Miniplast splints are usually referred to colloquially as tooth splints or bite splints.
They are manufactured on jaw models using pressure or vacuum forming processes and usually do not have any adjusted occlusal surfaces. The material blanks are made of transparent thermoplastic polyurethane (TPU), which is heated during manufacture and then shaped.
Miniplast splints differ in material type, thickness, strength and transparency and sometimes consist of several layers (multilayer technology). Because the used
TPU foils are thin (approx. 0,5 mm to 2,0 mm), they adapt optimally to the tooth-jaw structures when they are shaped, so that they are anchored very well on the dental arches. Due to their elasticity, they are also able to exert forces on teeth when there are differences between tooth position and splint configuration.
Thermoplastically formed miniplast splints can be used as simple bite aids as part of jaw joint therapy (so-called relief splints). They also serve as protection against attrition in bruxism (so-called crunching splints). Furthermore, they can be used as bleaching/medication carrier splints, as (passive) retention splints or as active orthodontic treatment devices for sequential tooth movements (splint positioner).
In order to use miniplast splints as an active orthodontic treatment, the position of the teeth must be changed step by step either manually on a setup model or virtually. Ultimately, this requires the production of a series of models on which the individual splints are made. The virtual procedure runs automatically in CAD/CAM technology according to the specifications of the practitioner using special software (e.g. the ClinCheck® from the manufacturer Align Technology, brand name Invisalign®) and process-controlled production.
Coming from America, the term "aligner" has established itself for this type of miniplast splints in Germany and throughout Europe; there are also names such as tray, splint and (rail) positioner. In addition, variants of protected brand names such as Harmonie, eCligner, Invisalign, Orthocaps splints, Nivellipso, Clear Aligner are used to name these devices.
A common feature of such splints is their low material thickness (and expansion), which justifies the term "mini". In contrast, classic bite splints have material thicknesses of several millimeters. The syllable "plast" denotes the elastic plastic material, which is a basic requirement for moving teeth with these splints.
Accordingly, the term "aligner" is to be regarded as an Anglicism of the term "miniplast splint" and is to be equated with the terminology (in terms of material and possible intended use).
For example, the market leader Align Technology with its product Invisalign® points out in its "Safety Data Sheet" that the material used is a "thermoplastic polyurethane/copolyester", i.e. the same family of materials from which numerous other mini-plastic splints are made getting produced.
In summary, it can therefore be stated from a technical and scientific point of view that a "miniplast splint" listed in material and laboratory cost lists corresponds conceptually to the Anglo-Saxon term "aligner" in terms of material, appearance and specific application.
