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Introduction: Orthodontic adhesives should possess adequate bond strength and biocompatibility. Inadequate bond strength may lead to bond failures, and if the adhesive is not biocompatible, it may result in allergic reactions. Therefore, it is of prime importance to study the cytotoxicity and Shear Bond Strength (SBS) of commercially available orthodontic materials. Aim: This study aimed to comparatively evaluate in-vitro cytotoxicity, the Adhesive Remnant Index (ARI), and SBS of various orthodontic adhesives. Materials and Methods: This in-vitro study was conducted in an institutional setting as a collaborative effort between the Department of Orthodontics and White Lab-Blue Lab at Saveetha Dental College and Hospital, Chennai, India, from July 2023 to August 2023. Forty extracted human premolar teeth were bonded with four different ARI adhesives (U Bond, Enlight, Transbond XT, Aqualine LC) (n=10/group) and mounted on acrylic blocks. They were evaluated for SBS using a Universal Testing Machine (UTM), ARI using Scanning Electron Microscopy (SEM), and cytotoxicity using the MTT {3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide} assay on Human Gingival Fibroblast Cells (HGFC). Statistical analysis was performed using One-way ANOVA, with a post-hoc test for pairwise comparison to evaluate the SBS values, and the Kruskal-Wallis Test to analyse ARI inter group scores and cytotoxicity levels. Statistical Package for the Social Sciences (SPSS) software (Version 23.0) was used to conduct the statistical tests. Results: Significant differences in SBS values (p=<0.001) and ARI scores (p=<0.001) were noted between the different adhesives. No significant difference (p-value=0.534) in cytotoxicity was observed among all adhesives, with all exhibiting acceptable levels of biocompatibility. Conclusion: Primer-based adhesive (Transbond XT) demonstrated the highest SBS and ARI scores among the various orthodontic adhesives, with acceptable levels of biocompatibility. No significant difference was found between the conventional primer-based adhesive (Transbond XT) and the Single Component Adhesive (SCA) (Aqualine LC). Therefore, this study advocates for the use of SCA in routine clinical practice. [ABSTRACT FROM AUTHOR]

Aims: The aim of this in vitro study was to evaluate the color changes in the retainers by different manufacturers (Essix ACE, Forestadent, Leone, and Bioart) after exposure to various beverage solutions (coke, tea, coffee, and artificial saliva) and also to assess the stain removal potential of different cleansing agents [listerine (L) and retainer brite (RB)]. Materials and Methods: A total of 320 specimens (80 samples in each group) of thermoformed retainers from four different manufacturers were tested. All retainers were thermoformed and were immersed in different beverages (black tea, coffee, and cola) and artificial saliva as a control group for 7 and 14 days. These were then cleaned by either L or RB crystals. The color changes (ΔE) in several retainers were assessed following a 7-day exposure (T1-T0), a 14-day exposure (T2-T0), and following cleaning (T3-T1 and T3-T2). The CIELAB color space approach was utilized to obtain the ΔE measurements. To statistically evaluate the data, t test, analysis of variance, Tukey's range test, and Levene's test were employed. Results: On intragroup comparison, all groups were stained by tea with significant differences at 7 and 14 days (P < 0.05). Significant differences in color change after cleaning by L at the 7-day interval (P < 0.05) were noted in group A for immersion in cola. No significant difference was noted for groups B and C (P > 0.05). Significant differences in color change after cleaning with RB for tea stains in group D (P < 0.05) were noted. Significant intergroup differences in staining were noted for tea at 7- and 14-day intervals (P < 0.05) with maximum staining in group D. For coffee, significant intergroup differences were noted with maximum staining in group A (P < 0.05) at both 7- and 14-day intervals. Significant intergroup differences in cleaning were noted at the 12- h interval in group A for tea stains by RB (P < 0.05) and cola stains by L (P < 0.05). Conclusions: Tea exhibited the greatest staining potential among all staining agents at 7-and 14-day intervals for Forestadent, Leone, and Bioart retainers, while coffee stained Essix ACE retainers the most. Among the four different retainer brands, Bioart exhibited the least staining with the various staining agents at 7- and 14-day intervals. RB eliminated tea stains better, whereas cola and coffee stains were better removed by L. [ABSTRACT FROM AUTHOR]

This review aims to collate and analyze the existing evidence on the comparison of external apical root resorption (EARR) in subjects treated with clear aligners (CAs) and fixed appliances (FA). An electronic search was conducted in six databases for articles published in all languages until July 2023. Studies that evaluated EARR in subjects treated with CAs and FAs were included. The RoB 2 tool for RCTs and the ROBINS-I tool for non-randomized studies were used to analyze the risk of bias (ROB). A random effects meta-analysis was performed to assess EARR extent in maxillary and mandibular anterior teeth for subjects treated with CAs and FAs. Ten studies (eight retrospective, one RCT, and one CCT) were included in this review, out of which six studies reported a moderate ROB, one reported a serious ROB, and three reported a low ROB on qualitative analysis. The quantitative analysis of six studies revealed a significant intergroup difference (P <0.05)> P <0.00001)> P =0.01) with a moderate heterogeneity (I2=56%), as well as the mandibular central incisors (SMD=-0.27, P =0.04) with high heterogeneity (I2=79%). EARR was lower in subjects treated with CAs than FAs. A moderate quality of the available evidence suggests that EARR was less evident in subjects treated with CAs when compared with FAs. [ABSTRACT FROM AUTHOR]

Background: Single-component adhesives do not require the application of a primer on the enamel surface that has been etched and has been reported to have acceptable shear bond strengths on in vitro evaluation. Aim: This split-mouth study aimed to examine and assess the rates of bracket bond failure of hydroxyethyl methacrylate (HEMA)-based (Aqualine LC) and bisphenol A-glycidyl methacrylate (BisGMA)-based (Orthofix SPA) single-component adhesives used to bond orthodontic brackets over 6 months. Materials and Methods: This in vivo study involved the participation of 50 adult subjects, with 1080 metallic brackets directly bonded to the labial/facial surface in a split-mouth design. After 6 months of treatment, 49 patients with 490 brackets bonded using a HEMA-based adhesive and 490 brackets bonded using a BisGMA-based adhesive were evaluated for bracket bond failures. Descriptive statistics and chi-square tests were done to compare the results. Results: The overall bracket bond failure rate (BFR) with single-component adhesives was 6.02%. Bracket BFRs of HEMA-based and BisGMA-based adhesives were 4.16% and 7.8%, respectively, and the difference was statistically significant (P < 0.05). Significant differences in BFRs between maxillary teeth (4.28%) and mandibular teeth (7.75%) were noted (P < 0.05). No significant differences in bond failures between either side or region were noted. Conclusion: Bond failures were more in brackets bonded with BisGMA-based adhesive (Orthofix SPA) compared with HEMA-based adhesive (Aqualine LC). Bond failures were less in the maxillary arch. [ABSTRACT FROM AUTHOR]

Introduction: Adequate bond strength between orthodontic brackets and enamel is necessary to withstand masticatory forces. Priming involves applying a primer before using the adhesive as a separate step. To reduce bonding time, manufacturers have introduced self-priming adhesives. Aim: To evaluate the Shear Bond Strength (SBS) and Adhesive Remnant Index (ARI) scores of a Bis-GMA based self-priming adhesive (Orthofix SPA, Anabond) and compare it with a 2-Hydroxyethyl Methacrylate (HEMA) based self-priming adhesive (Aqualine LC, Tomy ortho) and a Bis-GMA containing primer-based orthodontic adhesive (Transbond XT, 3M). Materials and Methods: The present In-vitro study was conducted at the White Lab., Saveetha Dental College and Hospitals, Chennai, Tamil Nadu, India, from December 2020 to January 2021. A total 54 freshly extracted premolar teeth were collected and divided into three groups (Group A - Orthofix SPA, Group B - Transbond XT, and Group C - Aqualine LC) based on the adhesive used. A 0.022 metal orthodontic brackets were bonded, and SBS and ARI scores of the samples were assessed. The Shapiro-Wilk test for normality was conducted. One-way Analysis of Variance (ANOVA) was used to compare the mean and standard deviation of SBS values and ARI scores among the three groups, and a post-hoc Tukey test was performed for inter group comparisons. Results: Significant inter group differences were observed (p=0.004). Group A had lower SBS than Groups B and C. Significant inter group differences (p-value of 0.003) in ARI scores were noted, with Group A having the lowest scores. Conclusion: The Bis-GMA self-priming adhesive (Orthofix SPA) exhibited lower SBS and ARI scores compared to commercially available HEMA-based self-priming adhesive systems and primer-based Bis-GMA adhesive systems. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Anterior‑posterior discrepancy assessment is a crucial component of orthodontic diagnosis and is often carried out using hard tissue cephalometric analysis. The purpose of this study was to compare the photographic Frankfort plane subnasale pogonion (FSA) angle with established cephalometric parameters to determine the accuracy of the angle in determining maxillomandibular anteroposterior discrepancies. MATERIALS AND METHODS: In this prospective study, a total of 60 subjects, 20 in each skeletal sagittal malocclusion, were included in the final sample based on the selection criteria. Both photographic and cephalometric records were taken, and the parameters assessed were the beta angle, Steiner’s analysis, the ANB (A point‑ Nasion‑ B point) angle in the cephalograms, and the FSA angle in the profile photographs. Statistical analysis was done with SPSS software. The correlation between the measured parameters was assessed using Pearson’s correlation test. RESULTS: A high positive and significant correlation between the FSA angle and beta angle (r = 0.793) was noted, and a high negative and significant correlation between the FSA angle and ANB angle (r = ‑0.848) was noted. CONCLUSION: The photographic FSA angle can be used as a reliable parameter to diagnose anteroposterior discrepancies. [ABSTRACT FROM AUTHOR]

Aim: Enamel demineralization around orthodontic brackets due to the formation of cariogenic biofilms can be prevented by modifying the adhesive/primers with certain antimicrobials. The aim of this study was to evaluate the antimicrobial, cytotoxic, and mechanical properties of a novel chitosan-modified (CH) orthodontic primer and compare it with a control primer. Materials and Methods: This in-vitro study involved two groups (Group A: CH-modified primer and Group B: control primer). Antibacterial properties against Streptococcus mutans were evaluated using the agar well-diffusion technique to measure the zone of inhibition, and minimum inhibitory concentration (MIC) was evaluated using the two-fold diffusion technique. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) fibroblast assay was done to evaluate the cytotoxicity. After bonding brackets on extracted natural teeth the shear bond strength (SBS), contact angle (CA), and adhesive remnant index (ARI) were evaluated for both groups. Statistical analysis was done using SPSS software and the independent t-test and Mann–Whitney test were performed. Results: The CH primer when compared to the control primer had higher zone of inhibition values and lower MIC value. MTT fibroblast assay showed that the cell viability percent shown by the CH primer was more in comparison to the control primer. Statistically nonsignificant differences were found between the two primers for SBS (P > 0.05), CA (P > 0.05), and ARI (P > 0.05). Conclusion: The CH primer showed higher antibacterial activity against S. mutans at a lower inhibitory concentration, with less cytotoxicity with no effect on the SBS, CA, and ARI scores. [ABSTRACT FROM AUTHOR]

Aim and Objective: The aim of the study was to compare the full-depth bone thickness and the cortical bone thickness in the infrazygomatic crest (IZC) region above the mesiobuccal (MB) root of maxillary first molar and second molar and thus find the ideal site for the placement of IZC screw. Materials and Methods: Pretreatment cone-beam computed tomography images of 30 orthodontic patients were collected and IZC bone thickness and cortical bone thickness were measured above the MB root of maxillary first and second molar at an angle of 70° to the molar occlusal plane. Measurements were done on both right and left sides. Independent sample t test was done to compare the bone thickness between the right and left sides and also to compare the bone thickness above the first and the second molar. Results: Mean bone thickness at the IZC region of 5.48 ± 2.2 mm and 7.78 ± 2.35 mm and a cortical bone thickness of 2.24 ± 0.46 mm and 2.13 ± 0.46 mm was obtained above the MB root of maxillary first molar and second molar, respectively. IZC bone thickness was significantly higher above the second molar than above the first molar (P <.001), whereas there was no significant difference in the cortical bone thickness measured on both the sites (P =.22). Conclusion: Significantly higher IZC bone thickness was noted above the MB root of the maxillary second molar, which may ensure better stability and safety of the miniscrew. [ABSTRACT FROM AUTHOR]