Aline Evangelista Souza-Gabriel

Colored fiber posts facilitate clinical retrieval but could impact esthetics and bonding. This study evaluated the color stability and dentin bond strength of a novel colored fiber post designed to facilitate post‐removal. Sixty premolars had root canal therapy and post space preparation. Color parameters (Δ L *, Δ a *, Δ b *) were measured with a spectrophotometer. Specimens were divided into two groups: control—Exacto post (Angelus); experimental—blue‐colored fiber post (patent granted). A flowable resin was used for core build‐up, and restoration was done with a composite resin (shade A2). Overall color change (Δ E * ab ) and whiteness index variation (Δ WI ) were calculated ( n = 10). Push‐out bond strength was assessed at 24 h ( n = 10) and 12 months ( n = 10). Data were analyzed using anova , Tukey's post hoc, and chi‐square tests ( α = 0.05). No significant differences were found between groups for Δ E * ab or Δ WI . After aging, both groups showed increased Δ E * ab and Δ WI . Bond strength was similar between groups, although both decreased over 12 months. Adhesive failure was predominant in both groups. The experimental colored fiber post demonstrated esthetic and mechanical performance comparable to a conventional fiber post, offering a potential alternative for restoring endodontically treated teeth with enhanced retreatability and safety.

Residual temporary cement may hinder fiber post bonding. Therefore, efficient root canal cleaning protocols are essential. This study investigated the effects of three cleaning methods on bond strength, adhesive interface quality as evaluated using scanning electron microscopy (SEM), and intratubular penetration of a self-adhesive resin cement as evaluated using confocal laser scanning microscopy (CLSM). Forty-two mandibular premolars were prepared using Reciproc R50, filled with AH Plus, and restored with provisional retainers cemented with Bifix Temp. Specimens were allocated to three groups (n = 14) according to the cleaning protocol: standardized drill (SD), drill with an ultrasonic insert (UI), or drill with a prophylactic brush (PB). Fiber posts were cemented using a self-adhesive resin cement. Push-out testing, failure mode analysis, and SEM/CLSM evaluations were performed. Bond strength (MPa) was analyzed using two-way ANOVA followed by Tukey's test, whereas failure patterns were analyzed using the chi-square test, and interface adaptation was analyzed using nonparametric tests. PB (4.42 ± 2.60 MPa) and UI (4.55 ± 2.41 MPa) showed significantly higher bond strength values and greater cement penetration than SD (3.04 ± 1.70 MPa) (p < 0.05). Mixed adhesive failures predominated, and SEM revealed no significant differences in interface adaptation. Cleaning with a PB or UI enhanced adhesive performance and resin cement penetration during fiberglass post cementation.

The aim of this study was to evaluate changes in tooth color and the bond strength of resin to enamel and dentin after exposure to electronic cigarette (e-cigarette) vapor in an in vitro vaping model, as well as to analyze the chemical composition of the materials present in the vapor. A device with a vacuum pump simulated vaping. Eighty dental slabs (40 dentin and 40 enamel) and were randomly divided into two groups. Half received e-cigarette exposure, and the other remained without vaping (control). Color changes were measured using a spectrophotometer (CIELAB). Composite cylinders were built on substrates using etch-and-rinse or self-etch strategies and subjected to loading tests. Gas chromatography-mass spectrometry (GC–MS) analyzed the organic compound of the e-liquid, while inductively coupled plasma mass spectrometry (ICP-MS) assessed the metal content. Statistical analysis was conducted using MANOVA and ANOVA (α = 0.05), and CIEDE2000 formula. E-cigarette exposure darkened (L*) and yellowed (b*) enamel and dentin. Bond strength in dentin decreased for both adhesion strategies, and in enamel using the etch-and-rinse adhesive. GC–MS identified 72 different volatile compounds, whereas ICP-MS detected 26 distinct metals. Among metals, eight exceeded the WHO (World Health Organization) tolerance limits. E-cigarette exposure altered the color of substrates and reduced resin bond strength in dentin for both adhesives, and in enamel restored with the etch-and-rinse technique. E-liquid had toxic organic compounds and metals. Exposure to e-cigarette can cause tooth discoloration and weaken bonding to dental tissues. Toxic volatile organic and metallic compounds present in vapor can adversely affect oral health.

Background To evaluate the biomechanical performance of weakened maxillary incisors restored with glass fiber posts (GFPs), polyethylene fiber reinforcement, or CAD/CAM (computer-aided design/computer-aided manufacturing) endocrowns (ECs), focusing on fracture resistance, failure mode, and crack formation after thermomechanical aging. Methods Fifty maxillary central incisors were allocated into five groups (n = 10): sound tooth (ST, control); glass fiber post (GFP) + CAD/CAM crown; polyethylene fiber in a "U" pattern (PFU) + CAD/CAM crown; polyethylene fiber in a "C" pattern (PFC) + CAD/CAM crown; and CAD/CAM EC. All experimental groups underwent root canal treatment and weakening. Specimens were subjected to 1.4 million thermomechanical cycles and loaded to fracture. Fracture mode was examined under stereomicroscopy, and cracks were analyzed via micro-CT. Fracture resistance (N) was analyzed with ANOVA and Tukey's HSD (α = 0.05), while failure and crack types were compared using Kruskal-Wallis tests. Results ST had the highest fracture resistance (990.8 ± 107.8 N), followed by PFC (800.5 ± 139.1 N). PFU (649.4 ± 146.8 N) and GFP (616.6 ± 122.3 N) showed intermediate values; EC had the lowest (461.1 ± 146.3 N). Most failures were favorable, but 30% of EC samples failed catastrophically. PFC and PFU preserved more crack-free roots (70% and 60%), while GFP exhibited multiple vertical cracks. Conclusion Polyethylene fiber reinforcement, regardless of fiber orientation, significantly improves fracture resistance and reduces root cracking in endodontically treated incisors. This technique may provide a reliable alternative to fiber posts and CAD/CAM ECs in the restorative dentistry of anterior teeth.

Objectives Post-removal can be challenging and may increase the risk of iatrogenic damage during endodontic retreatment. This study evaluated the efficacy and efficiency of removing a novel fiber-colored post specifically designed to facilitate retrieval. Materials and methods Twenty mandibular premolars were instrumented with an R50 file and irrigated using 2.5% NaOCl and 17% EDTA under ultrasonic agitation. The roots were filled with AH Plus, and post spaces were prepared. Micro-CT scans were performed before post-cementation and after post-removal. Specimens were divided into two groups: Control – Exacto post (Angelus) and Experimental – fiber-colored post (patent granted). Post-removal was performed under magnification with ultrasonic tips activated for 20-second intervals, with pauses for tip cooling, canal irrigation and drying. Outcomes included working time, dentin loss, residual material, canal deviation, and procedural quality. Data were analyzed using the T-test and Mann-Whitney at 5%. Results The fiber-colored post showed a significantly shorter removal time (p = 0.023), with less dentin loss and residual material (p < 0.0001). The control group exhibited severe deviations from the root axis and a 30% perforation rate, whereas fiber-colored posts had no perforations and most samples without deviation (p < 0.0001). Conclusions The experimental fiber-colored posts enhanced removal efficiency, safety, and predictability. Clinical relevance Fiber-colored posts represent a promising restorative alternative that can facilitate post-removal during reintervention, helping to prevent iatrogenic damage and preserve tooth structure.

To evaluate the effect of biomechanical preparation on irradiated root dentin after the use of different endodontic instrumentation techniques. Sixty mandibular canines were randomly assigned to two groups: non-irradiated (30 canines) and irradiated (30 canines subjected to 30 cycles of 2 Gy, totaling 60 Gy). After radiotherapy, the samples were scanned using micro-CT to assess the 3D morphology of the root canal and to calculate the length, thickness, volume, surface area and transport of the canal. The groups were redistributed into 3 subgroups (n = 10) according to the instrumentation protocol: GI—manual M-easy Ni–Ti file up to #50.05; GII—rotary instrument ProTaper Next up to #50/.06; GIII—reciprocating instrument Reciproc #R50. After instrumentation, the specimens were scanned again in micro-CT following the same parameters as the initial acquisition. Statistical analysis was performed using two-factor analysis of variance (ANOVA) test with Tukey’s post-test considering the variables “instrumentation protocol” and “radiotherapy”. The three-factor ANOVA test with Tukey’s post-test was carried out to compare the influence of radiotherapy, instrumentation and root thirds (cervical, middle and apical) on root canal transportation data. Irradiated teeth showed a greater increase in surface area and percentage of walls touched, while for root canal transport and volume, differences were observed only in relation to the type of preparation, in ascending order for the manual, rotary and reciprocating systems. Descriptive analysis showed that altered thickness in the middle-apical thirds occurred mainly in teeth irradiated with rotary and reciprocating instrumentation protocols. Irradiation of teeth can affect biomechanical preparation parameters of different instrument kinematics used to prepare canine root canals.

Patients seeking a harmonious smile that combines satisfactory aesthetics and stable occlusion raise questions about the concomitant association of treatments. This systematic review aimed to answer the following question: "Does the application of hydrogen peroxide on teeth with fixed metallic orthodontic brackets interfere with the dental bleaching effect?". The PICOS (Population, Intervention, Comparison, Outcome, and Study design) strategy and the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were adhered to during the review process. A comprehensive search strategy was implemented, encompassing the PubMed®, Web of Science, Scopus, Embase, and LILACS databases. The risk of bias was assessed using the Cochrane risk of bias (RoB) 2.0 tool. The initial search yielded 51 articles, which were then filtered to remove duplicates. The titles and abstracts of 26 studies were subsequently reviewed. Eleven articles were selected for full-text reading, and after applying the eligibility criteria, 3 studies were included for qualitative analysis. Two studies were classified as having a low risk of bias, while 1 study was classified as having some concerns. The bleaching was satisfactory with 8% and 10% hydrogen peroxide (HP) applied for 45 min daily over 10 days, even with fixed orthodontic brackets. However, a single study that employed the in-office technique (38% HP) demonstrated that fixed orthodontic appliances influenced external tooth bleaching. Tooth bleaching using the home bleaching technique yielded effective results when performed alongside orthodontic treatment.