Condylographic evaluation in patients for orthognathodontic treatment: Study of the quantity of movement in opening and closing in non-dysfunctional patients

Purpose: CADIAX 2 compact is a computerized axiograph capable of producing axiograms of three-dimensional mandibular movements. This technology is considered accurate and precise to measure the horizontal condylar inclination (HCI) and the Bennett angle and allows the processing of curve data through software and the calculation of significant numerical parameters for the formulation of observations of clinical interest. In this preliminary study, measurement were carried out non-dysfunctional patients applying for orthodontic treatment in order to verify the variability of the curves and intercept any temporomandibular dysfunction before treatment. Materials and Methods: 19 patients applying for orthodontic treatment aged between 13 and 24 recruited at the orthodontic ward of IRCCS Ca' Granda Policlinico Hospital Foundation of Milano. Patients with a history of systemic arthropathies or arthritis, postural pathologies, history of facial trauma, previous orthognathic treatment of prosthetic rehabilitations, history of pian or 'temporomandibular dysfunction were excluded. Were also excluded patients who complained about pain an physical examination, joint noises and maximum opening <40 mm. The CADIAX compact 2 system was used for arbitrary recordings. This means that the registration of the movement of the mandibular joint was made on one point of the axis anatomically identified hinge. The reference coordinates of the system originate hum the central point between the condyles, where the hinge axis, in the zero (centric) position, intersects with the median-sagittal plane. A kinematic face bow (Condylograph) was used for the recordings. All the recordings in their entirety, including the preparation phases and the determination of the hinge axis, were performed by the same operator. A complete axiographic exam was performed but a selection of non-guided open/close curves was tracked for the analysis. Each record therefore included: 1) Electronically recoded jaw movement tracks; 2) Measurement of the condylographic position (CPM); 3) X/ Y/ Z coordinates of the tips of the cusps of the teeth of the mandible. The registration data was exported to GAMMA Dental Software and subsequently processed with CADIAX Analyzer. For each curve, the parameter of the amount of movement, intended as the maximum excursion distance of the curve, has been noted. The data concerning the amount of total movement express in mm for the two condyles were extrapolated and compared with the average values reported in the Iiterature. A value equal to 10 ± 2 mm has been defined as normal. Therefore, with values lower than 8 mm we will speak of a limitation of movement (hypomobility) and for values higher than 12mm will speak of hypermobility. Results and Conclusions: In our sample, changes in condylar mobility on one side of bilaterally were detected in 8 patients. Although this investigation was performed in patients who were not frankly dysfunctional, our data show sub-clinical alterations of the condylar dynamics. In conclusion, non-guided open/close curves were selected m representation of habitual function and our results proved for a slightly inferior average distance than expected. Results from this preliminary study should be verified in a larger sample, however it is reasonable to state that the condylographic examination could intercept risk conditions of temporomandibular dysfunction in the treatment phase and m allows further diagnostic investigations in the gnathological field.