In vivo evaluation of tooth colour alterations during orthodontic retention: A split-mouth cohort study.

OBJECTIVES: To assess in vivo colour alterations of teeth following removal of fixed orthodontic appliances during retention. SETTING AND SAMPLE POPULATION: The Department of Orthodontics at the Aristotle University of Thessaloniki. Forty-eight patients after orthodontic treatment. MATERIAL AND METHODS: Debonding and cleaning procedures after orthodontic treatment were performed using two different carbide burs attached to a low or high-speed handpiece, respectively, in a non-blinded cohort study with split-mouth design. Spectrophotometric colour data of teeth were recorded: (a) after debonding, (b) three months later, prior to and following finishing with Soflex discs, and (c) after 1 year. The CIE Lab colour parameters were measured for each tooth, and the corresponding ΔΕ differences were calculated. The effect on colour was assessed with 3-way mixed ANOVA and Bonferroni's comparisons test (a < 0.05). RESULTS: Orthodontic debonding and cleaning procedures were found to have statistically significant effects on the CIE colour parameters of treated teeth, since the L* values decreased 0.6 units (P < 0.001), a* values were stable (0.0 units) and b* values increased 1.4 units (P < 0.001), during the first retention year. Finishing temporarily decreased the enamel colour differences. Total ΔΕ differences for all types of teeth measured ranged from 1.4 to 2.1 units. The greatest changes were exhibited during the first 3 months in teeth on which high-speed rotary instruments were used (1.6 units). CONCLUSION: The clinical relevance of this study points out that the colour of natural teeth following removal of fixed orthodontic appliances changes in long-term.

In vitro spectrophotometric evaluation of Vivera clear thermoplastic retainer discolouration.

AIMS: To investigate the in vitro effect of different staining solutions on the colour stability of Vivera retainers. METHODS: Thirty flat specimens fabricated using the Vivera material (Align Technology Inc., CA, USA) were assigned into five Groups (A, B, C, D and E) and immersed at 37 degrees C in solutions of distilled water (control), coffee, tea, red wine, and Coca-Cola. The CIE colour parameters (L*, a*, b*) of each specimen were measured before immersion (T0) and after 12 hours (T1), three days (T2) and seven days (T3) of solution exposure. Colour differences (AE) between the interval groups were calculated. Results: Significant differences were observed concerning (i) L* between T, and T0, Ti and T2 for Group B; (ii) a* between To and T,, T, and T3 for Groups B, C, D and E, as well as between T1 and T2 for Group C; and (iii) b* between To and T,, T2 and T3 for Group B and between T0 and T2 and T1 for Group C. The differences between δE(T1-T0), δE(T2-T0) and δE(T3-T0) were statistically significant for Groups B and C, as well as the difference between δE(T1-T0) and δE(T2-T0) for Group D. CONCLUSIONS: Coffee, tea and red wine caused visible changes in the retainers' colour.

Tooth-color assessment after orthodontic treatment: a prospective clinical trial.

INTRODUCTION: Our aim was to prospectively assess in-vivo color alterations of natural teeth associated with fixed orthodontic treatment. METHODS: Twenty-six consecutive patients were treated with fixed appliances bonded with a chemically cured or a light-cured resin with a split-mouth design. The spectrophotometric data of a standardized labial circular area of all teeth were recorded, before bracket bonding and after debonding and cleaning procedures. The color parameters of the Commission Internationale de l'Eclairage-L∗, a∗, and b∗ (lightness, red/green, and blue/yellow)-were measured for each adhesive and type of tooth, and the corresponding color differences (ΔE) between the interval groups were calculated. The effect of these parameters on color was assessed with 3-way mixed analysis of variance (ANOVA) and the Bonferroni comparisons test (α <0.05). RESULTS: Orthodontic treatment was associated with changes in color parameters. The L∗ values decreased (P <0.001), whereas the a∗ and b∗ values increased (P <0.001) at the end of treatment. All measured types of teeth demonstrated significant color changes (ΔE); their mean differences ranged from 2.12 to 3.61 ΔE units. Chemically cured resin was associated with greater color changes than light-cured composite. CONCLUSIONS: The color of natural teeth is changed in various ways after fixed orthodontic treatment.

Efficiency of noncompliance simultaneous first and second upper molar distalization: a three-dimensional tooth movement analysis.

Objective of this prospective study was the three-dimensional (3D) analysis of tooth movements after the noncompliance simultaneous distalization of the first and second maxillary molars. Ten patients (five girls and five boys; mean age: 13.2 years) with bilateral Class II molar relationships were treated with a noncompliance, fixed intraoral appliance. Upper second molars had already erupted in all cases. Dental casts and lateral cephalometric radiographs were taken immediately before placement and after removal of the appliance. The casts were 3D digitized and superimposed on a predefined area in the palate. The resulting holograms, as well as the cephalometric radiographs, were digitized and analyzed by means of customized cephalometric software. The whole procedure was repeated after a two- to four-week interval to estimate the error of both methods. The cast assessment of 3D sagittal and vertical tooth movements was more reliable than the cephalometric record. The average maxillary first molar distal movement was 2.8 mm. Anchorage loss was expressed by a 1.9-mm proclination of the central incisors. A substantial variation among patients and among the right and left side in the same patient was observed. Noncompliance simultaneous distalization of the first and second maxillary molars can be an efficient treatment option for the correction of Class II molar relationship. However, anchorage loss and individual variation have to be seriously considered. Bilaterally symmetrical effectiveness should not be relied upon.

Cephalometric changes following simultaneous first and second maxillary molar distalization using a non-compliance intraoral appliance.

AIM: The aim of this prospective study was to evaluate the dentoalveolar, skeletal and soft tissue changes induced by a modified minimal-compliance intraoral appliance following the simultaneous distalization of first and second maxillary molars. SUBJECTS AND METHODS: The study sample consisted of 14 patients with a mean age of 13.4 years treated by one clinician. In all cases a bilateral Class II molar relationship was corrected to Class I in a mean treatment period of 16.5 weeks. Lateral cephalometric analysis of the sample was based on the radiographs taken before and immediately after treatment with the appliance. The mean maxillary first molar distal movement was 1.4 mm, accompanied by a mean distal tipping of 6.8 degrees. The vertical change in molar position was insignificant. The anchorage unit was unable to completely resist the reciprocal mesial force of the activated coil spring. The second premolars were moved mesially by a mean 2.6 mm and tipped by a mean 4.1 degrees without significant extrusion. The mean increase in overjet was 0.9 mm, and the mean decrease in overbite 1.0 mm. RESULTS: The results of this study have shown that the presented intraoral appliance is an effective and reliable means of distalizing first and second maxillary molars simultaneously without the need for patient compliance. Appliance effects are limited primarily to the dentoalveolar structures. Mesial movement and slight protrusion of the anchorage unit have to be taken seriously into consideration during intraoral distalization.