1, the reason of gingival black line is generally the precipitation of metal ions from porcelain teeth. Although the black line cannot disappear once it is produced, this situation can generally be controlled and improved by replacing all-ceramic teeth without metal inside or adding shoulder porcelain when making porcelain teeth with metal inner crowns.

2, brushing your teeth has an odor, it is not recommended to brush too hard every day, which may cause gum inflammation, or porcelain teeth fall off, find out the cause of the odor, and treat it symptomatically. Most of them are related to poor sealing between porcelain teeth and abutment teeth. It is recommended to see a doctor.

3, it is not impossible to make teeth that have already made porcelain teeth. When pulling out the original porcelain teeth, it is not excluded that a small number of teeth need to be polished, but it must be within a safe range, otherwise the doctor will not dare to do it for you. And if your abutment itself is very short, some of it can be extended by piling, and it is not impossible to find it.

Because I am not in Wenzhou, I don't know the local hospitals, so I suggest to find a regular stomatological hospital for treatment. hope this helps