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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.     

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。     

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.     

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.     

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??Objective    To investigate the relationship between the depth of curve of Spee??COS?? and temporomandibular joint disorders??TMD?? in elderly patients. Methods    Eighty-nine elderly patients with TMD visiting the Hospital of Stomatology of China Medical University from January 2013 to June 2013 were recruited in the study by random number table. Muscle pain and temporomandibular joint??TMJ??sounds were examined according to Research Diagnostic Criteria for TMD??and the depth of COS were measured on the dental casts. The mean depth of COS of patients without muscle pain and patients with pain at all levels were compared??and the unilateral depth of COS of patients with and without TMJ sounds were compared. Related data were analyzed statistically with one-way analysis of variance and t-test. Results           The depth of ipsilateral COS of patients with TMJ sounds was significantly smaller than those of patients without TMJ sounds??left??P < 0.001??right??P = 0.008????while the depth of contralateral COS of patients with TMJ sounds had no significant differences with those of patients without TMJ sounds??left??P = 0.481??right??P = 0.905??. In addition??there were no significant differences between the mean depth of COS of patients without muscle pain and patients with pain at all levels??P = 0.327??. Conclusion    TMJ sounds are closely associated with COS??and the depth of ipsilateral COS of patients with TMJ sounds is smaller??and the COS is flatter. There is no significant association between the mean depth of COS and muscle pain.     

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.     

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.     

Signs and symptoms of temporomandibular disorders in Nigerian adult patients with and without occlusal tooth wear

OBJECTIVES: The purpose of this study was to investigate the prevalence of signs and symptoms of temporomandibular disorders in Nigerian patients with and without occlusal tooth wear, and to relate the signs and symptoms with the severity of occlusal tooth wear. METHODS: One hundred and fifty patients with occlusal tooth wear, and 100 control subjects participated in this study (mean age 40.8 +/- 12.2 years, range 18-65 years). Exclusion criteria included patients and subjects with more than one missing opposing pair of premolars or molars, restorations covering the entire incisal edge, canine cusps and occlusal surfaces of premolars and molars. The severity of occlusal wear was assessed using the tooth wear index (TWI) designed by Smith and Knight (1984). Chi-square test was used to compare the differences in signs and symptoms of TMD. P < 0.05 was defined as significant. RESULTS: Although more females reported pain than males the difference was not statistically significant (p = 0.05). Except for impaired range of movement, tooth wear patients and controls differ significantly with respect to the variables; pain report, pain on palpation, TMJ sound and deviation on opening (p < 0.001). Patients with mean occlusal TWI score of > or =3 differ significantly from those with TWI score < or =2 with respect to pain on palpation and TMJ sound (p < 0.001). CONCLUSIONS: Posterior occlusal wear (mean TWI scores of 3 or 4) was significantly associated with pain on palpation and TMJ sound. Hence there may be a clinically relevant risk of TMD among Nigerian patients with occlusal tooth wear.     

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.     

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.     

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.     

Analysis of the condyle/fossa relationship before and after prosthetic rehabilitation with maxillary complete denture and mandibular removable partial denture

STATEMENT OF PROBLEM: The influence of the loss of posterior teeth on the condylar position and on temporomandibular disorders (TMDs) remains a controversial issue. PURPOSE: This study investigated whether prosthetic rehabilitation promoted modification of the condylar position in subjects without symptoms of TMDs. MATERIAL AND METHODS: The temporomandibular joints (TMJs) of 12 women (age 37 to 74), all with existing maxillary complete dentures but no removable partial denture (RPD) restoring the Kennedy class I partially edentulous mandibular arch and no clinical signs of TMDs according to the criteria established by Helkimo, were viewed in maximal intercuspal position with corrected lateral tomography before and after prosthetic rehabilitation with a new maxillary complete denture and a mandibular RPD. Before prosthetic rehabilitation, a mandibular stabilizing base was fabricated to prevent the existing maxillary complete denture from dislodging during tomographic examination. Two methods were used to evaluate tomograms: (1) linear measurements of the subjective narrowest anterior and posterior intra-articular joint spaces made from the tomograms by use of a digital caliper and (2) linear measurements of the anterior and posterior intra-articular joint spaces on the basis of drawings and tracings. Repeated-measures analysis of variance followed by orthogonal contrasts were used to evaluate differences between measurements carried out on the same subject under the different test conditions of the study (before prosthetic rehabilitation, before prosthetic rehabilitation with a mandibular stabilizing base in position, and after prosthetic rehabilitation) (P<.05). RESULTS: Before prosthetic rehabilitation, a predominance of posterior condylar positions was observed. Before prosthetic rehabilitation with a mandibular stabilizing base in position, a significant decrease was observed in posterior condylar positions (P=.03). This decrease was more marked after prosthetic rehabilitation (P=.02). The subjective evaluation and comparison on the basis of drawings and tracings used to analyze the tomograms produced similar results (P=.70). CONCLUSION: Within the limitations of this study, significant changes in the condylar position occurred after prosthetic rehabilitation in subjects without symptoms of TMDs.     

Signs and symptoms associated with TMD in adults with shortened dental arches

PURPOSE: This study investigated the prevalence of signs and symptoms associated with temporomandibular disorders (TMD) in adults with shortened dental arches in Tanzania. MATERIALS AND METHODS: The shortened dental arch group comprised 725 subjects with an intact anterior region and zero to eight occluding pairs of teeth posteriorly. They were categorized into five groups according to length and symmetry of the dental arches. A control group of 125 subjects with complete dental arches was included. The subjects were interviewed with questions related to pain and sounds within the temporomandibular joints and restricted mobility of the mandible. Clinical examination consisted of registration of clicking or crepitation of the joints, measuring maximum mouth opening, and assessing occlusal tooth wear. RESULTS: Joint sounds were reported significantly more frequently by subjects with posterior support only unilaterally (17%) and by subjects with no posterior support (10%) compared to other categories of dental arches (3% to 5%). No significant differences were found between categories of dental arches with respect to pain (2% to 9%), restricted mobility of the mandible (0% to 1%), maximum mouth opening < 40 mm (0% to 3%), or clicking or crepitation of the joints (12% to 23%). For the younger age group (> or = 20 and < 40 years), tooth wear occurred significantly more often in subjects with no posterior support. For the older age group (> or = 40 years), tooth wear increased significantly with decrease of posterior support. CONCLUSION: No evidence was found that shortened dental arches provoke signs and symptoms associated with TMD. However, when all posterior support is unilaterally or bilaterally absent, the risk for pain and joint sounds seems to increase.     

Anamnestic Index Severity and Signs and Symptoms of TMD

Abstract

The aim of this study was to determine the frequency and to characterize the symptoms and clinical signs of temporomandibular disorders (TMD) related to each severity category of Fonseca’s anamnestic index in a sample of Brazilian young adults (mean age 21.61±1.91 years, 87% females and 13% males), by the application of an anamnestic index proposed by Fonseca (1992) and by clinical examination considering mandibular range of motion and tenderness to palpation of stomatognathic system structures. A significant number of participants were classified with mild TMD (43.2%) and moderate TMD (34.8%). Pain frequency during mastication, temporomandibular joint (TMJ) pain, and TMJ sounds were shown to be good predictors of TMD severity. Neck pain, headache, difficulty during mouth opening and lateral deviation, and tenderness to palpation of masticatory sites and during protrusion accompanied the TMD severity but failed to demonstrate differences between moderate and severe groups, showing a poor ability to determine TMD severity progression. This study suggests that not only the frequency of signs and symptoms of TMD should be determined, but also symptom severity and its relationship to the presence of clinical signs in order to discriminate patients with real treatment needs in nonpatient samples.     

Association between posterior crossbite and/or deep bite and temporomandibular disorders among Palestinian adolescents: A sex comparison

ABSTRACT

Objective: To assess the prevalence of temporomandibular disorders (TMDs) and posterior crossbite and/or deep bite and any possible association between them.

Methods: One thousand-nineteen adolescents responded to a questionnaire regarding oral habits and TMD symptoms. Afterwards, they were diagnosed according to the Axis I of the DC/TMD and underwent a dental examination. The chi-square test was used for statistical analysis.

Results: A significant association was found between posterior crossbite and some TMD diagnosis, but no association was found between deep bite and TMD, nor between occlusal diagnosis and bruxism. TMDs were more prevalent in girls. There was a significant sex difference (more among females) in the prevalence of painful TMDs.

Conclusion: Posterior crossbite in the adolescent population analyzed may be related to TMDs, in contrary to deep-bite. The presence of posterior crossbite may have different impact on TMD findings between the sexes.     

Temporomandibular disorders in the active phase of orthodontic treatment

summary Subjective symptoms and clinical signs of temporomandibular disorders (TMD) as well as presence of headache, bruxism and occlusal interferences were examined in 50 patients (mean age 12.9 years) before, during and immediately after orthodontic treatment. The prevalences of signs and symptoms of TMD were high before the treatment in comparison with subjects in an epidemiological study. Except for TMJ sounds, signs and symptoms of TMD as well as presence of headache decreased during the treatment. The major factor for decrease of the dysfunction index during the treatment compared with before the treatment, was tenderness to palpation of the masticatory muscles. Although there was a high prevalence of occlusal interferences during treatment, they seemed to have little importance for development of TMD. One explanation may be that the orthodontically moved teeth are sensitive to contact resulting in a decrease of oral parafunctions. Such a decrease was also reported by the patients.     

Functional Disturbances of the Masticatory System and the Effect of Prosthetic Treatment in Patients Treated with Fixed Prosthesis Four Years Earlier

Dysfunction of the temporomandibular joint has been studied in many epidemiological and follow-up studies, and it has been shown that temporomandibular joint dysfunction is a common complaint. This article describes the frequency of signs and symptoms of dysfunction of masticatory system four years after the treatment with fixed prosthesis. In addition, the effect of preprosthetic treatment has been related to the frequency of occlusal disturbances. The study consists of 147 subjects treated with fixed prosthesis whowere divided into two groups according to the preprosthetic treatment. Anamnestic symptoms and clinical signs were recorded more frequently in the group without any preprosthetic treatment than in the group with preprosthetictreatment. A statistically significant difference was found in the occlusal index (O_iII) between pretreated and untreated patients. Thus, an improvement in the occlusal state was detected in subjects due to the treatment, although the occlusal grinding could not directly effect a single sign or symptom of dysfunction. The most common signs and symptoms were temporomandibular joint sounds in 45% and 54%, pain of muscle in 34% and 24% and mandibular deflection of opening in 60% and 54% of the untreated and pretreated patients, respectively.     

Prevalence of signs and symptoms of temporomandibular disorders in an urban and rural German population: results of a population-based Study of Health in Pomerania.

OBJECTIVE: Based on a randomized, population study (Study of Health in Pomerania [SHIP]), the objective of the present study was to determine incidence of signs and symptoms of temporomandibular disorders (TMD) in adults 20 years or older and to compare the data with TMD prevalence of other exclusively random sample studies that fulfilled criteria similar to those of this study (age > or = 20 years, age range > or = 40 years, sample size > or = 500 subjects, equal gender distribution). METHOD AND MATERIALS: Men and women (n = 7,008) 20 to 79 years of age from mid- and small-sized towns in a rural region in northeast Germany were randomly sampled from resident registry office files. The response rate was 68.8%. Adults between the ages of 20 and 81 years (n = 4,289) were clinically and anamnestically examined. RESULTS: Half of the subjects (49.9%) had one or more clinical signs of TMD, but only 2.7% were subjectively aware of temporomandibular joint (TMJ) pain symptoms. Women showed higher frequency for all signs and symptoms of TMD than men. However, these differences were not significant for all signs and symptoms in all age groups. The influence of age on TMD signs and symptoms was less pronounced. The prevalence for the following variables found in the present study compared to those of other comparable, random sample studies was: clinical examination; (TMJ) tenderness to palpation (5% versus 2% to 6%); masticatory muscle tenderness (15% versus 19% to 21%); joint sounds (25% versus 15% to 25%); limited maximum mouth opening < 40 mm (9% versus 5% to 8%); pain upon movement of the mandible (1% versus 1% to 3%); irregular jaw movements (deviation, deflection) (28% versus 28%); interview: subjective joint sounds (9% versus 11% to 13%); and subjective TMJ pain (3% versus 4% to 7%). CONCLUSION: The TMD incidence in the current study agreed quite well with the other studies based on random samples with similar subjects and design. The large range of prevalence for signs and symptoms of TMD documented in reviews and meta-analyses could therefore not be confirmed.     

The treatment of painful temporomandibular joint clicking with oral splints: a randomized clinical trial

BACKGROUND: The authors compared the efficacy of bilateral balanced and canine guidance (occlusal) splints in the treatment of temporomandibular joint (TMJ) pain in subjects who experienced joint clicking with a nonoccluding splint in a double-blind, controlled randomized clinical trial. METHODS: The authors randomly assigned 57 people with signs of disk displacement and TMJ pain into three groups according to the type of splint: bilateral balanced, canine guidance and nonoccluding. The authors followed the groups for six months using analysis of a visual analog scale (VAS), palpation of the TMJ and masticatory muscles, mandibular movements and joint sounds. They used repeated analysis of variance and a chi(2) test to test the hypothesis. RESULTS: The type of guidance used did not influence the pain reduction, yet both occlusal splints were superior to the nonoccluding splint, on the basis of the VAS. Despite similar outcomes in relation to opening, left lateral and protrusive movements, TMJ and muscle pain on palpation, subjects who used the occlusal splints had improved clinical outcomes. The frequency of joint noises decreased over time, with no significant differences among groups. Subjects in the groups using the occlusal splints reported more comfort. CONCLUSION: The type of lateral guidance did not influence the subjects' improvement. All of the subjects had a general improvement on the VAS, though subjects in the occlusal splint groups had better results that did subjects in the nonoccluding splint group.     

Patterns of cervical and masticatory impairment in subgroups of people with temporomandibular disorders–an explorative approach based on factor analysis

Objectives: To identify clinical patterns of impairment affecting the cervical spine and masticatory systems in different subcategories of temporomandibular disorder (TMD) by an explorative data-driven approach.

Methods: For this observational study, 144 subjects were subdivided according to Research Diagnostic Criteria for TMDs into: Healthy controls, temporomandibular joint (TMJ) signs without symptoms, TMJ affected, temporomandibular muscles affected, or TMJ and muscles affected. Factor analysis and linear regression were applied to cervical spine and masticatory data to identify and characterize clinical patterns in subgroups.

Results: Factor analysis identified five clinical dimensions, which explained 59% of all variance: Mechanosensitivity, cervical movement, cervical and masticatory dysfunction, jaw movement, and upper cervical movement. Regression analysis identified different clinical dimensions in each TMD subgroup.

Conclusion: Distinct clinical patterns of cervical spine and masticatory function were found among subgroups of TMD, which has clinical implications for therapeutic management.