See how the Geometric Modelling Library has been used to solve complex geometry problems in the field of maxillofacial reconstruction.
Orbital floor reconstruction
GML plays a role in the development of specialist software designed to ease surgical complexity.
GML plays a role in the development of specialist software designed to ease surgical complexity. Working with anaplastologists and maxillofacial prosthodontists from around the world, the GML is being used to develop software that makes the design and production of custom-fit prostheses easier. One example is in the design of full and partial orbital floors. Here, the skull is initially modelled in 3D from CT data. The clinician can then virtually 'clean up' the damaged orbital area to improve 3D visibility and simplify the task of designing a replacement orbital floor component.
GML can then be used to determine missing bony areas and to either digitally design a new floor, or indeed a mirror of the floor of the other eye, as pictured. STL output ensures compatibility with all major manufacturing methods.
Accurate relocation of the jaw in surgery
The re-positioning of the jaw through surgery is used to correct for under bite and over bite as well as for the canted jaw. Current practice typically sees the clinician re-aligning the teeth using braces to achieve best alignment. Once achieved, stone models of the upper and lower jaws are cast, placed in a dental articulator and relocated, by a trained practitioner, into their desired post surgical position. From this position, a dental wafer or 'splint' is cast, typically using acrylic. This process is highly skilled and time consuming, especially when multiple candidate alignments are required.
In theatre, the surgeon can make the bony cuts freeing the jaw(s) for movement. The jaw(s) can then be relocated to their new relative positions with reference to the cast wafers to ensure accurate alignment. While the jaw heals, the new alignment is maintained by the cast wafer.
The GML has been used to digitise wafer production and to replace the slow manual process. Having digitised the stone models using Renishaw's dental CAD/CAM scanning system, the GML allows the writing of routines to automatically move the upper and lower jaws into a closed position. This position can then be easily fine-tuned to the surgeon's requirements. Having positioned the jaws, a wafer can be automatically generated from the bite of the jaws.
Having generated a wafer, holes or knobs can be added to the outside edges, allowing the wafer to be securely fastened to the patient's jaws, and also to allow the patient to temporarily remove the wafer for cleaning and eating.