Recording the maxillomandibular relationship with the Aqualizer system prior to occlusal splint therapy for treating temporomandibular disorders: a randomized controlled trial

Abstract

Temporomandibular disorders (TMD) present a public health issue and are one of the most common musculoskeletal conditions causing chronic pain. This study compares the outcomes of occlusal splint therapy in patients with TMD following two different maxillomandibular relationship (MMR) registration techniques. 40 TMD patients were randomly allocated to MMR registration with the Aqualizer system (AQU) or with chin point guidance (CPG) prior to fabricating occlusal splints. TMD symptoms, subjective pain intensity, and quality of life (QoL) were recorded at baseline and after 3 and 6 months. The treatment led to an overall reduction of TMD symptoms in both groups (Conover test, p < 0.00001). TMJ sounds, TMJ pain with palpation and muscle pain with palpation subsided regardless of the type of MMR registration method used (Cohen's d > 0.8). AQU-based occlusal splints led to a better improvement of TMJ pain with maximum opening compared to CPG-based occlusal splints (Cohen's d = 0.9; CPG d = 0.13). In both groups, occlusal splint treatment had little to no effect on correcting lateral mandible deviation or improving restricted jaw opening. After 6 months occlusal splints in both groups had a large effect on improving subjective pain intensity (Cohen's d > 0.8), however, patients reported a higher QoL in the AQU group compared to the CPG group (Mann-Whitney-U-test, p < 0.05). The results of this study support the premise that occlusal splints are effective in relieving pain-related TMD symptoms. The Aqualizer can be considered for determining MMR in cases, where guided registration techniques are not possible.Trial registration: DRKS00031998.

Figure 1

Flowchart of trial phases according to CONSORT guidelines.

Figure 2

Average TMD symptom score (TSS) at baseline and after 3 and 6 months of occlusal splint therapy. P-values determined by the Friedman test and Conover post hoc test with a Holm–Bonferroni correction (*p < 0.05; **p < 0.0001; ***p < 0.00001).

Figure 3

Forest plot for visualizing the effect sizes of the MMR registration method on the reduction of TMD symptoms #1–6 after Aqualizer- or Chin point guidance-based occlusal splint treatment for (a) 3 months and (b) 6 months. Effect sizes were estimated by computation of Cohen’s d and 95% confidence intervals (CI).

Figure 4

Histograms showing the frequency of pain intensity scores 1–10 at baseline and after 3 and 6 months of occlusal splint therapy following MMR registration with the Aqualizer system (a–c) or chin point guidance (d–f). Vertical lines represent mean (solid line) and median (dashed line) pain intensity.

Figure 5

Patient perception on the impact of occlusal splint therapy on quality of life.

Figure 6

Results of the patient satisfaction questionnaire completed at the 6 months recall visit. Qn. 1 General satisfaction: I am satisfied with the entire treatment I received from start to finish. Qn. 2 Expectations: My expectations to the treatment were fulfilled. Qn. 3 Alleviation: The treatment helped alleviate my initial discomforts. Qn. 4 Wearing comfort: I did not encounter any problems while wearing the occlusal splint. Qn. 5 Recommendation: I recommend this type of treatment. Qn. 6 Comfort: Bite registration with the Aqualizer system was not uncomfortable (only AQU Group).