There　is　a　lack　of　evidence　about　the　relationship　between　microorganisms　and　non-carious　cervical　lesions　(NCCLs)　due　to　limited　technologies.　A　group　of　78　patients　was　enrolled　for　microbial　16S　rRNA　sequencing　of　dental　plaques　on　normal　and　defective　cervical　surfaces.　Parallel　data　from　39　patients　were　analysed　with　paired　t　tests,　and　Fusobacteriales　exhibited　significantly　less　distribution　on　NCCLs　than　on　normal　surfaces.　As　a　result,　Fusobacterium　nucleatum,　the　most　common　oral　bacterial　strain　belonging　to　the　order　Fusobacteriales,　was　selected　for　further　research.　From　a　scanning　electron　microscopy　(SEM)　scan,　the　tooth　surface　with　Fusobacterium　nucleatum　and　Streptococcus　mutans　culture　was　more　intact　than　that　without　Fusobacterium　nucleatum.　Furthermore,　the　calcium　contents　in　groups　with　Fusobacterium　nucleatum　were　significantly　higher　than　that　without　it.　In　further　mechanistic　research,　Fusobacterium　nucleatum　was　demonstrated　to　adhere　to　and　disturb　other　organisms　as　well　as　producing　alkaline　secretions　to　neutralize　the　deleterious　acidic　environment,　protecting　the　tooth　structure.　In　conclusion,　microorganisms　and　NCCLs　were　confirmed　directly　related　through　adherent　bacterial　interactions　and　pH　regulation.　The　research　provides　a　new　perspective　and　experimental　evidence　for　the　relation　between　microorganisms　and　NCCLs,　which　guides　clinical　treatment　and　preventive　dentistry　in　the　future.