Effect of Thermal Cycling Aging on the Surface Microhardness and Roughness of Resin-Infiltrated Enamel Lesions

With the widespread use of resin infiltration, its properties have drawn increasing attention. The objective of this study was to investigate the effect of resin infiltration on the surface microhardness and roughness of enamel lesions after thermal cycling aging. Tooth blocks were made from extracted premolars and placed into a control group, resin-infiltrated group or demineralized group. Before and after the aging procedure, the surface microhardness and surface roughness was measured. Before the aging procedure, the surface microhardness of the control group, resin-infiltrated group and demineralized group was 302.14 (±9.77) HV, 146.62 (±8.22) HV, and 28.85 (±2.21) HV (p 0.001), respectively. After the aging procedure, the surface microhardness of the control group, resin-infiltrated group and demineralized group decreased by 9.42%, 16.59%, and 20.75% ( p 0.001), respectively. Before the aging procedure, the surface roughness of the control group, resin-infiltrated group and demineralized group was 0.29 (±0.04) μm, 0.32 (±0.04) μm, and 0.39 (±0.07) μm (p = 0.009), respectively. After the aging procedure, the surface roughness of the control group, resin-infiltrated group and demineralized group increased by 9.85%, 8.31%, and 17.37% (p = 0.634), respectively. Resin infiltration can improve the surface microhardness and surface roughness of demineralized teeth in an artificial enamel caries model. The treatment also shows good aging resistance after thermal cycling. The infiltrant resin provided a suitable material for early enamel caries.

Use of Ytterbium Trifluoride in the Field of Microinvasive Dentistry—An In Vitro Preliminary Study

Background: The aim of this study was an attempt at determining the quantity of the degree of the addition of ytterbium trifluoride as a marker, aimed at facilitating the observation and assessment of the effectiveness of penetration into the decalcified enamel of human teeth of an experimental preparation with the characteristics of a dental infiltrant and a commercially available commercial preparation called Icon. Methods: The test material was 20 decalcified human teeth. The first half of the batch was soaked in Icon, the second half in an experimental preparation with the characteristics of a dental infiltrant and with a component responsible for bacteriostaticity. Ytterbium trifluoride was added to both preparations to facilitate the microscopic observations: 20 mg/1 g in the first phase of the experiment, 60 mg/1 g in the second phase. Results: YbF3 particles could not be found in the teeth from the first phase of the experiment. Particles rich in ytterbium could be found only in the teeth from the second phase of the experiment, with three times the content of ytterbium. Conclusion: The addition of 6% ytterbium trifluoride (both commercial and laboratory synthesized) facilitates microscopic observation, allowing the conclusion that both Icon and the experimental preparation with the characteristics of a dental infiltrant penetrate the decalcified enamel of a human tooth. The SEM analysis of the preparations in terms of content and particle size of ytterbium trifluoride shows that the distribution is heterogeneous. Large size particles predominate, yet particles with a diameter of less than 1 µm were also found. This may confirm the fact that most of them have probably agglomerated. The method of scattering YbF3 nanoparticles in the infiltrant resin requires further work so that they do not appear as agglomerates.

Effect of Conditioning Protocols and Ultrasonic Application of an Infiltrant Resin in White Spot Lesions

The aim of this study was to evaluate different conditioning protocols and sonic/ultrasonic application of an infiltrant resin (IR) in artificial white spot lesions (AWSL). the V/L surfaces of 48 molars were induced to an AWSL and divided in 6 groups, according to the conditioning protocols and application technique: 15% hydrochloric acid (HA) + manual application of the IR; HA + 37% phosphoric acid (PA) + manual application of the IR; HA + ultrasonic application (U) of the IR; HA + sonic application (S) of the IR; PA+HA+S; and PA+HA+U. For the Penetration Depth (PD), the crowns were etched with HA for 120s. The IR Icon® (DMG) was applied according to the manufacturer`s instructions. The crowns were dye penetrated (0.1% red fluorophore rhodamine B isothiocyanate for 12h) and bleached with 30% hydrogen peroxide for 12 h. The discs were immersed in a 50% ethanol solution, containing 100 µM of sodium fluorescein. The PD (in µm) was measured using confocal laser scanning microscopy (20x). The bond strength (BS) was performed by michoshear test (0.5 mm/min). Data were submitted to 2-way ANOVA and Tukey (α=0.05). For BS, the interaction was not significant (p>0.05). For PD, the main factors were significant (application - p<0.001; conditioning technique - p=0.003). The ultrasonic application showed the highest PD values. PA+HA presented higher results than HA. The sonic/ultrasonic applications and the use of phosphoric acid prior to hydrochloric acid improved PD of the infiltrant resin. Conditioning protocols or application techniques did not influence BS values.

Amelogenesis Imperfecta: A Non-Invasive Approach to Improve Esthetics in Young Patients. Report of Two Cases

Objective–Evaluate esthetic and functional efficacy of infiltrant resin (Icon, DMG, Hamburg, Germany) in Amelogenesis Imperfecta's treatment. Study design: Two adolescent patients, G.S. (13 years old) and C.M. (15 years old), affected by the hypomaturation type of Amelogenesis Imperfecta, were treated with Icon resin and were followed for twelve months. Results: Treated teeth show an excellent aesthetical result immediately after the resin application, effect that lasts in the long-term (six and twelve months follow-up examinations); the dental wear's progression seems to be clinically arrested. Conclusions: Resin infiltration has proven to be a minimal invasive treatment for dental discoloration, less aggressive than conventional procedures. This approach might be recommended for a stable esthetical improvement in moderate AI's lesions especially in children and adolescents.

Bonding brackets on white spot lesions pretreated by means of two methods

Objective: The aim of this study was to evaluate the shear bond strength (SBS) of brackets bonded to demineralized enamel pretreated with low viscosity Icon Infiltrant resin (DMG) and glass ionomer cement (Clinpro XT Varnish, 3M Unitek) with and without aging. Methods: A total of 75 bovine enamel specimens were allocated into five groups (n = 15). Group 1 was the control group in which the enamel surface was not demineralized. In the other four groups, the surfaces were submitted to cariogenic challenge and white spot lesions were treated. Groups 2 and 3 were treated with Icon Infiltrant resin; Groups 4 and 5, with Clinpro XT Varnish. After treatment, Groups 3 and 5 were artificially aged. Brackets were bonded with Transbond XT adhesive system and SBS was evaluated by means of a universal testing machine. Statistical analysis was performed by one-way analysis of variance followed by Tukey post-hoc test. Results: All groups tested presented shear bond strengths similar to or higher than the control group. Specimens of Group 4 had significantly higher shear bond strength values (p < 0.05) than the others. Conclusion: Pretreatment of white spot lesions, with or without aging, did not decrease the SBS of brackets.

In Vitro Progression of Artificial White Spot Lesions Sealed With an Infiltrant Resin

SUMMARY This study assessed the ability of an infiltrant resin (Icon, DMG Chemisch-Pharmazeutische Fabrik GmbH, Hamburg, Germany) to prevent artificial lesion progression in vitro when used to impregnate white spot lesions and also assessed the effect of saliva contamination on resin infiltration. Enamel specimens (n=252) were prepared and covered with nail varnish, leaving a window of sound enamel. After demineralization (pH 5.0; four weeks), specimens were divided into six groups (n=42 per group): group 1, 2% fluoride gel (positive control); group 2, resin infiltrant; group 3, resin infiltrant + fluoride gel; group 4, no treatment (negative control); group 5, resin infiltrant application after saliva contamination; and group 6, resin infiltrant + fluoride gel after saliva contamination. Specimens from each group were cut perpendicular to the surface, and one-half of each specimen was exposed to a demineralizing solution for another four weeks. The other half was set aside as a record of initial lesion depth and was used later in the determination of lesion progression. Lesion progression and infiltrant penetration were measured using confocal laser scanning microscopy (CLSM) and transverse microradiography (TMR). For lesion depth, based on CLSM, groups 2 and 3 showed the least changes when submitted to demineralization challenge, followed by group 1, then groups 5 and 6, and finally group 4. There were no significant differences between groups 2 and 3 or groups 5 and 6 in their ability to inhibit further lesion progression (p&lt;0.05). Based on TMR, groups 2 and 3 also showed the fewest changes when submitted to demineralization challenge, followed by group 5, then groups 1 and 6, and finally group 4. In terms of mineral loss as measured by TMR, all groups that contained fluoride (groups 1, 3, and 6) show less percentage change in mineral loss than the groups that did not contain fluoride (groups 2, 4, and 5). It can be concluded that infiltrant penetration into early enamel lesions inhibited further demineralization in vitro, especially in the presence of fluoride. Saliva contamination decreased the ability of the infiltrant to prevent further demineralization, but the presence of fluoride seemed to counteract this effect.