Objective: To design a new index categorizing the functional need for orthognathic treatment. Design: Laboratory-based study. Setting: Records were obtained from two UK hospital-based orthodontic departments. Participants: A panel of four consultant orthodontists, experienced in providing orthognathic care, devised a new index of Orthognathic Functional Treatment Need (IOFTN) with the aid of the membership of the British Orthodontic Society Consultant Orthodontists Group (COG). Twenty-three consultants and post-CCST level specialists took part in the study as raters to test the validity and reliability of the new index. Methods: A total of 163 start study models of patients who had previously undergone orthognathic treatment were assessed by the panel of four consultant orthodontists using the new index (IOFTN) and the agreed category was set as the ‘gold standard’. Twenty-one consultants and post-CCST level specialists then scored the models on one occasion and two scored 50 sets of models twice to determine the test–re-test reliability. Results: Kappa scores for inter-rater agreement with the expert panel for the major categories (1–5) demonstrated good to very good agreement (kappa: 0·64–0·89) for all raters. The percentage agreement ranged from 68·1 to 92% in all cases. Intra-rater agreement for the major categories was moderate to good (kappa: 0·53–0·80). Conclusions: A new index, the IOFTN, has been developed to help in the prioritization of severe malocclusions not amenable to orthodontic treatment alone. It demonstrates good content validity and good inter-rater and moderate to good intra-rater reliability. As a result of being an evolution of the IOTN, the familiar format should make it easy to determine functional treatment need within daily orthognathic practice.

The objectives of this in vitro study were to produce a filled resin containing Ag-TiO2 filler particles and to test its antibacterial properties. Ag-TiO2 particles were manufactured using the ball milling method and incorporated into an epoxy resin using a high speed centrifugal mixer. Using UV/vis spectrophotometry investigations were performed to assess how the photocatalytic properties of the Ag-TiO2 particles are affected when encased in resin. Adopting the bacteria colony counting technique, the antibacterial properties of Ag-TiO2 particles and Ag-TiO2 containing resins were assessed using Streptococcus mutans under varying lighting conditions. Ag doping of TiO2 results in a band gap shift towards the visible spectrum enabling Ag-TiO2 to exhibit photocatalytic properties when exposed to visible light. Small quantities of Ag-TiO2 were able to produce a bactericidal effect when in contact with S. mutans under visible light conditions. When incorporated into the bulk of an epoxy resin, the photocatalytic properties of the Ag-TiO2 particles were significantly reduced. However, a potent bactericidal effect was still achieved against S. mutans. Ag-TiO2 filled resin shows promising antimicrobial properties, which could potentially be used clinically.

The aim of this study was to determine whether there was any difference in the degree of enamel loss at bond-up, debond and enamel clean-up when two different adhesive systems were tested and with four different methods of enamel clean-up. The adhesive systems were 37 per cent o-phosphoric acid with Transbond XT (group 1) and 10 per cent poly(acrylic acid) conditioner with Fuji Ortho LC (group 2). Using flattened enamel specimens, enamel loss at each stage was determined using a planer surfometer. These stages were: prior to treatment, at pumice prophylaxis, following enamel etching or conditioning and following enamel clean-up. The four clean-up methods were a high-speed tungsten carbide bur, a slow-speed tungsten carbide bur, an ultrasonic scaler and debanding pliers. The results, analysed using non-parametric tests, demonstrated that significantly more enamel loss occurred following the use of 37 per cent o-phosphoric acid than poly(acrylic acid) conditioner (P = 0.001). At debond and prior to clean-up, more adhesive remained on the enamel surface in group 1 than in group 2 (P = 0.005). During the subsequent enamel clean-up and with both adhesive systems, the least enamel loss occurred following the use of the slow-speed tungsten carbide bur and the greatest loss was seen with the ultrasonic scaler or high-speed tungsten carbide bur. Overall, the lowest enamel loss was observed with the poly(acrylic acid) conditioner and Fuji Ortho LC system (group 2) and where enamel clean-up was performed using the slow-speed tungsten carbide bur.