Human dental hard tissues are dentine, cementum, and enamel. These are hydrated mineralised composite tissues with a hierarchical structure and versatile thermo-mechanical properties. The hierarchical structure of den...Human dental hard tissues are dentine, cementum, and enamel. These are hydrated mineralised composite tissues with a hierarchical structure and versatile thermo-mechanical properties. The hierarchical structure of dentine and enamel was imaged by transmission electron microscopy （TEM） of samples prepared by focused ion beam （FIB） milling. High resolution TEM was carried out in the vicinity of a crack tip in dentine. An intricate ＂random weave＂ pattern of hydroxyapatile crystallites was observed and this provided a possible explanation for toughening of the mineralized dentine tissue at the nano-scale. The results reported here provide the basis for improved understanding of the rela- tionship between the multi-scale nature and the mechanical properties of hierarchically structured biomaterials, and will also be useful for the development of better prosthetic and dental restorative materials.展开更多
It is observed that there is not enough literature to support the usefulness of dental tissue in forensic medicine for the estimation of postmortem interval(PMI).Therefore,the authors of this article have systematical...It is observed that there is not enough literature to support the usefulness of dental tissue in forensic medicine for the estimation of postmortem interval(PMI).Therefore,the authors of this article have systematically reviewed the available literature to understand the most used dental tissues,the methods employed to evaluate these tissues,and their reliability in PMI estimation.A MEDLINE-PubMed search engine was used to review the literature using the keywords“teeth,”“dental tissues,”“post‑mortem interval,”and“forensic dentistry”from 2001 until 2020.The most used tissue was dental pulp,but other cellular‑.and molecular‑level dental tissues such as enamel,dentin,cementum,periodontal ligament,odontoblast,and mitochondrial and nuclear DNA and RNA were also used.Based on this observation,the authors have provided the categorical classification to evaluate these dental tissues into morphological,histopathological,and molecular‑level examination to understand the reliability of these dental tissues.The molecular examinations to evaluate these tissues were widely employed and emerging in the estimation of PMI as this method could provide a reliable outcome when compared with others.Since the literature reviewed was not enough to answer our questions,however,to conclude,the dental pulp is the widely used tissue so far.Further,more studies are required to authenticate the role of other dental tissues to predict the PMI at an early stage with cost‑effective and most convenient techniques.展开更多
A new facile route for preparation of β-TCP/PLLA composites is reported in this letter. SEM images display that β-TCP particles with average diameter of 400 nm were well bonded and distributed within the pore walls ...A new facile route for preparation of β-TCP/PLLA composites is reported in this letter. SEM images display that β-TCP particles with average diameter of 400 nm were well bonded and distributed within the pore walls of the PLLA scaffolds. The mixture of the novel complex and human dental pulp cells was transplanted subcutaneously into the dorsal surface of a nude mouse. Two months later histological examination showed that new collagen and new dentin formed. The results revealed that the new nano β-TCP/PLLA composite combined with human pulp cells could induce dentin formation offering a new way to dental tissue engineering.展开更多
基金supported by EPSRC through grants"Multi-disciplinary Centre for In-situ Processing Studies(CIPS)"(EP/I020691),"Micromechanical Modelling and Experimentation"(EP/G004676),and "New Dimensions of Engineering Science at Large Facilities"(EP/H003215)
文摘Human dental hard tissues are dentine, cementum, and enamel. These are hydrated mineralised composite tissues with a hierarchical structure and versatile thermo-mechanical properties. The hierarchical structure of dentine and enamel was imaged by transmission electron microscopy （TEM） of samples prepared by focused ion beam （FIB） milling. High resolution TEM was carried out in the vicinity of a crack tip in dentine. An intricate ＂random weave＂ pattern of hydroxyapatile crystallites was observed and this provided a possible explanation for toughening of the mineralized dentine tissue at the nano-scale. The results reported here provide the basis for improved understanding of the rela- tionship between the multi-scale nature and the mechanical properties of hierarchically structured biomaterials, and will also be useful for the development of better prosthetic and dental restorative materials.
文摘It is observed that there is not enough literature to support the usefulness of dental tissue in forensic medicine for the estimation of postmortem interval(PMI).Therefore,the authors of this article have systematically reviewed the available literature to understand the most used dental tissues,the methods employed to evaluate these tissues,and their reliability in PMI estimation.A MEDLINE-PubMed search engine was used to review the literature using the keywords“teeth,”“dental tissues,”“post‑mortem interval,”and“forensic dentistry”from 2001 until 2020.The most used tissue was dental pulp,but other cellular‑.and molecular‑level dental tissues such as enamel,dentin,cementum,periodontal ligament,odontoblast,and mitochondrial and nuclear DNA and RNA were also used.Based on this observation,the authors have provided the categorical classification to evaluate these dental tissues into morphological,histopathological,and molecular‑level examination to understand the reliability of these dental tissues.The molecular examinations to evaluate these tissues were widely employed and emerging in the estimation of PMI as this method could provide a reliable outcome when compared with others.Since the literature reviewed was not enough to answer our questions,however,to conclude,the dental pulp is the widely used tissue so far.Further,more studies are required to authenticate the role of other dental tissues to predict the PMI at an early stage with cost‑effective and most convenient techniques.
基金We gratefully acknowledge the support of this research work by National High Technology Research and Development Program of China （No. 2003AA302220, 2004AA304G50）the National Natural Science Foundation of China （No. 30471907）.
文摘A new facile route for preparation of β-TCP/PLLA composites is reported in this letter. SEM images display that β-TCP particles with average diameter of 400 nm were well bonded and distributed within the pore walls of the PLLA scaffolds. The mixture of the novel complex and human dental pulp cells was transplanted subcutaneously into the dorsal surface of a nude mouse. Two months later histological examination showed that new collagen and new dentin formed. The results revealed that the new nano β-TCP/PLLA composite combined with human pulp cells could induce dentin formation offering a new way to dental tissue engineering.
