Micro-CT Assessment of Filling Removal Effectiveness in the Apical Third of Curved Canals with Different Types of Anatomy.

Introduction: The aim of this study was to assess the effectiveness of filling removal material from the apical third of curved mesial root canals of mandibular molars. Reciprocating instrumentation followed by additional rotary instrumentation with instruments made of alloys with different heat treatments was evaluated. Materials and Methods: Thirty-six mesial roots of mandibular molars were divided into two groups: Group Class IV consisted of 16 roots with two independent canals, and Group Class II consisted of 20 roots with two canals that merged into one at their apical level. Each of these two groups were further divided into two subgroups, according to the additional rotary instrument used after the reciprocating instrumentation: Group RH and Group RM for Hyflex and Mtwo, respectively. After each procedural step, the roots were scanned by micro-tomography. After each step of filling removal, the Wilcoxon matched pair test and the Mann-Whitney test were used for the evaluation between groups. The significance level adopted was 5%. Results: Significant differences were observed between groups with different Class II and Class IV anatomies, regarding filling removal after Reciproc (P<0.05). After the use of an additional rotary instrumentation, no differences were observed between the two groups (P>0.05). Conclusions: In the apical third of mesial roots of mandibular molars with Class II anatomy, an additional rotary instrumentation was shown to be necessary for improving the removal of filling material after using the single-file reciprocating instrumentation technique.

Effect of ELVAX polymer subgingival implants with echistatin on extracted and reimplanted rats' teeth.

To investigate the effect of ELVAX polymer subgingival implants incorporated with echistatin peptide on incisor reimplanted tooth in rats. Forty-two male Wistars rats were divided into two groups: echistatin-treated rats (E) and control rats (C). The animals had their right maxillary incisors extracted and treated according to the International Association of Dental Traumatology replantation protocol. The extra-alveolar dry period was 30 and 60 min, and the post-surgical experimental periods were 15, 60, and 90 days. The samples were stained with H&E and analyzed for the presence of an inflammatory response, incidence of resorptions, and dental ankylosis. Results were statistically analyzed (p < 0.05). The presence of inflammatory resorption was significantly higher in group C at 30 and 60 min extra-alveolar time, in the 15-day postoperative period as compared with the E group (p < 0.05). Dental ankylosis was significantly more prevalent in group E in 30 min extra-alveolar time and 15 days postoperative period (p < 0.05). However, in 60 min extra-alveolar time and 60 days postoperative period, dental ankylosis was more prevalent in C group (p < 0.05). The use of ELVAX subgingival implants with echistatin demonstrated therapeutic potential in preventing the experimental resorption process after replantation of maxillary incisors in rats.

A new model of in vitro dentin intratubular contamination for Fusobacterium nucleatum: Validation by confocal laser scanning microscopy.

Objectives: To test and validate a new protocol for in vitro contamination of dentinal tubules using Fusobacterium nucleatum (F. nucleatum) by confocal laser scanning microscopy (CLSM), in addition to evaluating the effectiveness of conventional endodontic irrigants such as sodium hypochlorite (NaOCl) and chlorhexidine (CLX) on this biofilm. Material and methods: Thirty lower premolars were contaminated with F. nucleatum (ATCC 51190) for 7 days under anaerobic conditions using the proposed new model. The specimens were divided into a control group and experimental groups, according to the irrigants: NaOCl 2.5% and CLX 2%. Then, the samples were submitted for analysis by CLSM and the LIVE/DEAD technique to quantify bacterial viability. Data normality was verified by the Shapiro-Wilk test. Intragroup and intergroup comparisons were performed using the Kruskal-Wallis test, followed by Dunn's post-test. Results: The CLSM images obtained demonstrated the effectiveness of the proposed new contamination protocol, with a high percentage of viable bacteria in relation to the treated groups (p < 0.05). Lower viability values were observed for the 2.5% NaOCl group. Conclusion: The new contamination protocol resulted in a high and homogeneous percentage of viable bacteria in the dentinal tubules in all specimens evaluated. Both irrigating solutions proved to be effective in reducing the intratubular microbiota, especially 2.5% NaOCl.

Final irrigation protocols can be used to promote stable long-term bond strength of AH Plus to dentin.

Irrigation solutions might affect dentin surface characteristics and, consequently, endodontic sealers adhesion. This study analyzed the effect of different final irrigation protocols on push-out bond strength (BS) of AH Plus to dentin seven days and 20 months after obturation. Scanning electron micrographs were obtained from the dentin surface of one sample/group after final irrigation. Canals of bovine incisors were instrumented and received final irrigation with (n=21): G1 - 2.5% sodium hypochlorite (NaOCl) + distilled water; G2 - 2.5% NaOCl + 17% EDTA; G3 - 2.5% NaOCl + 17% EDTA + 2.5% NaOCl; G4 - 2.5% NaOCl + 17% EDTA + 2% chlorhexidine (CHX); G5 - mixture 5% NaOCl + 18% etidronate (HEDP); and G6 - mixture 5% NaOCl + 10% tetrasodium EDTA (Na4EDTA). After irrigation, one root/group was split and images were obtained by scanning electron microscopy (SEM). The other 20 roots/group were filled with only AH Plus sealer. Three slices/root were used for push-out assessment seven days and 20 months after obturation. One-way analysis of variance and Tukey (α<0.05) were used to compare the results among experimental groups, and unpaired t-test (α<0.05) was used to compare the results of the same group over time. The photomicrographs showed that, excepting G1, all groups completely removed the smear layer from the samples. In G2 and G4, the opening of the dentin tubules enlarged. In G3, erosion was observed in the peritubular and intertubular dentin. Values of the BS in the seven days were G2=G3=G4=G5>G6=G1 and in the 20 months were G3=G5>G6=G4>G1=G2. G3, G5, and G6 presented values of BS in 20 months similar to the values of seven days (P>0.05). The final irrigation protocols tested produced dentin surfaces with different characteristics. Only G3 and G5 presented high BS values that were stable over time.

Postoperative Pain After Using Passive Ultrasonic Irrigation and EasyClean Device, Irrigation Activation Techniques: A Randomized Clinical Trial.

INTRODUCTION: This randomized clinical trial aimed to compare postoperative pain after the use of 2different irrigation activation techniques: passive ultrasonic irrigation and the EasyClean device. METHODS: Sixty-six single-rooted teeth diagnosed with asymptomatic pulp necrosis and apical periodontitis were randomly assigned to 2experimental groups (n = 33), which differed in the irrigation activation technique. Postoperative pain levels were assessed after 24, 48, and 72 hours using a verbal rating scale; the ibuprofen intake amount was recorded at the same time intervals. Data were analyzed using Student's t-test, Mann-Whitney U and Fisher's exact tests, with a significance level of 5%. RESULTS: Postoperative pain levels and analgesic intake frequency were not significantly different across the 2irrigation activation techniques (P > .05). The frequencies obtained in relation to the prevalence of postoperative pain were 3.1-25.8% for all participants of the 2studied groups. CONCLUSION: The irrigation activation techniques of passive ultrasonic irrigation and the EasyClean device were found to be equivalent in terms of postoperative pain and analgesic intake.

Influence of temperature on the torsional properties of two thermally treated NiTi rotary instruments.

This study aimed to evaluate the influence of temperature on torsional strength and angular deflection of two experimental NiTi rotary instruments manufactured from Blue and Gold thermal treatments and with identical cross-sections. A total of 40 experimental NiTi instruments 25.06 and with a triangular cross-section and manufactured from Blue and Gold thermal treatments were used (n=20). The torsional test was performed in the 3 mm from the tip of the instrument according to ISO 3630-1. The torsional test evaluated the torsional strength and angular deflection to failure at room temperature (21°C ± 1° C) and body temperature (36°C ±1°C). The fractured surface of each fragment was observed by using scanning electron microscopy (SEM). Data were analyzed using an unpaired t test for inter and intra-group comparison and the level of significance was set at 5%. The results showed that the body temperature did not affect the torsional strength and angular deflection of the instruments when compared with room temperature (P>0.05). However, at body temperature, the Blue NiTi instruments presented significantly lower angular deflection in comparison with Gold NiTi instruments (P<0.05). There was no significant difference regarding the torsional strength of the instruments at body temperature (P>0.05). The temperature did not affect the torsional strength of the instruments manufactured from Blue and Gold technology. However, the Blue NiTi instruments presented significantly lower angular deflection than Gold instruments at 36°C temperature.

Influence of temperature on the torsional properties of two thermally treated NiTi rotary instruments

Abstract This study aimed to evaluate the influence of temperature on torsional strength and angular deflection of two experimental NiTi rotary instruments manufactured from Blue and Gold thermal treatments and with identical cross-sections. A total of 40 experimental NiTi instruments 25.06 and with a triangular cross-section and manufactured from Blue and Gold thermal treatments were used (n=20). The torsional test was performed in the 3 mm from the tip of the instrument according to ISO 3630-1. The torsional test evaluated the torsional strength and angular deflection to failure at room temperature (21°C ± 1° C) and body temperature (36°C ±1°C). The fractured surface of each fragment was observed by using scanning electron microscopy (SEM). Data were analyzed using an unpaired t test for inter and intra-group comparison and the level of significance was set at 5%. The results showed that the body temperature did not affect the torsional strength and angular deflection of the instruments when compared with room temperature (P>0.05). However, at body temperature, the Blue NiTi instruments presented significantly lower angular deflection in comparison with Gold NiTi instruments (P<0.05). There was no significant difference regarding the torsional strength of the instruments at body temperature (P>0.05). The temperature did not affect the torsional strength of the instruments manufactured from Blue and Gold technology. However, the Blue NiTi instruments presented significantly lower angular deflection than Gold instruments at 36°C temperature.

Resumo O objetivo deste estudo foi avaliar a influência da temperatura nas propriedades de torção (resistência à torção e deflexão angular) de dois instrumentos rotatórios experimentais de NiTi fabricados com secção triangu.ar e tratamentos térmicos Blue e Gold. Quarenta instrumentos experimentais de NiTi 25.06 com tratamento térmico Blue e Gold foram usados (n= 20). Foi avaliada a resistência torcional e a deflexão angular até a fratura na temperatura ambiente (21°C ± 1°C) e corporal (36°C ± 1°C). O teste torcional foi realizado nos 3 mm da ponta dos instrumentos de acordo com a ISO 3630-1. A superfície fraturada de cada instrumento foi observada pelo microscópio eletrônico de varredura (MEV). Os dados foram analisados por meio do teste t não pareado para a comparação inter e intragrupos e o nível de significância à 5%. Os resultados demonstraram que a temperatura corporal não afetou a resistência a torção e deflexão angular quando comparada com a temperatura ambiente (P>0.05). No entanto, na temperatura de 36°C o instrumento com tratamento térmico Blue apresentou menor deflexão angular quando comparado com o Gold (P<0.05). Não houve diferença significante entre os dois instrumentos em relação a resistência à torção. A temperatura corporal não modificou a resistência torcional dos instrumentos fabricados com tecnologia Blue e Gold. No entanto, os instrumentos com NiTi Blue apresentaram menor deflexão angular do que o Gold a 36°C.

Final irrigation protocols can be used to promote stable long-term bond strength of AH Plus to dentin

Abstract Irrigation solutions might affect dentin surface characteristics and, consequently, endodontic sealers adhesion. Objective This study analyzed the effect of different final irrigation protocols on push-out bond strength (BS) of AH Plus to dentin seven days and 20 months after obturation. Scanning electron micrographs were obtained from the dentin surface of one sample/group after final irrigation. Methodology Canals of bovine incisors were instrumented and received final irrigation with (n=21): G1 - 2.5% sodium hypochlorite (NaOCl) + distilled water; G2 - 2.5% NaOCl + 17% EDTA; G3 - 2.5% NaOCl + 17% EDTA + 2.5% NaOCl; G4 - 2.5% NaOCl + 17% EDTA + 2% chlorhexidine (CHX); G5 - mixture 5% NaOCl + 18% etidronate (HEDP); and G6 - mixture 5% NaOCl + 10% tetrasodium EDTA (Na4EDTA). After irrigation, one root/group was split and images were obtained by scanning electron microscopy (SEM). The other 20 roots/group were filled with only AH Plus sealer. Three slices/root were used for push-out assessment seven days and 20 months after obturation. One-way analysis of variance and Tukey (α<0.05) were used to compare the results among experimental groups, and unpaired t-test (α<0.05) was used to compare the results of the same group over time. Results The photomicrographs showed that, excepting G1, all groups completely removed the smear layer from the samples. In G2 and G4, the opening of the dentin tubules enlarged. In G3, erosion was observed in the peritubular and intertubular dentin. Values of the BS in the seven days were G2=G3=G4=G5>G6=G1 and in the 20 months were G3=G5>G6=G4>G1=G2. G3, G5, and G6 presented values of BS in 20 months similar to the values of seven days (P>0.05). Conclusions The final irrigation protocols tested produced dentin surfaces with different characteristics. Only G3 and G5 presented high BS values that were stable over time.

Effect of obturation technique on penetration of calcium silicate-based sealer into dentinal tubules after endodontic retreatment of mandibular premolars.

OBJECTIVE: Confocal laser scanning microscopy (CLSM) was used to investigate the penetration of endodontic sealers into the dentinal tubules after retreatment using two different obturation techniques. MATERIALS AND METHODS: Thirty mandibular premolars were prepared up to instrument F3 (ProTaper Universal, Dentsply) and filled with Endofill using the single cone technique. The canals were retreated using Mtwo instruments. Reobturation was performed with the Bio-C sealer mixed with a fluorophore dye (Fluo-3) using either the lateral condensation technique (group LC) or the single cone technique (group SC) (n = 15). Teeth were sectioned 2, 4, and 6 mm from the apex and analyzed with CLSM to assess the penetration of the sealer into the canal perimeter and the maximum depth of penetration of the sealer into the dentinal tubules. Data were analyzed using ANOVA and the Student-t and Holm-Sidak tests. RESULTS: In the apical segment, the penetrated perimeter was significantly higher in the LC group than in the SC group (p < 0.05); no significant difference was found in the middle and cervical segments (p > 0.05). In terms of penetration depth, no significant differences were found for any of the segments studied (p > 0.05). CONCLUSION: The LC technique promoted a higher percentage of canal circumference penetrated by the sealer than the SC technique in the apical segment after endodontic retreatment. CLINICAL RELEVANCE: CLSM demonstrated that the LC technique promoted a higher percentage of canal perimeter penetrated by the Bio-C sealer than the SC technique in the apical segment of mandibular premolars after retreatment.

Effect of nickel-titanium alloys on root canal preparation and on mechanical properties of rotary instruments.

The aim of this study was to evaluate the quality of curved root canal preparation, torsional fatigue, and cyclic fatigue of rotary systems manufactured with different NiTi alloys. Ninety single-rooted canals with curvatures of 15° to 30o were scanned and divided into three groups according to the rotary system used: BT-Race (BTR) - 10.06, 35.00, 35.04; SequenceRotaryFile (SRF) - 15.04, 25.06, 35.04; and ProDesignLogic (PDL) - 25.01, 25.06, 35.05. Each system was used on three specimens. The teeth were prepared, scanned, and analyzed to assess increase in volume, transportation, and centering ability of the root canal. Torsional fatigue of glide path instruments (BTR 10.06, SRF 15.04 and PDL 25.01) and cyclic fatigue of the finishing instrument (BTR 35.04, SRF 35.04 and PDL 35.05) were obtained by analyzing completely new instruments (n = 10) and instruments after they had been used three times (n = 10). After the torsional and cyclic fatigue tests, the fractured surface of the new and used instruments were examined by scanning electron microscopy. Increase in volume, canal transportation, and centering ability showed no significant differences among the groups (p > 0.05). The torsional test showed that SRF 15.04 produced the highest torque values for both new and used instruments, followed by PDL 25.01 and BTR 10.06 (p < 0.05). PDL 25.01, both new and used, exhibited higher values of angular deflection followed by SRF 15.04 and BTR 10.06 (p < 0.05). As regards cyclic fatigue, use of PDL 35.05, both new and used, required a longer time and larger number of cycles than did SRF 35.04 and BTR 35.04 (p < 0.05). Clinical use affected the torsional fatigue of BTR; however, cyclic fatigue was not significantly affected (p < 0.05). All rotary systems were able to prepare the curved canals satisfactorily and were used safely on the three specimens. Relative to torsional fatigue, SRF 15.04 exhibited a higher torque, and PDL 25.01, higher angular deflection. BTR 10.06 was the most affected by clinical use. PDL 35.05 showed greater resistance to cyclic fatigue.

An unusual repair of perforating internal inflammatory root resorption; a case report of endodontic treatment

Internal inflammatory root resorption (IIRR) can occur as a serious complication of dental trauma which leads to progressive loss of the root structure. An early diagnosis could influence the therapeutic approach, but endodontic treatment becomes a challenge with a doubtful prognosis. The present report described an unusual clinical presentation of an IIRR with perforation resulting from a trauma four years previous. A 15-year-old female patient was presented to our service with pain in the maxillary incisor region. Intraoral radiography revealed a large radioloucent area compatible with IIRR, communicating with the periodontium in the middle third on the distal root face of the right central incisor. The root canal of the right central incisor was chemo-mechanically prepared. The calcium hydroxide (CH) intracanal medication was used and renewed periodically four times. The root canal was filled only in the cervical region to the level of resorption by the inverted gutta-percha cone technique. Clinically and radiographically, all follow-up examinations revealed an asymptomatic tooth, evidencing periapical tissue repair and new bone formation. The tooth remained asymptomatic 3 years afterwards. The present case report supports the idea of executing satisfactory intracanal decontamination by chemo-mechanical preparation, thus creating a favourable environment for tissue repair.

Evaluation of foramen locating accuracy of an endodontic motor integrated with electronic foramen employing optimal glide path kinematics.

OBJECTIVE: This study aimed to evaluate the accuracy of the auto apical function in the maintenance of the apical limit of instrumentation during glide path procedures when associated to OGP kinematics of Tri Auto ZX2, compared to the continuous rotation of the same motor, as well as Root ZX II and VDW Gold. MATERIALS AND METHODS: Forty-eight extracted human mandibular single-rooted premolars were selected. After endodontic access, cervical pre-flaring was performed using size 30, 0.10 taper rotary instruments, and the apical foramen size was standardized to 200 µm. Teeth were randomly divided into four groups (n = 12) according to the device and kinematics. For all the groups, the Auto Apical Stop function (AAS) was set to the 0.0 mark. Glide path instruments size 25, .01 taper were activated inside the canals until the apical limit was reached. Then, the files were fixed with cyanoacrylate to the teeth and decoupled from the equipment. Data were statistically analyzed in GraphPad Prism 6.0 software with the significance set at 5% (Kruskal-Wallis tests). RESULTS: There was no difference in the mean deviation between the groups. No significant difference was found among the groups when the distributions and percentages of differences between the file tip and the apical foramen were compared (P > 0.05). CONCLUSION: The use of auto apical function at the 0.0 mark of all tested devices provided an adequate control of the apical limit during glide path preparation. Foramen locating accuracy of Tri Auto ZX2 in OGP kinematics was similar to those of Tri Auto ZX2, Root ZX II, and VDW Gold in continuous kinematics. CLINICAL RELEVANCE: Clinical strategies in canal negotiation and glide path as OGP motion associated to electronic foramen locators could reduce iatrogenic risk of deviation and file fractures and create an easier initial preparation to facilitate endodontic procedures.

Effect of nickel-titanium alloys on root canal preparation and on mechanical properties of rotary instruments

Abstract The aim of this study was to evaluate the quality of curved root canal preparation, torsional fatigue, and cyclic fatigue of rotary systems manufactured with different NiTi alloys. Ninety single-rooted canals with curvatures of 15° to 30o were scanned and divided into three groups according to the rotary system used: BT-Race (BTR) - 10.06, 35.00, 35.04; SequenceRotaryFile (SRF) - 15.04, 25.06, 35.04; and ProDesignLogic (PDL) - 25.01, 25.06, 35.05. Each system was used on three specimens. The teeth were prepared, scanned, and analyzed to assess increase in volume, transportation, and centering ability of the root canal. Torsional fatigue of glide path instruments (BTR 10.06, SRF 15.04 and PDL 25.01) and cyclic fatigue of the finishing instrument (BTR 35.04, SRF 35.04 and PDL 35.05) were obtained by analyzing completely new instruments (n = 10) and instruments after they had been used three times (n = 10). After the torsional and cyclic fatigue tests, the fractured surface of the new and used instruments were examined by scanning electron microscopy. Increase in volume, canal transportation, and centering ability showed no significant differences among the groups (p > 0.05). The torsional test showed that SRF 15.04 produced the highest torque values for both new and used instruments, followed by PDL 25.01 and BTR 10.06 (p < 0.05). PDL 25.01, both new and used, exhibited higher values of angular deflection followed by SRF 15.04 and BTR 10.06 (p < 0.05). As regards cyclic fatigue, use of PDL 35.05, both new and used, required a longer time and larger number of cycles than did SRF 35.04 and BTR 35.04 (p < 0.05). Clinical use affected the torsional fatigue of BTR; however, cyclic fatigue was not significantly affected (p < 0.05). All rotary systems were able to prepare the curved canals satisfactorily and were used safely on the three specimens. Relative to torsional fatigue, SRF 15.04 exhibited a higher torque, and PDL 25.01, higher angular deflection. BTR 10.06 was the most affected by clinical use. PDL 35.05 showed greater resistance to cyclic fatigue.

Ultrasonic agitation reduces the time of calcium hydroxide antimicrobial effect and enhances its penetrability.

OBJECTIVES: The objective of the present work was to evaluate the ultrasonic agitation, time and vehicle (propylene glycol or distilled water) on the antimicrobial potential and penetrability of calcium hydroxide pastes on infected dentin by means of Confocal Laser Scanning Microscopy (CLSM) and microbiological culture (MC). MATERIALS AND METHODS: Dentin specimens were infected with Enterococcus faecalis using a new contamination protocol of 5 days. The specimens were divided into eight groups and dressed with the pastes for 7 or 15 days: G1) calcium hydroxide (CH) + propylene glycol (prop)/7 days (d), G2) CH + prop/7d + ultrasonic agitation (U), G3) CH + distilled water (dw)/7d, G4) CH + dw/7d + U, G5) CH + prop/15d, G6) CH + prop/15d + U, G7) CH + dw/15d, G8) CH + dw/15d + U. The ultrasonic activation was made for 1 min in both directions with a plain point insert. After medications removal, the images obtained by CLSM showed the viable (green) and dead (red) bacteria with Live and Dead dye. By the MC, the dentinal wall debris obtained by burs were collected for colony counts. For the penetration test, the Rodamine B dye was added to the CH pastes and analyzed by CLSM. RESULTS: The 7 and 15-days CH + prop+U pastes performed better antimicrobial efficacy, followed by the CH + dw+U/15d paste. CONCLUSIONS: All pastes demonstrated better penetration and antimicrobial activity against E. faecalis when agitated with ultrasound, even in periods of up to seven days. The propylene glycol vehicle showed better results. CLINICAL RELEVANCE: Agitation of the dressing that remains for less time inside the root canal can optimize the decontamination of endodontic treatment.

Procedimentos regenerativos endodônticos com clorexidina a 2% e hidróxido de cálcio: relato de caso / Endodontic regenerative procedures with 2% chlorhexidine and calcium hydroxide: case report

Introdução: Muitas substâncias têm sido utilizadas como irrigantes e curativos intracanal nos tratamentos de dentes com rizogênese incompleta, visando obter a regeneração pulpar. A clorexidina a 2% em associação com hidróxido de cálcio P.A. pode ser uma alternativa. Métodos: No presente caso clínico, o dente #45 com periodontite apical, em um paciente com 13 anos de idade, foi tratado com solução de clorexidina a 2% como irrigante. A clorexidina na forma de gel a 2% foi utilizada como auxiliar da instrumentação e, em associação com o hidróxido de cálcio, foi utilizada como curativo durante 14 dias. Após esse período, o canal foi irrigado com solução fisiológica e, sob anestesia alveolar mandibular, uma lima K #70 foi utilizada ultrapassando levemente o ápice, para causar sangramento. Após observar que o sangue dentro dos canais alcançou a porção cervical, o cimento biocerâmico MTA Branco foi colocado na porção cervical do canal. Resultados: A apicificação e o desenvolvimento da raiz em comprimento e largura puderam ser observados já no controle de três meses, e continuaram até a última revisão, no controle de um ano. Alterações de cor não foram observadas nese período de acompanhamento. Conclusões: A clorexidina associada ao hidróxido de cálcio pode ser uma alternativa aos procedimentos de regeneração pulpar (AU).

Introduction: Many substances have been used as irrigating solutions to promote pulp regeneration and root development in teeth with incomplete rhizogenesis. The use of 2% chlorhexidine as an irrigating solution in association with Calcium Hydroxide could be an alternative. Methods: In the case of the patient, a 13-year-old boy, here presented, tooth 45 with apical periodontitis was treated with 2% Chlorhexidine solution as irrigant adjuvant to instrumentation, in association with Calcium Hydroxide used as a dressing for 14 days. After this period, the canal was cleaned with a physiological solution and under mandibular alveolar anesthesia, a # 70 K file was used slightly over the apex to cause bleeding. After observing that blood inside the canals had reached the cervical portion. White MTA was placed in the cervical portion of the canal. Results: Induced apexification and development of increasing root length and width could already be observed in the three-month control exam, and this continued until the last review in the one-year control exam. No color changes were observed in this follow-up period. Conclusions: Chlorhexidine and calcium hydroxide could be used as an alternative to pulp regeneration procedures (AU).

Analysis of Instrumentation Protocols Regarding the Quality of Mesial Canal Preparation in Mandibular Molars: A Micro-computed Tomographic Study.

INTRODUCTION: This study aimed to use micro-computed tomographic imaging to analyze the quality of the endodontic preparation of mesial canals in mandibular molars provided by 3 instrumentation protocols. METHODS: Forty-five extracted mandibular molars with 2 independent mesial canals were selected, and the initial micro-computed tomographic imaging was performed. The initial volume values of the canals were submitted to statistical analysis for paired division. The groups were determined according to the final enlargement of the canal and the working length adopted (ie, G25.06/+1 mm, G35.05/foramen, and G50.01/-1 mm). At the end of each instrumentation sequence, the root canals were scanned and analyzed with regard to the increase in the total and apical volume, centralization, and preparation transportation and the percentage of the total and apical uninstrumented walls. RESULTS: For the intragroup comparison, the Wilcoxon test was used, and for the intergroup analysis, the Kruskal-Wallis and Dunn tests were used (P < .05). In the analysis of the canal total volume, a statistical difference was found between G25.06/+1 mm and the remaining groups (P < .05). In the apical third, a statistical difference was observed between G25.06/+1 mm and G50.01/-1 mm (P < .05). No statistical difference was found between the groups in terms of centralization and transportation of the preparation or in terms of the percentage of the total or apical uninstrumented walls. CONCLUSIONS: The preparation of the mesial canals of mandibular molars up to larger tip files but with a lower taper at 1 mm before the foramen resulted in a larger volume of apical preparation, kept the preparation centralized, and provided safe apical dentin wear without excessive cervical wear.

Orthodontic Movement of Central Incisor with Previously-healed Root Fracture associated with Unerupted Canines.

Teeth with root fracture may need orthodontic treatment. This case report presents the management of unerupted canines in a patient with previously-healed/untreated horizontal root fracture in the maxillary left central incisor. The malocclusion was treated maintaining pulp vitality considering the principles to improve the eruption path of maxillary canines and move short-rooted teeth. The root-fractured tooth remained symptomless after orthodontic treatment without significant adverse effects, and stayed stable following 2-year follow-up.

Tissue response to white mineral aggregate-based cement containing barium sulfate as alternative radiopacifier: A randomized controlled animal study.

The purpose of this study was to investigate the tissue reaction stimulated by BaSO4 - and Bi2 O3 -containing White MTA Angelus, in comparison with Bi2 O3 -containing white Portland cement, and white ProRoot MTA. Thirty-six adult male Wistar rats (Rattus norvegicus), weighing between 250 and 300 g, were distributed into three groups (n = 12) in accordance with the period of sacrifice (15, 30, and 60 days). Four polyethylene tubes filled with the tested cements were implanted into the dorsum of each rat. Lateral wall of the tubes served as the negative control. After the experimental periods, the animals were euthanized by overdose of pentobarbital anesthetic solution, and the specimens were prepared for microscopic analysis under ×50, ×100, and ×400 magnifications. Inflammatory scores (0-3) were used to grade the tissue reaction. Data were analyzed by the Kruskal-Wallis test and Dunn's test for individual comparisons (p < .05). A mild to moderate inflammatory tissue reaction was observed at the 15-day period, which decreased over the course of the periods for all cements, except for Portland cement. There was no significant difference among the tissue responses for ProRoot MTA, BaSO4 - and Bi2 O3 -containing White MTA Angelus at the 60-day period (p > .05). The Portland group had moderate inflammatory reaction at the final period of analysis, which was statistically different when compared to the other groups (p < .05). The microscopic findings of this animal study suggest that the addition of BaSO4 to White MTA Angelus does not hampers the biocompatibility of the cement.

Cyclic Fatigue Resistance of Nickel-Titanium Reciprocating Instruments after Simulated Clinical Use.

INTRODUCTION: The aim of this study was to evaluate the cyclic fatigue resistance of different heat-treated nickel-titanium reciprocating instruments in 2 different situations: new and used instruments after preparing 3 curved canals. METHODS: A total sample of 60 nickel-titanium instruments of 3 systems (n = 20 per system) were used in this study: ProDesign R (tip 25, 0.06 taper; Easy Dental Equipment, Belo Horizonte, Brazil), Reciproc Blue (tip 25, 0.08v taper; VDW, Munich, Germany), and WaveOne Gold (tip 25, 0.07v taper; Dentsply Sirona, Ballaigues, Switzerland). Thirty new instruments (n = 10 per system) were used to prepare 90 curved single-rooted mandibular premolars (n = 30). Each instrument was used to prepare 3 root canals, and after each canal preparation the instrument was ultrasonic cleaned and submitted to autoclave sterilization procedures. The other 30 instruments (n = 10 per system) were kept without use. Then, the new and used instruments were subjected to the cyclic fatigue test in an artificial canal with a 30° angle and a 5-mm radius of curvature. The time and number of cycles to fatigue were recorded. Data were analyzed using the unpaired t test for intragroup comparison. For intergroup comparison, analysis of variance and the Tukey test for multiple comparisons were used. RESULTS: The intergroup comparison of new instruments showed that ProDesign R had the highest cyclic fatigue resistance followed by Reciproc Blue and WaveOne Gold (P < .05). Regarding the used instruments, WaveOne Gold had the lowest cyclic fatigue resistance (P < .05). The intragroup comparison between new and used instruments showed that WaveOne Gold and ProDesign R presented a significant reduction in the cyclic fatigue resistance after simulated clinical use (P < .05); no difference was found with the Reciproc Blue instruments (P > .05). CONCLUSIONS: ProDesign R had the highest cyclic fatigue resistance, whereas WaveOne Gold had the lowest for new and used instruments. Simulated clinical use affected the cyclic fatigue resistance of ProDesign R and WaveOne Gold but not of Reciproc Blue instruments.

Comparação de diferentes métodos de inserção da pasta de hidróxido de cálcio para preenchimento de canais laterais simulados: estudo in vitro / Comparison of different methods for insertion of calcium hydroxide paste in the filling of simulated lateral canals: in vitro evaluation

Avaliar, em micro-CT, diferentes métodos de inserção da pasta de hidróxido de cálcio para preenchimento de canais laterais simulados em blocos de acrílico. Métodos: Foram utilizados 72 blocos de acrílico com canais laterais simuladas nas porções cervical, média e apical, os quais foram preenchidos com a pasta de hidróxido de cálcio de acordo com os seguintes métodos (n=12): Grupo 1 - lima tipo K #30; Grupo 2 - espiral de Lentulo; Grupo 3 - agitação ultrassônica; Grupo 4 - agitação sônica com EndoActivator; Grupo 5 - seringa + Capillari TIPS; e Grupo 6 - agitação com EasyClean em baixa rotação. Para os grupos que receberam agitação, o canal principal foi preenchido com a pasta utilizando seringa e Capillari Tips. Antes e após o preenchimento, os dentes foram escaneados em micro-CT (SkyScan 1174) e as imagens obtidas foram comparadas utilizando-se o software CTan. O volume de medicação intracanal no interior dos canais simulados foi mensurado e, em seguida, obtida a porcentagem de penetração. Os dados foram submetidos à comparação estatística (p<0,05). Resultados: Os grupos EndoActivator e ultrassom apresentaram resultados significativamente melhores do que a lima #30 nos três níveis analisados, assim como o EasyClean nos terços cervical e médio, e a Lentulo no terço apical, em relação ao Grupo 1 (p <0,05). Nas demais comparações e na análise intragrupos, não houve diferenças significativas (p>0,05). Conclusão: Os métodos de agitação da medicação intracanal, especialmente o ultrassom, proporcionaram uma maior porcentagem de penetração dela em canais laterais simulados (AU).

Objective: The objective of this study was to analyze, in micro-CT, the capacity of different methods for insertion of calcium hydroxide paste in the filling of lateral canals simulated in blocks of acrylic. Methods: A total of 72 acrylic blocks with lateral canals simulated in the coronal, middle and apical portions, were used and filled with calcium hydroxide paste, according to the following methods (n = 12): Group 1 - #30 K-file; Group 2 - Lentulo spiral; Group 3 - Ultrasonic agitation; Group 4 - Sonic agitation with EndoActivator; Group 5 - Syringe + Capillary Tips; Group 6 - Agitation with Easy Clean at low speed. For the groups that received agitation, the blocks were filled with the aid of a syringe and Capillary Tips. Each sample was scanned with SkyScan 1174, before and after the filling procedures, and the volume of calcium hydroxide was measured using CTAN software. The percentage of penetration of intracanal medication inside the simulated canals was calculated. Data were statistically compared (p < 0.05). Results: The agitation with EndoActivator and ultrasonic insert promoted a greater penetration of paste with significant statistical differences in relation to the #30 K-file group in the 3 levels analyzed (p < 0.05). Other statistical differences occurred in the comparison between the Easy Clean group and #30 K-file group in the coronal and middle thirds and in the comparison between Lentulo spiral group and #30 K-file group in the apical (p < 0.05). Conclusion: Methods which use agitation devices , such as ultrasonic insert, promoted higher filling of calcium hydroxide in simulated lateral canals (AU).