Relationship among Cervical Spine Degeneration, Head and Neck postures, and Myofascial Pain in Masticatory and Cervical Muscles in Elderly with Temporomandibular Disorder

Measurement proprieties of the CROM instrument for assessing head posture, neck retraction and protraction

BACKGROUND

The CROM instrument is widely used clinically and in research to measure neck range of motion. However, its measurement proprieties during the assessment of protraction and retraction movements were not examined so far.

OBJECTIVE

To analyse the intra- and inter-rater reliability, the concurrent validity of the CROM for measuring head posture, retraction and protraction in healthy subjects.

METHODS

Thirty-three asymptomatic subjects were recruited and assigned in a random order to one of two raters. After a 10-min break, they were examined by a second rater (Assessment 1). After a 30-min break, both raters repeated the examination (Assessment 2). The examination consisted of measuring the head posture, maximum head protraction and maximum retraction. Each movement was repeated 3 times and measured simultaneously with the CROM and with a 3D capture system laboratory.

RESULTS

The intra-rater reliability of the CROM was excellent for both raters for head posture and all head movements (ICC>0.9, 95% CI: 0.82-0.99, p < 0.01). The inter-rater reliability was excellent for head posture (ICC>0.95, 95% CI: 0.92-0.98, p < 0.01) and good-to-excellent for all movements at both time-points (ICC = 0.73-0.98, 95%CI: 0.45-0.99, p < 0.01). The validity analysis showed moderate-to-strong correlation between instruments for the head posture and head movements [(r) = -0.47 to -0.78), 95% CI: 0.99 to -0.24, p < 0.01].

CONCLUSION

The CROM instrument has good-to-excellent reliability and adequate validity for measuring cervical position and displacement in the sagittal plane.

Effects of sustained natural apophyseal glides versus rocabado 6 × 6 program in subjects with cervicogenic headache

BACKGROUND

Cervicogenic headache is designated as the most common type of secondary headache that results from conditions affecting the neck's bony components, muscles, and intervertebral discs rather than the head itself.

OBJECTIVE

The purpose was to determine the effects of Sustained Natural Apophyseal Glides (SNAGs) versus the Rocabado 6 × 6 program in subjects with cervicogenic headaches.

METHODS

This study was a randomized clinical trial. The sample size was 38, and participants aged 20-60 years (mean age 40.22 ± 9.66) suffering from cervicogenic headaches were randomly allocated using the lottery method into two groups with 19 participants in each group. Assessment of subjects was done before starting treatment and by the end of the 8th week for all the variables. Outcome measures were the Neck Disability Index (NDI), 6-item Headache Impact Test (HIT-6), Flexion-Rotation test (FRT) to assess the rotation range of motion at the level of C1-C2 (goniometer) and the Numeric Pain Rating Scale (NPRS) for the intensity of pain. Data analysis was done by SPSS (IBM) 25. To check the normality of the data the Shapiro-Wilk test was used.

RESULTS

In the Shapiro-Wilk test p-value of all the testing variables i.e. NDI, HIT-6 score, FRT and NPRS was > 0.05, data was normally distributed and parametric tests were used. Group A showed a considerable improvement (p < 0.05) in all variables compared to Group B, while within-group analysis of both groups shows that all outcome measures show significant results (p < 0.05).

CONCLUSION

It was concluded that both SNAGs and Rocabado's 6 × 6 exercises were effective for the treatment of cervicogenic headache but the effects of headache SNAG were superior and produced more improvement in intensity of headache, disability, frequency of headache, duration of headache as compared to Rocabado 6 × 6 exercises.

TRIAL REGISTRATION NUMBER

This study was registered at ClinicalTrials.gov ID: NCT05865808 on date 19/05/2023.

Relationship Between Occlusal Factors and Temporomandibular Disorders: A Systematic Literature Review

Temporomandibular disorders (TMD) originate from various components within the temporomandibular joint (TMJ), causing an impact on the masticatory muscles, the joint itself, and associated structures. They are a widely prevalent issue across the world. According to epidemiological research, up to 50% of adults in the population have TMD-related symptoms. The objective of this work was to analyze the existing scientific literature regarding the association between malocclusion classes, bruxism, and tooth loss in relation to the etiology of TMD. This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 analysis protocol. For the development of the question focus, the population, intervention, control, and outcomes (PICO) study design protocol was used. The question in focus according to the PICO format was: "Do malocclusion, tooth loss, and bruxism contribute to temporomandibular disorders?". The review was performed with articles from PubMed, Web of Science, and Google Scholar databases according to the specified inclusion and exclusion criteria. The included articles were not older than five years. The risk of bias was assessed in the included studies by using the Cochrane Risk-of-bias 2 (RoB-2) tool. Out of a total of 32 results received, 21 articles were chosen according to the established criteria after conducting a review and analysis of their full texts. The article search sequence was presented in the PRISMA 2020 flow diagram, and the outcomes of the chosen articles were presented. The literature results revealed a relationship between occlusion and the development of TMD. The influence of occlusal factors on the TMJ was explained by an examination of joint anatomy and symptoms related to TMD. This study revealed variations in TMJ factors across different malocclusion classes. Additionally, it was observed that the occurrence and attributes of TMD are influenced by the number of tooth loss quadrants and the frequency of missing teeth. Furthermore, a correlation was found between bruxism and the symptoms of TMD, including myofascial pain, disc displacement, arthralgia, and muscle disorders. This literature review provides comprehensive information on the relationship between malocclusion classes, bruxism, tooth loss, and TMDs. This prompts healthcare professionals to prioritize patients' occlusal assessment and TMJ condition.

[Effect of the forward head syndrome in the development of temporomandibular disorders]

Bad habits, such as poor posture during the use of technological devices, poor abdominal control and oral breathing pattern can lead to a forward head position, which has important implications for the entire future of the individual, especially at the stomatognathic system. There is a strong association between temporomandibular disorders and forward head syndrome. Where the muscular component is the main affected, with the appearance of more trigger points at the level of the sternocleidomastoid muscles, upper trapezius, rectus capitis posterior and upper oblique capitis. Degenerative changes in the temporomandibular joint have been observed, but evidence is still lacking to ensure that Forward Head Syndrome is the etiological factor.

Cervical Range of Motion Analysis Performed with an Accelerometer: A Study of Intersession Reliability for Dental Practice

During the clinical examination of subjects with temporomandibular disorders (TMDs), the dentist sometimes must evaluate the cervical spine, due to the anatomical and functional connections between the cervical portion of the spine and the stomatognathic apparatus. The accelerometer is a device that evaluates the Range of Motion (ROM) of the main movements of the head on the neck. To date, only a few studies have investigated the repeatability of the use of the accelerometer in the assessment of cervical ROM. Therefore, the present longitudinal observational study analyzed the repeatability of acquired cervical movements on a sample of volunteer subjects who underwent accelerometer testing. A sample of 32 subjects was tested twice within 14 days to assess cervical ROM using a standardized protocol based on a review of existing literature. The results show that the examination is reliable for all the positions of the jaw, except for the parameters regarding the asymmetries of rotation and bending. In conclusion, the accelerometer can be considered a reliable tool for evaluating the active cervical ROM. However, further studies will be necessary to make better evaluations.

Myofascial Pain as an Unseen Comorbidity in Osteoarthritis: A Scoping Review

OBJECTIVE

This review aimed to identify, summarize, and appraise the evidence supporting the coexistence of myofascial pain (MPS) and trigger points (MTrP) in osteoarthritis (OA), and the effectiveness of MTrPs treatments in OA-related pain and physical function outcomes.

METHODS

Three databases were searched from inception to June 2022. We included observational and experimental studies to fulfill our 2 study aims. Two independent reviewers conducted 2-phase screening procedures and risk of bias using checklist tools for cross-sectional, quasi-experimental, and randomized control trials. Patient characteristics, findings of active and latent MTrPs in relevant muscles, treatments, and pain and physical function outcomes were extracted from low-risk bias studies.

RESULTS

The literature search yielded 2898 articles, of which 6 observational and 7 experimental studies had a low bias risk and the data extracted. Active MTrPs in knee OA patients was more evident in the quadriceps and hamstring muscles than in healthy individuals. Dry needling on active MTrPs improved pain and physical function in the short term compared with sham treatment in hip OA patients. In knee OA, dry needling on latent or active MTrPs improved pain and functional outcomes compared with sham needling but did not result in better pain and physical outcomes when combined with a physical exercise program.

DISCUSSION

The presence of active versus latent MTrPs seems to be a more sensitive discriminating feature of OA given that latent is often present in OA and healthy individuals. Dry needling on active MTrPs improved pain and physical function in the short term compared with sham treatment in hip OA patients. However, the small sample size and the few number of studies limit any firm recommendation on the treatment.

REGISTRY

The study protocol was prospectively registered in Open Science Framework (https://doi.org/10.17605/OSF.IO/8DVU3).

Temporomandibular disorders and neck pain in primary headache patients: a retrospective machine learning study

OBJECTIVES

To evaluate the linkage underpinning different clinical conditions as painful TMD and neck pain in patients affected by primary headaches.

MATERIALS AND METHODS

In this machine learning study, data from medical records of patients with headaches as migraine, tension-type headache (TTH) and other primary ones, referring to a University Hospital over a 10-year period were analysed. VAS was used to evaluate the intensity of the TMD and neck pain. Moreover, the magnetic resonance imaging was used to supplement the clinical data.

RESULTS

A total of 300 patients (72 male, 228 female), mean aged 37.78 ± 5.11 years, were included. Higher TMD and neck pain VAS in migraine patients were reported. The machine learning analysis focussed on type of primary headache demonstrated that a higher TMD VAS was correlated to migraine, whereas a higher neck pain VAS was correlated to TTH or migraine. Concerning the TMD type, arthrogenous and mixed TMD were correlated to mild-moderate TMD pain (depending on neck pain intensity), whereas myogenic TMD was correlated to moderate-severe TMD pain.

CONCLUSIONS

Machine-learning approach highlighted the complexity of diagnosis process and demonstrated that neck pain might be an influential variable on the belonging to different group of headaches in TMD patients.

Do Temporomandibular Disorder Patients with Joint Pain Exhibit Forward Head Posture? A Cephalometric Study

Purpose

To evaluate head and cervical posture in individuals with or without temporomandibular disorders (TMDs) and to assess the correlations between pain, severity of symptoms, and posture.

Methods

A total of 384 patients (129 males and 255 females) was included. The Fonseca Anamnestic Index (FAI) was used to assess the severity and prevalence of TMD and the presence of temporomandibular joint (TMJ) pain. Patients were divided into three groups: the TMD-free group, TMD without TMJ pain group, and TMD with TMJ pain group. Subsequently, the patients with TMJ pain were further divided into mild TMD and moderate/severe TMD groups. Nine parameters were traced on cephalograms to characterize the head and cervical posture.

Results

TMD patients with TMJ pain showed increased forward head posture (FHP) than patients without TMJ pain and TMD-free subjects. No significant difference was observed between the TMD patients without TMJ pain and TMD-free subjects. In the TMD patients with the TMJ pain group, the moderate/severe TMD patients demonstrated increased FHP compared to mild TMD patients. TMD patients with joint pain had greater CVT/RL (B = 3.099), OPT/RL (B = 2.117), and NSL/C2' (B = 4.646) than the patients without joint pain after adjusting for confounding variables (P < 0.05).

Conclusion

TMD patients with TMJ pain showed increased FHP compared to other groups, and FHP became more significant as TMD severity increased in male patients, indicating the FHP might play an important role in the development of TMJ pain. In the clinical assessment of TMD, the patients' abnormal head and cervical posture might be considered.

The association between forward head posture and masticatory muscle pressure pain thresholds in patients with temporomandibular joint dissorders: a cross-sectional observational study

OBJECTIVES

Forward head posture (FHP) is common in patients with temporomandibular joint disorders (TMDs); however, whether it contributes to TMD symptoms remains unclear. The aim of this study was to investigate the association between (1) FHP and masticatory muscle pressure pain thresholds (PPTs) and (2) neck muscle and masticatory muscle PPTs.

MATERIALS AND METHODS

A total of 145 patients diagnosed with TMD were recruited between December 2020 and April 2021. Data regarding FHP and neck and masticatory muscle PPTs were collected. FHP was characterized by the craniocervical angle (CVA) measured between the horizontal line through C7 and the line between the tragus of the ear and C7. Patients were divided into either the FHP group (CVA ≤ 51°) or the non-FHP group. Differences in the masseter and temporalis muscle PPTs between the two groups were analyzed using the Mann-Whitney U test. The correlation between the CVA, neck, and masticatory muscle PPTs in all patients was determined by Spearman's correlation analysis.

RESULTS

There were 70 patients in the FHP group and 75 patients in the non-FHP group. No significant difference in masseter and temporalis muscle PPTs was found between the two groups (p > 0.05). No correlation was found between FHP and masticatory muscle PPTs (p > 0.05). A significant association was found between the neck muscle and masticatory muscle PPTs (p < 0.05). The C5-C6 pillar and masticatory PPTs were either moderately (r = 0.435, masseter muscle) or strongly (r = 0.608, temporalis muscle) correlated, while the correlation between the trapezius and masticatory muscles was moderate (r = 0.378, masseter muscle and r = 0.461, temporalis muscle).

CONCLUSION

FHP was not directly associated with masticatory muscle PPTs. Masticatory muscle PPTs were strongly or moderately associated with neck muscle PPTs. Therefore, the presence of neck pain, not the degree of FHP, in patients with TMD is of significance.

CLINICAL RELEVANCE

In TMD treatment, we should pay attention to and actively relieve neck pain.

Strength of scapular elevation in women with TMD and asymptomatic women

Temporomandibular disorder (TMD) is recognized for its high prevalence, presenting characteristic signs and symptoms. Cervical spine pain is present in 70% of diagnosed TMD cases. Aim: To verify if women with TMD present changes in isometric muscle strength in the scapula elevation. Methods: This is an observational, cross-sectional study. Thirty-five women, aged 22.89±2.04 years, were divided into the TMD group (TMDG), diagnosed with TMD according to the DC/TMD, and control group (CG), with asymptomatic individuals. The volunteers accessed a online link by the smartphone in order to answer questions on personal data, the Fonseca Anamnestic Index (FAI), Neck Disability Index (NDI), and Masticatory preference. In all participants, evaluation of the force of the scapula elevation muscles was performed, using a load cell model MM-100 (Kratos® SP, Brazil). Data were analyzed descriptively using the maximum, mean, and standard deviation and a two-way ANCOVA test was applied for all variables. A significance level of 5% was considered. Results: There were no statistically significant differences between the TMDG and CG for the maximal and mean muscle strength of scapular elevation. There were statistically significant differences in FAI (p <0.001*) between the CG and the TMDG. Conclusion: Based on the results, it was not possible to confirm the hypothesis that women diagnosed with TMD present lower isometric strength during scapular elevation (right/left).  

Effects of Occlusal Splints on Spinal Posture in Patients with Temporomandibular Disorders: A Systematic Review

There is still a gap in the scientific knowledge on the linkage between craniofacial structure and spinal postural control in temporomandibular disorder (TMD) patients. This systematic review aimed to assess the role of occlusal splints on spinal posture of TMD patients. PubMed, Web of Science, and Scopus were systematically searched from inception until 5 January 2022 to identify observational studies with a longitudinal study design presenting: patients with diagnosis of TMD according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD); occlusal splint therapy as intervention; postural assessment as outcome. Out of 133 records identified, 104 were suitable for data screening, and only 7 articles were included satisfying the eligibility criteria. We found that occlusal splints might have a positive effect on posture in TMD patients, albeit there is little evidence of appropriate investigation for postural assessment. This systematic review suggested that the occlusal splint might be considered a non-invasive therapeutic approach for patients with TMD. However, the low number of studies with high-quality methodology in these patients showed an urgent need for further research using combined force platform stabilometry and kinematic evaluation of the spine to investigate the impact of occlusal splints on posture.

Relationship between cervical angle and temporomandibular disorders in young and middle-aged population

OBJECTIVE

To verify temporomandibular disorders (TMDs) and cervical angles in a young and middle-aged population.

METHODS

Ninety participants were included, 45 of whom had TMDs. The participants were diagnosed according to the Research Diagnostic Criteria for TMDs. Lateral cervical radiographs were taken, and relevant cervical angles were measured. The general characteristics of the TMD group and control group were analyzed using chi-square analysis, and the relationship between cervical angles and TMDs was evaluated using the unpaired t-test.

RESULTS

The decrease in C2-C7 Cobb and increase in the posterior occipitocervical angle (POCA) were associated with the incidence of TMDs (p < 0.0001).

CONCLUSION

This study revealed that the cervical angle was related to TMDs. People with a long-time habit of head bending posture had a decrease in C2-C7 Cobb and an increase in the POCA. This group of people was more likely to develop TMDs.

Bone mineral density, cervical spine degeneration, head and neck posture, and neck pain in the post-menopausal females: A pilot study

The purpose of the present study was to reveal the relationship between degenerative changes in the cervical spine, head and neck postures, neck pain, and bone mineral density (BMD) of the total hip, femoral neck, and lumbar spine in post-menopausal females. In total, 116 females (mean age 60.4 ± 7.1 years; age range 50-80 years) were included. Participants were classified into three groups based on the T-score criteria of the total hip, femoral neck, and lumbar spine set by World Health Organization, respectively. The degree of neck pain was assessed using self-administered questionnaire, the Neck Disability Index. Cervical spine degeneration and head and neck postures were identified using the lateral cephalograms. Grading system for cervical degeneration included three categories of the radiographic alterations including disc height loss, osteophyte formation, and diffuse sclerosis. The areal BMD of the total hip, femoral neck, and lumbar spine were determined using dual-energy x-ray absorptiometry. Females with lower BMD exhibited lesser degree of neck pain and forward head posture (FHP) compared to those with normal BMD. Higher BMD seemed to be associated with more notable loss of the disc height at the level of C4-5. More prominent degenerative changes in the cervical spine were associated with higher areal BMD of the hip, femoral neck, and lumbar spine, altered head posture, and development of neck pain.

Orthodontic Treatment and Craniocervical Posture in Patients with Temporomandibular Disorders: An Observational Study

Orthodontic treatment acts through the application of forces and/or by stimulating and redirecting the functional forces within the craniofacial complex. Considering the interrelationship between craniomandibular and craniocervical systems, this intervention may alter craniocervical posture. Thus, our aim is to (a) compare craniocervical posture, hyoid bone position, and craniofacial morphology before, after, and also in the contention phase at least one year after the orthodontic treatment, in patients with temporomandibular disorders and (b) to verify whether the presence of condylar displacement, the skeletal class, or the facial biotype interferes with the abovementioned outcomes. To do so an observational, analytical, longitudinal, and retrospective design study was carried out. A non-probabilistic convenience sampling method was applied. The sample consisted of clinical records of patients diagnosed with temporomandibular disorders in order to compare pre-orthodontic treatment with post-orthodontic treatment (n = 42) and contention phase data (n = 26). A cephalometric analysis of several variables was performed. The p-value was set as 0.05. When the pre- and post-orthodontic treatment data were analyzed, there were statistically significant changes in variables concerning craniocervical posture (CV angle, C0-C1, and AA-PNS) and also concerning hyoid bone position (C3-Rgn). When pre- and post-orthodontic treatment and contention phase data were analyzed the variables concerning craniocervical posture (C0-C1, CVT/Ver, NSL/OPT, NSL/CVT, NSL/Ver; OPT/CVT, OPT/Ver) and facial biotype had statistically significant changes. This allowed us to conclude that in the sample studied, there were significant differences regarding hyoid bone position (pre- versus post-orthodontic treatment) and craniocervical posture (pre- versus post-orthodontic versus contention), with the craniocervical posture being prone to return to basal values. The presence of condylar displacement was found to significantly increase the H-H1 distance in the three moments of evaluation. Facial biotype was found to significantly increase the NSL/Ver angle on hypodivergent compared to hyperdivergent in the contention phase.

Neck associated factors related to migraine in adolescents with painful temporomandibular disorders

OBJECTIVE

Migraine is a comorbidity of painful temporomandibular disorders (TMDs). Both migraine and painful TMD have associations with neck pain and head posture. The aim of this study was to clarify the role of neck pain and head posture on the association between migraine and painful TMD in adolescents.

MATERIALS AND METHOD

In total 314 adolescents were included: 235 adolescents with only painful TMD (pTMD) and 79 adolescents with painful TMD and migraine (TMDMIG). Adolescents were diagnosed according to the Research Diagnostic Criteria for Temporomandibular Disorders and International Classification of Headache Disorders, 3rd edition. Head postures were identified using lateral cephalograms. Myofascial trigger points (TrPs) were evaluated in the temporalis, masseter, trapezius, sternocleidomastoid, sub-occipitalis, and splenius capitis muscles.

RESULTS

Multivariate logistic regression analysis confirmed the associations among the orofacial pain duration, number of active TrPs in the trapezius muscles, intensity of neck pain, and distance between the occiput and atlas and migraine in adolescents with TMD. The relationships among intensity of neck pain, number of TrPs in the cervical muscles, and head posture were more prominent in the TMDMIG than those in the pTMD.

CONCLUSION

Neck associated factors seemed to have relevance with migraine in adolescents with painful TMD.

Associations Among Temporomandibular Joint Osteoarthritis, Airway Dimensions, and Head and Neck Posture

PURPOSE

This study sought to investigate associations among progressive temporomandibular joint osteoarthritis (TMJ OA), airway dimensions, and head and neck posture.

MATERIALS AND METHODS

In total, 114 temporomandibular disorders (TMDs) patients were enrolled. Among 114 patients, 28 had no pathologic bony changes in the TMJ condyles (TMDnoOA), 45 had progressive TMJ OA (TMJOApro), and 41 demonstrated TMJ OA which had not progressed for 12 months (TMJOAnopro). TMJ OA was diagnosed based on the Diagnostic Criteria for TMD axis I. Computed tomography (CT) images and lateral cephalograms were obtained at baseline (T0) and 12 months after treatment (T1). The head and neck posture and airway area in upright position were analyzed using lateral cephalograms whereas airway volume in supine position was determined by 3D reconstructed CT images.

RESULTS

The volume change of the oropharynx in supine position was more prominent in the TMJOApro than in the TMDnoOA but no significant differences in changes in the pharyngeal airway while in upright position were detected. The retrognathic facial profile became more remarkable at T1 in the TMJOApro and TMJOAnopro compared to those at T0. The forward head posture seemed to be progressed in the TMJOApro than in either the TMJOAnopro or TMDnoOA.

CONCLUSION

Progressive TMJ OA may have associations with retrognathia and decreased oropharyngeal airway volume in the supine position but not in the upright position. Progressive TMJ OA may be related with altered head posture in the upright position to compensate for reduced airway dimensions.

Biomechanical musculoskeletal models of the cervical spine: A systematic literature review

BACKGROUND

As the work load has been shifting from heavy manufacturing to office work, neck disorders are increasing. However, most of the current cervical spine biomechanical models were created to simulate crash situations. Therefore, the biomechanics of cervical spine during daily living and occupational activities remain unknown. In this effort, cervical spine biomechanical models were systematically reviewed based upon different features including approach, biomechanical properties, and validation methods.

METHODS

The objective of this review was to systematically categorize cervical spine models and compare the underlying logic in order to identify voids in the literature.

FINDINGS

Twenty-two models met our selection criteria and revealed several trends: 1) The multi-body dynamics modeling approach, equipped for simulating impact situations were the most common technique; 2) Straight muscle lines of action, inverse dynamic/optimization muscle force calculation, Hill-type muscle model with only active component were typically used in the majority of neck models; and 3) Several models have attempted to validate their results by comparing their approach with previous studies, but mostly were unable to provide task-specific validation.

INTERPRETATION

EMG-driven dynamic model for simulating occupational activities, with accurate muscle geometry and force representation, and person- or task-specific validation of the model would be necessary to improve model fidelity.

Upper cervical spine abnormalities as a radiographic index in the diagnosis and treatment of temporomandibular disorders

OBJECTIVE

The aim of this study was to investigate the clinical characteristics and treatment outcomes of patients with temporomandibular disorders (TMD) according to the presence of upper cervical spine abnormalities and craniofacial morphology.

STUDY DESIGN

Clinical examinations were conducted on 43 patients with TMD. Upper cervical spine characteristics (fusion, posterior arch deficiency [PAD], and craniofacial morphology) reflecting head-and-neck posture were evaluated on lateral cephalograms. Condylar bone changes in the temporomandibular joint were evaluated by using cone beam computed tomography. Clinical characteristics and treatment outcomes after 1 year of conservative therapy were statistically analyzed between groups, according to the presence of upper cervical spine abnormalities.

RESULTS

Pain on neck muscle palpation was more frequent in patients with cervical fusion (P = .019) and with either fusion or PAD (P = .004) before treatment. Patients with PAD had smaller comfortable mouth opening ranges compared with those without the deficiency (P = .044) before treatment and smaller comfortable (P = .020) and maximum (P = .021) mouth opening ranges after treatment. Patients with PAD also had mouth opening limitation (P = .028) and pain on masticatory muscle palpation (P = .014) more frequently after treatment compared with patients without the deficiency.

CONCLUSIONS

Associations exist between upper cervical spine characteristics and treatment outcomes in patients with TMD, suggesting such parameters as a possible radiographic index in TMD diagnosis and treatment.