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Objective: The purpose of this experimental in vitro study was to assess the effect of having one or two intact axial walls on the improvement of the fracture resistance, and marginal and internal adaptation of computer-aided design/computer-aided manufacturer fabricated ceramic endocrowns.Materials and Methods: Thirty-six endodontically treated mandibular molars were divided into three groups (n = 12). Group A, represented teeth that all of their axial walls were reduced till they all had 3 mm height. In group B, the buccal wall had 5 mm height and the others were reduced to 3 mm. Specimens of the group C had 5-mm-height buccal and one 5 mm-height proximal wall, with all other walls of 3 mm height. All teeth were scanned using intraoral scanner, and endocrowns were milled from zirconia lithium silicate ceramics blocks. The marginal and internal discrepancy of restorations were evaluated with the replica technique. Fracture resistance was also measured after cementation and modes of failure were observed. One-way analysis of variance and Tukey HSD multiple comparisons were used to analyze the data (α = .5).Results: Significant differences were observed within the groups in terms of the axial discrepancy (p = .022); group A had significantly higher amounts of axial discrepancy compared to group B (p = .001) and group C (p = .003). Preservation of the intact axial walls did not result in a statistically significant decrease in marginal (p = .21) and pulpal (p = .31) discrepancy values. Also, concerning the fracture resistance no significant difference was observed among the groups (p = .51). Conclusion:Preservation of at least one of the axial walls could reduce the amount of the axial discrepancy and, therefore, improves the adaptation of the restoration.However, based on this study, it did not improve fracture resistance.

Central giant cell granuloma (CGCG) is a benign non-neoplastic intraosseous lesion mainly found in the anterior mandible. It is characterized by multinucleated giant cells, representing osteoclasts or macrophages. Central odontogenic fibroma (COF) is an uncommon benign lesion of the jaws. It originates from the odontogenic ectomesenchyme. In rare cases, COF may accompany a CGCG. To date, 49 cases of COF accompanied by CGCG-like lesions have been reported in the literature. In this paper, we present another case of COF-CGCG in a 46-year-old female. The lesion was located in the posterior mandible. Excisional biopsy was carried out, and histopathological analysis revealed multinucleated giant cells with numerous strands of odontogenic epithelium. A literature review of previously reported cases was also performed.

Background and Aim: Marginal adaptation has a significant role in the success and longevity of indirect restorations. This experimental study compared the effect of intraoral and extraoral scanning on the marginal adaptation of the crowns which was made using the CEREC AC system. Materials and Methods: A Typodont maxillary first molar was prepared and served as the master die for an all-ceramic restoration. In the first group, the model was scanned ten times directly by the intraoral scanner. In the second group, ten conventional impressions were made from Typodont, and the extraoral scanner scanned the resulting gypsum casts. The data was used to design and build crowns from IPS e.max CAD blocks. The crowns were placed on the prepared tooth, and the marginal gap was measured at 16 points by a stereomicroscope at ×35 magnification. Collected data were analyzed using t-test. Results: The mean marginal gap for intraoral and extraoral groups were 74.83 ± 10.07 μm and 102.56 ± 6.89 μm respectively. The gap was significantly less in the intraoral group (P-value = 0.001). Conclusion: Marginal adaptation was clinically acceptable in both groups, although the results of intraoral scanning showed significantly lower gap than extraoral scanning.