ABSTRACT
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 (µCT). 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 µCT, the images reconstructed, and the internal and marginal adaptation examined. Statistical analyses were performed by using a 3-way ANOVA, 2-way ANOVA, and the independent samples t test (α=.05). RESULTS: ManE displayed better mean ±standard deviation internal adaptation (182 ±59 µm) than MaxE (215 ±55 µm) (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 µm) was lower than that of maxillary molars (110 ±26 µm) (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.
Subject(s)
Crowns , Dental Prosthesis Design , Computer-Aided Design , Dental Porcelain , Dental Prosthesis Design/methods , Materials Testing , Molar/diagnostic imaging , X-Ray MicrotomographyABSTRACT
The aim of this study was to investigate the effects of different post and core systems, CAD/CAM crown placement on fracture strength of endodontically treated mandibular premolar teeth. One hundred forty single-rooted premolar teeth were randomly divided into a control group and six experimental groups as follows: control group (Group 1); FiberSite post luting with Clearfil DC Core Plus (Group 2); RelyX Fiber post luting and core build up with Clearfil DC Core Plus (Group 3); RelyX Fiber post luting with Clearfil DC Core Plus and core build up with Filtek Bulk Fill Posterior (Group 4); specimens that received CAD/CAM crowns after the same procedures performed in Groups 2, 3, and 4, respectively (Groups 5, 6, and 7). Fracture strength tests were performed, and the failure modes were recorded. Data were statistically analyzed using one-way ANOVA and post hoc Tukey tests. The highest fracture resistance was observed in the control group and among the experimental groups in Group 4. Groups 3 and 5 showed similar fracture resistance followed by Group 2. The lowest fracture resistances were seen in the samples of Groups 6 and 7. While the fracture strength of Group 2 increased after the crown placement (Group 5), the fracture strength of Group 3 and Group 4 decreased (P < 0.05). While the specimens in Groups 1, 2, 3, and 4 predominantly showed favorable failure, unfavorable failure was more frequent in Groups 5, 6, and 7.
