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Browsing by Author "Al-Qawasmi, Riyad A."
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Item Analysis of a TNFRSF11A Gene Polymorphism and External Apical Root Resorption During Orthodontic Treatment(2005-07) French, Michael; Hartsfield, James K., Jr.; Al-Qawasmi, Riyad A.; Foroud, Tatiana M.; Roberts, W. Eugene; Shanks, JamesExternal Apical Root Resorption (EARR) can be an undesirable side effect of orthodontic treatment. Several studies have already recognized a genetic predisposition to EARR, and some have suggested possible candidate genes that may be involved. The objective of this prospective study was to explore one possible candidate gene that may predispose individuals to EARR during orthodontic treatment. The TNFRSF11A gene encodes the receptor activator of nuclear factor-kappa β (RANK). Together with the RANK ligand, RANK mediates cell signaling that leads to osteoclastogenesis. A diallelic marker was used to investigate the possible relationship between a nonsynonymous TNFRSF11A (RANK) polymorphism and the individuals' development of EARR concurrent with orthodontic treatment. Buccal swab cells of 112 patients who had completed orthodontic treatment were collected for DNA isolation and analysis. EARR of the maxillary central incisors was calculated based on measurements from pre and post treatment occlusal radiographs. Linear regression analysis indicated that length of treatment, overjet, and molar classification are significant predictors of EARR (p=0.05). Other factors, including age, gender, and overbite, were not found to be significantly associated with EARR. An ANOVA was performed to examine the relationship of the genotyped TNFRSF11A marker with the dependent variable EARR. When individuals having at least one copy of allele 2 (1,2 and 2,3 genotypes) were pooled together, a marginally significant association was found between EARR and the marker. Further analysis using logistic regression revealed that individuals with a (1,1) genotype are 4.3 times more likely to be affected by EARR than a person with a (1,2) or (2,2) genotype. From these findings it was concluded that EARR is a complex condition influenced by several treatment variables with the TNFRSF11A gene and its product (RANK) contributing to the individuals' predisposition.Item Evaluation of IL-1 B (+3954) Gene Polymorphism and External Apical Root Resporption Associated with Orthodontic Treatment(2005) Smith, Elizabeth Dockerty; Hartsfield, James K., Jr.; Al-Qawasmi, Riyad A.; Foroud, Tatiana M.; Roberts, W. Eugene; Shanks, JamesThe purpose of this prospective study was to examine the external apical root resorption (EARR) status and genetic marker composition of 100 Caucasian patients (59 females and 41 males) who have undergone orthodontic treatment at the private practice office of Dr. James V. Macri. A diallelic polymorphism marker for IL-1B +3954 within the candidate gene IL-1B was used to investigate the difference in relative risk for EARR. EARR measurements taken on pre and post treatment occlusal radiographs were then used to determine any association with genotype. Using linear regression analysis, length of treatment, overjet and molar classification were found to be significant predictors of EARR (p<0.05). The findings indicated that increased length of treatment or overjet is associated with increased EARR. Furthermore, those subjects with a class II molar classification were less likely to experience EARR compared to those with either a class I or class III molar classification. An ANOV A test was performed to examine the relationship of the IL-1B marker with the dependent variable EARR. There was no statistically significant association between the IL-1B genotype and EARR (p=0.53). Finally, a chi-square test was used to evaluate the association of the IL-1B genotypes in the affected (>5mm EARR) and unaffected (<5mm EARR) groups. There was no significant association between affection status and the IL-1B genotype (p=0.87).Item Genetic Factors in External Apical Root Resorption Associated with Orthodontic Treatment(2004-06) Al-Qawasmi, Riyad A.; Hartsfield, James K., Jr.; Everett, Eric T.; Roberts, W. Eugene; Foroud, Tatiana M.; Mah, JamesExternal apical root resorption (EARR) is a common sequela of orthodontic treatment, although it may also occur without orthodontic treatment. Despite rigorous investigation, no single factor or group of factors that directly causes root resorption has been identified. Experiment 1. A sample of 83 pairs of full siblings who had undergone orthodontic treatment was studied. Measurements were made of the longest maxillary central incisor, mandibular central incisor and mesial and distal roots of the mandibular first molars. Heritability estimates were generated by generalized liner models. Our results showed that the heritability estimate of the EARR was 64% on average. It was concluded that there was sufficient heritability for EARR to pursue genetic analysis. Experiment 2. Five polymorphic markers flanking or lying within the IL-IA , IL-JB, TNSALP, TNFA, and TNFRSFJ JA genes were used in a candidate gene approach to assess linkage and association with EARR in 38 pedigrees. Suggestive evidence for linkage between EARR and the polymorphic marker D18S64 was obtained with the analysis program MAPMAKER/SIBS (LOD score 2.51). The Q-TDT program showed highly significant (p = 0.0003) evidence of linkage disequilibrium of IL-1 B polymorphisms with EARR. Our analysis indicates that the JL -1 B polymorphism accounts for 15% of the total EARR variation. Experiment 3. Nine-week-old male mice were randomly selected as controls or for placement under anesthesia of an open coil spring ligated to the left maxillary first molar producing a force of approximately 25 g. The control (C) or treated (T) per strain were A/J (C=3,T=9), C57BL/6J (C=7,T=8), C3H/HeJ (C = 4,T=6), BALB/cJ (C=4,T=6), 129P3 /J (C=6,T=8), DBA/2J (C=8,T=9), SJL/J (C=8,T= 10), and AKR/J (C=9,T =8). Animals were sacrificed after nine days of treatment or control; maxillae were immediately removed, prepared, sectioned, mounted, stained with H&E, and observed microscopically at 1 OOX to determine root resorption. Mice were grouped into root resorption resistant (A/J, C57BL/6J and SJL/J); intermediate (C3H/HeJ and AKR/J); and susceptible (BALB/cJ, DBA/2J, and 129P3/J) strains. It was concluded that there were differential susceptibility or resistance to root resorption among inbred mouse strains, indicating that genotype is an influencing factor.