To verify the theoretical models of varying transversely isotropic stress-strain relations of dentin established in the preceding work(Part Ⅰ),we per- form a set of experiments.Because of the very fine tooth size,it ...To verify the theoretical models of varying transversely isotropic stress-strain relations of dentin established in the preceding work(Part Ⅰ),we per- form a set of experiments.Because of the very fine tooth size,it usually seems to be difficult to directly measure the inhomogeneous and anisotropic parameters of dentin.In this paper,by the digital speckle correlation method,tensile experiments are made on the small dentin samples either parallel or perpendicular to the dentin tubules.With the theoretically predicted elastic stress-strain relations,an optimiza- tion method is proposed to fit the strain curve adapted to the experimental data. The results show that the theoretical elastic stress-strain relations coincides very well with the experimental observations.The determined Young's modulus and Poisson's ratio of dentin matrix are 29.5GPa and 0.44,respectively,in the optimization sense.展开更多
As known, there is a large number of dentin tubules in dentin. These tubules have varying radii and are shaped into radially parallel pattern. The anisotropy of microstructure of dentin shows that dentin should be tre...As known, there is a large number of dentin tubules in dentin. These tubules have varying radii and are shaped into radially parallel pattern. The anisotropy of microstructure of dentin shows that dentin should be treated as a ma- terial of varying transverse isotropy. In this Part, the elastic stress-strain relations and the quadratic strength criterion are established in the form of having varying transverse isotropy, in the framework of micromechanics to take into account of the effect of the microstructures-dentin tubules. Simplified forms for isotropic and ho- mogeneous cases, as well as the corresponding plane stress form of the stress-strain relations are also given. These theoretical models are very well supported by the experiments shown later in the continued paper (Part Ⅱ).展开更多
Dental pulp-dentin complex defects remain a major unresolved problem in oral medicines.Clinical therapeutic methods including root canal therapy and vital pulp therapy are both considered as conservative strategies,wh...Dental pulp-dentin complex defects remain a major unresolved problem in oral medicines.Clinical therapeutic methods including root canal therapy and vital pulp therapy are both considered as conservative strategies,which are incapable of repairing the pulpdentin complex defects.Although biomaterial-based strategies show remarkable progress in antibacterial,anti-inflammatory,and pulp regeneration,the important modulatory effects of nerves within pulp cavity have been greatly overlooked,making it challenging to achieve functional pulp-dentin complex regeneration.In this study,we propose an injectable bioceramicscontaining composite hydrogel in combination of Li-Ca-Si(LCS)bioceramics and gelatin methacrylate matrix with photocrosslinking properties.Due to the sustained release of bioactive Li,Ca and Si ions from LCS,the composite hydrogels possess multiple functions of promoting the neurogenic differentiation of Schwann cells,odontogenic differentiation of dental pulp stem cells,and neurogenesis-odontogenesis couples in vitro.In addition,the in vivo results showed that LCS-containing composite hydrogel can significantly promote the pulp-dentin complex repair.More importantly,LCS bioceramics-containing composite hydrogel can induce the growth of nerve fibers,leading to the re-innervation of pulp tissues.Taken together,the study suggests that LCS bioceramics can induce the innervation of pulp-dentin complex repair,offering a referable strategy of designing multifunctional filling materials for functional periodontal tissue regeneration.展开更多
背景:鱼类牙齿演化与发育研究是理解脊椎动物与人类牙齿的切入点。近年来,分子发育生物学技术的进步为揭示牙齿与鳞片的发育同源性及信号通路的作用提供了新视角,但不同物种的比较和演化机制整合仍需深化。目的:综述鱼类牙齿的演化起源...背景:鱼类牙齿演化与发育研究是理解脊椎动物与人类牙齿的切入点。近年来,分子发育生物学技术的进步为揭示牙齿与鳞片的发育同源性及信号通路的作用提供了新视角,但不同物种的比较和演化机制整合仍需深化。目的:综述鱼类牙齿的演化起源、形态差异及分子调控机制,对比不同假说的核心观点与局限性。方法:通过PubMed数据库和中国知网,以“fish teeth,tooth development,evolution of teeth,molecular regulation of teeth”为英文检索词,“鱼类牙齿,牙齿发育,牙齿演化,牙齿分子调控”为中文检索词,系统检索1970-2025年的相关文献,依据纳入标准,最终纳入77篇文献综合分析研究进展。结果与结论:分子发育证据支持“由外向内”修正假说,证实外胚层鳞片与内胚层间充质协同演化形成牙齿。鱼类牙本质划分为正齿型、骨齿型、假骨齿型及血管齿质4类。软骨鱼的类釉质依赖成牙本质细胞分泌管状囊泡启动矿化,而硬骨鱼类通过胶原纤维定向引导晶体生长,表明釉质矿化从囊泡主导向胶原模板的演化过渡。音猬因子信号在软骨鱼类中精确调控齿列再生位点,而斑马鱼咽齿依赖视黄酸信号时空特异性激活,证实核心通路(成纤维细胞生长因子、音猬因子、Wnt)的功能保守,但调控机制受到自然选择驱动,产生物种适应性演化。展开更多
目的比较两种含10-甲基丙烯酰氧基癸基二氢磷酸酯(10-Methacryloyldecylphosphate,10-MDP)的通用型粘接剂对老年患者的牙釉质、牙本质及硬化牙本质的粘接效果,为老年患者修复临床粘接剂的选择提供参考。方法选择因牙周炎拔除的完整无龋...目的比较两种含10-甲基丙烯酰氧基癸基二氢磷酸酯(10-Methacryloyldecylphosphate,10-MDP)的通用型粘接剂对老年患者的牙釉质、牙本质及硬化牙本质的粘接效果,为老年患者修复临床粘接剂的选择提供参考。方法选择因牙周炎拔除的完整无龋的老年患者离体前磨牙40颗,随机分为牙釉质组、牙本质组,每组20颗牙;另选取颈部楔状缺损,硬化牙本质达IV级的老年患者离体前磨牙20颗,为硬化牙本质组。每组各分为两个亚组(Single Bond Universal粘接剂亚组和美益汀粘接剂亚组),每亚组各10颗牙。选择离体牙颊侧牙面进行粘接面制备,3组Single Bond Universal粘接剂亚组离体牙使用Single Bond Universal粘接剂处理,3组美益汀粘接剂亚组使用美益汀粘接剂处理,分层充填复合树脂。万能力学试验机测试各组试件的微拉伸强度,在体视显微镜下分析各组试件的断裂模式。对两种粘接剂的微拉伸强度进行双因素方差分析,多重比较采用SNK-q检验;Kruskal-Wallis秩和检验比较两种粘接剂对牙釉质、牙本质及硬化牙本质断裂模式的影响。结果粘接强度结果表明,在牙釉质组、牙本质组以及硬化牙本质组,Single Bond Universal粘接剂与美益汀粘接剂都取得了临床可接受的粘接效果,且两种粘接剂对不同牙体硬组织粘接强度以及断裂模式差异无统计学意义(P>0.05)。结论含MDP的通用型粘接系统在老年患者牙釉质、牙本质以及硬化牙本质中的粘接表现具有等效性,本研究为老年高磨耗牙修复材料选择提供实验依据。展开更多
Our previous studies showed that biomodification of demineralized dentin collagen with proanthocyanidin（PA） for a clinically practical duration improves the mechanical properties of the dentin matrix and the immedia...Our previous studies showed that biomodification of demineralized dentin collagen with proanthocyanidin（PA） for a clinically practical duration improves the mechanical properties of the dentin matrix and the immediate resin–dentin bond strength. The present study sought to evaluate the ability of PA biomodification to reduce collagenase-induced biodegradation of demineralized dentin matrix and dentin/adhesive interfaces in a clinically relevant manner. The effects of collagenolytic and gelatinolytic activity on PA-biomodified demineralized dentin matrix were analysed by hydroxyproline assay and gelatin zymography. Then, resin-/dentin-bonded specimens were prepared and challenged with bacterial collagenases. Dentin treated with 2% chlorhexidine and untreated dentin were used as a positive and negative control, respectively. Collagen biodegradation, the microtensile bond strengths of bonded specimens and the micromorphologies of the fractured interfaces were assessed. The results revealed that both collagenolytic and gelatinolytic activity on demineralized dentin were notably inhibited in the PA-biomodified groups, irrespective of PA concentration and biomodification duration. When challenged with exogenous collagenases, PA-biomodified bonded specimens exhibited significantly less biodegradation and maintained higher bond strengths than the untreated control. These results suggest that PA biomodification was effective at inhibiting proteolytic activity on demineralized dentin matrix and at stabilizing the adhesive/dentin interface against enzymatic degradation, is a new concept that has the potential to improve bonding durability.展开更多
The aim of this study was to investigate the influence of ethylenediaminetetraacetic acid （EDTA） irrigation on demineralization rate of dentine located in the apical third of root canal walls. Teeth were divided int...The aim of this study was to investigate the influence of ethylenediaminetetraacetic acid （EDTA） irrigation on demineralization rate of dentine located in the apical third of root canal walls. Teeth were divided into A and B two groups. In group A, all of the teeth was irrigated with EDTA and NaOCI （sodium hypochlorite）, followed by cutting the apical third into slices longitudinally to examine the influence of EDTA on different portions of apical third of root canal. In group B, the apical third of a tooth was firstly cut into slices longitudinally, followed by coating the root canal walls with EDTA to in-situ observe the demineralization of dentine with different time. It was found that the influence of EDTA on root-canal was gradually increased from the apical to the upper end of the apical third for group A. In addition, the demineralization rate of dentine was remarkable in the first 25 min for group B. The diffusion of EDTA into root dentine would lead to potential damage to the dentine. Furthermore, demineralization rate curve was calculated.展开更多
Antibacterial dimethylaminododecyl methacrylate （DMADDM） was recently synthesized. The objectives of this study were to： （1） investigate antibacterial activity of DMADDM-containing primer on Streptococcus mutans ...Antibacterial dimethylaminododecyl methacrylate （DMADDM） was recently synthesized. The objectives of this study were to： （1） investigate antibacterial activity of DMADDM-containing primer on Streptococcus mutans impregnated into dentin blocks for the first time, and （2） compare the antibacterial efficacy of DMADDM with a previous quaternary ammonium dimethacrylate （QADM）. Scotchbond Multi-Purpose （SBMP） bonding agent was used. DMADDM and QADM were mixed into SBMP primer. Six primers were tested： SBMP control primer P, P＋2.5% DMADDM, P＋5% DMADDM, P＋7.5% DMADDM, P＋10% DMADDM, and P＋10% QADM. S. mutans were impregnated into human dentin blocks, and each primer was applied to dentin to test its ability to kill bacteria in dentinal tubules. Bacteria in dentin were collected via a sonication method, and the colony-forming units （CFU） and inhibition zones were measured. The bacterial inhibition zone of P＋10% DMADDM was 10 times that of control primer （P〈0.05）. CFU in dentin with P＋10% DMADDM was reduced by three orders of magnitude, compared with control. DMADDM had a much stronger antibacterial effect than QADM, and antibacterial efficacy increased with increasing DMADDM concentration. Dentin shear bond strengths were similar among all groups （P〉0.1）. In conclusion, antibacterial DMADDM-containing primer was validated to kill bacteria inside dentin blocks, possessing a much stronger antibacterial potency than the previous QADM. DMADDM-containing bonding agent was effective in eradicating bacteria in dentin, and its efficacy was directly proportional to DMADDM mass fraction. Therefore, DMADDM may be promisine for use in bonding agents as well as in other restorative and oreventive materials to inhibit bacteria.展开更多
Phosphophoryn (PP) and dentin sialoprotein (DSP) are the most dominant non-collagenous proteins in dentin. PP is an extremely acidic protein that can function as a mineral nucleator for dentin mineralization. DSP was ...Phosphophoryn (PP) and dentin sialoprotein (DSP) are the most dominant non-collagenous proteins in dentin. PP is an extremely acidic protein that can function as a mineral nucleator for dentin mineralization. DSP was first identified in 1981, yet its functional significance is still controversial. Historically, these two proteins were considered to be independently synthesized and secreted by dental pulp cells into the developing dentin matrix. However, with the identification of the DSP coding sequence in 1994, followed2 years later by the finding that the PP coding sequence was located immediately downstream from the DSP sequence, it became immediately clear that DSP and PP proteins were derived from a single DSP-PP (i.e., dentin sialophosphoprotein, DSPP) transcript.Since DSPP cDNA became available, tremendous progress has been made in studying DSP-PP mRNA distribution and DSP generation from the DSP-PP precursor protein at specific cleavage sites by protease tolloid-related-1 (TLR1) or bone morphogenetic protein 1 (BMP1). The functions of DSP-PP and DSP were investigated via DSP-PP knockout (KO) and DSP knockin in DSP-PP KO mice. In addition, a number of in vitro studies aimed to elucidate DSPP and DSP function in dental pulp cells.展开更多
AIM: To systematically review the literature on the efficacy of noninvasive methods of arresting the progression of non-cavitated occlusal carious lesions in dentin.METHODS: The Medline/Pub Med,LILACS,Sci ELO and Scop...AIM: To systematically review the literature on the efficacy of noninvasive methods of arresting the progression of non-cavitated occlusal carious lesions in dentin.METHODS: The Medline/Pub Med,LILACS,Sci ELO and Scopus databases were searched to identify relevant publications through to November 2013.Only clinical trials evaluating the ability of noninvasive methods to arrest the progression of occlusal non-cavitated carious lesions in dentin were included.Screening,data extraction and quality assessment were conducted independently and in duplicate.RESULTS: Of 167 citations identified,nine full text articles were screened and five were included in the analysis.All papers reported on occlusal fissure sealing using a self-curing glass ionomer(n = 1) or resin-based(n = 4) sealant.Only the use of resin-based sealant to obliterate occlusal fissures arrested the progression of non-cavitated occlusal carious lesions in dentin.CONCLUSION: Occlusal fissure sealing with a resin-based sealant may arrest the progression of non-cavitated occlusal dentinal caries.Further clinical trials with longer follow-up times should be performed to increase scientific evidence.展开更多
Deletion or mutation of dentin matrix protein 1 （DMP1） leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indir...Deletion or mutation of dentin matrix protein 1 （DMP1） leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indirect role of phosphate （Pi） or both. It has also been previously shown that Klotho-deficient mice, which displayed a high Pi level due to a failure of Pi excretion, causes mild defects in the dentinal structure. This study was to address the distinct roles of DMP1 and Pi homeostasis in cell differentiation, apoptosis and mineralization of dentin and enamel. Our working hypothesis was that a stable Pi homeostasis is critical for postnatal tooth formation, and that DMP1 has an antiapoptotic role in both amelogenesis and dentinogenesis. To test this hypothesis, Dmpl-null （Dmpl-/-）, Klotho-deficient （kl/kl）, Dmpl/Klotho-double-deficient （Dmpl-/-/kl/kl） and wild-type （WT） mice were killed at the age of 6 weeks. Combinations of X-ray, microcomputed tomography （I^CT）, scanning electron microscopy （SEM）, histology, apoptosis and immunohistochemical methods were used for characterization of dentin, enamel and pulp structures in these mutant mice. Our results showed that Dmpl-/- （a low Pi level） or kl/kl（a high Pi level） mice displayed mild dentin defects such as thin dentin and a reduction of dentin tubules. Neither deficient mouse line exhibited any apparent changes in enamel or pulp structure. However, the double-deficient mice （a high Pi level） displayed severe defects in dentin and enamel structures, including loss of dentinal tubules and enamel prisms, as well as unexpected ectopic ossification within the pulp root canal. TUNEL assay showed a sharp increase in apoptotic cells in ameloblasts and odontoblasts. Based on the above findings, we conclude that DMP1 has a protective role for odontoblasts and ameloblasts in a pro-apoptotic environment （a high Pi level）.展开更多
Objective To investigate the effect of multiple coatings of the one-step self-etching adhesive on immediate microtensile bond strength to primary dentin.Methods Twelve caries-free human primary molars were randomly di...Objective To investigate the effect of multiple coatings of the one-step self-etching adhesive on immediate microtensile bond strength to primary dentin.Methods Twelve caries-free human primary molars were randomly divided into 2 groups with 6 teeth each.In group 1,each tooth was hemisected into two halves.One half was assigned to control subgroup 1,which was bonded with a single-step self-etching adhesive according to the manufacturer's instructions;the other half was assigned to experimental subgroup 1 in which the adhesive was applied three times before light curing.In group 2,the teeth were also hemisected into two halves.One half was assigned to control subgroup 2,which was bonded with the single-step self-etching adhesive according to the manufacturer's instructions;the other half was assigned to experimental subgroup 2 in which three layers of adhesive were applied with light curing each successive layer.Microtensile bond strength was immediately tested after specimen preparation.Results When the adhesive was applied three times before light curing,the bond strength of the experimental subgroup 1(n=33,57.49±11.61 MPa) was higher than that of the control subgroup 1(n=31,49.71±11.43 MPa,P<0.05).When using the technique of applying multiple layers of adhesive with light curing each successive layer,no difference of immediate bond strength was observed between the control subgroup 2 and the experimental subgroup 2(P>0.05).Conclusion Multiple coatings of one-step self-etching adhesive can increase the immediate bond strength to primary dentin when using the technique of light-curing after applying three layers of adhesive.展开更多
In this study, we employed a nonthermal atmospheric pressure plasma(NTAPP) jet to evaluate the effect of plasma treatment on the durability of resin–dentin bonding under a thermocycling challenge. Furthermore, we ass...In this study, we employed a nonthermal atmospheric pressure plasma(NTAPP) jet to evaluate the effect of plasma treatment on the durability of resin–dentin bonding under a thermocycling challenge. Furthermore, we assessed the degradation resistance of plasma-treated collagen under a sodium hypochlorite(NaClO) challenge. We assessed the beneficial effect of NTAPP treatment on the acid-etched dentin–bonding interface by testing the micro-tensile bond strength and examining the morphology. We found that the immediate bonding strength of the dentin significantly increased after NTAPP treatment. Compared with the control group, NTAPP resulted in a more prominent effect on the bonding durability of the dentin–adhesive interface after treatment for 5 or 10 s. Simultaneously, the mechanical strength of dentin collagen under the NaClO challenge was improved. Our results indicate that, in optimal conditions, NTAPP could be a promising method to protect dentin collagen and to improve the bonding durability between dentin and etch-and-rinse adhesives.展开更多
The aim of this study is to investigate the change of mechanical properties of human dentin due to aging and spatial variation. Sections of coronal dentin are made from human molars in three groups： young, mid-aged, ...The aim of this study is to investigate the change of mechanical properties of human dentin due to aging and spatial variation. Sections of coronal dentin are made from human molars in three groups： young, mid-aged, and old patients. A nanoindentation test is conducted from regions near the pulp to the dentin-enamel junction （DE J） to evaluate the load-depth indentation response and determine Young＇s modulus and hardness. Based on the loading and unloading load-displacement curves in nanoindentation, a numerical model of plastic damage is used to study the plastic and the damage behaviors and the contribution to the degradation in the unloading stiffness. The experimental results show that Young＇s modulus of the inner dentin is significantly lower than that of outer dentin in each age group. Compared with the young dentin, the old dentin has greater hardness and Young＇s modulus with similar spatial variations. The magnitudes of the yield strength and the damage variable are also affected by aging and vary with spatial locations. In the same age group, the yield strength in inner dentin is lower than those in middle and outer dentin, more damage occurs with similar spatial variations, and the yield strength of young dentin is generally lower and causes more damage compared with those in both the mid-aged and old groups.展开更多
基金The project supported by the National Natural Science Foundation of China(19525207)
文摘To verify the theoretical models of varying transversely isotropic stress-strain relations of dentin established in the preceding work(Part Ⅰ),we per- form a set of experiments.Because of the very fine tooth size,it usually seems to be difficult to directly measure the inhomogeneous and anisotropic parameters of dentin.In this paper,by the digital speckle correlation method,tensile experiments are made on the small dentin samples either parallel or perpendicular to the dentin tubules.With the theoretically predicted elastic stress-strain relations,an optimiza- tion method is proposed to fit the strain curve adapted to the experimental data. The results show that the theoretical elastic stress-strain relations coincides very well with the experimental observations.The determined Young's modulus and Poisson's ratio of dentin matrix are 29.5GPa and 0.44,respectively,in the optimization sense.
基金The project supported by the National Natural Science Foundation of China (19525207).
文摘As known, there is a large number of dentin tubules in dentin. These tubules have varying radii and are shaped into radially parallel pattern. The anisotropy of microstructure of dentin shows that dentin should be treated as a ma- terial of varying transverse isotropy. In this Part, the elastic stress-strain relations and the quadratic strength criterion are established in the form of having varying transverse isotropy, in the framework of micromechanics to take into account of the effect of the microstructures-dentin tubules. Simplified forms for isotropic and ho- mogeneous cases, as well as the corresponding plane stress form of the stress-strain relations are also given. These theoretical models are very well supported by the experiments shown later in the continued paper (Part Ⅱ).
基金funded by the National Key R&D Program of China(2022YFC2405904)the National Natural Science Foundation of China(52272284,32225028)+1 种基金Joint Research Unit Plan of the Chinese Academy of Sciences(121631ZYLH20240014)the Science and Technology Commission of Shanghai Municipality(24520750100)。
文摘Dental pulp-dentin complex defects remain a major unresolved problem in oral medicines.Clinical therapeutic methods including root canal therapy and vital pulp therapy are both considered as conservative strategies,which are incapable of repairing the pulpdentin complex defects.Although biomaterial-based strategies show remarkable progress in antibacterial,anti-inflammatory,and pulp regeneration,the important modulatory effects of nerves within pulp cavity have been greatly overlooked,making it challenging to achieve functional pulp-dentin complex regeneration.In this study,we propose an injectable bioceramicscontaining composite hydrogel in combination of Li-Ca-Si(LCS)bioceramics and gelatin methacrylate matrix with photocrosslinking properties.Due to the sustained release of bioactive Li,Ca and Si ions from LCS,the composite hydrogels possess multiple functions of promoting the neurogenic differentiation of Schwann cells,odontogenic differentiation of dental pulp stem cells,and neurogenesis-odontogenesis couples in vitro.In addition,the in vivo results showed that LCS-containing composite hydrogel can significantly promote the pulp-dentin complex repair.More importantly,LCS bioceramics-containing composite hydrogel can induce the growth of nerve fibers,leading to the re-innervation of pulp tissues.Taken together,the study suggests that LCS bioceramics can induce the innervation of pulp-dentin complex repair,offering a referable strategy of designing multifunctional filling materials for functional periodontal tissue regeneration.
文摘背景:鱼类牙齿演化与发育研究是理解脊椎动物与人类牙齿的切入点。近年来,分子发育生物学技术的进步为揭示牙齿与鳞片的发育同源性及信号通路的作用提供了新视角,但不同物种的比较和演化机制整合仍需深化。目的:综述鱼类牙齿的演化起源、形态差异及分子调控机制,对比不同假说的核心观点与局限性。方法:通过PubMed数据库和中国知网,以“fish teeth,tooth development,evolution of teeth,molecular regulation of teeth”为英文检索词,“鱼类牙齿,牙齿发育,牙齿演化,牙齿分子调控”为中文检索词,系统检索1970-2025年的相关文献,依据纳入标准,最终纳入77篇文献综合分析研究进展。结果与结论:分子发育证据支持“由外向内”修正假说,证实外胚层鳞片与内胚层间充质协同演化形成牙齿。鱼类牙本质划分为正齿型、骨齿型、假骨齿型及血管齿质4类。软骨鱼的类釉质依赖成牙本质细胞分泌管状囊泡启动矿化,而硬骨鱼类通过胶原纤维定向引导晶体生长,表明釉质矿化从囊泡主导向胶原模板的演化过渡。音猬因子信号在软骨鱼类中精确调控齿列再生位点,而斑马鱼咽齿依赖视黄酸信号时空特异性激活,证实核心通路(成纤维细胞生长因子、音猬因子、Wnt)的功能保守,但调控机制受到自然选择驱动,产生物种适应性演化。
文摘目的比较两种含10-甲基丙烯酰氧基癸基二氢磷酸酯(10-Methacryloyldecylphosphate,10-MDP)的通用型粘接剂对老年患者的牙釉质、牙本质及硬化牙本质的粘接效果,为老年患者修复临床粘接剂的选择提供参考。方法选择因牙周炎拔除的完整无龋的老年患者离体前磨牙40颗,随机分为牙釉质组、牙本质组,每组20颗牙;另选取颈部楔状缺损,硬化牙本质达IV级的老年患者离体前磨牙20颗,为硬化牙本质组。每组各分为两个亚组(Single Bond Universal粘接剂亚组和美益汀粘接剂亚组),每亚组各10颗牙。选择离体牙颊侧牙面进行粘接面制备,3组Single Bond Universal粘接剂亚组离体牙使用Single Bond Universal粘接剂处理,3组美益汀粘接剂亚组使用美益汀粘接剂处理,分层充填复合树脂。万能力学试验机测试各组试件的微拉伸强度,在体视显微镜下分析各组试件的断裂模式。对两种粘接剂的微拉伸强度进行双因素方差分析,多重比较采用SNK-q检验;Kruskal-Wallis秩和检验比较两种粘接剂对牙釉质、牙本质及硬化牙本质断裂模式的影响。结果粘接强度结果表明,在牙釉质组、牙本质组以及硬化牙本质组,Single Bond Universal粘接剂与美益汀粘接剂都取得了临床可接受的粘接效果,且两种粘接剂对不同牙体硬组织粘接强度以及断裂模式差异无统计学意义(P>0.05)。结论含MDP的通用型粘接系统在老年患者牙釉质、牙本质以及硬化牙本质中的粘接表现具有等效性,本研究为老年高磨耗牙修复材料选择提供实验依据。
基金supported by research funds from the Natural Science Foundation of China (No. 81130078 and No. 81000458)Program for Changjiang Scholars and Innovative Research Team in University (No. IRT13051)
文摘Our previous studies showed that biomodification of demineralized dentin collagen with proanthocyanidin（PA） for a clinically practical duration improves the mechanical properties of the dentin matrix and the immediate resin–dentin bond strength. The present study sought to evaluate the ability of PA biomodification to reduce collagenase-induced biodegradation of demineralized dentin matrix and dentin/adhesive interfaces in a clinically relevant manner. The effects of collagenolytic and gelatinolytic activity on PA-biomodified demineralized dentin matrix were analysed by hydroxyproline assay and gelatin zymography. Then, resin-/dentin-bonded specimens were prepared and challenged with bacterial collagenases. Dentin treated with 2% chlorhexidine and untreated dentin were used as a positive and negative control, respectively. Collagen biodegradation, the microtensile bond strengths of bonded specimens and the micromorphologies of the fractured interfaces were assessed. The results revealed that both collagenolytic and gelatinolytic activity on demineralized dentin were notably inhibited in the PA-biomodified groups, irrespective of PA concentration and biomodification duration. When challenged with exogenous collagenases, PA-biomodified bonded specimens exhibited significantly less biodegradation and maintained higher bond strengths than the untreated control. These results suggest that PA biomodification was effective at inhibiting proteolytic activity on demineralized dentin matrix and at stabilizing the adhesive/dentin interface against enzymatic degradation, is a new concept that has the potential to improve bonding durability.
基金the financial support of the project from the Foundation of the Education Department of Liaoning Province(Grant No.L2013285)Science and Technology Planning Project of Shenyang City(Grant No.F11262-9-16)
文摘The aim of this study was to investigate the influence of ethylenediaminetetraacetic acid （EDTA） irrigation on demineralization rate of dentine located in the apical third of root canal walls. Teeth were divided into A and B two groups. In group A, all of the teeth was irrigated with EDTA and NaOCI （sodium hypochlorite）, followed by cutting the apical third into slices longitudinally to examine the influence of EDTA on different portions of apical third of root canal. In group B, the apical third of a tooth was firstly cut into slices longitudinally, followed by coating the root canal walls with EDTA to in-situ observe the demineralization of dentine with different time. It was found that the influence of EDTA on root-canal was gradually increased from the apical to the upper end of the apical third for group A. In addition, the demineralization rate of dentine was remarkable in the first 25 min for group B. The diffusion of EDTA into root dentine would lead to potential damage to the dentine. Furthermore, demineralization rate curve was calculated.
基金supported by NIH R01 DE17974 (Hockin HK Xu)a scholarship from West China School of Stomatology (Chen Chen)+3 种基金Program for New Century Excellent Talents in University (Lei Cheng)Youth Grant of Science and Technology Department of Sichuan Province China (2014JQ0033) (Lei Cheng)a bridge fund from University of Maryland Baltimore School of Dentistry (Hockin HK Xu)a seed grant from University of Maryland Baltimore (Hockin HK Xu)
文摘Antibacterial dimethylaminododecyl methacrylate （DMADDM） was recently synthesized. The objectives of this study were to： （1） investigate antibacterial activity of DMADDM-containing primer on Streptococcus mutans impregnated into dentin blocks for the first time, and （2） compare the antibacterial efficacy of DMADDM with a previous quaternary ammonium dimethacrylate （QADM）. Scotchbond Multi-Purpose （SBMP） bonding agent was used. DMADDM and QADM were mixed into SBMP primer. Six primers were tested： SBMP control primer P, P＋2.5% DMADDM, P＋5% DMADDM, P＋7.5% DMADDM, P＋10% DMADDM, and P＋10% QADM. S. mutans were impregnated into human dentin blocks, and each primer was applied to dentin to test its ability to kill bacteria in dentinal tubules. Bacteria in dentin were collected via a sonication method, and the colony-forming units （CFU） and inhibition zones were measured. The bacterial inhibition zone of P＋10% DMADDM was 10 times that of control primer （P〈0.05）. CFU in dentin with P＋10% DMADDM was reduced by three orders of magnitude, compared with control. DMADDM had a much stronger antibacterial effect than QADM, and antibacterial efficacy increased with increasing DMADDM concentration. Dentin shear bond strengths were similar among all groups （P〉0.1）. In conclusion, antibacterial DMADDM-containing primer was validated to kill bacteria inside dentin blocks, possessing a much stronger antibacterial potency than the previous QADM. DMADDM-containing bonding agent was effective in eradicating bacteria in dentin, and its efficacy was directly proportional to DMADDM mass fraction. Therefore, DMADDM may be promisine for use in bonding agents as well as in other restorative and oreventive materials to inhibit bacteria.
文摘Phosphophoryn (PP) and dentin sialoprotein (DSP) are the most dominant non-collagenous proteins in dentin. PP is an extremely acidic protein that can function as a mineral nucleator for dentin mineralization. DSP was first identified in 1981, yet its functional significance is still controversial. Historically, these two proteins were considered to be independently synthesized and secreted by dental pulp cells into the developing dentin matrix. However, with the identification of the DSP coding sequence in 1994, followed2 years later by the finding that the PP coding sequence was located immediately downstream from the DSP sequence, it became immediately clear that DSP and PP proteins were derived from a single DSP-PP (i.e., dentin sialophosphoprotein, DSPP) transcript.Since DSPP cDNA became available, tremendous progress has been made in studying DSP-PP mRNA distribution and DSP generation from the DSP-PP precursor protein at specific cleavage sites by protease tolloid-related-1 (TLR1) or bone morphogenetic protein 1 (BMP1). The functions of DSP-PP and DSP were investigated via DSP-PP knockout (KO) and DSP knockin in DSP-PP KO mice. In addition, a number of in vitro studies aimed to elucidate DSPP and DSP function in dental pulp cells.
文摘AIM: To systematically review the literature on the efficacy of noninvasive methods of arresting the progression of non-cavitated occlusal carious lesions in dentin.METHODS: The Medline/Pub Med,LILACS,Sci ELO and Scopus databases were searched to identify relevant publications through to November 2013.Only clinical trials evaluating the ability of noninvasive methods to arrest the progression of occlusal non-cavitated carious lesions in dentin were included.Screening,data extraction and quality assessment were conducted independently and in duplicate.RESULTS: Of 167 citations identified,nine full text articles were screened and five were included in the analysis.All papers reported on occlusal fissure sealing using a self-curing glass ionomer(n = 1) or resin-based(n = 4) sealant.Only the use of resin-based sealant to obliterate occlusal fissures arrested the progression of non-cavitated occlusal carious lesions in dentin.CONCLUSION: Occlusal fissure sealing with a resin-based sealant may arrest the progression of non-cavitated occlusal dentinal caries.Further clinical trials with longer follow-up times should be performed to increase scientific evidence.
基金supported by NIH grants Jian-Quan Feng (DE018486) and to Chun-Lin Qin (DE005092)State Key Laboratory of Oral Diseases Open Funding (SKLODOF2010-03) to Jian-Quan Feng
文摘Deletion or mutation of dentin matrix protein 1 （DMP1） leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indirect role of phosphate （Pi） or both. It has also been previously shown that Klotho-deficient mice, which displayed a high Pi level due to a failure of Pi excretion, causes mild defects in the dentinal structure. This study was to address the distinct roles of DMP1 and Pi homeostasis in cell differentiation, apoptosis and mineralization of dentin and enamel. Our working hypothesis was that a stable Pi homeostasis is critical for postnatal tooth formation, and that DMP1 has an antiapoptotic role in both amelogenesis and dentinogenesis. To test this hypothesis, Dmpl-null （Dmpl-/-）, Klotho-deficient （kl/kl）, Dmpl/Klotho-double-deficient （Dmpl-/-/kl/kl） and wild-type （WT） mice were killed at the age of 6 weeks. Combinations of X-ray, microcomputed tomography （I^CT）, scanning electron microscopy （SEM）, histology, apoptosis and immunohistochemical methods were used for characterization of dentin, enamel and pulp structures in these mutant mice. Our results showed that Dmpl-/- （a low Pi level） or kl/kl（a high Pi level） mice displayed mild dentin defects such as thin dentin and a reduction of dentin tubules. Neither deficient mouse line exhibited any apparent changes in enamel or pulp structure. However, the double-deficient mice （a high Pi level） displayed severe defects in dentin and enamel structures, including loss of dentinal tubules and enamel prisms, as well as unexpected ectopic ossification within the pulp root canal. TUNEL assay showed a sharp increase in apoptotic cells in ameloblasts and odontoblasts. Based on the above findings, we conclude that DMP1 has a protective role for odontoblasts and ameloblasts in a pro-apoptotic environment （a high Pi level）.
文摘Objective To investigate the effect of multiple coatings of the one-step self-etching adhesive on immediate microtensile bond strength to primary dentin.Methods Twelve caries-free human primary molars were randomly divided into 2 groups with 6 teeth each.In group 1,each tooth was hemisected into two halves.One half was assigned to control subgroup 1,which was bonded with a single-step self-etching adhesive according to the manufacturer's instructions;the other half was assigned to experimental subgroup 1 in which the adhesive was applied three times before light curing.In group 2,the teeth were also hemisected into two halves.One half was assigned to control subgroup 2,which was bonded with the single-step self-etching adhesive according to the manufacturer's instructions;the other half was assigned to experimental subgroup 2 in which three layers of adhesive were applied with light curing each successive layer.Microtensile bond strength was immediately tested after specimen preparation.Results When the adhesive was applied three times before light curing,the bond strength of the experimental subgroup 1(n=33,57.49±11.61 MPa) was higher than that of the control subgroup 1(n=31,49.71±11.43 MPa,P<0.05).When using the technique of applying multiple layers of adhesive with light curing each successive layer,no difference of immediate bond strength was observed between the control subgroup 2 and the experimental subgroup 2(P>0.05).Conclusion Multiple coatings of one-step self-etching adhesive can increase the immediate bond strength to primary dentin when using the technique of light-curing after applying three layers of adhesive.
基金supported by grants from National Natural Science Foundation of China(Nos.81701014,81801310,31700076)the Basic Research of Natural Science Project funded by the Department of Science and Technology of Shaanxi Province(No.2017JM8038)the Science and Technology Project funded by the Science and Technology Bureau of Weiyang District,Xi’an city(No.201846)。
文摘In this study, we employed a nonthermal atmospheric pressure plasma(NTAPP) jet to evaluate the effect of plasma treatment on the durability of resin–dentin bonding under a thermocycling challenge. Furthermore, we assessed the degradation resistance of plasma-treated collagen under a sodium hypochlorite(NaClO) challenge. We assessed the beneficial effect of NTAPP treatment on the acid-etched dentin–bonding interface by testing the micro-tensile bond strength and examining the morphology. We found that the immediate bonding strength of the dentin significantly increased after NTAPP treatment. Compared with the control group, NTAPP resulted in a more prominent effect on the bonding durability of the dentin–adhesive interface after treatment for 5 or 10 s. Simultaneously, the mechanical strength of dentin collagen under the NaClO challenge was improved. Our results indicate that, in optimal conditions, NTAPP could be a promising method to protect dentin collagen and to improve the bonding durability between dentin and etch-and-rinse adhesives.
基金supported by the National Natural Science Foundation of China(Nos.11172161 and11372173)the Innovation Program of Shanghai Municipal Education Commission(No.12ZZ092)+1 种基金the China Postdoctoral Science Foundation(No.2013M541504)the Shanghai Leading Academic Discipline Project(No.S30106)
文摘The aim of this study is to investigate the change of mechanical properties of human dentin due to aging and spatial variation. Sections of coronal dentin are made from human molars in three groups： young, mid-aged, and old patients. A nanoindentation test is conducted from regions near the pulp to the dentin-enamel junction （DE J） to evaluate the load-depth indentation response and determine Young＇s modulus and hardness. Based on the loading and unloading load-displacement curves in nanoindentation, a numerical model of plastic damage is used to study the plastic and the damage behaviors and the contribution to the degradation in the unloading stiffness. The experimental results show that Young＇s modulus of the inner dentin is significantly lower than that of outer dentin in each age group. Compared with the young dentin, the old dentin has greater hardness and Young＇s modulus with similar spatial variations. The magnitudes of the yield strength and the damage variable are also affected by aging and vary with spatial locations. In the same age group, the yield strength in inner dentin is lower than those in middle and outer dentin, more damage occurs with similar spatial variations, and the yield strength of young dentin is generally lower and causes more damage compared with those in both the mid-aged and old groups.
