Root tip fracture can occur during the extraction of teeth. The clinician must then decide to either leave the root fragment in situ, or to attempt its removal. A similar decision is made when retained root fragments are found incidentally on oral radiographs. The prevalence of retained root fragments is reported as 11-37%.
Risks of attempting root tip removal
Before pursuing a fractured root tip or a retained root fragment, a risk-benefit analysis should be considered. 'There are occasions when leaving the root is one of the most prudent and sound clinical decisions one can make.
Roots may displace into surrounding anatomical structures such as the maxillary antrum  and lingual pouch,and their removal can damage adjacent teeth or the inferior alveolar nerve. The risk of an oral-antral fistula increases with age due to the increased density of alveolar bone and pneumatisation of the maxillary sinus reducing the distance interval between the root tips and the maxillary sinus.
When root tips fracture during challenging extractions, prolonged operative times may increase the risk of alveolar osteitis. Parthasarathi in 2011 found a statistically significant correlation (P = 0.003) between intra-operative root fracture and alveolar osteitis, but other studies have failed to demonstrate a link Interestingly, the surgical removal of teeth doesn't increase the risk, leading clinicians to believe that the absolute force applied is more significant than the duration of extraction.
Benefits of retaining roots
Submergence of vital roots has been shown to maintain alveolar bone for prosthodontic purposes Decoronatedankylosed teeth can be used to preserve alveolar bone width and height for future implant placement. The ankylosed teeth are decoronated 2 mm below alveolar bone to allow for wound closure and healing as demonstrated by earlier studies. Ideally conventional root filling materials will not be present to cause an inflammatory reaction. Implants have been shown to successfully integrate around vital root fragments with cementum apposition directly between the implant and fractured root surface.
Coronectomy was first advocated by Knutsson in 1989 as the intentional retention of roots where third molars are close to the inferior alveolar nerve (IAN). It was shown by Renton in 2012 that for a successful coronectomy, root tips should not be mobilised during the procedure and there must not be any bacteria present in the pulp before decoronation  Migration away from the IAN occurred in 2-5% of roots after 2-5 years, with most migration in the first three months and roots displacing 2-3 mm after 1-2 years.
The decision to remove retained root fragments either found incidentally on radiographs or those roots that have fractured intra-operatively during tooth extraction procedures needs to be made on a case-by-case basis. The advantages and disadvantages of surgery vs. non-surgery must be taken into consideration. The authors recommend a pragmatic approach of 'non nocere' – 'do no harm'.