Surgical Splint Design via 3D Dental-Facial Model Fusion
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Solution Overview
Problem
Current methods for surgical planning in orthognathic surgery are time-consuming and lack accuracy due to the inability of 3-D CT models to accurately represent the patient's dentition, often obscured by orthodontic metal brackets, dental fillings, or prosthesis, requiring the use of metal fiduciary markers for alignment.
Innovation Solution
A method combining 3-D facial and dental computer models, where a 3-D facial model of the skull is aligned with a 3-D dental model obtained through optical scanning of the dentition, eliminating the need for metal fiduciary markers and providing a composite model for creating a surgical splint that accurately represents both bone structure and dentition in a planned post-operative configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a 3-D CT model is used to represent the patient's dentition, then the bone structure is accurately represented, but the dentition is obscured or includes artifacts due to metal brackets, fillings, or prosthesis
Solution Approach 1:
The patent divides the dental imaging process into two separate segments: (1) obtaining a 3-D CT model of the patient's skull and bone structure, and (2) obtaining a separate 3-D dental model by scanning a plaster cast of the dentition. This segmentation allows each model to be optimized for its specific purpose without interference from metal artifacts, resolving the contradiction between accurate bone representation and artifact-free dentition representation.
Solution Approach 2:
The patent introduces a plaster cast as an intermediary medium between the patient's actual dentition and the 3-D scanning process. By scanning the plaster cast rather than the dentition directly, the system eliminates metal artifacts while still capturing accurate dental anatomy. The plaster cast serves as a mediator that translates the complex problem of scanning metal-containing dentition into a simpler artifact-free scanning process.
2Manufacturing precision
If metal fiduciary markers are used to align the dental computer model with the CT model, then the composite model can be formed, but the process becomes time-consuming
Solution Approach 1:
The patent extracts and eliminates the metal fiduciary markers from the alignment process. Instead of using physical metal markers that require placement, detection, and manual alignment, the system uses automated software-based alignment algorithms that process the 3-D models directly. This extraction of the problematic element (metal markers) resolves the contradiction between achieving precise alignment and avoiding time consumption.
Solution Approach 2:
The patent replaces the mechanical alignment system (physical fiduciary markers and manual positioning) with a digital/software-based alignment system. The mechanical process of placing and physically aligning metal markers is substituted with computational algorithms that automatically register and align the 3-D facial and dental models, significantly reducing the time required while maintaining or improving alignment precision.
3Measurement precision
If a plaster cast of the dentition is scanned instead of the dentition itself, then the virtual dental model is not obscured by metal brackets or fillings, but an additional scanning step is required
Solution Approach 1:
The patent creates a copy (plaster cast) of the patient's dentition that replicates the dental anatomy without the interfering metal components. This copy allows the scanning process to capture accurate dental geometry without artifacts from brackets or fillings. The plaster cast serves as a faithful replica that enables artifact-free scanning while maintaining complete dental information, resolving the contradiction between measurement precision and process complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the creation of custom surgical splints that accurately guide the repositioning of the maxilla and mandible during surgery, improving the precision and efficiency of orthognathic surgical planning and execution.
Implementation Method 1
obtaining a 3-D optical scan of a surface geometry of the patient's dentition
Data Source
Figure 1A~1E
Figure 2A~2E
Figure 3A~3E
AI summary
A method of pre-operatively forming a surgical splint configured to receive a patient's dentition can include combining a 3-D facial computer model and a 3-D dental computer model. The method includes the step of obtaining a 3-D facial computer model of at least the patient's maxilla, mandible, and dentition from a CT scanner and the step of obtaining a 3-D dental computer model of the patient's dentition with an optical scanner. The 3-D dental computer model is then combined with the 3-D facial computer model to form a composite virtual model. The composite virtual model can be manipulated into a planned post-operative shape, and a surgical splint can be custom constructed to match the planned post-operative shape. The surgical splint can be configured to receive the patient's dentition.