Microbial Loads in Traumatized Immature Teeth and Their Impact on the Treatment Outcomes of Regenerative Endodontic Treatment: A Randomized Clinical Trial Comparing Chlorhexidine and Calcium Hydroxide

Alina Wikström; Olena Rakhimova; Pavel Călin; Georgios Tsilingaridis; Malin Brundin; Nelly Romani Vestman

doi:10.1111/edt.13062

Microbial Loads in Traumatized Immature Teeth and Their Impact on the Treatment Outcomes of Regenerative Endodontic Treatment: A Randomized Clinical Trial Comparing Chlorhexidine and Calcium Hydroxide

Dent Traumatol. 2025 Mar 27. doi: 10.1111/edt.13062. Online ahead of print.

Authors

Alina Wikström^{1

2

3}, Olena Rakhimova², Pavel Călin⁴, Georgios Tsilingaridis^{2

3}, Malin Brundin⁵, Nelly Romani Vestman⁵

Affiliations

¹ Department of Endodontics, Public Dental Health Services, Eastman Institute, Stockholm, Sweden.
² Division of Paediatric Dentistry, Department of Dental Medicine, Karolinska Institute, Stockholm, Sweden.
³ Centre of Paediatric Oral Health, Huddinge, Sweden.
⁴ Department of Odontology, "Nicolae Testemitanu" State University of Medicine and Pharmacy, Chisinau, Moldova.
⁵ Department of Odontology, Umeå University, Umeå, Sweden.

PMID: 40150951
DOI: 10.1111/edt.13062

Abstract

Introduction: Regenerative endodontic treatment (RET) aims to promote root maturation in necrotic immature teeth, where effective microbial disinfection is crucial for treatment success. This study evaluated the effect of calcium hydroxide (CH) and 2% chlorhexidine gluconate (CHD) as intracanal medicaments and their impact on bacterial loads and RET outcomes.

Methods: The material consisted of bacterial samples from 41 patients who participated in a previously conducted randomized controlled clinical trial comparing CH and CHD during RET. A total of 123 microbial samples were analyzed using real-time quantitative polymerase chain reaction (qPCR). Bacterial loads were assessed at three time points: before root canal disinfection (S1), after root canal disinfection (S2), and after intracanal dressing (S3). The microbial composition was evaluated at the kingdom (Eubacteria), phylum (Actinomycetota), and species (Enterococcus faecalis) levels.

Results: Significant reductions in bacterial loads were observed after root canal disinfection (S2) in both CH and CHD subgroups, regardless of treatment outcome. Further reductions after intracanal dressing (S3) occurred exclusively in the successful cases. Actinomycetota loads significantly decreased after root canal disinfection in the successful cases but remained unchanged after intracanal medication. The presence of E. faecalis after intracanal dressing was associated with failed RET (OR = 9.778; p = 0.0432), although no significant differences in the effectiveness of the intracanal medicaments were found.

Conclusion: Both CH and CHD effectively reduced bacterial loads, with greater reductions linked to successful outcomes. The association between E. faecalis and failed RET suggests that this species may play a role in treatment outcomes. Further research, including microbiome profiling, is desirable to identify potential prognostic markers for failed RET.

Keywords: antibacterial effectiveness of calcium hydroxide and 2% chlorhexidine; bacterial loads; immature traumatized teeth; quantitative polymerase chain reaction; regenerative endodontic treatment.

Abstract

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