Relationship between habitual occlusal position and flat bite plane induced occlusal position in volunteers with and without temporomandibular joint sounds

The aim of this study was to assess whether temporomandibular joint (TMJ) sounds are associated with the difference between the habitual occlusal position (HOP) and the bite plane induced occlusal position (BPOP). Fifteen dental technician school students who had complete natural dentition, normal occlusion and who exhibited TMJ sounds were compared with fifteen healthy control subjects. HOP was recorded by voluntary jaw closing while in an upright position, and BPOP was recorded after wearing an anterior bite plane for a short period of time. Three interocclusal records were obtained in both positions with a vinyl polysiloxane material, and the recorded maxillomandibular relations were analyzed three-dimensionally and compared. Subjects with TMJ sounds had statistically larger differences between HOP and BPOP than controls (p<.05). Within this study population, an association was found between TMJ sounds and the difference between HOP and BPOP.     

The role of occlusal curvatures and maxillary arch dimensions in patients with signs and symptoms of temporomandibular disorders

Objective:To identify differences in occlusal curvatures and maxillary arch dimensions between subjects with signs and symptoms of temporomandibular disorders TMDs and asymptomatic subjects.Materials and Methods:One hundred subjects 78 female and 22 male who consented to participate in this research were examined for signs and symptoms of TMDs according to the guidelines of the Research Diagnostic Criteria for Temporomandibular Disorders RDCTMD. In addition, occlusal measurements were performed for all subjects on plaster models. All statistical analyses were performed with SPSS version 19.Results:Significant associations were revealed between the depth of the curve of Spee COS and temporomandibular joint TMJ sounds. Furthermore, maxillary arch width was negatively correlated to the steepness of the curve of Wilson. No differences were found between subjects with and without a history of orthodontic treatment.Conclusions:Subjects with TMJ sounds tend to have a flatter COS compared to subjects without TMJ sounds.     

Dental malocclusion is not related to temporomandibular joint clicking: a logistic regression analysis in a patient population

Objectives:To assess the association of several dental malocclusion features with temporomandibular joint (TMJ) click sounds in a population of temporomandibular disorder (TMD) patients.Materials and Methods:Four hundred forty-two TMD patients (72% female; 32.2 ± 5.7 years, range 25–44 years) were divided into a TMJ clicking and a no-TMJ clicking group, based on the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) assessment. Seven occlusal features were recorded for each patient: (1) posterior crossbite, (2) overbite, (3) open bite, (4) overjet, (5) mediotrusive and (6) laterotrusive interferences and (7) retruded contact position to maximum intercuspation (RCP-MI) slide length. A logistic regression model was created to estimate the association of occlusal features with TMJ clicking.Results:The difference between the groups as for the prevalence of the various occlusal features was generally not statistically significant, with minor exceptions. Mediotrusive interferences (P  =  .015) and RCP-MI slide ≥2 mm (P  =  .001) were the two occlusal features that were associated with the probability of having TMJ clicking, even if the adjusted odds ratios for TMJ clicking were low for both variables (1.63 and 1.89, respectively). Moreover, the amount of variance in the prevalence of TMJ clicking that was predicted by the final model was as low as 4.5% (R²  =  0.045).Conclusions:Findings from the present investigation suggested that in a population of TMD patients, the contribution of dental malocclusion features to predict TMJ click sounds is minimal with no clinical relevance.     

Incidence and prevalence of temporomandibular joint pain and dysfunction. A one-year prospective study of university students

Objective. The aims of this study were to investigate the incidence and recovery of temporomandibular joint (TMJ) pain and dysfunction during a 1-year period, and to examine factors associated with TMJ signs and symptoms. Material and Methods. The study population comprised 371 dental students examined at the start of education, out of which 308 were re-examined after 1 year. Case histories were collected with the aid of a questionnaire. The clinical examination involved TMJ mobility, TMJ pain, TMJ sounds, morphological and functional dental occlusion. Results. The 1-year incidence of TMJ signs and/or symptoms was 12%, with no statistically significant difference between men and women. Reported TMJ sounds (10%) and clinically registered TMJ pain (8%) reached the highest incidence rates. Approximately a quarter of those who had TMJ signs and/or symptoms at baseline had recovered at follow-up. Subjects with a non-symptomatic TMJ were significantly more often found among men and among those with bilateral contacts in centric relation, a normal transverse inter-maxillary relationship, and a stabile mandibular position in centric occlusion. Conclusion. The 1-year incidence of TMJ pain and/or dysfunction was high among 1st-year university students. The persistence of signs and symptoms during the observation period was related to gender, while incidence and disappearance of symptoms were not. Dental occlusion was not rejected as a possible concurrent factor in relation to TMJ pain and/or dysfunction among university students.     

牙列咬合特征与颞下颌关节紊乱综合征关系研究

目的    研究牙列咬合特征对颞下颌关节紊乱综合征（TMDs）的影响。方法    选择2013年11月至2014年11月于大连医科大学附属第二医院口腔科就诊患者及自愿参加本研究的学生共126例作为研究对象,按照有无TMDs症状分为阴性（28例）和阳性（98例）两组。根据颞下颌关节紊乱病双轴诊断（RDC-TMD）轴1诊断标准进行颞下颌关节（TMJ）检查,取牙列模型,对两组模型前牙覆牙合、前牙覆盖、后牙覆牙合覆盖和Spee曲线等4种主要的咬合特征进行测量,结果运用SPSS13.0软件进行分析。结果    正畸治疗史对于TMDs的发生并无显著影响（P > 0.05）;而前牙覆牙合、覆盖对TMDs发生均有一定影响（均P < 0.05）,后牙反牙合、锁牙合对TMDs症状无明显影响（P > 0.05）。无论左侧还是右侧,TMJ出现杂音者的同侧Spee曲线曲度均较TMJ无杂音者的同侧Spee曲线曲度明显减小,差异均有统计学意义（均P < 0.05）;TMJ肌肉群扪诊疼痛与否对Spee曲线曲度的影响均无统计学意义（均P > 0.05）。结论    前牙覆牙合、覆盖异常可能是TMDs发生的危险因素之一;TMJ出现杂音与Spee曲线的曲度有显著相关性,当Spee曲线较平直时,TMJ杂音的发生率相对较高。     

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??Objective    To identify differences in occlusal features between subjects with signs and symptoms of temporomandibular disorders and asymptomatic subjects. Methods    126 subjects who consented to participate in this research were examined for signs and symptoms of TMDs according to the guidelines of RDC-TMD. In addition??occlusal measurements were performed for all subjects on plaster models. The 126 patients were divided into the TMDs group and the no-TMDs group. Four occlusal features were recorded for each patient??overbite??overjet??posterior crossbite and the curve of Spee. All statistical analyses were performed with SPSS 13.0. Results    Significant associations were revealed between the curve of Spee and TMJ sounds. There were statistically significant differences between the TMDs group and the no-TMDs group in the overjet and overbite of inciors. No differences were found between subjects with and without a history of orthodontic treatment. The curve of Spee is not associated with pain of muscular origin or the posterior crossbite. Conclusion     The abnormal overjet and overbite could be occlusal risk factors for TMDs. Subjects with TMJ sounds tend to have a faltter curve of Spee compared to subjects without TMJ sounds.     

Temporomandibular joint sounds related to orthodontic therapy

A cross-sectional survey for temporomandibular joint (TMJ) sounds was conducted on 347 orthodontic patients before, during, and after treatment. Those patients who reported joint sounds, or in whom sounds were noted on clinical examination, were subjected to an audiovisual evaluation which was recorded on videotape to identify more precisely the character of the sounds during jaw opening and closing. TMJ sounds were quite common before, during, and after orthodontic treatment. There was a significant association among three variables: joint sounds, age, and treatment. It is not clear, however, whether joint sounds increased due to orthodontic treatment, age, or both. No significant associations were found between TMJ sounds and functional occlusal factors. Significantly more sounds were noted by the examiners than were reported by the patients. Medium or high amplitude sounds were evident in 32.6% of the 135 subjects who underwent the audiovisual examination.     

Occlusal contact area, occlusal pressure, bite force, and masticatory efficiency in patients with anterior disc displacement of the temporomandibular joint

The occlusal contact area, occlusal pressure, bite force, and masticatory efficiency were measured in 48 patients with anterior disc displacement (ADD) of the temporomandibular joint (TMJ). The results were compared with those of 30 normal controls without TMJ dysfunction. The values of occlusal contact area, bite force, and masticatory efficiency measured in patients with ADD were significantly smaller than those measured in the controls, although there was no difference in occlusal pressure between the two groups. The results of the measurements of 22 patients with ADD with reduction were also compared with those of 26 patients with ADD without reduction. There was no difference in any measurement between these patients subgroups. The analysis of occlusal contact area, bite force, and masticatory efficiency appeared to be useful methods in documenting the fact that masticatory function was impaired in patients with ADD of the TMJ.     

Association of symptomless TMJ sounds with occlusal force and masticatory performance in older adults

Summary  This study investigated associations between temporomandibular joint (TMJ) sounds and occlusal force or masticatory performance stratified by posterior occlusal supports in older Japanese adults. The subjects consisted of 1646 independently living people over 60 years. Masticatory performance, occlusal force, TMJ sounds and maximal mouth opening were examined. Posterior occlusal supports were classified by the Eichner Index. The prevalence of TMJ sounds was 27·7%, limitation of mouth opening (<40 mm) was 7·9% and TMJ pain was only 1·5%. In the Eichner C group, TMJ sounds were significantly associated with lower occlusal force (OR = 3·20, P  = 0·046) and lower masticatory performance (OR = 3·18, P  = 0·041) after controlling for gender and age. These associations were not found in the Eichner A and B groups. Within the limitations of this study, the presence of TMJ sounds, even if they were symptomless, was associated with impairment of masticatory function in older adults with reduced occlusal support.     

Morphometric analysis for evaluating the relation between incisal guidance angle,occlusal plane angle,and functional temporomandibular joint shape variation

Objective: The correlations between morphology of the temporomandibular joint structure, the anterior guidance angle, and occlusal plane were investigated.

Materials and methods: A cone beam computed tomography analysis was performed in 158 patients (86 women and 72 men). 3D software was employed to obtain the coordinates of the shape of the incisal guidance angle, occlusal guidance angle, articular fossa, and mandibular condyle. Generalized Procrustes analysis including principal components analysis (PCA) were performed and produced principal components (PCs) scores of each shape and their centroid size (CS).

Results: A significant Pearson correlation coefficient of 0.3451 (p?Conclusions: Incisor guidance angle and occlusal plane angle were correlated. In addition, there was a correlation between CS and incisal guidance angle. In the PCA, It can be concluded that the size is more related to the incisor guidance angle than the morphological factors of the constituent components of the TMJ.     

Correlation of the characteristics of temporomandibular joint and tooth contact sounds

In this study tooth contact sounds have been compared with temporomandibular joint (TMJ) sounds elicited during opening and closing movements. One hundred and eight subjects were instructed to open as far as possible and then close with sufficient force to produce a tooth contact sound. At least four cycles from each subject were recorded on tape, The first and last sounds in the recording were the tooth contact sounds, these were identified automatically. The mean duration and rise time of each tooth contact sound was calculated and their standard deviations for each subject were calculated to give a measure of the reproducibility. The number and mean amplitude of TMJ sounds occurring during tooth separation were also calculated for each cycle. Highly significant correlations were found between the number and amplitude of the TMJ sounds within a cycle and the duration and rise time, and particularly their standard deviations. Acoustic quiescence during the open–close cycle was associated with short, reproducible tooth contact sounds characterized by a short rise time. The longest and most variable tooth contact sounds were associated with TMJ sounds in all three phases of the open–close cycle. This supports previous clinical findings associating occlusal interferences with TMJ dysfunction.     

The Position of the Occlusal Plane in Natural and Artificial Dentitions as Related to Other Craniofacial Planes

Purpose: This study aimed at determining the most reliable ala‐tragus line as a guide for the orientation of the occlusal plane in complete denture patients by use of cephalometric landmarks on dentate volunteers. Materials and Methods: Analysis was made for prosthodontically related craniofacial reference lines and angles of lateral cephalometric radiographs taken for 47 dentate adults. Variables were determined and data were analyzed using SPSS (SPSS, Inc., Chicago, IL). Results: Occlusal plane angle formed between the occlusal plane and Camper's plane had the lowest mean value in the angle formed with Camper's I, which represents the measure taken from the superior border of the tragus of the ear with a score of 2.1°. The highest was measured in the angle formed with Camper's III with a score of 6.1°, while the angle formed with Camper's II was 3.2°. The differences between the three planes in relation to the occlusal plane was significant (p < 0.001). Conclusion: The superior border of the tragus with the inferior border of the ala of the nose was most accurate in orienting the occlusal plane.     

Occlusal Plane Orientation: A Statistical and Clinical Analysis in Different Clinical Situations

Purpose: Orientation of the occlusal plane is important in a number of clinical situations. Using the reported soft and hard tissue landmarks is difficult and requires experience, as the landmarks are located on the face or by use of a cephalometric radiograph. Improper use of these landmarks may compromise the functional and esthetic result of prosthetic restorations. This study evaluated the reliability of the hamular notch/incisive papilla plane (HIP) in establishing the occlusal plane. Materials and Methods: Ninety healthy, Indian adults (60 dentate, 30 edentulous) participated in this study. The occlusal plane of the subjects was compared with their HIPs. In dentate subjects, the maxillary stone cast was mounted on the Wills surveyor with HIP, which was made parallel to the horizontal plane using the tripoding method. The vertical distance between the occlusal plane and floor of the surveyor was measured at four points. When the measured values were equal, the two planes were confirmed to be parallel for that situation. In turn, this relation confirmed the parallelism between the occlusal plane and HIP. In the edentulous subjects, the occlusal plane, established clinically using the ala tragal line, was compared with the HIP radiographically using lateral cephalograms. Paired t‐test was used to test the equality of the mean differences at a 0.05 significance level. Results: The mean differences from the right canine were: 0.055 cm at the left canine, 0.05 cm at the right molar, and 0.065 cm at the left molar in dentate subjects and 0.001 cm between the incisive papilla and hamular notch in edentulous subjects. The HIP appeared parallel to the occlusal plane as the paired t‐test showed no statistically significant difference (p > 0.05). Conclusion: In the population tested, the HIP was parallel to the occlusal plane. Therefore, this may be a viable reference in complete denture prosthodontics.     

Occlusal plane orientation in Klinefelter syndrome (47, XXY males)

summary Occlusal plane position was analysed cephalometrically in 35 Klinefelter adults (47, XXY) and compared with 60 eugnath control males (46, XY).The significantly smaller angles between the occlusal plane and the cranial base (NSL-OLs) and between the occlusal plane and the Frankfort horizontal plane (Fr-OLs) were obtained in 47, XXY males ( P < 0.0l), while the angles between the maxillary base and the occlusal plane (NL-OLs) and between the Camper's line and the occlusal plane (Camp.-OLs) were not significantly different ( P > 0.05) from the control group. Significantly smallelr angles between the occlusal plane and the cranial base (NSL-OLs) and between the occlusal plane and the Frankfort horizontal plane (Fr-OLs) in Klinefelter males are attributed to the hereditary influence of an extra X chromosome on the smaller growth of the cranial base and the greater growth of the lower border of the mandible. Although the maxilla was also shifted forward in XXY males in relation to the cranial base it was not enough to compensate for the hereditary influence, due to the greater growth of the lower border of the mandible and the smaller cranial base in 47, XXY males, on the inclination of the occlusal plane to the Frankfort horizontal plane and the cranial base. The forward shift of maxilla was sufficient to compensate for the inclination of the occlusal plane in 47, XXY males to the maxillary base and the Camper's line ( P > 0.05).     

“Occlusal Plane Orientor”: An Innovative and Efficient Device for Occlusal Plane Orientation

Correct occlusal plane orientation is a prerequisite in Prosthodontic reconstructive treatment therapy as it helps in achieving esthetics and phonetics anteriorly and forms a milling surface posteriorly where tongue and buccinator muscle position the food bolus during mastication. Activity of Muscles during clenching will be least, when the occlusal plane is made parallel to plane of lost natural teeth. Conventionally the ala-tragus line (Camper’s plane) is used as a guide for assessment of the occlusal plane and fox plane is used to check the parallelism between the two. Occlusal plane orientor is a new device developed to mark occlusal plane parallel to ala-tragus line on maxillary occlusion rim, thereby saving clinician’s time and increasing efficiency. Additionally, it is a useful tool for occlusal plane orientation in patients with facial deformity, absence of an eye or an ear.     

Effect of occlusal plane control procedure on hyoid bone position and pharyngeal airway of hyperdivergent skeletal Class II patients

Objective:To evaluate the effect of occlusal plane control on the hyoid bone position and pharyngeal airway of hyperdivergent skeletal Class II patients during orthodontic treatment.Materials and Methods:Cephalograms of 47 hyperdivergent skeletal Class II subjects with occlusal plane control (OPC), and another 50 subjects without occlusal plane control (NOPC) were selected to compare the effects of the occlusal plane control procedure. Lateral cephalograms before treatment (T1), immediately after treatment (T2), and an average of 12 months after treatment (T3) were obtained, and 17 measurements were analyzed in each group and compared between groups.Results:With respect to the T2−T1 changes, the sagittal discrepancies in both groups were alleviated. In the OPC group, both the occlusal and mandibular plane angles decreased, accompanied by anterior and superior movement and counterclockwise rotation of the hyoid bone. The overall changes from T3 to T1 in each group exhibited trends similar to that induced by treatment. As for pharyngeal airway space alterations, no significant difference in OPC group was presented throughout treatment or retention periods.Conclusions:The customized occlusal plane control procedure was effective for hyperdivergent skeletal Class II patients: The occlusal plane rotated counterclockwise, followed by a counterclockwise rotation of the mandibular plane. The hyoid bone moved anteriorly and superiorly, accompanied by its counterclockwise rotation. However, this procedure did not induce significant alteration of the pharyngeal airway space.     

The relationship between condylar guidance and temporomandibular joint clicking

The association between condylar inclination and temporomandibular joint (TMJ) clicking was tested by measuring the angles of condylar guidance in the sagittal plane during opening and closing movements in 12 subjects with temporomandibular joint clicks and 16 subjects without TMJ clicks. Each subject had tracings made by using a customized functional clutch. All subjects had full dentition and were without symptomatic mandibular dysfunction. Condylar inclinations were measured in parasagittal tracing planes. The travel path of the hinge axis of the condyle's movements was recorded, directly formed, and compared with a four-component axiograph recording that used the axis-orbital plane as a reference for the subjects. The measurements of angles along several distances (millimeters) of condylar guidance from the axis-orbital plane were obtained and evaluated. The measurements were made in the sagittal plane and through opening-closing movements starting from the actual occlusal vertical dimension of each subject. The results do not support the hypothesis that mean angles of the condylar guidance are significantly different in the group with TMJ clicking compared with the group without TMJ clicking.     

Effect of Molar Occlusal Balance on Cognitive Function in the Elderly

BackgroundElderly people with dementia, who are increasing at a rate comparable to the rate at which theelderly population is growing, are becoming a serious social problem in Korea. Therefore, the purpose of this study was to investigate the association between molar occlusal balance and cognitive function among Koreans aged 65 years and older.MethodsA total of 308 participants aged 65 years and older who attended a senior center were recruited for the study with their consent. The Korean version of the Mini-Mental State Examination (MMSE-DS) was used to assess cognitive function, and masticatory ability was measured according to the ability to chew food, the number of remaining teeth, and the self-perceived perceived masticatory function. Relative molar occlusal balance was measured using the T-scan Ⅲ system. All collected data were analysed using SPSS version 23.0.ResultsThere was a significant association between cognitive function and molar masticatory ability (P < .05). The participants with relative molar occlusal balance had a higher MMSE-DS score when compared to those with relative incision occlusal balance, adjusted for sociodemographic factors and number of remaining teeth, subjective masticatory ability, chewing ability, occlusion time, and denture use. Cognitive function was higher when relative molar occlusion was greater compared to anterior occlusion in anterior-posterior teeth balance.ConclusionsCognitive function in elderly people was higher when the relative molar occlusal balance was greater. Mastication with posterior teeth may have a more important effect on stimulation of cognitive function. Therefore, oral health care focusing on maintenance of molar teeth may be crucial for elderly persons.     

Morphological and positional assessments of TMJ components and lateral pterygoid muscle in relation to symptoms and occlusion of patients with temporomandibular disorders

Disc displacement is accepted as one of major findings in temporomandibular disorders (TMD). However, the associations of disc positions with morphological and positional changes of temporomandibular joint (TMJ) components and lateral pterygoid (LP), TMD clinical symptoms, and occlusion have rarely been discussed quantitatively. In this study, the morphological and positional changes of TMJ components and LP were assessed by means of magnetic resonance imaging (MRI) and tomography of the TMJ in 41 TMD and nine control (CN) subjects. Disc positions in TMD subjects were divided into normal position (NP) and anterior displacement with and without reduction (ADR+ and ADR-, respectively). From MRI scans and tomograms, the morphological and positional changes of TMJ components and LP were measured and compared among CN, NP, ADR+ and ADR- groups. Correlations between these measurements and the scored clinical symptoms and occlusal factors were analysed in TMD subjects. The results indicated that: (1) TMJ osseous structures and LP showed no significant difference among CN and the three TMD groups, except for a posterior seat of condyle and shorter/steeper condylar movement during jaw opening; (2) disc length and inclination were significantly shorter and steeper, respectively, in ADR+ and ADR-; (3) disc positions were not specified by clinical symptoms and occlusal factors, except for the dominant TMJ sounds in ADR+; (4) an uncoordinated movement of the condyle/disc complex was found in ADR+ and/or ADR-; (5) TMJ osseous structures and the disc were weakly associated with clinical symptoms and occlusal factors. However, the LP showed negative associations with palpable pain for both the TMJ and jaw muscles and the static occlusal factors. These findings suggest that TMJ internal derangements are more related to the positional changes or spatial relationships of TMJ components but less to the individual morphologies of TMJ osseous structures, disc and LP, as well as specific clinical symptoms and occlusal factors, which might be in disagreement with a large body of previous statements.     

A comparison of the signs of temporomandibular joint dysfunction and occlusal discrepancies in a symptom-free population of men and women

To date, there has been no conclusive explanation for the predominance of female patients with temporomandibular joint (TMJ) dysfunction. The purpose of this study was to survey a normal population without symptoms for the presence of certain putative signs of TMJ dysfunction in association with certain signs of occlusal discrepancy and to determine the presence of any gender variation. The subjects (217 men and 217 women) were examined for the presence of three putative signs of TMJ dysfunction: limited mandibular opening (under 37 mm), deviation on opening, and joint sounds. The subjects were also examined for the presence of four signs of occlusal discrepancy: an anterior slide from centric relation (CR) to centric occlusion (CO), lateral slide from CR to CO, nonworking occlusal contacts, and working disclusive contacts distal to the canines. CR is the mandibular position at which the condyles are in their most superior position on the posterior aspect of the articular tubercles. CO is the mandibular position at which the mandibular and maxillary teeth are in maximum intercuspation. There were no significant differences in the prevalence of the putative signs of TMJ dysfunction and occlusal discrepancy between men and women. It was concluded that factors other than the presence of these signs of TMJ dysfunction and occlusal discrepancy are responsible for the high predominance of female patients with TMJ dysfunction.