Microimplant assisted rapid palatal expansion vs surgically assisted rapid palatal expansion for maxillary transverse discrepancy treatment.

INTRODUCTION: This study compared the skeletal and dental changes of microimplant assisted rapid palatal expansion (MARPE) with those produced by surgically assisted rapid maxillary expansion (SARPE) in postpeak adolescents and adults. METHODS: The sample comprised 17 patients (mean age, 26 ± 11 years) selected for the MARPE group and 15 (mean age, 28.5 ± 10.5 years) selected for the SARPE group. Cone-beam computed tomography scans taken just before and after the expansion were used to assess dental and skeletal changes and compare the changes between the groups. RESULTS: MARPE showed greater transversal skeletal changes in the midface and posterior and anterior maxillary base measurements. The transverse displacement of the alveolar process was greater but not significant for the SARPE group than the MARPE group. Regarding dental effects, the root distance measurements did not differ between the groups, but SARPE produced a significantly greater increase in intermolar and interpremolar distance and a greater buccal inclination of the alveolar process and supporting teeth than MARPE. CONCLUSIONS: The MARPE technique showed an increase in skeletal transverse maxillary expansion at the midface and basal bone compared with SARPE, especially at the posterior palatal region; however, no difference was found in the expansion of the alveolar process between the 2 methods. MARPE presented a more parallel expansion in both a coronal and axial view, whereas SARPE led to a V-shaped opening. The greater buccal inclination of the alveolar process and supporting teeth was observed in the SARPE group.

In vitro study of color stability of polycrystalline and monocrystalline ceramic brackets.

OBJECTIVE: The aim of this in vitro study was to analyze color stability of monocrystalline and polycrystalline ceramic brackets after immersion in dye solutions. METHODS: Seven ceramic brackets of four commercial brands were tested: Two monocrystalline and two polycrystalline. The brackets were immersed in four dye solutions (coffee, red wine, Coke and black tea) and in artificial saliva for the following times: 24 hours, 7, 14 and 21 days, respectively. Color changes were measured by a spectrophotometer. Data were assessed by Multivariate Profile Analysis, Analysis of Variance (ANOVA) and Multiple Comparison Tests of means. RESULTS: There was a perceptible change of color in all ceramic brackets immersed in coffee (ΔE* Allure = 7.61, Inspire Ice = 6.09, Radiance = 6.69, Transcend = 7.44), black tea (ΔE* Allure = 6.24, Inspire Ice = 5.21, Radiance = 6.51, Transcend = 6.14) and red wine (ΔE* Allure = 6.49, Inspire Ice = 4.76, Radiance = 5.19, Transcend = 5.64), but no change was noticed in Coke and artificial saliva (ΔE < 3.7). CONCLUSION: Ceramic brackets undergo color change when exposed to solutions of coffee, black tea and red wine. However, the same crystalline structure, either monocrystalline or polycrystalline, do not follow the same or a similar pattern in color change, varying according to the bracket fabrication, which shows a lack of standardization in the manufacturing process. Coffee dye produced the most marked color changes after 21 days of immersion for most ceramic brackets evaluated.