Examining the adaptation of modified endocrowns prepared with CAD-CAM in maxillary and mandibular molars: A microcomputed tomography study

Statement of problem. Endocrowns have been reported to be successful restorations for endodontically treated molars. However, comparisons between maxillary and mandibular molars, with different pulp chamber configurations are lacking. Information on the influence of venting on the adaptation of endocrowns is also lacking. Purpose. The purpose of this in vitro study was to evaluate the adaptation of endocrowns in maxillary and mandibular molars by means of microcomputed tomography (mCT). Material and methods. Mandibular and maxillary first molars were divided into 4 groups (n=10): ManE: mandibular endocrown; ModManE: modified mandibular endocrown; MaxE: maxillary endocrown; and ModMaxE: modified maxillary endocrown. Endocrowns were produced by using computer-aided design and computer-aided manufacture (CAD-CAM). Modification was carried out on the part of the endocrown that extended into the pulp chamber by preparing vents. The specimens were cemented and scanned by using mCT, the images reconstructed, and the internal and marginal adaptation examined. Statistical analyses were performed by using a 3way ANOVA, 2-way ANOVA, and the independent samples t test (alpha=.05). Results. ManE displayed better mean +/- standard deviation internal adaptation (182 +/- 59 mm) than MaxE (215 +/- 55 mm) (P<.01). Regardless of the groups, the pulpal floor was the area with the poorest fit (P<.001). The marginal gap of mandibular molars (91 +/- 20 mm) was lower than that of maxillary molars (110 +/- 26 mm) (P<.05). The effect of modifying endocrowns on the marginal gap was not found to be statistically significant (P>.05). Conclusions. Internal and marginal adaptation of endocrowns differ between maxillary and mandibular molars.