Adults who have lost their fourth tooth on the upper left side can have their missing tooth restored with a denture or dental implant. Adults who have lost their fourth tooth on the left side of the mouth and cannot regrow a new tooth can use fixed or removable dentures to restore their missing teeth. The movable denture can be removed and worn by oneself, and the chewing effect is relatively poor; the fixed denture does not need to be removed and worn, and the chewing effect is better, but it is more damaging to the neighboring healthy teeth. Dental implants are fused with the surrounding bone through the biologically active coating on the surface, and crowns or bridges are installed on the implants, which are similar to natural teeth in terms of structure and sensation, and do not need to be removed or worn, and have stronger chewing function and are more aesthetic. If the fourth tooth on the left side of the above is lost, you need to pay attention to maintain oral hygiene and cleanliness, to avoid infection, it is recommended to take targeted treatment measures under the guidance of a professional doctor.