 Under local anesthesia, 2 mandibular third molars will be removed. Microdialysis sampling in the extraction socket will be performed with pre- and post-surgical biopsies. Patients will receive a COX inhibitor as an analgesic drug for the post-operative pain. Outcomes evaluated will include clinical pain response, gene expression profile using microarray and quantitation of related proteins after oral surgery and the interaction of these factors with analgesia by a COX inhibitor. By studying these responses in patient samples for each genotype non-variant homozygote, heterozygote and variant homozygote from the COX-2 gene, we will attempt to replicate and extend previous findings on the role of genetic factors in the inflammatory process, clinical pain and variation in response to analgesic drugs. 