• Journal of Oral Medicine and Pain
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• v.30 no.3
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• pp.345-351
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• 2005

The purpose of this double-blind study was to evaluate clinical effects of botulinum toxin type A (BTX-A) injection on myofascial pain syndrome (MPS) involving upper trapezius and compare with those of lidocaine injection. 21 patients presenting with active TrP1 and/or TrP2 in the upper trapezius over 6 months were selected for this study. The subjects were randomly divided into two groups; one group injected with BTX-A (15 unit of $Botox^{(R)}$ / 0.3 ml per trigger point (TrP)) and the other group injected with 0.5% lidocaine (0.3 ml /TrP). The clinical effects were evaluated by VAS and PPT at baseline, 2, 4, 6 and 8 weeks after treatment. BTX-A group showed persistent decrease of VAS values and increase of PPT values following treatment. While there was no significant difference in VAS values between BTX-A and lidocaine groups (p=0.347), there was significant difference in PPT values after treatment between two groups (p=0.000). The subjects received BTX-A showed noticeable improvement in PPT values after treatment, suggesting more reliable effect of BTX-A injection compared with lidocaine injection. The results of this study support that the direct injection of BTX-A to a TrP is an effective and safe treatment for MPS involving upper trapezius.

• Journal of Oral Medicine and Pain
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• v.34 no.3
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• pp.317-324
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• 2009

This study aimed to assess stiffness and elasticity of the masticatory muscle in the patients with the masticatory muscle pain using a tactile sensor and to investigate whether the masticatory muscle pain affects the facial expression muscles. From those who visited Department of Oral Medicine in Dankook University Dental Hospital, 27 patients presenting with unilateral muscle pain and tenderness in the masseter muscle (Ms) were selected (mean age: $36.4{\pm}13.8$ years). Exclusion criterion was those who also had temporomandibular joint (TMJ) disorders or any neurological pain. Muscle stiffness and elasticity for the muscles of mastication and facial expression was investigated with the tactile sensor (Venustron, Axiom Co., JAPAN) and the muscles measured were the Ms, anterior temporal muscle (Ta), frontalis (Fr), inferior orbicularis oculi (Ooci), zygomaticus major (Zm), superior and inferior orbicularis oris (Oors, Oori) and mentalis (Mn). t-tests was used to compare side difference in muscle stiffness and elasticity. Side differences were also compared between diagnostic groups (local muscle soreness (LMS) vs myofascial pain syndrome (MPS) and between acute (< 6M) and chronic ($\geq$ 6M) groups. This study showed that Ms and Zm at affected side exhibited significantly increased stiffness and decreased elasticity as compared to the unaffected side.(p<0.05) There was no significant difference between local muscle soreness and myofascial pain syndrome groups and between acute and chronic groups. The results of this study suggests that masticatory muscle pain in Ms can affect muscle stiffness and elasticity not only for Ms but also for Zm, the facial expression muscle.