AimTo determine the effects of implant timing and type of soft‐tissue grafting on histological and histomorphometric outcomes in a preclinical model.Materials and MethodsFour implant placement protocols were randomly applied at the mesial root sites of the third and fourth mandibular premolars in 10 mongrel dogs: immediate placement (group IP), early placement (group EP), delayed placement with/without alveolar ridge preservation (groups ARP and DP, respectively). A connective‐tissue graft (CTG) or porcine‐derived volume‐stable collagen matrix (VCMX) was applied to enhance the ridge profile (simultaneously with implant placement in group IP and staged for others), resulting in five sites for each combination. All dogs were sacrificed 3 months after soft‐tissue grafting. Histological and histomorphometric analyses were performed, and the data were analysed descriptively.ResultsCTG and VCMX were difficult to differentiate from the augmented area. The median total tissue thickness on the buccal aspect of the implant was largest in group IP/CTG (between 2.78 and 3.87 mm). The soft‐tissue thickness was generally favourable with CTG at all implant placement timings. Within the DP groups, CTG yielded statistically significantly larger total and soft‐tissue thickness than VCMX (p < .05). Among the groups with VCMX, group EP/VCMX showed the largest soft‐tissue thickness at apical levels to the implant shoulder.ConclusionsCTG generally led to greater tissue thickness than VCMX.

中文翻译：

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种植体植入时机和软组织移植类型对临床前犬模型组织学和组织形态学结果的影响

目的 在临床前模型中确定种植时机和软组织移植类型对组织学和组织形态学结果的影响。材料和方法在 10 只杂种狗的第三和第四下颌前磨牙的近中根部位随机应用四种种植体植入方案：立即放置（IP 组）、早期放置（EP 组）、延迟放置（分别为 ARP 组和 DP 组）（分别为 ARP 组和 DP 组）。应用结缔组织移植物 (CTG) 或猪源体积稳定胶原基质 (VCMX) 来增强牙槽嵴轮廓（与 IP 组中的种植体植入同时进行，并为其他组进行分期），每种组合产生五个位点。软组织移植后3个月处死所有狗。进行组织学和组织形态计量学分析，并对数据进行描述性分析。结果CTG和VCMX与增强区域难以区分。IP/CTG 组中种植体颊侧的中位总组织厚度最大（2.78 至 3.87 毫米）。在所有种植体植入时机下，CTG 的软组织厚度通常都是有利的。在 DP 组中，CTG 产生的总厚度和软组织厚度在统计上显着大于 VCMX（p< .05)。在使用 VCMX 的组中，EP/VCMX 组在种植体肩部的顶端水平处显示出最大的软组织厚度。结论 CTG 通常导致比 VCMX 更大的组织厚度。