Tagger's Hybrid Research Articles

Regressão de lesão periapical após tratamento não cirúrgico – Relato de caso

The present study aims to present the clinical case report regarding non-surgical endodontic treatment performed on tooth 22, with diffuse periapical lesion, suggesting chronic dento-alveolar abscess. The methodology consists of an individual descriptive study of the case report type, which includes radiographic images of a 23-year-old female patient. Clinically, in addition to swelling, it was found that there was mobility, absence of pain in the thermal test (cold) and on palpation. After a complete clinical examination, endodontic treatment, coronary opening, root canal exploration, and root canal preparation were initiated using the modified Oregon crown-apex preparation technique, associated with 2.5% sodium hypochlorite as an irrigating solution. Calcium hydroxide paste was applied as an intracanal medication for a period of 30 days and the coronary access was sealed with glass ionomer. In the following session, after verifying the absence of clinical signs and symptoms, it was decided to fill the root canal using the Tagger's Hybrid technique associated with gutta-percha and AH Plus endodontic cement. After the 24-month preservation period, tissue repair and bone neoformation of the area were observed, as well as the absence of clinical signs.

Quality analysis of four filling techniques in ovoid root canals prepared with M® instruments

Aims: This study aimed to assess the quality of various filling techniques in ovoid root canals prepared using M® instruments. Materials and Methods: Sixty ovoid root canals underwent endodontic treatment with M® instruments and were subsequently divided randomly into four experimental groups, each employing a different obturation technique: TU - single cone; TL - active lateral condensation; TH - Tagger hybrid; TS - Schilder technique. Digital radiographs were taken in both mesiodistal and buccolingual directions to examine the filled teeth. The percentage of filling material and empty spaces was quantified using Photoshop® software. Data were subjected to statistical analysis using the one-way ANOVA test and T test (? = 0.05). Results: In the TL and TS groups, there was a significantly lower average percentage of unfilled spaces compared to the TU and TH groups (P<0.0001). When analyzing the radiographic directions, the mesiodistal view exhibited the highest mean percentage of unfilled spaces, with differences in filling quality observed only in the TU and TL groups. Conclusions: Active lateral condensation and Schilder techniques demonstrated superior performance in achieving effective filling of ovoid root canals.

Evaluation of the Ability of 3 Reciprocating Instruments to Remove Obturation Material: A Micro–Computed Tomography Study

IntroductionThe purpose of this study was to evaluate the ability of the Reciproc, Reciproc Blue, and WaveOne Gold systems to remove filling material during endodontic retreatment of extracted human mandibular premolars. MethodsThirty-nine teeth were instrumented with the Protaper Universal System to the F3 file and filled with the Tagger hybrid technique using an F3 gutta-percha cone and AH Plus cement. At the end of this period, the teeth were scanned with micro–computed tomography before and after removal of the filling material from the root canals. The teeth were divided into 3 groups (n = 13) based on the apical volume, depending on the systems used to remove the filling material. Group GR: Reciproc 40/.06; Group GRB: Reciproc Blue 40/.06; and Group GWG: WaveOne Gold 35/.06. The results were statistically analyzed using the tests of Kruskal-Wallis, Duncan, and analysis of variance at a significance level of 5%. ResultsThe results showed that there were no significant differences between the amounts of filling material removed, either for the apical and middle regions alone or in the overall evaluation for the 3 groups (P = .97). The time evaluation statistically showed that the GR and GWG groups required less time to clean the root canals than the GRB group. ConclusionsReciproc R40 files and WaveOne Gold Medium files required less time for endodontic treatment than Reciproc Blue R40 files. There was no difference in the ability to remove obturation material between the 3 instruments. No instrument was able to completely remove the filling material from the root canals.

Marginal gaps and voids using two warm compaction techniques and different sealers: a micro-CT study.

To assess the percentage of marginal gaps and voids in oval-shaped canals obturated by using two warm compaction techniques with a Bio-C sealer and AH Plus Jet. Forty canines with oval canals were scanned by microcomputed tomography (micro-CT), and root canal preparation was performed with an XP-endo Shaper system and irrigated with 5.25% sodium hypochlorite. Then, the specimens were paired into four groups (n=10) according to the root canal filling technique and endodontic sealer: Bio-C sealer and continuous wave of condensation, Bio-C sealer and Tagger's hybrid, AH Plus Jet and continuous wave of condensation, and AH Plus Jet and Tagger's hybrid. After root canal filling, a new scan was performed. The percentage of marginal gaps and voids was calculated with the ImageJ software, and the data were analyzed statistically using two-way ANOVA and Tukey tests, with a significance level of 5%. The percentage of marginal gaps was significantly lower in the Bio-C sealer than in AH Plus Jet (p=0.021) regardless of the technique. However, no difference was found in the percentage of voids between root canal filling techniques and the endodontic sealer (p>0.05). Both sealers and techniques demonstrated good quality of root canal filling. However, the use of the Bio-C sealer enhanced the filling ability by reducing marginal gaps, regardless of the root canal filling technique. This study highlights the better performance of the Bio-C sealer in the quality of the root canal filling, reducing marginal gaps when compared to AH Plus Jet independent of the technique.

Effect of intra-radicular cleaning protocols after post-space preparation on marginal adaptation of a luting agent to root dentin.

To evaluate the effect of intra-radicular cleaning protocols after post-space preparation (PSP) on marginal adaptation of a luting agent to root dentin. Eighty bovine incisors were sectioned transversely to obtain 18-mm-long root sections. The roots were prepared with ProTaper instruments and filled using Tagger's hybrid technique. PSP was performed at a length of 14 mm using #3-5 Largo drills. The roots were distributed into eight groups according to the chelating solution used (17% EDTA or 0.2% Chitosan) and the chelating activation/delivery method employed (conventional needle irrigation [CNI], EndoActivator [EA], XP-Endo Finisher [XPF] or passive ultrasonic irrigation [PUI]). The fiber posts were cemented using self-adhesive resin cement, and the roots were sectioned to obtain three discs from each root third. The dentin discs were observed under an optical microscope at ×40 magnification to assess marginal adaptation. The different protocols were compared considering the frequency of the marginal adaptation scores using the Kruskal-Wallis test, followed by the Dwass-Steel-Critchlow-Fligner test (α = 5%). The use of 17% EDTA resulted in better marginal adaptation (P < 0.001). PUI yielded results that were similar to those for EA (P = 0.949) and superior to those for XPF (P = 0.020). The combination of 17% EDTA + PUI provided a greater number of interfaces without marginal gaps (P < 0.001). The cleaning protocol influenced the marginal adaptation of resin cement to root dentin.

Effectiveness of endodontic retreatment using WaveOne Primary files in reciprocating and rotary motions.

This study evaluated the efficiency of WaveOne Primary files (Dentsply Sirona) for removing root canal fillings with 2 types of movement: reciprocating (RCP) and continuous counterclockwise rotation (CCR). Twenty mandibular incisors were prepared with a RCP instrument (25.08) and filled using the Tagger hybrid obturation technique. The teeth were retreated with a WaveOne Primary file and randomly allocated to 2 experimental retreatment groups (n = 10) according to movement type: RCP and CCR. The root canals were emptied of filling material in the first 3 steps of insertion, until reaching the working length. The timing of retreatment and procedure errors were recorded for all samples. The specimens were scanned before and after the retreatment procedure with micro-computed tomography to calculate the percentage and volume (mm3) of the residual filling material. The results were statistically evaluated using paired and independent t-tests, with a significance level set at 5%. No significant difference was found in the timing of filling removal between the groups, with a mean of 322 seconds (RCP) and 327 seconds (CCR) (p < 0.05). There were 6 instrument fractures: 1 in a RCP motion file and 5 in continuous rotation files. The volumes of residual filling material were similar (9.94% for RCP and 15.94% for CCR; p > 0.05). The WaveOne Primary files used in retreatment performed similarly in both RCP and CCR movements. Neither movement type completely removed the obturation material, but the RCP movement provided greater safety.

Influence of root canal moisture conditions on the bond strength of endodontic sealers to dentin

Objective: To investigate the influence of intraradicular moisture conditions on the bond strength of 3 different endodontic cements in the coronal, middle, and apical thirds of the root canal. Materials and Methods: 90 single-rooted teeth were instrumented with a reciprocal R#50 file and randomly divided into 3 experimental groups: Dry group: dry canals with absorbent paper tips; Moist group: suction syringe and capillary tip coupled to a vacuum pump; Wet group: aspiration with endodontic suction. The groups were divided according to the endodontic sealer used: AH plus (Denstply), Hiflow (Brasseler) and Bio-c Sealer (Angelus). Obturation was performed using Tagger's hybrid technique with a single cone. The teeth were subjected to the "push-out" test to evaluate the bond strength of the cements. Results: Data were analyzed using the Kolgomorov-Smirnoff normal distribution test and the Mann Whitney U test to compare means within and between groups. The standard error established was 5% at a significance level of 95%. AH plus showed better results regardless of canal moisture conditions. Hiflow showed better bond strength in the dry group compared to the moist group (p=0.023) in the cervical area. Bio-C Sealer showed no statistically significant differences (p &gt; 0.05). Conclusion: Moisture conditions affected the bond strength values of endodontic cements. The prevalence of failure moduli was mixed in all root thirds, regardless of the cement used.

Ex Vivo Evaluation of Bacterial Leakage and Coronal Sealing Capacity of Six Materials in Endodontically Treated Teeth.

Successful endodontic treatment requires an effective coronal sealing to prevent the penetration of saliva and microorganisms into the root canal system. We aimed to investigate the sealing capacity of Maxxion R, Intermediate Restorative Material (IRM), Mineral Trioxide Aggregate-like material (Biodentine), White Cimpat, Flow Resin and Z250 Resin against Enterococcus (E.) faecalis infiltrates, when used as coronal sealants after endodontic treatment. Sixty-six roots of adult lower premolars were randomly divided into 6 experimental groups with 10 roots each (n=10), and two control groups (positive and negative) with three roots each. The root canals were instrumented to ProTaper F3 file, irrigated with 2.5% NaOCl and 17% EDTA, and filled using Tagger's Hybrid technique with AH-Plus cement. After removing 2 mm of the coronal third filling with a Gates Glidden #6 drill, the cervical portion of each of the sixty roots was sealed with a 2 mm-thick plug, plus the respective material being tested in this study. All roots were fitted to silicone devices (Eppendorf) with cut extremities and sterilized with ethylene oxide; experimental procedures were performed in a laminar flow chamber for aseptic chain maintenance. All specimens were inoculated with E. faecalis, and the culture medium was renewed every 3 days for 60 days. Medium turbidity was evaluated daily. The obtained data were subsequently submitted to analysis of variance (ANOVA-R) complemented by Student's t-test at a significance level of 5%. Analyzes of variance were calculated using the SAS system GLIMMIX procedure. Biodentine (56.90), Z250 Resin (54.90) and White Cimpat (53.30) resisted contamination for a longer time compared to Maxxion R (51.30), Flow Resin (50.70), and IRM (48.70) over a period of 60 days. Biodentine, Resin Z 250 and White Cimpat presented the lowest infiltration averages when compared to the other tested materials.

Postoperative pain after endodontic treatment of necrotic teeth submitted to large apical preparation using oscillatory kinematics.

BackgroundRegardless of the technique applied for chemomechanical preparation, postoperative pain is a very relevant matter in endodontics. Objective: To evaluate postoperative pain after endodontic treatment of necrotic teeth submitted to large apical preparation (LAP) using oscillatory kinematics. Material and MethodsThe sample included 60 asymptomatic necrotic teeth with or without apical radiolucency, and with normal periodontal status, referred for endodontic treatment. Following initial procedures, the position and approximate size of the apical constriction were determined by using an apex locator and K Flexofiles, respectively. The chemomechanical preparation was conducted using oscillatory kinematics and 2.5ml of 2.5% NaOCl at each file change to achieve LAP, and the filling was done with Tagger’s hybrid technique and EndoFill sealer. Phone calls were made to all the patients at 24, 48 and 72 hours after treatment to request their classification of postoperative pain, and data were submitted to statistical analysis. ResultsOnly 3 patients (5%) reported severe pain after 72 hours. Moderate pain was reported by 17, 9 and 1 patient after 24, 48 and 72 hours, respectively (P = 0.000). However, paired analyses showed a statistically significant difference only between 24 and 72 hours (P = 0.001), and 48 and 72 hours (P = 0.014). Age and tooth type did not influence the postoperative pain, regardless of time (P> 0.05). After 72 hours, women experienced significantly more pain than men (P = 0.012), and teeth without periradicular lesion were more sensitive that teeth with perirradicular lesion (P = 0.027). ConclusionsAcute or moderate postoperative pain was uncommon after endodontic treatment of necrotic teeth submitted to LAP using oscillatory kinematics. Key words:Endodontic treatment, oscillatory kinematics, postoperative pain, pulp necrosis.

Influence of different obturation techniques in coronal bacterial infiltration: study in dogs

The objective of this study was to evaluate, in vivo, coronal bacterial infiltration after endodontic treatment with different obturation technique. Forty-five dogs’ root canals, originated from incisors and premolars, were used. The animals were intubated after general anesthesia. After local antisepsis and placement of rubber dam isolation, teeth were opened and instrumented up to a Kerr handfile #40, followed by three obturation protocols with Endofill®: Lateral condensation, Lateral condensation with a coronal plug of set Endofill® and Tagger hybrid technique. Access openings were not sealed and root fillings remained exposed to oral environment for 90 days. After this period, animals were euthanized and specimens were histologically processed and stained with Brown and Brenn. Dentinal tubules were evaluated with presence or absence of bacteria descriptive analysis. Bacterial infiltration was identified on root canal walls in six out of 14 root canals filled with the lateral condensation technique (42,8%), two out of 15 canals filled with Lateral condensation with a plug of set Endofill® (13,3%) and in two out 13 root canals filled with the Tagger hybrid technique (15,3%). Although the use of a coronal plug or a thermomechanical compaction technique showed less bacterial infiltration than conventional lateral condensation, none of the obturation techniques prevented bacterial infiltration to periapical area, evidencing the importance of a proper coronal seal or final restoration.

Postoperative pain after endodontic treatment of necrotic teeth with large intentional foraminal enlargement

ObjectivesTo evaluate postoperative pain after endodontic treatment of necrotic teeth using large intentional foraminal enlargement (LIFE).Materials and MethodsThe sample included 60 asymptomatic necrotic teeth (with or without chronic apical periodontitis), and a periodontal probing depth of 3 mm, previously accessed and referred to perform endodontic treatment. After previous procedures, the position and approximate size of the apical foramen (AF) were determined by using an apex locator and K flexo-files, respectively. The chemomechanical preparation was performed with Profile 04 files 2 mm beyond the AF to achieve the LIFE, using 2.5 mL of 2.5% NaOCl at each file change. The filling was performed by Tagger's hybrid technique and EndoFill sealer. Phone calls were made to all the patients at 24, 48 and 72 hours after treatment, to classify postoperative pain. Statistical analysis was performed by different tests with a significance level of 5%.ResultsAge, gender, periradicular status and tooth type did not influence postoperative pain (p > 0.05). Only 1 patient (1.66%) reported severe pain after 72 hours. Moderate pain was reported by 7, 4 and 3 patients after 24, 48 and 72 hours, respectively (p = 0.0001). However, paired analyses showed a statistically significant difference only between 24 and 72 hours (p = 0.04). Sealer extrusion did not influence the postoperative pain (p > 0.05).ConclusionsAcute or moderate postoperative pain was uncommon after endodontic treatment of necrotic teeth with LIFE.Trial RegistrationThe Brazilian Clinical Trials Registry Identifier: RBR-3r967t

Sucesso no tratamento endodôntico em incisivo lateral superior com reabsorção radicular interna inflamatória não perfurante: relato de caso

As reabsorções dentárias internas são geralmente assintomáticas e quase sempre diagnosticadas em exames radiográficos de rotina. O objetivo deste estudo é apresentar um relato de caso clínico de um dente acometido por reabsorção radicular interna inflamatória não perfurante, com intuito de divulgar informações que sirvam de subsídios para orientar os profissionais frente a esses casos, auxiliando na conduta terapêutica. Paciente do sexo feminino, 53 anos de idade, foi encaminhada ao curso de especialização da Faculdade CIODONTO após realização de um exame radiográfico periapical de rotina, o qual mostrou reabsorção interna não perfurante à nível de terço médio radicular do dente 12. Radiograficamente foi verificado que o contorno dos limites pulpares sofre uma expansão relativamente simétrica de aspecto balonizante, contornos regulares e arredondados. Após a abertura coronária, foi observado sangramento compatível à polpa vital, irrigando-se, inicialmente, com água de Cal. O preparo biomecânico pela técnica coroa-ápice sem pressão foi realizado e como medicação intracanal foi selecionado o Callen por 30 dias e pasta L&amp;C por 90 dias. Após esse período, foi realizada a obturação dos canais radiculares pela técnica termoplástica híbrida de Tagger e cimento endodôntico à base de hidróxido de cálcio. A proservação foi realizada após 1 ano e o sucesso da terapia endodôntica foi constatado. Dessa forma, de acordo com o protocolo indicado na literatura é permitida a resolução clínica efetiva de dentes acometidos por reabsorção interna não perfurante, mostrando-se uma ótima alternativa de tratamento conservador.

Photodynamic therapy as an aiding in the endodontic treatment: case report

ABSTRACT This article describes the application of Photodynamic Therapy as an aid to the endodontic treatment performed on a permanent tooth iatrogenically perforated and with pulp necrosis. After clinical and radiographic examination, the coronary access, curettage of the drilling area and mechanized preparation with the Reciproc System were performed. The drilling area was sealed with Mineral Trioxide Aggregate after prior alkalinization and decontamination by a calcium hydroxide buffer. After successive intracanal medication changes, the remission of the fistula, a clinical sign of endodontic infection, was not observed. Photodynamic therapy was then performed to reduce bacterial load in the root canal system, which resulted in fistula suppression. Then, it was possible to end the treatment with the obturation of the ducts by the Tagger Hybrid thermomechanical technique. After a year of proservation, the tooth presents no symptomatology and it is concluded that the Photodynamic Therapy was an effective solution in this case.

Cleaning Ability of Irrigants and Orange Oil Solvent Combination in the Removal of Root Canal Filling Materials.

Objective:This study investigated the influence of different irrigants and the use of orange oil solvent in the removal of filling materials during root canal retreatment.Methods:Forty maxillary premolars were shaped using the ProTaper System up to file F3 (size 30, 0.09 taper) and filled by Tagger’s hybrid technique using the AH Plus. Samples were randomly assigned to four groups (n=10) according to the irrigating protocol during endodontic retreatment with the ProTaper Universal Re-treatment System: G1, 2% chlorhexidine (CHX) gel; G2, 2% CHX gel with an orange oil solvent; G3, 5% sodium hypochlorite (NaOCl); and G4, 5% NaOCl with an orange oil solvent. Afterwards, the samples were longitu-dinally split into two halves, and the root wall images were prepared by scanning electron microscopy. Two pre-calibrated evaluators analyzed the images using a filling materials remnants score system. Data were statistically analyzed using the Kruskal–Wallis and Dunn’s tests (p<0.05).Results:All samples had residual filling materials in the root canal walls after instrumentation. According to the presence of the filling material remnants in the total area of samples, the groups were ranked in the follow-ing order: G2=G4>G1=G3. No statistical differences were found when the CHX and NaOCl were used (p>0.05). Groups in which a solvent was used showed a less effective cleaning ability (p<0.05). The use of NaOCl with solvent presented the highest amounts of filling materials remnants in the critical apical area (p<0.05).Conclusion:The use of orange oil with NaOCl or CHX does not improve the removal of residual root canal filling materials.

Micro-computed tomography assessment of different obturation techniques for filling lateral canals.

BackgroundThe aim of this study was to evaluate obturation depth and volume by means of micro-CT when filling lateral canals.Material and MethodsThirty single-rooted teeth were used. After instrumentation, three artificial lateral canals were created on each mesial and distal surface (one on each third). The samples were then separated randomly into three groups according to the obturation technique used (n=10): lateral condensation (Group 1), Tagger’s hybrid technique (Group 2) and GuttaCore™ (Group 3). Samples were scanned and data was processed with Avizo software. Depth and volume of the infilling were measured in each lateral canal. Values were expressed as percentages and were analyzed using the Kruskal-Wallis test.ResultsMean depth showed statistically significant differences between Group 3 and Groups 1 (p=0.001) and 2 (p=0.003), whereas no significant difference was found between Groups 1 and 2 (p≈1). As for mean volume, significant differences were found between Group 3 and Groups 1 (p=0.01) and 2 (p=0.003) but no differences were found between Groups 1 and 2 (p=1.00).ConclusionsGuttaCore provided the best lateral canal sealing among the three techniques compared. Key words:Lateral canals, Micro-CT, obturation.

Regaining Apical Patency with Manual and Reciprocating Instrumentation during Retreatment.

Introduction:Different techniques have been proposed to help achieving apical patency during endodontic treatment and retreatment. The objective of this in vitro study was to compare reestablishment of apical patency in teeth previously subjected to root canal treatment using manual and reciprocating instruments. Methods and Materials:A total of 40 single-rooted extracted human mandibular incisors were selected and prepared using the Hero 642 sequence to 45/0.02 and obturated using Tagger’s hybrid technique to 1 mm short of the apex. Teeth were divided into two groups according to the type of instrument used to regain patency: group 1, hand K-files and group 2, reciprocating WaveOne Primary files (25/0.08). Fisher’s exact test was used in the statistical analysis. Result: In group1, apical patency was regained in 9 of the 20 teeth tested (46%), compared to 20 teeth (100%) in group 2. The difference between the groups was significant (P<0.0001). Conclusion:Our study shows that reciprocating instrumentation is more successful in regaining apical patency in single-rooted, previously treated teeth.

Influence of Root Canal Filling Techniques on Sealer Penetration and Bond Strength to Dentin.

The influence of root canal filling techniques on the penetration of AH Plus into dentinal tubules was evaluated using confocal laser scanning microscopy (CLSM) and the impact on the bond strength of the filling material on the root dentin was evaluated using the push-out test. Roots of the maxillary central incisors (n=40) were prepared with ProTaper Universal and assigned to four groups: lateral condensation, vertical compaction, modified Tagger hybrid and single cone. After root canal filling with gutta-percha and AH Plus, along with the addition of 0.01% fluorescein, the roots were cut into 2-mm slices. CLSM was performed on the first slice of each root third, followed by the push-out test. The second slice was analyzed under SEM. ANOVA demonstrated a statistically significant difference between the root canal filling techniques and the root thirds (p<0.05). For percent penetration, Tukey's test showed that the vertical compaction (91.77±13.51), lateral condensation (89.18±10.91) and modified Tagger hybrid (87.53±15.42) presented the highest values, which significantly differed (p<0.05) from those of the single cone (78.19±22.46). For bond strength (MPa), lateral condensation (3.42±0.54) and vertical compaction (3.47±0.53) had the highest values (p<0.05), while the modified Tagger hybrid (2.19±0.41) and single cone (0.54±0.21) had the lowest. In conclusion, the lateral condensation, vertical compaction and Modified Tagger's hybrid techniques resulted in greater penetration and bond strength to the intra-radicular dentin.

Evaluation of three root canal filling techniques through digital radiograph

Endodontic obturation consists of root canal filling by antiseptic or inert materials that promote a three-dimensional sealing and stimulate the repair process without interfering with it. Different obturation techniques and materials have been proposed to meet this requirement. Objective: To compare the root canal filling promoted by lateral condensation technique, Tagger's hybrid technique and McSpadden technique by assessing the filling quality through digital radiograph. Material and methods: A total of 45 extracted single-rooted human teeth were used and randomly divided into three experimental groups. After instrumentation, the teeth were filled by lateral condensation (n=15), Hybrid Tagger (n=15), and McSpadden techniques (n=15). Then, digital radiographs were taken with projected increased 10 times, at mesial-distal and buccolingual directions. Results: Visually, few empty spaces were detected at the three root thirds of teeth filled by different techniques. However, statistical analysis (Kruskal-Wallis) found no differences among the different groups, neither among the different thirds nor between both incidences evaluated. Conclusion: It was concluded that the three obturation techniques exhibited similar behavior in relation to the sealing of the root canal through digital radiograph.

Root Canal Filling: Fracture Strength of Fiber-Reinforced Composite-Restored Roots and Finite Element Analysis

The aims of this study were to evaluate the effect of root canal filling techniques on root fracture resistance and to analyze, by finite element analysis (FEA), the expansion of the endodontic sealer in two different root canal techniques. Thirty single-rooted human teeth were instrumented with rotary files to a standardized working length of 14 mm. The specimens were embedded in acrylic resin using plastic cylinders as molds, and allocated into 3 groups (n=10): G(lateral) - lateral condensation; G(single-cone) - single cone; G(tagger) - Tagger's hybrid technique. The root canals were prepared to a length of 11 mm with the #3 preparation bur of a tapered glass fiber-reinforced composite post system. All roots received glass fiber posts, which were adhesively cemented and a composite resin core was built. All groups were subjected to a fracture strength test (1 mm/min, 45°). Data were analyzed statistically by one-way ANOVA with a significance level of 5%. FEA was performed using two models: one simulated lateral condensation and Tagger's hybrid technique, and the other one simulated the single-cone technique. The second model was designed with an amount of gutta-percha two times smaller and a sealer layer two times thicker than the first model. The results were analyzed using von Mises stress criteria. One-way ANOVA indicated that the root canal filling technique affected the fracture strength (p=0.004). The G(lateral) and G(tagger) produced similar fracture strength values, while G(single-cone) showed the lowest values. The FEA showed that the single-cone model generated higher stress in the root canal walls. Sealer thickness seems to influence the fracture strength of restored endodontically treated teeth.

Effectiveness of different obturation techniques in surpassing the ledge formed in simulated curved canals

AIM: To compare the effectiveness of different obturation techniques in surpassing the ledge formed in simulated curved root canals. METHODS: Eighty acrylic-resin blocks with curved canals were instrumented with Gates-Glidden drills to simulate a ledge formation. Then, a K-File #10 was used for trying to surpass the deviation, and the blocks that permitted surpassing were rejected. The remaining blocks were divided into 4 groups according to the obturation technique: lateral condensation, Tagger's Hybrid technique, Thermafil and System B. The blocks had their images digitalized using a scanner before and after the obturation procedures. The images were analyzed with Image Tool 3.0 software. Statistical analysis was performed by one-way ANOVA at a significant level of 5%. RESULTS: The System B resulted in the highest obturated area (p<0.001). There were no significant differences between the Tagger's Hybrid technique and Thermafil system regarding the effectiveness in surpassing ledge (p>0.05). The lateral condensation resulted in the worst ability in filling the ledge space (p<0.001). CONCLUSIONS: Within the limitations of this study, it was possible to conclude that techniques using heat condensation or gutta-percha thermoplastification were more effective in surpassing the ledge formed in curved canals than the lateral condensation.