Description of dental problem: The right lower molar was missing and the left lower molar only had a remaining root, and the teeth were crowded and uneven. Best treatment plan: Fortunately, there are wisdom teeth on both sides of the jaw, so orthodontic treatment can be considered to replace the missing molars by moving the two large teeth behind the missing teeth forward, and the uneven teeth problem can be solved at the same time. If there are no wisdom teeth, orthodontic treatment is needed to fix the missing teeth after solving the misalignment problem.