Montse Mercadé

Influence of Light and Oxygen on the Color Stability of Five Calcium Silicate–based Materials

INTRODUCTION Difficult handling, long setting time, and potential discoloration are important drawbacks of white mineral trioxide aggregate (WMTA). The development of Biodentine, a recently developed calcium silicate-based material (CSM), has overcome some of these shortcomings; however, there are no available data on its color stability. A previous study showed that WMTA discolors under light irradiation in an oxygen-free environment. The present study evaluated the influence of light irradiation and oxygen on the color stability of 5 CSMs. METHODS Fifteen samples of 5 CSMs (ProRoot WMTA, Angelus WMTA, White Portland Cement [PC], PC with bismuth oxide, and Biodentine) were divided into 5 groups. Each group was exposed to different oxygen and light conditions. A spectrophotometer was used to determine the color of each specimen at 0, 120 seconds, and 5 days. Data were analyzed by using analysis of variance and Tukey honestly significant difference test. RESULTS The materials PC with bismuth oxide, Angelus WMTA, and ProRoot WMTA showed dark discoloration after light irradiation in an oxygen-free environment, which was statistically significantly different from Biodentine and PC. In groups that were exposed to no light irradiation or to an oxygen atmosphere, all materials showed color stability over time, and no significant differences were observed among them. PC and Biodentine maintained color stability in all conditions over time and showed no significant differences. CONCLUSIONS The combination of light and anaerobic conditions (similar to those in clinical situations) results in differences in color of the tested CSMs during a period of 5 days, of which Biodentine and PC demonstrated color stability.

Evaluating the Periapical Status of Teeth with Irreversible Pulpitis by Using Cone-beam Computed Tomography Scanning and Periapical Radiographs

INTRODUCTION The purpose of this study was to compare the prevalence of apical periodontitis (AP) on individual roots of teeth with irreversible pulpitis viewed with periapical (PA) radiographs and cone-beam computed tomography (CBCT) scans. METHODS PA radiographs and CBCT scans were taken of 138 teeth in 130 patients diagnosed with irreversible pulpitis (symptomatic and asymptomatic). Two calibrated examiners assessed the presence or absence of AP lesions by analyzing the PA and CBCT images. A consensus was reached in the event of any disagreement. The data were analyzed using the hypothesis test, and significance was set at P ≤ .05. RESULTS Three hundred seven paired roots were assessed with both PA and CBCT images. A comparison of the 307 paired roots revealed that AP lesions were present in 10 (3.3%) and absent in 297 (96.7%) pairs of roots when assessed with PA radiography. When the same 307 sets of roots were assessed with CBCT scans, AP lesions were present in 42 (13.7%) and absent in 265 (86.3%) paired roots. The prevalence of AP lesions detected with CBCT was significantly higher in the symptomatic group compared with the asymptomatic group (P < .05). An additional 22 roots were identified with CBCT alone. CONCLUSIONS The present study highlights the advantages of using CBCT for detecting AP lesions, especially in teeth with symptomatic irreversible pulpitis.

Efficacy of three different rotary files to remove gutta-percha and Resilon from root canals.

AIM To evaluate the efficacy of ProTaper Retreatment files, Mtwo Retreatment files and Twisted Files for removal of gutta-percha and Resilon in straight root canals. METHODOLOGY Ninety single root canals were instrumented and randomly allocated into 6 groups of 15 specimens each with regards to the filling material and instruments used. Group 1: gutta-percha/ProTaper; Group 2: Resilon/ProTaper; Group 3: gutta-percha/Mtwo; Group 4: Resilon/Mtwo; Group 5: gutta-percha/Twisted Files; Group 6: Resilon/Twisted Files. For all roots, the following data were recorded: procedural errors, duration of retreatment, canal wall cleanliness through optical microscope and cone beam computed tomography (CBCT). Data were statistically analysed, and the level of significance was set at P=0.05. RESULTS No system completely removed the root filling material from root canal walls. No significant differences were observed between the rotary systems in terms of the area of filling material left within the canals (P>0.05). There were statistically significant differences between the filling materials: Resilon/Real Seal had less residual material than gutta-percha/AH plus (CBCT: P=0.01; microscope: P=0.018). Mtwo Retreatment files were more rapid when removing filling material than ProTaper Retreatment files (P=0.19) and Twisted Files (P=0.04). CONCLUSIONS No system removed the root filling materials entirely. Mtwo Retreatment files required less time to remove root filling material than the other instruments. Resilon was removed significantly better from the canal walls than gutta-percha, irrespective of the rotary instruments used.

Evaluation of the Raypex 5 and the Mini Apex Locator: An In Vivo Study

INTRODUCTION The purpose of this study was to compare the accuracy in vivo of 2 electronic apex locators (EALs), the Raypex 5 and the Mini Apex Locator. METHODS The working length (WL) was determined electronically for 40 human root canals by using a K-file and 1 of the 2 EALs. The files were fixed at the WL, and the teeth were extracted. The apical 4 mm of each canal was trimmed to expose the file tip. The samples were observed under a scanning electron microscope, and the distance from the file tip to the point 0.5 mm coronal to the major foramen (the final WL) was measured. The data were analyzed by using Student t test, and significance was set at P < .05. RESULTS No statistically significant differences were found between the Raypex 5 and the Mini Apex Locator devices. The mean distance from the final WL to the file tip was 0.174 ± 0.38 mm for the Raypex 5 and 0.286 ± 0.30 mm for the Mini Apex Locator. In determining the final WL, the Raypex 5 was accurate 75% of the time to ± 0.5 mm and 100% of the time to ± 1 mm, whereas the Mini Apex Locator was accurate 77.8% of the time to ± 0.5 mm and 100% of the time to ± 1 mm. CONCLUSIONS Under the in vivo conditions of this study, no statistically significant differences were observed between the Raypex 5 and the Mini Apex Locator EALs.

An evaluation of the periapical status of teeth with necrotic pulps using periapical radiography and cone-beam computed tomography

AIM To evaluate the presence or absence of periapical (PA) radiolucencies on individual roots of teeth with necrotic pulps, as assessed with digital PA radiographs and cone-beam computed tomography (CBCT). METHODOLOGY Digital PA radiographs and CBCT scans were taken from 161 endodontically untreated teeth (from 155 patients) diagnosed with non-vital pulps (pulp necrosis with normal PA tissue, symptomatic apical periodontitis, asymptomatic apical periodontitis, acute apical abscess and chronic apical abscess). Images were assessed by two calibrated endodontists to analyse the radiographic PA status of the teeth. A consensus was reached in the event of any disagreement. The data were analysed using a McNemars test, and significance was set at P ≤ 0.05. RESULTS Three hundred and forty paired images of roots were assessed with both digital PA radiographs and CBCT images. Fifteen additional roots were identified with CBCT. PA radiolucencies were present in 132 (38.8%) roots when assessed with PA radiographs, and in 196 (57.6%) roots when assessed with CBCT. This difference was statistically significant (P < 0.05). In teeth diagnosed with pulp necrosis, symptomatic apical periodontitis or acute apical abscess, CBCT images revealed a statistically larger number of PA radiolucencies than did PA radiographs (P < 0.05). No statistical differences were observed between PA radiographs and CBCT in teeth classified with asymptomatic apical periodontitis (P = 0.31) or chronic apical abscess (P = 1). CONCLUSIONS Unlike PA radiographs, CBCT revealed a higher prevalence of PA radiolucencies when endodontically untreated teeth with non-vital pulps were examined.

Managing severe curvature of radix entomolaris: three-dimensional analysis with cone beam computed tomography.

AIM To present a case of a mandibular first molar with an additional distolingual root [radix entomolaris (RE)] and to discuss the use of cone beam computed tomography (CBCT) for its identification and management during root canal treatment. SUMMARY A 52-year-old Caucasian woman was referred for root canal treatment of the right mandibular first molar (tooth 46). After clinical and radiographic examination, a symptomatic irreversible pulpitis was diagnosed. Three periapical radiographs with different horizontal angulations revealed the presence of an additional distolingual root. This extra root, termed RE, has an incidence of <5% in the Caucasian population. A CBCT examination was also taken, which revealed a severe root canal curvature, especially in the middle third, of this supernumerary root. CBCT provided more accurate information in terms of RE inclination and root canal curvature before commencing root canal treatment. The conventional access opening was modified into a more trapezoidal cavity, and five root canals were found. All canals were instrumented with new nickel-titanium (NiTi) files to reduce the risk of fractured instruments. After preparation, the root canals were filled using thermoplastified techniques. The 1-year follow-up periapical radiographs and CBCT images revealed a continuous periodontal space with no signs of apical periodontitis. KEY LEARNING POINTS • Cone beam computed tomography imaging is useful in identifying the root canal system and the surrounding structures. • An accurate detection of supernumerary roots, such as RE, can avoid complications during and after root canal treatment. • The analysis of root canal curvature is important because instrument fracture has been linked to angle and radius of curvature. • The use of new instruments can reduce the incidence of instrument fracture.

Mandibular first molars with disto-lingual roots: review and clinical management.

The purpose of this review was (i) to conduct a literature review on the prevalence and morphologic classification of mandibular first molars with disto-lingual (DL) roots, and (ii) to discuss the clinical approach to diagnosis and root canal treatment of these teeth. A search was carried out on electronic (MEDLINE, PubMed and Cochrane) and hand databases, which covered all publications from 1970 to December 2011. Two reviewers independently assessed the studies and recorded type of study, origin and sample sizes, number of teeth with three roots and type of root canal configuration. Forty-five studies were identified with a total of 19,056 mandibular first molar teeth. The frequency of DL roots was 14.4% and was associated with certain ethnic populations. The most common canal configuration of mesial and distal roots was Vertucci types IV and I, respectively. No significant differences were observed in the prevalence of DL roots according to gender. Variable results related to side were observed as well as a trend in bilateral occurrence. The root length of the DL roots was in general shorter than that of the disto-buccal roots (DB). Most DL roots had a greater angle of curvature and a smaller radius of curvature in a bucco-lingual orientation. The best methods to identify DL roots are a 25° mesial parallax periapical radiograph or cone-beam computed tomography (CBCT). A trapezoidal shape access cavity is desirable to locate the orifice of the DL canal. Clinicians should be aware of the variable furcation levels during coronal pre-flaring or post-space preparation to avoid furcal/strip perforations and a weakening of DL roots.

Centring ability and apical transportation after overinstrumentation with ProTaper Universal and ProFile Vortex instruments

AIM  To evaluate morphological changes to the major foramen after overinstrumentation with ProTaper Universal and ProFile Vortex Ni-Ti rotary instruments. METHODOLOGY Twenty-eight mesiobuccal canals of maxillary and mandibular first molars were divided into two groups of 14 canals each. The root canals were prepared with ProTaper Universal or ProFile Vortex instruments. ProTaper and Vortex instruments were used until the file tip protruded 1 mm beyond the working length (0.5 mm beyond the major foramen). The major foramen was photographed before and after overinstrumentation with each file of the two systems used. The images were superimposed and evaluated using Adobe Photoshop. The parameters evaluated were canal transportation, centring ability and shape of the major foramen. Transportation and centring ability were calculated in two directions: the direction of maximum curvature (MC) and a direction vertical to the maximum curvature (VC). Measurements of canal transportation and centring ability were analysed by anova followed by post hoc least significance difference (LSD) multiple comparisons. RESULTS No significant differences were observed amongst the different instruments with respect to centring ability in either direction (P > 0.05). The F3 ProTaper Universal instrument was associated with a higher mean values for transportation in the direction of MC (P < 0.05) than the S1, S2 and F1 ProTaper Universal instruments and the size 15, 0.06 taper, size 20, 0.06 taper, and size 25, 0.06 taper ProFile Vortex instruments. The size 30, 0.06 taper ProFile Vortex instrument had a larger mean value for transportation in the direction of MC (P < 0.05) than the S1 ProTaper Universal and size 15, 0.06 taper ProFile Vortex instruments. The S1, S2, F1, F2 and F3 ProTaper Universal files and the size 15, 0.06 taper, size 20, 0.06 taper, size 25, 0.06 taper, and size 30, 0.06 taper ProFile Vortex files produced an oval foramen in 71%, 71%, 85%, 85%, 71%, 71%, 85%, 85% and 89% of the cases, respectively. CONCLUSIONS In most samples, the ProTaper Universal and ProFile Vortex files produced transportation of the major foramen and created an oval-shaped major foramen after overinstrumentation.

Antimicrobial efficacy of 4.2% sodium hypochlorite adjusted to pH 12, 7.5, and 6.5 in infected human root canals

OBJECTIVE The purpose of this study was to determine the antimicrobial efficacy of sodium hypochlorite adjusted to pH 12, 7.5, and 6.5 in human root canals infected by Enterococcus faecalis. STUDY DESIGN One hundred sixty-five human single-rooted teeth were prepared and inoculated with E. faecalis for 48 h. Teeth were divided into 3 experimental groups according to the irrigation pattern used: group 1, 4.2% NaOCl pH 12; group 2, 4.2% NaOCl pH 7.5; and group 3, 4.2% NaOCl pH 6.5. Samples from the root canals were collected, and bacterial growth was analyzed by turbidity of the culture medium. RESULTS None of the irrigating solutions used in this study demonstrated 100% effectiveness against E. faecalis. The antibacterial effectiveness of 4.2% NaOCl at pH 6.5 was significantly increased (P = .03) compared with 4.2% NaOCl at pH 12 (chi-squared test: P < .05). CONCLUSION Bactericidal activity of NaOCl solution is enhanced by weak acidification of 4.2% NaOCl solution at pH 6.5.

Horizontal root fracture treated with MTA, a case report with a 10-year follow-up.

Root fractures occur more frequently in fully erupted permanent teeth with closed apices in which the completely formed root is solidly supported in the bone and periodontium. The consequences can be complex because of combined damage to the pulp, dentine, cementum, bone, and periodontium. Management of horizontal root fractures and lateral luxation depends on several factors, with the result that various clinical modalities have been suggested. This case report describes the treatment and 10-year follow-up of two maxillary central incisors, one with horizontal root fracture and the other with lateral luxation, treated with mineral trioxide aggregate and root canal treatment, respectively.