The Seguridad Social only pays for extractions, if out of necessity, not out of choice.
Try to find a dentist that offers free regular check ups if you register with them, as many do.
Make sure you have the Tarjeta 65 for your region. Many dentists have agreements with the Junta that enables them to offer a small discount on dental care procedures.
Information on how to obtain this Tarjeta 65 that offers many benefits for pensioners, in the Library on our website.
If you need financial help to pay for dental prothesis, you can try to apply for a subsidy through Social Services at your Town Hall. Will depend on availability of funds, however.