the efficiency assessment of dental units using data envelopment analysis approach: the case of iran

background: during the last decades, the number of dentistry units increased significantly across the country. the aim of this study was to assess the efficiency of dental units of iran provinces regarding dental health inputs and outputs using data envelopment analysis approach. methods: in this applied descriptive-analytical study, the study population included all of iran 31 provinces. the output variables included dmft and dmft indices of 6-12 yr old students. the data about dmft and dmft indices were taken from 2013 nationwide school pupils screening program. input variables included active dental chairs located in the public sector, general dentists of public sector, general and specialist dentists of private sector by different provinces. the data were analyzed using deap software version 2.1. results: the lowest amount of scale efficiency was for tehran province (0.204) followed by isfahan province (0.205). provinces of isfahan, razavi khorasan, kerman, zanjan, hamedan, kordestan, golestan, yazd and tehran, iran had decreasing return to scale and provinces of gilan, west azerbaijan, mazandaran, fars, kermanshah, markazi, lorestan, qazvin, sistan-and-baluchestan, bushehr, alborz, hormozgan and khuzestan had increasing return to scale. conclusion: despite provinces of isfahan, razavi khorasan, kerman, zanjan, hamedan, kordestan, golestan, yazd and tehran which had a better situation in terms of the number of dentistry chairs, public dentists, general and specialist dentists of private sector than other provinces, they had decreasing return to scale. investment in dental primary health care, preventive and educational programs can be more cost-effective.