BACKGROUND:Fracture strength of the affected teeth after root canal therapy is often reduced due to the loss of healthy tooth tissues.How to enhance its fracture strength has always been an issue of concern for clinicians.Finite element analysis can visually show the stresses on various parts of the tooth in different states,and provide a comprehensive analysis of the tooth structure and the mechanical properties of materials.OBJECTIVE:To review the progress in the application of finite element analysis in endodontic root canal treatment of endodontic periapical disease and to look forward to the future development trend.METHODS:Literature related to the use of finite element analysis in root canal treatment of endodontic periapical disease was searched from foreign language databases(PubMed and Web of Science)and Chinese language databases(CNKI,WanFang,VIP,and China Biomedical Literature Service System).The search terms in English were"FEA,finite element analysis,stress analysis,root canal treatment,pulp opening,root canal preparation,root canal filling,restoration"and the search terms in Chinese were"finite element analysis,stress analysis,endodontic periapical disease,root canal treatment,pulp opening,root canal preparation,root canal filling,restoration."Finally,103 articles were included in the review.RESULTS AND CONCLUSION:Finite element analysis can be used to analyze the stress distribution and deformation of the tooth during mastication and occlusion by constructing a finite element model of the tooth and surrounding tissues.With the help of finite element analysis,clinical researchers can analyze the effects of different types of open cavities,root canal preparation methods,root canal filling materials and restorative solutions on the mechanical properties of the tooth body in the root canal treatment of endodontic periapical diseases,so as to select the optimal treatment plan that improves therapeutic outcomes and patient prognosis.Finite element analysis helps clinicians to reduce the loss of dental tissues in clinical treatment and improve the treatment effect and patient prognosis.The finite element model is a simplification of the actual situation and needs to be analyzed comprehensively in conjunction with clinical trials.

BACKGROUND:Fracture strength of the affected teeth after root canal therapy is often reduced due to the loss of healthy tooth tissues.How to enhance its fracture strength has always been an issue of concern for clinicians.Finite element analysis can visually show the stresses on various parts of the tooth in different states,and provide a comprehensive analysis of the tooth structure and the mechanical properties of materials.OBJECTIVE:To review the progress in the application of finite element analysis in endodontic root canal treatment of endodontic periapical disease and to look forward to the future development trend.METHODS:Literature related to the use of finite element analysis in root canal treatment of endodontic periapical disease was searched from foreign language databases(PubMed and Web of Science)and Chinese language databases(CNKI,WanFang,VIP,and China Biomedical Literature Service System).The search terms in English were"FEA,finite element analysis,stress analysis,root canal treatment,pulp opening,root canal preparation,root canal filling,restoration"and the search terms in Chinese were"finite element analysis,stress analysis,endodontic periapical disease,root canal treatment,pulp opening,root canal preparation,root canal filling,restoration."Finally,103 articles were included in the review.RESULTS AND CONCLUSION:Finite element analysis can be used to analyze the stress distribution and deformation of the tooth during mastication and occlusion by constructing a finite element model of the tooth and surrounding tissues.With the help of finite element analysis,clinical researchers can analyze the effects of different types of open cavities,root canal preparation methods,root canal filling materials and restorative solutions on the mechanical properties of the tooth body in the root canal treatment of endodontic periapical diseases,so as to select the optimal treatment plan that improves therapeutic outcomes and patient prognosis.Finite element analysis helps clinicians to reduce the loss of dental tissues in clinical treatment and improve the treatment effect and patient prognosis.The finite element model is a simplification of the actual situation and needs to be analyzed comprehensively in conjunction with clinical trials.

Mitochondria regulate numerous crucial cell processes, including energy production, apoptotic cell death, oxidative stress, calcium homeostasis and lipid metabolism. Here, we applied an efficient mitochondria-based centrifugal ultrafiltration/liquid chromatography/mass spectrometry (LC/MS) method,also known as screening method for mitochondria-targeted bioactive constituents (SM-MBC). This method allowed searching natural mitochondria-targeting compounds from traditional Chinese medicines(TCMs), including Puerariae Radix (PR) and Chuanxiong Radix (CR). A total of 23 active compounds were successfully discovered from the two TCMs extracts. Among these 23 hit compounds, 17 were identified by LC/MS, 12 of which were novel mitochondria-targeting compounds. Among these, 6 active compounds were analyzed in vitro for pharmacological tests and found able to affect mitochondrial functions. We also investigated the effects of the hit compounds on HepG2 cell proliferation and on loss of cardiomyocyte viability induced by hypoxia/reoxygenation injury. The results obtained are useful for in-depth understanding of mechanisms underlying TCMs therapeutic effects at mitochondria level and for developing novel potential drugs using TCMs as lead compounds. Finally, we showed that SM-MBC was an efficient protocol for the rapid screening of mitochondria-targeting constituents from complex samples such as PR and CR extracts.

Objective To compare the bonding strength of different adhesives to the enamel of mild, moderate and severe dental fluorosis with tensile bonding strength, and to provide the experimental foundation for choosing different adhesives for different degrees of dental fluorosis in clinical practice. Methods At the Affiliated Hospital of Inner Mongolia Medical University, according to the Dean classification standards, one hundred-eighty extracted caries-free and whole human premolars of dental fluorosis were divided into three groups with mild, moderate and severe degree,60 teeth in each group.Each group was divided into two subgroups by random number table method,30 teeth in each subgroup.The emery was used to remove enamel surface 0.5 mm,and then two kinds of bonding adhesives(all-etching adhesive prime&bond NT,self-etching adhesive SE-BOND) were used to bond, pressurized layered composite resin Z350 curing, kept in 37 ℃ distilled water for 24 h. The bonding strength was tested at universal material testing machine, and fracture interface was observated using scanning electron microscope. Results All-etching adhesive had statistical significant influence on the tensile strength of mild, moderate and severe dental fluorosis[(7.82 ± 4.20),(4.79 ± 2.69),(5.04 ± 2.81)MPa,F=4.610,P<0.05], and the tensile strength of mild dental fluorosis was the largest (P < 0.05), the tensile strength between moderate and severe dental fluorosis was not significantly different (P > 0.05). The effect of self-etching adhesive on the tensile strength of mild, moderate and severe dental fluorosis was not statistically significant (F = 0.393, P >0.05). The effect of all-etching adhesive on the tensile strength of mild dental fluorosis was stronger than that of self-etching adhesive(t = 2.197, P < 0.05). Under the scanning electron microscope,the enamel bonding surface of mild dental fluorosis was relatively uniform and compact,with a small amount of crystal disorder,crystal gap slightly widened; the enamel bonding surface of severe dental fluorosis lost seriously enamel, even some of the dentinal tubules exposed, with enamel relatively loose and non uniform, crystal disordered and crystal gap widened significantly, less number of enamel rod. Moderate dental fluorosis was similar to severe dental fluorosis; enamel stripping also occurred under the action of the pulling force but was slighter than severe dental fluorosis enamel. Conclusions ①The effect of all-etching adhesive on the tensile strength of mild dental fluorosis is stronger than that of self-etching adhesive. ②The effect of all-etching adhesive on the tensile strength of mild dental fluorosis is the biggest,there is no statistical significant difference between moderate and severe dental fluorosis.