Case Study of a Broken Instrument in a Primary Tooth and Literature Review

Root canal treatment is an important element of dental treatment, and broken instruments are one cause of endodontic treatment failure. Broken instruments are rarely reported in primary teeth because of their inherently wider and relatively straighter root canals. We describe a case of a patient with a broken instrument in a primary tooth and reviewed the literature across three databases.

A boy aged 7 years and 2 months was referred to our hospital because of pain persisting despite multiple dental treatments. Radiographic examination revealed a broken instrument in the maxillary right primary second molar. The patient experienced dental fear, so the treatment proceeded with the use of behavioral management and nitrous oxide, after which his pain disappeared. At the age of 9 years and 2 months, eruption of the successive permanent teeth was confirmed, and no pathological findings were observed except enamel hypoplasia. We undertook a literature review across three databases and found only two articles about broken instruments in primary teeth, neither of which described the eruption of the permanent teeth. All three cases involved primary molars.

We removed a broken instrument from the root of a primary molar and performed root canal treatment, resulting in a good outcome for the primary molar until it was replaced with successive permanent teeth. Although rare, broken instruments in the roots of primary molars do occur, and care should be taken during root canal treatment of primary molars.