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锥形束CT是一种临床辅助检查方式,它可以提供高质量、高精度的颌面部三维图像。因其图像精度高、扫描时间短、辐射剂量小等优势,在口腔临床医学中得到广泛应用。本文对锥形束CT在牙体牙髓疾病领域的应用进展做一综述。     

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口腔颌面部骨组织结构是支撑面型的重要基础,发生在口腔颌面部的外伤、肿瘤、先天畸形是引发患者口腔颌面部骨组织缺损的主要原因,而如何在一期对患者面型及骨组织缺损进行修复也是口腔颌面外科手术中亟待解决的重点和难点问题。本文主要总结了口腔颌面部骨组织缺损修复材料的发展。     

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目的对上颌前牙区颌骨的骨量及唇侧骨皮质厚度进行测量分析,为正畸治疗植入微种植支抗钉的安全区提供参考依据。方法对2010年9月至2011年6月来大连市口腔医院就诊的25例成人患者行锥形束CT扫描及三维重建,测量距上颌牙槽嵴顶3、6、9、12mm4个水平上颌中切牙、侧切牙、尖牙根间区近远中向、唇腭向的距离以及唇侧骨皮质厚度。结果 (1)在距上颌牙槽嵴顶3、6、9mm水平中切牙根间近远中向距离均最宽,唇侧骨皮质均最薄;(2)在距牙槽嵴顶9mm水平中切牙与侧切牙根间近远中向距离最窄;(3)在4个测量水平侧切牙与尖牙根间唇侧骨皮质均最厚;(4)唇腭向在距牙槽嵴顶9mm及以上水平,中切牙根间骨厚度最薄,中切牙与侧切牙根间骨厚度最厚。25例中仅3例前牙区各牙根长度超过12mm,在距牙槽嵴顶12mm水平能测出根间近远中向距离,均较宽。结论通过对扫描后颌骨影像的分析,明确了前牙区颌骨的骨量及唇侧骨皮质厚度,为植入微种植支抗钉的安全区提供参考依据。     

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??Objective    To measure the anatomic buccolingual angulation values of the maxillary alveolar process based on CBCT images in order to form a basis for the implant treatment planning?? including the design of implant position and angulation. Methods    A random sample of 51 CBCT images were selected and analyzed. The NewTom 5G CBCT data sets were reformatted at a 0.5-mm spacing?? with the inferior border of the region of interest parallel to the occlusion plane of maxillary teeth. Twenty-four buccolingual cross-sectional images of the maxillary alveolar process were obtained for buccolingual angulation measurements. Results    Mean or median values of the buccolingual angulation of maxillary alveolar process ranged from about 0 degree to more than 40 degrees. Cross-sections distal to the premolar region showed a statistically higher proportion of vertical process ??angulation equals to 0 degree???? compared to cross-sections corresponding to maxillary premolars and anterior teeth region ??P < 0.05??. There were no statistical differences between the angulation of alveolar process both from the right side and left side and from males and females patients ??P > 0.05??. Conclusion    The buccolingual angulation of maxillary alveolar process decreases from anterior teeth region through the premolars region to the molars region?? with the lateral incisor and canine region being the most inclined bucally and a high proportion of the molars region being nearly vertical. Knowing average values of buccolingual angulation of maxillary alveolar process before dental implantation may help the clinician plan the position and orientation of implants?? especially when an implant surgical template is not available.     

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??Objective    To measure the anatomic buccolingual angulation values of the mandibular alveolar process based on CBCT images in order to help determine the implant angulation at the implant treatment-planning phase. Methods    A random sample of 51 CBCT images were selected and analyzed. The NewTom 5G CBCT data sets were reformatted at a 5-mm spacing??with the inferior border of the region of interest parallel to the base of the mandible. Twenty-four buccolingual cross-sectional images of the mandibular alveolar process of each CBCT scan were obtained for angulation measurements by NNT5.6 software. Results    The mean or median values of the buccolingual angulation of the mandibular alveolar process??ranging from 1.8 degrees to 28.5 degrees??were obtained. There were no statistically significant differences on the angulation values of the alveolar process between the right side and left side or between male and female patients??P??0.05??. The number of buccally-inclined alveolar process cross-sections increased from cross-section NO.8 to NO.11??and decreased from cross-section NO.14 to NO.17??which were statistically significant??P??0.05??. Conclusion    The mean or median values of the buccolingual angulation of mandibular alveolar process increase gradually from the anterior tooth region via the premolar region to the second molar region. Most of the mandibular alveolar process cross-sections at the anterior teeth region incline buccally??while most of those at the premolar region and all of those at the molar region incline lingually. Knowing buccolingual angulation values of the mandibular alveolar process before dental implantation may help the clinician plan the orientation of implants.     

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??Gelatinases are the fundamental components of matrix metalloproteinases??including matrix metalloproteinase-2 and matrix metalloproteinase-9??and have the ability to degrade extracellular matrix. Recent studies have shown that gelatinases play an essential role in the pathogenesis of pulpitis and apical periodontitis. This paper makes a review on recent advances of the basic research of gelatinases and their effects on the pathogenicity??the diagnosis as well as the therapy for pulpitis and apical periodontitis.     

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颅面生长是遗传和环境因素共同作用的结果,咀嚼肌功能被认为是调节颅面生长发育的重要环境因素,它与颅面形态相互作用,使颅面复合体始终处于一种动态平衡之中.本文就近年来有关咀嚼肌形态和功能与颅面形态关系的研究进展做一综述.     

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??Objective    To evaluate the clinical effect of cone beam computed tomography??CBCT??as an adjunctive therapy of endodontic treatment for calcified canals??and discuss the clinical significance. Methods    Three hundred and seventy-four teeth were selected??which needed to get the root canal therapy??and all of them were blocked with calcification completely in x-ray. The 185 calcified canals that could not be negotiated during the conventional root canal therapy were treated under the endodontic microscope combined with ultrasonic instruments. The negotiation rates were calculated. After that??the 46 canals which could not be negotiated continued to be treated with the help of CBCT??and the negotiation rates were calculated. Results    During the conventional root canal therapy??374 teeth were treated??185 root canals were not negotiated. After that??these blocked canals were treated under the endodontic microscope combined with ultrasonic instruments. Totally 139 canals were negotiated and the negotiation rate was 75.14%??27 root canals were seen in the CBCT images??and 19 root canals were not. The former included 11 thin root canals??9 canals whose orifices were blocked and 7 canals whose negotiating direction was deviated. With the help of microscope and ultrasonic instruments??all of the 27 blocked canals were treated successfully. The success rate was improved to 89.72%. Conclusion    CBCT images can assist to locate the root canal orifice??and show the direction of calcified canal and canal morphology. To some extent??it can improve the negotiation rate of the calcified root canals.     

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??Objective     To explore the value of cone-beam computed tomography??CBCT??in diagnosing complicated periapical diseases. Methods    Forty teeth were studied. X-ray periapical images??taken at horizontal 0°and distal 10° angulated projection??and CBCT were taken at the same time. The presence of apical lesions and their extents??if existed??were observed??periapical index??PAI??scoring system was used for assessing lesions extent. Compare the difference on diagnosis and judgement of causes. Results    Disagreement was found between X-ray periapical image and CBCT in lesions assessment and PAI scoring. More valuable information was obtained by CBCT. Conclusion    CBCT is a very useful tool in the diagnosis of complex periapical diseases.     

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烤瓷熔附金属全冠(porcelain-fused-to-metal,PFM)也称金属烤瓷全冠,是一种由低熔烤瓷真空条件下熔附到铸造金属基底冠上的金一瓷复合结构的修复体.烤瓷熔附金属全冠兼具有金属全冠的机械强度好和全瓷冠美观的优点[1].     

钛种植体骨结合界面组织学研究进展

随着种植体骨结合理论的提出及钛种植材料的应用,口腔种植学得到突飞猛进的发展。目前,种植体5年成功率已达95%以上,但临床失败病例也偶有发生;同时,因骨结合需要一定的时间,故近年来,对于如何促进种植体骨结合的形成、缩短种植治疗周期、确保种植体持久稳定地行使功能,成为学者们研究的重点。目前,应用动物实验模型进行种植体-骨界面的生物力学及组织学研究成为主要的研究方法之一。本文主要就种植体骨结合过程、种植体-骨界面组织形态计量学及显微CT在种植体-骨界面研究中的应用现状做一综述。     

不同愈合时间下挤压植入种植体对Beagle犬骨界面改建的组织形态学测定

目的：研究不同愈合时间下挤压植入微种植体对其周围骨界面改建的影响。方法：采用自身对照原则,将36枚微种植体植入6只成年Beagle犬上颌后牙区。左右各植入3枚种植体,一侧为实验组以骨挤压植入,对侧为对照组。每侧随机分配植入不同愈合时间（2周,4周和8周）的种植体,取带有种植体骨标本制备不脱钙的超硬组织切片,采用组织形态学定量测定的方法,对钛种植体骨界面改建过程进行动态观察,从定量的角度分析其变化的差异。结果：实验组与对照组种植体骨接触率均随愈合时间的延长而增加。实验组愈合2周,4周时种植体骨接触率明显高于对照组,8周时趋于一致。实验2周组与8周组种植体骨接触率表现出显著性差异,对照2周组与4周组存在显著性差异。结论：愈合早期骨挤压可以提高种植体骨整合率,提示需要早期加载的微种植体以骨挤压术式植入可提高种植体稳定一I生。     

皮质骨厚度对支抗种植体-骨界面应力分布的影响

目的：研究皮质骨厚度改变对支抗种植体-骨界面应力分布的影响，供临床参考。方法：用三维有限元方法，对分别种植于皮质骨厚度为0．5mm、1．0mm、2．0mm颌骨模型中的种植体施加150g近远中方向的载荷，分析支抗种植体-骨界面应力分布情况：结果：三者种植体颈部的Von-Mises应力值分别为0．6040MPa、0．5330MPa、0．5380MPa；位移值分别为0．2110μm、0．1630μm、0．1250μm：结论：皮质骨在一定厚度内，植入体颈部皮质骨越薄，骨界面应力值就越大：但皮质骨超过一定厚度后，骨界面应力并不随其厚度的增加而做相应递减。皮质骨的厚度与界面骨的位移成反比.     

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目的研究改进的超硬组织切片技术应用于钛种植体骨界面研究中的关键步骤及需注意的问题。方法本研究于2012年8—11月在山西医科大学动物实验中心完成。选用6只成年雄性Beagle犬,在上颌牙槽骨分别植入6枚种植体后,锯下带有种植体的牙槽骨,采用改进超硬组织切片技术制作切片并进行染色观察。结果60～80μm厚的切片上通过甲苯胺蓝染色可以观察到骨组织的微细结构、种植体与骨组织的结合情况以及胶原纤维和类骨质。结论改进的超硬组织切片技术适合种植体与骨组织结合情况研究。     

支抗种植体长度对骨界面应力分布的影响

目的：研究不同长度支抗种植体对骨界面应力分布的影响，以供临床筛选合适的种植体。方法：用三维有限元方法给种植体施加150g近远中方向的载荷，分别对长度为7mm、10mm、15mm的支抗种植体-骨界面进行应力分析。结果：三种长度种植体颈部的Von-Mises应力值分别为0．5450MPa、0．5330MPa、0．5320MPa；位移值分别为0．1690μm、0．1630μm、0．1610μm。结论：在种植体承受侧向力载荷时，增加种植体长度可提高其承载能力，临床上在选择正畸支抗种植体时，应尽量选择长种植体作正畸支抗体。     

骨涎蛋白在不同类型种植体骨界面改建中的变化

目的:比较埋植型与非埋植型种植体在义齿修复受载后,种植体-骨界面中骨涎蛋白表达的变化。方法:选用纯系Beagle犬8只,在其下颌左右两侧分别植入埋植型与非埋植型种植体各3枚,每侧第一枚不作义齿修复,用于对照,其余各枚均采用固定金属全冠行种植义齿修复,分别于修复后2、4、8、12周各处死2只动物,取下颌骨相应骨段,于每个种植体周围10 mm处制作颊舌向纵行石蜡切片(片厚4μm),采用免疫组化染色方法检测种植体-骨界面骨涎蛋白表达情况。结果:两对照组(未修复组)种植体-骨界面组织中骨涎蛋白均呈弱阳性表达,且各时间点表达均无明显差异(P>0.05)。而两实验组(修复受载后)种植体-骨界面组织中骨涎蛋白表达的阳性强度均随观察时间延长而增加,8周时达高峰,12周时出现回落;同一时间点内埋植型与非埋植型种植体相比,无论是对照组还是实验组,各时间点内的骨涎蛋白表达程度均无显著性差异(P>0.05)。结论:埋植型和非埋植型种植体在义齿修复受载后,所承受的机械负荷均能刺激种植体-骨界面骨涎蛋白表达发生规律性变化,促进其界面的改建;且埋植型和非埋植型种植义齿受载后其界面的改建之间无显著性差异(P>0.05)。     

埋植型与非埋植型种植体周围骨改建的扫描电镜观察

目的 :观察埋植型与非埋植型种植体受载后周围骨改建的超微结构变化。方法 :选用纯系动物Beagle犬 8只 ,在其下颌分别植入埋植型与非埋植型种植体 ,采用金属全冠修复。不同时期取带种植体的骨标本制备超硬切片 ,扫描电镜观察。结果 :未受载的种植体与骨组织之间呈直接的骨接触 ;加载 2周后 ,种植体与骨组织界面绝大部分呈直接骨结合 ,在界面骨组织侧出现暗影 ;加载 4周后 ,界面骨组织侧暗影明显减少 ;加载 8周和 12周后种植体与骨组织直接接触 ,界面骨组织侧无明显暗影。各时期埋植型和非埋植型种植体骨组织界面超微结构无明显区别。结论 :受载后种植体 -骨组织界面的改建存在一个动态变化过程 ,埋植型与非埋植型种植体对界面超微结构无明显影响。     

The impact of nicotine on bone healing and osseointegration

OBJECTIVES: To examine the short-term effect of nicotine on bone healing and osseointegration. MATERIAL AND METHODS: Sixteen female rabbits were divided into two groups. The test group was exposed to nicotine tartrate for 8 weeks and the control group was exposed to placebo. Nicotine or placebo was administered via a miniosmotic pump and plasma cotinine levels were measured weekly. The pump delivered 15 mg of nicotine/day for the animals in the test group. All rabbits had three tibial bone preparations. In the proximal and distal bone bed, implants were placed after 4 weeks (right tibia) and after 6 weeks (left tibia). Thus, 2- and 4-week healing groups were created. Removal torque test (RMT) was performed at the distal implants. Ground sections were made from the proximal and the central bone beds. The fraction of mineralized bone in contact to the implant (BIC) and the bone density within the implant threads (BD-i) were determined for the bone-implant specimens. For the central bone beds without implants the bone density (BD-c) in the bone defects was determined. RESULTS: No significant difference in RMT values was found between the test and the control group. Histomorphometric measurements of the BIC and the peri-implant BD-i showed no significant differences between the test and the control group after 2 or 4 weeks. Significant differences were, however, found between the 2- and 4-week samples. In the central bone beds, there was no significant difference in BD-c between the test and the control group. CONCLUSION: Nicotine exposure in a short period of time did not have a significant impact on bone healing or implant osseointegration in rabbits.