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The influence of various core designs on stress distribution in the veneered zirconia crown: a finite element analysis study.

Ha SR, Kim SH, Han JS, Yoo SH, Jeong SC, Lee JB, Yeo IS - J Adv Prosthodont (2013)

Bottom Line: In the test simulating masticatory force, the MPS was concentrated around the loading points, and the compressive stresses were located at the 3 mm height lingual shoulder region, when the load was applied horizontally.MPS increased in the shoulder region as the shoulder height increased.This study suggested that reinforced shoulder play an essential role in the success of the zirconia restoration, and veneer fracture due to occlusal loading can be prevented by proper core design, such as shoulder.

View Article: PubMed Central - PubMed

Affiliation: Department of Dentistry, Ajou University School of Medicine, Suwon, Republic of Korea.

ABSTRACT

Purpose: The purpose of this study was to evaluate various core designs on stress distribution within zirconia crowns.

Materials and methods: Three-dimensional finite element models, representing mandibular molars, comprising a prepared tooth, cement layer, zirconia core, and veneer porcelain were designed by computer software. The shoulder (1 mm in width) variations in core were incremental increases of 1 mm, 2 mm and 3 mm in proximal and lingual height, and buccal height respectively. To simulate masticatory force, loads of 280 N were applied from three directions (vertical, at a 45° angle, and horizontal). To simulate maximum bite force, a load of 700 N was applied vertically to the crowns. Maximum principal stress (MPS) was determined for each model, loading condition, and position.

Results: In the maximum bite force simulation test, the MPSs on all crowns observed around the shoulder region and loading points. The compressive stresses were located in the shoulder region of the veneer-zirconia interface and at the occlusal region. In the test simulating masticatory force, the MPS was concentrated around the loading points, and the compressive stresses were located at the 3 mm height lingual shoulder region, when the load was applied horizontally. MPS increased in the shoulder region as the shoulder height increased.

Conclusion: This study suggested that reinforced shoulder play an essential role in the success of the zirconia restoration, and veneer fracture due to occlusal loading can be prevented by proper core design, such as shoulder.

No MeSH data available.


Related in: MedlinePlus

Lingual side view of maximum principal stress distributions of 10 models subjected to masticatory force. (1) load of 280 N at 0° to the tooth axis (vertical direction), (2) load of 280 N at 45° to the tooth axis, towards the lingual margin, and (3) load of 280 N at 90° to the tooth axis, towards the lingual surface (horizontal direction). A: Model 1, B: Model 2, C: Model 3, B: Model 4, E: Model 5, F: Model 6, G: Model 7, H: Model 8, I: Model 9 and J: Model 10.
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Figure 7: Lingual side view of maximum principal stress distributions of 10 models subjected to masticatory force. (1) load of 280 N at 0° to the tooth axis (vertical direction), (2) load of 280 N at 45° to the tooth axis, towards the lingual margin, and (3) load of 280 N at 90° to the tooth axis, towards the lingual surface (horizontal direction). A: Model 1, B: Model 2, C: Model 3, B: Model 4, E: Model 5, F: Model 6, G: Model 7, H: Model 8, I: Model 9 and J: Model 10.

Mentions: The MPS distributions within ten models subjected to masticatory force at three directions are presented in Fig. 6 and 7. It was observed that the MPS on the buccal and lingual shoulder was high in the models those had 3 mm height shoulder and slightly high in the models those had 2 mm height shoulder, when the load was applied to vertical direction. When the load was applied to angularly, the MPS on the buccal margin was high regardless of existence of buccal shoulder, and that on the lingual margin was high in the models those had buccal shoulder. Angular loading resulted in a general increase of MPS compared to vertical loading in lingual shoulder. The supportive effect of lingual shoulder increased as the load direction changed from vertical to angularly. When the load was applied to horizontal direction, the MPS concentrated on the buccal cervical veneer in models without shoulder. No significant changes in stress area were observed at lingual shoulder except for 3 mm height shoulder.


The influence of various core designs on stress distribution in the veneered zirconia crown: a finite element analysis study.

Ha SR, Kim SH, Han JS, Yoo SH, Jeong SC, Lee JB, Yeo IS - J Adv Prosthodont (2013)

Lingual side view of maximum principal stress distributions of 10 models subjected to masticatory force. (1) load of 280 N at 0° to the tooth axis (vertical direction), (2) load of 280 N at 45° to the tooth axis, towards the lingual margin, and (3) load of 280 N at 90° to the tooth axis, towards the lingual surface (horizontal direction). A: Model 1, B: Model 2, C: Model 3, B: Model 4, E: Model 5, F: Model 6, G: Model 7, H: Model 8, I: Model 9 and J: Model 10.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3675293&req=5

Figure 7: Lingual side view of maximum principal stress distributions of 10 models subjected to masticatory force. (1) load of 280 N at 0° to the tooth axis (vertical direction), (2) load of 280 N at 45° to the tooth axis, towards the lingual margin, and (3) load of 280 N at 90° to the tooth axis, towards the lingual surface (horizontal direction). A: Model 1, B: Model 2, C: Model 3, B: Model 4, E: Model 5, F: Model 6, G: Model 7, H: Model 8, I: Model 9 and J: Model 10.
Mentions: The MPS distributions within ten models subjected to masticatory force at three directions are presented in Fig. 6 and 7. It was observed that the MPS on the buccal and lingual shoulder was high in the models those had 3 mm height shoulder and slightly high in the models those had 2 mm height shoulder, when the load was applied to vertical direction. When the load was applied to angularly, the MPS on the buccal margin was high regardless of existence of buccal shoulder, and that on the lingual margin was high in the models those had buccal shoulder. Angular loading resulted in a general increase of MPS compared to vertical loading in lingual shoulder. The supportive effect of lingual shoulder increased as the load direction changed from vertical to angularly. When the load was applied to horizontal direction, the MPS concentrated on the buccal cervical veneer in models without shoulder. No significant changes in stress area were observed at lingual shoulder except for 3 mm height shoulder.

Bottom Line: In the test simulating masticatory force, the MPS was concentrated around the loading points, and the compressive stresses were located at the 3 mm height lingual shoulder region, when the load was applied horizontally.MPS increased in the shoulder region as the shoulder height increased.This study suggested that reinforced shoulder play an essential role in the success of the zirconia restoration, and veneer fracture due to occlusal loading can be prevented by proper core design, such as shoulder.

View Article: PubMed Central - PubMed

Affiliation: Department of Dentistry, Ajou University School of Medicine, Suwon, Republic of Korea.

ABSTRACT

Purpose: The purpose of this study was to evaluate various core designs on stress distribution within zirconia crowns.

Materials and methods: Three-dimensional finite element models, representing mandibular molars, comprising a prepared tooth, cement layer, zirconia core, and veneer porcelain were designed by computer software. The shoulder (1 mm in width) variations in core were incremental increases of 1 mm, 2 mm and 3 mm in proximal and lingual height, and buccal height respectively. To simulate masticatory force, loads of 280 N were applied from three directions (vertical, at a 45° angle, and horizontal). To simulate maximum bite force, a load of 700 N was applied vertically to the crowns. Maximum principal stress (MPS) was determined for each model, loading condition, and position.

Results: In the maximum bite force simulation test, the MPSs on all crowns observed around the shoulder region and loading points. The compressive stresses were located in the shoulder region of the veneer-zirconia interface and at the occlusal region. In the test simulating masticatory force, the MPS was concentrated around the loading points, and the compressive stresses were located at the 3 mm height lingual shoulder region, when the load was applied horizontally. MPS increased in the shoulder region as the shoulder height increased.

Conclusion: This study suggested that reinforced shoulder play an essential role in the success of the zirconia restoration, and veneer fracture due to occlusal loading can be prevented by proper core design, such as shoulder.

No MeSH data available.


Related in: MedlinePlus