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Published on: April 11, 2025
Comparison of Long vs. Short Concave Neck in One-Piece Implants Inserted 1 mm Subcrestally: A Pre-Clinical In Vivo
Hadi Antoun1, Frank Bonnet2, María Permuy Mendaña3,4
1Institut de Formation en Chirurgie Implantaire Avancée, Paris, France.
Objectives:
The aim was to assess the influence of one-piece implant concave neck height on soft- and hard-tissue healing on a canine model.
Material And Methods:
Monoblock implants with a transgingival concave neck were randomly inserted 1 mm subcrestally. Eight implants were characterized by a neck 2.8 mm long (group long) and eight implants by 1.8 mm (group short). After 3 months, the implants were retrieved and processed for histology. The quality and quantity of peri-implant tissues were investigated.
Results:
Histological analysis showed that all implants were osseointegrated, and peri-implant mucosa surrounded the abutment's surface in all 16 specimens. The qualitative analysis of soft tissues showed some differences among the groups. In particular, in the group "long", collagen fibers perpendicular to the implant's longitudinal axis were intertwined with the transverse fibers. Perpendicular fibers were detected in the same area as the short-neck implants, but the longitudinal fibers were less numerous and farther from the surface. No statistically significant differences were found in comparisons of soft and hard tissues between the short and long groups.
Conclusions:
After 3 months, no statistically significant quantitative differences were found between long and short concave necks for most of the measurements performed, although qualitative differences in collagen fiber orientation were observed.
