铸道设计对贵金属烤瓷合金铸态组织影响的实验研究

目的 研究不同的铸道设计形式对贵金属烤瓷合金铸态组织的影响，为该类合金的临床规范化应用提供理论依据。方法 应用倒置式金相显微镜观察BioHeradorN金烤合金不同铸道设计形式下的铸态组织，通过观察铸件中缩孔缩松产生的数量和分布比较铸道设计形式（树型、环型、环型）对铸件的影响程度。结果 铸道设计形式对合金铸态组织有明显影响，随铸道设计形式不同缩孔缩松产生的数量及分布有异。除环型铸道设计外，其它形式的铸道设计会使铸件中产生明显的铸造缺陷，即缩孔缩松的数量分布增多增广。结论 BioHeradorN金烤瓷合金铸态组织以环型铸道设计组织最为致密，常见缩孔缩松缺陷不易产生。     

异种烧结骨修复颌骨缺损的临床观察

本文报告了应用异种烧结骨修复颌骨缺损25例,采用手术前后X线及免疫学、r骨显像等观察,进行了较系统的临床研究.经6～12个月追踪观察,结果表明:创口愈合正常,未见免疫排斥反应.术后3周左右植骨成活,2～3个月有新骨形成、与空白对照组比较,烧结骨有明显加快骨缺损部位成骨作用,新生骨出现早,成骨速度快.证实烧结骨具有良好的组织相容性和骨传导能力,具有较高的临床实用性,是一种较理想的骨移植材料.     

Postoperative exposure of bioresorbable GTR membranes: effect on healing results

The goal of this investigation was to evaluate the effect of postoperative exposure of two different bioresorbable membranes on the guided tissue regeneration (GTR) healing results compared to nonexposed sites. In each of 25 patients one pair of contralateral intrabony lesions was treated either with polylactic acid (PLA) or polyglactin 910 (PG-910) membranes. Postoperative exposure occurred in 9 PLA and 13 PG-910 sites. Standardized clinical [papillary bleeding index (PBI), gingival recession (REC), probing pocket depth (PPD), probing attachment level (PAL)] and radiographic examinations (digital subtraction radiography) were performed immediately before (baseline) and 6 and 12 months postoperatively (p.o.). Subgingival bacterial samples from surgical sites were evaluated by culture at baseline, 6 weeks, and 6 and 12 months p.o. Six months after surgery the changes (Δ) of REC were significantly (P≤0.05) greater in exposed than in nonexposed sites, independently of the membrane material (median): exposed sites, ΔREC=–1 mm; nonexposed sites, ΔREC=0.0 mm. However, 12 months p.o. no significant differences were found due to a decrease in the initial recessions in exposed sites. Although a higher percentage of exposed than nonexposed sites harbored periodontal pathogens 6 weeks p.o. at the gingiva-faced membrane surface, membrane exposure did not have a significant negative effect on ΔPPD, ΔPAL, or radiographic bone density changes 6 and 12 months p.o. Both membranes showed significant gains in PAL and bone density in both exposed and nonexposed sites. In conclusion, this study demonstrates that with consistent infection control the postoperative exposure of PLA and PG-910 membranes has no significant negative effect on the regeneration outcome, although higher initial gingival recessions must be expected than in the nonexposed sites. However, in exposed sites plaque and infection control were clearly impeded by the rough, exposed membrane surfaces and by the initially negative gingival morphology. Received: 22 January 1997 / Accepted: 5 May 1997     

楔状缺损与咬合力关系的研究

目的 临床研究楔状缺损与He力的关系。方法 将123例患不同程度楔状缺损的中老年患者，按楔状缺损的程度分为无、轻、中、重度4组；使用电阻应变式咬合力计测量上颌尖牙、第一、二双尖牙、第一磨牙牙齿咬合力；用光He法测定上颌牙齿最高He接触强度。结果 楔状缺损患牙的咬合力低于无楔状缺损牙。上颌第一双尖牙的楔状缺损患牙的最高He接触强度高于未患牙、楔状缺损组中的第一磨牙和第一双澡牙相对于其邻牙的最高He接触强度增高。结论 He力与楔状缺损的发生有关。     

Reliability of assessing interproximal bone loss by digital radiography: intrabony defects

AIM: The aim of the present study was to assess the reproducibility and validity of linear measurements of interproximal bone loss in intrabony defects on digitized radiographic images after application of different filters and magnifications. METHODS: Immediately before surgery 50 radiographs of 50 periodontally diseased teeth exhibiting interproximal intrabony defects were obtained by a standardized technique in 50 patients. Intrasurgically the distances from the cementoenamel-junction (CEJ) to the alveolar crest (AC) and from the CEJ to the deepest extension of the bony defect (BD) were assessed. All radiographs were digitized by a flatbed scanner (resolution: 600x1200 dpi). Using the FRIACOM-soft ware, the linear distances CEJ to AC and CEJ to BD were measured at 50 intrabony defects on digitized but unchanged radiographic images and also after use of 2 different basic image processing modes (filters: enhancement of grey level differences, spreading of grey values) with 7-fold and 14-fold magnification by 2 different examiners. RESULTS: Repeated measures MANOVA revealed reproducibility of the measurement of the distance CEJ to AC to be significantly influenced by examiner (p=0.027) and filter in combination with the height of 2 wall component of the intrabony defect (p=0.066). For the distance CEJ to BD filters had significant influence on reproducibility in correlation with vertical angulation difference (p=0.001). On the average in this study radiographic measurements tended to overestimate the amount of bone loss as assessed by intrasurgical measurements (CEJ-AC: 0.74-1.91 mm; CEJ-DB: -0.04-0.77 mm). Validity of measurement of the distance CEJ-AC was shown to be significantly influenced by the depth of the intrabony defect (p<0.003). Validity of the distance CEJ-BD was significantly influenced by intrasurgically assessed bone loss (p=0.029), horizontal angulation (p=0.066). Filters influenced the validity only in combination with examiner (p<0.001). CONCLUSIONS: In this study, the chosen digital manipulations (filters: spreading, structure) of radiographic images failed to result in statistically significantly more reproducible or valid measurements of interproximal bone loss within intrabony defects when compared to the digitized but unchanged images. All radiographic assessments on the digitized images except for use of enhancement of grey level differences (structure) came close to the intrasurgical gold standard.     

异种脱细胞真皮基质修复膜在口腔黏膜下纤维性变手术治疗中的应用

目的:评价异种脱细胞真皮基质修复膜在口腔黏膜下纤维性变手术治疗中的应用效果。方法:8例重度口腔黏膜下纤维性变患者,经鼻腔气管插管全麻下切除双侧颊部翼下颌韧带前方区域纵行的纤维条索,术中被动开口度达正常范围后,剪取相应大小的异种脱细胞真皮基质修复膜覆盖黏膜缺损创面,间断缝合后,碘纺纱包加压固定。术后10～14d拆除纱包与缝线后开始开口训练,定期随访并进行类固醇皮质激素黏膜下局部注射等辅助治疗,通过伤口愈合、瘢痕软化及开口度改善等指标评价手术效果。采用SPSS16.0软件包对数据进行单因素方差分析。结果:8例患者双侧颊部纤维条索切除后形成的手术创面,采用异种脱细胞真皮基质修复膜进行修复均获得成功,无感染或排异等并发症发生。术后随访6～18个月,患者颊部原手术区黏膜红润,质地柔软,开口困难明显改善。术前开口度为(12.04±2.93)mm,术中开口度为(35.46±3.17)mm,术后6个月时的开口度为(29.33±4.28)mm,经统计学分析,差异具有显著性(P<0.05)。结论:应用异种脱细胞真皮基质修复膜修复重度口腔黏膜下纤维性变手术治疗中的黏膜缺损创面,能够起到促进创面早期愈合、减轻瘢痕形成与改善开口困难的作用,其操作简单易行,值得临床推广应用。     

EIS study of solid-state transformations in the passivation process of bismuth in sulfide solution

Anodic oxidation of polycrystalline bismuth in alkaline medium, containing sulfide ions was investigated in situ. Cyclic voltammetry was used to define the potential regions of formation and stability of anodic Bi₂S₃ and Bi₂O₃ semiconductor films that translate bismuth to the passive state. The mechanism of elementary steps of the passivation process has been investigated using electrochemical impedance spectroscopy (EIS). The electric and dielectric properties of anodic films and structural parameters of the interfaces Bi–growing film–electrolyte in a wide region of potentials and frequencies of six decades, were determined. The EIS data have been analyzed and discussed in the frame of the point defect model (PDM) of anodic film formation and growth. The growth of passive surface films on bismuth takes place via transport of anionic vacancies generated at the metal–film interface. The slow step of the process is the layer-limited diffusion of anionic vacancies (D≈ 10^?16 cm² s^?1).Solid-state transformation of sulfide to the oxide film is a consequence of OH^? ion capture into the anionic vacancies of the sulfide film, the generation and transport of cation vacancies from the film–solution interface, their annihilation and formation of a vacancy condensate of a critical size at the metal–film interface.     

磷酸钙骨水泥与骨形成蛋白复合修复即刻种植牙骨缺损的实验研究

目的：探讨磷酸钙骨水泥(CPC)与人重组骨形成蛋白-2(rhBMP-2)复合修复即刻种植牙骨缺损的效果，为其临床应用于种植牙骨缺损修复的可行性奠定理论基础。方法：在兔股骨大转子上模拟即刻种植模型，种植体周围骨缺损区植入CPC／rhBMP-2及CPC进行修复，通过X线片，骨密度测量及组织学检查，观察新骨形成情况和材料的微观结构变化以及新骨与种植体的关系。结果：CPC／-rhBMP-2复合物可以有效地修复即刻种植牙骨缺损，材料被逐渐降解吸收，新骨与种植体表面更早地结合。结论：CPC／rhBMP-2是一种比较理想的新型骨移植材料.     

Guided tissue regeneration in conjunction with hydroxyapatite-collagen grafts for intrabony defects

Abstract This clinical and radiological study evaluated the healing of 3 + 2 + 1 wall-combined intrabony defects treated using the guided tissue regeneration technique (GTR) with and without hydroxyapatite-collagen alloplastic graft materials (HAC), in comparison to that of HAC alone and conventional flap surgery (CF), 40 interproximal defects with probing depth >6 mm were treated in 18 adult periodontitis patients of ages 35–60 years. After non-surgical therapy, the defects were randomly grouped into 4 groups of 10 defects each. These groups were designated: (1) expanded polytetrafluoroethylene membrane (e-PTFE), (2) e-PTFE+HAC. (3) HAC alone and (4) CF. At 6 months, the following changes in parameters were recorded. Mean PPD reduction for each group was 5.83, 5.85, 3.80 and 3.17 mm respectively. PPD reduced very significantly in all groups (P<0.01), the highest and lowest reductions in PPD being for the e-PTFE + HAC and CF group respectively. Comparison between the 4 groups showed higher PPD reduction in both membrane groups than in either of the non membrane groups (p<0.05) with the difference between the e-PTFE and CF groups being very highly significant (p<0.001). Mean attachment gain for the 4 groups was 3.70. 3.80. 2.60 and 2.1 mm, respectively. Similarly attachment gain for all groups was very significant (p<0.01) and the highest and lowest attachment gains were for the e-PTFE+HAC and CF group respectively. Both membrane groups showed significantly more attachment gain than the CF group (p<0.05). Change in probing bone level (BL) for the 4 groups was 1.60. 1.90. 1.0 and 0.65 mm respectively. Again the highest changes in BL were recorded for the e-PTFE + HAC group. Significant differences were found between both membrane groups and the CF group (p<0.05). Radiological evaluation using standardized radiographs and millimeter grids showed change in radiographic bone level at the deepest point of the defect on the radiograph to be 1.50, 1.55, 0.85 and 0.60 mm, respectively and this was significantly higher in both membrane groups than in the CF group (p<0.05). This study therefore found e-PTFE membranes both alone and when combined with HAC to lead to more attachment gain and bone fill than did HAC alone or CF. It found HAC combined with e-PTFE to perform better although not significantly better than e-PTFE alone.     

Oral anomalies in Nigerian children

A total of 2203 Nigerian school-age children (10-19 yr) were examined clinically for the presence of oral anomalies. The following prevalence figures were found: commissural lip pits (2.9%), ankyloglossia (0.2%), geographic tongue (0.3%), fissured tongue (0.8%), torus palatinus (4.5%), torus mandibularis (1.9%), snowcap type amelogenesis imperfecta (0.2%), localized enamel hypomaturation (11.7%), missing lateral incisors (0.7%), and peg lateral incisors (1.5%). None of the following conditions was found: cleft chin, cleft lip, double lip, medium rhomboid glossitis, bifid tongue, macroglossia, cleft palate or cleft lip and palate.