Bond Strength and Failure Mode of Glass Fiber Posts with Different Surface Treatments Prior to Silanization: An In Vitro Comparative Study.

Aim: The use of chemical agents in the surface treatment of glass fiber posts can improve their bond strength to the root canal. The aim of this study was to assess the bond strength and failure mode of glass fiber posts that received different surface treatments prior to silanization. Materials and Methods: In this cross-sectional and in vitro experimental study, 50 human lower premolar roots were randomly divided into five groups and subsequently prepared to receive the cementation of a fiberglass post prior to silanization. They were distributed as group 1 (with 24% hydrogen peroxide), group 2 (with 37% phosphoric acid), group 3 (with 1.23% acidulated phosphate fluoride for 2 minutes), group 4 (with 1.23% acidulated phosphate fluoride for 6 minutes), and group 5 (without pretreatment). After cementation, the roots were sectioned into two discs for each cervical, middle, and apical region. Bond strength was assessed using the push out technique. Adhesive, mixed, and cohesive failure modes were also assessed. For data analysis, ANOVA and Tukey's post hoc tests were used, as well as Pearson's chi-square test. A significance of P < 0.05 was considered in all statistical analyses. Results: When comparing the bond strength of root regions, significant differences were obtained in groups pretreated with phosphoric acid (P = 0.018) and acidulated phosphate fluoride for 2 and 6 minutes (P = 0.001 and P = 0.000, respectively). Furthermore, significant differences were obtained between posts treated only with silane and those that received phosphoric acid pretreatment (P = 0.006) and acidulated phosphate fluoride for 6 minutes (P = 0.001). Significant association of mixed failure mode was observed with hydrogen peroxide (P = 0.014) and phosphoric acid (P = 0.006) pretreatments. Cohesive failure was significantly associated with acidulated phosphate fluoride pretreatment for 2 minutes (P = 0.032) and with posts that did not receive treatment prior to silanization (P = 0.000). Conclusion: Posts treated only with silane and pretreated with hydrogen peroxide and acidulated phosphate fluoride for 2 minutes presented significantly higher bond strength with respect to those pretreated with phosphoric acid and acidulated phosphate fluoride for 6 minutes. However, acidulated phosphate fluoride for 2 minutes and silane were associated with a better bonding type.

In vitro controlled elemental analysis to evaluate the combined effect of acidulated phosphate fluoride with Er:YAG and diode lasers.

Background: Acidulated phosphate fluoride (APF) application is used for dental caries prevention. Combining APF with different laser wavelengths increases acid resistance in enamel. Aim: To assess the effects of Er:YAG (2940 nm) laser and diode (940 nm) laser after the application of APF on morphology and mineral content of enamel surfaces of human teeth in vitro. Materials and Methods: Twenty (20) freshly extracted third molar crowns were collected and split longitudinally into halves. Ten (10) halves were given to each of the following groups: group 1 (control), group 2 (application of 1.23% APF gel only), group 3 (diode laser; 1 W for 60 sec, contact mode after APF gel), and group 4 (Er:YAG; 80 mJ, 0.8 W, 10 Hz; in pulsed mode for 10 sec after APF gel). Specimens were morphologically examined by scanning electron microscope (SEM), and mineral content was analysed by energy dispersive X-ray (EDX). Collected data were statistically analysed by ANOVA. Results: Morphologic results were superior in group 3 followed by group 2 and group 1 with the least change in group 4. EDX of calcium (Ca), phosphorous (P), and Ca/P ratio weight % showed the highest value with no statistical significance between groups 2 and 1, and higher with statistical significance in groups 3 and 4 in descending order. Carbon weight % showed highest results in group 4 then 3, 2, and 1. Fluoride weight % showed highest statistical results in group 4 then 2, 3, and 1. Conclusion: The diode laser showed superior morphological results after APF application compared to the Er:YAG laser. The Er:YAG increased fluoride absorption on outer enamel surfaces.

Contexte: L'application de fluorure de phosphate acidulé (FPA) est utilisée pour la prévention des caries dentaires. La combinaison de FPA avec différentes longueurs d'onde de laser augmente la résistance de l'émail aux acides. Objectif: Évaluer les effets du laser erbium YAG (2940 nm) et du laser à diode (940 nm) après l'application de FPA sur la morphologie et le contenu minéral des surfaces de l'émail des dents humaines in vitro. Matériaux et méthodologies: Vingt (20) couronnes de troisième molaire fraîchement extraites ont été recueillies et divisées longitudinalement en moitiés. Dix (10) moitiés ont été données à chacun des groupes suivants : groupe 1 (contrôle), groupe 2 (application de gel de FPA à 1,23 % seulement), groupe 3 (laser à diode; 1 W pendant 60 secondes, mode contact après le gel de FPA), et groupe 4 (erbium YAG; 80 mJ, 0,8 W, 10 Hz kl ; en mode pulsé pendant 10 secondes après le gel de FPA). Les spécimens ont été examinés morphologiquement au microscope électronique à balayage (MEB), et le contenu minéral a été analysé par rayons X à dispersion d'énergie (EDX). Les données recueillies ont été analysées statistiquement par ANOVA. Résultats: Les résultats morphologiques étaient supérieurs dans le groupe 3, suivi par le groupe 2 et le groupe 1, avec le changement le moins important dans le groupe 4. Le pourcentage de l'EDX du calcium (Ca), du phosphore (P) et du rapport Ca/P en poids a montré la valeur la plus élevée sans signification statistique entre les groupes 2 et 1, et la plus élevée avec signification statistique dans les groupes 3 et 4 par ordre décroissant. Le pourcentage en poids de carbone a montré les résultats les plus élevés dans le groupe 4, ensuite 3, 2 et 1. Le pourcentage en poids de fluorure a montré les résultats statistiques les plus élevés dans le groupe 4 puis 2, 3 et 1. Conclusion: Le laser à diode a montré des résultats morphologiques supérieurs après l'application de FPA par rapport au laser erbium YAG. L'erbium YAG a augmenté l'absorption du fluorure sur les surfaces externes de l'émail.

Comparative Fluoride Ion Release Pre and Postrecharge Situations among Three Different Pediatric Dental Restorative Materials: An In Vitro Study.

Objectives: To determine the initial fluoride (F) release and rerelease after recharge of three pediatric dental restorative materials when aged in artificial saliva (M1) and deionized water (M2). Materials and methods: A total of 30 disks, 10 disks of each restorative material R1: Jen Rainbow, Jen Dent Ukraine; R2: Tetric® N-Flow, Ivoclar Vivadent, and R3: resin-modified glass ionomer cement (RMGIC) (Fuji II LC- GC Corporation) were fabricated and were tested for F dynamics in two different media, M1: artificial saliva, M2: deionized water group. The F initial release was measured on the 1st, 7th, 14th, 21st, and 30th day, and on the 31st day, acidulated phosphate F (APF) gel was applied and F rerelease was measured on the 31st, 37th, 44th, 51st, and 60th day using F ion-specific electrode (Orion). The result was statistically analyzed using two-way analysis of variance (ANOVA) and post hoc Bonferroni test. Results: Fluoride (F) ion release was significantly higher in deionized water than in artificial saliva (M1), and F ion rerelease (after recharge) was significantly higher in artificial saliva (M1). Fuji-II LC demonstrated a significantly (p < 0.05) higher F release and rerelease among all the tested materials. Among the tested composites, R2: Tetric® N-Flow exhibited significantly higher F dynamics than R1: Jen Rainbow composite. Conclusion: All the tested restorative materials exhibited optimum F release (0.024 ppm, that is, the range to prevent newer carious lesions) in both the pre and postrecharge conditions. Even though Fuji-II LC demonstrated significantly better F dynamics in the tested scenarios, Tetric® N-Flow has the additional advantage of improved mechanical retentive and esthetic properties along with the optimum F release in pre and postrecharge scenarios. How to cite this article: Mathias MR, Rathi N, Bendgude VD, et al. Comparative Fluoride Ion Release Pre and Postrecharge Situations among Three Different Pediatric Dental Restorative Materials: An In Vitro Study. Int J Clin Pediatr Dent 2022;15(6):729-735.

Fluoride Formed on Enamel by Fluoride Varnish or Gel Application: A Randomized Controlled Clinical Trial.

Although fluoride varnish (FV) and acidulated phosphate fluoride gel (APF-gel) are considered clinically effective to reduce caries, in vitro studies have shown that FV reacts slowly with enamel because most NaF present in the formulation is not solubilized in the FV. Therefore, we conducted a clinical study to evaluate if the time that FV remains on dental surfaces could overcome its slower chemical reactivity when compared with APF-gel. Sixty-eight volunteers were randomly allocated into 4 groups: negative control (Control, no treatment), APF-gel application (1.23% F applied for 4 min), and FV application (Duraphat®, 2.26% F) for 4 h (FV-4h) or 24 h (FV-24 h). To evaluate fluoride formed and retained on enamel, acid biopsies were made on the buccal surfaces of the maxillary central incisors before, at the end of the application of fluoride products (immediately after gel application, or after 4 or 24 h of varnish application), and after 7 and 28 days. Fluoride concentration in dental biofilm was also analyzed before and up to 28 days after initial application. The data were analyzed by 2-way ANOVA, considering treatment and time as factors. The APF-gel and FV-24h groups formed greater fluoride concentration on enamel than the FV-4h and the control group at the end of application (p = 0.0001), with no difference from each other (p = 0.99). The groups did not differ regarding fluoride in biofilm fluid (p = 0.73) and solids (p = 0.40). In conclusion, FV needs to remain in contact with the teeth for prolonged times (>4 h) to reach the same reactivity obtained by a 4-min application of APF-gel.

Gloss and surface roughness of pre-polymerized composite materials designed for posterior CAD/CAM crown restorations corroded with acidulated phosphate fluoride application.

This study assessed the gloss and surface roughness of computer-aided design/computer-aided manufacturing (CAD/CAM) resin composites corroded with acidulated phosphate fluoride (APF) application. One ceramic block, ten CAD/CAM resin composites for premolars, and four CAD/CAM resin composites for molars were assessed. The surface topography of the materials before and after APF application was observed using an electron microscope. The results were analyzed by Wilcoxon signed-rank test and Dunnett's many to one test (p<0.05). Gloss after APF application was significantly lower for all CAD/CAM resin composites except Artesano. Ra after APF application was significantly higher for all CAD/CAM resin composites except Artesano, Dentcraft HR Block, and Estelite P Block, and Sa was significantly higher for all CAD/CAM resin composites. Irregular surface topography was observed after APF application and the surface features differed among the materials. Therefore, APF application may be detrimental to the surface properties of CAD/CAM resin composites.

Effect of Different Preparations of Fluoride Gel on Salivary pH of Albino Rats

Abstract Objective: To evaluate the effect of different preparations of fluoride gels on the salivary pH of albino rats. Material and Methods: This experimental study consisted of 40 Albino rats randomly divided into four equal groups. Group A was the control group and received no intervention. Experimental group B received a topical application of 0.2% sodium fluoride gel. Experimental group C received topical application of stannous fluoride gel 0.4%. Experimental group D received topical application of APF gel (1.23% acidulated phosphate fluoride gel). The different preparations of the gels were applied once daily for 4 minutes on the occlusal surface of the right maxillary molars for 14 days. Salivary pH values were recorded immediately after the application of gels with the help of pH paper on day 1 and day 14. Results: There was a significant difference in the pH level of groups B, C and D after 14 days of fluoride application (p < 0.05). The non-parametric Kruskal Wallis test was applied for the comparison between the groups. Conclusion: This study concluded that all the fluoride gels after administration caused the acidic pH of saliva with the most acidic effect produced by APF gel (AU).

Is professionally applied topical fluoride effective in treating incipient caries? A systematic review

Abstract The present systematic review aimed to investigate the effectiveness of professionally applied topical fluoride as therapeutic agent for incipient carious lesions in permanent teeth. Randomised clinical trials (RCTs) comparing the effectiveness of professionally applied topical fluoride (varnish or gel) with that of placebo, no intervention, and toothbrushing (control group) in the treatment of incipient carious lesions in permanent dentition were included. An electronic search was performed in the PubMed, Web of Science, Scopus, Virtual Health Library, Embase, and Cochrane databases, in the grey literature, and in clinical trials registered until January 2021. Two reviewers independently screened titles and abstracts and assessed the risk of bias using the Cochrane tool. The certainty of evidence was classified using GRADE. A total of 2,223 articles were screened using titles/abstracts. After full-text reading of the 22 selected studies, nine RCTs were included. Five RCTs found that topical fluoride may be effective in reversing incipient carious lesions in permanent teeth. Overall, five studies were classified as having a low risk of bias and four as having some concerns. Only descriptive analysis was performed because of the heterogeneity of the data. Studies comparing fluoride varnish with usual home care oral hygiene have demonstrated topical fluoride does not appear to be more effective in improving the appearance of incipient carious lesions. Therefore, usual home care oral hygiene with fluoride toothpaste may be sufficient to treat incipient carious lesions in permanent dentition. Further studies with greater methodological rigor are, however, required to reduce bias, to allow a meta-analysis, and to draw well-founded conclusions (CRD42019120406).

The effect of Remin Pro on the microhardness of initial enamel lesions in primary teeth: An in vitro study.

BACKGROUND: Remineralization is currently considered a treatment option for many clinicians. The present study was conducted to compare the effect of three remineralizing agents on microhardness of initial caries lesions in primary teeth. MATERIALS AND METHODS: In this in vitro study, 96 enamel samples were prepared. Microhardness was first measured for all the samples using the Vickers microhardness test. After developing the initial caries lesions, the microhardness of all the demineralized samples was measured, and the samples were then divided into four groups (n = 24). Casein phosphopeptide-amorphous calcium phosphate in Group 1, Remin Pro in Group 2, and acidulated phosphate fluoride gel in Group 3 were placed on the samples for 4 min. The control group received no treatments. The microhardness of the samples was measured again following a pH cycle of 5 days. The data were analyzed by ANOVA and the post hoc test at the significance level of P < 0.05. RESULTS: The mean microhardness reduced significantly in all the groups following the development of initial caries lesions and after the pH cycle of 3 days (P < 0.001). After the remineralization and pH cycle of 5 days, the mean microhardness was significantly lower in the control group compared to the other three groups (P < 0.001) and had increased in the three treated groups. The microhardness recovery rate also increased in the treated groups compared to the control group, but no significant differences were observed between the three groups themselves (P > 0.05). CONCLUSION: Remin Pro can be used as an effective substance for preventing tooth caries in children.

Time-dependent effects after enamel fluoride application on an acid etching system in orthodontic bracket bonding.

OBJECTIVES: This study investigated the effectiveness of acid etching and bond strength in an orthodontic bonding system in accordance with various time periods after 1.23% acidulated phosphate fluoride (APF) gel applications. MATERIALS AND METHODS: APF gel was applied on the enamel surface of bovine teeth, which were assigned to group F0. The tooth specimens were then immersed in distilled water for 1 (F1), 7 (F7), 14 (F14), 21 (F21) and 28 (F28) days. A group without fluoride pretreatment was a control group. All groups were etched with 35% phosphoric acid and evaluated using a surface hardness tester and scanning electron microscope (SEM). A shear bond strength (SBS) test was performed using a universal testing machine, and the bond failure modes were also examined. RESULTS: After the 1.23% APF gel treatment, the hardness of the acid-etched enamel surface decreased as the immersion period increased. SEM images of the test groups showed etched patterns similar to control group as the immersion period increased. The SBS increased with increasing immersion period, whereas group F21 was not significantly different from the control group. Relatively high adhesive remnant index scores were identified as the ageing period increased. CONCLUSIONS: The present study indicated that in order to obtain suitable bond strength, it is recommended to use an acid etching-based bonding system for the fixation of orthodontic appliances on the enamel surface 21 days after the use of APF gel. CLINICAL RELEVANCE: Fluoride pre-treatment interferes with the acid etching effects on enamel, causing a reduction in the bond strength with orthodontic brackets.

Efficacy of 1. 23% acidulated phosphate fluoride gel on non-cavitated enamel lesions: a randomized clinical trial

Abstract: A randomized controlled parallel clinical trial was conducted to evaluate the efficacy of the association of 1.23% topical professional acidulated phosphate fluoride (APF) gel with oral hygiene and dietary instructions on the arrest of active non-cavitated lesions in permanent, mixed, and temporary dentition in children between 3 and 12 years of age. Ninety-eight caries-active children were randomly divided into two groups: a fluoride gel group (n = 49) and a non-fluoridated gel group (n = 49). Each group received up to eight weekly applications of gel, weekly professional toothbrushing with oral hygiene instructions and dietary counselling. Caries lesions were assessed qualitatively through visual-tactile criteria performed in three stages: initial, intermediate, and final. Regression models were applied to identify risk indicators for caries control. Between-group comparison regarding the time taken to arrest the lesions was performed using Chi-squared and Fisher's exact tests. Seventeen children did not receive the allocated intervention, and one was lost to follow-up (n = 80). There was no difference between the control and placebo groups regarding the time to the arrest of the lesion (p >.05). The treatments showed similar results without significant statistical difference (p = 0.33; 95%CI: 0.32-1.48). No adverse effects were observed. It can be concluded that no additional effect of the association of 1.23% APF gel with oral hygiene using fluoride dentifrice and dietary instructions on the arrest of active non-cavitated lesions could be established. We can also confirm the importance of toothbrushing frequency and, consequently, the visible plaque reduction in the control of caries activity. RBR-37V5S3

Evaluation of diode laser along with 1.23% acidulated phosphate fluoride gel on dentinal tubule occlusion: An in vitro study.

CONTEXT: Several studies have recommended the use of lasers in treatment of dentinal hypersensitivity. These materials have been used alone or in combination with an active desensitizing agent. AIMS: The present study aimed to evaluate the use of 1.23% acidulated phosphate fluoride (APF) gel and 810 nm diode laser when used alone and when used together on exposed dentinal tubules. SETTINGS AND DESIGN: Sixty-one extracted teeth were sectioned with a diamond saw and dentin slices were prepared. They were then treated with 37% orthophosphoric acid to remove the smear layer. MATERIALS AND METHODS: One of the 61 sections was left as an untreated control, whereas the remaining sixty sections were divided into three groups of twenty sections each. The first set of sections (Group 1) was treated with laser alone, whereas the second set (Group 2) was treated with APF alone. A third set of sections (Group 3) was treated with a combination of laser and APF. The sectioned teeth were then evaluated using field emission scanning electron microscopy, and the percentage of dentinal tubule occlusion was observed. STATISTICAL ANALYSIS: The Shapiro-Wilk normality test was performed to check for the normal distribution of data, whereas the Kruskal-Wallis test was used to compare the mean percentage of dentinal tubule occlusion between the three groups. The Chi-square test was used to compare the number of images with complete tubular occlusion between the three groups. RESULTS: A total of 96 images were processed from the sixty sectioned samples. It was seen that the sections in Group 3 showed the highest percentage of dentinal tubule occlusion. Group 3 also showed the highest number of samples with complete dentinal tubule occlusion. Significantly lesser levels of dentinal tubule occlusion were seen in Groups 1 and 2. CONCLUSIONS: Diode lasers were effective in occluding dentinal tubules. The addition of 1.23% APF significantly increased the efficacy and thoroughness of dentinal tubule occlusion. Significantly lesser levels of dentinal tubule occlusion were seen in the sections treated with laser alone and APF alone.

Microshear Bond Strength of Composite Resin to Enamel Treated With Titanium Tetrafluoride and the Carbon Dioxide Laser (10.6 µm): An In Vitro Study.

Introduction: The present study aims to assess the microshear bond strength (µSBS) of composite to enamel treated with titanium tetrafluoride (TiF4 ) and CO2 laser irradiation. Methods: Fifteen human molars were sectioned and their enamel surfaces were abraded. The sections were randomly assigned to 5 groups (n=15): (CO); control group, (AP); treated with 1.23% acidulated phosphate fluoride (APF) for 4 minutes, (Ti); 4% TiF4 for 1 minute, (L+AP); CO2 laser irradiation (10.6 µm wavelength, 1 W peak power, 10 ms pulse duration, 500 ms repetition time, 0.2 mm beam spot size at the tissue level, 2 cm distance of handpiece tip to tissue surface (DSE, South Cores) followed by 1.23% APF, and (L+ Ti); 10.6µm CO2 laser irradiation followed by 4% TiF4 for one minute. Using Tygon tubes, Z250 (3M/ESPE) composite was bonded to the surface of the samples. The µSBS of composite to enamel was measured using a microtensile testing machine after 500 thermal cycles. The data were analyzed by one-way ANOVA and the Tukey HSD test (P <0.05). Results: The mean µSBS was 20.66, 20.21, 13.44, 23.01, and 10.16 MPa in CO, AP, Ti, L+AP, and L+Ti groups respectively. Significant differences were observed between CO and Ti (P =0.026) and also CO and L+ Ti (P <0.0001). Conclusion: The application of TiF4 per se and after CO2 laser irradiation on enamel decreased the µSBS of composite to enamel; on the other hand, APF alone and after laser irradiation did not have any adverse effect on the µSBS of composite to enamel.

Effect of CO2 Laser and 1.23% Acidulated Phosphate Fluoride on Acid Resistance and Fluoride Uptake of Human Tooth Enamel: An In Vitro Assessment.

AIM: To evaluate the effectiveness of CO2 laser treatment before applying 1.23% acidulated phosphate fluoride (APF), through topically applied 1.23% APF solution, and after applying 1.23% APF on acid resistance and fluoride uptake of the enamel. MATERIALS AND METHODS: Sixty non-carious human premolars were extracted due to the orthodontic reason and stored in distilled water solution under refrigeration. Using a water-cooled diamond disc, enamel slabs of 4 mm × 4 mm × 1.5 mm were cut from the buccal surface of each tooth. Sixty samples were randomly divided into one control group and five test groups of 10 premolars each. Solution was prepared for wet chemical analysis followed by fluoride analysis that was carried out using a fluoride ion selective electrode (Thermo Scientific Orion 4-Star Plus ISE Meter). The weight of enamel (WE) was determined from the amount of calcium (Ca) etched away considering the fact that the Ca content of the human enamel is 37.4 wt%. The subgroups were statistically analyzed using ANOVA for fluoride determination and evaluation of acid resistance. RESULTS: There was a significant increase in acid resistance of enamel slabs when treated individually or in combination of a low-power CO2 laser and 1.23% APF solution. Application of 1.23% APF solution after low-power CO2 laser treatment showed maximum increase in acid resistance. CONCLUSION: Application of a low-power pulsed CO2 laser through topically applied 1.23% APF solution resulted in a detrimental effect of the human tooth enamel with resultant decrease in acid resistance. High fluoride uptake does not necessarily indicate increased acid resistance. CLINICAL SIGNIFICANCE: The present study provides evidence that a low-power CO2 laser can be used effectively in combination with topically applied 1.23% APF solution in order to make the enamel more resistant to acid attack, thereby helping in controlling dental caries.

The Effect of Titanium Tetrafluoride Treatment and the CO2 Laser on Acid Resistance of Human Enamel.

Introduction: Titanium tetrafluoride (TiF4 ) is deemed more effective than the previous fluoride compounds. To enhance the effect of the fluoride compounds, researchers have suggested their association with lasers, although there are conflicting results in this area. We evaluated the acid resistance of enamel after treatment with the CO2 laser and TiF4 . Methods: Thirteen human premolar teeth were sectioned into 5 parts and each segment was assigned to a study group: co (control): without treatment, AF: enamel treatment with APF 1.23% for 4 minutes, TF: enamel treatment with TiF4 4% for 1 minute, TF-L: enamel treatment with TiF4 4% and then the CO2 laser (Peak power: 1 W, pulse duration: 10 ms, interval time: 500 ms, Beam spot size: 0.2 mm, distance: 2 cm), L-TF: enamel treatment with the CO2 laser and then TiF4 4%. Each sample was kept for 7 days in acidic solution of hydroxyethyl cellulose at pH=4.5, and the amount of the calcium ion released in the solution was measured by atomic absorption spectrometry. Data were analyzed by ANOVA and Bonferroni tests. The significance level was set at 0.05. Results: The average concentration of the calcium ion released in acidic solution was 197.46, 153.30, 99.23, 61.23, 55.46 ppm in the groups respectively. There was a significant difference between the study groups (P<0.0001). Only the difference between TF-L and L-TF was not significant (P>0.05). Conclusion: The loss of calcium from the enamel samples in the groups treated with a combination of the laser and TiF4 was significantly lower than the groups treated with fluoride alone, or the control group. It did not make a significant difference whether the CO2 laser was applied before or after TiF4 .

Comparative evaluation of fluoride release and recharge potential of novel and traditional fluoride-releasing restorative materials: An in vitro study.

AIM: The aim of this study was to evaluate and compare the fluoride ion release and uptake of glass ionomer cement GP IX Extra (GE), EQUIA® Forte Fil (EF), Beautifil Bulk (BB), Dyract® XP (DXP), Tetric N-Ceram® (TNC) in vitro. MATERIALS AND METHODS: The restorative materials were divided into five groups (n = 12), namely G1 - GE, G2 - EF, G3 - BB, G4 - DXP, G5 - TNC. Fluoride release was checked using fluoride ion-selective electrode (Orion 9609BNWP, Ionplus Sure-Flow Fluoride, Thermo Scientific, USA) at time intervals of 1 day and thereafter at 3, 7, 14, 21, and 28 days. Following this, fluoride recharge was done with 1.23% acidulated phosphate fluoride gel (12,300 ppm, Pascal International Inc., 2929 Northup Way, Bellevue, USA) after 28 days and each sample was re-checked for fluoride release at the same time intervals. STATISTICAL ANALYSIS: One-way ANOVA with post hoc Games-Howell test for intergroup and repeated measures ANOVA with post hoc Bonferroni test for intragroup analysis. P < 0.05 was considered statistically significant. RESULTS: On intergroup analysis, Group 2 showed high values of fluoride release and recharge at all-time intervals which were significantly higher (P < 0.001) than Groups 1, 3, 4 and 5. Intragroup analysis showed significantly higher (P < 0.001) fluoride release and recharge at the end of day 1 which decreased progressively with time for all the tested materials. CONCLUSION: EF showed the highest fluoride release and recharge potential across all time intervals compared to other tested restorative materials and the greatest fluoride release was seen on day 1.

Effect of different clinical applications on physico-mechanical properties of composite resins / Efeito de diferentes aplicações clínicas nas propriedades físico-mecânicas de resinas compostas

Although clinicians use fluoride agents to reduce the occurrence of caries, and surface sealing agents to protect composite restorations, the effects of these agents on composite resins have not yet been investigated. The goal of this study was to determine the effect of different surface applications (fluoride or surface sealant) on resin composites with different organic structures (Siloranes, Sonicfill, 3M Z550, Kalore). In this study, 120 discs and 120 bars made of composite resin were stored in water for three months before being thermally aged by cycling between 5°C and 55°C for 10,000 cycles. The discs were 15 mm in diameter and 1 mm thick; the bars were 25 × 2 × 2 mm. The surface sealant and fluoride were applied to the specimens, and evaluations were performed after 24h. Initial and final calculations were performed for flexural strength, microhardness, roughness, gloss, water sorption, and solubility. Silorane composite showed the lowest water sorption levels (p < 0.05) for both initial and aged groups. Silorane and SonicFill composite groups showed the lowest solubility (p < 0.05). Both before and after aging, the SonicFill group showed the highest values of flexural strength and microhardness. Silorane showed the highest roughness and lowest gloss values. Lower water sorption and solubility rates were seen on materials fabricated from hydrophobic monomers. High water sorption and solubility degrades the mechanical and surface properties. Fluoridation and surface sealant application can alter the surface properties but do not have any effect on the mechanical properties.

Embora os clínicos utilizem agentes de flúor para reduzir a ocorrência de cáries e agentes de vedação de superfície para proteger restaurações compostas, os efeitos desses agentes sobre as resinas compostas ainda não foram investigados. O objetivo deste estudo foi determinar o efeito de diferentes aplicações de superfície (fluoreto ou selante de superfície) em resinas compostas com diferentes estruturas orgânicas (Siloranes, Sonicfill, 3M Z550, Kalore). Neste estudo, 120 discos e 120 barras de resina composta foram armazenados em água por três meses antes de serem envelhecidos termicamente por ciclos alternados entre 5 °C e 55 °C por 10.000 ciclos. Os discos tinham 15 mm de diâmetro e 1 mm de espessura; as barras eram 25 × 2 × 2 mm. O selante de superfície e o flúor foram aplicados nos espécimes e as avaliações foram realizadas após 24 horas. Cálculos iniciais e finais foram realizados para resistência à flexão, microdureza, rugosidade, brilho, sorção de água e solubilidade. O compósito de silorano apresentou os menores níveis de sorção de água (p <0,05) para os grupos inicial e envelhecido. Os grupos compostos Silorane e SonicFill apresentaram a menor solubilidade (p <0,05). Tanto antes quanto depois do envelhecimento, o grupo SonicFill apresentou os maiores valores de resistência à flexão e microdureza. Silorane apresentou a maior rugosidade e menores valores de brilho. Baixas taxas de sorção e solubilidade da água foram observadas em materiais fabricados a partir de monômeros hidrofóbicos. A alta sorção e solubilidade da água degrada as propriedades mecânicas e de superfície. A fluoretação e a aplicação de selante de superfície podem alterar as propriedades da superfície, mas não afetam as propriedades mecânicas.

Acid Etching as Surface Treatment Method for Luting of Glass-Ceramic Restorations, part 1: Acids, Application Protocol and Etching Effectiveness.

AIM: The purpose of this review is to represent acids that can be used as surface etchant before adhesive luting of ceramic restorations, placement of orthodontic brackets or repair of chipped porcelain restorations. Chemical reactions, application protocol, and etching effect are presented as well. STUDY SELECTION: Available scientific articles published in PubMed and Scopus literature databases, scientific reports and manufacturers' instructions and product information from internet websites, written in English, using following search terms: "acid etching, ceramic surface treatment, hydrofluoric acid, acidulated phosphate fluoride, ammonium hydrogen bifluoride", have been reviewed. RESULTS: There are several acids with fluoride ion in their composition that can be used as ceramic surface etchants. The etching effect depends on the acid type and its concentration, etching time, as well as ceramic type. The most effective etching pattern is achieved when using hydrofluoric acid; the numerous micropores and channels of different sizes, honeycomb-like appearance, extruded crystals or scattered irregular ceramic particles, depending on the ceramic type, have been detected on the etched surfaces. CONCLUSION: Acid etching of the bonding surface of glass - ceramic restorations is considered as the most effective treatment method that provides a reliable bond with composite cement. Selective removing of the glassy matrix of silicate ceramics results in a micromorphological three-dimensional porous surface that allows micromechanical interlocking of the luting composite.

Comparison of enamel remineralization potential after application of titanium tetra fluoride and carbon dioxide laser.

BACKGROUND AND AIMS: The aim was comparison of enamel remineralization after application of APF, TiF4 and CO2 laser alone or in combination. MATERIALS AND METHODS: Enamel blocks were prepared from human third molars. The initial surface hardness was determined by Vicker's hardness tester. The samples underwent a demineralization regimen for 7 days to produce artificial initial caries. The hardness of enamel blocks with white spot lesions was measured, and the samples which had the mean hardness change of 65-90%, were selected, and randomly divided into 5 groups (N=15): G1: control; G2: APF 1.23%; G3: TiF4 4%; G4: TiF4 4% followed by CO2 laser (10.6 µm wavelength, 1 W peak power, 10 ms pulse duration, 500 ms repeat time, 0.2 mm beam spot size, 2 cm distance); G5: CO2 laser (same parameters) followed by TiF4 4%. Surface hardness recovery was measured after the treatments. Three samples in each group were observed under scanning electron microscope at ×1,000 magnification. Data were analyzed by repeated measure ANOVA and Bonferrouni tests. Significance level was set at 0.05. RESULTS: G2, G3, G4 indicated significant differences with control and G5 (p<0.05). Surface hardness in G5 was not significantly different from control (p=0.7) in enamel hardness test. There was not a significant difference between G2 & G3, G2 & G4, and G3 & G4 (p=1). The SEM results indicated globules of calcium fluoride on the surface in G2, and a smooth glaze-like surface layer in G3 and G4. In G5, some micro-cracks without any glaze-like layer were observed. CONCLUSIONS: APF, TiF4 and TiF4 before CO2 laser irradiation significantly increased the micro-hardness of initially demineralized enamel surfaces. CO2 laser irradiation before TiF4 application could not remineralize the white-spot lesions.

Influence of resin-modified glass ionomer and topical fluoride on levels of Streptococcus mutans in saliva and biofilm adjacent to metallic brackets

Abstract Decalcification of enamel during fixed orthodontic appliance treatment remains a problem. White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. The use of fluoride-containing orthodontic materials has shown inconclusive results on their ability to reduce decalcification. The aims of this investigation were to compare the levels of Streptococcus mutans (SM) in saliva and biofilm adjacent to orthodontic brackets retained with a resin-modified glass ionomer cement (RMGIC) (Fuji ORTHO LC) and a light cured composite resin (Transbond XT), and to analyze the influence of topical application of the 1.23% acidulated phosphate fluoride (APF) on SM counts. In a parallel study design, two groups (n=14/15) were used with random allocation and high salivary SM counts before treatment. Biofilm was collected from areas adjacent to the brackets on teeth 13, 22, 33, and 41. Both saliva and biofilm were collected on the 7th, 21st, 35th, and 49th days after appliance placement. Topical fluoride application was carried out on the 35th day. Bonding with RMGIC did not alter SM counts in saliva or biofilm adjacent to the brackets. On the other hand, the biofilm adjacent to brackets retained with composite resin showed a significant increase in SM counts along the trial period. Topical application of 1.23% APF did not reduce salivary or biofilm SM counts regardless of the bonding material. In conclusion, fluoride topical application did not show efficacy in reducing SM. The use of RMGIC as bonding materials allowed a better control of SM cfu counts in dental biofilm hindering the significant increase of these microorganisms along the trial period, which was observed in the biofilm adjacent to the composite material.

Effect of 5,000 ppm Fluoride Dentifrice or 1,100 ppm Fluoride Dentifrice Combined with Acidulated Phosphate Fluoride on Caries Lesion Inhibition and Repair.

High fluoride dentifrice (FD; 5,000 ppm F) has been recommended to arrest root dentine lesions and to control enamel caries in high-risk patients. Also, standard FD (1,100 ppm F) in combination with professional fluoride application has been recommended to control dentine caries, but the effect of this combination on enamel has been considered modest. Considering the lack of evaluation comparing the use of 5,000 ppm FD (5,000-FD) versus acidulated phosphate fluoride (APF) application combined with 1,100 ppm FD (1,100-FD) on the inhibition and repair of caries lesions in both enamel and dentine, we conducted this in situ, double-blind, crossover study of 3 phases of 14 days. In each phase, 18 volunteers wore palatal appliances containing enamel and root dentine specimens, either sound or carious, to evaluate the effect of the treatments on the inhibition or repair of caries lesions, respectively. The treatments were non-FD (negative control), 5,000-FD, or 1 APF gel application on dental specimens combined with 1,100-FD used twice per day (APF + 1,100-FD). The reduction of demineralization and enhancement of remineralization were assessed by surface and cross-sectional hardness. Fluoride concentration was determined on dental specimens and on the formed biofilm. For enamel, APF + 1,100-FD and 5,000-FD did not differ regarding the inhibition of demineralization and repair of caries lesions. However, for dentine the difference between these treatments was inconclusive because while APF + 1,100-FD was more effective than 5,000-FD in caries lesion reduction and repair, 5,000-FD was more effective than APF + 1,100-FD in the reduction of surface demineralization. Therefore, the findings show that the combination of APF + 1,100-FD is as effective as 5,000-FD in enamel inhibition of demineralization and enhancement of remineralization.