서로 다른 디자인의 Microthread 임프란트의 시기별 안정도 변화
Stability change according to Healing time in the Four Differently Designed Microthread Implants
디자인 Microthread 임프란트 안정도;
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Crestal bone resorption around the implant, in many cases, caused gingival recession with resultant loss of gingival harmony and interdental papilla, which causes many esthetic problems. The purpose of this study was to compare the influence of pitch and thread design in four different microthread implants on the stability change. Microthread implants better prevent bone loss and have more stability. Three dogs were used. Their eight mandibular premolars were extracted 3 months before implantation. Implants have a difference in pitch(0.8-0.2, 0.6-0.3) and thread design(I-reverse buttress, S-buttress). Dog 1 received 4 different implants on both sides and sacrificed 3 days after implantation(3 days). In dog 2, 4 different implants were implanted in the left side, and after 2 weeks, additional 4 different implantation was performed on the right. Dog 2 was sacrificed 1 week after final implantation(1 and 3 weeks). For dog 3, 4 different implants were implanted in the right side, and additional 4 different implants on the left after 6 weeks. Dog 3 was sacrificed at 6 weeks from the last implantation(6 and 12 weeks). RFA and PTV of each implants were measured 3 times and 5 times on the day of implantation and sacrifice respectively. On the day of implantation, the stability of each implant was measured by Osstell(RFA) and Periotest(PTV), and compared by implants, pitches and thread designs. Then stability changes were compared by implants, pitches and thread designs according to healing time(3 days, 1 week, 3 weeks, 6 weeks and 12 weeks). Finally, the correlation between RFA(ISQ) and PTV was calculated. On the day of implantation, RFA of 0.8I and 0.6S, of pitch 0.8 and pitch 0.6, and thread design I and S showed significant differences. PTV showed no significant differences. All implants decreased in RFA at 1 and 3 weeks after implantation, however significant differences were observed in 0.8, 0.6, I, and S. All implants were clinically stable because ISQ values were more than 60 even in the lowest case of 3 weeks. Stability increased in almost all implants except for the case with excessive bone loss at 6 and 12 weeks. RFA changes were significant in I, 0.8, and 0.6. Significant correlation was present between RFA and PTV, but the number of data should be considered and the severe bone loss of 0.6S, implanted most distally, might influenced the result.