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Aim: To evaluate the possible cytotoxic damage to the oral mucosal cells in healthy patients undergoing orthodontic treatment with clear aligners. Materials & Methods: 20 patients who required orthodontic treatment were chosen. The rst set of aligners were fabricated for each patient using a PETG material. Patients were instructed to wear the aligners for 22 hours a day for 15 days. Buccal mucosal cells were sampled at two time intervals T0- pre treatment and T1- after 15 days and were immediately smeared onto a clean glass slide. The smears were immediately xed in isopropyl alcohol, following which the slides were hydrated with distilled water, stained with the Papanicolaou method and subjected to cytomorphometric analysis. The two samples obtained at T0 and T1 for each patient were compared to check for an increase in number of micronucleated cells. Student Paired t Test was used to compare the mean micronuclei count between pre and post treatment. Results: The mean Micro Nuclei count in the post treatment period was signicantly higher (4.50 ± 1.96) as compared to pretreatment period (3.10 ± 1.73) with a mean difference of -1.40 at P=0.007. Conclusion: Within the experimental limits of this study the PETG material used for fabrication of aligners resulted in a change in the nature of buccal mucosal cells with an increase in the number of micronuclei which is an indicator for cytotoxicity. The PETG material may have a cytotoxic effect on the cells of the oral mucosa.

Study models accurately represent the teeth, their supporting tissues and the relationship between upper and lower teeth in centric occlusion. They contribute greatly to diagnosis and treatment planning, to compare pre-and post-treatment changes and are valuable instructional and illustrative aids during consultation with patients. [1] Accurate trimming of orthodontic study models facilitates proper diagnosis and treatment planning. Well-trimmed, esthetically pleasing models, reflect the practitioner's attention to detail and are a part of the patient's legal treatment record. [2,3] American board of orthodontics prescribes certain specifications for plaster study models for universal acceptance. [4]

Aim To evaluate and compare shear bond strength (SBS) and debonding characters of the Transbond XT (BisGMA-based composite), Esthet-X flow (flowable composite), Filtek Z-350 (flowable composite). Materials and methods A total of 90 human premolars were divided into group I, Transbond XT (n = 30); group II, Esthet-X flow (n = 30) and group III, Filtek Z-350 (n = 30), the preadjusted edgewise stainless steel premolar brackets were bonded to evaluate the shear bond and debonding properties. Results The results of the statistical analysis comparing the three groups indicated no statistically significant differences between the groups. In general, the SBS with groups I and III exhibited similar bond strength with 11.58 ± 1.3 MPa and 11.07 ± 1.0 MPa respectively. Groups III exhibited least bond strength of 10.7 ± 2 MPa. In modified adhesive remnant index (ARI) the majority of bond failures occurred at enamel-adhesive interface or cohesive type failure in all the three groups. Groups II and III showed increased frequency of score 2, 4 and 5 compared to group I which showed increased frequency of score 0 and 1. Conclusion When considering the SBS and ARI scores obtained, flowable composites can be effectively applied to orthodontic bracket bonding. How to cite this article Pradeep S, Shanthraj R, Kiran HJ, Shivalinga BM. Comparative Evaluation of the Shear Bond Strength and Debonding Properties of a Conventional Composite and Flowable Composites used for Orthodontic Bracket Bonding. World J Dent 2013;4(1):6-16.

This article describes a template which can be used for stabilizing the archwire during the soldering of the hook on archwires for retraction. This permits hands free operation and decreases the chances of incorrect positioning and annealing of the bare archwire.