Sauberkeit von Milchzahnwurzelkanälen nach Präparation mit unterschiedlichen Nickel-Titan-Systemen - Eine REM-Studie
von Kieu Minh Phan
Datum der mündl. Prüfung:2023-03-02
Erschienen:2023-02-23
Betreuer:Prof. Dr. Michael Hülsmann
Gutachter:Prof. Dr. Michael Hülsmann
Gutachter:Prof. Dr. Ralf Bürgers
Dateien
Name:Phan_KieuMinh eDiss.pdf
Size:1.35Mb
Format:PDF
Description:Dissertation
Zusammenfassung
Englisch
Introduction: In the present in-vitro study the cleaning efficacy of two rotary Ni-Ti preparation systems was examined on the root canal walls of primary molars. The aim was to compare the different rotary systems with the same irrigation amount and concentration and to find out, which cleans the root canal more effective. Material and methods: 46 extracted primary molars with three to four root canals were accessed and divided into 23 matched pairs according to the same number, similar shape, length and curvature of the roots based on a three-dimensional micro-CT analysis (Bruker SkyScan 1272, Bruker AXS, Karlsruhe) (resolution: 29 µm). The matched pairs were randomly assigned to two comparable groups (n=23). One group was instrumented using the SAF system, which is based on a one-file technique, continuous irrigation with NaOCl (1 %) for 3 min per root canal and a flow of 4 ml/min. The other group was prepared using Mtwo rotary files, which is based on a single-length-technique. A total of five files were used and after each instrument a manual rinse with 2 ml NaOCl (1 %) was performed, therefore both experimental groups had a total amount of 12 ml of 1 % NaOCl irrigant and a final rinse with 2 ml of 10 % citric acid per root canal. Finally, the roots were split longitudinally and the exposed root canal walls were observed under the SEM (field emission scanning electron microscope Ultra plus, Fa. Zeiss, Oberkochen) and digital images were taken of two randomly selected root canal areas of the apical und coronal part. The cleanliness of the root canal walls was assessed by two blinded examiners on the basis of a total of 326 SEM images at 1,000x magnification using a four-stage score evaluation system (grade 1: 0–24 % surface covered by smear layer, grade 2: 25–49 %, grade 3: 50–74 %, grade 4: 75–100 %). The statistical evaluation was performed using the Mann-Whitney U-test and the Bonferroni correction (p<0.05). Results: The comparison of SAF and Mtwo shows no significant difference in the cleaning effect (p = 0.95). Comparing the coronal versus the apical cleaning, neither Mtwo (0.09) nor SAF (0.08) showed significant differences. The comparison of the coronal versus the apical part of the root canals revealed a better cleanliness in the coronal area.
Keywords: cleaning efficacy; root canal walls; primary molars; SAF; Mtwo