A Comparative Evaluation of Push-Out Bond Strength of Six Different Root Canal Sealers: An In-Vitro Study.

BACKGROUND: Adhesiveness with radicular dentin is absent with gutta-percha, leading to microleakage and hence re-infection. Root canal sealer helps to achieve an adhesive interface between gutta-percha and root dentin thereby resisting the displacement forces during the functioning of teeth which is evaluated by the push-out test. The aim of this study is to compare the push-out bond strength and to assess the relative bond failure between dentin-sealer, sealer-main cone of (1) epoxy resin, (2) silicon, (3) mineral trioxide aggregate (MTA), (4) calcium hydroxide, (5) bioceramic, (6) zinc oxide eugenol containing root canal sealers. METHODOLOGY: Sixty human permanent lower premolars with one root were collected, disinfected, and decoronated at cemento-enamel junction. Instrumentation was done with a K3 40,0.06 Ni-Ti rotary file and obturated using the main cone and sealer. Based on the sealer utilized, six groups were created: Group 1: AH-Plus, Group 2: RoekoSeal, Group 3: MTA Fillapex, Group 4: Apexit, Group 5: Smart Paste Bio, and Group 6: Procosol. One slice each was obtained from the coronal, middle, and apicalsections of all the obturated canals. Push-out bond strength and failure modes were studied. Statistics involved analysis of variance (ANOVA) followed by the post hoc Tukey test. RESULTS: All three sections exhibited the highest strength for Smart Paste Bio sealer and the least was for RoekoSeal. With all the sealers, the apical section had the highest strength followed by the middle and coronal. CONCLUSION: The smart seal system was superior to all other sealers and displayed a good bond to dentin.

Scanning Electron Microscopy Analysis of the Intratubular Radicular Dentin Penetration of Calcium Hydroxide, Triple Antibiotic Paste, and Nitrofurantoin.

The aim of this study is to assess and analyze the intratubular penetration of the intracanal medications nitrofurantoin (Nit), triple antibiotic paste (TAP), and calcium hydroxide (CH). Sixty freshly extracted single-rooted teeth were acquired and decoronated to a standard length of 15 mm. To prepare specimens up to size F3, rotary ProTaper instrumentation was employed. The prepared teeth were divided into three groups, each of which received one of the tested intracanal medicaments: Group I (calcium hydroxide), Group II (triple antibiotic paste), and Group III (nitrofurantoin). Using a size #30 Lentulo spiral, a freshly prepared therapeutic paste was placed into the canals, and the intracanal medicaments were allowed to set in the incubator at 100% humidity. The samples were subsequently sliced perpendicularly to their long axis using a precision saw and assessed under a scanning electron microscope to assess the depth of penetration of intracanal medicaments at the coronal, middle, and apical portions of the root canal dentin. The data were analyzed using one-way ANOVA and Tukey's post hoc test. The statistical analysis revealed a significant difference between the experimental groups in the quantity and depth of sealer penetration (p < 0.05). In particular, as compared to the Nit group, both the CH and TAP groups had significantly smaller penetration areas (p < 0.05). In conclusion, this ongoing investigation indicates that nitrofurantoin penetrated dentinal tubules better than calcium hydroxide or triple antibiotic paste.

Pushout Bond Strength of Root Fillings after Irrigation of Root Canals Utilizing Sodium Hypochlorite, Chlorhexidine, and Homeopathic Mother Tincture (Arnica Montana).

The pushout bond strength of root fillings at radicular dentin was investigated employing NaOCl, CHX, and homoeopathic mother tincture (Arnica montana) as an irrigant. Sixty human permanent single-rooted extracted teeth were decoronated. The root canals were instrumented using Pro taper universal rotary system (Dentsply Tulsa Dental; Tulsa, Oklahoma) and were prepared up to F3 apical size. The roots were then randomly divided into three groups according to irrigation solution (n = 20) according to the final irrigation regimen: Group I: 3 mL 5.25% NaOCl followed by 3 mL Saline (control); Group II: 3 mL Arnica montana (10%, w/v) followed by 3 mL Saline; Group III: 3 mL CHX followed by 3 mL Saline. The canals were dried using paper points. The canals were coated with AH Plus sealer (Dentsply DeTey, Konstaz, Germany) with the aid of a Lentulo spiral (Dentsply DeTey, Konstaz, Germany) and obturated with #F3 gutta-percha. Each root was then horizontally sliced into three slices, labelled coronal, middle, and apical, each measuring 2 mm thick. Furthermore, at a crosshead speed of 2 mm/min, the test was carried out using the universal testing apparatus. The 5.25% NaOCl significantly decreased the bond strength of AH Plus to dentin. Both CHX and Arnica montana were capable of reversing the compromised pushout of AH Plus to NaOCl-treated dentin. After using NaOCl as an irrigant, the danger of diminished binding capacity of AH Plus to root canal walls arises. Final irrigation with Arnica montana and CHX reduces this risk.

Remineralization potential of fluoride, amorphous calcium phosphate-casein phosphopeptide, and combination of hydroxylapatite and fluoride on enamel lesions: An in vitro comparative evaluation.

AIM: The purpose of this study was to evaluate and compare remineralization potential of fluoride, amorphous calcium phosphate-casein phosphopeptide (ACP-CPP), and combination of hydroxyapatite (HAP) and fluoride on enamel lesions. MATERIALS AND METHODOLOGY: Ten intact caries-free human premolars were selected. The coronal portion of each tooth was sectioned into four parts to make four enamel blocks. The baseline surface microhardness (SMH) was measured for all the enamel specimens using Vickers microhardness testing machine. The artificial carious lesion was created by immersing the specimens in demineralizing solution for 3 consecutive days at 35° The SMH of each specimen was evaluated. All the four enamel sections of each tooth were subjected to various surface treatments, i.e., Group A - Fluoride varnish, Group B - ACP-CPP, Group C - Combination of HAP and fluoride (Clinpro), and Group D - Control group; no surface treatment. A carious progress test (pH cycle) was carried out which consisted of alternative demineralization (3 h) and remineralization using artificial saliva (21 h.) for 5 consecutive days. After pH cycling, SMH readings of each specimen were again assessed to evaluate remineralization potential of each surface treatment agent. RESULTS: Data obtained were statistically analyzed using one-way ANOVA followed by Tukey-Kramer multiple comparison test which was applied to detect significant differences between different surface treatments at different phases of studies. CONCLUSION: Fluoride varnish shows higher remineralization potential of early carious lesion compare to ACP-CPP and Clinpro.

Maxillary first molar with seven root canals diagnosed with cone-beam computed tomography scanning.

Nonsurgical endodontic therapy of a right maxillary first molar with three roots and seven root canals. This unusual morphology was diagnosed using a dental operating microscope (DOM) and confirmed with the help of cone-beam computed tomography (CBCT) images. CBCT axial images showed that both the palatal and distobuccal root have a Vertucci type II canal pattern, whereas the mesiobuccal root showed a Sert and Bayirli type XVIII canal configuration. The use of a DOM and CBCT imaging in endodontically challenging cases can facilitate a better understanding of the complex root canal anatomy, which ultimately enables the clinician to explore the root canal system and clean, shape, and obturate it more efficiently.

Comparison of shear bond strength of composite resin to enamel surface with laser etching versus acid etching: An in vitro evaluation.

INTRODUCTION: The aim of the study is in vitro evaluation of the shear bond strength of composite resin bonded to enamel which is pretreated using acid etchant and Er,Cr:Ysgg. MATERIALS AND METHODS: 40 extracted human teeth were divided in two groups of 20 each (Groups A and B). In Group A, prepared surface of enamel was etched using 37% phosphoric acid (Scotchbond, 3M). In Group B, enamel was surface treated by a an Er, Cr: YSGG laser system (Waterlase MD, Biolase Technology Inc., San Clemente, CA, USA) operating at a wavelength of 2,780 nm and having a pulse duration of 140-200 microsecond with a repetition rate of 20 Hz and 40 Hz. Bonding agent ((Scotchbond Multipurpose, 3M) was applied over the test areas on 20 samples of Groups A and B each, and light cured. Composite resin (Ceram X duo Nanoceramic restorative, Densply) was applied onto the test areas as a 3 × 3 mm diameter bid, and light cured. The samples were tested for shear bond strength. RESULTS: Mean shear bond strength for acid-etched enamel (26.41 ± 0.66MPa, range 25.155 to 27.150 MPa) was significantly higher (P < 0.01) than for laser-etched enamel (16.23 ± 0.71MPa, range 15.233 to 17.334 MPa). CONCLUSIONS: For enamel surface, mean shear bond strength of bonded composite obtained after laser etching were significantly lower than those obtained after acid etching.

Evaluation of Forces Generated on Three Different Rotary File Systems in Apical Third of Root Canal using Finite Element Analysis.

AIM: AIM of the study is to evaluate the distribution of forces on the instrument in the apical 3rd of curved canal with three Nickel Titanium rotary systems. METHODOLOGY: Three brands of instruments (ProTaper Universal; DENTSPLY Maillefer, RevoS; MicroMega and Hyflex; Coltene-Whaledent, Allstetten, Switzerland) were scanned with the Laser assisted computerized scanner to produce a real-size, 3-dimensional (3-D) model for each. The stresses on the instrument during simulated shaping of a root canal were analyzed numerically by using a 3-D finite element package, taking into account the nonlinear mechanical behavior of the nickel-titanium material. RESULTS: RevoS shows lowest values for force generation in the apical 3rd of canal as compared to Protaper which shows highest values, while Hyflex shows intermediate values for forces. CONCLUSION: With FE simulation of root canal shaping by 3 files, it was observed that different instrument designs would experience unequal degree of force generation in canal, as well as reaction torque from the root canal wall.