Chang Chung-Chieh, Hong Alex, Mei Chih-Chun, Huang Yi-Fang, Liu Heng-Liang, Lin I-Ping, Hong Hsiang-Hsi
Department of Periodontics, Chang Gung Memorial Hospital Linkou Main Branch and Chang Gung University, Taoyuan City, 333, Taiwan.
New Taipei City Municipal Tucheng Hospital and Chang Gung University, New Taipei City and Taoyuan City, Taiwan.
J Dent Sci. 2023 Jan;18(1):264-271. doi: 10.1016/j.jds.2022.05.022. Epub 2022 Jun 11.
BACKGROUND/PURPOSE: Limited studies have discussed the convergent profiles regarding tapered implants based on biological considerations. This study analyzed the convergent angles (CAs) of premolar roots and imitated a tapered implant according to the anatomy of tooth roots.
A total of 60 single-rooted premolars were explored by micro-computed tomography. Every individual root was divided into 10 segments corono-apically, and the roots' buccolingual (BL) and mesiodistal (MD) CAs were measured by sections. To mimic a dental implant, the irregular shape of examined root cross-sections was transformed into a circular shape with equal areas. A biomimetic dental implant (BDI) was reconstructed and its CAs were compared with those of the natural roots' BL and MD at the examined levels and overall estimation.
In general, the maxillary and mandibular premolars demonstrated comparable CA patterns. However, significantly different CA patterns of BL, MD, and BDI were developed for both the maxillary and mandibular roots at the examined levels. The BL's CAs were greater than those CAs measured from the BDI and MD aspects, particularly for the sections at the middle and apical thirds of the roots. For overall CAs, the BDI's CAs were comparable with the average CAs of the BL and MD for both premolar groups.
Instead of a cylindrical configuration, the BDI prototype demonstrated a tapered model with a continuous slope. The average CA of BDI was 14°-24°, serving as a biological reference for future tapered implant design and research.
背景/目的：基于生物学考量，关于锥形种植体的融合轮廓的研究有限。本研究分析了前磨牙牙根的会聚角（CA），并根据牙根解剖结构模拟了一个锥形种植体。
通过显微计算机断层扫描对60颗单根前磨牙进行研究。每颗牙根从冠向根分为10个节段，通过切片测量牙根的颊舌向（BL）和近远中向（MD）会聚角。为模拟牙种植体，将所检查牙根横截面的不规则形状转换为面积相等的圆形。重建了一个仿生牙种植体（BDI），并将其会聚角与天然牙根在检查水平和总体评估时的颊舌向和近远中向会聚角进行比较。
总体而言，上颌和下颌前磨牙表现出可比的会聚角模式。然而，在检查水平上，上颌和下颌牙根的颊舌向、近远中向以及仿生牙种植体的会聚角模式存在显著差异。颊舌向的会聚角大于从仿生牙种植体和近远中向测量的会聚角，特别是在牙根中部和根尖三分之一处的切片。对于总体会聚角，仿生牙种植体的会聚角与两个前磨牙组颊舌向和近远中向的平均会聚角相当。
仿生牙种植体原型展示的不是圆柱形结构，而是具有连续坡度的锥形模型。仿生牙种植体的平均会聚角为14° - 24°，可为未来锥形种植体的设计和研究提供生物学参考。
