Biomedical subjects
Publications and source records attributed to Hayder Abdallah Hashim.
The aim of this paper is to present a new type of orthodontic removable retainer, which is of great help to the orthodontist as well as to the patient. The procedures of fabrication are described. The Reinforced Removable Retainer (Triple "R" Retainer) is well tolerated, adaptable, and easy to fit and remove. Its main advantage is that it is not easy to break, less bulky, and very retentive.
The purpose of this study was to establish tooth width and arch dimensions in normal and malocclusion samples and to compare tooth width and arch dimensions between males and females in normal and malocclusion samples. A total of 120 pairs of orthodontic study casts were included in the study. An electronic digital caliper was used for the measurements. Descriptive statistics and the t-test were used for the statistical analysis of the data. Tooth width and arch dimensions were established in normal and malocclusion in the present study. Significant differences were found in tooth width between normal and malocclusion samples. However, no significant difference was observed in arch dimensions. Furthermore, there was statistical significant difference in tooth width between males and females where the males showed higher mean values. The same was true when arch dimensions were compared. The results of the current investigation are of great value to the anthropologist as well as to the orthodontist in understanding dimensional arch criteria and orthodontic arch wire selection. Furthermore, it helps the prosthodontist in the selection of the correct shape and size of stock impression trays and of suitable molds of artificial teeth for fixed and removable prostheses.
The aim of this investigation was to study and compare the cephalometric soft tissue profile analysis between Saudis and Caucasian Americans. The study was carried out using standardized cephalometric radiographs of 56 Saudi subjects (30 males and 26 females) with pleasant and balanced facial profiles, competent lips, normal overjet and overbite, and showing no craniofacial deformities. Subject ages ranged from 22 to 23 years. One skeletal and thirteen soft tissue variables were investigated. F-test, two samples t-test, Mann-Whitney, and Wilcoxon tests were used for data analysis. The results showed no statistical significant differences between the Saudi males and females except for the angle of total facial convexity, soft tissue facial plane angle, lower lip length, sagittal nasal tip to the most protrusive lip distance, and also sagittal chin to the most protrusive lip distance. The Saudi females had a greater angle of total facial convexity and soft tissue facial plane angle than the males. In addition, the females had a shorter lower lip. They also had a short distance between the nasal tip and chin to the most protrusive lip. These results reveal significant differences in most of the soft tissue variables when comparing Saudis with Caucasian Americans as well as in other ethnic groups. Most of these variables are essential for the diagnosis and treatment planning of cases requiring orthodontics and orthognathic surgery.