Ales Celar

Computerized Axiography: Principles and Methods

This paper reviews earlier methods for the analysis of mandibular movement and gives a detailed account of state-of-the-art procedures. Special emphasis is given to computerized axiography and the application of this method to the diagnostics of the temporomandibular joint (TMJ). The article discusses the advantages of computerized axiography over the mechanical device and points out the limitations of the axiographic method. One major advantage of the computerized system is having the enlarged diagram of tracings on the computer screen. This means that small changes such as initial disk displacements can be diagnosed more readily than with the mechanical device.

Comparison of magnetic resonance tomography with computerized axiography in diagnosis of temporomandibular joint disorders

This study compared the accuracy of two noninvasive methods, computerized axiography and magnetic resonance tomography (MRT), in diagnosing temporomandibular joint (TMJ) disorders. Forty-seven subjects underwent axiography and subsequent assessment of the TMJ by MRT. The statistical analysis referred to the correlations of the most relevant clinical diagnoses, i.e., no appreciable disease, disk displacement with reposition, disk displacement without reposition, morphologic alterations, and hypermobility of the condyle. In 70% of the disk-displacement-with-reposition and disk-displacement-without-reposition patient groups, axiography and MRT gave the same information. In other patient groups, the axiography findings agreed with the MRT findings in 45% of the cases. It was concluded that although a large percentage of morphologic alterations could be detected by MRT, axiography determined the dysfunctional dynamics more clearly.

Orthopedic Jaw Movement Observations. Part I: Determination and Analysis of the Length of Protrusion

An analysis and quantitation of protrusive and retrusive mandibular movement is provided. This report is one study along with four other parts analyzing the mandibular opening movement, the transversal shift during protrusion and retrusion, the mediotrusive movement and mastication. Protrusive movements of 225 individuals (180 patients, 45 volunteers) were analyzed using computerized axiography. Investigating both asymptomatic volunteers and patients with abnormal joint mobility helps to improve evaluation of these abnormalities. With the aid of diagnostic computer software, the length of the pathways was measured and the characteristics of the curves were analyzed. An average group was defined based on the values found in asymptomatic individuals, comprising 50% of our volunteers. The interquartile range for the male volunteers was 8.79-12.27 mm for the right joint and 9.43-12.93 mm for the left joint; for female volunteers it was 8.32-10.64 mm and 9.2-11.26 mm, respectively.

An Analysis of Hinge Axis Translation and Rotation During Opening and Closing in Dentulous and Edentulous Subjects

In order to evaluate the influence of interocclusal environment, condylar movement was investigated by computerized axiography. The sample consisted of 50 dentulous and 50 edentulous Caucasians. The mean length of translation at maximum opening in dentulous subjects was 16 mm, while edentulous subjects showed an average of 11 mm. The mean angle of hinge axis rotation at maximum opening was 30 degrees in dentulous subjects and 17 degrees in edentulous subjects. The mean length of translation and the rotation of hinge axis in opening and closing movements was smaller in edentulous subjects than in dentulous ones. In opening and closing movement of edentulous subjects, the length of translation and the rotation value revealed no significant correlation with age or duration of upper and lower prosthesis. No significant difference was shown between edentulous and dentulous subjects on translative quantity in protrusive movement.

Orthopedic Jaw Movement Observations. Part III: The Quantitation of Mediotrusion

The objective of this series is to observe and analyze movements of the temporomandibular joint (TMJ). With the information from these studies, orthopedic standards for jaw movements will be established in further investigations according to the neutral-zero method used in general orthopedics. Any restricted range of motion can thus be defined as a deviation from these standards. Direct interpretation and objective evaluation of joint functions has major practical implications. With the aid of computerized axiography, mediotrusive movements of 48 asymptomatic volunteers and 66 jaw patients were evaluated. The movements performed were either free or guided. The mean curve lengths, as well as the Bennett angles at 3 mm and at the end point were recorded. An average group was defined, containing the values of 50% of all volunteers. The interquartile range was calculated for lengths of mediotrusive movements as well as for Bennett angles. The average range of free mediotrusive movement for female volunteers was 11.06-11.98 mm (mean 11.55 mm) on the right side and 10.47-11.75 mm (mean 11.24 mm) on the left side. Male volunteers showed an average range of 10.23-11.54 mm (mean 11.1 mm) on the right side and 10.24-11.73 mm (mean 11.12 mm) on the left side. The values for female patients amounted to 9.95-1.66 mm (mean 10.8 mm) on the right side and 9.75-11.28 mm (mean 10.55 mm) on the left side. The average range for male patients was 9.06-9.71 mm (mean 9.54 mm) on the right side and 9.17-10.23 mm (mean 9.73 mm) on the left side. The average range for Bennett angles at maximum excursion in free mediotrusive movement was between 0.41 and 5.89 degrees (mean 4.43 degrees) in the volunteers on the right side and between 2.45 and 10.07 degrees (mean 6.87 degrees), respectively, on the left side. The values for patients amounted to 0.19-12.65 degrees (mean 6.93 degrees), on the right side and 1.71-14.15 degrees (mean 6.73 degrees) on the left side.

The Effect of Occlusal Splint Therapy on Different Curve Parameters of Axiographic TMJ Tracings

Computerized axiography was used as an objective instrumental method of evaluating the response of patients with temporomandibular joint (TMJ) symptomatology to occlusal splint therapy. Diagnosis was performed in a standardized manner by systematically analyzing TMJ path tracings obtained by computerized axiography. Thirty-six patients were axiographed before and after therapy with full-arch occlusal stabilizing appliances, followed by assessing the effect of therapy on various path curve parameters. The data obtained for the patient group treated with splints was compared to that of six patients also axiographed, but left untreated for a period of six weeks before a second TMJ tracing was obtained. The results show that splints have a certain effect on reciprocal TMJ clicking (response rate 67%). Retral stability and path characteristics are also substantially improved (response rates 44% and 40%). Less influence was noted on hypomobile joint paths (response rate 29%), the quality of movements (response rate 28%) and Bennett angle values (response rate 23%). Patients with disk displacements without reduction were not treated with splints, they underwent surgery. Their results will be reported later. By contrast, TMJ tracings in the control group remained essentially unchanged.

Cephalometric differentiation between vertical and horizontal malocclusions in 122 Europeans using the Denture Frame Analysis and standard measurements

This study evaluated the ability of some cephalometric measurements to differentiate between horizontal and vertical malocclusions and normal occlusion. Based upon the Angle classification and the vertical incisor overbite, 122 randomly selected subjects were assigned to 3 horizontal and 3 vertical groups: neutrocclusion, distocclusion, mesiocclusion as well as open bite, normal overbite, and deep bite. Evaluation of the lateral cephalograms was based on Denture Frame Analysis and cephalometric standard measurements (SNA, SNB, ANB, Wits appraisal, Björk polygon, overbite depth indicator, incisor inclination, incisor protrusion, facial height ratio). The statistical evaluation assessed the ability of the measurements to show significant differences between the individual horizontal and vertical groups. Using Denture Frame Analysis, all vertical groups could be differentiated by the occlusomandibular angle (OP-MP) and all horizontal groups by the angle between the A-B plane and the mandibular plane as well as by the inclination of the upper incisors to the A-B plane with statistical significance (p<0.05). Among the standard measurements, the Wits appraisal was the only one to show differences between all horizontal groups with statistical significance. None of the tandard measurements could fully differentiate the vertical groups. The above measurements from the Denture Frame Analysis distinguished the types of malocclusion in anteroposterior and vertical direction including significant distinction between the neutrocclusion group and the malocclusion groups. Therefore a cephalometric classification was feasible in terms of hyper- and hypodivergence as well as of a mesial or distal dentofacial relationship.ZusammenfassungDie vorliegende Arbeit untersuchte das Diskriminierungsvermögen einiger kephalometrischer Messungen bei vertikaler und horizontaler Malokklusion bzw. Regelbiß. Es wurden 122 randomisiert ausgewählte Patienten anhand der Angle-Klassifizierung und des Schneidezahnüberbisses in je drei horizontale und drei vertikale Gruppen eingeteilt: Neutralokklusion, Distalokklusion, Mesialokklusion bzw. offener Biß, Regelüberbiß und Tiefbiß. Zur Auswertung der Fernröntgenseitenbilder wurden die Denture-Frame-Analyse und kephalometrische Standardmessungen verwendet (SNA, SNB, ANB, Wits appraisal, Björk-Summenwinkel, Overbite Depth Indicator, Inklination und Protrusion der Schneidezähne, Gesichtshöhenverhältnis). Statistisch wurde untersucht, inwieweit die genannten Messungen signifikante Unterschiede zwischen den einzelnen horizontalen bzw. vertikalen Gruppen anzeigten. Bei der Denture-Frame-Analyse konnten alle vertikalen Gruppen durch den Okklusomandibularwinkel (OP-MP) und alle horizontalen Gruppen durch den Winkel zwischen der A-B-Ebene und der Mandibularebene sowie der Inklination der oberen Schneidezähne zur A-B-Ebene statitistisch signifikant differenziert werden (p<0,05). Unter den Standardmessungen war das Wits appraisal die einzige, welche signifikant zwischen allen horizontalen Gruppen unterschied. Keine der untersuchten Standardmessungen konnte die vertikalen Gruppen vollständig differenzieren. Die genannten Messungen der Denture-Frame-Analyse ermöglichten eine Zuordnung der Malokklusionstypen in ein anteroposteriores und vertikales Schema mit signifikanter Trennung zwischen Neutralokklusionsgruppe und Malokklusionsgruppen. Dies erlaubte eine kephalometrische Zuordnung im Sinne von Hyper- und Hypodivergenz bzw. Mesial- und Distalbeziehung.

Mandibular reference position: chin-point guided closure vs. final deglutition.

The study investigated two mandibular positions based upon computerized axiography recordings of hinge axis movements of 262 subjects. Next to the well-known guided closure position RP (reference position by chin-point guidance), the position of final deglutition (FD) was quantified. FD represented the hinge axis position at the end of the swallowing movement. The results elicited average linear distances of 0.32 +/- 0.43 mm on the right and 0.33 +/- 0.40 mm on the left side between both positions in the sagittal plane. The average distance in the frontal plane was 0.02 mm (right) and 0.04 mm (left). Approximately 46 per cent of FD recordings were found anterior and inferior to RP, and showed significant difference to posterior and anterior-superior FD recordings. The replicability of both positions was tested on 53 subjects and averaged 0.04 mm (FD) and 0.09 mm (RP). Average deviations of repeated recordings within the subject ranged from 0.07 to 0.47 mm (FD) and 0.07 to 0.57 mm (RP) for each spatial direction. The results of this study showed a relative coincidence of an average FD and RP Variation of FD in anterior inferior direction questioned the clinical reliability of FD to reassure the guided closure position.