A comparative study of gold UCLA-type and CAD/CAM titanium implant abutments

PURPOSE

The aim of this study was to evaluate the interface accuracy of computer-assisted designed and manufactured (CAD/CAM) titanium abutments and implant fixture compared to gold-cast UCLA abutments.

MATERIALS AND METHODS

An external connection implant system (Mark III, n=10) and an internal connection implant system (Replace Select, n=10) were used, 5 of each group were connected to milled titanium abutment and the rest were connected to the gold-cast UCLA abutments. The implant fixture and abutment were tightened to torque of 35 Ncm using a digital torque gauge, and initial detorque values were measured 10 minutes after tightening. To mimic the mastication, a cyclic loading was applied at 14 Hz for one million cycles, with the stress amplitude range being within 0 N to 100 N. After the cyclic loading, detorque values were measured again. The fixture-abutment gaps were measured under a microscope and recorded with an accuracy of ±0.1 µm at 50 points.

RESULTS

Initial detorque values of milled abutment were significantly higher than those of cast abutment (P<.05). Detorque values after one million dynamic cyclic loadings were not significantly different (P>.05). After cyclic loading, detorque values of cast abutment increased, but those of milled abutment decreased (P<.05). There was no significant difference of gap dimension between the milled abutment group and the cast abutment group after cyclic loading.

CONCLUSION

In conclusion, CAD/CAM milled titanium abutment can be fabricated with sufficient accuracy to permit screw joint stability between abutment and fixture comparable to that of the traditional gold cast UCLA abutment.     

Anion gap‐opening metabolic acidosis and urinary findings in the early diagnosis of ethylene glycol poisoning: A case report

Causative agent identification is important in the treatment of poisoning. We report the case of a patient who presented with an altered level of consciousness after drinking a fluorescent pink liquid. Upon measuring the anion gap and urinary calcium oxalate level, the patient was diagnosed with early ethylene glycol poisoning.     

耳内镜与显微镜下鼓室成形术手术效果的比较分析

目的 比较耳内镜与传统显微镜下鼓室成形术的安全性和疗效.方法 回顾性分析2018年12月-2019年12月在清远市人民医院耳鼻喉科接受鼓室成形术患者的病历资料.根据手术方式将患者分为经耳内镜鼓室成形术组(耳内镜组)和经显微镜鼓室成形术组(显微镜组).比较两组患者手术引起感音神经性耳聋的风险(骨导听阈上升)、手术对听觉的...     

山东省卫生健康行业网络安全调查与分析

目的/意义调查分析山东省卫生健康行业网络安全现状,精确定位行业网络安全短板,提升风险管理决策能力。方法/过程以问卷方式采集数据,从医疗机构等级和地域分布两个维度进行网络安全差距分析。结果/结论针对当前山东省基层医疗卫生机构信息化建设管理和技术防护层面的问题,提出卫生健康行业网络安全治理具体措施。     

Endothelium‐dependent hyperpolarizations: Past beliefs and present facts

Endothelium‐dependent relaxations are attributed to the release of various factors, such as nitric oxide, carbon monoxide, reactive oxygen species, adenosine, peptides and arachidonic acid metabolites derived from the cyclooxygenases, lipoxygenases, and cytochrome P450 monooxygenases pathways. The hyperpolarization of the smooth muscle cell can contribute to or be an integral part of the mechanisms underlying the relaxations elicited by virtually all these endothelial mediators. These endothelium‐derived factors can activate different families of K⁺ channels of the vascular smooth muscle. Other events associated with the hyperpolarization of both the endothelial and the vascular smooth muscle cells (endothelium‐derived hyperpolarizing factor (EDHF)‐mediated responses) contribute also to endothelium‐dependent relaxations. These responses involve an increase in the intracellular Ca²⁺ concentration of the endothelial cells followed by the opening of Ca²⁺‐activated K⁺ channels of small and intermediate conductance and the subsequent hyperpolarization of these cells. Then, the endothelium‐dependent hyperpolarization of the underlying smooth muscle cells can be evoked by direct electrical coupling through myoendothelial junctions and/or the accumulation of K⁺ ions in the intercellular space between the two cell types. These various mechanisms are not necessarily mutually exclusive and, depending on the vascular bed and the experimental conditions, can occur simultaneously or sequentially, or also may act synergistically.