A Novel Polyurethane Expandable Root Canal Sealer

Introduction: Endodontic sealers play a vital role in the obturation of root canal space. The aim of this study was to evaluate the utility of a recently developed polyurethane expandable sealer (PES), along with its cytotoxicity and dimensional changes. Methods: L929 fibroblasts and an cell viability assay (MTS assay) were used to determine the cytotoxicity of dental sealers (AH Plus [Dentsply Maillefer, Ballaigues, Switzerland], Sure-Seal Root [Sure Dent Corporation, Gyeonggi-do, South Korea], and the PES) at 24, 48, 72, and 96 hours. An advanced choroidal neovascularization model was used to assess the effect of these sealers on angiogenesis. Thirty-six extracted single-rooted human teeth were prepared and randomly divided into 3 groups (n = 12). Obturation was performed with gutta-percha and a sealer using lateral compaction as follows: group 1, AH Plus; group 2, Sure-Seal; and group 3, PES. The average depth of sealer penetration into dentinal tubules was measured with a scanning electron microscope. Data were analyzed using 1-way analysis of variance and post hoc Tukey tests (level of significance, P \u3c .05). Results: The values of MTS, choroidal neovascularization, and the penetration depth of PES were significantly higher than in other experimental groups (P \u3c .05). The lowest values were noted in specimens of AH Plus, whereas the highest were detected in the PES group. Conclusions: PES showed promising results in terms of biocompatibility and dentinal tubule adaptation and penetration

A new reliable alternate method to an intraoral scanner (in-vitro study)

Objective: To propose a method to develop 3-dimensional (3D) models of regular and orthodontic typodonts by using their 2-dimensional (2D) images, as an alternate method to 3D scanners. Materials and methods: To propose a method to develop 3-dimensional (3D) models of regular and orthodontic typodonts by using their 2-dimensional (2D) images, as an alternate method to 3D scanners. Matierals and methods: The mandibles of two typodonts, regular occlusion and malocclusion, were scanned by using a 3D scanner to generate their models. Captured scans were used to determine the accuracy of the existing method. One hundred images of each mandible were made by using a smartphone from various angles five times to create required and generate 3D models through the software. The percentage overlap of the hard tissues of the scans and the models superimposed within the group (repeatability test), and with each other (accuracy test) gathered the proposed method\u27s accuracy and precision. The data were analyzed by using the Student\u27s t-test. Results: Ten scans and ten models were overlapped among themselves and each other and evaluated. Repeatability test; significant overlap in scans for both mandibles (regular and maloccluded), and their 3D model\u27s counterparts (P \u3c 0.05, CI 95%). Accuracy tests; significant overlap between both methods for both mandibles (P \u3c 0.05, CI 95%). Conclusion: The 2D images were successfully used to model the teeth (both regular and maloccluded) non-invasively. The proposed method showed high reproducibility as well as accuracy when compared to a commercially available 3D scanner. Clinical significance: The 3D models for both regular teeth and teeth with malocclusions were modeled by using 2D images taken with a smartphone by using the novel method which was both reproducible and accurate

Effect of Diabetes on Rotary Instrumentation of Dentin

Introduction: Diabetes mellitus (DM) may affect the physical and mechanical properties of dentin, which could potentially have an impact on root canal procedures. This study aimed to compare the amount of dentin removed by an endodontic rotary file, comparing dentin from diabetic patients with dentin from control patients under laboratory conditions. Methods: The amount of dentin removed was tested using new F3 ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) files applied against the surface of prepared dentin discs for 3 different groups: diabetic type 1 (D1), diabetic type 2 (D2), and nondiabetic (normal). The dentin removed was determined by measuring the depth of penetration of the file using a digital caliper and by measuring the weight loss. Data were analyzed using Kolmogorov-Smirnov, analysis of variance, post hoc Tukey, and Pearson correlation tests (P \u3c .05). Results: Significantly more dentin was removed, and the penetration of the F3 instrument was significantly higher (P \u3c .05) in DM specimens. The statistical analysis revealed significant differences between the D1, D2, and normal groups (P \u3c .05) for the weight loss of the specimen as well as the penetration depth at point B (P \u3c .05). Both the weight loss and depth of penetration showed a very high positive correlation (P \u3c .05). Conclusions: The dentin of patients suffering from both D1 and D2 exhibited an increased amount of dentin removed compared with the nondiabetic dentin specimens. This can be observed by the increased penetration of the rotary instruments into dentin. Under certain circumstances, this may impact instrumentation, increasing procedural accidents and leading to subsequent weakening of root canal–treated teeth in diabetic patients

The effect of diabetes on Fracture Resistance of Teeth: An in vitro study

The root fracture resistance (RFR) of premolars extracted from diabetic patients and the effect of biomaterials: white mineral trioxide aggregate (WMTA) and WMTA+Na2HPO4 as an additive, on enhancing RFR were evaluated. Diabetic and non-diabetic teeth were divided into 4 subgroups (n = 5): root canals were obturated with WMTA, WMTA+Na2HPO4, gutta-percha and one unfilled (control). A plunger (1 mm diameter) applied a downward compressive load with crosshead speed of 1 mm min−1 on the specimens mounted on resin blocks, and the ultimate force to fracture was measured. The mean RFR values of diabetic specimens were significantly lower. The lowest and highest means of RFR were recorded in the control and WMTA, in normal group and the control and WMTA+Na2HPO4 in the diabetic group, respectively. The RFR in diabetic patients was significantly lower, indicating their higher susceptibility to fracture under vertical forces. The use of WMTA (with or without Na2HPO4) for obturation enhances the RFR

Effect of Diabetes on Rotary Instrumentation of Dentin

Introduction: Diabetes mellitus (DM) may affect the physical and mechanical properties of dentin, which could potentially have an impact on root canal procedures. This study aimed to compare the amount of dentin removed by an endodontic rotary file, comparing dentin from diabetic patients with dentin from control patients under laboratory conditions. Methods: The amount of dentin removed was tested using new F3 ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) files applied against the surface of prepared dentin discs for 3 different groups: diabetic type 1 (D1), diabetic type 2 (D2), and nondiabetic (normal). The dentin removed was determined by measuring the depth of penetration of the file using a digital caliper and by measuring the weight loss. Data were analyzed using Kolmogorov-Smirnov, analysis of variance, post hoc Tukey, and Pearson correlation tests (P \u3c .05). Results: Significantly more dentin was removed, and the penetration of the F3 instrument was significantly higher (P \u3c .05) in DM specimens. The statistical analysis revealed significant differences between the D1, D2, and normal groups (P \u3c .05) for the weight loss of the specimen as well as the penetration depth at point B (P \u3c .05). Both the weight loss and depth of penetration showed a very high positive correlation (P \u3c .05). Conclusions: The dentin of patients suffering from both D1 and D2 exhibited an increased amount of dentin removed compared with the nondiabetic dentin specimens. This can be observed by the increased penetration of the rotary instruments into dentin. Under certain circumstances, this may impact instrumentation, increasing procedural accidents and leading to subsequent weakening of root canal–treated teeth in diabetic patients