A resin-modified glass-ionomer cement (RMGIC) was studied from a computational point of view. We suggest terpolymer formation by reaction of fixation through a combination of acrylic acid (AA), itaconic acid (IA) and ...A resin-modified glass-ionomer cement (RMGIC) was studied from a computational point of view. We suggest terpolymer formation by reaction of fixation through a combination of acrylic acid (AA), itaconic acid (IA) and an aminoacid derivative (AAD) in different positions. We found that AAD-AA-IA is thermodynamically more stable, but AA-IA-AAD is the combination which can react with glycidyl methacrylate (GM) to form a grafted polymer with two pendant methacrylate groups which can be used later in the process of light-curing. A RMGIC contains a glass powder of calcium-fluoroaluminosilicate acting as the source of cross linking, and for this reason, we have optimized two intramolecular Al3+ tricarboxylate complexes (salt-bridges) formed from the most stable grafted polymers. A possible reaction mechanism for the addition of (GM) to copolymer is proposed.展开更多
The purpose of this study was to compare the sealing ability and marginal adaptation of four re-storative materials (MTA, Biodentine, portlant cement, and resin modified glass ionomer cement) used to repair iatrogenic...The purpose of this study was to compare the sealing ability and marginal adaptation of four re-storative materials (MTA, Biodentine, portlant cement, and resin modified glass ionomer cement) used to repair iatrogenic furcation perforations. Eighty-four molars were treated endodontically, perforated in the middle of the pulp chamber floor with a round bur and separated randomly into 4 groups of 20 teeth each, while 4 teeth were used as positive and negative controls. The teeth were embedded in a moistened flower sponge and the perforations were filled with the appropriate restorative materials: Group 1: Biodentine;Group 2: MTA Angelus;Group 3: GC Fuji lining LC Paste Pak;Group 4: Aquafix Portland cement. The teeth remained in the soaked sponge for 28 days and then were submerged in basic fuchsine solution 1% for 48 hours. Dye penetration was evaluated after longitudinal sectioning of the teeth. Statistical analysis revealed that perforations restored with MTA exhibited the least microleakage with statistically significant difference among the other three groups (p < 0.05). The worst sealing ability was observed in the teeth restored with Aquafix Portland cement. No statistically significant difference was found between the groups of Biodentine and FC Fuji Lining Paste (p = 0.066).展开更多
To evaluate the retention properties of the novel ‘C＇-shaped molar bands at a laboratory level. Resin-modified glass ionomer cement（RMGIC） was used as a luting agent for the novel C-shaped molar band. The mechanic...To evaluate the retention properties of the novel ‘C＇-shaped molar bands at a laboratory level. Resin-modified glass ionomer cement（RMGIC） was used as a luting agent for the novel C-shaped molar band. The mechanical properties of the band were examined and the retention performance was characterized in the mesial, distal and vertical directions. A clinical trial was conducted using a spilt-mouth design on 50 patients. The novel C-shaped molar bands fit most molars without a repeated try-in process.The use of both nanoHA coating and RMGIC enhanced the tensile（8.00 ± 1.8 MPa） and shear strengths（27.17 ± 8.6 MPa） of the molar bands, leading to high retention in vertical, mesial and distal directions（ p 〈 0.001）. In clinical trials, the C-shaped molar bands had a failure rate（15%） comparable to that of traditional bands, and 93% of the failed bands demonstrated an adhesive remnant index score of 0, corroborating the observation that no luting agent residue remained on the tooth surface in most cases. The novel C-shaped molar bands appear to be a promising appliance that requires further clinical investigations, and may be used effectively in orthodontics.展开更多
文摘A resin-modified glass-ionomer cement (RMGIC) was studied from a computational point of view. We suggest terpolymer formation by reaction of fixation through a combination of acrylic acid (AA), itaconic acid (IA) and an aminoacid derivative (AAD) in different positions. We found that AAD-AA-IA is thermodynamically more stable, but AA-IA-AAD is the combination which can react with glycidyl methacrylate (GM) to form a grafted polymer with two pendant methacrylate groups which can be used later in the process of light-curing. A RMGIC contains a glass powder of calcium-fluoroaluminosilicate acting as the source of cross linking, and for this reason, we have optimized two intramolecular Al3+ tricarboxylate complexes (salt-bridges) formed from the most stable grafted polymers. A possible reaction mechanism for the addition of (GM) to copolymer is proposed.
文摘The purpose of this study was to compare the sealing ability and marginal adaptation of four re-storative materials (MTA, Biodentine, portlant cement, and resin modified glass ionomer cement) used to repair iatrogenic furcation perforations. Eighty-four molars were treated endodontically, perforated in the middle of the pulp chamber floor with a round bur and separated randomly into 4 groups of 20 teeth each, while 4 teeth were used as positive and negative controls. The teeth were embedded in a moistened flower sponge and the perforations were filled with the appropriate restorative materials: Group 1: Biodentine;Group 2: MTA Angelus;Group 3: GC Fuji lining LC Paste Pak;Group 4: Aquafix Portland cement. The teeth remained in the soaked sponge for 28 days and then were submerged in basic fuchsine solution 1% for 48 hours. Dye penetration was evaluated after longitudinal sectioning of the teeth. Statistical analysis revealed that perforations restored with MTA exhibited the least microleakage with statistically significant difference among the other three groups (p < 0.05). The worst sealing ability was observed in the teeth restored with Aquafix Portland cement. No statistically significant difference was found between the groups of Biodentine and FC Fuji Lining Paste (p = 0.066).
基金Funded by Department of Education,National Natural Science Foundation of China(No.81170960)Heilongjiang Province(No.11531204)+1 种基金Department of Health,Heilongjiang Province(No.2006-123)Youth Foundation of the Second Affiliated Hospital of Harbin Medical University(No.QN2006-13)
文摘To evaluate the retention properties of the novel ‘C＇-shaped molar bands at a laboratory level. Resin-modified glass ionomer cement（RMGIC） was used as a luting agent for the novel C-shaped molar band. The mechanical properties of the band were examined and the retention performance was characterized in the mesial, distal and vertical directions. A clinical trial was conducted using a spilt-mouth design on 50 patients. The novel C-shaped molar bands fit most molars without a repeated try-in process.The use of both nanoHA coating and RMGIC enhanced the tensile（8.00 ± 1.8 MPa） and shear strengths（27.17 ± 8.6 MPa） of the molar bands, leading to high retention in vertical, mesial and distal directions（ p 〈 0.001）. In clinical trials, the C-shaped molar bands had a failure rate（15%） comparable to that of traditional bands, and 93% of the failed bands demonstrated an adhesive remnant index score of 0, corroborating the observation that no luting agent residue remained on the tooth surface in most cases. The novel C-shaped molar bands appear to be a promising appliance that requires further clinical investigations, and may be used effectively in orthodontics.
