ABSTRACTBackground: The improper irradiation process causes imperfect polymerization, so that the hardness of the composite resin, material strength, and color stability of the resulting composite resin are not optimal and water absorption increases. The long irradiation distance will result in the intensity of the light obtained getting smaller because the light can not reach the composite resin optimally and the degree of perfection of the polymerization of the composite resin will decrease. Objectives: The purpose of this study was to determine the difference between the irradiation distance and the degree of conversion of the bioactive composite resin and to analyze the ratio of the irradiation distance of 0 mm, 1 mm, and 5 mm to the value of the degree of conversion of the bioactive composite resin. Methods: This research uses a true experimental method with a post-test only design with a control group design with a simple random sampling technique. Results: The results showed that the highest degree of conversion of bioactive composite resins was at a 0 mm irradiation distance of 38.57%, 1 mm irradiation of 36.02% and the lowest was at a 5 mm irradiation distance of 31.90%. Conclusion: The highest degree of conversion of bioactive composite resin is at a 0 mm irradiation distance. Keywords: Beam distance, Composite resin, Degree of conversion, Light intensityABSTRAKLatar belakang: Proses penyinaran yang kurang tepat menyebabkan polimerisasi tidak sempurna, sehingga kekerasan dari resin komposit, kekuatan bahan, stabilitas warna dari resin komposit yang dihasilkan tidak maksimal serta penyerapan air meningkat. Jarak penyinaran yang jauh akan mengakibatkan intensitas sinar yang didapat semakin kecil karena sinar tidak dapat mencapai resin komposit secara optimal dan derajat kesempurnaan polimerisasi resin komposit akan berkurang. Tujuan: Tujuan penelitian adalah untuk mengetahui perbedaan jarak penyinaran terhadap nilai derajat konversi resin komposit bioaktif serta menganalisis perbandingan jarak penyinaran 0 mm, 1 mm, dan 5 mm terhadap nilai derajat konversi resin komposit bioaktif. Metode: penelitan ini menggunakan metode eksperimental murni (true experimental) dengan rancangan post-test only with control group design dengan teknik pengambilan sampel simple random sampling. Hasil: Hasil penelitian menunjukkan nilai derajat konversi resin komposit bioaktif tertinggi berada pada jarak penyinaran 0 mm sebesar 38.57%, penyinaran 1 mm sebesar 36.02% dan terendah berada pada jarak penyinaran 5 mm sebesar 31.90%. Kesimpulan: Nilai derajat konversi resin komposit bioaktif tertinggi berada pada jarak penyinaran 0 mm. Kata Kunci: Derajat konversi, Intensitas sinar, Jarak sinar, Resin komposit