OBJECTIVETo explore the nursing methods during canal obturation in order to improve efficiency and quality of root canal therapy.

METHODS112 teeth treated by complete root canal preparation were chosen to fill the root canal, and the main points of nursing during canal obturation were summarized.

RESULTSAll of 112 teeth nursed strictly during canal obturation obtained satisfactory efficiency. No one failed after root canal therapy.

CONCLUSIONThe main points of nursing during canal obturation are the aseptic technique, skilled coordination, instrument management, communication between nurses and patients.

PURPOSE: Recently TF-adaptive movement is developed in order to increase the durability of TF files. The purpose of this study was to assess the effects of adaptive movement on durability and performance of twisted files. MATERIALS AND METHODS: Resin blocks simulating artificial J-shape canals were used for this study. In TFC group, TF-adaptive ML-1 (25/.08 size) files were used to prepare the canals under continuous rotation 500 rpm/4.0 Ncm. In TFA group, TF-adaptive ML-1 (25/.08 size) files were used to prepare the canals under adaptive movement. After preparing each artificial canal, TF files were observed under dental microscope for assessing existence of unwinding, distortion, and fracture. If unwinding of flute was observed, the number of artificial canals until unwinding of flute occurs was recorded. Required time until instruments reach working length and distance of unwinded portion of files from D0 were measured. All test results were conducted by Mann-Whitney U test at a 0.05 level of significance. RESULTS: No NiTi instrument's separation was observed. Number of resin blocks until file unwinding happens and working time was significantly high in TFA group compared to TF group. Distance of distortion from D0 didn't show significant difference between TFA, TF groups. CONCLUSION: The number of resin blocks prepared until unwinding happens and working time were significantly high in TFA group. The location of unwinding showed no significant difference between 2 groups. Adaptive movement increased the number of canals prepared until unwinding occurs and working time of twisted files.
Filing ; Movement ; Root Canal Preparation

OBJECTIVETo investigate the effects of root canal preparation treated by endodontists of different levels in different difficulty associated with the root canal anatomy factors.

METHODSTotally 422 teeth with 901 root canals were randomly selected from the Conservative Dentistry Department, West China Stomatology Hospital, and these teeth were respectively treated by junior specialist postgraduates, senior specialist postgraduates and endodontic specialists. Grading criteria of root canal risk factor and root canal therapy difficulty assessment were found based on 6 items: Tooth type, working length, root curvature, calcification, number of canals, and the previous endodontic treatment. The effects of root canal preparation with different difficulty in different groups were analyzed with RxC Chi-square test.

RESULTSSuccess rates of root canal preparation in junior group and senior group during three difficulty groups were statistically different (P < 0.05), and the root canal therapy difficulty group I > group II > group III. The operator factors in root canal therapy difficulty group I and group II were not significantly different P > 0.05). But in root canal therapy difficulty group III, the endodontic specialist group have highest success rate in root canal preparation.

CONCLUSIONThe cases of root canal treatment should be treated by endodontist of corresponding level according to the difficulty. In difficult cases, endodontic specialist can provide better root canal preparation result.

Dental Pulp Cavity ; Humans ; Root Canal Preparation ; Root Canal Therapy

OBJECTIVETo study and evaluate the clinical effect of root canal therapy bypassing intracanal separated instruments.

METHODS32 teeth were selected as the test group, from which the intracanal separated instruments couldn't be taken out, adopted the method of root canal preparation and obturation bypassing broken instruments. Meanwhile, 13 teeth were selected as the control group, in which the fractured instruments couldn't be taken out from root canal, and not be cured bypassing broken instruments. 30 teeth were selected as the conventional therapy group, in which the instruments were not fractured, the routine root canal therapy were adopted. The clinical efficacy of three groups were observed and evaluated through periapical index and clinical examination two years later.

RESULTSAfter two years, 25 teeth were followed up in test group, the success rate of root canal therapy was 80.00%; 11 teeth were followed up in control group, the success rate of root canal therapy was 36.36%. All of the failed cases in two groups were the teeth with broken instruments in tip of root canal. In conventional therapy group, 22 teeth were followed up, and the success rate of root canal therapy was 90.91%.

CONCLUSIONRoot canal therapy bypassing intracanal separated instruments is a feasible and effective method in treating the teeth with broken instruments.

Successful endodontic treatment depends on the effectiveness of the cleaning and shaping of the root canal system. Due to the complexity of the structure of root canal system and the particularity of root canal infections, the equipment and technology currently available for root canal preparation hinder the ability to adequately clean and shape the root canal system. In this review, we summarized the difficulties in the control of root canal infection, the new concept of three-dimensional root canal preparation, and its quality control and assessment.
Dental Pulp Cavity ; Root Canal Preparation ; Root Canal Therapy

OBJECTIVES: This study aimed to compare two nickel-titanium systems (rotary vs. reciprocating) for their acceptance by undergraduate students who experienced nickel-titanium (NiTi) instruments for the first time. MATERIALS AND METHODS: Eighty-one sophomore dental students were first taught on manual root canal preparation with stainless-steel files. After that, they were instructed on the use of ProTaper Universal system (PTU, Dentsply Maillefer), then the WaveOne (WO, Dentsply Maillefer). They practiced with each system on 2 extracted molars, before using those files to shape the buccal or mesial canals of additional first molars. A questionnaire was completed after using each file system, seeking students' perception about 'Ease of use', 'Flexibility', 'Cutting-efficiency', 'Screwing-effect', 'Feeling-safety', and 'Instrumentation-time' of the NiTi files, relative to stainless-steel instrumentation, on a 5-point Likert-type scale. They were also requested to indicate their preference between the two systems. Data was compared between groups using t-test, and with Chi-square test for correlation of each perception value with the preferred choice (p = 0.05). RESULTS: Among the 81 students, 55 indicated their preferred file system as WO and 22 as PTU. All scores were greater than 4 (better) for both systems, compared with stainless-steel files, except for 'Screwing-effect' for PTU. The scores for WO in the categories of 'Flexibility', 'Screwing-effect', and 'Feeling-safety' were significantly higher scores than those of PTU. A significant association between the 'Screwing-effect' and students' preference for WO was observed. CONCLUSIONS: Novice operators preferred nickel-titanium instruments to stainless-steel, and majority of them opted for reciprocating file instead of continuous rotating system.
Humans ; Molar ; Root Canal Preparation ; Students, Dental

The aim of this study was to evaluate the microleakage of teeth according to root canal preparation with & without apical enlargement in various size of apical foramen. 60 extracted one canal roots were cross-cutted at 5 mm from root apex and divided into two groups according to their apical foramen size of large (L) and small (S). Each group was subdivided into two groups accordance with their cross-sectional configuration at 5 mm from apex, round (R) and ovoid (O); SR Group, SO Group, LR Group, LO Group. Each group was shaped in .02 taper by Quantec series Nickel-Titanium (NiTi) rotary file, obturated by lateral condensation method. Leakage was measured using a fluid transport model under 40 cmH2O pressure. After the leakage test, blocks which had showed the leakage retreated with .04 taper and .06 taper and evaluated the degree of fluid filtration in each group. The data was analysed statistically using chi-square test and fisher's exact test. The results obtained were as follows: 1. Significant difference in leakage was found in groups which had different apical foramen size in .02 taper instrumentation (p < 0.05), but not in .04 taper instrumentation (p > 0.05). 2. The difference in microleakage according to the shape of canal was not evident at 5 mm from apex (p > 0.05). 3. There was correlation between .02 taper instrumentation and .04 taper instrumentation in LR group , LO group (p < 0.05).
Filtration ; Root Canal Preparation ; Tooth Apex ; Tooth*

Screw-in effect is one of the unintended phenomena that occurs during the root canal preparation with nickel-titanium rotary files. The aim of this study was to compare the screw-in effect among various nickel-titanium rotary file systems. Six different nickel-titanium rotary instruments (ISO 20/.06 taper) were used: K3(TM) (SybronEndo, Glendora, CA, USA), Mtwo (VDW GmbH, Munchen, Germany), NRT with safe-tip and with active tip (Mani Inc., Shioya-gun, Japan), ProFile(R) (Dentsply-Maillefer, Ballaigues, Switzerland) and ProTaper(R) (Dentsply-Maillefer, Ballaigues, Switzerland). For ProTaper(R), S2 was selected because it has size 20. Root canal instrumentations were done in sixty simulated single-curved resin root canals with a rotational speed of 300 rpm and single pecking motion. A special device was designed to measure the force of screw-in effect. A dynamometer of the device recorded the screw-in force during simulated canal preparation and the recorded data was stored in a computer with designed software (LCV-USE-VS, Lorenz Messtechnik GmbH, Alfdorf, Germany). The data were subjected to one-way ANOVA and Tukey's multiple range test for post-hoc test. P value of less than 0.05 was regarded significant. ProTaper(R) produced significantly more screw-in effects than any other instruments in the study (p < 0.001). K3(TM) produced significantly more screw-in effects than Mtwo, and ProFile(R) (p < 0.001). There was no significant difference among Mtwo, NRT, and ProFile(R) (p > 0.05), and between NRT with active tip and NRT with safe one neither (p > 0.05). From the result of the present study, it was concluded, therefore, that there seems significant differences of screw-in effect among the tested nickel-titanium rotary instruments. The radial lands and rake angle of nickel-titanium rotary instrument might be the cause of the difference.
Dental Pulp Cavity ; Root Canal Preparation

No abstract available.
Dental Pulp Cavity* ; Root Canal Preparation*