There are an increasing number of dental specialists in Thailand especially within the Ministry of Public Health (MOPH), but information about their tasks’ characteristics is not well understood. This cross-sectional descriptive study aimed to explore the task proportion of specialists in MOPH’s hospitals and the determinants of their performance in three dimensions; work factors, health facility environment, and administrative environment. The results show that, aside from specialized dental services, 95.5% of dental specialists still provided basic services, and 68.2 % of them had documentary and administrative activities as part of their routine. On average, dental specialists allocated their working time to basic, specialized service, documentary and administrative works at a proportion of 41%, 48% and 11%, respectively. Work factors that might influence the performance of dental specialists were: 65.9% of respondents reported an intra-organizational agreement, 40.9% pinpointed the overwhelming burden of basic treatments over advance procedures. 18.2% reported low number of patients wanting specialized care, and 15.9% reported a shortage of general practitioners compared to work burden. Regarding health facility environments; 4.6% of dental specialists indicated lack of equipment for their advanced skills, while 31.8% mentioned absence of clear guidelines and systems for consultation or referral within a provincial dental service network. Regarding administrative environments; 38.6% and 43.2% of dental specialists pointed to a lack of policy and monitoring systems that support specialized dental services at provincial and regional levels, respectively. In conclusion, dental specialists in MOPH were responsible for basic and specialized services at similarly high proportions (41% vs. 48%), with additional documentary and administrative works. There are still rooms for development in terms of equipment adequacy, consultation and referral guidelines, policy direction and monitoring system.