I put a crown on my upper central incisor but my right tooth got broken and the crown fell down just one week after putting the crown.
Whqt shall I do? And how to protect the other one?

Sorry could you explain a bit better I don't understand?

What were you doing when your tooth broke? Was the tooth that broke the same one that the crown was on? What kind of crown was it? (porcelain fused to metal/full porcelain both made at a lab or an acrylic one made in the office)

6 years ago I do a surgery in the gum just above the upper right central molar to remove a dental cyst.
I delay I treating the root canal of the upper central molars,after 2 years from the operation I do a root canal filling.
after that by 1 year the color of the right upper molar change,so we remove the root canal filling and put a new one as my doctor said there is infection.
one year ago the color of the right upper molar become dark yellow some times it seem as yellowish green.
3 weeks ago I begun to put a crown over the upper 2 central molars the crown is metal covered with porclein.
after just one week from putting the crown, the right one get broken during eating,the food wasn`t hard at all ,but it was not very soft.
the doctor said that the tooth was very thin after the root canal filling and if he had seen the x-ray before he would never do the crown.
but the left one is thicker than the right.
do you think that it is possible that the right one would full very speedly as the right?
and how I could manage now the situation of the right one ?Is post crow is the only solution and what is its types? Finally how could I behave with these tooth to help them to live longer and to prevent their breake and falling?
sorry for being so long but I am really worried

6 years ago I did an operation to my gum just above the upper right central molar to remove a dental cyst
I delay in the root canal filling of the upper central molars after the operation by 2 years
one year after diding the root canal fillig of them the right one begun to change in color , the doctor said there is infection so we remove the root canal filling of the right one and put a new one
1 year ago the color of the right one became dark yellow and observed
so I went to the doctor 3 weeks ago to put a crown
he put it metal covered with porclein and put 2 one over the right and one over the left
but just 1 week after putting the crown the right one get broken during eating
the food was not absolutely hard but it wasn`t really soft
the doctor do an x-ray and said that the tooth was very thin after the root canal filling and if he saw the x-ray before he would never put the crown

The dentist should have taken the x-ray before even starting the crown! Perhaps it should be his expense to fix it right for you with either a post and crown or an implant?? No dentist should EVER do treatment without the appropriate x-rays.

My teeth aproved to be very thin after the root canal filling and the crown
Also we found a large chronic abcess just above the upper right central incisor as the doctor left a space between the teeth and the root canal filling
I ask a lot of doctor but I am confused
How could I manage?
And how about the fiber postcrwn?

Thanks for your caring