Joint vibrations analysis in asymptomatic volunteers and symptomatic patients

Condyle bone destruction: the association between temporomandibular joint vibration and finite element analysis

OBJECTIVE

The objective of the study is to investigate the stress distributions of condyle and articular disc at different mandibular plane angles and the association between the temporomandibular joint (TMJ) vibration and anatomical relationship.

SETTING AND SAMPLE POPULATION

Data from 195 untreated patients were analyzed. Patients were, respectively, divided into 3 groups, based on cone-beam computed tomography (CBCT): Group 0 presenting normal condyles, Group 1 presenting mild bone change, and Group 2 presenting severe bone change; based on magnetic resonance imaging (MRI): normal disc position (N), disc displacement with reduction (DDR) and disc displacement without reduction (DDNR); based on the mandibular plane angle: low, normal and high.

METHODS

(1) According to peak frequency, average amplitude, and occurrence phase, association was assessed between TMJ condition and TMJ vibration; (2) A three-dimensional finite element model of masticatory system was established and the relationship between mandibular plane angle and condyle bone destruction was described.

RESULTS

The average amplitude of TMJ vibration negatively correlated with pathological condition of the articular disc (p < 0.01). The angle of SN-MP was strongly relevant to bone destruction of condyle (p < 0.01), and the biomechanical analysis showed that with the increase of SN-MP angle, the area of stress concentration in the posterior slope of condyle rose.

CONCLUSIONS

The average amplitude of TMJ vibration decreased with the pathological position state of articular disc, and condyle bone destruction was positively associated with SN-MP angle.

Relationship between emotional state and masticatory system function in a group of healthy volunteers aged 18-21

OBJECTIVE

To determine the role of emotional state in the masticatory system function in a group of young adults.

METHODS

Ninety-six generally healthy randomly selected students aged 18-21 were examined. They were subjected to a questionnaire survey determining their emotional state, clinical examination, and instrumental diagnostics (EMG, Cadiax Compact, JVA).

RESULTS

The stress symptoms group revealed a greater intensity of neck and shoulder muscles pain (p < 0.05) and an increase of electrical potential of the masseter muscles in maximal voluntary clench (p < 0.05). They reported more often headache (p < 0.001), tension/contracture of the head, neck and nape (p < 0.05), and pain while opening the mouth wide (p < 0.05). The values of parameters obtained in the instrumental diagnostics did not reveal differences between the groups.

CONCLUSION

Stressful situations increase muscular tension but do not have a direct impact on the temporomandibular joints function.

Assessment of the Temporomandibular Joint Function in Young Adults without Complaints from the Masticatory System

Objective of the study was to evaluate the clinical status of the masticatory system in young adults with full permanent dentition and no stomatognathic system complaints. The study involved 186 randomly selected people with full dental arches with normal occlusal conditions corresponding to Angle's Class I aged 18 - 21 years with an average age of 19 years. Subjects were clinically examined and temporomandibular joint (TMJ) vibrations were recorded during open-wide and close movements using BioJVA. Then, patients were categorized into groups according to Piper's classification system. The TMJs of the subjects were categorized according to the values of the vibration energy and the Piper protocol. This detected 33.4% of the joints with loosened ligaments, subluxation in 8.28%, initial signs of disc dysfunction in 5.08% and disc displacement without locking in 1.6 %. Median frequency differed significantly (p < 0.05) between the group of subjects with initial signs of TMJ dysfunction and other groups. Peak Frequency differed significantly (p < 0.05) between the healthy joints and those with TMJ subluxation. In this group of young healthy people, the majority of study joints generated small vibrations. However, a subset of people manifested higher vibrations that may indicate an early stage of TMJ dysfunction. Median Frequency was an important parameter for detecting initial symptoms of TMJ dysfunction. Peak Frequency was an important characteristic parameter for detecting TMJ subluxation.

Is There an Association Between Temporomandibular Joint Effusion and Arthralgia?

PURPOSE

The literature on joint effusion (JE) and its association with clinical and radiologic variables in patients with temporomandibular disorders (TMDs) is inconsistent and is characterized by multiple methodologic limitations. The primary aim of this investigation was to evaluate the association between magnetic resonance imaging (MRI) identified JE and temporomandibular joint (TMJ) arthralgia. The secondary aim of this investigation was to determine the association between JE and other clinical and MRI-identified soft tissue characteristics.

MATERIALS AND METHODS

A retrospective cohort study was conducted. Clinical and soft tissue imaging assessments were carried out according to the Diagnostic Criteria for Temporomandibular Disorders guidelines. The dependent variable was JE and the primary independent variable was arthralgia. The secondary independent variables were TMJ pain-associated characteristics and MRI-identified variables. When applicable, Pearson χ² or t test was used to determine the statistical associations between JE and clinical characteristics and between JE and MRI-identified variables. Furthermore, generalized estimating equation (GEE) modeling was conducted to determine which of the independent clinical and MRI-identified variables were associated with JE.

RESULTS

Data for 158 participants, representing 312 joints, were extracted. The mean age of the female sample (59.4%) was 31 ± 11.1 years and that of the male sample (40.6%) was 29.8 ± 9.7 years. No association was found between JE and arthralgia. However, statistically significant associations were found between JE and lateral disc rotation (P = .001) and between JE and disc position in the coronal and sagittal planes (P = .001). The GEE model suggested that disc displacement with reduction (odds ratio = 2.5) was a statistically relevant contributing factor for JE in the absence of degenerative joint disease.

CONCLUSION

Results associated JE with the position of the disc in the sagittal plane. No association was found between JE and arthralgia or TMJ pain-associated clinical characteristics in patients with TMDs.

Temporomandibular joint vibrations from totally asymptomatic subjects

OBJECTIVE

Precisely characterize the TMJ vibrations of a youthful, adult and completely asymptomatic population.

METHODS

TMJ vibrations were recorded from 237 asymptomatic subjects (163 f, 74 m) at Dayananda Sagar Institute in India. The subjects were selected, examined and informed (WMA Helsinki Declaration). TMJ vibrations were recorded bilaterally during maximal open - close. 6 parameters of the vibrations were analyzed between the left and right sides, between genders and with respect to age.

RESULTS

Mean vibration intensity was greater for females (p < 0.01) than males. A portion of the frequency spectrum < 300 Hz was also more intense for females (p < 0.022). Females 18 - 20 years old exhibited higher Peak Amplitude than 27 - 30 year olds (p < 0.025) and lower Median Frequency (p < 0.005).

CONCLUSIONS

A significant difference in TMJ vibrations was present between males and females, increased with age in females but not in males.

Analysis of TMJ vibration sounds before and after use of two types of occlusal splints

Temporomandibular joint (TMJ) sounds are important and common physical signs of temporomandibular disorders (TMD). The aim of this study was to evaluate the influence of the effect of the use of occlusal bite splints (stabilizing and repositioning) on the sounds produced in the TMJ, by means of the electrovibratography (EVG). Thirty-one patients with TMD from the Dental School of Ribeirão Preto, University of São Paulo, Brazil were selected for this study. Group 1 (n=23) wore stabilizing bite splints and Group 2 (n=8) used anterior repositioning splints. Before and after treatment with occlusal splints both groups were analyzed using the SonoPAK Q/S recording system (BioResearch System, Inc.). The treatments with stabilizing bite splints were satisfactory, since they reduced the total amount of the sound energies (p<0.05), but the use of anterior repositioning splints for no more than 4 weeks produced significantly better results (p<0.01). The total amount of vibration energy involved in the vibrating movements of the TMJ showed significant improvement using anterior repositioning splints.

The dynamic range of TMJ sounds

It is of clinical interest to record the amplitudes of temporomandibular joint (TMJ) sounds. The aim was to test the hypothesis that sealing the meatus, when placing a microphone in the ear canal affects such recording by increasing the sound pressure level (SPL). Bilateral recordings of 249 TMJ clickings were made from three subjects, using sampling rates of 48 or 96 kHz and 24 bits A/D conversion, with and without the ear canals sealed by Silicone putty. The peak-to-peak equivalent sound pressure level (peSPL) was higher (P < 0.001) when the ear canal was sealed (range of mean differences was 8.3-24.9 dB peSPL). This means that the signal to noise ratio can be improved by sealing the meatus because the electronic noise level is not increased. Most important is that the dynamic range of the clicking sounds was 62 dB that is larger than the effective dynamic range of a 16 bits sound card. Future studies are needed to establish normative peSPL values. However, cards with at least 24 bits A/D conversion will be required, especially in patients with suspected disc displacement with reduction, where the difference in loudness between opening and closing clicking often is large.

Chiropractic care of a patient with temporomandibular disorder and atlas subluxation

OBJECTIVE

To describe the chiropractic care of a patient with cervical subluxation and complaints associated with temporomandibular disorder.

CLINICAL FEATURES

A 41-year-old woman had bilateral ear pain, tinnitus, vertigo, altered or decreased hearing acuity, and headaches. She had a history of ear infections, which had been treated with prescription antibiotics. Her complaints were attributed to a diagnosis of temporomandibular joint syndrome and had been treated unsuccessfully by a medical doctor and dentist.

INTERVENTION AND OUTCOME

High-velocity, low-amplitude adjustments (ie, Gonstead technique) were applied to findings of atlas subluxation. The patient's symptoms improved and eventually resolved after 9 visits.

CONCLUSION

The chiropractic care of a patient with temporomandibular disorder, headaches, and subluxation is described. Clinical issues relevant to the care of patients with this disorder are also discussed.