We thank Dr Ballal for his detailed comments on our recent paper in the Journal. The intention of the study was to assess differences in microleakage between laser etching and conventional treatments, and to that end we deliberately minimized as many extraneous variables as possible from the experimental design. We agree that there are a number of potential shear forces which can develop in the cervical region, and this was one of the reasons why we placed the inferior margin of the test cavity in cementum and the superior margin in enamel. We have previously investigated laser etching of tooth structure in great detail,1-3 and in those studies we have examined shear forces as well as other variables which can affect the result obtained with laser conditioning. It would be interesting to examine the effects of occlusal loading on leakage as a purely mechanical effect, however this is difficult to reproduce on actual teeth, and for the current study we were more interested in the well known variable of thermocycling as a reproducible and stringent factor related to microleakage. In relation to the second point Dr Ballal raises, which is the use of various tracer dyes, there is a broad range of suitable agents which can be used, and we have used various agents in the past in our dental materials research. There is no one ideal dye to replicate the movement of oral fluid, nor does fluid movement correlate exactly with percolation of bacteria into cavity margins. The 3-ring structure of methylene blue and other dyes of the phenothiazine grouping bears similarity to the polyphenols and protoporphyrins associated with dietary stains and Gram negative oral bacteria, respectively. Both of these are clinically relevant. The actual molecular ring structure of methylene blue (with 3 rings) is smaller than Rhodamine B (with 6 rings) and thus the latter penetrates better, based on the simplistic concept of steric hindrance alone. Regardless, we would disagree that one single small molecule, be it Rhodamine B or methylene blue, could replicate the leakage patterns of the battery of metabolites (small molecules), or enzymes and toxins (large molecules) that could be involved in leakage. There is the additional issue that Rhodamine B is a well known photosensitizer, unlike methylene blue which poses less operator issues in terms of handling and stability. Methylene blue is in common use for the assessment of microleakage, as gauged by the contemporary (2007–2008) literature in adhesive dentistry and in the assessment of dentine permeability.4-8 Use of immersion rather than vacuum methods is commonplace with methylene blue tracer dyes in such studies, and is in line with our work on adhesive interactions; we agree however that vacuum methods may be appropriate when considering the root canal situation, where diffusion alone would not give adequate penetration over time. In relation to the two final points, in our study, a 40-second light curing period was used as this is known to be adequate for both quartz tungsten halogen and LED curing light sources, again based on our own prior work9. Finally, the cervical regions of the teeth were sectioned through their centre at right angles (thus bucco-lingually) using a diamond saw, in order to subsequently measure the actual extent of dye penetration on the buccal and lingual cavity margins. This was not explained in detail in the manuscript and was a minor oversight, in retrospect. We thank Dr Ballal once again for his comments, and hope that our paper and the further comments above facilitate his own dental research endeavours in dental materials science.