Browsing by Subject "Dental Cements"

Now showing 1 - 10 of 15
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    Clinical Evaluation of a Universal Adhesive in Non-Carious Cervical Lesions
    (2016) Rouse, Matthew A.; Platt, Jeffrey A.; Jackson, Richard D.; Carlson, Timothy J.; Matis, Bruce A.; Cook, Norman Blaine
    The “total-etch” or “etch-and-rinse” systems have been the gold standard of dental bonding for decades. However, these systems are very technique-sensitive and time-consuming compared to newer “self-etch” or “self-adhesive” systems and have been implicated in cases of postoperative sensitivity. The purpose of this study was to compare the effects of two surface treatment protocols (self-etch vs. selective-etch) on the clinical performance of a universal adhesive and resin composite in Class V non-carious cervical lesions (NCCLs). Thirty-three volunteer subjects (17 male; 16 female; age range = 20 to 75 years) having at least two NCCLs were selected from patients of record at Indiana University School of Dentistry. Each subject received one resin composite restoration (Tetric EvoCeram, Ivoclar Vivadent) utilizing a self-etch (SfE) universal adhesive (Adhese Universal, Ivoclar Vivadent) with no separate enamel etching and another restoration utilizing adhesive and selective enamel etching (SelE) with 37% phosphoric acid (H3PO4). Both the adhesive and composite were placed following the manufacturer’s instructions. The two techniques were compared for differences in sensitivity, retention, marginal discoloration, marginal adaptation, and clinical acceptability at baseline and 6 months using the Cochran-Mantel-Haenszel tests for stratified, ordered categorical outcomes. Seventy-four restorations (37 SfE, 37 SelE) in 30 volunteers were evaluated at 12 months. No significant differences were found between the SfE and SelE groups for any variable at the 12-month recall (p>0.21). Retention was 100% at 12 months for both groups. Marginal adaptation was significantly worse at 12 months than at baseline for SelE (p=0.0163), but there was no difference for SfE (p=0.08). Sensitivity improved significantly from baseline to 12 months for both SelE (p=0.0113) and SfE (p=0.0128). The results obtained from this study are comparable to results observed in similar studies. Like similar studies involving self-etch adhesives in non-carious cervical lesions, our study showed no restorations lost to caries and excellent retention. The deterioration of selective-etch dentin margins was a result that differed from similar studies. A likely explanation for this finding would be the difficulty of controlling precise placement of phosphoric acid gel, causing undesired etching of dentin; this could result in suboptimal bonding to dentin. This report on 12-month data for a two-year study indicates significantly reduced sensitivity for both the SelE and SfE groups, and deterioration of SelE marginal adaptation. No decreases in retention, marginal discoloration, or clinical acceptability were observed in either group.
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    Comparative Tensile Strengths of Brackets Bonded to Porcelain with Orthodontic Adhesives and Porcelain Repair Systems
    (1986) Eustaquio, Robert I.; Garner, LaForrest D.; Barton, Paul; Hennon, David K.; Moore, B. Keith; Muñoz, Carlos; Shanks, James C.
    This study evaluated the feasibility of bonding brackets to porcelain for orthodontic purposes by measuring and comparing tensile strengths of five silane-based adhesive systems. Each adhesive system bonded mesh pad brackets to 10 glazed and 10 deglazed metal-ceramic crowns and the specimens were then thermocycled between 16 degrees and 56 degrees for 2500 cycles. Clinically relevant bond strengths, comparable to those of adhesives bonding brackets to enamel, were recorded for four of the systems compared. System l+ and Porcelain Primer had the highest mean values followed by Lee's Enamelite 500, then Vivadent's Silanit, Contact-Resin and Isopast, then 3M's Concise and Scotchprime. Most, if not all, failure sites for the four were at the bracket-resin interface. Two-way factorial analysis of variance demonstrated significant differences at P<.001 among the four adhesives but no contribution of surface effect, whether glazed or deglazed, was suggested statistically. Neuman-Keul sequential range tests showed significant differences between System l+ and the three other systems but no significant differences among the three were detected. Den-Mat's Ultrabond recorded extremely low tensile strength values and was of dubious clinical value. A t-test suggested that deglazing porcelain contributed no significant difference in strength compared with intact, glazed porcelain. All failure sites were at the porcelain-resin interface for this product. Since resin may remain bonded to porcelain following debonding, George Taub's diamond polishing paste and Shofu porcelain polishing wheels were compared as to their ability in restoring the porcelain to its original state. Because of the great adhesive bond of the resin to porcelain, craters, pits or tears may be created when resin is cleaned from porcelain with conventional scalers and pliers. The diamond paste gave a better restorative finish than the stones but the end result depended on the extent of original damage following cleaning. Orthodontists should take this point into account when considering bonding to porcelain crowns or veneers for esthetics sake where final risks may outweigh initial benefits. In a limited survey of 100 orthodontists responding to a questionnaire, 89% indicated that they have bonded or contemplated bonding to composite restored teeth, and 83% indicated that they have bonded or contemplated bonding to porcelain.
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    Effect of Chlorhexidine-Encapsulated Nanotube-Modified Adhesive System on the Bond Strength to Human Dentin
    (2019) Kalagi, Sara Arfan; Cook, N. Blaine; Diefenderfer, Kim; Bottino, Marco; Feitosa, Sabrina
    Introduction: The resin-dentin interface undergoes degradation by endogenous matrix metalloproteinases (MMPs) after adhesive procedures. Application of several MMP inhibitors such as chlorhexidine (CHX) to the demineralized collagen dentin matrix after acid-etching has been suggested to be a successful approach to prevent degradation of the hybrid layer. Further, nanotubes (HNT) have been used as a reservoir for encapsulation and controlled delivery for several therapeutic drugs with sustained release. Therefore, HNT can be encapsulated with CHX and incorporated into dentin adhesives for the possibility of enhancing the longevity and durability of the hybrid layer. Objective: To evaluate the effect of a CHX-encapsulated nanotube-modified primer/PR and adhesive/ADH on the microtensile resin bond strength (µTBS) to dentin. Materials and Methods: A commercial adhesive and its respective primer were modified by adding CHX-encapsulated nanotubes at two distinct concentrations (10 and 20 wt.%). The experimental adhesives were evaluated by degree of conversion (DC) and viscosity. Meanwhile, only viscosity was determined for the experimental primers. The prepared HNT-encapsulated with CHX (10 and 20 wt.%) powders were incorporated into the primer and/or adhesive according to the groups: ADH (control); HNT (control); 0.2% CHX; PR+CHX10%; PR+CHX20%; ADH+CHX10%; ADH+CHX20%. Human molars were selected and autoclaved; mid-coronal dentin surfaces were exposed for bonding purposes. Dentin surfaces were etched, followed by primer and adhesive application, and restored with a resin composite. After 24 hours, the teeth were sliced into beams for µTBS testing; beams collected for each tooth were equally assigned into two testing condition groups: 24 hours and 6 months. Microtensile bond strength was tested using a universal testing machine, and the types of failure were classified as adhesive, mixed, and cohesive failure. Data from DC and viscosity tests were analyzed using one-way ANOVA. Bond strength data were analyzed by pair-wise comparisons using the Sidak method to control the overall significance level at 5% for each aging time separately. Weibull-distribution survival analysis was used to compare the differences in the microtensile bond strength results among the groups after 24 hours and 6 months. Results and Conclusion: DC analysis revealed no significant differences among adhesive groups. However, ADH group had a significantly lower viscosity than modified adhesive groups, and a significantly higher viscosity than modified primer groups. Test results of stress value (MPa) by each group for each aging time revealed no significant differences among groups after 24 hours. However, after 6-month storage, modified primer groups (PR+CHX10%, PR+CHX20%) and 0.2%CHX group showed a significant difference in µTBS compared to control groups (ADH, HNT) and modified adhesive groups (ADH+CHX10%, ADH+CHX20%) in the same aging time testing (p < 0.05). When comparing the µTBS after 24 hours and 6 months, there were no significant differences among the groups except for the ADH+CHX20% group, for which MPa values were higher after 24 hours than 6 months (p = 0.0487). In conclusion, this study has demonstrated the great potential of modified dental primers with CHX-encapsulated nanotubes in preservation of the resin-dentin bond strength over a 6-month time period. Additionally, modification of dental primers and adhesives was a successful approach that didn’t compromise the characteristics or the mechanical properties of the materials and has a promising long-term effect on resin-dentin bond strength.
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    Effect of low concentrations of antibiotic intracanal medicaments on crown discoloration and push-out bond strength
    (2018-07-12) Yaghmoor, Rayan Bahjat M.; Platt, Jeffrey A; Yassen, Ghaeth; Spolnik, Kenneth J.; Chu, Tien Min Gabriel
    Introduction: Some intracanal medicaments used in regenerative endodontics may compromise the bond strength of root cements and lead to tooth discoloration. Objectives: To evaluate the effects of 1) low concentrations of TAP and DAP (1 mg/mL) on push-out bond strength of various root cements, and 2) low concentrations of TAP and DAP (1 mg/mL and 10 mg/mL) on crown discoloration. Materials and Methods: Single rooted human teeth (n = 144) were horizontally decoronated and instrumented according to standardized protocol. The samples were randomized into six experimental groups (Ca(OH)2, 1000 mg/mL TAP and DAP, 1 mg/mL TAP and DAP, and no medicament control group. After four weeks, the medicaments were removed and each group was divided into three subgroups to receive MTA cement, Biodentine cement, or Endosequence Bioceramic putty cement for two weeks. Then, two root cylinders were obtained from each root and push-out bond strength testing was performed. For the crown discoloration experiment, 160 crowns were obtained from intact human molars and randomized into experimental groups as described earlier with the addition of two groups (10 mg/mL TAP and DAP). The pulp chambers in half of the samples from each group were coated with an adhesive bonding agent before receiving the assigned intracanal medicament. Color changes (ΔE) were detected by spectrophotometer at 1 day, 1 week, and 4 weeks after application, as well as after thermocycling. Results: In the push-out bond strength experiment, 1 mg/mL DAP generally demonstrated significantly higher bond strength of root cements compared with the other treatment groups. For the crown discoloration experiment, when an adhesive bonding agent was used prior to (10 mg/mL or 1000 mg/mL) TAP, the crowns had significantly less discoloration than those without adhesive. DAP 10 mg/mL had the least significant color change at all time points regardless of whether adhesive was used. Conclusion: 1) 1 mg/mL DAP and Ca(OH)2 did not have significant negative effect on the bond strength of calcium-silicate-based cement to radicular dentin. 2) 1 mg/mL and 10 mg/mL of DAP and Ca(OH)2 had significantly less effect on the color change of the human tooth crown than all intracanal medicaments used in this study.
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    Effectiveness of universal adhesive bonding agents on the shear bond strength to lithium disilicate ceramics
    (2015) AlRabiah, Mohammed A.; Platt, Jeffery A.; Levon, John A.; Brown, David T.; Chu, Tien-Min Gabriel; Bottino, Marco C.
    Background: All-ceramic restorations have excellent esthetic outcomes compared with other restorative materials. Lithium disilicate is classified as one of many silica-based all-ceramic materials. Currently, companies have provided single-step adhesives, known as universal adhesives, compatible with different restorative materials including lithium disilicate. Many studies have reported greater bond strengths when using a silane to treat the lithium disilicate before applying the bonding agent. Moreover, few studies were published comparing the bond strength when using the universal adhesive alone. Purpose: The objective of this study was to evaluate and compare shear bond strength of three universal adhesives to lithium disilicate ceramic restorative material. Materials and Methods: Three universal adhesive bonding agents were selected from commercially available adhesives. 408 IPS e.max CAD ceramic discs were processed, fired, and etched for 20s. The specimens were divided into six groups. The first three groups used the universal adhesive directly. The remaining three groups were treated with silane. Then, a composite resin cylinder was placed on top of the adhesive using a bonding jig. Each group was subdivided into four equal subgroups (n = 17), subjected to different aging simulation procedures: 24 h, one month with 5000 thermocycles, two months with 5000 cycles, and three months with 5000 cycles. Then, specimens were debonded using shear force by a universal testing machine (MTS). Results: Shear bond strength was greater with silane than without silane (p < 0.0001), regardless of the levels of adhesive or time. Shear bond strength was significantly greater at 24h and 1m than at 2m (p < 0.0001) or 3m (p < 0.0001) regardless of the adhesive or the presence of silane. Debonded specimens were examined under a stereomicroscope at X45 magnification to evaluate the fracture pattern. SEM was used to prove the results were considered as mixed failure. Conclusion: The optimal bonds to lithium disilicate are achieved by application of silane prior to application of a universal adhesive. Although the constituent silane in the universal adhesive was not effective in optimizing the resin to ceramic bond, silane should always be applied to lithium disilicate prior to bonding.
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    Evaluation of Tensile Bond Strength of a Fluoride-Releasing Resin Adhesive with Ceramic Brackets
    (1991) Lehman, David Alan; Roberts, W. Eugene; Moore, B. Keith; Shanks, James C.; Arbuckle, Gordon R.; Miller, James R.
    The increased attention to the esthetics of orthodontic appliances has led to the popularity of ceramic brackets in the last decade. Although the bonding of ceramic brackets has become predictably successful, the extreme brittleness of ceramics coupled with higher bond strengths has caused significant clinical problems in debonding and risk of enamel damage. This study evaluated an experimental bonding resin with different levels of fluoride concentration, linking the therapeutic property of long-term fluoride release to the benefit of decreased bond strength to ceramic brackets. Four groups of 40 Transcend™ ceramic brackets each were bonded to bovine teeth, using 0, 3, 6, and 12 percent fluoride concentrations. At two weeks, one-half of each group was tested for tensile bond strength in an lnstron machine. The remaining half were tested at six months. In the groups broken at two weeks, the bond strength peaked around 6 percent fluoride, but the three top groups were not significantly different. In the groups tested at six months, peak strength was observed at 3 percent fluoride and was significantly greater than the others. The overall mean at six months than at two weeks. The study found bond strength values in the range of 25-50 kg/cm2. Although minimum values have not been established, the low values reported in this study are likely to be within acceptable clinical limits. Following debonding, the mode of bond failure was determined by viewing enamel specimens and bracket bases under a light microscope. In all but one group, 95 percent of the bond failure occurred at the bracket base/adhesive interface. No bracket failure occurred and no enamel damage could be observed under the light microscope. In a parallel study of physical properties, Knoop hardness was measured at one hour, 24 hours, and six months, and compressive strength was tested at one week and six months. While physical properties generally decreased over the period of study, bond strength was significantly greater in the six-month group. The results of this study regarding the correlation of these properties to bond strength is inconclusive. In addition, results of fluoride-release data by SISCO Inc. indicate that the 12 percent group was shown to release greater than 10 μg/g/day at six months. This was comparable to amounts known to have the clinical benefit of reducing demineralization, and equaled or exceeded other commercially available fluoride-releasing adhesives. The results of this study indicate that a fluoride-releasing resin can release clinically significant amounts of fluoride ions, and still have adequate bond strength.
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    Evaluation of Tensile Bond Strength, Fluoride Release, Hardness, and Solubility of a Fluoride Containing Adhesive Resin
    (1994) Brandt, Marybeth; Moore, B. Keith; Zeldin, Martel; Katona, Thomas R.; Garetto, Lawrence P.; Roberts, W. Eugene
    Direct bonding of orthodontic brackets often results in decalcification of tooth structure surrounding bracket sites. Glass ionomer cements, while typically leaching fluoride over time, often exhibit a significantly lower bond strength. Fluoride-containing resins generally release high concentrations of fluoride for a short time, then cease to release any significant amount. The purpose of this study was to evaluate the tensile bond strength, fluoride release, hardness, solubility, and sorption of a newly formulated fluoride containing resin. The experimental resins were prepared with 5% and 7.5% fluoride (F-) monomer, and were compared to a fluoride-free control adhesive (Rely-a-Bond Phase II™, Reliance Orthodontics Inc ., Itasca, Ill .). To evaluate tensile bond strength, orthodontic brackets were bonded to bovine teeth and debonded using an lnstron machine. Fluoride release was tested using resin disks stored in deionized water. The fluoride content of the water was determined with an ion-specific electrode. Hardness, solubility, and sorption were tested using disks made of each material. Comparison of experimental and control resins by ANOVA followed by General Linear Models multiple comparisons revealed the control to show a statistically significant difference (p<.0001) for tensile bond strength. Experimental Control 5%F- 7.5%F- Peak Stress (MPa) 4.48±0.65 3.83±0.76 5.31±0.97. Fluoride continued to be released from the experimental resins (5% and 7.5% F-) at 18 days. The control was significantly harder than either of the experimental resins at 1 hour, 24 hours, 1 week, and 1 month (p<.0001). The 5% F- resin exhibited slight solubility (0.10 percent), while the 7.5%F- resin and the control exhibited very little solubility (0.01 percent). Phase II™ exhibited significantly lower sorption at 21 days (0.60 percent, p<.001) than either the 5%F- resin (1.69 percent) or the 7.5%F- resin (1.63 percent). These results indicate that while the experimental resin had lower bond strength, lower hardness, and higher sorption than the control, measurable fluoride was released from the experimental resins for up to 18 days. Further testing is indicated to determine the clinical acceptability of this adhesive.
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    An Evaluation of the Bond Strength and Failure Site of Composite Resin and Glass Ionomer in Identical Orthodontic Direct Bonding Systems
    (1989) Fryar, Brian C.; Garner, LaForrest D.; Moore, B. Keith; Newton, Carl W.; Shanks, James C.; Koerber, Leonard G.
    Glass ionomers offer several advantages for orthodontic cementation of brackets including no etching of enamel, fluoride release, and ease of debonding. This study compared in vitro bond strengths of glass ionomers with a composite resin. Two luting glass ionomers, (Ketaccem and Fuji I), two restorative ionomers, (Ketac-fil and Fuji II), and an orthobonding resin, (System 1 +), were used. Extracted human maxillary premolars were selected for a sample of 22 per cement. The teeth were pumiced prior to bonding. Ormco minimesh bicuspid brackets were bonded following manufacturer's directions. Only the teeth bonded with resin cement were etched. After bonding the teeth were stored in water at 37 C for 7 days and thermocycled 2500 times through a 40° c differential. Tensile bond strengths were measured at a crosshead speed of 0.5mm/min. Debonded specimens were examined to record failure modes. System 1+ had a bond strength of 103 +/- 21 kg/cm2 with 80% cohesive failure in the cement. Ketac-fil, Ketaccem and Fuji II were not significantly different and had strengths of 32.6 +/- 6.4, 31.9 +/- 7.1 and 33.7 +/- 8.5 respectively. Failure was 93% cohesive in the cements. Fuji I had a strength of 26. 6 +/- 4. 7 with 89% cohesive failure and was significantly weaker than the others. Although the strengths of the glass ionomers studied were substantially lower than the resin, they failed consistently in cohesive fracture through the cement with relatively small deviations. Since the minimum bond strength required for clinical success is not known, only a controlled clinical study can determine the ultimate effectiveness of glass ionomers as orthodontic bonding adhesives.
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    An Evaluation of the Frozen Slab Mixing Technique on the Physical Properties of Certain Dental Cements
    (1974) Coghlan, Charles Y.
    A method was devised to evaluate the effect of the "frozen slab" mixing technique on the physical properties of a zinc phosphate, zinc silicophosphate, hydrophosphate and polycarboxylate cement. Those properties studied were the setting time, compressive strength, tensile strength and solubility. Standardized mixing procedures were employed using predetermined powder/liquid ratios. Setting and working times were increased for all cements when mixed on glass slabs chilled to -15 c. All cements kept on the cold slab were still unset after 32 minutes. Compressive and tensile strengths were adversely affected by the "frozen slab" technique. All cements gave parallel reductions of the two strengths on the order of 20 percent except the polycarboxylate which exhibited only a 5 percent reduction in tensile strength. The polycarboxylate exhibited the highest tensile strength while its compressive strength was one half the others tested. Solubility samples were prepared and placed in 0.001M acetic acid at pH4. Solutions were changed daily and solubility was determined by the gravimetric method. The solubility of all cement was adversely affected. The zinc silicophosphate exhibited the highest and the polycarboxylate the lowest solubility of the cements tested. It was recommended that cements be mixed above the dew point and multiple mixes be used to ensure optimum physical properties.
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    A Modified Adhesive System for Use in Treatment of Dentin Hypersensitivity
    (2020-08) AlShehri, Aram Mushabbab; Sochacki, Sabrina Feitosa; Hara, Anderson; Platt, Jeffrey A.; Windsor, L. Jack