OBJECTIVE: This work aims to observe the healing of periimplant mucosal tissue injury in beagle dogs after subgingival retraction cord placement by examining the gingival index (GI), quantity of gingival crevicular fluid (GCF), and the proinflammatory cytokine in the GCF.
METHODS: In eight beagle dogs, the fourth mandibular premolars on the left side were extracted (n=8); after two months of healing, bone-level implants were installed. A plaque control regimen was performed throughout the duration of the experiment. After three months, retraction cords were placed subgingivally for 5 min before the cement-retained implant-supported crowns were cemented. GI, GCF quantity, and levels of tumor necrosis factor-alpha (TNF-α) in GCF were assessed before application and on days 1, 3, 7, 14, 28, and 56 after application.
RESULTS: GI, quantity of GCF, and TNF-α were significantly increased on days 1, 3, and 7 compared with those at the baseline and on days 14, 28, and 56 (P<0.05), and no statistically significant differences were observed among those on days 14, 28, and 56 and the baseline (P>0.05).
CONCLUSIONS: Under the circumstances of good oral hygiene, acute injury caused by placing retraction cord subgingivally in periimplant mucosal tissue of bone-level implant is reversible. GI, the quantity of GCF, and TNF-α on day 14 return to the baseline levels.
目的 通过观察比格犬种植义齿排龈后牙龈指数、龈沟液量和龈沟液中炎症细胞因子肿瘤坏死因子-α(TNF-
α)等指标的变化,探讨排龈所致种植义齿周围软组织损伤愈后情况。方法 拔除8只比格犬左侧下颌第四前磨牙(n=8),严格控制口腔菌斑,2个月后行骨水平种植体植入,3个月后行全冠粘接固位。全冠粘接前使用排龈线排龈5 min,排龈前和排龈后1、3、7、14、28、56 d,分别记录种植体的牙龈指数,测量龈沟液量并用酶联免疫吸附试验检测龈沟液中TNF-α的变化。结果 种植体牙龈指数、龈沟液量、TNF-α在排龈后第1、3、7天均大于排龈前和排龈后第14、28、56天(P<0.05),第14、28、56天恢复至排龈前水平,差异无统计学意义(P>0.05)。结论 保持良好口腔卫生的情况下,骨水平种植义齿周围软组织排龈线造成的排龈损伤是可逆性损伤,牙龈指数、龈沟液量、TNF-α在第14天恢复至排龈前水平。.