Comparação de pastas a base de óxido de zinco e eugenol para obturação de molares decíduos: estudo in vitro com protótipos

Abstract

Endodontic treatment of primary teeth with pulp involvement aims to maintain their function and the integrity of the dental arch until physiological exfoliation. One of the steps of this treatment involves filling the root canals with a resorbable paste. The quality of root canal filling remains a challenge in pediatric dental practice. An ideal filling requires hermetic sealing, since the presence of internal voids can lead to the proliferation of microorganisms and treatment failures. This in vitro study aimed to compare the quality of root canal fillings in prototypes of primary molars using three zinc oxide and eugenol-based pastes (ZOE, Endoflas®, and an experimental paste similar to Endoflas®), associated with two filling techniques (lentulo and syringe), through volumetric analysis performed using micro-computed tomography (Micro-CT). Thirty standardized 3D-printed prototypes of mandibular second primary molars were used. After standardized instrumentation, the prototypes were scanned by Micro-CT to obtain the baseline images. Subsequently, the canals were filled using different combinations of paste and technique. The prototypes were rescanned by Micro-CT to measure the percentage of filled canal volume, the total number of internal voids, the percentage of voids, and the percentage of large internal voids (defects). Data were analyzed using the IBM SPSS Statistics 26.0 with Mann-Whitney and Kruskal-Wallis tests (p<0.05). The results showed no statistically significant differences among the groups for any of the variables analyzed (p>0.05). All combinations presented mean percentages of filled canals above 80%. The ZOE paste showed the highest number (34.30 ±18.09) and percentage (31.66 ±19.25) of internal voids, while the experimental paste showed the lowest values for these outcomes (17.50 ±7.63; p=0.106 and 21.40 ±10.34; p=0.689). Regarding the technique, the syringe showed a higher percentage of filled canals (89.72 ±10.36) than lentulo (83.20 ±18.76; p=0.461); however, lentulo showed a lower percentage of large internal voids (66.19 ±14.41) than the syringe (78.33 ±19.27; p=0.074). It is concluded that, despite the observed variations, the quality of root canal filling was similar among the tested pastes and between the evaluated techniques, with no combination being statistically superior.