Functional Mandibular Movement Research Articles

Investigation of the precision of a novel jaw tracking system in recording mandibular movements: A preliminary clinical study

ObjectivesThis preliminary study aimed to clinically assess the precision of a novel optical jaw tracking system (JTS) in registering mandibular movements (MMs) of protrusion and mediotrusion. MethodsTwenty healthy participants underwent recordings using Cyclops JTS (Itaka Way Med) for functional MMs of protrusion and laterotrusion by two trained clinicians. Each subject performed five registrations at different times according to a standardized pattern within one-month period. The angulations of protrusive and mediotrusive functional paths within the first 2 mm from the maximal intercuspal position (MIP) were calculated for each trace, using a data software for angle measurements. Descriptive statistics were used to assess the repeatability of the recordings for each participant and MM. Additionally, inferential statistics were carried out on standard deviation values obtained (α=0.05). ResultsThe overall precision for all the patients was 7.07±3.37° for the protrusion angle, 5.24±2.24° for right laterotrusion and 5.14±3.06° for left laterotrusion angles. The protrusion angle ranged from 3.08° to 13.57°, while the right and left laterotrusion ranged from 1.82° to 9.42° and from 1.58° to 10.59°, respectively. No statistically significant differences were observed between different functional MM types and gender (p > 0.05). ConclusionsRecordings functional MMs of mediotrusion and protrusion using Cyclops JTS showed consistent repeatability, regardless of gender and functional MM type. The results revealed non-negligible variations that may be due to the patients’ abilities to precisely reproduce jaw movements or to the operator's ability to consistently connect the kinesiograph. Clinical significanceCapturing functional MMs digitally and importing the data into dental CAD software is essential for virtual waxing in prosthetic rehabilitations to design a functionalized adapted occlusion. Establishing the repeatability of MM recordings by a JTS is a crucial step in better understanding this novel JTS in the market. This process could facilitate the interpretation of cusp angles, aid in CAD dynamic technical modeling, and enhance clinical data communication between clinicians and technicians in a modern workflow.

Electromyographic activities of the jaw and facial muscles in subjects with different vertical skeletal patterns and breathing modes.

Mouth breathing (MB) can affect morphological changes in the craniofacial structures, electromyography is widely used for quantitative analysis of muscle function. The aim was to evaluate the electromyographic (EMG) activities of the anterior temporalis (TA), masseter muscle (MM), orbicularis oris superior (OOS) and mentalis muscle (MT) in children with different vertical skeletal patterns and breathing modes during rest and various functional mandibular movements. BioEMG III was used to measure the variations in EMG activities of TA, MM, OOS, and MT in 185 subjects aged 6-12 years during continuous clenching, rest, maximal intercuspation, lips closed lightly and swallowing. The results of logistic regression analysis showed that the model with vertical skeletal patterns as the dependent variable was ineffective (p=.106), while the model with breathing modes as the dependent variable was effective (p=.000). When considering both vertical skeletal patterns and breathing modes, the following significant differences were found. (1) In the normal-angle group, the EMG ratio in OOS with lips closed lightly of MB was significantly higher than NB (p=.005). (2) In the low-angle group, EMG ratios in TA and MM during the swallowing of MB were significantly lower than NB (p=.020, p=.040, respectively). (3) In the high-angle group, EMG ratios of MB were significantly higher in MT during continuous clenching, rest, lips closed lightly and swallowing (p=.038, p=.036, p=.005, p=.028, respectively), and OOS with lips closed lightly compared to NB (p=.005). Breathing modes and vertical skeletal patterns interacted to alter maxillofacial EMG activities, with breathing modes having a greater effect.

An Evaluation of Jaw Tracking Movements in Patients with Total Joint Replacements versus a Control Group.

Background and Objectives: One form of treatment for degenerative temporomandibular joint diseases such as osteoarthritis, rheumatic arthritis, TMJ ankylosis, and condylar resorption is total joint replacement. The aim of this study was to examine the function of the temporomandibular joint after prosthetic joint replacement. Materials and methods: Fifteen patients with unilateral or bilateral TMJ total joint replacements and 15 healthy controls were evaluated via a SICAT JMT+ device. This non-invasive system measures 3D position and linear movements in all degrees of freedom and allows undisturbed functional mandibular movements to provide a quantitative evaluation. In addition, a TMJ questionnaire consisting of the subjective symptoms was also obtained. To date, no similar studies have been cited in the literature. Results: Mandibular movements after prosthetic joint replacement were recorded during opening, closing, protrusion, and lateral excursive movements and were all significantly decreased compared to those of controls. In the treatment group, the maximum incisal opening was 33.46 ± 5.47 mm, left lateral movement was 1.91 ± 2.7 mm, right lateral movement was 1.74 ± 1.74 mm, and protrusive movement was 2.83 ± 2.05 mm. The p-value comparison study and control group indicated significant difference (p < 0.0001) between the two groups. The study group stated a high level of satisfaction with the total joint replacement. Conclusion: Within the limitations of the study, the following conclusions can be drawn: (1) TMJ replacement patients showed significantly limited jaw movements compared to the control group; (2) a small percentage of TMJ replacement patients still present low levels of pain but improved chewing ability and quality of life.

Reliability of a Trapezium Miniplate with Endoscope-Assisted Internal Fixation in Mandibular Subcondylar Fractures: A Three-Dimensional Analysis.

This study aimed to evaluate the reliability of a trapezium plate for open reduction and internal fixation (ORIF) of mandibular subcondylar fractures with the simultaneous use of an endoscope. We selected and retrospectively studied 18 patients (12 males and 6 females) with unilateral mandibular subcondylar fractures who visited the Wonju Severance Christian Hospital. The mean age of the patients was 43.43 ± 15.76 years. Patients underwent ORIF with trapezium miniplate application through an intraoral incision under general anesthesia. The clinical and radiographic findings of the fractured side were compared with those of the non-operated side at 6 months follow-up. All occlusions became stable, and transient functional disturbances disappeared within 6 months of periodic follow-up. Functional mandibular movement recovered within the normal range, with an average mouth opening of 41.5 mm, protrusion of 7.5 mm, and lateral excursion of 7 mm at 6 months. Radiographic controls and statistical analysis confirmed a decent anatomical reduction in all 18 cases. In conclusion, the use of a trapezium miniplate with endoscope-assisted ORIF in mandibular subcondylar fractures can be useful for fixation and functional recovery.

Modjaw® device: Analysis of mandibular kinematics recorded for a group of asymptomatic subjects

ABSTRACT Objective To assess the repeatability and kinematic data of Modjaw® recordings from a group of asymptomatic patients. Methods Modjaw® mandibular kinematic data were recorded for 22 asymptomatic volunteers (DC/TMD questionnaire). Sagittal (SCI at 3 and 5 mm) and transversal (TCI at 4 mm) condylar inclination values of the instantaneous center of rotation were measured over two recording sessions. The repeatability of recordings was determined from the intraclass correlation coefficient (ICC), which is based on a one-way random-effects ANOVA. Results The repeatability of recordings was found to be good to excellent. The mean TCI in mediotrusion was 7.1° ± 5.1, and the mean SCI in protrusion was 51.07° ± 9.43. Conclusion The Modjaw® device reliably records the patient’s real hinge axis kinematics during functional mandibular movements. Data can be transferred with the patient’s personal reference plane and digital casts to the CAD/CAM software.

The Influence of Altering the Morphology of the First Mandibular Molar on Functional Mandibular Movements: A Pilot Study

Purpose: Altering the tooth morphology is a frequent clinical situation and it requires replacing the lost tooth substance by direct/indirect treatment methods. The purpose of this study is to identify the optimal study group size to quantify the extent to which the change in dental morphology influences the amplitude and path of the mandibular movements at the condylar and dental level. Materials and Methods: The study was performed on 10 young participants, without associated joint pathology, with healthy complete dentition. The Zebris JMA System (Zebris Medical GmbH, Germany) condylograph were used. The condylar and occlusal parameters were registered, before and after the composite occlusal modification on the right first mandibular molar was made and data were synthesized as Excel Data. The SPSS2 software was used for statistical analyses, a descriptive analysis of the pair differences was performed, Kolmogorov-Smirnova and Shapiro-Wilk tests were applied to verify the normality, paired sample test for 0,05 level of significance and 80% power was applied to determine the proper sample size. Conclusion: The results show a change in movement parameters at both condylar and dental level: the sagittal motion of the condyle on both sides tends to have a more vertical trajectory, the incisal guidance in protrusion and the guidance in the lateral movement on the modified part are steeper, lateral movement guidance on the other side is shallower, a tendency of retrusion is noted in both condyles. Respecting original dental morphology is essential for functional harmonious integration of the restoration.

Anatomical and Clinical Implications in Neocondyle Stability After a Condylectomy.

A modified high condylectomy with arthroplasty and FST results had been studied in anatomical, radiological, and clinical model. Early findings after FST are promising. A slight improvement in lateral jaw movement was noted after condylectomy with arthroplasty (P < 0.05) both in early and late follow-up. Incisal opening, mandibular protrusion, and lateral movement were sustained. A stable condyle position within the fossa was achieved in each case of condylectomy with arthroplasty (P < 0.05). The FST condylectomy and reattachment of the lateral pterygoid muscle in a new, wider position provided an improvement in lateral jaw movement as well as in incisal opening and mandibular protrusion in early follow-up examination compared to the presurgical values. It seems that the FST enabled a better new condylar head position in the glenoid fossa and improved early functional mandibular movement.

Accuracy of a Real-Time, Computerized, Binocular, Three-Dimensional Trajectory-Tracking Device for Recording Functional Mandibular Movements.

ObjectiveDevelopments in digital technology have permitted researchers to study mandibular movements. Here, the accuracy of a real-time, computerized, binocular, three-dimensional (3D) trajectory-tracking device for recording functional mandibular movements was evaluated.MethodsAn occlusal splint without the occlusal region was created based on a plaster cast of the lower dentition. The splint was rigidly connected with a target on its labial side and seated on the cast. The cast was then rigidly attached to the stage of a high-precision triaxial electronic translator, which was used to move the target-cast-stage complex. Half-circular movements (5.00-mm radius) in three planes (XOY, XOZ, YOZ) and linear movements along the x-axis were performed at 5.00 mm/s. All trajectory points were recorded with the binocular 3D trajectory-tracking device and fitted to arcs or lines, respectively, with the Imageware software. To analyze the accuracy of the trajectory-tracking device, the mean distances between the trajectory points and the fitted arcs or lines were measured, and the mean differences between the lengths of the fitted arcs’ radii and a set value (5.00 mm) were then calculated. A one-way analysis of variance was used to evaluate the spatial consistency of the recording accuracy in three different planes.ResultsThe mean distances between the trajectory points and fitted arcs or lines were 0.076 ± 0.033 mm or 0.089 ± 0.014 mm. The mean difference between the lengths of the fitted arcs’ radii and the set value (5.00 mm) was 0.025 ± 0.071 mm. A one-way ANOVA showed that the recording errors in three different planes were not statistically significant.ConclusionThese results suggest that the device can record certain movements at 5.00 mm/s, which is similar to the speed of functional mandibular movements. In addition, the recordings had an error of <0.1 mm and good spatial consistency. Thus, the device meets some of the requirements necessary for recording human mandibular movements.

INDIRECT IMPACT OF AN ACRYLIC LABIOLINGUAL SPLINTS MANGING FRACTURED PEDIATRIC MANDIBULAR DENTAL BEARING AREAS ON TEMPOROMANDIBULAR JOINT FUNCTIONS

Objective: The purpose of the current study was to investigate the indirect impact of an acrylic labio-lingual splints as a fixation maneuver of pediatric mandibular body fractures on temporo- mandibular joint (TMJ) function. study design: The current study was conducted on twenty patients of both genders (12 boys and 8 girls) with age ranging from 5-10 years old. These patients suffered from 20 single mandibular fractures at teeth bearing area. The patients were divided into two groups; pre-school age group (G1) and school age group (G2). They were conservatively treated through closed reduction and indirect fixation by using acrylic labio-lingual splint tightened by 2-4circummandibular wires under local anesthesia and conscious sedation. The patients were followed up clinically and radio-graphically immediately, and at (one, three, six, nine and twelve) months postoperatively. Results: Through all follow up period; all mandibular functional movements well not affected. Statistically; there were non-statistically significance decrease in all functional mandibular movement in both groups. In the meantime there non-statistically significance decrease in all functional mandibular movement in the same group from immediate post-operative period to the end of the postoperative follow up period Conclusion: An acrylic labio-lingual splints as the legendary mean of indirect fixating of pediatric mandibular body fractures had no deleterious effect on TMJ functional activities.

Significance of Facebow for Dental Restorations

An accurate determination, recording and transfer of jaw relation records from patients to the articulator is essential for the dental restoration function, facial appearance and maintenance of patient’s oral health. As unsatisfactory maxilla-mandibular relationship will eventually lead to failure of complete dentures and necessitate time consuming and costly repairs. Facebow plays an integral part of this maxilla-mandibular relationship transfer from the patient mouth to that of the articulator. Thus, this article attempts to discuss the facebow and its significance in dental restoration treatment. Maxilla is a part of the cranium and is a fixed entity. When the teeth of both jaws come in contact, maxilla becomes related to the mandible so that entire craniomaxillary complex is articulated with a moving bone, which is the mandible. The opening movement to bring the jaw from occlusal to rest position is almost a pure hinge movement. Here the mandible moves on an arc of a circle with a definite radius from the temporomandibular joint. This path of the condyle is determined by the curvature of the condylar head and the curvature of glenoid fossa. Since the radius is not constant for all the patients, it has to be determined for every individual patient, i.e., the relation of maxilla to the opening and closing axis has to be determined. The upper jaw in the human skull is positioned uniquely to the lower jaw. This position is different for every person., Also , the anatomy of maxilla and the temporomandibular joint varies from persons to persons. Thus, recording of the orientation jaw relationship is very important which is done with the help of facebow record. Certain terminologies (according To GPT-8) are important to know the importance of facebow. Hinge axis defined as an imaginary line passing through the two mandibular condyles around which the mandible rotates without translatory movement. Gnathological society defines it as imaginary line connecting the center of one condyle to the center of rotation of the other Like centric relation ,hinge axis is Stable ,Learnable, Recordable, Reproducible and Repeatable. Terminal hinge axis defined as when the condyles are in their most superior position in the articular fossa and the mouth is purely rotated open, the axis around which movement occurs is called as Terminal hinge axis.Clinical Use Of Terminal Hinge Axis is firstly is the location of the transverse hinge axis serves only to orientate the maxilla and to record the static starting point for functional mandibular movements. It does not record centric relation or condylar movements. Secondly it ,allows the transfer of the opening axis of jaws to the articulator so that occlusion would be on the same arc of closure as in the patients mouth. Therefore it is used as an important reference in mounting casts in the articulator, so that the opening axis of the articulator coincides with the terminal hinge axis of the patient. And this axis can be located when the mandible is in its most posterior unstrained position by means of a Face bow. I. Face Bow The face bow is a caliper like device that is used to record the relationship of the jaws to the temporomandibular joints or the opening axis of the jaws and to orient the casts in the same relationship to the opening axis of the articulator.The term, “face bow,” probably evolved from a statement by A.D. Grit man, who described the “implement devised by Prof. Snow. as a bow of metal (that) reaches around the face. Face bow record is used in balanced occlusion in complete denture, in edentulous Class I & II cases, Open anterior bite or end to end relationship, Single restoration on II molar not for premolar and I molar, Segmental restoration, Anterior restoration and restoration of entire quadrant Significance of Facebow for Dental Restorations www.iosrjournals.org 2 | Page II. Parts Of Face Bow It is constructed in 3 bars, 1 anterior, 2 lateral. TABLE-1 PARTS OF FACEBOW

機能運動時の咬合接触

本方法は, 歯列の3次元形態データと6自由度顎運動データを用いてグラフィックターミナル上で顎運動を再現し, 任意の顎位における上下顎の咬合小面間距離を算出, 画面上に表示することにより, 機能運動中の咬合接触あるいは離開の状態を評価するものである.このような方法の最大の利点は, 臨床的には観察することが困難な機能運動中の咬合状態を評価することが可能であるという点にある.本システムが咬合の可視化装置として臨床で活用されるようになれば, クラウンの咬合調整から咬合の再構成にいたるまで, 顎運動に調和した咬合を与えるための最も有効な診断, 治療支援となることが期待できる.

そしゃく運動経路と側方限界滑走運動経路の一致性について

Mandibular movement occurs during chewing, speech and swallowing functionally or during bruxism and clenching parafunctionally. Further, the occlusal facet is caused by functional mandibular movement and parafunctional mandibular movement. However, it is not defined to what extent the occlusal facet is within the range of functional mandibular movement. The purpose of this study was to examine the extent of functional tooth grinding in chewing mandibular movement. One hundred dental students were used in this study, and the portion of correspondence of path of chewing and lateral border movement was measured using Sirognathograph Analyzing System III. As a result, some subjects had a large corresponding portion of path of chewing mandibular movement and path of lateral border movement. The extent of functional tooth grinding in chewing movement has been considered to be small near the centric occlusion, however, the results suggested that a large portion of the grinding surface was used by functional mandibular movement.

機能運動時のこう合接触およびクリアランス

We previously reported the three-dimensional analyzing system of occlusal tooth contacts. Using this system, we studied the functional tooth contacts and clearance of five subjects particularly during masticatory movements.1. Tooth contacts and interocclusal clearance less than 1 mm can be analyzed during functional mandibular movements by using the six-degree-freedom jaw movement data and the three-dimensional morphology measurement of tooth surfaces.2. Dominant tooth contacts were observed on the non-chewing side than on the chewing side during masticatory movements. The tooth contact sites on the non-chewing side corresponded to the region of contacts or tiny clearance which occurs during mediotrusive movement.3. Tooth contacts and clearance at the beginning and the end of chewing cycle (jaw opening and jaw closing) were compared with those during lateral- excursive movement. Tooth contacts and clearance during masticatory movement toward opening more corresponded to those during lateral excursive movement.In summary, the non-chewing side tooth contacts may play an important role in the support and guidance of mandible throughout the functional masticatory movements. That means there is a need for more precise evaluation regarding non-working side occlusal tooth contacts in functional movements.

The range of functional mandibular movement in bruxists. 4. Discussion and conclusions

A study of some kinesiological characteristics of the mandible of non-bruxist and bruxist subjects was carried out using a closed circuit television point movement tracking system. The use of incandescent light bulbs attached to the incisor teeth of the maxilla and mandible as the point movement source allowed records to be made without head restraint of the subjects examined. Records were stored on magnetic tape. Mandibular movement was studied using the vertical, lateral and anteroposterior components of movement. Two components of movement were combined electronically for all three combinations of the components and the signals produced were used to prepare envelopes of motion graphically, on an X-Y recorder, in the coronal, sagittal and horizontal planes. Qualitative analysis of envelopes of motion in three planes mutually at right angles proved useful in providing information which demonstrated trends to minor differences between non-bruxist and bruxist subjects. However, variations of patterns of movement occurred frequently enough in each test of each group to negate any possibility at present of using these techniques in the development of diagnostic procedures.

The range of functional mandibular movement in bruxists. 3. Results

Part 3 presents the results of the examination carried out in Part 2. A summary of the tooth tapping task and the chewing task is given with comment on the coronal, sagittal, and horizontal plane of bruxists and non-bruxists.

The range of functional mandibular movement in bruxists. 2. Materials and method

Part 2 of this investigation of the range of functional mandibular movement of bruxists consists of the examination (via history, questionnaire and clinical observation) and recording of the mandibular movement of a variety of subjects, non-bruxist and bruxist.

The range of functional mandibular movement in bruxists. 1. Introduction and review of the literature

The aim of this study is to examine and compare functional mandibular movements of nonbruxist and bruxist subjects. Part 1 presents introductory remarks and a review of the literature including a discussion of the many study techniques ranging from direct photography to magnetometry and closed circuit television.

Using the Kinesiograph to measure mandibular movements during speech: A pilot study

This study was a pilot investigation to determine a method of measuring mandibular movement during speech using the Kinesiograph. Some observations and trends were evident. 1. 1. The Kinesiograph is an excellent instrument for measuring mandibular movement in three dimensions. 2. 2. Production of the /s/ sound can occur anywhere within a three-dimensional range rather than at one position. 3. 3. The distance between the upper and lower incisors during speech was much less than 1 mm and was consistent throughout the range used by each subject. 4. 4. The functional angle of mandibuiar movement during speech to the maxillary occlusal plane was essentially the same as the angle of rest position to centric occlusion and appeared to be related to the cephalometric occlusal plane angle. It seems likely that rest position is the key to functional mandibular movement. 5. 5. Three-dimensional clinical studies of mandibular movement during speech using the Kinesiograph could lead to more precise answers to questions concerning mandibular function and occlusal dysfunction.

Pantographic tracings of mandibular movements and occlusion

Inconsistencies exist in the literature concerning the relationship of functional mandibular movements and border tracings recorded by pantographs. This study was undertaken to determine the relationship of functional movement and border tracings. A pantograph was assembled to clutches attached to anterior teeth. Chewing studies were performed on four subjects using different test foods. The functional movements of two subjects contacted the border tracing frequently from centric relation while the functional movements of two subjects were restricted to the tracings made from centric occlusion and influenced by occlusal interferences. The occlusion of one of the subjects with restricted functional movements was adjusted, and subsequently, the functional movements frequently contacted the border tracings. This study suggests that occlusion in harmony with border tracings may be the most physiologic.

Investigation of Functional Mandibular Movements

The Case Gnathic Replicator has been developed to measure and record jaw motion and position during human preconscious (functional) chewing. This system is providing a facility for the study and teaching of the basics of oral physiology and the development of an applied clinical technology.