Relationship Between Habitual Occlusal Position and Flat Bite Plane Induced Occlusal Position in Volunteers With and Without Temporomandibular Joint Sounds

Abstract

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.     

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.     

(牙合)垫治疗低位咬合的髁突位置变化研究

目的:观察垫治疗低位咬合的疗效.方法:对因严重磨损、伴颞下颌关节紊乱症状的低位咬合患者13例,用(牙合)垫恢复其正常垂直距离.于戴用(牙合)股垫前、后及戴用后半年,摄双侧闭口薛氏位片,行关节间隙的测量,并作统计学处理.结果:戴用(牙合)垫后关日前间隙减少单资2.07mm,后间隙及上间隙分别增加1.11mm、0.51mm,有显著性差异 半年复查结果与戴用(牙合)垫后相比,关节间隙改变则无显著性差异(P>0.05).结论:(牙合)垫通过恢复正常的垂直距离,使髁突向前下移位,并稳定于关节内位置正常,恢复了牙、肌肉、关节的协调关系.     

Influences of changing vertical dimension, occlusal contacts of bite plane and body position on masticatory muscle activities

The Bite plane therapy has been accepted to be useful for treatment of the patients with the stomatognathic dysfunction. The purpose of this study is to make clear the influences of changing the vertical dimension and occlusal contacts of the bite plane on masticatory muscle activities in order to improve the bite plane therapy. The full arch bite plane with an interincisal distance of 5 mm was fabricated for each one of 30 subjects without stomatognathic dysfunction. The EMG activities were recorded from the anterior part of the temporal muscles, the masseter muscles and the anterior belly of the digastric muscles bilaterally while the subject exerted tapping and maximal voluntary clenching in a postural position. Four kinds of experiments were performed as follows. In Exp. 1, integrated EMG activities of each muscle were compared with and without the bite plane. In Exp. 2, the influences of changing the vertical dimension of the bite plane (2.5 mm, 5 mm and 7.5 mm) were tested in 17 subjects. In Exp. 3, the influences of changing the location of occlusal contacts of the bite plane were studied in 12 subjects. In Exp. 4, the influence of changing the body positions on EMG activities and mandibular positions was compared in 30 subjects between the sitting and supine positions. Furthermore, the influence of the same factor was compared with and without the bite plane which was adjusted in each position. The results were summarized as follows: 1. Wearing the bite plane mainly reduced activities of the temporal muscles. 2. The bite plane with an interincisal distance of 5 mm was most effective in reducing activities of the temporal muscles. 3. Wearing the bite plane with anterior occlusal contacts reduced activities of the elevator muscles significantly. 4. Significant differences in activities of the temporal and digastric muscles were recognized between the two body positions when the bite plane was not applied. However, no significant difference was recognized when the bite plane was inserted. Furthermore, those differences were correlated with the difference in the antero-posterior mandibular displacement between the two body positions while the subject tapped the teeth. These results suggest the possibility to control masticatory muscle activities by applying the bite plane with the proper vertical dimension and occlusal contacts. In addition, it is necessary to take a suitable body position for the patient who has a difference in the mandibular displacement between the sitting and supine positions when applying the bite plane.     

减小后牙▉平面倾斜度对安氏Ⅱ类高角畸形髁突位置影响的研究

目的: 研究在安氏Ⅱ类高角畸形正畸治疗中,减小后牙平面倾斜度对髁突位置的影响。方法: 15例安氏Ⅱ类高角畸形患者,年龄15~30岁。治疗前ANB>5°,下颌平面角FH-MP>32°,磨牙关系为双侧远中关系。常规排齐整平及适当扩弓后,利用多曲唇弓导下颌向前,并使后牙平面平坦化。利用锥形束CT（cone-beam CT,CBCT）测量治疗前、后颞下颌关节前、上、后间隙及后牙平面的改变情况。采用SPSS19软件包对变化量进行t检验;并利用相关性分析,进一步探讨髁突位置改变量与后牙平面倾斜度减小量之间的相关性。结果: 所有患者磨牙尖牙关系均调整到中性,侧貌改善明显,髁突后间隙平均增加(0.88±0.17)mm,变化有统计学意义(P<0.001);髁突上间隙平均增加(0.45±0.20)mm,变化也具有统计学意义(P<0.05)。后牙平面变平坦,POP-SN及POP-FH平均减小3.59°±2.31°及2.31°±3.62°,变化具有统计学意义(P<0.001)。髁突前间隙变化量无统计学意义,髁突位置改变量与后牙平面倾角的变化量之间无显著相关性。结论: 在安氏Ⅱ类高角畸形患者的正畸治疗中,通过正畸减小后牙平面倾斜度,可使髁突的位置发生适当的前下改变,有利于关节症状的改善。     

Temporomandibular joint vibration before and after exercises and occlusal splints

Temporomandibular joint (TMJ) sounds are frequent in patients. The aim of this study was to analyze patients with clicking at the end of opening and at the beginning of closing their mouths treated by muscular exercises through chewing and by occlusal splints. Fifteen patients with clinically verified clicking and TMJ and 15 patients without sounds were selected by the Research Diagnostic Criteria for Temporomandibular Disorders. They were submitted to electrovibratography at consultation and 60 and 120 days of treatment by occlusal splints and exercises. Patients demonstrated significant reduction of TMJ sounds after treatment, but vibration intensity was not similar with that of the control group after 120 days.     

The position of the occlusal plane in dentulous subjects with various skeletal jaw-relationships

This study was conducted to examine the level and inclination of the occlusal plane in dentulous subjects with various skeletal jaw-relationships with the purpose of finding more reliable guides for locating the occlusal plane in edentulous patients. The investigation was carried out on 140 lateral cephalometric radiographs of young people with natural teeth in the intercuspal position. The sample was divided into three groups according to the skeletal relation of the jaws. The occlusal plane in this study and the two reference planes (maxillary and mandibular plane) were established according to the cephalometric criteria of Schwarz. On each radiograph both the angulation and the perpendicular distance of the occlusal plane to the reference planes were recorded and the values of the obtained data were subject to statistical analysis. The selected mean values of the angles and linear distances between the occlusal plane and reference planes calculated on the probability level of 95% could be used as cephalometric indicators for the locating or correcting the position of the occlusal plane in the prosthetic treatment of edentulous patients.     

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.     

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.     

Evidence of an influence of asymmetrical occlusal interferences on the activity of the sternocleidomastoid muscle

To investigate the hypothesis of a functional coupling between occlusion and neck muscles, the immediate effect of asymmetrical occlusal interferences on the pattern of contraction of the sternocleidomastoid muscles (SCM) during maximum voluntary clench (MVC) was analysed in 30 healthy subjects. All subjects had a complete and sound permanent dentition, without temporomandibular joint (TMJ) and craniocervical disorders. A 5-s surface electromyogram (EMG) examination of the SCM was performed during (1) MVC in intercuspal position and (2) MVC with a single 200-microm occlusal interference alternatively positioned on teeth 16, 13, 23, 26. All subjects had a symmetrical EMG activity during MVC in intercuspal position. For each subject, SCM potentials were standardized as percentage of the mean potentials recorded during the MVC on natural dentition and the EMG waves of left- and right-side muscles were compared by computing the relevant percentage overlapping coefficient (POC). For each subject, the best and the worst POCs computed during the four MVC tests with occlusal interferences were found and the percentage difference between them was calculated. In the four MVC tests with occlusal interferences, SCM symmetry was very different from that recorded during MVC on natural dentition. The difference between the best and worst POCs computed within each subject was very variable, ranging from 1.52 to 41.57%. In conclusion, when young healthy subjects with a normal occlusion clench on an asymmetrical occlusal interference, they have an altered left-right side pattern of contraction of their SCM. In almost all subjects, a previously symmetrical pattern became asymmetrical.     

A technique for evaluation of centric relation tooth contacts. Part II: Following use of an occlusal splint for treatment of temporomandibular joint dysfunction

The purpose of this study was to determine the effect of TMJ dysfunction on the recording of centric relation. Centric relation was recorded using an anterior occlusal stop and by bimanual manipulation. Changes in occlusal contacts were recorded before and after occlusal splint therapy in six subjects with TMJ dysfunction. The pantographic reproducibility index and clinical signs and symptoms were used to determine the presence or absence of dysfunction. Use of the anterior occlusal stop resulted in a more posterior, superior initial tooth contact position when compared with bimanual manipulation. Occlusal contact positions were less consistent in TMJ dysfunction subjects than in control subjects. Initial occlusal contacts changed toward centric relation as the dysfunction disappeared. Final occlusal contact was found on the side where clinical signs and symptoms occurred. The condyle on the affected side appeared to be repositioned posteriorly and superiorly in most instances. Occlusal splint therapy was more effective when the splint was adjusted weekly. This study indicates the need to eliminate TMJ dysfunction before recording centric relation or adjusting the occlusion. Occlusal interferences found with TMJ dysfunction are not the same as occlusal interferences found when TMJ dysfunction is absent. Abnormal features on pantographic tracings may aid in indicating the presence of occlusal interferences. Occlusal adjustment in the presence of TMJ dysfunction would result in erroneous occlusal reduction.     

Patients with restored occlusions. Part III: The effect of occlusal splint therapy and occlusal adjustments on TMJ dysfunction

An earlier study of 50 patients with occlusions restored by fixed partial dentures indicated a high percent (68%) of TMJ dysfunction. Occlusal interferences can play a significant role in causing TMJ dysfunction. To determine the significance of occlusal interferences, occlusal splints were placed in 10 of these restored patients who had moderate to severe dysfunction. The PRI was used to detect the presence or absence of TMJ dysfunction. The PRI TMJ dysfunction scores were reduced in all 10 patients after use of the occlusal splint. Five of the patients achieved reproducible tracings (no TMJ dysfunction) during the experiment time of 7 months. The occlusion of two patients was adjusted to eliminate the need for the occlusal splint. Patients who wore the splint 24 hours a day showed a significant (0.0004 level) reduction in TMJ dysfunction. Those patients who did not wear the splint regularly or had high levels of stress had PRI scores that varied. This finding indicates that the occlusal splint is not a treatment, as its removal permits reactivation of the occlusal interference. Resolution of dysfunction did not occur until occlusal interferences were removed. The changes in PRI scores to different dysfunction categories (none, slight, moderate, and severe) for the experimental group were significant at the 0.01 level. A control group of five patients had similar pantographic tracings but no other treatment. Their PRI scores varied, but there was no significant change in PRI scores or dysfunction categories.It was concluded that occlusal interferences were active causes of TMJ dysfunction in 10 of 36 patients in a population with restored occlusions.     

Unilateral temporomandibular disorder and asymmetry of occlusal contacts

STATEMENT OF PROBLEM: The relationship between temporomandibular disorders and occlusal tooth contacts is unclear and controversial. PURPOSE: This study assessed whether unilateral temporomandibular disorders were associated with the absence of bilateral symmetry in the number of occlusal contacts. MATERIAL AND METHODS: Fifteen university dental students who had complete natural dentition and normal occlusion and exhibited unilateral signs and symptoms of temporomandibular disorders were compared to 15 age- and sex-matched healthy control subjects. All participants met specific inclusion and exclusion criteria. Occlusal contacts were recorded in the intercuspal position with wax registrations. Dental impressions were made and poured in type I stone. Contacts were classified according to location and intensity. Four experienced dentists using an established protocol made all measurements. Assessment of the reliability of the occlusal registration procedure showed a small (<4%) within-subject variability. Statistical analysis was based on the binomial distribution and nonparametric tests (P < .05). RESULTS: Subjects with unilateral temporomandibular disorders had greater bilateral difference in the number of contacts than controls. The median (95% confidence interval) difference was 3 (2 to 4) and 2 (1 to 2), respectively. In unilateral temporomandibular disorder subjects, the number of occlusal contacts was greater on the side with, rather than without, disorder (median number 20 vs. 16). The median (95% confidence interval) difference between sides with and without unilateral temporomandibular disorders was 3 (2 to 4) for all contacts and 2 (1 to 3) for contacts on the posterior teeth. CONCLUSION: Within the population of this study, a weak association was found between unilateral temporomandibular disorders and asymmetry in the number of occlusal contacts.     

Maintenance of condylar position using an occlusal splint after mechanical vibrating-traction of the TMJ

Although adequate relief of excess mechanical loading to the joint has been accepted as one of the important treatment concepts in the orthopaedic field, a treatment method for the temporomandibular joint (TMJ) to relieve excess mechanical loading has not yet been established. This study aimed to clarify the effect of an occlusal splint on the maintenance of the distracted condylar position achieved by vibrating-traction method. Vibrating dynamic traction force was applied for 5 min to the right TMJ using vibrating-traction apparatus. A flat stabilization splint was adjusted to keep the mandibular position and the condylar displacement was evaluated for 6 h after the dynamic traction procedure. Mean vertical displacement of the mandibular right first molar immediately after the vibrating-traction for the six subjects was 156 microm (ranging from 141 to 179 microm). The calculated mean condylar displacement immediately after the traction was 480 mum and could be kept to be 381 mum even after 6 h by wearing the flat stabilization splint. From the results of this study, it was revealed that the mechanically tracted condylar position could be maintained by a flat occlusal splint. It was suggested that the vibrating-traction method followed by the provision of occlusal support might have a possibility to work as a mechanical relieving procedure for the TMJ.     

A long-term epidemiologic study of the relationship between occlusal factors and mandibular dysfunction in children and adolescents

A longitudinal investigation of changes of signs and symptoms of mandibular dysfunction over four to five years was performed, by means of questionnaires and clinical examination, in 240 children, ages 7, 11, and 15 years at the first examination. The objective of this part of the study was to analyze correlations between some occlusal and other factors, and mandibular dysfunction. Signs and symptoms of mandibular dysfunction increased slightly in both frequency and severity but were judged to be mild in most cases. Several types of occlusal interference were frequently recorded at both examinations. Dental wear increased during the follow-up period, while the results of evaluations of motor activity and psychological traits were relatively constant. There were only a few significant correlations, most of which were weak, between the recorded variables and mandibular dysfunction, and those found were not consistent in all age groups. TMJ sounds were positively correlated with lateral deviation of the mandible between retruded contact and intercuspal position in all age groups. An attempt to analyze the longitudinal relationship of occlusal interference with signs and symptoms of mandibular dysfunction did not reveal any strong correlations. The results are interpreted as supporting the heterogeneous and multifactorial nature of functional disturbances of the masticatory system.     

Application of occlusal splint for the patient with temporomandibular joint dysfunction. An application of silane coupling treatment: a case report

The bite plane therapy has been one of the most useful treatment methods for patients with temporomandibular joint (TMJ) dysfunction. But the bite plane usually causes esthetic and articulation disturbances and it is occasionally difficult to use during mastication. The authors have fabricated a new type of bite plane, named occlusal splints, which covers each side of the premolars and molars. The occlusal splint was constructed by a hard-resin for the occlusal part and cast clasps for the retentive part and these parts were adhered after a pre-treatment of metal by the use of a silane coupling agent (Silicoater system). The patient was a 35 year-old man, with a chief complaint of left side reciprocal TMJ clicking. The anterior repositioning type of bite plane was applied for the treatment with the diagnosis of anterior disk displacement with reduction. But he complained of esthetic and articulation disturbances especially during working and eating. After four months we fabricated an occlusal splint that can be used for a long period of time. The patient was satisfied to use this occlusal splint and no symptoms of TMJ dysfunction were found with this appliance. It is suggested that the occlusal splint consisting of a hard-resin and cast clasps is a useful appliance especially for the purpose of use during working and eating, and for evaluating the properness of mandibular position.     

A clinical study on occlusal plane in relation with orofacial morphology and stomatognathic function

Occlusal plane is one of the important and fundamental factors that establish the mandibular position and the form of dental arch and prosthesis. The aim of this study is to investigate the morphological and functional importance of occlusal plane in relation with orofacial morphology and stomatognathic function. Cephalograms were taken and electromyograms of masseter, anterior and posterior temporal muscles were recorded during clenching, tapping and chewing movements in 30 normal young adult subjects. Mandibular movements were simultaneously recorded using Sirognathograph (Siemens, West Germany). A correlation analysis was performed to study the relationship between the occlusal plane and morphological and functional parameters. As a result, the occlusal plane angle showed; 1) close correlations with the mandibular plane angle, Camper's plane angle and palatal plane angle, 2) correlations with the duration of activity of anterior temporal muscles and the sagittal angle of chewing pathway. The results suggest that there is a close relationship between the occlusal plane and orofacial morphology. Furthermore, the morphological parameters closely related to the occlusal plane were found to affect stomatognathic function. It is concluded that the occlusal plane is the important factor which harmonizes morphology and function of the stomatognathic system.     

Lengths of condylar pathways measured with computerized axiography (CADIAX®) and occlusal index in patients and volunteers

The lengths of the condylar pathways during protrusive and opening movements were investigated with computerized axiography in 100 individuals. Forty‐two patients suffering from anterior disk displacement with reduction (ADD) in one or both temporomandibular joints (TMJ) and 28 patients with anterior overrotation clicking (AOC) of the TMJ were compared with 30 asymptomatic volunteers. Patients suffering from ADD showed significantly shorter tracings than did the two other groups. A significant difference of length of TMJ movement between men and women was found only in one group. The occlusal indices (OI) of the three groups were assessed and compared with each other. Here, a significant difference was found between volunteers and patients suffering ADD and between volunteers and patients with AOC. Between men and women a significant difference of the OI was found in the group with AOC, women presenting higher scores than men. Except for the group of patients with ADD, who showed shorter average lengths, volunteers as well as patients with AOC, were within the normal limits given in the literature for TMJ movement lengths recorded with axiography. The results of this examination therefore indicate that when considering movement length alone no discrimination between healthy and diseased TMJ can be made.     

Influence of altered occlusal plane on rabbit temporomandibular joint cartilage

Background:  There is limited knowledge relating to the influence of mechanical stress on the temporomandibular joint (TMJ) and the degree of damage this stress can induce in the case of an altered occlusal plane on the extracellular matrix cartilage and chondrocytes. The aim of this study was to examine the histopathological influence of an altered occlusal plane on rabbit TMJ cartilage.
Methods:  Fifteen male Japanese white rabbits were used in this study. In 12 cases, the upper right and lower left teeth were ground to their cervical level so that the occlusal plane was tilted right side up. Their temporomandibular joints (TMJs) harvested at 3 days, 1, 2 and 4 weeks were analyzed immunocytochemically and immunohistochemically. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick endlabeling (TUNEL) method was used for immunocytochemical study to detect DNA fragmentation in chondrocytes. An immunohistochemical study was also performed to evaluate the metabolism of type 2 collagen in the extracellular matrix in the TMJ cartilage.
Results:  The number of apoptotic cells increased in all experimental animals. More apoptotic cells were observed in the articular eminences than in the condyles. The type 2 collagen-positive area in the condyles was reduced at the beginning but recovered within 4 weeks, and remained small throughout this experimental period in the articular eminences.
Conclusions:  These findings suggest that histopathological changes occurred in response to alteration of the occlusal plane. The influence decreased as the occlusal plane recovered in the condyles, but the immunocytochemical and immunohistochemical influence continued in the articular eminences.     

正常(牙合)牙尖交错位咬合平衡的定量研究

目的　对正常（牙合）牙尖交错位（ICP）最大（牙合）力咬合进行定量研究，初步探讨ICP咬合平衡的生理范围。方法　应用T－Scan　Ⅱ系统记录123名正常骀者ICP最大（牙合）力的咬合情况，测量并计算力的中心点（COF）、（牙合）力百分比值、胎接触点数目。结果　正常胎者ICP最大（牙合）力时力的中心点相对位置、（牙合）力百分比差值以及不对称系数均服从正态分布，95％参考值范围分别为：－6．60～6．68mm，－15．50％～12．10％，0．65～1．39；98．4％的正常（牙合）者ICP最大（牙合）力咬合时力的中心点分布于后牙区。结论　正常（牙合）者最大（牙合）力时ICP咬合是稳定、平衡的咬合。