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. 2023 Jan;18(1):264-271.
doi: 10.1016/j.jds.2022.05.022. Epub 2022 Jun 11.

Convergent angles of a tapered implant referred from the root profile of premolars

Chung-Chieh Chang  1 , Alex Hong  1 , Chih-Chun Mei  2 , Yi-Fang Huang  3 , Heng-Liang Liu  4 , I-Ping Lin  5 , Hsiang-Hsi Hong  1
Affiliations

Convergent angles of a tapered implant referred from the root profile of premolars

Chung-Chieh Chang et al. J Dent Sci. 2023 Jan.

Abstract

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.

Materials and methods: 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.

Results: 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.

Conclusion: 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.

Keywords: Anatomy; Biomimetics; Dental implants; Tooth root; X-ray microtomography.

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Conflict of interest statement

The authors have no conflicts of interest relevant to this article.

Figures

Figure 1
Figure 1
Three-dimensional reconstructions from microcomputed tomography images. a–c: Maxillary premolars; d–f: Mandibular premolars. a & d: Convergent angles (CAs) from the buccolingual measurement. b & e: Transformation of the natural root into a biomimetic dental implant (BDI). rn: radius of the cross-section at the examined level. rn+1: radius at the next level apical to rn. H: length of each adjacent slice. θ: angle formed by the long axis and one side of the BDI. c & f: CAs from the mesiodistal measurement.
Figure 2
Figure 2
Comparison of the overall convergent angles between the buccolingual (BL) and mesiodistal (MD) direction and the biomimetic dental implant (BDI). a: Maxillary premolars. b: Mandibular premolars.
See this image and copyright information in PMC

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