RESUMO
Introduction: The ability of the temporary filling to seal endodontic access cavities may be crucial for the success of endodontic treatment. Numerous in vitro studies have investigated the sealability of the temporary fillings used in endodontic treatments. However, in vitro sealability studies have been criticized for their inconsistent results and questionable clinical relevance. Some journals have imposed moratoriums on publishing such studies to encourage researchers to test their validity and clinical relevance. Since the implementation of this moratorium, little progress has been made in this field. To further encourage researchers to investigate the reliability of these studies, this review presents an overview of the methodologies of studies that examine the ability of temporary filling materials to seal the endodontic access cavity in vitro and discusses the criticisms of these studies in detail. Materials and Methods: PubMed, Scopus, and Embase electronic databases were searched to identify studies that tested in vitro the ability of temporary filling materials to seal endodontic access cavities. Only original articles published in English between 01/01/1970 and 28/02/2022 were included. Results: The search yielded 551 results. After removing duplicates and excluding studies that did not meet the inclusion criteria, 94 studies were included in this review. Conclusion: Although clinical studies may be the best way to test the performance of temporary fillings, the ethical importance of conducting preliminary in vitro studies is undeniable. It seems that questioning the reliability of in vitro sealability studies is not based on sufficient scientific evidence and that the inconsistencies in the results of these studies may be due to differences in the methodological and clinically relevant variables between them, rather than due to their unreliability.
RESUMO
PURPOSE: This study had two aims: (1) to compare the retention of a flexible directly placed fiber-bundle dowel system with that of a rigid prefabricated fiber-reinforced composite (FRC) dowel system, and (2) to determine the effect of decreasing the volume of luting cement around the flexible fiber-bundle dowels on the axial retention of the restorations. MATERIALS AND METHODS: Single-canal premolars (n = 36) were decoronated, cleaned, shaped, and prepared for both flexible and rigid dowels to a depth of 10 mm using a size 2 drill. The roots were then randomly allocated into three groups: Ia, Ib, and II (n = 12). Flexible fiber-bundle dowels were placed in groups Ia and Ib. These were available in three fiber-bundle diameters: small (0.9 mm), medium (1.2 mm), and large (1.5 mm). These bundles were luted in the root canals with Variolink II. The differences between Ia and Ib were in the ratio of the volume of fiber-bundles to the volume of luting cement and in the mode of application. Medium fiber-bundles were placed to the end of the preparation in groups Ia and Ib; however, in group Ia, a small diameter auxiliary bundle was placed, whereas in group Ib, a large-diameter auxiliary bundle was cut axially into strips of circa 0.2-mm thickness before being sequentially overlapped in placement. Roots in group II were restored with size 2 rigid prefabricated fiber dowels and luted with the light-cured cement provided by the manufacturer. After 24 hours of storage, axial tensile forces were applied to all luted dowels progressively to failure at 0.5 mm/min. Data were analyzed using a one-way analysis of variance (ANOVA) and the Bonferonni test. RESULTS: The mean axial resistance forces (standard deviation [SD]) for groups Ia, Ib, and II were not statistically different at 166 (49), 157 (36), and 151 (44) N, respectively (p > 0.05). CONCLUSIONS: There was no significant difference between the retention of the flexible fiber-bundle dowel system and that of the rigid prefabricated fiber dowel system. Decreasing the volume of luting cement around the flexible dowels did not have a significant effect on the axial retention of the restorations.
