Lokeshwaran Manoharan, Malin Brundin, Olena Rakhimova, Luis Chávez de Paz, Nelly Romani Vestman
4 min
Traumatic dental injuries in young individuals often lead to pulp necrosis, which can cause aberrant root formation if left untreated. Regenerative endodontic treatments (RETs) aim to restore root development, but their success depends heavily on effective disinfection of the pulpal space. This study sought to identify the microbial profiles of infected root canals in traumatized teeth and compare them to non-trauma-related infections. The researchers analyzed 62 cases (30 trauma, 32 non-trauma) using a combination of culture-based methods and high-throughput Illumina MiSeq sequencing of the 16S rRNA gene to characterize the bacterial communities.
The study revealed that traumatized teeth harbor a highly diverse microbial community. While both trauma and non-trauma groups shared common phyla such as Firmicutes, Bacteroidetes, and Fusobacteria, the specific microbial composition differed significantly between the two groups. Notably, several species associated with biofilm formation—specifically Eubacterium yurii (subspecies yurii and margaretiae), Fusobacterium nucleatum (subspecies polymorphum), and Corynebacterium matruchotti—were highly associated with traumatized teeth. These findings remained significant even when controlling for age and tooth position, suggesting that the unique micro-environment created by dental trauma selects for a distinct microbial profile.
Understanding the specific microbial landscape of traumatized teeth is essential for developing targeted antimicrobial protocols. Because current regenerative treatments like RET can be compromised by persistent bacteria, identifying these specific "bridging" or keystone species provides a roadmap for more effective disinfection strategies. This research highlights that trauma-induced infections are not identical to standard primary endodontic infections, necessitating tailored clinical approaches to improve long-term outcomes for young patients.
Traumatic dental injuries in young individuals are often exposed to the invasion of oral microorganisms that leads to pulp necrosis. Infective necrosis in permanent teeth not-fully-developed causes aberrant root formation. Regeneration endodontic treatments (RETs) have shown promising results by promoting continued root development by stem cells. Critical to the success of RET is the thorough disinfection of the pulpal space. To establish effective antimicrobial protocols for root canal disinfection, the invading microorganisms need to be identified. In the present study, we use a combination of culture-based and high-throughput molecular sequencing techniques to investigate the microbial profiles from traumatized teeth (30 cases) and controls, i.e., teeth with pulp infections not caused by trauma (32 cases). Overall, a high microbial diversity in traumatized necrotic teeth was observed. Eubacterium yurii subsps. yurii and margaretiae, as well as key 'bridging oral species' F. nucleatum sp., Polymorphum and Corynebacterium matruchotti, were highly associated with traumatized teeth. The microbial compositions of traumatized teeth differed considerably from those of infected teeth not caused by trauma. Age and tooth position also influence microbial compositions. In conclusion, we show that the root canal microflora of traumatized teeth is highly diverse, and it differs from root canal infections not caused by trauma.
Alex: [nodding] That's where the clinical implication gets sharp. Regenerative endodontic procedures depend on creating a sterile — or near-sterile — scaffold environment that stem cells from the apical papilla can populate. If you leave behind the structural architects of a resilient biofilm, you're not just risking reinfection in the abstract. You're creating conditions that are actively hostile to the cell types the treatment depends on. The paper doesn't report outcome data directly, but the mechanistic inference is hard to avoid.
Sam: [analytical] And that's a limitation worth naming. The study characterizes the microbial community — it doesn't follow patients through treatment to show that the presence of these bridging species actually predicts failure. That's the next experiment.
Alex: [measured] Fair point. What the paper establishes is the ecological fingerprint. The clinical translation — whether targeting Fusobacterium nucleatum or its functional equivalents changes regenerative outcomes — that's still an open question. But the characterization itself is the necessary first step. You can't design a targeted protocol without knowing what you're targeting. [[RP_SECTION:future-research-and-treatment|Future research and treatment]]
Sam: [reflective] It's a useful reframe. The instinct in endodontics is to treat necrotic pulp as a category — same irrigants, same concentrations, same sequence. But if the etiology shapes the community structure in a meaningful way, then trauma cases may need a protocol that's specifically calibrated to disrupt biofilm architecture, not just reduce bacterial counts.
Alex: [calm, concluding] That's the broader point the paper is making. The ecological history of the tooth — how it became necrotic, not just that it is necrotic — appears to be a clinically relevant variable. Whether that eventually translates into etiology-stratified treatment guidelines is an empirical question, but this kind of high-resolution community profiling is what makes it answerable. Thanks for listening to ResearchPod.