Introduction: A parallel design randomized clinical trial was conducted to compare dentoalveolar and skeletal changes in two groups of patients who had completed twin block therapy; one group had a three-month night-time retention period whereas the other group had no retention period, after twin block therapy but before fixed applianc- es. Methods: 26 participants of Malay ethnicity aged 10 to 15 years were included in the trial and had an overjet of 5mm or greater, molar relationship greater than half cusp Class II on a skeletal Class II base which had been corrected to a Class I molar relationship following twin block therapy. Following randomization, the 26 were divided into two groups of 13. Group A had fixed appliances bonded immediately whereas group B continued wearing twin block at night for three months, after which fixed appliances were bonded. Lateral cephalograms assessed were those taken before randomization, upon twin block therapy completion (T1) and six months after bond-up of fixed appliances (T2). Results: Paired t-test showed several statistically significant dentoalveolar and skeletal changes in group A. In contrast, only condylar head position exhibited a statistically significant change in group B. Despite a statistical sig- nificance, changes measured in both groups were minimal at less than 2mm and therefore clinically insignificant. Independent t-test showed no statistically significant difference between the changes recorded in both groups. Con- clusion: The results suggest that a three-month night-time retention period after twin block therapy does not lead to any changes that may be considered clinically beneficial.
Introduction: The aim of the study was to compare the changes in the skeletal and dentoalveolar structures in Malay patients with Class II Division 1 malocclusion treated by prefabricated re-mouldable customizable functional appli- ance (T4FTM) and Twin Block (TB) appliance. Methods: A randomised clinical trial was carried out with samples ran- domly assigned to active (TB appliance) and experimental (T4FTM appliance) groups. Pre- and post-treatment lateral cephalometric radiographs were taken for each subject and the overjet was clinically measured at the same intervals. 20 angular and linear measurements were chosen and measured separately. Results: Independent t test was used to compare the changes between the two groups. A significant difference between the groups was seen with overjet at 2.14 mm (p < 0.01), Sv_Pog distance at 1.83mm (p < 0.05), Sv_ii distance at 2.55 mm (p < 0.001), horizontal distance from the upper to the lower incisor tip at 1.81 mm which was statistically significant (p < 0.05). The other variables SNB and ANB angles too showed a significant difference. However, all the favourable changes were noted in the TB group. Conclusion: T4FTM appliance could be an effective appliance for the management of British Standard Institute's Class II Division 1 malocclusion on Class II skeletal pattern. However, the TB group differed significantly and had a more favourable correction in terms of the sagittal skeletal and dentoalveolar discrepancy.
Cephalometric analyses using computer software have more advantages than manual analyses. However, the software should be evaluated for the accuracy and reproducibility before it can be used. The aims of the present study were: 1) to compare the differences in accuracy and precision between utilizing scanned images and soft copy images with the software 2) to assess the reproducibility of software and manual cephalometric analyses. Fifteen cephalograms were selected randomly from the Record Unit, Hospital Universiti Sains Malaysia. All films had 10 fiducial points marked and were scanned at 75 dots per inch (dpi) and 300 dpi. Manual and digital measurements were compared to obtain magnification factors. Seven digital x-ray images of a caliper were taken. The mean differences were measured between the fixed caliper measurement and digital measurements. Subsequently, 37 cephalograms were traced manually and digitally with Computer-Assisted Simulation System for Orthognathic Surgery (CASSOS) software to assess its accuracy and reproducibility after applying the obtained magnification factor. Steiner analysis was utilized and T tests were used to evaluate the mean difference. P
Sex determination is one of the basic components in victim identification. This study aims to ascertain the sex of an individual from burnt teeth samples exposed at different temperature and time through nested polymerase chain reaction (PCR) on the amelogenin (AMEL) sex marker, to calculate the specificity and sensitivity, and to compare with previous relevant studies. A total of 17 teeth samples was subjected to burning at different temperatures ranging from 100°C to 500°C, at 2 to 10 minutes. The whole tooth was used for deoxyribonucleic acid (DNA) extraction by phenol-chloroform method. All samples were quantified for DNA concentration and then analyzed with nested PCR using two pairs of AMEL primer and results of sex typing were recorded. Out of 17 samples, genomic DNA extracted from 6 samples have concentrations ranging from 27.3 – 130.6 ng/μL. Nested PCR could amplify 16 samples for AMEL gene. Sex typing using AMEL gene showed 76.47% accuracy. Sensitivity of AMEL primer was increased from 6.67% to 63.64% using nested PCR technique; specificity of both external and internal primer was reported at 100%. Nested PCR of AMEL gene proved to be a suitable method for unequivocal determination of sex from degraded DNA samples.