Accuracy and precision of occlusal contacts of stereolithographic casts mounted by digital interocclusal registrations
Available online 9 April 2016
Abstract
Statement of problem
Little
peer-reviewed information is available regarding the accuracy and
precision of the occlusal contact reproduction of digitally mounted
stereolithographic casts.
Purpose
The
purpose of this in vitro study was to evaluate the accuracy and
precision of occlusal contacts among stereolithographic casts mounted by
digital occlusal registrations.
Material and methods
Four
complete anatomic dentoforms were arbitrarily mounted on a
semi-adjustable articulator in maximal intercuspal position and served
as the 4 different simulated patients (SP). A total of 60 digital
impressions and digital interocclusal registrations were made with a
digital intraoral scanner to fabricate 15 sets of mounted
stereolithographic (SLA) definitive casts for each dentoform. After
receiving a total of 60 SLA casts, polyvinyl siloxane (PVS)
interocclusal records were made for each set. The occlusal contacts for
each set of SLA casts were measured by recording the amount of light
transmitted through the interocclusal records. To evaluate the accuracy
between the SP and their respective SLA casts, the areas of actual
contact (AC) and near contact (NC) were calculated. For precision
analysis, the coefficient of variation (CoV) was used. The data was
analyzed with t tests for accuracy and the McKay and Vangel test for precision (α=.05).
Results
The accuracy analysis showed a statistically significant difference between the SP and the SLA cast of each dentoform (P<.05).
For the AC in all dentoforms, a significant increase was found in the
areas of actual contact of SLA casts compared with the contacts present
in the SP (P<.05). Conversely, for the NC in all dentoforms,
a significant decrease was found in the occlusal contact areas of the
SLA casts compared with the contacts in the SP (P<.05). The
precision analysis demonstrated the different CoV values between AC
(5.8-8.8%) and NC (21.4-44.6%) of digitally mounted SLA casts,
indicating that the overall precision of the SLA cast was low.
Conclusions
For
the accuracy evaluation, statistically significant differences were
found between the occlusal contacts of all digitally mounted SLA casts
groups, with an increase in AC values and a decrease in NC values. For
the precision assessment, the CoV values of the AC and NC showed the
digitally articulated cast’s inability to reproduce the uniform occlusal
contacts.
Comments