Debris and Smear Layer Removal in Curved Root Canals: A Comparative Study of Ultrasonic and Sonic Irrigant Activation Techniques.

The aim of this study was to compare the cleaning efficacy of three irrigant activation devices with a control of non-activated syringe and needle irrigation in curved root canals. Sixty human curved roots were endodontically prepared and divided into four groups (n = 15) with similar root curvature distributions. Final irrigation using 4% NaOCl was performed with a syringe and needle (30-G) alone, or with Eddy sonic powered irrigation system (polymeric tip #0.25/0.06), Endosonic ultrasonic activation (polymeric tip #0.25/0.03), or Irrisafe ultrasonic activation (stainless-steel tip, #0.25/0.00). SEM was used to evaluate cleaning efficacy, employing five-score systems for debris and smear layer. While no significant difference in debris removal was observed between Endosonic or Irrisafe activation and non-activated irrigation, Eddy sonic powered irrigation system significantly improved debris removal in the apical third of curved root canals. Smear layer removal was effective in coronal and mid-root sections for all groups but less so in the apical third. Thus, Eddy sonic powered irrigation system demonstrated higher efficacy in removing debris from the apical third of curved root canals compared with non-activated syringe and needle irrigation. However, all three irrigant activation systems exhibited no difference from the non-activated control in smear layer removal.

Preparation and filling of small oval root canals: influence of file system and sealer.

OBJECTIVE: To carry out a morphometric analysis of small oval root canals prepared with different instruments (part 1) and filled with different sealers (part 2). METHOD AND MATERIALS: Ninety extracted mandibular incisors with small oval root canals were instrumented with Self-Adjusting File (n = 45), XP-endo Finisher (n = 15), GentleFile (n = 15), or Reciproc (n = 15). All groups of part 1 were filled with AH Plus (n = 15 each). For part 2 (including group Self-Adjusting File/AH Plus) teeth instrumented with Self-Adjusting File were additionally filled with GuttaFlow Bioseal (n = 15) or Total Fill BC sealer (n = 15). All sealers were placed with a lentulo and filled with master point and additional points. Serial cuts were made at 1-mm intervals up to 10 mm. Total root canal area, percentage of gutta-percha filled area (PGFA), sealer, voids, and debris were evaluated using interactive image analysis software. RESULTS: Preparation with Reciproc caused significantly wider canals than with Self-Adjusting File, GentleFile, or XP-endo Finisher, but also resulted in the greatest PGFA and lowest percentage of sealer (P ≤ .05). Following XP-endo Finisher, the significantly greatest percentage of debris (30%) was found 1 mm from the apex (P ≤ .05). Regarding different sealers, only minor differences were found (GuttaFlow Bioseal: less percentage of sealer at 2 and 3 mm levels [P ≤ .05]). CONCLUSION: Within the limits of this study Reciproc caused the greatest substance loss, but also the most favorable PGFA. The apical debris accumulation with XP-endo Finisher needs further investigation. The sealers under investigation performed equally well.

Can Type of Instrumentation and Activation of the Final Irrigant Improve the Obturation Quality in Oval Root Canals? A Push-Out Bond Strength Study.

To appraise the outcome of file systems and activation of the final irrigant on the push-out bond strength of root fillings in oval canals. Single-rooted mandibular premolars (n = 180) with oval canals were divided into three groups (n = 60) for instrumentation: ProTaper Next (PTN), WaveOne (WO), and Self-adjusting File (SAF). The specimens were further divided into subgroups (n = 20) and subjected to final irrigation with activation by EndoActivator or passive ultrasonic irrigation or without activation. Then, the specimens were again subdivided (n = 10) and obturated with gutta-percha and AH Plus (GP-AH) or C-Point with EndoSequence bioceramic sealer (C-EBC). One-millimeter-thick horizontal slices were cut from the apical third of the root, 5 mm from the apex, and subjected to push-out bond strength (BS) testing. Specimens for which SAF was used exhibited higher BS values than those for which PTN or WO was used (p < 0.05). Activation of the final irrigation did not affect the BS of the root fillings. Root fillings made of C-EBC presented a higher BS than those made of GP-AH (p < 0.05). Adhesive failure was more common with specimens instrumented using PTN and WO. Root canals instrumented with SAF, showed the highest bond strength values for both root filling materials. The C-EBC produced significantly higher bond strength values than those of the GP-AH.

Reflected near-infrared light versus bite-wing radiography for the detection of proximal caries: A multicenter prospective clinical study conducted in private practices.

OBJECTIVES: The aim of the present prospective multicenter clinical study was to compare the detection of proximal caries with near-infrared light reflection (NILR) versus bitewing radiography (BWR). MATERIALS AND METHODS: Intraoral scans were performed on 100 patients in five dental clinics using an intraoral scanner (iTero Element 5D, Align Technology, Tempe, AZ, USA) that includes a near-infrared light source (850 nm) and sensor. Reflected near-infrared light images of posterior teeth were used by the individual dentists to detect proximal caries and the results were compared to the BWRs. In a total of 3499 proximal surfaces of molars and premolars which were examined, 223 carious lesions were detected by BWR, while NILR detected 549 carious lesions. Caries detection using both methods was also done by an expert team of five dentists, highly experienced in NILR image interpretation, who used the same sets of clinically-obtained data. Sensitivity, specificity, and accuracy were calculated for caries detection by both the dentists and the expert team. Fifty-nine of the detected carious lesions were clinically treated and the observations during caries excavation were compared with those done with NILR and BWR. Statistical analysis to compare between NILR and BWR diagnosis was performed using non-parametric two-sided McNemar's Chi-Square test with the significance level set at p < 0.05. Kappa coefficients were calculated to assess the level of agreement between the two caries detection methods. RESULTS: Accuracy of NILR detection of early enamel lesions was 88% and that of carious lesions involving the dentino-enamel junction (DEJ) was 97%. Accuracy was found to be higher at 96% and 99%, respectively, when the same data were examined by the expert team. Direct observation during caries-excavation treatment suggested that NILR detected early enamel lesions that were not detectable with BWR alone. CONCLUSIONS: Within the limitations of the present study, NILR was more sensitive than BWR in detecting early enamel lesions and comparable to BWR in detecting lesions that involved the DEJ. CLINICAL RELEVANCE: Reflected near-infrared light images that are generated simultaneously with 3D intra-oral scanning may be used reliably for detection, screening, and monitoring of proximal caries, thus potentially minimizing the traditional use of ionizing radiation.

Enterococcus faecalis sustained infection induces macrophage pro-resolution polarization.

AIM: To investigate macrophage function in the presence of sustained infection with Enterococcus faecalis, a prevalent root canal resident in asymptomatic apical periodontitis. METHODOLOGY: The human monocyte cell line (THP-1) was differentiated into macrophages by exposure to phorbol myristate acetate (PMA), and the cultures were inoculated with E. faecalis for up to 48 h. At three time-points 90 min, 24 and 48 h after inoculation, the macrophages and their supernatants were examined. Assays included macrophage phagocytosis rate and vitality, bacterial survival, reactive oxygen species (ROS) production, mitochondrial activity, cytokine production and the expression of pro/anti-inflammatory M1/M2 markers. Also, periapical tissue from apicectomy samples of human endodontically treated teeth were collected for histological and immunofluorescent analysis. Statistical differences were analysed with RM ANOVA. RESULTS: E. faecalis were phagocytized, and subsequently, most of the macrophages underwent apoptosis and necrosis. The small population of macrophages that remained vital after 48 h post-inoculation harboured surviving bacteria. Despite a reduction in the number of macrophages over time, the mitochondrial activity of the surviving macrophages remained constant and external ROS decreased, whereas internal ROS increased. During the infection, a shift to a M2 macrophage population at 48 h post-infection was observed; the results were similar to those obtained in periapical human tissue biopsies (p < .05). CONCLUSIONS: The study portrays a continuous non-resolved infection with E. faecalis and activation of macrophages that are polarized to the M2 pro-resolution phenotype.

Apical debris extrusion during instrumentation of oval root canals in primary teeth using manual versus motorized files: an ex vivo study.

This study aimed to assess the apical extrusion of debris during instrumentation of primary canines using three endodontic file types. Forty-five extracted primary canines were randomly assigned to three instrumentation groups (n = 15): Hand K-files; and the motorized Kedo-S files and XP-endo Shaper files. The apically extruded debris produced during the procedure was collected and dried in pre-weighed Eppendorf tubes, and the mass of debris was calculated. The time required for the endodontic procedure was also recorded. Analysis of variance (ANOVA) and Tukey's post hoc test were used with a significance level set at 5%. XP-endo Shaper and Kedo-S files extruded significantly less debris compared with hand K-files with means of 0.84 ± 0.31 and 1.20 ± 0.67 mg respectively, compared to 2.13 ± 0.31 mg (p < 0.0001). No significant difference was found between the two motorized files. Less time was required to complete the procedure with the XP-endo Shaper compared to the hand K-files (p < 0.0001) and Kedo-S files (p < 0.0001). Within the limitations of the present study, it may be concluded that motorized files extruded less debris and required less instrumentation time compared to traditional K-files, which could benefit paediatric patients with root canal treatment needs.

Effect of Adaptive, Rotary, and Manual Root Canal Instrumentation in Primary Molars: A Triple-Armed, Randomized Controlled Clinical Trial.

This clinical trial focused on collating the instrumentation time and quality of root canal obturation in primary molars treated with three instrumentation techniques: adaptive, rotary, and manual. A triple-armed, randomized controlled clinical trial was performed on 75 primary molars requiring pulpectomy treatment, divided into three groups (n = 25 per group). The teeth in Group 1 were instrumented with an adaptive technique (XP-endo Shaper, FKG Dentaire, La Chaux-de-Fonds, Switzerland), Group 2 with pediatric rotary files (Kedo-S; D1 and E1), and Group 3 with a manual technique (hand K-files). The apical size of the final instrumentation was maintained at #30 for all groups. Instrumentation time and the grade of the root canal obturation were evaluated. Instrumentation duration was recorded, employing a digital stopwatch from the insertion of the first file until the completion of final irrigation. Obturation quality was assessed using radiographs. The criteria taken as a reference for obturation were: optimal (1 mm short of the apex), underfilled (2 mm short of the apex), or overfilled (beyond the apex). The use of an adaptive technique was associated with the lowest instrumentation time (p < 0.0001) when used for instrumenting primary molars and with the highest root canal filling quality of the three groups. The application of the new concept of adaptive instrumentation for pulpectomy of primary molars was a favorable technique, considering the significant reduction in instrumentation time and better obturation.

Filling of small oval root canals: influence of sealer placement and filling technique.

Objectives: The aim of this study was to carry out a morphometric analysis of small oval root canals filled with GuttaFlow 2 sealer (Coltène/Whaledent) using different methods of sealer placement and different root canal filling techniques.
Method and materials: Eighty extracted mandibular incisors with small oval root canals were instrumented with the Self-Adjusting File (Redent Nova). GuttaFlow 2 was placed using a lentulo spiral, paper point, master point, or sonically activated CanalBrush (Coltène/Whaledent), followed by the placement of a master point and accessory points (M?P+) (part 1). GuttaFlow 2 was placed using a lentulo spiral without a gutta-percha point, together with a single point, with a chloroform-dipped master point, or the latter with accessory points (ChMP+) (part 2). Serial cuts were made at 1-mm intervals up to 10 mm. The percentages of gutta-percha filled area (PGFA), sealer, voids, and debris were evaluated using interactive image analysis software.
Results: For part 1 of the study (sealer placement), significant differences regarding PGFA at 2 and 5 mm from the apex were found, whereas for part 2 (filling technique), significant differences were found at all levels besides 2 and 4 mm (Kruskal-Wallis test, P = .05). ChMP+ reached 85% PGFA at 3 mm from the apex, but only 30% near the apex. The MP+ groups showed a relatively equal distribution of PGFA by 60% to 80% at different levels. GuttaFlow 2 without a gutta-percha point exhibited significantly more voids and debris than the other groups (Kruskal-Wallis test, P = .05).
Conclusion: Within the limits of this study, MP+ could be recommended for clinical use. The presence of voids and debris for the group without a gutta-percha point needs further investigation.

Prevalence of dens invaginatus in young Israeli population and its association with clinical morphological features of maxillary incisors.

Dens invaginatus is an anomaly mostly observed in maxillary incisors. This study aimed to assess the prevalence of dens invaginatus in maxillary incisors in young Israeli population and to study its potential association with clinical coronal morphological features. Data was collected from periapical radiographs and clinical photographs of patients from Orthodontics Department between 2006 and 2018. Radiographic characteristics were evaluated and compared to clinical coronal morphological features. Statistical analysis was performed using the Pearson chi-square test with statistical significance set at p < 0.05. The sample included 1621 maxillary incisors from 547 patients. Dens invaginatus was observed in 422 (26%) of these teeth. Maxillary lateral incisors were more affected than central incisors. In 103 patients dens invaginatus was unilateral, while in all other cases it was bilateral. Unique clinical morphological characteristics were observed in 88% of the teeth that exhibited radiographic evidence of dens invaginatus. Dens invaginatus Type I was most frequently observed, accounting for 90% of the teeth. A significant association between clinical coronal morphological features and dens invaginatus was detected. Dens invaginatus is common in maxillary incisors of the study population. Several clinical morphological features may predict the presence of dens invaginatus.

Cleanliness and erosion of root canal walls after irrigation with a new HEDP-based solution vs. traditional sodium hypochlorite followed by EDTA. A scanning electron microscope study.

OBJECTIVES: To compare the cleanliness and erosion of root canal walls after the use of a new HEDP (1-hydroxyethane-1,1-diphosphonic acid) -based irrigant with that achieved by irrigation with sodium hypochlorite followed by EDTA. MATERIALS AND METHODS: Forty recently extracted single-rooted teeth were prepared with ProTaper Next files to size X3, using either HEDP-containing 3% sodium hypochlorite, throughout the procedure (n = 20), or 3% sodium hypochlorite followed by a final rinse with 17% EDTA (n = 20), which were both applied with a syringe and needle. Ten additional teeth were prepared and irrigated with saline and served as negative controls. The teeth were split longitudinally and subjected to SEM evaluation for the presence of a smear layer, debris, and erosion of the root canal wall. The Pearson chi-square test was used to compare the results, and the level of significance was set at p < 0.05. RESULTS: In both groups, there were more cases with a smear layer in the apical third of the root canal than in the coronal third, but the groups did not differ from each other significantly (p = 0.545). The root canal walls in both groups were almost free of debris, showing no difference between the groups (p = 0.342). Moderate erosion of the root dentine was found in 10-26% of the cases in both groups, but severe erosion was detected in only one case in each of the groups, which did not differ significantly from each other (p = 0.606). CONCLUSION: Within the limitations of the present study, the HEDP-based irrigation solution did not differ from 3% sodium hypochlorite followed by EDTA in terms of cleanliness or the incidence of erosion of the canal wall. CLINICAL RELEVANCE: When used with syringe and needle irrigation, the new HEDP-based irrigant is convenient and safe but should not be expected to result in cleaner canal walls than 3% sodium hypochlorite followed by 17% EDTA.

Root canal configuration and root wall thickness of first maxillary premolars in an Israeli population. A Cone-beam computed tomography study.

Anatomical features of first maxillary premolars may greatly affect endodontic and following restorative treatments. The aim of this study was to evaluate root canal configuration and root wall thickness of first maxillary premolars using a preexisting CBCT database. A CBCT database of 400 first maxillary premolar was used to study canal configuration, presence of furcation-facing groove on the buccal root and root wall thickness. Root wall thickness was measured from axial CBCT slices at three critical points of the root: The most coronal part of the furcation-facing groove in the buccal root, when present, the CEJ level of the palatal root and 5 mm apically to the CEJ level of the palatal root. Vertucci Type IV configuration was the most common among all teeth, but in single-rooted teeth, Vertucci Type II was predominant. The mean thickness of the buccal root in the area of a furcation-facing groove was 1.1 (±0.2) mm, but in 39% of the cases, it was thinner than 1 mm. The mean thickness of the palatal root at 5 mm from the CEJ was 1.1 (±0.2), but in 28% of the cases, it was thinner than 1 mm. Thickness of root dentin walls of first maxillary premolars varies and may be limited at critical points in both buccal and palatal roots. In case the patient has a previous CBCT scan it may be useful for planning treatment of first maxillary premolars, in order to recognize and avoid potential risks such as furcation-facing groove, thin dentin walls in critical areas and presence of Type II Verucci canal, all of which may dictate less invasive procedures, using smaller files.

Circumferential root strains generated during lateral compaction with stainless steel vs. nickel-titanium finger spreaders.

The circumferential strains created in the radicular dentin by nickel-titanium (NiTi) and stainless steel (SS) finger spreaders (FSs) during a simulated clinical procedure of lateral compaction were compared after minimal (size 50) and extensive (size 100) canal preparations. Nineteen maxillary central incisors underwent minimal preparation, while 10 underwent an extra phase of extensive preparation. Four miniature strain gauges were bonded circumferentially in the apical third of the root (buccal, lingual, mesial, and distal). Lateral compaction was performed using either NiTi-FSs or SS-FSs. Force and strains were continuously recorded. The maximal strains (with and without normalization according to force) were recorded. The SS-FSs generated higher maximal strains normalized according to force compared with the NiTi-FSs. The maximal normalized strains were higher by 37%-43% for the mesial and distal aspects and by 6%-14% for the buccal and lingual aspects after the minimal preparation and by 24%-28% for the mesial and distal aspects and by 19%-20% for the buccal and lingual aspects after extensive preparation. The maximal normalized strains increased by 30%-70% from minimal to extensive preparations, with two teeth exhibiting vertical root fracture while compaction with SS-FS. The NiTi-FSs induce less strain in root dentin than the SS-FSs and thus may contribute less to the risk of vertical root fracture.

Effect of root morphology on the susceptibility of endodontically treated teeth to vertical root fracture: An ex-vivo model.

Vertical root fracture (VRF) of endodontically treated teeth is relatively common, and the involved teeth have a poor prognosis. Previous destructive methodologies applied force to the root in an uneven manner; thus, the associated experiments could not truly assess the mechanical behavior of VRF. This problem was resolved in the current study via the novel application of a bursting pressure methodology to endodontically treated maxillary central incisors and premolars. Hydrostatic pressure was applied inside the root canal through a cannula bonded to the coronal access cavity, and the apical foramen was sealed. VRFs were observed as water burst from the fractured root surface. Morphometric parameters were measured by staining and serially sectioning the roots. The bursting pressure was significantly lower in the premolars compared with that in the incisors (19.1±3.3MPa and 25.5. ±4.5MPa, respectively, p=0.001). Cracks in the roots appeared from the apex to the cement enamel junction (CEJ) (61%), apex to mid-root (26%) and mid-root to CEJ (13%), and they involved either two root surfaces (52%) or one root surface (48%) and closely resembled clinical VRF cases. Positive correlations were found between the bursting pressure and the proximal root wall thickness, whereas correlations were not observed between the bursting pressure and the buccal or lingual wall thicknesses. Statistical Analyses of Covariance (ANCOVA) models showed that the proximal wall thickness and an elliptically shaped root cross section were the variables that indicated the differences in strength between premolars, which are more prone to VRF, and maxillary central incisors, which are less prone to VRF.

Strain Distribution in Root Surface Dentin of Maxillary Central Incisors during Lateral Compaction.

AIM: To precisely quantify the circumferential strains created along the radicular dentin of maxillary incisors during a simulated clinical procedure of lateral compaction. METHODS: Six miniature strain gauges were bonded on the roots of fourteen recently extracted maxillary central incisors that were subjected to root canal instrumentation. The strain gauges were bonded at three levels (apical, middle, and coronal) and four aspects (buccal, lingual, mesial, and distal) of the roots. Each tooth was embedded in a PVC cylinder containing polyvinyl-siloxane impression material. Root filling was then performed by simulating the clinical procedure of lateral compaction using nickel-titanium finger spreaders. The force applied to the spreader and the strains developing in the surface root dentin were continuously recorded at a frequency of 10 Hz. RESULTS: The highest strains that developed during lateral compaction were in the mesial and distal aspects at the apical level of the root. The magnitudes of the maximal mesial/distal strains at the apical as well as the mid-root levels were approximately 2.5-3 times higher than those at the buccal/lingual aspects (p = 0.041). The strains decreased significantly (p<0.04) from the apical through the mid-root levels to the coronal level, yielding gradients of 2.5- and 6-fold, respectively. The mesial and distal strains were consistently tensile and did not differ significantly; however, the buccal strains were generally 35-65% higher than the lingual strains (p = 0.078). Lateral compaction resulted in the gradual build-up of residual strains, resulting in generation of a 'stair-step' curve. These strains declined gradually and almost completely disappeared after 1000 sec. CONCLUSIONS: With proper mounting of several miniature strain gauges at various levels and aspects of the root, significant circumferential strains can be monitored under clinically relevant compaction forces. The residual strains at the end of lateral compaction are not stored in the dentin but decrease gradually to negligible levels.

Apical extrusion of debris by supplementary files used for retreatment: An ex vivo comparative study.

AIM: This study evaluated whether using supplementary files for removing root canal filling residues after ProTaper Universal Retreatment files (RFs) increased the debris extrusion apically. MATERIALS AND METHODS: Eighty mandibular premolars with single root and canal were instrumented with ProTaper Universal rotary system (SX-F3) and obturated. The samples were divided randomly into four groups (n = 20). Group 1 served as a control; only ProTaper Universal RFs D1-D3 were used, and the extruded debris was weighed. Groups 2, 3, and 4 were the experimental groups, receiving a twofold retreatment protocol: Removal of the bulk, followed by the use of supplementary files. The bulk was removed by RFs, followed by the use of ProTaper NEXT (PTN), WaveOne (WO), and Self-Adjusting File (SAF) for removal of the remaining root filling residues. Debris extruded apically were weighed and compared to the control group. Statistical analysis was performed using one-way analysis of variance (ANOVA) and post hoc Tukey's test. RESULTS: All the three experimental groups presented significant difference (P < .01). The post hoc Tukey's test confirmed that Group 4 (SAF) exhibited significantly less (P < .01) debris extrusion between the three groups tested. CONCLUSION: SAF results in less extrusion of debris when used as supplementary file to remove root-filling residues, compared to WO and PTN.

Assessment of the fracture resistance of teeth instrumented using 2 rotary and 2 reciprocating files versus the Self-Adjusting File (SAF): An ex vivo comparative study on mandibular premolars.

AIM: Current ex vivo study compared fracture resistance of teeth instrumented using 5 endodontic files, filled with Gutta-percha and AH Plus. MATERIALS AND METHODS: Sixty freshly extracted, single-rooted mandibular premolars were acquired and decoronated to obtain 15 mm segments. These samples were randomly divided into six groups (n = 10). Group 1 served as the control containing untreated samples (without instrumentation or filling). In Groups 2-6, samples were instrumented using rotary (Universal ProTaper and Revo-S), reciprocating (WaveOne and RECIPROC(®)), and self-adjusting file (SAF), respectively. Following instrumentation, the samples were filled by lateral compaction with Gutta-percha and AH Plus. A week later, after the sealer was completely set, a vertical load was applied to the specimen's canal in each group until fracture. The loads required for fracture were recorded, and statistical analysis was performed. RESULTS: The mean fracture load differed significantly among the groups (P < 0.01; one-way ANOVA). Tukey's post-hoc tests revealed that the fracture resistance was similar in the control and SAF groups (P > 0.05) and was significantly higher than that of the 2 rotary and reciprocating groups (P < 0.01). CONCLUSION: The samples instrumented by the SAF exhibited a better fracture resistance.

The efficacy of the Self-Adjusting File versus WaveOne in removal of root filling residue that remains in oval canals after the use of ProTaper retreatment files: A cone-beam computed tomography study.

AIM: The current ex vivo study compared the efficacy of removing root fillings using ProTaper retreatment files followed by either WaveOne reciprocating file or the Self-Adjusting File (SAF). MATERIALS AND METHODS: Forty maxillary canines with single oval root canal were selected and sectioned to obtain 18-mm root segments. The root canals were instrumented with WaveOne primary files, followed by obturation using warm lateral compaction, and the sealer was allowed to fully set. The teeth were then divided into two equal groups (N = 20). Initial removal of the bulk of root filling material was performed with ProTaper retreatment files, followed by either WaveOne files (Group 1) or SAF (Group 2). Endosolv R was used as a gutta-percha softener. Preoperative and postoperative high-resolution cone-beam computed tomography (CBCT) was used to measure the volume of the root filling residue that was left after the procedure. Statistical analysis was performed using t-test. RESULTS: The mean volume of root filling residue in Group 1 was 9.4 (±0.5) mm(3), whereas in Group 2 the residue volume was 2.6 (±0.4) mm(3), (P < 0.001; t-test). CONCLUSIONS: When SAF was used after ProTaper retreatment files, significantly less root filling residue was left in the canals compared to when WaveOne was used.

The self-adjusting file instrumentation results in less debris extrusion apically when compared to WaveOne and ProTaper NEXT.

AIM: The present ex vivo study aimed to evaluate the debris extrusion after instrumenting the root canals by three different files systems. MATERIALS AND METHODS: Sixty extracted human mandibular premolars with single canals were selected and randomly divided into three groups (n = 20) for instrumentation with three different files. Group 1: WaveOne (primary) single reciprocating file (WO; Dentsply Maillefer, Ballaigues, Switzerland) (25/08), Group 2: Self-adjusting file (SAF; ReDent-Nova, Ra'anana, Israel) (1.5 mm), and Group 3: ProTaper NEXT X1 and X2 (PTN; Dentsply Tulsa Dental, Tulsa, OK) (25/06). Debris extruding by instrumentation were collected into pre-weighed Eppendorf tubes. These tubes were then stored in an incubator at 70°C for 5 days. The tubes were then weighed to obtain the final weight, with the extruded debris. Statistical analysis for the debris extruded apically was performed using one-way analysis of variance and post hoc Tukey's test. RESULTS: The statistical analysis showed a significant difference between all the three groups tested (P < 0.01). The following post hoc Tukey's test confirmed that Group 2 (SAF) exhibited significantly least (P < 0.01) debris extrusion between the three groups tested. CONCLUSIONS: The SAF resulted in significantly less extrusion of debris when compared to reciprocating WO and rotary PTN.

The self-adjusting file (SAF) system: An evidence-based update.

Current rotary file systems are effective tools. Nevertheless, they have two main shortcomings: They are unable to effectively clean and shape oval canals and depend too much on the irrigant to do the cleaning, which is an unrealistic illusionThey may jeopardize the long-term survival of the tooth via unnecessary, excessive removal of sound dentin and creation of micro-cracks in the remaining root dentin. The new Self-adjusting File (SAF) technology uses a hollow, compressible NiTi file, with no central metal core, through which a continuous flow of irrigant is provided throughout the procedure. The SAF technology allows for effective cleaning of all root canals including oval canals, thus allowing for the effective disinfection and obturation of all canal morphologies. This technology uses a new concept of cleaning and shaping in which a uniform layer of dentin is removed from around the entire perimeter of the root canal, thus avoiding unnecessary excessive removal of sound dentin. Furthermore, the mode of action used by this file system does not apply the machining of all root canals to a circular bore, as do all other rotary file systems, and does not cause micro-cracks in the remaining root dentin. The new SAF technology allows for a new concept in cleaning and shaping root canals: Minimally Invasive 3D Endodontics.

From files to SAF: 3D endodontic treatment is possible at last.

3D cleaning, shaping and obturation of root canals has always been the desired goal of endodontic treatment which in many cases is difficult to attain. The introduction of NiTi rotary files made a major change in endodontic practice, making treatment easier, safer and faster. Nevertheless, after 16 years of intensive development, most of these instruments still share several drawbacks, the major one being the inability to three-dimensionally clean and shape oval root canals. The Self-Adjusting File (SAF) System was designed to overcome many of the current drawbacks of rotary file systems. It is based on a hollow, highly compressible file that adapts itself three-dimensionally to the shape of a given root canal, including its cross section. The file is operated with vibratory in-and-out motion, with continuous irrigation delivered by a peristaltic pump through the hollow file. A uniform layer of dentin is removed from the whole circumference of the root canal, thus achieving the main goals of root canal treatment while preserving the remaining root dentin. The 3D scrubbing effect of the file, combined with the always fresh irrigant, result in unprecedentedly clean canals which facilitate in turn better obturation. More effective disinfection of flat-oval root canals is another goal which is simultaneously attained. The safety of the root-canal treatment is also greatly enhanced by the high mechanical stability of the SAF and by using a new concept of no-pressure irrigation. The SAF System gets the operator much closer to the long-desired goal of 3D root-canal treatment.