Temporomandibular disorder (TMD) is characterized by signs and symptoms such as clicking and/or popping sounds in the temporomandibular joint (TMJ), along with restricted range of motion and pain in the orofacial region. TMD may be associated with alterations in the pain modulation system due to chronicity and central sensitization. Therefore, quantitative sensory tests, such as the temporal summation test (TST) and pressure pain threshold (PPT), may be useful for assessing individuals with TMD symptoms.

To evaluate temporal summation in individuals with TMD symptoms.

This was an observational, non-probabilistic, cross-sectional study with convenience sampling. Individuals presenting signs and symptoms suggestive of TMD participated in the study. All participants underwent an evaluation process in which the TMD pain screening questionnaire from the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) was administered. Those who scored above two points were included in the study. Additionally, all participants completed the Jaw Functional Limitation Scale (JFLS-20). The assessment protocol involved measuring the PPT of the masseter muscle on the less symptomatic or pain-free side, followed by the TST, using a pressure algometer (MEDDOR). For the TST, 10 stimuli were applied at 30-second intervals, using the PPT value determined for the masseter muscle. Participants were instructed to rate pain intensity using the Numerical Pain Scale (NPS) after the first and tenth stimuli. For statistical analysis, the Shapiro-Wilk test was used to assess the normality of the sample, and the paired t-test was applied to compare NPS values between the first and tenth stimuli. Measures of central tendency and dispersion were expressed as mean and standard deviation (SD). Inferential analyses were performed with a 95% confidence interval, and a p-value < 0.05 was considered statistically significant.

Twenty-two individuals participated in the study, including 17 women and 5 men, with a mean age of 37.09 years (SD = 15.44). The mean JFLS-20 score for mandibular function was 3.29 (SD = 2.31). The mean PPT of the masseter muscle, which was used as the stimulus intensity for the TST, was 1.02 kg/cm² (SD = 0.46). The mean NPS score for pain perception was 4.77 (SD = 2.54) after the first stimulus and 5.82 (SD = 2.68) after the tenth stimulus. Pain perception increased between the first and tenth stimuli, and this difference was statistically significant (p < 0.01).

An increase in pain perception was observed during the Temporal Summation Test in individuals with TMD symptoms.

The findings indicate an increase in pain perception with repeated stimuli of equal intensity. However, given the relatively small variation in pain perception, it is unclear whether this response reflects a dysfunctional process. Further studies with larger samples are needed to explore the relationship between quantitative sensory test measures, such as pressure pain threshold and TST, in individuals with TMD.