{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,15]],"date-time":"2026-05-15T20:18:49Z","timestamp":1778876329184,"version":"3.51.4"},"reference-count":46,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2019,12,12]],"date-time":"2019-12-12T00:00:00Z","timestamp":1576108800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology, Taiwan","doi-asserted-by":"publisher","award":["MOST108-2218-E-011-024"],"award-info":[{"award-number":["MOST108-2218-E-011-024"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology, Taiwan","doi-asserted-by":"publisher","award":["MOST107-2218-E-011-015"],"award-info":[{"award-number":["MOST107-2218-E-011-015"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology, Taiwan","doi-asserted-by":"publisher","award":["MOST107-2221-E-011-114-MY2"],"award-info":[{"award-number":["MOST107-2221-E-011-114-MY2"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology, Taiwan","doi-asserted-by":"publisher","award":["MOST107-2221-E-011-112-MY2"],"award-info":[{"award-number":["MOST107-2221-E-011-112-MY2"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Periodontal diagnosis requires discovery of the relations among teeth, gingiva (i.e., gums), and alveolar bones, but alveolar bones are inside gingiva and not visible for inspection. Traditional probe examination causes pain, and X-ray based examination is not suited for frequent inspection. This work develops an automatic non-invasive periodontal inspection framework based on gum penetrative Optical Coherence Tomography (OCT), which can be frequently applied without high radiation. We sum up interference responses of all penetration depths for all shooting directions respectively to form the shooting amplitude projection. Because the reaching interference strength decays exponentially with tissues\u2019 penetration depth, this projection mainly reveals the responses of the top most gingiva or teeth. Since gingiva and teeth have different air-tissue responses, the gumline, revealing itself as an obvious boundary between teeth and gingiva, is the basis line for periodontal inspection. Our system can also automatically identify regions of gingiva, teeth, and alveolar bones from slices of the cross-sectional volume. Although deep networks can successfully and possibly segment noisy maps, reducing the number of manually labeled maps for training is critical for our framework. In order to enhance the effectiveness and efficiency of training and classification, we adjust Snake segmentation to consider neighboring slices in order to locate those regions possibly containing gingiva-teeth and gingiva\u2013alveolar boundaries. Additionally, we also adapt a truncated direct logarithm based on the Snake-segmented region for intensity quantization to emphasize these boundaries for easier identification. Later, the alveolar-gingiva boundary point directly under the gumline is the desired alveolar sample, and we can measure the distance between the gumline and alveolar line for visualization and direct periodontal inspection. At the end, we experimentally verify our choice in intensity quantization and boundary identification against several other algorithms while applying the framework to locate gumline and alveolar line in vivo data successfully.<\/jats:p>","DOI":"10.3390\/s19245496","type":"journal-article","created":{"date-parts":[[2019,12,12]],"date-time":"2019-12-12T11:06:41Z","timestamp":1576148801000},"page":"5496","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["OCT-Based Periodontal Inspection Framework"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8578-3101","authenticated-orcid":false,"given":"Yu-Chi","family":"Lai","sequence":"first","affiliation":[{"name":"Department of Computer Science and Information Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chia-Hsing","family":"Chiu","sequence":"additional","affiliation":[{"name":"Department of Computer Science and Information Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2728-036X","authenticated-orcid":false,"given":"Zhong-Qi","family":"Cai","sequence":"additional","affiliation":[{"name":"Department of Computer Science and Information Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jin-Yang","family":"Lin","sequence":"additional","affiliation":[{"name":"Department of Computer Science and Information Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chih-Yuan","family":"Yao","sequence":"additional","affiliation":[{"name":"Department of Computer Science and Information Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dong-Yuan","family":"Lyu","sequence":"additional","affiliation":[{"name":"Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shyh-Yuan","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan"},{"name":"Department of Stomatology, Taipei Veterans General Hospital, Taipei 112, Taiwan"},{"name":"Department of Dentistry, Taipei City Hospital, Taipei 103, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kuo-Wei","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Computer Science and Information Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"I-Yu","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Computer Science and Information Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,12,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1111\/j.1600-0757.1993.tb00220.x","article-title":"Prevalence, extent, severity and progression of periodontal disease","volume":"2","author":"Brown","year":"1993","journal-title":"Periodontology 2000"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1111\/j.1600-051X.1982.tb02108.x","article-title":"Patterns of progression and regression of advanced destructive periodontal disease","volume":"9","author":"Goodson","year":"1982","journal-title":"J. Clin. Periodontol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1111\/j.1600-051X.1983.tb01266.x","article-title":"Relative effects of plaque control and instrumentation on the clinical parameters of human periodontal disease","volume":"10","author":"Cercek","year":"1983","journal-title":"J. Clin. Periodontol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"262","DOI":"10.1902\/jop.1985.56.5.262","article-title":"Measuring and interpreting increases in probing depth and attachment loss","volume":"56","author":"Aeppli","year":"1985","journal-title":"J. Periodontol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1902\/jop.2009.090419","article-title":"An update on novel non-invasive approaches for periodontal diagnosis","volume":"81","author":"Xiang","year":"2010","journal-title":"J. Periodontol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1902\/jop.1982.53.5.311","article-title":"Relationship between alveolar bone measured by 125I absorptiometry with analysis of standardized radiographs: 2. Bjorn technique","volume":"53","author":"Ortman","year":"1982","journal-title":"J. Periodontol."},{"key":"ref_7","first-page":"8","article-title":"Assessment of periodontal disease progression: Application of new technology to conventional tools","volume":"11","author":"Jeffcoat","year":"1989","journal-title":"Periodontal Case Rep. Publ. Northeast. Soc. Periodontists"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"415","DOI":"10.1111\/j.1600-0765.1991.tb01731.x","article-title":"Use of digital radiography to demonstrate the potential of naproxen as an adjunct in the treatment of rapidly progressive periodontitis","volume":"26","author":"Jeffcoat","year":"1991","journal-title":"J. Periodontal Res."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"230","DOI":"10.1364\/OE.3.000230","article-title":"Dental OCT","volume":"3","author":"Colston","year":"1998","journal-title":"Opt. Express."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1159\/000016571","article-title":"Polarization\u2014Sensitive optical coherence tomography of dental structures","volume":"34","author":"Baumgartner","year":"2000","journal-title":"Caries Res."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"216","DOI":"10.1117\/12.273591","article-title":"Optical Coherence Tomography for Diagnosing Periodontal Disease","volume":"2973","author":"Colston","year":"1997","journal-title":"Proc. SPIE"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"252","DOI":"10.1016\/j.ajodo.2007.10.037","article-title":"Optical approach to the periodontal ligament under orthodontic tooth movement: A preliminary study with optical coherence tomography","volume":"135","author":"Baek","year":"2009","journal-title":"Am. J. Orthod. Dentofacial Orthop."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"717","DOI":"10.1111\/j.1601-0825.2010.01684.x","article-title":"Optical diagnostics in the oral cavity: An overview","volume":"16","author":"Holtzman","year":"2010","journal-title":"Oral Dis."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1087","DOI":"10.1902\/jop.2015.150047","article-title":"Non-Invasive Periodontal Probing Through Fourier-Domain Optical Coherence Tomography","volume":"86","author":"Mota","year":"2015","journal-title":"J. Periodontol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"862","DOI":"10.1002\/jbio.201600082","article-title":"In vivo assessment of periodontal structures and measurement of gingival sulcus with Optical Coherence Tomography: A pilot study","volume":"10","author":"Fernandes","year":"2017","journal-title":"J. Biophotonics"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"e201800209","DOI":"10.1002\/jbio.201800209","article-title":"Optical coherence tomography follow-up of patients treated from periodontal disease","volume":"12","author":"Fernandes","year":"2019","journal-title":"J. Biophotonics"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"180","DOI":"10.1111\/j.1600-0757.2006.00192.x","article-title":"Microbiological goals of periodontal therapy","volume":"42","author":"Teles","year":"2006","journal-title":"Periodontology 2000"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"508","DOI":"10.1902\/jop.1988.59.8.508","article-title":"Microbiologic assessments to enhance periodontal diagnosis","volume":"59","author":"Greenstein","year":"1988","journal-title":"J. Periodontol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"182","DOI":"10.1177\/08959374930070020901","article-title":"Current status of tests for periodontal disease","volume":"7","author":"Lamster","year":"1993","journal-title":"Adv. Dent. Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"504","DOI":"10.2144\/97233rr01","article-title":"Multiplex PCR: Critical parameters and step-by-step protocol","volume":"23","author":"Henegariu","year":"1997","journal-title":"Biotechniques"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1034\/j.1600-0757.2001.2260106.x","article-title":"Genetic predisposition to periodontitis in children and young adults","volume":"26","author":"Hodge","year":"2001","journal-title":"Periodontology 2000"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"102","DOI":"10.1111\/j.1600-0757.2006.00164.x","article-title":"The role of genetic polymorphisms in periodontitis","volume":"43","author":"Yoshie","year":"2007","journal-title":"Periodontology 2000"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1111\/j.1600-051X.2007.01055.x","article-title":"The association of the composite IL-1 genotype with periodontitis progression and\/or treatment outcomes: A systematic review","volume":"34","author":"Lang","year":"2007","journal-title":"J. Clin. Periodontol."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Lai, Y.C., Lin, J.Y., Yao, C.Y., Lyu, D.Y., Lee, S.Y., Chen, K.W., and Chen, I.Y. (2019). Interactive OCT-Based Tooth Scan and Reconstruction. Sensors, 19.","DOI":"10.3390\/s19194234"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1240","DOI":"10.1109\/TMI.2016.2538465","article-title":"Brain tumor segmentation using convolutional neural networks in MRI images","volume":"35","author":"Pereira","year":"2016","journal-title":"IEEE Trans. Med Imaging"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1310","DOI":"10.1109\/TMI.2010.2046908","article-title":"N4ITK: Improved N3 bias correction","volume":"29","author":"Tustison","year":"2010","journal-title":"IEEE Trans. Med Imaging"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Poudel, R., Lamata, P., and Montana, G. (2016). Recurrent fully convolutional neural networks for multi-slice MRI cardiac segmentation. Reconstruction, Segmentation, and Analysis of Medical Images, Springer.","DOI":"10.1007\/978-3-319-52280-7_8"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1602","DOI":"10.1118\/1.1580485","article-title":"Massive training artificial neural network (MTANN) for reduction of false positives in computerized detection of lung nodules in low-dose computed tomography","volume":"30","author":"Suzuki","year":"2003","journal-title":"Med. Phys."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Van Ginneken, B., Setio, A., Jacobs, C., and Ciompi, F. (2015, January 16\u201319). Off-the-shelf convolutional neural network features for pulmonary nodule detection in computed tomography scans. Proceedings of the 2015 IEEE 12th International Symposium on Biomedical Imaging (ISBI), New York, NY, USA.","DOI":"10.1109\/ISBI.2015.7163869"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1178","DOI":"10.1126\/science.1957169","article-title":"Optical coherence tomography","volume":"254","author":"Huang","year":"1991","journal-title":"Science"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1205","DOI":"10.1109\/2944.796348","article-title":"Optical coherence tomography (OCT): A review","volume":"5","author":"Schmitt","year":"1999","journal-title":"IEEE J. Sel. Top. Quantum Electron."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"218","DOI":"10.1016\/j.ajo.2004.03.019","article-title":"Optical coherence tomography (OCT) macular and peripapillary retinal nerve fiber layer measurements and automated visual fields","volume":"138","author":"Wollstein","year":"2004","journal-title":"Am. J. Ophthalmol."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Avanaki, M., Laissue, P., Podoleanu, A., and Hojjat, A. (2008, January 6\u201312). Denoising based on noise parameter estimation in speckled OCT images using neural network. Proceedings of the 1st Canterbury Workshop on Optical Coherence Tomography and Adaptive Optics, Canterbury, UK.","DOI":"10.1117\/12.814937"},{"key":"ref_34","unstructured":"R\u00f6hlig, M., Rosenthal, P., Schmidt, C., Schumann, H., and Stachs, O. (2017, January 12\u201313). Visual Analysis of Optical Coherence Tomography Data in Ophthalmology. Proceedings of the EuroVA@ EuroVis, Barcelona, Spain."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"20029","DOI":"10.1364\/OE.18.020029","article-title":"Ultrahigh speed 1050 nm swept source\/Fourier domain OCT retinal and anterior segment imaging at 100,000 to 400,000 axial scans per second","volume":"18","author":"Potsaid","year":"2010","journal-title":"Opt. Express"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2278","DOI":"10.1109\/5.726791","article-title":"Gradient based learning applied to document recognition","volume":"86","author":"LeCun","year":"1998","journal-title":"Proc. IEEE"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"He, K., Zhang, X., Ren, S., and Sun, J. (2016, January 27\u201330). Deep Residual Learning for Image Recognition. Proceedings of the 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), Las Vegas, NV, USA.","DOI":"10.1109\/CVPR.2016.90"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"2481","DOI":"10.1109\/TPAMI.2016.2644615","article-title":"Segnet: A deep convolutional encoder-decoder architecture for image segmentation","volume":"39","author":"Badrinarayanan","year":"2017","journal-title":"IEEE Trans. Pattern Anal. Mach. Intell."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1364\/OE.9.000024","article-title":"How to optimize OCT image","volume":"9","author":"Yu","year":"2001","journal-title":"Opt. Express"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1007\/BF00133570","article-title":"Snakes: Active contour models","volume":"1","author":"Kass","year":"1988","journal-title":"Int. J. Comput. Vis."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1145\/1015706.1015719","article-title":"Lazy snapping","volume":"23","author":"Li","year":"2004","journal-title":"Acm Trans. Graph."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Canny, J. (1987). A computational approach to edge detection. Readings in Computer Vision, Elsevier.","DOI":"10.1016\/B978-0-08-051581-6.50024-6"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1023\/A:1020874308076","article-title":"A multiphase level set framework for image segmentation using the Mumford and Shah model","volume":"50","author":"Vese","year":"2002","journal-title":"Int. J. Comput. Vis."},{"key":"ref_44","unstructured":"Kingma, D., and Ba, J. (2015, January 7\u20139). Adam: A method for stochastic optimization. Proceedings of the International Conference on Learning Representations (ICLR), San Diego, CA, USA."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1145\/357994.358023","article-title":"A Fast Parallel Algorithm for Thinning Digital Patterns","volume":"27","author":"Zhang","year":"1984","journal-title":"Commun. ACM"},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Friedman, M., and Abraham, K. (1999). Introduction to Pattern Recognition: Statistical, Structural, Neural, and Fuzzy Logic Approaches, World Scientific. [2nd ed.].","DOI":"10.1142\/3641"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/24\/5496\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:41:56Z","timestamp":1760190116000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/24\/5496"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,12,12]]},"references-count":46,"journal-issue":{"issue":"24","published-online":{"date-parts":[[2019,12]]}},"alternative-id":["s19245496"],"URL":"https:\/\/doi.org\/10.3390\/s19245496","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,12,12]]}}}