Effect of pretreatments on the metal–ceramic bonding strength of a Pd–Ag alloy

Objectives

The purpose of this study was to evaluate the efficacy of surface treatments on the bonding properties between a metal and ceramic.

Methods

Sixty metal specimens were divided equally into four groups of 15 samples each. These groups received different treatments (Gr1: 250 μm Al₂O₃ + preoxidation; Gr2: 250 μm Al₂O₃ + degassing; Gr3: 120 μm Al₂O₃ + preoxidation; Gr4: 120 μm Al₂O₃ + degassing). Bond strengths were evaluated using a three-point bending test. The results were analyzed using 2-way ANOVA and Tukey's test. Scanning electron microscopy and energy dispersive spectroscopy were used to observe the microscopic features, elemental compositions and distributions, and diffusion in the specimens. Mechanical profiler was used to measure the roughness of metal surface.

Results

The bond strengths of the four groups ranged from 45.00 ± 3.63 MPa to 51.61 ± 5.91 MPa, with significant differences (P < .05). The specimen that received the pretreatment of 250 μm Al₂O₃ air-particle abrasion + degassing had the highest bond strength. Heating under different oxygen partial pressures caused the final Pd–Ag alloys to have varying degrees of internal oxidation and different quantities of metallic nodules. None of the elements in either the ceramic or the Pd–Ag alloy layer diffused into the other layer.

Conclusions

The metal–ceramic specimen subjected to air-particle abrasion with 250 μm Al₂O₃ and degassed before porcelain firing had significantly higher bond strength than specimens treated differently.     

气体雾化制备齿用Ag—稀土球形汞合金粉末

本文讨论了用气体雾化技术制备Ａｇ－稀土球汞合金粉末的工艺过程。用气体雾化方法制备的Ａｇ－稀土球形汞合金粉末，组织结构均匀，粒度分布、浸润性及充填效果均能满足齿科用充填材料的要求。     

稀土Ce/Ag/ZnO对白色念珠菌的氧化应激抗菌机制研究

目的 研究稀土纳米复合材料Ce/Ag/ZnO对口腔白念珠菌的氧化应激抗菌机制。方法 通过细菌平板培养、绘制细胞生长曲线、扫描电子显微镜（SEM）观察以及氧化应激相关生化指标检测等实验方法，探究该材料对白念珠菌的抗菌机制。结果 稀土纳米复合材料Ce/Ag/ZnO作用于白念珠菌时，其MIC、MBC分别为0.156 mg/mL、0.313 mg/mL；SEM观察发现细菌皱缩塌陷、内容物泄漏，细胞膜严重破坏；细菌的活性氧（ROS）水平、脂质过氧化（LPO）程度以及过氧化氢酶（CAT）活力值均有明显升高（P＜0.05）。结论 稀土改性的纳米材料具有良好的抗菌效果，揭示其通过诱导白念珠菌内部产生氧化应激反应的抗菌机制，为未来该材料应用于义齿基托制作，预防口腔义齿性口炎发生提供理论支持。     

In vivo study of the effectiveness of quantitative percussion diagnostics as an indicator of the level of structural pathology of teeth after restoration

Statement of problem

Conventional diagnostic aids based upon imagery and patient symptoms do not indicate whether restorative treatments have eliminated structural pathology.

变形链球菌AgⅠ/Ⅱ蛋白编码可变区(Ⅴ+)基因表达质粒的构建

目的 构建变形链球菌（S.mutans血清型f,s.mutnas血清型c)表面蛋白编码Ⅴ 基因重组质粒pCVc,pCVf和重组表达质粒pSRVc,pSRVf。方法 用PCR方法从sr基因中扩增目的基因片段与质粒pCR2.1连接，再将V 区基因片段转移到高效表达质粒pET21a( )。酶切电泳检测，结果 PCR扩增产物为1.16kb的DNA带，测序结果与sr基因序列V 区一致。酶切电泳证实V 区基因片段整合到pET21a( )的适当部位，构建重组表达质粒pSRVc,pSRVf。结论 本试验成功地构建了携带V 基因片段的表达质粒pSRVc,pSRVf。     

Influence of the site of origin on the outcome of squamous cell carcinoma of the maxilla—oral versus sinus

The maxilla may be affected by squamous cell carcinoma (SCC) from both oral and sinus sites. We sought to determine whether the site of origin of the maxillary tumour, oral as compared to sinus, influences survival. Univariate Kaplan–Meier and multivariate Cox proportional hazard models analysis of 58 patients with SCC involving the maxilla, treated with curative intent, was conducted. The overall 5-year disease-free survival for the group was 41.7%. Five-year disease-free survival for oral subsite SCC was 56.8%, while for sinus subsite was only 21.6%. Univariate analysis found SCC of sinus origin to be associated with a poorer prognosis, however this was not confirmed on multivariate analysis. T-stage and positive margins were found to be the only independent risk factors. For SCC of the maxilla, sinus origin of the tumour per se does not confer a poorer prognosis; however, as a result of the complex anatomy of the midface, these tumours can present at an advanced stage, while surgical control of the disease can be more difficult, especially posteriorly. Tumour size and positive margins were the determinants of a poor prognosis in this group of patients with maxillary SCC.     

纳米Ag—SiO2颗粒对小鼠成纤维细胞（L-929）的毒性研究

目的：探讨纳米Ag—SiO2颗粒对小鼠成纤维细胞（L-929）的体外毒性作用。方法：使用透射电镜（TEM）对纳米颗粒进行表征;CCK一8法观察在24h、48h、72h不同浓度纳米颗粒对L-929细胞活性的影响;倒置显微镜观察染毒24h后细胞形态的改变,并检测细胞上清液中乳酸脱氢酶（LDH）漏出率。结果：L-929细胞的生长活性随着纳米Ag—SiO2颗粒浓度的升高和染毒时间的延长而下降,低浓度组（6．25,12．5μg／mL）与对照组无明显差异,倒置显微镜下细胞形态正常,生长良好。而高浓度组（50,100μg／mL）与对照组有明显差异,透射电镜下观察细胞有明显的空泡变性,培养液上清中LDH活性明显升高。结论：纳米Ag—SiO2颗粒的体外细胞毒性呈剂量一时间依赖关系,低浓度组具有良好的生物相容性,高浓度组具有一定的细胞毒性,其毒性可能与细胞膜的完整性遭到破坏有关．     

In vivo effects of geranylgeraniol on the development of bisphosphonate-related osteonecrosis of the jaws

Background

Bisphosphonate-related osteonecrosis of the jaws (BRONJ) is a complication of the bisphosphonate (BP) treatment and its pathopysiology is still not fully understood. The existing preventive and treatment options require updates and more attention. Geranylgeraniol (GGOH) so far demonstrated an increased activity and viability of the cells previously treated with zoledronic acid (ZA). The aim of this study was to evaluate the in vivo effects of GGOH on the development of BRONJ.

FTIR characterization of the setting reaction of biodentine™

Objective

To provide insight of the setting reactions of Biodentine?, a hydraulic calcium silicate cement, based upon observations using Fourier Transform Infra-Red (FTIR) spectroscopy.

Consideration of effect of the amount of mandibular setback on the submental region in the planning of orthodontic–orthognathic treatment

Aesthetic outcome has gained in importance in the treatment of patients with orthognathic problems. Historically, Class III malocclusions have historically been treated by isolated mandibular setback and maxillary advancement, whereas bimaxillary procedures have recently become the more common option. Functional outcome and stability have been discussed previously. The aim of this observational study was to evaluate the effect of mandibular setback (BSSO) on the cervical region. We studied 38 Class III patients (20 women and 18 men, mean (SD) age 25 (0.8) years) who we identified from our clinical records and who were treated between 1 January 2002 and 30 December2012 with mandibular setback procedures and followed up for 6 months. To study the effect of the amount of mandibular setback on the aesthetic outcome we have distinguished between patients with less than 5 mm setback and those with 5 mm or more. In patients whose mandibular setback was less than 5 mm there was no significant change in cervical length. However, it decreased significantly in patients in whom the movement was 5 mm or more. Postoperatively the lip–chin–throat angle (p = 0.02), the length of the lower lip (p = 0.002), and the length of the upper lip (p = 0.003) from the aesthetic line also differed significantly between the 2 groups. Our observations strongly suggest that all these relations should be considered when treatment is being planned to avoid an unpleasant aesthetic impact on the chin region.     

Electrosynthesis of novel π-extended benzofuran derivatives of porphyrincatecholes

Two new functionalized π-extended benzofuran catechol porphyrins and nanostructured Mn-porphyrins have been synthesized by a green one-pot method and structurally characterized by spectroscopic analysis. The electro-oxidation of 5,10,15,20-tetrakis(2,3-dihydroxyphenyl) porphyrins(1a-b) with four catechol units in the presence of 3-hydroxy-1H-phenalene-1-one (3) as bidentate nucleophile has been done and benzofuran rings have formed by the intermolecular and intramolecular Michel addition reactions. Coulometry and voltammetry results allowed us to propose four independent ECEC mechanisms for the electrochemical oxidation pathway. Functionalization of the porphyrins affected their photophysical properties such as the efficiency of the fluorescence that would support the energy transfer between the porphyrin core and the substituted subunits.     

Biopsy examination of squamous cell carcinoma of the tongue: Source of significant prognostic information?

Histological analysis of tumour resection for squamous cell carcinoma (SCC) of the tongue yields prognostic information. We analysed histological slides of biopsy and tumour resection specimens using an adapted malignancy grading score and analysed variables of neck dissections. There was moderate correlation between biopsy and tumour resection using malignancy grading scores (correlation coefficient 0.45); good agreement of tumour grade (79%), tumour depth (76%), and type of invasive front (80%), but correlation was only fair to moderate (κ = 0.38, κ = 0.51, and κ = 0.41, respectively). Correlation of the biopsy grading score and invaded nodes in the neck, extra capsular spread, and soft tissue disease was not significant.     

A study on the fit of the base plate —Influence of canditions of storage—

The aims of this study was to define the effect of storage conditions of base plates, which consist of self-curing resin. Examinantions were made on the dimensional accuracy with the passage of time of base plate stored in water and air on a plaster model for standerdized maxillary edentulous. The following conclusions were obtained;

Does the size matter? Evaluation of effect of incorporation of silver nanoparticles of varying particle size on the antimicrobial activity and properties of irreversible hydrocolloid impression material

Objectives

The main objective of the present in vitro study is to evaluate the antimicrobial activity and properties of irreversible hydrocolloid impression material incorporated with silver nanoparticles of varying size at different concentrations.

Value of videoroscopy in the detection of alterations of? Actinic Cheilitis?and the selection of biopsy areas

Background

To demonstrate the value of videoroscopy in identifying lesions and alterations not seen by oroscopy and to select the area for biopsy.

Material and Methods

Eighty patients were subjected to anamnesis, physical exam, videoroscopy exam, toluidine blue test and biopsy. A diagram of the lips was created to record the exact location where the lesion was found.

Results

Physical exam identified 287 lesions, and videoroscopy identified 587 lesions; erythema and white lesions were the most common lesions associated with actinic cheilitis. Of the 59 performed biopsies, 32 (52.4%) cases were identified by videoroscopy that showed lesions that were not detected during physical examination.

Conclusions

The establishment of a diagram of the lip permitted registration of the precise location of the lesion. Videoroscopy was effective in locating lesions not seen by oroscopy. Both videoroscopy and the diagram of the lips allowed for better and earlier diagnosis and better patient follow-up for those with actinic cheilitis. Key words: Actinic cheilitis, potentially malignant disorder, videoroscopy, dermatoscopy, lip. oroscopy, diagram of lip.     

Juvenile cemento-ossifying fibroma of the maxilla:Report of one case and renew of the literature

Juvenile cemento-ossifying fibroma (JCOF) is a rare lesion that exhibits a slow growing but may reach massive proportion and cause considerable cosmetic and functional problems. This lesion has the tendency for recurrence following incomplete excision. A case report of giant JCOF in a 46-year-old female with 23-year history is presented. Local excision and thorough curettage was performed and the normal skeletal structure was maximally preserved. 15-month follow up demonstrated no sign of recurrence.