Effects of various cleaning agents on polypropylene and copolyester thermoplastic orthodontic retainer materials

Hussein, Ayat; Mohammed-Salih, Harraa S.; Al-Sheakli, Iman I.

doi:10.1016/j.jtumed.2022.04.005

Cited by 5 publications

(6 citation statements)

References 23 publications

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“…These characteristics may be attributed to the lack of control in the manufacturing process. Some studies have shown [20,21] increased roughness and discoloration after hydration. However, during this study, these irregularities tended to be less accentuated after saliva immersions on the microscale.…”

Section: Discussionmentioning

confidence: 99%

“…In the oral environment, materials are subject to mechanical fatigue and hydrothermal degradation (ageing) [19]. The long-term use of a retainer induces discoloration and alteration of its optical properties, and the surface morphology shows distortions, microcracks, biofilm formation, and increased roughness [20,21]. Therefore, to maintain adequate strength during orthodontic treatment, an appliance must be replaced every 2 weeks [22].…”

Section: Introductionmentioning

confidence: 99%

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Surface Topography of Thermoplastic Appliance Materials Related to Sorption and Solubility in Artificial Saliva

Porojan,

Toma,

Gherban

et al. 2024

Biomimetics

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(1) Background: PETG (polyethylene terephthalate glycol) is a transparent, inexpensive, and versatile thermoplastic biomaterial, and it is increasingly being used for a variety of medical applications in dentistry, orthopedics, tissue engineering, and surgery. It is known to have remarkable properties such as tensile strength, high ductility, and resistance to chemical insults and heat, but it can be affected by various environmental conditions. The aim of the present study was to evaluate the topographical characteristics of four thermoplastic dental appliance materials in relation to water sorption in simulated oral environments (artificial saliva samples with different pH values). (2) Methods: The following four types of PETG clear thermoplastic materials were selected for the present study: Leone (L), Crystal (C), Erkodur (E), and Duran (D). In relation to the desiccation and water-uptake stages, their water sorption (Wsp) and solubility (Wsl) were calculated, and the surface topographies were analyzed on two length scales. The surface roughness was determined using a contact profilometer, and nanoroughness measurements were generated by three-dimensional profiles using an atomic force microscope (AFM). Statistical analyses (one-way ANOVA and unpaired and paired Student t-tests) were performed. (3) Results: After saliva immersion, the weights of all samples increased, and the highest sorption was recorded in a basic environment. Among the materials, the water uptake for the L samples was the highest, and for E, it was the lowest. In relation to water solubility, significant values were registered for both the L and C samples’ materials. After immersion and desiccation, a decreasing trend in microroughness was observed. The AFM high-resolution images reflected more irregular surfaces related to saliva immersion. (4) Conclusions: The sorption rates recorded in water-based artificial saliva were higher for basic pH levels, with significant differences between the samples. There were also significant differences related to the behaviors of the materials included in the study. In relation to roughness, on a microscale, the surfaces tended to be smoother after the saliva immersions, and on a nanoscale, they became more irregular.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Surface Topography of Thermoplastic Appliance Materials Related to Sorption and Solubility in Artificial Saliva

Porojan,

Toma,

Gherban

et al. 2024

Biomimetics

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“…To date, no studies have evaluated the effect of simulated gastric acid on vacuum-formed retainers. However, a few previous studies have assessed the effect of cleaning agents on exural strength of vacuum-formed retainers [37][38][39][40][41]. The results showed that there was either no change or an increase in the exural moduli of the thermoforming retainers after they were subjected to various cleaning agents.…”

Section: Flexural Strengthmentioning

confidence: 99%

Impact of Simulated Gastric Acid on the Physical and Mechanical Properties of Vacuum-Formed Retainers: An In Vitro Study

2024

Preprint

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Background A decrease in the oral pH levels may have detrimental effects on vacuum-formed retainers since an acidic oral environment could impact the mechanical and physical properties of these retainers. The present in vitro study aimed to evaluate the effect of simulated gastric acid at pH 4 and 1.2 on the surface microhardness, flexural strength, and color change of three different types of orthodontic retainer materials. Methods A total of 144 vacuum-formed commercially available retainer materials: copolyesters, polypropylene, and PET-G (n = 48/group) were evaluated. Each specimen was immersed in distilled water, and then the specimens were divided into two subgroups: those with a pH of 4 and those with a pH of 1.2. The microhardness test was performed using Innovatest, the flexural strength was evaluated by a universal testing machine, and the color change was analyzed using a spectrophotometer. The data were analyzed using One-Way ANOVA and paired t-tests at a significance value of P ≤ 0.05. Results Our findings indicated a significant decrease in flexural strength in all the experimental groups after immersion in pH 1.2 and 4 solutions (p-value = 0.000), with PET-G being the most affected material, followed by copolyester and polypropylene. Only two materials, copolyester, and PET-G, demonstrated a significant decrease in surface microhardness following immersion in a pH 4 solution (P = 0.001 and P = 0.025, respectively). The copolyester material exhibited the greatest degree of color alteration. Conclusion The study concluded that copolyester adversely affects flexural strength, surface microhardness, and color when subjected to immersion in simulated gastric acid. Therefore, care is recommended for patients diagnosed with gastroesophageal reflux disease.

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“…Because of the combination of excellent aesthetics, translucency, good mechanical strength, flexibility, and various applications in the dental field, clear thermoplastic materials have increased in popularity. Vacuum formed appliances are suitable for orthodontic retainers, temporomandibular joint and periodontal splints, mouth guards, and removable tooth aligners [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

“…Retainers are indicated for a long-term use in order to avoid orthodontic relapse [19]. Disadvantages associated with the long-term use of aesthetic retainers include decreased translucency and integrity of the material, discoloration, and increased roughness [3,20]. Stresses induced in thermoplastic materials by deformations tend to deteriorate the mechanical properties in time.…”

Section: Introductionmentioning

confidence: 99%

Topographical and Optical Characteristics of Thermoplastic Dental Appliances Materials Related to Water Sorption

Porojan

Toma

Bîrdeanu

et al. 2023

JFB

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Clear thermoplastic materials have increased in popularity in the dental field due to their various applications, combination of excellent aesthetics, and good biomechanical behavior, but they may be influenced by different environmental conditions. The purpose of the present study was to assess the topographical and optical characteristics of thermoplastic dental appliances materials relative to water sorption. PET-G polyester thermoplastic materials were evaluated in this study. Related to water uptake and desiccation stages, surface roughness was analyzed, and three-dimensional AFM profiles were generated for nano-roughness measurements. Optical CIE L*a*b* coordinates were recorded and parameters like translucency (TP), contrast ratio for the opacity (CR), and opalescence (OP) were derived. Levels of color changes were achieved. Statistical analyses were performed. Water uptake significantly increases the specific weight of the materials, and after desiccation, the mass decreases. Roughness increased after water immersion as well. Regression coefficients indicated a positive correlation between TP and a* and between OP and b*. Studied PET-G materials have a different behavior to water exposure, but for all their specific weight, they increased significantly within the first 12 h. It is accompanied by an increase in the roughness values, even if they continue to be kept below the critical mean surface roughness. On nano-level, 3D images show an increase in inhomogeneity in the network structure of particles. Slight color changes were registered.

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Effects of various cleaning agents on polypropylene and copolyester thermoplastic orthodontic retainer materials

Cited by 5 publications

References 23 publications

Surface Topography of Thermoplastic Appliance Materials Related to Sorption and Solubility in Artificial Saliva

Surface Topography of Thermoplastic Appliance Materials Related to Sorption and Solubility in Artificial Saliva

Impact of Simulated Gastric Acid on the Physical and Mechanical Properties of Vacuum-Formed Retainers: An In Vitro Study

Topographical and Optical Characteristics of Thermoplastic Dental Appliances Materials Related to Water Sorption

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