Background: Splints are a non-invasive, reversible management option for temporomandibular disorders (TMD) or bruxism. Clinical and cost-effectiveness remain uncertain.
Objectives: To evaluate splints’ clinical-effectiveness and cost-effectiveness for patients with TMD or bruxism. This evidence synthesis compared: i) all types of splint versus no/minimal treatment/control splints; and ii) prefabricated versus custom-made splints, for the primary outcomes: pain (TMD) and tooth wear (bruxism).
Methods: Four databases including MEDLINE and EMBASE were searched until 1 October 2018 for randomised clinical trials. Cochrane review methods (including risk of bias) were used for the systematic review. Standardised mean differences (SMD) were pooled for the primary outcome pain, using random effects models in TMD patients. A Markov cohort, state transition model, populated using current pain and Characteristic Pain Intensity (CPI) data, estimated the incremental cost-effectiveness ratio (ICER) for splints compared to none, from an NHS perspective over a lifetime horizon. Value of information analysis identified future research priorities.
Results: Fifty-two trials were included in the systematic review. The evidence identified was of very low quality with unclear reporting by TMD sub-type. When all sub-types were pooled into one global TMD group, there was no evidence that splints reduced pain (SMD (up to 3 months) -0.18 (95% CI -0.42 to 0.06); substantial heterogeneity) when compared to no splints or a minimal intervention. There was no evidence that other outcomes including TMJ noises, decreased mouth opening, and quality of life, improved when using splints. Adverse events were generally not reported, but seemed infrequent when reported.
The most plausible base case ICER was uncertain and driven by the lack of clinical effectiveness evidence. The cost-effectiveness acceptability curve showed splints becoming more cost-effective at a willingness to pay (WTP) of around £6k, but the probability never exceeded 60% at higher levels of WTP. Results were sensitive to longer term extrapolation assumptions. Value of information analysis indicated that further research is required.
There were no studies measuring tooth wear in patients with bruxism. One small study looked at pain and found a reduction in the splint group, mean difference (0 to 10 scale) -2.01 (95% CI -1.40 to -2.62; very low-quality evidence).
As there was no evidence of a difference between splints versus no splints, the second objective became irrelevant.
Limitations: There was a large variation in the diagnostic criteria, splint types and outcome measures used and reported. Sensitivity analyses based on these limitations did not indicate a reduction in pain.
Conclusions: The very low-quality evidence identified did not demonstrate that splints reduced pain in TMD as a group of conditions. There is insufficient evidence to determine whether splints reduce tooth wear in patients with bruxism. There remains substantial uncertainty surrounding the most plausible ICER.
Future work: There is a need for well-conducted trials to determine clinical and cost-effectiveness in patients with carefully diagnosed and sub-typed TMD, and patients with bruxism, using agreed measures of pain and tooth wear.