Inadequate isolation of the operative field Absolute isolation is indicated to reduce two issues that cause post-operative sensitivity generated by penetration of saliva into the operative field: contamination of the cavity by microorganisms that cause pulp inflammation and contamination by humidity, which harms the bond and facilitates marginal leakage . The study of Auschill et al.showed that the type of isolation, with a rubber dyke or cotton wool rolls, has no influence on the occurrence of post-operative pain, provided that cavity contamination is avoided.