A deep and multi-helix flute threaded implant: a review and clinical analysis

Abstract

Objectives: Implant success depends on osseointegration that is influenced by macrogeometry, including thread design. Thread macrogeometry has a crucial role in achieving primary stability, particularly in low-density bone. Our study reviews the thread design's impact on implant stability, focusing on Straumann BLX (Straumann Co.) implants for practical insights.

Materials and methods: We searched the PubMed/MEDLINE and Embase for studies released until August 2023 using the following keywords: "implant", "macrogeometry", "thread", "thread depth", "thread pitch", "thread geometry", "macrodesign", "flute", "osseointegration", and "stability". In addition, 58 Straumann BLX implants with dynamic threads, which feature a deep thread design and incorporate a multi-helix flute structure to enhance primary stability across different bone densities, were reviewed retrospectively at our institute.

Results: The literature demonstrated that thread pitch, depth, and flute design significantly affect stress distribution and initial stability, especially in low-density bone. Implants with deep threads and spiral flutes showed improved primary stability and insertion efficiency. Clinically, retrospective data from 58 cases supported favorable outcomes in challenging bone conditions such as posterior maxilla and implant replacement sites.

Conclusion: We need to determine appropriate designs for implants with the consideration of bone quality and implantation bed condition.

Keywords: Dental implants; Macrogeometry; Osseointegration; Stability; Thread depth.

Fig. 1

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow diagram illustrating the selection process of studies for the systematic review.

Fig. 2

Various implant thread designs: A. Microthread design. B. Progressive thread design with increasing depth. C. Variable threads. D. Deep threads. E. Knife threads. F. Multiple helix and variable thread design.

Fig. 3

Distribution of implants based on diameter, length, and location. A. Diameter distribution of implants. B. Length distribution of implants. C. Location distribution of implants. (Post. Mn.: posterior mandible, Ant. Mn.: anterior mandible, Post. Mx.: posterior maxilla, Ant. Mx.: anterior maxilla)

Fig. 4

Distribution of reasons for edentulous areas, categorized by factors such as implant failure, chronic periodontitis, osteomyelitis, and other pathologies.

Fig. 5

Straumann BLX (Straumann Co.) installation at the extraction site of an endo-periodontal lesion. A preoperative panoramic view showed a periapical lesion at site #37 (A). A bone graft was performed at site #37 (B). The fixture was installed with a covers crew (C-E). Re-entry at site #37i was done 5 months after the implant installation (G, H). The final prosthesis was delivered (I).

Fig. 6

Straumann BLX (Straumann Co.) installation at the site of an implant failure. The implant fixture at site #25 was lost (A, B). Endoscopic examination revealed granulation tissue associated with peri-implantitis (C). The previously grafted maxillary sinus site appeared to be healthy (D). A new implant was placed at the failed implant site, #25 (E, F).