الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Achieving root parallelism is one of the mandatory treatment objectives to eliminate any addi¬tional trauma to the periodontium; by reduc¬ing the reopening of closed contact points between adjacent teeth leading to enhanced periodontal prognosis and increasing stability of the orthodontic treatment after extraction site closure.
The literature suggests that adult patients are more vulnerable to the incidence of external apical root resorption (EARR) where more orthodontic treatments are made and the apeces are already closed. Accordingly, adult patients require different treatment approaches from adolescents due to age related considerations including saging of tissues, vulnerability to root resorption, vulnerability to temporomandibular disorders and lack of growth potential.
The primary aim of this study is to assess the frequency of good root parallelism between maxillary canines and second premolars in adolescents versus adults group of patients requiring maxillary first premolar extraction during the orthodontic treatment. In addition to relate between the frequency of good parallelism and the type of malocclusion at the start of treatment. The secondary objective of this study is to indicate the incidence of root resorption after orthodontic treatment in both groups.
This study was an observational cross sectional analytical study, carried out at Orthodontic Department, Faculty of Dentistry, Cairo University. The sample of this study comprised post treatment panoramic radiographs (OPGs) of cases having extracted maxillary first premolar from the record archives of the outpatient’s clinic, Orthodontic Department, Cairo University. After fulfilling the eligibility criteria the sample was divided into two groups, Adult group of patients (mean age 23.7 years old ± 6.7), and adolescent group of patients (mean age 14.3 years old ± 3.9).