Can I get implants after 16 to 20 years of missing teeth?

Yes.  Many times there is adequate bone even after decades of missing teeth.   Unfortunately, there are times when some areas are lacking in needed bone structure..  In those areas where there is a lack of bone some grafting may be in order to gain back that missing structure; another option may include not grafting those areas but rather placing implants only in the areas that there is enough bone and having fixed bridges that connect to those implants.The short answer is that you should make the first move and find a reputable Doctor to determine if you are an implant candidate and move forward from there.  Go get back the confidence to smile proud and gain back the ability to properly chew and enjoy your food.

You certainly may be able to get implants. I would recommend seeing a periodontist (gum specialist) to evaluate your bone and teeth. Some areas may not be suitable;others may be with bone grafting. You don't necessarily need one implant per tooth lost...you may be able to bridge or connect some;you may not need the very back molars replaced,etc. Find a good specialist and general dentist that can work together and determine what is best for you. It will be worth it! Good luck!

These are all excellent questions and yes, it is possible to get implants if there is enough bone left.  The only way that can be determined is to have a dentist do an evaluation of the condition of your mouth.  I would encourage you to at least get an exam to see what your options are.  Find a dentist you trust and have a conversation.  I am sure they will set your mind at ease and help you make a good plan.  Good luck!