A Novel Technique for Identification of Wear Values at Different Lengths after Multiple Clinical Use of Different File Systems.

Introduction The purpose of this research is to assess the wearing of the rotary file system (Protaper Next) and reciprocating file systems (Reciproc Blue and WaveOne Gold) at different lengths using a novel technique after in vivo clinical use. Materials and Methods Twelve different unused samples from each brand were accepted as reference values. For three different brands, the diameters of the files were measured by taking 12 samples used once, 12 samples used twice, and 12 samples used three times. Images were taken with a USB Micron Microscope, and file diameters were measured by determining limit values with Autocad. Result Reciproc Blue system was the most worn at apical 1 mm, and WaveOne Gold system was the most worn at apical 3 mm. PTN system exhibited the least wearing at any length. Moreover, less wearing was observed in the rotation motion than in the reciprocating motion. Conclusion In clinical practice, for the guttapercha to be fully adapted to the apical construction prepared according to the determined WL, the file should not undergo any wearing and volume reduction. Wearing-especially in the apical parts of the file-causes less preparation, and this situation could lead to apically obturation failure.

Nonsurgical management of type II dens invaginatus with cone beam computed tomography: A rare case.

Dens invaginatus is a progressive abnormality resulting from invagination of the crown or root before calcification. This case report presents nonsurgical endodontic treatment and nine-year follow-up results of a right maxillary canine tooth with type II dens invaginatus. A 40-year-old female patient was referred to the clinic for treatment of her maxillary right canine tooth. The invagination was managed on a two-visit appointment. On the first visit, the invagination area, which was disconnected, was completely removed from the root canal. The invagination area was instrumented, and the root canal was dressed with calcium hydroxide. At the second appointment, apexification was done using mineral trioxide aggregate compacted to the apical 3mm. Finally, the invaginated area and the root canal were obturated with a warm vertical compaction technique. At a nine-year follow-up, the invaginated tooth was asymptomatic, and the periradicular lesion showed satisfactory healing radiographically.

Effect of Mineral Trioxide Aggregate Apical Plug Thickness on Fracture Resistance of Immature Teeth.

INTRODUCTION: The aim of this study was to compare the fracture resistance of simulated immature teeth after using different thicknesses of mineral trioxide aggregate (MTA) apical plugs. METHODS: Fifty-two human maxillary anterior teeth were used. Five teeth were the positive control group; they were prepared using Peeso reamers to simulate immature teeth without any access cavity preparation. Access cavities of the 47 teeth were prepared, and the canals were instrumented with Peeso reamers. Five teeth served as the negative control; they were filled with calcium hydroxide. Forty-two teeth were divided into 3 groups; in groups 1, 2, and 3, MTA was placed into canals as a 3-mm and a 6-mm apical plug and a thorough canal length, respectively. The rest of the canals in groups 1 and 2 were filled with gutta-percha and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany). After the storage period, the roots were covered with a polyether impression material and were embedded into self-curing resin blocks. Each specimen was then subjected to fracture testing using a universal testing machine. Data were analyzed using 1-way analysis of variance with the Tukey post hoc test for multiple comparisons. RESULTS: The negative group showed the lowest fracture resistance compared with the other groups. The 3-mm apical plug group showed the highest fracture resistance (P < .05). No significant differences were found between the 3-mm and 6-mm apical plug groups (P > .05). CONCLUSIONS: MTA should be used as an apical plug instead of root canal filling material to increase the fracture resistance of immature teeth.

Effect of retreatment instruments on microcrack formation: a microcomputed tomography study.

INTRODUCTION: The purpose of this study was to compare the occurrence of microcracks in teeth prepared with different retreatment systems using microcomputed tomography (micro-CT). METHODS: Forty-two freshly extracted mandibular premolar teeth were used. The root canals were instrumented with stainless steel K-files to an apical size of 35/.02 using the balanced-force technique and were obturated using the passive compaction technique. The specimens were divided into 3 experimental groups according to retreatment system used (n = 14): ProTaper Universal retreatment (PTUR), Mtwo retreatment (MTR), or D-RaCe retreatment (D-RC) systems. Each specimen was scanned using a high-resolution micro-CT system before instrumentation, after obturation, and after the removal of the filling material. The images were evaluated, and the presence of microcracks was recorded. RESULTS: The PTUR system demonstrated the highest percentage, while MTR and D-RC retreatment systems resulted in similar numbers of microcracks. CONCLUSIONS: Clinicians should be aware that all retreatment systems may cause microcracks.

Postoperative pain intensity after using different instrumentation techniques: a randomized clinical study.

OBJECTIVES: The aim of this clinical study was to evaluate the influence of the instrumentation techniques on the incidence and intensity of postoperative pain in single-visit root canal treatment. MATERIAL AND METHODS: Ninety patients with single root/canal and non-vital pulps were included. The patients were assigned into 3 groups according to root canal instrumentation technique used; modified step-back, reciprocal, and rotational techniques. Root canal treatment was carried out in a single visit and the severity of postoperative pain was assessed via 4-point pain intensity scale. All the participants were called through the phone at 12, 24 and 48 h to obtain the pain scores. Data were analyzed through the Kruskal-Wallis test. RESULTS: There was significant difference between all groups (p<0.05). The modified step-back technique produced postoperative pain significantly lower than the rotational (p=0.018) and reciprocal (p=0.020) techniques. No difference was found between the reciprocal and rotational techniques (p=0.868). Postoperative pain in the first 12 h period (p=0.763) and in the 24 h period (p=0.147) was not significantly different between the groups. However, the difference in the 48 h period was statistically different between the groups (p=0.040). CONCLUSION: All instrumentation techniques caused postoperative pain. The modified step-back technique produced less pain compared to the rotational and reciprocal techniques.

Postoperative pain intensity after using different instrumentation techniques: a randomized clinical study

Abstract Postoperative pain is a frequent complication associated with root canal treatment, especially during apical instrumentation of tooth with preexisting periradicular inflammation Objectives The aim of this clinical study was to evaluate the influence of the instrumentation techniques on the incidence and intensity of postoperative pain in single-visit root canal treatment. Material and Methods Ninety patients with single root/canal and non-vital pulps were included. The patients were assigned into 3 groups according to root canal instrumentation technique used; modified step-back, reciprocal, and rotational techniques. Root canal treatment was carried out in a single visit and the severity of postoperative pain was assessed via 4-point pain intensity scale. All the participants were called through the phone at 12, 24 and 48 h to obtain the pain scores. Data were analyzed through the Kruskal–Wallis test. Results There was significant difference between all groups (p<0.05). The modified step-back technique produced postoperative pain significantly lower than the rotational (p=0.018) and reciprocal (p=0.020) techniques. No difference was found between the reciprocal and rotational techniques (p=0.868). Postoperative pain in the first 12 h period (p=0.763) and in the 24 h period (p=0.147) was not significantly different between the groups. However, the difference in the 48 h period was statistically different between the groups (p=0.040). Conclusion All instrumentation techniques caused postoperative pain. The modified step-back technique produced less pain compared to the rotational and reciprocal techniques.

Influence of passive ultrasonic irrigation on the efficiency of various irrigation solutions in removing smear layer: a scanning electron microscope study.

To evaluate the influence of passive ultrasonic irrigation (PUI) to remove the smear layer with different irrigation solutions. Seventy-eight single rooted mandibular premolars were used. The working lengths were measured and the root canals were prepared by using nickel titanium rotary files. The specimens were subjected to six different irrigation regimens: sodium hypochloride (NaOCl) with classic irrigation (CI); NaOCl with PUI; EDTA with CI; EDTA with PUI; QMix with CI; and QMix with PUI. The specimens were split longitudinally. Scanning electron microscopy images were taken to evaluate the amount of residual smear layer and scored. Statistical analysis was performed with the Kruskal-Wallis test. The Dunn's test was used for post hoc testing after the Kruskal-Wallis test. The smear layer scores of apical thirds were significantly higher than coronal and middle thirds except for NaOCl + CI group (p < 0.001). The irrigation with PUI improved the efficacy of all irrigation solutions on removal of smear layer in both coronal and middle thirds (p < 0.001). The PUI activation increased the activity of NaOCl, EDTA, and QMix, respectively without any significance. All irrigation regimens were significantly more effective in coronal and middle thirds compared to apical third. PUI significantly increased the efficacy of smear layer removal regardless of irrigation solution.

Apical transportation during removal of root canal filling with different retreatment systems.

INTRODUCTION: This study aimed to compare apical transportation during retreatment using ProTaper Universal retreatment (PTUR), Mtwo R and D-RaCe instruments in curved root canals. METHODS: 36 extracted mandibular molar teeth with curved mesiobuccal roots were selected. The teeth were embedded into acrylic blocks. The blocks were fixed on the experimental setup. After determining the working length (WL), mesiobuccal canals were prepared with ProTaper Universal rotary instruments to size F1 (20/0.06). After the obturation, the teeth were randomly divided into groups; the PTUR files were used as D1 (30/0.09) for coronal third and D2 (25/0.08) at WL. Mtwo R files, R1 (15/0.05) and R2 (25/0.05) were used at WL. D-RaCe files were used as DR1 (30/.10) in cervical third and DR2 (25/0.04) at WL. Image J analysis software was used to measure the apical transportation. Differences between the 3 groups were analyzed with a 1-way ANOVA or Kruskal-Wallis tests. RESULTS: There was no significant difference between groups in the apical transportation in either the mesiodistal (p = 0.166) or buccolingual (p = 0.518) direction. Among the 3 groups, the apical transportation was the greatest in the D-RaCe group. CONCLUSIONS: It can be concluded that all retreatment systems caused a similar level of apical transportation.

Comparison of the amount of apical debris extrusion associated with different retreatment systems and supplementary file application during retreatment process.

BACKGROUND: The type of instrument affects the amount of debris extruded. The aim of this study was to compare the effect of retreatment systems and supplementary file application on the amount of apical debris extrusion. MATERIALS AND METHODS: Forty-eight extracted mandibular premolars with a single canal and similar length were selected. The root canals were prepared with the ProTaper Universal system with a torque-controlled engine. The root canals were dried and were obturated using Gutta-percha and sealer. The specimens were randomly divided into four equal groups according to the retreatment procedures (Group 1, Mtwo retreatment files; Group 2, Mtwo retreatment files + Mtwo rotary file #30 supplementary file; Group 3, ProTaper Universal retreatment (PTUR) files; and Group 4, PTUR files + ProTaper F3 supplementary file). The extruded debris during instrumentation were collected into preweighed Eppendorf tubes. The amount of apically extruded debris was calculated by subtracting the initial weight of the tube from the final weight. Three consecutive weights were obtained for each tube. RESULTS: No statistically significant difference was found in the amount of apically extruded debris between Groups 1 and 3 (P = 0.590). A significant difference was observed between Groups 1 and 2 (P < 0.05), and between Groups 3 and 4 (P < 0.05). CONCLUSIONS: The use of supplementary file significantly increased the amount of apically extruded debris.

Comparison of treatment choices among endodontists, postgraduate students, undergraduate students and general dentists for endodontically treated teeth.

OBJECTIVES: To compare the decision-making choices among Turkish dentists with different educational backgrounds. METHODS: Eighty endodontically treated teeth were selected from the authors' private archives and placed into four case groups of equal size: case-group 1, symptom/periapical lesion (n = 20); case-group 2, symptom/no periapical lesion (n = 20); case-group 3, no symptom/periapical lesion (n = 20); and case-group 4, no symptom/no periapical lesion (n = 20). The respective periapical radiograph of each tooth was scanned and, together with a leaflet containing relevant information, was distributed to the participants. Participants comprised undergraduate students (n = 20), general dentists (n = 20), endodontic postgraduate students (n = 20) and endodontists (n = 20). Each participant was requested to choose only one option, from five previously determined treatment alternatives, for each tooth: no treatment, wait and see; non-surgical root canal treatment; only apical surgery (apical resection and retrofilling or only apical curettage); retreatment and apical surgery; or extraction. The results were expressed as frequency and percentage. Kendall's W test was used to determine the differences among the participant groups. RESULTS: There was a statistically significant difference among the practitioners in the preferred treatment options for different case-groups (P < 0.05). For case-groups 1, 2 and 3, the postgraduate students and endodontists preferred non-surgical retreatment more frequently than did the undergraduate students and general dentists. However, in case-group 4, all participants suggested the first treatment option, 'no treatment, wait and see' more frequently than the other treatment options. CONCLUSIONS: Within the limitations of this survey study it was concluded that endodontists and graduate programme students tend more towards conservative treatment (retreatment) compared with general dentists and undergraduate students.

Comparison of apically extruded debris associated with several nickel-titanium systems after determining working length by apex locator.

BACKGROUND/AIM: To compare apically extruded debris using ProTaper Universal (PTU), ProTaper Next (PTN), WaveOne (WO), Twisted File (TF), M-Two (MT), and Revo-S (RS) after determining the working length (WL) with root ZX. MATERIALS AND METHODS: Seventy-two teeth were selected. The WL determination was performed with root ZX. The teeth were divided into six experimental groups, randomly. In groups, root canals were prepared with PTU to size F4/0.06, with PTN to size X4/0.06, with WO to size 40/0.08, with TF to size 40/0.04, with MT to size 40/0.06, and with RS to size AS40/0.06. After preparations were completed, final irrigation was performed with 2 mL distilled water, and a total of 10 mL of distilled water was used in each tooth. Tubes were stored in an incubator at 68°C for 5 days to evaporate the distilled water before weighing the dry debris. Data were analyzed by the Mann-Whitney U-test. RESULTS: The RS group led to the highest amount of extruded debris, however, WO led to the least amount of extruded debris. There was no statistically difference among the groups (P > 0.05). CONCLUSIONS: The authors conclude that the results obtained might depend on the apex locator used to determine the WL.

Comparing the Effect of Different Voxel Resolutions for Assessment of Vertical Root Fracture of Permanent Teeth.

BACKGROUND: The teeth with undiagnosed vertical root fractures (VRFs) are likely to receive endodontic treatment or retreatment, leading to frustration and inappropriate endodontic therapies. Moreover, many cases of VRFs cannot be diagnosed definitively until the extraction of tooth. OBJECTIVES: This study aimed to assess the use of different voxel resolutions of two different cone beam computerized tomography (CBCT) units in the detection VRFs in vitro. MATERIALS AND METHODS: The study material comprised 74 extracted human mandibular single rooted premolar teeth without root fractures that had not undergone any root-canal treatment. Images were obtained by two different CBCT units. Four image sets were obtained as follows: 1) 3D Accuitomo 170, 4 × 4 cm field of view (FOV) (0.080 mm(3)); 2) 3D Accuitomo 170. 6 × 6 cm FOV (0.125 mm(3)); 3) NewTom 3G, 6˝ (0.16 mm(3)) and 4) NewTom 3G, 9˝ FOV (0.25 mm(3)). Kappa coefficients were calculated to assess both intra- and inter-observer agreements for each image set. RESULTS: No significant differences were found among observers or voxel sizes, with high average Z (Az) results being reported for all groups. Both intra- and inter-observer agreement values were relatively better for 3D Accuitomo 170 images than the images from NewTom 3G. The highest Az and kappa values were obtained with 3D Accuitomo 170, 4 × 4 cm FOV (0.080 mm(3)) images. CONCLUSION: No significant differences were found among observers or voxel sizes, with high Az results reported for all groups.

Influence of diode laser application on the efficiency of QMiX and EDTA solutions in removing smear layer.

OBJECTIVE: The aim of this study was to compare the efficacy of QMiX and ethylenediaminetetraacetic acid (EDTA) solutions with diode laser treatment in smear layer removal. BACKGROUND DATA: Removing the smear layer from the apical thirds of root canals is difficult, regardless of the solution used. Researchers have been improved some irrigation agitation methods to overcome this challenge, and agitation of irrigants with laser devices has become popular. METHODS: Seventy-five extracted mandibular premolars were used. After root canals were, prepared the specimens were divided into five groups (n = 15): Group 1, no irrigation; Group 2, 17% EDTA; Group 3, QMiX solution; Group 4, 17% EDTA with diode laser; and Group 5, QMiX with diode laser. The roots were split longitudinally and prepared for scanning electron microscopic (SEM) investigation. The smear layer was evaluated under × 500, × 1000, and × 2000 magnifications. RESULTS: The amount of smear layer was found significantly high in the control group (p < 0.001). In the EDTA group, the amount of smear layer was significantly high at the apical thirds, and the differences among the three regions were statistically significant (p < 0.001). In the QMiX group, no difference was found between the coronal and middle thirds; however, the amount of smear layer was significantly high at the apical thirds (p < 0.001). In the EDTA plus laser and the QMiX plus laser groups, the smear layer was found significantly high at the apical thirds (p < 0.001). However, no differences were found between the coronal and middle thirds in either group. CONCLUSIONS: None of the solutions completely removed the smear layer, especially at the apical thirds. Diode laser treatment with solutions decreased the amount of smear layer, without significance.

Power Hydrogen Evaluation of Apexification Materials: EndoCal 10, Mineral Trioxide Aggregate and Calasept Plus.

AIM: The present study was to evaluate pH values of apexification materials. MATERIALS AND METHODS: The materials were placed in 1 cm long and 4 mm diameter tubes. After sample immersion, glass flasks were hermetically sealed with rubber caps to attenuate any effects of external environmental factors and maintained at 37°C. The power hydrogen of the pastes was measured 1 hour, 3 hours, 8 hours, 24 hours, 72 hours and 7 days after preparation. pH was calibrated with solutions of known pH (7.0). Mann-Whitney test were used to determine significant differences. RESULTS: The mean pH of all medications was < 12.0 throughout the experiment. At 24 hours, EndoCal 10 had the highest pH of all the materials (p < 0.05). CONCLUSION: According to the results obtained, it may be concluded that calcium oxide (EndoCal 10) presented the highest pH compared with mineral trioxide aggregate (MTA) and Calasept Plus [Ca(OH)2]. CLINICAL SIGNIFICANCE: Apexification is an important treatment in immature teeth. For this reason, used materials in apexification should have some properties, such as high pH and stimulating to be hard tissue. Therefore, the material should be chosen carefully in apexification of immature teeth.

Comparison of the Resistance of Teeth Instrumented with Different Nickel-Titanium Systems to Vertical Root Fracture: An In Vitro Study.

INTRODUCTION: This study compared the fracture resistance of teeth instrumented with ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Next (PTN, Dentsply Maillefer), WaveOne (Dentsply Maillefer), Twisted File (SybronEndo, Orange, CA), Mtwo (MT; VDW, München, Germany), and Revo-S (MicroMega, Besançon, France) nickel-titanium systems and obturated with compatible gutta-percha cones of finishing files using the single-cone technique and a resin sealer. METHODS: The study included 72 mandibular premolar teeth. The roots were covered with additive silicone and placed in Eppendorf tubes, which were filled with a self-curing acrylic. The tubes were separated into 6 groups: prepared with the ProTaper Universal (F4 40/.06) (group 1), prepared with the PTN (X4 40/.06) (group 2), prepared with the WaveOne reciprocating file (40/.08) (group 3), prepared with the Twisted File (40/.04) (group 4), prepared with the MT (40/.06) (group 5), and prepared with the Revo-S (AS 40/.06) (group 6). After the preparations were completed, all the teeth were filled with the appropriate gutta-percha systems. The force (N) was applied at a 1-mm/min crosshead speed until the roots fractured. Differences among the groups were analyzed by Tukey and analysis of variance tests. RESULTS: Group 2 was the most resistant to fracture, and group 5 was the least resistant. The difference in the fracture resistance between the 2 groups was statistically significant (P = .019). The resistance of group 3 and group 6 to vertical root fracture was similar, and the resistance of group 4 was slightly lower than that of the other groups (P = .058). CONCLUSIONS: The roots instrumented with the MT were the least resistant, and the roots instrumented with the PTN were the most resistant to VRF.

The effect of the temperature changes of EDTA and MTAD on the removal of the smear layer: a scanning electron microscopy study.

The purpose of this study was to determine the effectiveness of EDTA and MTAD at different temperatures as a final irrigant to remove the smear layer after the use of 5.25% NaOCl. Seventy-eight human mandibular premolars with single straight canal were prepared by a crown-down technique using rotary 0.06 taper nickel-titanium files. Final irrigation was performed with EDTA and MTAD at different temperatures. The removal of the smear layer in the coronal, middle and apical level of each canal was examined under scanning electron microscope. No difference was found between the EDTA and MTAD at 4°C, 25°C, and 37°C temperatures regardless of the canal level (coronal, middle and apical) (P = 0.286). In EDTA-25, EDTA-37, MTAD-25, and MTAD-37 groups, the difference among the coronal, middle, and apical levels were statistically no significant (P > 0.05). Our findings showed that EDTA and MTAD at 25°C and 37°C are more effective than EDTA and MTAD at 4°C even in the apical level.

Intraradicular splinting with endodontic instrument of horizontal root fracture.

Introduction. Root fractures, defined as fractures involving dentine, cementum, and pulpal and supportive tissues, constitute only 0.5-7% of all dental injuries. Horizontal root fractures are commonly observed in the maxillary anterior region and 75% of these fractures occur in the maxillary central incisors. Methods. A 14-year-old female patient was referred to our clinic three days after a traffic accident. In radiographic examination, the right maxillary central incisor was fractured horizontally in apical thirds. Initially, following local infiltrative anesthetics, the coronal fragment was repositioned and this was radiographically confirmed. Then the stabilization splint was applied and remained for three months. After three weeks, according to the results of the vitality tests, the right and left central incisors were nonvital. For the right central incisor, both the coronal and apical fragments were involved in the endodontic preparation. Results. For the right central tooth, both the coronal and apical root fragments were endodontically treated and obturated at a single visit with white mineral trioxide aggregate whilst the fragments were stabilized internally by insertion of a size 40 Hedstrom stainless-steel endodontic file into the canal. Conclusion. Four-year follow-up examination revealed satisfactory clinical and radiographic findings with hard tissue repair of the fracture line.

Evaluation of microcrack formation in root canals after instrumentation with different NiTi rotary file systems: a scanning electron microscopy study.

The aim of this study was to evaluate the dentinal microcrack formation of ProTaper Universal, ProTaper Next, and WaveOne. Sixty extracted mandibular molars were selected. The mesial roots were resected and randomly divided into four groups (n = 15). The canals were prepared with hand files (group 1), ProTaper Universal (group 2), ProTaper Next (group 3), and WaveOne (group 4) instrument systems. The roots were separated horizontally at 3, 6, and 9 mm from the apex. Digital images were captured at ×40 magnification using scanning electron microscopy to detect microcrack formation. Statistical analysis was performed by Pearson Chi-square test. The prevalence of microcracks in group 2, group 3, and group 4 were significantly higher when compared to group 1 (p < 0.001). Group 2, group 3, and group 4 demonstrated similar prevalence of microcracks without significant difference (p > 0.05) in all sections. All instruments caused microcracks except for hand file. The highest percentage of microcrack was recorded in 3 mm section for all groups.

Age and sex-related differences of pulp chamber size in mandibular second molars.

AIM: The aim of this study was to compare the size of the pulp chamber in mandibular second molars with the gender and age by means of panoromic radiographs. MATERIALS AND METHODS: In this study, 200 panoromic radiographs of patients were randomly selected from the archives of the Faculty of Dentistry of Ondokuz Mayis University. The radiographs of the patients were measured under a stereomicroscope and categorized according to the gender and age. RESULTS: Statistically differences were found in the mean sizes of pulp chamber between the groups under and above the age of 30 years (P < 0.05). There were significant differences in terms of "the distance between the tip of the lingual cusp to the roof of the pulp chamber", "the distance between the tip of the lingual cusp to the floor of the pulp chamber" and "the distance from the tip of the lingual cusp to the closest point of the furcation" between the male and female genders (P < 0.05). CONCLUSION: It is concluded that the pulp chamber can be exposed easily in female patients, because it is less shallow than males. However, the size of pulp chamber reduces after the age of 30 years in both the genders.