Efficacy of Er, Cr: YSGG laser phosphoric acid gel and Riboflavin activated by Photodynamic therapy on enamel reconditioning rebonded to metallic brackets: An Invitro study

Orthodontic Bracket to Enamel Pretreated With Nd: YAG and Er: Cr, YSGG Lasers Using Curcumin-Hydroxyapatite Nanoparticles Infused Adhesive: A FTIR, SEM Evaluation via Backscattered Electron Imaging

To evaluate the SBS, DC, and rheological valuation of experimental 1 wt % Cur-loaded-HNPs orthodontic adhesive to bond bracket to enamel surface treated with PA; Nd: YAG, and Er: Cr, YSGG lasers. Two adhesives were prepared experimental adhesive (EA) and EA loaded with 1-wt % Cur-HNP. Surface characterization of Cur-loaded HNP was performed under SEM along with EDS. Specimens were prepared and conditioned with three different strategies PA-gel, Er,Cr:YSGG laser, Nd: YAG laser. Following pretreatment brackets were bonded, samples underwent artificial aging and two samples from each enamel pretreatment regime were assessed under SEM via BSE. SBS testing was achieved via UTM followed by failure analysis using ARI. Modified and unmodified adhesives underwent DC using FTIR and rheological valuation was performed. SBS and DC were assessed using ANOVA and post hoc multiple comparison tests. The highest SBS was seen in the enamel surface treated with PA. The lowest SBS was remarked in the enamel surface treated with Nd: YAG laser. Based on ARI it was noted that modified adhesive containing Cur-HNP exhibited the highest number of failures between 1 and 2. No significant difference was observed between both adhesives in terms of DC. Adhesive modified with 1% Cur-HNP increased viscosity with a decrease in fluidity. The use of Er,Cr:YSGG laser for enamel pretreatment before bracket placement showed potential as a substitute for conventional acid etching, especially when combined with an experimental orthodontic adhesive containing Cur-HNPs.

Pretreatment of enamel with Riboflavin activated photodynamic therapy and Er, Cr: YSGG laser for bonding of orthodontic bracket with adhesive modified with cerium oxide nanoparticles

AIM

To assess the degree of conversion (DC) and shear bond strength (SBS) of experimental adhesive (EA) infused with and without 1 % Cerium oxide (CeO₂)-NPs on metallic bracket bonded to enamel conditioned with three different pretreatment regimes PDT-activated (Riboflavin) RF, ECY (Er, Cr: YSGG), and Phosphoric acid (PA).

MATERIAL AND METHOD

EA and EA modified with 1 % CeO₂-NPs were prepared. Characterization of CeO2NPs was assessed using a scanning electron microscope (SEM). Seventy-two premolars extracted due to periodontal or orthodontic reasons were disinfected. Samples were mounted and allocated into three groups according to enamel surface treatment before bracket bonding. Samples in Group 1 were pretreated with Traditional 37 % PA-gel; Specimens in Group 2 surface treated with RF-activated PDT, and samples in Group 3 were conditioned using ECY. Brackets were placed on conditioned surfaces and samples were aged and underwent SBS testing using UTM. ARI index was used to assess bond failure. DC was evaluated for both adhesives using FTIR. ANOVA and Tukey post hoc test were used to compare the means and standard deviation (SD) of SBS and DC in different experimental groups.

RESULTS

Enamel conditioned with PA and RF activated by PDT demonstrated comparable bond values with 1 % CeO2 infused in EA and EA (p>0.05).ARI analysis shows that enamel conditioned with PA and RF activated by PDT showed the majority of failure types between 1 and 2 irrespective of the type of adhesive. DC value in EA (73.28±8.37) was the highest and comparable to 1 % CeO2 infused in EA (66.48±6.81) CONCLUSION: RF-activated PDT can be used alternatively to 37 % PA for enamel conditioning when bonding metallic brackets. Infiltration of 1 % CeO2 NPs in EA improves SBS irrespective of the type of enamel conditioning. Infusion of 1 % CeO2 NPs in EA demonstrates no significant difference in DC compared to EA.

Conditioning of PEEK Implant Abutment Surfaces Using Photodynamic Therapy, Nd:YAG Laser, and Conventional Methods to Evaluate Shear Bond Strength

Objective: This study was done to evaluate shear bond strength (SBS) and modes of failures after different surface treatment modalities on polyetheretherketone (PEEK) implant abutments. Materials and methods: Seventy-five PEEK implant abutment specimens were randomly distributed into five groups based on surface treatment methods: Group I: No treatment, Group II: methylene blue-mediated photodynamic therapy (MB-PDT), Group III: neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, Group IV: Sulfuric acid (H2SO4), and Group V: Sandblasting (Sb). The measurements for SBS and failure modes for PEEK implant abutment specimens were evaluated via Universal Testing Machine and Stereomicroscope, respectively. Two-way analysis of variance and Tukey's post-hoc test (p > 0.05) were used for the statistical analysis. Moreover, the Shapiro-Wilk normality test was also performed for normality. Results: The SBS mean values and standard deviations in megapascals (MPa) for PEEK abutment specimens with different surface pretreatment groups are shown in Table 1 and Fig. 1. The control group had the lowest SBS (9.67 ± 2.1 MPa), while the highest SBS was observed in Group II (MB-PDT; 17.21 ± 1.32 MPa). SBS values for Group IV (H2SO4; 15.83 ± 0.63 MPa) and Group III (Nd:YAG laser; 16.91 ± 2.10 MPa) were similar to Group II (MB-PDT; p > 0.05). The SBS values for the sandblasted specimens (13.90 ± 1.87 MPa) were not significantly different from the control group (p > 0.05). Conclusions: The PEEK implant abutment surfaces treated with MB-PDT and Nd:YAG laser expressed significantly improved SBS.