Dental News - New comprehensive review of 3D printing in oral and maxillofacial surgery

Anisha Hall Hoppe, Dental Tribune International

Mon. 8. May 2023

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BOSTON, US/KARAJ, Iran: The introduction of 3D printing in medicine has improved outcomes across surgical applications by decreasing costs, reducing surgical time and improving reliability of treatments. Researchers from the Harvard School of Dental Medicine and the Alborz University of Medical Sciences in Iran have created a handy summary of the current advances of 3D printing in the field of oral and maxillofacial surgery (OMFS) that offers clinicians a brief explanation of 3D printing and a broader look at how 3D printing can be used for specific purposes in OMFS.

Clinicians need not have a strong understanding of engineering or materials science to be able to utilise 3D printing in their treatment plans. Indeed, merely understanding the differences between the various 3D-printing methodologies is an adequate place to start. Thanks to high-resolution imaging, the practitioner need only import image data and many 3D-printing software packages will process and render this information into a printable model, for which the clinician requires no CAD/CAM knowledge. In addition, clinicians can even outsource overall virtual surgical planning and surgical implant fabrication to the numerous companies now offering these services.

In their review, the researchers give a simple description of CAD/CAM’s role in realising implants and surgical solutions bringing implants and surgical solutions to life. Computer-rendered 3D models and printed guides advance surgery for maxillofacial trauma and reconstruction, reducing surgical time by ensuring bones are repositioned correctly, for example. Printed cutting guides improve surgical results, and even before surgery, CAD programs can calculate symmetry in areas of bone defects for restoration with CAM devices.

The power of visualisation

3D-printed models significantly aid in patient education and communication, helping clinicians demonstrate the desired results of the planned procedure, particularly when the trauma or area of reconstruction is difficult to understand. CAD enables clinicians to even work with parents to prepare for needed corrections, such as for a known cleft palate, while their child is still in utero.

This ease of visualisation is particularly useful in complicated procedures such as those of orthognathic surgery. During the procedure, printed osteotomy guides ensure that bone segments are placed correctly, dental roots and nerves are avoided, and complicated asymmetric movements can be achieved when desired. Additionally, 3D printing of titanium plates that are completely customised to patient anatomy ensure ongoing stability and strength of the bone.

A safer option

3D printing has also meant that microvascular reconstruction is no longer necessary in cases of reconstruction, as bone harvesting and transplantation has become a thing of the past. In maxillofacial prosthodontics, the risk of infection and obstruction of anatomical structures, among other issues, are already challenging enough without having to deal with problems such as donor site morbidity and added patient pain. There are a number of 3D-printable materials available for various reconstruction purposes that are both biocompatible and cost-effective, and designated software can easily remodel defects or completely missing bone and other facial structures into a symmetrical, aesthetic and functional result.

Materials of incredible strength and durability are available for surgical purposes, such as for temporomandibular joint prostheses. Reconstruction of the fossa and mandibular component requires different materials that work together and provide enduring strength. The advent of 3D-printed guides has meant that are patients no longer subjected to multiple surgeries for a procedure such as a condylectomy and prosthetic replacement. The authors do note that more research needs to be done into the new procedures that utilise some device or scaffolding solutions, as there is still a lack of information on how patient-tailored prostheses affect muscle and joint function in the long term.

The use of 3D-printed surgical guides for dental implant placement is well documented and has been shown to dramatically decrease both the surgery time and the errors that may arise from freehand drilling. The fabrication of dental implants too using 3D printing is being increasingly investigated. Some studies on bone healing rates for a variety of structures and implant materials have indicated high rates of implant success, but long-term clinical evidence is lacking.

Bone tissue engineering has shown significant progress, researchers all over the world having developed scaffolding solutions that rely on various combinations of designs, cell sources and biomaterials, among others, all tailored to patient-specific anatomy. There is much more still to be done, and the authors note a bright future for research in regeneration of neural and vascular networks, ensuring mechanical properties and more. It is also a field without much medical regulation and one that would benefit from more clinical studies, particularly considering the advances expected in bioactive synthetic materials in the coming years. The authors cite the success in one study of a 3D-printed scaffold for a cleft palate restoration that utilised bone marrow stromal cells and achieved new bone growth in 45% of the defect volume after just six months.

The need for updated curriculum

The review also highlights the overarching benefits of utilising 3D-printed models in clinician education, particularly because realistic, easy-to-access models can be printed anywhere and can be customised to virtually any training situation or patient model. 3D printing using both soft and hard materials can produce a lifelike cleft lip and palate model in a single print, for example. Researchers are constantly re-evaluating model creation based on surveys of tactile and haptic feedback and how realistic a model is compared with the real thing.

In addition to a list of materials and their associated applications across OMFS, the authors include some associated risks with 3D printing, including need for further classification of devices. They also note that clinicians should take the time to educate themselves on not only the associated costs of 3D printing but also the technology that they specifically will require. Not every material is compatible with every printer, and skilled technicians are essential for the various steps of the 3D-printing process. 3D printing itself involves the risks of exposure to chemicals, possibly lasers or other sources of injury and should really be undertaken with proper assistance. Though clinicians should not feel hesitant in adopting 3D printing, it is not as simple as printing and implanting. There are a myriad of sources on the topic and a number of companies specialising in helping clinicians use 3D-printed surgical solutions immediately, safely and with efficacy.

The study, titled “The impact of 3D printing on oral and maxillofacial surgery”, was published online on 14 April 2023 in the Journal of 3D Printing in Medicine, ahead of inclusion in an issue.