Overview
This lecture reviews various dental retainer materials, their characteristics, and the features of new fixed lingual retainers.
Types of Retainers and Materials
- Lingual bars can be made from cobalt chromium or a titanium-vanadium-aluminum (Ti-V-Al) alloy.
- Optimised lingual bars use the same materials and are marketed under the Infinity brand.
- Single wire retainers may use medical-grade stainless steel (TMO Single Wire SSW).
- Combination retainers use cobalt chromium Ti-V-Al under brands like Infinity or Atlas.
- Clear vacuum-formed retainers (VFR) are made from polyurethane (brand: Hercules).
- Acrylic (PMMA) retainers are marketed as Hawley.
- Metal skeleton retainers use cobalt chromium (brand: Atlas).
- Retainer splints come in polyurethane, acrylic, or cobalt chromium (Atlas TMD, Infinity).
Features of Infinity Fixed Lingual Retainer
- Made from laser-sintered cobalt chromium or titanium alloy.
- The design features connected lingual platforms tailored to fit lower front teeth anatomically.
- Includes a unique positioning handle and seating jig for rapid and precise placement.
- The retainer is resin-bonded to the teeth.
- Its hygienic, slim profile allows for easy adaptation in the patient's mouth.
Biocompatibility of Materials
- Cobalt chromium and titanium are both highly biocompatible, with titanium offering extra corrosion resistance due to a stable oxide layer.
- Both metals are less likely to cause allergic or inflammatory responses, making them ideal for long-term dental devices.
- Titanium and cobalt chromium alloys are available in various colours for patient preference.
Key Terms & Definitions
- Lingual Bar — Retainer bonded to the back (lingual side) of front teeth.
- Cobalt Chromium (Co-Cr) — Metal alloy used for dental retainers due to strength and biocompatibility.
- Titanium Alloy (Ti-V-Al) — Titanium with vanadium and aluminum, offering durability and corrosion resistance.
- PMMA (Polymethylmethacrylate) — Acrylic resin used in removable retainers.
- Vacuum-Formed Retainer (VFR) — Clear retainer made from polyurethane that fits over teeth.
- Laser Sintering — Manufacturing process using lasers to fuse metal powder into a precise shape.
Action Items / Next Steps
- Review and compare the properties and uses of different retainer types and materials.
- Be prepared to discuss material biocompatibility and patient considerations for retainer selection.