Comparison of crack formation induced by ultrasonic tips and burs during root-end preparation: a systematic review and meta-analysis.

Introduction The main objective of root canal treatment is to achieve apical seal. Crack formation during root-end preparation promotes bacterial penetration, thereby leading to failure. This systematic review aims to examine the literature and summarise studies that compare the crack formation induced by ultrasonic tips and burs during root-end preparation.Methods This systematic review and meta-analysis were reported and conducted according to the PRISMA guidelines. The online databases PubMed, Scopus, and Google Scholar were used for data search. In vitro and ex vivo studies conducted up to March 2021 in the English language were included in the review. The risk of bias in the present study was assessed using a customised tool. A random-effects model was used for meta-analysis, χ² values and I² values were used to assess statistical heterogeneity. Meta-analysis was performed using RevMan software Version 5.4.Results A total of 317 records were found from all of the databases and one article was added following hand-searching. Twelve articles were included in the study after the application of the eligibility criteria of which ten articles were included for the meta-analysis. Nine studies showed a medium risk of bias while three studies showed a high risk of bias. The analysis of the crack formation showed a statistically significant difference between the ultrasonic tip and the bur (P = 0.0002). The odds ratio was 2.72 (1.60, 4.65) with a confidence interval of 95% suggesting higher odds of crack formation in the ultrasonic group.Conclusion This review concludes that ultrasonic root-end preparation resulted in higher crack formation than burs.

Comparative evaluation of shear bond strength of calcium silicate-based liners to resin-modified glass ionomer cement in resin composite restorations - a systematic review and meta-analysis.

Purpose The aim of this systematic review was to evaluate the difference in shear bond strength between calcium silicate-based liners to resin-modified glass ionomer cement (RMGIC) in resin composite restorations.Materials and methods The protocol was registered in PROSPERO following which primary research was carried out on Medline, Scopus and Cochrane library. To assess the risk of bias, a customised tool was used. Among the 194 records retrieved from the databases, only ten articles qualified for qualitative and quantitative synthesis after meeting all the requirements of the eligibility criteria. Covidence software was used to record the decisions. Studies published until 31 March 2021 were taken up for the review. The articles showed a low-to-moderate risk of bias. I2 test was used to check the percentage variation due to heterogeneity.Results RMGIC showed a higher shear bond strength value compared to the three calcium silicate liners MTA, Biodentine and TheraCal LC. However, TheraCal LC and MTA showed better bond strength than Biodentine. Cohesive failure was seen predominantly in liners followed by adhesive failure. RMGIC shows mixed mode of failure in some studies.Conclusions RMGIC is preferred over calcium silicate-based materials as the liner to be used under resin composite restorations. Among calcium silicate-based materials, TheraCal LC showed a better bond strength value. The mode of failure was predominantly cohesive in all the liner groups in majority.

Prevalence and severity of coronal and radicular caries among patients with type 2 diabetes mellitus: A cross sectional study.

Background: Studies among type 2 diabetes mellitus patients have reported total caries experience; however the severity and clinical consequences of untreated dental caries are often ignored. Methods: For this study, 150 well (I) and poorly controlled (II) diabetic participants were recruited. The spectrum of caries was evaluated using DMFT (Decayed, Missing and Filled Tooth) index, Dental Caries Severity Classification Scale, PUFA (Pulpal involvement, Ulceration, Fistula and Abscess) index, RCI (Root Caries Index) and the severity of radicular caries by Root Surface Caries Severity Index. Results: The prevalence of coronal and root caries was 90.7% and 23.3%, respectively. There was significant difference among caries experiences for D, M and DMFT. In group II, severity of coronal caries and mean rank of P, F, A and PUFA scores were higher, so were prevalence of root caries and severity of RD2, RD3 and RD4. HbA1c level had positive correlation with DMFT and PUFA scores (r = 0.458 and 0.522), so was the duration of diabetes with coronal caries, DMFT, PUFA score, root caries and RCI score (r = 0.235, 0.320, 0.273, 0.308 and 0.323). Conclusion: This is probably the first study to examine the severity of coronal caries, prevalence of untreated dental caries and severity of radicular caries in diabetic patients. Uncontrolled diabetes causes substantial increase in prevalence and severity of coronal and radicular caries.

COVID-19 Antibody Tests: An Overview.

Novel coronavirus (nCoV) first emerged in Hubei province of China in December 2019. The virus initially known as 2019-nCoV was renamed to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) by the International Committee on Taxonomy of Viruses. The associated disease is known as coronavirus disease 2019 (COVID-19). As the COVID-19 pandemic has unfolded, interest has grown in antibody testing as a way to measure how far the infection has spread and to identify individuals who may be immune. Molecular diagnostic tests like polymerase chain reaction are developed rapidly, however they are not able to fulfill all the requirements of an epidemic reaction. Hence, to complement molecular diagnostic tests, serology tests emerged as a vital aspect of the overall response by confirming the presence of antibodies during the early stage of the infection. Antibody tests help in assessing herd immunity, data about the ongoing phase of infection, identifying potential donors for convalescent plasma therapy, etc. This review currently focuses on giving an overview about the antibody tests in SARS-CoV-2 infections.

A Comparative Evaluation of Microleakage between Resin-Modified Glass Ionomer, Flowable Composite, and Cention-N in Class V Restorations: A Confocal Laser Scanning Microscope Study.

BACKGROUND: Microleakage is a concern while restoring cervical lesions. Many products have attempted to minimize the interfacial gap between the tooth and restoration, the main pathway of microleakage. AIMS AND OBJECTIVE: To compare and evaluate the microleakage in Class V cavity restored with nanohybrid flowable composite, Resin modified Glass Ionomer and Cention N. METHOD: Class V cavities were prepared on mandibular premolars on buccal surface with their occlusal margin placed in enamel and the gingival margin in dentin. The teeth were randomly assigned to three groups of 20 teeth each and restored with Flowable composite , Resin Modified GIC and Cention N. Samples were immersed in 0.5% Rhodamine dye, sectioned and microleakage measured using Confocal Laser Scanning Microscopy. Statistical analysis was done using Oneway ANOVA Bonferroni's test and Kruskal Waliis test. RESULTS: The average depth of penetration of dye and scoring of depth were noted. On comparing dye penetration values between groups, RMGIC is compared with Flowable composite and Cention N, statistically significant result was obtained suggesting lesser dye penetration in RMGIC group (P < 0.001) where other comparison did not. CONCLUSION: RMGIC showed significantly less microleakage compared to the other two restorative materials used in the study and enamel margin of all restorations showed lesser microleakage than dentin margin.

Comparative Evaluation of Fracture Resistance of Incisor Fragments Using Simple, Bevel, Internal Groove Preparation Designs and Reattached with Nanocomposites: An In Vitro Study.

AIM: The aim of this in vitro study was to evaluate the fracture resistance of anterior crown fragments using three different preparation designs and reattached using two different nanocomposites. MATERIALS AND METHODS: A total of 120 sound human permanent incisors were selected and divided into six groups. The teeth were sectioned and reattached using different preparatory designs and nanocomposites. Group A (simple reattachment with G-aenial Universal Flo), Group A2 (bevel preparation reattached with G-aenial Universal Flo), Group A3 (internal groove preparation reattached with G-aenial Universal Flo), Group B1 (simple reattachment with Polofil NHT Flow), Group B2 (bevel preparation reattached with Polofil NHT Flow), and Group B3 (internal groove preparation reattached with Polofil NHT Flow). The teeth were sectioned and reattached using different preparatory designs and nanocomposites. These teeth were then subjected to thermocycling, and fracture resistance of the reattached fragments was recorded using Instron machine. RESULTS: Group A3 showed the highest fracture resistance. The least fracture resistance was seen in Group B1. CONCLUSION: The fracture resistance of reattached incisor fragments depends mainly on the preparation design incorporated and also the material used to restore. Fragments where internal groove preparatory design was done and reattached with G-aenial Universal Flo, showed greater fracture resistance. Simple reattachment preparatory design showed the least fracture resistance, and hence must be avoided.

Comparative Evaluation of Microcrack Formation in Different Kinematics Using Rotary and Reciprocating File Systems: An In Vitro Study.

AIM AND OBJECTIVE: To compare r oot microcrack formation after r oot canal preparation using ProTaper Next in r otation or forward r eciprocation and Waveone gold in r everse r eciprocating motion. MATERIALS AND METHODS: Buccal r oots of 60 maxillary premolars with mature apices were selected, for different instrumentation techniques and divided into three groups. Coronal access was achieved and the canals were confirmed for apical patency. The canals were then instrumented using the following instrumentation techniques: ProTaper Next in r otation or forward r eciprocation or Waveone gold in r everse reciprocation. The tooth was then subjected to sectioning using a diamond saw under water cooling and then was visualized under the stereomicroscope for dentinal microcrack. RESULTS: The results showed that the maximum dentinal microcrack formed at apical 3 and 6 mm was in Waveone gold in reverse reciprocation followed by ProTaper Next in forward reciprocation and rotation. However, the p value was found to be not significant at 3 and 6 mm (p value-0.082 and 0.23). CONCLUSION: Nickle titanium rotary instruments tend to induce varied degrees of root dentinal damage during canal instrumentation. ProTaper Next files in rotation as well as forward reciprocation presented with minimal microcrack defects when compared with Waveone gold. CLINICAL SIGNIFICANCE: Root canal preparation, when performed by manual or engine-driven techniques, has shown to produce structural defects in the root dentin. One of the causes of failures in root canal treatment is because of fracture in the dentin that occurs due to these procedures. Though all the motion kinematics caused microcracks in this study, it was seen that rotational motion produced the least structural damage to the dentin.

Effect of Instrumentation Techniques and Kinematics on Apical Extrusion of Debris: An In Vitro Study.

AIM: To evaluate the effect of instrumentation kinematics on debris extrusion by comparing the amount of apically extruded debris after canal preparation using ProTaper next in continuous rotation as well as forward reciprocating motion and WaveOne gold in reverse reciprocating motion. MATERIALS AND METHODS: We randomly divided ninety buccal roots of maxillary bicuspids with fully formed apices into three groups. After achieving the coronal access, the patency of the root canals was established with a size 10 K file. The canals were then instrumented using ProTaper next in continuous rotation or in a forward reciprocating motion and WaveOne gold in reverse reciprocating motion. Eppendorf tubes were used to collect the debris extruded through the apical foramen. The tubes were placed in a -80° freezer for 8 hours and then in a lyophilizer for 24 hours. The quantity of the apically extruded debris was assessed by subtracting the weights of Eppendorf tubes before and after instrumentation. The analysis was done using a one-way ANOVA test and the Bonferroni test to compare the groups. RESULTS: The mean weight of extruded debris with WaveOne gold in reverse reciprocation was significantly lower than ProTaper next in forward reciprocation and ProTaper next in continuous rotation (p value = <0.001). CONCLUSION: WaveOne gold in reverse reciprocation was associated with a significantly lower amount of apical extrusion of debris than ProTaper next rotary files in forward reciprocation and continuous rotation. CLINICAL SIGNIFICANCE: According to the results of this study, reciprocating instrumentation technique was associated with a less amount of debris extrusion compared to continuous rotation.