What're the subspecialties of dental sleep medicine?

Dental Sleep Med: Dental sleep medicine is a subspecialty focus within Dentistry. There are no additional delineations of subspeciality focus of which I am aware (it is fairly subspecialized already). Dental sleep medicine primarily focuses on altered dentition which can worsen obstructive sleep apnea, and uses a variety of dental appliances to alter the resting position of the mandible during sleep to help.

Dent Sleep Medicine: Dental Sleep Medicine is not a recognized Specialty, however it is an area of concentration, a sub-specialty, that requires additional training. Dentists who practice Sleep Medicine, repairing and restoring the hard and soft oral cavity tissues, while the patient is under general anesthesia, requiring extensive anesthesia training above and beyond their Dental Degree.

None really: There a certifications offered in dental sleep medicine, based upon more hours of education and treatment performed.