[Temulawak adalah tanaman obat unggulan Indonesia.Pertumbuhan S.mutans dan S. sanguinis yang berperan dalam pembentukanbiofilm pada permukaan email gigi, dapat dihambat oleh ekstrak temulawak. pHkritis biofilm ( 5.5) dapat mempengaruhi pelepasan ion kalsium email gigi.Xanthorrhizol dalam temulawak diketahui dapat mempertahankan pH netralmodel biofilm in vitro selama 4 jam. Tujuan: Menganalisis perubahan pH modelbiofilm Streptoccocus dual species dalam variasi waktu serta pengaruh paparanekstrak etanol temulawak terhadap kadar kalsium email permukaan gigi denganbiofilm Streptoccocus dual species. Metode: Model biofilm dibuat pada 6-wellplate yang telah dilapisi oleh saliva, kemudian ditambahkan S. Mutans dan S.sanguinis (1:1) dan diinkubasi dalam rentang waktu 1-24 jam, lalu pH diukurdengan menggunakan pH indikator. Selanjutnya model biofilm Streptoccocusdual species 16 dan 20 jam dibuat pada spesimen email gigi, kemudiandipaparkan ekstrak enatol temulawak (15%) selama 4 jam dan kadar kalsiumdiukur dengan alat Energy Dispersive X-ray (EDX). Uji beda dilakukan denganMann Whitney dan t-test (independent sample). Hasil: Model biofilmStreptoccocus dual species dapat mencapai pH kritis mulai jam ke 14 danbertahan sampai jam ke 24. Terdapat perbedaan rerata kadar kalsium (Wt%)antara kelompok kontrol dengan kelompok perlakuan, tetapi perbedaan tersebutsecara statistik tidak bermakna (p>0.005). Perbedaan rerata kadar kalsium (Wt%)antara kelompok perlakuan biofilm 16 jam (27,52 ± 0.89) dan 20 jam (24,92 ±0.85) secara statistik bermakna (p<0.005). Kesimpulan: Model biofilmStreptoccocus dual species dapat mencapai pH kritis setelah 14 jam. Paparanekstrak etanol temulawak tidak mempengaruhi secara signifikan kadar kalsiumpermukaan email gigi dengan biofilm Streptoccocus dual species. Namun,paparan ekstrak etanol temulawak pada kematangan biofilm berbeda,menghasilkan perbedaan kadar kalsium permukaan email gigi., Java turmeric is Indonesian medicinal plants. Growth of S. mutansand S. sanguinis that play a role in biofilm formation on the enamel surface, couldbe inhibited by java turmeric extract. Biofilms critical pH (≤ 5.5) could affect therelease of calcium ions enamel. Xanthorrhizol in java turmeric are known tomaintain a neutral pH in vitro biofilm models for 4 hours. Objective: To analyzethe changes in pH Streptoccocus dual species biofilm models in variationsexposure time as well as the influence of ethanol extract of java turmeric on toothsurfaces email calcium levels with Streptoccocus dual species biofilms. Methods:Biofilm model was made in 6-well plate that had been coated with saliva, thenadded S. Mutans and S. sanguinis (1:1) and incubated in a span of 1-24 hours, andpH was measured by using a pH indicator. Furthermore Streptoccocus dualspecies biofilm models 16 and 20 hours were made on specimens of enamel, thenpresented ethanol java turmeric extract (15%) for 4 h and calcium levels weremeasured by Energy Dispersive X-ray (EDX). Different test performed by MannWhitney and t-test (independent samples). Results: Streptoccocus dual speciesbiofilm model could reach critical pH ranging to 14 hours and last up to 24 hours.There are differences in the mean levels of calcium (Wt%) between the controlgroup and treatment group, but the difference was not statistically significant (p>0.005). Mean difference levels of calcium (Wt%) between treatment groupsbiofilms 16 hours (27.52 ± 0.89) and 20 hours (24.92 ± 0.85) was statisticallysignificant (p <0.005). Conclusion: Streptoccocus dual species biofilm modelcould reach a critical pH after 14 hours. Exposure to ethanol extract of javaturmeric did not affect significantly the level of calcium in the enamel surfaceStreptoccocus dual species biofilms. However, exposure of turmeric extract ondifferent maturity of biofilm, produced difference in the calcium level of enamelsurface.]