EFFECT OF REPEATED MICROWAVE DISINFECTION IN WET ANDDRY CONDITION ON LINEAR DIMENSION OF ACRYLIC DENTUREBASE RESINABSTRACTIntroduction:Increasing awareness amongpeople has caused tremendous changes inhealth care sector. It is the legal and ethicalresponsibility of the dental practitioner toprevent cross contamination between thepatients, staff members and to him or herself.Emergence of many barrier techniques havebeen followed in clinics as well as in dentallaboratories. With increase in prevalence ofinfectious diseases nowadays, the concernregarding infection control in dentistry isundergoing a dramatic change and emphasison sterilization and disinfection procedure hasbecome a major concern.AIM -To evaluate the effect of repeatedmicrowave disinfection in wet and drycondition on linear dimension of acrylicdenture base resin.Material and methods– 30 rectangularspecimens (65mm x10mm x3mm) werefabricated using stainless steel dies (ADAspecification no. 12) from heat cure denturebase resin for evaluation of linear dimensionchange. Specimens were divided into threegroups (n =10). The first group was kept aspositive control whereas the other two weresubjected to microwave disinfection in wet anddry conditions. The specimens were tested forlinear dimensional change using video zoommicroscope. Data obtained by testing wascompiled and was analyzed using ANOVA andPost-hoc tests.Results- Results showed change in lineardimension was observed in wet disinfectiongroup compared to dry disinfection and controlgroup, whereas no statistical significantdifference was observed in control and drydisinfection group.Conclusion: Within limitation of this in studyit was concluded that since no significantdifference was found between dry disinfectiongroup and control group, dry disinfection canbe used as an alternative to chemical ormechanical method of disinfection withoutaffecting the linear dimension of the denturebase resin. Since wet disinfection causedhigher shrinkage, should be used cautiouslyKeywords:microwave disinfection, lineardimension, acrylic resin, micro- organisms..INTRODUCTIONWith increase in overall life span of elderlypeople because of better medical facilities,there is tremendous increase in denturewearing population1. Acrylic resin since itsintroduction in 1937 by W.H White has beenan extremely popular in fabrication ofremovable denture due to its certain desirableproperties like aesthetics, easy manipulationand low cost.2,3,4Despite its superior physicaland aesthetic properties over previouslyintroduced denture materials, it is porous innature which makes it difficult to clean andhence it is susceptible to plaque accumulation5.The dentureprosthesisalsoget contaminatedduring fabrication and other procedures i.e.