Oral　localization　is　widely　used　in　oral　and　maxillofacial　surgery　(OMS).　Most　existing　navigation　systems　adopt　stereo　optical　devices　to　track　fiducial　markers　for　oral　localization.　However,　they　still　suffer　from　line-of-sight　(LoS)　occlusion　and　field-of-view　(FoV)　limitation.　This　article　presents　a　robust　oral　localization　system　that　utilizes　multicamera　tracking　of　self-identifying　markers　to　address　the　above　issue.　A　customized　oral　clip　with　self-identifying　markers　on　its　curved　surface　is　designed,　which　is　firmly　fixed　within　the　patient＇s　oral　cavity.　Before　surgery,　an　accurate　method　based　on　intraoral　scanning　is　developed　to　register　the　patient＇s　oral　cavity　with　the　markers,　of　which　the　registration　error　is　less　than　0.1　mm.　Second,　a　cylindrical　marker　is　applied　for　calibrating　the　converging　multicamera　system　to　avoid　the　blurry　sight　problem.　During　surgery,　a　multicamera　tracking　method,　integrating　nonlinear　optimization　and　an　extended　Kalman　filter　(EKF),　is　proposed　to　localize　the　oral　cavity.　We　establish　a　simulated　environment　to　test　the　accuracy　and　robustness　of　the　tracking　method.　Additionally,　we　set　up　a　real　platform　using　a　phantom　oral　cavity　to　validate　the　feasibility　of　each　proposed　method.　Results　reveal　that　our　system　yields　a　closer　trajectory　(0.37　mm)　to　the　ground　truth　than　that　of　a　stereo-camera　tracking　system　(1.58　mm),　and　exhibits　a　certain　robustness　against　camera　occlusion.　　©　1963-2012　IEEE.