Oral health. Oral health, like medical health, has many aspects to it from oral pathology, oncology, public health, to dentistry and orthodontics, etc. There is no one field of study under the overall concept of oral health. Every field of science deals with oral health in some way, from biology, chemistry, and physics to chemical and mechanical engineering and bioinformatics.
Dentistry... Oral health falls on the line that split dentistry and medicine over 100 years ago. It could be called dentistry, oral pathology, oral medicine, maxillofacial development, otolaryngology, or a combination thereof. If you can be more specific, we could zoom-in toward one specialty. To relate to biology, I would connect through anatomy & physiology, embryology or biochemical physiology.