Effect of Probiotic Supplements on the Oral Microbiota-A Narrative Review.

Data from systematic reviews and meta-analyses show that probiotics positively impact clinical parameters of oral diseases such as gingivitis, dental caries, and periodontitis. However, the working mechanism of probiotics is not fully understood, but is hypothesized to be mediated by direct and indirect interactions with the oral microbiota and the human host. In the present narrative review, we focused on the microbiological effect of probiotic supplements based on data retrieved from randomized clinical trials (RCTs). In addition, we assessed to what extent contemporary molecular methods have been employed in clinical trials in the field of oral probiotics. Multiple RCTs have been performed studying the potential effect of probiotics on gingivitis, dental caries, and periodontitis, as evaluated by microbial endpoints. In general, results are conflicting, with some studies reporting a positive effect, whereas others are not able to record any effect. Major differences in terms of study designs and sample size, as well as delivery route, frequency, and duration of probiotic consumption, hamper comparison across studies. In addition, most RCTs have been performed with a limited sample size using relatively simple methods for microbial identification, such as culturing, qPCR, and DNA-DNA checkerboard, while high-throughput methods such as 16S sequencing have only been employed in a few studies. Currently, state-of-the-art molecular methods such as metagenomics, metatranscriptomics, and metaproteomics have not yet been used in RCTs in the field of probiotics. The present narrative review revealed that the effect of probiotic supplements on the oral microbiota remains largely uncovered. One important reason is that most RCTs are performed without studying the microbiological effect. To facilitate future systematic reviews and meta-analyses, an internationally agreed core outcome set for the reporting of microbial endpoints in clinical trials would be desirable. Such a standardized collection of outcomes would most likely improve the quality of probiotic research in the oral context.

Characterization of patients with odontogenic necrotizing soft tissue infections in the head and neck area. A retrospective analysis.

OBJECTIVE: Necrotizing soft-tissue infection (NSTI) in the head and neck area may develop from odontogenic infections. The aim of this study was to characterize patients with NSTI in the head and neck with odontogenic origin in a well-defined prospectively collected cohort. MATERIAL AND METHODS: Patients with NSTI in the head and neck, hospitalized between 2013 and 2017 at Copenhagen University Hospital and registered in the Scandinavian INFECT database were included. Medical records of identified patients and from the INFECT database were screened for a defined set of data including the primary focus of infection, comorbidities, predisposing factors, clinical and radiographic diagnostics, course of treatment, and treatment outcome. RESULTS: Thirty-five patients with NSTI in the head and neck area were included in the study. A total of 54% had odontogenic origin, primarily from mandibular molars, and 94% had radiographic signs of infectious oral conditions. Overall, comorbidities were reported in 51% with cardiovascular disease being the most prevalent. In 20%, no comorbidities or predisposing conditions could be identified. The overall 30-day mortality rate was 9%. CONCLUSIONS: More than half of NSTI cases in the head and neck region had an odontogenic origin, and special attention should be paid to infections related to mandibular molars.

Probiotics Support Resilience of the Oral Microbiota during Resolution after Experimental Gingivitis-A Randomized, Double-Blinded, Placebo-Controlled Trial.

The present study aims to test whether probiotics protect against experimental gingivitis incited by 14 days of oral hygiene neglect and/or subsequently support the restoration of oral homeostasis. Eighty systemically and orally healthy participants refrained from oral hygiene procedures for 14 days, followed by 14 days with regular oral hygiene procedures. Additionally, participants consumed either probiotics (n = 40) or placebo (n = 40) throughout the trial. At baseline, day 14, and day 28, supragingival plaque score and bleeding-on-probing percentage (BOP %) were registered, and supragingival plaque and saliva samples were collected. The supragingival microbiota was characterized using 16S sequencing, and saliva samples were analyzed for levels of pro-inflammatory cytokines and proteases. At day 28, the relative abundance of Lautropia (p = 0.014), Prevotella (p = 0.046), Fusobacterium (p = 0.033), and Selenomonas (p = 0.0078) genera were significantly higher in the placebo group compared to the probiotics group, while the relative abundance of Rothia (p = 0.047) species was associated with the probiotics group. Streptococcus sanguinis was associated with the probiotics group, while Campylobacter gracilis was associated with the placebo group. No difference was observed in salivary cytokines, albumin, or any enzyme activity. The present study suggests that probiotics support the resilience of the oral microbiota in the resolution period after gingivitis.

Probiotics Partly Suppress the Impact of Sugar Stress on the Oral Microbiota-A Randomized, Double-Blinded, Placebo-Controlled Trial.

The aim was to test if probiotics counteract oral dysbiosis during 14 days of sugar stress and subsequently help restore oral homeostasis. Eighty healthy individuals received either probiotics (n = 40) or placebo lozenges (n = 40) for 28 days and rinsed with a 10% sucrose solution 6-8 times during the initial 14 days of the trial. Saliva and supragingival samples were collected at baseline, day 14, and day 28. Saliva samples were analyzed for levels of pro-inflammatory cytokines, albumin, and salivary enzyme activity. The supragingival microbiota was characterized according to the Human Oral Microbiome Database. After 14 days of sugar stress, the relative abundance of Porphyromonas species was significantly higher (p = 0.03) and remained significantly elevated at day 28 in the probiotic group compared to the placebo group (p = 0.004). At day 28, the relative abundance of Kingella species was significantly higher in the probiotic group (p = 0.03). Streptococcus gordinii and Neisseria elongata were associated with the probiotic group on day 28, while Streptococcus sobrinus was associated with the placebo group on day 14 and day 28. On day 28, the salivary albumin level was significantly lower in the probiotic group. The present study demonstrates a potential stabilizing effect on the supragingival microbiota mediated by consumption of probiotics during short-term sugar stress.

The efficacy of combined arginine and probiotics as an add-on to 1450 ppm fluoride toothpaste to prevent and control dental caries in children - A randomized controlled trial.

OBJECTIVES: To determine how daily consumption of a lozenge combining arginine and two probiotic strains affects the Relative Risk Reduction (RRR) in children regarding dental caries transitions and lesion activity at tooth surface level during 10-12 months. METHODS: A total of 21,888 tooth surfaces in 288 children were examined. The intervention group (n = 141) received a lozenge containing 2% arginine, Lacticaseibacillus rhamnosus, LGG® (DSM33156), and Lactobacillus paracasei subsp. paracasei, L. CASEI 431® (DSM33451). The placebo group (n = 147) received a placebo lozenge. Both groups received 1,450 ppm F- toothpaste. Primary canines, molars, and first permanent molars were examined clinically (ICDAS0-6) and radiographically (R0-6) at baseline and follow-up. Sealed, filled, and missing surfaces were also included. Caries activity was computed as a sum of each caries lesion's location, color, texture, cavitation, and gingival bleeding. RRRs were computed with cluster effect on surface level. ICH-GCP was followed, including external monitoring. RESULTS: A total of 19,950 surfaces were analyzed after excluding 1,938 tooth surfaces. No statistically significant differences were found between the groups. The RRRs showed less caries progression (13.6%, p = 0.20), more regression (0.3%, p = 0.44), and fewer active caries lesions (15.3%, p = 0.15) in the intervention group. CONCLUSION: Daily consumption of a lozenge combining arginine and probiotics for 10-12 months given to 5-9-years-old children characterized being with low caries risk demonstrated a marked, though not statistically significant RRR for caries progression, regression, and number of active lesions in the intervention group compared to the placebo-group. CLINICALTRIALS: gov (NCT03928587). CLINICAL SIGNIFICANCE: Since all the RRRs were in favor of the intervention group and the PF of combined arginine and probiotics is high (81.6%) compared to fluoride toothpaste (24.9%) and arginine-fluoride toothpaste alone (19.6%) the combined pre-and probiotics approach may be a future additional tool regarding caries prevention and control.

The national child odontology registry (SCOR): a valuable resource for odontological and public health research.

BACKGROUND: Since 1972 The National Child Odontology Registry has collected data on the oral health of most of all Danish children and adolescents. However, comprehensive information on the registry has not previously been available, making it difficult to approach and use the registry for research purposes. METHODS: By combining historical documentation and simple descriptive statistics we provide an overview of major events in the timeline of The National Child Odontology Registry and discuss how they impact the available data. We provide a broad overview of the dental variables in the registry, and how the registration criteria for some of the core dental variables (gingivitis, periodontitis, and dental caries) have changed over time. We then provide examples of how aggregate variables for the core dental diseases, allowing for comparison across registration criteria, can be created. RESULTS: Most of the Danish population born during or after 1965 have a least one entry in the National Child Odontology Registry, with 68% having entries spanning their entire childhood and adolescence. The prevalence of gingivitis and periodontitis seem to increase significantly in the years immediately following changes in how registration criteria for these variables, raising questions as to whether these diseases are generally underreported, or subject to overreporting in the years following the registration changes. The mandatory ages of registration instituted in 2003, do not appear to have had a strong impact on the ages at which registrations are made. For variables not directly comparable across datasets due to changes in registration criteria aggregate variables of measurements can be computed in most cases. CONCLUSIONS: The National Child Odontology Registry provides a unique opportunity to study the impact of childhood oral health on life trajectories, but using the registry is not without issues, and we strongly recommend consulting with experts in the field of odontology to ensure the best use of available data.

The effect of a lozenge combining prebiotic arginine and probiotics on caries increment in children during 10-12 months, a randomized clinical trial.

OBJECTIVES: To investigate the effect of daily use of a lozenge containing arginine and probiotics for 10-12 months on caries increment, gingivitis- and plaque occurrence in children aged 5-9 years. METHODS: In this placebo-controlled, double-blinded, parallel-grouped randomized clinical trial, 343 children were randomly assigned to one of the study arms (1:1). The intervention group (n = 172) received a lozenge containing Lacticaseibacillus rhamnosus, LGG® (DSM33156), Lactobacillus paracasei subsp. paracasei, L. CASEI 431® (DSM33451) and prebiotic (arginine 2%). The placebo group (n = 171) received an identical lozenge without arginine or probiotics. Primary canines and molars, and permanent first molars were examined clinically (d/D= ICDAS1-6) and radiographically (d/D = R1-6) at baseline and follow-up. Missing (m/M), sealed (s/S), and filled (f/F) surfaces (-s/-S) in both dentitions were also included. Utilizing clinical and radiographic scorings, caries experience was classified as dICDAS1-6msf-s (primary teeth), DICDAS1-6MSF-S (permanent teeth), d/DICDAS1-6 m/M-s/S-f/F-s/S (mixed dentition). A weighted and an unweighted score system was applied. RESULTS: The study was completed by 288 children. The dropout rate was 15%. The increase in ∆mean dICDAS3-6msf-s and ∆mean d/DICDAS3-6m/M-s/S-f/F-s/S was lower in the intervention group (p = 0.007). No differences were found for gingivitis- and plaque occurrence. No product-related side effects were reported. This study followed ICH-GCP including external monitoring. CONCLUSION: Daily consumption of a lozenge containing prebiotic arginine and two strains of probiotics showed safe use and statistically significantly reduction in caries incrementbut no effect on the mean plaque or gingivitis occurrence in children. The use of a lozenge with arginine and probiotics combined has a promising potential as a supplementary tool for future management of caries. www. CLINICALTRIALS: gov (NCT03928587). CLINICAL SIGNIFICANCE: The combination of prebiotic arginine and probiotics shows clinical potential as a supplementary approach to toothbrushing with fluoride toothpaste in managing caries increment in children. A new era in the management of caries may be emerging.

Short-term sugar stress induces compositional changes and loss of diversity of the supragingival microbiota.

Frequent intake of free sugars is a major risk factor for dental caries, but the immediate influence of sugar intake on the supragingival microbiota remains unknown. We aim to characterize the effect of 14 days of sugar rinsing on the supragingival microbiota. Forty orally and systemically healthy participants rinsed their mouth with a 10% sucrose solution, 6-8 times a day, for 14 days, followed by 14 days without sugar stress. Supragingival plaque samples were collected at baseline, and after 14, and 28 days. The supragingival microbiota was analyzed using 16S rDNA sequencing. Taxonomic classification was performed using the Human Oral Microbiome Database. After 14 days of sugar stress induced by the daily sugar rinses, a significant loss of α-diversity (p = 0.02) and a significant increase in the relative abundance of Actinomyces (6.5% to 9.6%, p = 0.006) and Corynebacterium (6.2% to 9.1%, p = 0.03) species were recorded. In addition, a significant decrease in Streptococcus (10.3% to 6.1%, p = 0.001) species was observed. Sugar-mediated changes returned to baseline conditions 14 days after the last sugar rinse. The present study shows that temporary sugar stress induces loss of diversity and compositional changes to the supragingival microbiota, which are reversible if oral care is maintained.

Cerebral abscesses with odontogenic origin: a population-based cohort study.

OBJECTIVES: Recent studies have indicated that cerebral abscess (CA) patients with odontogenic origin are on the rise. However, CA patients are often poorly characterized and with an unknown etiologic background. The purpose of this study is to identify and characterize CA patients that may have an odontogenic origin based on microbiologic, radiographic, and/or clinical findings. MATERIALS AND METHODS: This is a population-based cohort study analyzing retrospective and prospective data from CA patients. Radiographic examinations of panoramic radiographs (PRs) or computed tomography (CT) scans were conducted. CA patients characterized with odontogenic origin required the fulfilment of the following criteria on admission: (1) Oral pathologic conditions were the only bacterial infections present, (2) oral microorganisms were isolated in the purulent exudate from the brain, and (3) radiographically and/or clinical recordings of oral pathologic conditions. RESULTS: A total of 44 patients could be included in this study of which 25 (57%) were characterized as having CA with a likely odontogenic origin. Type two diabetes (T2D) (p = 0.014) and microorganisms of the Streptococcus anginosus group (SAG) (p < 0.01) were overrepresented in patients with CAs of odontogenic origin. CONCLUSIONS: Odontogenic infections may cause CAs to a greater extent than previously assumed. T2D was overrepresented among patients with odontogenic CA. When microorganisms of the SAG were isolated from the brain pus, CA patients had a predisposing odontogenic or sinus infection. CLINICAL RELEVANCE: The identification of patients with a likely odontogenic CA will contribute to understanding the etiology of the infectious disease and highlighting the importance of preserving oral health.

Effect of Different Concentrations of Sodium Hypochlorite on the Compressive Strength of Endodontically Treated Roots.

INTRODUCTION: The aim was to compare the compressive strength of dentin after irrigation with different concentrations of sodium hypochlorite (NaOCl). METHODS: A total of 259 extracted human tooth roots with no root caries or previous endodontic treatment were collected. They were sorted by size and length, and assigned to 7 groups (n = 37): negative control (no instrumentation, no irrigant), positive control (saline irrigant), 1%, 2.5%, 4%, 5.25%, and 10% NaOCl. A total of 13 mL NaOCl or saline (in 1-mL increments) was used per canal while being instrumented to #35 files (approximately 13 minutes). EDTAC (15%) was then used to remove the smear layer (2 minutes), followed by NaOCl as a final rinse. The roots were sectioned into 2-mm-thick disks and subjected to compression testing. RESULTS: There was a significant difference between the negative control group and all instrumented groups (P < .05). The positive control group was significantly different from the 5.25% group (P < .05) and had a low P value when compared with the 2.5% group and the other higher concentrations (P â‰… .1). When the NaOCl groups were compared with each other, there was a significant difference between 1% NaOCl and all higher concentrations (P < .05), but no significant difference when 2.5% NaOCl was compared with higher concentrations. CONCLUSION: A concentration of 1% NaOCl had the least effect on the compressive strength of dentin and this was significantly different from all higher concentrations tested. Therefore, the use of concentrations of NaOCl above 1% should be reconsidered.

Transcriptional Activity of Predominant Streptococcus Species at Multiple Oral Sites Associate With Periodontal Status.

Background: Streptococcus species are predominant members of the oral microbiota in both health and diseased conditions. The purpose of the present study was to explore if different ecological characteristics, such as oxygen availability and presence of periodontitis, associates with transcriptional activity of predominant members of genus Streptococcus. We tested the hypothesis that genetically closely related Streptococcus species express different transcriptional activities in samples collected from environments with critically different ecological conditions determined by site and inflammatory status. Methods: Metagenomic and metatranscriptomic data was retrieved from 66 oral samples, subgingival plaque (n=22), tongue scrapings (n=22) and stimulated saliva (n=22) collected from patients with periodontitis (n=11) and orally healthy individuals (n=11). Species-specific transcriptional activity was computed as Log2(RNA/DNA), and transcriptional activity of predominant Streptococcus species was compared between multiple samples collected from different sites in the same individual, and between individuals with different oral health status. Results: The predominant Streptococcus species were identified with a site-specific colonization pattern of the tongue and the subgingival plaque. A total of 11, 4 and 2 pathways expressed by S. parasanguinis, S. infantis and S. salivarius, respectively, were recorded with significantly higher transcriptional activity in saliva than in tongue biofilm in healthy individuals. In addition, 18 pathways, including pathways involved in synthesis of peptidoglycan, amino acid biosynthesis, glycolysis and purine nucleotide biosynthesis expressed by S. parasanguinis and 3 pathways expressed by S. salivarius were identified with significantly less transcriptional activity in patients with periodontitis. Conclusion: Data from the present study significantly demonstrates the association of site-specific ecological conditions and presence of periodontitis with transcriptional activity of the predominant Streptococcus species of the oral microbiota. In particular, pathways expressed by S. parasanguinis being involved in peptidoglycan, amino acid biosynthesis, glycolysis, and purine nucleotide biosynthesis were identified to be significantly associated with oral site and/or inflammation status.

Shotgun sequencing of clinical biofilm following scanning electron microscopy identifies bacterial community composition.

Bacterial biofilm infections often involve aggregates of bacteria heterogeneously distributed throughout a tissue or on a surface (such as an implanted medical device). Identification of a biofilm infection requires direct visualization via microscopy, followed by characterization of the microbial community by culturing or sequencing-based approaches. A sample, therefore, must be divided prior to analysis, often leading to inconsistent results. We demonstrate a combined approach, using scanning electron microscopy and next-generation shotgun sequencing, to visually identify a biofilm and characterize the microbial community, without dividing the sample. A clinical sample recovered from a patient following a dental root-filling procedure was prepared and visualized by scanning electron microscopy. DNA was then extracted from the sample several years later and analyzed by shotgun sequencing. The method was subsequently validated on in vitro cultures of Pseudomonas aeruginosa biofilm. Between 19 and 21 different genera and species were identified in the clinical sample with an estimated relative abundance greater than 1% by two different estimation approaches. Only eight genera identified were not associated with endodontic infections. This provides a proof-of-concept for a dual, microscopy and sequencing-based approach to identify and characterize bacterial biofilms, which could also easily be implemented in other scientific fields.

UV light assisted antibiotics for eradication of in vitro biofilms.

The overuse of antibiotics is accelerating the bacterial resistance, and therefore there is a need to reduce the amount of antibiotics used for treatment. Here, we demonstrate in vitro that specific wavelengths in a narrow range around 296 nm are able to eradicate bacteria in the biofilm state (grown for 24 hours) more effectively, than antibiotics and the combination of irradiation and antibiotics is even better, introducing a novel concept light assisted antibiotics. The investigated wavelength range was 249 nm to 338 nm with an approximate step of 5 nm. The novel concept that consists of a UV irradiation treatment followed by a tobramycin treatment can significantly reduce the amount of antibiotics needed for eradicating mature bacterial biofilms. The efficiency of the proposed light assisted antibiotics method was compared to combinatory antibiotic treatment and highly concentrated antibiotic monotherapy. The eradication efficacies, on mature biofilms, achieved by light assisted antibiotic and by the antibiotic monotherapy at approximately 10-fold higher concentration, were equivalent. The present achievement could motivate the development of light assisted antibiotic treatments for treating infections.

Ten-year follow-up on adoption of endodontic technology and clinical guidelines amongst Danish general dental practitioners.

OBJECTIVE: The aim of this study was to re-assess the adoption of certain endodontic technology and central treatment principles of root canal treatments as advocated by guidelines presented by the European Society of Endodontology. MATERIAL AND METHODS: The questionnaire included the same questions in 2003 and 2013. The general dental practitioners (GDPs) anonymously reported how frequent ('often', 'occasionally', and 'never') they used certain endodontic technology and adhered to central treatment principles. The statistical analyses were performed using Chi-squared test and Goodman-Kruskal's γ-coefficient as an association measure. RESULTS: The overall response rate of the 2013 group was 46.5% (n = 531). The frequencies of GDPs reporting often use of rubber dam, apex locator and rotary NiTi instruments were significantly higher (p < .0001) than in 2003, as well as reporting the use of composite resin for coronal sealing (p < .019). Adoption was significantly influenced by the factors gender (p = .601) and time since graduation (p = .361), and the cluster analyses revealed the neglected use of rubber dam to be associated with no established postoperative recall system. CONCLUSIONS: After 10 years, there was a higher frequency of GDPs who had adopted certain endodontic technologies. However, progress towards high-quality root canal treatment might be obstructed as the majority of GDPs avoids consistent use of rubber dam, and routinely neglects recalls for postoperative controls of their endodontic treatments.

Inactivation of Pseudomonas aeruginosa biofilm after ultraviolet light-emitting diode treatment: a comparative study between ultraviolet C and ultraviolet B.

The objective of this study was to test the inactivation efficiency of two different light-based treatments, namely ultraviolet B (UVB) and ultraviolet C (UVC) irradiation, on Pseudomonas aeruginosa biofilms at different growth stages (24, 48, and 72 h grown). In our experiments, a type of AlGaN light-emitting diodes (LEDs) was used to deliver UV irradiation on the biofilms. The effectiveness of the UVB at 296 nm and UVC at 266 nm irradiations was quantified by counting colony-forming units. The survival of less mature biofilms (24 h grown) was studied as a function of UV-radiant exposure. All treatments were performed on three different biological replicates to test reproducibility. It was shown that UVB irradiation was significantly more effective than UVC irradiation in inactivating P. aeruginosa biofilms. UVC irradiation induced insignificant inactivation on mature biofilms. The fact that the UVB at 296 nm exists in daylight and has such disinfection ability on biofilms provides perspectives for the treatment of infectious diseases.

Maxillary Sinus Impaction of a Core Carrier Causing Sustained Apical Periodontitis, Sinusitis, and Nasal Stenosis: A 3-year Follow-up.

INTRODUCTION: The aim was to present a case report of a full-length extrusion of an obturator's core carrier into the maxillary sinus, causing clinical symptoms from the nose region with differential diagnostics aspects, which, in turn, led to several surgical treatments of the nostrils before diagnosis and correct endodontic retreatment of a maxillary right first molar. A 36-year-old man presented in 2012 with complaints from the right nostril region. Medical treatment with antibiotics and surgical procedures because of nasal stenosis resulted only in partial improvement. Five years earlier, a root canal treatment was performed on the maxillary right first molar. Intraoral radiographs revealed 10-mm overfilling of root filling material into the maxillary sinus from the palatal root of tooth #3. METHODS: Before surgical removal of the excess root filling material, orthograde revision was performed. Cone-beam computed tomographic imaging was used to localize the position of the root filling material, which protruded through the maxillary sinus and reached the inferior nasal wall. RESULTS: Surgical removal from the palatal aspect revealed that the root filling material was a core carrier of an obturator. Scanning electron microscopy and transmission electron microscopy showed evidence of microbial biofilm on the core carrier as well as remnants of sinus mucosa. At the long-term follow-ups, the tooth had healed apically, and symptoms of nasal stenosis were markedly reduced. CONCLUSIONS: This case report represents a challenging differential diagnostic topic urging the importance of a medical and dental interdisciplinary dialogue. The use of cone-beam computed tomographic imaging was crucial for the surgical retreatment.

The antimicrobial effect of apical box versus apical cone preparation using iodine potassium iodide as root canal dressing: a pilot study.

PURPOSE: The purpose was to study the reduction of intra-canal microflora in premolars with apical periodontitis instrumented with either apical box or apical cone preparation and to provide measurements of intervention effects to allow proper power calculation in future clinical trials. METHODS: Twenty-four patients were centrally randomized to apical box preparation (size #60) or cone preparation (apical size #25). The groups were comparable regarding the presence of primary caries and type of coronal restoration. In the course of canal preparation each tooth was irrigated with 2.5% NaOCl (12 ml). Lastly, the canals were filled with 17% EDTA (2 × 30 s) and 5% iodine potassium iodide (IKI) for 10 min. The canals were sampled for micro-organisms on four occasions: before instrumentation, after instrumentation, after application of IKI dressing and at the beginning of the second appointment 1 week later. Between the treatment sessions, the root canals were sealed with IRM cement. In the laboratory, culture techniques were used to measure microbial growth, which was classified as: none, very sparse, sparse, moderate, heavy or very heavy. RESULTS: Initially, microbes were recovered in 88% of the teeth. Growth was classified as none in 35% of the teeth after instrumentation and in 50% after the application of IKI. Irrespective of the time of sampling, no significant difference in microbial growth reduction was observed between the two types of apical preparation. Based on the 1-week post-sampling, a power calculation revealed that over 900 patients are needed to show a difference of 9% between the two protocols tested. CONCLUSIONS: Future trials should be conducted using stringent protocols and as multi-centre trials for reaching the required information size.

Quality-Shaping Factors and Endodontic Treatment amongst General Dental Practitioners with a Focus on Denmark.

There is a gap between the endodontic outcome that can be achieved and the outcome observed on the basis of worldwide general dental practitioner data. The quality of root canal treatment (RCT) is shaped by the dentist's knowledge, attitude, and skills, but it may also be influenced by the patient's demands and degree of satisfaction. The topic has only been sparsely investigated. Although dental health has increased over the years in Denmark, the number of performed root fillings has also increased, probably because the number of tooth extractions have declined and more molar teeth have been treated. Caries appears to be the main cause for performing RCT and a preventive approach by employing stepwise excavation may reduce RCT, but this strategy does not remove the gap. Factors influencing RCT quality could be the status on adoption of nickel-titanium rotary technology, more focus on infection control (rubber dam use, knowledge of factors important for prognosis), as dentists often think that they are good at doing RCT, but often perform inadequately, an alteration of clinician's awareness of their performance in the context of dental practices, seems warranted. Finally, the development of new preventive modalities for pulp and apical inflammation are crucial.