Biomedical subjects

M F Burrow

Publications and source records attributed to M F Burrow.

At least 19 recordsLinked to original sources

PubMed2007

Surface characteristics of aesthetic restorative materials - an SEM study.

To determine the degree of surface roughness of glass-ionomer cements (GICs) and polyacid-modified resin composite (PAMRC) after polishing and immersion in various foodstuffs. Three tooth-coloured restorative materials were used: a PAMRC (F2000), a conventional glass-ionomer cement (CGIC) (Fuji IX) and a resin-modified glass-ionomer cements (RM-GIC) (Fuji II LC). Disk-shaped specimens were prepared and tested with either a plastics matrix finish or after polishing with wet silicon carbide papers up to 2000-grit. All specimens were immersed in 37 degrees C-distilled water for 1 week, followed by three different foodstuffs (red wine, coffee or tea) for a further 2 weeks. Replicas of specimens were prepared by taking polyvinyl siloxane impressions, casting in epoxy resin, gold sputter-coating and examining using a Field-Emission Scanning Electron Microscope. The polished and matrix finish specimens of F2000 showed many microcracks at low magnification, and eroded surfaces with missing and protruding particles at high magnification in the polished specimens. The surface-polished specimens of Fuji II LC were considerably rougher than the matrix-finish specimens, with large voids and protruding filler particles. The effects of foodstuffs on Fuji II LC and F2000 were not noticeable. The CGIC became noticeably rougher after exposure to coffee and tea. All specimens had the smoothest surface when they were cured against a plastics matrix strip, and all materials had a rougher surface after polishing. None of the foodstuffs produced a perceptible increase in roughness on RM-GIC and PAMRC surfaces, whereas coffee and tea markedly increased the surface roughness of Fuji IX.

Coffee↗

PubMed2006

Effect of static loading of dentin beams at various pH levels.

Noncarious cervical lesions have a multifactorial etiology. Mechanical stress has been identified as one of the factors, but little evidence exists for its cause-effect relationship. This study was conducted at three different pH levels to observe the surface loss on dentin beams under tension and compression. Bovine dentin beams (10 x 3.75 x 1.45 mm) were fixed at one end and immersed in 0.1 M lactic acid solution at pH levels 4.5 (n = 20), 7 (n = 20), and 10 (n = 20) for 5 days under a load of 6.5 N (663 g). The mean surface loss was more on the surface under compression than that under tension at pH 4.5 and pH 7 than at pH 10. Also, the surface loss on the beams decreased as the distance from the fixed end increased. It was concluded that stress and lower pH both increase surface loss at the fixed end of the beam, which in a tooth represents the cervical region.

Animals↗

PubMed2006

Effect of loading and pH on the subsurface demineralization of dentin beams.

It is important to understand subsurface dentin demineralization and caries from the clinical perspective as dentin properties are modified under acidic conditions and mechanical loading. This study was conducted to observe the subsurface demineralization of dentin beams at three different pH levels under tension and compression. Bovine dentin beams (10 x 3.75 x 1.45 mm) were fixed at one end and immersed in 0.1 M lactic acid solution at pH levels 4.5, 7, and 10 for 5 days under a load of 6.5 N (663 g), and the subsurface demineralization depth was measured using a polarized light microscope. The mean subsurface demineralization depth was more subjacent to the surface under compression than that under tension at pH 4.5 and decreased as the distance from the fixed end increased. No subsurface demineralization was observed at pH 7 or 10. It was concluded that both stress and low pH are associated with increased subsurface demineralization at the fixed end of the beam.

Animals↗

PubMed2006

Resin adhesion to caries-affected dentine after different removal methods.

BACKGROUND: Caries-affected dentine is the common bonding substrate when treating a patient. At present, there are many methods used for caries removal. The aim of this study was to evaluate the microtensile bond strength of two adhesives (Clearfil Protect Bond and OptiBond Solo Plus Total-Etch) to caries-affected dentine after three different caries removal methods. METHODS: Extracted carious human third molars were used and caries-affected dentine surfaces were obtained from one of the three removal methods: (i) round steel bur in a slow-speed handpiece; (ii) Er:YAG laser; or (iii) 600-grit silicon carbide abrasive paper. Each of the adhesives was used to bond resin composite to the caries-affected dentine according to the manufacturers' instructions. Hourglass-shaped specimens were prepared and stressed in tension at 1mm/min. Data were analysed using two-way analysis of variance and least significant difference test. RESULTS: Clearfil Protect Bond showed significantly lower bond strength than OptiBond Solo Plus Total-Etch after caries removal with round steel bur, but the opposite was found for specimens treated with silicon carbide abrasive paper. For laser-treated dentine, no significant differences between the adhesives were revealed. CONCLUSIONS: Besides the differences in adhesives, different caries removal methods seem to influence resin adhesion to caries-affected dentine.

Analysis of Variance↗

PubMed2006

The pH change after HCl titration into resting and stimulated saliva for a buffering capacity test.

BACKGROUND: Saliva collection can provide clinical information about individual patients. However, a correlation between ranking buffering capacity using resting and stimulated saliva is still unknown. The aim of this study was to evaluate the pH change after HCl titration into resting and stimulated saliva for a salivary buffering capacity test. METHODS: Resting and stimulated saliva (by chewing paraffin wax) were collected from 80 patients. After the pH of both saliva samples was measured using a hand-held pH meter, the saliva samples were titrated with 0.1N HCl to evaluate the buffering capacity. Correlations of ranking buffering capacity (high, medium, low) between stimulated saliva and resting saliva with 30 microL HCl titration and between stimulated saliva and resting saliva with 40 microL HCl titration were statistically analysed by Spearman Rank Correlation Test (p < 0.05). RESULTS: At 50 microL HCl titration, stimulated saliva buffering capacities were ranked into high (above pH 5.5), medium (pH from 5.5 to 4.5) and low (below pH 4.5). At 30-40 microL HCl titration, the resting saliva buffering capacities were ranked into the same categories. Spearman Rank Correlation indicated significant positive coefficients for the stimulated saliva and resting saliva buffering capacity at 30 microL titration and the stimulated saliva and resting saliva at 40 microL titration. CONCLUSION: Stimulated saliva is more resistant to variation in pH change during HCI titration than resting saliva. Stimulated saliva sampling is a good method to determine buffering capacity during a comprehensive oral health assessment.

Adolescent↗

PubMed2006

Comparison of microshear bond strengths of four self-etching bonding systems to enamel using two test methods.

BACKGROUND: Recent advances in enamel and dentine adhesive technology have resulted in the emergence of many new adhesive systems. Self-etching bonding systems do not require a separate etching step and the newest systems are the "all-in-one" systems which combine etching, priming and bonding into a single application. This study reports laboratory enamel microshear bond strengths of a self-etching priming and three all-in-one systems and also evaluates two different microshear bond test methods. METHODS: One hundred and nineteen enamel specimens were bonded (0.8 mm diameter) with either Clearfil Protect Bond (Kuraray), Xeno III (Dentsply), G Bond (GC) or One-Up Bond F (Tokuyama) using Palfique Estelite resin composite and stored in 37 degrees Celsius water for seven days. The microshear bond test method used either a blade or wire to apply the shear stress. Results were analysed with one-way ANOVA and post hoc (Tukey) multiple comparison analysis. RESULTS: Clearfil Protect Bond demonstrated higher and more consistent bond strengths than Xeno III, G Bond or One-Up Bond F. The wire method showed much greater reliability in results, with a coefficient of variation half that of the blade method. CONCLUSIONS: All-in-one adhesives seem to be less reliable than the two-step self-etching priming adhesive when bonding to enamel. Test method can significantly affect results in the microshear bond test method.

Acid Etching, Dental↗

PubMed2005

Microhardness and Ca:P ratio of carious and Carisolv treated caries-affected dentine using an ultra-micro-indentation system and energy dispersive analysis of x-rays--a pilot study.

BACKGROUND: This study aimed to evaluate microhardness and chemical analysis of carious and caries-affected dentine. The hypothesis tested was that calcium:phosphorous (Ca:P) ratios correlate with microhardness values. METHODS: Four carious human third molars were sectioned through the caries lesion in the mesiodistal longitudinal plane. One half of each lesion underwent carious dentine removal using Carisolv gel. The cut surfaces were polished, microhardness tested using an Ultra-Micro-Indentation System (UMIS) and elemental analysis performed using energy dispersive analysis of x-rays (EDAX). RESULTS: The microhardness of carious dentine decreased gradually towards the cavity floor, but that for caries-affected dentine showed more variation with depth, having a mean hardness of (0.63 +/- 0.18) GPa. Ca:P ratios of carious dentine varied among the four specimens. The mean Ca:P ratio of caries-affected dentine was 1:2.03 +/- 0.08. The hypothesis was accepted for active lesions. CONCLUSIONS: The use of Carisolv to excavate carious tissue can be as effective as rotary instrumentation.

Adult↗

PubMed2005

Two-year clinical evaluation of One-Up Bond F in noncarious cervical lesions.

PURPOSE: To evaluate the retention of restorations placed in non-undercut, noncarious cervical lesions using One-Up Bond F and Palfique Estelite resin composite. MATERIALS AND METHODS: Fifty-one non-undercut, noncarious cervical lesions were restored with One-Up Bond F and Palfique Estelite in 15 patients (mean age 57.7 years). Teeth were cleaned with pumice and water and restored following the manufacturer's instructions. Restorations were evaluated at 6 months, 1 and 2 years for presence or absence, and for the degree of marginal staining using standardized colour photographs for comparison. RESULTS: At 1 year, 42 restorations were evaluated, and all were intact. Slight marginal staining was observed in three restorations. At 2 years, 37 restorations were evaluated from 11 patients, and all were intact. Marginal staining was observed around nine restorations. ANOVA for marginal staining showed a significant increase of staining at both the enamel and cervical margins over the 2 years of the study. No caries was detected in association with any restoration. CONCLUSION: Although a number of restorations could not be evaluated, the retention of 100% at 2 years showed very good promise for the treatment of noncarious cervical lesions. The marginal staining was limited to a small number of patients.

Adolescent↗

PubMed2004

Influence of food-simulating solutions and surface finish on susceptibility to staining of aesthetic restorative materials.

OBJECTIVES: To determine the degree of surface staining of resin-based composites (RBCs) and glass-ionomer cements (GICs) after immersion in various stains and food-simulating solutions (FSS). METHODS: Six tooth-coloured restorative materials were used: a light-cured microfilled RBC (Durafil, Kulzer), a light-cured microglass RBC (Charisma, Kulzer), a polyacid-modified RBC (F2000, 3M/ESPE), a conventional GIC (Fuji IX, GC) and two resin-modified GICs (Fuji II LC, GC; Photac Fil, 3M/ESPE). Disk-shaped specimens were prepared and tested with either a matrix finish or polished using wet silicon carbide papers up to 2000 grit. All specimens were immersed in 37 degrees C distilled water for 1 week, followed by three different FSS (water, 10% ethanol, Crodamol GTCC) and five stains (red wine, coffee, tea, soy sauce and cola) for a further 2 weeks. Three specimens of each material for each stain were tested. Colour coefficients (CIE L* a* b*) were measured by a spectrophotometer after each treatment. The change in colour (DeltaEn) was calculated using the formula: DeltaEn=[(DeltaLn+(Deltaa(n))2+(Deltab(n))2]1/2. RESULTS: Distilled water caused no perceptible colour change as tested by ANOVA and Tukey's tests. The effect of surface finish on staining was not statistically significant (P>0.05). There was no strong interaction between FSS and stains or between FSS and materials. There was a strong interaction between surface and material, and stain and material (P<0.001). CONCLUSIONS: All materials were susceptible to staining by all stains especially coffee, red wine and tea; Fuji IX showed the least susceptibility and F2000 the greatest.

Analysis of Variance↗

PubMed2004

Adhesive restorative materials: a review.

'Adhesive' restorative dentistry originated with the work of Buonocore in 1955 in bonding resin to etched enamel. Since then, adhesive materials and techniques have developed at a rapid rate. The first chemically adhesive material (zinc polycarboxylate cement) was marketed in the late 1960s, and glass-ionomer cements and dentine bonding agents have since become available. This review focuses on the latter two products. Glass-ionomer cements have a particular role in adhesive dentistry because of their reliable chemical adhesion to enamel and dentine, and because of their apparent ability to promote the remineralization of 'affected' dentine. Dentine bonding agents have undergone marked changes in presentation over the last 15 years, but all have an essentially similar bonding system, that of hybrid layer formation. However, the most recent systems have limited clinical data supporting their use.

Dental Bonding↗

PubMed2003

Microtensile bond strengths to caries-affected dentine treated with Carisolv.

BACKGROUND: Little information is available regarding the bonding performance of adhesive restorative materials to caries-affected dentine after the use of Carisolv. The aim of this study was to compare the microtensile bond strengths of two resin-based adhesives, a conventional glass ionomer cement and resin modified glass ionomer cement to 'normal' dentine and caries-affected dentine after Carisolv treatment. METHODS: Specimens were prepared using molar teeth with small carious lesions. Caries was removed with the Carisolv solution and the whole surface was bonded with either SE Bond, One Coat Bond, Fuji IX or Fuji II LC. After 24 hours, specimens were prepared for the microtensile bond strength test and stressed in tension at 1 mm/min until rupture of the bond. Mean bond strengths and mode of failure were determined and analysed with the LSD test and chi square test respectively. RESULTS: The results showed no statistical difference for SE Bond, One Coat Bond or Fuji IX, but a difference was observed for the resin-modified GIC, Fuji II LC. CONCLUSIONS: It was concluded that carious dentine treated with Carisolv did not affect the adhesion of the adhesive restorative materials tested in this study with the exception of Fuji II LC.

Adhesiveness↗

PubMed2003

Pits and fissures: relative space contribution in fissures from sealants, prophylaxis pastes and organic remnants.

BACKGROUND: Previous studies by the authors have looked at the nature of the fissure system of human permanent molars and premolars, and has provided evidence for the presence of a prismless layer of enamel. It was noted during these studies that the fissure spaces were often occupied by material other than the fissure sealant. The aim of this study was to define these materials and to look at the percentage contribution of each to the sealed fissure space. METHODS: A sample of teeth, both molars and premolars, were sealed with an unfilled fissure sealant after prophylaxis with a coloured prophylaxis paste. In one group, the crown of the tooth was removed by dissolution in hydrochloric acid following placement of the sealant. This revealed a negative image of the fissure system and its contents. The second group of teeth was sectioned following sealing, and the contents of the fissure space were analyzed. RESULTS: The negative image of the fissure system displayed the fissure contents by colour and the sectioned teeth were able to be computer analyzed to establish the relative contribution of sealant, prophylaxis paste and organic material to the fissure space. CONCLUSIONS: Sealant contribution was in the range of 14-96 per cent, prophylaxis paste from 0-50 per cent and organic remnants 0-55 per cent. The presence of these last two components could contribute to sealant loss.

Bicuspid↗

PubMed2003

Clinical evaluation of an 'all-in-one' bonding system to non-carious cervical lesions--results at one year.

BACKGROUND: The recent trend in using dentine adhesives is to simplify the number of steps required for bonding. The simplest are now the so-called 'all-in-one' products which combine the etching, priming and bonding steps into a single application. However, few clinical trials have been reported using this type of material. The current study reports the one-year results of a clinical trial with One-Up Bond F and Palfique Estilite resin composite. METHODS: Fifty-one non-undercut non-carious cervical lesions were restored with One-Up Bond F and Palfique Estilite in 15 patients (mean age 57.5 years). Restorations were evaluated at six months and one year for presence or absence and for marginal staining using standardized colour photographs for comparison. RESULTS: At one year, 42 restorations could be evaluated and all were intact. Slight marginal staining was observed around three restorations but was considered to be of no clinical significance. CONCLUSIONS: One-Up Bond F with Palfique Estelite shows good promise for the restoration of non-carious cervical lesions.

Adolescent↗

PubMed2003

Incorporation of casein phosphopeptide-amorphous calcium phosphate into a glass-ionomer cement.

Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) nanocomplexes have been shown to prevent demineralization and promote remineralization of enamel subsurface lesions in animal and in situ caries models. The aim of this study was to determine the effect of incorporating CPP-ACP into a self-cured glass-ionomer cement (GIC). Incorporation of 1.56% w/w CPP-ACP into the GIC significantly increased microtensile bond strength (33%) and compressive strength (23%) and significantly enhanced the release of calcium, phosphate, and fluoride ions at neutral and acidic pH. MALDI mass spectrometry also showed casein phosphopeptides from the CPP-ACP nanocomplexes to be released. The release of CPP-ACP and fluoride from the CPP-ACP-containing GIC was associated with enhanced protection of the adjacent dentin during acid challenge in vitro.

Analysis of Variance↗

PubMed2002

Long-term quantification of the release of monomers from dental resin composites and a resin-modified glass ionomer cement.

This study quantified the release of monomers from polymerized specimens of four commercially available resin composites and one glass ionomer cement immersed in water:ethanol solutions. Individual standard curves were prepared from five monomers: (1) triethylene glycol dimethacrylate (TEGDMA), (2) 2-hydroxy-ethyl methacrylate (HEMA), (3) urethane dimethacrylate (UDMA), (4) bisphenol A glycidyl dimethacrylate (BISGMA), and (5) bisphenol A. The concentration of the monomers was determined at Days 1, 7, 30, and 90 with the use of electrospray ionization/mass spectrometry. Data were expressed in mean micromol per mm(2) surface area of specimen and analyzed with Scheffe's test (p<0.05). The following monomers were found in water: monomers (1) and (2) from Delton sealant, monomer (5) from ScotchBond Multipurpose Adhesive and Delton sealant, monomer (3) from Definite and monomer (4) from Fuji II LC, ScotchBond Multipurpose Adhesive, Synergy and Definite. All these monomers increased in concentration over time, with the exception of monomer (1) from Delton sealant. Monomers (3) and (5) were found in extracts of materials despite their absence from the manufacturer's published composition. All monomers were released in significantly higher concentrations in water:ethanol solutions than in water. The greatest release of monomers occurred in the first day. The effect of the measured concentrations of monomers (1-5) on human genes, cells, or tissues needs to be considered with the use of a biological model.

Acrylic Resins↗

PubMed2002

A comparison of microtensile bond strengths of several dentin bonding systems to primary and permanent dentin.

OBJECTIVES: Limited information exists with regard to the adhesive ability of glass ionomer cements (GIC) and recently developed resin-based dentin bond systems to primary dentin. The aim of this study was to compare the microtensile bond strength of a conventional GIC (Fuji IX), a resin-modified GIC (Fuji II LC), and two resin-based dentin adhesives (Prime and Bond NT with NRC and Single Bond). The bonded interfaces were also observed using field emission electron microscopy(FE-SEM). METHODS: Microtensile bond test specimens were prepared on superficial dentin of primary and permanent molars. The specimens were bonded according to each manufacturer's instructions except for Prime and Bond NT/NRC which used Silux Plus resin composite instead of Dyract. Hour-glass shaped specimens were created (diameter of 1.2+/-0.02 mm) and stressed in tension at a crosshead speed of 1mm/min. Results were analyzed using two-way ANOVA and LSD test, fracture modes were analyzed using the Mann-Whitney U-test and Kruskall-Wallis test. Twelve specimens were prepared for each material on primary and permanent dentin. Samples were prepared in the same manner, then critical point dried, fractured and sputter-coated for the FE-SEM observations. RESULTS: Two-way ANOVA showed the overall bond strengths were greater for the permanent dentin compared with primary dentin. However, for individual material comparisons no differences among the bond strengths to primary and permanent dentin for Fuji IX (9.7, 12.2 MPa), Fuji II LC (16, 20.1 MPa), Prime & Bond NT/NRC (18.1, 21.6 MPa) and Single Bond (18.2, 21.6 MPa), were detected. However, Fuji IX bond strengths were significantly lower than the other systems tested when bonded to either primary or permanent dentin (p<0.05). Failure mode showed cohesive failure of GIC and mostly adhesive failure for the resin-based adhesives. The FE-SEM observations showed hybrid-like layer formation for the GIC materials and hybrid layer formation for the resin-based adhesives. SIGNIFICANCE: The materials tested would be suitable for bonding to either primary or permanent dentin, but the resin-modified GIC or resin-based systems are likely to provide a stronger bond than the conventional GIC, Fuji IX.

Acid Etching, Dental↗

PubMed2002

Long-term tensile bond durability of two different 4-META containing resin cements to dentin.

OBJECTIVES: This study was conducted to evaluate the tensile bond durability of two different types of 4-META containing resin cements over a period of 3 years. METHODS: Ten bovine dentin specimens were tested for tensile bond strengths with each of the following materials: Super Bond C&B: unfilled methyl methacrylate (MMA)/polymethyl methacrylate (PMMA) resin cement, MASA Bond (experimental material): filled dimethacrylate resin cement at 1 day, 6 months, 1 and 3 years. The mean bond strengths were compared statistically by two-way ANOVA and Fisher's PLSD test (P<0.05). The mode of failure was classified by SEM observation. Results for the mode of fracture were analyzed using the Mann-Whitney U test. RESULTS: Although there was no statistical difference in mean bond strength between Super Bond C&B and MASA Bond (P>0.05) during the experimental periods, the 1-day bond strengths were significantly greater than those at the other experimental periods except for 6 months (P<0.05). Regarding the fracture modes, at 6 months and 1 year, statistical differences were observed between Super Bond C&B and MASA Bond (P<0.05). SIGNIFICANCE: The bond strengths of both resin cements to dentin significantly decreased after 6 months, and the long-term failure patterns of the 4-META/TBB resin cements showed a marked change.

Aminosalicylic Acids↗

PubMed2002

Morphological study of demineralized dentine after caries removal using two different methods.

BACKGROUND: Caries-affected dentine is the usual substrate bonded to in everyday clinical practice. The first step for most of the current dentine adhesive systems is etching or conditioning. It is therefore important to understand the effect of etchant/conditioner on caries-affected dentine. METHODS: Twelve extracted carious permanent molars were examined. Six teeth had caries removed using burs after staining with a caries detector dye, and caries from the other six was removed using Carisolv. After caries removal, three teeth from each group were left untreated. The remaining teeth were sectioned to obtain two normal dentine samples and two caries-affected dentine samples from each tooth. One half of the normal dentine samples and one half of the caries-affected dentine samples were treated with 35 per cent phosphoric acid, and the remaining samples were treated with 20 per cent polyacrylic acid/3 per cent aluminium chloride. The samples were observed using field emission scanning electron microscopy (FE-SEM). RESULTS: Phosphoric acid treated samples showed more obvious intertubular dentine microporosity and greater depth of demineralization in caries-affected dentine. Polyacrylic acid treated samples showed some residual smear layer. However, the peritubular and intertubular collagen network was easily observed in Carisolv treated dentine. The depth of demineralization was not as distinct as that of the phosphoric treated samples. CONCLUSIONS: From this study it was shown that etched 'normal' dentine and etched caries-affected dentine had different surface appearances. Furthermore, the two caries removal techniques resulted in different caries-affected dentine surfaces after acid treatment that may influence the longevity of bonds from adhesive restorative materials.

Acid Etching, Dental↗