Development and validation of a parametric mandible plate design method

Date
2021-03
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: This study investigated the feasibility and attempted to develop a parametric mandible reconstruction plate design method in order to reduce surgical lead time, improve fit and structural performances. This method includes a CAD template that accepts a range of realistic mandible dimensions as the input. The output is a 3-dimensional mandible reconstruction plate. A reconstruction plate/mandible comparison test was performed on several combinations in order to determine whether the parametric plate provided a suitable alternative to conventional reconstruction plates in terms of fit and structural performance. 37 male and 37 female random mandibles were generated and measured. These measurements were used to create the corresponding parametric plates. The plates were aligned with their mandibles and the Hausdorff distances were recorded. A Finite Element Analysis was performed on the male and female mandibles which exhibited the most curvature, with three common plate configurations in literature. All boundary conditions such as the displacements, supports, muscle force vectors and magnitudes, as well as mandible and plate material properties were taken from literature. The comparison test indicated that the parametric plate provides a reasonable approximation of mandible geometry. The mean mandible plate deviation for lateral short and symphyseal plates was less than 2 mm for the male and female configurations. The mean hemimandible plate deviation was less than 2.6 mm for both the male and female plates. Some bending may be required due to the irregularities in mandible geometry, however significantly less than what is required to shape the commercial straight mandible reconstruction plate. The Finite Element Analysis results indicate that the maximum Von-mises stresses in parametric plate were noticeably lower in all three plate configurations when compared to the commercial straight reconstruction plates. The lowest recorded maximum stress recorded in the parametric plates was in the male symphyseal plate at 102.31 MPa. The highest maximum stress recorded in the parametric plates was in the female hemimandible plate at 623.38 MPa. Whereas the respective stresses in the commercial straight plates were 223.09 MPa in the male symphyseal and 652.25 MPa in the female hemimandible plates. Reaction values were compared with hand calculations as a means of model validation.
AFRIKAANSE OPSOMMING: Hierdie studie ondersoek die vermoeë en probeer om 'n parametriese kakebeen rekonstruksieplaat te ontwikkel om chirurgiese lei tyd te verminder, sowel as die pas en strukturele prestasie te verbeter. Hierdie metode bevat ‘n CAD-sjabloon wat ‘n reeks realistiese onderkaakafmetings aanvaar as die insette. Die uitset is 'n driedimensionele onderkaakrekonstruksieplaat. 'n Rekonstruksieplaat / kakebeen vergelykingstoets is op verskeie kombinasies uitgevoer om vas te stel of die parametriese plaat 'n geskikte alternatief vir konvensionele rekonstruksieplate bied wat pas en strukturele prestasie betref. 37 manlike en 37 vroulike kakebene is gegenereer en gemeet. Hierdie metings is gebruik om die ooreenstemmende parametriese plate te skep. Die borde is in lyn gebring met hul kakebene en die Hausdorff-afstande is aangeteken. 'n Eindige elementanalise-simulasie is uitgevoer op die manlike en vroulike onderkaak wat die meeste kromming vertoon, met drie algemene plaatkonfigurasies in die literatuur. Alle randtoestande soos verplasings, drade, spierkragvektore, groottes, onderkaak en plaatmateriaal-eienskappe is uit die literatuur geneem. Die vergelykingstoets het aangedui dat die parametriese plaat 'n redelike benadering van die kakebene geometrie bied. Die gemiddelde afwyking van die rekonstruksieplaat vir laterale kort en simfisiese plate was minder as 2 mm vir die manline en vroulike konfigurasie. Die gemiddelde afwyking van die halwe-kakebeen plaat was minder as 2.6 mm vir beide die manlike en vroulike plate. Moontlike buiging kan nodig wees as gevolg van die onreëlmatighede in die onderkaakgeometrie, maar aansienlik minder as wat nodig is om die kommersiële onderkaakrekonstruksieplaat te vorm. Die resultate van die eindige elementanalise dui aan dat die maksimum Von-mises spanning in die parametriese plaat opvallend laer was in al drie plaatkonfigurasies in vergelyking met die kommersiële reguit rekonstruksieplate. Die laagste aangetekende maksimum spanning wat in die parametriese plate aangeteken is, was in die manlike simifisiese plaat op 102.31 MPa. Die hoogste maksimum spanning wat in die parametriese plate aangeteken is, was in die vroulike halwe-kakebeen plaat op 623.38 MPa. Terwyl die oderskeie spannings in die kommersiële reguit plate 223,09 MPa in die manlike en simfisiese was en 652.25 MPa in die vroulike halwe-kakebeen plate. Reaksiewaardes is vergelyk met handberekeninge as 'n middel vir model validering.
Description
Thesis (MEng)--Stellenbosch University, 2021.
Keywords
Mandible, Patient-specific, Implant, Parametric devices, UCTD, 3-dimensional ..., Mandible -- Surgery
Citation