The probity of conditioned pain modulation (CPM) in patients with myofascial pain syndrome - Clinical study.

Document Type : Original Article


1 Oral and Maxillofacial Surgery, Faculty of Dentistry, Cairo University, Cairo, Egypt.

2 Prosthodontics Department, Faculty of Dentistry, Cairo University, Cairo, Egypt.


Introduction: Tempromandibular joint disorders can affect the Tempromandibular
joint and/or the surrounding muscle component. Many theories were provoked to
explain the pathophysilogy of its chronic pain. Impaired endogenous pain
modulation mechanism theory is considered one of the most widely accepted
explanation of the pain controlling theories. Conditioned pain modulation can be
considered as reliable test to assess the pain inhibits pain phenomena, which
represents the inhibitory component of the endogenus pain modulating mechanism.
Aim: To evaluate the integrity of endogenous analgesia in patients suffering from
muscular pain related to myofacial pain dysfunction syndrome.
Patients and methods: Fifteen patients were recruited in this study. Trigger points
in the masseter muscle were identified and the pain rate was recorded after applying
manual pressure on these trigger points. Cold pressor test was then performed and
the pain rate was recorded again.
Results: There wasn’t a statistically significant difference between the mean value
of test pain stimulus scored by the patients before and after performing the cold
pressor test (P value 0.0961).
Conclusion: The results of this study showed that the endogenous pain inhibitory
system is impaired in tempromandibular joint disorders patients, however further
studies are recommended.