a badly chipped/fractured tooth as you describe will be difficult to keep long term. If the nerve is exposed, root canal treatment will be required followed by crowning. The overall strength of the tooth will be poor and it may not last very long.
A more predictable treatment to consider will be extraction and placement of an implant. This is a titanium replacement for the root of the tooth that will support a porcelain crown. The lifetime of this is very good and it functions and looks just like a normal tooth.
Alternatives include a bridge which is a porcelain tooth attached to the adjacent teeth or a removable denture. Both these options are less costly but usually less desirable.
If you fracture a tooth then please visit the dentist immediately especially as it may be very painful and affect chewing/speaking. He/She will be able to relieve any pain and provide a temporary tooth. Definitive treatment times vary according to the procedure from days to months, but at no time will you be left without a tooth.
