碧兰糊剂和碘仿糊剂根管充填后疼痛的比较

目的比较碧兰糊剂和碘仿糊剂根管充填后疼痛的发生率与持续时间。方法将根管预备后行根管充填的260颗患牙随机分成2组,碧兰糊剂组130颗患牙,用碧兰糊剂加牙胶尖充填,碘仿糊剂组130颗患牙,用碘仿糊剂加牙胶尖充填,观察术后疼痛的发生率及持续时间。结果碧兰糊剂组的根充后疼痛发生率为10.8%(14/130),碘仿糊剂组为32.3%(42/130),两组间差异具有统计学意义(χ2=4.90,P<0.05)。碧兰糊剂组根充后疼痛持续1～2 d 10颗,3～4 d 3颗,5～6 d 1颗;而碘仿糊剂组根充后疼痛持续1～2 d 6颗,3～4 d 20颗,5～6 d 14颗,7 d以上2颗。两组疼痛持续时间差异具有统计学意义(χ2=73.11,P<0.01)。结论碧兰糊剂根充后疼痛的发生率明显低于碘仿糊剂,且疼痛持续的时间较短。     

六手操作在根管预备中的应用

目的 探讨六手操作在根管预备中的应用效果.方法 收集拟接受根管预备的患者106例,治疗完成后,记录每颗患牙的诊治时间,并由患者填写综合满意度调查表.比较采用六手操作和四手操作进行根管预备所需诊治时间及患者治疗后的综合满意度.结果 采用六手操作和四手操作进行根管预备,每颗患牙平均诊治时间分别为(44.96±12.59) min、(55.33±14.53) min,差异有统计学意义(t=3.94,P=0.0003).患者治疗后的综合满意度分别为(8.89±0.69)分和(8.31±1.16)分,差异亦有统计学意义(t=3.09,P=0.0016).结论 在根管预备中采用六手操作能显著提高医护人员的工作效率和患者的综合满意度.     

显微超声技术在根中下1/3取断针的疗效及策略

目的：分析在根管显微镜下应用超声技术取出根管中下1/3断针的临床效果,提出预防措施。方法：收集5年来门诊根管预备断针发生在根中下1/3的患者36例,均在显微镜下用超声根管工作尖取断针。结果：36例根管内断针取出29例,失败7例,成功率为80.5%,4例建立旁路,1例拔除,2例留内观察。结论：根管显微镜下应用超声技术取出根管内断针相对安全有效。     

初学者应用两种镍钛机动器械预备树脂弯曲根管的效果比较

目的 比较初学者应用两种机用镍钛器械Protaper和Her0642预备树脂弯曲根管的效果.方法 选取仿制单弯树脂根管32个,15名初学者分别用两种机用镍钛系统Protaper和Her0642进行根管预备,2个仿制单弯树脂根管为阴性对照.分别从推出根尖碎屑量、根尖偏移量及根管弯曲度变化等方面评价两种器械系统的根管预备效果.所有数据均采用SPSS 13.0软件包进行统计学分析.结果 Protaper组预备前后根管弯曲度平均减小6.77°,Hero642组减小5.480°,Protaper组减小根管弯曲度较Hero642组明显.Protaper组成形后的根管宽度均值均大于Hero642组,且根管口、根中1/3成形后的根管宽度差异有统计学意义(P<0.05).此外,根管预备过程中Protaper器械折断3支,Hero642器械折断1支.结论 对于初次使用机用镍钛器械的操作者,尽管Protaper具有良好根管成形的优点,但Hero642系统操作技术简单容易掌握、高效、安全,更适合初学者在临床上使用.     

Sealability of MTA and calcium hydroxidecontaining sealers

Objectives

The aim of this study was to evaluate the apical sealability of Fillapex^®, Endo-CPM-Sealer^® and Sealapex^®.

Material and Methods

Ninety-four freshly extracted single-rooted teeth were selected and decoronated. All teeth were radiographed to confirm the existence of a single and straight root canal, which was prepared using Protaper Universal and 2.5% sodium hypochlorite. The teeth were randomly divided in groups of 10 specimens each according to the sealer, and the canals were filled using the single cone technique and one of the sealers. Four additional teeth were used as controls. The teeth were submitted to dye leakage with Rhodamine B for 24 h but using vacuum on the initial 15 min. Thereafter, they were cut longitudinally and the leakage was measured in a linear fashion from apex to crown. Data were analyzed by ANOVA and Tukey''s tests at 5% significance level.

Results

Fillapex^® and Sealapex^® showed significantly less dye leakage than Endo-CPM-Sealer^® (p<0.05).

Conclusions

It was concluded that Fillapex^® and Sealapex^® were able to prevent apical dye leakage differently from Endo-CPM-Sealer^®.     

Push-out bond strength and SEM evaluation of a new bonding approach into the root canal

Objective

This study evaluated the performance of different adhesive systems in fiber post placement aiming to clarify the influence of different hydrophobic experimental blend adhesives, and of one commercially available adhesive on the frictional retention during a luting procedure.

Material and Methods

One luting agent (70 Wt% BisGMA, 28.5% TEGDMA; 1.5% p-tolyldiethanolamine) to cement fiber posts into root canals was applied with 4 different adhesive combinations: Group 1: The etched roots were rinsed with water for 30 s to remove the phosphoric acid, then rinsed with 99.6% ethanol for 30 s, and blotdried. A trial adhesive (base to catalyst on a 1:1 ratio) was used with an experimental luting agent (35% Bis-GMA, 14.37% TeGDMA, 0.5% eDMAB, 0.13% CQ); Group 2: A trial adhesive (base to catalyst on a 1:2 ratio) was luted as in Group 1; Group 3: One-Step Plus (OSP, Bisco Inc.) following the ethanol bonding technique in combination with the luting agent as in Group 1; Group 4: OSP strictly following the manufacturer''s instructions using the luting agent as in Group 1. The groups were challenged with push-out tests. Posted root slices were loaded until post segment extrusion in the apical-coronal direction. Failure modes were analyzed under scanning electron microscopy.

Results

Push-out strength was not significantly influenced by the luting agent (p>0.05). No statistically significant differences among the tested groups were found as Group 1 (exp 1 - ethanol-wet bonding technique)=Group 2 (exp 2 - ethanol-wet bonding technique)=Group 3 (OSP - ethanol-wet bonding technique)=Group 4 (control, OSP - water-wet bonding technique) (p>0.05). The dominating failure modes in all the groups were cohesive/adhesive failures, which were predominantly observed on the post/luting agent interface.

Conclusions

The results of this study support the hypothesis that the proposal to replace water with ethanol to bond fiber posts to the root canal using highly hydrophobic resin is plausible, but this seems to be more the proof of a concept than a clinically applicable procedure.     

基质金属蛋白酶-9基因与牙周病的相关性研究进展

MMP-9即基质金属蛋白酶-9,在人体多种组织均有表达。编码该蛋白酶的基因称MMP-9基因,该基因不仅在决定个体对某些疾病的易感性上起重要作用,而且其表达与某些疾病的发生、发展密切相关。牙周病为发生在牙周支持组织（牙龈、牙周膜、牙槽骨、牙骨质）的疾病。近年研究发现MMP-9基因表达及单核苷酸多态性（SNP）在牙周病发病机制中起到重要作用。     

Influence of cementum on the demineralization and remineralization processes of root surface caries in vitro

The influence of the nature of the root surface on the demineralization and remineralization processes within artificial fluoride-treated caries lesions was investigated using microscopic and X-ray microanalytical methods. Traces of fluoride were detected in the outer parts (about 25 µm) of the lesions after the application of fluorides, and a high mineral content was proved for the same region by means of microanalytical calcium estimation. The location of this mineral-rich band in relation to the root surface was deeper into the root depending on the existence and thickness of a cementum layer. However, within the dentine the location and intensity of the mineral content were unaffected by the cementum. Investigation of artificial caries lesions without fluoride treatment showed the following: The degree of mineralization was kept at a higher level near the root surface in the presence of cementum. Consequently, a cementum layer gives some initial caries resistance of the root surface.     

Correlates of root caries experience in middle-aged and older adults in the Northwest Practice-based REsearch Collaborative in Evidence-based DENTistry research network

BackgroundThe authors examined the correlates of root caries experience for middle-aged adults (aged 45–64 years) and older adults (65 years and older) to test the hypothesis that the factors related to root caries are different for middle-aged adults than they are for older adults.MethodsThe authors conducted an observational cross-sectional study that focused on adult patients aged 45 to 97 years recruited from the Northwest Practice-based REsearch Collaborative in Evidence-based DENTistry research network (N = 775). The outcome variable was any root caries experience (no/yes). The authors hypothesized that sociodemographic, intra- oral and behavioral factors were root caries correlates. The authors used Poisson regression models to generate overall and age-stratified prevalence ratios (PRs) of root caries, and they used generalized estimating equations to account for practice-level clustering of participants.ResultsA total of 19.6 percent of adults had any root caries. A dentist’s assessment that the patient was at high risk of developing any caries was associated with greater prevalence of root caries experience in both middle-aged adults (PR, 2.70; 95 percent confidence interval [CI], 1.63–4.46) and older adults (PR, 1.87; 95 percent CI, 1.19–2.95). The following factors were associated significantly with increased root caries prevalence but only for middle-aged adults: male sex (P = .02), self-reported dry mouth (P < .001), exposed roots (P = .03) and increased frequency of eating or drinking between meals (P = .03). No other covariates were related to root caries experience for older adults.ConclusionsWithin a practice-based research network, the factors associated with root caries experience were different for middle-aged adults than they were for older adults. Research is needed to identify relevant root caries correlates for adults 65 years and older.Practical ImplicationsInterventions aimed at preventing root caries are likely to be different for middle-aged adults than for older adults. Dentists should use root caries prevention programs that address appropriate aged-based risk factors.     

Immunolocalization of Smad-4 in developing molar roots of alendronate-treated rats

Introduction

During root formation, Smad-4 plays a key role during the epithelial–mesenchymal interactions and the Hertwig's epithelial root sheath (HERS) apical proliferation. The root formation and eruption of rat molars is impeded by alendronate treatment due to the inhibition of bone resortion by this drug. The present study aimed to examine the structures affected in the developing root and immunodetect the presence of Smad-4 in rats treated with alendronate.

Methods

Newborn Wistar rats were daily injected 2.5 mg/kg alendronate (ALN) during 9, 12 and 30 days. The controls (CON) were injected with saline. The maxillae were fixed and embedded in paraffin or Spurr resin. Paraffin sections were incubated in Smad-4 antibody that was labelled with DAB. The ultrathin sections were examined in a transmission electron microscope.

Results

In ALN, a short portion of root dentine was formed; the epithelial diaphragm (ED) and the dental follicle (DF) were disorganized by the contact of bone trabeculae. The (CON) molar roots developed normally. Smad-4 labelling was detected in the cytoplasm of fibroblasts and cementoblasts adjacent to the cementum in CON; in ALN group, few ED cells presented weak immunolabelling. Ultrastructurally, the ED and DF appeared disrupted due to the presence of thin bone trabeculae between its cells. It resulted in the lack of apical proliferation of HERS and, consequently, arrest of root formation.

Conclusion

The immunodetection of Smad-4 in the DF cells of ALN specimens indicates that the signalling for the differentiation of these cells into cementum-forming fibroblasts and cementoblasts occurs, despite the impairment of root elongation.