Many. Airborne and blood borne pathogens. Exposure to chemicals, including mercury vapor, damage to eyes by debris and light from curing lights and lasers, general workplace hazards, hearing loss from dental handpieces, needle sticks, back and neck problems due to position and repetivess stress injury like carpal tunnel syndrome.
Infections. The mouth ks a very dirty part of the anatomy. Saliva can carry viral loads, .Such herpes, which can even cause a focal area of blind scar if saliva hits the eye. Hepatitis and aids can be spread by blood while performing dental care not to mention puncture of the dentist with a drill, etc.