Self-cured Glass Ionomer Cement Research Articles

Self-Curing Glass Ionomer Cement Covered by Photopolymerizable Adhesive for Protection of Mucoperiosteal or Gingival Flap Sutures in Canine Oral Surgery.

Periodontal disease is one of the main affections of the oral cavity of dogs. Its main complication is the formation of periapical abscess, which, when affecting the maxillary canine teeth, can lead to the formation of oronasal fistulae. The objective of this study was to evaluate the efficiency of self-curing glass ionomer cement, covered by photopolymerizable adhesive, as a protective element for mucoperiosteal or gingival flap sutures in oral surgery of dogs. We studied 15 dogs from the clinical routine of the dental service of a teaching veterinary hospital, which needed oral surgeries to correct oronasal fistulae, defects or oral cavity communications, regardless of the causal agent. Group one (G1) was composed of seven animals that presented oronasal fistulae after the extraction of maxillary canine teeth compromised by severe periodontal disease. These fistulae were reduced by the double-mucoperiosteal-flap technique, 15 days after the dental extraction. Group two (G2) was composed of five other dogs that presented oronasal fistulae after the extraction of maxillary canine teeth compromised by severe periodontal disease. In this group, the fistulae were reduced by the single-flap technique, immediately after the dental extraction. Group three (G3) was composed of three animals, two of which presented oronasal fistulae due to maxillary fracture and the third one after excision of oral neoplasia. In all groups, simple interrupted sutures were used with 3.0 nylon, and a thin layer of self-curing glass ionomer cement was applied immediately over the operated area. After cement's settling time, a thin layer of photopolymerizable adhesive was applied to the already polymerized cement. In G1, the protective cement was removed on average at 15 (±2) postoperative days, in G2 at 6 (±1) days and in G3 at 11 (±9) days. In the postoperative period, the animals received antibiotics and anti-inflammatory drugs, and they received their usual dry dog food diet. No Elizabethan collar or any other protective measure was used for suturing or the surgical wound. The result was healing of 100% of the oronasal fistulae, without suture dehiscence or the need for new surgical interventions. Thus, it was concluded that the use of self-curing glass ionomer cement covered by photopolymerizable adhesive was fully satisfactory, providing protection of sutures and surgical wounds and showing the potential for routine use in oral surgery in dogs.

A comparative evaluation of microleakage and dentin shear bond strength of three restorative materials

Aim To evaluate the microleakage and dentin shear bond strength of two glass containing restorative materials, Zirconomer and Cention N, and to compare them with a conventional glass ionomer cement (GIC) (GC Fuji II). Materials and methods Zirconomer (Shofu) and GC Fuji II (GC Corp.) are self-curing GICs whereas Cention N (IvoclarVivadent) also offers a self-curing option as well as the option of light-curing using an adhesive. For evaluating microleakage, standardized class V cavities were prepared on the buccal surface of 30 premolars. The cavities were restored with one of the three restorative materials (n = 10) according to manufacturers’ instructions, Cention N being used with an adhesive (Te-EconomBond, IvoclarVivadent) and in the light-curing mode. After restoration and thermocycling, the microleakage assessment was made under a stereomicroscope at 40x magnification following immersing of the teeth in 0.5% methylene blue dye and buccolingual sectioning. For evaluating dentin shear bond strength, the occlusal surface of the 30 premolars was ground flat, and cylinders of the three restorative materials (n = 10) were bonded to the occlusal surface according to manufacturers’ instructions, Cention N being used with an adhesive (Te-EconomBond, IvoclarVivadent) and in the light-curing mode. Following 24-h storage at 100% humidity, the dentin shear bond strength was measured and the fracture mode was determined under a stereomicroscope at 10× magnification. Data were statistically analyzed using Mann–Whitney and Scheffé tests (p = .05). Results Cention N displayed significantly less microleakage than did Zirconomer and GC Fuji II at occlusal as well as the gingival margins. Dentin shear bond strength varied significantly between 5.15 and 9.89 MPa with Cention N showing the highest bond strength and GC Fuji II the lowest. Conclusion In this in vitro evaluation, Cention N consistently performed better than the conventional GIC (GC Fuji II) as well as Zirconomer.

Histological evaluation of the synergistic effect of chitosan and mineral trioxide aggregate on mechanically exposed dental pulp following pulp capping in dogs' teeth

Introduction: This work studied the synergistic effect of chitosan and mineral trioxide aggregate (MTA) on mechanically exposed dental pulp following pulp capping in dogs' teeth.Materials and Methods: Class V cavities were prepared in 60 teeth of 3 mongrel dogs. These cavities were prepared approximately 1 mm coronal to the gingival margin by using a round carbide bur #2 with water cooling. These teeth were divided according to the pulp capping material into 2 groups (30 teeth each); Group I: MTA and Group II: a combination of MTA and chitosan compound. The cavities were restored by self-curing glass ionomer cement, followed by varnish application to provide the suitable conditions for pulpal repair. Both groups were further subdivided according to the evaluation period into 3 subgroups (10 teeth each); subgroup A: 7 days, subgroup B: 21 days, and subgroup C: 60 days. Histological evaluation of dentin bridge formation was performed after pulp capping in all subgroups. Data were statistically analyzed by ANOVA, Tukey's post hoc, Kruskal–Wallis, and Mann–Whitney U-tests. The significance level was set at P ≤ 0.05.Results: No statistically significant difference was found between both groups at all evaluation times (P > 0.05). The combination of MTA and chitosan did not improve the quality of dentin bridge produced by the MTA alone.Conclusion: Mixing of chitosan and MTA as a direct pulp capping material has no synergistic odontogenic effect in dog's teeth.

Reconstruction of Pulpotomized Primary Molar and Retention of Stainless-steel Crowns: An In-vitro Study

Background: Stainless steel crowns are proposed to restore severely decayed teeth in pediatric dentistry. Yet, their retention is still debatable. Objective: This study aimed to investigate whether dental tissue reconstruction before placement of stainless steel crown on pulpotomized first primary molar affects the retention of stainless steel crowns. Methods: This experimental in-vitro study was performed on 30 extracted first primary molars with carious occlusal and distal surfaces. Dental caries and the pulp chamber roof were respectively removed. The stainless steel crowns were placed after tooth preparation. The samples were randomly divided into two groups (n=15) i.e, ZoE core buildup, and ZoE liner. Stainless steel crowns were cemented with self-curing glass ionomer cement. The crown retention was tested with the Instron testing machine. The two groups were compared by using SPSS software through the t-test (α=0.05). Results: The mean crown retention in the liner group (291.45±43.196 N) was significantly higher than that of the core buildup group (202.00±63.515 N) (P=0.001). Conclusion: Based on the results of this study for restoring the teeth with extensive tissue loss by SSC, ZoE should be used as lining without a core on teeth.

A self-cured glass-ionomer cement with improved antibacterial function and hardness.

A novel antimicrobial dental self-cured glass-ionomer cement has been developed and evaluated. Alumina filler particles were covalently coated with an antibacterial polymer and blended into a self-cured glass-ionomer cement formulation. Surface hardness and bacterial viability were used to evaluate the modified cements. Results showed that the modified cements exhibited a significantly enhanced antibacterial activity along with improved surface hardness. Effects of antibacterial moiety content, alumina particle size and loading, and total filler content were investigated. It was found that increasing antibacterial moiety content, particle size and loading, and total filler content generally increased surface hardness. Increasing antibacterial moiety, filler loading and total filler content increased antibacterial activity. On the other hand, increasing particle size showed a negative impact on antibacterial activity. The leaching tests indicate no cytotoxicity produced from the modified cements to both bacteria and 3T3 mouse fibroblast cells.

Fluoride Release and Uptake Capability of Glass-ionomer Cements and Compomers Used as Dental Restorative Materials

Dental caries and secondary caries are the most common problems in dentistry. Many studies provided evidence for the anticariogenic effect of fluorides. The incidence of secondary caries is decreased in teeth restored with fluoride releasing materials. The purpose of the present in vitro study is to evaluate the fluoride release and uptake capability of two glass-ionomer cements and two compomers. A total number of 60 specimens were prepared according to the manufacturer�s instructions using silicone molds. The specimens were transferred in plastic containers containing artificial saliva (pH=7), incubated at 37�C for 24 h and divided in three subgroups: control group, varnish treated group and dentifrice treated group. The fluoride ion content was measured on five times during a period of 30 days using an Orion 720A fluoride meter with 9609 BN fluoride ion electrode. The self-curing glass-ionomer cement released the highest amounts of fluoride ions at the beginning and after the one month study period. The samples of the four materials tested in the varnish treated groups showed significant differences compared to their control groups on the second day. Dentifrice treated groups did not show significant differences compared to their control groups, except values measured after 30 days. Application of fluoride varnish produced an increase of fluoride release for the first 24 h in case of all materials. However, results suggest that the use of fluoridated dentifrice would be more effective in caries prevention due to their fluoride uptake capability.

Antibacterial activity of glass ionomer cement modified by zinc oxide nanoparticles.

This study evaluated the antibacterial activity of zinc oxide nanoparticles incorporated into self-cured glass ionomer cement (GIC) and light-cured resin-reinforced GIC on Streptococcus mutans biofilm. The GICs, Fuji II (GC America) and Fuji II LC (GC America), were incorporated with nanoparticles at concentrations of 0%, 1%, and 2% by weight, and the biofilm maturation time was one and seven days. Circular specimens of each GIC type were prepared. The antibacterial activity was evaluated by determining the number of colony forming units of S. mutans strain per milliliter. Morphology of the biofilm was analyzed by scanning electron microscopy (SEM). The data obtained for each GIC were analyzed by two-way ANOVA (α = 5%). For chemically activated GIC, no significant difference was observed in relation to the time of biofilm maturation (p = 0.744), concentration of nanoparticles (p = 0.966), and their interaction (p = 0.800). The results from analysis of GIC modified by light-polymerized resin showed that only of the maturing time significantly affected the number of adhered cells on the biofilm (p = 0.034, F = 4.778). The more mature the biofilm, higher the number of cells. SEM analysis showed no change in cell morphology in relation to the type of GIC, maturation time, and nanoparticles concentration. We conclude that the inclusion of zinc oxide nanoparticles at concentrations of 1% and 2% by weight into the GICs evaluated here, did not promote their antimicrobial activity against S. mutans.

Evaluation of the mechanical properties of conventional glass ionomer cement after the addition of casein phosphopeptide amorphous calcium phosphate: An in vitro study

Background: Casein phosphopeptides-amorphous calcium phosphate (CPP-ACP) products have gained much importance in restorative dentistry and minimally invasive dentistry. Addition of CPP into glass ionomer cement (GIC) has been shown to interact with fluoride ions to produce an additive anticariogenic effect through the formation of stabilized amorphous calcium fluoride phosphate phase. Aim: The aim of this study was to determine the additive effect of CPP-ACP on the mechanical properties of conventional GIC. Materials and Methods: The control GIC was prepared with self-curing GIC. The GIC containing CPP-ACP was prepared from the same batch, with 1.56% w/w CPP-ACP incorporated. Compressive strength and microtensile bond strength tests were done. Energy dispersive X-ray (EDX) analysis was used to determine the composition of various structural phases. Results: Incorporation of 1.56% w/w CPP-ACP into the GIC resulted in an increase in compressive strength and microtensile bond strength. The representative EDX spectra taken showed enhanced release of calcium, phosphate, and fluoride ions.

A long-term study of apicoectomy and endodontic treatment of apically infected cheek teeth in 12 horses

The aim of this study was to evaluate the long-term results of apicoectomy and retrograde endodontic treatment in 12 horses with apical cheek teeth infections. The affected apices were removed using a diamond bur mounted on a dental drill, and after pulp removal the root canals were filed with Hedstrøm files and then alternately flushed with sodium hypochlorite, hydrogen peroxide and alcohol. The pulp canals were dried and filled with endodontic cement and gutta-percha points. An undercut was made in the apical aspect of the root canals that were then sealed with self-curing glass ionomer cement. Follow up information was obtained 38–67 months following treatment and indicated that the treatment had been successful in 7/12 horses (58%), partially successful in 2 horses (17%) and unsuccessful in 3 (25%). With good case selection, apicoectomy can preserve a proportion of apically infected cheek teeth. The use of advanced imaging techniques and improved surgical techniques could increase the success rate.

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.

Synthesis of amino acid-containing polyacids and their application in self-cured glass-ionomer cement

Six methacrylate or acrylate derivatives of natural amino acids were synthesized and characterized. Based upon these monomers, six terpolymers [poly(acrylic) acid-co-itaconic acid-co-amino acid] were prepared and characterized. The synthesized polymers were used to formulate glass-ionomer cements (GICs) using Fuji II glass filler. The effects of the molecular weight (MW) and powder/liquid ( P/ L) ratio were evaluated. Scanning electron microscopy (SEM) was used to examine the fracture surfaces of the selected cement specimens. Results show that all the amino acid modified GICs exhibited higher compressive strengths (CS, 193–236 MPa) and much higher flexural strengths (FS, 55–71 MPa) as compared to commercial Fuji II GIC (191 in CS and 16 in FS). Both MW and P/ L ratio affected the strength of the formed cement. It was important to find the optimal MW and P/ L ratio to obtain the highest FS. In this study, optimized MW (number average) of the polyacids and P/ L ratio were around 50,000 and 2.7/1, respectively. The microstructures of the fracture surfaces helped to explain the strength differences among the materials tested in the study. SEM analysis suggests that more integrated microstructures and fewer defects can lead to higher FS.

Antibacterial Activity of Restorative Dental Biomaterials in vitro

This study investigated the antibacterial effects against Streptococcus mutans of a fine-hybrid resin composite (FH-RC; Tetric ceram), an ion-releasing resin composite (Ariston pHc), a self-curing glass ionomer cement (SC-GIC; Ketac-Molar), a resin-modified GIC (RM-GIC; Photac-Fil), and a zinc oxide eugenol cement (ZOE; IRM). In a novel assay, bacterial suspensions were placed into narrow 20-µl conical cavities within the materials. After 0, 4, 8, 24, 48 h and 1 week of incubation, the suspensions were removed from the restoratives and the numbers of viable bacteria were determined. After incubation periods of 8 h or more, all restorative materials except the FH-RC showed significant growth inhibition when compared with controls. The strongest antibacterial activity was observed with ZOE. The inhibitory effect of Ariston pHc was similar to that of the SC-GIC and the RM-GIC. In the second assay, growth inhibition was evaluated in liquid cultures by incubating eluates of the materials with suspensions of S. mutans. Bacterial growth was determined up to 6 h by measuring absorption at 600 nm. The most marked inhibitory effect was again observed with ZOE. The SC-GIC caused a significant inhibition at all time intervals but the FH-RC, the RM-GIC and Ariston pHc exhibited no significant antibacterial effects. It is recommended to employ more than one method for assessing the antibacterial potential of restorative materials. Long-term clinical trials are necessary to determine whether the antimicrobial effects of dental materials are able to reduce the risk of secondary caries formation.

Difference in bonding/debonding chair time between a resin-modified, self-cured glass ionomer cement and a composite resin: a randomized clinical trial

The purpose of this study was to compare the bonding and debonding times of orthodontic brackets with a resin-modified, self-cured glass ionomer cement to that of a standard composite resin in a split-mouth study design. The chair time required for these procedures was assessed on 15 consecutive patients (nine females and six males). In this split-mouth study design, the oral cavity was divided into quadrants. In eight patients, the maxillary left and the mandibular right quadrants were bonded with glass ionomer cement and the remaining quadrants using the control composite resin. In the remaining seven patients, the quadrants were inverted. Thus, 150 brackets with 0.022′′ slots (Orthos, Ormco/“A” Company, Orange, CA) were bonded with the glass ionomer cement (GC Fuji Ortho, GC America Inc., Chicago, IL) and the remaining 150 with a standard composite resin (System 1+, Ormco/“A” Company, Orange, CA). The bonding time was recorded from the end of the initial polishing phase to the bonding of the last bracket for each quadrant. Patients were followed until the end of orthodontic therapy. The debonding time was recorded from the removal of the first bracket to the residual adhesive removal from the last tooth per each quadrant. The mean bonding time per quadrant (five teeth) required with GC Fuji Ortho (1 min, 58 s) was significantly shorter (p 0.05) between the upper and lower arches. In both arches, System 1+ required a significantly longer (p 0.05) between the upper and lower arches within each bonding material. In both arches, teeth bonded with System 1+ required a significantly longer (p<0.05) debonding time than those bonded with GC Fuji Ortho.