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Objective To evaluate the palatal rugae individual-specific properties and stability before and after orthodontic treatments for investigating the reliability of palatal rugae for individual identification of forensic dentistry based on the palatal rugae model ananlysis. Methods Maxillary models of 70 patients were obtained before and after orthodontic treatments respectively. Palatal rugae morphologic changes and individual identification were examined by model analysis including changes in number, orientation, shape, and length of palatal rugae, as well as mesial and distal endpoint displacement in the anterioposterior(AP) and mesiodistal (MD) direction. Furthermore, The examination of palatal rugae average match accuracy(%) was performed between the pre-treatment and post-treatment orthodontics models and post-treatment and duplicated post-treatment orthodontics models. Results ① The palatal rugae morphological changes were found and the incidence of palatal rugae changes were showed in length(28.6%), segmenta-tion(4.3%); unification(2.9%); orientation(1.4%) and shape(1.4%) after orthodontic treatment. Also the displacement of the distal endpoint of palatal rugae was 45.7% for anterioposterior indirection, 40% for mesiodistal indirection after orthodontic treatment, while the anterioposterior displacement of the mesial endpoint of palatal rugae was 32.9% and mesiodistal displacement was 17.1%. ② The identical palatal rugae patterns were not found both the pre-treatment and post-treatment groups. ③ The palatal rugae average match accuracy was 92.19% between pre-treatment and post-treatment groups, however, the rate had increased by 99.05% when matching the palatal rugae patterns of post-treatment groups to their duplicates. Conclusion Palatal rugae patterns have the high specific properties to each indivi-dual. Although there are some changes in morphology of palatal rugae after orthodontic treatment, it still can be used as a novel method for individual identification in forensic dentistry.
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Objective To analyze the morphological matching rate with a digital image recognition system in pre-and post-orthodontic treatments,and to provide forensic dentistry evidence for individual identification.Methods High-resolution digital images of the palatal rugae were taken under particular conditions from each patient in pre-and post-orthodontic treatments.Features of each digital image were extracted using a digital image recognition system and collected in the palatal rugae database.Data of the palatal rugae werematched by MATLAB software system.Results From the matching results,the accuracy rate of individual identification of orthodontic patients was 100％.The accuracy rate in matching palatal rugae patterns in pre-and post-orthodontic treatments was 95.67％.The results were statistically significant with P＜0.05.Conclusion Palatal rugae pattern is highly individual-specific.The morphologyofpalatal rugaecould bechangedby theorthodontic treatment,however,these changes may not greatly influence individual identification in forensic dentistry,providing a new potential to individual identification.
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Objective To establish a digital system for forensic identiifcation of the palatal rugae and evaluate its application effects. Methods High-resolution digital images of the palatal rugae were harvested under the standard condition and processed including data collection, noise reduction, contrast enhancement, image segmentation, feature extraction, edge detection, and information matching. Apply an MATLAB software system to develop a digital system for forensic identiifcation of the palatal rugae ,and its application effects were evaluated. Results A digital system for forensic identification of the palatal rugae was successfully established. The digital system had an accuracy rate of 100%. Conclusion Establishing a digital system for forensic identiifcation of the palatal rugae provides a novel method for forensic identiifcation.
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Objective To study the role of sebaceous gland and its secretion in the progress of abnormal scar and to provide a new idea to prevent pathological scar. Method The sites, pathogenesis and pathological changes were compared between pathological and normal scars.Results Pathological scar often occurred at post-ear, upper lips, maxillofacial skin, and deltoid muscle skin of upper limbs; normal scar often occurred at mid-face, forehead, nose’s tip, and proximal extremity of limbs. Several rows of sebaceous gland and its secretion could be found at the edges of pathological scar, large quantity of sebaceous gland had changes of ductal dilation, and large amount of the secretion accumulated in the cavity in pathological scar; however, on the normal scar base and edges, seldomly showed the expanded sebaceous gland and accumulated secretion. Conclusions Sebaceous gland and its secretion could stimulate the growth of scar. To control the action of sebaceous gland and the formation of secretion could inhibit the formation of pathological scar.