The Conometric Prosthesis Let Go More Often.

Retention systems in implant prosthodontics tend to acquire reputations the way politicians do: one is praised for its discipline, another for its elegance, and both become exhausting the moment something falls off. In Incidence Of Complications In Immediate Loading Conometric Vs Screw-Retained Full-Arch Prostheses: Retrospective Study On 1356 Implants, Leonello Biscaro and colleagues ask the sensible question lurking beneath the marketing language. When a complete immediate-loading rehabilitation is retained conometrically rather than with screws, what actually happens in practice?

The answer is not dramatic, which is often a relief. Survival and overall prosthetic success were broadly similar. The awkwardness arrived elsewhere: conometric prostheses detached more often.

The Data Anchor

This was a retrospective study of 203 patients treated with complete immediate-loading prostheses supported by 1,356 implants and 261 fixed prostheses. Of those restorations, 65 used conometric retention and 196 were screw-retained. The mean follow-up was 28.5 months, with a range of 12 to 80 months.

The authors evaluated implant survival, prosthesis success, and both technical and biologic complications. That matters because immediate full-arch prosthodontics is not improved by airy declarations that a system is “promising.” It is improved by knowing which kind of nuisance is most likely to turn up later, preferably before the nuisance introduces itself chairside.

Key Findings

• Implant survival stayed high, regardless of retention choice. During follow-up, 27 implants failed, which amounted to an overall implant failure rate of 2%, with no statistically significant difference between conometric and screw-retained groups.
• Overall prosthetic success was respectable but not immaculate. The global prosthetic success rate was 89.3%, again without a significant difference between the two retention systems.
• Screw loosening remained the profession’s dependable houseguest. It was the most frequent complication, occurring in 4.2% of cases, followed by chipping or fracture of the veneering material.
• The conometric catch was detachment. Prosthesis loss of retention occurred in 9.2% of conometric prostheses, and this was the signal that separated the groups in a clinically meaningful way.
• So the trade is not survival versus failure, but nuisance versus nuisance. The conometric approach did not collapse the treatment model; it simply came with a greater tendency to let the prosthesis part company with its appointed position.

💡 The Clinical Bottom Line

If you are choosing between conometric and screw-retained retention for an immediately loaded full-arch case, this paper suggests you should stop expecting a morality play. One system is not saintly and the other wicked. Both can work. But conometric retention appears to buy its screwdriver-free neatness with a higher chance of detachment.

That is the sort of trade-off a clinician can live with, provided it is named honestly beforehand. Nothing ruins a prosthodontic romance faster than discovering that the thing which looked elegantly simple in theory has become intermittently detachable in real life.

Dr Samuel Rosehill is a general dentist with a prosthodontic focus, practising at Ethical Dental in Coffs Harbour, NSW. He holds a BDSc (Hons) from the University of Queensland, an MBA, an MMktg, and an MClinDent in Fixed & Removable Prosthodontics (Distinction) from King’s College London.

Reference: Biscaro L, Canullo L, Spanu O, Zuffanti A, Pesce P, Menini M. Incidence Of Complications In Immediate Loading Conometric Vs Screw-Retained Full-Arch Prostheses: Retrospective Study On 1356 Implants. International Journal of Oral & Maxillofacial Implants. 2025;40. DOI: 10.11607/jomi.11316