The objective of the thesis was to identify the optimal levels and mix of basic dental services (sealants and fillings for permanent teeth and extraction of primary teeth) provided to primary school children in two different dental settings: hospital-based and mobile dental clinics under specified resource, service need and setting preference constraints.

In order to get the final answer, the methodology was divided into four steps; dental caries and treatment need survey, resource study, parental willingness to pay (WTP) survey and the final step, using the data from these studies as input information for resource allocation by linear programming (LP). 

In the first step, dental caries and treatment need survey was performed in primary schoolchildren of five districts in Songkhla province served by different settings of dental services using WHO basic oral health survey methods. Multistage cluster sampling was done which included 712 children. Descriptive statistics and cluster logistic regression were carried out using R programme.

In, the second step, total resource available and the unit costs of dental services for schoolchildren between two settings of community hospital were estimated from a cross-sectional study where a community hospital in Songkhla was used. The unit cost was calculated based on simultaneous equation method in Microsoft Excel. 

The next step, WTP survey was implemented among 205 parents of primary school children who were examined in the first step. Parents were asked questions about their WTP for the different services as well as background information. Comparative information on caries process, treatment procedure and effectiveness was presented to parents. Each parent’s WTP was determined for three basic dental services in two different dental settings using a bidding game approach. Descriptive statistics and multilevel linear regression were performed using R software.

Finally, a linear programming model was used based on explicit identification of system objectives and resource constraints. The objective was to maximize benefits as measured by parental willingness to pay (WTP) for basic dental services provided to schoolchildren subject to constraints on total resources, service need and parental preferences among different dental care settings. LP was analyzed by the support of Microsoft Excel.  

The LP constraints included resources constraints, minimum treatment needs coverage and parental setting preference proportion. The resource constraints were 64,525 minutes of provider time, 35,179 minutes of assistant time, 38,055 baht of material cost, 14,594 baht of capital depreciation cost and 154,984 baht of support cost. The minimum needs coverage was 450, 495 and 743 cases of sealant, filling and extraction, respectively. The parental setting preference proportions between hospital and mobile setting were 0.6:0.4, 0.4:0.6 and 0.3:0.7 of sealant, filling and extraction, respectively. The WTP benefits produced per case were 226, 169, 226, 216, 123 and 118 baht of hospital sealant, mobile sealant, hospital filling, mobile filling, hospital extraction and mobile extraction.

Optimization was identified to require 270, 180, 552, 828, 228 and 532 cases of hospital sealant, mobile sealant, hospital filling, mobile filling, hospital extraction and mobile extraction, respectively. The optimal condition produced WTP 485,860 baht. The respective current services cases were 48, 281, 191, 170, 479 and 677 which produced summation of WTP 277,026 baht. The optimal service configuration produced WTP more than the current services 75.4%. 

In addition, interesting by products were produced from each step and presented as the following;

Dental caries indicators for secondary prevention, and combined primary and secondary prevention of children access to hospital dental service were significantly better than those who access to adjunct mobile dental service.

Among the basic dental services provided to primary schoolchildren unit cost of services provided in mobile dental clinic was lower than such services provided in hospital-based dental clinic.

Although the setting does not affect significantly the WTP for service directly, the estimated positive association between WTP and income is modified by setting. Mobile dental sealant was less preferred than hospital-based dental sealant. The opposite result was showed for filling and extraction. However, all three services, the setting-income interaction illustrated that WTP of mobile dental setting was being less when income increased.

In conclusion, based on the optimization analysis, the following services should be increased: hospital sealant, hospital and mobile filling, whereas the following services should be decreased; mobile sealant, hospital and mobile extraction.