Long-term studies have shown that various occlusal changes occur after the active phase of orthodontic treatment. some of these changes are unwanted changes and are considered as relapse The retention appliances are used to maintain the arch dimensions and alignment of the teeth after completion of the orthodontic treatment. One indicator of the functional state and health of the masticatory system is maximum voluntary bite force (MVBF). Its values vary in accordance to the location of measurement (highest at the first molar, lower at the incisors). People with pronounced horizontal craniofacial growth have somewhat higher values of MVBF, and those with vertical growth have lower values than do those with an average growth pattern. Clinical case reports and descriptive histologic data exist suggesting that bone and tooth remodeling persist for extended periods after removal of appliance or deactivation. A reflection of bone remodelling can be found in the gingival crevicular fluid (GCF) of moving teeth, with decrease or increase in the concentration of biomarker. This prompted us to evaluate the expression of variation in bone turnover marker levels (CTX-Bone resorption marker and BALP -Bone formation marker ) during the retention period. The International Osteoporosis Foundation (IOF) and International Federation of Clinical Chemistry (IFCC) have recommended C-terminal telopeptide of type I collagen (CTX) as one of the reference for BTMs. Hence, The present trial will be undertaken to assess the changes and compare if there is any difference in bite force and change in level of bone biomarker biomarker CTX type 1 collagen(C-terminal telopeptide of type I collagen and bone specific alkaline phosphatase(BALP) in post orthodontic treatment hypodivergent and hyperdivergent cases using beggs retainer over 12 months of period of retention.