Aim: Medication-related osteonecrosis of the jaw (MRONJ)is a clinically significant complication associated withbisphosphonate therapy in patients with multiple myeloma.Preventive dental strategies are recommended to reduce thisrisk; however, the role of biochemical markers such as serumC-terminal telopeptide (CTX) in predicting MRONJ remainscontroversial. This study aimed to evaluate the impact ofpreventive dental management on MRONJ development inpatients with multiple myeloma receiving bisphosphonatetherapy and to assess the relationship between serum CTXlevels and MRONJ occurrence.Material and Method: This prospective study included 50patients with multiple myeloma who were followed betweenFebruary 2009 and April 2010. Twenty-five newly diagnosedpatients underwent serum CTX measurement and comprehensivedental examination prior to initiation of bisphosphonate therapy.When dental risk factors were identified, bisphosphonatetreatment was postponed until completion of necessary dentalinterventions. The study also included 25 previously diagnosedpatients who had already been receiving bisphosphonatetherapy without systematic preventive dental evaluation. SerumCTX levels were measured using the Elecsys β-CrossLaps assay,and their association with MRONJ development was analyzed.Results: No cases of MRONJ were observed in the newlydiagnosed group who underwent preventive dental evaluationprior to bisphosphonate initiation. In contrast, MRONJ occurredin 24% of patients in the previously treated group withoutpreventive dental management. Patients who developedMRONJ tended to have lower serum CTX levels comparedwith those who did not develop osteonecrosis; however, thisdifference was not statistically significant. Accordingly, CTXvalues did not demonstrate sufficient discriminatory capacityto serve as an independent predictive biomarker.Conclusion: Preventive dental examination and appropriatedental management prior to bisphosphonate therapy appear tobe effective strategies for reducing MRONJ risk in patients withmultiple myeloma. Although lower CTX levels were observedin patients who developed MRONJ, serum CTX alone does notprovide sufficient predictive value for MRONJ risk assessment.