their new or improved milling/grinding machines with improved machining algorithms, are sure to come. Considering the advantages and disadvantages of the chairside systems discussed here, the most important questions that dentists should consider before entering the field of chairside dentistry are:

Are you sure you want to make in-office chairside restorations? If not, an intraoral scanner could be a good alternative, as you would then only have to make the intraoral impressions and send the data to a laboratory.

If you do want to make in-office chairside restorations, you need to consider what exactly you intend to fabricate with this technology. Do you want to make single tooth restorations, implant-supported crowns and bridges, and/or surgical guides? The various chairside systems have different modules that can be combined as needed. It is therefore important to evaluate the individual acquisition costs carefully before deciding which system to purchase.

What kind of restorative materials do you anticipate processing with your new chairside system? Since many manufacturers have material partnerships with other companies, and because not all milling machines are able to mill and grind all types of restorative materials, it is imperative to perform a careful needs analysis before making a purchasing decision.

What will your strategy be for integrating the chairside workflow into your dental practice? Do you intend to do the scanning and designing yourself? Will an assistant dentist or your own in-house dental technician handle the staining work? How will you use the time during the interval when the restoration is being produced in the milling/grinding machine? Chairside treatment is a team approach and should be managed and communicated with the practice team.

Is the envisaged chairside technology an open or closed system? The advantage of an open system is that scan datasets can be saved in STL format for further CAD/CAM processing. This is useful, for example, in cases where the in-house milling unit is unable to handle large restorations or certain types of material. On the other hand, almost all systems nowadays are open export systems.

Therefore, it is important to know which implant systems are compatible with a specific intraoral scanning system or CAD/CAM software.

Should the datasets be compatible with other digital systems, such as CBCT?

How good is the technical support for a given system? There are many questions to consider, especially at the beginning of this process. It is also important to attend training events organized by the specific system manufacturers or specialized dental societies.

Summary

This summary and review of the available dental chairside systems is intended to help interested dentists to answer these questions. Scientific research has shown that intraoral digital impressions and also the entire digital process chain are already superior to conventional techniques in many respects, and that software improvements are making it increasingly easier for dentists using this equipment to make chairside restorations in their own dental practices in a single appointment. A further increase in the range of indications for chairside dental technology can be expected in the future due to the greater integration of digital systems into diagnostic and therapeutic strategies, and therefore it is very likely that chairside dental systems will become even more widespread.

References

  1. Mörmann WH. The origin of the Cerec method: a personal review of the first 5 years. Int J Comput Dent 2004;7:11–24.
  2. Mörmann WH. The evolution of the Cerec system. J Am Dent Assoc 2006;137(suppl):7S–13S.
  3. Joda T, Brägger U. Patient-centered outcomes comparing digital and conventional implant impression procedures: a randomized crossover trial. Clin Oral Implants Res 2016;27:e185–e189.
  4. Ender A, Mehl A. In-vitro evaluation of the accuracy of conventional and digital methods of obtaining full-arch dental impressions. Quintessence Int 2015;46:9–17.
  5. Ender A, Mehl A. Full arch scans: conventional versus digital impressions – an in-vitro study. Int J Comput Dent 2011;14:11–21.
  6. Seelbach P, Brueckel C, Wöstmann B. Accuracy of digital and conventional impression techniques and workflow. Clin Oral Investig 2013;17:1759–1764.
  7. Patzelt SB, Emmanouilidi A, Stampf S, Strub JR, Att W. Accuracy of full-arch scans using intraoral scanners. Clin Oral Investig 2014;18:
    1687–1694.
  8. Zaruba M, Ender A, Mehl A. New applications for three-dimensional follow-up and quality control using optical impression systems and OraCheck. Int J Comput Dent 2014;17:53–64.
  9. Mehl A, Koch R, Zaruba M, Ender A. 3D monitoring and quality control using intraoral optical camera systems. Int J Comput Dent 2013;16:23–36.
  10. Ender A, Zimmermann M, Attin T, Mehl A. In vivo precision of conventional and digital methods for obtaining quadrant dental impressions. Clin Oral Investig 2016;20:1495–1504.
  11. Ender A, Mehl A. In-vitro evaluation of the accuracy of conventional and digital methods of obtaining full-arch dental impressions. Quintessence Int 2015;46:9–17.
  12. Bosch G, Ender A, Mehl A. Non- and minimally invasive full-mouth rehabilitation of patients with loss of vertical dimension of occlusion using CAD/CAM: an innovative concept demonstrated with a case report. Int J Comput Dent 2015;18:273–286.
  13. Ender A, Mehl A. Influence of scanning strategies on the accuracy of digital intraoral scanning systems. Int J Comput Dent 2013;16:11–21.
  14. Müller P, Ender A, Joda T, Katsoulis J. Impact of digital intraoral scan strategies on the impression accuracy using the Trios Pod scanner. Quintessence Int 2016;47:343–349.
  15. Ahlholm P, Sipilä K, Vallittu P, Jakonen M, Kotiranta U. Digital Versus Conventional Impressions in Fixed Prosthodontics: A Review. J Prosthodont 2016 [epub ahead of print 2 Aug 2016]. doi: 10.1111/jopr.12527.
  16. Vandeweghe S, Vervack V, Dierens M, De Bruyn H. Accuracy of digital impressions of multiple dental implants: an in vitro study. Clin Oral Implants Res 2016 [epub ahead of print 6 May 2016]. doi: 10.1111/clr.12853.
  17. Amin S, Weber HP, Finkelman M, El Rafie K, Kudara Y, Papaspyridakos P. Digital vs. conventional full-arch implant impressions: a comparative study. Clin Oral Implants Res 2016 [Epub ahead of print 31 Dec 2016]. doi: 10.1111/clr.12994.
  18. Tsirogiannis P, Reissmann DR, Heydecke G. Evaluation of the marginal fit of single-unit, complete-coverage ceramic restorations fabricated after digital and conventional impressions: A systematic review and meta-analysis. J Prosthet Dent 2016;116:328–335.