It has been nearly 90 years since a dentist first fabricated a dental appliance for a patient with snoring. Since then, mandibular advancement devices or MADs have become a common treatment for obstructive sleep apnea and are used to increase the caliber of the airway during sleep. Their primary use is for the patient who has snoring or mild to moderate, but not severe, OSA problems. Unfortunately, only a small amount of empirical data exists on the topics of long-term compliance, complications and contraindications for these devices. Nevertheless, it appears that only a small percentage of patients will quit using a MAD because of temporomandibular joint (TMJ) or masticatory muscle soreness. An even smaller percent of the long-term MAD users will get changes in their occlusion. Compliance reports suggest that only 50% of the patients will be using the device after 3 years. Overall, these data suggest that MADs should be carefully fabricated by dentists who work on a referral basis with sleep medicine physicians and patients using MADs must be monitored regularly for ongoing efficacy and for associated complications. The good news (with good data support for this conclusion) is that MAD's are a moderately effective treatment of snoring and mild to moderate OSA.