Occlusal key "First molars,the key to normal occlusion":Angle 1.They are the biggest teeth and their anchorage is strongest. 2.Their local position in the occlusal arch supports the main masticatory duty and operation. 3.They influence the vertical distance of upper and lower jaws,the occlusal height and aesthetic proportions. 4.As the permanent molars are the first erupting teeth of permanent dentition,they have "mighty"control on the teeth erupting later behind and in front of them,as they are forced to position to the already erupted and in occlusion functioning 1st molars. 190Occlusal key 1. They are the biggest teeth and their anchorage is strongest. 2. Their local position in the occlusal arch supports the main masticatory duty and operation . 3. They influence the vertical distance of upper and lower jaws, the occlusal height and aesthetic proportions. 4. As the permanent molars are the first erupting teeth of permanent dentition, they have “mighty” control on the teeth erupting later behind and in front of them, as they are forced to position to the already erupted and in occlusion functioning 1st molars. “First molars, the key to normal occlusion”: Angle