Anchorage value of surgical titanium screws in orthodontic tooth movement

The aim of this study was to evaluate the clinical stability and anchorage value of titanium screws in orthodontic tooth movement. Nine patients, who needed maximum anchorage for canine retraction, were selected. Records of 10 patients with similar malocclusions who had received conventional treatment were used as controls. In the maxilla and mandible 27 mini-screws, diameter 2mm and length 9 or 11 mm, were used. At the end of the first stage of orthodontic treatment the first premolar teeth were extracted after taking a lateral cephalometric radiograph. After 1 week, a retraction force of 180 g was applied to the canines. The second cephalometric X-rays were taken and evaluated after the completion of canine retraction (mean duration of 23.2 weeks). Results were analysed using Fisher Exact, Wilcoxon signed ranks and paired t-tests. Displacement of the first molars and screws before and after treatment showed no significant changes in either the vertical or horizontal plane. The first molar movements in the study and control groups were only significant in the antero-posterior plane in both maxilla and mandible. Of the 9 screws in maxilla and 18 screws in mandible, 2 and 3 screws showed clinical failure, respectively. The failed screws were replaced by other screws that withstood the applied force until the end of treatment. In conclusion, titanium screws can be used reliably as a form of anchorage.

The use of index of orthodontic treatment need in an Iranian population

This study aims to evaluate the need for orthodontic treatment between 11 and 14 year old school children in Shiraz. A sample of 2000 students consisting of 1200 boys and 800 girls from various parts of the city was selected. The index of orthodontic treatment need (IOTN) was used by two calibrated examiners. The data was recorded in questionnaires to assess dental health components (DHC). Aesthetic components (AC) were evaluated both by students (AC) and examiners (ACE). The results for DHC of IOTN were: 18.39% of population showed severe and very severe need for treatment, 25.8% were in border line category, 48.1% had a slight need and the percentage for no need to treatment was 7.63%. In evaluating AC, 91.93% were in no need or little need, 3.91% in moderate need and 4.11% in great need to treatment group. Where as ACE resulted in: 91.31% no need and little need, 2.44% moderate need and 6.21% great need to treatment. There was a slight statistical correlation (0.54) between AC and ACE, but a very weak correlation between DHC and AC was observed. According to DHC, boys showed more need for treatment than girls (P=0.001). Grade 8 showed the most percentage in great need category in both AC and ACE (3.41% of 4.11% and 5.74% of 6.21%, respectively). The results indicate that the need for orthodontic treatment was less than other studies and most of the students were in the category of little need for treatment.