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Background: By increasing the number of adults seeking orthodontic treatment bonding orthodontic brackets to the surfaces other than intact enamel has become necessary. The purpose of this study was to evaluate the effect of three different surface preparation methods associated with orthodontic bonding on porcelain color alteration. Materials and Methods: In this in vitro study forty-five porcelain discs (6- mm diameter, 2- mm thickness) were fabricated. The color of the specimens was evaluated by means of a Vita Easyshade. Commision Internationale de I'Eclairage (CIE) L* a* b* system was used for color measurement. Then, the specimens were randomly divided into three groups (n = 15) with respect to the surface preparation methods including a 9.6% hydrofluoric acid (HF) + silane, sandblasting, and sandblasting + 9.6% HF + silane. Metal orthodontic brackets were bonded. Samples were stored in 37° c water for 24 hours. Afterward, the brackets were debonded with a debonding plier and porcelain surfaces were polished with a tungsten-carbide bur. The color assessment was done, and ΔE values were measured. ΔE = 3.7 units were considered as an acceptability threshold. Data were analyzed with Paired t-test and one-way ANOVA. Level of significance was set at P < 0.05. Results: Orthodontic bonding changed the color parameters significantly. Mean L*, a* and b* difference were 1.35 ± 2.41, 0.19 ± 0.80, 0.89 ± 1.27 units, respectively (P = 0.003 for L*, P < 0.001 for a* and b*). There was not any significant difference in ΔE units between the groups (P = 0.456). In all the groups the mean ΔE values were below 3.7 units and within the clinically acceptable limit. Conclusion: Orthodontic treatment changed the CIE color parameters of porcelain surface. However, the color alteration is below the clinically acceptable threshold. With regard to color alteration, there is no difference between different surface conditioning methods. [ABSTRACT FROM AUTHOR]

Introduction: Although nickel and chromium are known as allergen and cytotoxic orthodontic metals, very few and controversial studies have assessed the effect of orthodontic treatment on their systemic levels especially those reflected by their best biomarker of exposure, hair. Additionally, metal injection moulding (MIM) brackets are not studied, and there is no study on systemic ion changes following their usage. Methods: In this double-blind randomized clinical trial, scalp hair samples of 24 female and 22 male fixed orthodontic patients [as two groups of conventional (two-piece) versus MIM brackets, n = 23 × 2] were collected before treatment and 6 months later. Randomization was carried out using a computer-generated random number table. The patients, laboratory expert, and author responsible for analyses were blinded of the bracket allocations. Hair nickel and chromium levels were measured using atomic absorption spectrophotometry. The effects of treatment, bracket types, gender, and age on hair ions were analysed statistically (a = 0.05, ß ≤ 0.02). Results: In both groups combined (n = 46), nickel increased from 0.1600 ± 0.0890 µg/g dry hair mass (pre-treatment) to 0.3199 ± 0.1706 (6th month). Chromium increased from 0.1657 ± 0.0884 to 0.3066 ± 0.1362 µg/g. Both of these increases were significant (paired t-test, P = 0.0000). Bracket types, age, and gender had no significant influence on ion levels (P > 0.05). ANCOVA indicated different patterns of chromium increases in different genders (P = 0.033) and ages (P = 0.056). Limitations: Sample size determination should have accounted for the grouping as well. Conclusion: Hair nickel and chromium levels might increase about 185-200% after 6 months. They might not be affected by bracket types. Gender and age might not influence the baseline or 6thmonth levels of both metals. Gender might however interact with orthodontic treatment, only in the case of chromium. Registration: The research is registered offline (thesis) and online (IR.AJUMS.REC.1394.516). Protocol: The protocol was pre-determined before any experiments begin. Funding: The study was self-funded by the authors. [ABSTRACT FROM AUTHOR]

Background: Odontogenic keratocyst (OKC), also called keratocystic odontogenic tumor (KCOT), is a developmental lesion which should be carefully monitored and it exhibits development mechanisms and biologic behaviors different from those of other more common lesions such as dentigerous and radicular cysts. CD10 antigen is a cell surface metalloendopeptidase, which inactivates various peptides that are physiologically active. Studies have shown that increase in the expression of CD10 in the stromal cells helps the progression of the tumor. Ameloblastoma (AB) is a local invasive tumor and given the role of supporting connective tissue stroma in the aggression and progression. The aim of the present study was to comparatively evaluate the expression of CD10 in the connective tissue stroma of AB and OKC as a KCOT. Materials and Methods: In this retrospective, cross‑sectional study, 14 paraffin blocks of KCOT and 9 of AB (7 multicystic and 2 unicystic) were evaluated with CD10 immunohistochemical expression in the connective tissue stroma of AB and the connective tissue wall of KCOT. The data were analyzed with Fisher's exact test (P < 0.05). Results: In 8 samples of 9 AB and in 13 samples of 14 KOT lesions, expression of CD10 was shown. Fisher's exact test did not reveal any significant differences between these two lesions in the expression of CD10 (P = 0.64). Conclusion: The results of this study propose that high expression rate of CD10 might be one of the reasons for the aggressive behavior of AB and high recurrence rate of OKC and reinforce the classification of OKC as an odontogenic tumor. [ABSTRACT FROM AUTHOR]