Effect of argon laser irradiation on instrumented root canal wall

Abstract— The objective of the study was to examine whether argon laser has a property to remove debris and smear layer from root canal walls. Twelve endodontically treated human maxillary molar teeth with three root canals were divided into two groups of six teeth. The first group was left unlased as a control; in the second group the root canals were irradiated by argon laser (laser parameters were set at 1 W and pulse duration and pulse frequency fixed at 0.05 s and 5 Hz). After the usual root canal preparation and lasing had been camed out, the teeth were decoronated, bisected longitudinally, observed with a scanning electron microscope and evaluated as to how clean the surfaces of root canal walls were. In most cases control teeth presented surfaces with debris covering the root canals, obscuring the dentinal tubules. Only 1 of 18 specimens was free of debris. In the lased group, root canal surfaces free of debris and vaporized pulpal tissue remnants were observed in 13 of 18 specimens. The results showed sigmficant statistical differences between the control group and the lased groups (P<0.001). These results suggested that argon laser irradiation has an efficient cleaning effect on instrumented root canal surfaces.     

Neurological complications following extrusion of sodium hypochlorite solution during root canal treatment

AIM: To report the presentation and management of two cases with neurological complications secondary to the extrusion of sodium hypochlorite solution into the facial soft tissues during root canal treatment. SUMMARY: The clinical features, with particular emphasis on nerve deficit following inadvertent extrusion of sodium hypochlorite, are discussed and its management highlighted. Early and aggressive treatment is advocated following such incidents in order to reduce potentially serious complications. KEY LEARNING POINTS: *Neurological sequelae can follow inadvertent hypochlorite extrusion. *Early recognition may avert a potentially more serious outcome. *Active hospital treatment including intravenous steroids and antibiotics is recommended.     

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近15年来,影响根管治疗质量的最重要因素之一就是手术显微镜的引入和推广应用。手术显微镜多级放大功能和良好的照明技术,使医生能够看清髓室底及根管内部结构,精确定位手术位置,把握操作细节,从而改善并提高根管治疗术的质量。显微根管治疗可以对传统根管治疗无法完成或难以完成的病例包括根管遗漏、塑化根管、钙化根管、根管台阶形成、器械断针、侧壁穿孔等进行治疗,使更多患牙得以保留。本文结合笔者的临床经验及国内外文献,对根管手术显微镜的组成、显微治疗辅助设备器械的功能和显微镜在疑难根管治疗中的应用等进行评述。强调根管显微镜在疑难病例治疗中的重要性和必要性,并提出在进行显微根管治疗前须进行显微镜应用技巧培训。     

根管治疗过程中影响牙根纵裂的因素

牙根纵裂最常发生于根管治疗之后且临床症状不具有明显的特异性,常常症状不明显,早期诊断较为困难,常出现漏诊和误诊。本文从病因学的角度出发,针对根管治疗过程中的每个步骤,就牙根纵裂的影响因素作一综述,以供临床操作参考。     

Comparative debridement study between hand and sonic instrumentation of the root canal

Abstract The cleaning efficiency of hand and sonic instrumentation with MM Sonic 3000 in 60 single-rooted human straight teeth was evaluated using light and scanning electron microscopy. The root canals were instrumented with K-type files and Shaper Sonic files, respectively, and manually irrigated with 1 % sodium hypochlorite. The results showed no statistically significant difference between hand and sonic instrumentation. In both groups a smear layer, untouched predentin and pulp tissue debris were generally observed.     

Periapical status, quality of root canal fillings and estimated endodontic treatment needs in an urban German population

Abstract The objective of this study was to determine the periapical status and the quality of root canal fillings and to estimate the endodontic treatment needs in a German population. Clinical and radiographic data and the operative procedures performed were evaluated on 323 patients coming to a dental surgery in Stuttgart, Germany, in 1993. In 182 individuals at least one tooth exhibited a root canal filling, a necrotic pulp or an irreversible pulpitis. Out of the 7897 teeth examined, 215 (2.7%) had a root canal treatment (category A), 122 being nonendodontically treated (1.5%) did not respond to the sensitivity test (category B) and 53 (0.7%) were diagnosed as having irreversible inflamed pulp tissue (category C). The prevalence of teeth associated with radiographic signs of periapical pathosis was 61 % in the group of root canal filled teeth and 88% in the group of pulpless and non-endodontically treated teeth. Using the level and the density of the root canal filling as criteria for evaluating the technical standard, only 14% of the endodontic treatments of non-apicectomized teeth were qualified as adequate. The minimal endodontic treatment need is 2.3% related to all examined teeth when the root canal filled teeth with clinical symptoms of periapical periodontitis (category A) and those of categories B and C are included. The real endodontic treatment need is suggested to be larger when considering that the technical quality of the obturation is poor in most symptomless endodontically treated teeth associated with a periapical lesion. In the case of retreatment of these teeth, the endodontic treatment need would then be calculated at 3.7%.     

Effect of laser treatment on the root canal of human teeth

Abstract The purpose of this study was to examine the morphological and temperature changes of the apical portion of human extracted teeth treated by Nd: YAG, CO₂ and Argon-lasers. Seventy-two single-rooted human teeth were studied. The root canals were prepared conventionally. Laser treatment of the apical portion of the canal was carried out by means of an optic fiber or metal tip. Temperatures were recorded thermographically. Two-thirds of the specimens were stained with black India ink and 36% silver ammonium fluoride solution. All specimens were irradiated by the three types of lasers at several intensities and the temperatures were recorded. Half of the specimens were prepared for the telescopic light microscope and for scanning electron microscopic observation, and the rest for histopathological examination by light microscope. The scanning electron microscopic evaluation showed that the laser energy vaporized the deposited debris, producing a glaze-like surface. The histopathological investigation revealed a tapered, enlarged apical lased area. All three laser devices were capable of vaporizing the debris in this way, but the degree of morphological change was highly dependent on energy level and duration. The Argon-laser produced the highest temperatures.     

Efficacy and safety tests of six automated devices for root canal instrumentation

Abstract it was the purpose of this study to lost the efficacy and safety of automated devices for root canal instrumentation. Instruments tested were Giromatic with (a) barbed broaches and Hedstrom files, and (b) RISPI files; Dynatrak with Unifiles; Canal Finder System with K-files and modified Hedstrom files; Cavi-Endo with K-files and diamond-coated instruments; Endostar 5 with K-files; and MM sonic 3000 with (a) RISPI files, and (b) Sonic Shapers. Transparent plastic models with simulated root canals of various widths and shapes were used. The canals were enlarged by 0.2 mm at their apices and the instrumentation time-was recorded. Complications during instrumentation were also recorded. With regard to efficacy, 3 devices stood out among the instruments tested: Giromatic with RISPI files, the Canal Finder System, and the MM Sonic 3000. With the Canal Finder System and the MM Sonic 3000 the tests were completed without complications. It was concluded that automated devices for endodontic treatment are now available that are both efficient and remarkably safe.     

Shape of the root canal after ultrasonic instrumentation with K-Flex files

Abstract This study investigated the feasibility of using K-Flex files with the Cavi-Endo ultrasonic unit. The effectiveness of the K-Flex files in shaping canals was compared with the ultrasonic Cavi-Endo K-files. Simulated curved canals in clear resin blocks were instrumented ultrasonically using the 2 file types. Pre- and postinstrumentation photographs were taken and the following were evaluated: apical and coronal areas, the incidence of the narrowing of the canals coronal to the apical transport (elbows). Displacement amplitude measurements were carried out in order to see any relationship between the incidence of elbows and displacement amplitudes of the files. The results indicated that the K-Flex files were more efficient than the ultrasonic K-files and resulted in less elbow formation. No direct relationship was observed between displacement amplitudes and the incidence of elbow formation. It is suggested that the manufacturers of ultrasonic units consider different file designs.     

A histobacteriological assessment of nonvital teeth after ultrasonic root canal instrumentation

Abstract The purpose of this study was to evaluate and discuss the bactericidal effect of ultrasound when applied in the root canal of teeth with necrotic pulp and periapical lesions. Twenty newly extracted teeth were instrumented with an ultrasonic unit and K-files using 0.5% sodium hypochlorite as irrigating solution. Compacted debris and micro-organisms were frequently observed in the apical region and in dentinal tubules of the root canal wall. Overinstrumentation that sometimes occurred led to contamination of the periapical lesions with micro-organisms and debris from the root canal.     

Root canal treatment in general practice in Sudan

AIM: The aim of this study was to evaluate the practice and depth of knowledge of root canal treatment by dental practitioners in Khartoum, the capital city of Sudan, in order to improve the current status of endodontic therapy. METHODOLOGY: A questionnaire was posted to 55 registered dental practitioners. Completed questionnaires were analysed in term of simple summary statistics. RESULTS: A total of fifty-two (95%) practitioners responded. Eighty-five per cent of the respondents indicated that they performed root canal treatment for their patients. Of these, 84% included molars in their activity. Amongst those who carried out root canal treatment, only one practitioner used rubber dam for isolation, whilst the remainder used cotton wool rolls. The majority of respondents (80%) used hydrogen peroxide to irrigate canals during treatment. Three-quarters of practitioners used formocresol as an inter-appointment medicament. The stepback preparation technique was the method of choice for 98% of respondents. All practitioners used hand instruments to prepare root canals and all used gutta-percha for obturation; three-quarters of them used cold lateral condensation for all or some cases. The average number of radiographs routinely taken for root canal treatment was three. Only 73% used radiographs for measuring the working length. Ninety-five per cent of respondents indicated that they usually completed a root filling in three or more visits. Three-quarters of practitioners restored the teeth permanently immediately after the obturation and one-quarter preferred waiting for 1 or 2 weeks. CONCLUSIONS: In Sudan, there are no dental practices limited to endodontics and no postgraduate training programmes. This survey shows the importance of establishing higher specialist training or continuing dental education for practitioners to update their knowledge.     

The principles of techniques for cleaning root canals

Chemomechanical preparation of the root canal includes both mechanical instrumentation and antibacterial irrigation, and is principally directed toward the elimination of micro-organisms from the root canal system. A variety of instruments and techniques have been developed and described for this critical stage of root canal treatment. Since their introduction in 1988, nickel-titanium (NiTi) rotary instruments have become a mainstay in clinical endodontics because of their exceptional ability to shape root canals with potentially fewer procedural complications. Safe clinical usage of NiTi instruments requires an understanding of basic metallurgy of the alloy including fracture mechanisms and their correlation to canal anatomy. This paper reviews the biologic principles of preparing root canals with an emphasis on correct use of current rotary NiTi instrumentation techniques and systems. The role and properties of contemporary root canal irrigants is also discussed.     

Efficacy of different irrigation methods and concentrations of root canal irrigation solutions on bacteria in the root canal

Abstract The effectiveness of two different root canal irrigating solutions, each in two different concentrations or formulations, with two different irrigation methods was compared in vitro by means of bacterial survival determinations. 75 human root canals were enlarged, sterilized and inoculated with a mixed culture of Escherichia coli and Streptococcus mutatis. After inoculation, the root canals were irrigated either manually or with an ultrasonic-device for equal times (20s) with the same amount (5 ml) of sodium hypochlorite (1% and 2%). Fokalhydran I and Fokalhydran II. Sodium hypochlorite (1% and 2%) was used in a 1:100 dilution. Fokalhydran 1 and II were used in a 1:10 dilution. In the sodium hypochlorite group, the 1% concentration applied with a syringe proved to be most effective against Escherichia coli and Streptococcus mutans. The least effective concentration and application method against both bacteria species was obtained with 2% NaOCL and ultrasonics. Against Escherichia coli and Streptococcus mutans, a significantly lower effectiveness was found with 2% NaOCL applied with ultrasonics with respect to the rest of the sodium hypochlorite group. Fokalhydran I was significantly better than Fokalhydran 11 against Escherichia coli. However, no significant differences could be seen against Streptococcus mutans within this group.     

一次根管治疗术与两次根管治疗术术后短期临床疗效的比较

目的比较一次根管治疗术与两次根管治疗术术后短期临床疗效,并分析不同因素对疗效的影响。方法将96例需行根管治疗的患者随机分成2组,分别进行一次根管治疗术（一次治疗组）和两次根管治疗术（两次治疗组）,并在术后的1、3d和1周进行随访,记录其疼痛情况,术后3个月行影像学检查,评估分析其短期疗效。结果一次治疗组和两次治疗组在术后短期疼痛和影像学检查方面的差异均无统计学意义;患者的性别及患牙术前根尖周指数（PAI）对根管治疗的术后疗效有一定影响,而患者年龄、患牙解剖牙位、患牙牙髓情况（未出现根尖周病损）的差异对根管治疗术术后疗效影响意义不大。结论一次性根管治疗在术后短期的疼痛发生率较低,在临床可根据实际情况推广应用;患者性别及术前PAI会影响根管治疗的术后疗效。     

In vitro cleaning ability of root canal irrigants with and without endosonics

A variety of methods have been used to evaluate the cleanliness of root canals after endodontic preparation and irrigation. Few irrigation agents other than sodium hypochiorite (NaOCl) have been tested in conjunction with endosonics. The purpose of this study was to examine the cleaning ability of water, NaOCl, Hibiscrub and a biological washing liquid when used as intracanal irrigants, with and without endosonics. Two methods of evaluation were employed to assess the root canal cleanliness after endodontic preparation. A total of 56 teeth, divided into eight groups, were prepared manually using the step-down technique. Each irrigating agent was used in two experimental groups, with and without endosonics. Two additional teeth which received neither instrumentation nor irrigation served as the controls. The teeth were split longitudinally and the state of cleanliness of the root canal was assessed by scoring the amount of stained organic debris and smear layer. It was demonstrated that the results of debris and smear layer scoring were significantly influenced by the type of irrigant and whether endosonics had been used. All agents exhibited similar cleaning ability when introduced manually. With endosonics, NaOCl yielded significantly less stainable debris (P < 0.05) than the other groups which showed no significant difference. The ability to remove the smear layer was enhanced, but at some distance short of the working length, by endosonics for all irrigants tested. None of the solutions tested was able to produce a canal wall that was free of smear layer.     

下颌第二前磨牙牛牙症伴C型根管的显微治疗一例

牛牙症、C型根管在下颌第二前磨牙的发生率均极低.本文报道1例罕见下颌第二前磨牙牛牙症伴C型根管病例,展示锥形束CT影像学分析和显微根管技术在该病例诊治中的联合应用,为该特殊类型根管的临床治疗提供新思路.