From a coronal view of a section of the posterior teeth, the lingual cusps of the upper teeth stamp into the fossae of the lower teeth and the buccal cusps of the lower teeth stamp into the fossae of the upper teeth.
The lingual cusps of the upper teeth and the buccal cusps of the lower teeth are therefore called Stamp Cusps.
The buccal cusps of the upper teeth and the lingual cusps of the lower are called the Shear Cusps, which is because they pass closely by the stamp cusps on their way to occlusion to shear the food.From the coronal view, we will find a contact between the upper shearing buccal cusps and the lower buccal stamp cusps.
This contact is called an A contact.The common contact between the stamp cusps is a B contact.A third contact exists between the upper lingual stamp cusp and the lower lingual shear cusp.
This is called a C contact.If we obtain an A and a B contacts in centric occlusion without the C, or if we obtain a B contact with a C contact without the A, we will still have good stability.
This is because the closure forces will still be within the perimeter and in the long axis of the teeth. However, if we obtain an A and a C contacts without the B in centric, the parallelogram of force will be toward the buccal of the upper and the lingual of the lower. In other words, if the B contact is not obtained, we will have a case of malocclusion, or an unstable centric.

#牙医IG翻动派[超话]##微博健康公开课#

詹姆斯更新IG晒照：单场至少30分20板10助 湖人队史第三人！

前日NBA常规赛，湖人在客场通过双加时以145-144险胜勇士。

詹姆斯本场比赛出战48分钟，25投14中，三分4中2，罚球6中6砍下36分20篮板12助攻大三双。

今日詹姆斯更新IG动态转发数据，他成为湖人队史继埃尔金-贝勒和贾巴尔之后第三位单场砍下至少30分20篮板10助攻的球员！

努力周二[干饭人]
ig又崩了，
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2024.01.15-17，19-22，24-27,29
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