Molecular diagnosis, through the application of molecular techniques, has made it possible to study microorganisms present in the onset and progression of dental caries, periodontal disease, and endodontic failures. Molecular techniques allow the detection and quantificationof the genetic material of deoxyribonucleic acid (DNA), ribonucleic acid (RNA) or proteins, allowing the study of the complete genome or specific DNA sequences, they arise as a need to detect difficult or slow growing microorganisms in cultures. The most widely used technique is the polymerase chain reaction (PCR) that allows the amplification of small segments of genetic material using primers, it is an economical, precise, sensitive and fast method for the detection of microorganisms. This bibliographic review article will serve to report on the advances in molecular techniques used for diagnosis in dental practice.