Jaw Movement Data Research Articles

Digital jaw relation recording to evaluate a new vertical dimension of occlusion using CAD/CAM-fabricated tooth-colored splints: a case report.

Pronounced defects of the dental hard tissue can be caused by different etiologic factors. Most frequently, they are associated with changes in the vertical dimension of occlusion (VDO), which may also influence the condylar positions. These defects can lead to irreversible loss of tooth structure and have dramatic functional and esthetic consequences, often requiring complex rehabilitation. In this situation, CAD/CAM-fabricated occlusal splints made of tooth-colored polycarbonate are a proven and safe pretreatment approach in terms of esthetics and function. Rebuilding lost dental hard tissue to restore the occlusion and VDO to an adequate condylar position is a prerequisite for any sustainable and functional rehabilitation. In the future, digital systems will support this complex process, customizing it and making it simpler and more precise. The DMD-System (Ignident) provides patient-specific jaw movement data to optimize the CAD/CAM workflow. This system allows real movement patterns to be digitized and analyzed for functional and potential therapeutic purposes, integrating them into the dental and laboratory workflow. In the present case, the familiar tooth-colored CAD/CAM-fabricated occlusal splint is supplemented by digital centric jaw relation recording and individual movement data.

Assessment of fully digitalized workflow for implant-prosthetic rehabilitation in temporomandibular disorders patients: A clinical study

Digitalized workflow eliminates the need for the tray, impression materials, its decontamination, packaging and shipping, pouring with plaster, cast fabrication, mounting in an articulator, reducing storage spaces, and the risks of any loss or fracture of the plaster model is overcome by archiving on the computer. This clinical investigation aimed to evaluate the effectiveness of the fully digitalized rehabilitation [implant-supported prosthesis] method in partially edentulous patients and with TMD, using advanced software. Twelve patients requiring implant-supported prosthesis in the mandibular molar area with Temporomandibular disorders [TMD] were selected. The fully digitalized rehabilitation method with advanced software was used for rehabilitation. For each subject, Optical impressions, CBCT scan, and Digital recording of jaw movement data. Guided implant surgery and digitalized prosthetic rehabilitation; were performed. The effectiveness of the digitalized workflow was assessed by evaluating the changes in the joint symptoms before and after the end of the treatment, changes in the electromyographic tracings, the precision of the prosthetic artefact, assessed through the amount of chair adjustment operating time and the number of retouching/ modifications to be carried out before the completion of the work. The results showed that the mean operative time required in 12 patients was 9.42 min, significantly less than the time recorded in previous studies when the medium mean was 16.00 min. The mean number of touch-ups [adjustments] was less than 3, most of which were on the interproximal surfaces. There were no significant changes recorded in the electromyography tracings. There were also no changes in joint symptoms. It was found that this way of working was entirely reliable and significantly reduced operating times and the number of appointments. Digital flow is beneficial ei dysfunctional patients, not about improvements in temporomandibular symptoms but in times of operability and prosthetic retouching.

Restorative Space Analysis by Jaw Motion Tracking Using a Template in Completely Edentulous Patients

Improvements in computer-aided design/computer-aided manufacturing technologies have led to multiple attempts being made to simplify and improve the workflow of prosthesis fabrication for completely edentulous patients. However, most attempts still involve the conventional methods of impression-making and recording the maxillomandibular relationships using alginate, rubber impression materials, and wax materials. In the case of a completely edentulous arch, the presence of movable tissues and the absence of stable landmarks make it difficult to perform direct digitization using an intraoral scanner and to digitally determine the vertical dimension. In the alternative technique described herein, data are obtained by scanning a template such as the patient’s existing old dentures and jaw movement data using target materials and an optical scanner, and an appropriate maxillomandibular relationship that has the desired restorative space is determined on the basis of the obtained trajectory of mandibular movements while opening and closing the mouth. After designing dentures on the basis of the newly established maxillomandibular relationships and performing a try-in process, the final dentures can be manufactured. This alternative technique can reduce the need for multiple visits and complex procedures, improving the workflow for fabricating prostheses with the correct maxillomandibular relationships for individual patients.

Effect of an exclusion range of jaw movement data from the intercuspal positionon the estimation of the kinematic axis point

In patients who have lost natural occlusal contacts, the centric relation is usually estimated based on several anatomical factors such as the temporomandibular joint and masticatory muscles except dental arch. The clinical procedure to record the centric relation often depends on the clinician's expertise and technique; an objective method to determine proper occlusal position is desirable. The kinematic axis point (KAP) is kinematically estimated from sagittal movements and is an ideal posterior reference point that is used in dental articulators for reproducing jaw movement. Occlusal registration using the KAP may serve as a definite objective technique. The aim of this study is to investigate the effect of the exclusion range of sagittal jaw movement data from the intercuspal position (ICP) on the estimation of the KAP. The complete and incomplete sagittal border movement data of dentate subjects were used to estimate the KAPs. The locations of the estimated KAPs were compared. The results indicate that the incomplete sagittal border jaw movement data set does not include data points inside a 7mm distance from the ICP can be used for estimation of the KAP. In conclusion, the sagittal border jaw movement data around the ICP is not indispensable in the valid identification of the KAP.

Using Tongue, Lip, and Jaw Movement Data to Improve Diagnostic Accuracy of ALS

Using Tongue, Lip, and Jaw Movement Data to Improve Diagnostic Accuracy of ALS

Temporal coordination of sibilants in Polish onset clusters

In this study we employ the gestural syllable model to examine cluster-vowel timing in Polish sibilant initial (SI = {/∫m-, ∫p-, sp-, sk-/}) and sibilant final (SF = {/m∫-, p∫-, ps-, ks-/}) onset clusters. In this model, the timing of a complex onset is evaluated relative to a simplex onset and it is predicted that timing relations between onset and vowel should be invariant independently of onset complexity (Browman and Goldstein, 2000). Articulatory data of three speakers show that SI clusters conform to the predicted timing pattern in terms of a globally organized onset cluster relative to the vowel (“c-center”). This is compatible with previous findings for several languages. For SF clusters, however, there are considerable timing differences between complex and corresponding simplex onsets. This suggests that SF clusters are coordinated differently (and inconsistently) to the following vowel compared to SI clusters, as also reported previously for Romanian (Marin, 2013). We investigate to which extent this difference between SI and SF clusters is related to sibilants’ high coarticulatory resistance preventing a close C-V coordination. We will present an analysis of jaw movement data to consider possible effects of jaw position constraints on the temporal coordination of clusters.

Analysis of temporal variation in human masticatory cycles during gum chewing

ObjectiveThe study investigated modulation of fast and slow opening (FO, SO) and closing (FC, SC) chewing cycle phases using gum-chewing sequences in humans. DesignTwenty-two healthy adult subjects participated by chewing gum for at least 20s on the right side and at least 20s on the left side while jaw movements were tracked with a 3D motion analysis system. Jaw movement data were digitized, and chewing cycle phases were identified and analysed for all chewing cycles in a complete sequence. ResultsAll four chewing cycle phase durations were more variant than total cycle durations, a result found in other non-human primates. Significant negative correlations existed between the opening phases, SO and FO, and between the closing phases, SC and FC; however, there was less consistency in terms of which phases were negatively correlated both between subjects, and between chewing sides within subjects, compared with results reported in other species. ConclusionsThe coordination of intra-cycle phases appears to be flexible and to follow complex rules during gum-chewing in humans. Alternatively, the observed intra-cycle phase relationships could simply reflect: (1) variation in jaw kinematics due to variation in how gum was handled by the tongue on a chew-by-chew basis in our experimental design or (2) by variation due to data sampling noise and/or how phases were defined and identified.

A study of jaw coarticulatory resistance and aggressiveness for Catalan consonants and vowels

The goal of this study is to investigate coarticulatory resistance and aggressiveness for the jaw in Catalan consonants and vowels and, more specifically, for the alveolopalatal nasal //[symbol see text]/ and for dark /l/ for which there is little or no data on jaw position and coarticulation. Jaw movement data for symmetrical vowel-consonant-vowel sequences with the consonants /p, n, l, s, ∫, [ symbol see text], k/ and the vowels /i, a, u/ were recorded by three Catalan speakers with a midsagittal magnetometer. Data reveal that jaw height is greater for /s, ∫/ than for /p, [see text]/, which is greater than for /n, l, k/ during the consonant, and for /i, u/ than for /a/ during the vowel. Differences in coarticulatory variability among consonants and vowels are inversely related to differences in jaw height, i.e., fricatives and high vowels are most resistant, and /n, l, k/ and the low vowel are least resistant. Moreover, coarticulation resistant phonetic segments exert more prominent effects and, thus, are more aggressive than segments specified for a lower degree of coarticulatory resistance. Data are discussed in the light of the degree of articulatory constraint model of coarticulation.

Jaw movement and coronal stop spectra in Central Arrernte

This paper presents jaw movement data from two female speakers of Central Arrernte, focusing on the four coronal places of articulation (dental, alveolar, retroflex and alveo-palatal) across stop, nasal and lateral manners of articulation. It also presents spectral burst data for the stop consonants. Results suggest that when there is a clear spectral peak for the release burst, as is the case primarily for the alveo-palatal, but also for the alveolar and retroflex, the jaw remains high at stop release; but when the spectral burst has a relatively diffuse spectrum, as is the case for the dental, the jaw begins to lower before stop release in anticipation of the following vowel. In addition, there is evidence that the highest jaw target for the alveo-palatal is timed not for the release of the stop closure, but for the frication portion which follows. These results are interpreted as lending support for the view that the lower teeth play a role in stop burst release, similar to their role in sibilant fricative production. Finally, with regard to the retroflex consonants, there is evidence that the continuous upwards jaw movement during acoustic closure is associated with a low jaw position for the initial posterior placement of the tongue tip, followed by a final high jaw position at the anterior release of the tongue tip closure. These results support the view that both biomechanical and acoustic considerations play a role in speech planning and coarticulation.

Effect of occlusal contact stability on the jaw closing point during tapping movements

PurposeWe studied the relationship between tapping point reproducibility and stability of occlusal contacts at maximum intercuspation. MethodsTapping movements of 12 adult volunteers who had dentition with natural teeth were recorded, and distances between the tapping point (TP) and the intercuspal position (ICP) at the incisal point were calculated. Occlusal contacts at the ICP of individual subjects were also evaluated with black-colored silicone impression material. The correlation between TP–ICP distance and occlusal contact stability was studied. ResultsTP–ICP distance exhibited negative correlations with the total number of teeth showing occlusal contact at the ICP. Standard deviations of TP–ICP distance also negatively correlated with the extension of occlusal contact area over dentition. ConclusionsThis finding indicates that occlusal contacts at the ICP affect the kinematic behavior of tapping movements. The results of this study also suggest that jaw movement data may provide useful clinical information for the evaluation of occlusal contact at ICP.

A preliminary study of jaw movement in Arrernte consonant production

This study presents jaw movement data from Central Arrernte, an Australian Aboriginal language with six places of articulation in the stop series, including four coronal places of articulation. The focus of the study is on jaw consonant targets, and on the opening and closing movements of the jaw. As a point of comparison, data are also presented for English, a language with three places of articulation in the stop series. In line with previous results for English, jaw position in Arrernte is lowest for the velar /k/. The apico-post-alveolar (retroflex) /ʈ/, which is not found in English, has a jaw position almost as low as /k/. By contrast, the lamino-alveo-palatal /c/, which is also not found in English, has the highest jaw position. The remaining coronal consonants in Arrernte, /t/ (apico-alveolar and lamino-dental, respectively), show intermediate jaw positions, with differences between speakers. In terms of the kinematic measures examined (namely, variability in distance, duration and velocity of opening and closing movements), results show no consistent differences between English and Arrernte jaw movement.

A Precise and Useful Method for Coordinating Computed Tomography and Jaw Movement Frames of Reference

The aim of this study was to develop a means of coordinating helical computed tomography (CT)- based morphological data in 3 dimensions (3-D) with that pertaining to jaw movement as recorded by a device that measures jaw movement in six-degrees-of-freedom (6-DOF), thus producing multi-point movement analysis of the condyle. The study sample was two volunteers. One of the subjects had erosive bony changes in both condyles, while the other had healthy condyles. We employed a customized facebow, which enabled us to coordinate jaw movement data and morphological volume data from CT. Total uncertainty of the coordination was computed, according to International Organization for Standardization (ISO). In order to demonstrate the effects of multi-point analysis for complex condylar movement, we tried to visualize the trajectory of the working condyle in lateral excursion. The overall uncertainty at a condylar center chosen as an example to illustrate the method was 0.38 mm, 0.19 mm, and 0.50 mm in antero-posterior, lateromedial, and supero-inferior directions, respectively, in terms of 95% coverage as defined by the ISO. We developed facebow-based X-ray markers with high clinical operability, which could correlate the helical CT's coordinate system with our 6-DOF jaw movement measuring system for precise analysis of 3-D condylar movements. In motion analysis of rotational condyle, even a small amount of measurement error cannot necessarily be neglected. Then, a multi-point approach such as that realized by our system presents the best option.

Development of a novel articulator that reproduced jaw movement with six-degree-of-freedom

A novel robotic articulator that reproduced a six-degree-of-freedom jaw movement was developed and tested. A precise six-axis micro-positioning stage was employed for this articulator. A high-resolution jaw-tracking device measured the functional jaw movement of the patient and a six-axis micro-positioning stage reproduced recorded jaw movement data. A full veneer crown restoration was fabricated with this articulator system. A working cast was mounted on the positioning stage of the articulator. An occlusal table with soft wax was attached on the cast tooth die, and the jaw movements were reproduced to create a functionally generated path on the occlusal table. The finished occlusal record was used to obtain the wax pattern for the crown. In this subject, no intra-oral occlusal adjustment was necessary for setting the finished full veneer crown. Since this articulator could perform a precise reproduction of the dynamic jaw motion during the functional jaw movement, this system has potential to improve accuracy of the prosthetic teeth occlusion.

Analysis of sagittal condylar path inclination in consideration of Fischer's angle

This study investigated the sagittal condylar path during protrusive and lateral excursions by analysing the actually measured jaw movement data and re-evaluated the setting of the sagittal condylar path inclination in consideration of Fischer's angle. Protrusive and lateral excursions of 10 healthy subjects were measured using a three-dimensional mandibular movement analysing system. Condylar path inclinations at the hinge-axis point and the corresponding external point laterally extending from the condyle were evaluated in the sagittal plane. Fischer's angle was defined as the difference between the sagittal condylar inclinations during protrusive and lateral excursions on the non-working side, by keeping the corresponding horizontal distance from the intercuspal position (ICP) equivalent at the incisal point. Analysis was performed at three different magnitudes of excursions, where the incisal point was located at 1, 3 and 5 mm away from the ICP. There was no significant difference in the sagittal condylar path inclination or the Fischer's angle between two condylar reference points. However, they were significantly different across the three different magnitudes of excursions for both condylar reference points, i.e. sagittal condylar path inclination (P = 0.003 for protrusive excursion, and P < 0.001 for lateral excursion respectively; two-way repeated-measures anova), and Fischer's angle (P = 0.013, two-way repeated-measures anova) became smaller as the incisal point became distant from the ICP. Moreover, 3- and 5-mm eccentric positions were included in the 95% CI where Fischer's angle equals zero and were considered to be clinically acceptable to adjust the sagittal condylar inclination on the semiadjustable articulators.

Some articulatory details of emotional speech

Differences in speech articulation among four emotion types, neutral, anger, sadness, and happiness are investigated by analyzing tongue tip, jaw, and lip movement data collected from one male and one female speaker of American English. The data were collected using an electromagnetic articulography (EMA) system while subjects produce simulated emotional speech. Pitch, root-mean-square (rms) energy and the first three formants were estimated for vowel segments. For both speakers, angry speech exhibited the largest rms energy and largest articulatory activity in terms of displacement range and movement speed. Happy speech is characterized by largest pitch variability. It has higher rms energy than neutral speech but articulatory activity is rather comparable to, or less than, neutral speech. That is, happy speech is more prominent in voicing activity than in articulation. Sad speech exhibits longest sentence duration and lower rms energy. However, its articulatory activity is no less than neutral speech. Interestingly, for the male speaker, articulation for vowels in sad speech is consistently more peripheral (i.e., more forwarded displacements) when compared to other emotions. However, this does not hold for female subject. These and other results will be discussed in detail with associated acoustics and perceived emotional qualities. [Work supported by NIH.]

Segment sequencing and the jaw cycle

The open–close jaw cycle established in running speech often spans the articulation of several segments. Moreover, the extremes of the cycle are associated with opposing segment types, consonants and vowels, which form higher-level linguistic units, syllables, when grouped. The present study sought to determine how the syllable is related to the cycle. A partial relationship may imply that the jaw moves linearly from one segment to another. An isomorphic relationship that jaw movement is planned over the articulation of a group of segments, regardless of segment sequencing within the group. Five speakers repeated one of five syllable types (CV, VC, CVC, CCV, VCC) continuously for several seconds, producing an unbroken sequence of consonants and vowels. Jaw movement and acoustic data were recorded simultaneously and used to determine the temporal boundaries of the cycles and syllables, respectively. Cycle boundaries were defined by the points of maximum closure preceding and following an opening gesture, and syllable boundaries according to changes in frequency and amplitude corresponding to the onset of the initial and final segments in the syllable. A comparison of the relative boundary locations suggested an isomorphic relationship between cycles and syllables that interacted with segment type, syllable shape, and speaker.

Evaluation of the Stomatognathic Function in Children with the Jaw Movement Data in Six Degrees of Freedom

Evaluation of the Stomatognathic Function in Children with the Jaw Movement Data in Six Degrees of Freedom

Relationship between anteroposterior maxillomandibular morphology and masticatory jaw movement patterns

The causal relationships between oral function and craniomandibular morphology are poorly understood. The aim of this study was to determine whether quantifiable features of masticatory jaw movements and associated EMG activity correlated with variation in morphology as defined by the ANB angle. Thirty-six healthy subjects with no previous orthodontic treatment, asymptomatic masticatory muscles, and asymptomatic temporomandibular joints participated. While subjects chewed gum, jaw movement data and surface EMG data were digitized and then quantified into a 300 variable vector for each subject. ANB angle measurements were calculated from digitized tracings of lateral cephalographs. Step-wise linear regression and discriminant analyses were used to determine the relationship between the ANB angle and a subset of the variables defining jaw movement patterns and EMG patterns. A linear combination of seven jaw movements and EMG variables accounted for over 75% of the variation in the ANB angle (adjusted x R 2 = 0.78, P < .001). A jackknifed cross-validation of the discriminant analysis, which was forced to use the same seven variables as the regression analysis, resulted in correct classification of 14 of 20 skeletal Class I, 7 of 9 skeletal Class II, and 7 of 7 skeletal Class III subjects. These results suggest that there is an association between anteroposterior skeletal morphology, as quantified by the ANB angle, and masticatory jaw movement patterns, as quantified in this study. (Am J Orthod Dentofacial Orthop 1999;115:258-66)

Comparison of chin and jaw movements during gum chewing

Statement of problem. Knowledge of mastication is based on studies that use jaw tracking equipment in nonroutine settings. Ethologists would argue that such data probably does not reflect routine masticatory function. If jaw movements could be tracked noninvasively, then the hypothesis that jaw tracking equipment and nonroutine settings alter mastication could be investigated. Purpose. This study quantitatively evaluated the relationship between chin and jaw movements during a gum-chewing task. Material and methods. Masticatory chin and jaw movements of 50 subjects were tracked in the x-, y-, and z-axes for 15 seconds, which resulted in approximately 15 chewing cycles obtained per subject. For each chewing cycle, magnitude and timing of displacement, velocity, and acceleration extrema in each axis were computed for both jaw and chin movement data. Extrema means were calculated for each 15-second trial. The respective means representing chin versus jaw movements were compared with linear regression and correlation analyses. Results. All mean extrema were significantly correlated ( r range 0.30-0.99; P <.05). Magnitude correlations were larger than timing correlations for acceleration extrema. In contrast, magnitude correlations were smaller than timing correlations for displacement extrema. The highest correlation occurred for chewing rate. Conclusions. Chin and jaw movements were correlated during chewing; however, only chewing rate was highly predictable from chin movement data. (J Prosthet Dent 1999;81:179-85.)

Discriminant Analysis of Patterns of Jaw Movement During Rumination and Eating in a Cow

Discriminant analysis was used to identify combinations of variables, characterizing patterns of jaw movement (JM) during eating and rumination, that minimize errors when classifying series of successive JM of known behaviour into rumination and eating. JM data from a non-lactating jersey cow were recorded continuously for 72 h. The cow was fed 1800 g of barley straw and 1375 g of dried sugarbeet pulp pellets twice daily. Average times spent eating and ruminating daily were 294 and 462 min. Successive rumination and eating JM were grouped into series when pauses between JM were equal to or longer than a fixed time interval corresponding to the minimum time interval between successive rumination cycles. Time intervals between successive JM, amplitude (the magnitude of the jaw's movement) and number of chews per series of successive JM were calculated for all rumination and eating series and included in the discriminant analyses. The combination of the four variables, basic chewing rate (BCR), mean of amplitude/standard deviation of amplitude, ln(number of chews) and standard deviation of time intervals between successive jaw movements, gave the least minutes of misclassified chewing behaviour per day (3% of total daily chewing time) and yielded a quadratic discriminant function. The order of the variables mentioned rank the variables according to their ability to classify the series. Combinations of the variables BCR and ln(number of chews), and other variables based on mean and standard deviation of time intervals between successive JM and amplitude of JM, can be used with advantage for classifying series of successive JM into rumination and eating behaviour.