A Prospective Cohort Study of Diagnosed Meniere’s Disease / Tinnitus Cases, Evaluated with Digital Occlusion Analyzer and Treated with Disclusion Time Reduction Therapy

Introduction

There is ongoing debate in the health field about whether excessively unbalanced occlusal forces produced during mastication and other functions can induce hearing problems.¹ Costen in 1936 reported that loss of posterior teeth support would predispose subjects to shift the mandibular condyles posteriorly against the tympanum, resulting in compression of the eustachian tube, the auriculotemporal nerve, and/or the chorda tympani.^2,3 Thus the research question is, does unbalanced occlusal force induce ear symptoms?

Initially identified by Prosper Meniere, quite a few of publications on Meniere’s Disease (MD) are undertaken even today.⁴ However, diagnosis and treatment of MD still remains a challenge.^5-10 While endolymphatic hydrops (EH) is thought to play a role in causing MD, there is no consensus on this association.^9-16 Though attempts to induce MD by increasing endolymph production or restricting reabsorption were made, these models could not induce the symptoms.^17-19 Moreover, endolymphatic hydrops does not account for the persistence of ear fullness, tinnitus, or the progression of hearing loss.

Kerstein's study theorized that masticatory muscle hyperactivity during oral functions and parafunction due to prolonged mechanoreceptor compressions in the periodontal ligament (pdl) of posterior teeth may lead to signs and symptoms of temporomandibular dysfunction (TMD).²⁰ In the last 3-4 decades, the development of biometric tools for digital analysis of occlusal forces, electromyography of masticatory muscles, joint vibratography for temporomandibular joint study of mandibular movements using a kinesiograph helped to reveal the unknown terrain of Pitching/Roll/Yaw effects due to occlusal forces. TMD symptoms such as primary headaches, hearing loss, tinnitus, ear pain, pain around the eyeball, neck pain, and facial pain are the main symptoms.

This study illustrates patients diagnosed with Meniere's disease who also exhibited TMD symptomatology. Objective occlusal measurements performed with digital occlusal technology (T-Scan 10/BioEMG III; Tekscan, Inc., S.& Bioresearch Assoc., Milwaukee, WI, USA) revealed an imbalance of occlusal forces and the presence of prolonged exclusion time (DT) bilaterally. The patient chose to correct the underlying abnormalities of occlusal function, which significantly improved MD/ tinnitus symptoms, including the return of previous hearing loss, as verified by audiometric testing after occlusal treatment.

Objectives

This cohort study aims to treat patients with a confirmed diagnosis of tinnitus, who exhibited long excursion times and/or imbalance in bite force with high levels of excursive muscle activity, which may have contributed to MD symptoms/ tinnitus, with DTR therapy. Results of this work can either confirm or contradict previous work that observed a reduction in tinnitus/MD symptoms following measured occlusal adjustment.

Materials and Methods

Fifty patients assessed by an Otolaryngologist with Tinnitus/MD were examined in our dental practice, which renders DTR therapy for patients with temporomandibular dysfunction (TMD). MRI ruled out auditory neuromas. All these patients had undergone various treatments, including ear injections to dietary restrictions, but none provided any relief.

The dental practice was located at Raja Rajeshwari Dental College, Department of Orofacial Pain, in Bengaluru, India. The Otolaryngology Department of Raja Rajeshwari Medical College referred patients who met inclusion criteria to the Faculty of Dentistry for evaluation and treatment. The protocol was reviewed and approved by IRB No. RRDCH/PG-318/2018-19.

Inclusion criteria considered were:

1. Patients diagnosed with Tinnitus/MD by an Otolaryngologist using MRI, that excluded auditory neuroma.

2. Patients aged 18 years and older.

3. Presence of continuous bouts of MD symptoms.

4. Presence of a full complement of teeth with proportionately absent teeth (i.e., if a molar was absent on the right, it had to be absent on the left as well).

5. Having one premolar and molar in contact during right and left excursion, in nearly normal occlusal relationships.

6. Occlusal relationships of Angle’s class I and III, with the anterior teeth in positive overjet and overbite or almost in contact.

7. Patients with unresolved symptoms even after receiving treatment for MD.

Exclusion criteria were:

1. Anterior open bite and class II malocclusion where establishing an anterior guiding contact was not possible.

2. History of previous TMJ trauma.

3. Presence of internal derangement of temporo-mandibular joints as verified by Joint Vibratography Analysis (JVA).

4. Patients in whom conventional MD therapy resolved symptoms.

5. Patients who received prior treatment for TMDs, including occlusal modification treatments.

6. Patients aged below 18 years.

Informed consent was obtained before DTR corono-plasty from each patient for the treatment and collection of data on the severity, duration, and frequency of tinnitus/MD symptoms using questionnaires. An oral health history was also obtained where patients reported having MD symptoms including hearing loss, ear fullness, vertigo, and tinnitus, in at least one ear.

Before Immediate Complete Anterior Guidance Development (ICAGD), each participant underwent an excursive evaluation of left and right exclusion time/muscle hyperactivity using synchronized T-Scan 10/BioEMG III technologies (Bioresearch Assoc., Inc. Milwaukee, WI, USA and Tekscan Inc., S. Boston, MA USA) (Figure 1). Subjects firmly closed their teeth into their Maximum Intercuspation Position (MIP) and clenched for 1- 3 seconds, capturing two or three centric occlusion records (Multi-Bite).

Description of DTR therapy with the ICAGD Coronoplasty

Clinical maximum intercuspal position (MIP) photographs of each subject and their occlusal relationship in right and left excursion were obtained prior to any ICAGD. Pre-treatment day 1 left and right excursive T-Scan/BioEMG recordings were collected, and excursion durations (DT) and electromyography (EMG) levels were compared with DT and EMG values after ICAGD (Figures 2a, 3a, 4a).

ICAGD occlusal corrections were performed in two phases.

• ICAGD Phase I adjustments - Subjects' teeth were air-dried and closed into maximum intercuspal position (MIP) with an inserted articulation paper (Arti-Fol® Red, 8μ, Bausch, Germany) to perform right outward excursion on the right incisal edge of canine and then back into MIP. Similarly excursed to the left side till the incisal edges of the left canine, then slided back into the MIP. Corrections were made using the pre-treatment T-Scan/BioEMG recordings and led to the correction of extended excursive contacts, as marked with articulation paper, using finishing burs (Mani Dia-Burs, Japan) leaving the central fossa, tip, and marginal ridge contact points.

• Phase II - Modifications to the usual closure at MIP were done. Once all posterior quadrants went through ICAGD, measured calibration of unguided mandibular closures into MIP was performed. All high-force contacts were refined until the new MIP felt "comfortable". Closure adjustments were considered complete when only three contacts remained in Maximum Intercuspation Position (MIP), and the center of force trajectory aligned with the midline of the arch, indicating optimal occlusal balance. Post-treatment recordings were made in the same way as pre-treatment recordings to confirm correct excursion times (Fig. 2b, 3b, 4b). This allowed the muscles to recover following the occlusal corrections. At each of the three follow-up visits, subjects completed new questionnaires for duration, frequency, and intensity of symptoms. Finally, at the end of six months, the DT and EMG data were recorded. All subjects’ self-reported data were tested using Wilcoxon’s signed-rank test. Excursion time value and EMG levels pre and post-treatment were tested using repeated measures ANOVA and Post hoc LSD test (*statistically significant) (Alpha=0.05).

Results

Vertigo duration, intensity, and frequency decreased from baseline to three months post-DTR. Significant reduction in duration, intensity, and Vertigo frequency was noted (P <0.01). Post hoc analysis revealed a statistically significant difference in all pairwise comparisons (Table 1).

Tinnitus intensity and duration decreased significantly from baseline to three months post-DTR. However, tinnitus frequency increased from baseline (6.57) to one-month post-DTR (9.37) and then decreased to 3.06 three months post-DTR. Post hoc analysis of tinnitus intensity, duration, and frequency revealed a significant difference in all pairwise comparisons (Table 1).

A significant reduction in intensity, duration of ear fullness, and frequency of the symptoms was observed from baseline to three months post-DTR. Post hoc analysis of ear fullness intensity, duration, and frequency revealed a significant difference in all pairwise comparisons (Table 1).

Even in the least sensitive subject, the subject's dizzi-ness decreased in intensity from 8.9 to 0.61, duration reduced from 5.47 to 0.58, and frequency from 6.73 to 0.59. The tinnitus intensity decreased from 9.37 to 0.81, tinnitus frequency reduced from 6.57 to 3.06, while tinnitus duration reduced from 4.35 to 0.549, three months after ICAGD. Ear fullness intensity reduced from 8.74 to 0.60, duration from 1.90 to 0.58, and frequency from 6.72 to 0.58.

Excursion period significantly decreased six months after treatment on both left and right sides compared to pre-treatment values. This reduction on both sides was statistically significant. Post hoc analysis of excursion time revealed a significant differences in all pairwise comparisons on both sides (Table 2a).

On left lateral side excursion, muscle EMG levels in C (beginning of lateral excursion) showed a decrease from 46.65 to 40.12 from pre-treatment to one-month post-treatment. However, it increased to 60.63 after six months of treatment. This difference was statistically significant. The muscle EMG levels in D (end of lateral excursion as per ICAGD) decreased slightly from pre-treatment to six months post-treatment. This difference was statistically insignificant. Post hoc analysis on the left showed a significant difference in muscle EMG levels in C only between pre-treatment vs. six months and 1 month vs. six months. No significant difference was observed in the pairwise comparison of muscle EMG levels in D (Table 2a).

Muscle EMG levels on right side excursion at C increased from pre-treatment to six months post treatment. This change in values was statistically significant. Muscle EMG levels in D showed a statistically significant change from pre-treatment to six months posttreatment. Values increased from pre-treatment (9.26) to one month posttreatment (13.12) and then decreased at six months (9.91). Post hoc analysis on the right lateral side showed a significant difference in muscle EMG levels in C only between pre-treatment vs. six months and one month vs. six months. However, muscle EMG levels in D showed a significant difference between all pairwise comparisons except between pre-treatment vs. six months (Table 2b).

Discussion

The results of these 50 retrospective cohorts indicate that short disclusion time by correcting the excursion time with ICAGD resolved MD symptoms faster similar to the previous clinical reports on MD (Sutter, 2016, 2019).²¹

Considering the results obtained, it can be hypothesized that patients having TMD symptoms were wrongly diagnosed with MD due to similar symptomology. The etiology of MD has not been identified. If not, bimodal distribution would have been observed in the outcome of the treatment of these subjects, where positive outcomes would be observed in participants with a baseline diagnosis of TMD, while another group of subjects with a "true" MD would have received no benefit from ICAGD treatment. This study subjects reported improvement in ear fullness, tinnitus, vertigo, and hearing loss, which are the clinical signs used to diagnose MD.

Even in the least responsive subject, there was a significant reduction in dizziness intensity, duration, and frequency. Tinnitus intensity and frequency also decreased significantly, with a notable reduction in tinnitus duration occurring approximately three months after ICAGD. Additionally, ear fullness intensity, duration, and frequency improved. Overall, a significant reduction in symptoms was observed, even in the least responsive subject. Thus, it appears that DTR via ICAGD leads to substantial improvement in Ménière's disease (MD) symptoms, unless there is another variant of MD not represented in this sample of 50 patients.

This study supports the idea that temporomandibular disorders (TMD) and Ménière's disease (MD) may represent different diagnoses of the same underlying disease process, depending on whether the diagnosis is made by a dentist or an otolaryngologist. Addressing the true cause of Ménière's disease can help prevent the recurrence of symptoms and the progression or worsening of the disease. The authors recommend adopting a symptom screening protocol that includes Ménière's disease within the scope of temporomandibular disorders, to prevent unnecessary treatments and avoid wasting resources.

Limitations

Absence of controls, despite the small P values indicating high statistical significance could be viewed as a limitation. A more extensive study could be conducted in the future, with a few subjects randomly assigned to the control group and others to the ICAGD treatment group. The current study attempted to use subjects as their own controls to assess the effect of DTR occlusal adjustments.

Conclusion

The results of this study suggest that malocclusion, particularly bite force and bite timing, may contribute to the symptoms experienced by this group of Ménière's disease (MD) patients. This finding is significant, as occlusion has often been overlooked as a potential cause of MD in both medical and dental literature.

Conflict of Interest

No funding was received from any institution or funding agency for the production of this study.