Implant Driver Hex Sizes: The Professional's Guide
Updated Jul 21, 2026
Every screw in implant prosthetics — cover screw, healing cap, abutment screw, prosthetic screw on a multi-unit — is turned by one small, heavily loaded interface: the driver tip seated in the screw head. Get that interface right and screw handling is uneventful for years; get it wrong and a routine delivery appointment turns into a stripped hex, a cammed-out driver or a retrieval procedure. This guide covers the dental implant driver types you will actually use, the common hex sizes in circulation (1.20, 1.25, 1.27 and 1.5 mm), which of our drivers fits which screw on the Internal Hex 2.42 platform, and how to control tightening torque properly.
This guide is written for licensed dental professionals — implantologists, restorative dentists and dental-lab technicians. It is general reference information: always follow the instructions for use (IFU) supplied with your components and instruments, and your own clinical judgment.
Why the driver–screw interface matters
The hex recess of a prosthetic screw is roughly a millimeter across, and the full tightening torque passes through it. Three failure modes make this small interface worth respecting:
- Cam-out. A driver that is tilted, worn or only partially seated climbs out of the recess under torque. Each cam-out event rounds the corners of the screw hex a little more, until the driver can no longer transmit torque at all.
- Stripped hex. Once the recess is rounded, the screw cannot be tightened — or worse, cannot be removed. Retrieving a stripped screw from inside an implant is delicate, time-consuming work, and in the worst case it costs the fixture its prosthetic connection.
- Aspiration and ingestion risk. Implant drivers are small metal instruments used over an open airway. An unsecured hand driver that slips out of the fingers, or a screw dropped from an unretentive driver tip, can be swallowed or aspirated. Ligate hand instruments with floss, use drivers with retentive (friction-grip) tips where available, and keep gauze screening and high-volume suction in place — standard practice, and worth restating.
All three risks trace back to the same discipline: use the correct interface size, seat the driver fully and passively before turning, and retire worn tips. A driver is a consumable, not an heirloom.
Driver anatomy and types
An implant driver has three functional zones: the connection end (a hand grip, a shank for a ratchet, or a latch shank for a contra-angle handpiece), the shaft, and the working tip whose geometry must match the screw recess exactly.
Hand drivers
A knurled grip with a fixed tip. Hand drivers give the best tactile feedback of any instrument in the sequence, which is why they are the right tool for try-ins, healing caps, cover screws and the initial seating of any prosthetic screw. Their limitation is deliberate: fingers on a small grip generate limited torque, so a hand driver alone cannot reach the defined values that definitive screws require.
Ratchet drivers
Short driver inserts with a shank that seats in a ratchet wrench — 6.35 mm (1/4") is the common shank dimension, including in our system. The ratchet arm multiplies hand force and, in its torque-indicating version, lets you stop at a defined Ncm value. This is the combination for final tightening of abutment and prosthetic screws.
Contra-angle (latch-type) drivers
Drivers with a latch shank for the contra-angle handpiece. Machine-driven screwdriving is faster for multi-screw cases and reaches posterior sites where a long hand driver has no interocclusal room. Use low speed and, where the unit supports it, the motor's torque limiter — a handpiece delivers torque without tactile feedback, so the settings do the feeling for you.
Hex, square and star interfaces
The hex socket is the dominant recess geometry in implant prosthetics, but it is not the only one. Some attachment and lab screws use a square recess; several systems use proprietary star-type (multi-lobe) geometries — Unigrip®-type drivers are the best-known example — which spread torque over more contact faces but only accept their own driver. A star or square screw will never drive correctly with a hex tip, and forcing it is the fastest way to destroy the recess.
Long vs short shafts
Most driver lines come in at least two shaft lengths. Short shafts are for posterior sites and patients with limited mouth opening, where every millimeter of interocclusal clearance counts. Long shafts reach deep subgingival screw heads — think multi-unit prosthetic screws under a full-arch framework — and keep the handle clear of the occlusal plane. Keep both on the tray; the case decides.
Common driver interface sizes in implant prosthetics
The table below maps the interface sizes you are most likely to meet. Descriptions reflect how these interfaces are commonly encountered across systems; always confirm the driver specification in the IFU of the screw you are turning.
| Interface | Where typically found | Matching driver at Dental Solutions |
|---|---|---|
| Hex 1.20 mm | Some internal-hex and narrow/mini-implant screw lines | Not required for our platform — verify per system IFU |
| Hex 1.25 mm | The most widespread prosthetic-screw interface; many internal-hex systems and many conical systems | Hand Driver Hex 1.25 and Hex Driver For Ratchet 6.35 |
| Hex 1.27 mm (0.050") | Systems and screw lines of inch-based lineage | A 1.25 driver commonly engages it in practice — verify full passive seating (see FAQ) |
| Hex 1.5 mm | Larger prosthetic, attachment and lab screws in several systems | Per system IFU |
| Star / multi-lobe (Unigrip®-type) | Proprietary geometry used by specific implant systems | System-specific driver required — no hex substitute |
| Square | Some attachment and laboratory screws; also the drive geometry of ratchet adapters | System-specific driver required |
Hex 1.25 on the Internal Hex 2.42 platform
Our entire prosthetic screw range on the Internal Hex 2.42 platform — abutment screws supplied with straight, angled and anatomic abutments, healing caps, cover screws and the prosthetic screws used at multi-unit level — drives with a single 1.25 mm hex interface. One hex size across the platform means one hand driver and one ratchet insert cover every screw you order from us, whichever prosthetic component the case calls for. (If you are still identifying the platform in the chart, start with our implant connection types guide.)
The working set looks like this:
- Hand Driver Hex 1.25 — try-ins, healing caps, cover screws and initial seating of every abutment and prosthetic screw on the platform.
- Hex Driver For Ratchet 6.35 — the same 1.25 hex tip on a 6.35 mm ratchet shank, for final tightening with a wrench.
- Motor Mount Driver For Handpiece — latch-type driver for contra-angle delivery of implants and components under motor control.
- Standard Ratchet Wrench 6.35 and Torque ncm Ratchet Wrench 6.35 — the wrenches that carry the ratchet insert; the torque version indicates Ncm so definitive screws are tightened to a value, not a feeling.
The same 1.25 hex logic applies at multi-unit level: the prosthetic screws that retain copings, temporary cylinders and Ti-bases on our multi-unit abutments all take the same drivers — see the multi-unit abutment guide for that workflow end to end.
Torque control: hand-tight, ratchet-tight and re-torque
Torque is what converts a screw into a clamp: the applied Ncm stretches the screw slightly and the resulting preload holds the joint together. Too little preload and the screw loosens under function; too much and you risk the screw or the recess. Practical torque control has four parts:
- Hand-tight has a real meaning. Fingers on a hand driver deliver on the order of 5–10 Ncm. That is the correct level for cover screws and healing caps, which only need to stay put during healing — commonly published ranges for these components sit around 10–15 Ncm, essentially firm hand tightening.
- Definitive screws need a number. For abutment and prosthetic screws, commonly published ranges in the literature run roughly 15–35 Ncm depending on screw dimension and application. For Dental Solutions Internal Hex 2.42 components, follow the value stated in the IFU supplied with each component, applied with a torque-indicating wrench — never a guess through a standard ratchet.
- Re-torque after 5–10 minutes. Under initial preload, the microscopic high points of the mating surfaces flatten (settling or embedment relaxation), and a portion of the preload is lost within minutes. Re-tightening to the same value after 5–10 minutes is commonly recommended practice to restore the intended preload before the restoration is put into function.
- Calibrate and maintain the wrench. A torque wrench is a measuring instrument with a spring mechanism that drifts with use and repeated sterilization. Follow the manufacturer's calibration schedule, clean and lubricate as instructed, and have the wrench checked or recalibrated periodically. Inspect driver tips under magnification: a rounded 1.25 tip strips screw recesses — replace it.
| Component (Internal Hex 2.42 catalog) | Typical tightening method | Commonly published range |
|---|---|---|
| Cover screws | Hand driver, hand-tight | ~10 Ncm |
| Healing caps | Hand driver, hand-tight | ~10–15 Ncm |
| Definitive abutment screws | Torque wrench + ratchet hex driver | ~25–35 Ncm |
| Prosthetic screws at multi-unit level | Torque wrench + ratchet hex driver | ~15 Ncm |
These are commonly published orientation ranges, not brand specifications — the IFU supplied with each screw is always the governing document.
Building your driver and torque set
A complete screwdriving set for the Internal Hex 2.42 platform is four instruments: the hand driver, the ratchet insert, a torque wrench and a contra-angle driver for machine-driven cases. All are in our tools category, manufactured under ISO 13485 like the rest of the catalog. Practices equipping a full surgical setup can take the Premium Surgical KIT With Torque Ratchet, which packs the drill sequence and driver set with a torque ratchet in one cassette. Shipping is a flat $50 worldwide and free over $350, with transit time confirmed for the destination and service at checkout, with a 10-day return window on new, unopened products. If you are weighing original versus compatible instrumentation more broadly, our OEM vs compatible components guide covers the decision framework.
Frequently asked questions
Does a 1.25 mm hex driver fit a 1.27 mm screw?
Usually yes in practice — but they are nominally different interfaces, so verify seating before you torque. A 1.25 mm driver commonly engages a 1.27 mm (0.050") recess because the difference is only 0.02 mm; general practice is to accept the pairing only when the driver seats fully and passively, with no perceptible rock. A driver that wobbles or engages only at the top of the recess concentrates torque on the hex corners and will strip the screw. This is general practice knowledge, not a manufacturer specification — when in doubt, use the driver stated in the screw's IFU.
What hex size do Dental Solutions screws use?
1.25 mm, across the platform. Every cover screw, healing cap, abutment screw and multi-unit prosthetic screw in our Internal Hex 2.42 catalog drives with the same 1.25 hex — one hand driver and one ratchet insert cover the entire range.
Do I need a torque wrench, or is hand tightening enough?
Both, for different screws. Hand tightening is correct for cover screws and healing caps (~10–15 Ncm territory). Definitive abutment and prosthetic screws need a defined value — commonly published ranges run about 15–35 Ncm — which only a torque-indicating wrench can deliver repeatably.
How often should a dental torque wrench be calibrated?
Follow the wrench manufacturer's stated schedule; periodic verification is commonly recommended, and more frequent checks make sense under heavy use and repeated sterilization cycles, which are exactly the conditions that drift a spring mechanism. A wrench that has been dropped should be checked before it is trusted again.
How do I prevent a driver or screw being aspirated?
Secure everything that goes over the airway: tie a floss ligature to hand drivers, prefer retentive (friction-grip) driver tips that hold the screw, place a gauze screen distal to the working field, and keep high-volume suction ready. It is basic practice, and it is the cheapest complication insurance in implant dentistry.
Unigrip® is a registered trademark of Nobel Biocare Services AG. All brand names mentioned are trademarks of their respective owners; Dental Solutions is not affiliated with, endorsed by, or sponsored by any of these companies. Compatibility refers to mechanical fit with the referenced interface.