Diameter Variability of Rotary Files and Their Corresponding Gutta-Percha Cones Using Laser Scan Micrometre

Introduction: Manufacturers offer gutta-percha (GP) cones matched with different sizes of endodontic files as an attempt to simplify the obturation process and create a tight seal in the canal. The purpose of this study was to evaluate whether intra-manufacture GP diameters matched the diameters of their corresponding files at different levels using laser micrometre. Methods and Materials: Twenty files and corresponding GP master cones of Reciproc R40 (40/0.06) (VDW, Munich, Germany), WaveOne Large (40/0.08) (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper F3 (30/0.09) (Dentsply Maillefer, Ballaigues, Switzerland), and Mtwo 40/0.06 (VDW, Munich, Germany) were examined using laser micrometre (LSM 6000 by Mitutoyo, Japan) with accuracy of 1 nm to establish their actual diameter at D0, D1, D3 and D6. The data was analysed using the independent t-test. The differences were considered at 0.05. Results: The diameter of GP master cones was significantly larger than that of the corresponding files at all levels in all brands. ProTaper GP diameter was closest to the file diameter at D1 (GP=0.35, File=0.35 mm), and D3 (GP=0.48, File=0.49). Conclusion: Within the same manufacturer, GP cone diameters do not match the diameters of their corresponding files. Clinicians are advised to use a GP gauge to cut the tip so as to appropriate the diameter from a smaller sized GP cone.Keywords: Diameter; Gutta-Percha; Root Canal; Rotary File; Size 

The Intra-Manufacture Diameter Variability of Rotary Files and Their Corresponding Gutta-Percha Cones Using Laser Scan Micrometer

Introduction: As an attempt to simplify the obturation process and create a tight seal, manufacturers offer gutta-percha (GP) cones matching different sizes of endodontic files. The purpose of this study was to evaluate whether intra-manufacture GP diameters matched the diameters of their corresponding files at different horizontal levels of the canal. Methods and Materials: Twenty files and corresponding GP master cones of Reciproc R 40/0.08 (VDW, Munich, Germany), WaveOne Large (40/0.08) (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper F3 (30/0.09) (Dentsply Maillefer, Ballaigues, Switzerland), and Mtwo (40/0.06) (VDW, Munich, Germany) were examined using laser micrometer (LSM 6000 by Mitutoyo, Japan) with accuracy of 1 nm to establish their actual diameter at D0, D1, D3 and D6. Data were analysed using the independent t-test. The differences were considered as significant for P<0.05. Results: The diameter of GP master cones was significantly larger than the corresponding files at all levels with all the above brands. ProTaper GP diameter were closest to the file diameter at D1 (GP=0.35, File=0.35 mm), and D3 (GP=0.48, file=0.49). Conclusion: This in vitro study showed that within the same manufacturer GP cone diameters do not match the diameters of their corresponding files.Keywords: Diameter; Gutta-percha Cone; Laser Scan Micrometer; Rotary File; Tape

Management of merged external/internal root resorption using CEM cement: a case report

Chronic pulpal inflammation and infection are the main predisposing factors for internal and external root resorption (IRR & ERR); however, merging of IRR and ERR is a rare lesion which rigorously alters the anatomy of root canals. This study reports a case of merged IRR and ERR in an asymptomatic maxillary left central incisor in a 33-year old Caucasian woman that was managed by one-visit root canal therapy (RCT) using calcium-enriched mixture (CEM) cement. Radiographic examination showed a short root with under-filled root canal obturation associated with ERR/IRR and an apical lesion. After thorough chemo-mechanical preparation, the root canal was obturated with CEM cement; one week later, the access cavity was permanently restored. Clinical/radiographic examinations at 1-year follow-up revealed uneventful healing, reestablishment of lamina dura and stabilization of the resorptive defects. The treatment outcome demonstrates that one-visit RCT using CEM cement may be a viable treatment option in cases with merged external/internal root resorption. Further clinical trials with a larger number of cases are suggested to document a higher level of evidenc

A novel and facile synthesis of calcium silicate nanoparticles as a base for root canal cement/sealer under constant potential:Compared to chemical synthesis

Among inorganic biomaterials, which recently have received great attention in regenerative medicine, calcium silicate-based cements are bioactive materials that are prepared based on a composition of calcium and silicate. This manuscript explores the synthesis of pure calcium silicate (CaSiO3) nanoparticles using two different methods: sol-gel synthesis and electrochemical synthesis. The goal is to compare the structural characteristics of the synthesized products. In the sol-gel method, CaSiO3 is prepared using tetraethyl orthosilicate (TEOS) and calcium nitrate tetrahydrate, while in the electrochemical method; CaSiO3 is synthesized under constant potential using the same materials. The resulting nanoparticles were characterized using various analytical techniques such as scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction analysis (XRD). Additionally, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed. The XRD analysis revealed crystal sizes of 21 nm and 39.94 nm for electrochemical and chemical synthesis, respectively, indicating the formation of wollastonite-type CaSiO3 in the electrochemical method. SEM analysis showed average particle sizes of 62.44 nm and 119 nm for electrochemical and chemical synthesis, respectively. The results demonstrate that the proposed electrochemical method offers a simple, rapid, inexpensive, and high-purity approach for the synthesis of CaSiO3, which can serve as an alternative to chemical methods. The findings of this study contribute to the development of biomaterials for dental and medical applications.</p

Shear bond strength of composite resins to lithium disilicate ceramics using universal bonding and different methods of surface preparation

Background: Porcelain fracture or chipping is one of the limitations of all ceramic restorations. This study investigated the shear bond strength (SBS) of composite resins to lithium disilicate ceramics using universal bondings and different methods of surface preparation. Materials and Methods: In this experimental study, 72 specimens of e.max computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic blocks were divided into six groups of 12 according to surface treatment: Group I-Hydrofluoric (HF) acid etching + All-Bond Universal bonding (ABU), Group II-Bur roughening (BR) + HF + ABU, Group III-BR + HF + Bis-Silane (Si) + ABU, Group IV-Sandblasting (SB) + ABU, Group V-SB + HF + ABU, Group VI-SB + HF + Si + ABU. After bonding of composite resin to the prepared ceramic surface and storage of samples in distilled water for 24 h, SBS test was done using the universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed using the analysis of variance and Tukey's post hoc test (α = 0.05). Results: The mean values of SBS in six studied groups were 6.65 ± 2.78 MPa, 8.56 ± 2.69 MPa, 8.49 ± 2.14 MPa, 3.13 ± 1.66 MPa, 7.94 ± 2.4 MPa, and 10.04 ± 2.47 MPa, respectively. The mean values of SBS were significantly different (P < 0.001). The highest value of SBS was observed in Group VI and the lowest in Group IV. Conclusion: Ceramic sandblasting followed by HF etching, Bis Si, and ABU resulted in a higher SBS of composite resins to lithium disilicate ceramics

Marginal adaptation of zirconia complete-coverage fixed dental restorations made from digital scans or conventional impressions: A systematic review and meta-analysis

Statement of problem: Intraoral scanners have been increasingly used in recent years. However, the accuracy of digital scans as it affects marginal adaptation is unclear. Purpose: The purpose of this systematic review and meta-analysis was to compare the marginal adaptation of single-unit zirconia crowns fabricated with digital scans or with conventional impressions. Material and methods: The electronic databases PubMed (MEDLINE), Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science (ISI), Scopus, and EMBASE were searched and complemented by a manual search. Risks of bias were assessed by using a modified methodological index for nonrandomized studies (MINORS). Mean ±standard deviation (SD) values of marginal accuracy of studies were extracted for both methods. Mean marginal difference and 95% confidence interval (CI) were calculated to evaluate the marginal accuracy of each method. Pooled data were statistically analyzed by using a random-effect model. Results: Seventeen studies were used to perform the meta-analysis. Subgroup analysis was performed based on intraoral scanners. Standardized mean marginal difference and 95% CI of each subgroup were as follows: Lava: -0.85 μm (95% CI: -1.67, -0.03) (P=.043); CEREC: -1.32 μm (95% CI: -2.06, -0.59) (P<.001); iTero: -0.44 μm (95% CI: -1.35, 0.47) (P=.338); TRIOS: -1.26 μm (95% CI: -2.02, -0.51) (P=.001); unknown scanner: -0.21 μm (95% CI: -1.14, 0.72); all studies: -0.89 μm (95% CI: -1.24, -0.54) (P<.001). Conclusions: Digital scanning of prepared teeth for single-unit zirconia restorations resulted in better marginal accuracy than conventional techniques using elastomeric impression materials