根管显微镜在定位上颌磨牙近颊根第二根管中的作用

目的:评价改进开髓口和应用根管显微镜(DOM)定位离体上颌第一、二磨牙近颊根第二根管(MB2)的能力.方法:收集离体上颌第一、二磨牙共550颗.在肉眼、传统三角形开髓口(N.E-1),肉眼、改进开髓口(N.E-2)和根管显微镜辅助(DOM)三种不同条件下分别探查根管,记录MB2数目.结果:N.E-1、N.E-2和DOM三种不同条件下,MB2发现率在上颌第一磨牙分别为34.26%、51.85%和78.24%;第二磨牙分别为16.17%、23.65%和41.32%.改进开髓口和使用DOM可显著提高MB2发现率,与传统开髓口间的差别有统计学意义,P＜0.05.结论:建议将上颌磨牙开髓口由传统的三角形改为斜四边形,并使用合适的放大技术和增强照明,以提高MB2发现率和治疗率.     

Anorectal amelanotic melanoma

Objective  Anorectal melanoma is a rare, highly malignant tumour with a poor 5 year survival of 10%. Most anorectal melanomas have gross and/or histologic pigmentation, however about 30% of anorectal melanomas are amelanotic.
Method  We report three cases of amelanotic anorectal melanomas and integrate our data with six case reports of amelanotic malignant melanoma from the literature. Further we compare clinicopathological data and clinical outcome with large series of anorectal melanomas (both, amelanotic and pigmentated).
Results  There were seven females and two males, of median age 62 years (range: 45–75 years). Rectal bleeding was the leading symptom in all cases with a mean duration of 4 months before diagnosis. Eight of nine patients developed distant metastases. Median survival was 14 months (range: 3–60 months). A tumour thickness of < 4 mm was correlated with long-term disease-free survival, whereas tumour thickness of 4 mm or more was correlated with systemic recurrence.
Conclusion  Early diagnosis is key for efficient treatment and improved survival rate for patients with this unusual variant of melanoma. There is no difference in terms of age, time of diagnosis, stage and survival between pigmented and amelanotic anorectal melanoma.     

Periapical reactions to calcium hydroxide-containing sealers and AH 26® in monkeys

Abstract The long-term effect on periapical healing (8-14 months) of CRCS® and Sealapex® was compared with that of AH 26®. Vital pulpectomy and root canal filling by the hybrid ther-momechanical method were performed in teeth of 3 young monkeys. Ten roots with CRCS, 10 with Sealapex and 7 roots with AH 26 were examined after demineralization and routine histological processing. Hematoxylin and eosin and Brown & Brenn staining for micro-organisms were employed. Mild to severe inflammatory lesions were found at the apical foramina of the roots filled with AH 26 and CRCS. Most of the Sealapex specimens showed no inflammatory cells, except macrophages with sealer particles. A striking finding was a tendency towards apical obliteration with calcified tissue in roots filled with Seal-apex, apparently following resorption of the sealer. Such a tendency was seldom observed with the other sealers. However, both AH 26 and Sealapex were irritating for a long time when pushed into bone. Despite the interesting results with Sealapex, additional research is needed before its use can be unconditionally recommended. This sealer has not yet been tested in infected cases and its ability to be resorbed, which is an advantage when it precedes replacement by calcified tissue, may become a disadvantage if it is not followed by apical obliteration.     

副根管的实验观察及其临床意义

目的：观察副根管的发生率。方法：利用透明标本的制作及0．5％碱性品红在髓室底的渗入情况，判断副根管的有无。结果。透明标本与染料渗入法显示第一，二恒磨牙副根管的发生率分别为12．96％，20．45％，经卡方检验，两者差异无显著性。结论：副根管是药物渗漏及致病菌侵犯的通道，临床诊疗时应予以考虑。     

Healing process of dogs' pulpless teeth after apicoectomy and root canal filling at different levels

Abstract Dogs' teeth with infected root canals, were submitted to apicoectomy and the root canals were filled flush or 2 mm short. In a third group the canals were left unfilled and only the access openings were closed. One hundred and eighty days after the treatment, the animals were killed and the specimens prepared for histological analysis. Repair was not observed in the teeth with unfilled root canals. The healing observed in the teeth with root canals filled flush was less complete than the healing observed when the root canals were filled 2 mm short.     

硫酸镁在骶管封闭治疗腰椎间盘脱出中的应用

应用25%的硫酸镁10ml、2%利多卡因5ml、确炎舒松 A20mg 和维生素 B_(12)0.5mg 行骶管封闭,结合卧床休息治疗腰椎间盘脱出引起的坐骨神经痛30例,结果优10例,良17例,优良率为90%。作者认为高渗硫酸镁(12.5%),具有迅速脱水、消肿和止痛的功效,该法具有显效快,无副作用,经济方便等特点。     

Morphological correlations between spontaneously discharging primary vestibular afferents and vestibular nucleus neurons in the cat

Synaptic connections between physiologically classified primary vestibular afferents (PVAs) and their target vestibular nucleus (VN) neurons were examined by a combination of intra-axonal staining and electron microscopic techniques. PVAs originating from the horizontal semicircular canal were electrophysiologically classified as either regular- or irregular-type based on the regularity of their spontaneous discharge patterns, and were intra-axonally labeled with horseradish peroxidase (HRP). HRP-labeled PVAs of both types had many swellings along their course that contacted VN neurons. These swellings contained spherical synaptic vesicles and showed asymmetric postsynaptic specialization. Target VN neurons of both types of PVAs were distributed primarily in the superior, medial, and inferior VN. Irregular-type PVAs made more axosomatic contacts than did regular-type PVAs. The soma size of target VN neurons and the number of terminal boutons per target VN neuron were larger for irregular-type PVAs than for regular-type PVAs. Large VN neurons (presumably kinetic neurons) were innervated exclusively by irregular-type PVAs. Small VN neurons were innervated by PVAs of the regular-type and the irregular-type. These results demonstrate that there is a correlation between the physiological properties and morphological characteristics of PVAs and their target VN neurons. © 1993 Wiley-Liss, Inc.     

The application of the buccal object rule for the determination of calcified root canals

Root canal calcification represents a serious problem which often occurs in clinical practice. Calcified root canals are difficult or even impossible to find and treat conservatively. In this paper, a technique is proposed which may be helpful in detecting and locating calcified root canal(s) and properly treating them. The proposed technique is simple and easy to perform in posterior and anterior teeth, and it may be useful in everyday clinical practice.     

Cutting characteristics of a sonic root-end preparation instrument

Abstract The aim of this study was to investigate the culling ability of retro tips powered by a sonic handpiece (MM 1500, Micro Mega, Prodonta, Geneva, Switzerland). Two levels of the following variables were evaluated in this study: a) power selling with the air inlet ring half or fully open, b) orientation of lip perpendicular or parallel to the long axis of the handpiece, c) length of tip 2 or 3 mm, d) loading of 25 or 50 grams, e) tip size 35 or 55. The substrate used was 1 mm thick set lions of bovine bone and load was controlled by using a load cell interfaced with a transducer meter. Instrumentation time was fixed at 10 seconds with water irrigation. A 2⁵ full factorial analysis was performed with two replications making a total of 64 experimental units. The resultant depth of cm was measured using a stereo microscope at x50 magnification. Analysis of the data indicated that all variables had a significant effect on cutting (ANOVA p<0.05). The most significant factor was power, followed by tip length, tip orientation, width and load. An increase in loading resulted in tip constraint and a reduction of culling at the lower power selling. In conclusion sonic ally activated retro tips were found to cut satisfactorily with instrument air inlet ring opening/power having the main effect.