Browsing by Subject "Glass Ionomer Cements"
Now showing 1 - 10 of 14
Results Per Page
Sort Options
Item A Comparison of Three Debonding Techniques Employing Two Different Cements(2004) McCabe, Russell; Katona, Thomas R.; Baldwin, James J.; Hohlt, William F.; Moore, B. Keith; Shanks, James C.The theory and practice of bonding orthodontic brackets to enamel has become the accepted standard. However, regardless of the adhesive of choice, much controversy exists regarding bond strength values and testing protocols. Most bond strength testing has been done in either shear/shear-peel or tension. Some studies have used shear and tension and very few have used shear, tension and torsion. Some authors contend there is no difference in the stress required to produce bond failure by either tensile or shear test models. However, it has been shown that stress is not distributed uniformly during loading and each mode of strength testing produces unique stress patterns. Additionally, since in the oral cavity brackets are subject to shear, tensile and torsion forces, it seems logical that a complete picture of bond strength could not be formulated without all three test methods. Confounding the issue is the fact that adhesive research is being performed in non-standardized manners making it impossible to compare results among different researchers. Despite the vast amount of information presented in articles, this has resulted in a lack of consensus regarding clinical bond strength values. The purpose of this investigation was to evaluate the three debonding techniques (shear-peal, tension, torsion) using stainless steel brackets and two different bonding agents (traditional resin cement vs. resin reinforced glass ionomer). The hypotheses of this investigation were (1) the relative shear-peal, tensile and torsional bond strengths will show consistent results and (2) cement type will have a significant effect on the bond strengths. One hundred sixty-two bovine incisors were randomly assigned to 6 groups of 27 specimens per group. Teeth were bonded with either a resin composite adhesive or a resin reinforced glass ionomer cement following manufacturers' instructions. Bonding was performed under controlled temperature and humidity (71 °F± 2° and 56% RH± 5%). In addition, specimens were bonded utilizing a bonding jig that held the thickness of the adhesive constant at 0.006 inches. All groups were tested to failure using the MTS Bionix machine in shear, tension and torsion. The results showed that the resin composite had a significantly higher load at failure in shear and torque than the resin-modified glass ionomer. However, in tension, no significant difference was found between the two cements. Additionally, analysis of relative strength indicated a difference between shear strength and tension suggesting that testing mode influences bond strength values. It is the conclusion of this study that the load at failure for resin composite and resin-modified glass ionomer are not consistent and depend on the loading mode.Item Clinical Evaluation of Glass Ionomer Cement as an Adhesive for the Bonding of Orthodontic Brackets(1988) Miller, James R.; Garner, LaForrest D.; Moore, B. Keith; Shanks, James C., Jr.; Barton, Paul; Potter, Rosario H.Glass ionomer cement has been shown in previous studies to retard decalcification and caries formation. This cement would be valuable in orthodontics if it proved to have adequate adhesive properties. Therefore, this study was designed to determine if there is a significant difference in the failure rate of brackets attached to teeth using a glass ionomer cement, Ketac-fil, and the failure rate of brackets attached to teeth using a conventional orthodontic adhesive system, Rely-a-bond. Six patients in the Department of Orthodontics at Indiana University School of Dentistry participated in this study. Each patient had 16 to 20 teeth available for bracketing. Direct-bond orthodontic brackets were attached to one-half of each participant's available teeth using Ketac-fil. Rely-a-bond was used to bond brackets to the remaining half of the teeth. Fifty-three brackets were placed with Ketac-fil, and 53 with Rely-a-bond. This study lasted a minimum of ten weeks for each patient. The following observations were made: 1) The failure rates for brackets attached with Ketac-fil and those attached with Rely-a-bond. 2) The type of bracket failure for brackets bonded with Ketac-fil. 3) Pre-study and post-study decalcification patterns of teeth with brackets attached with Ketac-fil. The bracket failure rate was 3.77% for the Ketac-fil group and 5.66% for the Rely-a-bond group. There was no significant difference between the failure rates of these two groups at the alpha = 0.05 level when tested with the Fisher Exact Probability Test. Of the two brackets that failed in the Ketac-fil group, only one was available for examination and it demonstrated a definite adhesive type of bracket failure. With respect to decalcification patterns, no obvious change in pattern occurred for teeth in the Ketac-fil group. There was no statistical difference between the failure rates of brackets attached with Ketac-fil and those attached with Rely-a-bond. Previous studies have shown that glass ionomer cements release fluoride and that this may retard decalcification and caries formation. Decalcification and caries formation around the margins of orthodontic brackets have been identified as potential risks of orthodontic treatment. Thus, the use of a glass ionomer cement as a bonding agent in orthodontics might reduce these potential risks without compromising the attachment of the brackets to teeth. This study provides the basis for more extensive clinical trials of glass ionomer cements as bonding agents for direct-bond orthodontic brackets.Item Comparison of Tensile Bond Strengths of Glass Ionomer Cements Using Hydroxyapatite Coated and Uncoated Orthodontic Brackets(1993) Ng, Richard I. Cheng Hin; Hohlt, William F.; Moore, B. Keith; Oshida, Yoshiki; Garetto, Lawrence P.; Roberts, W. Eugene; Shanks, James C.The use of glass ionomer cements (GIC) in orthodontics as a bonding agent has been receiving considerable attention due to its favorable properties, ie., physico-chemical adhesion to enamel, fluoride leaching capabilities and less traumatic bonding procedure to tooth structure. GIC ability to bond to the hydroxyapatite (HA) in the tooth enamel was tested utilizing an HA coated bracket developed by American Orthodontics. This study compared in vitro tensile bond strengths of four dental adhesives: Ketac-cem™ (KC), Vitrebond™ (VB), Transbond™ (TB) or Unite™ (UN), when used to bond to HA coated brackets and non-HA coated brackets. Bovine incisors were divided into eight groups of 20 specimens each. Each group included either an HA coated or non-HA coated bracket and one of the four adhesives. The brackets are manufactured with a Tricalcium Phosphate (TPC) coating, which is converted to an HA coating by the addition of -OH during autoclaving. The coated and non-coated brackets were bonded to the bovine teeth, which were embedded in epoxy resin blocks to fabricate the testing specimen. All of the specimens were stored in distilled water at room temperature for two weeks. This was followed by thermocycling after which the specimens were returned to water storage for an additional two weeks. The specimens were tested in tension on an lnstron Testing Machine until bond failure occurred. Mode of bond failure was determined visually by light microscope. The mean tensile bond strengths for KC and VB were each significantly less (p< 0.05) than the other three materials, while UN and TB were not significantly different. KC was the weakest at 0.68± 0.31 MPa, while UN was the strongest, 4.38±0.84 MPa. When comparing the GIG alone, there was a significant difference (p<0.0001) between the VB and the KC. The resins were not significantly different from each other. Differences between coated and non-coated were significant at p<0.05 with the noncoated brackets having the higher strength. Adhesive failure at the bracket interface for the two bracket types showed no difference for KC. TB and UN showed this type of failure significantly more with the coated brackets (p<0.05), and VB showed the opposite and more failure with non-coated brackets (p<0.01). The tensile bond strength of GIG continues to be significantly less than those of existing resins. The bond failure also revealed a high degree of within group variability. Trends relating failure mode to tensile bond strength could not be established. Greater bond strengths with the coated brackets and the GIG were not shown; however in the case of VB, the tendency for the coated brackets to fail less frequently at the bracket adhesive interface shows some promise. Further studies of these coated brackets are still warranted.Item Enamel conditioning effect on penetration and microleakage of glass ionemer-based sealants(2009) Ahmed, Senan Raad; Cabezas, Carlos Gonzales; Chu, Tien-Min Gabriel; Fontana, Margherita Ruth, 1966-; Matis, Bruce; Cochran, MichaelWhile most sealants available are resin-based, glass ionomer-based cements can be used as sealants, with the advantage of being more tolerant to moisture during placement and of releasing fluoride. The objective of this study was to evaluate the influence of different fissure conditioning techniques on penetration and microleakage of glass ionomer (GI) and resin-modified glass ionomer cements (RMGI) used as sealants. Clinically sound extracted human molars were distributed into nine experimental groups (n = 15 each). Group 1 (control) was sealed with resin-based sealant (Delton) following clinically accepted techniques. Groups 2 through 6 were sealed with RMGI (Vitremer) after having the fissure conditioned with either polyacrylic acid (RMGI-control), 35-percent H3PO4, low viscosity 35-percent H3PO4 with a surfactant, self-etch conditioner, or 35-percent H3PO4 followed by self-etch conditioner. Groups 7 through 9 were sealed with GI sealant (Fuji Triage) after having the fissures conditioned with either polyacrylic acid (GI-control), 35- percent H3PO4 or low viscosity 35-percent H3PO4 with a surfactant. After aging through thermocycling (2500 cycles), specimens were incubated in methylene blue for four hours and sectioned at multiple locations. Digital images were obtained using a digital stereomicroscope, and microleakage was determined by scoring the dye penetration along the enamel-sealant interface. The penetration of the material was determined by calculating the percentage of the total length of the fissure penetrated by the material. Results: The use of self etch-conditioner significantly increased RMGI penetration, while surface conditioning with 35-percent phosphoric acid with surfactant significantly decreased microleakage of GI. The resin-based sealant placed after 35-percent phosphoric acid surface conditioning showed the best penetration and the least level of microleakage. In conclusion, results from this study suggest that the placement of glass ionomer-based sealants can be enhanced by modifying current conditioning methods.Item Evaluation of Tensile Bond Strength of Glass Ionomer Cements for Orthodontic Bonding(1992) Sprayberry, W. Ray; Katona, Thomas R.; Arbuckle, Gordon R.; Moore, B. Keith; Roberts, W. Eugene; Shanks, James C.Glass ionomer cements offer advantages over conventional composite resins when used for orthodontic bonding. These include chemical bonding to enamel, fluoride release, and ease of removal from enamel upon debonding. This study evaluated the tensile bond strengths of three Type I (luting) and three Type II (restorative) glass ionomer cements when used to bond a standard stainless steel orthodontic bracket to teeth. Bovine incisors were divided into six groups of 20 each. Each group had brackets bonded with one of the following glass ionomer cements: SHOFU ® Glasionomer Type I, Fuji I™, Ketac ®-cem, SHOFU ® Glasionomer Type II, Fuji II ™, and Ketac®-fil. A new regimen of specimen preparation was used in an attempt to align the brackets so that true tensile forces could be generated at testing. After the specimens were prepared, they were stored in room temperature water for two weeks, thermocycled, returned to water storage for two additional weeks, and then tested in tension on an lnstron Testing Machine until bond failure occurred. The type bond failure was determined with light microscopic analysis of the debonded bracket bases. The finite element method was used to further evaluate the bracket/adhesive/enamel complex with varying angulation of force application at debonding. The mean tensile bond strength value of 0.82 ± 0.36 MPa for SHOFU® Glasionomer Type I was significantly less (p<0.05) than the values of 1.13 ± 0.33 MPa for Ketac®-cem and 1.26 ± 0.40 MPa for Fuji I™. For the Type II glass ionomer cements, the mean tensile bond strengths of 2.00 ± 0.28 MPa for Ketac®-fil and 1.97 ± 0.29 MPa for Fuji II™ were significantly greater (p<0.05) than the 0.95 ± 0.35 MPa for SHOFU® Glasionomer Type II. The Ketac® and Fuji™ Type II cements developed bond strengths which were significantly greater (p<0.0001) than the Type I cements. Light microscopic analysis of bond failure revealed a high degree of within group variability. As a result, trends relating failure mode to tensile bond strength could not be established. The finite element method study showed that even a slight alteration in angulation of the force applied to the bracket greatly affected the maximum principal stress developed in the adhesive layer. An increase in maximum principal stress of ≈1,000 MPa was seen when a true tensile debonding force (0° offset) was adjusted to 12° of offset. The results of this study indicate that Type II glass ionomers have potential for clinical orthodontic use and that special attention should be given to the angulation of force applied to brackets in laboratory bonding studies.Item Evaluation of the Tensile Bond Strength of Orthodontic Bracket Bases Using Glass Ionomer Cement as an Adhesive(1992) Burns, Richard D., Jr.; Roberts, W. Eugene, Jr.; Garetto, Lawrence P.; Moore, B. Keith; Miller, James R.; Shanks, James C., Jr.; Hennon, David K.The search for an orthodontic bonding adhesive that has chemical adhesion to enamel and releases fluoride into the oral environment has led to experimentation with glass ionomer cements. This study compared the tensile bond strength of eight different orthodontic bracket base designs in vitro and assessed the amount of adhesive remaining on the bracket pad after debonding. Each bracket base design included in this study had unique characteristics warranting their inclusion. The groups contained brackets with 60, 80, and 100 gauge mesh pads; 100 gauge mesh sandblasted pads; perforated metal bases; Micro-Lock™ photo-etched bases; Dyna-Lock™ integral bracket/bases; and ceramic silane-coated bracket pads. Groups contained 20 to 22 specimens that were bonded to bovine incisor teeth embedded in a self-curing acrylic block that could be held in the testing machine. Pre-encapsulated glass ionomer cement (Ketac-Fil™) was the experimental adhesive. The adhesive was mixed according to the manufacturer's instructions in a dental amalgamator. The specimens were thermocycled between water oaths of 15°C and 55°C. The specimens spent 30 seconds in each bath for a total of 2,500 cycles and were stored in a humidor until debonding. After 14 days, the specimens were subjected to a tensile force using an Instron mechanical testing machine until failure occurred. The Micro-Loc™ photo-etched base had significantly higher mean tensile bond strength (p<0.05) than all other brackets tested. The ceramic brackets were unable to be tested due to the extremely weak bond strength which did not allow preparation of the samples for debonding. Following debonding, the percentage of adhesive remaining attached to the bracket base was determined using a grid in the ocular of a light microscope. In general, the site of bond failure involved the base/adhesive interface. The Dyna-Lock™ integral bracket/base and 80 gauge mesh base had a greater mean percent of adhesive remaining attached to the base. (Dyna-Lock™ 45 percent and 80 gauge mesh 43 percent vs. all other < 20 percent.) The results indicate that the bracket base design can influence the bond strength when GIC is used as an orthodontic adhesive and suggests that development of GIC with increased fracture toughness might increase bond strength.Item Evaluation of water sorption and solubility behavior of nine different polymeric luting materials(2009) Alsheikh, Rasha N.; Platt, Jeffrey A.; Lund, Melvin R., 1922-; Cochran, Michael A. (Michael Alan), 1944-; Moore, B. Keith; Matis, Bruce A.The cementation procedure is the key to long-term success of fixed restorations. The prognosis of prosthetic restoration is largely impacted by the maintenance of the luting cement and the adhesive bond. When exposed to water or saliva, most restorative materials undergo hydrolytic degradation. The purpose of this study is to evaluate the water solubility and water sorption characteristics of newly introduced acidic polymeric luting agents over a 180-day water-storage period. Nine different luting agents were tested. Fifty-two disc specimens of each material were fabricated using a mold with an internal dimension of 15[plus-minus]0.1 mm in diameter and 1.0 [plus-minus]0.1 mm deep. A constant weight, W0 [subscript zero], was reached after desiccating the specimens. Then, 13 specimens were assigned randomly to one of the four testing periods in the water for seven, 30, 90 and 180 days. After each period, the specimens were removed from the water and weighed to get W1 [subscript one]. A second period of desiccating the samples provided a constant weight W2 [subscript two]. The water sorption and solubility were determined by the following equations: WSP [subscript SP](%) = (W1 [subscript one] W2 [subscript two] ) X 100/ W0 [subscript zero] ,WSL [subscript SL](%) = (W0 [subscript zero] W2 [subscript two) X 100/ W0 [subscript zero]. The resin-modified glass-ionomers showed the highest water sorption/solubility results. The resin luting agents had the lowest sorption/solubility results. The self-adhesives showed a wide range of solubility/sorption; in general, they showed lower results compared with the resin-modified glass-ionomers. All the materials reached some sort of equilibrium after 90-days. Based on the results of our study, we conclude that self-adhesive luting materials were not all alike. Rely X Unicem was the most comparable to the resin luting materials. The resin luting materials had the lowest solubility and sorption. Resin-modified glass-ionomers showed the highest sorption/solubility results.Item Fragment reattachment with light-cured glass-ionomer(1996) Minutillo, Anthony L., 1965-; Dean, Jeffrey A.; Bowman, Dennis; Moore, B. Keith; Sanders, Brian S.; Avery, David R.This investigation examined the relationships among light cured glass ionomer liner, light cured glass ionomer base, and composite resin material in the reattachment of fractured anterior tooth fragments. Seventy-five bovine incisor teeth were fractured and luted back together with three different materials (Universal Bonding Agent/TPH Composite Resin; VariGlass VLC Liner; VariGlass VLC Base, LD Caulk Div Dentsply Int Inc, Milford, DE) of equal number. The reattached fragments were subjected to thermocycling with a 40° C differential and then were loaded until the force required to detach the fragment was reached. The mean dislodgment strengths were 36.8 (± 25.6)kg for the composite resin, 36.4 (± 26.7)kg for the glass ionomer base, and 31.4 (± 29.S)kg for the glass ionomer liner. Analysis of variance demonstrated no significant difference between the three groups at p≤0.05. Also examined was the type of fracture after reattachment. Of the sixty-five teeth that were studied microscopically, 84.6 percent of the fractures were cohesive in nature, thus a breakdown occurred within the material itself.Item Longevity of Crown Margin Repairs Using Glass Ionomer: A Retrospective Study(2020) Watson, Justin I.; Cook, N. Blaine; Thyvalikakath, Thankam; Diefenderfer, Kim E.; Capin, OrianaObjectives: Repair of crown margins may extend the functional life of existing crowns. However, the longevity of such treatment is unknown. This study determined the survival time of crown margin repairs (CMR) with glass-ionomer (GI) and resin-modified glass-ionomer cements. Methods: We queried axiUm (Exan Group, Coquitlam, BC, Canada) database for permanent teeth that underwent CMR in the Graduate Operative Dentistry Clinic, Indiana University School of Dentistry (IUSD), Indianapolis, Ind., USA, from January 1, 2006 through January 1, 2018. Since there is no CDT code for the CMR procedure, CDT codes for resin-composite and GI restorations (D23XX) were queried; these patients also had treatment notes that indicated CMR. The final data set included patient ID, birth date, gender, dates of treatments, CDT codes, tooth type, tooth surface and existing findings. Two examiners developed guidelines for record review and manually reviewed the clinical notes of patient records to confirm CMR. Only records that were confirmed with the presence of CMR were retained in the final dataset for survival analysis. Survival time was calculated by Kaplan-Meier statistics and a Cox Proportional Hazards model was performed to assess the influence of selected variables (p < 0.05). Results: 214 teeth (115 patients) with CMR were evaluated. Patient average age was 69.4 11.7 years old. Posterior teeth accounted for 78.5 percent (n = 168) of teeth treated. CMRs using GI had a projected 5-year survival rate of 62.9 percent (K-M Analysis) and an 8.9 percent annual failure rate. Cox Proportional Hazards Regression analysis revealed that none of the factors examined (age, gender, tooth type) affected time to failure. Conclusion: CMRs may extend the longevity of crowns with defective margins. Larger EHR studies or case control studies are needed to investigate other variables, such as the caries risk status or the severity of defects that may affect the survival rate of CMRs.Item Microtensile bond strength of new paste/paste resin-modified glass ionomer cement systems : the effect of dentin pretreatment(2011) Al-Fawaz, Yasser Fawaz, 1983-; Cook, Norman Blaine, 1954-; Hara, Anderson T.; Matis, Bruce A.; Cochran, Michael A. (Michael Alan), 1944-; Bottino, Marco C.MICROTENSILE BOND STRENGTH OF NEW PASTE/PASTE RESIN-MODIFIED GLASS IONOMER CEMENT SYSTEMS: THE EFFECT OF DENTIN PRETREATMENT by Yasser Fawaz Al-fawaz Indiana University School of Dentistry Indianapolis, Indiana Background: In order to improve the clinical performance of RMGIC 3M ESPE and GC America introduced paste/paste resin-modified glass ionomer cements, Ketac™ Nano and Fuji Filling™ LC, respectively. Both companies developed non-rinse substrate conditioners (i.e., Ketac Nano Primer-3M ESPE and GC Self-Conditioner-GC America) that should be used with these new materials instead of the conventional polyacrylic acid. It has been also advised by both manufacturer’s to use this novel substrate conditioner with the previously marketed RMGICs. Objective: to investigate whether the use of novel non-rinse conditioners (i.e., Ketac Nano Primer 3M ESPE and GC Self Conditioner GC America) as substrate pre-treatment and the new paste/paste resin-modified glass-ionomer cement, RMGIC (Ketac™ Nano 3M ESPE and Fuji Filling™ LC GC America) would affect the microtensile dentin bond strength (µTBS) of the material when compared to the traditional RMGIC with polyacrylic acid as a surface substrate pre-treatment. Materials and Methods: 96 extracted non-restored human molar were sectioned to expose occlusal dentin. Dentin surface was finished with SiC paper to standardize the smear layer. Bonding protocols of the different materials to dentin were performed following the use of two dentin conditioners. Eight groups (n=12) were tested: G1: Ketac Nano Primer + Ketac Nano, G2: Ketac Conditioner + Ketac Nano, G3: Ketac Nano Primer + Photac Fil, G4: Ketac Conditioner + Photac Fil, G5: GC Self Conditioner + Fuji Filling LC, G6: GC Cavity Conditioner + Fuji Filling LC, G7: GC Self Conditioner + Fuji II LC and G8: GC Cavity Conditioner + Fuji II LC. The specimens were stored in 37°C for 24h in 100% humidity before cutting non-trimmed beams for the µTBS with cross-sectional areas of approximately 0.8 × 0.8 mm2. Nine beams were used from each specimen. Test was done using universal testing machine at a cross-head speed of 1mm/min. Debonded specimens were examined under a stereomicroscope at 45× magnification to evaluate the failure mode. Eight randomly chosen representative debonded beams were imaged under a scanning electron microscope (SEM). Results: µTBS in MPa (mean ± SE) were: G1: 9.5±1.0, G2: 11.0±1.0, G3:20.0±1.0, G4:16.8±0.9, G5: 15.1±1.0, G6: pre-test failure, G7: 20.0±1.0, G8:14.1±0.9. Weibull-distribution survival analysis was used to compare the differences in microtensile peak stress among the groups. Group5 has cohesive predominant faultier mod while the other groups have adhesive predominant failure. Conclusion: Within the limitations of this study, the use of the novel non-rinse conditioners did not improve the microtensile bond strength of new paste/paste RMGIC to dentin. In fact, the use of the novel non-rinse conditioners enhanced the bond strength of the traditional RMGIC to dentin.