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. 2018 Sep;88(5):596-601.
doi: 10.2319/120417-827.1. Epub 2018 Jun 18.

Scanning electron microscopy evaluation of aligner fit on teeth

Edoardo Mantovani, Enrico Castroflorio, Gabriele Rossini, Francesco Garino, Giovanni Cugliari, Andrea Deregibus, Tommaso Castroflorio

Scanning electron microscopy evaluation of aligner fit on teeth

Edoardo Mantovani et al. Angle Orthod. 2018 Sep.

Abstract

Objectives: The fitting of aligners on anchorage teeth is a crucial factor in clear aligner orthodontics. The purpose of this experimental study was to evaluate the fitting of two aligner systems, Invisalign and CA-Clear Aligner, using scanning electron microscopy (SEM).

Materials and methods: Passive aligners (Invisalign and CA-Clear Aligner) were adapted on resin casts obtained by stereolithography (STL) files of a patient, and then sectioned buccolingually. Upper and lower central incisors, upper and lower first premolars, and upper and lower first molars were the regions analyzed. Representative microphotographs of sections were taken with a scanning electron microscope (SEM); a total of 160 micrometric measurements were obtained and analyzed with ANOVA tests.

Results: Invisalign provided an overall better fit on lower incisors ( F = 11.48, P = .0095) and on lower molars ( F = 19.93, P = .0012). Considering the different regions, Invisalign provided better fit at the gingival edge of the buccal aspect on lower incisors ( F = 11.33, P = 0.0056) and at the gingival edge of the lingual aspect on upper premolars ( F =5.34, P = 0.0047). On the upper molars, Invisalign provided better fit at the gingival edge of the buccal aspect, while CA-Clear Aligner provided better fit at the buccal maximum convexity, on the buccal cusp, on the occlusal groove and at the palatal cusp. On lower molars, Invisalign showed a more accurate fit at the buccal aspect points.

Conclusions: Invisalign and CA-Clear Aligner exhibited comparable fit on anchorage teeth. Invisalign provided better fit at the gingival edges of aligners, while the CA-Clear Aligner provided better fit on complex occlusal surfaces.

Keywords: Aligners; CA-Clear Aligner; Fitting; Invisalign; Microscopy; SEM.

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Figures

Figure 1.
Figure 1.
SEM image: interaction between aligner and tooth; gingival edge of the aligner.
Figure 2.
Figure 2.
For anterior teeth, measurements were taken at six points: 1. Buccal gingival edge, 2. Half distance between border and maximum convexity, 3. Maximum convexity, 4. Incisal edge, 5. Cingulum, 6. Lingual gingival edge. For posterior teeth, measurements were taken at seven points: 1. Buccal gingival edge, 2. Maximum convexity of buccal surface, 3. Buccal cusp, 4. Central groove, 5. Palatal cusp, 6. Maximum convexity of lingual surface, 7. Lingual gingival edge.
Figure 3.
Figure 3.
Aligner fit on upper incisors.
Figure 4.
Figure 4.
Aligner fit on lower incisors.
Figure 5.
Figure 5.
Aligner fit on upper premolars.
Figure 6.
Figure 6.
Aligner fit on lower premolars.
Figure 7.
Figure 7.
Aligner fit on upper molars.
Figure 8.
Figure 8.
Aligner fit on lower molars.
See this image and copyright information in PMC

References

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