| 1. |
- Addi, Simon, et al.
(författare)
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Interface gap size of manually and CAD/CAM-manufactured ceramic inlays/onlays in vitro.
- 2002
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Ingår i: Journal of Dentistry. - 0300-5712 .- 1879-176X. ; 30:1, s. 53-58
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Tidskriftsartikel (refereegranskat)abstract
- Objectives : To determine the fit of ceramic inlays manufactured using a recently introduced CAD/CAM-system (Decim) and of two types of laboratory-made heat-pressed ceramics (IPS Empress and Opc). Materials and methods : Extracted human premolars were prepared to receive mesio-occlusodistal (MOD) ceramic inlays, for which 10 Denzir, 10 IPS Empress, and 10 Opc were fabricated. The Denzir restorations were produced by the manufacturer of the CAD/CAM-system, and the IPS Empress and Opc by student dental technicians. Before luting the internal fit on the diestone models and on the premolars was determined using replicas. After luting on the premolars with a resin composite the marginal and internal fit were measured. The values were analyzed statistically using ANOVA and Scheffe's test at a significance level of p<0.05. Results : Before luting there were no significant differences ( p>0.05) in the internal gap width between the three systems studied when placed on their matching diestone models. When placed on the premolars a significant difference ( p<0.01) in the internal fit was seen between Empress and Opc before luting, whereas there were no significant differences ( p>0.05) between Empress and Denzir and between Opc and Denzir. Between the diestone models and the premolars there were significant differences ( p<0.01) in the internal fit, except for IPS Empress. After luting there were no significant differences ( p>0.05) between IPS Empress and Denzir, whereas the marginal gap width was significantly wider ( p<0.001) for Opc than for IPS Empress and Denzir. The internal fit was significantly ( p<0.001) wider for Opc than for IPS Empress, whereas there were no significant differences ( p>0.05) between IPS Empress and Denzir or between Opc and Denzir. Conclusion : After luting there were only slight differences in the fit between the restorations fabricated using the three different manufacturing techniques and ceramics. Therefore, long-term follow-up studies are needed to assess the clinical significance of the slight differences between the three systems.
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| 2. |
- Arvidsson, A., et al.
(författare)
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Chemical and topographical analyses of dentine surfaces after Carisolv™ treatment
- 2002
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Ingår i: Journal of Dentistry. - 0300-5712 .- 1879-176X. ; 30:2-3, s. 67-75
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. The aim of this study was to characterise the surface chemistry of cavities after chemomechanical caries excavation, and also to measure the surface topography after caries removal with Carisolv™ or burs, followed by acid etching. Methods. Fourier transform (FT)-Raman spectroscopy was used to study the relative amounts of organic material and minerals of sound enamel, dentine, and cavities, after caries excavation. Fourier transform infrared spectroscopy (FTIR) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) were used for detection of Carisolv™ substances (i.e. mainly sodium hypochlorite, amino acids, and the gelling agent carboxymethyl cellulose). In total, 19 carious and 11 sound extracted teeth were used for the chemical analyses. Topographic examination of 30 carious extracted teeth was performed with a contact profilometer. Results. The relative amounts of organic material and minerals did not significantly differ between sound dentine and the cavities after caries removal with burs or Carisolv™. The FTIR analyses indicated extremely small amounts of Carisolv™ substances at the cavity surface, but the LA-ICP-MS analyses did not confirm those findings. Furthermore, the topographical parameters did not significantly differ between etched cavities after caries removal using burs or Carisolv™. Conclusions. The chemical and topographical analyses in the present study imply that any differences between the cavities after caries excavation with burs or with Carisolv™ are insignificant. © 2002 Elsevier Science Ltd. All rights reserved.
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| 3. |
- Emami, N., et al.
(författare)
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Effect of light power density variations on bulk curing properties of dental composites
- 2003
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Ingår i: Journal of Dentistry. - : Elsevier BV. - 0300-5712 .- 1879-176X. ; 31:3, s. 189-196
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Tidskriftsartikel (refereegranskat)abstract
- Objective. The hypothesis that low light intensity and long but sufficient curing time can produce composites with volumetric shrinkage, degree of conversion (DC%) and Young's modulus (E-modulus) comparable to those of high light intensity cured composite was tested, when the contraction strain and heat generation were lower with Low Light intensity curing. Methods. Dental composites (Z100 and Z250, 3M ESPE) were investigated. Specimens were cured with Light intensities of 200, 450 and 800 mW/cm(2) for 140, 60 and 35 s from a distance of 7 mm. Strain-gages were used for contraction strain measurements. DC% was measured at the top and the bottom of 4 mm thick samples using FT-Raman spectroscopy. Volumetric polymerization shrinkage was determined using a water displacement method. E-modulus was determined in tension on composite specimens. Results. The results were analyzed using ANOVA and Duncan's multiple range tests and regular t-test. Polymerization stress Level decreased significantly (p < 0.05) when cured with 200 mW/cm(2) rather than with 800 mW/cm(2). Temperature rises were significantly different (p < 0.05) for different composites and light intensity values. Reduction in light intensity did not decrease the DC% values significantly at the top surfaces. The most dramatic differences existed between top and bottom surfaces (p < 0.05) rather than among curing groups. Measured E-modulus and volumetric shrinkage values were not significantly different (p > 0.05) between different light intensity groups. Conclusion. DC%, E-modulus and the volumetric shrinkage values in cured composites were not affected by low Light intensity, however, the contraction strain and polymerization's exotherm were decreased. Thus our results support the proposed hypothesis. Published by Elsevier Science Ltd.
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| 4. |
- Emami, Nazanin, et al.
(författare)
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Effect of light power density variations on bulk curing properties of dental composites
- 2003
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Ingår i: Journal of Dentistry. - 0300-5712 .- 1879-176X. ; 31:3, s. 189-196
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Tidskriftsartikel (refereegranskat)abstract
- Objective. The hypothesis that low light intensity and long but sufficient curing time can produce composites with volumetric shrinkage, degree of conversion (DC%) and Young's modulus (E-modulus) comparable to those of high light intensity cured composite was tested, when the contraction strain and heat generation were lower with low light intensity curing. Methods. Dental composites (Z100 and Z250, 3M ESPE) were investigated. Specimens were cured with light intensities of 200, 450 and 800 mW/cm2 for 140, 60 and 35 s from a distance of 7 mm. Strain-gages were used for contraction strain measurements. DC% was measured at the top and the bottom of 4 mm thick samples using FT-Raman spectroscopy. Volumetric polymerization shrinkage was determined using a water displacement method. E-modulus was determined in tension on composite specimens. Results. The results were analyzed using ANOVA and Duncan's multiple range tests and regular t-test. Polymerization stress level decreased significantly (p<0.05) when cured with 200 mW/cm2 rather than with 800 mW/cm2. Temperature rises were significantly different (p<0.05) for different composites and light intensity values. Reduction in light intensity did not decrease the DC% values significantly at the top surfaces. The most dramatic differences existed between top and bottom surfaces (p<0.05) rather than among curing groups. Measured E-modulus and volumetric shrinkage values were not significantly different (p>0.05) between different light intensity groups. Conclusion. DC%, E-modulus and the volumetric shrinkage values in cured composites were not affected by low light intensity, however, the contraction strain and polymerization's exotherm were decreased. Thus our results support the proposed hypothesis.
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| 5. |
- Ali, Shaymaa Abdulreda, et al.
(författare)
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Is tele-diagnosis of dental conditions reliable during COVID-19 pandemic? : Agreement between tentative diagnosis via synchronous audioconferencing and definitive clinical diagnosis
- 2022
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Ingår i: Journal of Dentistry. - : Elsevier. - 0300-5712 .- 1879-176X. ; 122
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To assess the reliability of synchronous audioconferencing teledentistry (TD) in making tentative diagnosis compared to definitive clinical face-to-face (CFTF) diagnosis; and whether agreement was influenced by dentist's experience, caller-patient relationship, and time of call. Methods: All patients calling the TD hotline during COVID-19 pandemic, triaged as emergency/ urgent and referred for CFTF care were included (N=191). Hotline dentists triaged the calls, made tentative audio-dentistry (AD) diagnosis, while dentists at point of referral made the definitive CFTF diagnosis. Cohen's weighted kappa (κ) assessed the extent of agreement between AD vs CFTF diagnosis. Results: There was significantly very good pair-wise agreement (κ = 0.853, P < 0.0001) between AD and CFTF diagnosis. AD diagnosis of pulpitis and periodontitis exhibited the most frequent disagreements. Tele-dentists with ≥ 20 years’ experience exhibited the highest level of agreement (κ =0.872, P < 0.0001). There was perfect agreement when mothers mediated the call (κ = 1, P < 0.0001), and very good agreement for calls received between 7 am-2 pm (κ = 0.880, P < 0.0001) compared to calls received between 2-10 pm (κ = 0.793, P < 0.0001). Conclusions: Remote tentative diagnosis using AD is safe and reliable. Reliability was generally very good but varied by dentist's experience, caller-patient relationship, and time of call. Clinical significance: The findings suggest that using AD in the home environment is safe and reliable, deploying providers with variable years of experience. The findings have generalizability potential to a variety of similar circumstances, healthcare settings and epi/pandemic situations.
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| 6. |
- Alturki, M, et al.
(författare)
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Biochemical characterisation of carious dentine zones using Raman spectroscopy.
- 2021
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Ingår i: Journal of dentistry. - : Elsevier BV. - 1879-176X .- 0300-5712. ; 105
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Tidskriftsartikel (refereegranskat)abstract
- Carious tissue discrimination in clinical operative caries management relies traditionally on the subjective hardness of carious dentine. Biochemical alterations within the lesion have the potential to discriminate the lesion zones objectively. This study aimed to determine the correlation between the biochemical proportions of amide I and phosphate moieties as these are the most prominent peaks found in dentine with the Knoop microhardness of carious dentine zones, using non-contact Raman spectroscopy. The null hypothesis investigated was that there was no correlation between Raman peak ratios, amide I: phosphateν1, and the Knoop microhardness within specific zones of a carious lesion.423 scan points from 20 carious dentine lesion samples examined using high-resolution Raman spectroscopy. The peak ratio of the characteristic vibration mode of amide I (1650 cm-1) and phosphate (960 cm-1) bands were calculated, following a straight line path through the lesion to the pulp and correlated to corresponding Knoop microhardness measurements.Using logistic regression analysis, clear correlations were found between the Knoop microhardness and Raman peak ratio cut-off values between caries-infected and caries-affected dentine (81.5 % sensitivity / 92.7 % specificity), with a lower specificity (2.7 %) found between caries-affected and sound dentine.This study concluded that non-contact Raman spectroscopy can be used in vitro to discriminate objectively between the different zones of a carious dentine lesion at high resolution, using the Raman peak ratios, amide I : phosphate ν1.Specific biochemical alterations have the potential to be used in-vitro and in-vivo to identify the end-point of selective carious lesion excavation.
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| 7. |
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| 8. |
- André, Maria, et al.
(författare)
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Effects of pretreatments and hydrothermal aging on biaxial flexural strength of lithium di-silicate and Mg-PSZ ceramics
- 2016
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Ingår i: Journal of Dentistry. - : Elsevier BV. - 0300-5712 .- 1879-176X. ; 55, s. 25-32
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To evaluate the effect of specimen thickness, pretreatment and hydrothermal aging on the biaxial flexural strength (BFS) of lithium di-silicate glass (e.max Cad) and magnesia-stabilized zirconia (ZirMagnum) ceramic discs. Methods: The e.max Cad discs was studied: i) crystallized, ii) crystallized and glazed and iii) crystallized, glazed and unglazed side etched with hydrofluoric acid. The ZirMagnum discs were studied: i) as delivered, ii) after sandblasting and iii) after heat treatment similar to veneering. Hydrothermal aging was simulated by autoclave treatment. Results: The BFS of all the ZirMagnum specimens was superior (p < 0.001) to all the e.max Cad specimens. Glazing the 0.4 mm e.max Cad discs reduced (p < 0.05) their BFS compared with the unglazed 0.8 mm specimens, whereas glazing of 0.8 mm discs had no influence (p > 0.05) on the strength. Etching and autoclaving of e.max Cad did not affect (p > 0.05) the BFS. For ZirMagnum sandblasting with 0.2 MPa or 0.6 MPa did not influence the biaxial flexural strength (p > 0.05), whereas heat treatment reduced (p < 0.01) the BFS of 0.6 MPa sandblasted ZirMagnum. Autoclaving reduced the strength (p < 0.05) compared with ZirMagnum as delivered, whereas autoclaving of the 0.6 MPa sandblasted and heat treated specimens did not influence (p > 0.05) the BFS. Glazing, etching and sandblasting increased (p < 0.05) surface roughness. Conclusions: The effects of glazing, heat treatment, aging and mechanical treatment of the materials evaluated should be considered since their strength could be affected. Clinical significance: Mechanical properties of restorations made from prefabricated ceramic blocks could be affected of various treatments and could change over time.
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| 9. |
- Astvaldsdottir, Alfheidur, et al.
(författare)
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Longevity of posterior resin composite restorations in adults : A systematic review
- 2015
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Ingår i: Journal of Dentistry. - : Elsevier BV. - 0300-5712 .- 1879-176X. ; 43:8, s. 934-954
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Forskningsöversikt (refereegranskat)abstract
- Objective: To conduct a systematic review of the literature on the longevity of posterior resin composite restorations in adults. Material and methods: A systematic literature search was conducted according to predetermined criteria for inclusion and exclusion. The studies selected were prospective clinical trials with a minimum follow-up time of 4 years, 40 restorations per experimental group and an annual attrition rate of less than 5%. Initially, abstracts and full-text articles were assessed independently and the assessment was subsequently agreed on by five reviewers. The methodological quality of the studies was assessed according to the Swedish Council on Health Technology Assessment (SBU) standard checklist for determining the extent to which studies meet basic quality criteria. Results: In all, the literature search identified 4275 abstracts and 93 articles were read in fulltext. There were eighteen studies which met the criteria for inclusion, eight of which were included in the analysis. There were 80 failures of restorations with a total follow-up time at risk for failure of 62,030 months. The overall incidence rate for all causes of failure was 1.55 lost restorations per 100 restoration years. The most common biological reason for failure (a total of 31 restorations) was secondary caries, with or without fracture of the restoration. The quality of the evidence was low. Conclusions: In an efficacy setting, the overall survival proportion of posterior resin composite restorations is high. The major reasons for failure are secondary caries and restoration fracture which supports the importance of adequate follow-up time. Clinical significance: The overall survival proportion of posterior composite restorations was high, but the results cannot be extrapolated to an effectiveness setting. The importance of adequate follow-up time is supported by the finding that secondary caries often occurred after 3 years or later.
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| 10. |
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