The purpose of this study was to evaluate the effects of Coca-Cola® and Schweppes® Limón on bond strength, adhesive remnant, and microleakage beneath brackets. One hundred and twenty upper central incisor brackets were bonded to bovine incisors and divided into three groups: (1) Control, (2) Coca-Cola®, and (3) Schweppes® Limón. The teeth were submerged in the drinks three times a day for 15 minutes over a 15 day period. Shear bond strength (SBS) was measured with a universal testing machine, and adhesive remnant evaluated using image analysis equipment. Microleakage at the enamel–adhesive and adhesive–bracket interfaces was determined using methylene blue. One hundred and eight teeth were used for scanning electron microscopy to determine the effect of the drinks on intact and sealed enamel. SBS and adhesive remnant data were analysed using the Kruskal–Wallis test (P < 0.05) and microleakage using the Kruskal–Wallis and Mann–Whitney tests applying Bonferroni correction (P < 0.017). No significant differences were found in SBS and adhesive remnant between the groups (P > 0.05). Microleakage at the enamel–adhesive interface for groups 2 and 3 was significantly greater than for group 1 (P < 0.017). At the adhesive–bracket interface, microleakage was significantly greater in group 2 than in group 1 (P < 0.017) while microleakage in group 3 did not differ significantly from either group 1 or 2 (P < 0.017). The drinks produced enamel erosion, loss of adhesive and microleakage. Coca-Cola® and Schweppes® Limón did not affect the SBS of brackets or the adhesive remnant.

Objective: To test the null hypothesis that agenesis of wisdom teeth is not related with any particular craniofacial morphology. Materials and Methods: Ninety-seven patients (aged 13–19 years) were selected and divided into three groups: (1) bilateral agenesis of maxillary third molars, (2) bilateral agenesis of mandibular third molars, and (3) control group without agenesis. Presence or absence of third molars was determined using ortopantomographs. Cephalometric analysis was carried out from lateral teleradiographs, which included linear, angular, and proportional measurements. When data obtained were distributed normally it was analyzed by means of single-factor variance analysis and the Scheffé test (P < .05). When data did not show normality, the Kruskal-Wallis test (P < .05) and the Mann-Whitney test were applied using Bonferroni correction (P < .017). Multivariance discrimination analysis was also carried out. Results: Values obtained for the mandibular plain of Groups 1 and 2 were significantly lower than those of the Control Group (P =.00 and P =.00, respectively). For Group 2 lower face height was significantly less than for the control group (P =.01), whilst the mandibular arch and the articular angle were significantly greater than in the Control Group (P =.000 and P = .02, respectively). Multivariance discrimination analysis obtained a correct classification in 58.8% of cases. Conclusion: The hypothesis is rejected. Agenesis of the maxillary third molars was related to a reduced mandibular plane angle. Patients with agenesis of the mandibular third molars showed a diminished lower third and a mandibular morphology characteristic of the brachyfacial pattern.

Objective: : To evaluate in vitro the shear bond strength of brackets recycled by sandblasting with aluminum oxide particles of different sizes or reconditioned industrially after successive rebonding. Materials and Methods: : Eighty brackets were bonded and debonded sequentially three times. After the first debonding, brackets were divided into four groups: (group 1) sandblasting with aluminum oxide particles of 25 μ, (group 2) 50 μ, and (group 3) 110 μ, and (group 4) industrial recycling. Bond strength and adhesive material remaining on debonded bracket bases were evaluated for each successive debond. Results: : No significant differences were detected between the four groups following the first recycle ( P > .05). After the second recycle, bond strength was significantly greater for the industrially recycled group than the other groups ( P < .016). When shear bond strength was compared within each recycling method, the bond strength of sandblasted brackets decreased with the increase of particle size and with each recycle; for the industrially recycled group, no significant differences were detected between the three sequences ( P > .016). In the evaluation of bond material remnant, the industrially recycled group left significantly less bond material after successive recycling than the other groups did ( P < .016). Within each recycling method, the adhesive remnant decreased significantly after successive debond ( P < .016). Conclusions: : Industrial recycling obtained better results than sandblasting after three successive debondings. The brackets' shear bond strength decreased as the size of the aluminum oxide particle used for sandblasting increased and as recycling was repeated.