Abstracts of the General Sessions of the Japanese Society for Dental Materials and Devices 50th General Session of the Japanese Society for Dental Materials and Devices in conjunction with International Dental Materials Congress 2007, 2007
Molar incisor hypomineralization (MIH) involves enamel hypomineralization of systemic origin affe... more Molar incisor hypomineralization (MIH) involves enamel hypomineralization of systemic origin affecting one or more first permanent molars (FPM) and is often associated with other teeth, particularly the incisors. A challenging condition for both the clinician and the patient, MIH affected teeth are often subjected to repeated treatments and frequently the decision to extract one or more FPM is made. At present, there are no clinical reports of available restorative materials that are able to provide consistently adequate restorations on hypomineralized teeth. The concept of resin infiltration, which involves occluding incipient enamel carious lesions with low viscosity resins to arrest or slow the development of caries has the potential to be applied to hypomineralized enamel. Successful penetration of resin infiltrant into MIH affected enamel may aid in improving its micromechanical properties.
Journal of The Mechanical Behavior of Biomedical Materials, Sep 1, 2021
The objectives of this study were to evaluate 4 aspects of ion-leaching restorative materials (IL... more The objectives of this study were to evaluate 4 aspects of ion-leaching restorative materials (ILMs): 4-point bending flexural strength (4 PB-FS) and relative mechanical properties; biaxial flexural strength (B-FS) in relation to 4 PB-FS; porosity; and surface morphology. Eleven ILMs were used for the 4-point bending test. Bar-shaped (n = 15) samples were fabricated, stored in distilled water for 7 days. Then 4 PB-FS and the other mechanical properties were determined. Five ILMs were selected for the B-FS test using disk specimens (n = 15). The correlation between 4 PB-FS and B-FS was addressed. After the 4 PB test, 5 randomised fragments from each material were used to make 0.5 mm-thick sections for light microscopy to investigate the degree of porosity using reflected and transmitted lights. Eight ILMs were selected for quantitative analysis of the fractional % pore volume (PV%) due to their relative pore prominence using ImageJ software. One-way ANOVA/Dunnett's T3 was used to test for significance. Resin-based ILMs (RB-ILMs) were ranked first (p < 0.05) for 4 PB-FS values (53.3-110.2 MPa) followed by resin-modified glass-ionomer cements (RMGICs; 30.9-44.3 MPa) and high-viscosity glass-ionomer cements (HVGICs; 12.9-19.6 MPa), respectively. 'Flexural modulus' (4 PB-E) and 'flexural toughness' (4 PB-T) of ILMs varied even though similar 4 PB-FS values were observed. There was a positive correlation (p < 0.001) between 4PB-FS and B-FS (R2 = 0.992) with B-FS>4 PB-FS. There was no correlation between PV% and 4 PB-FS. In summary, material type played a major role in 4 PB-FS outcomes, whereas PV% seemed to have a minor effect when evaluating each material group of ILMs. Brittleness/ductility of ILMs was observed when determining 4 PB-E and 4 PB-T relative to 4 PB-FS. When selecting materials for posterior load-bearing dental restorations in high-caries risk patients, RB-ILMs or RMGICs would be more appropriate due to their superior flexural properties compared with recently introduced HVGICs. The decision for each situation will also be dependent on further evidence of the ion-leaching capacity.
BackgroundThis study compared natural root caries lesions with artificial root caries lesions pre... more BackgroundThis study compared natural root caries lesions with artificial root caries lesions prepared with one of the two demineralising solutions.MethodsTwelve natural root caries lesions on upper incisors and 24 artificial root lesions were prepared on sound root surfaces using 50 mM acetic acid, 1.5 mM CaCl2, 0.9 mM KH2PO4 at pH 5.0 or 80 mL/L Noverite K‐702 polyacrylate solution, 500 mg/L hydroxyapatite, 0.1 mol/L lactic acid at pH 4.8 (n = 12/group) for 96 hours. Lesions were scanned using micro‐CT. Inciso‐gingival oriented images were analysed and mineral density calculated at 7.5 μm increments from the surface to 225‐μm deep. Sectioned lesions were analysed by Knoop microhardness up to 250 μm from the lesion surface. Data were analysed by the Dunn's test with Bonferroni correction.ResultsNatural and artificial lesion mean mineral densities were not statistically different (P &gt; 0.05). Mineral density from the surface to 75 μm was greater in natural lesions and from 150 to 225 μm was greater in artificial lesions (P &lt; 0.05). Microhardness values were statistically higher in artificial lesions (P &lt; 0.05); no difference was found among artificial lesions produced by the two solutions (P &gt; 0.05). Mineral density and microhardness of natural and artificial root caries are different from each other. A greater mineralized surface layer existed on natural lesions.
SUMMARY Objectives: This study investigated cuspal deformation in teeth restored with different t... more SUMMARY Objectives: This study investigated cuspal deformation in teeth restored with different types of adhesive materials with and without a base. Methods: Mesio-occluso-distal slot cavities of moderately large dimension were prepared on extracted maxillary premolars (n=24). Teeth were assigned to one of four groups and restored with either a sonic-activated bulk-fill resin composite (RC) (SonicFill), or a conventional nanohybrid RC (Herculite Ultra). The base materials used were a flowable nanofilled RC (Premise Flowable) and a high-viscosity resin-modified glass-ionomer cement (RMGIC) (Riva Light-Cure HV). Cuspal deflection was measured with two direct current differential transformers, each contacting a buccal and palatal cusp. Cuspal movements were recorded during and after restoration placement. Data for the buccal and palatal cusp deflections were combined to give the net cuspal deflection. Results: Data varied widely. All teeth experienced net inward cuspal movement. No statistically significant differences in cuspal deflection were found among the four test groups. Conclusions: The use of a flowable RC or an RMGIC in closed-laminate restorations produced the same degree of cuspal movement as restorations filled with only a conventional nanohybrid or bulk-fill RC.
BackgroundThis study evaluated the ability of a CPP‐ACP‐modified Glass–ionomer cement (GIC) to in... more BackgroundThis study evaluated the ability of a CPP‐ACP‐modified Glass–ionomer cement (GIC) to inhibit demineralization around the margins of cervical cavities in natural teeth in comparison with a Giomer and conventional GIC with and without coating.MethodsThirty‐two sound human molars were used. Box‐shaped cavities were prepared along the CEJ. Teeth were randomly divided into four groups and restored with Equia Forte Fil, Coated Equia Forte Fil, Fuji VII EP or Beautifil II. Teeth were subjected to pH cycling. Micromorphological and elemental analyses were done using SEM and EDX. Polarized light microscope analysis and microhardness tests were also performed.ResultsMicrohardness tests on enamel showed a significant difference between the coated Equia group, Equia and Beautifil II groups (P < 0.05). Dentine results showed significant differences between the coated Equia group and all other groups (P < 0.05). Elemental analysis showed significant differences in calcium weight p...
Abstracts of the General Sessions of the Japanese Society for Dental Materials and Devices 50th General Session of the Japanese Society for Dental Materials and Devices in conjunction with International Dental Materials Congress 2007, 2007
Molar incisor hypomineralization (MIH) involves enamel hypomineralization of systemic origin affe... more Molar incisor hypomineralization (MIH) involves enamel hypomineralization of systemic origin affecting one or more first permanent molars (FPM) and is often associated with other teeth, particularly the incisors. A challenging condition for both the clinician and the patient, MIH affected teeth are often subjected to repeated treatments and frequently the decision to extract one or more FPM is made. At present, there are no clinical reports of available restorative materials that are able to provide consistently adequate restorations on hypomineralized teeth. The concept of resin infiltration, which involves occluding incipient enamel carious lesions with low viscosity resins to arrest or slow the development of caries has the potential to be applied to hypomineralized enamel. Successful penetration of resin infiltrant into MIH affected enamel may aid in improving its micromechanical properties.
Journal of The Mechanical Behavior of Biomedical Materials, Sep 1, 2021
The objectives of this study were to evaluate 4 aspects of ion-leaching restorative materials (IL... more The objectives of this study were to evaluate 4 aspects of ion-leaching restorative materials (ILMs): 4-point bending flexural strength (4 PB-FS) and relative mechanical properties; biaxial flexural strength (B-FS) in relation to 4 PB-FS; porosity; and surface morphology. Eleven ILMs were used for the 4-point bending test. Bar-shaped (n = 15) samples were fabricated, stored in distilled water for 7 days. Then 4 PB-FS and the other mechanical properties were determined. Five ILMs were selected for the B-FS test using disk specimens (n = 15). The correlation between 4 PB-FS and B-FS was addressed. After the 4 PB test, 5 randomised fragments from each material were used to make 0.5 mm-thick sections for light microscopy to investigate the degree of porosity using reflected and transmitted lights. Eight ILMs were selected for quantitative analysis of the fractional % pore volume (PV%) due to their relative pore prominence using ImageJ software. One-way ANOVA/Dunnett's T3 was used to test for significance. Resin-based ILMs (RB-ILMs) were ranked first (p < 0.05) for 4 PB-FS values (53.3-110.2 MPa) followed by resin-modified glass-ionomer cements (RMGICs; 30.9-44.3 MPa) and high-viscosity glass-ionomer cements (HVGICs; 12.9-19.6 MPa), respectively. 'Flexural modulus' (4 PB-E) and 'flexural toughness' (4 PB-T) of ILMs varied even though similar 4 PB-FS values were observed. There was a positive correlation (p < 0.001) between 4PB-FS and B-FS (R2 = 0.992) with B-FS>4 PB-FS. There was no correlation between PV% and 4 PB-FS. In summary, material type played a major role in 4 PB-FS outcomes, whereas PV% seemed to have a minor effect when evaluating each material group of ILMs. Brittleness/ductility of ILMs was observed when determining 4 PB-E and 4 PB-T relative to 4 PB-FS. When selecting materials for posterior load-bearing dental restorations in high-caries risk patients, RB-ILMs or RMGICs would be more appropriate due to their superior flexural properties compared with recently introduced HVGICs. The decision for each situation will also be dependent on further evidence of the ion-leaching capacity.
BackgroundThis study compared natural root caries lesions with artificial root caries lesions pre... more BackgroundThis study compared natural root caries lesions with artificial root caries lesions prepared with one of the two demineralising solutions.MethodsTwelve natural root caries lesions on upper incisors and 24 artificial root lesions were prepared on sound root surfaces using 50 mM acetic acid, 1.5 mM CaCl2, 0.9 mM KH2PO4 at pH 5.0 or 80 mL/L Noverite K‐702 polyacrylate solution, 500 mg/L hydroxyapatite, 0.1 mol/L lactic acid at pH 4.8 (n = 12/group) for 96 hours. Lesions were scanned using micro‐CT. Inciso‐gingival oriented images were analysed and mineral density calculated at 7.5 μm increments from the surface to 225‐μm deep. Sectioned lesions were analysed by Knoop microhardness up to 250 μm from the lesion surface. Data were analysed by the Dunn's test with Bonferroni correction.ResultsNatural and artificial lesion mean mineral densities were not statistically different (P &gt; 0.05). Mineral density from the surface to 75 μm was greater in natural lesions and from 150 to 225 μm was greater in artificial lesions (P &lt; 0.05). Microhardness values were statistically higher in artificial lesions (P &lt; 0.05); no difference was found among artificial lesions produced by the two solutions (P &gt; 0.05). Mineral density and microhardness of natural and artificial root caries are different from each other. A greater mineralized surface layer existed on natural lesions.
SUMMARY Objectives: This study investigated cuspal deformation in teeth restored with different t... more SUMMARY Objectives: This study investigated cuspal deformation in teeth restored with different types of adhesive materials with and without a base. Methods: Mesio-occluso-distal slot cavities of moderately large dimension were prepared on extracted maxillary premolars (n=24). Teeth were assigned to one of four groups and restored with either a sonic-activated bulk-fill resin composite (RC) (SonicFill), or a conventional nanohybrid RC (Herculite Ultra). The base materials used were a flowable nanofilled RC (Premise Flowable) and a high-viscosity resin-modified glass-ionomer cement (RMGIC) (Riva Light-Cure HV). Cuspal deflection was measured with two direct current differential transformers, each contacting a buccal and palatal cusp. Cuspal movements were recorded during and after restoration placement. Data for the buccal and palatal cusp deflections were combined to give the net cuspal deflection. Results: Data varied widely. All teeth experienced net inward cuspal movement. No statistically significant differences in cuspal deflection were found among the four test groups. Conclusions: The use of a flowable RC or an RMGIC in closed-laminate restorations produced the same degree of cuspal movement as restorations filled with only a conventional nanohybrid or bulk-fill RC.
BackgroundThis study evaluated the ability of a CPP‐ACP‐modified Glass–ionomer cement (GIC) to in... more BackgroundThis study evaluated the ability of a CPP‐ACP‐modified Glass–ionomer cement (GIC) to inhibit demineralization around the margins of cervical cavities in natural teeth in comparison with a Giomer and conventional GIC with and without coating.MethodsThirty‐two sound human molars were used. Box‐shaped cavities were prepared along the CEJ. Teeth were randomly divided into four groups and restored with Equia Forte Fil, Coated Equia Forte Fil, Fuji VII EP or Beautifil II. Teeth were subjected to pH cycling. Micromorphological and elemental analyses were done using SEM and EDX. Polarized light microscope analysis and microhardness tests were also performed.ResultsMicrohardness tests on enamel showed a significant difference between the coated Equia group, Equia and Beautifil II groups (P < 0.05). Dentine results showed significant differences between the coated Equia group and all other groups (P < 0.05). Elemental analysis showed significant differences in calcium weight p...
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