What the study is
Gözde Kandemir Demirci and seven colleagues at Ege University in Izmir, Turkey, published a laboratory study in the Australian Endodontic Journal (52(2):470-479, online 13 March 2026, doi:10.1111/aej.70071; open access). It is written to the PRILE 2021 reporting guidelines for laboratory studies in endodontology and was approved by the Ege University ethics committee (decision 23-1.IT/37). The question is practical: if a patient has impacted third molars removed, a routine procedure in young adults, can the pulp stem cells inside be banked at a hospital freezer temperature and still be alive a year later, for a possible future regenerative endodontic procedure? The work was funded by the Aliye Üster Foundation; the authors declare no conflicts of interest.
What they did
The team isolated dental pulp stem cells (DPSCs) from 21 fully impacted third molars extracted from 15 patients aged 18 to 29, choosing unerupted teeth specifically to avoid bacterial contamination. All sampled molars were developmentally immature (Nolla root stages 2-3, apices not closed). Pulp was digested with collagenase type I (3 mg/mL, 45 minutes at 37°C) and cultured to about 80 percent confluence. Four teeth from three patients went to flow cytometry only; the other 17 teeth from 14 patients formed the viability cohort. Cells were frozen at roughly 1 million cells per vial in 90 percent fetal bovine serum with 10 percent DMSO and stored at -86°C, the temperature of an ultralow mechanical freezer rather than liquid nitrogen. One vial per case was thawed at 1, 3, 6, 9, and 12 months and viability was read by trypan blue with a hemocytometer.
What they measured
Two numbers anchor the protocol. First, 96 percent of the flow-cytometry-analyzed cells matched the mesenchymal stromal cell surface profile (CD90, CD73, CD105, and CD44 positive; CD11b, CD14, CD19, CD34, CD45, CD79a, and HLA-DR negative), which is the ISCT-style marker panel used to argue the isolates really are DPSCs. Second, the mean harvest concentration was 3.43 million cells per mL (range 1.5 to 6.88 million), from a single T-25 flask per tooth. The authors describe this as a standardized, therapeutic-grade isolation and storage protocol; it is standardized within this one study, from one center, at passage 0.
What a year in the freezer did
Mean post-thaw viability was 89.78 percent at month 1, 87.87 percent at month 3, 88.62 percent at month 6, 88.40 percent at month 9, and 88.74 percent at month 12; the case-level range at month 12 was 74 to 97 percent. Two statistical patterns matter. Viability dropped significantly from the pre-freeze baseline at every post-thaw point (pairwise p less than 0.0001), so freezing cost some cells up front. But there was no significant difference between month 1 and month 12 (p = 0.753 to 1.000), and an ANOVA on viability relative to each case’s own month-1 value found no significant change across months (p = 0.106). In plain terms: most of the loss happens at freezing and thawing, not during storage, at least to 12 months. Only 10 of the 17 cases had vials left for the 9- and 12-month thaws, so the long-term endpoint rests on a small sample.
Where the boundary sits
This is a viability study, nothing more. No thawed cells were differentiated, transplanted, or tested for pulp or dentin formation in this paper; the claim that they retain “biological potential” rests on marker expression and morphology, with cell sizes in the 80 to 170 micrometer range throughout. Storage at -86°C in an ultralow freezer is itself a choice worth noting, because most cell-banking practice targets liquid nitrogen temperatures, and 12 months is short for a bank that may need to hold cells for decades. The donors were all under 30 with immature molars, which is exactly the population with the youngest pulp but says nothing about cells from older patients. The authors’ statement that this is the only study to test 12-month cryopreservation of DPSCs from adult impacted third molars is plausible and we could not contradict it, but it is the authors’ own framing.
What it changes
For the pulp and dentine repair program, the study addresses a logistics gap rather than a biology gap. The strongest human result in this program, the Xuan et al. randomized trial of autologous pulp stem cell grafts in immature incisors, required a donor tooth and an implantation window in the same child; a bank of the patient’s own third-molar DPSCs is one way to decouple harvesting from treatment. This paper shows that decoupling is feasible at the first, easiest checkpoint, cell survival to one year. It does not show the banked cells still repair pulp, and the field assessment does not change on this record. No press coverage of this study exists as of 27 September 2026; if it is covered, the likely frame, that wisdom teeth can now be banked for future tooth regeneration, should be narrowed to what was measured: high one-year survival of characterized pulp stem cells in a freezer, in one center’s hands, with function untested.
Provenance: grounded in the full text of Kandemir Demirci, Germiyan, Şimşek, Kaval, Güneri, Tekin, Köse, and Uyanıkgil (2026), Australian Endodontic Journal 52(2):470-479, published online 13 March 2026, doi:10.1111/aej.70071, retrieved from PubMed Central (PMC13436255) on 27 September 2026; volume, issue, pages, and publication date confirmed against the Crossref record for the same DOI. See /method/.