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To compare the in vitro strength of a reinforced glass ionomer and a light-cured glass ionomer used as an alternative to amalgam in core construction to restore endodontically treated mandibular molar teeth.The root canals of 120 extracted human mandibular molar teeth were prepared chemomechanically and obturated with laterally condensed cold gutta-percha. The crown of each tooth was sectioned leaving only one cusp standing. Gutta-percha was removed from the pulp chamber in all teeth. The volume of the pulp chamber was measured and the teeth ranked in ascending order of chamber volume. The specimens were divided into six groups of 20, allocating teeth with similar chamber volumes into each group. In three of the groups, gutta-percha was removed from the coronal 3-4 mm of each root canal. The teeth were restored with one of three materials, a cermet cement (Ketac-Silver), a resin-reinforced glass ionomer (Vitremer), or amalgam (Contour). Core preparation was carried out after 48 hours, reducing each core height to 6 mm. The specimens were thermocycled for 24 hours and then mounted in dental stone. A control group of 20 unrestored human mandibular molars was mounted in cold cure acrylic. Each tooth was tested in a Nene machine with a compressive load applied at 90 degrees to the occlusal surface at a crosshead speed of 5 mm/minute.There was no statistically significant difference between the experimental groups (P0.05), but the control group was significantly stronger (P0.001). Extension of core material into the coronal root canal system did not increase the fracture resistance of any of the experimental materials. Regression analysis of the results revealed no correlation between the volume of the pulp chamber and the load to fracture.

To determine the amount of fluoride released from several glass ionomer products [Fuji Cap II, Fuji Ionomer Type II, Ketac-Silver, Chelon-Silver, and Miracle Mix (hand-mixed and encapsulated)], and to compare them between triturated (5, 10, 15 seconds) encapsulated and hand-mixed glass ionomers.The amount of fluoride released at 1, 2, 3, 7, 14, 21 and 28 days after the start of immersion in deionized-distilled water at 37 degrees C was determined with a fluoride ion selective electrode. Rates of fluoride release and cumulative amounts of fluoride release were calculated.Each glass ionomer released the greatest amount of fluoride during the first 24-hour period. Although there was some variation between products, generally the hand-mixed specimens released significantly (P0.05) less fluoride than those prepared by mechanical trituration (10 and 15 seconds). The cumulative amounts of fluoride released from the mechanically triturated glass ionomers were significantly (P0.05) greater than the amounts released from the hand-mixed glass ionomers. No significant differences in the cumulative amounts of fluoride released from triturated materials were found among the different trituration times.

To evaluate the effect of topical fluoride gels on the microhardness of three glass ionomer cements.Cylinders of Ketac-Silver, Photac-Fil, and Fuji II LC were fabricated, stored in distilled water at 37 degrees C for 48 hours, and exposed to a neutral sodium fluoride gel (Karigel-N), and acidulated orthophosphoric acid gel (Karigel), and a stannous fluoride gel (Omni) at 37 degrees C for 36 hours. Knoop hardness was then recorded.Statistical analysis showed significant differences (P0.01) between groups related to material and treatment Ketac-Silver did not demonstrate significant differences in hardness, whereas exposure to APF decreased the Knoop hardness of Fuji II LC and Photac-Fil.

To measure and compare the fracture toughness of a multi-purpose resin composite, four light-cured glass ionomers, one light-cured resin ionomer, and two silver-containing glass ionomers.Ten specimens were fabricated for each of the eight materials: Herculite XRV, Fuji II LC, Photac-Fil, Vitrebond, Photac-Bond, VariGlass VLC, Ketac-Silver, and Miracle Mix. All materials were handled according to manufacturers' instructions during specimen fabrication, stored in 100% humidity for 2 weeks, and tested wet in a universal testing machine.The mean fracture toughness values (MPa . m(0.5) + or - S.D.) were: Herculite XRV = 1.17 + or - 0.09, Fuji II LC = 1.37 + or - 0.10, Photac-Fil = 1.27 + or - 0.08, VariGlass = 0.90 + or - 0.07, Vitrebond = 0.88 = or - 0.06, Photac-Bond = 1.09 + or - 0.09, Ketac-Silver = 0.51 + or - 0.08, and Miracle Mix = 0.30 + or - 0.07. There was a significant difference in the means (ANOVA P0.0001). Fuji II LC and Photac-Fil were significantly tougher than any of the other materials (Tukey's HSD test P0.01).

This study compared the clinical behavior of a glass ionomer (polyalkenoate) silver cermet, a posterior resin composite used with the "tunnel" technique, a posterior resin composite used with the "closed sandwich" technique, and a high-copper amalgam for restoring small, proximal surface carious lesions. Two dentists placed 86 restorations in the posterior permanent teeth of 26 adults treated at a dental hospital. Restorations were assessed at 6-month intervals over 2 years for gingivitis adjacent to them, the tightness of proximal contacts, occlusal wear, surface voids, roughness and cracking, surface and marginal staining, and marginal fracture. Small filling defects, surface voids and occlusal wear were obvious with the cermet material, with surface crazing and cracking present in 48% of the tunnel restorations. Two of the posterior resin composites, but none of the amalgam restorations, also failed. The cermet cannot be recommended as a long-term permanent restorative material in situations where it is likely to be subjected to heavy occlusal stresses and abrasive wear.

This study compared the clinical behavior of a glass ionomer silver cermet (Ketac-Silver), a posterior resin composite (Visio-Molar) used with the "sandwich" technique, and a high-copper amalgam (Dispersalloy) for restoring conventional Class I occlusal cavity preparations. Two dentists placed 116 restorations in the posterior permanent teeth of 35 adults treated at a dental hospital. Restorations were assessed at 6-month intervals over 2 years for bulk loss of material and occlusal wear, surface voids, roughness and cracking, surface and marginal staining, and marginal fracture. Losses of material and surface voids were obvious with the cermet material, with surface crazing or cracking being present in 33% of the restorations. The cermet cannot be recommended as a long-term permanent restorative material if the restorations are likely to be subjected to heavy occlusal stresses and abrasive wear.

This in vitro study evaluated the amount of fluoride released from glass ionomer-lined amalgam restorations over a period of 1 year. Class V cavities (2 x 2 x 7 mm) were prepared on the facial and lingual surfaces of 50 extracted human molars randomly distributed into 5 groups: Group 1: No restorations; Group 2: Dispersalloy amalgam alone; Group 3: same as Group 2 except 1 mm of Ketac-Silver was placed on the axial wall before amalgam insertion; Group 4: GC Lining/amalgam; and Group 5: Miracle Mix/amalgam. After restoration, each tooth was thermocycled (100x) at 5 degrees C and 55 degrees C with a dwell time of 30 seconds for baseline fluoride release levels. The teeth were placed in a polyethylene vial containing 4 ml of deionized water. At weekly intervals, each tooth was transferred to a fresh vial. Fluoride release was measured with a fluoride ion specific electrode for 10 consecutive weeks and then again at the end of 1 year. Calibration curves for low level measurements were prepared so the readings could be expressed in micrograms/ml F. At 1 year, fluoride released in micrograms/ml was: Group 1: less than 0.08; Group 2: less than 0.08; Group 3: 0.28; Group 4: 0.68; Group 5: 1.12. An ANOVA was used to evaluate the statistical difference between the groups. At the end of 1 year, measurable amounts of fluoride were recorded for all glass ionomer-lined groups with Miracle Mix and GC Lining releasing significantly more fluoride than Ketac-Silver (P less than 0.002).

This study examined the effect of fluoride-releasing core build-up materials upon both enamel and root demineralization in an artificial caries system. Thirty extracted human molars were randomly assigned to three treatment groups consisting of (1) conventional composite core build-up paste, (2) fluoridated core build-up paste and (3) glass cermet. Teeth were thermocycled 350 times between 5 degrees C and 55 degrees C using 30-second dwell times. Acid-resistant varnish was placed on the specimens to within 1 mm of the restoration and the teeth were subjected to an artificial-caries challenge at pH 4.2 for 72 hours. Teeth were then sectioned and the thin sections photographed using a polarized light microscope. Areas of the artificial-caries lesions were measured using a sonic digitizing pad. Mean lesion area (in arbitrary units from the digitizing pad) on enamel for Group 1 was 3.76 +/- 0.54; Group 2 was 2.53 +/- 1.17 and Group 3 was 2.32 +/- 0.68. Mean lesion area on root for Group 1 was 3.04 +/- 0.54; Group 2 was 2.34 +/- 0.58 and Group 3 was 2.51 +/- 0.53. ANOVA with Duncan's multiple range test of contrast indicates a significant difference (P less than 0.001) on both enamel (35 +/- 3%) and root (20 +/- 3%) between the non-fluoridated product and the two fluoridated products. There were no significant differences between Group 2 and 3.This artificial caries study indicates that a fluoride-releasing core material may be of value in preventing demineralization of tooth structure adjacent to the restorative core material.

The purpose of this article is to present a case report of the dental care for permanent teeth that were originally considered "non-restorable". The temporary placement of stainless steel crowns was completed, followed by traditional endodontic therapy. The crowns were used as build-up matrices, access being prepared in the occlusal of the crown. Glass ionomer silver was then placed, followed by marginal finishing. Although this report is an isolated case, and is considered as temporary treatment, there may be indications to consider this technique for clinical care, on an individual basis.

This in vitro study examined the marginal integrity of Class II lesions using three restorative techniques. Class II preparations (MO and DO) were placed in 30 teeth. Half had the cervical margin placed 1 mm below the CEJ, the remaining had cervical margins 2 mm above the CEJ. The preparations were randomly restored using three techniques: 1) Glass ionomer liner and posterior composite resin; 2) Glass ionomer silver cermet placed in the proximal box to the contact area and the remainder restored with posterior composite resin; 3) Glass ionomer silver cermet only. All 30 teeth were loaded with 17 kg, thermocycled and stored in 37 degrees C solution for 30 days. The teeth were again loaded, immersed in 2% basic fuchsin solution for 24 hours, sectioned and photographed. Microleakage was calculated, according to the depth of dye penetration. Results demonstrated Techniques 1 and 2 to have less marginal leakage than Technique 3 when preparations remained in enamel and Techniques 1, 2 and 3 when preparations were below the CEJ. The chi-square test indicated a statistically significant difference between restoration technique and marginal microleakage (P less than 0.001).

The objective of this study was to determine the shear bond strength of dental amalgam bonded to dentin with adhesives. Four groups of 15 permanent posterior teeth were used in this study. The occlusal enamel of the teeth was removed to produce a flat dentin surface. The teeth were embedded in phenolic rings with acrylic resin. Vinyl polysiloxane ring molds 4 mm thick with 4.5 mm circular openings were attached to the exposed dentin surface. Adhesives applied to the dentin surfaces prior to amalgam placement and condensation included: Amalgambond, a 4-META/TBB-MMA, HEMA based system (A), Panavia EX, a modified phosphate ester of Bis-GMA luting system (P), and Ketac-Cem, a glass ionomer luting cement (K). A dentin bonding agent and composite resin restoration system (Scotchbond 2/Silux Plus) was included for comparison. The specimens were stored in 37 degrees C water for 7 days prior to testing. Shear bond tests were done in an Instron machine at a crosshead speed of 0.02 inches per minute. The data were analyzed by ANOVA at 5% level of significance. The differences in shear bond strengths of the four test groups were not statistically significant (P = 0.115). Fracture patterns of the bonded amalgams, examined by SEM, were adhesive in appearance for Groups A and K and cohesive for Group P.

Chelon Silver (C), Ketac-Silver Aplicap (K), Miracle Mix (M) silver-reinforced glass ionomers, and Valiant PH.D were evaluated as in vitro repair materials for cores. The core materials were placed in a 6 x 3 mm mold and stored at 37 degrees C at 100% RH for 24 hours. The cores were roughened with a coarse diamond. Five samples were conditioned (T) with Dentin Conditioner for 20 seconds, whereas another 5 samples were untreated (U). The cores were then repaired with C, K and M and subsequently tested after additional storage for 24 hours. Bond strength (MN/m2) was measured in tension using an inverted cone bond test at a crosshead speed of 0.05 cm/min. Mean bond strengths (S.D.) for the three repair materials when averaged over the three glass ionomer cores were: K, 5.0 (1.2); M, 3.4 (1.2) and C, 2.7 (1.5) for condition U; and M, 4.2 (1.1); K, 3.4 (1.2); and C, 3.1 (1.0) for condition T, where M, K and C were the repair materials. The Tukey intervals at the 95% level were 0.7 among materials and 0.5 between treatments. Bond strength of repaired amalgam was only successful with M, 0.9 MN/m2. Bond strengths to untreated silver-reinforced glass ionomer cores were higher with K used as a repair material.

This study evaluated the amount of fluoride released from glass ionomer-lined amalgam restorations. 50 human extracted molars were divided into five groups of 10 teeth each. Group 1: No restorations. Group 2: Class V cavities (2 x 2 x 7 mm) were made on the facial and lingual surfaces and restored with Dispersalloy amalgam. Group 3: Same as Group 2 except 1 mm of Ketac-Bond glass ionomer cement (GIC) was placed on the axial wall before amalgam insertion. Group 4: Same as Group 2 except 1 mm of Chelon-Silver glass ionomer cement (GIC) was placed on the axial wall before amalgam insertion. Group 5: Same as Group 2 except 1 mm of Ketac-Silver GIC was used before amalgam insertion. Before any treatment, all samples were placed in polyethylene vials with 4 ml of deionized water and thermocycled (100x) for baseline fluoride release levels. After restoration, each tooth was placed in a vial with 4 ml of fresh deionized water. At weekly intervals, each tooth was removed from its aqueous medium and transferred to another vial containing 4 ml of deionized water. Fluoride release was measured four times at weekly intervals with an Orion #9609 fluoride-ion electrode. At one week, Ketac-Bond released significantly more fluoride than Ketac-Silver (P less than 0.01) which released significantly more fluoride than Chelon-Silver (P less than 0.01). At four weeks, there was no significant difference in fluoride release between Chelon-Silver and Ketac-Silver, but Ketac-Bond released significantly more fluoride than either of the other materials (P less than 0.01).