R_Bibb_Medical_Modelling_The_Application_of_Adv.pdf

180 Medical modelling
6.9.4 Results
Treatment outcome
Both cases responded extremely well to treatment and showed considerable
reduction in scarring. The patients’ masks fi tted well, performed as
intended, and proved equally as effective as those produced by traditional
methods.
Vacuum moulding
The LOM TM model proved an excellent mould and was unaffected by
vacuum forming. The plaster-fi lled SL mould also proved satisfactory. Both
types of mould can be worked with grinding tools should they need to be
altered to produce subsequent masks as treatment progresses. However, it
was noted that the transparent nature of the SL material combined with
the white plaster infi ll made the surface features diffi cult to see clearly. The
layered surface fi nish of neither the LOM TM nor SL mould was transferred
to the vacuum-formed PETG mask.
Accuracy
The accuracy of the scan data is nominally 0.1 mm. As the skin is somewhat
mobile and pliable, the accuracy of the captured data proved to be more
than adequate. SL models are typically accurate to within 0.1 mm of the
data from which they are built and LOM TM models are nominally accurate
to within 0.2 mm. These accuracies proved to be well within the requirements.
For this application, relatively inexpensive CNC machines are
capable of producing satisfactory moulds.
6.9.5 Discussion
The success of this study illustrates the effi cacy of three-dimensional scanning,
CAD and RP for this application. The accuracy of the scan data was
found more than adequate. The non-contact nature of the scanning imposes
less discomfort on patients and eliminates the potential risk of distortion
of soft tissues, which may occur when taking impressions. Therefore, the
method compares favourably with current practice. In addition, the reduction
in anxiety or claustrophobia when taking facial impressions should be
seen as an advantage.
Although this research deliberately utilised readily available, manufacturer
supported equipment and software, the cost of the scanners, associated
software and RP equipment remains considerable, and it may be