When you smile, you will see most of your gums exposed or you will not be able to see most of your lower teeth, but only most of your upper teeth.
Deep overjet refers to the vertical distance between the teeth when they bite together. Deep overjet means that the maxillary incisors exceed the middle 1/3 of the mandibular incisors when they bite together, and a normal bite should have the maxillary incisors covering the mandibular incisors within 1/3 of the mandibular incisors when they bite together. In deep overjet, the bite is deeper, so the gums are exposed when smiling and the lower teeth are not visible.
Long-term deep overjet, jaw movement is restricted, which will lead to limited mouth opening and bite muscle pain. It is recommended to go to the orthodontic clinic for checkups, and wear orthodontic appliances to correct the deep overjet, so that the teeth can return to the normal occlusion state.