TY - JOUR
T1 - Flexural strength of small connector designs of zirconia-based partial fixed dental prostheses
AU - Hamza, Tamer A.
AU - Attia, Mazen A.
AU - El-Hossary, Mohamed Mahmoud Khalil
AU - Mosleh, Ihab E.
AU - Shokry, Tamer E.
AU - Wee, Alvin G.
N1 - Publisher Copyright:
© 2016 Editorial Council for the Journal of Prosthetic Dentistry.
PY - 2016/2/1
Y1 - 2016/2/1
N2 - Statement of problem Partial fixed dental prostheses with a small connector size are required for optimal esthetics and limited interarch space; however, final strength is endangered. Purpose The purpose of this in vitro study was to evaluate the effect of different connector designs on the flexural strength of simulated 3-unit partial fixed dental prostheses made of yttria-stabilized tetragonal zirconia polycrystalline using computer-Aided design and computer-Aided manufacturing technology. Material and methods To simulate a 3-unit partial fixed dental prosthesis, 20 rectangular bar-shaped specimens were fabricated with dimensions of 4 ±0.05 mm (H)×4 ±0.05 mm (W)×30 0.5 mm (L). Each bar specimen had 2 constricted parts on both sides, representing the connector and defining a central pontic of 10 ±0.10 mm in length. The specimens were divided into 4 groups according to the connector diameter and design, as follows: SR: 2 mm (H)×3 mm (W) round 0.6 mm radius of curvature; SS: 2 mm (H)×3 mm (W) sharp 0.1 mm radius of curvature; CR: 3 mm (H)×3 mm (W) round 0.6 mm radius of curvature; and CS: 3 mm (H)×3 mm (W) sharp 0.1 mm radius of curvature. An additional 5 specimens were fabricated with no constriction and served as the control group. The specimens were subjected to a 3-point flexural strength test in a universal testing machine with a crosshead speed of 0.5 mm/min until failure. Scanning electron microscopic and photomicrograph images were used to examine the fracture surfaces. Two-way ANOVA and the Tukey-Kramer post hoc test were used to analyze the data (α=.05). Results The mean flexural strength for SR 2 mm (H)×3 mm (W) round 0.6 mm radius of curvature (583.6 ±49.7 MPa) was significantly higher than that of SS, which was 2 mm (H)×3 mm (W) sharp 0.1 mm radius of curvature (502.8 ±23.3 MPa). Similarly, the mean flexural strength for CR was 3 mm (H)×3 mm (W) round 0.6 mm radius of curvature (682.9 ±36.8), which was significantly higher than that of CC, 3 mm (H)×3 mm (W) sharp 0.1 mm radius of curvature (486.7 ±35.6 MPa). Conclusions The flexural strength of the yttria-stabilized tetragonal zirconia polycrystalline-based ceramics was affected by the connector dimension and design. The 2-round connector design was more able to withstand occlusal forces than the sharp design. The 3-connector design with a minimum cross section of 2×3 mm is recommended for anterior fixed dental prostheses, provided it has a round curvature.
AB - Statement of problem Partial fixed dental prostheses with a small connector size are required for optimal esthetics and limited interarch space; however, final strength is endangered. Purpose The purpose of this in vitro study was to evaluate the effect of different connector designs on the flexural strength of simulated 3-unit partial fixed dental prostheses made of yttria-stabilized tetragonal zirconia polycrystalline using computer-Aided design and computer-Aided manufacturing technology. Material and methods To simulate a 3-unit partial fixed dental prosthesis, 20 rectangular bar-shaped specimens were fabricated with dimensions of 4 ±0.05 mm (H)×4 ±0.05 mm (W)×30 0.5 mm (L). Each bar specimen had 2 constricted parts on both sides, representing the connector and defining a central pontic of 10 ±0.10 mm in length. The specimens were divided into 4 groups according to the connector diameter and design, as follows: SR: 2 mm (H)×3 mm (W) round 0.6 mm radius of curvature; SS: 2 mm (H)×3 mm (W) sharp 0.1 mm radius of curvature; CR: 3 mm (H)×3 mm (W) round 0.6 mm radius of curvature; and CS: 3 mm (H)×3 mm (W) sharp 0.1 mm radius of curvature. An additional 5 specimens were fabricated with no constriction and served as the control group. The specimens were subjected to a 3-point flexural strength test in a universal testing machine with a crosshead speed of 0.5 mm/min until failure. Scanning electron microscopic and photomicrograph images were used to examine the fracture surfaces. Two-way ANOVA and the Tukey-Kramer post hoc test were used to analyze the data (α=.05). Results The mean flexural strength for SR 2 mm (H)×3 mm (W) round 0.6 mm radius of curvature (583.6 ±49.7 MPa) was significantly higher than that of SS, which was 2 mm (H)×3 mm (W) sharp 0.1 mm radius of curvature (502.8 ±23.3 MPa). Similarly, the mean flexural strength for CR was 3 mm (H)×3 mm (W) round 0.6 mm radius of curvature (682.9 ±36.8), which was significantly higher than that of CC, 3 mm (H)×3 mm (W) sharp 0.1 mm radius of curvature (486.7 ±35.6 MPa). Conclusions The flexural strength of the yttria-stabilized tetragonal zirconia polycrystalline-based ceramics was affected by the connector dimension and design. The 2-round connector design was more able to withstand occlusal forces than the sharp design. The 3-connector design with a minimum cross section of 2×3 mm is recommended for anterior fixed dental prostheses, provided it has a round curvature.
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U2 - 10.1016/j.prosdent.2015.06.022
DO - 10.1016/j.prosdent.2015.06.022
M3 - Article
C2 - 26547519
AN - SCOPUS:84958280744
SN - 0022-3913
VL - 115
SP - 224
EP - 229
JO - Journal of Prosthetic Dentistry
JF - Journal of Prosthetic Dentistry
IS - 2
ER -