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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

Maximum principal stress distributions of 10 models subjected to maximum bite force. Maximum principal stress concentrated in the areas around loading points on the crown surface. A: Model 1, B: Model 2, C: Model 3, D: 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 4: Maximum principal stress distributions of 10 models subjected to maximum bite force. Maximum principal stress concentrated in the areas around loading points on the crown surface. A: Model 1, B: Model 2, C: Model 3, D: Model 4, E: Model 5, F: Model 6, G: Model 7, H: Model 8, I: Model 9 and J: Model 10.

Mentions: Fig. 4 and 5 show the maximum principal stress (MPS) which was evaluated for the ten models under maximum bite force. Ten models had different distribution of MPS. This depicts the relative decrease in MPS levels as a function of shoulder increase at the ceramic core cervical region. It was observed that the MPS area on the buccal shoulder increased and that on the buccal veneer decreased as the height of the buccal shoulder increased up to 3 mm from the margin. This phenomenon was dramatic in model 10 which had the highest buccal shoulder. However, the decrease of MPS on the veneer was small even the height of shoulder increased gradually except for model 10. As the height of the lingual shoulder increased, the MPS on the lingual shoulder increased and that on the lingual veneer decreased. Interestingly, the MPS on the proximal margin area was high in all models. The models those had 3 mm height lingual shoulder showed high MPS on the lingual 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)

Maximum principal stress distributions of 10 models subjected to maximum bite force. Maximum principal stress concentrated in the areas around loading points on the crown surface. A: Model 1, B: Model 2, C: Model 3, D: 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 4: Maximum principal stress distributions of 10 models subjected to maximum bite force. Maximum principal stress concentrated in the areas around loading points on the crown surface. A: Model 1, B: Model 2, C: Model 3, D: Model 4, E: Model 5, F: Model 6, G: Model 7, H: Model 8, I: Model 9 and J: Model 10.
Mentions: Fig. 4 and 5 show the maximum principal stress (MPS) which was evaluated for the ten models under maximum bite force. Ten models had different distribution of MPS. This depicts the relative decrease in MPS levels as a function of shoulder increase at the ceramic core cervical region. It was observed that the MPS area on the buccal shoulder increased and that on the buccal veneer decreased as the height of the buccal shoulder increased up to 3 mm from the margin. This phenomenon was dramatic in model 10 which had the highest buccal shoulder. However, the decrease of MPS on the veneer was small even the height of shoulder increased gradually except for model 10. As the height of the lingual shoulder increased, the MPS on the lingual shoulder increased and that on the lingual veneer decreased. Interestingly, the MPS on the proximal margin area was high in all models. The models those had 3 mm height lingual shoulder showed high MPS on the lingual 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