Extrusion of debris during retreatment using various nickel-titanium files in teeth with simulated lateral root perforation.

PURPOSE: To investigate the influence of various nickel-titanium (Ni-Ti) files on debris extrusion during the retreatment of teeth with simulated lateral root perforation, focusing on root resorption. METHODS: Sixty human mandibular premolar teeth were divided into groups with and without perforation and further subdivided based on the retreatment technique. Lateral root perforations were created in one group (Group 1), while the other group had no perforations (Group 2). Two retreatment techniques were compared: Remover (RE)+One RECI (OR) and ProTaper Universal Retreatment (PTUR)+WaveOne Gold (WOG). The weight of the extruded debris was determined. The time of both retreatment procedures was measured. Statistical analyses were performed using a two-way analysis of variance (ANOVA) test (P < 0.05). RESULTS: Teeth with simulated lateral root perforation exhibited higher extrusion of debris during retreatment. In both groups, RE+OR files led to more extruded debris than PTUR+WOG files. However, this difference was statistically significant in Group 2 (P < 0.001). Compared to PTUR+WOG files, RE+OR files showed a statistically significant longer time to remove obturation material (P < 0.001). CONCLUSION: Perforated teeth exhibited significantly higher debris extrusion. While both file systems demonstrated similar debris extrusion in perforated teeth, the RE+OR files significantly increased debris extrusion in non-perforated teeth compared to the PTUR+WOG files.

The effect of the KTP laser on smear layer and temperature change: an in vitro study.

The purpose of this study was to evaluate the effects of potassium-titanyl-phosphate (KTP) laser irradiation on smear layer removal and temperature changes of the root surfaces. Two hundred four extracted single-root human premolars were included. The canals were instrumented and divided into two main groups: group A (smear layer examination n:119) and group B (temperature change examination n:85). Each group was divided into subgroups (n:17) according to the different five laser power settings: A1, B1: 1 W-5.33 J/cm2; A2, B2: 1.5 W-7.52 J/cm2; A3, B3: 2 W-10.3 J/cm2; A4, B4: 3 W-15.5 J/cm2, A5, B5: 4 W-20.1 J/cm2, A6: positive control no laser irradiation-irrigated 2 mL for 2 min 2.5% NaOCl + 2 mL distilled water and A7: negative control groups no laser irradiation irrigated 2 mL for 2 min 17% EDTA + 2 mL for 2 min 2.5% NaOCl + 2 mL distilled water. The temperature elevations were measured with an infrared thermographic camera and smear layer examined by scanning electron microscope. According to Kruskal-Wallis and Tukey's tests, in all groups the highest smear scores were in the apical third. In all areas, there were statistically significant differences between negative control group (17% EDTA) and all other groups (p < 0.05). The highest smear scores were determined in 1 W KTP laser and positive control (2.5% NaOCl) groups. Statistically, in all thirds, the differences the 3 W and 4 W KTP laser groups between each other and all other groups were significant (p < 0.05). After the end of the use of the laser, increase in temperature values in all groups were found to be below 10 °C in 20 s.

Evaluation of Various Pretreatments to Fiber Post on the Push-out Bond Strength of Root Canal Dentin.

INTRODUCTION: The aim of this in vitro study was to compare the effect of different pretreatments (fiber post) with the laser-activated irrigation (LAI) technique (for removal of the smear layer) on root canal dentin in terms of push-out bond strength (PBS) in a fiber post. METHODS: Fifty freshly extracted mandibular single-rooted premolars were prepared, and LAI was applied to all roots (17% EDTA was 5 mL for 120 seconds with an erbium, chromium:yttrium-scandium-gallium-garnet laser [0.50 W, 20 Hz, 25 mJ]). In addition, 50 quartz fiber posts were randomly assigned to 5 groups (n = 10) according to the surface treatments as follows: group S (sandblasting), group N1 and group N2 (neodymium:yttrium-aluminum-garnet laser irradiation [2 W, 200 mJ, 10 Hz, with pulse durations of 180 or 320 microseconds), group HF (9.7% hydrofluoric acid etched), and group C (control with no treatment). Dual-cure resin cement was adhered onto the fiber posts after they were covered with a silane agent, and then the posts were placed into the canal space using a Lentulo spiral. The PBS test was performed after all specimens were transversally sectioned (root slices of 1-mm thickness). Data were analyzed with 1-way analysis of variance/Tukey post hoc test (α = 0.05). RESULTS: The highest PBS value was observed in group S (middle part), and the lowest value was observed in group C (apical part). There were no statistical differences among the groups regardless of the part. Furthermore, when the PBS values of the different parts of dentin were compared within treated groups, significant differences were observed in all groups except group N2 (P < .05). CONCLUSIONS: Within the limitations of this study, it can be concluded that the LAI technique when used with 17% EDTA had a significant effect on the amount of smear layer removed from the root canal dentin, which was also detected in the fracture pattern (adhesive failure [resin-post interface]). However, the various treatments of the fiber post did not improve the PBS of the root dentin.

Comparison of Smear Layer Removal Ability of QMix with Different Activation Techniques.

INTRODUCTION: To evaluate the effectiveness of QMix solution (Dentsply Tulsa Dental Specialties, Tulsa, OK) on the smear layer using the following irrigation activation techniques: the EndoActivator (EA) system (Dentsply Tulsa Dental Specialties), photon-initiated photoacoustic streaming (PIPS), and an Er:YAG laser with an endodontic fiber tip. METHODS: Sixty-four extracted single-rooted human teeth were decoronated and the canals instrumented with ProTaper (Denstply Maillefer, Ballagues, Switzerland) up to size F4. The canals were irrigated with 5.25% sodium hypochlorite and a saline solution for 1 minute each. The specimens were then divided randomly into 4 experimental and 4 control groups (n = 8) according to the final irrigation activation technique. These groups included group 1, 2.5 mL QMix; group 2, QMix + EA; group 3, QMix + PIPS; and group 4: QMix + Er:YAG. Laser activated distilled water was used as control groups 5, 6, 7, and 8. Teeth were split longitudinally, and specimens were observed under a scanning electron microscope. Images were taken at the coronal, middle, and apical thirds of the teeth at a magnification of 1000× and were scored in the presence of the smear layer. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests. RESULTS: The highest scores were found in the apical third of all groups (P < .05). The QMix + Er:YAG group removed the smear layer more effectively than the nonactivated QMix group in the apical third (P < .05). The QMix + EA group removed the smear layer significantly in all thirds of the teeth when compared with the nonactivated QMix group (P < .05). The QMix + PIPS group showed a significantly better effect than the QMix group in the coronal third (P < .05). CONCLUSIONS: The EA and Er:YAG laser enhanced the smear layer removal ability of QMix in the apical thirds of the canals. QMix removed more smear layer in the coronal thirds when activated with the PIPS technique.

Efficacy of Laser-Activated Irrigants in Calcium Hydroxide Removal from the Artificial Grooves in Root Canals: An Ex Vivo Study.

OBJECTIVE: The aim of this study was to investigate the efficacy of an erbium chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser with different irrigation solutions [sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA), QMix 2in1, and peracetic acid] in removing calcium hydroxide (CH) from artificial grooves created in root canals. BACKGROUND DATA: CH has to be removed totally before the root canal filling. Any CH residue on the dentin walls may affect the dentinal bond strength and the penetration of sealers into the dentin tubules, and may increase apical leakage. In addition, such a remnant could react chemically with sealers and, possibly, influence physical properties. Therefore, complete removal of CH placed inside the root canals is recommended, using various products and techniques. METHODS: The root canals of 160 extracted single-rooted mandibular premolars were prepared with ProTaper Universal rotary instruments up to size F4. The roots were split longitudinally along the length of the instrumented canals, and a standardized groove was prepared in the apical part of one segment. CH powder mixed with distilled water was placed into the grooves, and the root halves were then reassembled. The roots were randomly divided into two main groups according to the selected irrigation techniques (needle and laser activation) and then each main group was divided into four subgroups according to the final irrigation (NaOCl, EDTA, QMix 2in1, and peracetic acid) protocols used. After irrigation, the roots were disassembled and digital images were taken using a stereomicroscope. Measurements of residual CH were performed as percentages of the overall groove surface area with image analysis software. The data obtained were analyzed using one way analysis of variance and Tukey's honest significant difference tests. Statistical significance was set at p < 0.05. RESULTS: Significantly less residual CH was obtained in the laser-activated groups than in the needle-irrigated groups (p < 0.05). According to both main groups' data, NaOCl left significantly more CH than the other groups (p < 0.05). However, there was no significant difference among the EDTA, QMix 2in1, and peracetic acid groups. CONCLUSIONS: None of the techniques removed the CH dressing completely. Laser-activated irrigation was significantly more effective than needle irrigation.

Efficacy of Laser Activated Irrigation on Apically Extruded Debris with Different Preparation Systems.

OBJECTIVE: The aim of this study was to evaluate apical extrusion of debris in canals prepared with three nickel-titanium (NiTi) rotary file systems [Twisted File Adaptive (TFA), SybronEndo, Orange, CA], Reciproc [(RP), VDW, Munich, Germany], and Revo-S [(RS), MicroMega, Besançon, France] and two irrigation [conventional needle (CNI) and laser-activated (LAI)] techniques. BACKGROUND DATA: Although previous studies have evaluated the amount of apically extruded debris by various instrumentation and irrigation methods, none of them have investigated the effect of LAI during the root canal preparation on debris extrusion. METHODS: Ninety extracted single-rooted human mandibular premolars with straight canals were randomly assigned to six groups (n=15) according to the file and irrigation protocols used: (1) TFA and LAI group, (2) RP and LAI group, (3) RS and LAI group, (4) TFA and CNI group, (5) RP and CNI group, and (6) RS and CNI group. Debris extruded from the apical foramen during root canal preparation was collected into preweighed Eppendorf tubes. The weight of the dry extruded debris was established by subtracting the preinstrumentation and postinstrumentation weight of the Eppendorf tubes for each group. Data were analyzed using the Kruskal Wallis and Mann Whitney U tests with Bonferroni correction to compare groups. RESULTS: LAI groups extruded more debris than CNI groups (p<0.05). However, no statistically significant differences were observed among the file groups when each irrigation method was evaluated separately (p>0.017). CONCLUSIONS: Within the limitations of this study, it can be concluded that the agitation method, such as LAI, had a significant effect on the amount of extrusion.

Efficacy of surface roughness and bond strength of Y-TZP zirconia after various pre-treatments.

OBJECTIVE: The aim of this study was to evaluate surface roughness (SR) and the influence of various surface treatments (STs) on the veneer ceramic shear bond strength (SBS) to Y-TZP zirconia. BACKGROUND DATA: STs can improve the bonding properties of zirconia ceramics. However, little is known about the effect of Er,Cr:YSGG laser irradiation on SBS between zirconia and veneer ceramic/resin cement. METHODS: Eighty ceramic discs of yttria-tetragonal zirconia polycrystals (Y-TZP) were prepared, and specimens were divided into eight groups (n=10): untreated (control), air abrasion, and Er,Cr:YSGG laser irradiation with different energy intensities (1-6 W). Average SR of each specimen was determined with a profilometer, and a veneering ceramic recommended for zirconia was fired into cylinder-shaped Y-TZP specimens. SBS test was performed for each specimen at a crosshead speed of 1 mm/min, and the average means of SBS and SR were calculated. Fracture modes and the surface topography were evaluated with various microscopes after STs. Data were analyzed by using one way analysis of variance (ANOVA) and Tukey honest significant difference (HSD) tests. RESULTS: The highest mean force value was observed in the air abrasion group, and followed by 6 and 5 W laser irradiations, respectively. The difference between control and air abrasion groups was found to be statistically significant (p<0.05). All laser irradiations increased the SBS value, but 1 and 2 W laser irradiations showed no statistically significant differences compared with the control group. However, the SR value for air abrasion group was significantly higher than that of the control group and 1 W (p<0.05), and there were no significant differences between the SR of all the laser groups and the control group. CONCLUSIONS: The result of this study showed that STs with air abrasion and high laser energy intensities (3-6W), can improve the bonding properties of Y-TZP zirconia.

Effects of three different irrigating solutions and KTP laser irradiation on apical leakage: an electrochemical study.

OBJECTIVE: The purpose of this study was to evaluate the effect of three different irrigating solutions (17% EDTA, 10% citric acid and 2.5% NaOCl) and KTP laser irradiation on apical leakage using an electrochemical method. MATERIALS AND METHODS: Sixty extracted single-rooted human teeth with mature apices were instrumented up to a size 35 K-file. After using each file and before proceeding to the next, canals were irrigated with 2 ml of 2.5% NaOCl. All teeth were then randomly divided into four groups. In group 1, the root canals were irrigated with a final flush of 17% EDTA. In group 2, the root canals were irrigated with a final flush of 10% citric acid. In group 3, the root canals were irradiated with KTP laser at 1 W, 4.45 J/cm(2). In group 4, the root canals were irrigated with a final flush of 2.5% NaOCl. The root canals were then filled using the cold lateral condensation method. Apical leakage was evaluated using an electrochemical method over a period of 10 days. Data were analysed using Tukey HSD and Friedmann tests with p = 0.05 as the level for statistical significance. RESULTS: The 17% EDTA and 10% citric acid groups had statistically less apical leakage than the 2.5% NaOCl group at days 7, 8, 9 and 10 (p < 0.05); however, no significant differences were found between the tested groups at the other time intervals (p > 0.05). No significant difference was found between the KTP laser group and other groups tested at all time intervals (p > 0.05). CONCLUSION: All groups were unable to eliminate apical leakage. However, final irrigation with 17% EDTA and 10% citric acid following root canal preparation reduced postobturation apical leakage compared with 2.5% NaOCl irrigation. When KTP laser and the other three irrigants were compared, no significant difference was found.

Effect of chlorhexidine gluconate, Clearfil Protect Bond, and KTP laser on microleakage under metal orthodontic brackets with thermocycling.

OBJECTIVE: The purpose of this study was to evaluate the effects of antimicrobial pretreatments [chlorhexidine gluconate (CHX), Clearfil Protect Bond (CPB), and potassium-titanyl-phosphate (KTP) laser] on microleakage under metal orthodontic brackets. MATERIALS AND METHODS: Sixty freshly-extracted human premolars were randomly assigned to four equal groups: group 1, 37% phosphoric acid; group 2, 37% phosphoric acid + 2% CHX; group 3, 37% phosphoric acid + KTP laser; and group 4, CPB. The teeth were kept in distilled water for 24 h, and thereafter subjected to 500 thermal cycles. Then specimens were sealed with nail varnish, stained with 0.5% basic fuchsin for 24 h, sectioned, and evaluated under a stereomicroscope. Microleakage was scored with regard to the adhesive-tooth interface and the bracket-adhesive interface at both incisal and gingival margins by the same person. Statistical analysis was accomplished by one-way ANOVA and the Kruskal-Wallis test, with significance set at p = 0.05. RESULTS: Microleakage was observed in all groups. No statistically significant difference was observed among all groups in terms of microleakage when bracket-adhesive and bracket-enamel interface along both gingival and incisal margins was evaluated (p > 0.05). CONCLUSIONS: The lowest microleakage scores were observed in the control group. CPB, KTP, and CHX groups did not show significant differences with the control group (p > 0.05), but the mean scores of the CHX group were higher than those of the other two experimental groups.

Bactericidal effect of KTP laser irradiation against Enterococcus faecalis compared with gaseous ozone: an ex vivo study.

OBJECTIVE: The objective of this study was to evaluate the antimicrobial activity of potassium-titanyl-phosphate (KTP) laser and gaseous ozone in experimentally infected root canals. STUDY DESIGN: Eighty single-rooted teeth with straight canals were selected. After preparation and sterilization, the specimens were inoculated with 10 microL Enterococcus faecalis for 24 hours at 37 degrees C. The contaminated roots were divided into 2 experimental groups, 1 negative control group, and 1 positive control group of 20 teeth each: Group 1, KTP laser group; Group 2, gaseous ozone group; Group 3, sodium hypochlorite group (NaOCl) (negative control); and Group 4, saline group (positive control). Sterile paper points used to sample bacteria from the root canals were transferred to tubes containing 5 mL of brain heart infusion broth. Then 10-microL suspension was inoculated onto blood agar plates. The colonies of bacteria were counted and data were analyzed statistically using Kruskal-Wallis 1-way analysis of variance and Mann-Whitney U tests. RESULTS: There were statistically significant differences between all groups (P < .05). The saline group had the highest number of remaining microorganisms. Complete sterilization was achieved in the 2.5% NaOCl group. The KTP laser and gaseous ozone did not completely sterilize the root canals. CONCLUSION: Both KTP laser and gaseous ozone have a significant antibacterial effect on infected root canals, with the gaseous ozone being more effective than the KTP laser. However, 2.5% NaOCl was superior in its antimicrobial abilities compared with KTP laser and gaseous ozone.

Apical extrusion of intracanal debris and irrigant following use of various instrumentation techniques.

OBJECTIVE: The purpose of this study was to compare in vitro the amount of debris and irrigant extruded apically from extracted teeth, using manual technique and crowndown pressureless technique by K3, RaCe, and FlexMaster instruments. STUDY DESIGN: Sixty human single-rooted mandibular premolar teeth were randomly assigned to 4 groups, 15 teeth each. The teeth in 4 groups were instrumented until the working length with RaCe, K3, FlexMaster, and K-type stainless steel instruments respectively. Debris and irrigant extruded from the apical foramen were collected into vials and the amounts were determined. The data obtained were analyzed using Kruskal-Wallis 1-way analysis of variance and Mann-Whitney U tests, with alpha = 0.05 as the level for statistical significance. RESULTS: No statistically significant difference was observed among the groups in terms of debris extrusion (P > .05). On the other hand, a statistically significant difference was observed between K3 and manual technique groups in terms of irrigant extrusion (P < .05). The difference between other groups was not statistically significant (P > .05). CONCLUSION: Based on the results, all instrumentation techniques produced extruded debris and irrigant; however, the engine-driven nickel-titanium systems were associated with less apical extrusion and irrigant.

Root canal treatment of maxillary second premolar with three roots and three canals: clinical cases

An accurate diagnosis of the anatomy of the root canal system is a pre requisite for successful root canal treatment. According to the endodontic literature, maxillary second premolars usually have one root and one canal. The possibility of three roots and three canals in maxillary second premolars is quite small. Diagnostic means such as preoperative radiographs and examination of the pulp chamber floor aid the location of root canal orifices. The aim of this clinical article is to describe the unusual anatomy that was detected in two maxillary second premolars during routine endodontic treatment.