The effect of two preparation designs on the fracture resistance and marginal adaptation of two types of ceramic crowns using CAD/CAM technology (In vitro study).
BMC Oral Health
; 24(1): 1065, 2024 Sep 11.
Article
in En
| MEDLINE
| ID: mdl-39261857
ABSTRACT
BACKGROUND:
Recently, prosthodontic approaches involve more conservative procedures that include less invasive finish line preparations that use less ceramic thickness. AIM OF THE STUDY This in vitro study aimed to evaluate the effect of vertical preparation and modified vertical preparation designs on the marginal adaptation and fracture resistance of two types of ceramic crowns using CAD/CAM technology. MATERIALS ANDMETHODS:
Two typodont maxillary first premolars were embedded in acrylic resin. Forty positive replicas of epoxy resin dies were used that were divided into two groups depending on the preparation design (n = 20); Group V (Vertical) dies with feather edge finish line and Group MV (Modified vertical) dies with feather edge finish line, where a reverse shoulder of 1 mm depth was placed on the buccal surface 1.5 mm from the occlusal surface. Each group was further subdivided into two subgroups according to the type of ceramic material (n = 10) Subgroup Va and subgroup MVa for lithium disilicate (e.max CAD) and subgroup Vb and subgroup MVb for zirconia (zolid ht+). Crown restorations were made with CAD-CAM technology. The marginal adaptation was assessed using a stereomicroscope both prior to cementation and after cementation and aging. Fracture resistance was tested with a universal testing machine, and the data were statistically analyzed.RESULTS:
Marginal adaptation showed no significant differences between subgroups before or after cementation and aging. Three-way ANOVA indicated that preparation design (p = 0.516) and material (p = 0.269) had no significant effect, but cementation had a significant effect (p < 0.0001) on the marginal adaptation. According to two-way ANOVA test, Subgroup (MVb) showed the highest result followed by subgroup (Vb) and subgroub (MVa) and the least was subgroub (Va). Fracture modes showed no significant differences among the subgroups (p = 0.982).CONCLUSIONS:
Marginal adaptation of lithium disilicate and zirconia crowns remained clinically acceptable regardless of preparation design. While the modified vertical preparation with a reverse shoulder notably enhanced the fracture resistance of both materials, with zirconia demonstrating superior fracture resistance compared to lithium disilicate with average values exceeding premolar biting force.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Zirconium
/
Ceramics
/
Dental Prosthesis Design
/
Computer-Aided Design
/
Dental Marginal Adaptation
/
Crowns
/
Dental Porcelain
/
Dental Stress Analysis
Limits:
Humans
Language:
En
Journal:
BMC Oral Health
Journal subject:
ODONTOLOGIA
Year:
2024
Document type:
Article
Affiliation country:
Egypt
Country of publication:
United kingdom