Shaping ability of Procodile and R6 Reziflow nickel-titanium reciprocating instruments in curved mesial root canals of mandibular molars: A MicroCT study.

To compare the shaping ability of Procodile and R6 Reziflow instruments used in reciprocating motion in severely curved root canals, assessed with micro-computed tomography (µCT). Fourteen extracted human mandibular first molars were randomly assigned to two instrumentation techniques (n = 14 mesial root canals): Procodile or R6 Reziflow. For both groups, root canals were prepared to the working length up to a size 25, .06 taper. Molars were virtually divided into apical, middle and coronal thirds and µCT was used to scan all samples pre- and post-root canal. Canal transportation, centring ability, volume, surface area and unprepared area were evaluated. Geometrical parameter changes were compared with preoperative values (one-way analyses of variance and Tukey multiple comparison post-hoc test) between groups and Student t-test within groups (α = 0.05) Significantly less transportation was observed associated with the Procodile technique in the molar's coronal third compared to the R6 Reziflow technique (p < .05). No significant differences in root canal centring ability, volume, surface area and unprepared area were observed. Procodile showed a lower percentage increase of surface area compared to R6 Reziflow (p < .05). The Procodile and R6 Reziflow techniques applied to first molar root canal performed similarly except for the less transportation observed in the coronal third using Procodile. RESEARCH HIGHLIGHTS: MicroCT analysis of canal geometry before and after instrumentation revealed that Procodile and R6 Reziflow showed a similar shaping ability to shape curved root canals without substantially modifications of the original tooth anatomy.

Effects of Surface Treatments of Glass Fiber-Reinforced Post on Bond Strength to Root Dentine: A Systematic Review.

The objective of this systematic review was to determine the influence of surface treatment of glass fiber posts on bond strength to dentine. Laboratory studies were searched in MEDLINE, PubMed, Embase, PubMed Central, Scopus, and Web of Science search engine. All authors interdependently screened all identified articles for eligibility. The included studies were assessed for bias. Because of the considerable heterogeneity of the studies, a meta-analysis was not possible. Twelve articles were found eligible and included in the review. An assessment of the risk of bias in the included studies provided a result that classified the studies as low, medium, and high risk of bias. The available evidence indicated that the coronal region of the root canal bonded better to the glass fiber post than apical regions. Phosphoric acid, hydrogen peroxide, and silane application enhance post's retentiveness. In light of the current evidence, surface treatment strategies increase the bond strength of glass fiber post to dentine. However, recommendations for standardized testing methods and reporting of future clinical studies are required to maintain clinically relevant information and to understand the effects of various surface treatment of glass fiber post and their bond strength with dentine walls of the root canal.

Outcome of Root Canal Treatments Using a New Calcium Silicate Root Canal Sealer: A Non-Randomized Clinical Trial.

BACKGROUND: The aim of this study was to compare the success rate of root canal treatments undertaken using a calcium silicate root canal sealer in combination with a single cone with non-calcium silicate cement and warm vertical condensation. METHODS: 150 necrotic or pulpitic teeth were treated. (REC: 08/H0804/79). Following standardized root canal chemo-debridement. The canals were obturated using warm vertical condensation of gutta-percha and epoxy-based sealer (AH plus) or a calcium silicate sealer (BioRootTM RCS) with a single cone technique. Follow-up assessment was conducted at 12 months using Cone Beam Computed Tomography (CBCT). RESULTS: At 1-year recall, 104 teeth were assessed (51 AH plus, 53 BioRootTM RCS). The success rate using loose criteria for the CBCT images and PA radiographs was respectively 80% and 89% in the AH plus/warm vertical condensation group, 84% and 90% in the BioRootTM RCS/single cone group. There was no statistically significant difference between the two groups (Fisher exact test p value 0.6099 for the CBCT images). CONCLUSION: Within the limitations of this non-randomized trial, a calcium silicate cement in combination with single cone resulted in a similar proportion of successful cases compared to warm vertical condensation and epoxy-based sealer.

Reduction of an in vitro Intraradicular Multispecies Biofilm Using Two Rotary Instrumentation Sequences.

OBJECTIVE: The purpose of this research was to investigate the effect per se of two shaping and cleaning techniques on the reduction of an in vitro multispecies biofilm. MATERIALS AND METHODS: A total of 39 freshly extracted monoradicular teeth for periodontal reason were decoronated. Roots were sectioned longitudinally. After autoclaving, a specific stressed biofilm was grown on the root halves that were subsequently reassembled in a silicone index. Two treatments (n = 9 each)-RaCe (Schottlander; Letchworth Garden City, United Kingdom) and ProTaper Gold ( PTG; Dentsply Maillefer, Baillagues, Switzerland)-were tested; three noninstrumented samples served as a control group and three were rinsed with saline. Posttreatment samples were taken at three different levels of the root. Colony-forming units were counted after incubations. Additionally, three treatments (n = 5 each)-RaCe, PTG, and saline only-were evaluated under a confocal laser scanning microscope (CLSM). STATISTICAL ANALYSIS: Statistical analysis was conducted using Tukey's test and analysis of variance to evaluate the post-instrumentation bioburden. RESULTS: Both instrumentations were able to reduce the biofilm; however, differences were not present between them (p > 0.05). CLSM showed biofilm killing and disruption through mechanical shaping alone. CONCLUSIONS: Intraradicular biofilm is reduced with mechanical shaping. There was no difference between RaCe and PTG systems in biofilm reduction despite differences in design, file sequence, and rotational speed.

Micro-computed tomography evaluation of microleakage of Class II composite restorations: An in vitro study.

OBJECTIVE: The aim of this study is to investigate the microleakage attained with three resin-based material used to restore deep Class II cavities. A null hypothesis was chosen: there is no difference in microleakage among the tested materials. MATERIALS AND METHODS: A total of 30 Class II cavities were prepared in freshly extracted molars with the proximal mesial and distal margins located, respectively, 1.5 mm apically and 1.5 mm coronally to the cementum-enamel junction. Restorations were completed using a three-step enamel-dentin adhesive system "Etch and Rinse," margins were relocated using a micro-hybrid, preheated, or flowable composite and restorations were then completed using a conventional composite. All samples were coated with nail varnish with the exception of an area along the margins and apex was sealed using epoxide cement and then thermocycled (30-s dwell time, 5°C/55°C, 1000 cycles). A 50% ammoniac AgNO3 solution was used as tracer according to Tay's protocol. The microleakage analysis was performed using a microtomography system Sky-scan 1072 (SKYSCAN, Kartuizersweg 3B 2550, Konitch, Belgium). RESULTS: The mean microleakage of all the tested materials showed greater leakage in the cementum margins; flowable composite exhibit greater leakage among the groups. Significant differences (P < 5%) within groups in both enamel and dentin margins were present. None of the tested materials eliminated marginal microleakage. Preheated composite showed significantly lesser microleakage. CONCLUSION: Tested materials showed statistical differences in microleakage; thus, the null hypothesis has been rejected. Within the limitations of the present experimental procedure, it can be concluded that flowable resin composite should be avoided at the dentin/cementum margin.

Alternative practices of achieving anaesthesia for dental procedures: a review

Managing pain and anxiety in patients has always been an essential part of dentistry. To prevent pain, dentists administer local anaesthesia (LA) via a needle injection. Unfortunately, anxiety and fear that arise prior to and/or during injection remains a barrier for many children and adults from receiving dental treatment. There is a constant search for techniques to alleviate the invasive and painful nature of the needle injection. In recent years, researchers have developed alternative methods which enable dental anaesthesia to be less invasive and more patient-friendly. The aim of this review is to highlight the procedures and devices available which may replace the conventional needle-administered local anaesthesia. The most known alternative methods in providing anaesthesia in dentistry are: topical anaesthesia, electronic dental anaesthesia, jet-injectors, iontophoresis, and computerized control local anaesthesia delivery systems. Even though these procedures are well accepted by patients to date, it is the authors' opinion that the effectiveness practicality of such techniques in general dentistry is not without limitations.

Tooth loss in molars with and without furcation involvement - a systematic review and meta-analysis.

BACKGROUND: The aim of this study was to investigate risk of tooth loss in molars with furcation involvement (FI) based on initial diagnosis. MATERIALS AND METHODS: A systematic search of the literature was conducted in Ovid Medline, Embase, LILACS and Cochrane Library for longitudinal studies with at least 3 years follow-up including measures of FI and data on tooth loss. RESULTS: A total of 21 studies were included in the review, from an initial search of 1207 titles. The relative risk of tooth loss during maintenance therapy attributable to FI was 1.46 (95% CI = 0.99-2.15, p = 0.06) for studies up to 10 years and 2.21 (95% CI = 1.79-2.74, p < 0.0001) for studies with a follow-up of 10-15 years. A gradual increase in the risk of tooth loss was observed for molars with degree II and III FI. CONCLUSIONS: The presence of FI approximately doubles the risk of tooth loss for molars maintained in supportive periodontal therapy for up to 10-15 years. However, most molars, even with grade III FI respond well to periodontal therapy, suggesting that every effort should be made to maintain these teeth when possible. Long-term studies reporting patient-reported outcomes are needed to substantiate this conclusion.