The number (quantity) of clinic staff members was positively associated with net income in 1996. However, in 2006, the number of staff members was no longer associated with net income. Instead, net income was associated with the types of services provided or the source of payment for those services. These results suggest that financial retrenchment has occurred in private dental clinics MK-2206 price in the recent years. Using data from a survey on the management of private dental clinics in October, 2008, 1240 private dental clinics were categorized into quintiles

according to net income. The higher quintiles (having higher net income) had younger owners (dentists) and larger median values of the number of patients per month. The number of full-time dental hygienists increased with the level of quintile (Fig. 5). Private dental clinics established after 1989 were more frequently categorized into the highest or second

highest quintile compared to those established before 1989. Moreover, the proportion of income from treatments not covered by health insurance in the total income gradually increased from the lowest quintile (4.1%) to the highest quintile (8.5%). These results suggest that private dental clinics opened after 1989 (new), and having dental hygienists (dental hygienists may conduct dental maintenance) had a large net income, suggesting that they may be better managed, they may have a different case-mix of

care, or they may have different sources enough of revenue. MG-132 Prevalence of dental caries has decreased, while that of periodontal disease has remained increasing [8]. Moreover, the number of private dental clinics has been increasing. Therefore, dental treatment needs may have shifted from dental caries to periodontal disease. As young dentists may have received new information, especially on periodontology, they employ dental hygienists, run a system of supportive periodontal treatment in their clinics, and consequently, have large net income. Analyses using data from the Central Social Insurance Medical Council also showed that dental clinics with more dental hygienists made higher profits [9]. A similar association between employing dental hygienists and income of dentists has also been reported in the United States [10] and [11]. Moreover, as young dentists have knowledge of dental implants, they treat patients using dental implants, which is not covered by public health insurance and brings in a large net income. Fig. 6 shows changes in the net income as well as total expenses of private dental clinics from 1996 to 2010, based on surveys conducted by the Japan Dental Association [5], [7] and [12]. Net income decreased from 1996 to 2004 with the lowest net income in 2004, after which point the value gradually increased until 2008.