Evaluation of Antimicrobial and Mechanical Properties of a Novel Propolis-Modified Orthodontic Primer: An In-Vitro Study.

Introduction Accumulation of cariogenic biofilm around the bracket surface and the enamel adhesive interface leads to the formation of white spot lesions which poses an arduous challenge in orthodontics today. The aim of this study was to do a comparative evaluation of the antimicrobial, cytotoxic and mechanical properties of a novel propolis-modified orthodontic primer with a control primer. Materials and methods This in-vitro study involved two groups (group A: propolis-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 mic was evaluated using the two-fold diffusion technique. 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) fibroblast assay was done to evaluate the cytotoxicity. After bonding brackets on extracted natural teeth (premolars) the shear bond strength (SBS), contact angle (CA) and adhesive remnant index (ARI) were evaluated for both groups. Statistical analysis was done using Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 23.0, Armonk, NY), and an independent t-test was performed. Results The propolis-modified primer when compared to the control primer had higher zone of inhibition values and lower minimum inhibitory concentration (MIC) values. The MTT fibroblast assay showed that the cell viability % shown by the propolis primer was more than the control primer. There was no statistically significant difference between the two primers for SBS (p>0.05), CA (p>0.05) and ARI (p>0.05) (p=0.05). Conclusion The propolis-modified primer showed higher antibacterial activity against S. mutans at a lower inhibitory concentration, with less cytotoxicity and no effect on the SBS, CA and ARI scores.

Prevalence and extent of Alveolar dehiscence and fenestration in Class I hyperdivergent subjects with different buccolingual inclinations of maxillary molar teeth: a CBCT study

Buccolingual position of teeth could affect the prevalence of alveolar bone defects. Presence of alveolar defects may have a deleterious effect on orthodontic treatment. The aim was to assess the prevalence and extent of dehiscence and fenestration in Class I hyperdivergent subjects and correlate it with buccolingual inclinations(BL) of maxillary first molar teeth. Methods: This retrospective study involved 80 CBCTs of class I hyperdivergent subjects divided into two groups - group A (n=33) buccolingual inclination >9º and group B (n=47) buccolingual inclination <9º. Prevalence and extent of alveolar bone dehiscence and fenestrations were measured in CBCTs using OSIRIX Lite software. Descriptive statistics, Mann Whitney U test and Spearman correlation were done for evaluating intergroup differences and correlation with Buccolingual inclination. Results: Overall prevalence of dehiscence and fenestration in maxillary first molars was 60.95% and 5% respectively. In the buccal alveolar bone, prevalence of dehiscence was highest in group A (84.6%) for 16 and in the lingual alveolar bone prevalence of dehiscence was highest in group B (71.4%) for 26 . On intergroup comparison, the extent of lingual alveolar bone dehiscence (26) in group B was significantly higher (p value <0.05) than in group A. No significant correlation between the extent of dehiscence and fenestration with buccolingual inclination of molar teeth was noted. Conclusion: Molar teeth with BL inclinations of more than 9º had higher prevalence of dehiscence on the buccal side and molar teeth with BL inclinations less than 9 degrees had more dehiscence on the lingual side. But no significant correlation of BL inclination with prevalence and extent of dehiscence and fenestration was noted

Occlusal Contact Surface Changes and Occlusal Force Distribution Between Vacuum-Formed Retainers and Other Retainers: A Systematic Review.

The present systematic review was done to assess the available literatures on changes in the number of occlusal contacts (NOC), occlusal contact surface areas, and occlusal force distribution (OFD) with vacuum-formed retainers (VFRs) or clear overlay retainers during retention and to compare them with other retainers. Six electronic databases (Web of Science, Scopus, PubMed, Cochrane Library, Lilacs, and Google Scholar) were searched. Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) reporting on occlusal contact changes with VFRs were included. A total of nine articles were included in this review: three RCTs, five prospective controlled trials (PCTs), and one CCT. The Cochrane risk of bias tool and ROBINS-I tool were used for risk of bias assessment. The three RCTs showed moderate risk of bias, and out of five CCTs, four showed low risk of bias, and one showed moderate risk of bias. One CCT showed a low risk of bias in the ROBINS-I tool. Two out of four studies reported improved occlusal surface area (OSA) with VFRs when assessed at the end of six months and 12 months; one out of four studies reported improved NOC; and one study reported a decrease in OFD anteriorly and an increase in OFD posteriorly after two months of retention. On comparison between the groups, the other retainer groups showed more NOCs compared to VFRs. The limited available evidence suggests an increase in OSA and no change in NOCs and OFD with VFRs during retention. No significant differences between VFRs and other retainers for OSA and OFD were noted, and more NOCs were noted for other retainer groups.

An in vitro comparative evaluation of surface roughness characteristics of different orthodontic archwires: An atomic force microscopy study.

Background. The present study evaluated and compared the surface roughness (SR) of five different types of orthodontic archwires made by two different manufacturers. Methods. In this in vitro study, 10 samples of five different archwires comprising of three types of shape memory wires, SmartArch (Ormco), Damon (Ormco), Heat-activated NiTi (HANT) (G&H Orthodontics), Stainless Steel wire (SS) (Ormco), and conventional NiTi (G&H Orthodontics) were examined by atomic force microscopy (AFM). The processing of 3D images was carried out using Gwyddion software, from which the root mean square (rms), the roughness average (Ra), and the maximum height (mh) of the scanned surface profile were documented. The data were analyzed with one-way ANOVA followed by post hoc Tukey tests for intergroup comparisons. Results. The mean SR of SS wires was the least (Ra=8.70±0.17), followed by NiTi wires (10.29±2.00) with a significant difference between them (P<0.05). Among the three shape-memory wires, the HANT wires had the least SR (Ra=22.97±16.56) compared to SmartArch wires (Ra=25.55±3.78) and Damon wires (Ra=25.67±4.54), but the difference was not significant (P>0.05). Conclusion. The SS wires by Ormco had the least SR followed by G&H orthodontics NiTi wires. The three different shape-memory wires tested had no significant difference in SR values.

Correlation between chronological age and skeletal age using cvmi and modified MP3 methods.

Chronological age conveys only a rough approximation of the maturational status of a person whereas skeletal maturity indicators give a more accurate estimation. Therefore, it is of interest to document the correlation between chronological and skeletal age using CVMI and modified MP3 methods. A total of 39 subjects between the age ranges of 9-16 years were selected for this study. Pre-treatment lateral cephalograms and hand-wrist radiographs of the subjects were used. The skeletal age was analyzed by the Cervical Vertebrae Maturity Index (CVMI) and modified MP3 methods. The data was analyzed with SPSS software version 23.00. Kendall's Tau correlation test was performed to estimate the correlation between chronological age and skeletal age among the subjects and a linear regression test was also performed. Positive correlation was found between chronological age and skeletal age assessed by CVMI method (r= 0.398) and modified MP3 method (r=0.382) with p value >0.003. Thus it can be concluded that there was a positive correlation between chronological age and skeletal age among all the subjects.