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This European Society of Endodontology (ESE) position statement on surgical extrusion, intentional replantation and tooth autotransplantation represents the consensus of an expert committee, convened by the ESE. A narrative review in the International Endodontic Journal (Plotino et al. 2020, international Endodontic Journal, 53, 1636–52) formed the basis for the position statement. The review provided detailed information on the background, clinical procedures and the outcome of surgical extrusion, intentional replantation and tooth autotransplantation techniques. The aim of the current statement is to summarize the best available evidence on these clinical techniques to provide appropriate clinical guidance to undergraduate and postgraduate students, dental practitioners, clinical teachers and researchers. The current position statement will be updated by the ESE periodically to reflect new evidence as it becomes available to provide the most current treatment guidance for clinical practice. [ABSTRACT FROM AUTHOR]

Surgical extrusion is defined as the procedure in which the remaining tooth structure is repositioned at a more coronal/supragingival position in the same socket in which the tooth was located originally. Intentional replantation is defined as the deliberate extraction of a tooth and after evaluation of root surfaces, endodontic manipulation and repair, placement of the tooth back into its original position. Tooth autotransplantation is defined as the transplantation of an unerupted or erupted tooth in the same individual, from one site to another extraction site or a new surgically prepared socket. The advent of titanium implant rehabilitation has reduced the use of these treatments in day‐by‐day clinical practice; however, the re‐emerging trend to conserve and preserve natural sound tissues has led to a rediscovery of these treatments. All three distinct surgical methods are closely related, as they act to treat teeth that cannot be predictably treated using other more conventional procedures in endodontics, periodontics and restorative dentistry. Furthermore, these procedures share the same treatment approach and include the atraumatic extraction of a tooth, visual inspection of the tooth/root and its subsequent replantation. The clinical procedures for surgical extrusion, intentional replantation and tooth autotransplantation treatment have undergone several changes in recent years, and currently, there are no clear clinical treatment protocols/guidelines available. The clinician should be aware of the outcome of these treatments. Hence, the aim of this narrative review is to provide the background, clinical procedures and outcomes of surgical extrusion, intentional replantation and tooth autotransplantation. [ABSTRACT FROM AUTHOR]

Aim: To compare two different clinical techniques when using endodontic rotary instruments by monitoring the torque in vivo. Methodology: Ten single‐rooted maxillary anterior teeth were prepared by an endodontist using size 25,.06 taper TF rotary instruments (KerrEndo, Orange, CA, USA). All instruments were rotated at 500 rpm with maximum torque set at 2.5 N cm using an endodontic motor (Kavo, Biberach, Germany), which automatically recorded the torque values every 1/10 of a second. Instruments were used with two modi operandi: (i) Inward action: short‐length intermittent progression with slight apical pressure aiming to reach the working length (also known as pecking motion), followed by (ii) Outward action: lateral brushing action selectively directed to address the canal circumference whilst removing instruments in the coronal direction. The mean, maximum and accumulated torque values were recorded and analysed statistically (t‐test and Wilcoxon test) with a significance level set at 5%. None of the recorded values exceeded the selected torque limit. Results: A significant difference between inward and outward actions was found regarding the evaluated parameters (P < 0.05). The outward action (brushing) was significantly safer (requiring less torque) compared to the inward action (pecking). Conclusions: Torque measurements during in vivo instrumentation provided useful information regarding the techniques evaluated. Although the torque limit was not reached by any of the two actions, the technique impacted significantly on the torque applied to the instrument. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To investigate in vivo the complexity of canals within mesial roots of mandibular molars using 3D Endo™ software linked to CBCT images. Methodology: The CBCT images of 100 mandibular first molars were analysed using the 3D Endo™ software. The number of canals in the mesial roots, the presence of apical confluences, the canal lengths and the canal configurations using Vertucci's classification were evaluated in buccolingual (BL) and mesiodistal (MD) views. The software allowed the visualization of canal trajectories in three dimensions using a coloured outline, which was used to develop a new objective scoring system to provide an overall assessment of canal complexity. Data were analysed statistically using anova and t‐tests with the significance set at P < 0.05. Results: Vertucci type IV canals were found in 44% of the cases, whilst 54% were type II. The mean distance from the apical foramen to the orifice was 13.15 mm (±1.21) and that between a confluence and the foramen, 2.81 mm (±1.13). The number of curvatures and the canal complexity scores in the MD view were significantly higher than in the BL view (P < 0.05). The scores were not directly correlated to the canal (MB versus ML), to the canal length or to the presence of confluences. Conclusions: 3D Endo software features the automatic detection and measurement of several anatomical canal parameters, and is a promising tool for the study of canal complexity in vivo. The unpredictable anatomy of the mesial roots of mandibular molars highlights the value of a three‐dimensional preoperative evaluation of each case. The proposed scoring system aims to provide the clinician with an overall assessment of canal complexity. [ABSTRACT FROM AUTHOR]

The article discusses the 1st European Society of Endodontology (ESE) Clinical Meeting held in ACTA, Amsterdam, the Netherlands, on Saturday the 27th October 2018. Particular focus is given to the meeting's overarching theme: the design and preparation of access cavities during root canal treatment. Additional topics discussed include the basic principles of access cavity design, traditional access cavity designs and clinical challenges and current trends relating to the subject.

Aim To assess resistance to cyclic fatigue of reciprocating nickel-titanium ( NiTi) files ( Reciproc and Wave One) after immersion in NaOCl solution over several time periods. Methodology A total of 90 new Reciproc R25 and WaveOne Primary were tested. The 45 files of the same brand were randomly assigned to three groups ( n = 15) and submitted to the following immersion protocol in 5% NaOCl at 37 °C for 16 mm: no immersion (control), 1 or 5 min dynamically. The dynamic immersion and the following cyclic fatigue tests were performed using the appropriate preset reciprocation modes (' RECIPROC ALL' or ' WAVEONE ALL') in a specially designed endodontic motor. Resistance to cyclic fatigue was determined by recording time to fracture ( Tt F) in a stainless steel artificial canal with a 60° angle of curvature and 5 mm radius of curvature. The artificial canal was manufactured reproducing the instrument's size and taper. Data were analysed by 2-way analyses of variance. Results Resistance to cyclic fatigue of the same NiTi file was not significantly affected by immersion in NaOCl. Reciproc R25 was associated with a higher cyclic fatigue resistance in all groups compared to Wave One Primary ( P < 0.0001). Conclusions Reciprocating dynamic immersion in NaOCl for 1 or 5 min did not reduce the cyclic fatigue resistance of NiTi files significantly. However, the type of reciprocating instrument influenced cyclic fatigue resistance with Reciproc R25 being more resistant than Wave One Primary. [ABSTRACT FROM AUTHOR]

Gambarini G, Gergi R, Naaman A, Osta N, Al Sudani D. Cyclic fatigue analysis of twisted file rotary NiTi instruments used in reciprocating motion. International Endodontic Journal, 45, 802-806, 2012. Abstract Aim To evaluate the cyclic fatigue fracture resistance of engine-driven twisted file (TF) instruments under reciprocating movement. Methodology A sample of 30 size 25, 0.08 taper NiTi TF instruments was tested in a simulated canal with 60˚ angle of curvature and a 3 mm radius. During mechanical testing, different movement kinematics were used at a constant speed, which resulted in three experimental groups (each group n = 10). The instruments from the first group (G1) were rotated until fracture occurred. The instruments in the second (G2) and third group (G3) were driven under reciprocating movement with different angles of reciprocation. The time of fracture for each instrument was measured, and statistical analysis was performed using one-way analysis of variance followed by Tukey's Honestly Significant Different test. Results Reciprocating movement resulted in a significantly longer cyclic fatigue life ( P < 0.0001) when compared with continuous rotation. No difference was found between reciprocation 150° clockwise/30° counterclockwise (CW/CCW) and 30° CW/150° CCW. Conclusions The reciprocating movement was associated with an extended cyclic fatigue life of the TF size 0.25, 0.08 taper instruments in comparison with conventional rotation. [ABSTRACT FROM AUTHOR]

Plotino G, Grande NM, Testarelli L, Gambarini G. Cyclic fatigue of Reciproc and WaveOne reciprocating instruments. International Endodontic Journal, 45, 614-618, 2012. Abstract Aim To evaluate the cyclic fatigue resistance of Reciproc ® and WaveOne ® instruments in simulated root canals. Methodology Two groups of 15 NiTi endodontic instruments of identical tip size of 0.25 mm were tested, group A; Reciproc ® R25 and group B: WaveOne ® primary. Cyclic fatigue testing was performed in a stainless steel artificial canal manufactured by reproducing the instrument's size and taper. A simulated root canal with a 60° angle of curvature and 5-mm radius of curvature was constructed for both the instruments tested. The centre of the curvature was 5 mm from the tip of the instrument and the curved segment of the canal was approximately 5 mm in length. The Reciproc ® instruments were activated using the preset programme specific for the Reciproc ® instruments, whilst the WaveOne ® instruments were activated using the preset programme specific for the WaveOne ® instruments. All instruments were rotated until fracture occurred and the time to fracture (TtF) and the length of the fractured tip were recorded and registered. Means and standard deviations of TtF and fragment length were calculated for each system and data were subjected to Student's t-test ( P < 0.05). Results A statistically significant difference ( P < 0.05) was noted between Reciproc ® and WaveOne ® instruments. Reciproc ® R25 instruments were associated with a significant increase in the mean time to fracture when compared with primary WaveOne ® instruments (130.8 ± 18.4 vs. 97.8 ± 15.9 s). There was no significant difference ( P > 0.05) in the mean length of the fractured fragments between the instruments. Conclusions Reciproc ® instruments were associated with a significantly higher cyclic fatigue resistance than WaveOne ® instruments. [ABSTRACT FROM AUTHOR]

Aim To investigate whether flexibility and cyclic fatigue resistance was increased for nickel-titanium instruments produced by a new manufacturing technique. Methodology Forty K3 tip size 25, 0.06 taper (SybronEndo) nickel-titanium rotary instruments were randomly selected and divided into two groups (n = 20). One group served as control, being the commercially available instruments produced with a traditional grinding process (K3). The second group of instruments (K4 prototypes) were then subjected to a proprietary thermal treatment after the grinding process. Finally, each group was randomly divided into two subgroups of 10 instruments each, to perform the stiffness test and the cyclic fatigue test. All data were recorded and subjected to statistical evaluation using Student's t-test. Significance was set at the 95% confidence level. Results For the stiffness test, a statistically significant difference (P < 0.05) was noted between K3 and K4 prototype instruments. K4 prototype instruments were significantly more flexible when compared to K3 instruments (59.3 ± 4.3 vs. 98.1 ± 6.4 g cm-1). For the cyclic fatigue test, a significant difference (P < 0.05) was noted between K3 and K4 prototype instruments. K4 prototype instruments demonstrated a significant increase in the mean number of cycles to failure (NCF) when compared to K3 instruments (1198 ± 279 vs. 542 ± 81 NCF). Conclusions The new manufacturing technique resulted in the K4 prototype instruments having enhanced mechanical properties, compared to K3 instruments, manufactured with a traditional grinding process. [ABSTRACT FROM AUTHOR]

Aim To discuss the use of cone-beam computed tomography (CBCT) in the differential diagnosis of a case of labiomandibular paraesthesia caused by extrusion of endodontic sealer into the mandibular canal. Summary A 59-year-old woman suffering from a paraesthesia on the left posterior mandible and numbness on the left side of the lower lip was referred to an endodontic specialist 1 month after multiple root canal treatments. A panoramic radiograph revealed the presence of extruded root filling material beyond the apex of the mesial root of the mandibular left second molar and also beyond the apex of the first premolar. A cone beam computed tomography examination was undertaken, which confirmed the presence of radiopaque root canal filling material in the periapical area of the second molar, and revealed that the material was inside the mandibular canal. No extruded filling material was found inside the mental foramen beyond the apex of the first premolar tooth. Key learning points Small field of view CBCT (where possible) can be considered an effective radiographic diagnostic device when endodontic-related inferior alveolar nerve or mental foramen paraesthesia are suspected. CBCT is able to provide detailed three-dimensional images of the tooth, the root canal system and the surrounding tissue. [ABSTRACT FROM AUTHOR]

Plotino G, Grande NM, Melo MC, Bahia MG, Testarelli L, Gambarini G. Cyclic fatigue of NiTi rotary instruments in a simulated apical abrupt curvature. International Endodontic Journal, 43, 226–230, 2010. Aim To evaluate the cyclic fatigue resistance of five NiTi rotary systems in an abrupt apical curvature. Methodology Cyclic fatigue testing was performed in stainless-steel artificial canals with a 2-mm radius of curvature and an angle of curvature of 90° constructed to the dimensions of the instruments tested. The middle of the simulated curvature was 2.5 mm from the tip of the instrument that was placed at full working length. All instruments were new and 25 mm in length. Ten ProTaper Universal F2 (Dentsply Maillefer, Ballaigues, Switzerland); FlexMaster (VDW, Munich, Germany) tip size 25, taper 0.06; M two (Sweden & Martina, Padova, Italy) tip size 25, taper 0.06; ProFile tip size 25, taper 0.06 from Dentsply Maillefer (Ballaigues, Switzerland); and ProFile tip size 25, taper 0.06 from Dentsply Tulsa (Tulsa, OK, USA) were rotated passively at 300 rpm until fracture occurred, and the number of cycles to failure (NCF) recorded. Length of the fractured tip was measured. Data were analysed by one-wayanova and Tukey HSD test to determine any statistical difference amongst groups. Results M two had the highest fatigue resistance compared to the other instruments (NCF 124 ± 25) ( P < 0.001); there was no statistical difference between ProFile from the two different brands, although ProFile from Maillefer had the higher fatigue life (NCF 75 ± 10) compared to ProFile from Tulsa (NCF 66 ± 10). No difference was registered between FlexMaster (NCF 53 ± 5) and ProFile from Tulsa; ProTaper F2 had a significantly ( P < 0.001) lower fatigue life compared to the other instruments tested (NCF 29 ± 5). Conclusions Lifespan registered for the instruments tested in an apical abrupt curvature was M two > ProFile from Maillefer > ProFile from Tulsa > FlexMaster > ProTaper. [ABSTRACT FROM AUTHOR]

Aim To investigate the influence of the trajectory of NiTi rotary instruments on the outcome of cyclic fatigue tests. Methodology Ten ProFile and M two instruments tip size 20, taper 0.06 and tip size 25, taper 0.06 were tested in two simulated root canals with an angle of curvature of 60° and radius of curvature of 5 mm but with different shape. Geometrical analysis of the angle and radius of the curvature that each instrument followed inside the two different artificial canals was performed on digital images. The instruments were then rotated until fracture at a constant speed of 300 rpm to calculate the number of cycles to failure (NCF) and the length of the fractured fragment. Mean values were calculated and analysed using two different multivariate linear regression models and an independent sample t-test. Results The shape of the artificial root canal used in cyclic fatigue studies influenced the trajectory of the instrument. This difference is reflected by the NCF measured for the same instrument in the different artificial root canals and by the impact of the type of canal on both the NCF (St.β = 0.514) and fragment length (St.β = −0.920). Conclusions Small variations in the geometrical parameters of the curvature of an instrument subjected to flexural fatigue could have a significant influence on the results of fatigue tests. [ABSTRACT FROM AUTHOR]

Aim To determine the influence of volume, irrigant and method of flushing on the removal of artificially-placed dentine debris from the apical part of root canals during passive ultrasonic irrigation. Methodology Access cavities were prepared in 15 canine teeth and their root canals instrumented to size 20, 0.10 taper. Each root was split longitudinally, forming two halves. A groove was cut in the canal wall 2–6 mm from the apex in each half which was then filled with dentine debris prior to the roots being reassembled. All canals were ultrasonically irrigated, using a size 15, 0.02 taper smooth wire to a length of 21 mm that was placed in the canal to the apical foramen. In group 1 the canal was flushed with a continuous flow of 50 mL 2% sodium hypochlorite (NaOCl). In group 2 the continuous flow was not used but the canal was flushed with 12 mL 2% NaOCl, at a rate of 2 mL 30 s−1 using a syringe. Group 3 was treated in the same way as group 2 but the canal was flushed with 6 mL 2% NaOCl, at a rate of 2 mL min−1. Group 4 was treated in the same way as group 1 but water was used as the irrigant. Before and after irrigation, images of the grooves were captured and stored. The quantity of dentine debris in the groove was evaluated. The differences in debris scores between the experimental groups were analysed with the Kruskal–Wallis test and the Mann–Whitney U-test. The level of significance was set at P = 0.05. Results The difference between all groups was statistically significant (K–W test P < 0.001).Groups 1, 2 and 3 differed significantly from group 4 ( P < 0.001); there was no significant difference between groups 1, 2 and 3 ( P = 0.550). Conclusions Syringe delivery of 2% NaOCl (6 and 12 mL) was as effective as a continuous flow of 2% NaOCl (50 mL). Water was not effective in removing dentine debris from grooves in the apical portion of root canals. [ABSTRACT FROM AUTHOR]

Aim To evaluate calcium ion release and pH-characteristics of calcium hydroxide plus points (CHPP), conventional calcium hydroxide points (CHP, both Coltène/Whaledent, Langenau, Germany) and aqueous calcium hydroxide suspension (CHS) (Calxyl, OCO, Dirmstein, Germany). Methodology Ten CHPP or CHP of size 50 were immersed into 5 mL isotonic sodium chloride solution. Conventional Ca(OH)2-free gutta-percha points served as negative control. Calcium release was measured up to 44 days by means of complexometric titration. Time dependent pH behaviour of all points in comparison with CHS was determined immersing 30 points of size 50 into 2.3 mL 0.9% wt NaCl-solution at time intervals of 0.5–72 h by a microelectrode measuring chain and a pH-meter. The surface morphologies of new and used gutta-percha points were evaluated qualitatively under a scanning electron microscope. Statistical evaluation was carried out using Kolmogorov–Smirnov-tests, Mann–Whitney-tests and multifactorial anova. Results For CHPP, a threefold greater calcium release was measured compared with CHP. Both types of points as well as CHS showed a maximum pH of approximately 12. Differences between groups were statistically significant for calcium release and pH (multifactorial anova; P < 0.001). Both types of points showed porous surfaces after usage, with a rougher surface for CHPP. Conclusions CHPP and CHP increased the pH of isotonic sodium chloride >11 within 3 min. CHPP had a greater release of Ca2+ compared with CHP. [ABSTRACT FROM AUTHOR]

Abstract Aim The aim of the present study was to assess debris and smear layer remaining following canal preparation with GT rotary instruments. Methodology Sixteen freshly extracted single-rooted premolar teeth were instrumented with GT™ rotary instruments using a crown-down preparation technique. All specimens were flushed with 2 mL of 5% NaOCl between each rotary instrument. At the end of instrumentation the following final irrigation sequence was repeated two times: 2 mL of EDTA + Cetrimide for 1 min (Largal Ultra, Septodont, France) and 2 mL of 5% NaOCl for 5 min. A final flush with saline solution was made to halt any chemical activity. Two other uninstrumented teeth that were not irrigated served as controls. All teeth were split longitudinally and prepared for SEM evaluation. The presence of debris and smear layer was evaluated from photomicrographs at ×200 and ×1000 magnification taken in the apical, middle and coronal thirds of the canals. Blind evaluation was performed by two trained observers and scores were compiled separately. A five category scoring system for debris and smear layer was used. Values obtained were tabulated and statistical analysis was carried out using a parametric chi-squared test. Results Statistical analysis showed that there was no significant difference between the three regions of the root canals (P > 0.05) for debris. Comparison of the removal of the smear layer between the three regions showed that there was a statistically significant difference between all parts, especially between the coronal and apical thirds (P < 0.001). Overall, the coronal sections were cleaner than the middle and apical sections. The uninstrumented canals showed walls completely covered with tissue, confirming that specimen preparation alone did not remove tissue. Conclusions Under the conditions of the present study GT™ rotary instruments removed debris effectively, but left root canal walls covered with smear layer,... [ABSTRACT FROM AUTHOR]

Abstract Aim The purpose of the present study was to evaluate resistance to cyclic fatigue of new and used ProFile Ni–Ti rotary instruments. Methodology Used instruments were operated in 10 clinical cases using passive instrumentation and a crown-down preparation technique. Cyclic fatigue testing of new and used engine-driven instruments was then performed with a specific device which allowed the instruments to rotate freely inside a stainless steel artificial canal, whilst maintaining conditions close to the clinical situation. Instruments were rotated until fracture occurred and time to fracture was visually recorded with a chronometer. Results A significant reduction of rotation time to breakage (life span) was noted between new and used instruments. In all sizes new instruments were significantly more resistant than used ones (two-sample t-test, P < 0.01). No instrument underwent intracanal failure during clinical use. Conclusions Prolonged clinical use of Ni–Ti engine-driven instruments significantly reduced their cyclic fatigue resistance. Nevertheless, each rotary instrument was successfully operated in up to 10 clinical cases without any intracanal failure. [ABSTRACT FROM AUTHOR]

Abstract – Fracture of nickel-titanium rotary files is an iatrogenic error which can seriously jeopardize root canal therapy. If a high-torque motor is used, the instrument-specific limit-torque (fracture limit) is often exceeded, thus increasing the risk of intracanal failure. A possible solution to this problem is to use a low-torque endodontic motor which operates below these values. If the torque is set just below the limit of elasticity for each instrument, the risk of fracture is likely to be markedly reduced. The purpose of this paper was to discuss mechanical properties of NiTi rotary instruments, the rationale for selecting low torque values, and to use clinically a new endodontic motor (step-motor) which operates below the limit of elasticity of each rotary file. The step-motor was found to be helpful in reducing the risk of instrument fracture. Irreversible material damage (plastic deformation) and instrument fracture were rarely seen. Low-torque instrumentation also increased tactile sense and, consequently, mental awareness of rotary instrumentation. [ABSTRACT FROM AUTHOR]

The polymerization of methacrylic monomers present in dental composite resins never reaches completion and therefore the leakage of residual monomers into the oral cavity and into biological fluids can cause local and systemic adverse effects. This work was carried out to study the in vitro biochemical interactions of urethane dimethacrylate and 1,4-butanediol dimethacrylate monomers with HL-60 cells, a cell line assumed as an experimental model for simulating granulocyte behaviour. Our main finding was that both monomers induce cell differentiation at toxic concentrations and that cytotoxicity seems to be caused by alterations of glucose metabolism arising from mitochondrial dysfunction rather than from oxidative stress, which could not be altogether verified under our experimental conditions. Our study could be considered as a useful approach to investigate the biochemical mechanisms that contribute to the cytotoxicity of methacrylate compounds and it underlines the importance of assessing such parameters for testing biocompatibility in order to promote the development of better and safer dental materials.