Fracture toughness of bleached enamel: Effect of applying three different nanobiomaterials by nanoindentation test

Patient Satisfaction with Resin Infiltration Treatment for Masking Noncavitated White Spot Lesions on Anterior Maxillary Teeth: Two Case Reports

Aim

We assessed patient satisfaction with resin infiltration treatment outcomes for masking postorthodontic treatment noncavitated white spot lesions on anterior maxillary teeth.

Background

White spot lesions (WSLs) are opaque white areas of demineralization. The lesion may remineralize over time, but the opaque color usually remains, retaining the undesirable tooth color. Case Description: Resin infiltration (RI) was administered to two patients with a total of 10 anterior maxillary teeth diagnosed with noncavitated WSLs. Immediately after treatment, patients were asked about their comfort during the RI treatment and their level of satisfaction with treatment outcomes. Two weeks post-treatment, the two patients were asked again about their level of treatment outcome satisfaction and if they thought they needed a second treatment. Both reported that they were comfortable during the treatment and were extremely satisfied with the achieved treatment outcomes immediately and two weeks after the treatment and did not feel that they would need to seek further treatment to reach the desired outcome.

Conclusion

Resin infiltration is a comfortable, conservative treatment option providing satisfactory outcomes in masking noncavitated WSLs on anterior maxillary teeth after orthodontic treatment. Clinical Significance. Resin infiltration is a conservative treatment option to mask noncavitated WSLs after orthodontic treatment.

The Effect of Home and In-Office Bleaching on Microhardness and Color of Different CAD/CAM Ceramic Materials

The aim of this study is to assess the effect of different bleaching agents on microhardness and color of CAD/CAM ceramics including IPS e.max CAD (lithium disilicate), VITA ENAMIC (polymer-infiltrated ceramic), and Celtra Duo CAD (zirconia-reinforced lithium silicate). Materials' samples were divided into three groups (n = 10) and each received a different bleaching treatment; 20% carbamide peroxide, 35% carbamide peroxide, and 40% hydrogen peroxide. A fourth group was stored in water acting as a control. Vickers microhardness and spectrophotometric color measurements were taken at baseline and after bleaching. IPS e.max CAD showed a significant reduction (about 14%), while VITA ENAMIC showed a significant increase (about 78%) in microhardness after bleaching (p ˂ 0.001). Celtra Duo CAD did not demonstrate a significant change in microhardness (p ≥ 0.609). The color difference (ΔE_ab) after bleaching was 0.29 (±0.08), 2.84 (±0.64), and 1.99 (±0.37) for IPS e.max CAD, VITA ENAMIC, and Celtra Duo CAD, respectively. It could be concluded that the effect of bleaching on color and microhardness was mainly material-dependent. Bleaching significantly affected the microhardness of IPS e.max CAD and VITA ENAMIC. The color difference was within the clinically imperceptible range for IPS e.max CAD, while VITA ENAMIC and Celtra Duo CAD demonstrated perceptible color change.

Effects of Different Bleaching Agents on the Surface Topography and the Microhardness of Artificial Carious Lesions

Objectives The aim of this study was to evaluate the effects of in-office and at-home bleaching agent applications on the surface topography and microhardness of artificially demineralized enamel.

Materials and Methods A total of 224 enamel specimens were prepared using bovine sound central incisors. 4 mm × 4 mm enamel windows were exposed on the buccal surfaces covering the remaining surface with nail varnish. Samples were immersed in a demineralizing solution for 16 hours to produce artificial caries lesions, then divided into four groups according to the bleaching agent’s type and concentration. Group I; in-office bleaching 35% hydrogen peroxide (HP) (Whiteness HP Maxx; FGM, Brazil), Group II and Group III at-home bleaching 16 and 22% carbamide peroxide CP, respectively (Whiteness Perfect). Group IV; control (not bleached). The microhardness Vickers hardness number (VHN) was measured at the baseline, after demineralization, and after bleaching consequently. The micro-surface changes of the enamel surface after demineralization and bleaching were evaluated by scanning electron microscope (SEM).

Statistical Analysis Data were evaluated by the one-way analysis of variance (ANOVA) test followed by Post Hoc Tukey’s and Fisher’s least significant difference. Tow- sided p -values were considered statistically significant at p ≤ 0.05.

Results A significant reduction was noticed in the enamel microhardness after demineralization p < 0.05. However, there is no statistically significant difference between the mean VHN of the demineralized and bleached enamel ( p > 0.001). SEM images showed significant changes on the surface of the demineralized enamel after bleaching (pattern type III).

Conclusions The low and high concentrations of HP and CP bleaching agents increased the demineralization severity of artificial caries lesions without significantly altering their microhardness values.

Controlled clinical trial addressing teeth whitening with hydrogen peroxide in adolescents: a 12-month follow-up

OBJECTIVES:

To evaluate the colorimetric change in incisors and canines of adolescents aged 12 to 20 years submitted to at-home whitening and to evaluate satisfaction, sensitivity and discomfort during the procedures through a questionnaire.

METHOD:

Thirty adolescents were randomly assigned to the following groups: 1) 6.0% hydrogen peroxide (White Class with calcium - FGM); 2) 7.5% hydrogen peroxide (White Class with calcium - FGM); 3) 10% hydrogen peroxide (Oral B 3D White - Oral-B); 4) Control group - placebo. Assessments were performed prior to treatment as well as at 7, 30, 180 and 360 days after treatment. Friedman's ANOVA was used to analyze color. The Kruskal-Wallis test followed by Dunn's post hoc test was used to compare the groups at the different evaluation times. Answers on the questionnaires were ranked, and non-parametrical tests were employed. The groups were compared in each period using the Kruskal-Wallis test followed by the Student-Newman-Keuls test. Categorical data were analyzed using Fisher's exact test, and the Wilcoxon test was used for the analysis of different periods. P-values were corrected using the Hyan-Holm step-down Bonferroni procedure. Clinicaltrials.gov: NCT01998386.

RESULTS:

Similar results were obtained one month after treatment with both tooth whitening gels and whitening strips. Patients were partially satisfied with the treatment after the first and second weeks and would recommend it. All products demonstrated color stability after 12 months of follow-up.

CONCLUSIONS:

The bleaching procedure was efficient, and the patients could perceive its result. Further investigations are needed to determine the effects of bleaching on young teeth.

Prevention and Treatment of White Spot Lesions in Orthodontic Patients

Decalcification of enamel, appearing as white spot lesions (WSLs), around fixed orthodontic appliances is a major challenge during and after fixed orthodontic treatment by considering the fact that the goal of orthodontic treatment is to enhance facial and dental esthetic appearance. Banded or bonded teeth exhibit a significantly higher rate of WSLs compared to the controls with no braces as fixed appliances and the bonding materials promote retention of biofilms. These lesions are managed in the first step by establishing good oral hygiene habits and prophylaxis with topical fluorides, including high-fluoride toothpastes, fluoride mouthwashes, gels, varnishes, fluoride-containing bonding materials, and elastic ligatures. Recently, other materials and methods have been recommended, including the application of casein phosphopeptides-amorphous calcium phosphate, antiseptics, probiotics, polyols, sealants, laser, tooth bleaching agents, resin infiltration, and microabrasion. This article reviews the currently used methods to manage enamel demineralization during and after orthodontic treatment and the risk factors and preventive measures based on the latest evidence.