Power calculation based on the detection of a difference of 3 mm in mean crest width difference between treatment groups, assuming a standard deviation of 3.0 mm (Schropp et al 2003), and with an alpha error defined to 0.05 and beta error to 0.20 (power 80%), revealed that 17 subjects in each treatment group will be required. Considering a 10% drop out, a total of 40 patients/teeth must be included.