<prompt> Newly erupted teeth is covered by:PerikymataNasmyths membraneEnamel PearlsDentin  <response>: Ref. Grays anatomy. 41st edition. Page. 520NASMYTHS MEMBRANECovers newly erupted tooth.Membrane replaced by pellicle.Microbes invade pellicle to form plaque.ENAMEL PEARLS Occasionally found on root surface towards cervical margin.Importance: Predisposed to plaque accumulation following gingival recession.Perikymata Transverse wave like grooves appear to be the external manifestations of external manifestations of striae of retziusstriae of retzius.Seen in freshly erupted teeth or in tooth which is not subjected to abrasive forces.not subjected to abrasive forceAverage of 30 perikymatamm in cervical regionin cervical region and 10mm in occlusal regionThese may contribute to adherance of plaque material which results in caries. 