Restoring an Extremely Destructed Tooth with Flared Root Canal Walls: A Case Report.

Reconstructing severely damaged teeth has always presented a challenge when the remaining crown structure is limited, often requiring retention from the root canal using intracanal posts. However, the real challenge is when the root canal walls are also weak, and there is a high risk of vertical root fracture due to the wedging forces of a rigid post. This case report presents a tooth with extremely flared (0.3mm) root canal walls, successfully restored with a newly introduced polymer made of polyether ether ketone (PEEK), with one-year follow-up. Due to its close elastic modulus to dentin, capacity to bond effectively to tooth structure, shock-absorbing properties, and thereby facilitating favorable stress distribution, utilizing this material for an intracanal post has the potential to mitigate the risk of fractures often associated with cast metal posts. It combines the good fitness of cast posts with the low modulus of elasticity and optical properties of prefabricated fiber posts.

Effect of pH of In-Office Bleaching Gels and Timing of Fluoride Gel Application on Microhardness and Surface Morphology of Enamel.

Objective: To assess microhardness (VH) of enamel treated with two in-office bleaching agents with different pH and to study the effect of post- and prebleaching fluoride therapy. Materials and Methods: Eighty bovine incisors were divided into eight groups: G1-Unbleached group; G2-2% NaF; G3-Pola Office (pH = 3.8); G4-Pola Office+ (pH = 7); G5-Pola Office followed by 2% NaF; G6-2% NaF followed by Pola Office; G7-Pola Office+ followed by 2% NaF; G8-2% NaF followed by Pola Office+. Bleaching was conducted 3x with 1-week intervals (T1/T7/T14). Specimens were kept in artificial saliva. VH was measured at T1, T7, and T14. Data were analyzed using repeated measure ANOVA. Surface morphology was assessed using scanning electron microscopy. Result: There was no significant difference among the groups at T1. No significant difference was found between G3 and G4 at all intervals. 2% NaF (G5/G6 vs. G3) significantly prevented softening at T7 and T14. Some nonsignificant hardening was observed for 2% NaF for G7/G8 vs. G4. At T14, G3 showed the lowest VH values. G5 showed higher VH values compared to other groups apart from G6-G7. No relationship between bleaching protocols and surface morphology was observed. Conclusion: Pola Office caused the most softening. 2% NaF gel application after Pola Office bleaching was effective in recovering enamel hardness. Fluoride application after Pola Office+ bleaching provided little benefit.

Comparing short implants to standard dental implants: a systematic review and meta-analysis of randomized controlled trials with extended follow-up.

PURPOSE: To compare the difference of marginal level changes (MBL), implant failure (IF), biological and prosthetic complications (BC and PC), and prosthetic failure (PF) of short implants (SH) and standard implants (ST). MATERIALS AND METHODS: Electronic searches (PubMed, Web of Science, EMBASE, Scopus, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov) and manual searches were performed to identify all randomized controlled trials (RCTs) evaluating SH to ST. Applying Stata, a meta-analysis was conducted on the weighted mean difference (WMD) and standardized mean difference (SMD) of MBL and the risk difference (RD) of the secondary outcome. RESULTS: Twenty-four articles were involved in the present study. There were statistically significant differences in MBLs, preferring short implants in the maxilla (WMD: -0.147 (CI: -0.224, -0.070), I2: 76.6%; SMD: -0.757 (CI: -1.226, -0.289), I2: 89.2%) and in the mandible (WMD: -0.377 (CI: -0.656, -0.098), I2: 85.8%; SMD: -0.811 (CI: -1.418, -0.204), I2: 78.8%). There were no significant differences in IF (RD: 0.011 (-0.002, 0.023), I2: 0.0%), PF (RD:0.003 (-0.007, 0.014), I2: 0.0%), and PC (RD:0.001 (-0.008, 0.010), I2: 0.0%). There were significantly higher biological complications (RD: -0.071 (-0.106, -0.036), I2: 0.82.9%) for ST compared to SH in both jaws up to a 10-year follow-up. CONCLUSION: SH and ST had comparable overall outcomes, but short implants had less marginal bone loss and lower biological complications. However, more research is needed to confirm these findings.

Forced Eruption: Alternative Treatment Approach to Restore Teeth with Subgingival Structure.

The management of teeth with deep caries, fracture, or perforation in the cervical third of the root is an integral part of dental practice. Orthodontic extrusion preserves the natural root system and may convert the tooth indicated for extraction into useful tooth with good prognosis and a low risk of failure. Orthodontic tooth eruption can be an alternative to treatment such as surgical crown lengthening, especially in esthetic areas, and provides more favorable conditions for prosthodontic coronal restorations by guaranteeing proper sealing and esthetics and preserving periodontal tissue health. The aim of this case report was to explain a multidisciplinary approach that successfully preserve and treat the teeth with subgingival carious lesion. This innovative method is cost-effective and can be easily done with the equipment available in any office.

Effect of Photobiomodulation Therapy with 915 nm Diode Laser on Pain Perception during Local Anesthesia of Maxillary Incisors: A Randomized Controlled Trial.

This study aimed to evaluate the effect of photobiomodulation therapy (PBMT) with 915 nm wavelength on pain reduction during maxillary incisors' local infiltration in a randomized clinical trial study. A prospective triple-blinded split-mouth clinical trial was designed to assess pain perception during needle insertion and local anesthetic injection in 32 healthy patients required operative caries management on contralateral maxillary incisors. After laser treatment (915 nm, power of 1.5 W, duty cycle of 60% and energy density of 72 J cm^-2 ) in active group and no irradiation in sham group, the injection was performed. Patients' perception of pain was immediately assessed using numerical rating scale (NRS) for pain. Washout period between two appointments was one week. Wilcoxon signed-rank and Pearson correlation statistical analyses were used to assess the comparison of pain score between two appointments and the effect of anxiety level of previous dental injections. The mean scores of pain for the active laser and sham laser groups were 2.5 ± 2.19 and 4.34 ± 2.52, respectively, with a statistically significant higher NRS in the sham laser group (P ˂ 0.05). In this study's condition, diode PBMT reduced pain during infiltration on maxillary incisors. Anxiety experience of dental injection had no significant effect on pain perception scale (P ˃ 0.05).

Canine Rise Method: A Conservative Approach for Worn Teeth Rehabilitation with Different Adhesive Restorative Materials.

Background: In this article, two cases with generalized dental wear and four cases with localized dental wear are reported. In some of the cases, the worn teeth were restored with direct composite techniques with no mock-up and articulator mounting according to the canine rise method. This method is used without any change in the intercuspation of posterior teeth without a muscle relaxation appliance. It introduces a stable occlusal condition that can alter neuromuscular reflex activity, leading to improvements in certain muscle pain disorders. It is also used to protect the teeth and supporting structures from abnormal forces that might create a further breakdown and/or tooth wear. Methods: The first step of treatment in all the cases was a composite build-up for maxillary and mandibular canines to restrict and guide the horizontal and vertical jaw movements and create adequate space for restorations. The second step was the placement of direct or indirect restorations on upper and lower anterior teeth efficiently and accurately. Results: This method enhanced the esthetic outcomes in a conservative approach with no reduction in tooth material or time-consuming treatments. Conclusions: This technique can be suggested for the treatment of worn teeth in patients with Angle's Cl I and Cl II classifications of malocclusion based on the follow-up results. It is not applicable for the treatment of worn teeth in patients with Angle's class III because occlusion is reversed, and canine teeth do not have guidance role. Practical Implications. This method significantly reduces the overall treatment time, and additional steps are required to restore the worn-out teeth and/or occlusion using the canine rise method.

Vickers micro-hardness study of the effect of fluoride mouthwash on two types of CAD/CAM ceramic materials erosion.

BACKGROUND: The aim of this study was to evaluate the protective effects of fluoride mouthwash on the surface micro-hardness of two types of CAD/CAM ceramics after exposure to acidic solutions. METHODS: 40 samples (5 × 5 × 3 mm3) were prepared from two different ceramics: Vitabloc Mark II CAD, and IPS e.max CAD. The samples were randomly divided into 5 groups in each ceramic (n = 8) immersed in different solutions: Gs: saliva: GGA: gastric acid, GAA: acetic acid, GFGA: sodium fluoride + gastric acid, GFAA: sodium fluoride + acetic acid. The microhardness of samples was measured before and after immersion in different solutions by Vickers microhardness tester. By subtracting the microhardness values after and before immersion, the microhardness changes of the samples were obtained. Data were analyzed by Two-way analysis of variance, one-way analysis of variance, and Tukey test (α = 0.05). RESULTS: Immersion in different solutions reduced the microhardness. Microhardness loss was significantly affected in G FAA and G FGA groups in both types of ceramics (P < 0.05). For Vitabloc Mark II groups, the microhardness loss was significantly higher in GFAA and GFGA compared to IPS e.max CAD P < 0.001). CONCLUSION: Fluoride mouthwash in conjunction with acidic solutions may adversely affect microhardness of Vitabloc Mark II CAD, and IPS e.max CAD that may consequently compromise the clinical service. Vitabloc Mark II CAD was significantly more affected than IPS e.max CAD.

Marginal microleakage and modified microtensile bond strength of Activa Bioactive, in comparison with conventional restorative materials.

OBJECTIVES: This study aimed to assess the enamel and dentin marginal microleakage and dentin microtensile bond strength (µTBS) of ACTIVA BioACTIVE Restorative with and without a bonding agent compared with conventional restorative materials. MATERIAL AND METHODS: For enamel and dentin microleakage, Class II boxes were prepared in the mesial (1 mm under the cementoenamel junction) and distal (1 mm above the cementoenamel junction) surfaces of 90 extracted human third molars. The teeth were randomly divided into five groups (n = 18): Group Z (G-Premio Bond + Filtek Z250 XT), Group X (G-Premio Bond + X-tra fil bulk-fill), Group AA (G-Premio Bond + Activa Bioactive restorative), Group A (Activa Bioactive restorative), and Group G (dentin conditioner + Fuji II LC Improve). The teeth were thermocycled, and their microleakage was quantified using the dye penetration test under a stereomicroscope. For dentin µTBS measurement, 12 specimens were fabricated in metal molds (1 × 1 × 12 mm³) for each group mentioned above, and a universal testing machine measured their µTBS. Data were analyzed using one-way analysis of variance (ANOVA), the Kruskal-Wallis test, and multiple comparisons tests. RESULTS: Significant differences were noted among the groups in marginal microleakage and µTBS (p < .001). The highest mean microleakage scores at the enamel and dentin margins were noted in Group A, which had significant differences with other groups (p < .001). The highest µTBS was found in Group X, with significant differences with Group G and Group A (p < .05). The lowest µTBS was noted in Group A, with significant differences with Groups X, Group AA, and Group Z (p < .001). CONCLUSIONS: Activa Bioactive without a bonding agent showed significantly lower µTBS to dentin, and higher microleakage at the enamel and dentin margins. Application of adhesive resin with Activa Bioactive provided a dentine bond strength and marginal seal comparable to other restorative materials.

Comparison of microleakage of an alkasite restorative material, a composite resin and a resin-modified glass ionomer

Aim: To compare the microleakage of Cention N, a subgroup of composite resins with a resin-modified glass ionomer (RMGI) and a composite resin. Methods: Class V cavities were prepared on the buccal and lingual surfaces of 46 extracted human molars. The teeth were randomly assigned to four groups. Group A: Tetric N-Bond etch-and-rinse adhesive and Tetric N-Ceram nanohybrid composite resin, group B: Cention N without adhesive, group C: Cention N with adhesive, and group D: Fuji II LC RMGI. The teeth were thermocycled between 5°-55°C (×10,000). The teeth were coated with two layers of nail vanish except for 1 mm around the restoration margins, and immersed in 2% methylene blue (37°C, 24 h) before buccolingual sectioning to evaluate dye penetration under a stereomicroscope (×20). The data were analyzed by the Kruskal-Wallis and Wilcoxon tests (α=0.05). Results: Type of material and restoration margin had significant effects on the microleakage (p<0.05). Dentin margins showed a higher leakage score in all groups. Cention N and RMGI groups showed significant differences at the enamel margin (p=0.025, p=0.011), and for the latter group the scores were higher. No significant difference was found at the dentin margins between the materials except between Cention N with adhesive and RMGI (p=0.031). Conclusion: Microleakage was evident in all three restorative materials. Cention N groups showed similar microleakage scores to the composite resin and displayed lower microleakage scores compared with RMGI

Comparison the effect of charcoal-containing, hydrogen peroxide-containing, and abrasive whitening toothpastes on color stability of a resin composite; an in vitro study.

BACKGROUND: This study aimed to compare the effects of charcoal-containing, hydrogen peroxide-containing, and abrasive whitening toothpastes on color stability of a resin composite. METHODS: Forty-five specimens were fabricated of spectrum TPH3 composite resin and stored in artificial saliva for 24 h. Baseline color assessment was performed using a spectrophotometer device. Then, the specimens were randomly assigned into 5 experimental groups, namely distilled water (GC), Bencer (GB), colgate optic white (GO), perfect white black (GP) and colgate total whitening (GT) toothpastes. The specimens immersed in coffee solution for 10 min and brushed for 1 min with respective toothpaste and then stored in artificial saliva until the next day. This cycle was repeated for 30 days. After 30 days, the final color assessment was performed using the spectrophotometer. Data were analyzed using one-way ANOVA and Tukey tests. RESULTS: Experimental groups were not significantly different in terms of Δa and ΔE values. However, ΔL and Δb values showed significant difference among the groups. Regarding Δa, GT and GC groups showed red color shift while the other groups showed green color shift. Regarding Δb, all groups showed blue color shift except GT group which showed yellow color shift. CONCLUSION: None of the whitening toothpastes could decrease discoloration caused by the coffee solution to the level below the perceptibility threshold except Colgate Optic White which reduced discoloration within the clinically acceptable perceptibility range.

In Vitro Effect of Acidic Solutions and Sodium Fluoride on Surface Roughness of Two Types of CAD-CAM Dental Ceramics.

OBJECTIVES: This study assessed the effect of immersion in acidic solutions and sodium fluoride on surface roughness of dental ceramics. MATERIALS AND METHODS: 40 blocks of Vitablocs Mark II and IPS e.max CAD (5 × 5 × 3) were prepared. The samples were divided into five groups (n = 8) for immersion in artificial saliva (control), artificially prepared gastric acid, acetic acid, 0.02% sodium fluoride + gastric acid, and 0.02% sodium fluoride + acetic acid. The samples were immersed for 168 hours in the respective solutions except for sodium fluoride, in which the samples were immersed for 69 hours. The surface roughness of samples was measured before and after immersion using a profilometer. The surface roughness changes of three specimens of each group were evaluated by scanning electron microscopy (SEM). Data were analyzed using one-way and two-way ANOVA, Tukey's test, and independent t-test. RESULTS: Significant changes were noted in Ra (P=0.002) and Rq (P < 0.0001) in both types of ceramics. The lowest changes in Ra and Rq parameters were seen in artificial saliva and gastric acid and highest changes occurred following immersion in 0.02% sodium fluoride + acetic acid and 0.02% sodium fluoride + gastric acid, respectively. Changes in Rz were also significant following immersion in Vitablocs Mark II (P < 0.05). Immersion in 0.02% sodium fluoride + gastric acid and 0.02% sodium fluoride + acetic acid produced a rougher surface on both types of ceramics (SEM). CONCLUSION: Exposure of Vitablocs Mark II CAD and IPS e.max CAD to 0.02% sodium fluoride + gastric acid and 0.02% sodium fluoride + acetic acid significantly increased their surface roughness, while for Vitablocs Mark II, lager defects were seen on its surface.

Effect of different surface treatments of presintered or sintered zirconia on bond strength to dentine.

Aim: To compare the effect of different zirconia surface treatments on cement bond strength to dentine. Materials and Methods: Stick-shaped pre-sintered zirconia (N = 128) were prepared and divided into eight groups (n = 16). Three surface treatments (sandblasting, neodymium-doped yttrium aluminum garnet [Nd:YAG] or carbon dioxide laser irradiation) were applied, either before (later to be sintered) or after sintering. The last test group was sintered zirconia coated with feldspathic veneering ceramic. Sintered zirconia without surface treatment was tested as the control group. Zirconia samples were cemented to dentine using Panavia F2 cement. The micro-shear bond strength was measured after 24 h (n = 8) or 10,000 thermocycling (n = 8). Statistical Analysis: Data were analyzed using one-way analysis of variances and Student's t-tests. Results: Zirconia coated with feldspathic ceramic revealed the highest bond strength (P < 0.001). Presintered zirconia treated with Nd: YAG laser showed a significantly improved bond strength compared to the control group before and after thermocycling. The bond strength after thermocycling was significantly reduced in presintered zirconia treated with Nd: YAG or sandblasting. Adhesive failure at the zirconia-cement interface was the dominant failure type. Conclusions: Surface treatment of presintered zirconia by Nd:YAG laser or coating of the sintered specimens with feldspathic veneering ceramic increased the zirconia-cement bond strength.

Efficacy of cavity liners with/without atmospheric cold helium plasma jet for dentin remineralization.

Aim: This study aimed to assess the efficacy of cavity liners with/without the atmospheric cold plasma jet (ACPJ) for dentin remineralization. MATERIAL AND METHODS: The occlusal third of 24 extracted third molars was cut. An occlusal cavity was prepared in the dentin of each tooth with 1 mm depth and 2 mm diameter and demineralized with 37% phosphoric acid for 1 min. The teeth were randomly divided into 8 groups (n = 3). The first control group only underwent demineralization with phosphoric acid. The second control group underwent demineralization and helium plasma jet. Groups 3 to 5 were filled with calcium hydroxide (CH), RetroMTA (MTA) and Biodentine. Groups 6 to 8 were subjected to ACPJ, and all the groups were sealed with polycarboxylate. After 2 weeks of immersion in water, the teeth were longitudinally sectioned and their mineral content was analyzed using energy-dispersive X-ray spectroscopy (EDX). RESULTS: The interaction effect of ACPJ and type of liner was not significant (p > 0.05). Application of ACPJ in combination with liner had a significant effect on calcium and phosphorous contents (p < .05). The calcium and phosphorous contents in the control groups were significantly lower than other groups (p < .05). The calcium and phosphorous contents in the CH group were higher than the control but significantly lower than the MTA and Biodentine groups. The values in the MTA and Biodentine groups were the same and higher than other groups. CONLUSION: All three cavity liners significantly increased the calcium and phosphorous contents of dentin. This increase was significantly greater by the MTA and Biodentine and enhanced by the ACPJ.

Effect of ceramic material type on the fracture load of inlay-retained and full-coverage fixed dental prostheses.

Objective: Ceramic inlay-retained fixed partial denture (IRFPD) is a conservative prosthetic option but the mechanical durability of new high strength zirconia reinforced glass ceramic FPDs is not investigated. The purpose of this study was to compare fracture load of 3-unit ceramic FPDs. Materials and methods: Extracted premolars and molars (N = 64) were used to create three test groups (IRFPDs) and one control group (full coverage FPD) (n = 8). The teeth were embedded in PMMA resin with a mesiodistal distance of 6 mm. Premolars had a distal and molars had a mesial inlay preparation (width: 3 mm; height: 4 mm) in the test groups. IRFPDs were made from a zirconia reinforced lithium silicate (VS) or a monolithic zirconia. Zirconia IRFPDs received 2 types of surface treatments: sandblasting (Zr-IRFPD) or internal coating with feldspathic porcelain (ZrC-IRFPD). Control group was made from monolithic zirconia with the same connector size and zirconia surfaces were sandblasted (Zr-FPD). All restorations were cemented using a resin luting cement. After 5000 thermo-cycles, fracture load values (N) were determined with a universal testing machine at a crosshead speed of 0.75 mm/min. Data were analyzed using 1-way ANOVA and Tukey`s post hoc test (p ˂ .05). Result: Fracture load (mean ± SD) of Zr-FPDs, Zr-IRFPDs and ZrC-IRFPDs were 672 ± 183, 672 ± 123 and 638 ± 59, respectively, being not statistically different (p > .05). VS-IRFPD exhibited statically lower values (391 ± 136). The predominant mode of failure was fracture at the connector area in all groups. Conclusion: The fracture load of 3-unit IRFPD was significantly affected by types of ceramics but the retainer design and surface treatment in Zr groups did not show a significant effect.

Direct Pulp Capping With ProRoot MTA Alone and in Combination With Er:YAG Laser Irradiation: A Clinical Trial.

Background: Due to the complications of root canal treatment, conservative modalities to preserve pulp vitality are favorable. Direct pulp capping (DPC) refers to the coverage of the pulp tissue exposed by a biocompatible agent that can improve the prognosis of the tooth by 44% to 95%. Some recent studies have reported more predictable results (a success rate of about 90%) for DPC with laser and regenerative materials such as mineral trioxide aggregate (MTA). This study aimed to clinically compare DPC with ProRoot MTA alone and in combination with Er:YAG (erbium-doped yttrium aluminium garnet) laser irradiation (2940 nm). Methods: This clinical trial was conducted on 26 patients with a mean age of 29 years (in the range of 17 to 46 years) who required DPC following pulp exposure during deep caries removal. The teeth were divided into two groups. In the control group, the teeth underwent DPC with ProRoot MTA while in the test group, the teeth were first irradiated with a 2940 nm Er:YAG laser and then underwent DPC with ProRoot MTA. The patients were recalled at one, 3 and 6 months for the follow-up (clinical and radiographic examinations). The data were analyzed using Fisher exact test. Results: The success rate was 75% in the laser group and 93% in the control group. The groups were not significantly different (P>0.05). Conclusion: No significant difference was found in terms of the success rate of DPC with ProRoot MTA alone and in combination with Er:YAG laser irradiation.

A 7-Year Follow-up of a Fractured Endodontically Treated Incisor Restored with a One-Piece Post and Core Laminate Veneer.

To achieve natural-appearing aesthetic results and for the conservation of tooth structure, it is important for practitioners to be aware of technological advances in materials science as well as the proper use of aesthetic dental techniques. This clinical report describes the restoration of a left maxillary lateral incisor using a one-piece post and core laminate veneer. This proposed restoration technique represents an alternative to traditional restoration procedures, such as metal-ceramic restorations, all-ceramic crowns, and conventional porcelain laminate veneers. It also conserves the remaining tooth structure, reestablishes function, and offers satisfactory aesthetics with the use of adhesive bonding techniques.

Comparison of microleakage of Scotchbond™ Universal Adhesive with methacrylate resin in Class V restorations by two methods: Swept source optical coherence tomography and dye penetration.

BACKGROUND: One of the most important factors in restoration failure is microleakage at the restoration interface. Furthermore, a new generation of bonding, Scotchbond Universal (multi-mode adhesive), has been introduced to facilitate the bonding steps. The aim of this study was to compare the microleakage of Class V cavities restored using Scotchbond™ Universal with Scotchbond Multi-Purpose in two procedures. MATERIALS AND METHODS: Eighteen freshly extracted human molars were used in this study. Thirty-six standardized Class V cavities were prepared on the buccal and lingual surfaces. The teeth were divided into three groups: (1) Group A: Scotchbond Universal with "self-etching" procedure and nanohybrid composite Filtek Z350. (2) Group B: Scotchbond Universal with "total etching" procedure and Filtek Z350. (3) Group C: Scotchbond Multi-Purpose and Filtek Z350. Microleakage at enamel and dentinal margins was evaluated after thermocycling under 5000 cycles by two methods of microleakage assay: swept source optical coherence tomography (OCT) and dye penetration. Wilcoxon's signed-rank test and Kruskal-Wallis test were used to analyze microleakage. RESULTS: In silver nitrate dye penetration method, group A exhibited the minimum microleakage at dentin margins and group C exhibited the minimum microleakage at enamel margins (P < 0.05). Furthermore, in OCT method, group C demonstrated the minimum microleakage at enamel margins (P = 0.047), with no difference in the microleakage rate at dentin margins. CONCLUSION: Scotchbond Universal with "self-etching" procedure at dentin margin exhibited more acceptable performance compared to the Scotchbond Multi-Purpose with the two methods.

Effect of Intracanal Post Space Treatments on Push-Out Bond Strength of Fiber Posts to Root Dentin.

OBJECTIVES: The main disadvantage of fiber posts is their low bond strength to root canal wall. The aim of the present study was to assess the effect of different root canal post space treatments on push-out bond strength of fiber posts to root canal dentin. MATERIALS AND METHODS: After post space preparation in 40 endodontically treated human premolars, the teeth were randomly divided into four experimental groups: Group 1: control group, group 2: Endsolv R, group 3: ultrasonic cleaning, group 4: Clearfil Repair. Afterwards, the posts were bonded with Panavia F 2.0 bonding cement. The bond strength of fiber posts to root canal wall in the middle part of canal was evaluated following thermocycling using push-out test. Data were analyzed using one-way ANOVA and Tamhane's multiple comparisons test. The failure mode of each group was determined under a stereomicroscope. RESULTS: There was a significant difference in the mean push-out bond strength among the groups (P<0.05). The lowest bond strength was noted in the control group. The control group had significant differences with ultrasonic and Clearfil Repair groups (P<0.05). The bond strength of Endsolv R group increased; however, it was not significant (P>0.05). CONCLUSIONS: It seems that ultrasonic cleaning and Clearfil Repair can modify the root canal wall and significantly increase the bond strength of fiber posts.

Effect of cyclic loading on microleakage of silorane based composite compared with low shrinkage methacrylate-based composites.

BACKGROUND: There are many concerns regarding the marginal seal of composite restorations, especially when composite restorations are subjected to cyclic loading. The aim of this study was to evaluate the effect of cyclic loading on the microleakage of silorane based composite compared with low shrinkage methacrylate-based composites in class V cavities. MATERIALS AND METHODS: In this in vitro study, class V cavities were prepared on the facial and lingual surfaces of 48 human premolars (96 cavities). The teeth were randomly divided into four groups of 12 teeth (24 cavities) each and restored as follows: Group 1 (Siloran System Adhesive + Filtek P90), Group 2 (All Bond SE + Aelite LS Posterior), Group 3 (Futurabond NR + Grandio), and Group 4 (G-Bond + Kalore-GC). All the specimens were thermocycled for 2000 cycles (5-55°C) and then half of the specimens from each group, were Load cycled. All teeth were immersed in 0.5% basic fuchsine dye, sectioned, and observed under a stereomicroscope. Data were analyzed using Wilcoxon test, Kruskal-Wallis, and Mann-Whitney U-tests. P < 0.05 was considered as significant. RESULTS: In both unloaded and loaded groups, no statistically significant differences were observed among four composites at the occlusal margin, but a significant difference in gingival microleakage was found between Aelite and silorane. Occlusal and gingival microleakage was not affected by cyclic loading in none of the four restorative materials. CONCLUSION: Silorane did not provide better marginal seal than the low shrinkage methacrylate-based composites (except Aelite). In addition, cyclic loading did not affect the marginal microleakage of evaluated composite restorations.

Comparison of Dentin Permeability After Tooth Cavity Preparation with Diamond Bur and Er:YAG Laser.

OBJECTIVES: The aim of this study was to compare the permeability of dentin after using diamond bur and Er:YAG laser. MATERIALS AND METHODS: Seventy-two recently extracted, intact, and restoration-free human permanent molars were used in this study. The samples were randomly divided into three groups of 24 each and class I cavities were prepared as follows. Group 1: High speed diamond bur with air and water spray. Group 2: Er:YAG laser. Group 3: Er:YAG laser followed by additional sub-ablative laser treatment. Each group consisted of two subgroups with different cavity depths of 2mm and 4mm. The entire cavity floor was in dentin. Two samples from each subgroup were observed under scanning electron microscope (SEM). The external surfaces of other samples were covered with nail varnish (except the prepared cavity) and immersed in 0.5% methylene blue solution for 48 hours. After irrigation of samples with water, they were sectioned in bucco-lingual direction. Then, the samples were evaluated under a stereomicroscope at ×160 magnification. The data were analyzed using two-way ANOVA and Tukey's HSD test. RESULTS: Two-way ANOVA showed significant difference in permeability between groups 2 and 3 (laser groups with and without further treatment) and group 1 (bur group). The highest permeability was seen in the group 1. There was no significant difference in dentin permeability between groups 2 and 3 and no significant difference was observed between different depths (2mm and 4mm). CONCLUSION: Cavities prepared by laser have less dentin permeability than cavities prepared by diamond bur.