Detection of Vertical Root Fractures in the Presence of Intracanal Metallic Post: A Comparison between Periapical Radiography and Cone-beam Computed Tomography

Introduction

This in vitro study compared cone-beam computed tomography (CBCT) exam with different voxel sizes with digital periapical radiography in the detection of vertical root fractures in teeth with and without intracanal metallic posts.

Methods

Eighteen single-rooted human teeth were endodontically treated, prepared for cast metal posts, and artificially fractured. After positioning the teeth in dry mandibular sockets, the samples were subjected twice (with and without posts) to digital periapical radiography at 3 different angles and to CBCT examinations with 2 voxel sizes, 0.125 and 0.25 mm. The images were evaluated by 3 oral radiologists. Indices of sensitivity, specificity, and positive and negative predictive values, in addition to the areas under the receiver operating characteristic curves (accuracy), were calculated. Comparison of the accuracy of the imaging methods was assessed by using the χ² test. Comparison of the accuracy between teeth with and without posts was determined by using the Fisher exact test.

Results

The accuracy of the imaging methods showed no significant differences (P = .08). The comparison between teeth with and without posts in each examination revealed significant differences for CBCT with a voxel of 0.125 mm (P = .04) and for periapical radiography (P = .04).

Conclusions

No significant differences were observed between CBCT and periapical radiography in the detection of vertical root fractures, except for teeth with metallic posts in images from CBCT with a voxel of 0.125 mm and in digital periapical radiography. Furthermore, voxel size did not significantly influence the diagnosis of vertical root fractures.     

Influence of high expansion dental stone used as investing medium on the changes in occlusal vertical dimension of complete dentures

Problem statementDespite advances in materials and techniques, complete dentures made of acrylic resin experience an increase in the occlusal vertical dimension (OVD) during processing. Many factors that affect the OVD of complete dentures are known. However, no study has examined the effect of using high-expansion dental stone (type V) as an investing material on the OVD.PurposeThis study investigated the effects of using a high-expansion dental stone as an investing material on changes in the OVD of complete dentures.Material and methodsTwenty sets of simulated upper and lower dentures were processed by the compression molding technique. Specimens were equally divided into 2 groups. In the dental stone type III (DST III) group, the lower, middle, and upper parts of a flask were filled with DST III. In the dental stone type V (DST V) group, the procedure was the same as in the DST III group, except that the middle layer was made of high-expansion DST V. Changes in the OVD were measured before and after denture processing. Collected data were analyzed with t-test statistics. Differences were considered statistically significant at the 95% confidence level.ResultsBoth groups showed a small increase in the OVD as a result of processing, but the OVD increase was significantly less in the DST V group compared to the DST III group.ConclusionHigh-expansion DST V can be recommended as an investing material to reduce the increase in the OVD that may occur while processing complete dentures.     

咬合垂直距离降低对大鼠咬肌能量代谢的影响

目的：研究咬合垂直距离降低对大鼠咬肌能量代谢的影响.方法：40只雄性SD大鼠,随机平均分为实验组与操作对照组,依据处死时间每组再平均分为3、10、30、60d的四个亚组.采用人为降低大鼠牙冠高度的方法降低实验组大鼠咬合垂直距离,处死后取深层咬肌检测Ca^2＋-ATPase、Na^＋-K^＋-ATPase活性值改变.结果：咬合垂直距离降低后大鼠咬肌组织的Na^＋-K^＋-ATPase活性有所降低,在实验第30d时活性下降明显,但在实验第60d时与同期对照组相比差异已无显著性;Ca^2＋--ATPase活性则显示出与Na^＋-K^＋-ATPase活性相同的变化趋势.结论：咬合垂直距离降低可引起咬肌组织的能量代谢障碍,但随着低位咬合状态持续时间的延长,能量供应可得到恢复,过度的能量消耗得到缓解.     

替比夫定对乙型肝炎病毒高载量孕妇母婴传播的阻断效果及其安全性

目的 评价妊娠中晚期应用替比夫定阻断HBeAg阳性且高病毒载量孕妇母婴传播的安全性及有效性.方法 选择孕20 ～ 32周,HBeAg阳性、HBV DNA＞ 1.0× 107拷贝/ml孕妇,按患者意愿分替比夫定组和对照组,替比夫定组予替比夫定600 mg/d口服抗病毒治疗直至产后4周或产后继续服用,对照组患者不用抗病毒药物,肝功能异常者使用复方甘草酸苷.两组婴儿产后均接受主、被动联合免疫,出生后12h内、15d注射乙型肝炎免疫球蛋白200 IU及0、1、6个月注射乙型肝炎疫苗20 μg.婴儿7月龄时HBsAg及HBV DNA阳性者为HBV宫内感染. 结果 共纳入220例孕妇,其中替比夫定组120例,对照组100例.替比夫定治疗者均在美国抗逆转录酶药物妊娠登记处注册.分娩前替比夫定组孕妇HBV DNA、HBeAg、ALT水平下降明显.替比夫定组HBV DNA定量于治疗2周迅速下降,之后缓慢下降直至分娩.至分娩前替比夫定抗病毒孕妇有37例HBV DNA定量转阴,转阴率达31％ (37/120),而对照组无一例转阴.随访至7月龄,替比夫定组婴儿HBV宫内感染率为0,显著低于对照组8％ (P=0.002).替比夫定组无一例母儿因不良反应或先天性畸形失访.80例替比夫定治疗者于产后4周停药,随访至产后28周无一例发生严重肝功能损害.两组孕妇产后出血、不良妊娠、剖宫产率及新生儿胎龄、身长、体质量、Apgar评分,差异无统计学意义. 结论 HBeAg阳性、HBV DNA高滴度孕妇妊娠中晚期应用替比夫定抗病毒治疗能明显降低母亲外周血HBV DNA定量,阻断HBV母婴传播,且耐受性和安全性良好.     

Critical appraisal of studies on dentinal radicular microcracks in endodontics: methodological issues,contemporary concepts,and future perspectives

The dentinal radicular microcrack is a difficult clinical problem to diagnose and treat, and it is one of the most common reasons for tooth extraction. These microcracks start in the radicular dentin, and laboratory studies have linked crack formation to some routine endodontic procedures, namely root canal preparation, obturation, and retreatment. Most of these studies were performed using destructive methods, such as the sectioning technique, previously developed for the study of the internal anatomy of teeth. Nowadays, technological advances in the field of imaging may lead to a more thorough understanding of dentinal microcracks. This article seeks to critically appraise the methodological aspects involved in the study of dentinal radicular microcrack formation after root canal preparation, obturation, and retreatment.     

胚胎中HBV mRNA的表达与父婴传播关系的研究

目的:通过检测HBV感染父亲体外受精胚胎中的HBV mRNA以明确HBV父婴传播的意义。方法:以慢性HBV感染父亲体外受精后遗弃胚胎为研究对象,用单细胞RT-PCR检测胚胎中的HBV mRNA。结果:父亲HBV血清标志物阳性者而母亲为HBV血清标志物阴性的9例18个废弃胚胎,在1个胚胎中检测到HBVmRNA,阳性率为1/18(5.6%),84个阴性对照胚胎中未检出特异性HBV mRNA。随访发现实验组和阴性对照组之间临床妊娠率分别为33.3%和44.0%,两者之间差异无明显意义(P>0.05);早期流产率分别为33.3%和9.1%,两者之间无明显统计学意义(P>0.05);胚胎中HBV mRNA信号阳性父亲的体外受精胚胎成功种植,但发生了早期流产;两组均未发生子代HBV感染。结论:HBV mRNA的阳性结果证实了HBV可以通过精子进入早期卵裂胚胎并在其中复制,可能是父婴传播的主要途径;而且HBV可能会干扰胚胎的发育,进一步造成流产等不良结果。     

锥形束CT与根尖片对牙根纵裂诊断的对比研究

目的:比较锥形束CT(CBCT)和X线根尖片在牙根纵裂诊断中的准确度,探讨CBCT对牙根纵裂诊断的价值。方法:选取临床检查中疑似牙根纵裂患牙50例,分别进行X线根尖片、CBCT检查诊断和外科手术诊断;对X线根尖片和CBCT对牙根纵裂的诊断结果进行统计分析。结果:CBCT诊断牙根纵裂的敏感度(83.33%)高于X线根尖片诊断牙根纵裂的敏感度为(47.61%),P<0.05。结论:CBCT比X线根尖片能更准确诊断牙根纵裂,有助于牙根纵裂诊断。     

Adult umbilical hernia with vertical dislocation

We present a case of adult umbilical hernia with vertical dislocation along the abdominal wall. The hernial sac arose from the internal ring and connected to the umbilicus 20?mm below the internal ring. The postoperative course was uneventful. Two years and four months after the operation there was no evidence of recurrent hernia even when abdominal pressure was increased, and the umbilicus looked acceptable. An umbilical hernia is usually within the umbilicus. The hernial sac arose from the internal ring so should be called an umbilical hernia not an epigastric hernia. It is unusual that the umbilical hernia dislocates vertically along the abdominal wall, while the umbilicus stays depressed. This atypical form of umbilical hernia has not been described previously as far as we know.     

Is natural conception a valid option for HIV-serodiscordant couples?

The remarkable reduction in HIV-related morbidity and mortality as a consequence of the widespread use of highly active antiretroviral therapy (HAART) has led to a growing number of HIV-infected persons and their partners requesting counselling regarding the chances of reproduction. A thoughtful medical evaluation of the couple, which should entail HIV status, screening for genital infections and fertile potential, is needed before considering any reproductive attempt. Given that both sexual and perinatal transmission of HIV is directly correlated with the level of viral replication, being almost negligible in patients with undetectable viremia, HAART should be given to the infected partner to minimize the risk of transmission. Assisted reproduction after 'sperm washing' may further reduce the chances of infection, although this is not within reach or desire for a significant number of HIV-serodiscordant couples. From our perspective, natural conception could now be considered a possible alternative for HIV-serodiscordant couples, as long as complete suppression of viremia with HAART is achieved in the infected partner. The objective of this paper is to propose a protocol that may minimize risks in HIV-discordant couples that have opted for natural conception.