Engineering an Autonucleolytic Mammalian Suspension Host Cell Line to Reduce DNA Impurity Levels in Serum-Free Lentiviral Process Streams.

We engineered HEK293T cells with a transgene encoding tetracycline-inducible expression of a Staphylococcus aureus nuclease incorporating a translocation signal. We adapted the unmodified and nuclease-engineered cell lines to grow in suspension in serum-free media, generating the HEK293TS and NuPro-2S cell lines, respectively. Transient transfection yielded 1.19 × 106 lentiviral transducing units per milliliter (TU/mL) from NuPro-2S cells and 1.45 × 106 TU/mL from HEK293TS cells. DNA ladder disappearance revealed medium-resident nuclease activity arising from NuPro-2S cells in a tetracycline-inducible manner. DNA impurity levels in lentiviral material arising from NuPro-2S and HEK293TS cells were undetectable by SYBR Safe agarose gel staining. Direct measurement by PicoGreen reagent revealed DNA to be present at 636 ng/mL in lentiviral material from HEK293TS cells, an impurity level reduced by 89% to 70 ng/mL in lentiviral material from NuPro-2S cells. This reduction was comparable to the 23 ng/mL achieved by treating HEK293TS-derived lentiviral material with 50 units/mL Benzonase.

An Alternative Technique for Topical Application of Acidulated Phosphate Fluoride (APF) Gel: A Two-Years Double-Blind Randomization Clinical Trial (RCT).

Background and Objectives: Dental caries is still a dramatic public health problem. The effectiveness of an alternative technique using acidulated phosphate fluoride (APF) gel pH 3.5 was evaluated and compared with conventional treatments in reducing dental caries incidence. Materials and Methods: A double-blind randomized controlled trial was conducted, involving 180 children aged 4-11 years. Three groups were formed: NaF varnish (NaFV), APF in tray (APFt), and APF in toothbrush (APFtbru). Clinical examinations were performed using standardized criteria and the ICDAS Index was assessed. The Caries Treatment Needs Index (CTNI) was calculated. Dental examinations were conducted at baseline, 12 months, and 24 months. Results: At baseline, 16,719 dental surfaces were included, with 15,434 surfaces being sound. After 24 months, the Kaplan-Meier analysis showed significant differences between the APFtbru group and the other two groups (p = 0.03). Cox regression analysis revealed that the surfaces treated with NaF varnish had the lowest survival rates (HR = 0.51 95%CI = 0.33/0.81). Occlusal surfaces had the lowest cumulative survival, while other tooth surfaces showed similar performance. Conclusions: The alternative technique of APF gel application with a toothbrush resulted in maintaining dental health over 24 months. This technique can be cost-effective and may offer advantages over traditional fluoride varnish application.

CO2 laser irradiation combined with fluoridated dentifrice improved its protective effect on caries lesion progression regardless of the acidulated phosphate fluoride gel application: An in situ study.

OBJECTIVE: This in situ study aimed to investigate the efficacy of CO2 laser at a 10.6-µm wavelength combined with 1.23% acidulated phosphate fluoride (APF) and fluoridated dentifrice with 1100 µg F/g (FD) to control enamel caries progression. MATERIALS AND METHODS: Sixteen volunteers wore palatal appliances containing eight demineralized enamel specimens for four 14-day phases under sucrose exposure. These specimens were submitted to CO2 laser irradiation and APF alone or combined with FD. Treatment groups were non-fluoridated dentifrice-NFD, NFD + CO2 laser, NFD + APF, NFD + CO2 laser + APF, FD, FD + CO2 laser, FD + APF, and FD + CO2 laser + APF. Mineral loss, calcium fluoride (CaF2), fluorapatite (FAp), and fluoride in the biofilm were analyzed by analysis of variance followed by the Student-Newman-Keuls test, p < 0.05. RESULTS: The highest mineral loss inhibition was noted when FD and CO2 laser irradiation were combined, which did not significantly differ from the FD + CO2 laser + APF group. The CaF2, FAp, and F in the biofilm were more pronounced when the FD and APF were combined. The CO2 laser irradiation promoted a slightly higher concentration of CaF2 in the enamel and F in the biofilm. CONCLUSION: Although APF promotes the high formation of CaF2 and FAp, the combined use of FD with CO2 laser overcomes the APF effect in inhibiting the progression of artificial caries-like lesions in situ. CLINICAL SIGNIFICANCE: Under the in situ design of this study, remineralization of white spot lesions was achieved through CO2 laser irradiation and daily use of fluoridated dentifrice. Future clinical trials are encouraged to substantiate this finding.

In vitro comparative evaluation of physical and chemical properties of surface enamel after using APF and SDF with or without laser activation.

PURPOSE: To evaluate and compare the changes in physical and chemical properties of the enamel surface after application of Silver Diamine Fluoride (SDF), Acidulated Phosphate Fluoride (APF), LASER activated SDF and LASER activated APF. METHODS: Sample consisted of 72 freshly extracted healthy human premolar teeth, extracted for orthodontic purpose, free from caries, fracture or any anomalies. The selected samples were randomly divided into four groups (n = 18): Group 1 (SDF); Group 2 (APF); Group 3 (LASER activated SDF) and Group 4 (LASER activated APF). All samples were evaluated for values of DIAGNOdent at baseline, after demineralisation and after remineralisation. They were further divided and assessed for colour changes, surface alterations and fluoride content of surface enamel using Spectrophotometer, Scanning Electron Microscopy and Energy Dispersive X-ray Spectrometry respectively. The statistical analysis was done using One-Way ANOVA, Tukey's HSD test, Mann-Whitney U test and Kruskal-Wallis Test. RESULTS: Highest remineralising potential and maximum colour changes of surface enamel was exhibited by Group 3. Scanning Electron Micrographs of Group 3 and Group 4 exhibited regular globular structures of enamel whereas Group 1 and Group 2 showed irregular globular surface of the enamel at 2000× and 5000× magnification. Maximum fluoride uptake on the surface enamel was seen in Group 4 followed by Group 3. CONCLUSION: Use of LASER activated topical fluorides helps to achieve superior caries prevention. LASER activated APF can be used as an aesthetic alternative to SDF, as LASER activated APF showed higher uptake of fluoride on the enamel surface without discoloration effect.

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.

Prevention of Dental Erosion Caused by Fermented Milk: An In-vitro Study.

PURPOSE: This study aimed to assess the efficacy of three techniques for preventing dental erosion and thereby identify effective methods. The three techniques were: 1) adding calcium to fermented milk (2% Ca and 0.5% Ca); 2) topical application of fluoride to the teeth before exposure to fermented milk (acidulated phosphate fluoride [APF] gel and 0.05% NaF); and 3) a combination of the two techniques (APF gel + 0.5% Ca, 0.05% NaF + 0.5% Ca). MATERIALS AND METHODS: pH cycling was performed on bovine-tooth specimens alternately immersed in experimental solutions and artificial saliva. After treatment, the microhardness and roughness of the enamel surfaces were measured, and changes in the surface morphology were observed using atomic force microscope images. RESULTS: Microhardness did not differ statistically significantly between the 2% Ca and mineral water (negative control) groups (2% Ca: 295.34 ± 11.50; mineral water group: 294.76 ± 10.67; p > 0.05). Surface roughness did not differ statistically significantly between the 2% Ca, 0.05% NaF + 0.5% Ca, and mineral water groups (2% Ca: 16.81 ± 7.23; 0.05% NaF + 0.5% Ca: 15.77 ± 2.86; mineral water group: 13.35 ± 5.53; p > 0.05). The surface morphology did not change in the mineral water and 2% Ca groups. CONCLUSION: Considering that 2% calcium is a high concentration, adding a low concentration of calcium to fermented milk and applying a low concentration of fluoride daily decreased the reduction of surface microhardness and reduced the increase in surface roughness without causing marked changes in surface morphology. This confirms that combining the two techniques is an effective strategy to prevent dental erosion in-vitro.

Clinical evidence for professionally applied fluoride therapy to prevent and arrest dental caries in older adults: A systematic review.

OBJECTIVE: To assess the clinical evidence for professionally applied fluoride therapy to prevent and arrest caries in older adults. DATA/SOURCES: Two independent researchers searched the English literature published up to 31st Dec 2021 in five databases (PubMed, Scopus, the Cochrane Library, EMBASE, and Web of Science) for clinical trials with a comparison group on professionally applied fluoride therapy for caries prevention or arrest at older adults aged ≥60 years with any follow-up period. The outcomes were the mean difference in the number of new caries/caries-prevented fraction and caries arrest rate. The Cochrane guidelines were used for the risk of bias assessment. STUDY SELECTION/RESULTS: Five hundred and twenty-seven studies were identified, and seven studies were finally included. Five studies were rated as having 'low risk'. The root caries-prevented fraction of 38% silver diamine fluoride (SDF) solution, 5% sodium fluoride (NaF) varnish, and 1.23% acidulated phosphate fluoride (APF) gel were 25-71%, 64%, and 32%, respectively. Meta-analysis indicated a decrease in the number of new root caries by 0.55 (95% CI: 0.32-0.78; p < 0.001) and an overall proportion of arrested root caries of 42% (95% CI: 33% to 49%; p < 0.001) after receiving 38% SDF application at the 24-month follow-up. CONCLUSIONS: According to the findings, 5% NaF varnish and 1.23% APF gel prevented root caries, whereas 38% SDF solution prevented and arrested root caries in older adults. More well-designed clinical trials should be conducted to investigate various methods in caries prevention and arrest in older adults. CLINICAL SIGNIFICANCE: Preventive measures effective in other age groups may not suit older adults, as caries type and associated risk factors vary. To date, no systematic review has evaluated professionally applied fluoride therapy in older adults. Evidence from clinical trials in older adults could aid clinical practice and public health measures. The International Prospective Register of Systematic Reviews (PROSPERO) registration number: CRD42022307025.

An Extensive Comparison of the Clinical Efficiency of Acidulated Phosphate Fluoride (APF) and Neutral Sodium Fluoride (NaF) Oral Rinses in the Prevention of White Spot Lesions during Fixed Orthodontic Treatment: A Randomized Controlled Trial.

Background: The purpose of this randomized trial is to compare the efficacy of weekly once regime of neutral sodium fluoride (NaF) oral rinse with that of acidulated phosphate (APF) formulated daily mouth rinse in the reduction of white spot lesions (WSLs) associated with fixed orthodontic appliance treatment. Methods: The participants (n = 90) of this single-center, two-arm parallel study without a control group were randomly assigned with 1 : 1 distribution to each of the two groups after the bonding of brackets. Group A/test group 1 (n = 45) was given weekly rinse of neutral sodium fluoride (Colgate® PreviDent® Dental Rinse-0.2% NaF), and for group B/test group 2 (n = 45), an APF formulated daily oral rinse (Colgate® Ortho Defense@ PhosFlur® Rinse-0.044% w/v of NaF) was given for six months. The outcome was assessed by the International Caries Detection and Assessment System (ICDAS) index for scoring the demineralization, and for scoring gingivitis, Loe and Silness gingival index (GI) was utilized. Four different time points "T0"immediately before bonding procedures, "T1" after 4weeks, "T2" after 12 weeks, and "T3" after 24 weeks were taken to assess the ICDAS and GI scores. Results: The mean ICDAS scores for group A (NaF) were 0.025, 0.051, 0.093, and 0.113 and for group B (APF) were 0.014, 0.022, 0.038, and 0.015 at different points of time. The GI scores for group A were 0.008, 0.22, 0.33, and 0.38 and for group B were 0.003, 0.136, 0.181, and 0.097 at different time points. There was a statistically significant difference (p < 0.05) for both groups in terms of reducing WSL and GI. Conclusion: APF formulated daily oral rinse-0.044% w/v of NaF-is more effective than the weekly once regimen of 0.2% NaF oral rinse to prevent white spot lesions.

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).

Assessment of the preventive effects of Nd:YAG laser associated with fluoride on enamel caries using optical coherence tomography and FTIR spectroscopy.

OBJECTIVE: This in vitro study characterized and monitored, by Optical Coherence Tomography (OCT) and Fourier Transformed Infrared Spectroscopy (FTIR), the effects of the association of acidulated phosphate fluoride gel (APF-gel) and Nd:YAG (neodymiun:yttrium-aluminum-garnet) laser, as sequencial treatments, in the prevention of incipient enamel caries lesions. METHODS: 120 human enamel samples were randomized into 3 groups (n = 40): APF-gel (1.23% F-, 4 min.); Laser+APF (Nd:YAG laser irradiation-0.6W, 84.9J/cm2, 10Hz, followed by APF-gel); and APF+Laser (APF-gel followed by laser irradiation). The samples were subjected to a 15-day pH-cycling, evaluated by OCT (quantification of optical attenuation coefficient-OAC) and FTIR (analysis of carbonate and phosphate content) before treatments, after treatments, and on the 5th, 10th and 15th days of pH-cycling. The statistical analysis was performed (α = 5%). RESULTS: The Optical Attenuation Coefficient (OAC) assessed by OCT increases with the progression of demineralization, and the Laser+APF presented the highest values of OAC in 10th and 15th days of pH-cycling. Nd:YAG decreased the carbonate content after treatment regardless of the application order of the APF-gel, while APF-gel did not interfere in the composition of enamel. The carbonate content was also changed in the first 5 days of the pH-cycling in all groups. CONCLUSION: Nd:YAG laser irradiation before or after the application of APF-gel did not influence the appearance of incipient caries lesions, showing no synergistic effect. Regardless of the application order of the APF-gel, laser irradiation reduces the carbonate content of the enamel, which also changes during the demineralization process. However, irradiation before the application of APF-gel increased the speed of progression of the lesions, which positively impacts public health as it can prevent caries disease, even in high risk individuals. OCT and FTIR are suitable for assessing this effect.

Efficacy of 1.23% acidulated phosphate fluoride gel on non-cavitated enamel lesions: a randomized clinical trial.

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.

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

Fluoride release and fluoride-recharging ability of three different sealants.

BACKGROUND: We aimed to determine the fluoride release and fluoride-recharging ability of a sealant containing surface pre-reacted glass (S-PRG) ionomer filler particles (BeautiSealant) with a fluoride-releasing resin sealant (Helioseal F), and a glass-ionomer sealant (Fuji VII). METHODOLOGY: Forty-eight disc-shaped specimens of each material were immersed in deionized water to determine the fluoride release utilizing a fluoride ion-selective electrode. After 21 days, 8 specimens were soaked in 0.22% Sodium Fluoride solution for 2 min; 8 specimens were coated with 1.23% Acidulated Phosphate Fluoride (APF) gel for 4 min, and the fluoride-recharging ability was evaluated for 40 days. Data were analyzed using one way-ANOVA and Bonferroni post hoc tests. RESULTS: Total fluoride release over the 21-day period was: Fuji VII > BeautiSealant > Helioseal F, (P = 0.000). After refluoridation of the specimens with 0.22% Sodium Fluoride solution, the cumulative fluoride release during the 40-day period for each material was: BeautiSealant > Fuji VII > Helioseal (P = 0.000). After exposure to 1.23% APF gel, the cumulative fluoride release during the 40-day period for each material was: BeautiSealant > Fuji VII > Helioseal F (P = 0.000). CONCLUSION: Glass ionomer-based sealants (Fuji VII) exhibited higher initial fluoride release whilst the surface pre-reacted glass-ionomer filler containing sealant (BeautiSealant) demonstrated superior fluoride recharging properties.

Análise da rugosidade superficial de uma resina composta tratada com gel fluoretado em diferentes pH / Surface roughness analysis of a composite treated with fluoridated gel at different pH

Objetivo: O flúor acidulado é utilizado no controle da doença cárie, mas seus efeitos na superfície de resinas compostas são controversos. O objetivo do estudo é avaliar a rugosidade superficial de uma resina composta após a aplicação tópica de flúor in vitro. Métodos: Espécimes de resina Vittra (FGM) foram preparados (8mmx1mm) e polidos. Após avaliação do pH de produtos fluoretados, o de maior e menor pH foram selecionados para os ex-perimentos. Foram testados três grupos experimentais (n = 15): grupo 1 ­ flúor gel acidulado a 1,23% (Nova DFL) (menor pH:4,48±0,32), grupo 2 ­ flúor gel neutro a 2% (Nova DFL) (maior pH:7,03±0,40), grupo 3 ­ sem exposi-ção ao flúor (controle negativo). O experimento simulou o protocolo padrão clínico de aplicação de flúor (uma aplicação por semana, durante um minuto, por quatro semanas). A rugosidade superficial foi mensurada antes e após o tratamento através de microscopia confocal e a característica superficial avaliada por imagens reconstru-ídas. Foi realizado teste ANOVA (post-hoc de Bonferroni) para comparar médias da rugosidade superficial entre grupos. Resultados: O grupo exposto ao flúor gel acidu-lado apresentou os maiores valores de rugosidade (Ra: 0,29±0,08), sendo maior que o grupo exposto ao gel neutro (Ra: 0,21±0,08) e controle (Ra: 0,23±0,05) (p < 0,05), que não apresentaram diferença estatística entre si. Conclusão: O grupo exposto ao flúor acidulado mostrou rugosidade superficial maior que o controle, porém essa diferença pode ser clinicamente irrelevante. Novos estudos são necessários para avaliar se tal alteração aumenta a adesão bacteriana e se a resina deve ser polida após aplicações tópicas de flúor.

Aim: Acidulated fluoride is widely used to control dental caries, however, its effects on composites surfaces are controversial. This study aimed to evaluate the surface roughness of a composite af-ter a fluoride topical application in vitro. Methods: Vittra (FGM) composite specimens were made (8mmx1mm) and polished. After pH evaluation of fluoridated products, the ones with the highest and lowest pH were selected for the experiments. Three experimental groups (n = 15) were tested: group 1 - 1.23% acidulated fluoride gel (Nova DFL) (pH: 4.48±0.32), group 2 - 2% neutral fluoride gel (Nova DFL) (pH: 7.03±0.40), group 3 - no fluoride exposure (negative control). The experiment simulated the standard clinical fluoride application protocol (one application of one minute per week,in four weeks). Surface roughness was measured before and after treatment by confocal microscopy and the surface characteristic evaluated by reconstructed images. ANOVA (Bonferroni post-hoc) test was performed to compare means of surface roughness between groups. Results: The group exposed to acidulated fluoride gel presented the highest values of roughness (Ra: 0.29±0.08), being larger than the group exposed to neutral fluoride gel (Ra: 0.21±0.08) and control (Ra: 0.23±0.05) (p < 0.05), which showed no statistical difference between them. Conclusion: It was concluded that the group exposed to acidula-ted fluoride showed greater surface roughness than the control group, but this difference appears to be clinically irrelevant. Further studies are needed to assess whether this change increases bacterial adhesion and whether the resin should be polished after topical fluoride applications.

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.

Microhardness of bovine enamel after different fluoride application protocols.

The aim of the present study was to evaluate microhardness, mineral recovery and the enamel surface after the application of topical fluoride to artificial dental caries. Twenty-five bovine enamel blocks were prepared for artificial caries-like lesions and randomly divided into five groups (n=5): untreated (C control), 1.23% acidulated phosphate fluoride gel (APG), 2% neutral fluoride gel (NFG), 1.23% acidulated fluoride mousse (AFM) and fluoride varnish (5% Duraphat, DFV). Knoop microhardness (KHN) was evaluated after 7 and 14 days of treatment as well as 1 week after 28 days of treatment. Electron and confocal microscopy and energy dispersive spectroscopy were performed. KHN data were treated with two-way ANOVA (material×time) and Tukey's test at a 5% significance level. Differences were found among groups over time (p<0.001). Microhardness varied after 7 and 14 days of treatment and remained stable 1 week after 28 days of treatment. Mineral recovery and enamel topography varied among groups, with the fluoride varnish achieving the most uniform topography.

Er,Cr:YSGG laser associated with acidulated phosphate fluoride gel (1.23% F) for prevention and control of dentin erosion progression.

To evaluate the effect of Er,Cr:YSGG laser, associated with fluoride application, on the prevention/control of dentin erosion. Dentin slabs were embedded in acrylic resin, flattened, and polished. Half of the specimens were previously eroded (10 min immersion in 1% citric acid solution) and half were kept sound. The specimens (n = 10 each substrate) were randomly allocated into the experimental groups, according to the following treatments: control (no treatment); APF gel (1.23% F, 1 min); Er,Cr:YSGG laser irradiation (P1: 0.25 W, 20 Hz, 2.8 J/cm2, tip S75, beam diameter of 750 µm, 1 mm away from the surface); Er,Cr:YSGG laser irradiation (P2: 0.50 W, 20 Hz, 5.7 J/cm2, tip S75, beam diameter of 750 µm, 1 mm away from the surface); APF gel + Er,Cr:YSGG laser P1 and; APF gel + Er,Cr:YSGG laser P2. Afterwards, the specimens underwent an erosion-remineralization cycling, consisting of a 5-min immersion into 0.3% citric acid, followed by 60-min exposure to artificial saliva. This procedure was repeated 4×/day, for 5 days. Surface loss (SL, in µm) was determined by optical profilometry. Specimens from each group were analyzed by environmental scanning electron microscopy (n = 3). Data were statistically analyzed (α = 0.05). For the eroded specimens, APF gel presented the lowest SL, being different from the control. For the sound specimens, none of the groups differed from the control, except for Er,Cr:YSGG laser P2, which presented the highest SL. When substrates were compared, only the eroded specimens of the control and APF + Er,Cr:YSGG laser P1 Groups showed higher SL. Selective structure removal was observed for the laser-treated groups. None of the Er,Cr:YSGG laser parameters were effective in the prevention/control dentin erosion. The laser was also unable to enhance the protection of fluoride against dentin erosion.

Comparative evaluation of lithium disilicate ceramic surface and bond strength to dentin surface after treatment with hydrofluoric acid and acidulated phosphate fluoride gel: An In Vitro study.

CONTEXT: Long-term retention of the restoration depends on strength and durability of the bond of the luting composite resin to the tooth and the porcelain substrates. AIMS: This in vitro study was conducted to compare and evaluate the influence of hydrofluoric acid (HF) and acidulate phosphate fluoride (APF) gel-etched treatments on surface roughness and bond strength to dentin of a commercially available lithium disilicate ceramic (E-Max). SUBJECTS AND METHODS: Sixty lithium disilicate ceramic disks measuring 5 mm in diameter and 2 mm thick were fabricated and divided into three groups: Group A (n = 24), Group B (n = 24), and Group C (n = 12) and were subdivided to Group A1, A2, and A3which were surface treated with 1.23% APF gel (pH = 3-4) at different time intervals 4, 7, and 10 min, respectively. Group B1, B2, and B3 were surface treated with 1% APF gel (pH = 1-2) at different time intervals 4, 7, and 10 min, respectively. Group C were surface treated with 9.6% HF (pH = 1-2) for 1 min. Morphological changes obtained with the surface treatments were analyzed using a surface profilometer. STATISTICAL ANALYSIS: All specimens were subjected to a tensile bond strength test using a tensometer, and the obtained data were statistically analyzed using Kruskal-Wallis test. RESULTS: The surface roughness (µm) and bond strength (MPa) of lithium disilicate discs (samples) etched with 1.23% APF gel and 1% APF gel for 10 min and etched with 9.6% HF for 1 min showed no statistical significant difference among them. CONCLUSIONS: In this study, the lithium disilicate discs etched with 1.23% APF gel and 1% APF gel for 10 min showed similar surface roughness and bond strength to those etched with 9.6% HF for a minute.