Condylar Path Research Articles

Preliminary clinical study of the accuracy of a digital axiographic recording system for the assessment of sagittal condylar inclination

ObjectivesThe aim of this study was to clinically evaluate the accuracy of a digital axiographic recording system in tracing the sagittal condylar inclination. MethodsAn axiographic examination that records the sagittal condylar path during protrusive/retrusive movement was performed on ten patients. Each subject was registered five different times by two different systems: 1) the Cadiax Gamma Diagnostic 4 computerized system as the control; 2) the Zebris Jaw Motion Analyser+ Optic System as the tested digital axiographic recording system. The records obtained allow to calculate the kinematic terminal transverse horizontal axis and the sagittal condylar inclination (SCI) at 3 and 5 mm along the pro-retrusive path. A linear mixed model was used to analyze if there was a statistically significant difference between the two systems. ResultsThe mean left SCI value recorded by Zebris system were 49.81 ± 10.64° at 3 mm, 48.10 ± 11.04° at 5 mm, while the values recorded by Gamma system were 55.16° at 3 mm, 52.18° at 5 mm. The mean right SCI value recorded by Zebris system were 54.53 ± 10.26° at 3 mm, 51.85 ± 8.55° at 5 mm, while the values recorded by Gamma system were 49.68° at 3 mm, 48.23° at 5 mm. Linear mixed model showed no significant statistical difference between the two systems. ConclusionsBased on preliminary results, the Zebris Jaw Motion Analyzer+ Optic System demonstrates comparable accuracy to the Cadiax Gamma Diagnostic 4 when measuring sagittal condylar inclination. Clinical significanceThe digital axiographic recording system enables to evaluate sagittal condylar inclination and to adjust virtual articulators in a digital workflow.

Intraindividual Left-Right Side Differences of Sagittal Condylar Inclination (SCI) in Different Skeletal Classes.

(1) Background: The temporomandibular joint (TMJ) is the most complex and one of the most important joints in the human body due to its essential roles in mastication, swallowing, breathing and speech. Several instruments have been used to track mandibular movements and register the characteristic parameters of the TMJ, among which condylography instruments are validated for the accurate clinical registration of the condylar path. Sagittal condylar inclination (SCI) is one of the most important parameters, together with the Bennett angle and the immediate side shift, used for articular settings in the process of oral rehabilitation. The aim of the present study was to evaluate the differences between the left and right SCI and to assess whether the differences were statistically significant for skeletal class, age, gender, dentate status, TMJ pathology or parafunctional habits. (2) Methods: One hundred and forty consecutive patients, fully dentate or partially edentulous, and with angle class I, II and II, were recruited. Their left and right SCIs were determined with an ultrasonic jaw tracking device. Each subject had to make three protrusive movements and three right and left laterotrusive movements. The software calculated the SCI from the mean of the protrusive movements. (3) Results: The mean values obtained for the right and left SCI were 34.68° (±12.44°) and 34.94° (±13.23°), respectively, with no statistically significant differences between the left and right values for gender, dentate status, TMJ disorders or parafunctional habits. Skeletal class III subjects registered lower SCI means, which were statistically significant for the left SCI. (4) Conclusions: For an optimal functionalization of prosthetic restorations and for an ideal treatment plan, the registration of both the left and right paths of the condyles and the articular disc should be taken into consideration.

Complicated Relationships between Anterior and Condylar Guidance and Their Clinical Implications-Comparison by Cone Beam Computed Tomography and Electronic Axiography-An Observational Cohort Cross-Sectional Study.

A complex prosthodontic treatment is believed to be more successful when the condylar path is replicated using the articulator. However, there is an ongoing major disagreement between the researchers as the exact relationship between the posterior and anterior determinants has not been clear. The purpose of this study was to investigate whether the protrusive movement of the mandible does correlate with the temporomandibular joint (TMJ) anatomy or with incised features. Subjects (15 males and 15 females) were qualified for this study based on an initial interview including the following criteria: age 21-23 (+/-1), no history of trauma, orthodontic treatment, or temporomandibular disorders (TMD). For each patient, the angle of the condylar path, incisal guidance angle (IGA), interincisal angle, as well as overbite and overjet were measured on cone beam computed tomography (CBCT). This was followed by the examination with the Modjaw® electronic axiograph recording and calculating the functional sagittal condylar guidance angle (SCGA) for the right and left TMJ during the protrusion. The results show that the mean functional axiographic measurement of SCGA in protrusion significantly correlates with the TMJ anatomy presented on CBCT. Moreover, a significant correlation was found between the values of SCGA in the functional and anatomical measurements in all its variants. It turned out that, statistically, the AB measurement was the most accurate. Finally, results showed that incisal relationships of permanent teeth such as overbite, overjet, incisal guidance angle and interincisal angle do not correlate with TMJ anatomy, and therefore, regarding an analyzed study group, do not affect the TMJ formation in young adults.

Comparison of accuracy of protrusive condylar guidance registration by two interocclusal recording materials in edentulous patients.

During complete denture fabrication making Interocclusal records plays an integral role to obtain the condylar guidance value. The study was conducted to compare the protrusive condylar guidance registration by two interocclusal recording materials-Quick setting plaster and Luxabite®(bisacrylic composite) in semi adjustable articulator for completely edentulous patients. Maxillary and Mandibular casts of the completely edentulous patients were mounted in Hanau®Wide Vue articulator. The Quick setting plaster and Luxabite®(bisacrylic composite) was used as interocclusal recording materials to program the protrusive condylar guidance angles in the articulators. The protrusive condylar guidance values registered in the articulator for the different interocclusal records were tabulated and statistically analyzed.. The mean protrusive condylar guidance values registered in the articulator was compared with two parameters obtained from the radiographic tracings -- the protrusive condylar path angle obtained with Quick setting plaster and Luxabite with the inclination of articular eminence to the Frankfort horizontal plane. From the study it was concluded that the Luxabite®(bisacrylic composite) material demonstrated better reproducibility of protrusive condylar guidance registration.than the Quick setting plaster.

Three-dimensional characteristics of temporomandibular joint morphology and condylar movement in patients with mandibular asymmetry

BackgroundInvestigating the morphological and functional effects on mandibular asymmetry (MA) is important not only to understand the developmental process of masticatory dysfunction, but also to provide suggestions for evidence-based occlusal treatment. AimTo evaluate three-dimensional temporomandibular joint (TMJ) morphology and its relationship to asymmetrical condylar movement in MA patients.Materials and methodsFifty subjects were divided into MA and control groups (n = 25 each) according to a menton deviation of 4 mm from the mid-sagittal plane. TMJ morphology (condyle, glenoid fossa and TMJ spaces) were evaluated using a three-dimensional analysis programme. Three-dimensional condylar movements (from the sagittal and horizontal planes) were recorded and measured by computerized axiography on protrusion. Side-to-side asymmetry was measured for each parameter. The asymmetry index value was calculated to assess the correlation between TMJ morphology and condylar movement. For the statistical analysis, Wilcoxon’s signed-ranked test, the Mann–Whitney U test, and Spearman’s rank correlation were used.ResultsGlenoid fossa volume, surface area, anteroposterior length, and condylar volume were significantly smaller, and articular eminence angle, glenoid fossa, and condylar axial angle were significantly larger, on the shifted side of the MA group when compared with those on the non-shifted side and the mean values of the control group (P < 0.05). The TMJ spaces of the MA group showed no bilateral difference but were significantly narrower in the medial, superior, and anterior joint spaces when compared with the control group (P < 0.05). Condylar path length and sagittal condylar inclination were significantly asymmetrical. The asymmetry index of the condyle volume was significantly correlated with that of the condylar path length (P = 0.005). The asymmetry index of the glenoid fossa volume and the articular eminence angle were significantly correlated with that of the sagittal condylar inclination (P = 0.009 and P = 0.002, respectively), and the asymmetry index of glenoid fossa volume was significantly correlated with the bilateral transverse condylar inclination (P = 0.006 and P = 0.016, respectively).ConclusionsMorphological asymmetry of the TMJ is significantly different between the shifted and non-shifted sides and is closely related to functional asymmetry of condylar movement in MA patients. (350/350).

Three-dimensional evaluation of condylar position in skeletal Class I and Class II malocclusions along with vertical facial morphology

Objectives: This study aimed to three-dimensionally evaluate and compare anatomic condylar position to glenoid fossa in skeletal Classes I and II malocclusions along with vertical facial morphology (VFM). Material and Methods: Full skull 50 cone-beam computed tomographies (CBCTs) were taken with teeth in maximum intercuspation of patients aged 18–45 years who were grouped as skeletal Classes I and II, 25 each based on ANB angle and the patient’s right condyle was analyzed on CareStream-3D viewing software. The VFM was categorized based on the Jarabak ratio. Statistical analysis was performed using Mann–Whitney and Chi-square test. Results: In skeletal Class II when compared to Class I, the condyle in the glenoid fossa was anteriorly positioned with reduced anterior (P = 0.006) and increased posterior (P = 0.04) distance showing eccentric position. The condyle was also positioned lower suggesting an increased distance in the upper joint space (P = 0.04). The reduced height of the articular eminence indicated the condylar path and its position. The angle of articular eminence (P = 0.44) was decreased. Statistically, significant difference was not found between the various vertical facial morphologies. Conclusion: CBCT provides precise diagnostic values of joint spaces in skeletal Classes I and II to differentiate ideal condylar position from non-ideal according to different skeletal patterns, VFM, and also to notice minor discrepancies in joint spaces quantitatively. Depending on increased or decreased distances in the joint spaces, one can identify any temporomandibular joint-related discrepancies.

Comparative Evaluation Of Clinical And Radiographic Horizontal Condylar Guidance Angle Values By Using Two Different Interocclusal Recording Materials In Dentulous Patients

Introduction: The success of prosthodontic procedures can be accurately determined by the exact replication of the patient’s condylar path using a semi-adjustable articulator. It allows the clinician to determine the morphology of the occlusal surfaces in relation to the condylar pathway during mandibular movements. If condylar guidance is not exactly registered, it might result in occlusal interferences during movements of the mandible and lengthen chairside adjustment time, which is inconvenient for the patient and dentist.Materials and methods: A total of 20 dentulous patients from 20 to 30 years of age group attending the department of prosthodontics at Sibar institute of dental sciences were selected for the study. Alu wax and jet bite were used to obtain the protrusive interocclusal record (PIR). Protrusive records were then used to program the semi-adjustable articulator to obtain HCGA values on both sides. Using the same protrusive records CBCT radiograph was taken. Radiographic images were traced on tracing paper and HCGA values were measured using Frankfort’s horizontal reference line (the line connecting porion and orbitale) and the mean curvature line (most-superior and most-inferior points of the curvatures) on both sides using a protractor. The data were analyzed by paired sample t-tests and Pearson’s correlation tests.Results: There was no significant difference between the right and left sides in the clinical and radiographic methods using Alu wax PIR. In the clinical method utilizing jet bite PIR, the right side had significantly higher HCGA values than on the left side. On CBCT, no such differences were found.Conclusion: CBCT horizontal condylar guidance angle values were higher than those obtained using the clinical method by using both records. Values obtained from both the methods, i.e., protrusive interocclusal record and cone-beam computed tomography, were compared and correlated.

Evolutionary Steps in the Development of a Patient-specific Temporomandibular Joint Prosthesis

Study Design Descriptive study (/review containing supporting case studies). Objective The temporomandibular joint has some distinctive features that were not taken into account during the initial development of temporomandibular joint prostheses, such as laterotrusive movements that are necessary for the proper grinding of food as well as synchronous and congruent movements made in conjunction with the healthy, contralateral joint. The aim of this article is to describe the development of a novel type of TMJ prosthesis that optimizes temporomandibular joint replacement. Methods The development was initiated by using contemporary technologies like computer-aided design customization, additive manufacturing, and surface treatments. Biocompatibility, proper fixation, and wear resistance, being prerequisites for the longevity of prostheses, were investigated next. Individual variables (condylar path, condylar axis angle, Bennet shift) were introduced as the main basis for physiological movements with the restoration of all functions. Early post-operative results ranging from 1 month to 4.5 years (11 patients, average follow-up period was 23.3 months) were assessed. Results The experience with 16 individualized total joint replacements in 11 patients is presented. The 3-year follow-up results of two-patient detailed studies are discussed, which show evidence of the promising restoration of all mandibular movements, when preoperatively present. Conclusions By incorporating various innovative and novel features (scaffold for re-attachment of lateral pterygoid, patient-specific functional parametrization, saddle-like design for retention, …) into a novel TMJ prosthesis concept, a major advance in function-reconstructive temporomandibular joint replacement was achieved. Early in vivo results (1 year after surgery) showed promising outcomes, involving both high increases in mandibular movements and decreases in pain scores.

Alterations in kinematics of temporomandibular joint associated with chronic neck pain.

Temporomandibular disorder (TMD) is an umbrella term for pain and dysfunction of the temporomandibular joint (TMJ) and its associated structures. Patients with TMD show changes in TMJ kinematics and masticatory muscle activation. TMD is commonly comorbid with non-specific chronic neck pain (NCNP), which may be one of the risk factors for TMD. This study aimed to investigate whether patients with NCNP have altered TMJ kinematics and masticatory muscle activity. This was a cross-sectional exploratory study including 19 healthy participants and 20 patients with NCNP but without TMD symptoms. TMJ kinematics was measured during mouth opening and closing, jaw protrusion and jaw lateral deviation. Surface electromyography was used to record the muscle activity of the anterior temporalis, masseter, sternocleidomastoid and upper trapezius while clenching. Furthermore, cervical posture, cervical range of motion (ROM) and pressure-pain threshold of the neck and masticatory muscles were measured. Compared with the healthy group, the NCNP group showed significantly reduced upper cervical rotation ROM (p=.041) and increased condylar path length (p=.02), condylar translation (opening p=.034, closing p=.011) and mechanical pain sensitivity of the upper trapezius (p=.018). Increased condylar translation was significantly correlated with reduced upper cervical mobility and poor cervical posture (r=-0.322 to -0.397; p=.012-.046). Increased condylar translation and path length in patients with NCNP may indicate poor control of TMJ articular movement, which may result from neck pain or may be a compensation for limited neck mobility. Evaluation of excessive TMJ translation may be considered in patients with NCNP.

Age-related variations in position and morphology of the temporomandibular joint in individuals with anterior openbite and crossbite: a multi-cross-sectional comparative study

BackgroundThis study aimed to compare the age-related positional and morphological characteristics of the temporomandibular joint (TMJ) between individuals with anterior openbite or crossbite and controls.MethodsThis multi-cross-sectional comparative study analysed cone-beam computed tomography images of 750 participants, equally divided into the openbite, crossbite, and control groups (OBG, CBG, and CG, respectively). Each group was further divided into five subgroups (8–11 years, 12–15 years, 16–19 years, 20–24 years, and 25–30 years). Measurements of the TMJ included the position of the condyles in their respective fossae and morphology of the condyles and fossae. Data were submitted to statistical analysis. The study adhered to the STROBE Statement checklist for reporting of cross-sectional studies.ResultsCondyles were positioned more posteriorly with increasing age in all groups, and the condylar position was more posterior in the OBG than in the CBG. The articular eminence inclination increased with age in all the groups. There were significant differences in the articular eminence inclination among the three major groups at the age of > 15 years, and the condylar path was flatter in the CBG than in the OBG.ConclusionsAge-related morphological and positional characteristics of the TMJ differed considerably among OBG, CBG and CG. Contrary to CBG, OBG was found to have relatively posterior condylar position and steeper condylar path.

Comparison Of Sagittal Condylar Angle Obtained Using Cone Beam Computed Tomography And Interocclusal Record Materials- An In Vivo Study

: The sagittal condylar guidance angle (SCCA) is calculated by the condyle and articular disc traversing the contour of the glenoid fossa and the articular eminence. The condylar path is controlled by the shape of the fossa, the attachments of the ligaments, the biting load during movement (muscular influence), and the amount of protrusion. The SCGA on an articulator is determined using protrusive records of the patient. Intraoral registrations may compromise accuracy because of dimensional instability of registration materials and it becomes difficult for the dentist to select an appropriate material. The use of cone beam computed tomography (CBCT) has recently become much more common, and when measuring the SCGA using CBCT, more reliable results can be expected. This study was designed to compare the SCGA obtained using CBCT and protrusive interocclusal record made using polyvinyl siloxane and aluwax. Thirty dentulous subjects were selected. SCGA was calculated using CBCT scans for each subject. Intraoral protrusive records were made using polyvinyl siloxane and aluwax bite registration materials at 6mm of protrusion. Records were used to program the articulator and variation in the SCCA was noted. No significant difference was observed between right and left mean values of SCGA in CBCT, polyvinyl siloxane and aluwax. Positive correlation was found between all the three groups; however, significant difference was found in the mean values of SCGA between CBCT and polyvinyl siloxane, CBCT and aluwax (P=0.0001). No significant difference was found in the mean values of SCGA between polyvinyl siloxane and aluwax (P=0.9254). CBCT gave higher mean SCGA values than those obtained using polyvinyl siloxane and aluwax on semi-adjustable articulator in dentulous subjects; whereas mean SCGA values were comparable between polyvinyl siloxane and aluwax. The right and left SCGA values were comparable in each method.

Correlation between the position of the glenoid fossa and condylar translational movement in skeletal Class III mandibular asymmetry patients.

SummaryObjectivesUnderstanding the mechanism of mandibular asymmetry (MA) is important to provide suggestions for occlusal treatment and to know the developmental process of masticatory dysfunction. To investigate the morphological and functional effects on MA, we evaluated the three-dimensional position of the glenoid fossa and its relationship to asymmetrical condylar translational movement.MethodsIn this retrospective study, 50 subjects who previously underwent computed tomography for surgical purposes were divided into MA and control groups according to a menton deviation of at least 4 mm from the mid-sagittal plane. The glenoid fossae positions were evaluated using a three-dimensional analysis program. Condylar translational movements were recorded and measured by computerized axiography on protrusion. Side-to-side asymmetry was measured for each parameter. Asymmetry index value was calculated to assess the correlation between glenoid fossa position and condylar movement. Wilcoxon’s signed-ranked test, Mann–Whitney U-test, and Spearman’s rank correlation were used for the statistical analysis.ResultsIn the MA group, glenoid fossa position on the shifted side was significantly inferior and posterior as compared to that on the non-shifted side and of the control group. Condylar path length and sagittal condylar inclination were significantly greater on the shifted side versus non-shifted side, while no significant difference was found in transverse condylar inclination. The asymmetry index of the anterior–posterior glenoid fossa position was significantly correlated with that of condylar path length and bilateral transverse condylar inclination. In the control group, there were no significant correlations among the morphological and functional parameters.LimitationsThis study did not consider muscle activity and disc position, which may affect condylar movement.ConclusionsFunctional asymmetry of condylar translational movements is closely related to asymmetry of glenoid fossa position in MA patients.

Asymmetry of dental or joint anatomy or impaired chewing function contribute to chronic temporomandibular joint disorders

IntroductionThe etiologies of most chronic temporomandibular joint disorders are unknown. However, an association between habitual chewing on a particular side and chronic temporomandibular joint disorders has been reported.The aim of this study was to investigate the differences between sides (affected vs unaffected) of biodynamic factors (including lateral dental guidance determined by dental anatomy) or condylar path angles (determined by temporomandibular joint morphology) and chewing function (physiological alternate chewing vs single habitual chewing side). The study scope was to investigate possible etiological factors to improve the understanding of temporomandibular joint disorders.The null hypothesis was that no difference would be found between sides that are or are not affected by chronic temporomandibular joint disorders in chewing function or in levels of dental or temporomandibular joint remodeling. MethodsThis cross-sectional, double-blind study involved 24 adults with substantial, chronic, unilateral symptoms diagnosed as temporomandibular joint disorders. Chewing function, temporomandibular joint remodeling (using axiography) and dental anatomy (lateral guidance angles using kinesiography) were assessed. ResultsHabitual chewing on one particular side was observed in 17 of 24 participants; significantly more (n=15) chewed on the affected side than on the unaffected side (P=0.002 in a two-tailed Fisher’s exact test; risk estimate=4.5; 95% CI 1.326–15.277). The condylar path (CP) angle was steeper on the affected side than on the unaffected side (mean (standard deviation)=50.52° (9.98°) versus 45.50° (7.98°); P=0.002 in a two-tailed t-test). The lateral guidance (LG) angles were flatter on the affected side in all 24 participants. ConclusionOur results suggest that habitual chewing on one side may be associated with increasing condylar path, with flattening lateral guidance angles, and also with chronic temporomandibular joint disorder on the habitual chewing side.

Biomechanical impact of the porous-fibrous tissue behaviour in the temporomandibular joint movements. An in silico approach

The movement of the temporomandibular joint (TMJ) is a function of its complex geometry and its interaction with the surrounding soft tissues. Owing to an increase in the prevalence of temporomandibular joint disorders (TMDs), many computational studies have attempted to characterize its biomechanical behaviour in the last 2 decades. However, most such studies are based on a single computational model that markedly simplifies the complex geometry and mechanical properties of the TMJ's soft tissues. The present study aims to computationally evaluate in a wider sample the importance of considering their complex anatomy and behaviour for simulating both damping and motion responses of this joint. Hence, 6 finite element models of healthy volunteers' TMJ were developed and subjected to both conditions in two different behavioural scenarios. In one, the soft tissues' behaviour was modelled by considering the porous-fibrous properties, whereas in the other case they were simplified assuming isotropic-hyperelastic response, as had been traditionally considered. The damping analysis, which mimic the conditions of an experimental test of the literature, consisted of applying two different compressive loads to the jaw. The motion analysis evaluated the condylar path during the mandible centric depression by the action of muscular forces. From the results of both analyses, the contact pressures, intra-articular fluid pressure, path features, and stress/strain values were compared using the porous-fibrous and isotropic-hyperelastic models. Besides the great differences observed between patients due patient-specific morphology, the porous-fibrous approach yielded results closer to the reference experimental values and to the outcomes of other computational studies of the literature. Our findings underscore, therefore, the importance of considering realistic joint geometries and porous-fibrous contribution in the computational modelling of the TMJ, but also in the design of further joint replacements or in the development of new biomaterials for this joint.

Automated Real-Time Evaluation of Condylar Movement in Relation to Three-Dimensional Craniofacial and Temporomandibular Morphometry in Patients with Facial Asymmetry.

The aim of this study was to investigate the correlation between craniofacial morphology, temporomandibular joint (TMJ) characteristics, and condylar functional movement in patients with facial asymmetry using an up-to-date automated real-time jaw-tracking system. A total of 30 patients with mandibular asymmetry and prognathism were included. Three-dimensional (3D) craniofacial and TMJ morphometric variables were analyzed in images captured using cone-beam computed tomography. Three-dimensional condylar movements were recorded during the opening, protrusion, and laterotrusion of the jaw and divided into those for deviated and non-deviated sides. Overall functional and morphometric variables were compared between the sides by a paired t-test. Pearson’s correlation analysis and factor analysis were also performed. As a result, significant differences were found between the sides in morphometric and functional variables. The condylar path length was significantly longer and steeper on the deviated side during protrusion and lateral excursion. TMJ morphometric asymmetry, more so than the craniofacial morphologic asymmetry, seemed to be reflected in the functional asymmetry, representing different correlations between the sides, as supported by factor analysis. This study provides evidence explaining why the asymmetric condylar path remained unchanged even after orthognathic surgery for the correction of craniofacial asymmetry.

Reproducibility of Sagittal Condylar Path Inclination Assessed by Protrusive Interocclusal Record with Two Different Techniques of Facebow Registration

Purpose: The purpose is to validate whether the data obtained for sagittal condylar inclination are correctly reproduced on the semi-adjustable articulator using protrusive interocclusal records for conventional facebow registration method (orbitale (OR) as an anterior point of reference) and facebow registration using bubble leveler (BL) as an anterior point of reference and compared these values with the values obtained by lateral cephalogram (gold standard). Materials and Methods: In total, 30 individuals (20 males and 10 females) with proper teeth alignment, facebow registrations were recorded using OR as an anterior point of reference (Group A, conventional technique) and WBL as an anterior point of reference (Group B). The sagittal condylar path inclination was measured and compared using protrusive interocclusal records for both the groups. These values compared with the values for sagittal condylar path inclination obtained using lateral cephalogram (Group C) using one-way analysis of variance (P &lt; 0.05). Results: There was no statistically significant differences observed in the values of sagittal condylar inclination for all three groups with P = 0.583. Conclusion: This study suggests that BL technique can be used for the orientation of maxillary cast on the semi-adjustable articulator as accurately as the conventional approach, for those practitioners who find difficulty in locating the OR for those patients with deformity in facial region. Lateral cephalogram provides almost the same measurements of sagittal condylar path inclination as obtained using protrusive interocclusal record on facebow registrations using OR and BL as an anterior point of references.

Computer Program for Digital Data Analysis of Facebow Records – Part ІI

Abstract The aim of the study was to perform a comparative data analysis of the values of sagittal condylar path and arrow point angle, obtained through measurements based on facebow records, by applying two methods: manual and digital by using the Mini-Maxi Facebow Analyzer computer program. Material and method: The program was tested through processing the data of 101 subjects (52 men and 49 women). The left and right sagittal condylar path was registered by using the Mini-Maxi facebow and the mandibular central position was determined by intraoral graphic registration. The data of each subject were entered into the program and the individual values of the registered parameters were calculated. Then, a comparative statistical analysis of the data obtained by the conventional manual measurement with a protractor and the computer program was performed. Results: The mean value of the sagittal condylar path obtained through the computer program was 34.89˚ for the right side and 35.86˚ for the left side. The mean value of the arrow point angle obtained through the computer program was 107.52˚. The differences between the data for men and women were not statistically significant (р &lt; 0.05). Conclusions: The computer program provides an accurate analysis of facebow records and assists in determining individual patient’s movement parameters of the lower jaw. The comparative analysis of the accuracy of parameters obtained through conventional and digital measurements demonstrates the high product reliability of the computer program.

A Study to Relate Sagittal Condylar Path and Horizontal Incisal Path with Bilateral Balanced Occlusion in Edentulous Subjects

Abstract Introduction Bilateral balanced occlusion is achieved when there is equilibrium on both sides of the prosthesis, due to the simultaneous contact of the artificial teeth in centric and eccentric occlusion. One of the areas in which research is lacking is the relation between sagittal condylar path (CP) and horizontal incisal path (IP) with optimal balanced occlusion. Materials and Methods Semiadjustable Articulator Artex Arcon AP with Rotofix facebow, 40 µ Bosch articulating paper of red and blue color, protractor, centric and protrusive interocclusal plaster records were used for the study on 50 completely edentulous subjects. Teeth arrangement was done with optimal balanced occlusion, and the numbers of contacts were recorded in centric relation and eccentric positions. Statistical analysis was done by using student’s t test and Karl Pearson coefficient correlation. Results The average sagittal CP was 30.38° in the age group of 40 to 55 years and 32.58° in the age group of 56 to 70 years, and the average horizontal IP was 15.79° in the age group of 40 to 55 years and 16.04° in the age group of 56 to 70 years.Statistically significant results were found between sagittal CP, horizontal IP with bilateral balanced occlusion in the age group of 40–55 years. Conclusion Statistically significant relations were found in balanced occlusion between waxed up denture on articulator, processed denture on articulator and processed denture on articulator after selective grinding. Balanced occlusion is more predictable in a younger group of individuals.

Cone-beam Computed Tomographic Evaluation of the Anatomical Changes of Temporomandibular Joint Use of Pre-post Dentures: A Time-control Study

The growth of the temporomandibular joint (TMJ) gets affected by multiple factors like aging, occlusion state, and by the movement of the jaw while masticating and swallowing. Radiographic imaging is often utilized as a vital diagnostic adjunct in the evaluation of certain examinations of the TMJ. In this in vivo study, 30 male participants with mean age 55 years, having edentulous maxillary and mandibular arches from the Outpatient Department of Prosthodontics, were randomly selected. Group I (n = 30) patients who were edentulous for the last 4-5 years but without wearing dentures. Whereas group II (n = 30) patients who were edentulous for the last 4-5 years but were wearing dentures for this period. Maxillary and mandibular dentures were fabricated and delivered to subjects. Subjects were subjected to the TMJ analysis with the help of CBCT. Radiological images of dentomaxillofacial structures were analyzed by a specialist with a dual monitor inside a darkened silent room. On the monitor, three times measurements were recorded followed by calculation of mean value. The recordings were taken on both sides and thus, 210 sites were analyzed altogether, followed by the statistical analysis using SPSS software version 15.0. The mean ages of group I and II were 59.00 ± 6.74 and 58.27 ± 6.75 years, respectively. The intra- and intergroup comparisons were done using a one-sample t-test. Differences in mean intercondylar width in groups I and II were not found to be statistically significant. The difference in mean length of glenoid fossa was not statistically significant at any of the above observation periods. A continuous decline in mean length of glenoid fossa was observed with time in both groups. The range of change in articular eminence length was found to be statistically significant for both the groups (p < 0.05). This study shows that the articular eminence flattening is correlated with age; on the other hand, the rate of deformation was found significantly more in total edentulous subjects as compared to subjects having normally maintained occlusion. The anatomical changes inside the TMJ have been much greater expressed within the completely edentulous subjects in whom the angle of sagittal condyle path declines and so does the articular eminence height. It is essential to provide the edentulous patient with early prosthetic and occlusal rehabilitation after extractions to prevent the anatomical changes in TMJ.

Computerized ultrasonic axiographic evaluation of condylar movement in patients with internal derangement of the temporomandibular joint.

To evaluate condylar movement during lateral excursion in individuals with internal derangement of the temporomandibular joint (TMJ) using ultrasonic axiography. A total of 34 patients with internal derangement of the TMJ and 34 participants in the control group were examined. Mandibular functional movement was recorded by ultrasonic axiography. Three-dimensional condylar movement was measured in the working and balancing condyles. Significant differences in condylar movement were found between the two groups. In the group with internal derangement of the TMJ, the three-dimensional linear distances of the condylar path in a working condyle were greater than in the control group during lateral excursion. The speed of the balancing condyle in the returning path of lateral excursion was significantly greater in the group with internal derangement than in the control group. The results of the present study indicate that internal derangement of TMJ may affect the working and balancing condylar movements during lateral excursion.