Objectives. The purpose of this study was to help ensure smooth and efficient internal communication among dentists, dental hygienists and dental laboratories in dental clinics and hospitals in an effort to boost their job satisfaction and the satisfaction of patients with dental services. Methods. The subjects in this study were the dentists and dental hygienists in 380 dental clinics and hospitals that registered with Korean Dental Association and were selected by stratified random sampling from Seoul, Incheon and Gyeonggi Province in consideration of the number of dental institutions located in the regions. A survey was conducted from December, 2008, to March, 2009, by male, by fax and in person. The response rate stood at 60.2 percent. The answer sheets from 430 participants who included 201 dentists and 229 dental hygienists were analyzed with a SPSS 12.0 program. Results. As for the level of smooth communication in the dental treatment room and the amount of efforts for that, the dental hygienists took a slightly better view than the dentists (p=0.019). Many of dentists who tried to have smooth communication in the dental treatment room pointed out a lot of conversation as the best effort for that (47.4%), and lots of the dental hygienists stressed the same as well (70.1%). In regard to the relationship of age to the level of smooth communication in dental laboratories and the amount of efforts for that, the dentists (p=0.005) and dental hygienists (p=0.001) who were at the age of 40 and up had the highest opinions. Conclusions. The departments of dentistry and dental hygiene should offer courses on medical communication and internal communication in dental clinics and hospitals to provide education about communication skills, and related teaching methods and teaching aids should be developed to improve the communicative competency of dental personnels.