Novel Treatment Planning of Hemimandibular Hyperplasia by the Use of Three-Dimensional Computer-Aided-Design and Computer-Aided-Manufacturing Technologies

Point-of-Care Virtual Surgical Planning and 3D Printing in Oral and Cranio-Maxillofacial Surgery: A Narrative Review

This paper provides an overview on the use of virtual surgical planning (VSP) and point-of-care 3D printing (POC 3DP) in oral and cranio-maxillofacial (CMF) surgery based on a literature review. The authors searched PubMed, Web of Science, and Embase to find papers published between January 2015 and February 2022 in English, which describe human applications of POC 3DP in CMF surgery, resulting in 63 articles being included. The main review findings were as follows: most used clinical applications were anatomical models and cutting guides; production took place in-house or as "in-house-outsourced" workflows; the surgeon alone was involved in POC 3DP in 36 papers; the use of free versus paid planning software was balanced (50.72% vs. 49.27%); average planning time was 4.44 h; overall operating time decreased and outcomes were favorable, though evidence-based studies were limited; and finally, the heterogenous cost reports made a comprehensive financial analysis difficult. Overall, the development of in-house 3D printed devices supports CMF surgery, and encouraging results indicate that the technology has matured considerably.

Methods of Definitive Correction of Mandibular Deformity in Hemimandibular Hyperplasia Based on Radiological, Anatomical, and Topographical Measurements-Proposition of Author's Own Protocol

In order to fully evaluate and establish the degree of bone overgrowth, various radiological studies are essential in the careful planning of the amount of surgical excision. In the presented paper, the authors use self-designed anatomo-topographical reference points for planning the surgeries. Routine panoramic radiographs and low-dose computed tomography based on anatomical landmarks help in measuring the proportions of mandibular bone overgrowth with the following preoperative anatomical landmarks: (Go-Go), (Go(Right)-Gn), (Go(Left)-Gn), and (Me−Gn). Measurements taken at selected points and landmarks (gonion-gnathion/gnathion-menton) are easy to conduct. In the authors’ proposal, the main key factor is total chin correction, which is necessary in cases of severe overgrowth; when F0 > C and Go-Gn>, there is >7 mm of vertical bone overgrowth, and the mandibular canal is positioned <5 mm from the inferior mandibular border—MIB. Larger overgrowths (>7 mm) have a greater outcome on the final symmetry than smaller overgrowths. As no guidelines are known, the authors present their own proposal.

The Role of Three-Dimensional Printing Technology as an Additional Tool in Unilateral Condylar Hyperplasia Surgical Planning

The purpose of this study is to evaluate whether additive manufactory technology through the use of 3D mandible and skull cast models can provide additional support to the virtual surgical planning for patients affected by unilateral condylar hyperplasia (UCH). This study describes 2 patients affected by active UCH. Cone beam computed tomography (CBCT) scans were converted in STL files and then sent to a 3D printer that provided 3D cast models of patient's mandible and skull. Surgical planning was conducted performing linear measurement both on 3D virtual images and on 3D cast models. Proportional condylectomy was then simulated with the virtual software and on the 3D cast models as well. After 18 months, new CBCT scans of the patients were acquired and new 3D cast models were printed. Measurements performed on the 3D cast models were close and reliable if compared to measurements obtained on 3D virtual images. None of the patients underwent further surgeries obtaining stable results in terms of symmetry. 3D printing technologies have a relevant support for a more accurate planning and surgical treatment in UCH.

Dental 3D-Printing: Transferring Art from the Laboratories to the Clinics

The rise of three-dimensional (3D) printing technology has changed the face of dentistry over the past decade. 3D printing is a versatile technique that allows the fabrication of fully automated, tailor-made treatment plans, thereby delivering personalized dental devices and aids to the patients. It is highly efficient, reproducible, and provides fast and accurate results in an affordable manner. With persistent efforts among dentists for refining their practice, dental clinics are now acclimatizing from conventional treatment methods to a fully digital workflow to treat their patients. Apart from its clinical success, 3D printing techniques are now employed in developing haptic simulators, precise models for dental education, including patient awareness. In this narrative review, we discuss the evolution and current trends in 3D printing applications among various areas of dentistry. We aim to focus on the process of the digital workflow used in the clinical diagnosis of different dental conditions and how they are transferred from laboratories to clinics. A brief outlook on the most recent manufacturing methods of 3D printed objects and their current and future implications are also discussed.

Sequential application of novel guiding plate system for accurate transoral mandibular reconstruction

OBJECTIVES

The aim of this article is to introduce and share our experience in the sequential use of a novel guiding plate system for accurate mandibular reconstruction via transoral approach and evaluate its clinical effects.

METHODS

Ten patients were operated with transoral mandibulectomy and simultaneous mandibular reconstruction using a novel guiding plate system. Postoperatively, aesthetic assessment and quantitative evaluation were analyzed by measuring the parameters like discrepancy in osteotomy lines, mandibular similarity and symmetry. The independent samples t-test was used and P < 0.05 was considered as significant.

RESULTS

All patients underwent planned transoral surgical procedure successfully. The postoperative aesthetic assessment was rated as excellent. The discrepancy between virtual and actual osteotomy lines, at anterior and posterior regions was 0.80 ± 0.08 and 0.98 ± 0.37 mm, respectively. The postoperative evaluation revealed that mandibular similarity was 0.85 ± 0.03, coronal mandibular angle (CMA) 0.66 ± 0.40, axial mandibular angle (AMA) 1.97 ± 1.25, and sagittal mandibular angle (SMA) 1.97 ± 1.05. There was statistically significant difference in the mean values of osteotomy line discrepancy, mandibular similarity and symmetry, among novel guiding plate and traditional plate groups.

CONCLUSIONS

The novel guiding plate system is a viable and easy-to-use technology for improving the surgical outcomes in patients requiring transoral mandibulectomy and simultaneous mandibular reconstruction by overcoming the problem of limited access due to the presence of lips and cheeks. This can highly improve the precision in osteotomy, fixation of the prebent titanium reconstruction plate, spatial relation transfer, and achieving better symmetry and similarity of mandibular contour.

Evaluation of Imaging Software Accuracy for 3-Dimensional Analysis of the Mandibular Condyle. A Comparative Study Using a Surface-to-Surface Matching Technique

The aim of this study was to assess the accuracy of 3D rendering of the mandibular condylar region obtained from different semi-automatic segmentation methodology. A total of 10 Cone beam computed tomography (CBCT) were selected to perform semi-automatic segmentation of the condyles by using three free-source software (Invesalius, version 3.0.0, Centro de Tecnologia da Informação Renato Archer, Campinas, SP, Brazil; ITK-Snap, version2.2.0; Slicer 3D, version 4.10.2) and one commercially available software Dolphin 3D (Dolphin Imaging, version 11.0, Chatsworth, CA, USA). The same models were also manually segmented (Mimics, version 17.01, Materialise, Leuven, Belgium) and set as ground truth. The accuracy of semi-automatic segmentation was evaluated by (1) comparing the volume of each semi-automatic 3D rendered condylar model with that obtained with manual segmentation, (2) deviation analysis of each 3D rendered mandibular models with those obtained from manual segmentation. No significant differences were found in the volumetric dimensions of the condylar models among the tested software (p > 0.05). However, the color-coded map showed underestimation of the condylar models obtained with ITK-Snap and Slicer 3D, and overestimation with Dolphin 3D and Invesalius. Excellent reliability was found for both intra-observer and inter-observer readings. Despite the excellent reliability, the present findings suggest that data of condylar morphology obtained with semi-automatic segmentation should be taken with caution when an accurate definition of condylar boundaries is required.

Utilization of a Simple Surgical Guide for Multidirectional Cranial Distraction Osteogenesis in Craniosynostosis

Background:

Multidirectional cranial distraction osteogenesis (MCDO) can achieve a desired shape for deformities of the cranium. In the past, visual estimation was used to reflect on the actual skull, but it was time-consuming and inaccurate. Here we demonstrate an effective osteotomy navigation method using surgical guides made from a dental impression silicone.

Methods:

Seven patients who underwent MCDO between August 2013 and September 2016 were included in the study. Five cases involved utilization of the surgical guide for osteotomy. Three-dimensional (3D) printed cranium models were made using 3D computed tomography (3DCT) imaging data and dental impression silicone sheets were molded using the printed cranium models. These surgical guides were sterilized and used for intraoperative osteotomy design. Vertical distance between nasion/porion and osteotomy lines were calculated using 3D printed cranial models and postoperative 3DCT images to assess reproducibility.

Results:

The average surgical time/design time was 535/37.0 minutes for the nonsurgical guide group and 486.8/11.8 minutes for the surgical guide group (SG).Treatment using the surgical guide was significantly shorter in terms of operative time and time required for design. For the vertical distance comparison, the average distance was 5.7mm (SD = 0.3) in the non-SG and 2.5mm (SD = 0.44) in the SG, and SG was more accurate.

Conclusions:

Shorter operative times and higher reproducibility rates could be achieved by using the proposed surgical guide, which is accurate, low-cost, and easily accessible.

Intraoperative imaging and navigation with mobile cone-beam CT in maxillofacial surgery

INTRODUCTION

Intraoperative mobile Cone-Beam Computed Tomography (CBCT) trends to develop for the management of complex facial fractures. It allows a real-time imaging and surgical navigation.

AIM

Through the presentation of two clinical cases, we aimed at presenting the procedure of intra-operative CBCT and new applications in maxillofacial surgery.

RESULTS

A young patient with extended orbito-frontal fibrous dysplasia, and a child with the recurrence of a temporomandibular joint ankylosis secondary to mastoïditis, were operated using a intra-operative imaging control. In both cases, the intraoperative CBCT increased precision and safety of the bone resection. No surgical complication was noted and a good healing was obtained.

CONCLUSION

Intraoperative CBCT raises the problems of radiation exposure and increased operating time. However, it represents a useful imaging tool and a navigation system in complex situations as osseous dysplasia and surgery of the temporo-mandibular joint.

Developing an In-house Interdisciplinary Three-Dimensional Service: Challenges, Benefits, and Innovative Health Care Solutions

Three-dimensional printing (3DP) technologies have been employed in regular medical specialties. They span wide scope of uses, from creating 3D medical models to design and manufacture of Patient-specific implants and guidance devices which help to optimize medical treatments, patient education, and medical training. This article aims to provide an in-depth analysis of factors and aspects to consider when planning to setup a 3D service within a hospital serving various medical specialties. It will also describe challenges that might affect 3D service development and sustainability and describe representative cases that highlight some of the innovative approaches that are possible with 3D technology. Several companies can offer such 3DP service. They are often web based, time consuming, and requiring special call conference arrangements. Conversely, the establishment of in-house specialized hospital-based 3D services reduces the risks to personal information, while facilitating the development of local expertise in this technology. The establishment of a 3D facility requires careful consideration of multiple factors to enable the successful integration with existing services. These can be categorized under: planning, developing and sustaining 3D service; 3D service resources and networking workflow; resources and location; and 3D services quality and regulation management.