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In-vitro performance of CAD/CAM crowns with insufficient preparation design.
J Mech Behav Biomed Mater. 2019 02; 90:269-274.JM

Abstract

PURPOSE

To compare the debonding and fracture force of different CAD/CAM composite crowns with respect to the influence of water storage (0d vs. 90d/37 °C) and types of cementation (adhesive vs. self-adhesive).

METHODS

Extracted human molars were prepared with a worst-case preparation scenario providing a nonretentive design (height ~4 mm; angle ~15°) and reduced fitting (250 µm). After digitalization, 72 crowns (n = 8 per group; circular wall thickness 1.5 mm / occlusal thickness ~2.5 mm) were milled from the composites (CS, LU), one experimental composite (EX), a resin-infiltrated ceramic (VE), and a feldspar ceramic reference (VM). The crowns were adhesively bonded (Scotchbond Universal + Rely X Ultimate, 3M), and two groups (EX, VE) were additionally cemented with a self-adhesive cement (RelyX Unicem, 3M). After 90-d water storage, thermal cycling and mechanical loading (TCML) were performed. Restorations, which failed during storage or TCML, were analyzed using scanning electron microscopy, and surviving restorations were loaded to fracture. To evaluate storage effects, two materials (EX, LU) were investigated without water storage.

RESULTS

CS (7×) and LU (2×) exhibited debonding during 90-d storage. LU (5×) debonded during TCML. Cement remained on the inner sides of the crowns in all cases. EX and VE survived storage and TCML without failure or debonding. Two specimens of VM exhibited cracks after TCML. Fracture forces varied between 720 N and 2155 N. Solely the results between VE and VM were not significantly different (p = 0.204). Debonding effects due to water storage were material dependent. Fracture forces in tendency (p > 0.117) were higher for self-adhesive cementation.

CONCLUSIONS

Debonding and stability of CAD/CAM crowns were material dependent. Water storage affected debonding, and cementation marginally influenced performance and fracture force.

Authors+Show Affiliations

Department of Prosthetic Dentistry, UKR University Medical Center Regensburg, 93042 Regensburg, Germany.Department of Prosthetic Dentistry, UKR University Medical Center Regensburg, 93042 Regensburg, Germany.Department of Prosthetic Dentistry, UKR University Medical Center Regensburg, 93042 Regensburg, Germany.Department of Prosthetic Dentistry, UKR University Medical Center Regensburg, 93042 Regensburg, Germany. Electronic address: stephanie.krifka@ukr.de.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30388511

Citation

Rosentritt, Martin, et al. "In-vitro Performance of CAD/CAM Crowns With Insufficient Preparation Design." Journal of the Mechanical Behavior of Biomedical Materials, vol. 90, 2019, pp. 269-274.
Rosentritt M, Preis V, Behr M, et al. In-vitro performance of CAD/CAM crowns with insufficient preparation design. J Mech Behav Biomed Mater. 2019;90:269-274.
Rosentritt, M., Preis, V., Behr, M., & Krifka, S. (2019). In-vitro performance of CAD/CAM crowns with insufficient preparation design. Journal of the Mechanical Behavior of Biomedical Materials, 90, 269-274. https://doi.org/10.1016/j.jmbbm.2018.10.002
Rosentritt M, et al. In-vitro Performance of CAD/CAM Crowns With Insufficient Preparation Design. J Mech Behav Biomed Mater. 2019;90:269-274. PubMed PMID: 30388511.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - In-vitro performance of CAD/CAM crowns with insufficient preparation design. AU - Rosentritt,Martin, AU - Preis,Verena, AU - Behr,Michael, AU - Krifka,Stephanie, Y1 - 2018/10/03/ PY - 2018/07/04/received PY - 2018/10/01/revised PY - 2018/10/01/accepted PY - 2018/11/6/pubmed PY - 2020/2/11/medline PY - 2018/11/3/entrez KW - CAD/CAM KW - Ceramic KW - Composite KW - Fitting KW - TCML SP - 269 EP - 274 JF - Journal of the mechanical behavior of biomedical materials JO - J Mech Behav Biomed Mater VL - 90 N2 - PURPOSE: To compare the debonding and fracture force of different CAD/CAM composite crowns with respect to the influence of water storage (0d vs. 90d/37 °C) and types of cementation (adhesive vs. self-adhesive). METHODS: Extracted human molars were prepared with a worst-case preparation scenario providing a nonretentive design (height ~4 mm; angle ~15°) and reduced fitting (250 µm). After digitalization, 72 crowns (n = 8 per group; circular wall thickness 1.5 mm / occlusal thickness ~2.5 mm) were milled from the composites (CS, LU), one experimental composite (EX), a resin-infiltrated ceramic (VE), and a feldspar ceramic reference (VM). The crowns were adhesively bonded (Scotchbond Universal + Rely X Ultimate, 3M), and two groups (EX, VE) were additionally cemented with a self-adhesive cement (RelyX Unicem, 3M). After 90-d water storage, thermal cycling and mechanical loading (TCML) were performed. Restorations, which failed during storage or TCML, were analyzed using scanning electron microscopy, and surviving restorations were loaded to fracture. To evaluate storage effects, two materials (EX, LU) were investigated without water storage. RESULTS: CS (7×) and LU (2×) exhibited debonding during 90-d storage. LU (5×) debonded during TCML. Cement remained on the inner sides of the crowns in all cases. EX and VE survived storage and TCML without failure or debonding. Two specimens of VM exhibited cracks after TCML. Fracture forces varied between 720 N and 2155 N. Solely the results between VE and VM were not significantly different (p = 0.204). Debonding effects due to water storage were material dependent. Fracture forces in tendency (p > 0.117) were higher for self-adhesive cementation. CONCLUSIONS: Debonding and stability of CAD/CAM crowns were material dependent. Water storage affected debonding, and cementation marginally influenced performance and fracture force. SN - 1878-0180 UR - https://www.unboundmedicine.com/medline/citation/30388511/In_vitro_performance_of_CAD/CAM_crowns_with_insufficient_preparation_design_ DB - PRIME DP - Unbound Medicine ER -