Determining the interchangeability of KaVo Protar semi-adjustable articulators using digital image processing and analysis

Objectives: The dental articulator is an instrument that enables the dentist to mount maxillary and mandibular dental casts. It is essential for prosthetic treatment since it demonstrates the spatial relations between the maxilla and mandibula. The articulator allows a communication channel between the dentist and the dental technician. Dental restorations fabricated in the laboratory are mounted using the articulator. Interchangeability of articulators allows mounted casts to be transferred from one articulator to another and thus is highly important in maintaining an accurate three-dimensional relationship.

The objective of this investigation was to evaluate the interchangeability of 22 KaVo PROTAR®evo articulators using digital image processing and analysis.

Methods: Twenty two KaVo PROTAR®evo articulators were evaluated. Two points were marked on central incisors and first molars on the upper and lower models. The relations between the models were recorded using a digital single lens reflex (DSLR) camera with a custom made metal base for standardization. This base assured photos taken from a fixed distance and angle for each articulator. Images were analyzed using ImageJ software. The inter-rater reliability of the measurements was determined by Pearson correlation co-efficient. Interchangeability was determined using two way manova -multivariate analysis of variance.


Results: Pearson correlation co-efficient showed high correlation between the evaluators. Interchangeability in frontal aspect of the X and Y axis resulted in 837.75 µm and 640.35 µm, respectively. Interchangeability in the sagittal aspect of the X and Y axis resulted in 596.60 µm and 336.45 µm, respectively.
Conclusions: The high values recorded here suggest that KaVo PROTAR®evo articulators have low interchangeability.