Abstract The issue of multimorbidity in children and adolescents is becoming increasingly prominent, but there is no consensus on the definition of multimorbidity. As research deepens, issues related to the comparability and standardization of relevant findings are gradually emerging. As a solution, a systematic review of both domestic and international research on multimorbidity is conducted, and a classification system for defining the concept of multimorbidity is proposed, offering more convenient conditions for the advancement of future research and cross study exchange.

Objective To study 3D construction and printing of bone tissue engineering scaffolds by bone defect modeling on Mimics software based on CT data. Methods CT data of jaw bone defect from patients were acquired and the images were segmented using threshold segmentation combined with region growing . The three dimensional model was reconstructed by Boolean operation. The individual 3D digital model was reconstructed with internal structure by combining with computer; preparing poly-lactic acid scaffold in virtue of 3D technology. Results Using the Mimics software, we successfully constructed a 3D digital reconstruction model of bone defect based on CT data. The constructed scaffold model with certain internal form and structure was matched with the bone defect of patients, and the constructed model was exported onto STL standard format, which may be in common use. Conclusion The 3D digital model of bone defect scaffolds may effectively be reconstructed based on the CT data using Mimics software and computer aided design.