Why Does My Implant Crown Feel Loose? Causes and What to Do

There is a small titanium screw inside your implant, typically between 1.5 and 2 millimetres in diameter, and it is doing more work than anything else in the restoration. When an implant crown feels loose, that screw is the usual explanation.

Understanding how it works is genuinely useful, because it explains several things patients find puzzling: why a crown loosens years after it was fine, why simply tightening it is not a complete answer, and why the dentist replaces the screw rather than reusing it.

The abutment screw does not hold the crown on by wedging into a thread, in the way a screw holds a shelf to a wall. It works by preload.

When the screw is tightened to the manufacturer's specified torque, it stretches elastically — like a very stiff spring being pulled. That stretch generates a clamping force pulling the abutment down against the implant. The joint is held together by that clamping force, not by the screw threads themselves.

For the joint to stay stable, the clamping force must exceed the forces trying to separate the components during chewing. When it does, the joint behaves as a single unit. When chewing forces exceed it, the components separate microscopically with each bite, the screw gradually unwinds, preload is lost, and the crown starts to move.

Two consequences follow directly, and they are the answers to the most common questions:

Torque values are specific, not approximate. Each implant system specifies a torque — commonly somewhere between 15 and 35 Ncm depending on the system and the component. Under-tighten and there is insufficient preload. Over-tighten and the screw is stretched past its elastic limit, at which point it will not return and is liable to fracture. This is why a calibrated torque driver is used rather than hand feel, and why tightening it yourself at home is a genuinely bad idea.

A screw that has loosened once has already been stressed. It has been through cycles of loading that permanently altered it. Replacing it with a new screw and torquing to specification is standard practice for this reason.

Here is a detail that explains a specific pattern patients notice: a crown that loosens a few weeks or months after being fitted.

No machined surface is perfectly smooth. When two titanium components are brought into contact under load, the microscopic high points on each surface flatten against each other over the first hours and days. As they flatten, the components come very slightly closer together — and because the screw's stretch is what generated the clamping force, that small closing distance reduces the preload.

This is called the settling effect or embedment relaxation, and it can account for a meaningful percentage of the original preload. It is the reason many clinicians retighten the abutment screw after an initial period, and why a torque reapplied a few minutes after the first application often takes up further.

If a crown loosens shortly after placement, this is usually the mechanism, and it is not a sign that anything was done incorrectly.

Off-axis loading. An implant is strongest along its long axis. Force applied at an angle creates a lever, and the bending moment on the screw joint rises sharply with the offset distance. An implant placed at an angle, or restored with a crown whose biting surface sits off to one side, is loaded off-axis every time you chew. Our article on how implant angulation influences load distribution covers the mechanics, and how positioning errors affect bite forces years later covers the long-term consequences.

A cantilever. Where the crown extends beyond the footprint of the implant — to fill a wider space, or in a multi-unit restoration with a cantilevered unit — every millimetre of overhang multiplies the force on the screw.

Grinding and clenching. Parafunction applies high, sustained, and often lateral forces, in a pattern the restoration was not designed for. Bruxism and implant screw loosening covers this association, and dental implants and grinding covers the wider picture.

No periodontal ligament to absorb anything. A natural tooth sits in a ligament that allows perhaps 100 micrometres of movement and dissipates load. An implant is rigid, with movement measured in single micrometres. Everything is transmitted straight into the components. How implants transmit chewing pressure differently explains this.

A changed bite. A new crown placed on an opposing tooth, a filling that sits slightly high, or the loss of a tooth elsewhere in the arch can all redirect force onto the implant. This is why a restoration that was stable for years can start loosening after unrelated dental work.

A poor fit. If the abutment does not seat fully and passively on the fixture — because of a machining tolerance, a distorted framework in a multi-unit case, or debris in the connection — the joint carries a permanent internal stress before any chewing force is applied.

Cement-retained crowns have a second possible failure point. The cement lute degrades over time with thermal cycling, moisture and mechanical stress, and eventually loses its seal. This presents as gradual loosening, often with the crown coming off cleanly as a unit while the abutment stays put.

The trade-off between cement-retained and screw-retained restorations is a real one. Screw-retained crowns are retrievable — the access hole is unplugged and the crown lifts off — but the access channel must be positioned acceptably, which is not always possible on front teeth. Cement-retained crowns have no visible access hole but may need sectioning to remove, and excess cement left below the gum is a recognised cause of peri-implant inflammation. Our article on implant crown design and long-term maintenance covers the decision.

• Do not tighten anything yourself. Without a calibrated driver you will either under-tighten or over-stress the screw. A fractured screw inside a fixture is a substantially harder problem than a loose one.

• Do not use shop-bought cement. It traps the underlying problem and complicates retrieval.

• Stop chewing on it. Continued loading of a moving crown applies bending stress to an already compromised screw, which is how loose screws become fractured screws.

• Keep the crown if it has come off. Store it dry and safe, and bring it with you. Most can be refitted.

• Keep the area clean. Gentle brushing and normal interdental cleaning, unless painful.

• Note whether anything else has changed — recent dental work elsewhere, a new grinding habit, a change in how the bite feels.

• Arrange an appointment promptly. Within days, not weeks. If there is swelling, pus, fever, severe pain, or the implant itself moves, seek same-day care — see is a loose implant crown a dental emergency.

The crown is removed. For screw-retained restorations, the composite plug in the access channel is removed and the screw unwound. For cement-retained crowns, removal may require sectioning.

The components are then inspected for wear, distortion or fracture, and a radiograph confirms the abutment is fully seated on the fixture and shows the bone level around the implant.

A new screw is fitted and torqued to the manufacturer's specification, usually with a repeat application after a short interval to account for settling. The access channel is sealed — typically with PTFE tape or a similar material over the screw head, so it can be retrieved again, then composite over the top.

Then the important part: the cause is addressed. Occlusal contacts are checked and adjusted so the implant is not taking premature or lateral contact. The crown contour may be modified to reduce a cantilever effect. Where grinding is contributing, a night guard is discussed. Where positioning is fundamentally unfavourable, a remade crown — or in some cases a different restorative design — may be recommended.

Retightening alone resets a clock. Retightening plus addressing the loading is what stops it recurring.

Distinguishing all of this from genuine implant failure is a separate diagnostic exercise, covered in the difference between a loose crown and a failing implant.

Why does my implant crown keep loosening?

Repeated loosening almost always means the underlying loading problem has not been addressed. Common culprits are an unfavourable bite contact, a cantilever, grinding, or an implant angulation that loads the screw off-axis. It warrants investigation rather than another retightening.

Can the screw break?

Yes, and it is the main reason not to keep chewing on a loose crown. A fractured screw fragment inside the fixture requires careful retrieval, and retrieval can occasionally damage the internal threads of the implant.

Is a screw-retained crown better than a cement-retained one?

Each has advantages. Screw-retained crowns are retrievable and avoid the risk of residual subgingival cement. Cement-retained crowns allow more flexibility where the access channel would emerge somewhere aesthetically unacceptable. The choice is made case by case.

Does a loose crown damage the implant?

Not usually if addressed promptly. Prolonged micro-movement can allow bacterial ingress at the interface and, in some cases, contribute to inflammation of the surrounding tissue, so it is not something to leave.

How long should an implant crown last before this happens?

There is no fixed interval. Screw loosening is a recognised mechanical event over the life of a restoration rather than a defect, and single crowns in heavy-loading positions see it more often than others.

If an implant restoration has started to move, it is worth being seen within days — the repair is usually straightforward at that point and becomes less so if the screw fractures.

You can contact our team to arrange an appointment at our Wimpole Street practice. Our dental implants page explains implant treatment and aftercare.

This article provides general information about implant crown complications and does not constitute individual dental advice. Torque specifications, components and retrieval protocols vary between implant systems, and the cause of looseness in your case can only be determined by clinical examination with appropriate radiographs. Wimpole Dental is regulated by the Care Quality Commission, and our clinicians are registered with the General Dental Council.

Next review due: 10 August 2027