A Positional Analyzer for Measuring Centric Slide

Abstract

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.

Centric slide in different Angle's classes of occlusion

“…In contrast to other studies (Abraham and Veeravalli, 2012;Weffort and de Fantini, 2010;Klar et al, 2003;Utt et al, 1995;Foglio-Bonda et al, 2006), lower values of the centric slide obtained in this study (Table 1) could be explained with different material and methods.…”

“…Smaller amount of the transversal movement (0.13 mm, SD 0.12, Table 1) than in other studies (Abraham and Veeravalli, 2012;Weffort and de Fantini, 2010;Padala et al, 2012) could also be explained with different methodology.…”

“…Most of the textbooks state that slide from the centric occlusion to the maximum intercuspation occur at approximately 90% of people, and on average is 1 mm long (Okeson, 2008). Still, review of literature (Pullinger et al, 1987;Mohlin, 1983;Demisch et al, 1992;Abraham and Veeravalli, 2012;Weffort and de Fantini, 2010;Klar et al, 2003;Foglio-Bonda et al, 2006) reveals different results, mostly because of study methods. Different approaches have been used for measuring the centric slide: directly in the mouth (Pullinger et al, 1987;Mohlin, 1983;Demisch et al, 1992), with conventional radiography (Kydd and Sander, 1961), cone beam CT (Henriques et al, 2012), jaw tracking devices (Foglio-Bonda et al, 2006) and with articulated casts (condyle position indicator) (Abraham and Veeravalli, 2012;Weffort and de Fantini, 2010;Klar et al, 2003).…”

“…Differences in obtained values for centric slide are also expected because of different reference points. For instance Pullinger et al (1987) choose a second premolar for measuring the centric slide, while many studies used sagittal incisal point (Kydd and Sander, 1961;Demisch et al, 1992) or condyle of the articulator (condyle position indicator) (Weffort and de Fantini, 2010;Padala et al, 2012;Abraham and Veeravalli, 2012). Due to condylar rotation, centric slide can have different values at occlusal or condylar level (Foglio-Bonda et al, 2006).…”

Electronic central bearing point as registration method in individuals with and without temporomandibular disorders

“…Other studies refer to the three-dimensional condylar displacement, which also show significant differences of the maximal intercuspal position and the centric relation. [16][17][18].…”