INTRODUCTIONDuring the restoration of an affected tooth, if any margin between the composite restoration and the affected tooth is open, micro-leakage may occur1. Microleakage is a phenomenon in dentistry resulting from an imperfect adhesion that allows the movement of bacteria and fluids between the restoration and the tooth of interest2. When a composite restoration is placed and cured through curing, shrinkage occurs. Research has shown that the percentage of gaps between composite restorations can be variable; between 14% and 54%3. This can lead to an increased risk of microleaks and is of concern to both the dentist and the patient. Other existing causes of microleakage include: continuous light curing methods4 and pre-restorative home whitening5. The effects of microleakage include: increased sensitivity, secondary caries, discoloration of the composite material, restoration failure and/or pulp pathology or pulp death1. The existence of microleakage in dental restorations was first identified in scientific research in 19126. In a study conducted by Harper (1912), air pressure was used to penetrate the surface between an amalgam restoration and the cavity preparation7. By applying pressure through a hole in the pulp floor, Harper was able to quantify the amount of pressure needed to establish a leak through the emergence of bubbles from the margins of the restoration. Research has come a long way since Harper first recognized microleaks. Adaptations of new materials used when placing composite restorations such as BondAband, a light-curing glass ionomer cement, have been shown to reduce marginal microleakage in posterior restorations8. A decrease in microleaks has also been demonstrated with the use of a…half-paper…air pressure test. Dent Rev. 1912; 26: 1179-1198.7. Aziz RD, Gonzalez NAG, Kasim NHA. Microleak test. Annals of Dentistry 1997; 4(1): 31-37.8. Chapman Kenneth W., Crim Gary A. Reduction of microleakage in Class II restorations: an in vitro study. Opera Dent 1994; 25(11): 781-785.9. Siso HS, Kustarci A, Göktolga EG. Microleakage in resin composite restorations after antimicrobial pretreatments: effect of KTP laser, chlorhexidine gluconate and Clearfil Protect Bond. Opera Dent. 2009; 34(3): 321-327.10. Gharizadeh N, Moradi K, Haghighizadeh MH. A study on microleakage in Class II composite restorations using four different curing techniques. Opera Dent. 2007; 32(4): 336-40.11. Bagis YH, Baltacioglu IH, Kahyaogullari S. Comparison of microleakage and layering methods of silorane-based resin composite in large class II MOD cavities. Opera Dent. 2009; 34(5): 578-585.