Evaluation of bond strength of orthodontic brackets using light- and chemical-cure adhesive systems over time: An in-vitro study.

AIMS: This study aimed to evaluate the bond strength of light- and chemical-cure adhesive systems over six months. MATERIALS AND METHODS: A total of 144 sound human maxillary first and second premolars were randomly divided into six groups according to the adhesive type (i.e., Transbond XT and Unite) and evaluation time. The groups were T0 (24-h group without thermocycling), T1 (24-h group with thermocycling), T2 (1-month group), T3 (2-month group), T4 (4-month group), and T5 (6-month group). The bond strength was then measured and the data were analyzed by SPSS software (version 23) through the independent t-test and one-way ANOVA. A P value less than 0.05 was considered statistically significant. RESULTS: The results of this study showed that shear bond strength of chemical-cure orthodontic adhesive (Unite, 15.37 MPa) at all-time points was significantly 1.37 times higher than that of the Transbond XT light-cure adhesive (11.15 MPa). Moreover, shear bond strength of self-cure adhesive (Unite) 1 month after debonding showed a significant difference with the 24-h group without thermocycling (P = 0.002), 24-h group with thermocycling (P = 0.008), and 6-month group (P = 0.016). The highest shear bond strength in both adhesives was observed at one month. Furthermore, the shear bond strength of Transbond XT light-cure adhesive one month after debonding showed a significant difference with the 24-h group without thermocycling (P = 0.000) and 24-h group with thermocycling (P = 0.000), as well as with the 2-month (P = 0.008), 4-month (P = 0.000), and 6-month groups (P = 0.016). CONCLUSION: Unite self-cure adhesive compared to Transbond XT light-cure adhesive has higher bond strength and is recommended for rebonding brackets in patients with multiple rebonds.

Efficacy of Different Methods of Bone-Anchored Maxillary Protraction in Cleft Lip and Palate Children: A Systematic Review and Meta-Analysis.

INTRODUCTION: Bone-anchored maxillary protraction (BAMP) is an effective option for adolescent cleft patients with maxillary hypoplasia. Hence, this study was conducted to access the effectiveness of the many techniques of BAMP in cleft lip and palate patients. METHODS AND MATERIALS: Data was compiled through a global search of random and nonrandom studies that investigated the efficacy of various techniques of BAMP in cleft lip and palate patients. The searches were conducted in ISI Web of Science, EMBASE, Scopus, Medline, and Cochrane Central Register of Controlled Trials from the beginning until October 12, 2021. The pertinent data of the comprised studies were extracted using predetermined extraction forms. Meta-analysis results were obtained by using inverse-variance to calculate the pooled results of the outcome measures. RESULTS: Five studies were submitted for meta-analysis. The BAMP therapeutic methods investigated in the studies were facemask attached to miniplates (FM-MP) and class III elastics attached to maxillary and mandibular miniplates (C3-IE: class III intermaxillary elastic). The mean differences of A-VRP, A-N Prep., ANB, wits, overjet, and SNA landmarks indicated posttreatment was encouraging, showing maxillary protrusion, and correction of class III malocclusion. SNB landmark showed no statistically significant alterations posttreatment. Subgroup analysis of the C3-IE and FM-MP subgroups indicated that the changes in ANB, SNA, and overjet parameters in the FM-MP subgroup were more pronounced than in the C3-IE subgroup. No statistically significant differences were found when the results of these 2-treatment method were compared, except for in the overjet subgroup. CONCLUSION: After undergoing BAMP treatment, the maxilla showed a more horizontal growth, but no changes in the vertical dimension were observed and the mandible did not rotate clockwise. In addition, using facemask-miniplates was more effective in increasing overjet compared with using class III elastics with bone anchors. In conclusion, BAMP treatment is a suitable alternative for adolescents with cleft lip and palate malformation.

Facial Anthropometric Evaluation of Unilateral Cleft Lip and Palate Patients: Infancy Through Adolescence.

INTRODUCTION: Craniofacial anthropometric studies measure the differences in humans' craniofacial dimensions. The aim of this study was to determine facial anthropometric dimensions of newborn to 12-year-old girls with nonsyndromic unilateral cleft lip and palate (UCLP). METHODS: In this cross-sectional analytical study, data was collected from 65 infant to 12-year old girls with UCLP. Digital frontal and profile facial photographs were transferred to a computer and desired anthropometric landmarks were traced on each image. Fifteen anthropometric parameters were measured which were the angles of facial, nasofacial, nasomental, Z, nasolabial, inclination of nasal base and labial fissure, nasal deviation, mentocervical, facial convexity and also ratios of nasal prominence relative to nasal height, middle to lower facial third, upper lip to lower lip height, columellar length relative to upper lip, and incisal show relative to incisal width. Pearson coefficient and linear regression were used for statistical analysis. RESULTS: Upper lip to lower lip height ratio and angles of nasofacial, nasolabial, and facial convexity decreased with the age of the patients. In contrast, nasomental angle and the ratios of columellar length to upper lip length, middle facial height to lower facial height, and incisal show relative to incisal width increased. Other parameters studied did not appear to have any significant correlation with age. CONCLUSION: In the girls with UCLP, various craniofacial dimensions have different growth rates with some parts growing slower than others. Some of the parameters studied were significantly correlated with age, thus growth-related curves and equations were obtained and presented.