目的: 比较下颌磨牙区种植修复体不同穿龈形态对软组织的影响。方法: 纳入40例患者(44例单颗磨牙种植修复)，按黏膜厚度分为厚黏膜组(A组，黏膜厚度≥2 mm)和薄黏膜组(B组，黏膜厚度 < 2 mm)，随机纳入试验组和对照组。对照组采用复制愈合基台穿龈形态的修复体设计(A1、B1组)，试验组修复体的颊侧穿龈形态设计基于软组织宽度和高度比(width-to-height ratio, W/H)为1.3 ∶ 1的生物学比例进行设计(A2、B2组)，A2组的修复体穿龈形态设计为微凹形，B2组修复体的穿龈形态为微凸形。在修复体戴入前(T0)、戴入后1个月(T1)和戴入后12个月(T2)时进行评估。通过口内扫描获得软组织和修复体的信息，将不同时间点的口内扫描数据进行配准后，测量黏膜W/H、修复体穿龈角度(emergence angle，EA)和颊侧软组织边缘退缩(buccal mucosal margin recession，ΔGM)。结果: 戴牙后1年，试验组(A2和B2组)的ΔGM显著低于对照组(A1和B1组)。在厚黏膜组，A2组的ΔGM显著低于A1组(P=0.033)，薄黏膜组B1组和B2组的ΔGM差异无统计学意义。A2组的W/H在戴牙后1个月时显著增加，但在戴牙后1年保持稳定；A1组的W/H从初始到戴牙后1个月变化不大，但在戴牙后1年时，W/H显著增加。B2组的W/H从初始到戴牙后1年均保持稳定，B1组的W/H在戴牙后1个月变化不大，但在戴牙后1年时有显著增加。结论: 当黏膜厚度≥2 mm时，基于W/H生物学比例设计的微凹型的修复体穿龈形态，可以更好地维持颊侧黏膜水平；当黏膜厚度 < 2 mm时，修复体轮廓的调整对ΔGM的影响不大，但微凸形设计的修复体可以更好地维持种植体周围软组织的W/H。

Objective: To compare the influence of different emergence profile of implants in mandibular molar on the peri-implant soft tissue. Methods: Forty-four implants were divided into two equal groups by mucosal thickness, ≥2 mm (group A) or < 2 mm (group B), and were randomly included in the test group and the control group. In the control group, the patients were treated by a prosthesis with no transmucosal modifications (subgroups A1 and B1). In groups A1 and B1, the prostheses maintained the original emergence profile of the healing abutment. In the test group, the prostheses were designed based on a width-to-height ratio (W/H) of 1.3 ∶ 1 (subgroups A2 and B2). In group A2, the buccal transmucosal configuration design was slightly concave, and in group B2, the prostheses were designed with convex buccal transmucosal configuration. Assessments were made before delivery of the definitive restoration (T0), one month (T1) and 12 months (T2) after loading. The soft tissue and prosthesis information were obtained by intraoral scan and were converted to digital models. The digital models of different time were superimposed together. Buccal mucosal W/H, emergence angle (EA) and buccal mucosal margin recession (ΔGM) were measured. Results: One year after loading, the buccal mucosal margin recession in the test group (groups A2 and B2) was significantly lower than that in the control group (groups A1 and B1). The ΔGM in group A2 was significantly lower than that in group A1 (P=0.033), but in groups B1 and B2, it was not significantly different. The W/H in group A2 increased significantly one month after loading, but remained stable at one year. In the A1 group, the W/H changed little from initial to one month, but increased significantly at one year after loading. The W/H in group B2 remained stable from the beginning to one year, while in group B1, it changed little one month after loading, but increased significantly by one year. Conclusion: When the initial mucosal thickness was ≥2 mm, the slightly concave prosthesis designed based on the biological W/H significantly maintained the level of buccal mucosa. When the mucosal thickness was < 2 mm, the slightly convex prosthesis design maintained a more stable W/H over one year.