ABSTRACT
Background: Transforming growth factor-beta 1 (TGF-ß1) is a key morphogen in regenerative endodontics that plays a central role in regulating cellular functions. Various chelating agents have been shown to release this growth factor upon conditioning. The objective of the study was to evaluate TGF-ß1 release from the dentin matrix upon conditioning with ethylene diamine tetra-acetate (EDTA), doxycycline hydrochloride, and propolis. Materials and Methods: Forty-two human 3rd molar teeth were collected and coronal portion of the teeth was sectioned to obtain dentin blocks with dimensions 2 mm × 2 mm × 2 mm. The blocks were then randomly divided into three groups depending on the conditioning agent used; Group 1: 17% EDTA, Group 2: doxycycline hydrochloride (100 mg/mL), and Group 3: propolis (250 µg/mL). Conditioned blocks were placed in 0.5 mL of phosphate buffered saline and incubated for 1 week for quantification. Results: Highest TGF-ß1 release was noted for propolis (0.21 ng/mL), followed by doxycycline hydrochloride (0.18 ng/mL) and 17% EDTA (0.14 ng/mL). Conclusion: Doxycycline hydrochloride and propolis significantly enhanced the release of TGF-ß1 from the dentin matrix compared to EDTA (P < 0.05). No significant difference was observed between doxycycline hydrochloride and propolis (P > 0.05). Doxycycline and propolis can be used as effective alternatives to EDTA during regenerative endodontic procedures.
ABSTRACT
Background: The pursuit of esthetics and superior mechanical properties prompted the layering of Yttrium stabilized Zirconia with ceramic material. However, the bioinert nature of zirconia causes the chipping off of this ceramic layer. Selective infiltration etching (SIE) of zirconia provides good bond strength between zirconia and veneering ceramic. Materials and Methods: One hundred and fifty zirconia specimens of dimensions 5 × 5 × 10 mm were divided into 5 groups. Group 1: Air abrasion with 30 µ Al2O3 for 15 s with 0.4 bar pressure. Group 2: SIE and heat-induced maturation (HIM) as demonstrated by Abousheilb. Group 3: Sintered zirconia specimens were taken up for air abrasion followed by SIE/HIM. Group 4: Air abrasion and SIE performed on unsintered specimens followed by heat treatment at 1500°C. Group 5: Air abrasion performed on unsintered zirconia specimens followed by heat treatment at 1500°C followed by SIE/HIM. The samples were then layered with ceramic and subjected to shear bond strength (SBS) analysis. Results: The mean and standard deviation were calculated for the data. The mean SBS among the groups was compared using ANOVA. The post hoc Bonferroni test was applied to compare between the groups. The mean SBS was highest for Group 5 (47.89 ± 6.53) followed by Group 2 (34.94 ± 3.04), Group 3 (32.56 ± 6.04), Group 1 (29.12 ± 7.37), and Group 4 (27.56 ± 7.54). ANOVA test showed statistically significant differences among the groups (F = 48.86, P = 0.00). Conclusion: SIE/HIM when combined with sandblasting with appropriate heat treatment demonstrated a significant increase in bond strength. This prolongs the longevity of the restoration, thereby meeting the clinical needs.
ABSTRACT
AIM: The aim of this study was to evaluate the effect of combination of surface treatment using laser along with other modalities of surface treatment on shear bond strength of zirconia to veneering ceramic. MATERIALS AND METHODS: Milled and sintered zirconia cylinders (n = 150) were used in the study which were divided into six groups that were subjected to various surface treatments. Samples in group I were subjected to sandblasting. In group II Laser (Er: YAG) surface treatment was performed. Samples in group III were subjected to sandblasting followed by laser ablation. In group IV laser ablation was carried out followed by liner application, and samples in group V were subjected to laser ablation followed by argon plasma treatment. Instron machine was used to test the shear bond strength (SBS). One-way ANOVA and Bonferroni test were used for statistical analysis. RESULT: Samples in group III showed highest values for SBS followed by groups I, IV, and V with less SBS value for group II. CONCLUSION: Thus, the results conclude the use of combination of surface treatment using laser to be an effective modality to enhance the shear bond strength of zirconia. CLINICAL SIGNIFICANCE: Synergistic surface treatment using laser increases the bond strength of zirconia prosthesis to veneering ceramic improving its clinical longevity.
