颅底结构螺旋CT影像的三维定量测量

目的　分析健康成人当下颌骨处在正常牙尖交错位时 ,髁突与颅底颈内动脉管外口、颈静脉窝、卵圆孔、棘孔、破裂孔等之间的空间位置关系 ,为术中对其他重要结构的位置评估提供依据。方法　选择健康成人 10 0名 ,在正常牙尖交错位时 ,用螺旋CT扫描、颅底三维影像重建 ,测量各结构间的最短距离和空间角度。 12个定点 ,测量 2 8项距离和空间角度以极坐标表示 ,髁突内缘点为中心点 ,髁突长轴为 0°轴作为参照系。结果　颌下入路能顺利显露髁突内缘点和髁突长轴的方向 ,以此为参照系 ,确定颈内动脉管外口外缘点为 12 0 1± 2 71mm ,5 14± 1 2 2° ,颈静脉窝外缘点为 15 11±2 72mm ,- 5 6 2 7± 14 0 5°。结论　以髁突内缘点为中心点 ,髁突长轴为 0°轴参照系有助于为颌下入路颅底手术的术中定位及颅底解剖教学提供参考。     

三维CT在颅颌巨大肿瘤诊治中的应用

三维ＣＴ在颅颌巨大肿瘤诊治中的应用姜晓钟，高宏，陈必胜，刘渊，张沉石，杨中坚三维ＣＴ成像是近年来影像学的一门新技术。它将普通ＣＴ二维平面的断层扫描重建为立体的三维图像，减免了临床医师对二维图像的思维综合，为临床肿瘤的诊治提供了确实可靠的资料，也为肿瘤...     

三维CT在颌面骨折中的应用

目的：评价三维CT影像技术在颌面骨折诊断及治疗中的应用。方法：对18例颌面骨折患者进行三维CT和二维CT检查，通过外科手术验证三维CT诊断的准确性。结果：三维CT成像能立体、精确、多方位地显示骨折部位、范围、移位、旋转、骨缺损范围等情况。结论：三维CT对颌面部骨折后畸形的检查具有独特的诊断价值，同时对手术方案的制定具有指导意义，并能够细化手术方案。     

三维CT在颌骨骨折中的应用

目的：探讨三维ＣＴ成像技术在面中部骨折中的应用价值,尤其是对凳面部复合,多发骨折的术前诊断和手术计划制定的意义。方法：对４７例面中部骨折进行螺旋ＣＴ扫描和三维成像。结果：４７例例患者中３８例经手术治疗,９例为保守治疗,所有手术病例都证实了术前三维ＣＴ的诊断,结论：三维ＣＴ成像可使颌面部复杂性骨折的移位情况近似模型殷再现,有益于选择最合适的手术方案。     

三维CT在口腔医学中的应用

三维CT能清晰显示解剖结构的三维立体影像,可精确测量其表面积、体积、距离等数据,在口腔科中的应用日趋增多,本文就三维CT在口腔医学中的应用进行综述。     

三维CT成像在颌骨疾病诊断中的应用

三维ＣＴ在口腔颌面部骨组织疾病诊断的临床应用研究揭示：三维ｃＴ成像是以人们所熟悉的方式，立体地显示骨组织结构和病变，显示人体复杂区域的解剖关系，提高了观察者对二维图像病变的认识能力。简化了大脑思维综合过程。三维ＣＴ通过不同轴面的旋转以及切割方法，立体地表现其本身及其与周围组织的关系，对诊断和治疗提供了积极有益的帮助。     

三维CT在颌骨肿瘤中的应用

目的 :探讨三维CT成像技术在颌骨肿瘤中的临床应用价值。方法 :对 17例颌骨肿瘤进行螺旋CT扫描成像 ,8例做了增强扫描 ,全部病例均手术和病理证实。结果 :全部病例能清楚地显示颌骨肿瘤的骨质改变及与邻近结构关系的立体解剖图像。结论 :三维CT简化了观察者的思维过程 ,可直观地了解颌骨肿瘤在三维空间的破坏范围与周围结构的关系 ,特别对已波及颅底的颌骨肿瘤诊断价值最大 ,能帮助确定手术中骨质切除或保留的量 ,为手术计划的制定提供依据。     

三维CT在颌面部骨折诊治中的应用

目的 探讨三维ＣＴ在颌面部骨折诊治中的临床应用。方法 对３例颌面复杂骨折患者,进行三维ＣＴ体积重建。结果 三维ＣＴ影像可以任意旋转和切割,从不同的角度,直观精确地显示骨的移位情况,为诊断和制订手术方案提供了有益的像资料。结论 三维ＣＴ在凳面部骨折诊治中有很大的应用价值。     

切除翼上颌及颅中窝底肿瘤的一个新手术进路(5例报告)

目的　介绍切除翼上颌及颅中窝底肿瘤的一个新手术进路。方法　从上唇红唇向上达患侧鼻孔底 ,然后向外绕鼻翼向上达内眦 ,向外达耳屏前向上作半冠状切开。向下及向中线在骨膜下分别翻转颊瓣及头皮瓣。截除上颌骨、眶下及额颞颅底之颅骨后 ,肿瘤完全暴露 ;摘除肿瘤后 ,用微型夹板固定骨块。分层缝合复回之组织瓣。结果　可获得从对侧咽鼓管到同侧膝状神经节 ,包括鼻咽、斜坡、蝶窦、翼静脉丛及颞下窝和眶上裂在内的良好暴露。用本进路对 5例患者进行了治疗 ,全部一期愈合。结论　本进路对包括鼻咽、斜坡、眶上裂、颞下窝及翼腭窝在内的肿瘤病变特别有用。     

Le FortⅠ型截骨入路在颅底肿瘤切除中的应用

目的　为了寻求颅底斜坡区及其前方鼻咽部和蝶窦区肿瘤手术切除的最佳入路途径。方法　根据术前MRI所示肿瘤所在的部位和大小 ,采用LeFortⅠ型截骨进路对 1 6例该区域的肿瘤进行了手术切除 ,其中脊索瘤 8例 ,血管纤维瘤 2例 ,软骨瘤、骨髓瘤、垂体瘤、骨纤维结构不良、腺癌和粘液囊肿各 1例。结果　本组 1 6例颅底肿瘤 ,全切除 1 1例 ,次全切除 5例 ,随访 6～ 4 0个月。 4例局部复发 ,其余患者恢复良好。上颌骨复位后 ,咬合关系均恢复良好。结论　采用上颌截骨入路切除颅底肿瘤 ,较传统的前方或侧方入路对脑组织的损伤小 ,手术视野暴露清楚 ,无严重及长期的并发症发现     

EFFECT OF THERMOCYCLING ON THE TENSILE AND SHEAR BOND STRENGTHS OF THREE SOFT LINERS TO A DENTURE BASE RESIN

Statement of problem

In clinical practice, loss of adhesion between the silicone-based denture liner and the denture base resin is always an undesirable event that might cause loss of material softness, water sorption, bacterial colonization and functional failure of the prosthesis.

Purpose

This study evaluated the effect of thermocycling on tensile and shear bond strengths of three soft liner materials to a denture base acrylic resin.

Material and methods

Three resilient liners (Mucopren-Soft, Mollosil-Plus and Dentusil) and a heat-polymerized acrylic resin (QC-20) were processed according to manufacturers’ directions. Sixty specimens (14 x 14 mm cross-sectional area) per bond strength test (20 for each liner) were fabricated and either stored in water at 37°C for 24 hours (control groups; n=10) or thermocycled 3,000 times in water between 5°C and 55°C (test groups; n=10). The specimens were tested in tensile and shear strength in a universal testing machine until fracture. Bond strength means were compared between water-stored and thermocycled groups for each material, as well as among materials for each treatment (water storage or thermocycling). Failure mode (adhesive, cohesive and mixed) after debonding was assessed. Data were analyzed statistically by paired Student’s t-test and ANOVA at 5% significance level.

Results

The water-stored groups had statistically significant higher bond strengths than the thermocycled groups (p<0.05). Without thermocycling, Mucopren-Soft (2.83 ± 0.48 MPa) had higher bond strength than Mollosil-Plus (1.04 ± 0.26 MPa) and Dentusil (1.14 ± 0.51 MPa). After thermocycling, Mucopren-Soft (1.63 ± 0.48 MPa) had the highest bond strength (p<0.05).

Conclusion

The bond strength of the three soft denture liners tested in this study changed with their chemical composition and all of them exhibited higher bond strengths than those usually reported as clinically acceptable.

Clinical Implications

All soft lining materials tested in this study showed a significant decrease in the bond strength to an acrylic denture base resin after thermocycling. In spite of thermocycling, though, the silicone-based liners had satisfactory bond strengths for clinical application.     

鼻咽癌在口腔颌面外科误诊的临床分析

目的　分析鼻咽癌临床误诊的原因从中吸取教训。方法　回顾性分析 6例病例。结果　误诊原因为 6例病人中 2例未及时作鼻咽部活检 ;2例因病灶位置隐蔽 ,经多次鼻咽部检查方才确诊 ;有 2例鼻咽部虽然经多次检查仍为阴性而取颌下肿块作了活检证实为转移癌灶。结论　鼻咽癌诊断困难原因主要有医生对此病警惕性不够和症状及体征不典型 ,活检取材位置不正确和深度不够。对面颈部包括腮腺区及颌下、颏下肿块患者要仔细检查鼻咽部 ,多次、多部位深取材活检才能得出正确的诊断。以及对鼻咽部多次检查阴性而腮腺区、颌下、颏下肿块增大迅速及时进行肿块组织学检查     

EFFECT OF POST-POLYMERIZATION HEAT TREATMENTS ON THE CYTOTOXICITY OF TWO DENTURE BASE ACRYLIC RESINS

Introduction:

Most denture base acrylic resins have polymethylmethacrylate in their composition. Several authors have discussed the polymerization process involved in converting monomer into polymer because adequate polymerization is a crucial factor in optimizing the physical properties and biocompatibility of denture base acrylic resins. To ensure the safety of these materials, in vitro cytotoxicity assays have been developed as preliminary screening tests to evaluate material biocompatibility. ³H-thymidine incorporation test, which measures the number of cells synthesizing DNA, is one of the biological assays suggested for cytotoxicity testing. Aim: The purpose of this study was to investigate, using ³H-thymidine incorporation test, the effect of microwave and water-bath post-polymerization heat treatments on the cytotoxicity of two denture base acrylic resins.

Materials and Methods:

Nine disc-shaped specimens (10 x 1 mm) of each denture base resin (Lucitone 550 and QC 20) were prepared according to the manufacturers'' recommendations and stored in distilled water at 37°C for 48 h. The specimens were assigned to 3 groups: 1) post-polymerization in a microwave oven for 3 min at 500 W; 2) post-polymerization in water-bath at 55° C for 60 min; and 3) without post-polymerization. For preparation of eluates, 3 discs were placed into a sterile glass vial with 9 mL of Eagle''s medium and incubated at 37°C for 24 h. The cytotoxic effect of the eluates was evaluated by ³H-thymidine incorporation.

Results:

The results showed that the components leached from the resins were cytotoxic to L929 cells, except for the specimens heat treated in water bath (p<0.05). Compared to the group with no heat treatment, water-bath decreased the cytotoxicity of the denture base acrylic resins.

Conclusion:

The in vitro cytotoxicity of the tested denture base materials was not influenced by microwave post-polymerization heat treatment.     

高频超声检查在颌面部非金属异物中的应用价值

目的　探讨超声在颌面部非金属异物定位诊断中的价值和引导手术的意义。方法　采用高频超声对颌面部 33例患者 7种非金属异物的声像图特征及探查定位情况进行总结分析 ,并与手术后结果进行对照。结果　 33例患者颌面部非金属异物共 5 2块 ,超声明确诊断并清晰定位 4 7块 ,定位诊断准确率 90 .4 %。对翼颌间隙、眶内及上颌后区的异物 ,超声诊断准确率受到一定的限制 ,5块诊断不准确。术前超声引导穿刺针定位或美兰标记异物 9块 ,手术顺利取出 9块 ;术中超声定位异物 11块 ,引导手术顺利取出 11块 ;超声引导手术成功率 10 0 %。结论　超声对软组织非金属异物图像显示清晰 ,定位准确 ,引导手术方便有效 ,对临床治疗和制定手术方案具有重要的指导意义。对翼颌间隙、眶内及上颌后区的异物应结合MRI检查     

唇腭裂新生儿颅基底形态结构特征的研究

目的　在唇腭裂新生儿三维重建体上研究颅基底形态结构特征。方法　采用计算机辅助三维重建技术 ,对 6例正常胎儿及 5例唇腭裂新生儿标本颅基底形态结构作立体定量的分析比较。结果　唇腭裂患儿颅底角无明显异常 ,而后颅底长增加 ,前颅底倾斜度减少 ,双侧完全性唇腭裂还表现出前颅底长、宽均有异常。结论　研究结果表明颅基底异常是唇腭裂畸形的综合表现之一。     

CRITERIA ADOPTED BY DENTISTS TO INDICATE THE EXTRACTION OF PERIODONTALLY INVOLVED TEETH

When dealing with patients with periodontal disease of variable severities, dentists must often choose between treating and restoring the involved tooth or indicating its extraction. Different criteria have been adopted in this decision-making process. The purpose of this study was to evaluate the criteria adopted by dentists to indicate the extraction of teeth with periodontitis. Dentists were interviewed at their private practices in three cities of the state of Rio Grande do Sul, Brazil. The evaluated criteria included severity of attachment loss, tooth mobility, furcation involvement, prosthetic planning, periodontal-endodontic lesion, possible systemic involvement due to the presence of periodontitis, referral to a periodontist for evaluation, radiographic bone loss greater than 50%, presence of extensive caries, socio-economic and cultural status of the patient, among others. The most often adopted criteria to indicate the extraction of periodontally affected teeth were the presence of mobility (37.5%), severity of attachment loss (24.3%) and radiographic bone loss greater than 50% (21.2%). The results of the present study demonstrated the difficulties faced by dentists to indicate the extraction of teeth with severe attachment loss, in addition to the establishment of an adequate prognosis. Aspects associated with the past disease were still the most often reported to indicate the extraction of teeth for periodontal reasons.