The Impact of 4 Design Parameters in the Decision Making of Practitioner on an Endodontic Guide.

Objectives: The aim of the present study is to evaluate the impact of 4 design parameters of an endodontic guide in the decision of practitioners
Methods: 16 guides were produced using an experience design. The guides are different combinations of extreme levels between defined minimum and maximum values. 4 parameters have been chosen which are Thickness, Internal Offset, Number of Support teeth and Present or Absent of Windows. The 16 guides were created from a maxillary study model combining a laboratory scan and a CBCT. The different guides were printed using a 3D printer and submitted to experts specializing in endodontics and having already used endodontic guides. The experts had to respond via a Likert scale to a question “Did you think that positioning of endodontic guide was appropriate?” ". The experts answered this question by giving a score between -2 and +2 with a graduation from 1 to 1. The guides were marked with an anonymity number, allowing the dentists' results to be compared in relation to the given parameters to each guide.
Results: The results of the experimental design showed that for guides having “Windows”, practitioners judged the guides not adjusted. We encounter the same situation with thick guides. Its 2 parameters (Windows and Thicknesses) would not have influenced the positioning of the guide, but they nevertheless significantly affected the evaluations of experienced practitioners. On the other hand, even if the internal shift appears to be a very influential parameter on positioning, its effect on practitioners' scores is not as pronounced.
Conclusions: These unexpected results could be explained by changes in thickness of the guide or by the presence of windows modifying the visual appearance of the guide in relation to the internal offset. These factors could potentially disrupt the practitioner's decision-making process, hence the importance of supplementing this visual examination with a scan using an Intra Oral Scanner in order to obtain a perfect vision of the positioning of the guide.