Detection of pit and fissure sealant microleakage using quantitative light-induced fluorescence technology: an in vitro study.

This in vitro study aimed to evaluate the feasibility of quantitative light-induced fluorescence (QLF) technology for detecting the presence and severity of microleakage of pit and fissure sealants. The areas of interest (AOIs) were 160 pits and fissures of 40 extracted permanent teeth. Fluorescent images were acquired using a QLF device, and the maximum fluorescence loss ΔFmax of each AOI was analyzed. After staining and cross-sectioning of the teeth, histological dye penetration was scored on a scale of 0 to 3. The relationship between ΔFmax and microleakage depth was analyzed, and the areas under the curve (AUCs) were calculated. The │ΔFmax│ increased as microleakage depth increased. The ΔFmax values of microleakage areas showed a strong significant correlation with the histological scores of dye penetration (r = - 0.72, P = 0.001). AUC analysis showed a high diagnostic accuracy for microleakage depth (AUC = 0.83-0.91). The highest AUC of 0.91 was found when differentiating the outer half microleakage of the sealant (histological score 0 vs. 1-3). QLF technology is effective in assessing the presence and severity of microleakage, suggesting its potential for noninvasive detection and monitoring of sealant microleakage in clinical settings.

Comparison of push-out bond strength and apical microleakage of different calcium silicate-based cements after using EDTA, chitosan and phytic acid irrigations.

This research was aimed to evaluate push-out bond strength and apical-microleakage after application of three different calcium silicate-based cements with irrigation solutions on simulated immature teeth. 40 maxillary permanent canine teeth were used for push-out bond strength test, and 120 maxillary permanent incisors were used for microleakage evaluation. 120 root slices were divided into four main groups (EDTA, Chitosan, Phytic acid, and Saline) and immersed these solutiouns according to irrigation procedures. Each irrigation group was divided into 3 subgroups (Biodentine, MTA Repair HP, and NeoPUTTY). The prepared teeth were divided into four groups according to irrigation procedure for microleakage test. EDTA irrigation with Biodentine group showed highest push-out bond strength value and saline group with Neoputty showed the lowest push-out bond strength value. The highest microleakage value was seen in saline group with MTA Repair HP, while the lowest microleakage value was observed chitosan with Biodentine group. Chitosan and phytic acid solutions can be recommended as an alternative irrigation solution to 17% EDTA in single-session apexification treatment, since they are non-toxic, naturally occurring materials, effectively remove the smear layer, and have a positive effect on bond strength and apical leakage. RESEARCH HIGHLIGHTS: One of the factors affecting the long-term success of root canal treatment is a hermetic seal. Non-hermetic or inadequate filling triggers a chronic inflammatory reaction in periapical tissues, causing fluids to enter the spaces and negatively affecting the success of the treatment. Therefore, this study will help clinicians choose the right biomaterial and irrigation solution that will affect the success of root canal treatment.

Comparison of Various Commonly Used Luting Cements on the Success of Composite Inlays Assessed by the Levels of the Microleakage-An In vitro Study.

Introduction: Indirect composite restoration is one of the commonly followed procedures in the posterior teeth. The success of this is dependent on many factors, one being the luting cement. Hence, the current study explores the microleakage of the two luting cements at 2 different times. Materials and Methods: Eighty extracted human teeth were taken, and class II cavities were made that were to receive the composite inlays. They were grouped as supragingival and subgingival, which for further divided as were further subdivided to be observed for marginal leakage at cervical and occlusal margins, at the end of a day and 1 month. Each group had ten specimens. The luting cements that were evaluated were Variolink N and RelyX Unicem. After the composite inlay restoration was done for all the specimens, the sections were put on slides, and a stereomicroscope was used to measure the amount of dye penetration. Leakage was evaluated and compared using Mann-Whitney U test. Results: At the end of 1 day, there was no significant alteration in the microleakage in the occlusal or cervical regions for either region supragingivally or subgingivally between the two luting cements. Significant difference between the two cements at the cervical borders at the end of a month was seen for both the margins. When compared supragingivally and subgingivally at the end of 1 day or at the end of 1 month, there was not a significant difference for any of the cements. Conclusion: Within the constraints of the current investigation, it can be said that there was similar microleakage for both Variolink N and RelyX Unicem at the conclusion of a day's storage time. After a 1-month storage period, RelyX Unicem showed more cervical microleakage than Variolink N.

Comparative Evaluation of Different Post and Core Systems in Maxillary Molar Endodontic Treatments: An Original Study.

Background: Maxillary molar endodontic treatments require the right post and core system. This study tested cast metal, glass fiber with composite resin, carbon fiber with composite resin, and zirconia post and core materials. Materials and Methods: Sixty removed human maxillary teeth were randomly divided into four post and core material groups (n = 15 per group). The teeth acquired their post and core system after normal endodontic treatment. Fracture resistance, cyclic fatigue resistance, and microleakage analyses were statistically assessed. Results: The zirconia post and core material had the highest fracture resistance (mean: 900 N), followed by carbon fiber with composite resin, cast metal, and glass fiber with composite resin. Zirconia had the highest mean cycles to failure (120,000), followed by carbon fiber with composite resin (100,000), cast metal (110,000), and glass fiber with composite resin (90,000). Zirconia had the lowest mean microleakage score (1.8), and glass fiber with composite resin, the highest (3.0). Conclusion: The zirconia post and core material outperformed the others in fracture resistance, cyclic fatigue resistance, and sealing. The cast metal has better fracture and cycle fatigue resistance than glass fiber with composite resin. These findings help doctors choose maxillary molar endodontic post and core materials.

Sealing Ability Comparison of Three Different Obturating Systems to Intraradicular Dentin-An In Vitro Stereomicroscopic Study.

Background: Different obturation techniques are being used to improve canal sealing, thereby minimizing marginal leakage. Aims and Objectives: To evaluate the marginal leakage of three different obturating materials and techniques using stereomicroscope. Materials and Methods: Thirty freshly extracted maxillary anterior teeth were collected and were divided into three groups of 10 each for which the biomechanical preparation was done. The teeth were divided into three experimental groups according to the obturation material and technique used, Group I: gutta-percha with AH Plus root canal sealer (lateral condensation): Group II: thermoplasticized gutta-percha technique-non-carrier-based (calamus) with AH Plus sealer (backfill): Group III: C point (self-sealing root canal obturating system) with bioceramic sealer (single cone). Each specimen was subjected for testing apical sealing ability. The values of microleakage associated with different root canal sealers were evaluated using a stereomicroscope. Results: There was no statistically significant difference in the mean scores of apical dye penetration/leakage among all the three groups (P = 0.091), whereas Group I showed a higher degree of apical leakage than the other techniques tested. Conclusion: None of the tested filling materials provided a gap-free or void-free root canal filling; however, thermoplasticized gutta-percha is used with AH Plus sealer exhibited less voids and gaps when compared to other tested materials.

Novel pit and fissure sealant with nano-CaF2 and antibacterial monomer: Fluoride recharge, microleakage, sealing ability and cytotoxicity.

Conventional resin-based sealants release minimal fluoride ions (F) and lack antibacterial activity. The objectives of this study were to: (1) develop a novel bioactive sealant containing calcium fluoride nanoparticles (nCaF2) and antibacterial dimethylaminohexadecyl methacrylate (DMAHDM), and (2) investigate mechanical performance, F recharge and re-release, microleakage, sealing ability and cytotoxicity. Helioseal F served as commercial control. The initial F release from sealant containing 20% nCaF2 was 25-fold that of Helioseal F. After ion exhaustion and recharge, the F re-release from bioactive sealant did not decrease with increasing number of recharge and re-release cycles. Elastic modulus of new bioactive sealant was 44% higher than Helioseal F. The new sealant had excellent sealing, minimal microleakage, and good cytocompatibility. Hence, the nanostructured sealant had substantial and sustained F release and antibacterial activity, good sealing ability and biocompatibility. The novel bioactive nCaF2 sealant is promising to provide long-term F ions for caries prevention.

Influence of etching mode on bonding performance of self-adhesive flowable resin composites to bovine teeth.

This study aimed to evaluate the bonding performance of self-adhesive flowable resin composites (SARs) to bovine teeth. Three SARs, one experimental, and two commercially available products, were used. The study parameters were shear bond strength (SBS), microleakage, and scanning electron microscopy (SEM) evaluation of bonding interfaces. The SBS of the materials was 14.1-15.1 MPa to enamel, 22.2-23.2 MPa to etched enamel, and 7.4-10.7 MPa to dentin. Specimens with pre-etching showed lower microleakage scores than those without pre-etching. SEM images of the interfaces of the materials showed excellent adaptation regardless of the substrate or etching mode. The study results indicate that enamel pre-etching can improve the bonding performance of SARs.

Comparative Evaluation of Luting Efficacy Between a Dual-Cure and Light-Cure Resin Cement on Its Application on Root Surface Indirect Restorations: An In Vitro Study.

Aim The aim is to evaluate the degree of dye penetration between a dual-cure and conventional resin cement on its application on the root surface indirect restorations to provide a reference for clinical choice. Materials and methods Ten freshly extracted human maxillary central anteriors were selected and randomly divided into two groups of five each. Teeth were prepared for veneer restoration, and veneers were luted using two groups of cements Calibra veneer cement and Fusion Ultra D/C cement. After they were immersed in methylene blue dye solution for 24 h, the specimens were then sectioned buccolingual into three halves in a parallel vertical plane and measured dye penetration using a stereomicroscope (Zeiss). The data collected was recorded by the dye penetration index (0-4) and statistically analyzed using the IBM SPSS Statistics for Windows, Version 24 (Released 2016; IBM Corp., Armonk, New York, United States). Results It is evident that group 1 (Calibra veneer cement) showed the lowest mean score of 0.43 mm and group 2 (Fusion Ultra D/C) showed a highest mean score of 0.72 mm. Overall, when the two groups were compared for microleakage using SPSS, there was a significant difference among the groups. Conclusion It was determined that both the resin cements evaluated in this study showed microleakage to some level given the limits of the investigation and the findings. To evaluate the dye penetration of microleakage, the Calibra veneer resin cement showed a better marginal adaptability for veneer restoration. Further investigations with broader methodology and more clinical simulation are needed to evaluate other resin cements available for root surface indirect restorations to be analyzed for prospective clinical outcomes.

Promoting bond durability by a novel fabricated bioactive dentin adhesive.

OBJECTIVE: To prepare a bioactive dentin adhesive and investigate its effect on promoting bonding durability of dentin. METHODS: The mineralization of the bioactive glass with high phosphorus (10.8 mol% P2O5-54.2 mol% SiO2-35 mol% CaO, named PSC) and its ability to induce type I collagen mineralization were observed by SEM and TEM. The Control-Bond and the bioactive dentin adhesive containing 20 wt% PSC particles (PSC-Bond) were prepared, and their degree of conversion (DC), microtensile bond strength (µTBS), film thickness and mineralization performance were evaluated. To evaluate the bonding durability, dentin bonding samples were prepared by Control-Bond and PSC-Bond, and mineralizated in simulated body fluid for 24 h, 3 months, and 6 months. Then, the long-term bond strength and microleakage at the adhesive interface of dentin bonding samples were evaluated by microtensile testing and semiquantitative ELIASA respectively. RESULTS: The PSC showed superior mineralization at 24 h and induced type I collagen mineralization to some extent under weakly alkaline conditions. For PSC-Bond, DC was 62.65 ± 1.20%, µTBS was 39.25 ± 4.24 MPa and film thickness was 17.00 ± 2.61 µm. PSC-Bond also formed hydroxyapatite and maintained good mineralization at the bonding interface. At 24 h, no significant differences in µTBS and interface microleakage were observed between the Control-Bond and PSC-Bond groups. After 6 months of aging, the µTBS was significantly higher and the interface microleakage was significantly lower of PSC-Bond group than those of Control-Bond group. SIGNIFICANCE: PSC-Bond maintained bond strength stability and reduced interface microleakage to some extent, possibly reducing the occurrence of secondary caries, while maintaining long-term effectiveness of adhesive restorations.

In Vitro Microleakage and Fracture Resistance of "Infinity Edge" and Cusp Reduction Preparation Designs for Moderate-sized Class II Composites.

AIM: This study aimed to evaluate the marginal microleakage and maximum occlusal fracture loads and fracture modes of two novel class II preparation designs, "infinity edge" and the "2.5 mm cusp reduction" preparations as compared to a traditional class II preparation without cuspal involvement. MATERIALS AND METHODS: Thirty extracted human mandibular molars were prepared for moderate-sized class II restorations with extensions into all occlusal grooves. Of these, ten class II preparations served as control. Ten were modified for a 2.5 mm even reduction of the cusps adjacent to the interproximal box. An additional 10 preparations were modified with an "infinity edge" bevel on the interproximal and occlusal portions. All teeth were restored utilizing a flowable bulk-fill composite in the apical portion of the interproximal box and 2-4 mm of heated bulk-fill composite in one increment for the remainder. All groups were cyclic loaded and thermocycled, then imaged with microcomputed tomography (µCT) before and after infiltration with a silver nitrate solution. Images were subtracted to obtain volumetric measurements of microleakage and reported as a percentage of the total volume from the apical extent of the proximal box. All groups were loaded to failure and fracture load and mode were recorded. RESULTS: No significant differences were found in microleakage volume as a percentage of total tooth volume; however, the "infinity edge" group had significantly greater microleakage in the proximal box compared to the traditional class II group. No significant differences were found in fracture load or mode between the groups. CONCLUSION: Traditional class II, 2.5 mm cuspal reduction, and "infinity edge" preparation designs have similar fracture loads as well as volumes of microleakage; however, an "infinity edge" preparation has a higher ratio of microleakage in the proximal box. CLINICAL SIGNIFICANCE: Clinicians should carefully consider the use of "infinity edge" margins, particularly on dentin in the apical extent of the proximal box. How to cite this article: Watson JC, Lien W, Raimondi JC, et al. In Vitro Microleakage and Fracture Resistance of "Infinity Edge" and Cusp Reduction Preparation Designs for Moderate-sized Class II Composites. J Contemp Dent Pract 2024;25(1):3-9.

Evaluation of gap formation for different adhesive agents in primary teeth with optical coherence tomography.

Purpose: This study aimed to evaluate gap formation between the tooth surface and restorative material in terms of microleakage by using optical coherence tomography (OCT) for self-etch and selective-etch applications of two different universal and one self-etch adhesives. Materials and methods: Sixty non-caries, primary molar teeth were divided into six groups; self-etch and selective-etch application ways of two different universal and one self-etch adhesive systems (n:10). After Class-V cavities were prepared, every tooth was distributed randomly in groups to apply adhesion procedure and then, all cavities were restored with polyacid-modified composite resin. Microleakage was evaluated by measuring the gap between the tooth surface and restoration by a blind researcher with Image J Software from OCT images. During statistical analysis, the significance level was accepted as p<0.05. Results: According to the statistical analysis of the measurements obtained by Image J Software, selective-etch groups showed less gap formation than self-etch groups for each tested adhesive (p<0.05), and self-etch adhesive without etching showed significantly highest gap formation among all groups (p<0.05). Conclusion: Universal adhesives with a selective-etching step might be preferred over self-etch adhesives for long-lasting polyacid-modified composite resin restorations in primary teeth. However, obtained results should be considered with another prospective clinical study for long-term prognosis.

Bond Strength, Microleakage, Microgaps, and Marginal Adaptation of Self-adhesive Resin Composites to Tooth Substrates with and without Preconditioning with Universal Adhesives.

PURPOSE: This study investigated and compared the bond strengths, microleakage, microgaps, and marginal adaptation of self-adhesive resin composites (SAC) to dentin with or without universal adhesives. MATERIALS AND METHODS: Dentin surfaces of 75 molars were prepared for shear and microtensile bond strength testing (SBS and µTBS). Silicon molds were used to build up direct restorations using the following materials to form 5 groups: 1. Surefil One; 2. Prime&Bond active Universal Adhesive + Surefil One; 3. Vertise Flow; 4. OptiBond Universal + Vertise Flow; 5. Scotchbond Universal + Filtek Z500 (control group). Bonded specimens were thermocycled 10,000x before being tested either for SBS or µTBS using a universal testing machine at a crosshead speed of 0.5 mm/min. Direct mesial and distal class-II cavities were created on 100 sound premolars, with the gingival margin of distal cavities placed below CEJ and restored according to the five groups. After thermocycling, microleakage scores were assessed following immersion of restored premolars in 2% methylene blue dye for 24 h, while marginal gaps and adaptation percentages were investigated on epoxy resin replicas under SEM at magnifications of 2000X and 200X, respectively. Results were statistically analyzed with parametric and non-parametric tests as applicable, with a level of significance set at α = 0.05. RESULTS: Bond strengths, microleakage scores, microgaps, and percent marginal adaptation of Surefil One and Vertise Flow were significantly (p < 0.001) inferior to the control group. Dentin preconditioning with universal adhesives significantly increased the study parameter outcomes of Surefil One and Vertise Flow, yet they were still significantly below the performance of the control group. CONCLUSION: Conventional resin composite outperformed the SAC whether applied solely or in conjunction with their corresponding universal adhesives.

Bacterial Flora in Screw-Fixed Superstructures with Different Sealing Materials: A Comparative Clinical Trial.

A screw-fixed superstructure is predominantly selected for implant prostheses because of the concern regarding developing peri-implantitis, although its infection route remains unclear. Focusing on microleakage from access holes, the present study clinically investigated the bacterial flora in access holes with different sealing materials. We examined 38 sites in 19 patients with two adjacent screw-fixed superstructures. Composite resin was used in the control group, and zinc-containing glass ionomer cement was used in the test group. Bacteria were collected from the access holes 28 days after superstructure placement and were subjected to DNA hybridization analysis. The same patient comparisons of the bacterial counts showed a significant decrease in 14 bacterial species for the red, yellow, and purple complexes in the test group (p < 0.05). In addition, the same patient comparisons of the bacterial ratios showed a significant decrease in six bacterial species for the orange, green, yellow, and purple complexes in the test group (p < 0.05). Furthermore, the same patient comparisons of the implant positivity rates showed a significant decrease in the six bacterial species for the orange, yellow, and purple complexes in the test group. The results of this study indicate that zinc-containing glass ionomer cement is effective as a sealing material for access holes.

Microleakage Under Orthodontic Brackets Bonded Using a Conventional Adhesive System, Nanocomposites, and Nanoionomers: A Comparative Study.

Background Microleakage under orthodontic brackets has a role in early bracket debonding and white spot lesions due to the ingress of oral fluids in the bracket-adhesive-tooth interface. This in vitro study aimed to evaluate and compare the microleakage under orthodontic brackets bonded with the conventional adhesive system, nanocomposites, and nanoionomers. Materials and methods Forty-five human premolars were extracted for therapeutic reasons and collected for this study. Teeth were randomly assigned to three groups: Group A: conventional etching with conventional adhesive, Group B: conventional etching with nanocomposite, and Group C: conventional etching with nanoionomer. Stainless steel premolar brackets were used for bonding. After thermocycling, the extracted teeth were submerged in a 0.5% solution of basic fuchsine for 24 hours. They were then cut longitudinally. A stereomicroscope was used to assess microleakage along the occlusal and gingival interfaces. Results To compare the microleakage scores between gingival and occlusal aspects within each group, the student's t-test was performed. Analysis of variance (ANOVA) and the post-hoc Tukey test were applied to the data for intergroup comparison of microleakage scores. On comparing the microleakage scores, the gingival side of interfaces depicted higher microleakage than the occlusal side gingival side across all groups, demonstrating statistically significant results (P <0.05).On intergroup comparison, the occlusal bracket adhesive interface and gingival tooth adhesive interface revealed significantly higher microleakage values for Group B followed by Group C with Group A the least. However, there was no significant difference in the microleakage scores between Group B and Group C on intergroup comparison of mean microleakage scores (P <0.05). Conclusion The gingival side showed higher microleakage scores than the occlusal side. Nanoionomers showed microleakage values higher than the Transbond XT but lower than nanocomposites. Based on the results of the present study, in terms of microleakage, Transbond XT demonstrated lower microleakage when compared to nanoionomers and nanocomposites.

Effect of silver diamine fluoride on the microleakage of flowable resin composite and glass ionomer cement restorations to carious primary dentin: an-in vitro study.

BACKGROUND: This study aimed to evaluate the effect of Silver Diamine Fluoride (SDF) on the microleakage of flowable resin composite (FRC) and resin-modified glass ionomer cement (GIC) restorations bound to carious primary dentin. METHODS: Forty-four extracted carious primary molars were allocated into four groups as follows (n = 11 teeth/group): Group I, Flowable resin composite (FRCa): SDF38% treatment + FRC, Group II, Flowable resin composite (FRCb): FRC without SDF treatment, Group III, Resin-modified glass ionomer cement (GICa): SDF38% treatment + GIC, Group IV, Resin-modified glass ionomer cement (GICb): GIC without SDF treatment. Specimens were subjected to thermo cycling at 500 cycles between 5 to 55 °C (dwell time of 60 seconds) in baths before being immersed for 24 h in a 1% toluidine blue solution. Microleakage testing was conducted for each specimen in two areas; occlusal and gingival. Specimens were evaluated under stereomicroscope at 4x magnification. Results were analyzed using Kruskal-Wallis test followed by pairwise comparisons utilizing Dunn's post hoc test at p ≤ 0.05. RESULTS: Insignificant differences between different groups (p = 0.49) were observed at the gingival walls area readings. The highest value was found in GICb (2.33 ± 0.52), while the lowest value was found in FRCa (1.71 ± 0.76). Insignificant differences between different groups (p = 0.982) were observed at the occlusal walls area readings. The highest value was found in FRCa (1.43 ± 0.98), while the lowest value was found in GICb (1.17 ± 1.33). CONCLUSION: SDF does not adversely affect the microleakage of FRC and GIC restorations bound to carious primary dentin.

[Influence of cavity design on quality of margin and marginal adaptation and microleakage of all-ceramic CAD/CAM inlays].

OBJECTIVE: To investigate the influence of 135° and 90° cavity design on quality of margin and marginal adaptation and microleakage of all-ceramic computer aided design/computer aided manufacturing (CAD/CAM) inlays. METHODS: One hundred extracted human molars were prepared by criteria of buccal occlusal (BO) inlay. On the buccal, the mesial margin was prepared as 135° bevel while the distal margin was prepared as butt-joint. All-ceramic restorations were made in the Sirona CEREC AC CAD/CAM system with VitaBlocs Mark Ⅱ, Upcera UP.CAD, IPS e.max CAD, Upcera Hyramic and Lava Ultimate. The gaps between each inlay's mesial margin-abutment and distal margin-abutment were recorded under an optical microscope. Each inlay was adhered to the abutment and aged by thermal cycling for 10 000 times. Each specimen was cut into 3 slices after staining. Dye penetration was evaluated under an optical microscope for mesial and distal margins. RESULTS: Mean marginal integrity rate, mean marginal gap value and mean depth of microleakage of 135° margin of Group Upcera Hyramic and Lava Ultimate were significantly better than those of Group VitaBlocs Mark Ⅱ, Upcera UP.CAD and IPS e.max CAD(P < 0.05). Mean marginal gap value, mean depth of microleakage and scale of mean depth of microleakage of 90° margin of Group Upcera Hyramic and Lava Ultimate were significantly better than those of Group Upcera UP.CAD and IPS e.max CAD (P < 0.05) while mean marginal integrity rate was not significantly different (P>0.05). Mean marginal integrity rate of 90° margin was significantly better than that of 135° margin in each group (P < 0.05) while mean depth of microleakage between different margins was not significantly different in each group (P>0.05). Mean marginal gap value of 90° margin of Group VitaBlocs Mark Ⅱ and IPS e.max CAD was significantly better than that of 135° margin (P < 0.05) while there was not significant difference in other 3 groups between 90° and 135° margin (P>0.05). Scale of mean depth of microleakage of 135° margin of Group Upcera Hyramic and Lava Ultimate was significant better than that of 90° margin (P < 0.05) while there was not significantly different in other 3 groups between 90° and 135° margin (P>0.05). CONCLUSION: The mesial and distal margins of abutement of all-ceramic inlay should be prepared as butt-joint.

Evaluation of the effect of high-intensity light-curing device on micro-leakage of pits and fissure sealants.

Reducing treatment time is one of the most important trends in modern dentistry. This study aimed to compare the micro-leakage around the resin sealants when using both high and conventional intensity light-curing systems. The study sample consisted of 30 extracted human maxillary premolar teeth that were divided into two equal groups according to the light-curing system used: Group 1, High-Intensity Light-Curing System and Group 2, Conventional Light-Curing System. Light-curing by Woodpecker I-LED device with two intensities (high and conventional) has been used. All teeth were subjected to 500 cycles of thermocycling. Then, a methylene blue dye microleakage test was performed, and the teeth were sectioned longitudinally and studied under a stereo microscope. The mean of micro-leakage in the high-intensity group (1.33 ± 1.29) was less than in the conventional intensity group (1.63 ± 1.29) without any statistically significant differences (p = 0.320). The high-intensity light-curing system mode may be a good and acceptable alternative to conventional intensity light-curing system mode in polymerization of pits and fissure sealants.

Effects of different removal methods of excess resin adhesive on the microleakage of alumina all-ceramic crowns.

BACKGROUND: Microleakage is a common problem that affects the quality and longevity of all-ceramic crowns. It is influenced by factors such as the resin cement, crown margin design and curing technique. However, few studies focus on the effect of different methods of removing excess resin adhesive on the microleakage of all-ceramic crowns. This study aimed to compare two methods of removing excess resin adhesive (the small brush and sickle methods) on the microleakage of all-ceramic crowns with different marginal clearances. METHODS: Forty extracted third molars were prepared with a 90° shoulder margin and randomly divided into four groups according to their marginal lift (30, 60, 90 or 0 µm). Procera alumina crowns were fabricated using computer-aided design/computer-aided modelling and cemented onto the teeth with 3 M RelyX Unicem (3 M Company, United States) resin cement. Excess resin cement was removed by either the small brush or the sickle scalpel method. The marginal adaptation was observed with a digital microscope. After thermal cycling of the teeth, microleakage was assessed using the dye penetration test under a stereomicroscope. The Mann-Whitney U test and Kruskal-Wallis H test were used to compare the microleakage scores among different groups. RESULTS: The small-brush group showed significantly better marginal adaptation and lower microleakage scores than the sickle group (p < 0.05). There was no significant difference in the microleakage score (grade 0) among different marginal clearances within each group (p > 0.05). CONCLUSION: The small-brush method was more effective than the sickle scalpel method in reducing the microleakage of all-ceramic crowns with different marginal clearances. This method can improve the marginal adaptation and sealability of all-ceramic crowns, thus preventing secondary caries and other complications.

Evaluating the effect of three fissure preparation techniques on microleakage of a colored flowable composite used as a fissure sealant.

Pit and fissure sealants play an essential role in preventive dentistry. This study evaluates the microleakage levels of a new and colored flowable composite applied as a sealant after three preparation techniques. A total of 24 non-carious mandibular permanent molars with deep pits and fissures were included in the study. Pit and fissures were prepared with 37% phosphoric acid, tungsten carbide bur and fissurotomy burs (SS WHITE Dental, New Jersey, USA) using conventional, enameloplasty and fissurotomy techniques. All samples were thermocycled following the placement of Rainbow Flow (PPH CERKAMED Wojciech Pawlowski, Poland) as a sealant and sections were taken after immersion in methylene blue dye. The microleakage levels of the samples were examined under a stereomicroscope (Olympus SZX-7 Olympus SZ-61 Stereo Microscope) at 2.8× magnification to analyze the dye penetration of the flowable composite. The 144 sections were examined and scoring for microleakage was done by examining the dye penetration from the occlusal border to the base of the fissure. Considering all sections regardless of the preparation technique, it was found that 16.6% of the sections have no leakage. Regarding the microleakage scores, the mean score of the conventional group was 1.87 ± 0.98, the mean score of the enameloplasty group was 1.88 ± 1.14, and the mean score of the fissurotomy group was 1.81 ± 1.1. The median scores of the conventional, enameloplasty and fissurotomy groups were 2, 2 and 1.5, respectively. The present study reports no difference between the microleakage level of a colored flowable composite material used as a pit and fissure sealant following three fissure preparation techniques and supports the clinical use of this material.

Effect of protective coating agents on microleakage and flexural strength of glass ionomer cement and zirconomer. an in vitro study.

PURPOSE: The objective of this study was to assess the microleakage and flexural strength of glass ionomer cement (GIC) and modified GIC (Zirconomer) when coated with protective coating agents such as COAT-IT and G-COAT plus. METHODS: Sixty tooth specimens were grouped into two groups based on the type of restorations (GIC (n = 30) and Zirconomer (n = 30)). The samples were further divided into three subgroups (n = 10) based on the protective coating agent (Petroleum jelly, G-COAT Plus, or COAT IT) applied. This study evaluated the microleakage at the occlusal and cervical margins of class V restoration after being subjected to dye penetration and sectioning. Each specimen was viewed under a 40 × microscope and was given scores based on the depth of dye penetration. They were statistically analyzed using the Kruskal-Wallis test and compared within the groups using the Mann- Whitney Test. In addition, flexural strength was assessed using standardized cuboid (25 × 2 × 2 mm) specimens of restorative materials with and without protective coating agents. The mean flexural strength data of all the subgroups were statistically evaluated using a one-way analysis of variance (ANOVA) and compared within the subgroups using the student t test. RESULTS: A statistically significant difference was found when occlusal margin microleakage scores were evaluated with G-COAT Plus demonstrating the lowest occlusal margin microleakage when applied over GIC restoration. The increasing order of occlusal margin microleakage scores is as follows: GIC with G-COAT Plus, Zirconomer with COAT-IT, GIC with COAT-IT, GIC, Zirconomer with G-COAT Plus, and Zirconomer. However, the cervical margin microleakage scores revealed no significant difference. While flexural strength was found to be highest for the GIC group coated with G-COAT Plus, it was observed that there was a significant improvement in the flexural strength of both GIC and Zirconomer when coated with either of the protective coating agents. CONCLUSION: Within the limitations of this in vitro study, it was observed that the application of protective coating agents can significantly reduce the potential microleakage and improve the flexural strength of the restorative material especially when zirconia-reinforced GIC is the restorative material.