Case Studies
Twin Block Screw Advancement System
Introduction
The Twin Block Screw Advancement System enables orthodontists to quickly re-activate a twin block appliance in the clinic saving both patients and doctors time and reducing costs for the NHS.
The Problem
A Twin-Block appliance is a functional orthodontic appliance mainly used to treat Class 2 malocclusions where the lower jaw is under developed compared to the upper jaw. It can also be used for treating Class 3 relationships where the lower jaw is more prominent. It is by far the most popular functional appliance design in the UK.
Once the appliance is fitted, the patient is required to attend follow-up appointments. At these appointments it may be necessary to re-activate the appliance by adding to the working face of the upper blocks. Prior to the advent of the Screw Advancement System this was done by mixing and adding acrylic, either in the clinic or by sending the appliance to a dental laboratory.
To comply with health and safety requirements, the mixing and addition of acrylic to adjust the appliance should only be done in a laboratory environment. This requires an additional patient appointment for re-fitting and is time consuming for both the patient and the healthcare professional.
The Solution
The Twin Block Screw Advancement System was invented and developed by Gavin Carmichael, Principal Technologist and Laboratory Manager at East Lancashire Hospitals NHS Trust. This simplifies the adjustment of twin-block appliances by using screws fitted to a special housing incorporated in the appliance when it is constructed.
The appliance is reactivated by the addition of spacers of a known length between the screws and housings and thus avoids the need to mix or add more acrylic.
The Twin Block Screw Advancement System is licensed to, manufactured and sold by Ortho-Care (UK) Ltd.
The Process
Although the initial agreement between the Trust and company predated the establishment of TrusTECH, the Trust later sought advice from the TrusTECH. TrusTECH managed the extension of the licence terms on behalf of the Trust, to give the company permission to continue the manufacture and sale of the system.
Where can I get one?
For further information or to purchase the system click here.
Image 1. Pre-treatment (13.10.97); Overjet 12.5 mm; Twin block treatment started on 26.2.98
Image 2. Appliance in mouth after second advancement; 2 x 2 mm spacers added each side
Image 3. Post-treatment (14.6.99); Overjet 3.5 mm
Note. TrusTECH always recommends that NHS staff speak with it about an idea before they approach a third-party/company. This helps to ensure that the idea is adequately protected through legal (intellectual property) rights, preventing others from copying the idea and helps staff to negotiate the best deal possible for their Trusts.