Growth factor release and dental pulp stem cell attachment following dentine conditioning: An in vitro study.

AIM: The aim of the study was to investigate the effect of dentine conditioning agents on growth factor liberation and settlement of dental pulp progenitor cells (DPSCs) on dentine surfaces. METHODOLOGY: The agents used included ethylenediaminetetraacetic acid (EDTA; 10%, pH 7.2), phosphoric acid (37%, pH < 1), citric acid (10%, pH 1.5) and polyacrylic acid (25%, pH 3.9). Human dentine slices were conditioned for exaggerated conditioning times of 5 and 10 min, so that the growth factor liberation reached quantifiable levels above the limit of detection of the laboratory methods employed. Transforming growth factor beta-1 (TGF-ß1) release and surface exposure were quantified by enzyme-linked immunosorbent assay (ELISA) and immunogold labelling. Scanning electron microscopy (SEM) was used to assess the morphology of cells and coverage by DPSCs cultured on dentine surfaces for 8 days. RESULTS: After 5-min conditioning of dentine slices, citric acid was the most effective agent for growth factor release into the aqueous environment as measured by ELISA (Mann-Whitney U with Bonferroni correction, p < .01 compared with phosphoric and polyacrylic acid). As well as this, dentine slices treated with phosphoric acid for the same period, displayed significantly less TGF-ß1 on the surface compared with the other agents used, as measured by immunogold labelling (MWU with Bonferroni correction, p < .05). After 8 days, widespread coverage by DPSCs on dentine surfaces conditioned with citric acid and EDTA were evident under SEM. On dentine surfaces conditioned with phosphoric and polyacrylic acid, respectively, less spread cells and inconsistent cell coverage were observed. CONCLUSIONS: Based on the findings of this in vitro study, a desirable biological growth factor-mediated effect may be gained when conditioning dentine by milder acidic or chelating agents such as citric acid and EDTA. The results must be interpreted in the context that the potential of the applied materials inducing a desirable biological response in DPSCs is only one consideration amongst other important ones in a clinical setting. However, it is crucial to look beyond the mere physical effects of materials and move towards biologically based treatment approaches as far as the restorative management of teeth with viable dental pulps are concerned.

Effects of storage media on physical properties of selected tooth coloured restorative materials.

It is known that storage media can affect the physical properties of some restorative dental materials. The purpose of this laboratory study was to investigate the possible effects of storage media on physical properties of a conventional glass-ionomer, a resin modified glass ionomer and a compomer. Specimens of the restorative materials in the study (FujiII LC, FujiIX and Dyract EXTRA) were prepared. The specimens were stored in either water or artificial saliva with or without exposure to Listerine. The compressive and diametral tensile strength and Vickers hardness of these materials were tested at 24 hours, 1 week, 4 weeks and 12 weeks. Compressive and diametral tensile strength for FujiII LC and Fuji IX had increased at 12 weeks. A decrease was observed for Dyract EXTRA in the same period. No significant differences were observed between the storage media (P > 0.01). Vickers hardness values fluctuated during the testing period, with a pattern being consistent for each material. Storage of materials investigated for the period in this study resulted in superior compressive and diametral tensile strength for Fuji II LC and FujiIX. The opposite was true for Dyract EXTRA. Effects of time were found to be more pronounced than the media (P < 0.01).

Effect of selected mouthwashes with and without toothbrushing on the surface hardness of a resin modified glass-ionomer and two compomers.

OBJECTIVES: Physical properties of some restorative dental materials can change as a result of exposure to mouthwashes and toothbrushing. The purpose of this laboratory study was to investigate the possible effects of three commercially available mouthwashes on the surface hardness and weight of a resin modified glass-ionomer and two compomers when used with and without tooth brushing. METHODS: Specimens of the restorative materials in the study (Vitremer, Compoglass and Dyract) were prepared. Half of the specimens were only exposed to a mouthwash (Plax, Macleans, Listerine, Corsodyl or deionised water as control). The remaining specimens were exposed to one of the mouthwashes in conjunction with tooth brushing. The initial surface hardness and the surface hardness after 24 weeks were assessed using a Wallace hardness testing instrument. The specimens were assessed for possible weight changes between baseline and 24 weeks using a digital balance. RESULTS: Mouthwash only: The Wallace hardness values of Vitremer and Compoglass increased in all groups. For Vitremer the increase was significantly higher in Macleans group in comparison with the control, Listerine and Corsodyl groups (P<0.05). For Compoglass the increase in Plax and Macleans groups were significantly higher compared with the control group (P<0.05). Dyract specimens revealed an increase in Wallace hardness values in all test groups whilst the control group revealed a decrease (P<0.05 except for Plax). Mouthwash and toothbrushing. Wallace hardness for all materials increased. The difference was not significant between groups (P>0.05). Weighing the specimens of Vitremer revealed that after 24 weeks exposure to mouthwash and toothbrushing some groups had lost weight while an increase in weight was observed in others (P>0.05). For Compoglass and Dyract, all groups had lost weight after 24 weeks (P>0.05). SIGNIFICANCE: Exposure of the materials investigated in this study to the mouthwashes and toothbrushing had adverse effects on surface hardness. The adverse effects were more apparent when the mouthwashes were used alone.

Effect of selected mouthwashes on the surface roughness of resin modified glass-ionomer restorative materials.

OBJECTIVES: It is known that the use of mouthwashes and toothbrushing can affect some restorative dental materials. The purpose of this laboratory study was to investigate the effect of four commercially available mouthwashes on the surface roughness of a number of resin modified glass-ionomer restorative materials when used with and without tooth brushing. METHODS: Specimens of the restorative materials in the study (Vitremer, Compoglass and Dyract) were prepared. Half of the specimens were only exposed to a mouthwash (Plax, Macleans, Listerine, Corsodyl or deionised water as control). The remaining specimens were exposed to one of the mouthwashes in conjunction with tooth brushing. The initial surface roughness and the subsequent changes in surface roughness were assessed by scanning electron microscopy (SEM) and profilometry. The assessment times were: baseline, 4, 12 and 24 weeks. RESULTS: Initial SEM observations of the surface morphology of the specimens revealed a rougher surface for Vitremer in comparison to the other two materials. Assessments at increasing time intervals showed that specimens exposed to a mouthwash only appeared to become rougher. The appearance of specimens exposed to mouthwash and brushing seemed to become even rougher with increasing time. The results of the profilometric assessment showed that at 24 weeks, specimens exposed to mouthwash only, had an overall increase in the surface roughness values for all three materials investigated. The differences between groups allocated to different mouthwashes were not however statistically significant (P>0.05). Exposure to mouthwash and toothbrushing over the same time period resulted in an increase in roughness values in all groups. The differences between mouthwash groups were not statistically significant at this stage (P>0.05). SIGNIFICANCE: Exposure of the materials investigated to the mouthwashes included in the study had adverse effects on surface roughness. The adverse effects were more pronounced with tooth brushing.

The erosive potential of some flavoured waters.

OBJECTIVES: To assess the erosive potential of a number of readily available flavoured waters in the laboratory. METHODS: The erosive potential was assessed by measuring the pH, neutralisable acidity and ability to erode enamel. These were compared to an orange juice positive control. RESULTS: The pH of the flavoured waters ranged from 2.64-3.24 with their neutralisable acidity ranging from 4.16-16.30 mls of 0.1M NaOH. The amount of enamel removed following 1-hour immersion in the drinks ranged from 1.18-6.86 microns. In comparison, the orange juice control had a pH of 3.68, a neutralisable acidity of 19.68 mls of 0.1 M NaOH and removed 3.24 microns of enamel. CONCLUSIONS: Many of the flavoured waters tested were found to be as erosive as orange juice. This information will be of use to clinicians when counselling patients with tooth surface loss. (Eur J Dent 2007;1:5-9).

Adverse reaction to prophylactic amoxicillin: a case report.

Antibiotic prophylaxis is required prior to invasive dental procedures for those patients at risk of bacterial endocarditis. The clinician should be aware of the possibility of allergic reaction to the antibiotics and be prepared for the medical management of the symptoms. This paper presents a case of an allergic reaction to prophylactic amoxicillin administered orally to a patient prior to dental treatment.