Trial reportJournal of periodontology2025
Histological and immunohistochemical soft-tissue response to cylindrical and concave abutments: Multicenter randomized clinical trial.
Trial report in Journal of periodontology, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers, 1 of them a synthesis that pooled it.
What it found
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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
6 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Influence of Concave Versus Convex Emergence Profiles on Midfacial Mucosal Stability-A Systematic Review With Meta-Analysis.Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.] · 2026Pooled it
- Influence of Abutment Shape on Implant Marginal Bone Remodeling: A Double-Blind, Randomized 24-Month Clinical Study.Clinical oral implants research · 2026Trial
- Histological and immunohistochemical soft-tissue response to cylindrical and concave abutments: Multicenter randomized clinical trial.Journal of periodontology · 2025Trial
- Peri-Implant Supracrestal Resiliency (PSR): A Geometric Determinant Guiding Emergence Profile Execution.Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.] · 2026Article
- Quantitative analysis of peri-implant collagen fiber orientation around external hexagon and Morse taper implant connections: A dog model study.Journal of clinical and experimental dentistry · 2026Review
- Histologic Analysis of Peri-implant Soft Tissue Around External Hexagon and Morse Taper Implant Connections.Journal of clinical and experimental dentistry · 2026Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
12 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundThis study aimed to analyze the influence of concave and cylindrical abutments on peri-implant soft tissue. Dimensions, collagen fiber orientation, and immunohistochemical data were assessed.
methodsA multicenter, split-mouth, double-blind randomized clinical trial was conducted. Two groups were analyzed: cylindrical abutments and concave abutments. After a 12-week healing period, peri-implant soft tissue samples were collected, processed, and evaluated for dimensions, collagen fiber orientation, and immunohistochemical data. Inflammatory infiltration and vascularization were assessed, and the abutment surfaces were analyzed using scanning electron microscopy. The statistical analysis was performed using the SPSS version 20.0 statistical package.
resultsA total of 74 samples in 37 patients were evaluated. Histological evaluation of peri-implant soft tissue dimensions revealed significant differences between concave and cylindrical abutments. Concave abutments exhibited greater total height (concave: 3.57 ± 0.28 - cylindrical: 2.95 ± 0.27) and barrier epithelium extension (concave: 2.46 ± 0.17 - cylindrical: 1.89 ± 0.21) (p < 0.05), while the supracrestal connective tissue extension (concave: 1.11 ± 0.17 - cylindrical: 1.03 ± 0.16) was slightly greater (p > 0.05). Collagen fiber orientation favored concave abutments (23.76 ± 5.86), with significantly more transverse/perpendicular fibers than for cylindrical abutments (15.68 ± 4.57). The immunohistochemical analysis evidenced greater inflammatory and vascular intensity in the lower portion for both abutments, though concave abutments showed lower overall intensity (concave: 1.05 ± 0.78 - cylindrical: 1.97 ± 0.68) (p < 0.05). The abutment surface analysis demonstrated a higher percentage of tissue remnants on concave abutments (42.47 ± 1.32; 45.12 ± 3.03) (p < 0.05).
conclusionsWithin the limitations of this study, concave abutments presented significantly greater peri-implant tissue height, linked to an extended barrier epithelium, versus cylindrical abutments in thick tissue phenotype. This enhanced soft tissue sealing, favoring a greater percentage of transversely oriented collagen fibers. The concave design reduced chronic inflammatory exudation with T and B cells, thus minimizing the risk of chronic inflammation. PLAIN LANGUAGE SUMMARY: This study looked at how 2 different shapes of dental implant abutments (the parts that connect the implant to the crown), specifically concave and cylindrical, affect the soft tissue around the implants. We wanted to see how these shapes influenced the tissue's size, structure, and health. We conducted a clinical trial with 37 patients, comparing the 2 types of abutments in the same mouth over 12 weeks. Our findings showed that the concave abutments led to a taller and more extensive layer of protective tissue around the implant compared to the cylindrical ones. This protective tissue had more favorable collagen fiber orientation, which is important for the strength and health of the tissue. Additionally, the concave abutments resulted in less inflammation and better tissue integration. In conclusion, concave abutments may provide better support and health for the soft tissue around dental implants, reducing the risk of chronic inflammation and potentially leading to better long-term outcomes for patients with dental implants.
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