Physicochemical evaluation of silica-glass fiber reinforced polymers for prosthodontic applications

This investigation was designed to formulate silica-glass fiber reinforced polymeric materials. Fused silica-glass fibers were chosen for the study. They were heat-treated at various temperatures (500 degrees C, 800 degrees C and 1100 degrees C), silanized, sized and incorporated in two modified resin mixtures (A and B). The flexural properties in dry and wet conditions were tested and statistically analyzed, and the content of residual methyl methacrylate (MMA) monomer, dimensional changes with temperature, water sorption and solubility were determined. Woven fibers [36.9% (wt/wt)], heat-treated at 500 degrees C, gave the highest strength values for the polymeric composites (an ultimate transverse strength of 200 Mpa and a flexural modulus of 10 GPa) compared with the fibers heat-treated at other temperatures. There was no statistically significant difference in the measured flexural properties between resins A and B regarding fiber treatment and water storage time. These fiber composites had a small quantity of residual MMA content [0.37 +/- 0.007% (wt/wt)] and very low water solubility, indicating good biocompatibility. It was suggested that silica-glass fibers could be used for reinforcement as a result of their anticipated good qualities in aqueous environments, such as the oral environment.     

ERA全口覆盖义齿修复保留残根的半口牙列缺失患者的临床评估

目的：研究ERA附着体全口覆盖义齿的临床修复效果。方法：35例保留残根的半口牙列缺失患者，采用ERA全口覆盖义齿修复。结果：经过6个月至1年3个月时间随访，患者表示对该义齿的固位性能、咀嚼效能、舒适程度，以及装卸的方便程度感到满意。有1例出现ERA阳性部件老化，进行了即刻更换，其余无失败病例。结论：采用ERA全口覆盖义齿修复保留残根的半口牙列缺失病例，临床观察患者较满意，提示该方法是一种方便、可靠的修复方式。但ERA附着体的阳性部件需要根据老化情况，随时进行更换。     

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目的评价牙冠延长术在牙体缺损达龈下的残根残冠修复中的临床疗效。方法对大连大学附属中山医院口腔科2004年12月至2007年11月收治的48例患者52颗牙体缺损达龈下的患牙,术前按断端位于龈下最深距离分为浅缺损组(28颗患牙,距离<2.5mm)和深缺损组(24颗患牙,2.5mm≤距离≤4.0mm),均采用牙冠延长术暴露龈下牙体断面,术后6周行桩冠修复。分别记录手术前后牙周探诊深度(PD)、菌斑指数(PLI),龈沟出血指数(SBI)和牙齿松动度,观察临床疗效。结果两组病例术后6周牙体断端均暴露较好、龈缘颜色正常。术后6个月修复满意率为80.77%。浅缺损组术后无松动,修复效果满意。深缺损组术后半数出现I度松动,修复效果欠佳,两组修复效果比较差异有统计学意义(P<0.05)。术后各阶段两组的PD、PLI、SBI均明显优于术前(P>0.05)。结论牙冠延长术有利于残根残冠的保存和修复,但要注意适应证的选择。     

填料含量对牙科光固化粘结剂残余单体量的影响

目的：探讨填料的加入对牙科光固化粘结剂聚合转化度的影响。方法：采用高效液相色谱仪测试了不同填料含量的光固化粘结剂固化后的残余单体量。结果：无填料粘接剂残余单体量最大，随填料含量增加而减少；照射６０ｓ，９．１％组显示最小。结论：填料含量５％（ｗｔ），照射６０ｓ较适宜     

The effects of fixed and removable implant-stabilised prostheses on posterior mandibular residual ridge resorption

Abstract: This study investigated the change over time in the area of the posterior mandibular residual ridge in patients wearing either i) mandibular overdentures stabilised by two implants (Brånemark System; Nobel Biocare, Göteborg, Sweden) connected by a bar, or ii) mandibular fixed cantilever prostheses stabilised on five or six implants. Proportional measurements were made in order to compare the area of the residual ridge with an area of bone uninfluenced by resorption. Measurements were made by digitising tracings of panoramic radiographs that were taken shortly after implant insertion and up to seven years later. With the use of overdentures, the posterior bone area index reduced by a mean of 1.1% per annum, while a mean bone area index increase of 1.6% per annum was demonstrated in association with fixed prostheses. A multiple linear regression model was fitted to predict the change in posterior area from type of prosthesis, gender, age, years of edentulism and initial height of the mandible. The model was only significant for initial height of mandible (P = 0.04) and type of prosthesis (P = 0.0001). In conclusion, patients rehabilitated with implant‐stabilised mandibular overdentures demonstrated low rates of posterior mandibular residual ridge resorption, while patients rehabilitated with implant‐stabilised mandibular fixed cantilever prostheses demonstrated bone apposition in the same area.     

Formation and resolution of ankylosis under application of recombinant human bone morphogenetic protein-2 (rhBMP-2) to class III furcation defects in cats

OBJECTIVES: Periodontal regeneration under application of bone morphogenetic protein (BMP) is compromised by ankylosis. Ankylosis disappearance following application of BMP has been observed in the case of a small defect, which might be beneficial change for periodontal regeneration. However, the histological observation of ankylosis disappearance has not been demonstrated in a large defect. The purpose of this present study was to confirm resolution of ankylosis during periodontal regeneration by recombinant human BMP-2 (rhBMP-2) applied to class III furcation defects. MATERIAL AND METHODS: Class III furcation defects were created in the premolars of six adult cats. The rhBMP-2 material, prepared by applying rhBMP-2 to a combination of polylactic acid-polygricolic copolymer and gelatin sponge (PGS; 0.33 microg rhBMP-2/mm(3) PGS) or control material containing only PGS, was implanted into each defect. The cats were killed at 3, 6 or 12 weeks after surgery and serial sections were prepared for histological and histometrical observation. RESULTS: Ankylosis was observed in some of the rhBMP-2/PGS group at 3 and 6 weeks, but not at 12 weeks. At 6 weeks, osteoclast-like cells were visible in the rhBMP-2/PGS group with ankylosis. Residual PGS was evident between the bone and root surface in the rhBMP-2/PGS group without ankylosis at 3 weeks. CONCLUSIONS: Resolution of ankylosis by osteoclast-like cells possibly occurred under application of rhBMP-2. Residual PGS might play an important role in preventing ankylosis formation.     

预成根管钉或铸造桩核修复老年人残根残冠的临床分析

目的：比较预成根管钉和铸造桩核在老年人前后牙修复时的操作时间及成功率。方法：随机选择需做桩核或根管钉修复的老年病人，记录操作时间，随访观察成功率。结果：后牙的桩核修复操作时间均长于预成根管钉（P〈0．001）；前牙桩核与根管钉操作时间2组差异无显著性（P〉0．05）；前牙桩核修复成功率高于预成根管钉（P〈0.05）；后牙桩核修复和预成根管钉修复2组差异无显著性（P〉0.05）。结论：在老年患者前牙首选桩核，后牙首选根管钉。     

The influence of periodontal status and serum biomarkers on salivary leptin levels in systemic lupus erythematosus patients

ObjectiveThis study aimed to investigate the influence of periodontal status, clinical data, and serum markers on salivary leptin levels in patients with systemic lupus erythematosus (SLE).MethodsA case–control study was conducted with 38 patients with SLE and 29 healthy controls. Periodontal data included periodontal probing depth (PPD), clinical attachment level (CAL), and gingival bleeding on probing (BOP). Stimulated saliva samples were collected to analyze salivary leptin levels. Clinical and serum data were collected from the SLE group. Statistical analysis included the t-test, Mann–Whitney test, Spearman correlation coefficient, and a structural equation model.ResultsThe SLE group had a lower salivary leptin level than the control group (P = 0.002). The model revealed that SLE had an inverse and independent effect on salivary leptin (standardized estimate =  ? 0.289, P = 0.023). Moreover, salivary leptin level negatively correlated with the serum levels of triglyceride, creatinine, and leukocytes, positively correlated with the serum total cholesterol, but was not significantly correlated with the periodontal status.ConclusionThese findings suggest that patients with SLE have a lower salivary leptin level. In addition, the level of salivary leptin does not appear to be related to periodontal status in patients with SLE.     

Influence of thickness and cooling rate on development of spontaneous cracks in porcelain/zirconia structures

Background: Clinical studies reporting the outcome of zirconia‐based restorations indicate that the strength of the zirconia frameworks is sufficient to withstand masticatory forces. However, a significant incidence of cohesive fracture of the veneering porcelain has been reported. The aim of this study was to investigate spontaneous crack development (chipping, rupture) in a range of porcelains veneered to a zirconia core as a result of thermal stresses induced by changes in thickness and cooling rate. The hypothesis tested was that crack incidence would increase with increased veneer thickness and faster cooling rates. Methods: Zirconia spheres (diameter 7.8 mm) were veneered with 1.5 gm (thickness ratio 1:2) and 2.5 gm (thickness ratio 1:1) of five nominally compatible commercially available porcelains. The manufacturers’ firing cycles and a rapid cooling firing cycle were followed. Results: Multiple regression analysis showed positive associations between the occurrence of cracks and the three covariates (materials, thickness and cooling rate). The incidence of cracks and rupture of the veneering porcelain increased with a faster cooling rate and increased thickness of the specimens in three porcelain–zirconia combinations. Conclusions: Crack incidence increased with increased porcelain veneer thickness and faster cooling rates in nominally compatible porcelain/zirconia systems in the geometrically configured specimens tested.     

Semont管石解脱法联合前列地尔治疗良性位置性眩晕的疗效及发生残余症状的影响因素分析

目的 探讨Semont管石解脱法联合前列地尔在良性位置性眩晕患者中的应用及发生残余症状的影响因素。方法 选取2018年1月—2019年12月在天津医院进行治疗的良性位置性眩晕患者120例为研究对象,随机分为观察组和对照组,每组60例。两组患者均采取Semont管石解脱法治疗。观察组患者在此基础上联合前列地尔治疗。比较两组患者的疗效、生活质量、复诊情况;多因素Logistic回归模型分析患者术后发生残余症状的影响因素。结果 与对照组相比,观察组患者的治疗总有效率升高（P <0.05）;经过治疗后,两组患者的DHI量表各项指标均下降,且观察组患者的功能、情感、躯体、总分差值高于对照组（P <0.05）;观察组的无残余症状患者数多于对照组,有残余症状、复发患者数少于对照组（P <0.05）;有残余症状与无残余症状患者的发病月份、睡眠障碍、DHI量表评分、高血压、糖尿病、冠心病比较,差异有统计学意义（P <0.05）;发病月份为12～2月［O^R=1.63（95% CI：1.33,2.32）］、睡眠障碍［O^R=1.06（95% CI：0.75,2.11）］、DHI量表评分［O^R=2.12（95% CI：1.36,2.62）］、高血压［O^R=1.12（95% CI：1.02,1.20）］、糖尿病［O^R=0.71（95% CI：0.52,0.94）］、冠心病［O^R=2.01（95% CI：1.56,2.30）］为患者治疗后发生残余症状的独立危险因素（P <0.05）。结论 Semont管石解脱法结合前列地尔对良性位置性眩晕患者的治疗效果显著,复发率较低;发病月份为12～2月、睡眠障碍、DHI评分较高、高血压、糖尿病、冠心病为患者治疗后发生残余症状的独立危险因素。