The case
Liu, Zhou, and colleagues report a 25-year-old female patient with a mandibular right canine that had pulp necrosis, a blunderbuss open apex, and a large periapical radiolucency. The tooth is described in International Endodontic Journal (DOI 10.1111/iej.70234, PMID 42581563) as a mature permanent tooth that did not respond to conventional chemomechanical disinfection because of persistent sanguopurulent exudate, which the authors interpret as evidence of an extraradicular infection.
What the clinicians did
After apical microsurgery to remove the extraradicular biofilm, the team compacted autologous concentrated growth factors (CGF) into both the pulp space and the surgical site and sealed the crown with iRoot BP Plus. The protocol combined a regenerative endodontic procedure with microsurgery, aiming to promote intracanal tissue repair and periapical bone healing at the same time. The work was supported by the Natural Science Foundation of Beijing Municipality.
What the 24-month readouts showed
The follow-up assessment used laser Doppler flowmetry (LDF), MRI, and cone beam computed tomography (CBCT). According to the abstract, complete periapical osseous healing was seen at 12 months. At 18 and 24 months, LDF showed blood perfusion in the treated tooth comparable to the contralateral healthy tooth, and MRI showed continuous homogeneous pulp-like signal inside the intraradicular tissue. Cold and electric pulp testing were positive from 6 months onward, which the authors attribute to recovery of sensory nerve fibre function rather than definitive pulp vitality. CBCT volumetric analysis recorded a 9.88% reduction in pulp space volume over 24 months, suggesting hard-tissue deposition, though the tissue was not histologically confirmed.
What it does and does not mean
This is a single case report, not a controlled study, so the outcome cannot be generalized to other teeth or patients. The positive pulp tests and MRI signal are encouraging, but they do not prove that true pulp-dentin complex regeneration occurred. The 9.88% reduction in pulp space volume indicates mineral deposition of some kind; without histology, it could be reparative dentin, cementum-like tissue, or a mixture. The authors explicitly frame the sensory responses as nerve fibre recovery rather than confirmed vitality.
Where it sits
For the pulp and dentine repair program, the case adds a human datapoint at the aggressive end of the repair spectrum: a mature permanent tooth with a blunderbuss apex and extraradicular infection, treated with a combined surgical and regenerative approach. It does not change the program tier, because it is one patient and the regenerative nature of the intracanal tissue is inferred rather than proven. The current field assessment remains at /field/.
Provenance: this analysis was grounded in the peer-reviewed PubMed/MEDLINE record (PMID 42581563) and the Crossref bibliographic record for the article, per our method at /method/.