目標:為了以植體生物力學研究骨流失區域，本研究結合了機器視覺原理，開發了一套自動化有限元素流程，可快速將患者顎骨幾何及材料性質導入力學分析模型進行運算，可在短時間大量產生模擬分析資料，並建立植體生物力學預測模型。
材料方法: 本研究之植體自動化生物力學建模流程如下:先將醫學影像交由雙邊濾波器(Bilateral Filter)處理，再由K-means分群法(K-means Clustering)處理材料性質之辨識，通過ABAQUS Python之自動化建模腳本，得到假骨試塊力學結果。力學模型中，預設的植體直徑約為3.8mm，植體長度為13mm，假骨試塊約為40 x 20 x 32 mm之長方體，最後將假骨試塊進行力學測試，量測於指定位置之最小主應變值，並與模擬結果比較。
結果: 由實驗結果得知，骨周圍之最小主應變之值會因彈性模數變小逐漸上升。本研究開發之非均值模型與實驗之最小主應變相比，除了材料編號10之誤差較大，約21.78%，其他組誤差皆在10%以內。以最小主應變分布圖來看，最小主應變之分布與植體幾何(植體長度與植體直徑)有關，影響皮質骨破壞之區域，但對於最小主應變之極值影響很小，而患者之顎骨條件(皮質骨厚度與疏鬆骨之密度)對於最小主應變極值之影響較大，因此對於臨床而言，與其選擇適合的植體幾何，選擇顎骨條件優良的區域(皮質骨厚、骨密度高)為植體預防骨流失之關鍵。
結論:自動化建模以取得初步的成功，使用者僅需自定義所需模擬的植體尺寸，並掃描骨周圍的電腦斷層，偵測皮質骨厚度，本研究的自動化有限元素模型即可生成力學分析。

One of the causes of marginal bone loss around dental implants is too large strains occurred in the jaw bones. To predict strains surrounding the alveolar bones in the clinical situations, this study develops a semi-automatic biomechanical analysis system based on K-means clustering and finite element method (FEM). K-means clustering is used to classify voxels of the medical images into k groups of materials. After the process of K-means clustering is complete, our algorithm will construct finite element models, import the k groups of materials into this model, and conduct biomechanical analysis of dental implants. To find out the relationship between the geometry of implants and material properties of bone, the parameters, implant length (L_i), implant diameter (D_i), thickness of cortical bone (t_c), elastic modulus of cancellous bone and loading angle (θ_l), are defined. Our study shows that material properties of bone, thickness of cortical bone (t_c) and elastic modulus of cancellous bone, are more significant to reduce the minimum principal strain surrounding the alveolar bones than the geometry of implants. In the clinical view, when the location of dental implants is chosen in the thick part of cortical and hard cancellous bone, this dental implant is much stable. Our ultimate goal is to enable the design optimization of dental implants using patient-specific bone geometry and material properties.

[1] R. C. Van Staden, H. Guan, and Y. C. Loo, "Application of the finite element method in dental implant research," Comput Methods Biomech Biomed Engin, vol. 9, no. 4, pp. 257-70, Aug 2006.
[2] H. M. Frost, "Bone "mass" and the "mechanostat": a proposal," Anat Rec, vol. 219, no. 1, pp. 1-9, Sep 1987.
[3] M. Esposito, J. M. Hirsch, U. Lekholm, and P. Thomsen, "Biological factors contributing to failures of osseointegrated oral implants. (I). Success criteria and epidemiology," (in eng), Eur J Oral Sci, vol. 106, no. 1, pp. 527-51, Feb 1998.
[4] F. Isidor, "Loss of osseointegration caused by occlusal load of oral implants. A clinical and radiographic study in monkeys," (in eng), Clin Oral Implants Res, vol. 7, no. 2, pp. 143-52, Jun 1996.
[5] F. Isidor, "Histological evaluation of peri-implant bone at implants subjected to occlusal overload or plaque accumulation," (in eng), Clin Oral Implants Res, vol. 8, no. 1, pp. 1-9, Feb 1997.
[6] J. Duyck and K. Vandamme, "The effect of loading on peri-implant bone: a critical review of the literature," (in eng), J Oral Rehabil, vol. 41, no. 10, pp. 783-94, Oct 2014.
[7] L. Baggi, I. Cappelloni, M. Di Girolamo, F. Maceri, and G. Vairo, "The influence of implant diameter and length on stress distribution of osseointegrated implants related to crestal bone geometry: a three-dimensional finite element analysis," (in English), J Prosthet Dent, vol. 100, no. 6, pp. 422-31, Dec 2008.
[8] L. Kong et al., "Selections of the cylinder implant neck taper and implant end fillet for optimal biomechanical properties: a three-dimensional finite element analysis," J Biomech, vol. 41, no. 5, pp. 1124-30, 2008.
[9] I. C. Chou, S. Y. Lee, and C. P. Jiang, "Effects of implant neck design on primary stability and overload in a type IV mandibular bone," Int J Numer Method Biomed Eng, vol. 30, no. 11, pp. 1223-37, Nov 2014.
[10] S. Y. Liu, C. B. Tang, J. H. Yu, W. Y. Dai, Y. D. Bao, and D. Hu, "The Effect of Platform Switching on Stress Distribution in Implants and Periim Plant Bone Studied by Nonlinear Finite Element Analysis," (in English), Journal of Prosthetic Dentistry, Article vol. 112, no. 5, pp. 1111-1118, Nov 2014.
[11] O. Eraslan and O. Inan, "The effect of thread design on stress distribution in a solid screw implant: a 3D finite element analysis," (in eng), Clin Oral Investig, vol. 14, no. 4, pp. 411-6, Aug 2010.
[12] J. Chen, C. Rungsiyakull, W. Li, Y. Chen, M. Swain, and Q. Li, "Multiscale design of surface morphological gradient for osseointegration," J Mech Behav Biomed Mater, vol. 20, pp. 387-97, Apr 2013.
[13] C. L. Chang, C. S. Chen, C. H. Huang, and M. L. Hsu, "Finite element analysis of the dental implant using a topology optimization method," (in English), Med Eng Phys, vol. 34, no. 7, pp. 999-1008, Sep 2012.
[14] M. H. Bartley, Jr., J. S. Arnold, R. K. Haslam, and W. S. Jee, "The relationship of bone strength and bone quantity in health, disease, and aging," J Gerontol, vol. 21, no. 4, pp. 517-21, Oct 1966.
[15] D. R. Carter and W. C. Hayes, "Compressive Behavior of Bone as a 2-Phase Porous Structure," (in English), Journal of Bone and Joint Surgery-American Volume, vol. 59, no. 7, pp. 954-962, 1977 1977.
[16] J. A. MacNeil and S. K. Boyd, "Accuracy of high-resolution peripheral quantitative computed tomography for measurement of bone quality," Med Eng Phys, vol. 29, no. 10, pp. 1096-105, Dec 2007.
[17] J. T. Ho, J. Wu, H. L. Huang, M. Y. Chen, L. J. Fuh, and J. T. Hsu, "Trabecular bone structural parameters evaluated using dental cone-beam computed tomography: cellular synthetic bones," (in eng), Biomed Eng Online, vol. 12, p. 115, Nov 9 2013.
[18] A. Tabassum, G. J. Meijer, J. G. Wolke, and J. A. Jansen, "Influence of surgical technique and surface roughness on the primary stability of an implant in artificial bone with different cortical thickness: a laboratory study," (in English), Clin Oral Implants Res, Article vol. 21, no. 2, pp. 213-20, Feb 2010.
[19] C. Liu et al., "Relation between insertion torque and bone-implant contact percentage: an artificial bone study," (in English), Clin Oral Investig, Article vol. 16, no. 6, pp. 1679-84, Dec 2012.
[20] S. H. Hsu, Y. Cao, K. Huang, M. Feng, and J. M. Balter, "Investigation of a method for generating synthetic CT models from MRI scans of the head and neck for radiation therapy," (in English), Phys Med Biol, Article vol. 58, no. 23, pp. 8419-35, Dec 7 2013.
[21] J. Chen et al., "Shape Optimization for Additive Manufacturing of Removable Partial Dentures--A New Paradigm for Prosthetic CAD/CAM," PLoS One, vol. 10, no. 7, p. e0132552, 2015.
[22] R. Hambli, "Multiscale prediction of crack density and crack length accumulation in trabecular bone based on neural networks and finite element simulation," (in English), International Journal for Numerical Methods in Biomedical Engineering, vol. 27, no. 4, pp. 461-475, Apr 2011.
[23] K. K. Nishiyama, M. Ito, A. Harada, and S. K. Boyd, "Classification of women with and without hip fracture based on quantitative computed tomography and finite element analysis," Osteoporos Int, vol. 25, no. 2, pp. 619-26, Feb 2014.
[24] C. Tomasi and R. Manduchi, "Bilateral filtering for gray and color images," in Sixth International Conference on Computer Vision (IEEE Cat. No.98CH36271), 1998, pp. 839-846.
[25] J. MacQueen, "Some methods for classification and analysis of multivariate observations," in Proceedings of the Fifth Berkeley Symposium on Mathematical Statistics and Probability, Volume 1: Statistics, Berkeley, Calif., 1967, pp. 281-297: University of California Press.
[26] D. Arthur and S. Vassilvitskii, "k-means++: the advantages of careful seeding," presented at the Proceedings of the eighteenth annual ACM-SIAM symposium on Discrete algorithms, New Orleans, Louisiana, 2007.
[27] H. L. Huang, Y. Y. Chang, D. J. Lin, Y. F. Li, K. T. Chen, and J. T. Hsu, "Initial stability and bone strain evaluation of the immediately loaded dental implant: an in vitro model study," (in eng), Clin Oral Implants Res, vol. 22, no. 7, pp. 691-698, Jul 2011.
[28] M. Codari, M. Caffini, G. M. Tartaglia, C. Sforza, and G. Baselli, "Computer-aided cephalometric landmark annotation for CBCT data," (in English), Int J Comput Assist Radiol Surg, Article vol. 12, no. 1, pp. 113-121, Jan 2017.
[29] C. E. Misch, "Stress Treatment Theorem for Implant Dentistry:The Key to Implant Treatment Plans," in Dental Implant ProstheticsSt. Louis: Mosby, 2015, pp. 159-192.
[30] J. Long, E. Shelhamer, and T. Darrell, "Fully convolutional networks for semantic segmentation," in Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2015, pp. 3431-3440.
[31] O. Ronneberger, P. Fischer, and T. Brox, "U-net: Convolutional networks for biomedical image segmentation," in International Conference on Medical Image Computing and Computer-Assisted Intervention, 2015, pp. 234-241: Springer.
[32] Z. Lun, M. Gadelha, E. Kalogerakis, S. Maji, and R. Wang, "3D Shape Reconstruction from Sketches via Multi-view Convolutional Networks," arXiv preprint arXiv:1707.06375, 2017.
[33] X. Han, "MR-based synthetic CT generation using a deep convolutional neural network method," (in eng), Med Phys, vol. 44, no. 4, pp. 1408-1419, Apr 2017.
[34] S. S. Mohseni Salehi, D. Erdogmus, and A. Gholipour, "Auto-Context Convolutional Neural Network (Auto-Net) for Brain Extraction in Magnetic Resonance Imaging," (in eng), IEEE Trans Med Imaging, vol. 36, no. 11, pp. 2319-2330, Nov 2017.