Comparison of Class II Bulk-Fill, Self-Adhesive Composites, Alkasite, and High-Viscosity Glass Ionomer Restorations in Terms of Marginal and Internal Adaptation.

(1) Background: Restoring decayed teeth in young patients can be challenging. This calls for a simplification of the protocols through new biomaterials. Therefore, the aim of this study was to compare the marginal adaptation delivered by restorative materials applied on class II cavities by using a simplified protocol, before and after fatigue test, followed by the assessment of the internal adaptation. (2) Methods: Forty-eight human teeth were divided into six groups (n = 8). Dentinal fluid simulation was performed before restoring the class II cavities: Gr 1-adhesive (Clearfil Universal Bond Quick) and nanohybrid flowable composite (Clearfil Majesty ES Super Low Flow), Gr 2-adhesive (Clearfil Universal Bond Quick) and nanohybrid composite (Clearfil Majesty ES standard), Gr 3-bulk fill self-adhesive composite (Surefil One), Gr 4-bioactive powder-liquid filling material (Cention Forte), Gr 5-universal adhesive (Adhese Universal) and nanohybrid composite resin (Tetric Powerfill); and control group (CT)-high-viscosity glass ionomer (Equia Forte). Marginal adaptation was observed with scanning electron microscopy (SEM) and compared before and after a fatigue test consisting of repeated thermal and mechanical cycles. The specimens were then cut mesio-distally, and internal adaptation was undertaken using SEM again. Repeated measures and one way ANOVA followed by a Fisher's LSD test and Fisher's LSD post hoc test were used in order to compare the statistically significant differences among groups. (3) Results: As for the marginal adaptation after loading, Cention Forte (58%) and Equia Forte HT (53%) were statistically equivalent and presented the highest results, followed by Clearfil Majesty ES Standard (32%) and Tetric Powerfill (27%), with Surefil One (8%) and Clearfil Majesty ES Flow Super Low (7%) showing the worst results. In terms of internal adaptation, Cention Forte (85%) and Clearfil Majesty ES Standard (74%) had the highest percentages of continuous margins. Tetric powerfill (56%) and Equia Forte HT (44%) showed statistically significantly lower results, followed by Clearfil Majesty ES Flow Super Low (33%) and eventually Surefil One (17%). (4) Conclusions: This in vitro study showed promising results for the marginal and internal adaptation of alkasite dual cured Cention Forte in the restoration of class II cavities. This material could be considered an interesting restorative alternative for the restoration of deciduous teeth.

An in vitro study on the influence of laser-activated irrigation on infiltration and leakage of a dual curing-resin cement as an endodontic sealer.

Objectives: The study aims to investigate the effects of laser-activated irrigation on infiltration and microleakage of a dual-curing resin cement applied as a root canal sealer. Methods: Thirty-eight extracted upper molars were attributed to four experimental groups. Roots were mechanically enlarged and disinfected (NaOCl). Control samples (n = 11) were irrigated with conventional needles and three different lasers were used to activate the irrigant in the other groups (n = 9): 2.94 µm Er:YAG laser, 9,300 µm CO2 laser and 808 nm diode laser with a modified black coated laser tip. Final irrigation was performed in each group with ethylenediaminetetraacetic acid (EDTA), sodium hypochlorite (NaOCl) and sodium chloride (NaCl) activated with lasers and in the control without activation.Dentin tubules were then labeled with a red fluorophore (Rhodamine B) and the root canals were sealed with a dual-curing resin cement (Paracore). The cement fixed the dye on the sealed and infiltrated dentin parts. To remove the Rhodamine not fixed by the cement, roots were then sectioned horizontally and immersed in hydrogen peroxide (H2O2). The empty dentin tubules spaces were then labeled with a green fluorophore (Fluorescein) allowing the visualization of infiltration and microleakage by confocal microscopy. Results: Percentages of infiltration were significantly higher in the middle root third of the control and Er:YAG laser-activated samples compared to CO2 or diode laser groups. Microleakage was present in all experimental groups but significantly less after CO2 laser activation. Conclusion: Laser-activated irrigation impacted resin cement infiltration and microleakage dependent on the applied wavelength. Er:YAG laser activation led to higher values of infiltration and microleakage compared to CO2 and diode lasers.

An in-vitro study on effects of laser activation on dye penetration in human root dentin.

Objective: To evaluate the penetration of a dye in root dentin after activation with different laser wavelengths. Materials: Palatal roots of 38 human molars were enlarged and disinfected. Irrigation activation was performed with an Er:YAG laser: @50 mJ, 15 Hz (Er:YAG); a 9.3 µm CO2 laser: @40% power (CO2); diode lasers 455 nm/970 nm: @0.8 W, 15 Hz (D455, D970) and 808/980 nm: @1 W (D808, D980) and compared to positive control: etching with 35% H3PO4 (POS); negative control: water (NEG) and conventional needle irrigation: NaOCl and ethylenediaminetetraacetic acid (EDTA) (CONV). Methylene blue solution was introduced in the canal and laser-activated or left untouched for 100 s before the roots were dried and cut into horizontal slices. Dye penetration was automatically calculated by color recognition of two samples per root third (n = 8 per group in each coronal, middle and apical root thirds). The presence and absence of a smear layer was checked in two additional samples of the negative and positive control under scanning electron microscopy (SEM). Results: Full-depth infiltration was not achieved in any group. Dye penetration in CONV was significantly less than in Er:YAG, CO2, POS, D455, D970, D808 and similar to NEG and D980 when results of different root thirds were pooled. Conclusion: Laser activation using certain parameters enhanced dye penetration compared to conventional needle irrigation with NaOCl and EDTA (CONV).

Marginal adaptation of two-step self-etch versus universal adhesives for Class V restorations: Effect of Er:YAG laser vs. bur prepared cavities.

PURPOSE: To compare the in vitro effect of laser and bur preparation on marginal adaptation of Class V cavities restored with a 2-step self-etch and distinct universal one-component universal adhesives used in self-etching mode. METHODS: 96 Class V cavities were prepared with conventional burs or with an Er:YAG laser. Four universal self-etch (Unibond Extra Low Shrinkage, All Bond Universal, SKB-100 and Prime&Bond active) and a 2-step self-etch adhesive (Clearfil SE Bond) that served as control were used to restore the cavities with direct composite. The percentages of continuous margins were evaluated by quantitative SEM analysis before and after a fatigue test consisting of 240,000 occlusal loads and 600 warm/cold thermal cycles. RESULTS: The marginal adaptation of bur prepared restorations was statistically superior to laser-prepared ones. Class V cavities restored with Clearfil SE Bond and the one-component self-etching universal adhesives All Bond Universal and Prime&Bond active presented the highest and statistically similar percentages of continuous margins before and after loading under both bur and laser cavity preparation. The lowest percentages of continuous margins were observed in the groups restored with the low shrinking adhesive (Unibond ELS), with medians of 49 and 21 for bur and laser prepared cavities after loading. CLINICAL SIGNIFICANCE: Class V cavities presented smoother and higher percentages of continuous margins when prepared by bur rather than by laser. The 2-step self-etch adhesive Clearfil SE Bond and 1-step self-etch universal adhesives All Bond Universal and Prime&Bond active showed a comparable marginal performance.

Activation of endodontic irrigants using a 9.3 µm CO2 and diode lasers: A laboratory proof of concept model.

PURPOSE: To investigate the differences between irrigant propagation and temperature changes using laser-activated irrigation (LAI) at different settings in an artificial root canal model. METHODS: Using an artificial resin root canal model, irrigant activation was achieved in 19 experimental groups with eight samples each. A 9,300 nm CO2 laser, two diode lasers with different settings (wavelengths 455, 808, 970, and 980 nm) were compared to 2,940 nm Er:YAG laser and traditional needle irrigation. Er:YAG and CO2 laser were activated in the pulpal chamber only, while diode lasers and needles were inserted into the main root canal. Lasers were activated for 5x 20 seconds resulting in 100 seconds of activation or rinsing for each sample. After each activation of 20 seconds, a photo was taken of the side canals and the propagation of the dye was measured with a digital measuring tool after calibration. Further, the temperature of the irrigant was reported after activation of 20 seconds and repeated 5 times. Data were checked for normality and statistically compared. RESULTS: All lasers increased the irrigant propagation compared to conventional irrigation. Significant differences were found between groups regarding propagation and temperature (P< 0.0027). Er:YAG and CO2 laser had similar effects on irrigant propagation in middle and apical located side-canals with specific power parameters and were superior to diode lasers and syringe irrigation. The irrigant's temperature increased significantly with the diode and CO2 lasers. CLINICAL SIGNIFICANCE: Diode lasers and CO2 lasers have not been established for irrigant activation. 9,300 nm CO2 lasers absorb well in water and were shown to introduce vapor bubble formation and streaming in water. Diode lasers are highly accepted in periodontics. The laser light is not absorbed in water but interacts with bacteria as well as soft tissues and contributes therefore to infection control. With a modified laser tip it was however possible to introduce cavitation and streaming in irrigants.

Marginal Adaptation of In Vitro Class II Restorations Made Out of Bulk or Conventional Composite Using Single- or Multi-Layered Techniques.

Objective: Testing the influence of various restorative materials (conventional or bulkfill composites) and filling techniques (single- or multi-layered techniques) on the in vitro marginal adaptation of large class II direct composites with supra and sub-gingival margins subjected to thermomechanical loading (TML). Methods: A total of 40 prepared teeth were attributed randomly to five experimental groups. In Group 1, restorations were made of multi-layered high-viscosity conventional composite (Tetric EvoCeram); in Groups 2 and 3, restorations were made of a high viscosity bulkfill composite (Tetric EvoCeram Bulk Fill) applied in one (Group 2) or three layers (Group 3); in Groups 4 and 5, restorations were made of a flowable bulkfill composite (SDR flow) applied in one (Group 4) or two layers (Group 5), covered with a layer of high-viscosity conventional composite (Ceram-X Universal). A single adhesive (OptiBond FL) was used in all groups. All specimens were submitted to a staged TML comprising three phases (2 × 500,000 and 1,000,000 cycles) at 50 N with 3350 thermal cycles (5 to 55 °C) every 500,000 cycles. The tooth-restoration interfaces on proximal surfaces were evaluated quantitatively by scanning electron microscopy, before and after each TML phase, hence at three timepoints (T0, T1, T2 and T3). The following segments were considered for evaluation: proximal, vertical enamel margins (assessed individually on both restoration sides), cervical enamel (restoration side above CEJ) and cervical dentin margin (restoration side below the CEJ). Results: TML induced a significant reduction in continuous adaptation at both enamel and dentin margins in all groups, with percentages of continuous margins ranging from 75.2 to 91.8% at T0, and decreasing to values ranging from 21.3 to 73.9% at T3. Both composite systems and layering protocols had a significant influence on marginal adaptation of the restorations, with statistical associations depending on the restoration group and the timepoint considered. Defective margins in enamel were all of a cohesive nature with micro-fractures, while in dentin, interfacial gaps were the main defect observed. Conclusions/Clinical significance: The present results highlighted significant degradation of marginal adaption after long-term in vitro fatigue test using materials even with high-viscosity conventional resin composites, applied with a proper layering approach in medium-large sub-gingival cavities. While no significant differences were observed at the dentin cervical margins, there was a tendency for better adaptation at the enamel margin when using a higher modulus material with a multi-layered technique.

In Vitro Evaluation of Tooth-Whitening Potential of Peroxide-Free OTC Dental Bleaching Agents.

Purpose: To evaluate and compare the tooth-whitening potential of five over-the-counter (OTC), peroxide-free dental bleaching methods as well as an experimental tooth-whitening solution containing 0.1% hydrogen peroxide complexed with doping agents with a gold standard (positive control) containing 16% carbamide peroxide. Material and Methods: Eighty permanent bovine incisor teeth were randomly allocated to eight different groups. Two teeth from each group were immerged into five staining solutions represented by coffee, tea, red wine, and curry mixed in warm oil or distilled water (control group) and stored at 37 °C for 28 days in an incubator. The teeth were then reallocated to the eight groups, resulting in ten samples per group, and each group was matched with a bleaching product. The bleaching procedures were executed following the manufacturer's recommendations. The color of each sample was assessed over a white and black background using a quantitative numerical measurement approach with a calibrated spectrophotometer. Spectrophotometric measurements were performed after exposing the teeth to the bleaching agent for 60 min (T2), 100 min (T3), and 200 min (T4), and ΔE00 was calculated. Results: When analyzed over a white background, the mean ΔE00 values ranged from 2.14 (placebo) to 6.32 (Opalescence PF). When analyzed over a black background, the mean ΔE00 values ranged from 2.31 (placebo) to 5.78 (Opalescence PF). Statistically significant ΔE00 color changes over time for the eight groups and five staining solutions at T1 and T4 were assessed for both backgrounds using repeated ANOVA followed by Fisher's LSD post hoc test (p-value < 0.01). Conclusions: All tested over-the-counter whitening kits except one exhibited positive color variation. However, the individual performance differed vastly from one brand to the other, and the overall performance was less effective compared to the conventional carbamide-peroxide-based positive control.

Efficacy of one-time application of low-level laser therapy in the management of complications after third molar surgery: A retrospective practice-based study.

PURPOSE: To evaluate in a retrospective practice-based clinical study, the effects of additional laser therapy on side effects following the removal of all four impacted third molars. The secondary objective was, based on those results, to rationalize a protocol for low-level laser therapy (LLLT) in terms of irradiation settings. METHODS: 96 subjects requiring simultaneous surgical removal of the four third molars were treated from 2017 to 2019. For each subject, one side was randomly assigned to laser treatment, the other receiving the placebo. LLLT was performed by applying an infrared diode laser of 810 nm. In the LLLT irradiated side of the mouth, three groups were randomly assigned to a specific protocol of irradiation. Controllable settings include power, energy density and also scanning technique. The main outcome was pain, registered on a visual analog scale (VAS) performed by the patients. RESULTS: There was a statistically significant difference for one of the tested protocols. Self-reported annoyance and pain scores were lower for the side submitted to a 30-second laser radiation at a power of 0.3 W with the slow scanning technique (P< 0.05). CLINICAL SIGNIFICANCE: The present treatment approach, using a one-time low-level laser therapy intra-oral application, showed a beneficial effect of LLLT reducing pain after third molar surgery, which should be confirmed through further study.

Time-and cost-effective 3-dimensional-printing workflow to rehabilitate worn dentitions: A clinical report.

Current restorative methods of restoring worn or eroded dentition present drawbacks that may deter dentists or patients from pursuing complete mouth rehabilitation. A novel additive manufacturing approach using 3D-printed definitive composite resin restorations is described as a less technique-sensitive and more cost-effective alternative. These restorations are straightforward to repair, modify, or replace.

Evaluating the use of self-conditioning adhesive combined with dual curing resin cement as an endodontic sealer: An in vitro study.

Objectives: To compare infiltration, sealing and microleakage in root dentin with a self-conditioning adhesive system combined with dual curing resin (resin-based cement) to a conventional epoxy-resin-based sealer using confocal microscopy imaging. Methods: 26 roots were enlarged and disinfected. Dentin tubules of 24 teeth were labelled with a red fluorophore (Rhodamine B) (two samples served as controls). Root canal samples were sealed in group AH (n = 11) with a conventional sealer (AH Plus Root Canal Sealer, Dentsply DeTrey) and in group RC (n = 11) with a resin-based cement (Parabond combined with Paracore, Coltène). Roots were then sectioned horizontally and immersed in H2O2 to remove the Rhodamine B not fixed by the sealers. The empty dentin spaces were labeled with a green fluorophore (Fluorescein) enabling the evaluation of infiltration as well as microleakage by confocal microscopy. Two additional samples were fractured in vertical direction for observation under SEM. Results: Group RC presented significantly more infiltration in the middle third than in the middle and apical thirds of group AH. Microleakage was significantly higher in group AH than in group RC. SEM images revealed more dentin plugs and a homogenous resin layer in group RC in contrast to group AH. Conclusion: The resin-based cement revealed promising outcomes compared to a traditional epoxy resin based sealer.

Infiltration and microleakage in infiltrated and sealed root dentin samples are higher in middle than apical root thirds. Root dentin infiltration and sealing with a self-conditioning adhesive system and a dual-curing resin cement revealed less microleakage than with an epoxy-resin-based sealer.