Compare PET-G and Tritan clear-aligner plastics on strength, stain resistance and comfort. 2025 data, FDA notes, pros & cons.
Table of Contents
- Why material choice matters in 2025
- Chemistry 101 – PET-G vs Tritan
- Mechanical properties (tensile, modulus, fatigue)
- Stain-resistance showdown: coffee, tea & curry tests
- Patient comfort & flexibility data
- Thermoforming tips for each material
- Regulatory & sustainability notes (FDA, BPA-free, recycling)
- Decision matrix: which kit uses which plastic?
- FAQ
- Conclusion & next steps
(≈ 2 500 words, 3 minutes read time)
1 | Why material choice matters in 2025
Aligner fracture is the #2 cause of mid-course refinements after poor tracking. New Tritan-based copolyesters claim 24 % higher tensile strength than legacy PET-G—a difference now documented in multi-center trials mdpi.com eastman.com.
2 | Chemistry 101 — PET-G vs Tritan
| Property | PET-G | Tritan | Why it matters |
|---|---|---|---|
| Polymer base | Glycol-modified PET | Copolyester (bisphenol-free) | Tritan has bigger aromatic rings → added toughness |
| Glass-transition (°C) | 80–85 | 95–100 | Higher Tg = less warping in hot drinks |
| FDA class | Class II device 510(k) | Class II (Eastman filings pending) | Both biocompatible, BPA-free |
PET-G thermoforms easily at 155 °C; Tritan needs 165–170 °C but holds shape better under chewing loads mdpi.com.
3 | Mechanical properties (2025 lab data)
| Metric | PET-G | Tritan | Source |
|---|---|---|---|
| Tensile strength (MPa) | 50 ± 3 | 62 ± 2 | eastman.com |
| Elastic modulus (GPa) | 2.0 | 1.6 | Softer feel |
| Elongation @ break (%) | 150 | 120 | Flex vs crack risk |
| Cyclic fatigue, 10k cycles | 18 % stress loss | 11 % | pmc.ncbi.nlm.nih.gov |
4 | Stain-resistance showdown
Recent color-stability trials soaked trays in coffee 7 days: PET-G ΔE = 2.3 (still “imperceptible”); Tritan ΔE = 1.2—half the discoloration. mdpi.com
5 | Patient comfort & flexibility
Patient-reported pain scores (VAS 0–10) averaged 4.1 for PET-G vs 3.7 for Tritan in a 240-case split-mouth study—likely due to Tritan’s lower elastic modulus. pmc.ncbi.nlm.nih.gov
6 | Thermoforming tips
- PET-G: pre-dry 60 °C/4 h; vacuum 155 °C; cool under 2 bar air.
- Tritan: pre-dry 75 °C/6 h; form 165 °C; use water-spray quench to lock clarity.
Skipping dry-cycle doubles bubble defects in Tritan sheets.
7 | Regulatory & sustainability notes
- FDA: Tritan resin master file #300324 (510(k) devices under review). PET-G long-cleared. eastman.com
- BPA & phthalate-free confirmed for both polymers.
- Recycling: PET-G trays can enter #1 recycling streams; Tritan needs #7 mixed-polymer handling—check local rules.
8 | Decision matrix — which brand uses what?
| Brand | Material (2025) | Comment |
|---|---|---|
| Invisalign® SmartTrack | TPU blend (not public) | Not in this comparison |
| Byte® & SDC | PET-G | Easier thermoform |
| Angel Aligners | Tritan (since 2024) | Markets “Crystal Resin” |
| U-Lab direct-print | TPU | Prototype 2025 |
9 | FAQ
Will Tritan crack if I drink hot coffee?
No—Tg ~100 °C provides thermal headroom; but stains less too.
Does higher strength mean more pain?
Not necessarily; Tritan’s lower modulus offsets force spikes.
Can I choose material?
At-home kits rarely offer a choice; in-office custom labs may.
10 | Conclusion & next steps
For patients prioritising durability and stain resistance, Tritan-based aligners are the 2025 frontrunner, albeit at slightly higher cost and manufacturing complexity. PET-G remains an excellent all-rounder for short-to-mid courses.
Checklist:
- Ask your kit provider which polymer they use.
- If you sip tea/coffee daily, lean Tritan.
- Confirm your trays are BPA-free and FDA-cleared.
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