Ex Vivo Detection of Apical Delta in Premolars: A Comparative Study Using Periapical Radiography,Cone-beam Computed Tomography,and Micro–computed Tomography

Introduction

Imaging methods are essential for the correct identification of root canal anatomy, which is a key factor for successful endodontic therapy. This study aimed to evaluate the performance of periapical radiography (PR) and cone-beam computed tomographic (CBCT) imaging in identifying the apical delta (AD) using micro-computed tomographic imaging as the gold standard.

Brain activation patterns during unilateral premolar occlusion

Objective: To observe the characteristics of brain activation during unilateral premolar occlusion.

Methods: Functional magnetic resonance imaging was collected from 10 healthy volunteers during occlusion of the left first premolar (L1), left second premolar (L2), and right first premolar (R1). The brain activation patterns were analyzed, and the primary sensorimotor cortex, supplementary motor area, insula, thalamus, and prefrontal cortex were chosen as regions of interest.

Results: Single premolar occlusion activated the precentral gyrus, postcentral gyrus, cerebellum, thalamus, frontal lobe, hippocampus, cingulate gyrus, and parietal lobe. The brain areas showing activation during single premolar occlusion were similar to those activated by chewing. The activation pattern of L1 was more similar to that of L2 than R1. No significant left and right hemisphere differences in signal intensity were detected within the regions of interest.

Conclusion: Brain activation patterns from two ipsilateral premolars were more similar than the pattern from a contralateral premolar.     

冷冻异体硬脑膜引导骨组织再生在口腔种植中的临床应用

采用异体硬脑经膜冷冻处理，作为引导种植体周围骨组织再生的膜材料，经临床24例应用观察，未发生伤口愈合不良、形成瘘道等现象，所有病例种植体稳固，骨再生修复良好。其中15例（16区）裂隙状骨缺报引导骨组织修复率达87．8％。临床应用表明，冷冻异体硬脑膜引导骨组织再生，具有来源广、制备贮存简便，不产生排斥反应，引导骨组织生长效果好等特点，是目前较理想的引导骨组织再生膜材料、可广泛应用于各类与种植有关的骨缺损。还讨论了与提高引导骨组织再生效果有关的手术技巧。     

A clinical evaluation of a bioresorbable barrier with and without decalcified freeze-dried bone allograft in the treatment of molar furcations

Abstract This study evaluated a bioresorbable barrier with and without decalcified freeze-dried bone allograft (DFDBA) in the treatment of human molar furcations. 14 subjects with paired class II mandibular molar furcation defects participated in the study (8 male and 6 female). The class-II furcation defects were randomly treated with either the resorbable barrier alone or resorbable barrier in combination with decalcified freeze-dried bone allograft (DFDBA). Gingival recession, probing depth, clinical attachment, and bone fill were measured. 6 months post-treatment measurements were repeated and each site was surgically re-entered. When the resorbable barrier alone was compared to resorbable barrier in combination with DFDBA. probing depth reduction was significantly (p<0.01) in favor of the combination therapy. Vertical bone gain was significant with the combination treatment demonstrating more bone fill (p<0.02). Smoking was also a variable examined in this study. When compared to smokers, non-smokers for both treatment groups revealed greater probing depth reduction, vertical bone gain, and horizontal bone gain. Within the non-smoking group, probing depth reduction was also significantly higher for the resorbable barrier and DFDBA group than the resorbable alone group (p<0.02). These results illustrate that the probing depth reduction is better in the non-smoker and the best in the non-smoker with the combination therapy of resorbable barrier and DFDBA than with resorbable barrier alone.     

Immediate implant placement with transmucosal healing in areas of aesthetic priority. A multicentre randomized-controlled clinical trial I. Surgical outcomes

OBJECTIVES: To compare the clinical outcomes of standard, cylindrical, screw-shaped to novel tapered, transmucosal (Straumann Dental implants immediately placed into extraction sockets. Material and methods: In this randomized-controlled clinical trial, outcomes were evaluated over a 3-year observation period. This report deals with the need for bone augmentation, healing events, implant stability and patient-centred outcomes up to 3 months only. Nine centres contributed a total of 208 immediate implant placements. All surgical and post-surgical procedures and the evaluation parameters were discussed with representatives of all centres during a calibration meeting. Following careful luxation of the designated tooth, allocation of the devices was randomly performed by a central study registrar. The allocated SLA titanium implant was installed at the bottom or in the palatal wall of the extraction socket until primary stability was reached. If the extraction socket was >or=1 mm larger than the implant, guided bone regeneration was performed simultaneously (Bio Oss and BioGide. The flaps were then sutured. During non-submerged transmucosal healing, everything was done to prevent infection. At surgery, the need for augmentation and the degree of wound closure was verified. Implant stability was assessed clinically and by means of resonance frequency analysis (RFA) at surgery and after 3 months. Wound healing was evaluated after 1, 2, 6 and 12 weeks post-operatively. RESULTS: The demographic data did not show any differences between the patients receiving either standard cylindrical or tapered implants. All implants yielded uneventful healing with 15% wound dehiscences after 1 week. After 2 weeks, 93%, after 6 weeks 96%, and after 12 weeks 100% of the flaps were closed. Ninety percent of both implant designs required bone augmentation. Immediately after implantation, RFA values were 55.8 and 56.7 and at 3 months 59.4 and 61.1 for cylindrical and tapered implants, respectively. Patient-centred outcomes did not differ between the two implant designs. However, a clear preference of the surgeon's perception for the appropriateness of the novel-tapered implant was evident. CONCLUSIONS: This RCT has demonstrated that tapered or standard cylindrical implants yielded clinically equivalent short-term outcomes after immediate implant placement into the extraction socket.     

Periodontal repair in dogs: evaluation of a bioresorbable calcium phosphate cement (Ceredex) as a carrier for rhBMP-2

BACKGROUND: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been shown to induce clinically relevant bone formation for orthopedic, craniofacial, and oral indications. It appears critical, in particular for onlay indications, that the associated carrier technology exhibits structural integrity to offset compressive forces in support of rhBMP-2-induced bone formation. The objective of this study was to evaluate a calcium phosphate (CP) cement, Ceredex, as a candidate carrier for rhBMP-2 in a defect model with limited osteogenic potential. MATERIALS: Bilateral, critical size, 6-mm, supra-alveolar, periodontal defects were created in six, adult, male, Hound Labrador mongrels. Three animals received rhBMP-2/Ceredex (rhBMP-2 at 0.20 and 0.40 mg/ml) in contralateral defect sites (implant volume/defect approximately 1 ml). One defect site in each of the three remaining animals received Ceredex without rhBMP-2 (control). The animals were euthanized at 12 weeks postsurgery for histologic and histometric analysis. RESULTS: Mean induced bone height exceeded 80% of the defect height for supra-alveolar periodontal defects receiving rhBMP-2/Ceredex without major differences between rhBMP-2 concentrations compared with approximately 40% for the control. The newly formed bone, a mixture of lamellar and woven bone in fibrovascular tissue, circumscribed relatively large portions of the residual Ceredex biomaterial. Inflammatory lesions were associated with limited bone formation in some sites. From a periodontal perspective, sites receiving rhBMP-2/Ceredex exhibited increased cementum formation compared with control, but without a functionally oriented periodontal ligament, and increased ankylosis and root resorption. Control sites exhibited early wound failure and exposure, loss of the Ceredex biomaterial, and limited bone formation. CONCLUSIONS: The Ceredex CP cement appears a potentially promising carrier technology for rhBMP-2 onlay indications. However, a slow resorption rate may prevent its wider use. This study does not support use of the rhBMP-2/Ceredex combination for periodontal indications.     

Contemporary management of lateral root perforation diagnosed with the aid of dental computed tomography

Lateral root perforation unnoticed during post-space preparation, and followed by post cementation, can subsequently be challenging to diagnose in the labio-lingual plane due to the two-dimensional nature of conventional radiography. This paper demonstrates the application of a recently developed three-dimensional imaging system, cone beam computed tomography, in the diagnosis of iatrogenic root perforation. A clinical case is reported where labial post perforation in a maxillary central incisor occurring 15 years previously presented with a sinus tract and radiolucent lesion. Non-surgical retreatment and perforation repair using mineral trioxide aggregate was performed with the aid of an operating microscope. The sinus tract resolved with radiographic evidence of healing at 1-year recall.     

人釉原蛋白真核表达载体体外表达产物生物学活性的检测

目的探讨人釉原蛋白基因重组质粒PcDNA3．1-AMG的真核细胞转染表达产物是否具有促进牙周组织再生的作用。方法脂质体介导PcDNA3．1-AMG体外转染COS1细胞．ELISA法检测转染细胞内及其培养上清液中重组釉原蛋白的表达：建立犬牙周组织缺损模型．局部使用转染表达产物冻干粉．8周后通过组织学观察牙周组织再生的情况。结果PcDNA3．1-AMG转染的COS1细胞内重组釉原蛋白浓度为（0．253±0．075）μg／ml。培养液中浓度为（0．065±0．011）μg／ml；使用转染表达产物8周后．牙周缺损区牙骨质、牙槽骨均有显著再生，并且新生牙骨质为有胶原纤维穿通的无细胞牙骨质。结论重组质粒PcDNA3．1－AMG在体外转染哺乳动物细胞后能够表达重组人釉原蛋白．并且表达产物具有促进牙周组织再生的生物学活性。     

基质金属蛋白酶在牙本质龋中的作用

基质金属蛋白酶(MMPs)是一类蛋白水解酶,在体内可水解细胞外基质成分。在牙本质龋发生的过程中,致龋菌释放的酸使pH值下降,来自于唾液和牙本质的MMPs被激活,当唾液缓冲系统使pH值恢复中性后,MMPs可水解脱矿的牙本质。基质金属蛋白酶抑制剂如MMPs组织特异性抑制剂及从天然来源的物质中提取出的某些成分可有效抑制MMPs活性。本文就MMPs生物学特性、在牙本质龋中的作用以及其抑制剂的研究进展作一综述。     

36例良、恶性淋巴上皮病临床病理分析

目的：分析恶性淋巴上皮病（MLEL）、良性淋巴上皮病（BLEL）及与之相联系的黏膜相关淋巴组织型结外边缘区B细胞淋巴瘤（MALToma）的临床特点、病理学特征、发病机制、诊断、治疗及转归。方法：对13例MLEL、20例BLEL及3例MT进行免疫组化染色和HE染色观察，复习相关临床资料并随访。结果：MLEL的病理学特征为大量增生的淋巴组织中见成簇或条索状分布的肿瘤细胞，界限不清，核分裂像多见；免疫组化示CKpan全部阳性（13／13），Vim部分阳性（3／13），SMA部分阳性（2／13）；8例MLEL可随访资料中，术后1例死于复发，1例死于其他疾病，1例局部复发，5例未见复发或转移，随访3．5个月-4a。BLEL的病理学特点为腺实质萎缩，间质淋巴细胞浸润及形态温和的腺肌上皮岛；免疫组化示CKpan19例阳性，LCA17例阳性。UCHL-1、L2616例阳性。CK10 10例阳性．S-1002例阳性；12例可随访的BIEL中，2例术后复发诊断为MLEL，其余健在，随访3个月～6a不等。3例MT中。1例术后6个月复发，经再次手术并化疗后缓解；免疫组化L26、LCA、CD79、CD43均阳性；UCHL-1、CKpan、EMA均有2例阳性。结论：MLEL好发于腮腺，且女性多见，来源于唾液腺导管上皮。对已发生颈淋巴结转移的患者行原发灶一颈联合根治，术后放疗，少数MLEL可在BLEL基础上发生，故BLEL局部切除后应长期随访；MT为B细胞淋巴瘤，手术切除辅以适当化疗可获较好疗效。术中冷冻切片是本病目前最可靠的术中诊断手段。