In yesterday's blog article, I discussed using Gates Glidden drills to open canal orifices and shape the coronal third of the canal. I mentioned that in most uninstrumented canals, the apex is around a size 15-20. I did not cite any sources on this. One of my main goals in writing this blog is to re-familiarize new dentists with the idea of evidence based dentistry. I know that we all heard this ad nauseam in dental school, but probably didn't full grasp the concept. Evidence based dentistry means that we treat our patients based on the current accepted dental research. This is a great idea from a philosophy standpoint but is much more difficult to fully implement in a busy private practice. As new dentists, we have the advantage of not yet contracting "Old Dog Syndrome" meaning we can still be taught new tricks. I will do my best to cite literature every chance I get here at The New Dentist Blog in an attempt to walk the walk of practicing evidence based dentistry. So without further ado...
The reference is "Comparison of the first file that fits at the apex, before and after early flaring." J Endod. 2001 Feb;27(2):113-6. Contreras MA, Zinman EH, Kaplan SK.
To summarize the study, the authors took mature mesial canals of 1st and 2nd mandibular molars and accessed the canals. Then they measured the first file that fits the apex and recorded the diameter of that file. Next they performed "radicular flaring" on the canals with either Gates Glidden #1 or Rapid Body Shapers. After "radicular flaring" was performed they measured the first file that fits the apex and recorded the diameter of that file. In group 1 (the Gates Glidden group) the first file measured 14.46 before flaring and 23.3 after flaring. In group 2 (the Rapid Body Shaper group) the first file measured 17.2 before flaring and 25.6 after flaring. This data shows that coronal binding of an instrument can give the operator false information about the apical size of a canal. Early coronal shaping can give us a better idea of the true size of the canal at the apex.
The reference is "Comparison of the first file that fits at the apex, before and after early flaring." J Endod. 2001 Feb;27(2):113-6. Contreras MA, Zinman EH, Kaplan SK.
To summarize the study, the authors took mature mesial canals of 1st and 2nd mandibular molars and accessed the canals. Then they measured the first file that fits the apex and recorded the diameter of that file. Next they performed "radicular flaring" on the canals with either Gates Glidden #1 or Rapid Body Shapers. After "radicular flaring" was performed they measured the first file that fits the apex and recorded the diameter of that file. In group 1 (the Gates Glidden group) the first file measured 14.46 before flaring and 23.3 after flaring. In group 2 (the Rapid Body Shaper group) the first file measured 17.2 before flaring and 25.6 after flaring. This data shows that coronal binding of an instrument can give the operator false information about the apical size of a canal. Early coronal shaping can give us a better idea of the true size of the canal at the apex.