Nevins Myron, Chu Stephen J, Jang Wonwoo, Kim David M
Int J Periodontics Restorative Dent. 2019 Jan/Feb;39(1):29-37. doi: 10.11607/prd.3848.
A preclinical pilot study was performed to evaluate the safety, efficacy, primary stability, and wound healing of a hybrid dental implant with a unique macrogeometry design in which the coronal section is narrower and cylinder-shaped followed by a wider, tapered apical portion, each comprising approximately one half the length of the implant. Eighteen hybrid macrogeometry-designed dental implants were placed bilaterally into three foxhounds in the mandibular third and fourth premolar and first molar (P3, P4, and M1, respectively) extraction sockets of different dimensions immediately following full periosteal flap elevation and removal of teeth without socket grafting. Bone plate thickness, implant position and depth, gap distance, and insertion torque values were measured following implant installation. Surgical sites were healed uneventfully for 3 months, and then samples of soft and hard tissues surrounding the implants were retrieved to perform light microscopic and histomorphometric analyses. All 18 implants were stable and osseointegrated both clinically and radiographically. The analyses revealed that the amount of hard tissue alteration and bone fill that occurred during the healing period was significantly influenced by the thickness of the bone plate, the size of the horizontal buccal gap, and the implant diameter, position, and depth within the extraction socket. The P3 and P4 hybrid implants placed approximately 1.0 mm subcrestal from the interproximal height of bone with less gap distance (≤ 1.0 mm) exhibited minor to modest (1.5 to 2.0 mm) crestal bone remodeling relative to the implant platform. Conversely, M1 implants positioned with greater depth (≥ 2.0 mm) and gap distance (≥ 2.0 mm) that were evaluated in a buccal-lingual dimension exhibited minimal crestal change with first bone-to-implant contact within 1.0 mm (range: 0.00 to 0.89 mm) of the machined-collar surface. The thicker lingual bone plate on all M1 implants was relatively maintained and unaffected. The apical half of the implant provided high initial stability (range: 65 to 100 Ncm). The mean percentage of bone-to-implant contact was 56.34% (range: 40.15% to 72.04%). This preclinical study provided clinical and histologic evidence to support the safety and efficacy of a new hybrid macrogeometry implant design that achieved excellent primary and secondary stability in immediate extraction sockets without grafting.
进行了一项临床前试点研究，以评估一种具有独特宏观几何设计的混合式牙种植体的安全性、有效性、初始稳定性和伤口愈合情况。该种植体的冠部较窄且呈圆柱形，随后是较宽的锥形根尖部分，每部分约占种植体长度的一半。在完全掀起骨膜瓣并拔除牙齿（不进行牙槽窝植骨）后，立即将18颗具有宏观几何设计的混合式牙种植体双侧植入三只猎狐犬下颌第三和第四前磨牙以及第一磨牙（分别为P3、P4和M1）不同尺寸的拔牙窝中。在植入种植体后测量骨板厚度、种植体位置和深度、间隙距离以及插入扭矩值。手术部位顺利愈合3个月，然后获取种植体周围软组织和硬组织样本进行光学显微镜和组织形态计量学分析。所有18颗种植体在临床和影像学上均稳定且实现了骨整合。分析表明，愈合期内发生的硬组织改变和骨填充量受到骨板厚度、水平颊侧间隙大小以及种植体在拔牙窝内的直径、位置和深度的显著影响。相对于种植体平台，放置在距近中骨高度约1.0 mm牙槽嵴顶以下且间隙距离较小（≤1.0 mm）的P3和P4混合种植体表现出轻微至中度（1.5至2.0 mm）的牙槽嵴骨重塑。相反，在颊舌向维度上评估的深度较大（≥2.0 mm）且间隙距离较大（≥2.0 mm）的M1种植体表现出最小的牙槽嵴变化，在距加工颈表面1.0 mm（范围：0.00至0.89 mm）内首次出现骨与种植体接触。所有M1种植体较厚的舌侧骨板相对保持且未受影响。种植体根尖部分提供了较高的初始稳定性（范围：65至100 Ncm）。骨与种植体接触的平均百分比为56.34%（范围：40.15%至72.04%）。这项临床前研究提供了临床和组织学证据，以支持一种新型混合宏观几何种植体设计的安全性和有效性，该设计在即刻拔牙窝中无需植骨即可实现优异的初始和二次稳定性。
