New dimensions in tooth implant and transplantation

Wismeyer, D. [Promotor]Merkesteyn, J.P.R. [Promotor]Hassan, B.A. [Copromotor]Tahmaseb, A. [Copromotor

A novel approach for custom three-dimensional printing of a zirconia root analogue implant by digital light processing

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

A patient specific biomechanical analysis of custom root analogue implant designs on alveolar bone stress:A finite element study

Objectives. The aim of this study was to analyse by means of FEA the influence of 5 custom RAI designs on stress distribution of peri-implant bone and to evaluate the impact on microdisplacement for a specific patient case. Materials and Methods. A 3D surface model of a RAI for the upper right canine was constructed from the cone beam computed tomography data of one patient. Subsequently, five (targeted) press-fit design modification FE models with five congruent bone models were designed: “Standard,” “Prism,” “Fins,” “Plug,” and “Bulbs,” respectively. Preprocessor software was applied to mesh the models. Two loads were applied: an oblique force (300 N) and a vertical force (150 N). Analysis was performed to evaluate stress distributions and deformed contact separation at the peri-implant region. Results. The lowest von Mises stress levels were numerically observed for the Plug design. The lowest levels of contact separation were measured in the Fins model followed by the Bulbs design. Conclusions. Within the limitations of the applied methodology, adding targeted press-fit geometry to the RAI standard design will have a positive effect on stress distribution, lower concentration of bone stress, and will provide a better primary stability for this patient specific case

Computer-assisted template-guided custom-designed 3D-printed implant placement with custom-designed 3D-printed surgical tooling: an in-vitro proof of a novel concept

Objectives: The aim of this study was to introduce a new concept for computer-assisted template-guided placement of a custom 3D-designed/3D-printed implant with congruent custom 3D-designed/3D-printed surgical tooling and to test the feasibility and accuracy of this method in-vitro. Materials and methods: One partially edentulous human mandibular cadaver was scanned with a cone-beam computed tomography (CBCT) system and intra-oral scan system. The 3D data of this cadaver were imported in specialized software and used to analyse the region of a missing tooth. Based on the functional and anatomical parameters, an individual implant with congruent surgical tooling and surgical guided template was designed and 3D-printed. The guided osteotomy was performed, and the custom implant inserted. To evaluate the planned implant position in comparison with the placed implant position, the mandible with implant was scanned again with the CBCT system and software matching was applied to measure the accuracy of the procedure. Results: The angular deflection with the planned implant position was 0.40°. When comparing the 3D positions of the shoulder, there is a deviation of 0.72 mm resulting in an apical deviation of 0.72 mm. Conclusion: With the use of currently available technology, it is very well feasible to create in a virtual simulation a custom implant with congruent custom surgical tooling and to transfer this to a clinical setting. However, further research on multiple levels is needed to explore this novel approach

Autotransplantation 2.0:Considerations, results and the latest techniques

Autotransplantation is a valuable technique offering a physiological type of tooth replacement to patients with missing teeth. Teeth with open apices (50-75% apical closure) will regenerate with vitality following autotransplantation. The success rate following an autotransplantation is 82%. The remaining 18% can usually still be treated successfully with a simple additional treatment. The tooth survival rate 10 years after autotransplantation is higher than 90%. The use of 3D techniques makes it possible to create a pre-operative replica of the donor tooth. With this, a new alveolus can be prepared at the transplant site even before extraction. This technique reduces the extra-alveolar time for the donor tooth and minimises the possibility of iatrogenic damage. This results in a streamlined procedure, enabling better planning with better results

A novel approach for computer-assisted template-guided autotransplantation of teeth with custom 3d designed/printed surgical tooling. An ex vivo proof of concept

Purpose: The aim of this study was to introduce a novel method for accurate autotransplantation with computer-assisted guided templates and assembled custom-designed surgical tooling and to test the feasibility and accuracy of this method ex vivo. Materials and Methods: A partially edentulous human mandibular cadaver was scanned with a cone-beam computed tomography (CBCT) system and an intraoral scan system. The 3-dimensional (3D) data of this cadaver were imported into specialized software and used to analyze the region of the recipient site and the donor tooth was selected. Subsequently, congruent to the donor tooth, custom surgical tools and a surgical guided template were designed and 3D printed. The guided osteotomy was performed and the donor tooth was transplanted. To evaluate the planned position of the donor tooth in relation to the position of the transplanted donor tooth, the mandible with the transplanted donor tooth was rescanned with the CBCT system and software matching was applied to measure the accuracy of the procedure. Results: The angular deflection of the transplanted donor tooth in relation to the planned donor tooth position was 3.1°. When comparing the 3D positions of the shoulder, there was a deviation of 1.25 mm and an apical deviation of 0.89 mm. Conclusion: With the use of currently available technology, it is feasible to accurately plan and create in a virtual simulation a donor tooth position with congruent custom surgical tools and to transfer this to a clinical setting with 3D printing. However, further research on multiple levels is needed to explore this novel approach