Effects of simulated lateral canals on the accuracy of measurements by an electronic apex locator.

BACKGROUND: Accurate determination of the apical terminus plays a significant role in the success of root canal therapy, but accuracy may be affected by the presence of accessory canals. OBJECTIVE: To evaluate the accuracy of a ratio-based electronic apex locator for roots with simulated lateral canals. METHODS: Forty-two single-rooted human teeth were randomly divided into 2 groups. For each tooth, the root canal was prepared to the visually determined working length, and the working length was then measured with the Justy II electronic apex locator. Simulated lateral canals (of 2 different diameters) were then prepared at 3 mm (group A) or 6 mm (group B), and the working lengths were measured again with the same instrument. The measurements were analyzed by one-way analysis of variance. RESULTS: For both groups, there were no significant changes in working length after the creation of simulated canals (p > 0.05). CONCLUSION: Measurements obtained with the ratio-based electronic apex locator were not affected by the preparation of simulated lateral canals, and the instrument was able to accurately determine the location of the tooth apex.

Second mesiobuccal canal detection in maxillary first molars using microscopy and ultrasonics.

The aim of this study was to investigate whether the use of operating microscope in combination with ultrasonics increased the rate of second mesiobuccal (MB2) canal detection in permanent maxillary first molar teeth. A hundred extracted human maxillary first molars were assessed. After location of the main canals, the MB2 canal was sought in all teeth first without microscopy, then with the aid of the operating microscope and finally with the combined use of the operating microscope and ultrasonics. With these techniques, the MB2 canal was detected in 62%, 67% and 74% of the teeth, respectively. The combination of the operating microscope and ultrasonics detected significantly more MB2 canals than when no microscopy was utilized (P < 0.05). Sectioning of the roots disclosed the presence of the MB2 canal in 82% of the teeth. Twenty-nine per cent of the teeth had a separate MB2 canal orifice and separate apical foramina. The results of this study suggested that the combined use of the operating microscope and ultrasonics increased the detection of MB2 canals in maxillary first permanent molars.

Staining potential of calcium hydroxide and monochlorophenol following removal of AH26 root canal sealer.

AIM: The focus of this study was to examine the staining potential of calcium hydroxide (Ca(OH)2) on tooth structure following the removal of AH26 root canal sealer. METHODS AND MATERIALS: Fifty maxillary anterior teeth were prepared and obturated with AH26 and gutta percha. The sealers were then removed 24 hours later and the teeth were randomly divided into two groups. Ca(OH)2 was then placed in the root canals of the first group of teeth as a medicament and camphorated monochlorophenol (CMCP) was placed in the second group of teeth after the filling material was removed. The color of the external tooth surfaces was determined before tooth preparation and two weeks after the placement of the medicaments. The Z test was used for statistical analysis. RESULTS: All experimental teeth showed varying degrees of coronal discoloration with the Ca(OH)2 group showing more discoloration than the CMCP group (p<0.05). CONCLUSION: Using Ca(OH)2 as a medicament after removing AH26 caused progressive discoloration of the teeth, whereas using CMCP caused only slight discoloration. CLINICAL SIGNIFICANCE: To avoid staining of the treated tooth, AH26 root canal sealer must be completely removed from the dentin walls before using a medicament.

Accuracy of two different apex locators in primary teeth with and without root resorption.

The objective of this study was to assess the accuracy of two frequency apex locators, Root ZX (Morita, Kyoto, Japan) and Endex (Osada, Tokyo, Japan) in primary teeth with and without root resorption in vitro. For this study, 90 sound extracted primary teeth (60 molars and 30 incisors; 93 roots with visible resorption and 51 roots without) were selected. A total of 144 root canals were included. After access preparation, root canal lengths were measured visually. The teeth were embedded in an alginate model developed specifically for testing apex locators. Electronic length was determined with two different frequency apex locators, Root ZX (Morita, Kyoto, Japan) and Endex (Osada, Tokyo, Japan). Statistical evaluation was performed using Mann-Whitney U and Wilcoxon W tests (p < 0.05). Results revealed that both apex locator devices did not show similar values to visual length measurements with statistically significant differences in primary teeth with root resorption (p < 0.05). For the teeth without root resorption, Endex showed similar values to visual length measurements with no statistically significant differences (p > 0.05), but Root ZX values were different than visual length and the differences were statistically significant (p < 0.05). There were no significant differences between the two apex locators considering the presence of root resorption. The two frequency apex locators can be recommended for use in root canal therapy for primary teeth with and without root resorption, only if electrical determination of root canal length is supported with other diagnostic measures.

Accuracy of the apex locating function of TCM Endo V in simulated conditions: a comparison study.

OBJECTIVE: The aim of this study was to evaluate the accuracy of the apex-locating function of the TCM Endo V and to compare the results to these of the Root ZX. STUDY DESIGN: Forty-seven extracted maxillary incisor teeth with mature apices and patent single root canals were used for the study. After the root surfaces were cleaned and access cavities were prepared, the true working lengths (TL) were determined with a #10 stainless steel file. All samples were mounted in an alginate model especially developed to test the apex locators. Both electronic apex locators were used according to the manufacturer's recommendations and adjusted to 0.5-mm accuracy to the apical foramen. EL(1) was designates as the working length measured with Root ZX and EL(2) was designated as the working length measured with TCM Endo V. A paired t test was used to statistically analyze the significance of the mean differences at the 95% confidence interval of the differences (P = .001) among TL, EL(1), and EL(2). RESULTS: There were no statistically significant differences between TL and EL(1), TL and EL(2), and EL(1) and EL(2) (P = .001). Both Root ZX and TCM Endo V gave similar results. CONCLUSIONS: TCM Endo V proved to be as reliable as Root ZX but the use of the device to determine the working length was not easy as Root ZX. Further studies are needed to compare TCM Endo V in clinical conditions with similar electric motor and apex locator combined devices.

The effect of disruption of apical constriction on periapical extrusion.

The aim of this study was to compare the amount of apical extrusion during manual instrumentation and engine-driven rotary instrumentation in teeth with disrupted apical constriction. Fifty-two teeth were divided into two groups comprising 26 teeth each. Teeth in each group were further divided into two sub-groups, the apices of which were enlarged approximately to a diameter of 0.2 mm and 0.4 mm. One group was instrumented using standardized technique with K-files and the other with ProFile .04 Taper Series 29, while irrigating with sodium hypochlorite. Glass vial model was modified for collection of extruded debris and irrigant as well as to integrate an electronic apex locator to the experimental assemble. The statistical analysis using Student's t test revealed no significant difference between instrumentation with K-files and ProFile .04 taper files (p > 0.05). There was a tendency with both techniques to extrude apically more material as the diameter of the apical patency increased.

The accuracy of three different electronic root canal measuring devices: an in vitro evaluation.

The main objective of this in vitro study was to evaluate the effects of the operator's experience level and pre-flaring on the accuracy of the results of three different brands of a new generation of root canal measuring devices, as well as the comparison among them. Extracted human teeth were prepared and then actual length and electronic length measurements were made by three different operators according to a double-blind technique. Three different operators performed electronic measurements on each specimen separately with three different electronic root canal measuring devices using in vitro models. Measurements were repeated by all operators after the pre-flaring. Taking the clinical tolerance of +/- 0.5 mm into account, there was no statistically significant difference between the accuracy of the instruments (P > 0.01). However, the results obtained from the Bingo electronic apex locator in pre-flared canals by the beginner operator were statistically significant (P < 0.01). All of the instruments had a clinically acceptable result at the tolerance of +/- 0.5 mm. If the instruments are used in accordance with the manufacturer's instructions, experience with electronic root canal measurement is not essential. However, the operator has to be more careful when working on pre-flared canals.

Interappointment emergencies in teeth with necrotic pulps.

The incidence of interappointment emergencies in symptomatic and asymptomatic teeth with necrotic pulps was evaluated, and severity of flare-ups was determined by a quantitative method using a flare-up index. There were no significant differences in the incidence of flare-ups attributable to gender, age, diameter of lesion, taking analgesics, placebos, or no medication, or preoperative symptomatic or asymptomatic tooth diagnoses (p > 0.05). There were significantly more painful flare-ups in mandibular teeth than in maxillary (p < 0.05).