Clinical evaluation of ceramic inlay made by CAD/CAM for 3 year]

In this study,ceramic inlays made by CAD/CAM system were used to restore posterior tooth defects.After three years of clinical observation on 21 prostheses no secondary caries was found and patients satisfied with their restoration on aspects of color match and resistance to wear etc.Five cases of inlay fracture and of obvious space between inlay margin and Cavowall were found.The main reason was the insufficient thickness of the inlays meanwhile the selection of bonding agent was not appropriate.The clinical successful rate is 76.20%.As CAD/CAM is a sophisticated technique induced into prosthodontic area just in 1980's,it has still some deficiency to be improved and perfected.     

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。     

福建省唇腭裂年度及地区发病率的研究

根据福建省22所医院自1986年10月至1992年12月6年间住院分娩的资料整理。在139882名新生儿中有唇腭裂患儿104例，其中单纯唇裂61例，单纯腭裂28例，，唇裂伴腭裂115例，福建省唇腭裂发病率为1．46‰。作者进一步对六年度发病率及发地区的发病率进行了探讨，结果福建省六年的年平均发病率为1．50‰，但发病率与年份变化无显著意义。福建省沿海及非沿海地带的发病率无显著差别，但九地区的地区发病率则有差别，最高为2．06‰，最低为0．69‰。     

Quantitative study of velopharyngeal function post-palatoplasty]

The computer of nasopharyngeal fiberscope(NPF) for quantitative analysis was carried out to assess the palate articulation of 43 subjects,and normal articulation of 60 subjects.The rest,/a/,/s/and /m/ articulation of NPF pictures were calculated for veloparyngreal function via computer.     

Education of dentists in China

China is geographically located in the east of Asia and its population exceeds 1.3 billion. An understanding of dental education in China is thus of interest. However, as there is little published information on this topic, this paper provides information about China regarding its dental history, dental school system including curriculum and dental licensure. High school graduates take a nationwide entrance examination to apply for dental school, of which there are more than 50 in China. A five year dental education leads to the BDS degree. Dental school graduates must then pass the nationwide licensure examination to practise dentistry. Currently, there are not adequate numbers of dentists to provide the necessary oral health care for people living outside metropolitan areas.     

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.     

Resazurin metabolism assay for root canal disinfectant evaluation on dual-species biofilms

Introduction

Endodontic infections are caused by polymicrobial biofilms. Therefore, novel root canal disinfectants should be evaluated not only on single-species biofilms but also on dual- or mixed-species biofilms. A simple, high-throughput assay is urgently needed for this. In this study, the application of the resazurin metabolism assay was investigated for the evaluation of a root canal disinfectant on dual-species biofilms.

Methods

Enterococcus faecalis with or without Streptococcus mutans in biofilms were formed in an active attachment biofilm model for 24 hours. Subsequently, the biofilms were treated with various concentrations of NaOCl for 1 minute. After resazurin metabolism by both organisms was confirmed, treatment efficacies using 0.0016% resazurin were evaluated.

Results

During NaOCl treatments, resazurin metabolism displays a clear dose response, not only in single-species E. faecalis (or S. mutans) biofilms but also in dual-species biofilms. Notably, the assay revealed that the resistance of dual-species biofilms to NaOCl was 30-fold higher than in single-species E. faecalis biofilms. Viability counts on a selected NaOCl treatment (0.004%) confirmed this result and showed the increased resistance of E. faecalis in dual-species biofilms.

Conclusions

Clearly, the high-throughput and low cost resazurin metabolism assay has a great potential for testing novel root canal antimicrobial agents in mixed-species biofilms.     

胶囊粉对可见光固化复合树脂机械性能的影响

目的:改善光固化复合树脂的强度和抛光性能.方法:我们采用悬浮聚合法研制了微胶囊型复合填料粉(MCP),作为光固化改进型(VLC-Ⅱ型)复合树脂的填料.并对其性能进行了测试.结果:在复合树脂中加入15%的胶囊型填料粉,压缩强度可达232.1±9.1MPa,拉伸强度可达48.7±2.3MPa,70000次牙刷磨耗率为0.588%,表面粗糙度为2.8μm.结论:胶囊粉可以显著改善复合树脂的压缩强度,拉伸强度,磨耗及表面抛光性等机械性能.与其它同类产品比较,其机械性能、磨耗性能和表面抛光性能均较优越,且相差显著.     

Effect of desensitising toothpastes on dentinal tubule occlusion: A dentine permeability measurement and SEM in vitro study

Objectives

The purpose of this study was to evaluate the in vitro effectiveness of a new bioglass-containing and two commercial desensitising toothpastes on dentinal tubule occlusion after citric acid challenge or artificial saliva (AS) immersion.

Methods

One hundred dentin discs from human third molars were used. Specimens were randomly divided into five groups (n = 20), Group 1: EDTA-treated dentin; Group 2: brushing with distilled water; Group 3: brushing with Novamin; Group 4: brushing with Sensodyne Freshmint; Group 5: brushing with Colgate Sensitive. In each group, samples were then equally split into two subgroups (n = 10) to test two post-treatments: 6% citric acid challenge or 24 h immersion in artificial saliva. Dentine permeability of each specimen was measured before and after each treatment using a hydrostatic device working at 20 cm H₂O pressure. Data were analysed by two-way repeated measures ANOVA to determine if there were any significant differences within or between groups. Dentine morphology and surface deposits were observed by SEM.

Results

All three desensitising toothpastes significantly reduced dentine permeability and created precipitates on the treated dentine surfaces. Moreover, the reductions in dentine permeability showed partial recovery after a citric acid and artificial saliva immersion. Sensodyne showed significant resistant to acid attack and Novamin exhibited the lowest permeability after artificial saliva immersion for 24 h.

Conclusions

The application of the three toothpastes resulted in effective dentinal tubule occlusion. However, the new bioglass-containing toothpaste (Novamin) represented excellent occlusion effects after brushing treatment and AS immersion, while Sensodyne demonstrated more reduction in permeability when citric acid challenged.