J Korean Acad Prosthodont.  2017 Oct;55(4):381-388. 10.4047/jkap.2017.55.4.381.

The dimension analysis of prepared natural teeth for developing customized zirconia block

• Kim MH
• Kim SH
• Yeo IS
• Yoon HI
• Lee JH
• Han JS

• KMID: 2393909
• DOI: http://doi.org/10.4047/jkap.2017.55.4.381

Abstract

PURPOSE
Unpredictable shrinkage of zirconia during sintering process causes discrepancy. Therefore, there have been attempts to reduce discrepancy by milling zirconia after sintering. However, due to the hardness of sintered zirconia, milling takes longer time, causes damage to the machine and causes chip formation. With customized zirconia block using the mean dimension of prepared natural dentition, it is expected to overcome these shortcomings.
MATERIALS AND METHODS
The mean dimension of prepared natural dentition was analyzed as STL file after scanning of prepared teeth treated at SNUDH. The transverse, frontal and sagittal planes were set using Mimics and Photoshop. 3D volume was projected on each plane, and the outer line was measured through external tangent line, and the inner line was measured through inflection point of tangent line.
RESULTS
The mean height of prepared incisal (N = 57) is 6.60 ± 1.05 mm, mesiodistal length is 2.98 ± 0.73 mm, buccolingual length is 2.04 ± 0.73 mm. The mean height of prepared premolar (N = 15) is 5.37 ± 1.49 mm, mesiodistal length is 4.10 ± 1.78 mm, buccolingual length is 5.86 ± 1.55 mm. And the mean height of prepared molar (N = 13) is 5.11 ± 1.29 mm, mesiodistal length is 6.80 ± 1.18 mm, buccolingual length is 7.34 ± 1.40 mm.
CONCLUSION
Using the mean dimension of prepared natural dentition, it is expected to be able to fabricate customized zirconia block.

Keyword

Zirconia; Sintering; Customized zirconia block

MeSH Terms

Bicuspid
Dentition
Hardness
Molar
Tooth*

Figure

• 

  Fig. 1. 3D volume was projected on each plane. The outer line was measured through external tangent line, and inner line was measured through inflection point of tangent line using Mimics auto setup. (A) Transverse Plane, (B) Frontal Plane, (C) Sagittal Plane.

• 

  Fig. 2. Mesiodistal length (X) of incisal group in transverse plane is (6.98 ± 1.05 mm, Max = 11.05 mm), buccolingual length (Y) is (7.39 ± 1.05 mm, Max = 9.84 mm).

• 

  Fig. 3. Mesiodistal length (X1) of incisal group in frontal plane is (7.50 ± 1.15 mm, Max = 11.04 mm), crown height (Y) is (9.61 ± 1.17 mm, Max = 12.80 mm).

• 

  Fig. 4. Mesiodistal length (X2) of prepared incisal group in frontal plane is (2.98 ± 0.73 mm, Min = 1.39 mm), crown height (Y2) is (6.60 ± 1.05 mm, Min = 4.11 mm).

• 

  Fig. 5. Buccolingual lenth (X1) of incisal group in sagittal plane is (6.88 ± 0.88 mm, Max = 4.04 mm), crown height (Y1) is (9.61 ± 1.17 mm, Max = 9.62 mm).

• 

  Fig. 6. Buccolingual lenth (X2) of prepared incisal group in sagittal plane is (2.04 ± 0.73 mm, Min = 0.93 mm), crown height (Y2) is (6.75 ± 1.09 mm, Min = 4.24 mm).

• 

  Fig. 7. Mesiodistal length (X) of premolar group in transverse plane is (8.01 ±1.47 mm, Max = 12.03 mm), buccolingual length (Y) is (9.74 ±1.18 mm, Max = 13.33 mm).

• 

  Fig. 8. Mesiodistal length (X1) of premolar group in frontal plane is (8.01 ± 1.46 mm, Max = 12.09 mm), crown height (Y) is (8.01 ± 1.48 mm, Max = 11.07 mm).

• 

  Fig. 9. Mesiodistal length (X2) of prepared premolar group in frontal plane is (4.10 ± 1.78 mm, Min = 1.97 mm), crown height (Y2) is (5.37 ± 1.49 mm, Min = 3.67 mm).

• 

  Fig. 10. Buccolingual lenth (X1) of premolar group in sagittal plane is (9.76 ± 1.22 mm, Max = 13.48 mm), crown height (Y1) is (8.01 ± 1.48 mm, Max = 11.07 mm).

• 

  Fig. 11. Buccolingual lenth (X2) of prepared premolar group in sagittal plane is (5.86 ± 1.55 mm, Min = 2.86 mm), crown height (Y2) is (5.38 ± 1.33 mm, Min = 4.07 mm).

• 

  Fig. 12. Mesiodistal length (X) of molar group in transverse plane is (10.87 ± 1.04 mm, Max = 12.63 mm), buccolingual length (Y) is (11.41 ± 1.18 mm, Max = 13.33 mm).

• 

  Fig. 13. Mesiodistal length (X1) of molar group in frontal plane is (10.62 ± 1.25 mm, Max = 12.44 mm), crown height (Y) is (8.15 ± 1.17 mm, Max = 10.65 mm).

• 

  Fig. 14. Mesiodistal length (X2) of prepared molar group in frontal plane is (6.80 ± 1.18 mm, Min = 4.44 mm), crown height (Y2) is (5.11 ± 1.29 mm, Min = 3.38 mm).

• 

  Fig. 15. Buccolingual lenth (X1) of molar group in sagittal plane is (11.53 ± 1.18 mm, Max = 13.48 mm), crown height (Y1) is (8.12 ± 1.19 mm, Max = 10.59 mm).

• 

  Fig. 16. Buccolingual lenth (X2) of prepared molar group in sagittal plane is (7.34 ± 1.40 mm, Min = 4.09 mm), crown height (Y2) is (5.15 ± 1.23 mm, Min = 3.63 mm).

• 

  Fig. 17. Comparison of milling area between conventional zirconia block (A) and customized zirconia block (B).

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