Efficacy of sonic and ultrasonic irrigation devices in the removal of debris from canal irregularities in artificial root canals

Objective: To evaluate the efficacy of different sonic and ultrasonic devices in the elimination of debris from canal irregularities in artificial root canals. Materials and Methods: A resin model of a transparent radicular canal filled with dentin debris was used. Five groups were tested, namely: Group 1 – ultrasonic insert 15.02; Group 2 – ultrasonic insert 25/25 IRRI K; Group 3 – ultrasonic insert 25/25 IRRI S; Group 4 – sonic insert 20/28 Eddy on a vibrating sonic air-scaler handpiece; Group 5 – 20.02 K-file inserted on a Safety M4 handpiece. Two different irrigants (5% sodium hypochlorite and 17% EDTA) and 3 different times of activation (20, 40, and 60 seconds) were tested. Means and standard deviations were calculated and statistically analyzed with the Kruskal-Wallis and Wilcoxon tests (p<0.05). Results: No statistically significant differences were found between the two irrigants used. Group 4 removed more debris than the other groups (p<0.05). Groups 1, 2, and 3 removed more debris than group 5 (p<0.05). A statistically significant difference (p<0.05) was found for the time of activation in all groups and at all canal levels, except between 40 and 60 seconds in group 4 at coronal and middle third level (p>0.05). Conclusions: No significant differences were found between 5% sodium hypochlorite and 17% EDTA. When the time of activation rises, the dentin debris removal increases in all groups. Both sonic and ultrasonic activation demonstrate high capacity for dentin debris removal

Efficacy of sonic and ultrasonic irrigation devices in the removal of debris from root canal irregularities in artificial root canals

Objective: to evaluate the efficacy of different sonic and ultrasonic devices in the elimination of debris from canal irregularities in artificial root canals. Materials and Methods: a resin model of a transparent radicular canal filled with dentin debris was used. Five groups were tested, namely: Group 1 - ultrasonic insert 15.02; Group 2 - ultrasonic insert 25/25 IRRI K; Group 3 - ultrasonic insert 25/25 IRRI S; Group 4 - sonic insert 20/28 Eddy on a vibrating sonic air-scaler handpiece; Group 5 - 20.02 K-file inserted on a Safety M4 handpiece. Two different irrigants (5% sodium hypochlorite and 17% EDTA) and 3 different times of activation (20, 40, and 60 seconds) were tested. Means and standard deviations were calculated and statistically analyzed with the Kruskal-Wallis and Wilcoxon tests (p0.05). Conclusions: no significant differences were found between 5% sodium hypochlorite and 17% EDTA. When the time of activation rises, the dentin debris removal increases in all groups. Both sonic and ultrasonic activation demonstrate high capacity for dentin debris removal

Cyclic fatigue of NiTi instruments used in complex curvatures with continuous or reciprocating rotation

Aim: The aim of present study was to compare cyclic fatigue resistance of Twisted files (TF, Sybron Endo, Glendora, CA) instrument used with continuous rotation and the new Motion (TFAdaptive rotating reciprocation), to evaluate if the new reciprocating motion could affect the lifespan of tested instruments. Methodology: 30 new TF instruments were submitted to cyclic fatigue tests. Group 1 instruments were tested using a TFA motion (TFA) while group 2 instruments were used in continuous rotation at 500 rpm (CR). The cyclic fatigue testing device used in the present study has been used for studies on cyclic fatigue resistance previously. The artificial canal was manufactured to provide the instrument with a very challenging trajectory 60° curvature, with a 2 mm radius. All instruments were rotated or reciprocated until fracture occurred. The time to fracture was recorded. All data were subjected to statistical evaluation with analysis of variance test. Results: TFA reciprocating motion showed a significant increase (p < 0.05) in the time to failure when compared to continuous rotation. Mean time to failure was 131 s (SD ±25.2) for group 1 (TFA), and was 68 s (SD ±14.8) for continuous rotation group (CR). Conclusions: In accordance with those findings, the results of the present study showed a significant increase of cyclic fatigue resistance of instruments used with the TFA motion. This can be explained by the alternance of engaging/disengaging movements, since the motion can be defined as a non-continuous rotation, while the traditional continuous rotation movement continuously engages and stresses the instruments

Morphostructural analysis, saos-2 cell viability and ph evaluation of two calcium silicate-based cement

Aim: The aim of this study was to evaluate the bioactivity of Pro Root MTA (Dentsply, USA) and Biodentine (Septodont, France) after contact with human osteoblast-like cells(Saos-2). Cell viability was assessed by the mitochondrial dehydrogenase enzymatic (MTT) assay. A Ph analysis during the two different cement setting time was performed to evaluate the clinical effect on the pulp of the tested materials. Methods: Human osteogenic sarcoma cells, SaOS-2, were cultured in Dulbecco’s Modified Eagle’s Medium (DMEM;Euroclone,Pero, MI, Italy), supplemented with 10% fetal bovine serum (FBS) and antibiotics, and were maintained in a humidified incubator with 5% CO2 at 37 °C. Cell viability was determined by using MTT assay. Briefly, 5x104 SaOS-2 cells were seeded on Biodentine or MTA Proroot disks and cultured for 24 , 48 and 72 hours. Tetrazolium salts (MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide, 5 mg/mL suspended in PBS), was added to each well and incubated for 4 h. The formazan crystals are extracted from the cells with a solubilizing solution (DMSO). An ELISA reader (Thermo Fisher, Phadia AB, Uppsala, Sweden) was used to measure the optical density at a wavelength of 570 nm and reference length 630 nm. The results were expressed as optical density values. pH measurement The pH was assessed with pH indicator strips at 24, 48 and 72 hours. Results: The cells exposed with the two bioceramic materials showed differences in terms of viability at 24h, 48h and 72h but not statistically different. No differences between the PH after the cement setting at 24h, 48h and 72h was detected: P&gt;0.1. Conclusion: Bioceramic cements revolutioned endodontic procedures. The biggest limit of ProRoot MTA is the low manipulability so, a new cement was introduced in the market (Biodentine) in order to obtain an easier manipulation. Despite the tests reveal comparable results, the possibility to use a material in a humid clinical condition is a big advantage for the clinician especially in pediatric dentistry. Cell Viability and PH value was comparable between the two tested materials. Further study are necessary to well evaluate the exact role of calcium since, according with the existent literature, MTA shows better clinical outcomes especially in pulp capping procedures

Influence of environmental temperature, heat-treatment and design on the cyclic fatigue resistance of three generations of a single-file nickel-titanium rotary instrument

The aim of the present study was to evaluate the effect of environmental temperature, heat-treatment*** and design on the cyclic fatigue resistance of OneShape (OS), OneShape new generation (OSNG) and One Curve (OC) NiTi rotary single-file instruments. Cyclic fatigue testing of NiTi instruments was performed in an artificial canal with a 5-mm radius of curvature and a 60° angle of curvature located 5 mm from the tip of the instrument. During the experiment 3 different temperatures were used in a thermostatic bath with electronic and infrared controls: 0°, 20° and 35 °C. Sixty OneShape, 60 OneShape new generation and 60 One Curve instruments were rotated in the artificial canal until fracture occurred and the number of cycles to fracture (NCF) and the length of the fractured fragment (FL) was recorded. Data were analyzed by one-way ANOVA test at the 5% significance level. Fatigue resistance was significantly higher as the environmental temperature decreased, with differences ranging from 61 to 791%. OC instruments were significantly more resistant to cyclic fatigue than OS and OSNG instruments at all the temperatures tested (P  0.05). Within the limitation of the present study, fatigue resistance of the files was significantly increased when the environmental temperature decreased. OC instruments were significantly more resistant to cyclic fatigue than OS and OSNG instruments at all the temperatures tested

Regenerative Endodontic Procedures Using Contemporary Endodontic Materials

Calcium hydroxide apexification and Mineral Trioxide Aggregate (MTA) apexification are classical treatments for necrotic immature permanent teeth. The first tend to fail for lack of compliance given the high number of sessions needed; the second has technical difficulties such as material manipulation and overfilling. With both techniques, the root development is interrupted leaving the tooth with a fragile root structure, a poor crown-to-root ratio, periodontal breakdown, and high risk of fracture, compromising long-term prognosis of the tooth. New scientific literature has described a procedure that allows complete root development of these specific teeth. This regenerative endodontic procedure (REP) proposes the use of a combination of antimicrobials and irrigants, no canal walls instrumentation, induced apical bleeding to form a blood clot and a tight seal into the root canal to promote healing. MTA is the most used material to perform this seal, but updated guidelines advise the use of other bioactive endodontic cements that incorporate calcium and silicate in their compositions. They share most of their characteristics with MTA but claim to have fewer drawbacks with regards to manipulation and aesthetics. The purpose of the present article is to review pertinent literature and to describe the clinical procedures protocol with its variations, and their clinical application

Cyclic fatigue resistances of Hyflex EDM, WaveOne gold, Reciproc blue and 2shape NiTi rotary files in different artificial canals

The aim of the present study was to compare the cyclic fatigue resistances of HyFlex EDM (HEDM), WaveOne Gold (WOG), Reciproc Blue (RB), and 2Shape (TS) NiTi systems having different metallurgic properties. HEDM, WOG, RB, and TS instruments were rotated in artificial canals which were made of stainless steel with an inner diameter of 1.5 mm, 45°, and 90° angles of curvatures and a radius of curvature of 5 mm until fracture occurred, and the time to fracture (TTF) was recorded in seconds. Also, number of cycles to fracture was calculated (NCF). Data were statistically analyzed using Kruskal-Wallis and t test. The statistical significance level was set at P  0.05). When the NCF values were taken into consideration, HEDM reported a significantly higher cyclic fatigue resistance than TS in both canal curvatures analyzed (P < 0.05). Within the limitations of the present study, RB NiTi files showed statistically higher cyclic fatigue resistance in artificial canals with 45° and 90° than the other NiTi files tested

Cyclic fatigue resistances of Hyflex EDM, WaveOne gold, Reciproc blue and 2shape NiTi rotary files in different artificial canals

The aim of the present study was to compare the cyclic fatigue resistances of HyFlex EDM (HEDM), WaveOne Gold (WOG), Reciproc Blue (RB), and 2Shape (TS) NiTi systems having different metallurgic properties. HEDM, WOG, RB, and TS instruments were rotated in artificial canals which were made of stainless steel with an inner diameter of 1.5 mm, 45°, and 90° angles of curvatures and a radius of curvature of 5 mm until fracture occurred, and the time to fracture (TTF) was recorded in seconds. Also, number of cycles to fracture was calculated (NCF). Data were statistically analyzed using Kruskal-Wallis and t test. The statistical significance level was set at P  0.05). When the NCF values were taken into consideration, HEDM reported a significantly higher cyclic fatigue resistance than TS in both canal curvatures analyzed (P < 0.05). Within the limitations of the present study, RB NiTi files showed statistically higher cyclic fatigue resistance in artificial canals with 45° and 90° than the other NiTi files tested