A Positional Analyzer for Measuring Centric Slide

Centric relation (CR) has been considered mainly as a position posterior to habitual occlusion or maximum intercuspation (MI). Awareness of the tooth contacts relationship in centric relation position of the mandible and diagnosing the case from this position is essential to consistently select treatment plans that will allow to treat to or very near to centric relation occlusion. Centric slide and other occlusal relationships are conceived of as positions, which can be studied in three dimensions. Clinically, the difference between the two occlusal positions namely CR and MI (centric slide) can easily be determined, but for a more precise evaluation of its length and directions, an occlusal analysis on articulator mounted casts is necessary. Study was under taken on the mounted casts of ten subjects on a semi adjustable articulator to which a stylus and recording table was devised and attached for measurement of CR-MI slide in the three planes namely anterior-posterior, medio-lateral and superior-inferior. It was found that there was a displacement from CR to MI (centric slide) in all the three planes and numerically the mean slide was 0.688 ± 0.623, 0.261 ± 0.627 and 0.127 ± 0.541 mm in the antero-posterior, medio- lateral and superior-inferior directions respectively. The stylus and table attachment may be an accurate indirect method to measure positional changes of the condyle in 3D.