Sound Human Premolars Research Articles

Effect of Diode Laser and Fluoride Varnish on Microhardness of enamel: An In Vitro Study

Introduction: White spots are a common complication of orthodontic treatment. Several prevention methods such as fluoride therapy and laser irradiation have been proposed, but there is still no conclusive evidence. Therefore, this study aimed to evaluate the combined application of diode laser and fluoride varnish in preventing white spots. Methods: Thirty-nine sound human premolars were extracted for orthodontic purposes and randomly divided into three groups of thirteen teeth each (C: Control, FV: fluoride varnish (5% sodium fluoride), and FV+L: fluoride varnish+980 nm diode laser (2 W)). The freshly extracted teeth were disinfected in a 0.5% chloramine T solution and stored in saline at room temperature. Each tooth was coated with nail polish, leaving a 2×3 mm2 window on the midbuccal. Surface treatments were applied, and primary Vickers microhardness was evaluated in the gingival sections. Then, the samples were immersed in alternating demineralizing (6 hours/day) and remineralizing (18 hours/day) solutions and incubated at 37 °C for 9 days to produce artificial caries. Afterward, the samples were immersed in a remineralizing solution for one day. Finally, secondary microhardness was measured. The data were analyzed using one-way ANOVA. Results: The primary microhardness was higher in groups C and FV than in group FV+L. The lowest secondary microhardness was recorded in group C, and there was no significant difference between the other two groups. The change in microhardness was greater in group C, while no difference was observed between the FV and FV+L groups. Conclusion: Within the limitations of this study, the combined application of laser irradiation and fluoride varnish may not improve white spot lesion (WSL) prevention compared to the use of fluoride varnish alone.

Effect of sodium hypochlorite and EDTA pretreatment on the resin infiltration efficacy and acid resistance of enamel white spot lesions: an in vitro study

BackgroundThis in vitro study aimed to evaluate the effect of sodium hypochlorite (NaOCl) and ethylene diamine tetraacetic acid (EDTA) as pretreatments on the resin infiltration efficacy and acid resistance of enamel white spot lesions (WSLs).MethodsEnamel blocks prepared from the buccal surfaces of sound human premolars were placed in a demineralisation solution for 3 days to establish artificial enamel WSLs. All the blocks with WSLs were randomly divided into four groups (n = 40 per group): RI (Control): resin infiltration only. N/RI: 5.25% NaOCl pretreatment + resin infiltration; E/RI: 17% EDTA pretreatment + resin infiltration; NE/RI: combined pretreatment of 5.25% NaOCl with 17% EDTA + resin infiltration; Enamel pore exposure was measured by using SEM observation and Image J software in each group after pretreatment prior to resin infiltration (n = 8 per group). Resin penetration depth and enamel surface microhardness were assessed after resin infiltration (n = 8 per group for each test) by a confocal laser scanning microscope and a Vickers’ microhardness test respectively. The remaining specimens were subjected 7 days of pH cycling after which surface enamel roughness and microhardness were assessed by an atomic force microscope and a microhardness test respectively.ResultsCompared to the control group, the enamel surface pore exposure (p = 0.007), resin penetration depth (p = 0.011) and enamel surface microhardness (p < 0.001) were all significantly increased after the pretreatment of 5.25% NaOCl alone or combined with 17% EDTA by one-way ANOVA. After pH cycling, no significant differences were found in enamel surface roughness or microhardness among the four groups (p = 0.55) by two-way ANOVA.ConclusionsEnamel surface pretreatment of 5.25% NaOCl or combined with 17% EDTA improved the efficacy of the resin infiltration of WSLs, but might be useless in enhancing the acid resistance of resin-infiltrated WSLs.

Elemental analysis and micromorphological patterns of tooth/restoration interface of three ion-releasing class V restorations

ObjectivesTo evaluate and compare the ion-releasing capability of three different restorative systems at the restoration/tooth interface elemental analysis using energy-dispersive X-ray technique. Additionally, micromorphological patterns of the restoration/tooth interfaces was investigated.Materials and methodsEighteen freshly extracted sound human premolars were collected for the study. The premolars were randomly assigned into 3 groups (n = 6) based on the type of restorative materials used: Giomer (Beautifill II), ion-releasing composite (Activa Presto), and RMGI (Riva Light Cure). Half of the specimens in each group were tested after 24 h (the “immediate group”), while the remaining half were tested after 6 months of storage in deionized water (the “delayed group”). Standardized box-shaped cavities along the cervical area of teeth crowns and restored them with the assigned restorative material following manufacturers’ instructions. The specimens were sectioned buccolingually into 2 halves. One half of each specimen was subjected to elemental analysis using energy-dispersive X-ray technique (EDX), while the remaining half was sputter coated and underwent micromorphological analysis of the restoration/tooth interface using a scanning electron microscope (SEM). The collected data from elemental analysis test were tabulated and subjected to statistical analysis.ResultsThe two-way ANOVA test showed significant differences in both phosphorus and calcium levels among the tested restorative systems (p < 0.05). In the immediate subgroup, RMGI recorded the highest phosphorus level (0.1527), followed by the ion-releasing composite (0.1172), while Giomer exhibited the least levels (0.0326) (p < 0.05). The ion-releasing composite group had the highest calcium level (0.2797), followed by RMGI (0.248), and Giomer (0.2385) respectively (p < 0.05). In the delayed subgroups, Giomer recorded the highest phosphorus level (0.1526), followed by the ion-releasing composite (0.1058), and RMGI group (0.0466) respectively (p < 0.05). RMGI had the highest calcium level (0.2801), followed by the ion-releasing composite (0.2659), and Giomer had the lowest level (0.1792) (p < 0.05). The micromorphological analysis of the restoration/tooth interfaces showed good adaptation between the composite and tooth substrate in different restorative groups.ConclusionsThe ion-releasing capability of the three restorative systems appears to be comparable. The rate of mineral release and diffusion is affected by time and composition.

Comparative Evaluation of Remineralization Potential and Surface Microhardness of Three Different Remineralizing Agents on Artificial Enamel Lesions: An In vitro Study

Abstract Aim and Objective: The aim and objective of this study were to evaluate and compare the remineralizing potential of calcium sucrose phosphate (Toothmin), fluoride-hydroxyapatite-xylitol (Remin Pro) and casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) (GC Tooth Mousse) and their impact on surface microhardness of enamel using confocal laser microscopy and Vickers microhardness tester, respectively. Materials and Methods: Eighty sound human premolars extracted for orthodontic or periodontal reasons were collected. Random allocation of 80 samples was done into five experimental groups (n = 16). After derooting, crowns were embedded in an acrylic resin mold with the buccal surface positioned upward, lying flat, and parallel to the horizontal plane. All the samples in Group 1, 3, 4, and 5 were kept in demineralizing solution for 5 days until a white spot lesion was created on the surface of the enamel. Samples were washed with deionized water and stored in artificial saliva. The samples in Groups 3, 4, and 5 were treated with the respective remineralizing agent. Samples of each group (n = 15) were divided into two subgroups, i.e., Subgroups A and B for confocal laser microscopic and Vickers microhardness assessment, respectively. Results: Maximum depth of remineralization was seen in calcium sucrose phosphate (197.94 ± 11.30) followed by the CPP-ACP (185.21 ± 11.20) and least in the fluoride-hydroxyapatite-xylitol (161.91 ± 14.39) group. Maximum microhardness increase was seen in the calcium sucrose phosphate (318.31 ± 14.22) followed by the CPP-ACP (286.38 ± 8.67) and least in fluoride-hydroxyapatite-xylitol (236.06 ± 16.71) group and difference was statistically significant (P &lt; 0.001). Conclusion: Calcium sucrose phosphate showed the highest remineralization depth and greater increase in surface microhardnesss of enamel followed by CPP-ACP and fluoride-hydroxyapatite-xylitol, and the difference was statistically significant.

The Effect of Resin Infiltration Technique on the Calculated Color Change of Demineralized Lesions of Different Severities.

To assess the color change of demineralized enamel lesions of different severities after resin infiltration using both clinical spectrophotometry and digital photography. Sixty sound human premolars were randomly divided into 3 groups according to the demineralization level. All the teeth were immersed in a demineralizing solution of a pH adjusted to 4.4 at 37°C. Three levels of demineralization were obtained (D1 shallow, D2 moderate, D3 deep) according to the demineralization time. The demineralized area was then infiltrated by low-viscosity resin (ICON, DMG, Germany). Two instrumental methods were utilized to assess the color difference, a clinical spectrophotometer and digital photography at three time points (sound, demineralized, and infiltrated enamel) to calculate the color difference between sound and demineralized enamel (ΔE1) and between sound and infiltrated enamel (ΔE2). Statistical analysis was performed by ANOVA, followed by Tukey's post hoc test. The correlation was analyzed using linear regression. Two-way ANOVA showed statistically significant differences for both levels of the study (p≤0.05). The color change (ΔE1) and (ΔE2) for different demineralization levels showed statistically significant differences between all groups. For both clinical spectrophotometry and digital photography, D3 showed the highest difference followed by D2 and then D1. As for (ΔE1) calculations, digital photography had a significantly higher difference than spectrophotometry for the D1 group (5.47±0.93 vs 2.78±0.58). As for (ΔE2) digital photography had a statistically significantly lower difference than spectrophotometry (5.55±1.05 vs 6.48±0.76) for the D3 group. Color correction after resin infiltration is affected by the demineralization level of enamel. Clinical spectrophotometry and digital photography can detect similarly the color change of demineralized enamel after resin infiltration in shallow and moderate demineralization. However, in deep demineralization clinical spectrophotometry tends to exaggerate the color change compared to digital photography.

Physicochemical characteristics and discolouration potentials of Pulpine mineral® and Pulpine NE®

ABSTRACT Aim: To compare the physicochemical properties (solubility, pH, radiopacity and crown discoloration) of Pulpine mineral (PMIN) and Pulpine NE (PNE) with the conventional material, mineral trioxide aggregate (MTA). Methodology: Specimens of the tested materials were prepared according to the manufacturer’s instructions using split Teflon ring molds. Solubility was evaluated by the percentage of material mass loss over 24 h and one week. The alkalinity was measured after each evaluation period using a pH meter. Other specimens were digitally radiographed on a size 2 sensor plate along with an aluminum step wedge to analyze the radiopacity by the Image J software. Finally, crown discoloration was assessed after applying the tested materials in the pulp chamber of sound human premolars using spectrophotometer. All data were statistically analyzed. Results: Compared to MTA, both materials had significantly higher solubility and lower radiopacity (P&lt;0.05). The alkalinity of PMIN was higher than that of MTA and PNE. Unlike PMIN, PNE and MTA caused crown discoloration. Conclusions: PMIN exhibits promising results related to high alkalinity and adequate color stability but it needs modifications for radiopacity and solubility.

Enamel changes of bleached teeth following application of an experimental combination of chitosan-bioactive glass

BackgroundConsidering the extensive use of bleaching agents and the occurrence of side effects such as enamel demineralization, this study aimed to assess the enamel changes of bleached teeth following the experimental application of chitosan-bioactive glass (CH-BG).MethodsIn this in vitro study, CH-BG (containing 66% BG) was synthesized and characterized by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Thirty sound human premolars were bleached with 40% hydrogen peroxide, and the weight% of calcium and phosphorus elements of the buccal enamel surface was quantified before and after bleaching by scanning electron microscopy/ energy-dispersive X-ray spectroscopy (SEM, EDX). Depending on the surface treatment of the enamel surface, the specimens were divided into three groups (n = 10): control (no treatment), MI Paste (MI), and CH-BG. Then the specimens were stored in artificial saliva for 14 days. The SEM/EDX analyses were performed again on the enamel surface. Data were analyzed by one-way ANOVA and Tukey’s test and a p-value of < 0.05 was considered statistically significant.ResultsIn all groups, the weight% of calcium and phosphorus elements of enamel decreased after bleaching; this reduction was significant for phosphorus (p < 0.05) and insignificant for calcium (p > 0.05). After 14 days of remineralization, the weight% of both calcium and phosphorus elements was significantly higher compared to their bleached counterparts in both MI and CH-BG groups (p < 0.05). Following the remineralization process, the difference between MI and CH-BG groups was not significant (p > 0.05) but both had a significant difference with the control group in this regard (p < 0.05).ConclusionsThe synthesized CH-BG compound showed an efficacy comparable to that of MI Paste for enamel remineralization of bleached teeth.

Effects of Two Remineralizing Agents in Combination with Er:YAG and CO2 Laser Irradiation on Microhardness of Demineralized Enamel: A Preliminary In Vitro Study.

Objectives: This study assessed the effects of two remineralizing agents namely MI Paste Plus containing casein phosphopeptide amorphous calcium phosphate fluoride (CPP-ACFP) and Remin Pro containing hydroxyapatite, fluoride and xylitol (HFX) with/without erbium-doped yttrium aluminium garnet (Er:YAG) and CO2 laser irradiation on demineralized enamel microhardness. Materials and Methods: In this in vitro study, 70 sound human premolars were mesiodistally sectioned, demineralized at a pH of 4.6 for 8 hours, and randomly divided into 7 remineralization groups (n=10): of (I) MI Paste Plus (CPP-ACFP), (II) Remin Pro (HFX), (III) MI Paste Plus+CO2 laser (0.7 W power, 50 Hz), (IV) Remin Pro+CO2 laser, (V) MI Paste Plus+Er:YAG laser (1 W power, 10 Hz), (VI) Remin Pro+Er:YAG laser, and (VII) negative control. The Vickers hardness number of specimens was then measured. The groups were compared by one-way ANOVA and Tukey's test (α=0.05). Results: The mean microhardness was 319.8±49.9, 325.3±44.6, 359.4±35.7, 296.4±33.7, 319.9±58.1, 358.9±28.4, and 240.0±41.6 kg/mm2 in groups 1 to 7, respectively. The difference in microhardness was significant among the groups (P<0.0001). Pairwise comparisons revealed significant differences in microhardness between all groups (P≤0.03) except between groups 1 and 2, 1 and 5, 2 and 5, and 3 and 6 (P>0.05). Conclusion: Both Remin Pro (containing HFX) and MI Paste Plus (containing CPP-ACFP) can cause enamel remineralization. MI Paste Plus+CO2 laser irradiation and Remin Pro+Er:YAG laser irradiation were significantly more effective than the application of each remineralizing agent alone.

The effect of combined use of resin infiltration with different bioactive calcium phosphate-based approaches on enamel white spot lesions: An in vitro study

ObjectivesThis in vitro study aimed to evaluate the effect of resin infiltration combined with casein phosphopeptide-amorphous calcium phosphate with fluoride (CPP-ACPF) or bioactive glass (BAG) on the stability of enamel white spot lesions (WSLs) treatment. Materials and methodsEighty-four enamel blocks were prepared from the buccal surfaces of sound human premolars. All enamel blocks were placed in a demineralisation solution for 3 days to establish the artificial enamel WSLs. Enamel blocks with WSLs were randomly divided into three groups (n = 28 each group): RI/B: one-off resin infiltration followed by twice daily BAG treatment; RI/C: one-off resin infiltration followed by twice daily CPP-ACPF treatment; RI: one-off resin infiltration treatment only (as control) and subjected to pH cycling for 7 days. Surface morphology, elemental analysis, crystal characteristics, surface roughness and microhardness of enamel surfaces were investigated by scanning electron microscopy and energy-dispersive spectrometry observation, X-ray diffraction (XRD), atomic force microscope and Vickers’ hardness testing, respectively. ResultsMean values of the surface roughness (mean±standard deviation (nm)) were 24.52±5.07, 27.39±5.87 and 34.36±4.55 for groups RI/B, RI/C and RI respectively (p = 0.003). The calcium to phosphate ratios were 1.32±0.16, 1.22±0.26 and 0.69±0.24 for groups RI/B, RI/C and RI respectively (p < 0.001). XRD revealed apatite formation in all three groups. The mean enamel surface microhardness (kg/mm2) of the groups were 353.93±28.49, 339.00±27.32 and 330.38±22.55 for groups RI/B, RI/C and RI respectively (p = 0.216). ConclusionsResin infiltration combined with CPP-ACPF or BAG remineralisation appears to improve the surface properties of WSLs. Clinical SignificanceThe combination of resin infiltration and CPP-ACPF/BAG remineralisation may be a potential treatment for the management of the WSLs.

Microleakage of Root Canal Sealed with Temporary Endodontic Sealing Materials

To measure the microleakage of different materials used as temporary endodontic sealing materials and to compare between them. Sixty sound human premolars extracted for orthodontic purpose, caries and cracks free were used. Teeth were divided into 6 groups depending on type of temporary materials (glass ionomer cement, zinc phosphate cement, amalgam, temporary filling "zinc oxide eugenol") for temporization and control groups (negative and positive). For each tooth, an access opening was done followed by instrumentation, irrigation and dryness. Then application of different temporary materials. Evaluation of marginal microleakag e (tooth – restoration interface) were done by using dye penetration test. The study was done in Department of Conservative Dentistry, College of Dentistry, University of Mosul. The results showed significant differences (p&lt; 0.05) in marginal microleakage among groups tested. But there were no significant difference between buccal and lingual tooth restoration – interface for each group. Glass i onomer cement showed less microleakage at tooth – restoration interface when compared with other temporary filling mater ials which used in this study. Glass ionomer cement has sup erioer effect on reduction of microleakage when compared with other temporary filling,when used for temporization had more ability to reduce microleakage than zinc phosphate cement, amal gam and lastly temporary filling (zinc oxide eugenol).

Effect of Two Remineralizing Agents on Dentin Microhardness of Non-Caries Lesions.

The prevalence of non-carious dentin lesions is on the rise mainly due to improved life expectancy. Successful management of these lesions is often challenging, and given that dentin can be remineralized, adverse consequences due to progression of these lesions can be prevented or minimized as such. This study aimed to assess the effect of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) and Remin-Pro remineralizing agents on dentin microhardness of non-carious dentin lesions. This in vitro, experimental study evaluated 36 extracted sound human premolars. The teeth were decoronated at the cementoenamel junction. Enamel was removed, and dentin was exposed at the cervical third of the buccal surface. The primary microhardness of dentin was then measured. The teeth, standardized in terms of dentin microhardness, then underwent demineralization by acid etching and were subjected to microhardness test again. They were then randomized into three groups for treatment with CPP-ACP, Remin-Pro, and artificial saliva (control), and dentin microhardness was measured for the third time after treatment. Data were analyzed using ANOVA. Within group comparisons showed a significant difference in microhardness at the three time points in all three groups (p< 0.005). Between-group comparisons revealed that the microhardness of the three groups was not significantly different at baseline or after demineralization. However, the microhardness of the three groups was significantly different after the intervention (p= 0.000). Pairwise comparisons revealed significantly higher microhardness in the CPP-ACP group than the other two groups (p= 0.003). Remin-Pro and the control groups were not significantly different in this respect (p= 0.340). CPP-ACP can be used for remineralization of non-caries dentin lesions; however, Remin-Pro does not appear to be effective for this purpose.

Effect of Fluoride Release on Enamel Demineralization Adjacent to Orthodontic Brackets.

This study aimed to evaluate the ability of fluoride-releasing adhesives to inhibit enamel demineralization surrounding orthodontic brackets. Two groups of 40 sound human premolars were sectioned mesio-distally. The halves were varnished, and orthodontic brackets were bonded with different adhesive materials. An area 1 mm wide surrounding the brackets was left exposed. Each specimen was immersed daily in a pH cycle for 28 days. In the second group, the specimens were exposed daily to a fluoride solution (250 ppm F-) at 37°C. The fluoride release from different groups was measured. Quantitative light-induced fluorescence (QLF) was used to quantify fluorescence loss of enamel surfaces adjacent to the brackets. Results were statistically analyzed using ANOVA at (p<0.05). Fluoride released from the three fluoride-releasing adhesives was significantly higher (p<0.001) in the group with daily fluoride exposures than in the group without fluoride exposures. Enamel adjacent to brackets bonded with Fuji Ortho LC, Ketac Cem, and Dyract Cem showed significantly less (p<0.001) changes in (ΔQ) value (less demineralization) than enamel bonded with Transbond, the control adhesive material. Using fluoride-releasing adhesives significantly reduced the level of demineralization adjacent to orthodontic brackets.

Effect of Internal Bleaching on the Microshear Bond Strength of Composite Resin to Dentin in Recently Restored Teeth

Background: This study aimed to assess the effect of internal bleaching on the microshear bond strength of composite resin to dentin in recently restored teeth.&#x0D; Methods: This in vitro, experimental study evaluated 40 sound human premolars. The teeth were sectioned below their cementoenamel junction. Access cavity was prepared, pulpal tissue was removed and filled with glass ionomer. The teeth were then randomly divided into 4 groups. In the control group, no internal bleaching was performed and dentin surface was restored with composite. In group 2, internal bleaching with 35% hydrogen peroxide (Opalescence, ultradent) was performed 4 weeks after composite restoration. Bleaching was performed immediately after restoration of teeth in groups 3 and 4. Teeth were etched with 35% phosphoric acid for 15 seconds, rinsed, dried, and primer and adhesive (Adper Scotchbond Multipurpose) were applied. The teeth were then restored with Z250 (3M ESPE) microhybrid resin composite. Teeth were sectioned into 1 mm2 sections and underwent micro-shear bond strength test. In groups 1 to 3, bond strength was measured after 24 hours while in group 4, it was measured after 1 month. Data were analyzed using one-way ANOVA.&#x0D; Results: The mean micro-shear bond strength of composite to dentin was maximum in group 2 and minimum in group 3. However, the difference in this respect was not significant among the groups (p&gt;0.05).&#x0D; Conclusion: In teeth requiring immediate esthetic restorations, treatments can be performed after non-vital bleaching with no time restriction and adequately high bond strength comparable to non-bleached teeth.

Evaluation the antibacterial efficacy of sodium hypochlorite in combination with two different photodynamic therapy protocols against Enterococcus Faecalis in Infected root canals: An in-vitro experiment

BackgroundPhotodynamic therapy (PDT) is an antimicrobial approach that can be used as an adjunctive safe technique for root canal disinfection. In this study, we aimed to evaluate the antibacterial efficacy of PDT with indocyanine green and toluidine blue in combination with sodium hypochlorite (NaOCl) in compared with NaOCl alone against Enterococcus faecalis in infected root canals. MethodsSixty five root canals of sound human premolars were collected. First, the teeth were sterilized, then 60 root canals were inoculated with the E. faecalis, and 5 samples served as negative control remained uncontaminated. The contaminated root canals were randomly assigned into 4 experimental groups (n=15): (1) NaOCl, (2) NaOCl+ PDT-1 (toluidine blue + 630nm LED), (3) NaOCl+ PDT-2 (indocyanine green + 808nm diode laser), and (4): positive control (no treatment). Then, the colony-forming units (CFU/mL) of E. faecalis were calculated in all the groups. Moreover, 5 samples from each group were examined under a scanning electron microscope. The data were analyzed by independent T-test and the Mann-Whitney U test at the significance level of 0.05. ResultsThe CFU count was significantly lower in the indocyanine green-PDT group in comparison with other groups (p˂0.05). The mean of CFU in the positive control group was significantly higher than the other groups (p˂0.05). No significant difference was detected between NaOCl and toluidine blue –PDT group (p=1.00). ConclusionIndocyanine green- PDT improved the antibacterial effects of NaOCl against E. faecalis, while toluidine blue – mediated PDT had no significant additional effect on NaOCl.

Evaluation of the laser wavelength role on tooth bleaching in terms of color change, roughness, and microhardness with pulpal rapid temperature monitoring: an in vitro study.

This in-vitro study evaluates the efficacy of the teeth bleaching approach using different laser wavelengths (405nm blue diode, 940nm infrared diode, and Er,Cr:YSGG 2780nm lasers) in comparison to the conventional method using light-emitting diode (LED) sources (420-480)nm. Eighty caries-free sound human premolars were randomly divided into four groups (N=20). Each group received a different bleaching procedure. Then each group was further subdivided into two subgroups (N=10) stained with different solutions. The pulp chamber temperature rise was recorded using an optical fiber sensor with a novel design and fabrication. The color was analyzed using a digital spectrophotometer. Five samples of each subgroup were tested for surface roughness, while the others were tested for Vickers microhardness. The bleaching process with a short wavelength 405nm blue diode laser showed the best results for the shade, with a minimum pulpal temperature increase indicating no possible necrosis and hence maintaining tooth vitality. Additionally, a remarkable reduction in bleaching time was achieved compared to the conventional approach. This process also yielded the highest color change (Δ E) and increased microhardness, with no noticeable change to the tooth roughness. The 405nm blue diode laser applied for bleaching showed the best bleaching activity against tested stains and negligible pulpal temperature rise with a noticeable reduction in the bleaching time. The proposed novel method to measure temperature change could be used to develop a promising smart sensor for quick, effective, repeatable, and in-situ monitoring of human body temperature.

Theobromine versus casein phospho-peptides/Amorphous calcium phosphate with fluoride as remineralizing agents: effect on resin-dentine bond strength, microhardness, and morphology of dentine

BackgroundThis study aimed to assess the impact of theobromine and casein phospho-peptides/amorphous calcium phosphate with fluoride (CPP-ACPF) on the resin-dentine bond strength, microhardness, and dentine morphology.MethodsA total of 18 sound human molars for micro-tensile bond strength (µTBS), 20 sound human premolars for microhardness, and 30 premolars for Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) were used. Based on the pre-treatment used, teeth were split into six groups; sound dentine, demineralized dentine, and demineralized dentine treated with theobromine (Sigma Aldrich) and MI paste plus (GC International, USA) for two-time intervals; 5 min and 1 month. The bonded teeth were sectioned to produce 1 mm2 resin-dentine sticks which were evaluated for µTBS using a universal testing device (Instron 3365, USA). The dentine microhardness was tested by using the Vickers microhardness tester (Nexus 4000 TM, Netherlands). The pre-treated dentine surface was examined using SEM/EDX (Neoscope JCM-6000 plus Joel benchtop SEM, Japan). µTBS results were analysed with two-way ANOVA. Microhardness and EDX results were analysed with two-way mixed model ANOVA. The significance level was set at (p ≤ 0.05).ResultsWhile both remineralizing materials at the two-time intervals demonstrated µTBS comparable to sound dentine (46.38 ± 12.18), the demineralized group demonstrated statistically the lowest µTBS (p < 0.001). Whether used for 5 min or 1 month, theobromine significantly increased the microhardness (50.18 ± 3.43) and (54.12 ± 2.66) respectively (p < 0.001), whereas MI paste only increased the hardness (51.12 ± 1.45) after 1 month (p < 0.001).ConclusionsThe pre-treatment of demineralized dentine with theobromine for 5 min or 1 month could enhance its bond strength and microhardness while for MI paste plus, only 1-month application was efficient to ensure remineralization.

Shear Bond Strength of Ceramics to Chlorhexidine versus Pomegranate Peel Extract – Pretreated Dentin: A Randomized Control Study

Background: Durable tooth bonding is the hallmark of successful minimally invasive all-ceramic restorations. Aim: The aim of this study was to assess the shear bond of ceramics to pretreated dentin with chlorhexidine (CHX) or pomegranate peel extract (PPE), compared to no pretreatment (control), after thermocycling. Materials and Methods: Thirty extracted sound human premolars were enrolled and mounted in autopolymerized acrylic blocks. Occlusal 3 mms were removed to obtain the flat dentin surfaces. Teeth were randomly distributed among three equal groups (n = 10) according to dentin pretreatment; (group I: No pretreatment (control), group II: 2% CHX, and group III: PPE pretreatments). Ceramic discs (4 mm × 4 mm × 1.5 mm) were milled from zirconia-reinforced lithium silicate (ZLS) blocks (Celtra Duo, Dentsply), and cemented to prepared teeth with self-adhesive cement (RelyX Unicem, 3M). All samples were thermocycled for 2500 cycles at 5°C–55°C. Shear bond strengths (SBSs) were assessed followed by statistical analysis using one-way ANOVA, followed by Tukey’s post hoc test. The significance level was set at P ≤ 0.05 in all tests. Results: CHX-pretreated group showed the best SBS (18.40 ± 1.27 MPa) after thermocycling, compared to control (12.24 ± 1.20 MPa) and PPE-pretreated groups (5.89 ± 0.24 MPa) with a statistically significant difference among all groups (P ≤ 0.05). Conclusions: In contrary to PPE, CHX-dentin pretreatment kept better SBS to ceramics after thermocycling, providing an access to minimally invasive, yet durable esthetic restoration.

Comparison of the shear bond strength of new and recycled metallic brackets using different adhesive materials : an in vitro study.

To evaluate and compare shear bond strength (SBS) of new and recycled metallic brackets bonded to conditioned and reconditioned enamel, using two different adhesive materials. 72 extracted sound human premolars were randomly divided into 6 groups. Transbond XT light cured composite (LCC) and Fuji Ortho LC resin-modified glass ionomer (RMGI), were used as adhesive materials. In groups 1 and 2 (control), new brackets were bonded to sound premolars using either LCC or RMGI, respectively. In Groups 3 and 4, new brackets were bonded to reconditioned enamel; and in groups 5 and 6, sandblasted recycled brackets were rebonded to reconditioned enamel. After 5.000 thermal cycles between 5ºC and 55ºC, SBS was evaluated and adhesive remnant on the enamel assessed using the ARI index. Statistical analyses included Shapiro-Wilk, ANOVA, Fligner-Killeen ANOVA and Tukey tests. The statistical analysis showed no significant difference in SBS comparing control and experimental groups for either new or recycled brackets (p = 0.848). The SBS was significantly higher in brackets bonded with LCC (15.7 MPa) than RMGI (11.6 MPa) (p = 0.006). Adhesive failure was the most frequent, with the adhesive remnant covering more than 50% of the bracket base. No significant differences were observed in SBS using either new or recycled brackets, regardless of the dental surface treatment (conditioned or reconditioned). Significantly higher SBS values were obtained with LCC adhesive. Adhesive failure prevails in all groups.

Influence of adhesive application method and thermocycling on the bonding performance of different adhesive systems to dentin

Aim: To assess the effect of multiple layers application of different adhesive systems on the microshear bond strength (μSBS) of dentin with and without thermocycling. Materials and Methods: Two hundred forty sound human premolars had their enamel surfaces removed to expose even surfaces of dentin. The teeth were mounted in acrylic resin blocks and then assigned arbitrarily into four main groups (n = 60) representing the investigated adhesives (a self-etch [SE] adhesive, a total-etch [TE] adhesive, and a multimode [MM] adhesive used in TE and SE modes). Individually, the main groups were equally alienated into three subgroups (n = 20), each representing the number of the applied adhesive layers (one layer [1L], two layers [2L], and three layers [3L]). Then, each respective subgroup was divided subsequently into two equal divisions with n = 10 each according to thermocycling (with and without thermocycling). Each occlusal surface received three composite microrods. Prepared specimens were reserved in distilled water at temperature of 37°C until the μSBS test was performed after 24 h or after thermocycling for 3000 cycles at 5°C–55°C water bath. Results: A three-way analysis of variance (ANOVA) disclosed that multilayer application, adhesive type, and thermocycling showed a significant statistical impact on μSBS. The 1L, 2L, and 3L groups showed a statistically significant difference between the groups. The 3L groups showed the highest μSBS, whereas 1L groups recorded the least μSBS. Within the adhesive groups, a statistically significant difference was evident. The highest μSBS was recorded for TE, whereas SE recorded the least μSBS. Thermocycling (TC) has a statistically significant effect on μSBS and “no-thermocycling” (T0) groups recorded higher μSBS than thermocycled groups. Conclusion: Multilayer application of the tested adhesives had the potential to increase dentin μSBS.

Comparative Evaluation of Micro Tensile Bond Strength and Microleakage of Ionoseal Glass-Composite as a Fissure Sealant Material, Following Four Different Enamel Surface Pretreatments.

Sealants are employed to prevent carious lesion initiation and to arrest caries progression by providing a physical barrier that inhibits accumulation of microorganisms and food particles in pits and fissures. The two most common materials used for sealing pits and fissures are resins and glass-ionomers. Ionoseal from VOCO company is one of the light curing glass-ionomer composite cements, whose mechanical properties should be investigated. The aim of this study was to compare the micro tensile bond strength and micro leakage of Ionoseal with different surface pretreatments. This in vitro experimental study was conducted on five groups of 95 sound human premolars. Each group consisted of five teeth for the micro tensile test and 14 teeth for the micro leakage test. The groups regarding the materials and the methods used were defined as Group 1: 35% phosphoric acid + total etch adhesive + Ionoseal, Group 2: universal adhesive+Ionoseal, Group 3: 35% phosphoric acid + Ionoseal,Group 4: Ionoseal, and Group 5 (control group): 35% phosphoric acid+Embrace fissure sealant. On the pre-pared buccal enamel of each tooth, a 5 mm block of the sealing material was created and thermo cycled. The specimens were serial sectioned to a cross section of about 1×1mm and loaded in a tensile pressure (0.5 mm/min) until failure occurred. For the micro leakage test, the sealing material was placed into the prepared occlusal fissures and teeth were thermo cycled, and then immersed in 5%methylene blue. A section was made buccolingually; the dye penetration rate was measured based on Williams and Winter criteria under a stereomi-croscope. Data was analyzed with one-way ANOVA test and Kruskal-Wallis test. Mean micro tensile bond strength was significantly different between the groups (p< 0.001), and was significantly higher in Group 1. There was no significant difference between the frequency of modes of failure (p= 0.81). The rate of micro leakage was significantly different between the five groups (p< 0.001) and in Group 1 and 3; it was significantly lower than the other three groups. Ionoseal can be used successfully as a fissure sealant material. Etching the enamel surface with phosphoric acid is necessary and the use of a bonding agent before Ionoseal placement improves results.