In any scientific study that intends to make inferences about an entire production of endodontic files its primary objective, the sample size is a very important feature for having sufficient statistical power. In estimating unknown parameters, larger sample sizes generally result in greater statistical confidence. Unfortunately the clinician rarely has that opportunity. If he uses 10 out of 100,000 files, that’s only a 0.001% chance that all of the others are the same. He relies on the manufacturing regulatory procedures for confidence in using every single instrument as 1 in 100,000 or the production number. In other words, the clinician relies on the one that comes out of the box. In our evaluations and in our imaging we make the same sample selection as does the clinician, the one that comes out of the box. With that selection we make the ethical commitment that every image we show and every test we conduct is unaltered and as independent as possible from operator influence.

Recently we received a complaint from Komet that the SEM we received from NOVA University and featured in a previous blog was not representative of their files. Their claim may be entirely valid. One out of the box may not be a representative selection but it is the selection upon which the clinician relies. If Komet would like to provide us with us with a statistical analysis and standard deviation of what is representative, we would welcome the opportunity to post their analyses and images.