I had a very similar experience when I was in Ecuador. I needed to get a root canal and the crown did last a little longer, about 28 months. However, when I went to the dentist a couple weeks ago here in the U.S. he said the decay was so bad that he thought he would have to pull the tooth. The good news is that he saved it but for everyone out there be very careful if you have to go to the dentist in a Latin country. Honestly, if you are looking for a dentists in Matamoros I would just try to go see someone in Brownsville.