Evidence of generalised mechanical hyperalgesia in patients with advanced knee osteoarthritis undergoing total knee arthroplasty

Background and objective

Persistent pain is reported in up to 34% of patients following total knee arthroplasty (TKA) for management of knee osteoarthritis (KOA). Persistent pain in this group is thought to be at least partly reflective of pain sensory hypersensitivity. The objective of this study was to evaluate sensory hypersensitivity, using mechanical and thermal quantitative sensory testing, in patients about to undergo TKA.

Protein tyrosine phosphatase conjugated with a novel transdermal delivery peptide,astrotactin 1–derived peptide recombinant protein tyrosine phosphatase (AP-rPTP), alleviates both atopic dermatitis–like and psoriasis-like dermatitis

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Concentration-dependent Effect of Sodium Hypochlorite on Stem Cells of Apical Papilla Survival and Differentiation

Introduction

Intracanal disinfection is a crucial step in regenerative endodontic procedures. Most published cases suggest the use of sodium hypochlorite (NaOCl) as the primary irrigant. However, the effect of clinically used concentrations of NaOCl on the survival and differentiation of stem cells is largely unknown. In this study, we tested the effect of various concentrations of NaOCl on the stem cells of the apical papilla (SCAPs) survival and dentin sialophosphoprotein (DSPP) expression.

Methods

Standardized root canals were created in extracted human teeth and irrigated with NaOCl (0.5%, 1.5%, 3%, or 6%) followed by 17% EDTA or sterile saline. SCAPs in a hyaluronic acid–based scaffold were seeded into the canals and cultured for 7 days. Next, viable cells were quantified using a luminescence assay, and DSPP expression was evaluated using quantitative real-time polymerase chain reaction.

Results

There was a significant reduction in survival and DSPP expression in the group treated with 6% NaOCl compared with the untreated control group. Comparable survival was observed in the groups treated with the lower concentrations of NaOCl, but greater DSPP expression was observed in the 1.5% NaOCl group. In addition, 17% EDTA resulted in increased survival and DSPP expression partially reversing the deleterious effects of NaOCl.

Conclusions

Collectively, the results suggest that dentin conditioning with high concentrations of NaOCl has a profound negative effect on the survival and differentiation of SCAPs. However, this effect can be prevented with the use of 1.5% NaOCl followed by 17% EDTA. The inclusion of this irrigation regimen might be beneficial in regenerative endodontic procedures.     

Remineralization potential of fully demineralized dentin infiltrated with silica and hydroxyapatite nanoparticles

Objective

This study investigates the potential of a novel guided tissue regeneration strategy, using fully demineralized dentin infiltrated with silica and hydroxyapatite (HA) nanoparticles (NPs), to remineralize dentin collagen that is completely devoid of native hydroxyapatite.

Methods

Dentin blocks were fully demineralized with 4 N formic acid and subsequently infiltrated with silica and HA NPs. The remineralizing potential of infiltrated dentin was assessed following a twelve week exposure to an artificial saliva solution by means of TEM, EDS and micro-CT. Measurements were taken at baseline and repeated at regular intervals for the duration of the study to quantify the P and Ca levels, the mineral volume percentage and mineral separation of the infiltrated dentin specimens compared to sound dentin and non-infiltrated controls.

Results

Infiltration of demineralized dentin with nano-HA restored up to 55% of the P and Ca levels at baseline. A local increase in the concentration of calcium phosphate compounds over a period of twelve weeks resulted in a higher concentration in P and Ca levels within the infiltrated specimens when compared to the non-infiltrated controls. Remineralization of demineralized dentin with silica NPs by immersion in artificial saliva was the most effective strategy, restoring 20% of the P levels of sound dentin. Micro-CT data showed a 16% recovery of the mineral volume in dentin infiltrated with silica NPs and a significant decrease in the mineral separation to levels comparable to sound dentin.

Significance

Demineralized dentin infiltrated with silica NPs appears to encourage heterogeneous mineralization of the dentin collagen matrix following exposure to an artificial saliva solution.     

Investigation of Dentin Hardness in Roots Exhibiting the Butterfly Effect

Introduction

Most vertical root fractures occur in root canal treated teeth, and they usually run in a buccolingual direction. The butterfly effect is an optical phenomenon seen in some sections of tooth roots. The aim was to investigate the microhardness of dentin in mesiodistal and buccolingual cross sections of roots exhibiting the effect.

Methods

Thirty extracted single-rooted teeth were allocated according to patient age: group 1, 15–24 years; group 2, 25–44 years; and group 3, 45 years and older. Roots were embedded in acrylic and cut into ten 1-mm-thick cross sections. Sections were viewed under a light microscope and coded (1 or 2) according to presence or absence of the butterfly effect. A root scored 20 when all levels featured the butterfly appearance. The 2 teeth with the highest score from each group and 2 control teeth with the minimum score (10) were selected. Two adjacent, consecutive cross sections were chosen from the middle of the roots. Vickers microhardness testing was carried out on the dentin walls.

Results

Mean hardness scores were highest mesiodistally (83.7 kgf/mm²) and lowest buccolingually (56.4 kgf/mm²), a significant difference (P = .028). This trend was found across all age groups.

Conclusions

Root sections with the butterfly effect are harder mesiodistally. This might explain the high prevalence of vertical root fractures that run buccolingually.     

环孢素 A 对大鼠牙槽骨内 DMP1 C 末端和 OPN 表达的影响

目的：观察环孢素A（cyclosporinA,CsA）对大鼠牙槽骨内牙本质基质蛋白1（dentinmatrixprotein,DMP1）C末端和骨桥蛋白（osteopontin,OPN）表达的影响。方法：30只7周龄健康雄性Wistar大鼠,随机等分为对照组和实验组,每组再随机等分为20d、30d和40d3个亚组,实验组大鼠喂饲CsA（30mg／k·d）。免疫组化法染色下颌第一磨牙颊舌向石蜡切片,光镜下观察DMP1C末端和OPN在牙槽骨内的表达情况。结果：与对照组大鼠比较,实验组大鼠牙槽骨内DMP1C末端表达明显下调,OPN表达明显上调;在本实验周期内,上述变化随实验时间的延长而加重。结论：CsA影响大鼠牙槽骨内矿化相关非胶原蛋白DMP1C末端和OPN的表达,推测CsA可能抑制大鼠牙槽骨的矿化。     

三种牙本质脱敏剂治疗（牙合）支托窝牙本质敏感效果分析

目的观察比较诺华敏（NovaMin）、格鲁玛脱敏剂（Gluma）和劲润牙本质保护膜（HybridCoat）3种脱敏剂对验支托窝牙本质敏感治疗的效果。方法选择175颗制备验支托窝的天然牙,随机使用NovaMin、Gluma和HybridCoat进行脱敏,NovaMin组56颗,Gluma组60颗,HybridCoat组59颗,使用视觉模拟评分法记录其敏感度,比较其在连续脱敏5d后即刻、1个月、2个月和3个月的脱敏效果。结果3组患者（牙合）支托窝连续脱敏治疗后,NovaMin组在1个月（P=0．027）、2个月（P=0．023）时的脱敏有效率均高于Gluma组,Gluma组（P=0．040）和HybridCoat组（P=0.012）的即刻脱敏有效率均高于各自3个月时的脱敏有效率,但3个月时组间脱敏有效率差异均无统计意义（P〈0．05）。连续脱敏治疗后,NovaMin组的即刻VAS值高于Gluma组和HybridCoat组（P〈0．05）,而在治疗后1个月和2个月,NovaMin组的VAS值均低于另外2组（P〈0．05）,到3个月时,3组的VAS值差异无统计学意义（P〉0．05）。结论NovaMin脱敏效果持久性好于Gluma和HybridCoat。     

腐蚀性脱敏剂Gluma对牙本质小管封闭效果的离体实验研究

目的：探讨腐蚀性脱敏剂Gluma对牙本质小管的封闭效果。方法：选取正畸治疗减数拔牙的牙齿,构建敏感牙本质模型,随机分为3组,A组（空白对照组）、B组（阻塞性脱敏剂极固宁组）、C组（腐蚀性脱敏剂Gluma组）;测量各组的牙本质渗透率及冷热、牙刷磨耗处理后渗透率变化情况,并扫描电镜观察牙本质小管的横截面及纵切面形态。结果：脱敏剂处理后的牙本质渗透率为C组〈B组〈A组,差异具有统计学意义（P〈0.05）。经冷热、牙刷磨耗处理后,A和B组牙本质渗透率较前显著增加,差异具有统计学差异（P〈0.05）,而C组牙本质渗透率与处理前差异无统计学意义。与其余两组相比较,C组扫描电镜可观察到牙本质表面沉积物绝大部分堵塞牙本质小管,且小管内有颗粒状沉积物。结论：离体实验研究发现脱敏剂Gluma和极固宁均可降低敏感牙本质的渗透性、封闭开放的牙本质小管,而Gluma的封闭作用较极固宁持久,治疗牙本质敏感症可优先考虑脱敏剂Gluma。