| 1. |
- Brundin, Malin, et al.
(författare)
-
DNA Binding to hydroxyapatite : a potential mechanism for preservation of microbial DNA
- 2013
-
Ingår i: Journal of Endodontics. - : Elsevier. - 0099-2399 .- 1878-3554. ; 39:2, s. 211-216
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Molecular methods are increasingly being deployed for analysis of the microbial flora in the root canal. Such methods are based on the assumption that recovered DNA is associated with the active endodontic infection, yet paleomicrobiology research is based on the recovery of ancient DNA from centuriesold tooth and bone samples, which points to considerable longevity of the DNA molecule in these tissues. The main component of dentin and bone is the mineral hydroxyapatite. This study assessed DNA binding to hydroxyapatite and whether thiS binding affinity stabilizes the DNA molecule in various media.Methods: DNA was extracted from Fusobacterium nucleatum and added to ceramic hydroxyapatite for 90 minutes. The DNA-bound hydroxyapatite was incubated in different media (ie, water, sera, and DNase I) for up to 3 months. At predetermined intervals, the recovery of detectable DNA was assessed by releasing the DNA from the hydroxyapatite using EDTA and evaluating the presence of DNA by gel electrophoresis and polymerase chain reaction (PCR) amplification.Results: When incubated with hydroxyapatite, nonamplified DNA was detectable after 3 months in water, sera, and DNase I. In contrast, DNA incubated in the same media (without hydroxyapatite) decomposed to levels below the detection level of PCR within 3 weeks, with the exception of DNA in sera in which PCR revealed a weak positive amplification product.Conclusions: These results confirm a specific binding affinity of hydroxyapatite for DNA. Hydroxyapatite-bound DNA is more resistant to decay and less susceptible to degradation by serum and nucleases, which may account for the long-term persistence of DNA in bone and tooth.
|
|
| 2. |
- Brundin, Malin, et al.
(författare)
-
Preservation of bacterial dna by human dentin
- 2014
-
Ingår i: Journal of Endodontics. - : Elsevier BV. - 0099-2399 .- 1878-3554. ; 40:2, s. 241-245
-
Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: The capacity of dentin and collagen to bind DNA and protect against spontaneous and nuclease-induced degradation was evaluated individually and by the incubation of DNA with nuclease-producing bacteria in a mixed culture.METHODS: Extracted Fusobacterium nucleatum DNA was incubated with dentin shavings or collagen for 90 minutes. The DNA-bound substrates were incubated in different media (water, sera, and DNase I) for up to 3 months. Amplifiable DNA was released from dentin using EDTA,or from collagen using proteinase K, and evaluated by polymerase chain reaction (PCR). The stability of dentin-bound DNA was also assessed in a mixed culture (Parvimonas micra and Pseudoramibacter alactolyticus) containing a DNase-producing species, Prevotella intermedia. Samples were analyzed for amplifiable DNA.RESULTS: In water, dentin-bound DNA was recoverable by PCR at 3 months compared with no detectable DNA after 4 weeks in controls (no dentin). DNA bound to collagen was detectable by PCR after 3 months of incubation in water. In 10% human sera, amplifiable DNA was detectable at 3 months when dentin bound and in controls (no dentin). In mixed bacterial culture, dentin-bound DNA was recoverable throughout the experimental period (3 months), compared with no recoverable F. nucleatum DNA within 24 hours in controls (no dentin).CONCLUSIONS: There is a strong binding affinity between DNA and dentin, and between DNA and serum proteins or collagen. These substrates preserve DNA against natural decomposition and protect DNA from nuclease activity, factors that may confound molecular analysis of the endodontic microbiota yet favor paleomicrobiological studies of ancient DNA.
|
|
| 3. |
- Chávez de Paz, Luis E.
(författare)
-
Development of a Multispecies Biofilm Community by Four Root Canal Bacteria
- 2012
-
Ingår i: Journal of Endodontics. - : Elsevier. - 0099-2399 .- 1878-3554. ; 38:3, s. 318-323
-
Tidskriftsartikel (refereegranskat)abstract
- The development of multispecies biofilm models are needed to explain the interactions that take place in root canal biofilms during apical periodontitis. The aim of this study was to investigate the ability of 4 root canal bacteria to establish a multispecies biofilm community and to characterize the main structural, compositional, and physiological features of this community. Methods Four clinical isolates isolated from infected root canals, Actinomyces naeslundii, Lactobacillus salivarius, Streptococcus gordonii, and Enterococcus faecalis, were grown together in a miniflow cell system. Simultaneous detection of the 4 species in the biofilm communities was achieved by fluorescence in situ hybridization in combination with confocal microscopy at different time points. The LIVE/DEAD BacLight technique (Molecular Probes, Carlsbad, CA) was used to assess cell viability and to calculate 3-dimensional architectural parameters such as biovolume (μm3). Redox fluorescence dye 5-cyano-2,3-ditolyl tetrazolium chloride was used to assess the metabolic activity of biofilm bacteria. Results The 4 species tested were able to form stable and reproducible biofilm communities. The biofilms formed in rich medium generally showed continuous growth over time, however, in the absence of glucose biofilms showed significantly smaller biovolumes. A high proportion of viable cells (>90%) were generally observed, and biofilm growth was correlated with high metabolic activity of cells. The community structure of biofilms formed in rich medium did not change considerably over the 120-hour period, during which E. faecalis, L. salivarius, and S. gordonii were most abundant. Conclusions The ability of 4 root canal bacteria to form multispecies biofilm communities shown in this study give insights into assessing the community lifestyle of these microorganisms in vivo. This multispecies model could be useful for further research simulating stresses representative of in vivo conditions.
|
|
| 4. |
- Chávez de Paz, Luis Eduardo, et al.
(författare)
-
The effects of antimicrobials on endodontic biofilm bacteria
- 2010
-
Ingår i: Journal of Endodontics. - : Elsevier. - 0099-2399 .- 1878-3554. ; 36:1, s. 70-77
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction In the present study, confocal microscopy, a miniflow cell system, and image analysis were combined to test in situ the effect of antimicrobials and alkali on biofilms of Enterococcus faecalis, Lactobacillus paracasei, Streptococcus anginosus, and Streptococcus gordonii isolated from root canals with persistent infections. Methods Biofilms formed for 24 hours were exposed for 5 minutes to alkali (pH = 12), chlorhexidine digluconate (2.5%), EDTA (50 mmol/L), and sodium hypochlorite (1%). The biofilms were then characterized by using fluorescent markers targeting cell membrane integrity (LIVE/DEAD) and metabolic activity (5-cyano-2,3-ditolyl tetrazolium chloride and fluorescein diacetate). In addition, the biofilm architecture and the extent to which coating of the substrate surface with collagen influenced the resistance pattern to the chemicals were also analyzed. Results NaOCl (1%) affected the membrane integrity of all organisms and removed most biofilm cells. Exposure to EDTA (50 mmol/L) affected the membrane integrity in all organisms but failed to remove more than a few cells in biofilms of E. faecalis, L. paracasei, and S. anginosus. Chlorhexidine (2.5%) had a mild effect on the membrane integrity of E. faecalis and removed only 50% of its biofilm cells The effects were substratum-dependent, and most organisms displayed increased resistance to the antimicrobials on collagen-coated surfaces. Conclusions The biofilm system developed here was sensitive and differences in cell membrane integrity and removal of biofilm cells after exposure to antimicrobials commonly used in endodontics was discernible.
|
|
| 5. |
- Dawson, Victoria, et al.
(författare)
-
Periapical status of non-root-filled teeth with resin composite, amalgam, or full crown restorations : a cross-sectional study of a Swedish adult population
- 2014
-
Ingår i: Journal of Endodontics. - : Elsevier. - 0099-2399 .- 1878-3554. ; 40:9, s. 1303-1308
-
Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Experimental studies show that dental pulp cells respond unfavorably to contact with resin composite restorative material. Hypothetically, in a random population, the frequency of apical periodontitis should be higher for teeth restored with resin composite than with amalgam. Therefore, the aim was to compare the periapical status of non-root-filled teeth restored with resin composite, amalgam, or laboratory-fabricated crowns in an adult Swedish population. METHODS: The subjects comprised 440 individuals from a randomly selected sample of 1,000 adult residents of a Swedish county. The type, material, and quality of the restorations were recorded for all non-root-filled teeth by clinical examination and intraoral clinical photographs. Periapical status was evaluated on panoramic radiographs. The association between periapical status and type, material, and quality of the restorations was analyzed using the chi-square test and logistic regression analysis. RESULTS: There was no significant difference in the frequency of apical periodontitis (AP) between teeth restored with resin composite or amalgam (1.3% and 1.1%, respectively). The frequency of AP for teeth restored with laboratory-fabricated crowns was significantly higher (6.3%). Regression analysis showed no association between AP and resin composite restorations but a significant association with laboratory-fabricated crowns. CONCLUSIONS: The results indicate that the risk of damage to the pulp-dentin complex from exposure to resin composite material and dentin bonding agents shown in experimental studies is not reflected in the clinical setting. However, in the study sample, AP was diagnosed in a significantly higher proportion of teeth restored with laboratory-fabricated crowns.
|
|
| 6. |
- Jaramillo, David E., et al.
(författare)
-
Decreased Bacterial Adherence and Biofilm Growth on Surfaces Coated with a Solution of Benzalkonium Chloride
- 2012
-
Ingår i: Journal of Endodontics. - : Elsevier. - 0099-2399 .- 1878-3554. ; 38:6, s. 821-825
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction Secondary biofilm formation by oral bacteria after breakdown/fracture of temporary or permanent restorations imposes a challenge to the outcome of root canal treatment. This study focuses on benzalkonium chloride (BAK) coating on dentin or polystyrene surfaces and its influence on the early adhesion and biofilm formation by oral and root canal bacteria. Methods Microbial adhesion and biofilm growth on surfaces coated with BAK were analyzed qualitatively with a dentin disk model and quantitatively with a mini-flow cell biofilm model. Cell viability and total biovolume were analyzed by the LIVE/DEAD technique. The repelling effect of surfaces coated with BAK was compared with NaOCl. Uncoated surfaces were used as controls. Results Scanning electron microscope images in the dentin disk model revealed that very sparse biofilms were formed on NaOCl- and BAK-coated dentin surfaces. In contrast, biofilms formed on uncoated dentin were clearly visible as numerous irregularly distributed aggregates of rods and cocci. In the mini-flow cell system, confocal laser scanning microscope analysis confirmed that biofilms formed on NaOCl- and BAK-coated surfaces showed significantly less adhesion (2 hours) and biovolume accumulation (24 and 96 hours) compared with the uncoated controls (P < .01). Furthermore, cell viability assessments showed that on uncoated controls the viability measurements were high (>89%) as well as on BAK-coated surfaces (88% viable cells). However, cell viability was significantly reduced on NaOCl-coated surfaces (59% viable cells). Conclusions This study illustrates that surface coating with a surfactant solution containing BAK does not cause cell membrane damage but might interfere with cell mechanisms of adhesion. Investigations into the clinical utility of BAK as an antibiofilm medication are warranted.
|
|
| 7. |
- Malmgren, B
(författare)
-
Ridge preservation/decoronation
- 2013
-
Ingår i: Journal of endodontics. - : Elsevier BV. - 1878-3554 .- 0099-2399. ; 35:2, s. 164-169
-
Tidskriftsartikel (refereegranskat)
|
|
| 8. |
- Merdad, Khalid, et al.
(författare)
-
Caries susceptibility of endodontically versus nonendodontically treated teeth.
- 2011
-
Ingår i: Journal of endodontics. - : Elsevier BV. - 1878-3554 .- 0099-2399. ; 37:2, s. 139-42
-
Tidskriftsartikel (refereegranskat)abstract
- NTRODUCTION: The aim of the present investigation was to evaluate the caries susceptibility of endodontically versus nonendodontically treated teeth in relation to dental plaque-related factors. METHODS: Twenty patients with 2 endodontically treated teeth (ETT) each were examined regarding cariogenic microflora of proximal plaque, in situ plaque pH drop after a sucrose rinse (Stephan curve), and de novo plaque formation. Recurrent caries and the quality of the coronal fillings/crowns of these teeth were also evaluated. ETT were compared with contralateral, nonendodontically treated teeth (NETT). RESULTS: Irrespective to the type of restoration, Streptococcus mutans count, de novo plaque formation, and recurrent caries were higher on the surface of ETT compared with NETT (P < .05). Moreover, the initial (resting) pH in plaque was significantly lower (P < 0.05) in ETT. CONCLUSIONS: ETT showed an increased susceptibility to caries as a result of either alteration in their biological environment or inadequacy of the marginal fit of the dental restoration. Clinicians should be aware of this risk.
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
- Soǧur, Elif, et al.
(författare)
-
Does a combination of two radiographs increase accuracy in detecting acid-induced periapical lesions and does it approach the accuracy of cone-beam computed tomography scanning?
- 2012
-
Ingår i: Journal of Endodontics. - : Elsevier BV. - 0099-2399. ; 38, s. 131-136
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: The purpose of this study was to determine whether the use of a combination of 2 images (storage phosphor plates [SPPs] and F-speed films [Eastman Kodak, Rochester, NY]) with a 10° difference in horizontal beam angulation resulted in better detectability of chemically created periapical defects than when only 1 image was used and whether a detectability as good as that achieved by limited cone-beam computed tomography (LCBCT) scanning could be achieved. Methods: Lesions were created by 1, 1.5, and 2 hours of acid application apical to extracted teeth in jaw specimens. After repositioning, teeth were radiographed with Accu-I-Tomo LCBCT, Digora Optime SPP system, and F-speed films. The SPPs and films were exposed at 0° and 10° horizontal angulations. The diagnostic accuracy (Az) was compared using 2-way analysis of variance; pair-wise comparisons were performed using the post hoc t test. Kappa was used to measure interobserver agreement. Results: A combination of 2 exposures with a 10° difference in horizontal angulation caused an increase, although not statistically significant, in the accuracy of both films and SPPs for all acid durations (P >.05) compared with when only 1 exposure was used. The accuracy did not approach that of LCBCT. Conclusions: Using a combination of 2 exposures instead of 1 did not significantly increase the accuracy in detecting acid-induced lesions at the apices of single-rooted premolars. The accuracy of LCBCT was superior. Copyright © 2012 American Association of Endodontists.
|
|
