Post-Space Treatment Influences the Bond Strength In Endodontically Treated Teeth: A Systematic Review and Meta-Analysis of In Vitro Studies.

OBJECTIVES: This systematic review of in vitro studies investigated the influence of the post-space treatment used to remove the smear layer on the bond strength of the post to root canal dentin. METHODS AND MATERIALS: In vitro studies included in this study were identified from PubMed/MEDLINE, Lilacs, and Scopus databases up until March 2019, without limits on publication year or language. Two reviewers independently selected the studies based on the inclusion and exclusion criteria, extracted the data, and evaluated the risk of bias of all studies. A random effects model was used for pairwise meta-analyses (control vs. post-space preparation groups) at a significance level of p<0.05. RESULTS: Of the 2,832 potentially eligible studies, 453 studies were selected for full-text analysis, and 75 were included in this systematic review. Only one study was considered to have a low risk of bias. Overall, post-space treatment significantly improves the bond strength to root canal dentin (p<0.00001). CONCLUSION: Post-space treatment has a positive influence on the bond strength of the post to root canal dentin. In this review, the post-space treatments that improve the adhesive resistance of the post were ethanol, sodium hypochlorite, and ethylene diamine tetra-acetic acid (NaOCl + EDTA), NaOCl + EDTA + ultrasound, erbium-doped yttrium aluminium garnet laser (Er:YAG laser), neodymium-doped yttrium aluminium garnet laser (Nd:YAG laser), and diode laser.

Effect of Different Surface Treatments of Resin Relined Fiber Posts Cemented With Self-adhesive Resin Cement on Push-out and Microtensile Bond Strength Tests.

CLINICAL RELEVANCE: When luting relined fiber posts with self-adhesive cement, the surface treatment of the posts influences the adhesion of the fiber posts to root dentin. SUMMARY: This study evaluated the effect of surface treatment and silanization of resin composite on the bond strength of relined fiber posts cemented with self-adhesive resin cement. Push-out and microtensile bond strength (MTBS) tests were performed in this study. The endodontic treatment of 80 single-rooted bovine teeth was first performed in the push- out test segment, followed by weakening the intracanal walls by diamond bur. Then, the glass fiber posts were adapted with resin composite to fill the root canals, followed by photoactivation and resin surface conditioning according to four different experimental conditions: no conditioning as control, 10% hydrofluoric acid, 35% hydrogen peroxide, or air abrasion with alumina particle (all groups were subdivided into "with silanization" or "without silanization," thus totaling eight experimental groups). Self-adhesive resin cement was used for the post cementation. Four slices per tooth were obtained for the push-out tests. Next, 160 blocks of resin composite were first produced for the MTBS tests; their bonding surfaces were conditioned (as mentioned, ie, eight treatments), and they were cemented to each other. The 80 sets (n=10/treatment) were then cut into microbars (16/set): eight were immediately tested, while the other eight were thermocycled (12,000×) and stored (120 days) before MTBS. Failure modes and topographic analyses were performed after treatments. There was no statistically significant difference for the push-out results. In MTBS, surface treatment and silanization had a significant effect (p<0.001). Aging decreased bond strength for all groups. Considering the aged groups, air abrasion promoted the highest values and silanization improved bond strength for all treatments except air abrasion. The alumina particle air abrasion of the relining resin composite promoted the highest bond strengths when luting with self-adhesive resin cement.

Effect of Ferrule Thickness on Fracture Resistance of Teeth Restored With a Glass Fiber Post or Cast Post.

PURPOSE: To investigate the influence of ferrule thickness on fracture resistance after mechanical cycling of teeth restored with different intracanal posts. METHODS AND MATERIALS: One hundred twenty bovine incisor teeth were randomized into six study groups, based on the intracanal post used (fiber post or cast post and core) and the presence and thickness of a ferrule (without ferrule, presence of 0.5-mm or 1-mm-thick ferrule, retaining unaltered 2-mm ferrule height). The root posts and the metal crowns were cemented using an adhesive cement. The samples were subjected to mechanical cycling (at 37°C, 45°, 130 N, 2.2 Hz, and 2 × 106 pulses). Afterward, they were subjected to a fracture load test at a speed of 0.5 mm/min and on a 45° slope until failure occurred. The failures were classified as favorable or unfavorable. The fracture resistance data were analyzed with two-way analysis of variance and Tukey test. The chi-square test was used to analyze the pattern of failure. RESULTS: When considering the cast post and core, the 1-mm ferrule thickness group presented a higher resistance to fracture than did the group in which a ferrule was not used (p=0.001). When using a glass fiber post, the groups showed no differences in fracture resistance. Overall, 96.7% of the specimens survived the mechanical cycling. Of the fractures, 58.6% of the fractures were unfavorable, while 41.6% were favorable. CONCLUSIONS: A thicker ferrule statistically increased the fracture resistance only for cast post and core when it was at least 1 mm thick, despite causing more unfavorable failures. Thus, ferrule thickness should be considered when choosing different intracanal posts, to reduce the occurrence of unfavorable failures. In the absence of a ferrule, the use of a cast post and core presents more favorable failures, and in the presence of a 1-mm-thick ferrule, the use of a glass fiber post seems to be the best clinical decision.

A systematic review of different substance injection and dry needling for treatment of temporomandibular myofascial pain.

Temporomandibular myofascial pain presents a major challenge in the diagnosis of temporomandibular disorders (TMD). Due to the characteristics of this condition, intramuscular injection procedures are often needed for adequate control of symptoms and treatment. Thus, the aim of this systematic review was to evaluate the effectiveness of dry needling and injection with different substances in temporomandibular myofascial pain. Electronic databases PubMed, EMBASE, CENTRAL/Cochrane, Lilacs, Scopus, Web of Science and CAPES Catalog of Dissertations and Theses were searched for randomized clinical trials until January 2018. Manual search was performed in relevant journals and in the references/citations of the included studies. The selection of studies was carried out by two independent reviewers according to eligibility criteria. From 7128 eligible studies, 137 were selected for full-text analysis and 18 were included. Due to the heterogeneity of the primary studies it was not possible to perform a meta-analysis. The narrative analysis of the results showed that most of the studies had methodological limitations and biases that compromised the quality of the findings. Dry needling and local anaesthesic injections seem promising, but there is a need to conduct further randomized clinical trials, with larger samples and longer follow-up times, to evaluate the real effectiveness of the technique and evaluated substances.

Effect of Intracanal Irrigants on Bond Strength of Fiber Posts Cemented With a Self-adhesive Resin Cement.

OBJECTIVE: The aim of this study was to evaluate the effect of five intracanal irrigants on bond strength of fiber posts cemented with newer self-adhesive resin cement. METHODS: A total of 60 extracted, single-rooted human premolars, sectioned at 14 mm, were prepared with the ProTaper Universal system with a size F3 instrument and filled with an F3 master cone and AH Plus. The root canal filling was partially removed, leaving 4 mm of apical gutta-percha. Specimens were randomly assigned to five groups (n=12), according to the solution used for dentin surface treatment before fiber post cementation, as follows: EDTA 17% (EDTA); QMix (QM); SmearClear (SC); 2.5% sodium hypochlorite (NaOCl), and 0.9% saline solution (SS). Ultrasonic activation was performed (three times, 20 seconds each), and root canals were dried with paper points. Fiber posts were cemented with RelyX U200. In one specimen per group, rhodamine B dye was mixed with RelyX U200 to provide adequate fluorescence for confocal laser scanning microscopy (CLSM) assessment. Specimens were transversally sectioned and three slices were obtained, one for each root third. Next, a push-out test was performed. A stereomicroscope and CLSM were used to analyze the failure modes and to illustrate the pattern of infiltration of RelyX U200 into dentinal tubules, respectively. Bond strength means were calculated, and analysis of variance and Bonferroni tests were used for statistical analysis. RESULTS: SS showed the highest mean bond strength values (11.5±5.3), superior to QM (5.1±3.1) and SC (5.1±3.3). NaOCl presented intermediary bond strength values (9.7±5.0), similar to EDTA (7.7±2.9) and SS. QM and SC showed the lowest mean bond strength (p<0.05). Adhesive failures between cement/dentin were predominant (53.9%). CONCLUSION: SS and NaOCl associated with ultrasonic activation seem to be adequate solutions for root canal cleaning before fiber post cementation with self-adhesive resin cement, whereas chelating solutions, such as EDTA, QM, and SC, cause a decrease in bond strength.