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Aim: To compare differences in the disinfection efficacy of calcium hydroxide (CH) and chlorhexidine gluconate (CHD) dressings in pulp revitalization (PR) of traumatized immature necrotic teeth; to investigate the microflora in successful/failed PR and whether bacterial persistence influences the outcomes of PR.

Methods: Microbiological assessment of the average bacterial load (CFU/sample) and bacterial diversity (taxa/sample) was performed on 41 teeth at three timepoints (S2-before, S3-after debridement and S5- after root canal dressing).

Results: The primary microflora was more diverse in successful cases than in failed. Decreases in CFU/sample and taxa/sample occurred S2 - S3, though new increases occurred at S5 in the CHD subgroup (successful and failed) and CFU/sample in the CH subgroup (failed). At S5, the successful cases showed more bacterial decreases. No specific species was associated with the outcomes with no statistical differences between the disinfection efficacy.

Conclusions: There were no statistical differences in CH and CHD efficacy. At S5, microflora persisted in both successful and failed outcomes, but the abundance and diversity increased significantly only in the failed cases. The successful outcomes presented higher diversity and higher decreases of the primary microflora at S5 than the failed outcomes. The abundance and diversity increased significantly at S5 only in failed cases.

Background/Aim: To evaluate the long-term survival of immature traumatized incisors with pulp necrosis and apical periodontitis after endodontic treatment with two apexification techniques (calcium hydroxide apexification and MTA-apical plug) and to identify major factors affecting the survival of these teeth.

Materials and Methods: Records of 2400 children and adolescents were screened for presence of traumatic dental injuries to immature incisors where endodontic treatment with the two apexification techniques was performed during January 2003 and December 2022, compared to a control group of mature teeth treated with conventional endodontic techniques. The studied variables were age; sex; apexification technique, presence of luxation and hard tissue injuries; preoperative root development stage (RDS), preoperative and postoperative periapical index (PAI), the time-point for tooth loss, and overall survival time in years. Kaplan–Meier estimates were used to graphically present the survival functions and Cox proportional hazard model to calculate hazard ratios (HR, 95% CI).

Results: The median survival time was 10 years for calcium hydroxide apexification, 16.1 for MTA-apexification, for luxation injuries other than intrusions and avulsions 15.5 years, for intrusions 12.5 years and for avulsions 6.8 years. The variables with significant negative impact on tooth survival were calcium hydroxide apexification, avulsion and postoperative PAI 3–5. No significant relationships were found for the variables MTA apexification, concussion; subluxation; lateral luxation; extrusion, intrusion, hard tissue injuries, preoperative RDS and PAI scores and postoperative PAI 1–2. After adjustment, the risk for premature tooth loss was 13.5 times higher in calcium hydroxide apexification, approximately 2 to 4 times higher in PAI 3–5, and 5.6 times higher in avulsions.

Conclusions: Calcium hydroxide apexification, avulsion, and postoperative PAI 3–5 were identified as prognostic variables with significant negative impact on the risk for premature tooth loss.

Enterococcus faecalis, a leading multi-resistant nosocomial pathogen, is also the most frequently retrieved species from persistently infected dental root canals, suggesting that the oral cavity is a possible reservoir for resistant strains. However, antimicrobial susceptibility testing (AST) for oral enterococci remains scarce. Here, we examined the AST profiles of 37 E. faecalis strains, including thirty-four endodontic isolates, two vanA-type vancomycin-resistant isolates, and the reference strain ATCC-29212. Using Etest gradient strips and established EUCAST standards, we determined minimum inhibitory concentrations (MICs) for amoxicillin, vancomycin, clindamycin, tigecycline, linezolid, and daptomycin. Results revealed that most endodontic isolates were susceptible to amoxicillin and vancomycin, with varying levels of intrinsic resistance to clindamycin. Isolates exceeding the clindamycin MIC of the ATCC-29212 strain were further tested against last-resort antibiotics, with 7/27 exhibiting MICs matching the susceptibility breakpoint for tigecycline, and 1/27 reaching that of linezolid. Both vanA isolates confirmed vancomycin resistance and demonstrated resistance to tigecycline. In conclusion, while most endodontic isolates remained susceptible to first-line antibiotics, several displayed marked intrinsic clindamycin resistance, and MICs matched tigecycline’s breakpoint. The discovery of tigecycline resistance in vanA isolates highlights the propensity of clinical clone clusters to acquire multidrug resistance. Our results emphasize the importance of implementing AST strategies in dental practices for continued resistance surveillance.

Introduction: This study's aim was to calculate the incidence of first additional endodontic treatment or extraction as the result of an unfavorable endodontic outcome following orthograde root canal treatment (RCT) performed by general dental practitioners during a 10-year period and to identify possible predictors for outcomes.

Methods: A randomized cohort of 280 individuals (and as many teeth) with an orthograde RCT was followed for over 10 years. Dental records were reviewed, and individuals were recalled when data were missing. The following terminal events indicative of unfavorable endodontic treatment outcome were orthograde retreatment, surgical endodontics, and tooth extractions exclusively due to endodontic reasons. Selected variables related to individuals and treatment (pre-, intra-, and postoperative) were harvested to analyze possible associations with the terminal events. Unadjusted survival analysis and Cox regression analysis were performed and P < .05 was considered statistically significant.

Results: Terminal events were registered for 22 teeth/individuals and 17 of these were orthograde retreatments. The cumulative 10-year survival of RCTs was 92.7% (standard error 1.7%), with a higher yearly incidence during the first 2 years. The univariate analysis identified 5 factors associated with the outcome. There were too few events to perform a multivariate analysis.

Conclusions: The mean incidence of additional treatment indicative of unfavorable endodontic outcome was 0.7% per year during the first 10 years, but the mean incidence was greater during the first 2 years. Five factors were associated with an unfavorable outcome; however, confounders cannot be excluded from the associations.

Objective: The aim was to evaluate the establishment of an aseptic endodontic operative field in general dentistry by assessing general dentists’ ability to reduce the amount of contamination to a non-cultivable level, and to compare the operative field asepsis at a general dentistry clinic with that at an endodontic specialist clinic.

Materials and Methods: A total of 353 teeth were included in the study (153 in general dentistry, 200 at the specialist clinic). After isolation, control samples were taken, the operative fields disinfected with 30% hydrogen peroxide (1 min) followed by 5% iodine tincture or.5% chlorhexidine solution. Samples were collected from the access cavity area and buccal area, placed in a fluid thioglycolate medium, incubated (37°, 7 d), evaluated for growth/non-growth.

Results: Significantly more contamination was observed at the general dentistry clinic (31.6%, 95/301), than at the endodontic specialist clinic (7.0%, 27/386) (p <.001). In general dentistry, significantly more positive samples were collected in the buccal area than in the occlusal area. Significantly more positive samples were collected when the chlorhexidine protocol had been used, both in general dentistry (p <.001) and at the specialist clinic (p =.028).

Conclusions: The result from this study shows insufficient endodontic aseptic control in general dentistry. At the specialist clinic, both disinfection protocols were able to reduce the amount of microorganisms to a non-cultivable level. The observed difference between the protocols may not reflect a true difference in the effectiveness of the antimicrobial solutions, as confounding factors may have contributed to the result.

Introduction: Bacterial persistence is considered one of the main causal factors for regenerative endodontic treatment (RET) failure in immature permanent teeth. This interference is claimed to be caused by the interaction of bacteria that reside in the root canal with the stem cells that are one of the essentials for RET. The aim of the study was to investigate whether prolonged exposure of stem cells from the apical papilla (SCAP) to bacterial remnants of Fusobacterium nucleatum, Actinomyces gerensceriae, Slackia exigua, Enterococcus faecalis, Peptostreptococcaceae yurii, commonly found in infected traumatized root canals, and the probiotic bacteria Lactobacillus gasseri and Limosilactobacillus reuteri, can alter SCAP’s inflammatory response and mineralization potential.

Methods: To assess the effect of bacterial remnants on SCAP, we used UV-C–inactivated bacteria (as cell wall-associated virulence factors) and bacterial DNA. Histochemical staining using Osteoimage Mineralization Assay and Alizarin Red analysis was performed to study SCAP mineralization, while inflammatory and osteo/odontogenic-related responses of SCAPs were assessed with Multiplex ELISA.

Results: We showed that mineralization promotion was greater with UV C–inactivated bacteria compared to bacterial DNA. Immunofluorescence analysis detected that the early mineralization marker alkaline phosphatase (ALP) was increased by the level of E. coli lipopolysaccharide (LPS) positive control in the case of UV-C–inactivated bacteria; meanwhile, DNA treatment decreased the level of ALP compared to the positive control. SCAP’s secretome assessed with Multiplex ELISA showed the upregulation of pro-inflammatory factors IL-6, IL-8, GM-CSF, IL-1b, neurotrophic factor BDNF, and angiogenic factor VEGF, induced by UV-C–killed bacteria.

Discussion: The results suggest that long term stimulation (for 21 days) of SCAP with UV-C–inactivated bacteria stimulate their mineralization and inflammatory response, while DNA influence has no such effect, which opens up new ideas about the nature of RET failure.

Acyl-homoserine lactones (AHLs) are typical quorum-sensing molecules of gram-negative bacteria. Recent evidence suggests that AHLs may also affect gram-positives, although knowledge of these interactions remains scarce. Here, we assessed the effect of AHLs on biofilm formation and transcriptional regulations in the gram-positive Enterococcus faecalis. Five E. faecalis strains were investigated herein. Crystal violet was employed to quantify the biomass formed, and confocal microscopy in combination with SYTO9/PI allowed the visualisation of biofilms’ structure. The differential expression of 10 genes involved in quorum-sensing, biofilm formation and stress responses was evaluated using reverse-transcription-qPCR. The AHL exposure significantly increased biofilm production in strain ATCC 29212 and two isolates from infected dental roots, UmID4 and UmID5. In strains ATCC 29212 and UmID7, AHLs up-regulated the quorum-sensing genes (fsrC, cylA), the adhesins ace, efaA and asa1, together with the glycosyltransferase epaQ. In strain UmID7, AHL exposure additionally up-regulated two membrane-stress response genes (σV, groEL) associated with increased stress-tolerance and virulence. Altogether, our results demonstrate that AHLs promote biofilm formation and up-regulate a transcriptional network involved in virulence and stress tolerance in several E. faecalis strains. These data provide yet-unreported insights into E. faecalis biofilm responses to AHLs, a family of molecules long-considered the monopole of gram-negative signalling.

Background. Complications of orthognathic surgery are quite rare, but they cause suffering in affected individuals.The range of complications is broad and includes both hard and soft tissue.

Case presentation: We here present a case of a fully healthy woman without signs of impaired healing capacity. Thepatient underwent bimaxillary orthognathic surgery and experienced multiple complications both peri- and postoperatively.During the post operative period, the patient also suffered from soft tissue complications after an orthopaedicinjury. Therefore, we referred the patient to her general practitioner for further medical investigation. Wealso present the result after restorative surgery and endodontic and prosthodontic treatment resulting in a successfulrehabilitation.

Conclusion: This case report clearly shows the need for a good collaboration between different odontologicaland medical fields to achieve a good and predictable result. In situations where normal healing processesdo not occur, in-depth analysis must be carried out.

Highlights: Orthognathic surgery affects soft and hard tissue which can result in adverse healing and complications.It is of great importance to follow up performed surgery to see late complications. Be restrictive with earlyre-operations when there are signs of necrosis. Always use a multidisciplinary approach when handling complicationsafter surgery.

Aim: This prospective cohort study evaluates clinical and radiographical outcomes of endodontic pulp revitalization (PR) of traumatized necrotic incisors.

Methodology: Pulp revitalization was performed in 75 traumatized necrotic immature incisors from 71 patients. The radiographic outcome measures were continued root formation (width and length), root resorption, apex closure, periapical index, and root development stage. The clinical outcome measures were percussion pain, palpation pain, pathological tooth mobility, swelling, sinus tract, ankylosis, crown discolouration, response to pulp sensitivity test, and subjective pain. Treatment outcomes were categorized as a success based on the absence of clinical symptoms and when radiographic evidence was present for apical healing and continued root development. The performed statistical tests were repeated measures anova, pairwise comparisons of interactions (t-test), McNemar's test, and linear regression model.

Results: In 45 of 75 teeth (60%), PR was successful with the resolution of clinical and radiographic signs and continued root development. PR failed due to the absence of bleeding (n = 19) and persistent infection (n = 11). PR showed statistically significant increases in root length (11%), and dentinal wall thickness (30%), root maturation (pre-operative 3.38 [CI 1.88; 4.88]; post-operative 4.04, [CI 2.56; 5.52]) apical closure (71.4%), healing of pre-operative apical periodontitis (100%), and healing of pre-operative inflammatory root resorptions (100%). Three predictive variables for continued root maturation were identified – root development stage at entry (p =.0001, β 0.649), [CI 0.431; 0.867], trauma to the soft tissues (p =.026, β −0.012), [CI −0.0225; −0.015], and pre-operative dentinal wall thickness (p =.009, β −0.001); [CI −0.001; 0.0001].

Conclusions: Our findings indicate that PR provides satisfactory clinical and radiographical outcomes in traumatized necrotic incisors. The failed cases were related to lack of bleeding and persistent infections, indicating that new techniques are needed to improve the predictability of PR.

Knowledge of photo-oxidative stress responses in bacteria that survive antimicrobial photodynamic therapy (aPDT) is scarce. Whereas aPDT is attracting growing clinical interest, subsequent stress responses are crucial to evaluate as they may lead to the up-regulation of pathogenic traits. Here, we aimed to assess transcriptional responses to sublethal aPDT-stress and identify potential connections with virulence-related genes. Six Enterococcus faecalis strains were investigated; ATCC 29212, three dental root-canal isolates labelled UmID1, UmID2 and UmID3 and two vancomycin-resistant isolates labelled A1 and A2. TMPyP was employed as a photosensitiser. A viability dose-response curve to increasing concentrations of TMPyP was determined by culture plating. Differential expression of genes involved in oxidative stress responses (dps and hypR), general stress responses (dnaK, sigma-factorV and relA), virulence-related genes (ace, fsrC and gelE) and vancomycin-resistance (vanA) was assessed by reverse-transcription qPCR. TMPyP-mediated aPDT inactivated all strains with comparable efficiencies. TMPyP at 0.015 μM was selected to induce sublethal photo-oxidative stress. Despite heterogeneities in gene expression between strains, transcriptional profiles revealed up-regulations of transcripts dps, hypR as well as dnaK and sigma factorV after exposure to TMPyP alone and to light-irradiated TMPyP. Specifically, the alternative sigma factorV reached up to 39 ± 113-fold (median ± IQR) (p = 0.0369) in strain A2. Up-regulation of the quorum sensing operon, fsr, and its downstream virulence-related gelatinase gelE were also observed in strains ATCC-29212, A1, A2 and UmID3. Finally, photo-oxidative stress induced vanA-type vancomycin-resistance gene in both carrier isolates, reaching up to 3.3 ± 17-fold in strain A2 (p = 0.015). These findings indicate that, while aPDT successfully inactivates vancomycin-resistant and naïve strains of E. faecalis, subpopulations of surviving cells respond by co-ordinately up-regulating a network of genes involved in stress survival and virulence. This includes the induction of vancomycin-resistance genes in carrier isolates. These data may provide the mechanistic basis to circumvent bacterial responses and improve future clinical protocols.