اسم المؤلف:
اماني احسان الصقر
اسم المشرف:
اسماعيل حسين عزيز
اكرم فيصل الحويزي
المستخلص:
مصطلح الهايبودونشيا يعني نقص الاسنان الخلقي ويعد من اكثر التشوهات الفموية حدوثا لدى الانسان. مائة وخمسة وسبعون من مرضى نقص الاسنان الخلقي سجلوا في هذه الدراسة لديهم على الاقل سن واحد مفقود ولايزيد عدد الاسنان المفقودة عن ستة، قصدوعلاج الاسنان التقويمي في | Hypodontia means congenitally missing teeth, and considers as one of the most common oral alteration in human. One hundred and seventy five of hypodontia patients were matriculated in this study, having at least one missing tooth and no more than 6 missing teeth, seeking orthodontic treatment, who attended Al - Huwaizi Dental Center at AL - Harethia District - Baghdad, and control group consists of twenty five apparently healthy subjects (15 females, and 10 males). The age of both groups ranged from14 to 65 year. Buccal swabs were collected (for molecular study) from 25 of those patients who attended the clinic in a period between the beginnings of October 2013 to the end of April 2014, and from control group. Information were taken from the subjects under study according to a questionnaire that includes, name, gender, age, family and medical history, and the place of residence. Hypodontia was diagnosed according to the history of patients, clinical examination, orthopantomogram (OPG), and dental casts. The result of demographic study of hypodontia patients revealed that hypodontia was found in 129 of females which were more than that in males(46) with significant difference (p < 0.05). The ratio of females to males was 2.8 : 1. The missing teeth in hypodontia patients were found in right, left or both sides. The number of hypodontia patients, who had missing teeth in the right side were 37, in the left side were 48, while in both sides reached to 90 with non - significant differences and the results clarified that the missing teeth in anterior region found in 81 patients were higher than that in posterior region (63) while the least in both regions which recorded in 31 patient. It was found that hypodontia was more common in the maxilla (73) (upper jaw) than that in mandible (65) (lower jaw), whereas 37 suffering from missing teeth in both jaws, with non - significant differences. Present results showed that the maxillary lateral incisor (LI) was the most frequently missing tooth (124), the second most missing tooth was mandibular second premolar (PM2) (101) followed by lower central incisor (CI) (33), the maxillary second premolar(PM2) (27) whereas the lowest frequently missing teeth were canine (C), and the first premolar (PM1). The molecular part of present study used polymerease chain reaction (PCR) technique for amplification of DNA samples extracted from buccal swabs of twenty five hypodontia patients and control group.Four pairs of primers X1.1F, X1.3R; X1.4F, X1.4R; X2.1F, X2.3R, and X2.3F, X2.4R of the MSX1 gene, obtained from Bioneer Company (Korea), were used to amplify overlapping regions of the 2 exons of the MXS1 gene. The first pair of primers was used to amplify fragment with product size of 421 bp., while the second, third, and forth pairs of primers were used to amplify fragments with product size of 152 bp., 493 bp., and 264 bp., respectively. The outcome of MSX1 gene amplification showed that four patients with the first pair of primers and nineteen patient with the third pair of primers gave negative result (no bands) which differed from the result of the other patients and control. The disappearance of bands may be attributed to MSX1 microdeletion in those patients.The sequencing of MSX1 gene for the PCR product of second, third and fourth pairs of primer showed no genetic mutation, while the PCR product of the first pair of primers reveled nine missense and two silent mutations.It was concluded that hypodontia occurre frequently in Iraqi population and its occurrence in females was higher than that in males, and the gene MSX1 is responsible for many teeth missing in hypodontia patients.
