issn 2193-4673 • Vol. 1 • Issue 1/2021 1/21 3D printing international magazine of dental printing technology p r e v i e w news Benefi ts of in-house 3D printing clinical Guided applications for partial extraction therapy industry report 3D printing: Changing the game

editorial | Dr George Freedman Editor-in-chief 3D printing in dentistry: Revolution in progress 3D dental printing today is reminiscent of cosmetic dentistry in the early 1980s: the needs are many, the technologies are numerous, the applications almost unlimited and the poten- tial open-ended. Just as cosmetic materials and techniques brought aesthetic restorative dentistry into the hands of every practitioner, 3D printing promises to bring the functional and ar- tistic control of the restorative process into the chairside setting. Stereolithography, first developed in the 1980s, was soon fol- lowed by additive manufacturing, the deposition of material in increments. Dental applications are more recent. 3D printing has been utilised for rapid prototyping and modelling for more than a decade. The size and cost of the earlier printers meant that they were limited to larger laboratories. The digital transformation of dentistry, including CBCT, intra- oral and extra-oral scanning, milling of ceramic and compos- ite materials, and robotic implant placement, is firmly estab- lished. Linking with these advances, the most recent desktop printers have a much smaller footprint, are easily affordable for the single practitioner, communicate with existing software platforms and offer high levels of precision with a wide range of materials. Current 3D printers are fully capable of managing the great de- mand for temporary, transitional, and permanent restorations and appliances and of achieving the clinical excellence re- quired by the dental profession. Consequently, there has been a growing acceptance of this transformative technology. In- creasingly, 3D printing is viewed as an industry game-changer and a forecast of the future direction of the dental practice. 3D-printing techniques include stereolithography, fused depo- sition modelling, selective laser sintering, powder binder print- ing, photopolymer jetting, electron beam melting and direct light processing. These currently unfamiliar names will soon become standard dental terminology. The documented, wide-ranging 3D printing applications can be grouped by treatment category: – Fixed prosthodontics: Permanent and provisional indirect restorations (crowns, onlays, inlays, bridges) and permanent monobloc direct restorations can all be custom-fabricated chairside within minutes of scanning the preparation. – Removable prosthodontics: Both complete and partial dentures, including digital occlusal design, are deliverable within hours. – Implant dentistry: 3D printing of surgical guides has facilitated ideal implant positioning. Biomimetic custom 3D-printed bone implants replace missing segments, minimising stress transfer to the remaining bone. – Orthodontics: Aligners, designed using CBCT data and arti- ficial intelligence extrapolation of tooth movement over time, are 3D-printed. – Endodontics: The pioneering 3D-printed endodontic access guide, utilising CBCT data, translates pre-surgical planning into clinical success. – Maxillofacial surgery: Custom-designed bone grafts and fix- ation plates expedite both the surgical procedure and the healing process. – Periodontics: 3D-printed guides that relieve and retract gin- gival margins offer aesthetic gingival correction. Soft-tissue printing is currently in the research phase. 3D-printing techniques and procedures are high-quality, high precision and accurate and significantly lower in cost than con- ventional treatment options. Dentists save money: many desk- top printers cost between US$3,000 and US$10,000, and den- tal 3D-printing materials cost pennies per tooth. Patients save money, by the elimination of intermediate procedures and trans- portation costs. Treatment is faster, typically same-day services. Welcome to 3D printing! Welcome to the future of dentistry. Dr George Freedman Editor-in-chief 3D printing 1 2021 03

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interview | 3D printing is a powerful technology on its own, but the real impact comes from the people who use it. We see new 3D printing applications all the time, whether they are born of necessity or innovation. That is why Formlabs is committed to increasing access to powerful digital technology. What are some of the criticisms of dental 3D printing, and do the benefits offered by using 3D printing out- weigh the associated risks? Ten years ago, the biggest problem with 3D printing was the prohibitively high cost of a printer. Luckily, with the success of manufacturers such as Formlabs in the mar- ket, printers are more affordable, more reliable and easier to use than ever before. Now, the only risk lies in having false expectations. A 3D printer is a piece of equipment, and learning to use a desktop unit like the Form 3B is easy, but it does take some time. Those who choose to adopt digital technol- ogy should embrace the learning curve, ask for advice from their peers and seek out professional development opportunities. Moving forward, 3D printing needs to overcome the den- tal industry’s skepticism about novel printing materials and applications such as printed dentures and perma- nent restorations. Manufacturers like Formlabs need to be proactive about teaching experts and validating new technology in the industry in order to achieve a mindset shift. But it will eventually happen. We have already seen it many times in the dental industry. Implants, zirconia, intraoral scanners, chairside milling and many other ma- terials and technologies overcame the initial skepticism. I am glad to be part of the movement that is leading and revolutionising digital dentistry. Georgio Haddad, dental strategic partnerships and initiatives lead at Formlabs, a 3D-printing technology developer and manufacturer. (Image: © Georgio Haddad) “3D printing is a powerful technology on its own, but the real impact comes from the people who use it.” Editorial note: The Formlabs Dental webinar, titled “Revo- lutionizing digital dentistry with 3D printing—accessible solutions and new applications,” is available on demand at www.dtstudyclub.com. Registration is free of charge. Formlabs’ Form 3B printer. (Image: © Formlabs Dental) 3D printing 1 2021 07

news | ratory after virtual surgical planning. The remaining patients each received a prosthesis that was designed by a surgeon and 3D-printed via the in-house laboratory. The researchers fabricated a dental prosthesis using point- of-care 3D printing within 24 hours of the virtual surgi- cal planning session. The time required to generate the in-house 3D-printed prostheses was significantly shorter when compared with dental laboratory-fabricated prosthe- ses, which typically take weeks. Additionally, the procedure was more cost-effective. Whereas the prostheses created by an off-site dental laboratory averaged $617.00, each in-house 3D-printed prosthesis cost an average of $8.34 for resin, and the researchers noted that a full-arch pros- thesis 3D-printed in NextDent Micro Filled Hybrid costs under $50.00. The price includes the costs for the resin and the export fee for Blue Sky Plan, a 3D-printing software. “The study describes a digital workflow to design and 3D-print an immediate provisional dental prosthesis to be placed during jaw reconstruction when using a fibular free flap. This surgery has been called ‘Jaw in a Day.’ Previous methods involved third-party dental laboratories which require additional time, laboratory expertise and are more expensive. Our technique allows surgeon-guided virtual planning, just like we do with the jaw and fibula,” Dr Fayette C. Williams, fellowship director in the Division of Maxillofacial Oncology and Reconstructive Surgery at John Peter Smith Health Network, told DTI. “Creating a 3D-printed dental prosthesis in-house allows more control for the surgeon to create the occlusal scheme. It is also much quicker. I can generate this prosthesis in one day, whereas dental laboratories can take two or more weeks,” he added. According to the researchers, outsourcing dental prostheses to a dental laboratory has previously created a delay in the treatment, which has limited its usefulness to benign condi- tions. In the present study, the digital workflow used allowed for immediate dental restoration for patients with malignant disease. “This time is significant for a patient with cancer waiting to get their surgery to remove their jaw and tumor,” Williams explained. Despite its clear advantages, the re- searchers believe that the digital workflow presented in the study is most suitable for patients with teeth in place pre- operatively that will be removed with their tumor. For more complex cases, it is necessary to familiarise oneself with image manipulation and prosthesis planning. Additionally, the researchers calculated that the total initial cost of a 3D printer and post-processing supplies can reach around $3,000.00, plus additional costs associated with using the software. Editorial note: The study, titled “Immediate teeth in fibulas: Planning and digital workflow with point-of-care 3D printing,” was published on 1 August 2020, in the Journal of Oral and Maxillofacial Surgery. m o c . k c o t s r e t t u h S / n k e k e e b © i l “The time required to generate the in-house 3D-printed prostheses was signifi cantly shorter when compared with dental laboratory-fabricated prostheses (...)” A recent study found that printing dental prostheses for fi bula and implant reconstructions in-house eliminates the additional waiting period before surgery, making the treatment suitable for patients with malignant disease. 3D printing 1 2021 09

possibility of same-day replacements and improved compatibility with fixed appliances for hybrid treatments. “The ability to provide aligners on the same day or even in the same week is huge. Our busy adult clientele love it,” Kaltschmidt explained. She said that integrating 3D print- ing is inevitable once a practice has begun using intra- oral scanners and that doing so has allowed Bellevue to take control of its workflow. “3D printing has allowed us to be in control of our own workflow, and with that, the possibilities are endless. We are able to provide aesthetic treatment options for our patients and keep the cost down by not accruing large laboratory fees from third-party companies. This includes in-house clear aligners, lingual braces and hy- brid treatment using a combination of both. 3D printing has truly changed the way we practice,” Kaltschmidt said. “We’re so used to next-day delivery with Amazon and other services, why should straightening teeth be any different?” Riolo asked in a press note. “Orthodontists have the technology and clinical expertise to expedite care in ways that major corporations cannot deliver. This is why we decided to adopt these technologies early on.” “The investment for orthodontists and dental profes- sionals to get started (with a 3D printer) can be any- where from $500 to $20,000 or more,” Kaltschmidt said. where from $500 to $20,000 or more,” Kaltschmidt said. where from $500 to $20,000 or more,” Kaltschmidt said. “Technology is advancing so quickly, and the cost of 3D “Technology is advancing so quickly, and the cost of 3D “Technology is advancing so quickly, and the cost of 3D printers will continue to come down. Our advice for those printers will continue to come down. Our advice for those printers will continue to come down. Our advice for those interested in getting started with 3D printing is to spend interested in getting started with 3D printing is to spend interested in getting started with 3D printing is to spend less on the printer and invest more time into refining your less on the printer and invest more time into refining your less on the printer and invest more time into refining your digital workflow. You will begin to notice the differences digital workflow. You will begin to notice the differences digital workflow. You will begin to notice the differences when you go from analog to digital.” when you go from analog to digital.” when you go from analog to digital.” l l l l l l l l l l m m m m m m m m m m o o o o o o o o o o c c c c c c c c c c . . . . . . . . . . k k k k k k k k k k c c c c c c c c c c o o o o o o o o o o t t t t t t t t t t s s s s s s s s s s r r r r r r r r r r e e e e e e e e e e t t t t t t t t t t t t t t t t t t t t u u u u u u u u u u h h h h h h h h h h S S S S S S S S S S / / / / / / / / / / n n n n n n n n n n k k k k k k k k k k e e e e e e e e e e k k k k k k k k k k e e e e e e e e e e e e e e e e e e e e b b b b b b b b b b © © © © © © © © © © i i i i i i i i i i “Orthodontists can definitely brand their own aligners and they absolutely should,” Kaltschmidt continued. “The product you design and manufacture in your office as an orthodontist is a superior product in the end, and you should package and brand your aligners to reflect that. In-house aligners give the practitioner full con- trol over workflow, time to delivery, trim line and choice of aligner materials.” Last year, Riolo and Kaltschmidt founded the Tooth Movement 3D-printing educational community in order to share their expertise on using 3D-printing technology for orthodontic applications like clear aligner therapy. Kaltschmidt said that demand from within the dental community for the limited courses on offer has been significant and that she and Riolo have worked mostly with orthodontists, members of the treatment team and recent graduates. “Many residents do not have any expo- sure to 3D printing while in their schooling,” she pointed out. industry news | Manufacturers are bullish on adoption of 3D printing in dentistry Advancements in 3D-printing technology have seen the quality of desktop models for dentistry climb while costs have fallen. According to Dr Baron Grutter, who owns a dental prac- tice in Kansas City, being able to offer clear aligner treat- ment at a lower cost has improved case acceptance at his practice for a product that is known for its high earn- ing potential. Grutter was an early adopter of 3D-printing technology in the dental practice and has manufactured his own clear aligners in-house for some time. He told the “Orthodontists have the technology and clinical expertise to expedite care in ways that major corporations cannot deliver”— Dr Christopher Riolo, Bellevue Orthodontics manufacturer SprintRay in its Practice Insights series last year that a return on the investment of a 3D-printing work- flow can be made by selling as few as three or four cases. Growing demand for this technology from dentists is being met by companies manufacturing solutions that are tailored to a number of dental applications, including making clear aligners. Manufacturers predict that sales will climb this year and that integrated digital workflows will make the technology even more accessible. Lee Kwang Min, vice president of the Korean 3D-printer manufacturer Carima, told the online trade journal 3D Printing Industry in 2019 “[2020] will be a full-scale dig- ital dentistry year. The emergence of a variety of 3D scan- ning solutions with an affordable price range, which has been an obstacle to the spread of digital dentistry, will re- place the milling machines in the market and, furthermore, (will accelerate) the rapid adoption of 3D printers.” Min said that he expects that a collaborative approach between individual manufacturers of 3D printers, software and scanners will act to increase the accessibility and adop- tion of the technology by dentists. 3D printing 1 2021 11

trends & applications | ment plan to the company’s technicians, who then create customised brackets and trays. The system uses ceramic material that is specially formulated for 3D printing, but which is otherwise virtually identical to that used in injection-molded brackets. The founder of the company, Dr Alfred Griffin III, told Dental Tribune International that the digital workflow resembles that used in clear aligner therapy. “LightPlan is the proprietary treatment software developed by LightForce that enables mass-customised braces,” he said. “Doctors have complete control over every aspect of the treatment plan and can utilise a simple cloud- based interface for adjustments and approvals.” “Our treatment plans are unique to each individual patient and largely follow the clear aligner workflow,” Griffin con- tinued. “Where our technology diverges is when the ortho- dontist uploads the patient’s scan to our LightPlan soft- ware, which enables the doctor to adjust the teeth virtually in order to create a perfect smile and bite for that unique patient, enabled by automatically designed braces.” Griffin explained that the LightPlan software generates bracket files, which are then printed at LightForce’s central- ised manufacturing plant in Cambridge. The brackets are then delivered to the orthodontist’s office about a month later. Increased personalisation using digital tools LightForce says that orthodontists should “move teeth, not brackets.” LightForce aims to provide treatment for malocclusion, which is as individual as each patient is. “A person’s lips, jaws, teeth and smile are individual, and it’s important to customise the tools that impact his or her face,” Griffin ex- plained. “3D printing provides the ideal solution for patients, as it allows for customisation and uses modern technology to address an age-old problem. We’ve found 3D printing to be the best solution for orthodontic applications because it enables complete personalisation for each patient—it can print complex geometries, in this case unique tooth mor- phology that would otherwise be unavailable to patients.” He added: “On the one hand, we believe that the days of bracket prescriptions are numbered; on the other hand, we welcome the days of ‘tooth prescriptions’ for mass-customised appliances like aligners and 3D-printed brackets that can adapt to achieve a desired final tooth position for that unique patient.” Griffin said that, in the future, he expects that there will be a rapid expansion of 3D-printing technology within the dental industry. LightForce Orthodontics was founded in 2015. Over the last five years, Griffin and his team have undertaken extensive research and development for what is now the company’s eponymous treatment platform. No one could have predicted that the 2020 launch of the bracket system would take place in the midst of a global pan- “Our treatment plans are unique to each individual patient and largely follow the clear aligner workflow.” demic, but it seems that the outbreak of SARS-CoV-2 has not hampered the company’s plans. “In light of the ongoing pandemic, technology that reduces in-person dental visits is crucial not only for patients but also for the orthodontists and their teams that are caring for them,” Griffin said. Hundreds of orthodontists throughout the US are already providing treatment using LightForce brackets. Griffin said that the company will use its newly acquired funds to fur- ther develop its technology and product offerings and to scale its operations in order to meet what he called a recent surge in demand for more efficient dental technologies. The funds were raised in a Series B funding round that was led by investors Tyche Partners, Matrix Partners and AM Ventures. 3D printing 1 2021 15

opinion | by high pressure or mixing with a catalyst. It is also known as Stereolithography, and commonly referred to as SLA. 2. Laser sintering with both for metals and thermoplas- tics is an Additive Manufacturing process that be- longs to the Powder Bed Fusion family. A laser selec- tively sinters the particles of a polymer powder, fusing them together and building a part, layer-by-layer. It is known as Selective Laser Sintering and commonly referred to a SLS or SLM. Laser sintering is very ex- pensive, with high maintenance costs, but delivers amazing results. 3. Extrusion is a 3D printing process that uses a contin- uous filament of a thermoplastic material. It is known as Fused Filament Fabrication or Fused Deposition Modeling and commonly referred to as FDM. This technology is based on feeding a modelling filament through a heated nozzle, and printing layer by layer. While very affordable, FDM’s accuracy and service quality are quite limited with respect to dental appli- cations. Various companies utilise differing photopolymerisation technology categories: 1. SLA—Stereolithography printing exposes the liquid resin to a laser light source. 2. LFS—Low Force Stereolithography can be described as SLA’s successor. It uses a flexible tank and linear illumination to polymerise liquid resin. 3. DLP—Digital Light Processing exposes the liquid resin to a DLP projector light source. 4. LED—New technology that uses LED instead of laser light sources for the additive manufacturing of metal parts and optimises 3D metal printing. However, the underlying principle is the same: a polymer- ising light hardens the resin to a solid-state layer by layer. DLP or LED techniques offer faster results, while SLA and LFS modes provide smoother and finer details, but the process is significantly slower. There are numerous dental applications for 3D printing.2 In fact, there are many applications that are not possible without 3D printing (aligner thermoforming models, indi- rect bonding trays). 3D printing can enhance traditional techniques such as surgical guides, custom impression trays, diagnostic models, splints, restorative models, and provisionals. And there are novel 3D printing opportunities such as full dentures and permanent indirect and direct restorations. In my daily practice I find many situations where 3D print- ing allows me to offer existing services more predictably and rapidly. Currently available options include: provi- sional crown and bridge restorations, inlays, onlays and veneers. The ability to print splints represents a tremendous ad- vantage; a reliable inhouse splint can be completed in a single appointment whereas sending the case to a dental laboratory is far less efficient and much more ex- pensive. The routine use of rapidly printed surgical guides improves the patient’s perception of surgical procedures, speeds treatment, and assists in predictable results for every case. 3D inhouse printing reduces the waiting time before surgeries.3 In the past, it was extremely difficult to treat totally eden- tulous patients with significant bone loss. Ultimately, the limitations of dentist–technician communications made the process long and tedious, and results were often less than satisfactory. It was also frustrating that during this time-consuming ordeal the patient had no access to pro- visional dentures. 3D printed full dentures, available the same day, offer a practical solution to both patient and dentist. Scanner, 3D printer and an in-house technician are the ideal. As with any new technology, 3D printing has a learn- ing curve. It is highly recommended that the practitioner begin with simpler procedures, and then tackle more complex ones as experience and confidence are accu- mulated. 3D printing technology is a game changer in the dental industry that will greatly influence and modify patient treatment in the years to come. 3D printing, taken together with CAD/CAM and CBCT, creates a comprehensive shift to digital dentistry, a trend that is rapidly redefining the dental profession. Editorial note: A list of references is available from the publisher. This article originally appeared in Oral Health Magazine, and an edited version is provided here with permission from Newcom Media. about Dr Florin Lăzărescu owns a private dental practice in Bucharest in Romania and in his work focuses on aesthetic dentistry with an emphasis on all-ceramic and implant restorative procedures. He is the author of numerous publications on dentistry, and he is the editor of and a contributing author to the Romanian book Incursiune în Estetică Dentara (Immersion in Esthetic Dentistry, Society of Esthetic Dentistry in Romania, 2013)— republished in English as Comprehensive Esthetic Dentistry (Quintessence, 2015) and in Chinese (Qiuntessence China, 2017). He is editor-in-chief of Dental Tribune Romanian Edition. Dr Lăzărescu is the president of the European Society of Cosmetic Dentistry and a founding member and director of the Society of Esthetic Dentistry in Romania. 3D printing 17 1 2021 17

case report | 6a 6b Figs. 6a & b: Two 3D-printed templates designed on the digitised model (green): one for the initial drill to section the tooth at the root apex (a) and the second for using sequential guided drills to drill through the root itself (b). “Triangle of Bone” concept and specific instrumentation to achieve successful outcomes.5 The ability to perform the procedures requires care- ful diagnosis, treatment planning and excellent control of the drilling process to ensure that the root fragment will be maintained while maximising implant stability. In many cases, it may also be possible to provide imme- diate transitional restorations when high implant stability is achieved. However, complications can also arise when the root fragment is lost or the implant fails to integrate. It should be noted that PET has mainly been accomplished with a diagnostic freehand method for sectioning roots, osteotomy preparation and implant placement. The cur- rent article describes methods of providing PET proce- dures using full-template guidance based on a thorough appreciation of the existing anatomical structures utilis- ing advanced state-of-the-art treatment planning tools, 3D design software, 3D printing and/or CAD/CAM sur- gical templates. 7a 8a 7b 8b Fig. 7a: A sleeveless guide to accommodate a 2 mm long pilot drill that was used to reach the root apex. Fig. 7b: Removing the guide allowed for inspection of the drill embedded within the tooth. Figs. 8a & b: Using drill guides with long shanks to engage the sleeveless template allowed for sequential and accurate drilling of the tooth and subsequent bone for implant placement. 3D printing 1 2021 19

case report | 15a 15b 15c Fig. 15a: The base template was designed to seat firmly on the adjacent teeth, incorporating buccal and lingual hexagonal offsets to engage the different drill guide inserts. Figs. 15b & c: Separate inserts were fabricated for the initial drill guide to reach the root apex to accommodate sectioning, followed by a second guide for final osteotomy drilling and implant placement. fully appreciate the trajectory through the clinical crown (Blue Sky Plan, Blue Sky Bio). It is important to visualise the root fragment that will remain in order to properly sim- ulate the position of the implant in the alveolus (Fig. 3b). The apical portion of the implant can be positioned to gain stability in host bone using the Triangle of Bone. It is important to note that a cross-sectional slice may only be 0.125 mm in thickness based on the CBCT ac- quisition, and therefore all images in all views must be visualised to confirm the plan. Utilising 3D segmentation (separating objects by density values), it is possible to define each root and further assess the simulated posi- tion of the implant with a sagittal cut through the 3D re- constructed volume (Fig. 4). The ability to export volumes in STL format allows these objects to be edited and utilised in other software appli- cations, such as Meshmixer (Autodesk). The STL file of the root image was imported into Meshmixer, and the root was virtually sectioned using Boolean difference to mimic the crescent shape for PET (Fig. 5a). The apical portion of the simulated implant can then be positioned so as not to touch the root fragment while engaging in host bone for stability (Fig. 5b). Planning with such precision is predicated on the acqui- sition of a satisfactory CBCT scan with a proper field of view and the incorporation of occlusal surface data STL files of the arch form, digitised through either an intra-oral scan or a desktop scanner imported into the software. Two 3D-printed templates were then designed on the accurate digitised surface model, one for the initial drill to section the tooth at the root apex and the second to use sequential guided drills to drill through the root itself (Fig. 6). A 2 mm pilot drill, which was long enough to reach the root apex with the tooth-borne surgical guide in place, was utilised with a sleeveless guided approach (Fig. 7a). Removing the guide allowed for inspection of the drill through the tooth (Fig. 7b). Using guided drills with long shanks in a sleeveless guide allowed for sequen- tial and accurate removal of the tooth and subsequent bone beyond the apex of the natural tooth root (R2Gate, MegaGen; Fig. 8). The cylindrical tooth preparation/oste- otomy resulted in the desired crescent shape to provide space for the implant (Fig. 9). The root was then sectioned mesiodistally using specialised drills (Root Membrane Kit, MegaGen) and the palatal section removed. Utilising 16a 16b Figs. 16a & b: The accuracy of the implant and template design allows for true restoratively driven planning combined with CAD/CAM applications for the design and fabrication of a patient-specific abutment and transitional restoration. 3D printing 1 2021 21

case report | 26a 26b 26c 26d Figs. 26a–d: The prefabricated CAD/CAM abutment and transitional crown (a). A post-op periapical radiograph confirmed successful sub-crestal placement of this platform-switched design (b). The abutment in place (c). The soft-tissue contours were excellent; no sutures were required for the transitional restoration (d). the template, the implant was placed into the osteotomy using the correct implant carrier to achieve full-template guidance and stability measured using resonance fre- quency analysis (RFA) to obtain the implant stability quo- tient (ISQ; Fig. 10). tooth-borne guide); (2) a pilot drill guide for the root apex (APEX STACK); (3) a crescent-shaped guide for shaping root fragments (PET Shaper STACK); and (4) a guide for osteotomy drilling and placing the implant through the guide (Surgical Guide STACK; Fig. 11). The concept of drilling through the root is not new and has been reported in the literature.8 Using guided meth- ods for the socket shield technique has also been re- ported using a CAD/CAM-fabricated template.9 However, the ability to use technology to plan and execute a fully guided procedure for a PET, socket shield technique and root membrane technique illustrates additional method- ology to aid clinicians in successful outcomes. The first concept described the use of two separate templates, one for separating the root at the apex and the second for drilling through the tooth and placing the implant. Continuing the evolution, we present a second option, which does not require the removal of the base template, but has inserts to allow for the different drills and angulation required for the PET technique: the stack- able tooth-borne guide. The new technique has four separate components: (1) a base template (stackable Case report A 62-year-old male patient presented with a hopeless prognosis for a post fracture in the left central incisor requiring extraction (Figs. 12a & b). The preoperative peri- apical radiograph revealed an existing implant support- ing a metal–ceramic restoration for the adjacent region #11 (Fig. 13). The CBCT (CS 9600, Carestream Dental) cross-sectional image revealed a favourable preoperative condition relating to the trajectory of the endodontically treated root to the alveolus for a PET procedure (Fig. 14a). Using the native Carestream 3D Imaging software, a simulated implant and abutment projection was posi- tioned within the available bone to avoid the root frag- ment (Fig. 14b). The final positioning of the implant, as determined by the restorative requirements, and design and fabrication of 27a 27b Figs. 27a & b: The post-op CBCT scan axial view revealed the intact crescent shape of the root membrane (a), as outlined in red in facial to the opaque implant position (b). 3D printing 1 2021 23

case report | (AnyRidge, MegaGen) was facilitated by the R2Gate surgical carrier for full-template guidance at the appropri- ate torque values (Fig. 23). Depth control and rotational positioning were accurately confirmed with the notch indicated on the template to correspond with the inser- tion tool (Fig. 24). The initial plan was for immediate extraction, immediate placement and immediate restoration. Therefore, it was essential to measure the implant’s stability with an objec- tive technology, RFA, which provides an ISQ value util- ising an implant-specific SmartPeg (Osstell; MEGA ISQ, MegaGen). The baseline ISQ value (76) confirmed suf- ficient initial stability to place an immediate restoration (Fig. 25). The prefabricated CAD/CAM abutment was then secured to the implant, and a postoperative peri- apical radiograph confirmed successful sub-crestal placement for this platform-switched design (Fig. 26a). The transitional acrylic restoration was then placed and examined for any occlusal interferences (Fig. 26b). It was important that the restoration be out of occlusion to avoid premature forces that could complicate inte- gration. The soft-tissue contours were excellent, and no sutures were required, since no flap was raised (Figs. 26c & d). After a period of eight weeks, the im- plant stability was measured to be at 80 ISQ, confirming that the integration process had continued to progress successfully and that the implant was ready for the de- finitive restoration. An intra-oral scanner and scanning abutment were then utilised to capture the position of the implant and soft-tissue emergence profile. The post - operative CBCT scan revealed the intact crescent shape of the root membrane (Figs. 27 & 28). The definitive restoration was then delivered and exhibited excellent retention of the soft-tissue profile (Figs. 29 & 30). Conclusion PET, root membrane and socket shield concepts have gained popularity as the techniques have been refined and their efficacy proved in published long-term stud- ies. The purpose of retaining the root is to maintain the periodontal ligament attachment to the bony walls of the socket in order to prevent subsequent resorption and loss of tissue volume which often occurs after tooth ex- traction. PET has been proved to preserve bundle bone and tissue volume with and without immediate implant placement, yet this minimally invasive treatment modal- ity is highly technique-sensitive and may result in com- plications if proper protocols are not followed. Therefore, a complete understanding of the 3D anatomical presen- tation is essential for preliminary diagnosis, treatment planning and execution of the procedure. The present article has described two alternatives that maximise the diagnostic phase using state-of-the-art CBCT imaging and planning software to provide full-template guidance with a new stackable tooth-borne guide with specific in- serts for the root preparation as well as the osteotomy preparation and delivery of the implant. As with most techniques, further clinical trials are recommended to provide additional long-term data to validate these treat- ment modalities. Acknowledgement: The authors would like to thank Dr Barry Kaplan of Morristown in New Jersey in the US for his expertise and assistance in the preparation of this article. Editorial note: This article originally appeared in Dentistry Today in September 2020, and an edited ver- sion is provided here with permission from Dentistry Today. A list of references is available from the publisher. about Dr Scott D. Ganz received his specialty certificate in maxillofacial prosthetics and prosthodontics, and this led to his focus on the surgical and restorative phases of implant dentistry and his subsequent contribution to 15 implant-related textbooks. He is a fellow of the Academy of Osseointegration, a diplomate of the International Congress of Oral Implantologists (ICOI), US ambassador of the Digital Dental Society, president of the US branch of the Digital Dentistry Society (DDS) and a co-director of Advanced Implant Education (AIE). Dr Ganz is on the teaching staff of the Rutgers School of Dental Medicine in Newark in New Jersey and maintains a private practice in Fort Lee in New Jersey. He can be reached at drganz@drganz.com. Dr Isaac Tawil sits on the Digital Dental USA Society Board of Directors, and is a diplomate of the International Academy of Dental Implantology, the IADFE, a fellow of the Advanced Dental Implant Academy, and the ICOI. He is one of Dentistry Today’s Top Leaders in CE, a faculty member of the Osseodensification Academy, Brighter Way educational director (Phoenix, Arizona), and digital director of Guided Smile. Dr Tawil is an ambassador of MegaGen International Network of Education and Clinical Research, a member of MINEC USA and an ambassador for the Slow Dentistry initiative. A recipient of the Pierre Fauchard award and the Presidential Service Award for outstanding achievements in dentistry. He is the founder and co-director of Advanced Implant Education, a partner in TBS instruments, and Universal Shapers LLC, and a new product consultant for dental industry. Dr Tawil has held main podium sessions and workshops globally and maintains a private practice in Brooklyn, New York. He can be reached at iketawil@mac.com. 3D printing 1 2021 25

industry | Fig. 2: Impact of COVID-19 on the 3D printer market in Asia Pacifi c. Trend #3: COVID-19’s impact on the Asia Pacifi c market The global dental market was significantly affected by the COVID-19 pandemic, and Asia Pacific was no exception. The markets for dental prosthetics as well as CAD/CAM devices and materials are interdependent and have, therefore, also been similarly affected. The overall mar- ket value for dental prosthetics decreased dramatically compared with the previous year because of the elective nature of the procedures and the tight regulations that led to the closure of many dental clinics. Owing to its high price point, the premium market was impacted the most notably. The total market is expected to recover in 2021 and continue to grow at a moderate pace. 3D dental printers market forecast Overall, the dental 3D printer market in Asia Pacific ex- perienced a decline in 2020 because of reduced dental spending across the nation. This decline is temporary, and the market will return to normal unit sales forecasts by 2022. For the remainder of the forecast period, the dental 3D printer market in Asia Pacific is expected to experience strong unit sales growth; as more labora- tories go digital and more CAD/CAM materials receive regulatory approval, the demand for 3D printers will increase. Sources: iData Research. 2021 China Market Report Suite for Digital Dentistry | MedSuite | With impact of COVID-19 (https://idataresearch.com/product/ digital-dentistry-market-china/) iData Research. 2021 India Market Report Suite for Digital Dentistry | MedSuite | With impact of COVID-19 (https://idataresearch.com/product/ india-digital-dentistry-market/) iData Research. 2021 Japan Market Report Suite for Digital Dentistry | MedSuite | With impact of COVID-19 (https://idataresearch.com/product/ japan-digital-dentistry-market/) iData Research. 2021 South Korea Market Report Suite for Digital Dentistry | MedSuite | With impact of COVID-19 (https://idataresearch.com/product/ digital-dentistry-market-south-korea/) iData Research. 2021 Australia Market Report Suite for Digital Dentistry | MedSuite | With impact of COVID-19 (https://idataresearch.com/product/ digital-dentistry-market-australia/) about Kiavash Bakrani is a senior research analyst at iData Research. He has been involved in the global research of dental prosthetics and digital dentistry markets, publishing the reports on the Asia Pacifi c market. Dr Kamran Zamanian is the CEO and founding partner of iData Research. He has spent over 20 years working in the market research industry with a dedication to the study of dental and medical devices used in the health of patients all over the globe. 3D printing 1 2021 27

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