My dentist says my lower gum has a low ridge and it is too hard to make a denture thatbfits. is this true?

Maybe: Traditional complete dentures depend on residual bone ridge for support. Loss of bone will compromise the stability and support for a denture. This is particularly true in the lower jaw where tongue movement may dislodge the denture. Ask about implants to see if you are a candidate. Consider getting a second opinion perhaps, particularly by a dentist who is familiar with dentures and implants.

More difficult: Retention is the big problem and comfort can also be a problem if enough ridge is gone. Retention and comfort can be added with placement of implants.

Implants: If you have been missing teeth for a while then the bone in your jaw does start to shrink or get smaller. Lower dentures are usually harder to wear then upper dentures. One solution to that is to have implants place to retain the lower denture.

Yes it is: The lower dentures are always more challenging, as the ridge height decreases it looses it's ability to hold and retain a denture.

Sometimes, but...: While this is sometimes true, i would suggest that you see a prosthodontist to get a second opinion and find out your options. Implants may be an option to help retain the denture.

Yes: Yes can be true, the amount of bone loss in the mandible can be so much that it is difficult to make a fuctional denture. It is better on those cases to have some implants placed.

Very well could be!: Many individuals have poor ridges after their teeth are extracted. There is no way to predict this prior to tooth extraction. A poor ridge equals a poor fit, poor retention and poor function. Your best best to avoid being a dental cripple is to consider an implant retained over denture. You will be amazed at how well you will function and the comfort.