长春地区儿童乳牙急慢性根尖周炎根管内厌氧菌的分析

目的 对长春地区60例儿童急慢性根尖周炎患者的感染根管进行厌氧菌分离鉴定，为指导临床选择用药奠定基础。方法 利用智能化细菌鉴定和药敏系统-ATB快速鉴定仪分离培养和鉴定细菌。结果 98．3％（59／60）的患牙共检出厌氧菌144株，平均每例标本检出2．44株。结论 乳牙急性根尖周炎感染根管内的优势菌以梭杆菌为主，慢性根尖周炎感染根管内的优势菌以放线菌为主。     

Histological periapical repair after obturation of infected root canals in dogs.

Histological periapical healing of infected roots obturated in one-step or with prior calcium hydroxide (Ca(OH)2) disinfection was compared. Seventy-two roots of vital dog teeth were instrumented to ISO size 45. Sixty roots were infected with dental plaque and closed. Six weeks later, apical periodontitis was radiographically confirmed in the infected roots. The teeth were divided into the following groups: group 1, one-step (n = 24)-roots were irrigated with 10 ml of saline, obturated, and permanently restored; group 2, Ca(OH)2 (n = 24)-roots were treated as in group 1, except that after saline irrigation, Ca(OH)2 dressing was placed in the canal for 1 wk before obturation; group 3, positive control (n = 12)--the roots were irrigated with saline, but the canals were not obturated; and an additional group, group 4, served as a negative control (n = 12)--these teeth that were not infected with plaque were aseptically obturated. The dogs were sacrificed after 6 months. The roots and surrounding apical tissues were prepared and histologically examined by two independent evaluators blinded to the treatment groups. A two-way ANOVA test demonstrated that the four treatment groups were significantly different from one another. The positive control showed the most inflammation, the negative control the least, and the Ca(OH)2 group had significantly less inflammation than the one-step group (p < 0.05). It is concluded that Ca(OH)2 disinfection before obturation of infected root canals results in significantly less periapical inflammation than obturation alone.     

不同根管充填技术对椭圆形根管充填效果的比较

目的:通过比较3种不同方法充填椭圆形根管后的牙胶充填面积百分数来评价各种充填法的效果。方法:选取人离体单根管前磨牙30个,手用ProTaper预备后随机分为3组,分别用冷牙胶侧方加压法、热塑牙胶注射加压法(ObturaⅢ)和连续波充填法(System B+ObturaⅢ)进行充填,然后分别在距根尖2、5、8 mm处横断,各个横断面在手术显微镜下拍照,再用图像分析软件记录横断面的根管面积和牙胶充填面积,从而计算出牙胶充填面积百分数。结果:在2 mm处,3种充填法的牙胶充填面积百分数无显著性差异(P>0.05);在5 mm处,ObturaⅢ组和SystemB+ObturaⅢ组无显著性差异(P>0.05),但都显著大于冷牙胶侧压组(P<0.05),8 mm与5 mm处结果相同。结论:在5,8 mm水平,ObturaⅢ和SystemB+ObturaⅢ充填法的效果好于冷牙胶侧压法,而在2 mm水平,3种充填法的的效果无明显差别。     

Antimicrobial susceptibility of Enterococcus faecalis isolated from canals of root filled teeth with periapical lesions

AIM: To test, in vitro, the susceptibility to different antibiotics of Enterococcus faecalis isolates from canals of root filled teeth with periapical lesions. METHODOLOGY: Twenty-one E. faecalis isolates, from canals of root filled teeth with persisting periapical lesions, were tested for their antibiotic susceptibilities. The following antibiotics were used: benzylpenicillin, amoxicillin, amoxicillin-clavulanic acid, erythromycin, azithromycin, vancomycin, chloramphenicol, tetracycline, doxycycline, ciprofloxacin and moxifloxacin. Minimal inhibitory concentrations (MICs) for the antimicrobial agents were determined using the E-test System (AB BIODISK, Solna, Sweden), and the E. faecalis strains classified as susceptible or resistant according to the guidelines of National Committee for Clinical Laboratory Standards (NCCLS). The strains were also tested for beta-lactamase production with nitrocefin (Oxoid, Basingstoke, UK). RESULTS: All strains were susceptible to penicillins in vitro, however, the MICs of amoxicillin and amoxicillin-clavulanic acid (MIC(90) = 0.75 microg mL(-1)) were lower than for benzylpenicillin (MIC(90) = 3.0 microg mL(-1)). All strains studied were also susceptible to vancomycin and moxifloxacin, whilst 95.2% were susceptible to chloramphenicol. Amongst the isolates, 85.7% were susceptible to tetracycline and doxycycline and 80.9% to ciprofloxacin. The MIC of erythromycin ranged from 0.38 to >256 microg mL(-1); only 28.5% of the strains were susceptible (MIC < or = 0.5 microg mL(-1)). Limited susceptibility was also observed with azithromycin which was active against only 14.2% of isolates. No strains produced beta-lactamase. CONCLUSION: Enterococcus faecalis isolates were completely susceptible, in vitro, to amoxicillin, amoxicillin-clavulanic acid, vancomycin and moxifloxacin. Most isolates were susceptible to chloramphenicol, tetracycline, doxycycline or ciprofloxacin. Erythromycin and azithromycin were least effective.     

锥形束CT与根尖X线片对牙根纵裂诊断价值的对比研究

目的:对比研究牙科锥形束CT(CBCT)与普通根尖X线片在牙根纵裂诊断中的价值。方法:对2009-11—2010-10在我科经临床检查疑似牙根纵裂的69例病人(84个患牙)的根尖X线片及CBCT图像资料进行回顾性分析。由2位有经验的牙体牙髓科主治医生独立阅片,商讨达成一致后,与根尖切除、牙周翻瓣、拔除术等外科手术所见结果进行比较。并将CBCT与根尖X线片对牙根纵裂的诊断结果进行统计学分析。结果:CBCT诊断根裂的阳性检出率、灵敏度、准确度分别为82.1%、87.3%、88.1%,而根尖X线则为39.3%、41.8%、45.2%,差异有统计学意义(P<0.05)结论:CBCT与根尖X线片相比可更准确的诊断牙根纵裂,具有重要的临床应用价值。     

Microorganisms from canals of root-filled teeth with periapical lesions

AIM: The objective of the present study was to identify the microbial flora within root canals of teeth with failed root-canal treatment and to determine the association of the various species with clinical features. METHODOLOGY: Sixty root-filled teeth with persisting periapical lesions were selected for this study. During nonsurgical endodontic re-treatment, the root-filling material was removed and the canals were sampled. Microbial sampling, isolation and species determination were performed using advanced microbiological techniques for anaerobic species. The association of microbiological findings with clinical features was investigated. RESULTS: Microorganisms were recovered from 51 teeth. In most cases, one or two strains per canal were found. Of the microbial species isolated, 57.4% were facultative anaerobic species and 83.3% Gram-positive microorganisms. Enterococcus faecalis was the most frequently recovered bacterial species. Obligate anaerobes accounted for 42.6% of the species and the most frequently isolated genera was Peptostreptococcus. which was associated with clinical symptoms (P < 0.01). Significant associations were also observed between: (a) pain or history of pain and polymicrobial infections or anaerobes (P < 0.05): (b) tenderness to percussion and Prevotella intermedia/P. nigrescens (P < 0.05); (c) sinus and Streptococcus spp. (P < 0.001) or Actinomyces spp. (P < 0.01); (d) coronally unsealed teeth and Streptococcus spp. or Candida spp. (both with P < 0.01). CONCLUSION: The microbial flora in canals after failure of root-canal treatment were limited to a small number of predominantly Gram-positive microbial species. Facultative anaerobes, especially E. faecalis, were the most commonly isolated microorganisms, however, polymicrobial infections and obligate anaerobes were frequently found in canals of symptomatic root-filled teeth.     

不同根管消毒方法对慢性根尖周炎根管内毒素 清除效果的临床研究

目的 研究Nd:YAG激光照射、超声冲洗及氢氧化钙封药等根管消毒方法对慢性根尖周炎患牙根管内毒素的清除效果.方法 选择临床诊断为慢性根尖周炎的上颌单根管前牙30颗,随机分为3组,镍钛器械常规预备后,分别采用Nd:YAG激光照射(A组)、超声冲洗(B组)及常规氢氧化钙封药(C组)等方法进行根管消毒,检测各组患牙治疗前后根管内内毒素的含量变化.结果 3组患牙治疗前内毒素含量的差异无统计学意义(P>0.05);A、B、C 3组患牙治疗前、预备后、治疗后内毒素含量差异均有统计学意义(P<0.05);治疗后3组间差异无统计学意义(P>0.05).结论 Nd:YAG激光照射、超声冲洗、氢氧化钙封药3种消毒方法均有较强清除灭活根管内毒素作用;50mjNd:YAG激光消毒1min或无菌蒸馏水超声冲洗1min可起到与氢氧化钙封药相同的根管内毒素清除效果.     

A comparison of stainless steel and nickel-titanium K-files in curved root canals

The purpose of this study was to determine the effects of hand instrumentation using traditional stainless steel K-files and nickel-titanium K-files on the final shape of curved root canals. A total of 24 moderately curved canals in the mesial roots in extracted human mandibular first molars were randomly divided into two groups. These were instrumented manually using either stainless steel or nickel-titanium, K-files with the stepdown technique. The cross-sectional shape of each canal at three different horizontal levels were captured, before and after instrumentation, into a computer for comparison using image analyser software. Three parameters at each level were evaluated: (i) amount of dentine removed; (ii) least remaining dentine thicknesses on mesial and furcal aspects; and (iii) the amount and direction of canal transportation. The results showed that the two file types removed similar amounts of dentine at all three levels examined. The nickel-titanium files left a thicker layer of dentine on both the mesial and furcal aspects than stainless steel files. However, the difference was not significant (pooled T-test, P > 0.05). Both types of files transported the centre of the canals but the nickel-titanium instrument seemed to be safer because of the reduced amount of transportation towards the danger areas.     

不同根管充填技术对椭圆形根管的根尖封闭效果

目的 探讨采用不同根管充填技术对椭圆形根管根尖封闭效果的影响.方法 选取近期拔除的椭圆形单根管前磨牙120颗随机分成6组,每组20颗,采用iRoot-SP和AH-Plus根管封闭剂,结合单尖充填法、连续波热牙胶垂直加压充填法、冷牙胶侧方加压充填法,即单尖iRoot组、热牙胶iRoot组、冷牙胶iRoot组、单尖AH组、热牙胶AH组、冷牙胶AH组,采用染料渗透法观察根尖的微渗漏情况.结果 热牙胶iRoot组、热牙胶AH组的根尖染料渗入深度明显小于单尖iRoot组、单尖AH组(P<0.05);热牙胶iRoot组、冷牙胶iRoot组尖染料渗入深度明显小于热牙胶AH组、冷牙胶AH组(P<0.05);其他的组间两两比较差异均无统计学意义(P>0.05).结论 热牙胶垂直加压技术可以使椭圆形根管达到更好的根尖封闭效果,且配合使用iRoot SP根管封闭剂的封闭效果较配合使用AH-Plus根管封闭剂好.     

Immunoglobulins in periapical exudates of infected root canals: correlations with the clinical findings of the involved teeth

Abstract This study quantified the concentrations of IgG and IgA in the periapical exudates obtained from 69 single-rooted teeth using enzyme-linked immunosorbent assays, and examined their correlation with clinical findings of the involved teeth. Changes in the levels of these immunoglobulins during root canal treatment were also investigated. The average levels of IgG (85.61 mg/ml) was significantly higher than that of IgA (0.65 mg/ml) (P<0.001). The exudates from the canals with large lesions (≥1 cm in diameter on radiographs) showed significantly higher IgG and IgA levels than small lesions (< 1cm in diameter) (P < 0.01). The tendency for these to be a decrease in the levels of IgG and IgA was observed following the root canal treatment. These observations suggest that IgG and IgA are involved in the immunopathogenesis of periapical lesions.     

Scanning electron microscopy of bacteria in the apical part of root canals in permanent teeth with periapical lesions

Abstract The most apical 2 mm of the root canals of periapically diseased roots were examined for microorganisms by scanning electron microscopy (SEM). Bacteria in this area were observed in 10 out of 12 (83.3%) cases. The two remaining cases exhibited bacteria more coronally, with tissue remnants between the bacterial front and the apical foramen. Rod-shaped bacteria dominated, but filaments, spirochetes and cocci were also seen. Cocci and rods sometimes formed micro-colonies. Occasionally, cocci were seen attached to filaments forming “corn-cob”-like structures. Deposits resembling bacterial plaque were also found inside the root canal. SEM is useful for studying microbial topography of the apical root canal.     

Antimicrobial susceptibilities of Eubacterium, Peptostreptococcus, and Bacteroides isolated from root canals of teeth with periapical pathosis

Eubacterium, Peptostreptococcus, and Bacteroides were isolated in high frequency from root canals with acute periapical inflammation. The antimicrobial susceptibilities of these strains were studied by determining minimum inhibitory concentrations of different agents. Although all three kinds of isolates were susceptible to penicillins, the isolates other than black-pigmented Bacteroides were less susceptible to cephems, tetracyclines, and macrorides with several resistant strains. All strains were uniformly resistant to aminoglycosides. Some differences in susceptibilities were observed among species of Eubacterium and Peptostreptococcus, while penicillins were effective for both species. Black-pigmented Bacteroides showed good susceptibilities to all agents except for aminoglycosides. The susceptibility of Bacteroides gingivalis was superior to that of Bacteroides intermedius. There were many resistant strains in non-black-pigmented but not in black-pigmented Bacteroides isolates. Penicillins were the most effective for Eubacterium, Peptostreptococcus, and Bacteroides, indicating that penicillins are suitable for treatment of root canals with acute apical periodontitis.