Abstract :
Teeth are one of the important organs in the human body, especially in the human digestive process. Dental organs can be affected by a variety of problems and diseases, but to know it is necessary an expert or dental expert. While the ratio of the number of dental medical personnel is not ideal with the number of Indonesians, especially in the province of Central Java. In addition, pandemic conditions that make people's physical activity limited (physical distancing), therefore a system is needed that can replace the role of dental experts to diagnosis dental problems and diseases. In this study the authors created a system of disease diagnostic experts using web-based forward chaining. Forward chaining method is used because it can work maximum in determining conclusions when problems start from data collection or facts, in this case the symptoms felt by the user. However, the author of this expert system can only detect 7 types of dental diseases only. The initial diagnosis of this expert system can help the next treatment and solution of the disease. In accuracy testing using confussion matrix method resulted in system accuracy quite well with a value of 76,6% of some cases tested. In black-box testing test generate test log in, test case add disease data, test case change disease data, test case delete disease data, test case add symptom data, test case change symptom data, test case delete symptom data each worth 100%. In whitebox testing, the program's basic paths are tested for possible execution paths. The testing phase starts from converting the source code of the function to be tested into a flowgraph form, cyclomatic complexity calculation, and determining the basic paths of the program. Keywords: Expert System, Dental Disease, Forward Chaining, Black-box, Confusion Matrix.