Comparative assessment of clinical performance of esthetic bracket materials

Abstract

Objectives: To compare the alterations in esthetic appearance and slot morphology/integrity of two main types of esthetic brackets caused after clinical use.

Materials and methods: Sixteen ceramic (CR) and 16 plastic (PR) central incisor brackets were obtained from 16 young adult patients at the end of treatment in a prospective randomized manner. As controls, 12 ceramic (CC) and 12 plastic (PC) nonused brackets were also examined. Three representative slot width measurements were obtained through micrometric microscopy. Visual inspection of optical microscopy images, surface electron microscopy (SEM), and energy-dispersive x-ray spectroscopy (EDS) were also performed.

Results: Intraoral exposure time varied from 5 to 20 months (mean, 12.4; P = .73). Two-way analysis of variance revealed significant differences in slot width among the different materials and a significant interaction between the material effect and its status (P < .001). Bonferroni post hoc tests on material × status effect showed significant differences between CC (95% confidence interval [CI]: 434.5, 447.0) vs PC (95% CI: 460.2, 472.8), CC vs CR (95% CI: 453.2, 464.4), and PC vs PR (95% CI: 448.8, 458.9). Interestingly, a significant difference was not detected for CR vs PR. Slot width was correlated with the time under clinical use only for plastic brackets (PR: r = -.64, P < .01). Visual inspection of the optical microscopy images did not reveal any major macroscopic morphological disfigurements or significant discolorations. However, a rough and irregular slot wall surface was evident after clinical use (also with SEM), especially in the bottom of the slot.

Conclusions: Both bracket types presented adequate clinical performance at least for the time period studied and in terms of esthetic appearance and morphologic integrity.

Figure 1

Optical microscopy images of ceramic retrieved (CR, left) and plastic retrieved (PR, right) brackets after 17 months of clinical use. Note the discoloration (shown as black) at the bottom of the slot in both brackets and at the gingival side of the wing slot to base connection in the PR bracket.

Figure 2

Secondary electron images (SEi), obtained through surface electron microscopy, of ceramic control (CC, upper left), plastic control (PC, upper right), ceramic retrieved (CR, lower left), and plastic retrieved (PR, lower right) brackets. The CR and PR brackets shown were retrieved after 7 months of clinical use.

Figure 3

Energy-dispersive x-ray spectroscopy spectrums for element identification in ceramic control (CC) and plastic control (PC) brackets.