Influence of occlusal thickness on the fracture resistance of chairside milled lithium disilicate posterior full-coverage single-unit prostheses containing virgilite: A comparative in vitro study.
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BORIS DOI
Publisher DOI
PubMed ID
38790151
Description
PURPOSE
To evaluate the fracture resistance of chairside computer-aided design and computer-aided manufacturing (CAD-CAM) lithium disilicate mandibular posterior crowns with virgilite of different occlusal thicknesses and compare them to traditional lithium disilicate crowns.
MATERIALS AND METHODS
Seventy-five chairside CAD-CAM crowns were fabricated for mandibular right first molars, 60 from novel lithium disilicate with virgilite (CEREC Tessera, Dentsply Sirona), and 15 from traditional lithium disilicate (e.max CAD, Ivoclar Vivadent). These crowns were distributed across five groups based on occlusal thickness and material: Group 1 featured CEREC Tessera crowns with 0.8 mm thickness, Group 2 had 1.0 mm thickness, Group 3 had 1.2 mm thickness, Group 4 with 1.5 mm thickness, and Group 5 included e.max CAD crowns with 1.0 mm thickness. These crowns were luted onto 3D-printed resin dies using Multilink Automix resin cement (Ivoclar Vivadent). Subsequently, they underwent cyclic loading (2,000,000 cycles at 1 Hz with a 275 N force) and loading until fracture. Scanning electron microscopy (SEM) assessed the fractured specimens. Statistical analysis involved one-way ANOVA and the Kruskal-Wallis Test (α = 0.05).
RESULTS
Fracture resistance varied significantly (<0.001) across mandibular molar crowns fabricated from chairside CAD-CAM lithium disilicate containing virgilite, particularly between crowns with 0.8 mm and those with 1.2 and 1.5 mm occlusal thickness. However, no significant differences were found when comparing crowns with 1, 1.2, and 1.5 mm thicknesses. CEREC Tessera crowns with 1.5 mm thickness exhibited the highest resistance (2119 N/mm2), followed by those with 1.2 mm (1982 N/mm2), 1.0 mm (1763 N/mm2), and 0.8 mm (1144 N/mm2) thickness, whereas e.max CAD crowns with 1.0 mm occlusal thickness displayed the lowest resistance (814 N/mm2).
CONCLUSIONS
The relationship between thickness and fracture resistance in the virgilite lithium disilicate full-coverage crowns was directly proportional, indicating that increased thickness corresponded to higher fracture resistance. No significant differences were noted among crowns with thicknesses ranging from 1 to 1.5 mm. This novel ceramic exhibited superior fracture resistance compared to traditional lithium disilicate.
To evaluate the fracture resistance of chairside computer-aided design and computer-aided manufacturing (CAD-CAM) lithium disilicate mandibular posterior crowns with virgilite of different occlusal thicknesses and compare them to traditional lithium disilicate crowns.
MATERIALS AND METHODS
Seventy-five chairside CAD-CAM crowns were fabricated for mandibular right first molars, 60 from novel lithium disilicate with virgilite (CEREC Tessera, Dentsply Sirona), and 15 from traditional lithium disilicate (e.max CAD, Ivoclar Vivadent). These crowns were distributed across five groups based on occlusal thickness and material: Group 1 featured CEREC Tessera crowns with 0.8 mm thickness, Group 2 had 1.0 mm thickness, Group 3 had 1.2 mm thickness, Group 4 with 1.5 mm thickness, and Group 5 included e.max CAD crowns with 1.0 mm thickness. These crowns were luted onto 3D-printed resin dies using Multilink Automix resin cement (Ivoclar Vivadent). Subsequently, they underwent cyclic loading (2,000,000 cycles at 1 Hz with a 275 N force) and loading until fracture. Scanning electron microscopy (SEM) assessed the fractured specimens. Statistical analysis involved one-way ANOVA and the Kruskal-Wallis Test (α = 0.05).
RESULTS
Fracture resistance varied significantly (<0.001) across mandibular molar crowns fabricated from chairside CAD-CAM lithium disilicate containing virgilite, particularly between crowns with 0.8 mm and those with 1.2 and 1.5 mm occlusal thickness. However, no significant differences were found when comparing crowns with 1, 1.2, and 1.5 mm thicknesses. CEREC Tessera crowns with 1.5 mm thickness exhibited the highest resistance (2119 N/mm2), followed by those with 1.2 mm (1982 N/mm2), 1.0 mm (1763 N/mm2), and 0.8 mm (1144 N/mm2) thickness, whereas e.max CAD crowns with 1.0 mm occlusal thickness displayed the lowest resistance (814 N/mm2).
CONCLUSIONS
The relationship between thickness and fracture resistance in the virgilite lithium disilicate full-coverage crowns was directly proportional, indicating that increased thickness corresponded to higher fracture resistance. No significant differences were noted among crowns with thicknesses ranging from 1 to 1.5 mm. This novel ceramic exhibited superior fracture resistance compared to traditional lithium disilicate.
Date of Publication
2025-10
Publication Type
Article
Keyword(s)
CAD‐CAM systems computer‐aided design dental crowns dental materials dental occlusion
Language(s)
en
Contributor(s)
Jurado, Carlos A | |
Davila, Christian Edgar | |
Davila, Alexandra | |
Hernandez, Alfredo I | |
Odagiri, Yukari | |
Lee, Damian |
Series
Journal of prosthodontics
Publisher
Wiley
ISSN
1532-849X
Access(Rights)
open.access