Has the implant broken, or is it the screw, the abutment or the crown?

A conventional implant treatment is made up of four layers. At the bottom is the implant body that sits in the bone, on top of it the connecting part that comes out through the gum (the abutment), a small screw that fastens this part or the bridge to the body, and at the very top the crown or bridge that you can see. The feeling that something 'has broken' can come from any of these four layers, and looking from inside the mouth, most of the time they all look the same. In one-piece designs, because the body and the upper section are the same piece, there is no separate abutment screw; the list of possibilities is shorter.

The problems encountered most often are in the upper layers. In a review combining studies with follow-up of more than five years, screw loosening was seen in 8.8 per cent and facing fracture in 3.5 per cent of single-tooth implant crowns over 5 years. In bridges supported by more than one implant, the most common problem over 5 years was facing fracture (13.5 per cent); it was followed by loosening of a screw or an abutment (5.3 per cent). Most of these are jobs that are solved on the prosthetic side, without touching the implant.

A fracture of the abutment screw is one step more serious. The screw generally comes loose first; when chewing continues with a loose screw, the load falls directly on the screw and the screw fatigues and breaks. The broken piece stays inside the implant. A 2026 systematic review examining techniques for removing fractured screws found that most of the evidence comes from laboratory studies and case reports, that the success rate in the laboratory was 86 per cent, and that how deep the screw had fractured markedly affected the result. When it cannot be removed, the implant may need to be replaced.

A fracture of the implant body itself is rare. In a study in Sweden that examined 10,099 implants in 2,670 patients, 44 implants (0.44 per cent) fractured; the fractures occurred at 95 months on average, that is, at about 8 years, and half of them were seen between years 2 and 8. In 7,712 implants placed at the University of Toronto over 41 years, the fracture rate after loading was 0.35 per cent, and fracture occurred on average 10.6 years after loading. In other words, this is a problem encountered years later rather than in the first months.

The factors that make fracture more likely are largely to do with repeated load. In the Swedish study, clenching and grinding at night (bruxism) was the factor that increased the risk of fracture the most; being next to the section of a bridge extended beyond the last implant (the cantilever) also increased the risk, and as implant diameter increased the risk fell markedly. In the same study, each 1 mm increase in implant length increased the likelihood of fracture by 22.3 per cent, while higher-grade titanium reduced it by 72.9 per cent; these are associations that emerge from a retrospective record and do not show causation. In Toronto, fractures stood out in narrow-diameter implants (3.75 mm and below), at the back of the lower jaw, in bridges with a long cantilever and in some implant designs that the authors considered unfavourable. In a record of 18,700 implants in Iran, 94.6 per cent of the fractures were in the premolar and molar region.

The effect of clenching has been examined separately. In a 2025 meta-analysis, in patients with bruxism the likelihood of implant fracture was found to be about 16 times higher, the likelihood of abutment fracture about 14 times higher and the likelihood of screw fracture about 7 times higher (odds ratio). These are observational studies; they do not prove on their own that bruxism causes fracture, but they explain why it is the first piece of information asked for in planning. In a study in Japan in which 1,126 implants of a single brand were followed for about 10 years, on the other hand, single crowns not splinted to each other, male sex and an angle of the lower jaw of less than 120 degrees on a panoramic X-ray were the factors that increased the risk of abutment or implant fracture.

There is usually a warning before a fracture. A screw that comes loose again and again, the crown moving, a feeling of a 'click' when chewing or repeated facing fractures in the same area show that the load at that point is too great. Adjusting the bite, a night guard or a review of the bridge design at this stage is the most effective way of preventing the next fracture.

The distinction below gives a preliminary idea; the definite answer comes from an examination and an X-ray. If you have one of the signs in the second list, do not put off the appointment.

The order matters: first an emergency is ruled out, then the layer that has broken is identified, and last of all the cause is discussed. A repair made without discussing the cause brings the same fracture back.

1. 1

   You are asked about a swallowed or inhaled piece

   If the piece is missing and there are swallowing or breathing symptoms, the assessment is carried out in A&E. On objects swallowed or inhaled during dental treatment, Guy's and St Thomas' hospital writes that a piece that has gone into the airway has to be removed.

2. 2

   Examination and X-ray

   The crown and bridge are examined, and the gum around the implant and the bone level are checked. An X-ray shows the integrity of the screw, the abutment and the body; if you have old X-rays, take them with you for comparison.

3. 3

   The prosthesis is removed

   In a screw-retained system, the crown or bridge is taken off and the body is assessed separately. In cemented systems this is more laborious, and sometimes the crown has to be cut.

4. 4

   The fractured screw is removed

   The review recommends starting with hand instruments for accessible fractures and moving on to ultrasonic or modified instruments if necessary. If it is removed without damage to the implant's internal threads, the prosthesis is refitted with a new screw and, if necessary, a new abutment.

5. 5

   If the body has fractured, the plan changes

   Of the 27 fractured implants in Toronto, 19 were removed, 6 were left in the bone and covered over, and 2 were modified and used with a new prosthesis. Which is chosen is determined by the remaining bone, the site of the fracture and the neighbouring structures.

6. 6

   The cause is discussed

   You are asked about clenching, a section of the bridge extended towards the back, a narrow-diameter implant, an unsplinted single crown and points that make early contact in the bite. If necessary the bite is adjusted, a night guard is made or the bridge design is changed.

The options vary with the part that has broken; moving from one to another usually depends on the result of the first attempt.

The following are behaviours that turn a small repair into a big job.

The process varies with the layer that has broken. The common point is that a repair whose cause has not been addressed does not last.

1. If the screw was tightened or renewed

   Most often you return to normal use the same day. If the bite was adjusted as well, biting may feel different for a day or two; having the screw checked again a few weeks later is ordinary.

2. If the crown or the facing was renewed

   You can manage with a temporary crown during the impression and laboratory stage. When the new crown is fitted, the bite is checked in particular.

3. If the fractured body was removed

   Healing of the area takes weeks. During this time, how the bone is healing is monitored; the site and timing of the new implant are decided after this assessment.

4. The long term

   In a system that has had a fracture, check-ups become more frequent. If you clench, the night guard should be renewed as it wears; the screw and the facing should be reviewed at every check-up.

The same complaint that something 'has broken' can correspond to very different jobs, from a short screw procedure to the implant being done again. The items that determine the scope:

The layer that has broken

The facing, the screw, the abutment and the body are very different jobs from one another. The distinction becomes clear after an examination and an X-ray.

Availability of the part

If the system is known, a replacement screw and abutment are obtained quickly. If the system is not known, or has been withdrawn from the market, the same job takes longer and can grow.

The depth of the fractured screw

Fractures close to the surface are removed more easily. With deep fractures the success rate falls and replacing the implant may come into it.

Correcting the cause

A night guard, adjusting the bite or a change to the bridge design is part of the repair. If it is skipped, the same fracture recurs.