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

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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.

Section snippets

Material and methods

After approval of the research protocol by the local ethics board of Ondokuz Mayıs University (KAEK-B.30.2.ODM.0.20.08/789), 20 maxillary and 20 mandibular first molars were selected. The inclusion criteria were a developed root structure, no caries or visible fracture lines, and similar buccolingual and mesiodistal dimensions (maximum difference of 10%), measured with digital calipers (47252; Cen-tech). The ages of the donor patients were unknown. After removal of the soft tissue residuals on

Results

Three-way ANOVA showed that the internal discrepancy values were significantly affected by modification (P=.043) and tooth type (P<.001). Significant interactions were found among the selected sections, modification, and tooth type (P=.009) (Table 1). The mean ±standard deviation internal discrepancy values of ManE (182 ±59 μm) were lower than those of MaxE (215 ±55 μm) (P<.01). Moreover, the internal gap was found to be 167 ±23 μm in ModManE and 206 ±40 μm in ModMaxE (P<.01). No statistically

Discussion

The null hypothesis was partially accepted because, while mandibular endocrown showed better internal and marginal discrepancy than maxillary molar endocrowns, no difference was found between restorations with or without vents. Endocrowns are becoming popular for the restoration of severely damaged endodontically treated teeth.6 Marginal and internal adaptation are both important parameters that may affect the success of these restorations.8 A consensus or a standard for measuring the

Conclusions

Based on the findings of this in vitro study, the following conclusions were drawn:

  • 1.

    Variations in the cross-sectional morphology of the pulpal chambers of maxillary and mandibular molars affected the adaptation of endocrowns prepared by using CAD-CAM.

  • 2.

    Modifications to the retentive parts of endocrowns do not affect the adaptation of the restoration.

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    • Cited by (0)

    Supported by Ondokuz Mayıs University Research Fund, grant #1904.17.020.

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