Stoilov Milan, Shafaghi Ramin, Stoilov Lea, Stark Helmut, Marder Michael, Enkling Norbert, Kraus Dominik
Department of Prosthodontics, Preclinical Education and Dental Materials Science, University Hospital Bonn, 53111 Bonn, Germany.
Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, 3012 Bern, Switzerland.
J Funct Biomater. 2025 Aug 16;16(8):296. doi: 10.3390/jfb16080296.
Primary implant stability is a critical factor for successful osseointegration and long-term implant success. This study investigates the impact of drilling protocol modifications on primary stability, considering different bone qualities and implant macro-designs, lengths, and diameters.
Three implant designs-two parallel-walled and one tapered-were tested with diameters ranging from 3.4 to 5.2 mm and lengths from 7.5 to 14.5 mm. Implants were placed in polyurethane foam blocks simulating different bone densities (10, 15, 25, and 35 PCF). A standard drilling protocol was used in all groups, with modifications based on bone quality: overpreparation in dense bone and underpreparation in softer bone. Primary stability was evaluated using insertion torque (IT). The optimal IT range was defined as 25-50 Ncm, based on clinical guidelines for immediate loading. The influence of drilling protocol adaptations on stability parameters was assessed.
Insertion torque was primarily influenced by bone density and implant diameter, with implant length playing a minor role. In dense bone (D1, D2), underpreparation improved torque values, especially in smaller implants, while overpreparation reduced them. The highest torques occurred with 5.2 mm implants, sometimes exceeding 80 Ncm. Standard protocols did not consistently achieve optimal torque across implant types. In soft bone (D3), underpreparation-particularly with tapered implants-was modestly beneficial. In very soft bone (D4), none of the protocols reliably reached the desired torque range.
Adapting drilling protocols to bone density improves insertion torque, especially with wider implants and in denser bone. Underpreparation is generally more effective than overpreparation. However, in very soft bone, neither implant geometry nor drilling adaptations reliably achieve optimal primary stability, highlighting the need for additional strategies.
种植体初期稳定性是骨结合成功及种植长期成功的关键因素。本研究考虑不同的骨质、种植体宏观设计、长度和直径，调查钻孔方案修改对初期稳定性的影响。
测试了三种种植体设计——两种平行壁式和一种锥形，直径范围为3.4至5.2毫米，长度为7.5至14.5毫米。将种植体植入模拟不同骨密度（10、15、25和35 PCF）的聚氨酯泡沫块中。所有组均采用标准钻孔方案，并根据骨质进行修改：致密骨过度预备，较软骨质欠预备。使用植入扭矩（IT）评估初期稳定性。根据即刻负重的临床指南，将最佳IT范围定义为25 - 50 Ncm。评估钻孔方案调整对稳定性参数的影响。
植入扭矩主要受骨密度和种植体直径影响，种植体长度起次要作用。在致密骨（D1、D2）中，欠预备可提高扭矩值，尤其是较小的种植体；而过度预备则会降低扭矩值。5.2毫米的种植体产生的扭矩最高，有时超过80 Ncm。标准方案并非始终能在所有种植体类型中实现最佳扭矩。在软骨质（D3）中，欠预备——尤其是对于锥形种植体——有一定益处。在极软骨质（D4）中，没有一种方案能可靠地达到所需扭矩范围。
使钻孔方案适应骨密度可提高植入扭矩，尤其是对于较宽的种植体和致密骨。一般来说，欠预备比过度预备更有效。然而，在极软骨质中，无论是种植体几何形状还是钻孔调整都无法可靠地实现最佳初期稳定性，这凸显了需要其他策略。
