顎口腔系の状態と全身状態との関連に関する研究

－咬合支持領域の大小が頭頸肩部筋力に及ぼす影響－

	日　本　大　学	武　田　友　孝
（共同研究者）	同	石　上　恵　一
	同	島　田　　　淳
	同	月　村　直　樹
	同	高　山　和比古
	同	大　木　一　三

A Study on the Relation between the Stomatognathic
System and the Systemic Condition
-Concerning the Influence of Different Sizes of
the Occlusion Supportive Area on Neck Muscles-

Tomotaka Takeda, Keiichi Ishigami, Atsushi Shimada
Naoki Tsukimura, Kazuhiko Takayama, Katsuzoh Ohki
Nihon University School of Dentistry Department of
Removable Partial Denture Prosthodontics

ABSTRACT

We authors have attentions to the relation between the stomatognathic system and the systemic condition. And then we have a strong belief in that relation. As a part of these stuies, we lately studied the Influence of diferent sized of the occlusion supportive area on head muscular strength at the time of head anteflexion and some muscles activities using the Head-Neck-Shoulder Muscles analyzing system and electromyography analyzing system on 5 healthy athletes. And the following results were obtained.
1. The maximum muscular strength was recorded when using most wide supportive area splint (7+7) in all subject and tended to decrease with the lose of posterior supportive area.
2. The maximum muscular activity of the masseter and anterior tempolarlis were also recorded when using most wide supportive area splint (7+7) in all subject and tended to decrease as the outcome of a lose of posterior supportive area. And sternomastoid and tripedius had the same tendency, but it was only a very small difference compared with masticatory muscles.
These results were much the same with back strength (Ohiwa). And they were considered as follows;At first the lose of posterior supportive area occur the occlusal disharmony, and then the direction of occlusal force was any longer united that of masseter main muscle of occlusal force. So as to keep out of the pain in temporomandibular joint and periodontal ligament. These pains came into existence while strong clenching without enough posterior supporting area. Then above mentioned causes and so on had an effect on occlusal force so called clenching force and decrease it's performance.
And these decreasing oclusal force affected head neck shoulder muscular strength at the time of head anteflexion in some relations between Stomatognathic System and cervical region.
Such as 1 ; While clenching, the canalization in H - reflex which is an indiction of motor nerve loop, is remarkable, and that is proportionate to the strength of clenching. 2 ; When the excitation in the motor area of mastication is activated strongly by clenching, it expands into other motor areas and actives the cells which concern skeletal muscle of whole body in medullaty riticular formation.
3. The central incidence from mesencephalic tract of trigeminal nerve in which the neurons from masticatory muscles has the path which enters the anterior horns of first and second cervical vertebral as well as the path which enters motor nucleus of trigeminal nerve.
4 ; Existence of reflex system between trigeminal nerve and neck muscles as Trigemino-Neck reflex.
Consequently, when using mouthprotector without enough posterior supportive area and oral condition is badly in need for dental treatment like Prosthodontics, no muscle can work certainly. So a point of view safety and performonce enough posterior supportive area would be required. Thus wearing proper mouth protector and right oral health condition are able to be used for head - neck harm ptotection. And we dentists are in the hope of using the mouthprotector more widely.

　要　旨

　本研究では、咬合支持領域の異なるスプリントの装着が、前屈時頸部筋力および周囲の筋活動量に如何なる影響を及ぼすかを、運動時に強い噛み締めの見られる、２０歳代の男性５名を被験者として検討した。その結果、前屈時頸部筋力は、すべての被験者において最も咬合支持領域の多い７＋７スプリント装着時に最大値を示し、７＋７、５＋５、３＋３と後方咬合支持領域が減少するにしたがい、小となる傾向を示した。一方、咬筋、側頭筋の筋活動量はすべての被験者において, 7+7, 5+5, 3+3と後方咬合支持領域が減少するにしたがい、小となる傾向を示し、胸鎖乳突筋、僧帽筋後頸部においても同様の傾向が認められたが、その変化は咀嚼筋群に比べわずかであった。
したがって、咬合支持領域の少ないマウスプロテクターの使用や、歯欠損を放置したままの口腔内状態では、十分な筋活動が行なえず、安全面、パフォーマンス等の観点からも、十分な咬合支持領域の確保が必要と思われる。　