Search Results (11)

Objective: This study aims to evaluate the stress distribution on endodontically treated anterior teeth restored using different restorative materials and different post lengths versus endocrowns employing finite element analysis (FEA). Methods: An extracted human central incisor tooth with a fully formed apex was scanned using high-resolution cone beam computed tomography (CBCT) to generate 3D finite element models. Six models of restorations of badly destructed central incisor were grouped according to the type of ceramic material and post length versus endocrown restorations. Group V-L: Vita Enamic, long post (10 mm intra-radicular), Group C-L: Celtra Duo, long post (10 mm intra-radicular), Group V-Sh: Vita Enamic, short post (3 mm intra-radicular), Group C-Sh: Celtra Duo, short post (3 mm intra-radicular), Group V-E: Vita Enamic endocrown (3 mm intra-radicular), and Group C-E: Celtra Duo endocrown (3 mm intra-radicular). A static load of 200 N was applied to the palatal surface at a 45 degree angle to the tooth’s long axis. The maximum equivalent von Mises stress and maximum principal stress were analyzed at four locations: the finish line, coronal third of the root (12 mm from the apex), middle third of the root (8 mm from the apex), and apical third of the root (4 mm from the apex). Results: Group C-L exhibited the highest maximum VM stress and PS at the finish line, in addition to the highest maximum VM stress and PS at the root apical third, while group C-Sh reported the least maximum VM stress at the root apical third among the groups. All Celtra Duo groups reported higher maximum VM stress than the corresponding groups of Vita Enamic at the finish line and root coronal thirds. However, at the root middle and apical thirds, both materials recorded similar stresses. Conclusions: Short posts and Vita Enamic endocrowns showed minimal stress, especially at the finish line, while long posts increased stress and fracture risk. The findings support conservative restorations without posts, although clinical validation is needed to confirm their long-term effectiveness and safety. Full article

Background/Objectives: This study compared the accuracy and efficiency of different surgical-guide (SG)-assisted and freehand drilling techniques for removing fiber posts from maxillary anterior teeth performed by differently experienced operators. Methods: A fiber post was bonded to the root canal of 54 extracted maxillary anterior teeth. After mounting the teeth in the jaw models, SGs were designed by integrating cone-beam computed tomography (CBCT) and intraoral scanner data. Each SG included a custom sleeve. An experienced or inexperienced operator drilled the post using three different techniques: (i) SG-assisted incremental drilling at 2–3 mm (SG1), (ii) SG-assisted one-time drilling to a predetermined depth (SG2), and (iii) freehand incremental drilling without SG (FH; n = 9 in each group). Deviations in coronal, sagittal, and horizontal planes and the angle of deviation were measured. Results: The SG1 and SG2 groups showed significantly smaller sagittal and horizontal deviations than the FH group, regardless of the operator’s experience. The SG2 group had a significantly shorter working time than the SG1 and FH groups. In the FH group, the experienced operator required a significantly shorter working time than the inexperienced operator. Conclusions: SG-assisted drilling techniques enhanced the accuracy and efficiency of removing fiber posts from the anterior teeth, irrespective of the operator’s experience. Full article

The purpose of the present study was to perform a preliminary analysis of the fitting of different fiber-reinforced composite (GFRC) posts to tooth root canals and determine the resin cement layer thickness. The following GFRC posts were assessed: bundle posts (Rebilda GT^TM, VOCO, Germany), sleeve system (SAP^TM, Angelus Ind, Brazil), and accessory posts (Reforpin^TM, Angelus, Brazil). Twenty-four freshly extracted mandibular single-rooted pre-molars were endodontically treated and divided into six groups, according to the type of GFRC post and resin cement (self-adhesive or conventional dual-cured). Then, specimens were cross-sectioned and inspected by optical microscopy regarding the cement layer thickness and presence of defects such as pores, voids, or fissures were assessed. Bundle and accessory posts revealed a regular distribution of resin cement with a lower number of voids than found with sleeve systems. The sleeve system posts showed poor fitting at the apical portion of the root canals. The type of resin cement did not affect the thickness of the interface, although both bundle and accessory posts allow a better distribution of resin cement and fibers. The present preliminary study reveals interesting insights on the fitting of bundle and accessory posts to root dentin and resin cement layer thickness in oval-shape root canals. The sleeve system posts showed adequate fitting only at the coronal portion of the canals. Full article

(1) Background: The retention of intraradicular posts is an important factor for the prognosis of endodontically treated teeth. The purpose of this study was to evaluate the push-out bond strength (PBS) of the posts relating to their diameter and region of the root. (2) Methods: A total of 40 premolar teeth (decoronated and root canal-filled) were divided into four groups (n = 10). After post-space preparation, different sizes (1.0, 1.2, 1.5, and 2.0 mm) of glass fiber posts were luted with resin cement into the root canals. After placement, 2 mm thick slices were cut from the roots according to their apical, middle, and coronal regions (n = 116). Push-out tests were carried out in a universal testing machine on each slice. A statistical evaluation of the data was applied. (3) Results: When comparing the diameter, the 2.0 mm posts had the highest PBS (111.99 ± 10.40 N), while the 1.0 mm posts had the lowest PBS (99.98 ± 8.05 N). Divided by the surface of the bonded area, the average PBS value was the highest for the 1.0 mm posts (18.20 ± 1.67 MPa) and the lowest for the 2.0 mm posts (12.08 ± 1.05 MPa). (4) Conclusions: Within the limitations of the study, when comparing the regions of the roots, no significant differences were found among the PBS values of the three regions (p = 0.219). When comparing the diameters, significant differences were shown between the PBS values of the four groups (p = 0.023 and p = 0.003, respectively). Full article

Background and Objectives: Although fiber posts are widely used in the restoration of endodontically treated teeth (ETT), their ideal cementation depth into the root canal is still debated in literature. The aim of the present study was to evaluate whether the different intra-radicular insertion lengths of the fiber posts influence the fracture strength of ETT. Materials and Methods: A total of 10 permanent human lower incisors with straight roots of similar length and volume extracted for periodontal reason were sectioned 2 mm above the cement–enamel junction (CEJ) to a total length of 18 mm and endodontically treated in the same manner, then randomly divided into two groups of five each (Groups 1 and 2, n = 5). Two sound incisors, with no endodontic treatment, were used as the control group (Group 3, n = 2). After one week of storage in a humid environment, spaces for fiber post no. 1 (Reforpost, Angelus, Londrina, PR, Brazil) were prepared in the first two groups at a depth of 5 mm (Group 1) and 7 mm (Group 2), and the fiber posts were adhesively cemented using self-adhesive resin cement (Maxcem Elite, Kerr GmbH, Herzogenrath, Germany). After 7 days, the samples were vertically positioned and fixed in a self-curing transparent acrylic resin, up to 2 mm below the CEJ level, and mechanically tested in compression after another week of storage using a displacement-controlled testing machine up to each sample’s fracture. The force–displacement curves were recorded for each sample, the means were calculated for each group and a statistical comparative analysis between groups was conducted. Results: Although no statistically significant differences between groups were observed, the highest mean fracture force (N) was recorded in Group 2 (1099.41 ± 481.89) in comparison to Group 1 (985.09 ± 330.28), even when compared to the sound, non-treated teeth (1045.69 ± 146.19). Conclusions: Within the limitations of this in vitro study, teeth where fiber posts were placed deeper into the root canal (7 mm) recorded slightly higher fracture forces in comparison with shorter lengths (5 mm). However, similar biomechanical performances obtained in the mechanical tests showed no statistical differences between the 7 mm and the 5 mm inserted posts. Full article

The aim of this study was to assess adaptation and bonding to root canal dentin of discontinuous (short) glass fiber-reinforced composite to intra-radicular dentin (DSGFRC). Methods: Seventy virgin human teeth were extracted and then endodontically treated; then samples were randomly divided into 7 groups (n = 10), based on the materials’ combinations as follows: Group 1, a two-bottle universal adhesive + DSGFRC; Group 2, a single-component universal adhesive + DSGFRC; Groups 3 and 4, the same materials of Goups 1 and 2 were used but after cleaning of the canal walls with 17% EDTA and final irrigation with 5.25% NaOCl Ultrasound Activated (UA); Group 5, traditional prefabricated fiber posts were luted after being silanized with G-Multi Primer; Groups 6 and 7, like Group 5 but after ultrasonic irrigation (UA). All sample roots were cut 1 mm thick (n = 10) to be evaluated regarding root canal adaptation using a light microscope and scanning electron microscope (SEM) and push-out bond strength. These results were statistically analyzed by Kruskal–Wallis analysis of variance by ranks. The level of significance was set at p < 0.05. Results: Bond strength forces varied between 6.66 and 8.37 MPa and no statistically significant differences were recorded among the groups. By microscopic examination, it was noted that ultrasonic irrigation increased the adaptation of the materials to the dentin surface. Conclusions: Within the limitations of this in vitro study, it may be concluded that when DSGFRC was used for intracanal anchorage in the post-endodontic reconstruction, similar push-out retentive force and strength to those of traditional fiber posts cemented with particulate filler resin composite cements were achieved. Full article

This in vitro study evaluated the accuracy of guided endodontics for the removal of intraradicular fiberglass posts from posterior mandibular teeth and the influence of the operator’s experience in this procedure. Forty root-filled mandibular first molars with an intraradicular fiberglass post were mounted onto 20 mandibular models. Guides for access were made following surface scanning and cone-beam computed tomography (CBCT) using CoDiagnostix software. The models were randomly divided between two operators (n = 20). One was an inexperienced dental surgeon (IN), and the other was a dentist experienced in the guided technique (EX). A postoperative CBCT scan was superimposed on the initial planning, and the means were calculated for the angle and for 3D deviation. The 95% confidence interval (CI) was calculated, and differences between groups were assessed by a t-test. The mean deviation angle was 2.54° (0–5.85°) for IN and 1.55° (0–2.85°) for EX. The mean 3D deviation was 0.44 mm (0.14–0.73 mm) for IN and 0.33 mm (0.11–0.76 mm) for EX. The means of the angle and 3D deviation were significantly different (p = 0.008 and p = 0.049). Guided endodontics was influenced by the operator and allowed access for removing intraradicular fiberglass posts with minimal deviation and greater accuracy for an experienced operator compared with an inexperienced one. Full article

Recent formulations of resin-based composites have incorporated different combinations of materials. However, the mechanical and bonding behavior of these materials with intraradicular posts are unclear. This study aimed to evaluate the effect of light-cure and dual-cure resin composite posts on the fracture resistance of endodontically-treated teeth. Materials and Methods: Ninety extracted human upper canines were selected and randomly divided into nine groups (n=10): (G1) endodontically treated teeth without endodontic posts; (G2) glass-fiber post cemented with glass-ionomer cement; (G3) endodontic post by dual-cure composite resin (Rebilda DC); (G4) endodontic post by dual-cure composite resin (Cosmecore); (G5) endodontic post by dual-cure composite resin (Bis-Core); (G6) endodontic post by light-cure composite resin; (G7) glass-fiber post customized with flowable composite resin; (G8) glass-fiber post cemented with light-cure composite resin; (G9) glass-fiber post cemented with self-adhesive resin cement. After the post insertion, all specimens were subjected to mechanical (250,000 cycles) and thermocycling (6000 cycles, 5 °C/55 °C) and immediate loading at 45 degrees in a universal testing machine until fracture. The data were analyzed by one-way ANOVA and multiple comparisons using the Fisher LSD Method (p < 0 05). Results: The mean failure loads (±SD) for the groups ranged from 100.7 ± 22.6 N to 221.9 ± 48.9 N. The G1 group (without endodontic posts) had a higher fracture strength than all experimental groups (p < 0.001). Conclusions: Within the limitations, the light- and dual-cure post technique did not present lower fracture resistance values as compared to the conventional glass-fiber post. Full article

Persistent apical periodontitis occurs when the endodontic treatment fails to eradicate the intraradicular infection, and is mainly caused by Gram-positive bacteria and yeasts, such as Enterococcus faecalis and Candida albicans, respectively. Phenothiazines have been described as potential antimicrobials against bacteria and fungi. This study aimed to investigate the antimicrobial potential of promethazine (PMZ) and chlorpromazine (CPZ) against E. faecalis and C. albicans dual-species biofilms. The susceptibility of planktonic cells to phenothiazines, chlorhexidine (CHX) and sodium hypochlorite (NaOCl) was initially analyzed by broth microdilution. Interaction between phenothiazines and CHX was examined by chequerboard assay. The effect of NaOCl, PMZ, CPZ, CHX, PMZ + CHX, and CPZ + CHX on biofilms was investigated by susceptibility assays, biochemical and morphological analyses. Results were evaluated through one-way ANOVA and Tukey’s multiple comparison post-test. PMZ, alone or in combination with irrigants, was the most efficient phenothiazine, capable of reducing cell counts, biomass, biovolume, carbohydrate and protein contents of dual-species biofilms. Neither PMZ nor CPZ increased the antimicrobial activity of CHX. Further investigations of the properties of phenothiazines should be performed to encourage their use in endodontic clinical practice. Full article

This study assessed the bond strength of prefabricated post systems at different root levels of endodontically treated teeth. One-rooted human premolars (N = 70; n = 10) were cut to 2 mm above the cement-enamel junction. Root canals were treated and randomly assigned to one of the seven post systems: T: Titanium (Mooser), ZrO: Zirconia (Cosmopost), G: Fiber (FRC Postec Plus), E1: Fiber (Direct) (Everstick post), E2: Fiber (Indirect) (Everstick post), PP: Fiber (PinPost), and LP: Injectable Resin/Fiber composite (EverX Posterior). All posts were luted using a resin cement (Variolink II), and the roots were sectioned at the coronal, middle, and apical root levels. Push-out tests were performed in the Universal Testing Machine (0.5 mm/min). Data (MPa) were analyzed using two-way ANOVA and Tukey’s tests (α = 0.05). The results showed that the bond strength (mean ± SD) of E2 posts were highest (5.3 ± 2.7) followed by PP (4.1 ± 2.0); G (4.0 ± 1.6); LP (2.6 ± 1.9): T (2.2 ± 1.5) and ZrO (1.9 ± 1.0) posts systems. No significant differences were found in bond strength of all post systems. The bond strength in the coronal root level was the highest with 3.6 ± 2.2 MPa. The bond strength of FRC post systems was significantly higher than those of rigid posts of titanium or ZrO₂. Bond strength results were the highest in the coronal root level for all tested post systems but did not differ significantly from the other two root levels. Full article

Background: Diode-assisted endodontics is nowadays utilized for pulp space disinfection, but little is known on the bonding potential of this lased root dentin when the tooth is restored with an intracanal polymer post. Objectives: to investigate the influence of diode laser irradiation settings, in laser-assisted endodontics, on the intraradicular bonding of composite materials. Methods: Sixteen two-rooted, maxillary first premolars were collected, prepared up to F4 (Protaper Universal. Dentsply-Maillefer, Ballaigues, Switzerland), and randomly assigned in two groups: group A (chopped mode or short pulse), diode irradiated according to protocol, pulse 25 ms, power 2.5 W, and group B (microchopped mode or ultrashort pulse), pulse 25 μs, peak power 12 W (both groups GentleRay. KaVo Dental, Biberach an der Riss, Germany). Buccal canals were irradiated, palatal ones served as controls. Canals were then obturated, post space was created in all canals, and quartz-fiber posts (ICE light Danville. Danville Materials, San Ramon, CA, USA) were cemented by self-etch self-curing cement (Max Cem Elite. Kerr, West Collins Orange, CA, USA) (Max Cem Elite. Kerr, Brea, CA, USA). A week later, teeth were sectioned horizontally in 1 mm increments. Push-out test was conducted in a Zwick testing machine (Zwick Roell, Ulm, Germany) at 1 mm/min speed, and the force required to dislodge the post from each specimen (F-max) was recorded. Weibull regression models were applied for statistical analyses. Results: Differences in F-max by group (control vs. chopped mode vs. microchopped mode) and height (meaning the apical-to-coronal position of each specimen along the root) were statistically significant (p < 0.05 in all cases). Conclusions: Short pulses (or chopped mode) had a profound positive effect on the quality of intraradicular bonding, while Ultrashort pulses (or microchopped mode) affected it negatively. In addition, apically positioned bonding proved weaker compared with more coronally located specimens. Full article