Surface Evaluation of Aligners after Immersion in Coca-Cola and Orange Juice

Abstract

Orthodontic removable appliances made of transparent thermoplastic materials—aligners—are becoming increasingly popular in contemporary orthodontic practice. It is important for the clinician to fully understand the mechanical properties and behavior of the appliance used. Because of that, the aim of our study was to investigate the changes in aligner surface after immersion in Coca-Cola and orange juice. For surface evaluation, fractal analysis, texture analysis, and wetting angle measurement were performed. Statistically significant changes were found between some of the groups in the fractal dimension analysis. In texture analysis, all but one intergroup comparison showed statistically significant differences. For wetting angle assessment, statistically significant differences were found. These were, however, more numerous when assessing glycol droplets, rather than water droplets. Fractal dimension analysis confirmed a correlation between the intensity of changes in the aligner surface with immersion time in the liquids assessed. Texture analysis showed a high sensitivity to the changes in aligner surface. It failed, however, to reveal changes relative to immersion time. Wetting angle analysis revealed aligner surface degradation for Coca-Cola. It did not, however, prove the dependence of the intensity of this degradation as a function of time. Both Coca-Cola and orange juice can cause aligner surface degradation.

Clinically Relevant Properties of 3D Printable Materials for Intraoral Use in Orthodontics: A Critical Review of the Literature

“…It should indeed be considered that the aging method adopted by Pratsinis et al [ 54 ] and Willi et al [ 55 ], only involving aqueous immersion of the aligner, underestimated the effect on resin degradation and leaching of the factors acting intraorally, such as pH, temperature, bacterial and enzymatic activity, occlusal and masticatory forces [ 56 , 57 ].…”

“…It should, however, be mentioned that all the biocompatibility tests were based on substances released from the specimens by passive hydrolysis and failed to assess the effects of intraoral influential factors, such as salivary enzymes, functional and parafunctional loads, temperature variations, pH changes such as those related to the consumption of soft drinks or juices [ 57 ], microbial activity. Such experiments omit to evaluate the challenge of the oral environment on polymers degradation and are only useful to compare 3D-printed appliances with other commercially available or conventionally manufactured devices.…”

Comparison of Two Chosen 3D Printing Resins Designed for Orthodontic Use: An In Vitro Study

“…One of these external factors is food and beverages. Warnecki et al [ 22 ] confirmed that acidic drinks, such as coca cola and orange juice, can damage the structure of the clear aligners’ splints. Damage to the structure would impair tooth movement.…”

“…It is also known that the properties of these materials deteriorate over time, not only because of external conditions, but also due to material wear. This phenomenon also occurs in 3D-printable dental materials [ 22 , 34 ]. Although this was not the subject of the present investigation, future investigations should consider these aspects as an interesting path in this developing branch of dentistry.…”

The Influence of Polishing and Artificial Aging on BioMed Amber® Resin’s Mechanical Properties

“…This could influence the material's surface. Moreover, the use of beverages and food as well as bleaching, damages the surface of the materials applied in dentistry [22,23]. The color change is also observed when cigarette smoke is an influencing factor [24].…”