The Effect of Cement Space Parameters on the Marginal Adaptation of Milled Endocrowns: An In Vitro Study

Abstract

Background Cement film space plays a significant role in achieving good adaptation of indirect restorations. The objective of this study is to investigate the effect of cement space parameters on the marginal adaptation of computer-aided design (CAD)/computer-assisted manufacturing (CAM) endocrowns. Methodology The coronal part of 10 freshly extracted human mandibular molars was reduced to a level of 1.5 mm above the cementoenamel junction (CEJ); then, root canal treatment was performed. On each tooth, four lithium disilicate endocrowns with different cement space parameters (40, 80, 120, and 160 µm) were designed and fabricated using CAD/CAM. Endocrowns were seated to their prepared teeth, and the vertical marginal gap was measured in 20 equidistant points for each endocrown using a stereomicroscope on 90× magnification. The mean marginal gaps of the four groups were compared using a one-way analysis of variance (ANOVA) and the Tukey honestly significant difference (HSD) test considering p<0.05 as the cutoff for statistical significance. Results The mean marginal gap of the 40 µm, 80 µm, 120 µm, and 160 µm groups were 46.25±21.20 µm, 21.75±11.10 µm, 15.94±06.62 µm, and 13.10±07.08 µm, respectively. One-way ANOVA showed a significant difference in the marginal gaps between groups (p<0.001). The Tukey post hoc test showed a statistically significant mean difference between 40 µm and each of the other three groups (p<0.001). Conclusion The cement space parameter variation affects the marginal adaptation of endocrowns. The cement space of 40 µm resulted in a higher marginal gap than cement spaces of 80, 120, and 160 µm.

A Comparative Analysis of Marginal Adaptation Values between Lithium Disilicate Glass Ceramics and Zirconia-Reinforced Lithium Silicate Endocrowns: A Systematic Review of In Vitro Studies

“…All included studies were in vitro studies [ 12 – 28 ]. The highest number of publications, 7 studies (41%), was from the year 2023 [ 12 – 15 , 19 , 20 , 22 ], followed by years between 2020 and 2022, with 6 studies (35%) [ 20 , 21 , 25 – 28 ]. Fourteen (76%) studies reported using natural teeth [ 12 – 15 , 17 – 23 , 25 – 27 ], 12 studies (71%) were for mandibular arches [ 13 – 17 , 19 – 20 , 22 – 25 , 27 ], and 11 studies (65%) were for molars [ 13 – 16 , 19 , 22 – 25 , 27 , 28 ].…”

“…The highest number of publications, 7 studies (41%), was from the year 2023 [ 12 – 15 , 19 , 20 , 22 ], followed by years between 2020 and 2022, with 6 studies (35%) [ 20 , 21 , 25 – 28 ]. Fourteen (76%) studies reported using natural teeth [ 12 – 15 , 17 – 23 , 25 – 27 ], 12 studies (71%) were for mandibular arches [ 13 – 17 , 19 – 20 , 22 – 25 , 27 ], and 11 studies (65%) were for molars [ 13 – 16 , 19 , 22 – 25 , 27 , 28 ]. LDGC and zirconia were the most common all-ceramic materials used for endocrown constructions, with 35% and 30%, respectively, and either alone or in comparisons with other all-ceramic materials.…”

“…Marginal adaptation, defined as the gap between the finish line and the prostheses margin, is measured as one of the main criteria affecting the long-term prognosis of ceramic CAD/CAM prostheses [ 47 ]. Presence of a significant marginal gap between the tooth and the endocrown luting material will be visible to the oral location, resulting in luting dissolution and microleakage, leading to irritation of the gingival tissues, secondary caries, and finally endocrown failure [ 15 – 17 , 21 – 23 , 26 – 28 ]. The assessment of the marginal adaptation of prostheses is regularly accomplished using a simple technique with a digital microscope [ 19 – 21 ], stereomicroscope [ 12 – 15 , 17 , 18 ], or more advanced systems, such as SEM [ 26 , 27 ] and microcomputed tomography [ 22 – 25 ], as shown in Table 1 .…”

“…Presence of a significant marginal gap between the tooth and the endocrown luting material will be visible to the oral location, resulting in luting dissolution and microleakage, leading to irritation of the gingival tissues, secondary caries, and finally endocrown failure [ 15 – 17 , 21 – 23 , 26 – 28 ]. The assessment of the marginal adaptation of prostheses is regularly accomplished using a simple technique with a digital microscope [ 19 – 21 ], stereomicroscope [ 12 – 15 , 17 , 18 ], or more advanced systems, such as SEM [ 26 , 27 ] and microcomputed tomography [ 22 – 25 ], as shown in Table 1 . All systems used for endocrown marginal adaptation showed a high degree of accuracy and usually used the micrometer for assessments.…”

“…Various ceramic systems are used for endocrown fabrications, such as feldspathic ceramics [ 26 , 27 ], lithium disilicate glass ceramics (LDGC) [ 13 , 15 – 19 , 22 , 23 , 25 ], and different types of zirconia [ 13 , 14 , 21 ], which have high mechanical strength and can be acid-etched. Zirconia and LDGC are considered the best choices owing to their mechanical and aesthetic features, including good anti-abrasion, anti-aging, and anti-corrosion properties, translucency, and biocompatibility with natural teeth.…”