Influence of different agitation techniques on bacterial reduction in curved root canals.

The aim of this study was to evaluate the influence of agitation techniques on bacterial reduction in curved root canals. Eighty human mandibular molars were prepared, inoculated with Enterococcus faecalis and incubated at 37°C for 60 days. Then, specimens were randomly separated into two test groups (n = 36) and two control groups (n = 04) according to agitation technique: Passive ultrasonic irrigation (PUI, Irrisonic) and XP-endo Finisher (XPF). Microbial samples were collected before and after instrumentation and after final agitation using sterile paper points. Bacterial growth was analysed by turbidity of culture medium and UV spectrophotometry. The Wilcoxon rank test was used for the paired analysis, while the Mann-Whitney U-test was used for the non-paired analysis. The samples collected after final agitation were significantly different between test groups (p < 0.05). Bacterial reduction was greater in the PUI than in the XPF (p < 0.05) group. The irrigant agitation provided significant bacterial reduction. The use of the PUI showed better results.

Effect of different diode laser wavelengths on root dentin decontamination infected with Enterococcus faecalis.

The objective of this study was to evaluate the antibacterial effect and the ultrastructural alterations of diode laser with different wavelengths (808nm and 970nm) and its association with irrigating solutions (2.5% sodium hypochlorite and 2% chlorhexidine) in root dentin contaminated by a five days biofilm. Thirteen uniradicular teeth were sectioned into 100 dentin intraradicular blocks. Initially, the blocks were immersed for 5min in 17% EDTA and washed with distilled water for 5min, then samples were sterilized for 30min at 120°C. The dentin samples were inoculated with 0.1mL of E. faecalis suspension in 5mL BHI (Brain Heart Infusion) and incubated at 37°C for 5days. After contamination, the specimens were distributed into ten groups (n=10) according to surface treatment: GI - 5mL NaOCl 2.5%, GII - 5mL NaOCl 2.5%+808nm diode (0.1W for 20s), GIII - 5mL NaOCl 2.5%+970nm diode (0.5W for 4s), GIV - 808nm diode (0.1W for 20s), GV - 970nm diode (0.5W for 4s), GVI - CHX 2%, GVII - CHX 2%+808nm diode (0.1W for 20s), GVIII - CHX 2%+970nm diode (0.5W for 4s), GIX - positive control and GX - negative control. Bacterial growth was analyzed by turbidity and optical density of the growth medium by spectrophotometry (nm). Then, the specimens were processed for analysis ultrastructural changes of the dentin surface by SEM. The data was subject to the One-way ANOVA test. GI (77.5±12.1), GII (72.5±12.2), GIII (68.7±8.7), GV (68.3±8.7), GVI (62.0±5.5) and GVII (67.5±3.3) were statistically similar and statistically different from GIV (58.8±25.0), GVIII (59.2±4.0) and control groups (p<0.05). SEM analysis showed a modified amorphous organic matrix layer with melted intertubular dentin when dentin samples were irradiated with 970nm diode laser; erosion of the intertubular dentin in blocks submitted to 808nm diode laser irradiation; and an increased erosion of the intertubular dentin when 2.5% NaOCl was associated to the different wavelengths lasers. All the therapeutic protocols were able to reduce the bacterial contingent in dentin blocks, and the association of diode laser and solutions did not significantly improve the reduction of the bacterial contingent.

The Influence of Cervical Preflaring on the Amount of Apically Extruded Debris after Root Canal Preparation Using Different Instrumentation Systems.

INTRODUCTION: The objective of this study was to evaluate the influence of cervical preflaring on the amount of apically extruded debris after root canal preparation using different instrumentation systems. METHODS: One hundred eighty human maxillary central incisors were selected and randomly divided into 12 groups (n = 15). Root canals were instrumented according to manufacturers' instructions using 2 reciprocating single-file systems (Reciproc [VDW, Munich, Germany] and WaveOne [Dentsply Maillefer, Ballaigues, Switzerland]), 3 full-sequence rotary systems (ProTaper Universal [Dentsply Maillefer], ProTaper Next [Dentsply Tulsa Dental, Tulsa, OK], and ProFile [Dentsply Maillefer]), and K-files (Dentsply Maillefer) driven by an oscillatory system with and without cervical preflaring. Bidistilled water was used as irrigant. Apically extruded debris was collected in preweighed glass vials using the Myers and Montgomery method. After drying, the mean weight of debris was determined using a microbalance. Kolmogorov-Smirnov and Levene tests followed by the Tukey post hoc test were used for statistical analysis. RESULTS: K-files produced significantly more debris than all of the other systems (P < .05). For all systems, cervical preflaring reduced the amount of apically extruded debris when compared with no cervical preflaring (P < .05). CONCLUSIONS: All of the systems extruded debris, irrespective of the preparation technique used (with or without cervical preflaring). Cervical preflaring was associated with the extrusion of smaller quantities of apical debris.

Antibacterial Potential of 2.5% Sodium Hypochlorite in Distinct Irrigation Protocols on Enterococcus faecalis Biofilm.

OBJECTIVE: The aim of this study was to evaluate the effect of irrigation methods on antibacterial potential of 2.5% NaOCl on Enterococcus faecalis biofilm. MATERIALS AND METHODS: Enterococcus faecalis biofilms were prepared during 60 days on 48 human root canals and randomized into control and experimental groups using positive and negative pressure irrigation. Bacterial growth was analyzed using turbidity of culture medium followed by UV spectrophotometry, and scanning electron microscopy (SEM) analyses were performed. Mean and standard deviations were used for evaluate the mean optical densities associated to the number of bacteria present culture, and Scheirer-Ray-Hare (an extension of the Kruskal-Wallis test) and Tamhane test to analyze the SEM images in the groups and thirds. Significance was set at 5%. RESULTS: Enterococcus faecalis was still present after root canal cleaning regardless of irrigation methods or bacterial identification methods. CONCLUSION: Positive and negative pressure irrigation protocols using 2.5% NaOCl show a similar capacity to reduce E. faecalis in infected root canals.

Chemical and structural characterization of glass ionomer cements indicated for atraumatic restorative treatment.

Glass ionomer cements (GICs) are restorative materials, which clinical use has increased significantly during the last decade. The aim of the present study was to analyze the chemical constitution and surface morphology of four glass ionomer cements: Maxxion R, VitroFill, Vidrion R and Vitremer. Twelve polyethylene tubes with an internal diameter of 3 and 3 mm in length were prepared, filled and then transferred to a chamber with 95% relative humidity and a temperature of 37°C. The surface morphology of the tested materials was examined by scanning electron microscopy (SEM) and main components were investigated by energy-dispersive X-ray microanalysis (EDX). Scanning electron microscopy revealed irregular and rough external surface. Cracking was not observed. The main constituents were found to be aluminum, silicon, calcium, sodium and fluoride. Phosphorus, sulfur and barium were only observed in Vidrion R, while chlorine were only observed in Maxxion R. Elemental mapping of the outer surface revealed high concentration of aluminum and silicon. Significant irregularities on the surface of the tested materials were observed. The chemical constitution of all GIC was similar.

10-year follow-up of calcifying odontogenic cyst in the periapical region of vital maxillary central incisor.

INTRODUCTION: Radiographic images may lead to misinterpretations of lesions of endodontic and nonendodontic origin. This report describes a case of a 10-year follow-up of a calcifying odontogenic cyst (COC) in the periapical region of a vital maxillary central incisor in a 9-year-old boy. METHODS: The patient revealed a history of a swelling in the periapical area of tooth #9. The patient denied any dental trauma or history of pain. Clinical examination revealed no mobility, but there was discrete discomfort when horizontal pressure was applied. Pulp vitality was present in all maxillary anterior teeth. Radiographs revealed an oval radiolucent lesion in the periapical region of maxillary central incisor. The therapeutic option was enucleation of the periapical lesion and histologic examination of the specimen. Microscopic findings suggested the diagnosis of a COC. RESULTS: At a follow-up visit 10 years after surgery, panoramic and periapical radiographs showed new bone formation; the patient did not have any pain, and pulp vitality was maintained in all teeth in this area. CONCLUSIONS: A COC should be part of the differential diagnosis of other jaw lesions, such as apical periodontitis. The definitive diagnosis of a COC can only be made after microscopic evaluation of the specimen. The follow-up is a helpful reference because it confirms the survival of pulp tissue and no recurrence of the COC.

8-year follow-up of central giant cell lesion mimicking apical periodontitis.

INTRODUCTION: Lesions of nonendodontic origin may mimic apical periodontitis. Central giant cell lesions (CGCLs) are aggressive or nonaggressive benign idiopathic intraosseous lesions of the jaw. This report describes a case of a CGCL in the periapical region of teeth #21-#26 of a 17-year-old female who sought orthodontic care because of a change in the position of tooth #23. METHODS: Clinical examination revealed mild facial asymmetry caused by increased volume in the mental region and cortical bone expansion but no cortical disruption. A panoramic radiograph showed a well-defined radiolucent osteolytic lesion involving teeth #21-#26. The cortical bone was not affected, and there was no root resorption. Incisional biopsy was performed, and the diagnosis was a CGCL. The lesion was enucleated surgically. CGCLs should be included in the differential diagnosis of jaw lesions that mimic apical periodontitis. RESULTS: The patient subsequently underwent orthodontic treatment successfully. CONCLUSIONS: The 8-year clinical and radiographic follow-up confirmed lesion remission, no recurrence, and pulp vitality of all teeth.

Autogenous premolar transplantation into artificial socket in maxillary lateral incisor site.

INTRODUCTION: Autogenous transplantation of a natural tooth to another site has significant advantages over dental implants, particularly in cases of agenesis, accidental tooth loss, or poor prognosis for the maintenance of tooth function. METHODS: This report describes a case of autogenous premolar transplantation into an artificial socket in the site of a missing maxillary lateral incisor in a 13-year-old girl. Clinical examination and radiography revealed tooth agenesis (#4, #10, #13, and #20) and microdontia (#7). The occlusion and skeletal maxillomandibular relations were normal. RESULTS: Tooth #29 was chosen for transplantation into the site of tooth #10 because of its size, stage of root formation, and possible closure of the spaces created by agenesis. CONCLUSIONS: Autogenous transplantation is a feasible alternative to dental implants in cases of tooth agenesis or tooth loss because of trauma. Autotransplantation was indicated in this case because it ensures the natural (facial) growth of the alveolar process and preserves the function of periodontal tissues. A multidisciplinary approach (ie, combining techniques from different dental specialties) was important for treatment success. Clinical and radiographic follow-up confirmed that the transplanted premolar was esthetically comparable with the lateral incisor and that root development and pulp canal obliteration were complete.

Method to evaluate inflammatory root resorption by using cone beam computed tomography.

INTRODUCTION: The aim of this study was to evaluate a method to measure inflammatory root resorption (IRR) by using cone beam computed tomography (CBCT) scans. METHODS: IRR sites were classified according to root third and root surface, and IRR extension was measured on the axial, transverse, and tangent views of 3-dimensional CBCT scans by using the Planimp software. A 5-point (0-4) scoring system was used to measure the largest extension of root resorption. A total of 48 periapical radiographs and CBCT scans originally taken from 40 patients were evaluated. The kappa coefficient was used to assess interobserver agreement and the chi(2) test to determine significant differences between the imaging methods. The level of significance was set at alpha = 1%. RESULTS: IRR was detected in 68.8% (83 root surfaces) of the radiographs and 100% (154 root surfaces) of the CBCT scans (P < .001). The extension of IRR was >1-4 mm in 95.8% of the CBCT images and in 52.1% of the images obtained by using the conventional method (P < .001). CONCLUSIONS: CBCT seems to be useful in the evaluation of IRR, and its diagnostic performance was better than that of periapical radiography.