Abstract
The capacity of additive manufacturing and three-dimensional (3D) printing to quickly construct intricate structures and accurate geometries sets them apart from traditional production techniques. The fourth industrial revolution and the digitalization of production were fueled by the emergence of 3D printing, which was made possible by the increasing demand for goods with various designs, functions, and materials. The global influence of 3D printing on healthcare has resulted in the replacement of generic implanted medical devices with patient-customized implants. In the field of oral and maxillofacial surgery, where surgeons use precision medicine daily, this revolution has had a huge influence. Treatments enhanced by 3D technology include orthognathic surgery, complete joint replacement therapy, and trauma. Surgical teams now engage in the 3D design and production of devices at point-of-care treatment facilities with internal infrastructure thanks to the growing and broad adoption of 3D technology in clinical settings. The way doctors approach treatment planning and clinical results are affected greatly by 3D technology. While outlining significant clinical applications, the article presents our viewpoint on the use of 3D-based technology in the field of oral and maxillofacial surgery and the road ahead with the advent of Four-dimensional (4D) printing.
Keywords: Three dimensional planning, Stereolithography, Future perspective, Virtual surgery
Introduction
Three-dimensional (3D) printing or additive manufacturing is the term used to imply construction of a three-dimensional object or a digital 3D model from a Computer Aided Design (CAD) processing Unit. The introduction of 3D printing in medicine has opened a plethora of possibilities which have resulted in upgraded training modules, improved results across surgical applications by decreasing costs, reducing surgical time and enhanced outcomes of the treatments.1,2
Historical perspective – the journey so far
As early as 1971, Johannes F Gottwald patented the Liquid Metal Recorder, U.S. patent ID 3596285A, which was a continuous inkjet metal material device which formed a removable metal fabrication on a reusable surface for immediate use or recycled for printing again by remelting. This was the first ever patent describing 3D printing with rapid prototyping.2
Earliest reference to 3D printing technology, which has been the guiding force behind modern-day 3D printing, was known as Rapid Prototyping (RP) and the first rapid prototyping patent application was submitted by a Japanese, Dr. Hideo Kodama in the year 1980. This layer-by-layer approach or additive method of manufacturing was the first of its kind but unfortunately not pursued as Dr Kodama failed to file for the patent within the prescribed 1-year deadline and hence denied the patenting right to his pioneering work. The idea, however, opened the floodgates for innovative cutting-edge technological developments, subsequently leading to Additive Manufacturing which we today know as rapid prototyping, or simply 3D printing.3,4
Dr. Charles Hull in 1983 invented Stereolithography (SLA) which he patented in 1986. He later used lasers to selectively cure photopolymer within a pool of liquid resin.5
Dr. Carl Deckard in 1988 utilized Lasers to selectively melt powdered plastic into a solid structure and thus invented Selective Laser Sintering or SLS printing (Fig. 1).6
Fig. 1.
Selective Laser Sintering (SLS) printing mechanism.
Dr. Scott Crump in 1989 introduced Fused Deposition Modelling (FDM) which does additive manufacturing by using a plastic filament forced through various size nozzles, like a hot glue gun (Fig. 2).6
Fig. 2.
Fused Deposition Modeling (FDM) printing mechanism.
From the 1990s till date, further upgradation in technology has flooded the market with newer 3D printing methods namely Direct Metal Laser Sintering (DMLS) which directly prints the metallic models (Fig. 3).7
Fig. 3.
Direct Metal Laser Sintering (DMLS).
In 2016, Multi Jet Fusion (MJF) technology was introduced with a resolution which is considerably better than the typical 100 to 300 microns or more found in FDM prints with layer height between 70 and 100 microns (Fig. 4).
Fig. 4.
Multi Jet Fusion (MJF) printing mechanism.
Current status
The 3D printing technology has not left any frontier unconquered and from a urinary bladder in 1999 to the first Titanium mandible in 2009, it has come a long way and finds applications in a plethora of clinical situations in almost every sphere of the health care sciences.
Maxillofacial region is a challenging anatomical part of the human skeleton which has an intricate intertwined hard tissue overlaid by even complex soft tissue envelope. Maxillofacial deformities arising due to developmental anomalies, trauma or ablative cancer surgeries pose a challenge to a Surgeon due to alteration in form, function and esthetics.3
Trauma, orthognathic surgery and total Temporomandibular (TM) Joint replacement surgery represent several fields wherein 3D printing has considerably improved treatment outcomes.
As 3D printing has become more accessible and affordable to the end user with the improved software support as well as the ingenuity of the clinician, more and more avenues of its applications are being explored with each passing day. Be it the virtual planning, post-graduate training by way of mock surgery on the 3D models, fabrication of the cutting guides or even splints for orthognathic surgeries or customized patient-specific implant, the list is exhaustive (Fig. 5, Fig. 6, Fig. 7, Fig. 8).
Fig. 5.
Virtual 3D planning for customized Titanium Cranioplasty.
Fig. 6.
Vector planning and placement of distraction device on an Fused Deposition Modelling (FDM).
Fig. 7.
Virtual 3D model for fabrication of patient-specific hemimandible implant.
Fig. 8.
Virtual Orthognathic surgical planning in a Bijaw surgery case.
In a nutshell, there are endless possibilities to its utility in the field of Oral health Sciences in general and maxillofacial surgery in particular.
Thanks to high-resolution imaging, the practitioner or the clinician requires no CAD/CAM knowledge and is just required to import DICOM® (Digital Imaging and Communications in Medicine) image data and the 3D-printing software processes it in no time and transfers this information into an additive printer or any of the available 3D printers which in turn prints a 3D model. In addition, clinicians can even outsource the entire 3D workflow and the subsequent surgical implant fabrication to numerous companies offering these services. There is a plethora of 3D-printable materials which are both biocompatible and cost-effective and are commercially available for application in reconstruction purposes. The fabrication of these high-precision models and prosthesis is facilitated by Artificial Intelligence (AI) based software e.g., IPS Case Planner (KLS Martin, Tuttlingen, Germany) which can spatially orient the defects involving even completely missing bone and other facial structures besides simplification of cephalometric analysis, splint fabrication production and simulation of the entire surgical process in orthognathic surgery. The AI software aids in a better visualization of complex anomalies like occlusal canting, yaw rotations and any corpus deficiency in the mandibular subunits viz., the body or ramus.8
Materials of improved strength characteristics and long-term durability are available for surgical applications, such as TM joint prostheses, patient-specific implants. Reconstruction of the glenoid fossa and mandibular component requires different metallic and non-metallic materials that precisely replicate the anatomical part besides providing functionality with enduring strength. The advent of 3D-printed guides has ensured that patients are no longer subjected to multiple surgeries for procedures such as condylectomy and prosthetic TM Joint replacement.
The technique of 3D printing has an emerging role and endless possibilities in the field of maxillofacial surgery. 3D printed stereolithographic models are a value addition in better preoperative evaluation of facial defect/deformity and treatment planning. While the present-day applications include fabrication of anatomical models which can be used for training purposes, surgical guides/splints for osteotomy cuts in resective and Orthognathic surgeries and customized patient-specific implants are some other areas where in 3D additive technology can be used with encouraging results.
The use of 3D-printed surgical guides for placement of dental implant is a well-established technological aid and has consistently shown to significantly decrease both the surgical time and the inadvertent errors that may occur when the implant osteotomy is prepared without surgical guides. The fabrication of dental implants using 3D printing is also being increasingly adopted. Some studies on bone healing rates for a variety of structures and implant materials have indicated high rates of implant success. The Armed Forces have been a pioneer in this field as well and the first customized 3D printed Titanium Hemimandible was placed as early as June 2021 which was ahead of many centers of excellence in the country (Fig. 9).
Fig. 9.
First 3D printed customized Titanium Hemimandible of the AFMS.
Despite the advent of cutting-edge technology, surgeon's ingenuity and meticulous planning, soft tissue coverage in Mucormycosis and ablative surgery cases treated with PSI poses a significant challenge. The solutions for the soft tissue coverage that are available range from local tissue flaps like palatal and nasolabial flaps for smaller defects to axial pattern/microvascular free flaps for larger defects, wherein a multidisciplinary team intervention gives a better patient outcome. Also, the overall dimensional profiles of the PSI can be customized based on age, sex and the type of residual tissue available for a satisfactory closure and a long-term stable result.
The road ahead
3D bioprinting is the cutting-edge innovation of additive manufacturing employed in printing not just inanimate objects but also cells, growth factors and/or biomaterials too, which mimic the natural tissue characteristics,9 four-dimensional (4D) printing is an additive manufacturing process in which the printed object has an inherent memory and the ability to alter its shape with time, temperature, or some other type of induced stimulation. 4D printing allows creation of dynamic structures with adjustable shapes, properties and functionality. These smart and stimulus-responsive materials created using 4D printing can be activated with an aim to create calibrated responses such as self-assembly, self-repair, multi-functionality and reconfiguration. This facilitates customized printing of materials which have inherent shape-changing and shape-memory properties.9,10
Conclusion
3D printing and virtual treatment planning hold a lot of promise for the future and the scope of its applications in maxillofacial surgery is immense. One should embrace this technology with open arms as it has a positive influence on every aspect of treatment planning, training of the aspiring Maxillofacial surgeons, as well as treatment outcomes in every possible surgical procedure.
Disclosure of competing interest
The authors have none to declare.
References
- 1.Gao Wei, Zhang Yunbo, Ramanujan Devarajan, et al. The status, challenges, and future of additive manufacturing in engineering. Comput Aided Des. 2015;69:65–89. doi: 10.1016/j.cad.2015.04.001. [DOI] [Google Scholar]
- 2.Ngo Tuan D., Kashani Alireza, Imbalzano Gabriele, Nguyen Kate T.Q., Hui David. Additive manufacturing (3D printing): a review of materials, methods, applications and challenges. Compos B Eng. 2018;143:172–196. [Google Scholar]
- 3.Lam Hugo K.S., Ding Li, Cheng T.C.E., Zhou Honggeng. The impact of 3D printing implementation on stock returns: a contingent dynamic capabilities perspective. Int J Oper Prod Manag. 2019;39(6/7/8):935–961. [Google Scholar]
- 4.Prakash P., Bahri R., Bhandari S.K. Beauty - Cosmetic Science, Cultural Issues and Creative Developments. Intech Open; 2021. Maxillofacial defects: impact on psychology and esthetics. [Internet] [Google Scholar]
- 5.Freedman David H. Layer by layer. Technol Rev. 2012;115(1):50–53. [Google Scholar]
- 6.Barnatt Christopher. 3D printing: the next industrial revolution. Atlantic Publishers and Distributors Nottingham, England. 2013:15–18. [Google Scholar]
- 7.Prinz F.B., Merz R., Weiss Lee. In: Building Parts You Could Not Build before. Proceedings of the 8th International Conference on Production Engineering. Ikawa N., editor. Chapman & Hall; London, UK: 1997. pp. 40–44. [Google Scholar]
- 8.Wu T.Y., Lin H.H., Lo L.J., Ho C.T. Postoperative outcomes of two- and three-dimensional planning in orthognathic surgery: a comparative study. J Plast Reconstr Aesthetic Surg. 2017;70:1101–1111. doi: 10.1016/j.bjps.2017.04.012. [DOI] [PubMed] [Google Scholar]
- 9.Wu Peng, Wang Jun, Wang Xiangyu. A critical review of the use of 3-D printing in the construction industry. Autom ConStruct. 2016;68:21–31. [Google Scholar]
- 10.Momeni Farhang, Liu Xun, Ni Jun. A review of 4D printing. Mater Des. 2017;122:42–79. [Google Scholar]