Application of an Endodontic Static Guide in Fiber Post Removal from a Compromised Tooth

Table 1

Summary of possible sources of error in endodontic static guide construction and recommended solutions.

Sources of error	Recommendation
CBCT acquisition (DICOM format)	(1) Smallest possible field of view and ideally high resolution are required; (2) Improve the quality of the CBCT image and enhance the diagnostic capacity by adjusting the acquisition settings, ensuring patient stability, and utilizing appropriate software for acquiring and running the images; (3) Apply artifact reduction filters to preserve the details
Digital surface scan (STL format)	(1) Directly via an intraoral scanner; (2) Digitizing a plaster cast using a laboratory scanner; (3) No clinical alterations to the position and morphology of the teeth should be made after the CBCT and intraoral scanning process; (4) New scans must be performed if the DICOM and STL files are of poor quality
Digital planning software	(1) Ensure that the software accurately synchronizes the DICOM file with the STL file using identifiable landmarks on the crown surfaces of the two files; (2) Drill must be placed in the center of the root canal so that the tip reaches the end of the fiber post
3D printing	(1) Transform the STL file into a sequence of numerous layers or slices. Increase the reliability of the printed guide by reducing the thickness of the slices; (2) Precise curing is essential to maintain the dimensional stability of the guide; (3) Print endodontic static guides using light-curing liquid resin and direct light processing technology; (4) Adjust printer settings based on manufacturer recommendations
Clinical application	(1) Ensure precise positioning of the guide on the teeth. Verification windows should be used in the guide’s design to visualize the correct placement; (2) Achieve greater occlusal surface adaptation to increase guide stability and reduce the risk of deviation; (3) Rocking movements or improper fit of the guide can jeopardize the accuracy of the treatment (fixative pins can be used, especially in the posterior regions, due to the displacing forces of the tongue and muscles); (4) Use metal sleeves instead of plastic sleeves; (5) Set the minimum height of the sleeve at 5 mm. (The higher the height of the sleeve, the more contact area it has with the drill, and it can perform the guiding process with greater accuracy); (6) Ensure that the metal sleeve is inserted properly into the guide template; (7) Adaptation of the drill with the intended sleeve should be checked; (8) A drill with a consistent diameter throughout all active areas in contact with the sleeve is recommended to reduce errors; (9) The drill being used can withstand bending