J Dent Rehabil Appl Sci.  2020 Dec;36(4):222-231. 10.14368/jdras.2020.36.4.222.

Concept and application of implant connection systems: Part II. Placement and restoration of external connection implant and tissue level implant

• Ko KH
• Kang HG
• Huh YH
• Park CJ
• Cho LR

• KMID: 2512117
• DOI: http://doi.org/10.14368/jdras.2020.36.4.222

Abstract

To use the external connection implant (EXT) appropriately, the inter-implant distance should be carefully considered during placement, and the bones raised above the implants should be trimmed during the second surgery. The hex abutment is more useful than the non-hex abutment. EXT is particularly useful when the inter-arch space is limited. The tissue level (TL, internal butt connection) implant has a biomechanical advantage of coronal wall thickness and a biological advantage of an inherent transmucosal smooth surface. During TL implant restoration, an abutment can be selected using the abutment and fixture margins with considerations for the inter-arch space. Since no single type of implant can satisfy all the cases, it is necessary to select the appropriate type, considering the occlusal force and the bone condition.

Keyword

external connection; tissue level; abutment; placement

Figure

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  Fig. 1 (A) Comparison of external implant placed 25 years ago (#47i) and newly placed implant (#45i). The platforms are similar and can be connected with impression coping simultaneously. (B) Old external implant has wider horizontal platform, while this form cannot be observed in the newer one.

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  Fig. 2 Inter-implant bone loss induced by narrow interimplant distance. The inter-implant distance between EXT implants should be more than 3 mm.

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  Fig. 3 (A) Prosthesis cannot be placed due to overgrowing distal bone. (B) After bone profiling with instruments, the prosthesis can be placed completely. (C) Bone profiler.

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  Fig. 4 Misfit in the implant-abutment assembly. (A, B) CAD-CAM abutment misfit in regular diameter implant. (C) Internal space between implant-abutment assembly meant inappropriate titanium rod in wide diameter implant.

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  Fig. 5 Limited inter-occlusal distance. In this situation, external implant can be used rather than internal conical connection or tissue level implant.

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  Fig. 6 Comparison of vertical and horizontal moment depending on implant types. (A) EXT, (B) TL, (C) ICC. TL can provide most favorable vertical and horizontal moment.

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  Fig. 7 Implant shape and section. Wide neck in ICC (A) has thinner coronal wall thickness compared to flat neck ICC (C), while wide neck in TL (B) has thicker coronal wall thickness compared to flat neck TL (D).

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  Fig. 8 Various shape and diameter in TL implants. Ø4.0 (blue) implant for premolar implant placement with narrow horizontal bone condition. Ø4.5 (orange) implant for premolar implant placement with wide horizontal bone condition or molar implant placement with narrow horizontal bone condition. Ø5.0 (green) implant for molar implant placement with wide horizontal bone condition. Implant. Smooth surface height can be selected by considering the thickness of soft tissue. The number (Ø) shown above the implants indicates the coronal width of an implant.

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  Fig. 9 The types of abutment and connection. (A) Abutment margin system for sufficient inter-arch distance. Simple retrievability can be possible due to using upper bevel in TL. (B) Fixture margin system for limited inter-arch distance. Favorable crown shape can be possible. However, the removal of excess cement and perfect seating would be difficult in some cases.

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  Fig. 10 (A) 2 CAD-CAM abutments of TL implant made by different laboratory. (B) Scanning electron micrographic image of A abutment. Observation of the abutment below reveals the misfit of abutment. (C) Comparison of CAD-CAM abutments of TL made with different titanium blocks. The connection in the abutment is completely different.

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  Fig. 11 Selection of implant system considering occlusal load and biomechanical characteristics of implant. Left side meant single implant restoration, while right side meant multiple implant restoration.

Reference

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