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Application of 3D Printing in Production of Dental Instruments
Abstract
Traditionally, dental implants and surgical instruments are fabricated via conventional subtractive methods. 3D printing has some advantages over these subtractive methods by fabricating customized surgical instruments and patient-specific implants without material waste. It also allows the surgeon to easily modify the instruments and implants based on specific needs. The unique possibilities provided by 3D printing make this method a promising approach to manufacture general and patient-specific medical instruments. This chapter focuses on the application of 3D printing in the fabrication of dental instruments. Surgical guides, splints, oral and maxillofacial implants, dental implants, crowns and dentures, and total jaw prostheses have been considered separately. For each of the instrument types, related studies and the practical aspects have been presented and discussed.
... One of the primary benefits of 3D printing in dental prosthetics is its ability to deliver highly customized devices [40]. The process begins with digital scanning of the patient's oral structures, allowing for exact digital rep- licas of crowns, bridges, and dentures to be designed based on the patient's specific dental morphology [41]. ...
3D printing technology has introduced significant advancements in dentistry, particularly in the customization of dental prosthetics and orthodontic appliances. By enabling precise, patient-specific designs, 3D printing enhances both the fit and comfort of dental devices, improving patient outcomes and satisfaction. This technology offers notable efficiencies over traditional manufacturing methods, reducing production times and costs while supporting seamless digital workflows in clinical practice. Recent advancements in biocompatible materials and digital integration have expanded the application of 3D printing to a range of dental devices, from crowns and bridges to clear aligners and retainers. However, challenges remain, including material limitations, regulatory hurdles, and technical constraints that can impact adoption, particularly in smaller clinics. Future research aims to address these challenges by exploring new materials, incorporating artificial intelligence for optimized design, and enhancing environmental sustainability through waste reduction. The ongoing evolution of 3D printing in dentistry promises to further personalize and streamline dental care, paving the way for a more patient-centered, efficient, and accessible approach in modern dental practices.
Purpose
The three-dimensional (3D) printing method is a modern approach in which different custom designs are fabricated with high complexity according to the patient’s need. This narrative review aimed to highlight the materials used in 3D printers for medical use, especially in the field of oral and maxillofacial surgery.
Methods
PubMed, Web of Sciences, and Google Scholar were searched for the relevant studies, and after meeting the inclusion criteria, articles were studied, and focused points were highlighted.
Results
s: Synthetic and natural materials used in 3D printing include hydroxyapatite, tricalcium phosphate, bicalcium phosphate, apatite–wollastonite glass ceramics, stem cells, and collagen. The most frequent clinical applications include dental implants, maxillofacial trauma, facial cosmetics, orthognathic surgery, maxillofacial oncology, and maxillofacial reconstruction. Anatomical models and surgical instructions were the most often printed objects. The key benefits were increased surgical precision and a shorter operating time. The cost of the items, the length of the manufacturing process when printed by the industry, and legal concerns were the main drawbacks.
Conclusion
The 3D models are beneficial for surgeons as they can save time and even human life. In the future, additional research should be done on the modeling, efficacy, and safety of natural materials, and systematic reviews and meta-analyses should be conducted for a better understanding.
Purpose:
To present the application of custom-made 3D-printed subperiosteal implants for fixed prosthetic restoration of the atrophic posterior mandible of elderly patients.
Methods:
Between January 2017 and June 2018, all partially edentulous patients aged over 65 years, with two or more missing teeth in the posterior atrophic mandible, and who did not want to undergo bone regenerative procedures, were included in this study. These patients were rehabilitated with custom-made subperiosteal implants, designed from cone beam computed tomography (CBCT) and fabricated in titanium by means of direct metal laser sintering (DMLS). The outcome measures were fit and stability of the implants at placement, duration of the intervention, implant survival, and early and late complications. All patients were followed for 1 year after surgery.
Results:
Ten patients (four males, six females; mean age 69.6, SD ± 2.8, median 69, 95% CI 67.9-71.6) were included in the study. The fit of the implants was satisfactory, with a mean rating of 7 out of 10 (SD ± 1.6, median 7, 95% CI 6-8). Only two implants had insufficient fit, because of the presence of scattering in the CBCT; however, they were adapted to the sites during the interventions. The mean duration of the intervention was 44.3 min (SD ± 19.4, median 37, 95% CI 32.3-56.3). At the one-year follow-up, no implants were lost (survival rate 100%). One implant presented immediate postoperative complications with pain, discomfort and swelling, and two patients experienced late complications, having their provisional restorations fractured during the temporisation phase. All these complications were minor in nature, but the final complication rate amounted to 30% (three of ten patients).
Conclusions:
Although this study has limits (small patient sample and short follow-up), DMLS has proven to be an effective method for fabricating accurate subperiosteal implants, with high survival rates. This may represent an alternative treatment procedure in elderly patients with a severely atrophic posterior mandible, since it allows avoidance of regenerative bone therapies. Further studies are needed to confirm these outcomes.
Purpose
To present a digital technique for the fabrication of custom-made subperiosteal implants and to report on the survival and complication rates encountered when using these fixtures.
Methods
The data used for this retrospective clinical study were derived from the medical records of five different private dental practices. Inclusion criteria were patients over the age of 60, treated with custom-made direct metal laser sintering (DMLS) titanium subperiosteal implants (Eagle-Grid®, BTK, Dueville, Vicenza) during a two-year period (2014-2015) and restored with fixed restorations; all enrolled patients needed to have complete pre- and postoperative clinical and radiographic documentation, with at least 2 years of follow-up. Exclusion criteria were smoking and bruxism. The main outcomes looked at were implant survival and complications.
Results
Seventy patients (39 males and 31 females, aged 62-79 years) who had been treated with custom-made DMLS titanium subperiosteal implants were enrolled in this study. After 2 years of follow-up, three implants were lost due to recurrent, untreatable infections; the survival rate was therefore 95.8% (67/70 implants). Four patients reported pain/discomfort/swelling after implant placement; the incidence of immediate postoperative complications was therefore 5.7% (4/70 implants). During the follow-up period, one patient suffered from recurrent infections classified as a biologic complication; the incidence of biologic complications was therefore 1.4% (1/67 surviving implants). Finally, four patients experienced prosthetic problems with their implant-supported restorations during the provisional phase (fracture of the acrylic restoration) and two patients had ceramic chipping of the definitive restoration; the incidence of prosthetic complications was therefore 8.9% (6/67 surviving implants).
Conclusions
Within the limits of the present study (limited follow-up time and low number of patients treated, retrospective design), the application of custom-made DMLS titanium subperiosteal implants showed satisfactory implant survival (95.8%) and low complication rates. Further studies are needed to confirm the positive outcomes found in this research.
The aim of this study was to assess two new protocols for single-stage rehabilitation of the severely atrophic maxillary ridge using customized porous titanium or polyether ether ketone (PEEK) sub-periosteal implants. Ten patients with a severely atrophic anterior maxillary alveolar ridge were divided randomly into two groups (five patients in each) to receive customized sub-periosteal implants fabricated via CAD/CAM technology: group 1, porous titanium implants; group 2, PEEK implants. Prosthetic loading with fixed acrylic bridges was performed 1 month postoperative. The implants were followed-up for 12 months and evaluated for the presence of any sign of radiographic bone resorption, mobility, infection, prosthetic fracture, or implant exposure. The immediate postoperative period was uneventful except for one case complicated by wound dehiscence in group 1. At 12 months, all implants were functionally stable and the patients were comfortable with the prostheses. No signs of radiographic bone resorption, mobility, infection, or prosthetic fracture were observed. Within the limitations of this study, the application of customized porous titanium and PEEK sub-periosteal implants produced through CAD/CAM technology appears to be an acceptable method for single-stage prosthetic rehabilitation of the severely atrophic edentulous anterior maxilla. This study was awarded the best case study at the academy of osseintegration annual meeting 2017, Orlando, Florida.
Guided surgery is accepted as the most accurate way to place an implant and predictably relate the implant to its definitive prosthesis, although few clinicians use it. However, recent developments in high-quality desktop 3-dimensional stereolithographic printers have led to the in-office fabrication of stereolithographic surgical guides at reduced cost. This clinical report demonstrates a protocol for using a cost-effective, in-office rapid prototyping technique to fabricate a surgical guide for dental implant placement.
Statement of problem:
The fit of interim crowns fabricated using 3-dimensional (3D) printing is unknown.
Purpose:
The purpose of this in vitro study was to evaluate the fit of interim crowns fabricated using photopolymer-jetting 3D printing and to compare it with that of milling and compression molding methods.
Material and methods:
Twelve study models were fabricated by making an impression of a metal master model of the mandibular first molar. On each study model, interim crowns (N=36) were fabricated using compression molding (molding group, n=12), milling (milling group, n=12), and 3D polymer-jetting methods. The crowns were prepared as follows: molding group, overimpression technique; milling group, a 5-axis dental milling machine; and polymer-jetting group using a 3D printer. The fit of interim crowns was evaluated in the proximal, marginal, internal axial, and internal occlusal regions by using the image-superimposition and silicone-replica techniques. The Mann-Whitney U test and Kruskal-Wallis tests were used to compare the results among groups (α=.05).
Results:
Compared with the molding group, the milling and polymer-jetting groups showed more accurate results in the proximal and marginal regions (P<.001). In the axial regions, even though the mean discrepancy was smallest in the molding group, the data showed large deviations. In the occlusal region, the polymer-jetting group was the most accurate, and compared with the other groups, the milling group showed larger internal discrepancies (P<.001).
Conclusions:
Polymer-jet 3D printing significantly enhanced the fit of interim crowns, particularly in the occlusal region.
Objectives:
This study aimed to explore the feasibility of fabrication of three-dimensional (3D)-printed zirconia root analogue implant (RAI) through digital light processing (DLP) technology.
Material and methods:
One partially edentulous mandibular human cadaver was scanned with a cone-beam computed tomography (CBCT) system. The scan volumes and data sets were used to create computer-aided design (CAD) model of the RAI. A high-end DLP 3D printing technology was used to fabricate the RAI from the CAD model. Within this approach, solid 3D objects are built using a DLP projector to translate voxel data so it is reproduced in liquid photopolymer dispersed with a commercial ceramic, thereby light polymerizing the resin to solid. Optical scanning technology was used to measure the tooth and 3D-printed RAI. To validate the accuracy of the printed zirconia RAI, the optical surface model of the original tooth and CAD model were superimposed.
Results:
The differences between the optical scans of the RAI and original tooth are most noticeable towards the apical foramen, showing a disparity for the RAI with a maximum deviation of 0.86 mm. When setting a maximum threshold of 0.5 mm for the 3D-printed RAI surface to be deviating from the original tooth model and CAD model, measurements show 1.55% and 4.86% of the surface areas are exceeding the threshold distance, respectively.
Conclusion:
With the use of currently available technology, it is well feasible to 3D print in zirconia a custom RAI.
Statement of Problem. Direct metal laser sintering (DMLS) is a technology that allows fabrication of complex-shaped objects from powder-based materials, according to a three-dimensional (3D) computer model. With DMLS, it is possible to fabricate titanium dental implants with an inherently porous surface, a key property required of implantation devices. Objective. The aim of this review was to evaluate the evidence for the reliability of DMLS titanium dental implants and their clinical and histologic/histomorphometric outcomes, as well as their mechanical properties. Materials and Methods. Electronic database searches were performed. Inclusion criteria were clinical and radiographic studies, histologic/histomorphometric studies in humans and animals, mechanical evaluations, and in vitro cell culture studies on DMLS titanium implants. Meta-analysis could be performed only for randomized controlled trials (RCTs); to evaluate the methodological quality of observational human studies, the Newcastle-Ottawa scale (NOS) was used. Results. Twenty-seven studies were included in this review. No RCTs were found, and meta-analysis could not be performed. The outcomes of observational human studies were assessed using the NOS: these studies showed medium methodological quality. Conclusions. Several studies have demonstrated the potential for the use of DMLS titanium implants. However, further studies that demonstrate the benefits of DMLS implants over conventional implants are needed.
Background
The occurrence of mandibular defects caused by tumors has been continuously increasing in China in recent years. Conversely, results of the repair of mandibular defects affect the recovery of oral function and patient appearance, and the requirements for accuracy and high surgical quality must be more stringent. Digital techniques — including model reconstruction based on medical images, computer-aided design, and additive manufacturing — have been widely used in modern medicine to improve the accuracy and quality of diagnosis and surgery. However, some special software platforms and services from international companies are not always available for most of researchers and surgeons because they are expensive and time-consuming.
Methods
Here, a new technical solution for guided surgery for the repair of mandibular defects is proposed, based on general popular tools in medical image processing, 3D (3 dimension) model reconstruction, digital design, and fabrication via 3D printing. First, CT (computerized tomography) images are processed to reconstruct the 3D model of the mandible and fibular bone. The defect area is then replaced by healthy contralateral bone to create the repair model. With the repair model as reference, the graft shape and cutline are designed on fibular bone, as is the guide for cutting and shaping. The physical model, fabricated via 3D printing, including surgical guide, the original model, and the repair model, can be used to preform a titanium locking plate, as well as to design and verify the surgical plan and guide. In clinics, surgeons can operate with the help of the surgical guide and preformed plate to realize the predesigned surgical plan.
Results
With sufficient communication between engineers and surgeons, an optimal surgical plan can be designed via some common software platforms but needs to be translated to the clinic. Based on customized models and tools, including three surgical guides, preformed titanium plate for fixation, and physical models of the mandible, grafts for defect repair can be cut from fibular bone, shaped with high accuracy during surgery, and fixed with a well-fitting preformed locking plate, so that the predesigned plan can be performed in the clinic and the oral function and appearance of the patient are recovered. This method requires 20% less operating time compared with conventional surgery, and the advantages in cost and convenience are significant compared with those of existing commercial services in China.
Conclusions
This comparison between two groups of cases illustrates that, with the proposed method, the accuracy of mandibular defect repair surgery is increased significantly and is less time-consuming, and patients are satisfied with both the recovery of oral function and their appearance. Until now, more than 15 cases have been treated with the proposed methods, so their feasibility and validity have been verified.
Background
Within the domain of craniomaxillofacial surgery, orthognathic surgery is a special field dedicated to the correction of dentofacial anomalies resulting from skeletal malocclusion. Generally, in such cases, an interdisciplinary orthodontic and surgical treatment approach is required. After initial orthodontic alignment of the dental arches, skeletal discrepancies of the jaws can be corrected by distinct surgical strategies and procedures in order to achieve correct occlusal relations, as well as facial balance and harmony within individualized treatment concepts. To transfer the preoperative surgical planning and reposition the mobilized dental arches with optimal occlusal relations, surgical splints are typically used. For this purpose, different strategies have been described which use one or more splints. Traditionally, these splints are manufactured by a dental technician based on patient-specific dental casts; however, computer-assisted technologies have gained increasing importance with respect to preoperative planning and its subsequent surgical transfer.
Methods
: In a pilot study of 10 patients undergoing orthognathic corrections by a one-splint strategy, two final occlusal splints were produced for each patient and compared with respect to their clinical usability. One splint was manufactured in the traditional way by a dental technician according to the preoperative surgical planning. After performing a CBCT scan of the patient’s dental casts, a second splint was designed virtually by an engineer and surgeon working together, according to the desired final occlusion. For this purpose, RapidSplint®, a custom-made software platform, was used. After post-processing and conversion of the datasets into .stl files, the splints were fabricated by the PolyJet procedure using photo polymerization. During surgery, both splints were inserted after mobilization of the dental arches then compared with respect to their clinical usability according to the occlusal fitting.
Results
Using the workflow described above, virtual splints could be designed and manufactured for all patients in this pilot study. Eight of 10 virtual splints could be used clinically to achieve and maintain final occlusion after orthognathic surgery. In two cases virtual splints were not usable due to insufficient occlusal fitting, and even two of the traditional splints were not clinically usable. In five patients where both types of splints were available, their occlusal fitting was assessed as being equivalent, and in one case the virtual splint showed even better occlusal fitting than the traditional splint. In one case where no traditional splint was available, the virtual splint proved to be helpful in achieving the final occlusion.
Conclusions
In this pilot study it was demonstrated that clinically usable splints for orthognathic surgery can be produced by computer-assisted technology. Virtual splint design was realized by RapidSplint®, an in-house software platform which might contribute in future to shorten preoperative workflows for the production of orthognathic surgical splints.
Purpose:
This article describes the preliminary findings of the mechanical properties of functionally graded titanium with controlled distribution of porosity and a reduced Young's modulus on the basis of a computeraided design (CAD) file, using the rapid-prototyping, direct metal laser sintering (DMLS) technique.
Materials and methods:
Sixty specimens of Ti-6Al-4V were created using a DMLS machine (M270) following the standard for tensile testing of metals. One group was fabricated with only 170 W of laser energy to create fully dense specimens (control group). The remaining specimens all featured an outer fully dense "skin" layer and a partially sintered porous inner "core" region. The outer "skin" of each specimen was scanned at 170 W and set at a thickness of 0.35, 1.00, or 1.50 mm for different specimen groups. The inner "core" of each specimen was scanned at a lower laser power (43 or 85 W).
Results:
The partially sintered core was clearly visible in all specimens, with somewhat greater porosity with the lower laser power. However, the amount of porosity in the core region was not related to the laser power alone; thinner skin layers resulted in higher porosity for the same power values in the core structure. The lowest Young's modulus achieved, 35 GPa, is close to that of bone and was achieved with a laser power of 43 W and a skin thickness of 0.35 mm, producing a core that comprised 74% of the total volume.
Conclusion:
Additive manufacturing technology may provide an efficient alternative way to fabricate customized dental implants based on a CAD file with a functionally graded structure that may minimize stress shielding and improve the long-term performance of dental implants.
Background:
Modern cone beam computed tomography (CBCT) acquisition and three-dimensional (3D) image processing, combined with direct metal laser sintering (DMLS), allows custom-made, root-analogue implants (RAIs).
Purpose:
To demonstrate how DMLS permits customized titanium RAI production, with immediate insertion and restoration in a fresh extraction socket of the anterior maxilla.
Materials and methods:
A titanium RAI perfect copy of the radicular unit needed for replacement was created by customized DMLS, and inserted into a fresh extraction socket of the esthetic area of the anterior maxilla.
Results:
Follow-up after 1 year: the DMLS RAI implant showed a satisfactory functional and esthetic integration, with no bone resorption or soft tissue recessions.
Conclusions:
The production of customized DMLS RAIs opens new interesting perspectives for immediate implantation.
Key words:
Direct metal laser sintering, Root analogue implant.
Statement of problem:
Placement of dental implants depends, among other factors, on anatomic conditions such as sufficient bone height and thickness. Thus, individualized dental implants seem to offer benefits for patients with alveolar bone resorption. Additive manufacturing has allowed for the fabrication of custom implants with microscale resolution and, although the efficiency of the process is unclear, is a potential process for manufacturing dental implants.
Purpose:
The purpose of this systematic review was to evaluate the current situation of additive manufacturing techniques for fabricating dental implants.
Material and methods:
An electronic search was performed in the databases PubMed, Lilacs, Cochrane Library, and Science Direct, with the terms "additive manufacturing" AND "dental implants," "rapid prototyping" AND "dental implants," "3 D printing" AND "dental implants," "electron beam melting" AND "dental implants," "selective laser melting" AND "dental implants." The articles were screened, and the final selection of articles was obtained by using the inclusion and exclusion criteria.
Results:
The database search resulted in 1322 articles, which were screened for title and/or summary according to the inclusion criteria. From the selected 38 articles, 30 remained after applying the exclusion criteria. These were read completely, resulting in a selection of 13 articles for this systematic review. Owing to the great variety of articles with different objectives, the results were based on a descriptive analysis of the following topics: additive manufacturing technique and material, printed structure and implant design, implant characteristics, mechanical analysis, surface treatment, and osseointegration.
Conclusions:
Additive manufacturing is a new technology that may solve many problems in diverse fields. In dentistry, however, further studies are needed to improve the method for manufacturing custom dental implants because no standard methodology is available. Moreover, the advantages and disadvantages of the process are not yet clearly defined.
This dental technique describes a fully digital method for fabricating occlusal devices using a complete-arch intraoral scan and 3D printing. The maxillary and mandibular arches of a healthy, fully dentate volunteer were digitized using an intraoral scanner. A second scan and modified recording of the centric relation enabled a virtual arrangement of the maxillary and mandibular arches, both in centric relation and in the desired vertical dimension of occlusion. An occlusal device was subsequently designed virtually and fabricated from a light-polymerizing acrylic resin using a 3D printer. The occlusal device was tested for fit, occlusion, and patient-friendly handling. As only minor occlusal corrections were required, the fully digital procedure described is suitable for the fabrication of occlusal devices. © 2018 Editorial Council for the Journal of Prosthetic Dentistry
Statement of problem:
The primary manufacturing method of zirconia ceramic crowns is computer-aided design and computer-aided manufacture (CAD-CAM), but a disadvantage of this technique is material waste. Three-dimensional (3D) printing, which has been recently introduced into dentistry, has improved the processing of polymers and metals, but not yet of ceramic crowns.
Purpose:
The purpose of this in vitro study was to evaluate the 3D trueness of zirconia crowns fabricated by 3D printing to investigate the potential application of this technology in dental ceramic restorations.
Material and methods:
A typodont tooth was prepared for a ceramic crown, and a digital crown was designed using the CAD software. The digital crown was processed either with a 3D-printing system or with a dental milling system. The crowns were scanned using a dental laboratory scanner, and the data collected for each crown were divided into 4 parts (the external surface, intaglio surface, marginal area, and intaglio occlusal surface). Finally, the trueness of each part was determined using the 3D inspection software. The 3D trueness of the crowns fabricated by either 3D printing or milling was compared by a 1-sided test (α=.05).
Results:
The trueness of the external surface, intaglio surface, marginal area, and intaglio occlusal surface of the 3D-printed crowns was no worse than the corresponding trueness of the CAD-CAM crowns (P<.05).
Conclusions:
Zirconia crowns produced by 3D printing meet the trueness requirements, and 3D printing may be suitable for fabricating zirconia crowns.
Purpose:
The aim of this study is to present the preliminary clinical data on the OMX Temporomandibular Joint (TMJ) Prosthetic total joint replacement system.
Materials and methods:
A prospective, cohort, clinical study was undertaken of consecutive adult patients with Category 5 end-stage joint disease who were implanted with the OMX TMJ prosthesis between May 2015 and April 2017. A total of 50 devices were implanted in 38 patients, with 12 patients receiving bilateral prosthetic joints. There were 31 females and 7 males in this cohort, who ranged in age from 20 to 66 years, with a mean of 43.8 years (±14.0 years). Ten of the 50 prosthetic joints (20%) were fully customized, while the remaining were patient matched using virtual planning software.
Results:
Based on a mean follow-up period of 15.3 months (range 12-24 months) following the TMJ total joint replacement, preliminary results suggest the OMX TMJ prosthesis has made a positive impact on clinical outcomes, with a mean 74.4% reduction in joint pain levels and significant improvements (p < 0.05) in jaw function as measured by the visual analogue scales for mouth opening (30.8%), diet (77.1%), and function (59.2%). No device failures were reported during the study period.
Conclusion:
This study suggests that the print-on-demand OMX TMJ prosthesis, designed for rapid delivery of both patient-matched and fully customize devices, represents a safe, reliable and versatile implantable joint replacement system for the treatment of category 5 end-stage TMJ disease.
Introduction
Great precision is required for craniofacial surgery, and computer-aided design (CAD) methods may be used to plan surgery before it is performed. In this study, three-dimensional (3D)-printed cutting guides are used to match computer models with surgical procedures. We describe a novel method of computer-aided surgery for autologous cranioplasty that includes a new strategy for generating and using cutting guides. These guides may be used not only for osteotomies, but also for many other steps in the surgical procedure.
Materials and Methods
Preoperatively, anatomical data were imported into a CAD package and used for virtual surgical planning (VSP). Cutting guides were designed after considering how to integrate all the surgical steps. Models of the microplates and micro-screws were also made. Surgical guides were exported and printed, and preoperative simulations using a replica of the patient’s skull established the sequence of steps. The accuracy of the procedure was evaluated postoperatively using computed tomography (CT) scans.
Results
In every patient examined, the all-in-one surgical-guide system was able to automate the many steps in the procedure and dramatically decreased the duration of surgery. The experimental guide enhanced every phase of surgery, including excising the lesion, and harvesting, positioning, and fixing the graft. In each step, precision was enhanced and the outcome corresponded with the VSP.
Conclusions
The few previous reports on cutting guides used in cranioplasty generally describe the use of separate guides for dismantling and reconstruction. The ability to perform more surgical sequences using a single tool can improve surgical accuracy. Clearly there is no single perfect surgical guide; however, effective surgical-design strategies should be used to build the best approach to each procedure.
Purpose:
The aim of this study was to evaluate the dimensional accuracy, surface topography of a custom designed, 3D-printed zirconia dental implant and the mechanical properties of printed zirconia discs.
Materials and methods:
A custom designed implant was 3D-printed in zirconia using digital light processing technique (DLP). The dimensional accuracy was assessed using the digital-subtraction technique. The mechanical properties were evaluated using biaxial flexure strength test. Three different build angles were adopted to print the specimens for the mechanical test; 0°(Vertical), 45° (Oblique) and 90°(Horizontal) angles. The surface topography, crystallographic phase structure and surface roughness were evaluated using scanning electron microscopy analysis (SEM), X-ray diffractometer and confocal microscopy respectively.
Results:
The printed implant was dimensionally accurate with a root mean square (RMSE) value of 0.1mm. The Weibull analysis revealed a statistically significant higher characteristic strength (1006.6MPa) of 0° printed specimens compared to the other two groups and no significant difference between 45° (892.2MPa) and 90° (866.7MPa) build angles. SEM analysis revealed cracks, micro-porosities and interconnected pores ranging in size from 196nm to 3.3µm. The mean Ra (arithmetic mean roughness) value of 1.59µm (±0.41) and Rq (root mean squared roughness) value of 1.94µm (±0.47) was found. A crystallographic phase of primarily tetragonal zirconia typical of sintered Yttria tetragonal stabilized zirconia (Y-TZP) was detected.
Conclusions:
DLP prove to be efficient for printing customized zirconia dental implants with sufficient dimensional accuracy. The mechanical properties showed flexure strength close to those of conventionally produced ceramics. Optimization of the 3D-printing process parameters is still needed to improve the microstructure of the printed objects.
Introduction:
3D-printing seems to have more and more applications in maxillofacial surgery (MFS), particularly since the release on the market of general use 3D-printers several years ago. The aim of our study was to answer 4 questions: 1. Who uses 3D printing in MFS and is it routine or not? 2. What are the main clinical indications for 3D-printing in MFS and what are the kinds of objects that are used? 3. Are these objects printed by an official medical device (MD) manufacturer or made directly within the department or the lab? 4. What are the advantages and drawbacks?
Methodology:
Two bibliographic researches were conducted on January the 1(st), 2017 in PubMed, without time limitation, using "maxillofacial surgery" AND "3D printing" for the first and for the second "maxillofacial surgery" AND "computer-aided design" AND "computer-aided manufacturing" as keywords. Articles in English or French dealing with human clinical use of 3D printing were selected. Publication date, nationality of the authors, number of patients treated, clinical indication(s), type of printed object(s), type of printing (lab/hospital-made or professional/industry) and advantages/drawbacks were recorded.
Results:
297 articles from 35 countries met the criteria. The most represented country was the People's Republic of China (16% of the articles). A total of 2,889 patients (10 per article on average) benefited from 3D-printed objects. The most frequent clinical indications were dental implant surgery and mandibular reconstruction. The most frequently printed objects were surgical guides and anatomic models. 45% of the prints were professional. The main advantages were improvement in precision and reduction of surgical time. The main disadvantages were the cost of the objects and the manufacturing period when printed by the industry.
Discussion:
The arrival on the market of low-cost printers has increased the use of 3D-printing in MFS. Anatomic models are not considered to be MDs and do not have to follow any regulation. Nowadays they are easily printed with low-cost printers. They allow for better preoperative planning and training for the procedures and for pre-shaping of plates. Occlusal splints and surgical guides are intended for the smooth transfer of planning to the operating room. They are considered to be MDs and even if they are easy to print, they have to follow the regulations applying to MDs. Patient specific implants (custom-made plates and skeletal reconstruction modules) are much more demanding objects and their manufacturing remains nowadays in the hands of the industry. The main limitation of in-hospital 3D-printing is the restrictive regulations applying to MDs. The main limitations of professional 3D-printing are the cost and the lead time. 3D-printed objects are nowadays easily available in MFS. However, they will never replace a surgeon's skill and should only be considered as useful tools.
Personalized prosthetic joint replacements have important applications in cases of complex bone and joint conditions where the shape and size of off-the-shelf components may not be adequate. The objective of this study was to design, test and fabricate a personalized 3D-printed prosthesis for a patient requiring total joint replacement surgery of the temporomandibular joint (TMJ). The new ‘Melbourne’ prosthetic TMJ design featured a condylar component sized specifically to the patient and fixation screw positions that avoid potential intra-operative damage to the mandibular nerve. The Melbourne prosthetic TMJ was developed for a 58-year-old female recipient with end-stage osteoarthritis of the TMJ. The load response of the prosthesis during chewing and a maximum-force bite was quantified using a personalised musculoskeletal model of the patient's masticatory system developed using medical images. The simulations were then repeated after implantation of the Biomet Microfixation prosthetic TMJ, an established stock device. The maximum condylar stresses, screw stress and mandibular stress at the screw-bone interface were lower in the Melbourne prosthetic TMJ (259.6 MPa, 312.9 MPa and 198.4 MPa, respectively) than those in the Biomet Microfixation device (284.0 MPa, 416.0 MPa and 262.2 MPa, respectively) during the maximum-force bite, with similar trends also observed during the chewing bite. After trialing surgical placement and evaluating prosthetic TMJ stability using cadaveric specimens, the prosthesis was fabricated using 3D printing, sterilized, and implanted into the female recipient. Six months post-operatively, the prosthesis recipient had a normal jaw opening distance (40.0 mm), with no complications identified. The new design features and immediate load response of the Melbourne prosthetic TMJ suggests that it may provide improved clinical and biomechanical joint function compared to the stock device, and reduce risk of intra-operative nerve damage during placement. The framework presented may be useful for designing and testing a range of customized devices for the treatment of debilitating bone and joint conditions.
Orthognathic surgery is indicated for the treatment of significant skeletal malocclusion and is normally prepared using conventional face bows combined with two-dimensional cephalometric analysis and manually made splints. With recent developments in oral imaging, more orthognathic surgeries are being planned using three-dimensional computer-aided design and manufacturing (3D CAD/CAM) software. The purpose of this study was to present a protocol for the design and 3D printing of final digital occlusal splints based on 3D planning of orthognathic surgery and to validate the accuracy of these splints. The 3D virtual planning was performed in PROPLAN software (Materialise). The required data were then exported into 3-matic software (Materialise) to design the splints, which were 3D printed in biocompatible material using an Objet Connex 350 printer (Stratasys). To validate the accuracy of the splints, the cases of 20 patients undergoing orthognathic surgery were analysed. The splints were assessed clinically and quantitatively by comparing the printed splints to the conventional analogue set-up (clinical standard) and recording the absolute distance errors of three landmarks. The mean absolute distance error was 0.4. mm (standard deviation 0.17. mm), which falls within clinically accepted error margins. The absolute distance error ranged from 0.12 to 0.88. mm. © 2016 International Association of Oral and Maxillofacial Surgeons.
The use of virtual surgery, patient-specific saw and drill guides, and custom-made osteosynthesis plates is rapidly spreading from deformity surgery to orthognathic surgery. Most of the commercially available systems are using computer-aided design/computer-aided manufacture (CAD/CAM) wafers to produce patient-specific saw guides. However, most plate systems provided are still the conventional ?in stock? mini plates that can be individually designed by pre-bending according to the stereolithographic model of the patient. Custom made three-dimensional (3D) printed implants have earlier been demonstrated to be an ideal solution in deformity surgery and in reconstruction of complex posttraumatic cases. In this study, we report the novel use of patient-specific saw and drill guides combined with patient-specific 3D titanium alloy implants as a fixation system in maxillary movement after Le Fort I and bimaxillary osteotomies (n = 32). The implants were individually designed for each patient to follow anatomical structures and to provide exact positioning and stability of the repositioned maxilla.
Purpose:
The aim of the present study was to evaluate the effect of the build angle and the support configuration (thick versus thin support) on the dimensional accuracy of 3D-printed full-coverage dental restorations.
Materials and methods:
A full-coverage dental crown was digitally designed and 3D-printed using stereolithography-additive manufacturing (SLA-AM) technology. Nine different angles were used during the build process: 90, 120, 135, 150, 180, 210, 225, 240, and 270 degrees. In each angle, the crown was printed using a thin and a thick support type, resulting in 18 specimens. The specimens were digitally scanned using a high resolution optical surface scanner (IScan D104i; Imetric 3D). The dimensional accuracy was evaluated by digital subtraction technique. The 3D digital files of the scanned printed crowns (test model), exported in standard tessellation language (STL) format, were superimposed with the STL file of the designed crown (reference model) using Geomagic Studio 2014 (3D Systems).
Results:
The root mean square estimate value and color map results suggest that the build angle and support structure configuration have an influence on the dimensional accuracy of 3D-printed crown restorations. Among the tested angles, the 120-degree build angle showed a minimal deviation of 0.029 mm for thin support and 0.031 mm for thick support, indicating an accurate fit between the test and reference models. Furthermore, the deviation pattern observed in the color map was homogenously distributed and located further away from the critical marginal area.
Conclusions:
Within the limitations of this study, the selection of build angle should offer the crown the highest dimensional accuracy and self-supported geometry. This allows for the smallest necessary support surface area and decreases the time needed for finishing and polishing. These properties were mostly observed with a build angle of 120 degrees combined with a thin support type.
Introduction:
Virtual planning and guided surgery (VPGS) has been recently developed for mandibular reconstruction, but benefit remains to be assessed. The aim of this study was to analyze the impact of VPGS on operative time and postoperative course.
Material and methods:
All patients who underwent fibula free-flap mandibular reconstruction between 2013 and 2014 in our institution were included in a retrospective study. Operative times and postoperative course were compared between patients who underwent conventional surgery in 2013 and those who underwent VPGS in 2014.
Results:
A total of 29 patients were included: 11 in 2013 and 18 in 2014. Taking all types of mandibular defect together, ischemia time was significantly decreased by VPGS (75min, vs 150min for conventional surgery; P<0.001), whereas overall operative time was not significantly reduced (481 and 516min, respectively; P=0.4). VPGS had no impact on postoperative course: local or general complications, time to decannulation and nasogastric tube removal, or length of stay.
Conclusion:
VPGS significantly reduced fibula free-flap ischemia time. Long-term functional and esthetic benefit remains to be evaluated.
The purpose of the present study was to develop a computer-aided design (CAD) and computer-aided manufacturing (CAM) technique that enabled fabrication of surgical cutting guides and titanium fixation plates that would allow the upper maxilla to be repositioned correctly without a surgical splint in orthognathic patients.
Ten patients were recruited. A complete CAD-CAM workflow for orthognathic surgery has 3 steps: 1) virtual planning of the surgical treatment, 2) CAD-CAM and 3-dimensional printing of customized surgical devices (surgical cutting guide and titanium fixation plates), and 3) computer-aided surgery. Upper maxilla repositioning was performed in a waferless manner using a CAD-CAM device: the surgical cutting guide was used during surgery to pilot the osteotomy line that had been planned preoperatively at the computer and the custom-made fixation titanium plates allowed desired repositioning of the maxilla.
To evaluate the reproducibility of this CAD-CAM orthognathic surgical method, the virtually planned and actually achieved positions of the upper maxilla were compared. Overlap errors using a threshold value smaller than 2 mm were evaluated, and the frequency of such errors was used as a measurement of accuracy. By this definition, the accuracy was 100% in 7 patients (range in all patients, 62 to 100%; median, 92.7%).
These results tend to confirm that the use of CAD-CAM cutting guides and customized titanium plates for upper maxilla repositioning represents a promising method for the accurate reproduction of preoperative virtual planning without the use of surgical splints.
Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.
Objectives
This prospective study analyzed the accuracy of implant placement with mucosa-supported stereolithographic guides, executed by inexperienced surgeons supervised by an experienced colleague.Material and methodsFor the accuracy analysis, 75 OsseoSpeed implants™, placed in 17 fully edentulous jaws (16 patients) using a mucosa-supported stereolithographic guide (IMPLANT SAFE Guide, DENTSPLY Implants) and the Facilitate™ protocol, were included. DICOM images of the pre-surgical planning and the post-surgical CBCT were matched using the Mimics® software (Materialise Dental). These data were compared with the data (12 jaws, 52 implants) of an experienced surgeon (Vercruyssen et al. Journal of Clinical Periodontology 2014; doi:10.1111/jcpe.12231).ResultsThe global deviation at the coronal and apical point was 0.9 mm (SD 0.5) and 1.1 mm (SD 0.5), respectively. Depth deviations were 0.5 mm (SD 0.5) and 1.1 mm (SD 0.5), respectively, and the angular deviation was 2.8° (SD 1.5°). These deviations were statistically not inferior to the deviations of the experienced surgeon and also within the range of deviations reported by several systematic reviews.Conclusion
Within the limitations of this study and for the above-mentioned surgical protocol, inexperience of the surgeon had no influence on the accuracy of implant placement in fully edentulous jaws, when all steps needed for the procedure are supervised by experienced dentists.
Statement of problem:
Recently a new therapeutic concept of patient-specific implant dentistry has been advanced based on computer-aided design/computer-aided manufacturing technology. However, a comprehensive study of the design and 3-dimensional (3D) printing of the customized implants, their mechanical properties, and their biomechanical behavior is lacking.
Purpose:
The purpose of this study was to evaluate the mechanical and biomechanical performance of a novel custom-made dental implant fabricated by the selective laser melting technique with simulation and in vitro experimental studies.
Material and methods:
Two types of customized implants were designed by using reverse engineering: a root-analog implant and a root-analog threaded implant. The titanium implants were printed layer by layer with the selective laser melting technique. The relative density, surface roughness, tensile properties, bend strength, and dimensional accuracy of the specimens were evaluated. Nonlinear and linear finite element analysis and experimental studies were used to investigate the stress distribution, micromotion, and primary stability of the implants.
Results:
Selective laser melting 3D printing technology was able to reproduce the customized implant designs and produce high density and strength and adequate dimensional accuracy. Better stress distribution and lower maximum micromotions were observed for the root-analog threaded implant model than for the root-analog implant model. In the experimental tests, the implant stability quotient and pull-out strength of the 2 types of implants indicated that better primary stability can be obtained with a root-analog threaded implant design.
Conclusions:
Selective laser melting proved to be an efficient means of printing fully dense customized implants with high strength and sufficient dimensional accuracy. Adding the threaded characteristic to the customized root-analog threaded implant design maintained the approximate geometry of the natural root and exhibited better stress distribution and primary stability.
To present an efficient workflow for the production of implant drilling guides using virtual planning tools. For this purpose, laser surface scanning, cone beam computed tomography, computer-aided design and manufacturing, and 3-dimensional (3D) printing were combined.
Intraoral optical impressions (iTero, Align Technologies, Santa Clara, CA) and digital 3D radiographs (cone beam computed tomography) were performed at the first consultation of 1 exemplary patient. With image processing techniques, the intraoral surface data, acquired using an intraoral scanner, and radiologic 3D data were fused. The virtual implant planning process (using virtual library teeth) and the in-office production of the implant drilling guide was performed after only 1 clinical consultation of the patient. Implant surgery with a computer-aided design and manufacturing produced implant drilling guide was performed during the second consultation. The production of a scan prosthesis and multiple preoperative consultations of the patient were unnecessary.
The presented procedure offers another step in facilitating the production of drilling guides in dental implantology. Four main advantages are realized with this procedure. First, no additional scan prosthesis is needed. Second, data acquisition can be performed during the first consultation. Third, the virtual planning is directly transferred to the drilling guide without a loss of accuracy. Finally, the treatment cost and time required are reduced with this facilitated production process.
Total replacement of the temporomandibular joint (TMJ) is increasingly accepted as the gold standard for reconstruction of irreparably damaged or ankylosed joints. The TMJ Concepts system (TMJ Concepts, Ventura, USA) has the longest follow-up of the 2 systems used in the UK. A total of 74 patients had placement of TMJ Concepts prostheses. The primary diagnoses were degenerative disease, multiple previous operations, injury, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and ankylosis. Of these, 12 were revisions of previous replacements (3 after multiple operations). Over the year there was a significant mean (SD) reduction in pain score (10cm visual analogue scale) from 72 (2.5) to 8 (1.7) (p<0.0001), and mean (SD) improvements in mouth opening from 22.4mm (9.4) to 33.7mm (6.2) (p<0.0001), and dietary consistency (10cm analogue liquid 0 to solid 100) from 38 (23) to 93 (16) (p<0.0001). No patient had worse symptoms postoperatively. Joints in 2 patients failed because of biofilm infections. Two patients required blood transfusion and one required ligation of the external carotid artery. Five had perioperative dislocation, which responded to elastic intermaxillary fixation for one week. A total of 31 patients had partial, and 2 had total weakness of the facial nerve. All resolved fully except weakness of the temporal branch in one patient, which required brow lift. Total TMJ replacement gives good early improvements in function and pain with few complications. Of the 74 patients, 71 were very pleased to have had the procedure. One was dissatisfied despite complete pain relief and improvement in mouth opening from 3 to 30mm, and 2 were ambivalent (one had infection, revision, and permanent weakness of the temporal branch of the facial nerve).
To assess the safety and efficacy of a stock alloplastic total temporomandibular joint (TMJ) implant system, the Biomet Microfixation TMJ Replacement System.
During a 10-year multicenter clinical trial from 1995 to 2005, 442 Biomet Microfixation TMJ Replacement Systems were implanted in 288 patients (154 bilaterally and 134 unilaterally). Patients were followed at landmark times, including the date of surgery and at 1 month, 3 months, 1 year, 1 year 6 months, and 3 years. The 3 major metrics that were evaluated were preoperative and postoperative pain, interference with eating, and maximal incisal opening. Paired t tests and comparison analyses were used to assess outcomes.
There was statistically significant improvement in pain level (P = .0001), jaw function (P = .0001), and incisal opening (P = .0001). Although there were complications necessitating the removal of 14 of 442 implants (3.2%), there were no device-related mechanical failures.
The clinical study presented supports the conclusion that a stock TMJ alloplastic replacement, based on sound orthopedic and biomedical principles, is a safe and efficacious option when alloplastic reconstruction of the TMJ is indicated.
The aims of this study were to determine the accuracy of a 3D computer model and stereolithographic (STL) replica when compared to the real tooth and to develop a cone beam computed tomography (CBCT)-based planning technique including surgical guide fabrication. A STL surgical guide and a tooth replica were fabricated using SimPlant Pro 12.1. To validate this process, tooth segmentation and replica design were prepared for comparison to an optical scan of the corresponding tooth. For surgical intervention, a dry dentate mandible was scanned using a Scanora CBCT and the donor tooth was segmented. The donor tooth was repositioned, and two guides were designed. These tooth replica and guides were used in socket preparation of the dry mandible. The 3D computer model of the segmented teeth and related STL models showed satisfactory results with an acceptable accuracy. The surfaces were within 0·25mm distance, but in some areas up to 2·5mm deviation were seen. The results showed that 79% of the points was between 0·25 and -0·25mm, 3% was overestimated (>0·25mm) and 18% was underestimated (<-0·25mm). The computer-based repositioning of the donor tooth and construction of tooth replica and guide allowed socket preparation before donor tooth extraction and optimization of the STL procedure for in vivo planning of CBCT-based autotransplantation.
Presurgical planning is essential to achieve esthetic and functional implants. The goal of this clinical study was to determine the angular and linear deviations at the implant neck and apex between planned and placed implants using stereolithographic (SLA) surgical guides.
A total of 110 implants were placed using SLA surgical guides generated from computed tomography (CT). All patients used the radiographic templates during CT scanning. After obtaining 3-dimensional CT scans, each implant insertion was simulated on the CT images. SLA surgical guides using a rapid prototyping method including a laser beam were used during implant insertion. A new CT scan was made for each patient after implant insertion. Special software was used to match images of the planned and placed implants, and their positions and axes were compared.
The mean angular deviation of all placed implants was 4.1 degrees+/-2.3 degrees, whereas mean linear deviation was 1.11+/-0.7 mm at the implant neck and 1.41+/-0.9 mm at the implant apex compared with the planned implants. The angular deviations of the placed implants compared with the planned implants were 2.91 degrees+/-1.3 degrees, 4.63 degrees+/-2.6 degrees, and 4.51 degrees+/-2.1 degrees for the tooth-supported, bone-supported, and mucosa-supported SLA surgical guides, respectively.
The results of this study suggested that stereolithographic surgical guides using CT data may be reliable in implant placement, and tooth-supported SLA surgical guides were more accurate than bone- or mucosa-supported SLA surgical guides.
Dental implant placement requires precise planning with regard to anatomic limitations and restorative goals. The aim of this study was to evaluate the match between the positions and axes of the planned and placed implants using stereolithographic (SLA) surgical guides.
Ninety-four implants were placed using SLA surgical guides generated from computed tomography (CT) between 2005 and 2006. Radiographic templates were used for all subjects during CT imaging. After obtaining three-dimensional CT images, each implant was virtually placed on the CT images. SLA surgical guides, fabricated using an SLA machine with a laser beam to polymerize the liquid photo-polymerized resin, were used during implant placement. A new CT scan was taken for each subject following implant placement. Special software was used to fuse the images of the planned and placed implants, and the locations and axes were compared.
Compared to the planned implants, the placed implants showed angular deviation of 4.9 degrees+/-2.36 degrees, whereas the mean linear deviation was 1.22+/-0.85 mm at the implant neck and 1.51+/-1 mm at the implant apex. Compared to the implant planning, the angular deviation and linear deviation at the neck and apex of the placed maxillary implants were 5.31 degrees+/-0.36 degrees, 1.04+/-0.56 mm, and 1.57+/-0.97 mm, respectively, whereas corresponding figures for placed mandibular implants were 4.44 degrees+/-0.31 degrees, 1.42+/-1.05 mm, and 1.44+/-1.03 mm, respectively.
SLA surgical guides using CT data may be reliable in implant placement and make flapless implant placement possible.
Autotransplantation is a viable option for treating missing teeth when a donor tooth is available. The aim of this study was to evaluate the prognosis in addition to the causes of failure in 182 autotransplanted teeth.
A total of 182 cases of autotransplantation were analyzed. All the transplants were performed according to a computer-aided rapid prototyping technique with an average extraoral time of 7.58 minutes. These cases were followed for 2 to 60 months after surgery. The prognosis was divided into 4 groups, complete healing, incomplete healing, uncertain healing, and failure. The initial stability, root resorption, and ankylosis were also analyzed.
Most transplanted teeth showed complete healing between postoperative 2 months and 8 months. The transplanted teeth with a good initial stability showed better initial healing than those with a poor initial stability. The average extraoral time was 7.58 min (range: immediately after extraction up to 25 min). There was no relationship (P > .05) between the extraoral time and either root resorption (4 cases, 2.4%) or ankylosis (18 cases, 10.7%) within this experimental time period. Nine cases (4.5%) failed.
This study showed a 4.5% failure rate during the short to intermediate observation period. Autotransplantation is a very useful method for replacing missing teeth, provided that the extraoral time and other factors are well controlled.
Flapless implant surgery has been suggested as one possible treatment option for enhancement of implant esthetics.
Twenty-four patients with a missing tooth in the premaxillary region were randomly assigned to one of two groups (12 each): immediate loading (IL) or delayed loading (DL) (loading after 4 months). An endosseous implant was placed in each patient via a flapless surgery. Clinical measurements including the papillary index (PPI) (0, no papilla; 1, less than half; 2, more than half but not complete fill; 3, complete fill; and 4, overfill), marginal levels of the soft tissue (ML), probing depths (PDs), modified bleeding index (mBI), modified plaque index (mPI), and the width of the keratinized mucosa (WKM) were performed at baseline (at the time of loading) and at 2, 4, and 6 months.
The soft tissue profile remained stable up to 6 months, without significant differences between the two groups (mean PPI and ML at 6 months, 2.16 and 0.30 mm, respectively). Mean PPI in the IL group significantly increased from 1.50 at baseline to 2.09 at 2 months, and the significance remained up to 6 months (2.30 at 6 months) (P <0.05), whereas in the DL group, no significant changes were found from baseline to 6 months in mean PPI (2.06 at both time points). Mean PPI increased over time when two treatment groups were combined; however, no statistical significance was found. In ML, the difference at baseline between the two groups (-0.28 mm for DL versus 0.17 mm for IL; P <0.05) was no longer significant at 2 months (0 versus 0.08 mm for DL and IL, respectively) and thereafter (P >0.05). No significant differences were detected between groups at each time and over time in the other clinical parameters, PD, mBI, mPI, and WKM (P >0.05).
The results of this study indicate that creeping attachment (i.e., soft tissue recovery) might occur within 2 months after IL. The study suggests that flapless implant surgery provides esthetic soft tissue results in single-tooth implants either immediately or delayed loaded. Other long-term randomized controlled clinical trials with a large sample size and comparison group (i.e., implant surgery with flap) are recommended to verify the conclusions drawn in this preliminary study.
For more than 20 years, researchers have been trying to automate conventional manual processes in dental technology with the hope of producing higher- and more uniform-quality materials, standardizing manufacturing processes and reducing production costs.
The authors review existing computer-aided design (CAD)/computer-aided manufacturing (CAM) systems, describing the components of CAD/CAM technologies and addressing the limitations of current systems, and suggest possibilities for future systems.
Existing dental CAD/CAM systems vary dramatically in their capabilities; each has distinct advantages and limitations. None can yet acquire data directly in the mouth and produce the full spectrum of restoration types (with the breadth of material choices) that can be created by traditional techniques. Emerging technologies may expand dramatically the capabilities of future systems, but they also may require a different type of training to use them to their full effectiveness.
In the future, automatically fabricated, fully esthetic restorations might be produced more quickly and have longer lifetimes than restorations currently produced with CAD/CAM systems.
Because osseointegration is now considered highly predictable, the current trend is to develop techniques that can provide function, esthetics, and comfort with a minimally invasive surgical approach. To achieve those goals, flapless implant surgery using a tissue punch technique has been suggested. This paper presents two clinical cases of single-tooth implants placed in the esthetic region (anterior maxilla), which illustrate systematic approaches to flapless implant surgery for immediate and delayed loading protocol. For both cases, a tissue punch technique using a surgical guide fabricated with the aid of a radiographic stent was performed to provide access for implant site preparation and placement. The implants were loaded either immediately or 4 months after implant placement. With the planned flapless surgical technique, reduced operative time, accelerated postsurgical healing, and increased patient comfort and satisfaction were achieved. This paper also describes precautions of the flapless implant surgery in case selection, surgical techniques, and prosthodontic protocol. In conclusion, appropriate case selection and well-tailored surgical guides with sound surgical and prosthodontic protocols are considered to be the key elements in the success of flapless implant surgery.
A new technique for producing splints for orthognathic surgery using a 3D printer is presented.
After 3-dimensional (3D) data acquisition by computerized tomography (CT) or cone-beam computerized tomography (CBCT) from patients with orthognathic deformations, it is possible to perform virtual repositioning of the jaws. To reduce artifacts, plaster models were scanned either simultaneously with the patient during the 3D data acquisition or separately using a surface scanner. Importing and combining these data into the preoperative planning situation allows the transformation of the planned repositioning and the ideal occlusion. Setting a virtual splint between the tooth rows makes it possible to encode the repositioning. After performing a boolean operation, tooth impressions are subtracted from the virtual splint. The "definitive" splint is then printed out by a 3D printer.
The presented technique combines the advantages of conventional plaster models, precise virtual 3D planning, and the possibility of transforming the acquired information into a dental splint.
In this report, we describe computer-based design and production of occlusal splints. A research effort was undertaken to develop a process to eliminate the inherent variabilities associated with current splint-fabrication methods. The digital process provides quantitative control over articulation and splint design, and produces splints with continuously smooth occlusal surfaces. Stone casts are laser scanned, and custom software is used to articulate and design flat-plane and full-coverage splints with guidance ramps. Splints are produced by milling excess acrylic placed over stone casts. Clinically, digital splints reduce the average time needed for placement because intraoral equilibration is minimized.
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