Canal Aberration Assessment in Simulated Root Canals: a Comparative Study.

AIM: The aim of this study was to compare time of preparation and canal aberrations in a simulated root canals after using three different rotary systems: Endostar E5, Endostar E3 and T One File Gold. MATERIALS AND METHODS: A total of 90 endodontic training blocks were used in this study and divided into three groups consisting of 30 each (n = 30). Blocks processing was performed by thirty dentists without any prior experience in rotary instrumentation techniques. In the first group blocks were prepared using Endostar E5, in second one with Endostar E3 and in third one with T One File Gold system. The preparation time was measured. The postoperative image of each block was taken by stereomicroscope and canal aberrations (ledge and instrument fracture) was recorded. Statistical analysis was done by SPSS software. RESULTS: Instrumentation with T One File Gold system is significantly faster compared to instrumentation with Endostar E5 and Endostar E3 systems (p <0.05). There are no statistically significant differences in the type and number of procedural errors between Endostar E5, Endostar E3 and T One File Gold systems when the operators have no previous experience in rotary instrumentation techniques. CONCLUSION: Under the conditions of this study, the incidence of examined canal aberrations were similar for all tested systems. The preparation time was significantly shorter with single file system.

Ex vivo accuracy of Root ZX II, Root ZX Mini and RomiApex A-15 apex locators in extracted vital pulp teeth.

The objective of this study was to compare, ex vivo, the accuracy of three electronic apex locators (EALs), Root ZX II, Root ZX Mini and RomiApex A-15, in detecting the apical foramen (AF). Forty extracted single-Rooted human teeth with vital pulp were used in this study. After access preparation, the Root canal length of each tooth was measured by placing a #10 file until the tip was visible at the AF under a stereomicroscope. The teeth were subsequently embedded in an alginate model. In each Root canal, all three EALs were used to determine the working length, which was defined as the zero reading or equivalent. The distance between the file tip and AF was measured to an accuracy of 0.01 mm. Results were analyzed using analysis of variance and the Chi-squared test. Root ZX II, Root ZX Mini and RomiApex A-15 were accurate within 0.5 mm, 62.5, 56.2, 50% of the time. No significant differences were found between the three EALs (p > 0.05). Considering all EALs, the mean distance from the file tip to AF was 4.49 mm. The accuracy of the three EALs evaluated in this study was not statistically significantly different. The 'Apex' or '0.0' marks of the EALs do not indicate the AF itself, but just a position coronal 0.49 mm to the AF. Using a tolerance of ± 0.5 mm from the actual lengths, the ZX II yielded the most acceptable measurements.

To evaluate and compare the efficacy, cleaning ability of hand and two rotary systems in root canal retreatment.

AIM: To evaluate and compare the efficacy, cleaning ability of hand and two rotary systems in root canal retreatment. METHODOLOGY: Sixty extracted premolars were retreated with following systems: Group -ProTaper Universal retreatment files, Group 2-ProFile system, Group 3-H-file. Specimens were split longitudinally and amount of remaining gutta-percha on the canal walls was assessed using direct visual scoring with the aid of stereomicroscope. Results were statistically analyzed using ANOVA test. RESULTS: Completely clean root canal walls were not achieved with any of the techniques investigated. However, all three systems proved to be effective for gutta-percha removal. Significant difference was found between ProTaper universal retreatment file and H-file, and also between ProFile and H-file. CONCLUSION: Under the conditions of the present study, ProTaper Universal retreatment files left significantly less guttapercha and sealer than ProFile and H-file. CLINICAL SIGNIFICANCE: Rotary systems in combination with gutta-percha solvents can perform superiorly as compared to the time tested traditional hand instrumentation in root canal retreatment.

Cleaning efficiency of anatomic endodontic technology, ProFile System and Manual Instrumentation in oval-shaped root canals: an in vitro study.

AIM: This in vitro study is an attempt to compare the effectiveness in cleaning oval shaped root canals using Anatomic Endodontic Technology (AET®), ProFile system® and Manual Instrumentation with K-files. METHODOLOGY: Sixty oval shaped single rooted maxillary and mandibular premolars with straight canals were divided in to three groups. The root canals were, confirmed as being oval shape by means of radiographs made in a buccolingual and mesiodistal direction. Automated canal preparation was performed using Anatomic Endodontic Technology (group 1) and the ProFile system® (group 2). Manual instrumentation (group 3) was performed with k-files. Irrigation was performed using alternatively 3% NaOCl and 17% EDTA, followed by rinsing with normal saline. The roots were split longitudinally into two halves and examined under a scanning electron microscope. The presence of debris and smear layer was recorded at distances 1, 5 and 10 mm from the working length using a three step scoring scale. Mean scores for debris and smear layer was calculated and statistically analyzed for between and within groups significance, using the Kruskal-Wallis nonparametric ANOVA test and Bonferroni's multiple comparison test. RESULTS: At 1, 5 and 10 mm levels the root canals prepared with AET had significantly less surface debris and smear layer on the canal walls as compared to canals prepared with ProFile system® or manual instrumentation. For all three groups significantly lower mean smear layer scores (p < 0.05) were recorded at 5 and 10 mm levels compared with the 1 mm level. Significantly lower mean debris scores (p < 0.05) were also recorded at 5 and 10 mm levels for the AET group whereas no significant differences were found between the three levels for the ProFile system® and manual instrumentation groups. CONCLUSION: Although better instrumentation scores were obtained in canals prepared with AET, complete cleanliness was not achieved with any of the techniques and instruments investigated.

Impact of cooling on shaping ability of thermally treated files in canal models with double curvature.

Background: This study compared the ability of thermally treated files in shaping simulated canals with double curvature. Fifty-six canals were enlarged to a final size of 25 with ProTaper Next (PTN) or ZenFlex (ZF). Materials: Half of the samples were shaped with cooled files (n = 14 each). The amount of removed resin was measured and canal deviation was determined at eight levels. Shaping time and maximum shaping torque values were also recorded. Data were statistically analyzed using analysis of variance and LSD, Kruskal-Wallis, and chi-square tests at a 0.05 significance level. Results: Compared to PTN and cooled PTN, ZF and cooled ZF required lesser time to shape the canals. The maximum torques were found comparable between the groups. All the groups generated negligible deviations at every canal level evaluated and maintained the canal geometry. Although not significant, the cooled PTN and ZF files exhibited lesser canal deviations than their counterparts. Conclusion: All groups demonstrated similar shaping ability whilst maintaining the original curvature of the canal in simulated canals with double curvature. However, ZF groups were able to shape the canals faster than PTN groups. There was a trend that cooled files made lesser canal deviations compared to their counterparts.

Centring ability and apical transportation after overinstrumentation with ProTaper Universal and ProFile Vortex instruments.

AIM: To evaluate morphological changes to the major foramen after overinstrumentation with ProTaper Universal and ProFile Vortex Ni-Ti rotary instruments. METHODOLOGY: Twenty-eight mesiobuccal canals of maxillary and mandibular first molars were divided into two groups of 14 canals each. The root canals were prepared with ProTaper Universal or ProFile Vortex instruments. ProTaper and Vortex instruments were used until the file tip protruded 1 mm beyond the working length (0.5 mm beyond the major foramen). The major foramen was photographed before and after overinstrumentation with each file of the two systems used. The images were superimposed and evaluated using Adobe Photoshop. The parameters evaluated were canal transportation, centring ability and shape of the major foramen. Transportation and centring ability were calculated in two directions: the direction of maximum curvature (MC) and a direction vertical to the maximum curvature (VC). Measurements of canal transportation and centring ability were analysed by anova followed by post hoc least significance difference (LSD) multiple comparisons. RESULTS: No significant differences were observed amongst the different instruments with respect to centring ability in either direction (P > 0.05). The F3 ProTaper Universal instrument was associated with a higher mean values for transportation in the direction of MC (P < 0.05) than the S1, S2 and F1 ProTaper Universal instruments and the size 15, 0.06 taper, size 20, 0.06 taper, and size 25, 0.06 taper ProFile Vortex instruments. The size 30, 0.06 taper ProFile Vortex instrument had a larger mean value for transportation in the direction of MC (P < 0.05) than the S1 ProTaper Universal and size 15, 0.06 taper ProFile Vortex instruments. The S1, S2, F1, F2 and F3 ProTaper Universal files and the size 15, 0.06 taper, size 20, 0.06 taper, size 25, 0.06 taper, and size 30, 0.06 taper ProFile Vortex files produced an oval foramen in 71%, 71%, 85%, 85%, 71%, 71%, 85%, 85% and 89% of the cases, respectively. CONCLUSIONS: In most samples, the ProTaper Universal and ProFile Vortex files produced transportation of the major foramen and created an oval-shaped major foramen after overinstrumentation.

Shaping ability and cleaning effectiveness of two single-file systems in severely curved root canals of extracted teeth: Reciproc and WaveOne versus Mtwo and ProTaper.

AIM: To compare shaping ability and cleaning effectiveness of two reciprocating single-file systems with Mtwo and ProTaper rotary instruments during the preparation of curved root canals in extracted teeth. METHODOLOGY: A total of 80 root canals with curvatures ranging between 25° and 39° were divided into four groups of 20 canals. Based on radiographs taken prior to instrumentation, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared to the following apical sizes: Mtwo: size 35 using the single-length technique; ProTaper: F3, instruments were used in a modified crown-down manner; Reciproc and WaveOne: size 25. Using pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. Preparation time and instrument failures were also recorded. These data were analysed statistically using anova and Student-Newman-Keuls test. The amounts of debris and smear layer were quantified on the basis of a numerical evaluation scale and were analysed statistically using the Kruskal-Wallis test. RESULTS: During preparation no file fractured. All instruments maintained the original canal curvature well with no significant differences between the different files (P = 0.382). Instrumentation with Reciproc was significantly faster than with all other instruments (P < 0.05), while WaveOne was significantly faster than Mtwo and ProTaper (P < 0.05). For debris removal, Mtwo and Reciproc instruments achieved significantly better results (P < 0.05) than the other instruments in the apical third of the canals. In the middle and coronal parts, no significant differences were obtained between Mtwo, Reciproc and WaveOne (P > 0.05), while ProTaper showed significantly more residual debris (P < 0.05). The results for remaining smear layer were similar and not significantly different for the different parts of the canals (P > 0.05). CONCLUSIONS: Under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. The use of Mtwo and Reciproc instruments resulted in better canal cleanliness in the apical part compared with ProTaper and WaveOne.

Efficacy of two Ni-Ti systems and hand files for removing gutta-percha from root canals.

AIM: To compare the effectiveness of two Ni-Ti systems and hand files for removing gutta-percha and sealer from root canals. METHODOLOGY: The root canals of 60 single-rooted human teeth were prepared, filled with gutta-percha and sealer (Pulp Canal Sealer; SybronEndo, Orange, CA, USA). Specimens were then divided into three groups (n=20), and root filling material was removed using MTwo Retreatment Files (group 1); R-Endo (group 2); K-files and Gates-Glidden drills (group 3). After retreatment, the efficacy of each technique was assessed using radiographs that were later digitized and the images analysed using AutoCAD 2004. The percentage of residual gutta-percha was calculated for the whole canal as well as for the coronal, middle and apical thirds. Time required, apically extruded debris and the number of fractured instruments were also recorded. Data were statistically analysed using Kruskal-Wallis and Mann-Whitney U-tests. RESULTS: All instrumentation techniques left gutta-percha and sealer remnants inside the root canals. Ni-Ti systems were significantly faster (P < 0.05) than the manual technique and significantly more effective (P < 0.05) in removing gutta-percha particularly from the middle and apical thirds of the root canal. R-Endo instrumentation was significantly more effective (P < 0.05) than MTwo retreatment files in removing gutta-percha from the middle and apical thirds. R-Endo instruments were associated with the least number of cases of apical extrusion. One MTwo instrument fractured. CONCLUSIONS: The Ni-Ti systems were more effective and faster than hand files, although all techniques left gutta-percha and sealer remnants on the root canals.

Micro-CT analyses of apical enlargement and molar root canal complexity.

AIM: To compare the effectiveness of two rotary hybrid instrumentation techniques with focus on apical enlargement in molar teeth and to quantify and visualize spatial details of instrumentation efficacy in root canals of different complexity. METHODOLOGY: Maxillary and mandibular molar teeth were scanned using X-ray microcomputed tomography. Root canals were prepared using either a GT/Profile protocol or a RaCe/NiTi protocol. Variables used for evaluation were the following: distance between root canal surfaces before and after preparation (distance after preparation, DAP), percentage of root canal area remaining unprepared and increase in canal volume after preparation. Root canals were classified according to size and complexity, and consequences of unprepared portions of narrow root canals and intraradicular connections/isthmuses were included in the analyses. One- and two-way anova were used in the statistical analyses. RESULTS: No difference was found between the two techniques: DAP(apical-third) (P = 0.590), area unprepared(apical-third) (P = 0.126) and volume increase(apical-third) (P = 0.821). Unprepared root canal area became larger in relation to root canal size and complexity, irrespective of the technique used. Percentage of root canal area remaining unprepared was significantly lower in small root canals and complex systems compared to large root canals. The isthmus area per se contributed with a mean of 17.6%, and with a mean of 25.7%, when a narrow root canal remained unprepared. CONCLUSIONS: The addition of isthmuses did not significantly alter the ratio of instrumented to unprepared areas at total root canal level. Distal and palatal root canals had the highest level of unprepared area irrespective of the two instrumentation techniques examined.

Is endodontic treatment performed under general anaesthesia technically acceptable?

OBJECTIVES: Undertaking endodontic treatment under general anaesthesia (GA) is often described as difficult and hazardous, but no study reports on safe and efficacious conditions for endodontic treatment under GA. This study aims to evaluate whether compromises made for the endodontic treatment of permanent teeth under GA are acceptable. It describes the quality of endodontic treatment undertaken in two series of consecutive patients treated either under GA or local anaesthesia (LA). MATERIALS AND METHODS: Post-operative data sheets and periapical radiographs were collected for 255 permanent teeth treated under GA during a 4-year period (GA group, 125 patients with special needs) and for 246 permanent teeth treated under local anaesthesia over 7 months (LA group, 180 healthy patients). The radiographic criteria for quality of endodontic treatment (RCQET) were considered satisfactory when (1) the root filling was within 2 mm of the apex; (2) the filling displayed no voids or defects; and (3) all the visible canals had been obturated. The type of tooth, pulpal status and periapical status were considered independent variables for RCQET. RESULTS: The proportion of satisfactory RCQET reached 63% in both groups and differed by type of tooth, being significantly lower for molars than for other teeth. CONCLUSION: From a technical point of view, compromises made for the endodontic treatment of permanent teeth under GA are acceptable. Further studies should be conducted to evaluate the long-term success of endodontic treatment performed under GA. CLINICAL RELEVANCE: This study supports the feasibility of endodontic treatment for patients treated under GA.

The association between complete absence of post-treatment periapical lesion and quality of root canal filling.

AIM: The technical quality of a root canal treatment is clinically judged by the apical extension and homogeneity of the filling material imaged by periapical radiographs (PA). The aim of this experiment was to evaluate the association between the technical quality of the root canal filling and treatment outcome. MATERIALS AND METHODS: In 234 teeth (268 roots) that underwent root-canal treatment, the quality of the root canal filling as well as the outcome of the treatment were assessed with both PA and cone-beam computed tomography (CBCT) 2 years after treatment. Satisfactory root filling on PA was defined as 0-2 mm within the radiographic apex without voids; on CBCT scans, the apical end of the canal replaced the radiographic apex. The outcome predictors were analyzed using multivariate logistic regression. RESULTS: At recall, periapical radiolucent areas were absent in 198 (74%) roots on PA and 164 (61%) roots on CBCT scans. The presence of preoperative periapical radiolucency and the quality of root filling and coronal restoration were identified by both PA and CBCT as outcome predictors (p < 0.01). Complete absence of post-treatment periapical radiolucency was observed in CBCT scans in 81% and 49% of satisfactory and unsatisfactory root fillings, respectively, as compared to 87% and 61% revealed by PA. CONCLUSION: Satisfactory root fillings were associated with a favorable outcome, confirmed by both PA and CBCT. CLINICAL RELEVANCE: The outcome of root canal treatment is improved once the filling is 0-2 mm from the apex, and no voids could be detected. Technical skills and performance of root canal filling procedures should be emphasized, and suitable methods should be developed in order to achieve more compacted filling materials without voids and at the correct length.

Impact of nickel-titanium instrumentation of the root canal on clinical outcomes: a focused review.

Nickel-titanium (NiTi) root canal instruments have improved the technical quality of enlarging and shaping. These instruments have been shown to prepare even severely curved root canal with fewer procedural errors than traditional stainless steel hand instruments. While it would appear that these instruments might enhance clinical outcomes, very few studies have assessed their impact when used in primary root canal treatment. Clinical studies investigating the outcome of primary root canal treatment using nickel-titanium hand or rotary instruments were identified (MEDLINE database) using appropriate key words in an attempt to determine if there have been enhanced outcomes with these instruments. Evidence from one clinical trial suggests that (i) better maintenance of the original canal curvature and shape results in increased success rates and (ii) that ledging of root canals results in reduced success rates. Evidence from two studies indicates that the use of NiTi-either hand or rotary-instruments significantly increases success rates of primary nonsurgical root canal treatment compared with the use of stainless steel hand instruments, while three investigations failed to show any significant differences.

Technical quality of root canal fillings done in a Nigerian general dental clinic.

BACKGROUND: Previous reports indicate that worldwide, the technical quality of root canal fillings is poor. There are few reports from sub-Saharan Africa and none yet from Nigeria where most patients access treatment from non-specialists especially at general dental clinics. The aim of this study was to evaluate the technical quality of root canal fillings done in a general dental clinic with emphasis on the effects of professional experience of the operator, whether tooth was anterior or posterior and whether it was a maxillary or mandibular tooth. METHODS: Retrospective study of case notes and periapical radiographs of patients with completed root canal fillings seen between 2008 and 2011. Inclusion criteria included cases of primary treatment with available case notes, good quality pre-operative and post-operative periapical radiographs. Technical quality that was assessed was root canal length and homogeneity. Root canal fillings were classified either as Good Quality Endodontic Work (GQEW) or Non- Good Quality Endodontic Work (NGQEW). RESULTS: Fifty-one patients aged between 8 and 54 years (mean 28) fulfilled the inclusion criteria for this study. From these, there were 62 root filled teeth giving a ratio of 1.2 root canal filled teeth per person. There were acceptable length of root canal fillings in 71% of teeth, 58.1% were homogeneous while 53.2% were GQEW. There was no statistically significant difference in whether tooth was root filled by junior or senior dentist (p=0.43), anterior or posterior (p=0.11). There was significant association between GQEW and maxillary teeth (p=0.03). CONCLUSION: This study showed that the overall technical quality of root canal fillings done by non-specialists was better than earlier reports but lower than that done by endodontists. Since many patients receive treatment from non-specialists in developing countries, it is necessary to improve technical quality of root canal fillings done in general dental clinics. These could be through improvement in the quality of undergraduate training and more post graduate continuing education courses for skills update.

K-file vs ProFiles in cleaning capacity and instrumentation time in primary molar root canals: an in vitro study.

OBJECTIVES: This study compares the efficiency of manual K-files and rotary ProFiles in cleaning capacity and instrumentation time in primary molar root canals. MATERIALS AND METHODS: Seventy-five maxillary and mandibular primary molar root canals were instrumented with ProFiles and K-files in the step-back manner from size #10 to #40. The teeth were decalcified, dehydrated and cleared, and analyzed for the presence of dye remaining on the root canal walls, which served as an evidence of cleaning capacity of both the techniques. RESULTS: The results showed a significant difference in the cleaning capacity of the root canals with ProFiles and K-files, in apical and coronal thirds of the root canal. ProFiles have been found to be more efficient in cleaning the coronal thirds and K-files in cleaning apical thirds of the root canals. Both the techniques were almost equally effective in cleaning the middle thirds of the canals. The time taken during the cleaning of the root canals appeared to be statistically shorter with K-files than profiles.

The taper of cast post preparation measured using innovative image processing technique.

BACKGROUND: No documentation in the literature about taper of cast posts. This study was conducted to measure the degree of cast posts taper, and to evaluate its suitability based on the anatomy aspects of the common candidate teeth for post reconstruction. METHODS: Working casts for cast posts, prepared using Gates Glidden drills, were collected. Impressions of post spaces were made using polyvinyl siloxan putty/wash technique. Digital camera with a 10' high quality lens was used for capturing two digital images for each impression; one in the Facio-Lingual (FL) and the other in the Mesio-Distal (MD) directions. Automated image processing program was developed to measure the degree of canal taper. Data were analyzed using Statistical Package for Social Sciences software and One way Analysis of Variance. RESULTS: Eighty four dies for cast posts were collected: 16 for each maxillary anterior teeth subgroup, and 18 for each maxillary and mandibular premolar subgroup. Mean of total taper for all preparations was 10.7 degree. There were no statistical differences among the total taper of all groups (P = .256) or between the MD and FL taper for each subgroup. Mean FL taper for the maxillary first premolars was lower significantly (P = .003) than the maxillary FL taper of the second premolars. FL taper was higher than the MD taper in all teeth except the maxillary first premolars. CONCLUSIONS: Taper produced did not reflect the differences among the anatomy of teeth. While this technique deemed satisfactory in the maxillary anterior teeth, the same could not be said for the maxillary first premolars. Careful attention to the root anatomy is mandatory.

Current Trends in the Use of Irrigant Activation Techniques Among Endodontists & Post-Graduate Dental Students in India -A Knowledge, Attitude and Practice Based Survey.

Objective: The aim of this survey was to examine the practice/use of Irrigant Activation Techniques (IAT) among Endodontists and post-graduate dental students in India. Methods: An invitation to participate in this survey was sent by electronic mail to 902 members of Indian Endodontic society. A total of 32 questions were finalized for the survey after validation by five endodontic experts. Survey contained 2 demographic questions, 7 knowledge based questions, 11 questions on attitude and 12 questions on practice of IAT. The reliability was checked by randomly asking 10 participants to fill the survey forms again after 15 days. The data was analyzed using chi-square test (P<0.05). Results: The overall response rate for the survey was 30.5%. The content validity ratio for the questionnaire was 0.972 & the reliability calculated using Kappa scores was 0.978. Most of the respondents (87.3%) use IAT, while 4.7% do not use IAT. Most commonly used IAT was Manual dynamic agitation (MDA) used by 28.7%, followed by Ultrasonics in 17.2%. Sonic & negative pressure (EndoVac) was used by less than 10% of respondents. Combination of IAT was used by 39%. In 23 (5 on knowledge, 9 on attitude & 9 on practice) out of the 32 questions in this survey, there was a statistically significant difference (P<0.05) in the answers between the groups, with post-graduate dental students opting the correct choices. Sodium hypochlorite (NaOCl) is the preferred choice of irrigant for IAT according to 48.6%, Chlorhexidine (CHX) is used by 4.2% & Ethylene diamine tetra acetic acid (EDTA) by 2.4%. Combination of two irrigants is used by 28.7% and 6% use all the three irrigants. Conclusion: Vast majority of the Endodontist in India use some form of IAT to improve the efficacy of irrigation. MDA is the most commonly used IAT.

Efficacy of reciprocating systems for removing root filling material plus complementary cleaning methods in flattened canals: Microtomography and scanning electron microscopy study.

The aim of this study was to evaluate three reciprocating systems and complementary cleaning methods on filling material removal during retreatment of flattened canals. Thirty-six mandibular incisors were prepared using rotary instruments up to size 25.08 and filled using the single-cone technique. Subsequently, the teeth were divided into three groups (n = 12) according to retreatment procedures: Reciproc Blue (RB): 25/0.08 and 40/0.06; ProDesign R (PDR): 25/0.06 and 35/0.05; and WaveOne Gold (WOG): 25/0.07 and 35/0.06. The remaining filling volume materials were assessed by means of micro-CT imaging before and after retreatment. After this, the specimens were subdivided into three groups according to complementary cleaning methods: XP-Endo Shaper (30/0.01); passive ultrasonic irrigation (PUI); 60° oscillatory instrumentation with #30 H-file, and micro-CT scan was taken. Then, the roots were cut in half and the samples were analyzed by scanning electron microscope (SEM). The data were analyzed statistically using Kruskal-Wallis and Dunn's Multiple Comparison test with significance level of 5%. None of the reciprocating files promoted complete removal of filling material and there was no statistical difference between the groups, regardless instrument size (p > 0.05). Complementary cleaning methods increased remnant filling removal (p < 0.05). XP-endo Shaper significantly reduced the amount of filling material in the apical and middle thirds, compared with H-files (p < 0.05), with no difference with PUI. In the SEM, there was no statistical difference among the instruments (p > 0.05). The reciprocating systems showed similar effectiveness in removing root filling material. Complementary cleaning method with the XP-Shaper enhanced filling material removal.

Treatment outcome in endodontics: the Toronto study--phases 3 and 4: orthograde retreatment.

Outcome 4-6 years after retreatment was assessed for Phases 3 and 4 of the Toronto Study. Of 477 teeth retreated, 333 were lost to follow-up, 18 were extracted, and 126 (41% recall, excluding 124 discontinuers) were examined for outcome of healed (periapical index score, < or = 2; no signs or symptoms) or diseased. When pooled with Phases 1 and 2, 187 of 229 teeth (82%) were healed. Logistic regression identified significant (P < or = .05) preoperative outcome predictors: root filling quality (odds ratio [OR], 4.18; confidence interval [CI], 1.72-10.12; healed: inadequate, 88%; adequate, 66%), perforation (OR, 4.01; CI, 1.28-12.62; healed: absent, 87%; present, 56%), and radiolucency (OR, 3.33; CI, 1.19-9.36; healed: absent, 93%; present, 80%). In teeth with radiolucency, outcome predictors were number of treatment sessions (OR, 12.08; CI, 1.84-infinity; healed: one, 100%; > or = 2, 77%) and previous root filling quality (OR, 7.68; CI, 2.36-26.89; healed: inadequate, 86%; adequate, 50%). Outcome was better in teeth with inadequate previous root filling, without perforation and radiolucency. Suggested significance of number of treatment sessions in teeth with radiolucency requires validation from randomized controlled trials.