The physical characterization of a thermoplastic polymer for endodontic obturation

OBJECTIVE: To analyze a new endodontic sealer material commercially known as Resilon and to describe in detail the experimental techniques employed that lead to the identification of the composite material. METHODS: An extensive structural, thermal, and physical characterization was used to identify a new endodontic sealer material using the following techniques: Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) analysis, X-ray fluorescence spectrometry (XRF) technique, X-ray diffraction (XRD) measurement, thermo-gravimetric analysis (TGA) and a differential scanning calorimeter (DSC). The surface morphology was analyzed using a scanning electron microscope (SEM). RESULTS: The material was identified as a composite of polycaprolactone, which is a polymer of the polyester family and bioactive glass, which is radiopaque filler. CONCLUSIONS: The Resilon sealer material is a thermoplastic synthetic degradable polymer (polycaprolactone), it contains bioactive glass. Its properties, such as strength, modulus, shape-memory effect and biodegradability depend on the crystalline fraction, which is affected in turn by conditions of crystallization. Investigation of the crystallization kinetics of PCL is of practical significance. It is especially necessary to study its the dynamic and non-isothermal crystallization process.     

Safety of dental implant surgery in patients undergoing anticoagulation therapy: a prospective case-control study

Objectives: Several studies have described oral surgical procedures in patients receiving anticoagulant therapy, but no prospective studies on dental implant surgery during anticoagulant treatment are currently available, and only a limited number of case reports refer to endosseous dental implant treatment in these patients. In the setting of oral surgery, it has been suggested that anticoagulant treatment is not required when the International Normalized Ratio (INR) is <4 and local haemostatic measures are applied. The purpose of this preliminary study was to evaluate the incidence of bleeding complications following surgical implant therapy in a group of 50 consecutive patients receiving oral anticoagulant therapy (warfarin) without interruption or modifications to their therapy (group A). Materials and methods: One hundred and nine otherwise healthy patients comparable for age, sex, extent and site of the implant surgical procedure formed the control group (group B). In both groups, a standard protocol of local haemostasis, including non‐reabsorbable sutures and compressive gauzes soaked with tranexamic acid, was applied. Surgeons, blind to the group allocation, performed all the procedures in an outpatient setting. Results: Two and three late‐bleeding complications were reported in group A and group B, respectively, without significant difference in the bleeding risk (relative risk = 1.45; P= 0.65; 95% confidence interval 0.2506–8.4271). These complications were managed using a compressive gauze soaked with tranexamic acid at the site of the surgical wound. Conclusion: According to our preliminary results, local haemostasis in dental implant surgery is able to prevent bleeding complications in patients on oral anticoagulants, allowing these surgical procedures to be performed on an outpatient basis. To cite this article:
Bacci C, Berengo M, Favero L, Zanon E. Safety of dental implant surgery in patients undergoing anticoagulation therapy: a prospective case–control study.
Clin. Oral Impl. Res. 22 , 2011; 151–156.
doi: 10.1111/j.1600‐0501.2010.01963.x     

大锥度牙胶尖与两种镍钛机动根管预备锉的匹配性研究

目的评价大锥度牙胶尖与两种机动镍钛根管预备锉的匹配性。方法选择40只离体后牙根管,根据初尖锉的号码和近远中向根管弯曲度分为2组,分别以ProTaper和ProFile两种机动镍钛根管锉完成根管预备,插入大锥度牙胶尖进行试尖,比较两者的匹配性。结果ProTaper F1、F2、F3与0.06锥度/20、253、0号牙胶尖的匹配率分别为80%、88%、92%,均较同锥度大1号的牙胶尖匹配率高,差异有显著性(P<0.01)。ProFile 0.06锥度/30号和40号与0.04锥度同号牙胶尖的匹配率最高,分别为83%和96%,其次是0.06锥度小1号牙胶尖,而与0.06锥度同号牙胶尖匹配率最低,分别为35%和25%,3者间差异有显著性(P<0.01)。结论大锥度镍钛机动器械预备的根管,与主尖锉同号而锥度减小或锥度相同且小1号的大锥度牙胶尖有良好的匹配性。     

The effect of cleaning on blood contamination in the dental surgery following periodontal procedures

Blood contamination of 16 surfaces in the dental surgery was investigated using the Kastle-Meyer test for haemoglobin, after three types of periodontal procedures had been performed on a total of 30 patients. The effect of cleaning surfaces contaminated by blood was investigated using the same test. Cleaning materials used in the dental surgery were tested to rule out the possibility of false positive outcomes and the sensitivity of the test was determined prior to the study. The results show a marked variation in the degree of contamination and efficacy of cleaning following treatment. Overall, root planing was associated with the most widespread and frequent blood contamination and gingival surgery the least. The surgery work surface, edge of the spittoon, aspirator tube and ultrasonic scaler handpiece into which the ultrasonic insert fits, were the most frequently contaminated surfaces. The work surface, dentist's pen, light switch and handle were cleaned most effectively. The least effectively cleaned surfaces were the water dispenser switch, aspirator tube, bracket table and ultrasonic scaler handpiece. Methods for reducing this potential source of crossinfection are discussed.     

Clinical effects after subgingival polishing with a non-aggressive ultrasonic device in initial therapy

OBJECTIVES: The Vector ultrasonic system provides root debridement supported by different abrasive irrigation fluids. The aim of this study was to investigate the clinical outcome of initial therapy with subgingival low-abrasive debridement. MATERIAL AND METHODS: Twenty patients, who had at least two teeth with pocket depths >5 mm in each quadrant, took part in this prospective randomized clinical study. Patients were treated in a split-mouth design as one test quadrant (1) subgingivally with Vector fluid polish (VU-H) and as three control quadrants, (2) with only supragingival polishing (PO-H), (3) with hand instruments (HI-H) performed by a hygienist and (4) with hand instruments (HI-D) performed by a dentist. At baseline, 3 and 6 months after treatment, pocket depths and attachment levels (ALs) were measured and bleeding on probing (BOP) was recorded. RESULTS: At 6-month evaluation, all groups showed an improvement in clinical parameters. No statistically significant differences in any of the investigated parameters could be observed between the Vector group and the hand scaling groups, or when comparing the results of the two different operators. CONCLUSION: This study demonstrates that Vector treatment with polishing fluid was able to reduce pocket depths and the prevalence of BOP and improve clinical AL in a similar way as scaling with curettes.     

小剂量地塞米松预防根管治疗期间慢性尖周炎急性发作的临床研究

目的 探讨小剂量地塞米松对根管治疗期间慢性尖周炎急性发作的预防作用。方法 90倒下前磨牙慢性尖周炎患者以年龄性别分层，随机化配对分成A、B、C三组：A组每日口服地塞米松1．5mg，每日2次；B组每日口服地塞米松1．5mg，每日1次；C组为空白对照。分别于根管预备后6、24、48小时记录VAS评分。结果 A、B组与C组VAS评分经方差分析，差异具有高度统计学意义。A、B组VAS评分均值t检验差异无统计学意义。结论每日口服地塞米松1．5mg可有效预防根管治疗期间慢性尖周炎急性发作。     

手用镍钛锉对弯曲根管根管成形能力的评价

目的：评价手用镍钛锉（ISO）预备弯曲根管时的根管成形能力。方法：利用自主研制的《牙齿模拟根管辅助分析测量系统》软件，定量检测8个模拟根管在用手用镍钛锉（ISO）以提拉方式预备前后的形态变化，并进行统计学分析。结果：手用镍钛锉（ISO）虽有良好的弹性，但以四壁提拉方式预备根管时仍有明显拉直根管的趋势。手用镍钛锉对弯曲根管的各部位切割很不均衡。结论：结果提示仅有弹性好的手用镍钛锉并不能保证获得弯曲根管预备的良好效果，预备方式和手法的改进是弯曲根管预备所必须的。     

A systematic approach to preventing intracanal breakage of endodontic files

Abstract This study was conducted to determine the effectiveness of a method to prevent intracanal breakage of endodontic files. An application schedule with a predetermined number of periods of use for K-files of all sizes was implemented at the author's clinic for a 3-year period. All the files used under this schedule were discarded after the predetermined periods of use, whether they displayed any deformity or not. During the 3-year period, 1933 files (53.7 per month) were discarded after preparation of 3269 root canals. There were 5 file fractures (0.1 per month) compared with 1.4 fractures per month before the adaption of this system. The monthly average of files discarded during the 3-year research period was 53.7. Before the adoption of the trial system, the monthly average of discarded files was 76.5. It is concluded that the experimental system effectively reduced the incidence of intracanal instrument fractures and the total number of files consumed.