Purpose   : Large volumes of information in the OR are ignored by surgeons when the amount outpaces human mental processing abilities. We developed an augmented reality (AR) system for dental implant surgery that acts as an automatic information filter, selectively displaying only relevant information. The purpose is to reduce information overflow and offer intuitive image guidance. The system was evaluated in a pig cadaver experiment. Methods   : Information filtering is implemented via rule-based situation interpretation with description logics. The interpretation is based on intraoperative distances measurement between anatomical structures and the dental drill with optical tracking. For AR, a head-mounted display is used, which was calibrated with a novel method based on SPAAM. To adapt to surgeon specific preferences, we offer two alternative display formats: one with static and another with contact analog AR. Results   : The system made the surgery easier and showed ergonomical benefits, as assessed by a questionnaire. All relevant phases were recognized reliably. The new calibration showed significant improvements, while the deviation of the realized implants was<2.5 mm. Conclusion   : The system allowed the surgeon to fully concentrate on the surgery itself. It offered greater flexibility since the surgeon received all relevant information, but was free to deviate from it. Accuracy of the realized implants remains an open issue and part of future work.