Comparative Assesment of Fracture Resistance in Endodontically‐Treated Maxillary Premolars With Different Restoration Techniques: Direct Resin Composite and Endocrown

<b>Purpose:</b> Evaluate fracture strength in endodontically-treated maxillary premolar teeth, restored using direct resin composite or endocrowns, considering various cavity dimensions. <b>Method and Materials:</b> Forty extracted human maxillary premolar teeth were subjected to disto-occlusal and access cavity preparation, and subsequently divided based on the cavity preparation wall thickness into 2 mm and 3 mm groups. Further, teeth were subdivided according to restoration type into: (1) direct composite, no cusp coverage; (2) direct composite, palatal cusp coverage; (3) direct composite, full-cusp coverage; and (4) lithium disilicate endocrown, full-cusp coverage (<i>n</i> = 5). Statistical analyses included the Shapiro-Wilk test, two-way ANOVA, and Tukey's post hoc test, with a significance level set at 0.05. <b>Results:</b> Notable differences in fracture strength were observed between groups. The lowest and highest values were associated with the direct resin composite group (without cusp coverage) and the endocrown group (with full-cusp coverage), respectively. Wall thickness (2 versus 3 mm) did not significantly impact results. <b>Conclusion:</b> In endodontically-treated maxillary premolar teeth, direct restoration with at least palatal cusp coverage or full-cusp coverage could be as successful as endocrown restoration.