Mini dental implants (MDI) have proven to be a good alternative of the conventional implants to support lower overdentures in elderly edentulous patients with narrow residual ridge. The aim of the present study was to define drilling protocols for each diameter of the MDI in each bone quality. The number and the diameter of the drilling bur and the drilling depth was investigated. A total of 48 MDIs with a ball head and transgingival collar were used to the drilling protocol in four different bone qualities (Q1-Q4). All available four diameters of the implants were included: 1.8mm, 2.1mm, 2.4mm, and 2.9mm. The length of all implants was 15mm. Three different protocols were prepared for each of the four bone qualities and for each implant diameter. The insertion torques and the primary stability of the implants were measured in their final position. Regardless of implant diameter and bone quality, the insertion torque was significantly higher using drilling protocol 1 than 3 and using drilling protocol 2 than 3 as well. The insertion torque was significantly higher in bone quality Q1 than in Q2-Q4. The unscrewing resulted in considerably increase in the torque, which exceeded the insertion torques by up to two times. This repeatedly led to the bending and fractures of implants.

中文翻译：

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定义具有不同骨骼质量的微型牙科植入物的钻孔协议。

事实证明，微型牙植入物（MDI）是传统植入物的一种很好的替代方案，可以在残脊狭窄的老年无牙患者中支持较低的覆盖义齿。本研究的目的是为每种骨质MDI的每个直径定义钻孔方案。研究了钻针的数量和直径以及钻削深度。共有48个带有球头和龈下环的MDI用于四种不同骨质（Q1-Q4）的钻孔方案。包括了所有可用的四种直径的植入物：1.8mm，2.1mm，2.4mm和2.9mm。所有植入物的长度为15mm。针对四种骨质量和每种植入物直径准备了三种不同的方案。在其最终位置测量植入物的插入扭矩和基本稳定性。无论植入物的直径和骨质量如何，使用钻探方案1的插入扭矩都明显高于3，使用钻探方案2的插入扭矩也明显高于3。骨骼质量Q1的插入扭矩显着高于Q2-Q4。旋松会导致扭矩显着增加，超过插入扭矩的扭矩最多增加两倍。这反复导致植入物的弯曲和断裂。