Antibacterial Properties of Chitosan Nanoparticles and Propolis Associated with Calcium Hydroxide against Single- and Multispecies Biofilms: An In Vitro and In Situ Study.

INTRODUCTION: The aim of this study was to evaluate the efficacy of chitosan nanoparticles (CNPs) and ethanolic propolis extract (EPE) incorporated into a calcium hydroxide paste (Ca[OH]2) to kill bacterial biofilms. METHODS: Human root canal dentin was infected with Enterococcus faecalis for 21 days and also intraorally for 48 hours followed by incubation in brain-heart infusion for 48 hours to standardize biofilm growth. Ca(OH)2 pastes associated or not with CNPs or EPE were tested on biofilms for 7 and 14 days. Distilled water was used for control purposes. After the treatment procedures, microbiological analysis was performed to determine the reduction in E. faecalis colonies. Confocal microscopy was used to determine the percentage of cell viability in polymicrobial biofilms before and after the exposure to the experimental intracanal medications. RESULTS: All experimental pastes were able to significantly reduce the E. faecalis colony-forming units (CFU) after 7 or 14 days (P < .05). However, the CFU reduction was significantly improved when CNPs were incorporated into the Ca(OH)2 paste (P < .05). The multispecies biofilms treated with Ca(OH)2 showed similar percentages of bacterial viability to the control regardless of the exposure time (P > .05). The viable cell count significantly dropped in the Ca(OH)2/CNPs groups for both 7 and 14 days (P < .05), whereas the Ca(OH)2/EPE groups were only effective in eliminating bacteria during the first 7 days of treatment (P < .05). CONCLUSIONS: Incorporating CNPs into pastes of Ca(OH)2 could potentially be beneficial when using interappointment intracanal medications because of their ability to kill bacteria in short- and long-term exposure.

Preparation of Oval-shaped Canals with TRUShape and Reciproc Systems: A Micro-Computed Tomography Study Using Contralateral Premolars.

INTRODUCTION: The purpose of this study was to compare the shaping properties of TRUShape and Reciproc systems during preparation of oval-shaped canals from contralateral teeth by using micro-computed tomography scanning. METHODS: Thirteen pairs of freshly extracted contralateral mandibular premolars with a single oval-shaped canal were selected and divided into 2 groups according to the root canal instrumentation technique, TRUShape and Reciproc. The final apical size of instrumentation was 40/.06 for both systems. Data were statistically analyzed for the increase in canal volume and surface area and the amount of unprepared areas promoted by the 2 systems. RESULTS: Preparation with both systems significantly increased the volume and area of the canals (P < .001), with no significant differences between them (P > .05). When the full canal length was evaluated, the amount of uninstrumented areas was significantly larger for Reciproc (30%) than TRUShape (24%) (P < .05). However, analysis restricted to the apical 4-mm segment revealed no statistically significant difference in untouched areas (25% for Reciproc and 20% for TRUShape) (P > .05). CONCLUSIONS: Both instrument systems behaved similarly in promoting the increase of root canal volume and surface area. When the full canal length was evaluated, TRUShape instruments showed less unprepared areas than Reciproc. However, this difference did not occur for the apical part of the root canal. None of the techniques could completely prepare oval-shaped root canals.

Changes in mandibular incisor position and arch form resulting from Invisalign correction of the crowded dentition treated nonextraction.

OBJECTIVE: To investigate changes in mandibular incisor position resulting from Invisalign correction of the crowded dentition without extraction. MATERIALS AND METHODS: A retrospective chart review was completed on 61 adult White patients. Patients were categorized into three groups based on the value of pretreatment crowding of the lower dentition: 20 mild (2.0-3.9 mm), 22 moderate (4.0-5.9 mm), and 19 severe (>6.0 mm). Cephalometric radiographs were measured to determine lower incisor changes. Interproximal reduction and changes in arch width were also measured. Statistical evaluation of T0 and T1 values using paired t-tests and analysis of covariance were applied to evaluate mean value changes. RESULTS: Lower incisor position and angulation changes were statistically significant in the severe crowding group. There were no statistically significant differences in lower incisor position between the mild and moderate crowding groups. There was a statistically significant increase in buccal expansion in each of the three groups. CONCLUSIONS: Invisalign(®) treatment can successfully resolve mandibular arch crowding using a combination of buccal arch expansion, interproximal reduction, and lower incisor proclination. When there is <6 mm of crowding, lower incisor position remained relatively stable. The lower incisors proclined and protruded in the more severely crowded dentitions (>6 mm).

Efficacy of ProTaper NEXT Compared with Reciproc in Removing Obturation Material from Severely Curved Root Canals: A Micro-Computed Tomography Study.

INTRODUCTION: The aim of this study was to compare the remaining root canal obturation, volume of dentin removed, and apical transportation after retreatment of severely curved root canals by using Reciproc (REC) or ProTaper NEXT (PTN) systems. METHODS: Twenty-eight mesial canals of mandibular molars were instrumented and then obturated with gutta-percha and sealer and allocated into 2 balanced groups (n = 14), the REC group (R25 file) and the PTN group (X3 and X2 files). Micro-computed tomography analysis was performed to assess the percentage of residual obturation material, the amount of dentin removed, and apical transportation. The effective time for the removal of obturation and procedural errors were recorded. RESULTS: Obturation was effectively removed from the root canal in the REC and PTN groups (P ≤ .001), and the percentages of remaining obturation material were similar between both groups (84.8% PTN vs 86.5% REC) (P > .05). The amount of dentin removed (3.17 ± 2.64 mm(3) PTN versus 3.50 ± 2.82 mm(3) REC), apical transportation (at 1 mm: 0.096 ± 0.189 mm PTN versus 0.093 ± 0.186 mm REC; at 3 mm: 0.059 ± 0.069 mm PTN versus 0.082 ± 0.080 mm REC; at 5 mm: 0.097 ± 0.093 mm PTN versus 0.133 ± 0.138 mm REC), and the working time (269.69 ± 19.25 seconds PTN versus 268.62 ± 16.37 seconds REC) were also similar in both groups (P > .05). One file fractured in the REC group. CONCLUSIONS: Both systems were equally effective in the removal of obturation from severely curved canals and can be used for retreatment. Neither system could completely remove the obturation material; therefore, additional techniques are needed to improve cleaning of the root canal.

Sealing ability of mineral trioxide aggregate (MTA) combined with distilled water, chlorhexidine, and doxycycline.

The aim of this study was to evaluate the sealing ability of mineral trioxide aggregate (MTA Bio) combined with different mixing agents (distilled water, chlorhexidine, doxycycline), used as an apical root-end filling material. Forty-two extracted human teeth were divided into three groups (n = 12); six teeth were used as controls. Root-ends were resected at 90 degrees, 3 mm from the apex. Root-end cavities were prepared using ultrasonic tips and filled with MTA Bio plus distilled water, 2% chlorhexidine solution, or 10% doxycycline solution. Apical sealing was assessed by microleakage of 50% silver nitrate solution. Roots were longitudinally sectioned in a buccolingual plane and analyzed using an operating microscope (20× magnification). Depth of dye leakage into the dentinal walls was measured in millimeters. Results were analyzed using ANOVA and Tukey's test (P = 0.05). MTA Bio plus distilled water showed significantly higher mean leakage results (1.06 mm) when compared with MTA Bio plus doxycycline (0.61 mm), and higher, although not significant, results when compared with MTA Bio plus chlorhexidine (0.79 mm). In conclusion, replacing distilled water with two biologically active mixing agents (doxycycline and chlorhexidine) did not alter the sealing properties of MTABio. The antimicrobial properties of these combinations should be further investigated.

Assessment of the separation incidence of mtwo files used with preflaring: prospective clinical study.

INTRODUCTION: The Mtwo rotary system was designed to be used at full length without performing previous cervical enlargement or creating a manual glide path. However, to our knowledge, no study has investigated whether preflaring influences instrument fatigue. The purpose of this clinical study was thus to evaluate the incidence of separation of Mtwo instruments during the preparation of mandibular and maxillary molars and bicuspids that was preceded by cervical preflaring. METHODS: A total of 556 treatments were performed by 6 endodontists after calibration. Cervical enlargement and exploration with hand files were undertaken before using the rotary files. The canals were negotiated with small K-type hand files. Cervical and middle thirds were prepared with hand files and Gates-Glidden burs. Irrigation was performed with 2 mL of 2.5% NaOCl after each instrument. The working length was established, and the apical third was prepared with Flexofiles until a #15 file could reach the working length, establishing a glide path. The Mtwo instruments were used following manufacturer's recommendations and disposed of after being used in 5 teeth. Each file was examined under ×8 magnification after use. In cases of file deformation or separation, the entire file kit was no longer used, except when using the 10.04 file. Because of its high failure rate, which is well-established in the related literature, this instrument could be replaced at any time. RESULTS: Separation and deformation rates were 1.98% and 28.78%, respectively. Ten of the total separations observed occurred with the 10.04 file (90.01%) and one with the 15.05 file (9.09%). CONCLUSIONS: The use of Mtwo rotary instruments preceded by cervical preflaring with manual files and Gates-Glidden burs provides a low separation incidence.

Single-session use of mineral trioxide aggregate as an apical barrier in a case of external root resorption.

External root resorption may occur as a consequence of trauma, orthodontic treatment, bacterial infection or incomplete sealing of the root canal system (bacterial re-infection), and lead to crater formation on the resorbed apex. This would deform the root apex surface, and cause loss of apical constriction. Depending on the extent of the resorptive process, different treatment regimens have been proposed. A 34-year-old male patient presented with an intra-radicular retainer and an inadequate filling on tooth #21, as well as a radiographic image suggesting periapical bone rarefaction. After root canal retreatment, the defect was accessed coronally. The resorption area was chemo-mechanically debrided and since the apical end was very wide, a calcium sulphate matrix was made. Mineral trioxide aggregate (MTA) was used to fill the resorptive defect, and the coronal access was temporarily sealed. After 24 h, the quality of the apical seal was evaluated with the aid of an operating microscope, and then the root canal system was filled. A 12-month follow-up radiograph showed adequate repair of the resorption. Clinically, the tooth was asymptomatic. We concluded that MTA can be successfully used to avoid overextension of the filling material when treating a tooth with external resorption.

Heparin quality control in the Brazilian market: implications in the cardiovascular surgery.

INTRODUCTION: The change in the heparin solution trade mark in Brazil that had been commonly used in cardiac surgery has shown increased number in the coagulopathy, re-exploration and other side effects in our Institution and others. METHODS: All four different heparin solutions available in the Brazilian market were studied in the Connective Tissue Lab, HUCFF, UFRJ and compared to the Liquemine (out of the market) and the international control solution. All samples were evaluated by magnetic nuclear resonance as well as their anticoagulant effectiveness. RESULTS: There were significant differences among them regarding the anticoagulant activity. It was also observed contamination with other dermatan sulfate, samples chemically degraded and with significant change in the molecular weight. CONCLUSION: Among the studied samples, none of them can offer security in cardiac surgeries on pump. None of them has demonstrated similar quality to Liquemine, which is not available in the Brazilian market.

Controle da qualidade das preparações de heparina disponíveis no Brasil: implicações na cirurgia cardiovascular / Heparin quality control in the Brazilian market: implications in the cardiovascular surgery

INTRODUÇÃO: A mudança na marca da heparina rotineiramente utilizada nas cirurgias cardíacas no Brasil tem sido acompanhada por aumento do número de casos de discrasia sanguínea, aumento de reoperações e efeitos adversos em nossa Instituição e em outras. MÉTODOS: Foram avaliadas no Laboratório de Tecido Conjuntivo do HUCFF/UFRJ, quatro preparações disponíveis e comparadas à heparina retirada do mercado (Liquemine) e ao padrão de controle internacional. As preparações de heparina foram submetidas à ressonância nuclear magnética para avaliação da integridade estrutural, bem como avaliação de sua eficácia anticoagulante. RESULTADOS: Houve diferença significativa quanto à atividade anticoagulante entre as amostras. Também se observou a presença de contaminação com dermatam sulfato, amostras degradadas quimicamente e com significativa alteração do peso molecular. CONCLUSÃO: Das amostras estudadas, nenhuma atendeu aos requisitos de segurança para utilização em cirurgias cardíacas com circulação extracorpórea. Nenhuma delas apresentou a qualidade semelhante ao Liquemine, não mais disponível no mercado brasileiro.

INTRODUCTION: The change in the heparin solution trade mark in Brazil that had been commonly used in cardiac surgery has shown increased number in the coagulopathy, re-exploration and other side effects in our Institution and others. METHODS: All four different heparin solutions available in the Brazilian market were studied in the Connective Tissue Lab, HUCFF, UFRJ and compared to the Liquemine (out of the market) and the international control solution. All samples were evaluated by magnetic nuclear resonance as well as their anticoagulant effectiveness. RESULTS: There were significant differences among them regarding the anticoagulant activity. It was also observed contamination with other dermatan sulfate, samples chemically degraded and with significant change in the molecular weight. CONCLUSION: Among the studied samples, none of them can offer security in cardiac surgeries on pump. None of them has demonstrated similar quality to Liquemine, which is not available in the Brazilian market.