คุณสมบัติทางกายภาพของพอร์ตแลนด์ซีเมนต์ที่ปราศจากยิปซัมโดยผสมโพลีคาร์บอกซีเลตซุปเปอร์พลาสติไซเซอร์เพื่อใช้เป็นวัสดุปิดทับเนื้อเยื่อในโดยตรง / นรชัย วงศ์กรเชาวลิต = The physical properties of portland cement without gypsum mixed with polycarboxylate superplasticizer for using as a direct pulp capping material / Norachai Wongkornchaowalit
The purposes of this study were to investigate the effect of polycarboxylate superplasticizer on setting time and flow characteristic of white Portland cement without gypsum (AWPC), as well as, to compare the chemical compositions and physical properties of AWPC with ordinary white Portland cement (OWPC) and ProRoot MTA mixed with distilled water, in terms of net setting time, compressive strength, temperature and pH during setting, heavy metals contamination, particle size distribution and chemical compositions. The data were statistically analyzed at 0.05 level of confidence. The results showed that the setting time of AWPC were in the range of 7.03 ± 0.44 minutes which was significantly (p<0.001) lower than MTA and OWPC groups. The compressive strength of AWPC at 21 days and particle size distribution were not different from MTA. The pH value of AWPC (10.96) was significant lower than MTA (12.00) at 60 minutes (p<0.05). Temperature change during setting of all groups were less than 1 degree Celsius. The major chemical compositions and the amounts of heavy metal of AWPC were similar to MTA. The results indicate that AWPC is a potential material which can be developed as a direct pulp capping material.
