Hex vs Torx vs Unigrip: How to Identify an Implant Driver Tip
Every stripped abutment screw starts the same way: a driver that almost fit.
It seated. It turned. It even held for a while. Then it slipped, and the hex inside the screw head is now round, and a two-minute re-torque has become a retrieval.
Implant driver tips are small, the differences between them are smaller, and nobody labels the screw. Here is how to tell hex, Torx-style, and Unigrip tips apart by sight and by feel, how to match a tip to an implant you did not place, and how to know when a tip itself is the problem.
Need a specific brand? Our implant driver size guide covers the major systems, and the compatibility chart covers 85+ more. This post is about identifying and using the tip once you are holding it.
The three connection families at a glance
| Hex | Torx-style (SCS / ITI) | Unigrip (Nobel-style) | |
|---|---|---|---|
| Tip profile | Six flat sides, sharp corners | Six-point star | Proprietary Nobel geometry |
| What you see in the screw | A hexagonal recess | A star-shaped recess | Nobel's own recess shape |
| How it grips | Contact on six flat faces | Contact on the star points | Designed to match Nobel screws only |
| Typical systems | Most systems (Zimmer, BioHorizons, MIS, Osstem, Dentium, and many more) | Straumann and ITI-compatible systems | Nobel Biocare and Nobel-compatible systems |
| Sizes | 0.9, 1.0, 1.2, 1.25, 1.27, 1.4 mm and others | One common size | One common size |
If you remember one thing: the family is easy to identify. The size, within the hex family, is where mistakes happen.
How to identify a driver tip by sight
Hex tips
Look straight down the end of the tip. Six flat faces meeting at six defined corners. Most universal kits mark the size on the tip shaft or with color on the tip, and many store each size in a labeled slot.
Torx-style tips
Six points instead of six flats. The star profile is obvious from the end, even at a glance. There is essentially one size to worry about in dentistry, which makes this the easiest tip to get right.
Unigrip tips
Nobel's own geometry. It does not look like a hex or a clean star, and neither of those will seat properly in a Nobel screw. If a restoration was placed on a Nobel system, reach for this tip first.
Short vs long
Each tip usually comes in two lengths. The connection is identical. Length is about access: short where you can reach easily, long for posterior sites or deep access channels. Driver length has nothing to do with torque.
Telling hex sizes apart: the part you cannot eyeball
A 1.2 mm and a 1.25 mm hex look the same across a tray. So do 1.25 and 1.27. The difference is a few hundredths of a millimeter, which is exactly the tolerance that decides whether a tip grips or rounds out a screw.
Two things help:
- Know that 0.050 inch has two names. 0.050" converts to 1.27 mm, but many manufacturers and charts call the same class of driver 1.25 mm. That is why charts seem to disagree. Treat them as one family, and let fit decide.
- Let fit decide. The feel test below is the tiebreaker for every close call.
The feel test: how a correct tip seats
Before you apply any real torque, seat the tip and check three things:
- It goes all the way in. The tip bottoms out in the screw recess. A tip that stops short is too big or the recess is packed with debris.
- It does not rock. Wiggle the driver gently side to side. A correct tip feels locked in. Noticeable play means the tip is too small or worn.
- It does not spin before engaging. Turn gently. A correct tip engages immediately. If it rotates freely before catching, it is the wrong size and will round the recess under load.
Fails any of the three? Stop and try the next size. A tip that almost fits is the most dangerous tip in the kit.
Matching a tip to an implant you did not place
The patient does not know the brand. The records are elsewhere. Here is the order to work in:
- Try to identify the system first. Check the chart, call the previous office, or compare the radiograph against implant identification references. Knowing the system is always better than guessing.
- Look into the access channel. Clean it out, then look at the recess shape. Hex, star, or something else narrows it immediately.
- Trial gently, most common first. For a hex recess, try 1.25/1.27 first, then 1.2, then the outliers (0.9, 1.0, 1.4). Use finger pressure only. Stop at the first tip that passes the feel test.
- Write it down. Record the system and the tip size in the patient's chart so nobody repeats the search next time.
Never force a tip that does not seat. If nothing fits cleanly, the implant may use a size outside a standard kit, and the manufacturer's driver is the right tool.
Cam-out: how a screw gets stripped
Cam-out is when the driver rides up and out of the recess under torque instead of turning the screw. It happens for three reasons:
- Wrong size. Too small a tip only contacts the corners of the recess, and those corners round off.
- Not fully seated. Partial engagement concentrates force on the top edge of the recess.
- Off-axis pressure. Driving at an angle levers the tip out, which is common in the posterior, where access forces the angle. A right-angle driver helps by letting you keep the tip in line with the screw.
Once a recess is rounded, the right driver no longer grips it either. That is the moment a routine appointment turns into a retrieval. Every step above exists to prevent it.
When the tip is the problem
Driver tips wear. Every seat, every torque cycle, and every sterilization cycle takes a little off the edges. A worn tip behaves like an undersized one.
Inspect under magnification and replace when you see:
- Rounded hex corners instead of sharp ones
- Dulled or chipped star points
- A bent or twisted shaft
- A tip that used to pass the feel test and now rocks
- Any slip during normal use
A worn tip costs far less to replace than a stripped prosthetic screw. The 16-tip Implant Driver Tips set is sold on its own, and replacement heads are available for the Variable Torque Driver.
Keep every tip where you can find it
Tip mix-ups mostly happen in drawers: loose tips, no labels, and three nearly identical hex sizes rolling around together. We call that Kit Sprawl. The fix is one organized set with a labeled position for every tip.
The Taft Variable Torque Driver includes 16 tips (0.9, 1.0, 1.2, 1.25, 1.27, and 1.4 mm hex, plus Nobel-style and Straumann-style, each in short and long), a right-angle head that helps keep the tip in line with the screw, and click-stop torque from 10 to 35 Ncm. $439 direct with a 60-day money-back guarantee. Prefer a color-coded box with every mandrel in its own slot? That is the Universal Rainbow Torque Box.
Not sure which tip fits a system you are seeing? Call 513-580-8414 or email sales@taftdentalco.com and we will tell you.
Common questions
How do I know which driver tip fits an implant screw?
Identify the implant system if you can, then use a compatibility chart. If the system is unknown, look at the recess shape (hex, star, or Nobel-style), then trial tips gently from most to least common. The correct tip seats fully, does not rock, and does not spin before engaging.
What is the difference between a hex and Torx implant driver?
A hex driver has six flat sides and is used by most implant systems in several sizes. A Torx-style driver has a six-point star profile and is used mainly by Straumann and ITI-compatible systems. They are not interchangeable.
What is a Unigrip driver?
Unigrip is Nobel Biocare's proprietary driver geometry, used across Nobel systems and some Nobel-compatible implants. Hex and Torx-style drivers will not seat correctly in a Nobel screw.
Why did my driver strip the screw?
Usually cam-out: the tip was the wrong size, was not fully seated, was worn, or was driven at an angle. Any of these concentrates force on the edges of the screw recess and rounds it out.
How often should implant driver tips be replaced?
There is no fixed schedule. Inspect tips regularly under magnification and replace them when corners round, points chip, the shaft bends, or a tip that used to seat firmly starts to rock or slip.
Professional Use Only. Licensed Dental Professionals. General information only. Always verify driver compatibility and torque values against the implant manufacturer's instructions for use.