Yes it is. Dentistry, by nature, has always had to deal with respiratory infections which is why there are so many precautions that are always in place. Treatment rooms are disinfected for every patient, instruments are sterilized for each patient, staff members have always worn masks and now wear face masks as added protection. Modern offices use hi-tech air filtration systems to purify the air in each treatment room including UVC lights to kill viruses. Technically speaking the dental staff is more at risk than a patient is. But overall, dental offices are very safe.