This article describes a simple method of applying a time series analysis to sample data sets using a free and open statistical software program, Language R.Records of new patients who visited 2 different university-affiliated orthodontic departments in 2 different countries were collected. Time series analysis was performed by applying Language R software. The data sets and codes were provided for tutorial and illustrative purposes.Using time series decomposition, the trend component and the seasonal variation were separated and visualized graphically.Time series analysis may be helpful to clinicians by providing a simple tool to evaluate patient characteristics and manage the practice.