ReviewCureus2026
Marginal Bone Loss and Peri-Implant Clinical Outcomes of Internal Hexagonal and Internal Conical Implant Abutment Connections: A Narrative Review.
Review in Cureus, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The implant-abutment connection is the mechanical and biological interface between the implant and the prosthesis, and its geometry influences mechanical stability, sealing of the microgap, stress distribution, and the peri-implant tissue response. This narrative review compares internal hexagonal connections with internal conical connections, of which the Morse taper is a specific deep-cone, friction-locking type, focusing on marginal bone loss and peri-implant clinical outcomes, and distinguishes laboratory and mechanistic evidence from clinical evidence. Laboratory, finite element, and microbiological studies suggest that conical connections may reduce micromovement, microgap opening, and bacterial and endotoxin leakage and may transmit occlusal load more favorably than screw-retained internal hexagonal connections. Systematic reviews and meta-analyses report that internal connections, and conical connections in particular, are associated with lower short- to medium-term marginal bone loss, yet several randomized controlled trials, including a 2025 trial, show no significant difference between connection types in marginal bone loss, peri-implant tissue health, complications, or survival, and both designs achieve high survival. Clinical outcomes are strongly influenced by implant placement depth, abutment height, bone quality, soft-tissue phenotype, platform switching, loading protocol, prosthesis design, oral hygiene, smoking, systemic health, and follow-up duration. On current evidence, connection-specific clinical superiority has not been consistently established. Internal conical connections may be considered when marginal bone preservation, interface stability, and esthetic stability are priorities, whereas internal hexagonal connections may be preferred when prosthetic flexibility, indexed positioning, and retrievability are required. Connection selection should be individualized and guided by patient risk, site factors, prosthetic requirements, and the evidence for the specific implant system rather than by connection geometry alone.
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Registered trials
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