Reverse thrust double plate
Reversing double plates (abbreviation: RDP, also Sander III apparatus) are orthodontic devices ( braces ) for the treatment of mesial bite positions ( progeny ) in childhood, preferably beginning in the early mixed dentition before the age of nine.
They were developed by Franz Günter Sander in Ulm in the mid-1990s . Strictly speaking, reverse thrust double plates are active plates with special additional equipment, consisting of:
- a pair of spurs protruding downward from the upper plate at an anatomical angle
- a pair of adjustable abutments on the inside of the lower plate that come to rest in the mouth behind the spurs.
application
The technical problem is that the lower jaw can only be pushed back in small steps, unlike a feed (various double feed plates against the lower jaw rests are well known). With the RDP it is solved by the fact that the abutments for the spurs can be continuously screwed into the plate via screw threads. This gradually pushes the wearer's lower jaw back against the spurs. At the same time, the spurs transmit a reciprocal forward force to the top plate. The patients (parents) can also adjust the backward movement themselves according to the instructions of the orthodontist, whereby the time intervals must be adjusted so that the jaw bones and joints are not overwhelmed.
In order to give the RDP enough anchorage, fully grown first molars (6s) must be awaited. Because higher forces occur on the RDP than on uncoupled active plates, additional retaining brackets are advisable on additional teeth. If early treatment is to be started in the deciduous dentition, ready-made trainers (e.g. the splint activator ) offer the advantage of being independent of retaining teeth until then.
Proof of effectiveness
A significant skeletal effect on the maxilla, similar to that of extraoral forces, has been demonstrated. There was no increase in the vertical height of the face (opening of the bite), which would be counterproductive. The effect on the lower jaw was less pronounced and weaker. Thus, the RDP is recommended for those jaw anomalies of the progenous form that are more due to an underdeveloped upper jaw than to a particularly hereditary overdeveloped lower jaw. They often express themselves with a frontal or, in the case of a narrow jaw, also a lateral crossbite . In this case the RDP can be equipped with an expansion screw or a three-part Bertoni screw. A spring expansion screw is recommended in order to widen the upper jaw quickly and significantly. The RDP thus offers an alternative to the use of extraoral forces (e.g. Delaire mask, head and chin cap), which are not harmless for the temporomandibular joints, and at the same time to an accompanying or preparatory palatal expansion (fixed apparatus) using the oral muscle forces .
After normal interlocking has been achieved, the RDP can be carried on at night for retention (avoidance of relapse).
Individual evidence
- ↑ Franz-Günter Sander: Dental and skeletal effects when using the push-back double plate (SIII) for class III treatment. In: Information from Orthodontics & Orthodontics. 34, p. 345, doi : 10.1055 / s-2001-19680 .
literature
- Wolfgang Ott, Wolfgang Krug, HP Vollmer: Clinic and Practice Guide Dentistry, Georg Thieme Verlag 2002, 650 pages, ISBN 978-313-131781-0
- Franz-Günter Sander: Dental and skeletal effects when using the push-back double plate (SIII) for class III treatment
- Dental and skeletal effects during treatment of a Class III malocclusion with the Sander III (SIII appliance)
