A 45 year old patient has 32 unrestored teeth. The only defects are deeply stained grooves in the posterior teeth. Clinical examination reveals no evidence of caries in the grooves. The most appropriate management is

no treatment.

prophylactic odontotomy.

conservative Class I amalgams.

application of a glass ionomer pit and fissure sealants.

application of a resin based pit and fissure sealants.