Third Of Root Research Articles

Evaluation of 17% EDTA and 10% citric acid in smear layer removal and tubular dentin sealer penetration.

The purpose of this study was to compare the efficacy of different chelating solutions (17% EDTA and 10% citric acid) on the smear layer removal, and their effect on tubular dentin sealer penetration. Sixty root canals were prepared and distributed into four groups (n = 15) according to the final irrigation protocol: G1, final irrigation with 2.5 mL of distilled water; G2, final irrigation with 2.5 mL of 2.5% sodium hypochlorite solution; G3, final irrigation with 2.5 mL of 17% EDTA; and G4, final irrigation with 2.5 mL of 10% citric acid. Five specimens from each group were not filled to assess smear layer removal by scanning electron microscopy. Ten specimens from each group were filled for analysis of sealer penetration into dentinal tubules by confocal laser scanning microscopy. Smear layer removal (Kruskal-Wallis and Dunn's tests) and sealer penetration (F and Tukey's tests) were statistically analyzed with 95% of significance level. G3 and G4 had greater smear layer removal rates in the cervical and middle thirds, in comparison with G1 and G2 (p < .05). G3 and G4 had the highest percentages of sealer penetration in all thirds, in comparison with G1 and G2 (p < .05). Smear layer removal was effective only at the cervical and middle thirds when the chelating solutions were used. Sealer penetration into the dentinal tubules significantly increased in all root thirds when the specimens were treated with both chelating solutions.

Differences in distances between maxillary posterior root apices and the sinus floor according to skeletal pattern.

The aim of this study was to evaluate the distances from the maxillary posterior root apices to the inferior wall of the maxillary sinus using cone-beam computed tomography images and the relationships between roots and maxillary sinus according to age, sex, and skeletal pattern. Three-dimensional images of each root were checked, and the distances were measured along the true vertical axis from the apex of the root to the sinus floor in 118 patients (63 male, 55 female) aged 10 to 28years. Compare-means statistic tests were done to assess the differences between groups classified according to age, sex, and skeletal pattern. The frequency of root contact with the sinus floor increased from 70% at the second premolar to more than 80% at the buccal roots of the first and secondmolars. Male and older age (20-28years) groups had significantly smaller distances or more protrusion of the root into the sinus than female and younger age (10-20years) groups. The distances were shorter, or there was more protrusion of the root into the sinus in the hyperdivergent, down-canted palatal plane, and large gonial angle groups. Male, older age, hyperdivergent skeletal pattern, and large gonial angle groups had significantly closer distances between maxillary root tips and the sinus floor or more protrusion of the roots into the sinus. The intrusion of the maxillary molars in those situations may be difficult and slow because of the pneumatized maxillary sinus.

In vitro bond strength of an epoxy resin-based root canal sealer to root dentin irradiated with high-power lasers and adhesive interface analyses.

The aim of this study was to evaluate in vitro the influence of high-power lasers (Nd:YAG and diode 980nm) associated with mineral coal as fotopotencializer on bond strength of an epoxy resin-based root canal sealer to root dentin, using the pushout test, and on the dentin/filling material interface, using confocal laser microscopy. For this purposes, 50 canines were instrumented with Mtwo rotary system up to #50.04 instrument and randomly assigned to five groups (n=10): group I-control EDTAC; group II-EDTAC and Nd:YAG laser; group III-EDTAC and diode laser 980nm; group IV-EDTAC, Nd:YAG laser and mineral coal 5g/100mL; and group V-EDTAC, diode laser 980nm and mineral coal 5g/100mL. All data were analyzed by ANOVA (at 5% significance level) following the Kruskal-Wallis, Dunn and Tukey tests. The group I increased more bond strength of the sealer to root dentin that treated with only EDTAC 17% (17.21±21.75MPa), similar to the group II (12.21±18.20MPa) and group IV (14.92±28.06MPa), both treated with Nd:YAG laser, with the exception of group IV, which was added to mineral coal. The group V (8.75±13.42MPa) had similar results to the groups II and IV, but the same similarity were found when compared with group III (7.11+11.28MPa), with lower results. Regarding the root thirds, the apical third (23.27±29.21MPa) presented a statistically higher value on bond strength than the cervical third (5.92±5.33MPa) and middle third (6.93±7, 11MPa) (p>0.05). Group II (86.27μm) showed the highest tags penetration values, with a statistically difference to the group III (51.57μm), IV (36.77μm) and V (32.37μm) (p<0.05). Group I (71.63μm) was statistically similar to groups II and III (p>0.05). Group IV had the lowest values and was statistically similarity to groups III and V (p>0.05). It was concluded that the treatment with Nd:YAG laser provides better results than the diode 980nm laser, except when was added mineral coal. The control and diode 980nm laser groups presented less adhesive failures and more mists failures than the other groups. Both lasers did not interfere negatively compared to the control group.

Wear profile of canal wall surfaces and bond strength of endodontic sealers after insitu acid challenge.

To evaluate the wear of root wall surfaces, the bond strength of sealers to dentine and the demineralization around root filling materials after canals were exposed to acid challenge in situ. Eighty-seven roots of mandibular incisors were selected. Thirty-two were used in the laboratory bond strength study (n=8), and 55 in the insitu study (n=11). Root canals were prepared biomechanically and then filled with gutta-percha and AH Plus, MTA Fillapex, Sealapex or Endofill. For 14days, 11 participants used intra-oral devices with five sterilized roots (four experimental and one control - only canal prepared). Drops of sucrose were dripped onto roots allowing the accumulation of biofilm on canal surfaces. Roots were removed, sectioned and analysed for the following: bond strength of filling material using a push-out test and also wear profile and dentine demineralization using confocal microscopy. Bond strength (MPa) was evaluated by two-way anova and Tukey test (α=0.05), and wear profile was assessed by Kruskal-Wallis and t-tests (α=0.05). AH Plus had the highest bond strength values. Intermediate results were found in roots with MTA Fillapex and Endofill, whilst Sealapex had inferior results (P<0.05). No significant differences were found amongst root thirds (P>0.05). For wear profile, samples were associated with degradation of the filling materials after exposure to the oral environment (P<0.05). Roots had signs of demineralization around the filling material when Sealapex and Endofill were used. Sealers were not able to prevent degradation of the adhesive interface and dentine. AH Plus and MTA Fillapex had superior bond strength to dentine and less intense demineralization around the root filling.

Cemental tear: To know what we have neglected in dental practice.

Cemental tear is a special kind of root surface fracture, contributing to periodontal and periapical breakdown. However, it is a challenge for doctors to diagnose, resulting in delayed or improper treatment. We reviewed the predisposing factors, location, radiographic/clinical characteristics, diagnosis and treatments of cemental tears. From the literature, patients with cemental tear were mainly males, over 60 year-old. Possible predisposing factors include gender, age, tooth type, traumatic occlusal force and vital teeth. Cemental tears were common in upper and lower anterior teeth, single or multiple, and can be present in cervical, middle and apical third of roots. Morphology of cemental tears can be either piece-shaped or U-shaped. Clinically, cemental tear shows a unitary periodontal pocket and signs/symptoms mimicking localized periodontitis, apical periodontitis and vertical root fractures. Treatment of cemental tears include scaling, root planning, root canal treatment, periodontal/periapical surgery, guided tissue regeneration, bone grafting, and intentional replantation. Recurrence of cemental tear is possible especially when the fracture involves root apex. Extraction is recommended for teeth with poor prognosis. In conclusion, cemental tears can involve both periodontal and periapical area. Dentists should understand the predisposing factors and clinical features of cemental tears for early diagnosis/treatment to prevent bone loss/tooth extraction.

Cleaning and Shaping Oval Canals with 3 Instrumentation Systems: A Correlative Micro–computed Tomographic and Histologic Study

IntroductionThe present study evaluated the cleaning and shaping ability of 3 instrumentation systems in oval canals of extracted vital teeth using a correlative analytic approach. MethodsOval distal canals from 33 freshly extracted mandibular molars with pulp vitality were scanned by micro–computed tomographic (micro-CT) imaging for sample selection. Specimens matched by anatomic similarities were distributed into 3 experimental groups according to the instrument system to be evaluated: the Self-Adjusting File (SAF; ReDentNOVA, Ra'anana, Israel), TRUShape (Dentsply Sirona, Tulsa, OK), and XP-endo Shaper (FKG Dentaire, La Chaux-de-Fonds, Switzerland). The irrigant was 5.25% sodium hypochlorite heated at 37°C. After rescanning with micro-CT imaging, the unprepared surface areas were identified, measured, and then histologically evaluated for the amount of pulp remnants in each root third. ResultsWhen the apical 4-mm canal segment was evaluated, the SAF exhibited significantly less unprepared areas than the XP-endo Shaper (P < .05), and there were no significant differences for the other comparisons (P > .05). Analysis of the full canal length showed no statistically significant differences between the 3 tested systems (P > .05). Likewise, the tested systems did not differ significantly in cleaning the unprepared walls (P > .05). ConclusionsThere was no significant difference in the amount of unprepared surface areas between the 3 instrument systems, except for the comparison between the SAF and XP-endo Shaper in the apical 4-mm segment. None of them prepared 100% of the root canal walls. The cleaning ability of the 3 systems was similar.

A micro-computed tomographic study of band-shaped root canal isthmuses, having their floor in the apical third of mesial roots of mandibular first molars.

To conduct a quantitative and qualitative analysis of the band-shaped isthmus area, the floor of which was in the apical third in the mesial roots of mandibular first molars using micro-computed tomography (micro-CT). Micro-CT images of 269 mesial roots of mandibular first molars were evaluated, and 40 specimens with a band-shaped isthmus, with a floor in the apical third, were selected. The major diameter, minor diameter, roundness, area and perimeter values for the most coronal and apical slices where the isthmus was visible were measured. The distances between these slices were measured as the isthmus length, and the total volume, structure model index and surface area of the isthmus were measured. The distances between the isthmus floor and two apical foramina and the number of root canal orifices were calculated. The dimensions of the isthmus roof and the floor were compared, and the data were analysed using descriptive statistics and Student's t-tests with a significance threshold set at 5%. A total of 15% of the specimens had band-shaped isthmuses with a floor in the apical third. The isthmus roof exhibited significantly greater major and minor diameter values compared to the isthmus floor (P<0.05). No significant difference was detected between the isthmus roof and the floor with regard to roundness (P>0.05). Three- and two-dimensional analyses of the mesial roots of mandibular molars revealed that band-shaped isthmuses had complex shapes.

Influência do método de inserção do cimento resinoso na resistência adesiva de pinos de fibra de vidro.

Objetivos: Avaliar in vitro a influência do método utilizado para inserção do cimento resinoso RelyX U200 (3M ESPE) na resistência adesiva de pinos de fibra de vidro cimentados em pré-molares humanos.Métodos: 30 pré-molares extraídos foram selecionados, seccionados em 14 mm, submetidos a tratamento endodôntico (sistema ProTaper Universal - Dentsply Maillefer + obturação pela técnica de cone único com cimento AH Plus - Dentsply Maillefer) e, posteriormente, preparados para cimentação de pinos de fibra (manutenção de 4 mm apicais de material obturador). Então, os dentes foram aleatorizados de acordo com o método de inserção do cimento utilizado (n=10) (CENTRIX, PINO/CIMENTO, LENTULO) e pinos de fibra de vidro previamente silanizados foram então cimentados. Posteriormente, 3 slices por espécime (slice cervical, médio, apical) foram obtidos e submetidos ao teste de push-out na máquina de ensaio universal.Resultados: O método de inserção do cimento influenciou significativamente a resistência de união cimento-dentina (p=0,002), sendo que a CENTRIX (10,05 ± 3,25 Mpa) e LENTULO (9,80 ± 3,21 Mpa) apresentaram os melhores resultados. Adicionalmente, observou-se que a região proveniente do slice também influenciou (maiores valores de resistência de união para o terço cervical - 10,62 ± 3,66 Mpa).Conclusões: O uso de Centrix (Centrix Inc.) e Lentulo (Injecta Produtos Odontológicos) promovem um melhor resultado de resistência adesiva, em comparação ao cimento aplicado diretamente sobre o pino. Regiões mais apicais apresentam menor resistência adesiva do que cervicais.

Effect of ultrasonic and sonic activation of root canal sealers on the push-out bond strength and interfacial adaptation to root canal dentine.

To evaluate the effect of ultrasonic and sonic activation of two root canal sealers on interfacial adaptation and push-out bond strength (BS) to root canal dentine. The root canals of seventy-eight roots of maxillary canines were prepared with NiTi rotary instruments under irrigation with 2.5% NaOCl and 17% EDTA. Canals were filled by lateral condensation of gutta-percha and AH Plus (n=39) or MTA Fillapex (n=39). Three subgroups (n=13) were formed according to sealer activation: no activation (NA), sonic activation (SA, 20s) and ultrasonic activation (US, 20s). In three specimens of each subgroup, 0.1% rhodamine B was added to the sealer. Three 1-mm-thick slices were obtained from each root third. The first and second were used for push-out BS test and the third for a qualitative analysis of interfacial adaptation (gaps) and voids by confocal laser scanning microscopy (CLSM). Intratubular penetration of rhodamine B-labelled sealer was also assessed by CLSM. Data were analysed by two-way anova and Tukey's test (α=0.05). AH Plus (2.58±1.21) had higher push-out BS than MTA Fillapex (1.45±0.71) (P= 0.000). UA (2.64±1.44) had higher BS (P=0.000) than NA (1.58±0.73) and SA (1.83±0.85), which did not differ significantly from each other (P= 0.3303). The coronal third had higher BS (2.48± 1.49) than the middle (2.08±0.94) (P=0.0003) and apical (1.48±0.58) (P=0.00) thirds. For both sealers, UA was associated with a more homogeneous filling material with better interfacial adaptation and greater quantity, density and length of tags in dentinal tubules. When UA was used, the tags had similar quantity, density and length to those formed without activation, but interfacial gaps and voids were observed. Ultrasonic activation was associated with higher BS values, deeper intratubular penetration and greater interfacial adaptation to root dentine than sonic activation and no activation techniques, AH Plus had higher BS values than MTA Fillapex irrespective of the type of activation.

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.

Preexisting Dentinal Microcracks in Nonendodontically Treated Teeth: An Ex Vivo Micro–computed Tomographic Analysis

IntroductionThis study evaluated the prevalence, location, and pattern of preexisting dentinal microcracks in roots of extracted teeth without endodontic treatment in patients from 2 age groups using micro–computed tomographic imaging. MethodsSix hundred thirty-three nonendodontically treated teeth extracted using an atraumatic procedure because of reasons unrelated to this study were collected and divided based on the patient age. Teeth were scanned with micro–computed tomographic imaging (resolution of 26.7 μm) to examine the presence of preexisting dentinal microcracks in roots. The characteristic features of preexisting dentinal microcracks determined were location, extent, length, and coronoapical distribution. Chi-square bivariate analysis was performed to assess the association between various parameters. ResultsForty-five of 633 nonendodontically treated teeth exhibited preexisting microcracks in roots with a prevalence of 7.1%. The prevalence of preexisting microcracks was found to be 8.3% in older patients (40–70 years) compared with 3.7% in younger patients (20–39 years) (P < .050). A significant association was found between the preexisting microcracks in mandibular teeth (10.3%) when compared with maxillary teeth (2.9%) (P < .001). All preexisting microcracks were located mesiodistally; 66% occurred in the cervical and middle thirds of root. Only 33% of the preexisting microcracks were complete in nature, showing canal involvement. Complete dentinal microcracks exhibited a mean length of 6.9 mm, whereas incomplete cracks had a mean length of 3.75 mm (P < .001). ConclusionsPreexisting dentinal microcracks in roots of nonendodontically treated teeth occurred more often in older patients (40–70 years) in the mesiodistal direction. They were predominantly found in the cervical and middle thirds of root and were more likely to be incomplete in nature.

Long-term bond strength of a self-adhesive resin cement to intraradicular dentin pretreated with chlorhexidine and ethanol

Abstract Introduction Self-adhesive resin cements do not require prior preparation of the tooth surface, therefore dentin pretreatments may influence long-term bond strength. Objective To evaluate the influence of 100% ethanol (ET) and 2% chlorhexidine (CL) treatment of intraradicular dentin on the long-term bond strength (BS) of a self-adhesive resin cement (SRC). Material and method 80 bovine roots were restored with fiber posts and SRC (U200 3M/ESPE) and distributed into 4 groups according to dentin treatment: Group 1 – without treatment; Group 2 – 2% CL for 1 minute; Group 3 – 100% ET for 1 minute; Group 4 – 2% CL, followed by 100% ET. The samples were cross-sectioned to obtain two sections (0.7 mm) thick for each root third: coronal, middle and apical. The immediate push-out test was carried out after 48 hours, and the long-term push-out test, after 180 days. Result The three-way ANOVA test for randomized blocks showed no difference between the BS values at 48 hours and 80 days, irrespective of the treatment and the third (p&gt;0.05). The interaction of the treatment/third pairing was significant (p = 0.041) since the treatment with CL promoted lower BS in the coronal third, while treatment with ET promoted better BS in the apical third. Conclusion Treatment with CL and ET, separately or combined, promoted no differences between the BS values of the SRC to root dentin over time.

Evaluation of Intra Root Canal Er,Cr:YSGG Laser Irradiation on Prosthetic Post Adherence.

In clinical prosthetics procedures, including endodontics and post fixation, the presence of a smear layer can reduce the post bond strength. An Er,Cr:YSGG laser, which emits at 2780 nm, can promote a smear-layer-free surface due to the ablation process. Considering these aspects, the purpose of this work was to evaluate the influence of Er,Cr:YSGG laser irradiation using either a radial or an axial fiber tip on the bond strength of three resin cements to the fiber-reinforced composite posts. Ninety recently extracted single rooted human teeth had their root canal instrumented and were randomly distributed into nine experimental groups, in which three resin cements (total-etching Variolink II, self-etching Panavia F, and self-adhesive RelyX Unicem Aplicap) and three root canal treatments (no treatment, laser irradiation using the radial fiber tip, laser irradiation using the axial fiber tip) were used. Specimens were then sectioned into three sections (cervical, middle, and apical thirds) with two slices on each section. A push-out test was performed on each slice, and the values were recorded as MPa. The push-out data were analyzed by a Ryan-Joiner normality test followed by a two-way ANOVA test and Tukey pairwise comparison. The statistical analysis was performed on each third section separately, with a 5% significance level. Laser irradiation with axial fiber tip significantly increased the post bond strength of RelyX Unicem Aplicap on middle third of specimens (p<0.001) when compared to other root canal treatments (unlased or irradiated with radial tip). Considering the Panavia resin cement, laser irradiation with either axial or radial tips promoted a significant increase on the post bond strength of middle third when compared to unlased specimens (p < 0.001); however, laser irradiation did not influence the post bond strength of Variolink resin cement. The use of the Er,Cr:YSGG laser for clinical prosthetics procedures enhances the post bond strength of Panavia and RelyX Unicem Aplicap resin cements, mainly at middle third of roots, and does not interfere with the bond strength of Variolink resin cement. For the RelyX Unicem Aplicap system, the use of axial tip is most advantageous and can be recommended for future clinical application.

Effectiveness of the ProTaper Next and Reciproc Systems in Removing Root Canal Filling Material with Sonic or Ultrasonic Irrigation: A Micro–computed Tomographic Study

IntroductionThe aim of this study was to evaluate the effectiveness of ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland) and Reciproc (VDW, Munich, Germany) systems in removing filling material from oval root canals using sonic or ultrasonic irrigation as additional cleaning methods. MethodsThirty-two human extracted mandibular premolars with oval canals were prepared using the ProTaper Universal system (Dentsply Maillefer) up to instrument F4 (40/.06) and then filled by the single-cone technique using Endofill sealer (Dentsply Maillefer). The teeth were randomly divided into 4 groups (n = 8) according to the instrumentation system and the additional cleaning method as follows: Reciproc 40 with ultrasonic activation, Reciproc 40 with sonic agitation, ProTaper Next (X2, X3, and X4) with ultrasonic activation, and ProTaper Next (X2, X3, and X4) with sonic agitation. All specimens were analyzed using micro–computed tomographic imaging before and after removal of the filling material and also after applying the additional cleaning methods. The data, in mm3 of remaining filling material, were analyzed by the Kruskal-Wallis, Dunn, and Mann-Whitney tests. ResultsNone of the retreatment protocols completely removed the filling material from the root canals, and there was no significant difference between the instrumentation systems or between root thirds assessed in terms of the average volume of remaining filling material (P > .05). Likewise, no significant difference was observed between the additional cleaning methods in any of the root canal thirds assessed (P > .05). ConclusionsThe ProTaper Next and Reciproc systems were equivalent with respect to effectiveness in removing filling material regardless of the additional cleaning method used. The additional cleaning methods were also equivalent and did not improve the removal of filling material significantly.

Effect of Blood Contamination on Push-Out Bond Strength of Mineral Trioxide Aggregate Mixed with Different Liquids

Mineral trioxide aggregate (MTA) as a retrograde filling is always in contact with blood in the periradicular area during apical surgery. The purpose of this study was to investigate the effect of blood contamination on the push-out bond strength of MTA mixed with sterile water, local anesthetic, and 5% CaCl2. Thirty middle thirds of mandibular premolar roots were randomly assigned into three groups of ten. Group 1: MTA mixed with sterile water. Group 2: MTA mixed with local anesthetic (2% lidocaine HCl). Group 3: MTA mixed with 5% CaCl2. Each group was then divided into two groups: group A, in which specimens were contaminated by blood, and group B, in which specimens were not contaminated by blood. Specimens were stored in an incubator with a temperature of 37 °C for 72 h, subjected to a push-out test, and observed under a stereo-microscope at a magnification of 40× to determine the nature of the bond failure between MTA and dentinal walls. The data were analyzed using two-way analysis of variance and Tukey’s post hoc test with a 5% significance level. The results show that blood contamination reduced the push-out bond strength of MTA mixed with either sterile water, local anesthetic, or 5% CaCl2 (P < 0.05). The predominant failure in each group was a mixture of adhesive and cohesive types. MTA mixed with local anesthetic produced the lowest push-out bond strength, and MTA mixed with 5% CaCl2 had the greatest push-out bond strength.

Effect of Anatomical Customization of the Fiber Post on the Bond Strength of a Self-Adhesive Resin Cement

Aim The aim of the study was to evaluate, by means of the push-out test, the effect of the anatomical customization of the fiber post on the bond strength of a self-adhesive resin cement. Methods Twelve endodontically treated, human, upper central incisors were randomly divided into two groups (n = 6): control (glass fiber posts cemented with Relyx® U200) and customized (glass fiber posts anatomically customized with translucent composite resin cemented with Relyx U200). The roots were sectioned into three slices, cervical, middle, and apical, and photographed with a digital camera attached to a stereomicroscopic loupe. The images were analyzed by software, for evaluation of the cement line. The slices were subsequently submitted to the push-out test until the post had completely extruded, and the fracture mode was analyzed with a stereomicroscopic loupe. Results The results showed significant differences between the groups in the different root thirds in relation to the area occupied by air bubbles (p < 0.05). Bond strength, when all the thirds are considered, was 8.77 ± 4.89 MPa for the control group and 16.96 ± 4.85 MPa for the customized group. Conclusion The customized group showed greater bond resistance than the control group and a more uniform cement layer.

The use of auxiliary devices during irrigation to increase the cleaning ability of a chelating agent.

ObjectivesThis study investigated the cleaning ability of ultrasonically activated irrigation (UAI) and a novel activation system with reciprocating motion (EC, EasyClean, Easy Equipamentos Odontológicos) when used with a relatively new chelating agent (QMix, Dentsply). In addition, the effect of QMix solution when used for a shorter (1 minute) and a longer application time (3 minutes) was investigated.Materials and MethodsFifty permanent human teeth were prepared with K3 rotary system and 6% sodium hypochlorite. Samples were randomly assigned to five groups (n = 10) according to the final irrigation protocol: G1, negative control (distilled water); G2, positive control (QMix 1 minute); G3, QMix 1 minute/UAI; G4, QMix 1 minute/EC; G5, QMix 3 minutes. Subsequently the teeth were prepared and three photomicrographs were obtained in each root third of root walls, by scanning electron microscopy. Two blinded and pre-calibrated examiners evaluated the images using a four-category scoring system. Data were statistically analyzed using Kruskal-Wallis and Dunn tests (p < 0.05).ResultsThere were differences among groups (p < 0.05). UAI showed better cleaning ability than EC (p < 0.05). There were improvements when QMix was used with auxiliary devices in comparison with conventional irrigation (p < 0.05). Conventional irrigation for 3 minutes presented significantly better results than its use for 1 minute (p < 0.05).ConclusionsQMix should be used for 1 minute when it is used with UAI, since this final irrigation protocol showed the best performance and also allowed clinical optimization of this procedure.

Effect of Different Surface Treatments on Cone Beam Computed Tomography Image and Push Out Bond Strength of Conventional and Reinforced Fiber Posts.

Statement of problem: Surface treatment of reinforced fiber posts may not always increase adhesion, especially on post/resin based luting agent interface which is weaker than the dentin/adhesive interface. Relatively little information is available on cone beam computed tomography as non-destructive method suitable for investigating the details of the tooth structure and restoration relationship. Purpose: The purpose of this study was performed to evaluate porosities and gaps at post/ root dentin interface by CBCT and correlate them to push out bond strength of conventional and reinforcedglass fiber posts after different surface treatments; hydrofluoric acid, hydrogen peroxide and sandblasting. Materials and Methods: Forty human maxillary central incisors were selected, decoronated to set the remaining tooth length to standardized length of 13mm from the root apex and endodontically treated. The prepared roots were randomlydivided into 2 fiber post groups(20 per each). Group 1: white posts DC were selected. Group 2: easy-postsTM were selected. Within each group, posts were further subdivided into 4 subgroups (5 per each) according to surface treatments of the posts. Subgroup A: no treatment, the posts acting as control group. Subgroup B: etching by 9% buffered hydrofluoric acid for 1 minute and bonding. Subgroup C: immersion in 20% H2O2 for 15 minutes and double application of silane for 1 minute per each application. Subgroup D: sandblasting by alumina particles and silainization for 1 minute.Posts were cemented inside roots using Duo-link UniversalTM resin cement. Samples were examined by CBCT scans to evaluate voids and porosities. The CBCT scans of intra canal posts were measured in the axial plane. All measurements were made at cervical and middle slices in the buccal, lingual, mesial & distal directions. Each specimen was transversely sectioned perpendicular to the long axis of the root to obtain a section 2 mm ± 0.1 in thickness from the root thirds as measured using a digital caliper. Each section was coded and photographed from apical and coronal surfacesusing a stereomicroscope.. Three-way analysis of variance ANOVA test of significance was done comparing variables (post, surface treatment and radicular region) affecting mean values. One way ANOVA followed by Tukey’s post-hoc test was performed

Long-term bond strength of fiber posts cement to dentin with self-adhesive or conventional resin cements

The aim of this study was to evaluate the immediate and the long-term push-out bond strength of glass fiber posts (GFP) cemented with conventional or self-adhesive dual-curing resin cements, at different root depths. Prior to cementation, the GFP (Reforpost #3, Angelus) were etched with 37% phosphoric acid for 30 s followed by silane for 1 min. Thirty canine roots were divided into two groups (n = 15) according to resin cement type: ARC – dual resin cement (RelyX ARC/3M ESPE) combined with an three-step etch-and-rinse adhesive (Adper Scotch Bond Multi-Purpose Plus 3M/ESPE) or U200 – self-adhesive resin cement (RelyX U200/3M ESPE). The manufacturer’s instructions were followed. After 48 h, the roots were cross-sectioned at three different depths, resulting in serial slices corresponding to the cervical, middle, and apical root thirds. Slices were randomly divided into two groups, according to the period of water storage prior to push-out bond strength analysis: 48 h or 180 days. The data (MPa) were analyzed using three-way ANOVA for randomized blocks (p < 0.05), which showed no significant interaction between the three factors (p = 0.716). The main study factors were also proven not significant (cement: p = 0.711; time: 0.288; root third: p = 0.646). In conclusion, root depth, cement type (self-adhesive or conventional), and storage in water for 180 days did not influence the bond strength of GFP to intracanal dentin.

Evaluation of Different Passive Ultrasonic Irrigation Protocols on the Removal of Dentinal Debris from Artificial Grooves.

The aim of this study was to evaluate the influence of different passive ultrasonic irrigation protocols on the removal of debris in artificially created grooves in the cervical, middle and apical root thirds. Forty extracted bovine incisor roots were instrumented to 1 mm of the root apex with a R50 Reciproc instrument and irrigated with 2.5% sodium hypochlorite. The roots were then inserted in a muffle and cleaved into two hemisections. Grooves (3-mm long) were done at 2, 7 and 12 mm from the root apex in one hemisection and filled with dentinal debris. The hemisections were regrouped into the muffle and divided into 4 groups (n=10) according to the final irrigation protocol: Control group: 3x20 s using a #30 gauge needle without agitation of the irrigating solution; Group PUI-s (static passive ultrasonic irrigation): 3x20 s of passive ultrasonic irrigation with the tip of the insert maintained static on the apical third; Group PUI-t (passive ultrasonic irrigation per third): 20 s of PUI in each third; Group PUI-d (passive dynamic ultrasonic irrigation): 3x20 s of PUI dynamically moving the insert in the whole extent of the root canal. In all groups, was used a total of 6 mL of 2.5% sodium hypochlorite as irrigant. After these procedures, the grooves were analyzed with a stereomicroscope and assigned scores as regards removal of the debris. The data were analyzed statistically (a=0.05). The results showed a better cleaning in all the groups where the irrigating solution was agitated with ultrasonic device than in the control group (p<0.05). In the apical third, the PUI-d and PUI-s showed similar performance (p>0.05) and a better cleanness than PUI-t (p<0.05). The dynamic and static methods of agitation of the irrigating solution provided more effective cleaning. PUI-d provided the most completely clean grooves suggesting that its use is the most adequate in cases of teeth with complex canal anatomy.