過破折第三大臼歯からの接触と顎閉鎖筋の両側再分布筋電図活動との関連性

Association Between Contact from an Overerupted Third Molar and Bilaterally Redistributed Electromyographic Activity of the Jaw Closing Muscles.

抄録

目的:

過破折した第三大臼歯の顔面側および/または顎関節症（TMD）の症状を示す側が、咬合接触数、咬合力、または前側頭筋（TA）および咬筋の表面筋電図（SEMG）活動の両側分布と関連があるかどうかを明らかにすること。

AIMS: To determine whether the facial side of an overerupted third molar and/or the side exhibiting symptoms of temporomandibular disorders (TMD) has an association with the bilateral distribution of occlusal contact number, occlusal force, or surface electromyographic (SEMG) activity of the anterior temporalis (TA) and masseter muscles.

方法:

片側性顎関節症症状を有し、下顎第3大臼歯過蓋咬合1本を有する19名の患者を登録した。咬合接触と側頭筋前部および咬筋のSEMG活動を、咬間位（ICP-MVC）および突出端-端位（Pro-MVC）での最大随意的食いしばり（MVC）中に同時に記録した。過蓋咬合/顎関節症症状の左右差と、咬合接触回数、断面力値（左右の前方または後方の断面弓咬合力の全弓合力[SFV]に対する比と定義）、側頭筋および咬筋のSEMG活動量の左右差のΔ値との関連を分析した。

METHODS: Nineteen patients with unilateral TMD symptoms and one overerupted mandibular third molar were enrolled. Occlusal contacts and the SEMG activity of the anterior temporalis and masseter muscles were recorded simultaneously during maximal voluntary clenching (MVC) in the intercuspal position (ICP-MVC) and in the protrusive edge-to-edge position (Pro-MVC). The associations between the side of overeruption/TMD symptoms and the Δvalues of the differences between the right- and left-side values for the number of occlusal contacts, sectional force value (defined as the ratio of the anterior or posterior sectional arch bite force of the right or left side to the total arch force [SFV]), and SEMG activity of the temporalis and masseter muscles were analyzed.

結果:

過蓋咬合側(P < .050)は、症候性側(P > .050)ではなく、Δ値との関連を示し、100％、75％、50％のプロトラッシブ・クレンチング位では、非過蓋咬合側より後弓のSFVが高く、側頭筋SEMG活性の値が低く、100％および75％のプロトラッシブ・クレンチング位では、後弓の咬合接触回数が多かった。

RESULTS: The overeruption side (P < .050), but not the symptomatic side (P > .050), showed an association with the Δvalues, with higher SFVs of the posterior arch and lower values for temporalis SEMG activity in the 100%, 75%, and 50% protrusive clenching positions and larger numbers of occlusal contacts in the posterior arch in the 100% and 75% protrusive clenching positions than the non-overeruption side.

結論:

咬合のパターンは、顎関節症の症状ではなく、咬合接触の数や分布、咬合力、側頭筋SEMG活性と関連していた。

CONCLUSION: The pattern of occlusion, but not TMD symptoms, had an association with the number and distribution of the occlusal contacts, occlusal force, and temporalis SEMG activity.