The most important problem of the present dental treatment and care is how to control the occlusal-force which is one of two main elements to maintain the health of the stomatognathic-system. Caucasian have the tendency of skeltal class III, but Mongolian often show class II. So, many Mongolian peaple have characteristics such as large quantity of momentum and the habitude with peculiarity of the canine teeth of the functional side, and we can find the looseness of the temporomandibularis joint of Mongolian. As a result, the canine teeth of Mongolian are easily worn out and form facet on their incisal edge. Then Mongolian peaple often have the premature-contact or the occclusal interference. Therefore they may easily lose their molars as years go by. And these seem to lead to the higher frequency of posterior bite collapse Mongolian show than that Caucasian show. Dentists often undergo such cases with posterior bite collapse as they show poor and unstable prognosis with no treatment to improve the teeth position of class II. The term of “Interdisciplinary Approach in Clinical Dentistry (IDA) ” has been used for several years. Based on those findings above-mentioned. this report shows a clinical case along the IDA in cooperation with a orthodontist and a subcontract technician.