Exploring Mandibular Wisdom Teeth Roots after Coronectomy

Coronectomy involves the removal of part of the mandibular wisdom teeth but retention of the root. It is believed to cause less risk to the inferior alveolar nerve than extraction. An article on this topic titled “Histological evaluation of mandibular third molars roots retrieved after coronectomy,” appears in the 2015 British Journal of Oral and Maxilofacial Surgery and written by Vinod Patel and et. al (vol. 52, pp. 415-419).

In the article the authors sought to find out the pulpal and periradicular status of retained roots of mandibular wisdom teeth and histologically evaluated coronectomy roots that were removed because of persistent symptoms. It is possible the roots had become infected. A total of 21 patients (with 26 roots) were included in their study with persistent symptoms after the roots had been retrieved. Of the 26 symptomatic roots, radiographic assessments showed coronectomy had been sufficient in twenty, but a shard of enamel had been retained on the root fragment in six. All roots were retrieved with no complications except for 1 which had persistent dsyfunction of the nerve.

In their discussion the authors sate

“This report is seminal as it shows that all the roots retrieved had a vital vascularised pulp, and in all cases the periradicular soft tissues were not inflamed. The data therefore suggest that symptoms after coronectomy do not result from loss of pulpal vitality or subsequent periradicular inflammation…Our findings are supported by animal studies, which showed that root fragments with vital pulps were maintained in the alveolus without any inflammatory reaction. Furthermore, removal of asymptomatic retained root tips in humans histologically confirmed the lack of any inflammatory infiltrate.”

The authors feel that only certain teeth should be selected for coronectomy and those teeth should be sound and have evidence of caries, or pulpal, periodontal, or orapical disease. The authors present two common situations that can occur after coronectomy. If patients have symptoms but clinical and radiological examinations show the sites have healed then the wisdom tooth origin should be revisted. If there is a radiolucent area below the root this indicates apical disease but there is a possibility that root migration has occured. From their study the authors feel that there is no possibility for late infection caused by loss of pulpal vitality in the retained root after performing coronectomy.

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