1. Preliminary Evaluation of Virtual Simulation of Dental Contacts
on Edentulous Tooth Arrangements
Carolyn Kincade, Fari Karimi-Boushehri, Daniel Alto, Kieran Armstrong , Ian Stavness, Martin Osswald, Suresh Nayar, John Wolfaardt
Excursion Virtual islands Analogue Islands Common Islands Virtual Cusp Surface Analogue Cusp Surface Common Cusp Surface
3.00_4.00 Right 2 2 2 2 2 2
METHODS
A denture set up was completed in the conventional manner and verified clinically. The
occlusal contacts were evaluated using conventional articulating paper. The analogue
occlusal markings were then compared against results achieved with the Artisynth as
described by Stavness, et al. (2015).
The maxillary and mandibular denture set up was articulated and mounted (fig. 1) and a
conventional articulator (Hanau™ Modular Articulator: Whip Mix Corp Louisville, KY USA).
The mounted casts were scanned (ShapeGrabber Inc, Ottawa ON) and transferred to
Artisynth (fig. 2). To complete the comparison a process was developed to digitize the
conventionally obtained occlusal markings and transfer them in the virtual planning
software (Magics: Materialise Technologielaan, Leuven Belgium). The conventional
occlusal contact points were identified using occlusal ribbon in the conventional manner
(figs. 3 & 4). The occlusal ribbon markings were waxed, extruding the marked area to
increase the height while maintaining the width and integrity of the marking (fig. 5). The
extruded markings or occlusal islands were scanned, resulting in digital islands which
correspond to the occlusal contacts obtained with the articulating paper (fig. 6).
Lateral and protrusive excursions were divided into individual millimeter increments on
the conventional articulator. The articulator was scanned at the start position to the end
of the excursive movement (stop position).
Comparison of the conventional occlusal contacts points and those obtained with the
Artisynth were completed utilizing Magics (Materialise Technologielaan, Leuven Belgium).
Occlusal contacts areas were then compared by identifying and comparing the virtual and
analogue islands obtained with the respective articulators. The number of virtual islands
and analogue islands, common islands, the virtual and analogue cusp surface areas, and
common cusp surface areas were then recorded (Table 1).
RESULTS
The conventional articulator identified two contact points or islands, one on tooth 16 and
one on tooth 17 (fig. 4). The Artisynth identified two contact points on the 16 and one on
the 17 (fig. 7). The numbers of virtual, analog and common islands were the same on each
articulator. Each tooth was divided into quadrants; the mesio-buccal cusp, diso-buccal
cusp, mesio-lingual cusp and disto-buccal cusp (figs. 8 & 9). The cusp surface areas were
also calculated. Both articulators identified two cusp surface areas on the 16 and 17 disto-
lingual cusps. The Artisynth and the conventional articulator had common occlusal islands
and common cuspal surfaces areas.
INTRODUCTION
A dental articulator is a device used by dental technicians to which casts of a patient’s
maxilla and mandible are related and fixed as recorded by a clinician during a jaw relation
recording (JRR). The articulator is used to achieve reproducible jaw positions and
postures, and to evaluate function.
Traditional methods are extremely manual, as tasks are performed by hand while
evaluations are done by eye. The creation of a digital articulator can enhance the ability
for technicians to utilize digital pathways. Computer Aided Design (CAD) can measure and
evaluate fabrication steps throughout the process, creating more consistent results which
better adherence to clinical standards. When fabricating complete upper and lower
dentures, CAD can be a useful tool; the addition of a virtual articulator would allow the
user to digitally perform dynamic jaw excursions and make digital rather than manual
adjustments. The development of a digital articulator could allow full digital denture
setups and fabrication to be completed and evaluated with reduced need for
conventional laboratory methods.
Stavness et al. (2015) demonstrated accurate occlusal contact areas in fully dentate casts
while using a digital articulator based on a biomechanical modelling software, Artisynth.
The application of the Artisynth could be of great benefit in the fabrication of dental
prostheses with the potential to decrease fabrication times, provide patients and
clinicians with more reliable outcomes, fewer manual adjustments, and reduced
treatment time.
OBJECTIVE
The aim of this pilot project was to validate the occlusal contact points detected by the
Artisynth with occlusal contacts identified by a conventional articulator on a complete
upper and lower denture tooth arrangement.
DISCUSSION
Preliminary comparisons suggest that results achieved with the Artisynth match those observed with the conventional
articulator. The comparisons were done visually and will need to be calculated in the future to determine if the occlusal contact
points are identical. The Artisynth depends on the accurate JRR’s alignment of the maxillary and mandibular casts as any error
would be perpetuated in Artisynth.
CONCLUSION
The digital articulator can enable technicians to utilize digital pathways in the fabrication of dental prostheses. The results of this
study suggest that the Artisynth based virtual articulator could be a viable tool in fabrication of edentulous dentures, eliminating
many analogue steps and simulating them digitally.
Further research and evaluation is required to develop understanding of the program capabilities and role of the Artisynth
in dental prosthesis fabrication.
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Fig. 1 Fig. 2
Fig. 9Fig. 8
Fig. 3 Fig. 5Fig. 4
Fig. 6 Fig. 7
Table 1