Immediate precision of the digital osteotomy template in the digital stackable template: a clinical study / 华西口腔医学杂志

OBJECTIVES@#This study aimed to evaluate the immediate accuracy of the digital osteotomy template in the digital stackable template.@*METHODS@#From November 2018 to January 2020, 4 patients with dentition loss were selected from the Prosthodontics Department, West China Stomatological Hospital. All patients met the conditions for immediate planting and immediate restoration. Owing to the lack of vertical target-restoration space, the implantation plan included intraoperative osteotomy. According to the preoperative cone beam CT (CBCT) data, combined with aesthetic digital smile design (DSD) analysis, virtual wax design, and so on, the ideal bone plane design was performed. According to the virtual osteotomy plane, the virtual implantation plan was designed, and then the digital stackable template assuming osteotomy template, implantation guide, and temporary restoration were made and 3D printed. Osteotomy was performed under the guidance of digital osteotomy template during the operation. The preoperative CBCT and postoperative CBCT of all patients overlapped, the deviation between the actual osteotomy and the ideal osteotomy was calculated, and the angle deviation between the postoperative bone plane and the ideal bone plane was measured.@*RESULTS@#The ave-rage volume deviation between the postoperative design and the ideal one was 492.94 mm³, accounting for 21.21% of the preset osteotomy volume. The average deviation between the postoperative osteotomy and the ideal osteotomy in four patients was 0.024 8 mm. The average angle between the postoperative bone plane and the ideal bone plane was 6.03°.@*CONCLUSIONS@#The displacement deviation of virtual osteotomy design and the actual osteotomy one under the guidance of digital osteotomy template in the digital stackable template are highly consistent with the original design. Thus, this clinical technique is worth popularizing, accurate, and quantifiable.

Precise implant insertion technology for measuring dental implant placement / 华西口腔医学杂志

Identifying the ideal implantation site is important for the long-term stability and effectiveness of follow-up restorations. Implant surgical guide and navigation are used to determine the implantation site in clinic and improve the precision of implantation. However, due to difficulties in digital methods, such as multiple procedures, high cost, and actual accuracy of more than 1 mm, many physicians still prefer to operate with free hand. In preoperative, intraoperative, and postoperative procedures, time-saving and practical methods for implant site evaluation are lacking. In many cases, oral physicians found that the position deviates only by cone beam CT, which was costly to modify the position. In this article, we presented a precise implantation insertion technology that is guided by a measurable technique throughout the implantation application for all implant systems. This method was guided by a dynamic control measuring ruler, which functions together with the measuring and intraoperative locating rulers. The 3D space of the operative area was measured by a measuring ruler prior to operation, and the implant plan and quantitative guidance design were conducted according to the measured and cone beam CT data. The whole implantation process was guided by the dynamic control measuring ruler, and measuring verification results were also considered. This method can realize the quantification of the entire preoperative space analysis, intraoperative precise implantation guidance, and postoperative site measurement and evaluation. This practical technique also helps to adjust the position, improve the implantation accuracy and is suitable in generalizing dental implantation.

Uprighting a mesially tilted mandibular second molar by using a dental implant as anchorage: a case report / 华西口腔医学杂志

After tooth has been removed for a long time, adjacent teeth may tilt to occupy the edentulous space, leading to a break in the occlusal 3D equilibrium and a lack of restorative space. This case report presents a mandibular second molar uprighting with anchorage from a dental implant.

The protective effects of ischemic preconditioning on reperfusion injury of rat lung / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of ischemic preconditioning on reperfusion injury of rat lung.</p><p><b>METHODS</b>Rat isolated lungs (n=8 in each group) were stabilized and perfused by Krebs-Henseleit solution on a modified langendorff perfusion apparatus. 36 wistar rats were divided into three groups: ischemic preconditioning group, ischemia/reperfusion group and control group. Mean pulmonary artery pressure, wet/dry ratio, pulmonary surfactant phospholipid and alveolar surface tension in bronchoalveolar lavage fluid and electron microscope were detected.</p><p><b>RESULTS</b>The morphological changes of lung injury were alleviated in the preconditioning group under electron microscope. Wet/dry ratio, mean pulmonary artery pressure and SA/LA ratio were significantly lower in the preconditioning group after ischemic/reperfusion (P < 0.01). Total phospholipid and large aggregate in the BALF were significantly increased in the preconditioning group (P < 0.01). Small aggregate showed no change in three groups. Surfactant activity test showed that surface tension markedly decreased in IPC group (P < 0.01).</p><p><b>CONCLUSION</b>These results indicates that ischemic preconditioning may have a protective effect in ischemic/reperfusion injuries lung by ameliorating the content and function of surfactant phospholipid.</p>