If you've ever glanced at your torque wrench readout and just gone with a number that "felt right," this one's for you. Insertion torque isn't a single pass/fail line - it's a scale, and where you land on it should decide what you do next. Here's the breakdown, along with the research behind each call.
What torque actually measures
Insertion torque is the resistance the bone gives as the implant seats, measured in Newton-centimeters (Ncm). It's a proxy for primary stability: how mechanically locked-in the implant is the moment you finish placing it. That number matters because it's the first of two stability phases an implant goes through. Primary stability comes from mechanical friction against bone at placement; secondary stability comes later, from actual bone remodeling and osseointegration. Between those two phases there's a well-documented dip, a window where mechanical stability is fading before biological stability has caught up. Torque at placement is your best early read on how much of a cushion you have going into that dip.
The scale, zone by zone
0–15 Ncm - cover screw. At the low end, the implant isn't ready to carry any load. A 2019 split-mouth histomorphometric trial (Amari et al., International Journal of Implant Dentistry) compared very-low-torque placement against implants seated around 30 Ncm and found both can integrate, but the authors specifically recommend submerged healing under a cover screw at the lower end, especially in softer bone, rather than leaving it exposed.
15–35 Ncm - healing abutment. Once you're in this range, a stock or custom healing abutment is reasonable. That same Amari 2019 study is the reason: implants placed around 30 Ncm and left non-submerged with a healing abutment showed good bone-to-implant contact at eight weeks - trending even higher than the very-low-torque group. It's the same trial supporting both calls because it's the one that actually compared these torque levels head-to-head.
35–45 Ncm - the immediate-load sweet spot. This is where confident immediate provisionalization becomes reasonable. A study in the International Journal of Oral & Maxillofacial Implants (Ottoni et al., 2005) found implants placed at 32 Ncm or higher integrated successfully under immediate loading, while implants placed at only 20 Ncm failed in 9 out of 10 cases. That gap is the clinical argument for treating this range as the real threshold for going immediate.
45–70 Ncm - upper arch yes, lower arch with a caveat. This range holds up well on the maxilla. On the mandible, the same number carries more risk, not because a trial showed higher failure rates there, but because of bone density. The mandible is denser bone, and torque scales with density: the denser the bone, the higher the torque for the same amount of physical resistance. Research on the density-torque relationship (Venkatakrishnan et al., 2017, Biomedical and Pharmacology Journal) points to impaired local blood vessel formation and osteocyte death under that kind of compressive stress in dense bone - so treat this as a mechanism-based caution rather than a "lower arch implants fail more" claim.
70+ Ncm - bone compression risk. Past 70, you're in a different category of concern. Excessive compression during insertion can exceed what bone can tolerate and cut off local blood supply to the area — and a 2024 review (Ramesh et al., Clinical, Cosmetic and Investigational Dentistry) walks through that exact mechanism, describing non-viable bone visible on histology within the first month when compression necrosis occurs.
Why the number is worth more than a passing glance
Torque isn't just about whether the implant went in "tight enough." Too little, and you risk micromotion during healing before bone has a chance to form. Too much, and you risk compressing and damaging the bone you're relying on to integrate around the implant in the first place, plus added mechanical stress on the implant's internal hex and screw preload that can show up later as loosening or component fatigue. The right torque, for a given bone density and clinical goal, is what lets you skip straight to the correct next step instead of guessing.
The full citation list and study details are in the attached PDF - worth keeping on hand chairside.