Barbizam Joao V B, Massarwa Rasha, da Silva Lea Assed Bezerra, da Silva Raquel Assed Bezerra, Nelson-Filho Paulo, Consolaro Alberto, Cohenca Nestor
Department of Endodontics, School of Dentistry, University of Washington, Seattle, WA, USA.
Dent Traumatol. 2015 Feb;31(1):29-34. doi: 10.1111/edt.12131. Epub 2014 Oct 14.
The extra-alveolar dry period and storage medium in which the tooth was kept prior to replantation remain the critical factors affecting the survival and regeneration of the damaged periodontium. When the replantation is delayed, replacement root resorption is the most common complication following replantation of an avulsed tooth. The aim of this histological study was to evaluate the periodontal healing of replanted dogs' teeth after 20 min (short) and 60 min (long) extraoral dry time with and without the application of enamel matrix proteins. Eighty mature premolar roots (40 teeth) maxillary and mandibular premolars were extracted, the root canals were accessed, instrumented, and filled using a lateral condensation technique, and the access cavity was restored with amalgam. Each root was randomly assigned to one of experimental groups: Groups I and II: Roots were replanted after an extraoral dry time of 20 min. In group II, Emdogain(®) (Biora, Malmo, Sweden) was applied directly to the external root surface with complete coverage. Groups III and IV: Roots were replanted after an extraoral dry time of 60 min. In group IV, Emdogain(®) was applied to the whole external root surface before replantation. Roots that replanted within a total extraoral dry time of 10 min were used as negative controls, while those replanted after 90 min of extraoral dry time were assigned as positive controls. After 4 months, the dogs were euthanized, and the maxillary and mandibular processes were processed for histology and microscopically evaluated. Statistical analysis showed no significant differences (P = 0.1075) among the experimental groups. The results of this study show that 20 min of extraoral dry time is as detrimental to the PDL cells as 60 or 90 min of extraoral dry time, with avulsed dogs' teeth, even when replanted with an inductive material such as EMD. This study provides strong evidence in relation to the threshold of the extraoral dry time of avulsed teeth, suggesting that the extraoral dry time threshold of PDL cell viability is significantly less than that which current guidelines promote.
牙槽外干燥期以及牙齿再植前保存牙齿的储存介质仍然是影响受损牙周组织存活和再生的关键因素。当再植延迟时，替代性牙根吸收是牙齿脱落后再植最常见的并发症。本组织学研究的目的是评估在有或没有应用釉基质蛋白的情况下，经过20分钟（短）和60分钟（长）的口外干燥时间后，再植犬牙的牙周愈合情况。拔除80颗成熟的前磨牙牙根（40颗牙齿），即上颌和下颌前磨牙，开髓，使用侧方加压技术进行根管预备和充填，并用汞合金修复髓腔。将每颗牙根随机分配到其中一个实验组：第一组和第二组：口外干燥20分钟后再植。在第二组中，将Emdogain（®）（Biora，瑞典马尔默）直接完全覆盖在牙根外表面。第三组和第四组：口外干燥60分钟后再植。在第四组中，再植前将Emdogain（®）应用于整个牙根外表面。在口外总干燥时间10分钟内再植的牙根用作阴性对照，而口外干燥90分钟后再植的牙根用作阳性对照。4个月后，对犬实施安乐死，对上颌和下颌进行组织学处理并进行显微镜评估。统计分析显示实验组之间无显著差异（P = 0.1075）。本研究结果表明，对于脱落后的犬牙，20分钟的口外干燥时间与60分钟或90分钟的口外干燥时间一样，对牙周膜细胞有害，即使使用诱导材料如EMD进行再植也是如此。本研究为脱落后牙齿的口外干燥时间阈值提供了有力证据，表明牙周膜细胞活力的口外干燥时间阈值明显低于当前指南所提倡的时间。
