Latar Belakang: Pengisian dengan kon gutaperca berlapis resin (GBR) dan siler resin metakrilat menciptakansuatu sistem monoblok tersier. Tujuan: menganalisis perbandingan kerapatan antara pengisian GBR dan gutaperca konvensional (GK) dengan siler resin metakrilat di daerah sepertiga apeks.Metode:Tiga puluh dua gigi insisif bawah, dibagi dua kelompok sama besar, yaitu kelompok GBR dan GK dengan masing-masing kelompok menggunakan siler resin metakrilat. Setelah pengisian saluran akar dengan tekniksingle-cone, sampel diinkubasi (370C, 24 jam), kemudian dibelah dua secara vertikal. Dilakukan pemeriksaan kerapatan sepertiga apeks berdasarkan celah mikro yang ada pada daerah 5mm dari apeks menggunakan SEM dan diberi skor. Analisis data menggunakan uji Kolmogorov-Smirnov. Hasil: Skor 0 terbanyak pada GBR 43.8%,skor 1 terbanyak pada GK 81,3%% (165), skor 2 0% dan skor 3 terbanyak pada GBR 12.5%.Kesimpulan: Kerapatan hasil pengisian dengan kon gutaperca berlapis dibanding gutaperca konvensional dengan masing-masing kelompok menggunakan siler resin metakrilat pada sepertiga apeks tidak ada perbedaan bermakna walaupun secara subtansi jumlah celah mikro pada kelompok gutaperca berlapis lebih sedikit didaerah sepertiga apeks

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Background:Resin-coatedguttapercha as aroot canal obturation material is the system of tertiary monoblock. Purpose: to compare sealability of obturation using methacrylate resin-based root canal sealer between GBR dan GK group. Methods: Thirty two human lower insisive was used as specimen.All specimen was prepared using REVO-S and divided randomly into two groups. First group, GBK was obturated with resin-coated guttapercha andmethacrylate resin-based root canal sealer; while GK group was obturated with conventional guttapercha with the same sealer.Afterobturation, the specimens were incubated (370C, 24 h), then the speciments was cut verticaly. The gap existance was measured using SEM and given score 0-3. Theresults were statistically analyzed with Kolmogorov Smirnov test. Results:Thelargest proportion distribution in GBR group was score 0 (43.8%), whilst the largestproportion distribution in GK group was score 1 (81.3%), both these groups has no score 2, and the largest proportion distribution in GBR was score 3(12.5%) Conclusion: Resin-coated guttapercha as an obturation material hadinsignificancy diffrence statisticaly than conventional guttapercha of sealing ability, despite resin-coated guttapercha showed better sealing ability substantially.