Influence of the type of vehicle and limit of obturation on apical and periapical tissue response in dogs' teeth after root canal filling with mineral trioxide aggregate

The purpose of this study was to investigate the influence of the type of vehicle (distilled water or propyleneglycol) on the response of apical tissues of dogs' teeth after root canal filling with mineral trioxide aggregate (MTA) at two different limits. Forty roots of incisors and premolars of two adult dogs were used. After pulpectomy, the root canals were prepared biomechanically, and the roots had the apical cemental barrier penetrated with a #15 K-file and widened to a #25 K-file. The root canals were assigned to four groups according to the vehicle used for MTA (ProRoot-MTA; Tulsa Dental, Tulsa, OK) preparation and the limit of root canal filling: group 1, filling with MTA/distilled water to the limit of the cemental canal; group 2, overfilling with MTA/distilled water, group 3, filling with MTA/propyleneglycol to the limit of the cemental canal; and group 4, overfilling with MTAlpropyleneglycol. The animals were killed by anesthetic overdose 90 days after endodontic treatment and the anatomic pieces were prepared for histomorphological analysis. The sections were stained with hematoxylin and eosin and Brown and Brenn techniques. The results showed that MTA pastes prepared with either distilled water or propyleneglycol as vehicles had similar biological behavior (p > 0.05); root fillings placed at the cemental canal limit showed better results than the overfillings (p = 0.01), and MTA/propyleneglycol paste was more easily placed into the root canals than MTA/distilled water paste.

Influence of apical patency and filling material on healing process of dogs' teeth with vital pulp after root canal therapy

Foi propósito deste trabalho observar o processo de reparo de dentes de cães após obturação dos canais com dois cimentos diferentes, fazendo ou não a patência apical. Após uma sobreinstrumentação, os canais receberam um curativo de uma solução de corticosteróide-antibiótico por 7 dias, com o objetivo de obter invaginação de tecido conjuntivo para dentro dos canais. Após esse período, esse tecido foi totalmente removido em metade dos casos (grupos com patência apical) e preservados no restante dos casos (grupos sem patência apical). Os canais foram obturados pela técnica da condensação lateral empregando um cimento a base de hidróxido de cálcio (Sealer Plus) ou um cimento de Grossman (Fill Canal). Os animais foram sacrificados por overdose anestésica 60 dias após o tratamento endodôntico e as peças anatômicas foram obtidas e preparadas para análise histológica. Os dados obtidos foram analisados com base em diversos parâmetros histomorfológicos. Os resultados foram melhores nos grupos sem patência apical (p=0,01) do que nos grupos com patência. Dentre os cimentos estudados, os melhores resultados foram observados com o cimento Sealer Plus (p=0,01). em conclusão, tanto a patência apical (presença ou ausência) quanto o tipo de material obturador de canal influíram no processo de reparo apical de dentes de cães com polpas vitais após tratamento endodôntico. O emprego de um cimento a base de hidróxido de cálcio em dentes sem patência apical promoveu os melhores resultados, dentre as condições experimentais propostas.

Tissue reaction to Endométhasone sealer in root canal fillings short of or beyond the apical foramen

Objective: This study evaluated the response of periapical tissues to the endodontic sealer Endomethasone in root canal fillings short of or beyond the apical foramen. Material and Methods: Twenty root canals of premolars and incisors of 2 mongrel dogs were used. After coronal access and pulp extirpation, the canals were instrumented up to a size 55 K-file and the apical cemental barrier was penetrated with a size 15 K-file to obtain a main apical foramen, which was widened to a size 25 K-file. The canals were irrigated with saline at each change of file. The root canals were obturated either short of or beyond the apical foramen by the lateral condensation of gutta-percha and Endomethasone, originating 2 experimental groups: G1: Endomethasone/short of the apical foramen; G2: Endomethasone/beyond the apical foramen. The animals were killed by anesthetic overdose 90 days after endodontic treatment. The individual roots were obtained and serial histological sections were prepared for histomorphological analysis (H&E and Brown & Brenn techniques) under light microscopy. The following parameters were examined: closure of the apical foramen of the main root canal and apical opening of accessory canals, apical cementum resorption, intensity of the inflammatory infiltrate, presence of giant cells and thickness and organization of the apical periodontal ligament. Each parameter was scored 1 to 4, 1 being the best result and 4 the worst. Data were analyzed statistically by the Wilcoxon nonparametric tests (p=0.05). Results: Comparing the 2 groups, the best result (p<0.05) was obtained with root canal filling with Endomethasone short of the apical foramen but a chronic inflammatory infiltrate was present in all specimens. Conclusions: Limiting the filling material to the root canal space apically is important to determine the best treatment outcome when Endomethasone is used as sealer.

Tissue reaction of the EndoREZ in root canal fillings short of or beyond an apical foramenlike communication

This study evaluated the response of periapical tissues to the endodontic sealer EndoREZ in root canal fillings short of or beyond the apical foramenlike communication. Twenty root canals of premolars and incisors of 2 mongrel dogs were used. After coronal access and pulp extirpation, the canals were instrumented up to a size 55 K-file and the apical cemental barrier was penetrated with a size 15 K-file to create an apical foramenlike communication, which was widened to a size 25 K-file. The canals were irrigated with saline at each change of file. The root canals were obturated either short of or beyond the apical foramenlike opening by the lateral condensation of gutta-percha and EndoREZ, originating 2 experimental groups: G1, EndoREZ/short of the apical foramenlike opening, and G2, EndoREZ/beyond the apical foramenlike opening. The animals were killed by anesthetic overdose 90 days after endodontic treatment. The individual roots were obtained and serial histological sections were prepared for histomorphological analysis (H&E and Brown and Brenn techniques) under light microscopy. The following parameters were examined: closure of the apical foramenlike communication and apical opening of accessory canals, apical cementum resorptions, intensity of the inflammatory infiltrate, presence of giant cells, and thickness and organization of the apical periodontal ligament. Each parameter was scored 1 to 4, 1 being the best result and 4 the worst. Data were analyzed statistically by the Wilcoxon nonparametric tests (P = .05). Comparing the 2 groups, the best result (P = .05) was obtained with root canal filling with EndoREZ short of the apical foramenlike opening. In conclusion, limiting the filling material to the root canal space apically was important to determine the best treatment outcome when EndoREZ was used as the sealer. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: e94-e99)

Comparison of the biocompatibility of different root canal irrigants

The purpose of this study was to compare the reaction of rat subcutaneous connective tissue to 0.9% sterile saline, 2.5% sodium hypochlorite (NaOCl), 5.25% NaOCl and 2% chlorhexidine gluconate solution or gel. Six circles were demarcated on the dorsal skin of 24 male Wistar rats, leaving 2 cm between each circle. Using a syringe, 0.1 mL of each root canal irrigant was injected subcutaneously into 5 circles. In the 6th circle, the needle of an empty syringe was introduced into the skin, but no irrigant was injected (control group). Evaluations were undertaken at 2 h, 48 h, 14 days and 30 days post-procedure. Tissue samples were excised, embedded in paraffin blocks and 3-mu m-thick sections were obtained and stained with hematoxylin and eosin. The areas of inflammatory reaction were evaluated and analyzed statistically by ANOVA and Tukey's test. The control group showed few or no inflammatory reaction areas in the subcutaneous tissue. 0.9% saline solution, 2.0% chlorhexidine solution and 2.5% NaOCl showed a good biocompatibility, as very mild inflammatory reaction was detected at 14 days and tissue repair occurred at 30 days. 5.25% NaOCl was the most toxic irrigant, as the number of inflammatory cells remained elevated at 14 and 30 days. The group treated with 2.0% chlorhexidine gluconate gel presented a moderate inflammatory response at 14 days, which decreased at 30 days, being considered similar to that of the control group, 0.9% saline solution, 2.0% chlorhexidine solution and 2.5% NaOCl at this experimental period.

Evaluation of the apical infiltration after root canal disruption and obturation

The aim of this study was to evaluate two root canal filling techniques used in teeth that had their apical foramen disrupted and compare the apical infiltration with an ideal clinical situation. Twenty-seven freshly extracted single-rooted teeth were selected and radiographed to confirm the existence of a single and straight root canal. The crowns were removed at a mean distance of 11 mm from the apex. The teeth had the root canals instrumented and were randomly assigned to 3 groups (n=9): ND group-root canals were filled using the lateral compaction technique and no disruption was performed; DRF group-the apical constriction was disrupted by advancing a #40 K-file 1 mm beyond the original working length, the canals were reinstrumented to create an apical ledge at 1 mm from the apical foramen and were obturated with a master gutta-percha cone with same size as the last file used for reinstrumentation; DF group - the teeth had the apical constriction disrupted and the canals were obturated with a master gutta-percha cone that fit at 1 mm from the apex. The teeth were submitted to dye leakage test with Rhodamine B for 7 days, using vaccum on the initial 5 min. The teeth were sectioned longitudinally and the leakage was measured in a linear fashion from apex to crown. There was no statistically significant difference (p>0.05) between the groups that had the apical foramen disrupted (DF, DRF), but significant difference was found between the disrupted groups and the non-disrupted one (p<0.01). In conclusion, none of the evaluated techniques was able to prevent apical infiltration, so working length so the working length determination has to be established and maintained carefully.

Detection of the Vandibular Canal and the Mental Foramen in Panoramic Radiographs: Intraexaminer Agreement

The aim of this study was to evaluate the intraexaminer agreement in the detection of the mandibular canal roof (MCR) and mental foramen (MF) in panoramic radiographs. Forty panoramic radiographs of edentulous patients were used. Two calibrated examiners (A and B) read the images 2 times, for both sides independently, under blind conditions. The interval between the readings was 10 days. The intraexaminer agreement in the interpretation of MCR and MF was performed by kappa statistics with linear weighting (x). The intraexaminer agreement for the detection of MCR, in the left side, was good for both examiners (A: kappa = 0.67; B: kappa = 0.71). Related to the right side, it was found to be kappa = 0.47 and kappa = 0.62, respectively to A and B. The intraexaminer agreement for the detection of MF was good for both examiners interpreting the left side (A: kappa = 0.61; B: kappa = 0.63), and in relation to the right side, it was moderate (A: kappa = 0.51) and fair (B: kappa = 0.38). The intraexaminer agreement in the detection of MCR was good and from good to fair in the detection of MF.

Incisive Canal Deflation for Correct Implant Placement: Case Report

Aim: This article is a case report of a patient in whom the prosthetic planning indicated the necessity of an incisive canal deflation for the correct installation of all implant that is to be osseointegrated.Case Report. In the reopening phase after the bone graft installation, the incisive canal deflation (biopsy of its content) was done and titanium implants were installed with one of them invading the anatomical space occupied previously by the incisive canal. The biopsy analysis showed fragments of the incisive artery and nerve., which are responsible for the anterior upper-tooth pulp, the periodontium vascularization. and the innervation. Front the anastomosis present along with other structures allied with the absence of teeth in the region, there was no detriment to the patient caused by the deflation.Conclusion: Incisive canal deflation is a viable technique in implantology. It can permit ideal prosthetic planning with no detriment to the patient. (Implant Dent 2009;18:473-479)

Antigenic Activity of Bacterial Endodontic Contents from Primary Root Canal Infection with Periapical Lesions against Macrophage in the Release of Interleukin-1 beta and Tumor Necrosis Factor alpha

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of the radiopacity of calcium hydroxide- and glass-ionomer-based root canal sealers

Aim To evaluate the radiopacity of calcium hydroxide-based root canal sealers (Acroseal, Sealapex and Sealer 26), a glass-ionomer-based sealer (Activ GP Sealer) and a zinc oxide and eugenol-based sealer (Intrafill).Methodology Five disc-shaped specimens (10 x 1 mm) were fabricated from each material, according to the International Organization for Standardization (ISO) 6876/2001 standard. After setting of the materials, radiographs were taken using occlusal films and a graduated aluminum step-wedge varying from 2 to 16 mm in thickness. The dental X-ray unit (GE1000) was set at 50 Kvp, 10 mA, 18 pulses s(-1) and distance of 33.5 cm. The radiographs were digitized and the radiopacity compared with that of the aluminum step-wedge, using WIXWIN-2000 software (Gendex). Data (mm Al) were submitted to ANOVA and Tukey test.Results Intrafill was the most radiopaque material (7.67 mm Al) followed by Sealer 26 (6.33 mm Al), Sealapex (6.05 mm Al) and Acroseal (4.03 mm Al). Activ GP was the least radiopaque material (1.95 mm Al, P < 0.05).Conclusions The sealers evaluated in this study had different radiopacities. However, except for the glass-ionomer-based sealer, all materials had radiopacity values above the minimum recommended by the ISO standard.

Comparative assessment of the flow rate of root canal sealers

OBJETIVO: Este estudo avaliou o escoamento do Acroseal, AH Plus, Endomethasone N, Sealapex e ActiV GP de acordo com a especificação ISO 6876/2001. METODOLOGIA: Um volume de 0,05 mL do cimento manipulado de acordo com as recomendações do fabricante foi colocado numa placa de vidro. Aos 180±5 s após o início da espatulação, uma segunda placa de vidro foi colocada sobre o cimento, seguida por um peso de massa de 100 g para fazer um total de 120±2 g. Dez minutos após o começo da manipulação o peso foi removido e o valor do diâmetro do disco de cimento foi mensurado. A média de 3 mensurações para cada cimento foi tomada como o escoamento do material. Os dados foram comparados estatisticamente pelos testes ANOVA e Tukey. RESULTADOS: Os escoamentos obtidos foram: Acroseal 21.,4 mm, AH Plus 22,72 mm, ActiV GP 24,90 mm, Endomethasone N 18,76 mm e Sealapex 25,15 mm. CONCLUSÃO: Apenas o Endomethasone N não se enquadrou na especificação ISO a qual requer que o cimento tenha um diâmetro não inferior a 20 mm. O Sealapex alcançou o melhor escoamento, mas não foi estatisticamente diferente do Activ GP e AH Plus (P>0,05).

Radiopacity evaluation of new root canal filling materials by digitalization of images

The aim of this study was to evaluate the radiopacity of five root canal filling materials (AH Plus, Intrafill, Roeko Seal, Epiphany, and EndoRez). Following the International Organization of Standardization 687612001, five circular specimens (10 X 1 mm) were made from each material. After the material set, radiographs were made using occlusal film and a graduated aluminum step-wedge varying in thickness from 2 to 16 mm. The dental X-ray unit (GE1000) was set at 50 Kvp, 10 mA, 18 pulses/second, and distance of 33.5 cm. The radiographs were digitized, and the radiopacity was compared with the aluminum step-wedge, using WIXWIN-2000 software (Gendex). Data (mm Al) were analyzed using ANOVA and Tukey tests. AH Plus and Epiphany were the most radiopaque materials (9.8 and 8.8 mm Al, respectively), followed by EndoRez (7.2 mm Al). Roeko Seal and Intrafill presented the lowest radiopacity values (5.7 and 6.1 mm Al, respectively). Although the materials evaluated demonstrated different radiopacities, all had values above the minimum recommended by the international Organization of Standardization.

Efficacy of NiTi rotary instruments in removing calcium hydroxide dressing residues from root canal walls

The aim of this study was to evaluate the efficacy of three rotary instrument systems (K3, ProTaper and Twisted File) in removing calcium hydroxide residues from root canal walls. Thirty-four human mandibular incisors were instrumented with the ProTaper System up to the F2 instrument, irrigated with 2.5% NaOCl followed by 17% EDTA, and filled with a calcium hydroxide intracanal dressing. After 7 days, the calcium hydroxide dressing was removed using the following rotary instruments: G1 - NiTi size 25, 0.06 taper, of the K3 System; G2 - NiTi F2, of the ProTaper System; or G3 - NiTi size 25, 0.06 taper, of the Twisted File System. The teeth were longitudinally grooved on the buccal and lingual root surfaces, split along their long axis, and their apical and cervical canal thirds were evaluated by SEM (×1000). The images were scored and the data were statistically analyzed using the Kruskall Wallis test. None of the instruments removed the calcium hydroxide dressing completely, either in the apical or cervical thirds, and no significant differences were observed among the rotary instruments tested (p > 0.05).

pH, Calcium Ion Release, and Setting Time of an Experimental Mineral Trioxide Aggregate-based Root Canal Sealer

Introduction: An experimental mineral trioxide aggregate sealer (MTAS) has been developed for use as a root canal sealer. The aim of this study was to evaluate the setting time, pH, and calcium ion release of MTAS compared with white Portland cement (CPB-40; Votorantin Cimentos, Camargo Correa SA, Pedro Leopoldo, MG, Brazil), white MTA Angelus (MTA; Angelus, Londrina, PR, Brazil), and AH Plus (Dentsply DeTrey, Konstanz, Germany). Methods: For the evaluation of setting time, each material was analyzed using Gilmore-type needles. Polyethylene tubes with the materials were immersed in distilled water for the measurement of pH (digital pH meter) and calcium release (atomic absorption spectrophotometry). The evaluations were performed at 3, 6, 12, 24, and 48 hours and 7, 14, and 28 days. Data were analyzed by analysis of variance and the Tukey test at 5% significance level. Results: MTAS showed higher calcium release at all experimental periods, a greater increase in pH up to 48 hours and the longest setting time. Conclusions: MTAS presented favorable properties for its indication as a root canal sealer. (J Endod 2011;37:844-846)

Enterococcus faecalis leakage of root canal sealers: an ex vivo study

The aim of this ex vivo study was to evaluate bacterial penetration after filling root canals using 3 different techniques. Three experimental groups of 25 teeth each, obturated with lateral-warm-vertical condensation of gutta-percha, Microseal technique and EndoREZ (R) system, respectively, were tested in a split chamber model system using Enterococcus faecalis and monitored for 180 days to determine bacterial penetration. A statistical analysis was performed using the Kaplan-Meier method. Median survival time was 25 days for Microseal system, 41 for lateral-warm-vertical condensation and 81 for EndoREZ (R). Significant differences were demonstrated between Microseal and EndoREZ (R) (p<0.001) and between Microseal and lateral-warm-vertical condensation technique (p<0.05). No statistically significant differences were observed between EndoREZ (R) and lateral-warm-vertical condensation. After 180 days of assessment, 20% of the EndoREZ (R) samples resisted bacterial penetration and furthermore, the EndoREZ (R) system has the potential to be a filler system compatible with other currently used systems.