BackgroundThe　existing　augmented　reality　(AR)　dental　implant　surgery　navigation　system　usually　uses　markers　to　complete　image　guidance.　However,　markers　often　affect　dentists＇　operations　and　make　patients　uncomfortable.　MethodsTo　solve　the　problems　caused　by　markers,　this　paper　proposes　an　effective　marker-less　image　guidance　method.　After　initialisation　is　completed　by　contour　matching,　the　corresponding　relationship　is　obtained　by　matching　the　feature　points　between　the　current　frame　and　the　preloaded　initial　frame.　The　camera　pose　is　estimated　by　solving　the　Perspective-n-Point　problem.　ResultsThe　registration　error　of　AR　images　is　0.731　+/-　0.144　mm.　The　planting　errors　are　1.174　+/-　0.241　mm　at　the　neck,　1.433　+/-　0.389　mm　at　the　apex　and　5.566　+/-　2.102　degrees　for　the　angle.　The　maximum　error　and　standard　deviation　meet　the　clinical　requirements.　ConclusionsWe　demonstrate　that　the　proposed　method　can　accurately　guide　dentists　to　perform　dental　implant　surgery.