Limits...
The effect of zirconia framework design on the failure of all-ceramic crown under static loading.

Urapepon S, Taenguthai P - J Adv Prosthodont (2015)

Bottom Line: The mean and standard deviations of the failure load were 1,170.1 ± 90.9 N for EV design and 1,450.4 ± 175.7 N for CB design.A significant difference in the compressive failure load was found (P<.05).For the failure characteristic, the EV design was found only cohesive failures within veneering porcelain, while the CB design found more failures through the zirconia framework (8 from 10 samples).

View Article: PubMed Central - PubMed

Affiliation: Prosthodontics Department, Faculty of Dentistry, Mahidol University, Bangkok, Thailand.

ABSTRACT

Purpose: This in vitro study aimed to compare the failure load and failure characteristics of two different zirconia framework designs of premolar crowns when subjected to static loading.

Materials and methods: Two types of zirconia frameworks, conventional 0.5 mm even thickness framework design (EV) and 0.8 mm cutback of full contour crown anatomy design (CB), were made for 10 samples each. The veneer porcelain was added on under polycarbonate shell crown made by vacuum of full contour crown to obtain the same total thickness of the experiment crowns. The crowns were cemented onto the Cobalt-Chromium die. The dies were tilted 45 degrees from the vertical plane to obtain the shear force to the cusp when loading. All crowns were loaded at the lingual incline of the buccal cusp until fracture using a universal testing machine with cross-head speed 0.5 mm/min. The load to fracture values (N) was recorded and statistically analyzed by independent sample t-test.

Results: The mean and standard deviations of the failure load were 1,170.1 ± 90.9 N for EV design and 1,450.4 ± 175.7 N for CB design. A significant difference in the compressive failure load was found (P<.05). For the failure characteristic, the EV design was found only cohesive failures within veneering porcelain, while the CB design found more failures through the zirconia framework (8 from 10 samples).

Conclusion: There was a significant difference in the failure load between two designs, and the design of the framework influences failure characteristic of zirconia crown.

No MeSH data available.


Related in: MedlinePlus

Framework and veneering thickness of the experimental crowns in this study. (A) even thickness design, (B) cutback design.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4414945&req=5

Figure 1: Framework and veneering thickness of the experimental crowns in this study. (A) even thickness design, (B) cutback design.

Mentions: The master die was scanned using the inEos Blue scanner (Sirona, Long Island City, NY, USA). Scanned data were computed and then designed for all-ceramic crown framework using the CEREC 3D software (Sirona, Long Island City, NY, USA). Two different framework designs were made. First, the 0.5 mm thick framework (EV) including 0.5 mm thick crown margin was prepared (Fig. 1A). Second, cutback design was prepared as same as that of metalceramic crowns to obtain uniform, adequate thickness and support of 0.8 mm thick of the veneering porcelain (CB) with the same crown margin 0.5 mm. (Fig. 1B).


The effect of zirconia framework design on the failure of all-ceramic crown under static loading.

Urapepon S, Taenguthai P - J Adv Prosthodont (2015)

Framework and veneering thickness of the experimental crowns in this study. (A) even thickness design, (B) cutback design.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4414945&req=5

Figure 1: Framework and veneering thickness of the experimental crowns in this study. (A) even thickness design, (B) cutback design.
Mentions: The master die was scanned using the inEos Blue scanner (Sirona, Long Island City, NY, USA). Scanned data were computed and then designed for all-ceramic crown framework using the CEREC 3D software (Sirona, Long Island City, NY, USA). Two different framework designs were made. First, the 0.5 mm thick framework (EV) including 0.5 mm thick crown margin was prepared (Fig. 1A). Second, cutback design was prepared as same as that of metalceramic crowns to obtain uniform, adequate thickness and support of 0.8 mm thick of the veneering porcelain (CB) with the same crown margin 0.5 mm. (Fig. 1B).

Bottom Line: The mean and standard deviations of the failure load were 1,170.1 ± 90.9 N for EV design and 1,450.4 ± 175.7 N for CB design.A significant difference in the compressive failure load was found (P<.05).For the failure characteristic, the EV design was found only cohesive failures within veneering porcelain, while the CB design found more failures through the zirconia framework (8 from 10 samples).

View Article: PubMed Central - PubMed

Affiliation: Prosthodontics Department, Faculty of Dentistry, Mahidol University, Bangkok, Thailand.

ABSTRACT

Purpose: This in vitro study aimed to compare the failure load and failure characteristics of two different zirconia framework designs of premolar crowns when subjected to static loading.

Materials and methods: Two types of zirconia frameworks, conventional 0.5 mm even thickness framework design (EV) and 0.8 mm cutback of full contour crown anatomy design (CB), were made for 10 samples each. The veneer porcelain was added on under polycarbonate shell crown made by vacuum of full contour crown to obtain the same total thickness of the experiment crowns. The crowns were cemented onto the Cobalt-Chromium die. The dies were tilted 45 degrees from the vertical plane to obtain the shear force to the cusp when loading. All crowns were loaded at the lingual incline of the buccal cusp until fracture using a universal testing machine with cross-head speed 0.5 mm/min. The load to fracture values (N) was recorded and statistically analyzed by independent sample t-test.

Results: The mean and standard deviations of the failure load were 1,170.1 ± 90.9 N for EV design and 1,450.4 ± 175.7 N for CB design. A significant difference in the compressive failure load was found (P<.05). For the failure characteristic, the EV design was found only cohesive failures within veneering porcelain, while the CB design found more failures through the zirconia framework (8 from 10 samples).

Conclusion: There was a significant difference in the failure load between two designs, and the design of the framework influences failure characteristic of zirconia crown.

No MeSH data available.


Related in: MedlinePlus