A novel 3D template for mandible and maxilla reconstruction: Rapid prototyping using stereolithography

Abstract

Introduction:Replication of the exact three-dimensional (3D) structure of the maxilla and mandible is now a priority whilst attempting reconstruction of these bones to attain a complete functional and aesthetic rehabilitation. We hereby present the process of rapid prototyping using stereolithography to produce templates for modelling bone grafts and implants for maxilla/mandible reconstructions, its applications in tumour/trauma, and outcomes for primary and secondary reconstruction.Materials and Methods:Stereolithographic template-assisted reconstruction was used on 11 patients for the reconstruction of the mandible/maxilla primarily following tumour excision and secondarily for the realignment of post-traumatic malunited fractures or deformity corrections. Data obtained from the computed tomography (CT) scans with 1-mm resolution were converted into a computer-aided design (CAD) using the CT Digital Imaging and Communications in Medicine (DICOM) data. Once a CAD model was constructed, it was converted into a stereolithographic format and then processed by the rapid prototyping technology to produce the physical anatomical model using a resin. This resin model replicates the native mandible, which can be thus used off table as a guide for modelling the bone grafts.Discussion:This conversion of two-dimensional (2D) data from CT scan into 3D models is a very precise guide to shaping the bone grafts. Further, this CAD can reconstruct the defective half of the mandible using the mirror image principle, and the normal anatomical model can be created to aid secondary reconstructions.Conclusion:This novel approach allows a precise translation of the treatment plan directly to the surgical field. It is also an important teaching tool for implant moulding and fixation, and helps in patient counselling.

Automated Planning With Multivariate Shape Descriptors for Fibular Transfer in Mandibular Reconstruction

“…3) E r : objective function using symmetric distance defined by (7). This model is a possible automatic planning based on a previous mirror-image-based reconstruction [28], [39], [40].…”

“…Raith et al [38] introduced statistical shape representation with anatomy-related topology to reconstruct the missing parts. In clinical studies, mirror-image-based 3D templates for mandibular and maxillary reconstruction have been used to ensure symmetrical reconstruction [28], [39], [40]. However, these models do not evaluate the difference between preoperative and postoperative facial appearance.…”

“…Based on the decision-making trends in conventional manual planning, we introduced two shape descriptors to evaluate the shape of the mandible after reconstruction of a wide resection area, regardless of individual differences in mandibular shape, by referencing shape evaluation indices for chin reconstruction proposed in previous studies [14] and a symmetric transformation approach previously used for reconstruction of mandibular defects [28], [39], [40]. Because surgeons emphasize the restoration of facial appearance, shape distance E s was introduced as an index to quantify the difference in local shape between the patient's original mandible and the reconstructed mandible.…”

Stereolithography

“…Medical applications of SLA are not limited to the fabrication of implants, prostheses, or other medical devices, but drug delivery systems such as micro-needles, capable of administering drugs by painlessly penetrating the skin [78], or 3D printed tablets for individual dosage [77]. Middle row: SEM images of SLA printed microneedle structures for transdermal drug delivery, modified and reprinted from [78].…”

Utilização de prototipagens em cirurgia e traumatologia bucomaxilofacial: relato de casos

“…Esses modelos são confeccionados a partir de exames de imagens tomográficas ou ressonâncias magnéticas no formato DICOM (Digital Imaging and Comunications in Medicine) e impressos com o sistema CAD (Computer Aided Design). Essa interação possibilita a criação de uma estrutura tridimensional que representa um modelo físico do paciente com estrutura anatômica óssea muito semelhante à natural, que, com a espessura milimétrica dos cortes tomográficos, determina a fidelidade do biomodelo impresso tridimensionalmente 3,4 . Para que seja possível a confecção desses modelos, existem duas técnicas: a subtrativa e a aditiva.…”