A custom mandibular distraction device for the rat

In the last several years, the rat model has been used as a reliable means of studying distraction osteogenesis (DO). This model has several benefits, including lower cost, the availability of molecular reagents for the rat, and the ability to perform a large number of operations in a short time. We have recently developed an external device that is custom-made for the rat mandible and secured at the mandibular ramus. The device consists of a Leone (Florence, Italy) jackscrew distraction assembly (0.2 mm per one-quarter turn), 2 Luhr L-shaped 0.8-mm five-hole microplates, and four 0.8-mm x 3-mm microscrews (Stryker-Leibinger Corp., Kalamazoo, MI) for fixation. Additionally, there is a methylmethacrylate block that is placed on the lingual surface of the angle of the mandible to support the posterior screws. Sterile surgical technique was used, and the same two surgeons performed all operations. To date, we have operated on 153 Sprague-Dawley rats. The procedure has been well tolerated by the animals. We had 17 postoperative deaths (11% mortality), largely as a result of anesthetic complications. There were no wound infections or dehiscence. A mandible fracture was noted in 6 rats (4%), which occurred at the time of device placement. There were no device dislodgments. Postmortem examination showed the device to be well positioned in all rats, with good callous formation at the distraction site. The rats surpassed their preoperative weight after an average of 9.2 days. These results compare favorably with those of other models currently in use. We have developed a device that is currently being used in the study of DO in the rat mandible. Our device is small in size, does not require wide undermining for its placement, and has had a low incidence of device dislodgment or infection. This model has shown great reproducibility and thus should be effective in its application for the histologic and biochemical investigation of DO in the rat.     

反复玻璃渗透对In-Ceram氧化铝基底微观结构的观察

目的 :研究In Ceram氧化铝基底在玻璃料渗透前及反复多次玻璃料渗透后样本的微观结构 ,探讨渗透次数对微观结构的影响。方法 :分别观察玻璃料渗透前、玻璃料渗透 1～ 5次的样本的SEM断面。结果 :In Ceram氧化铝烧结后 ,形成了连续开放的多孔网状结构。玻璃料渗透后 ,氧化铝颗粒之间的孔隙被渗透玻璃充盈、占据 ,二相互相锁结。结论 :In Ceram氧化铝基底在渗透前后 ,微观形貌发生明显改变 ;随着渗透次数的增加 ,渗透深度逐渐加深 ,微观结构也更为致密     

Technology Development to Explore the Relationship Between Oral Health and the Oral Microbial Community

The human oral cavity contains a complex microbial community that, until recently, has not been well characterized. Studies using molecular tools have begun to enumerate and quantify the species residing in various niches of the oral cavity; yet, virtually every study has revealed additional new species, and little is known about the structural dynamics of the oral microbial community or how it changes with disease. Current estimates of bacterial diversity in the oral cavity range up to 700 species, although in any single individual this number is much lower. Oral microbes are responsible for common chronic diseases and are suggested to be sentinels of systemic human diseases. Microarrays are now being used to study oral microbiota in a systematic and robust manner. Although this technology is still relatively young, improvements have been made in all aspects of the technology, including advances that provide better discrimination between perfect-match hybridizations from non-specific (and closely-related) hybridizations. This review addresses a core technology using gel-based microarrays and the initial integration of this technology into a single device needed for system-wide studies of complex microbial community structure and for the development of oral diagnostic devices.     

Raypex5根尖定位仪在测量根管工作长度中的临床应用

目的评价Raypex5根尖定位仪测量根管工作长度与X线法的符合性。方法用Raypex5根尖定位仪对205颗患牙共403个根管进行根管工作长度测量，以此长度进行根管预备充填后拍摄X线片观察根管充填的质量。结果Raypex5根尖定位仪测量根管工作长度后根管适充率为96．28％。结论Raypex5根尖定位仪是一种准确可靠安全有效根管工作长度测量仪器。     

Cephalometric analysis of maxillofacial morphology in unoperated cleft palate patients.

This study was designed to investigate maxillofacial morphology in adolescents and adults with unrepaired cleft palate, with or without cleft lip. Twenty-two Chinese patients with unilateral cleft lip and palate (the UCLP group), and 21 Chinese with cleft palate (the CP group) were cephalometrically evaluated and classified into the five ranges established from the means and standard deviations for matched normal Chinese populations. Many subjects in both UCLP and CP groups showed an intrinsic maxillary retrusion and a steeper mandible. The others had nearly normal maxillofacial morphology. The tendency for maxillary retrusion and a steeper mandible became increasingly remarkable with age. In the long axis of upper incisors in subjects with permanent dentition, there were no UCLP subjects with labial inclination, whereas three CP subjects exhibited labial inclination.     

冠状切口在颧骨复合体骨折中的应用

目的探讨颧骨复合体骨折复位和固定术中应用冠状切口入路的手术适应证、手术方法及减少并发症的措施。方法84例颧骨复合体骨折的患者应用单纯冠状切口为36.9%、冠状切口 下睑缘切口为32.1%、冠状切口 下睑缘切口 前庭沟切口为16.7%和冠状切口 前庭沟切口为14.3%。术中患者均使用微型钛板或小型钛板坚强内固定。对于眶底骨折出现眼球内陷的患者以羟基磷灰石人工骨进行眶底重建。结果84例患者均未发生手术后切口感染,术后随访3个月到2年,无面神经永久性损伤,术后所有咬合关系紊乱的患者均达到功能性咬合。通过训练后张口度得到满意恢复。8例患者术后患侧颧弓处仍稍显膨隆。术后眼球内陷只有1例仍大于3mm,其余均恢复满意。结论颧骨复合体骨折使用头皮冠状切口时,熟练掌握颞部的解剖层次是至关重要的,仔细保护神经及血管结构可减少手术并发症。