This　paper　presents　a　novel　lightweight　navigation　system　for　oral　and　maxillofacial　surgery　(OMS).　An　external　curved　checkerboard　with　self-identifying　markers　is　set　as　the　reference　object　around　the　surgical　scene.　A　customized　oral　clip　with　a　micro　camera　is　designed　for　oral　localization　by　tracking　the　external　checkerboard.　Similarly,　the　dental　handpiece　is　also　equipped　with　a　micro　camera,　which　can　be　localized　like　the　clip.　The　spatial　model　of　the　markers　is　provided　by　binocular　stereoscopic　reconstruction.　A　front　surface　mirror　is　taken　up　for　the　registration　between　the　oral　cavity　and　the　camera　on　the　clip.　The　pivot　calibration　of　the　dental　handpiece　is　accomplished　by　our　proposed　calibration　method.　We　set　up　an　experimental　group　and　a　control　group　for　evaluation.　The　surgical　tools　of　the　experimental　group　were　approximately　30%　lighter,　35%　less　bulky,　and　90%　cheaper　than　those　of　the　control　group.　Our　system　yielded　the　comprehensive　navigation　accuracy　of　0.92　mm　whereas　the　accuracy　of　the　control　group　was　0.87　mm.　Results　revealed　that　our　system　can　achieve　similar　accuracy　compared　with　a　prevailing　system　at　a　lighter　weight,　a　more　compact　volume,　and　a　lower　cost.　Note　to　Practitioners　-　The　motivation　of　this　work　is　to　reduce　the　burden　on　patients　and　surgeons　during　OMS.　Current　commercial　navigation　systems　are　still　limited　by　the　burden　of　extra　cumbersome　fiducial　markers　and　high　hardware　costs.　Their　high　accuracy　benefits　from　the　large　size　of　fiducial　markers.　To　take　full　advantage　of　the　camera＇s　localization　effect,　we　propose　the　concept　of　＇marker-camera　inverse　projection＇,　i.e.,　reversing　the　roles　of　the　camera　and　the　markers.　In　this　way,　cameras　on　surgical　tools　detect　more　points　with　a　more　uniform　distribution.　Our　proposed　system　achieves　a　decent　balance　between　navigation　accuracy　and　hardware　cost,　which　facilitates　the　development　of　surgical　tools　to　be　lighter　and　more　economical,　and　involves　tremendous　potential　for　commercialization.　©　2004-2012　IEEE.