1876
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Tay FR, Gwinnett AJ, Pang KM, Wei SH. Variability in microleakage observed in a total-etch wet-bonding technique under different handling conditions. J Dent Res 1995; 74:1168-78. [PMID: 7790594 DOI: 10.1177/00220345950740050501] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Using a stereoscopic clearing protocol and scanning electron microscopy, we investigated the extent and nature of microleakage in a total-etch, current-generation dentin adhesive by a wet-bonding technique under different handling conditions. The hypotheses were that inadequate light curing of the primer or incomplete drying of the primer solvent might adversely affect the sealing ability of an acetone-containing adhesive system. The study consisted of three experimental groups: (I) a control group with an adequate light source and with the primer solvent completely dried; (II) an "inadequate-light" group; and (III) an "incomplete evaporation of primer solvent" group. The extent of microleakage after silver staining and clearing of the specimens was scored based on a modified five-point scale. Nonparametric statistical analysis (Kruskal-Wallis ANOVA) followed by a multiple comparison test (Dunn test) indicated significant differences among the three groups (p < 0.05). SEM examination of the restorative interface revealed that microleakage appeared to be initiated from the bonding resin-hybrid layer interface in all three groups, representing the weak link in the adhesive system. In addition, microleakage was characterized by 5 zones, each delineating a stage in a continuous array of progressively deleterious microleakage patterns variously distributed among the three groups. It was suggested that, while the bonding resin-hybrid layer interface represented the intrinsic weakness in an already much improved dentin adhesive, extrinsic factors such as the adequacy of the curing light and, more importantly, complete removal of the primer solvents can and should be avoided to preserve the structural integrity of the marginal seal.
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1877
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Fanning DE, Wakefield CW, Robbins JW, Bagley AL. Effect of a filled adhesive on bond strength in three dentinal bonding systems. GENERAL DENTISTRY 1995; 43:256-62. [PMID: 8940582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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1878
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Bott B, Hannig M. Optimizing Class II composite resin esthetic restorations by the use of ceramic inserts. JOURNAL OF ESTHETIC DENTISTRY 1995; 7:110-7. [PMID: 8527197 DOI: 10.1111/j.1708-8240.1995.tb00727.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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1879
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Thonemann B, Federlin M, Schmalz G, Hiller KA. Resin-modified glass ionomers for luting posterior ceramic restorations. Dent Mater 1995; 11:161-8. [PMID: 8600007 DOI: 10.1016/0109-5641(95)80012-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVES Until recently, esthetic inlay restorations in posterior teeth have been limited to cavities surrounded by enamel. Dentin adhesive systems in combination with luting composites and light-cured resin-modified glass ionomer cements offer a possibility for bonding ceramic inlays to cavities when the cervical margin is in dentin. This study was designed to compare in vitro marginal integrity of ceramic inlays bonded to dentin to restorations placed in cavities with margins located entirely in the enamel. METHODS In the present in vitro study, the sealing abilities of a dentin bonding agent/luting composite combination (Syntac/Dual Cement, Vivadent) and resin-modified glass ionomers (Photac Fil, Photac Bond, ESPE; Dyract, De Trey Dentsply; Fuji II LC, GC Dental Industrial Corp.; and Vitremer, 3M Dental Products) used as luting agents in cavities extending beyond the cemento-enamel junction, were compared to the sealing abilities of a conventional luting composite (Vita Cerec Duo Cement, Vita) in cavities within sound enamel. SEM analysis and dye penetration were performed to evaluate marginal integrity at the cervical cavity margins. RESULTS The dentin bonding agent/luting composite combination (Syntac/Dual Cement) rendered a marginal seal within the dentin similar to the quality obtained with the conventional luting procedures within sound enamel. When three out of the five resin-modified glass ionomers were used as luting agents (Dyract, Fuji II LC and Vitremer), the results were comparable to those reported for the dentin bonding agents and the conventional method. SIGNIFICANCE Light-cured resin-modified glass ionomer cements may be considered as an alternative to dentin bonding agents when the cavity margins of ceramic inlay restorations are within the dentin. However, further studies, e.g., wear resistance, must be performed.
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1880
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Kidd EA, Joyston-Bechal S, Beighton D. Marginal ditching and staining as a predictor of secondary caries around amalgam restorations: a clinical and microbiological study. J Dent Res 1995; 74:1206-11. [PMID: 7540634 DOI: 10.1177/00220345950740051001] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Caries at the margins of restorations is difficult to diagnose. In particular, the relevance of both marginal ditching and staining around amalgam restorations is unclear. This clinical study questions the relevance of marginal ditching and color change to the level of infection of the dentin beneath the margins of amalgam restorations. Clinically visible sites (330) on the tooth/restoration margin were selected on 175 teeth. The enamel adjacent to each site was noted as stained (a grey discoloration) or stain-free. One hundred and seventy-eight sites were clinically intact, 83 sites had narrow ditches (< 0.4 mm), and at 49 sites, wide ditches were present (> 0.4 mm). Twenty sites with frankly carious lesions were also included. Plaque was sampled at the tooth-restoration margin, and the dentin was sampled at the enamel-dentin junction below each site. Samples were vortexed, diluted, and cultured for total anaerobic counts, mutans streptococci, lactobacilli, and yeasts. Plaque samples showed that margins with wide ditches (> 0.4 mm) harbored significantly more bacteria, mutans streptococci, and lactobacilli than did clinically intact margins and margins with narrow ditches. There were no significant differences in the degree of infection of the dentin beneath clinically intact restorations and those with narrow ditches, but samples associated with wide ditches and carious lesions yielded significantly more bacteria, mutans streptococci, and lactobacilli. The color of the enamel adjacent to the sample site was irrelevant to the level of infection of the dentin beneath the filling margin, provided a frankly carious lesion was not present.(ABSTRACT TRUNCATED AT 250 WORDS)
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1881
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Kataia MA, Seif RE, el-Sayed JM, Ezzat KM. Dentin wall adaptation of multiphase versus temperature thermoplasticized gutta-percha. A scanning electron microscopic study. EGYPTIAN DENTAL JOURNAL 1995; 41:1129-1136. [PMID: 9497649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
An in-vitro study was designed to compare dentin wall adaptation of Multiphase gutta-percha root canal obturation technique versus high temperature thermoplasticized gutta-percha (Obtura) in the presence and absence of smear layer. Forty single rooted teeth with straight canals were used. After decapitation roots were divided into two equal groups. Group (I) received final irrigation with EDTA and Sodium hypochlorite (NaOCI) to remove the smear layer, while roots in Group (II) were irrigated with NaOCI alone. Each group was then subdivided into two subgroups to represent the two filling techniques. Teeth were sectioned longitudinally and viewed under scanning electron microscope. Multiphase gutta-percha showed excellent adaptation to canal wall, specially in the absence of smear layer and displayed a homogeneous mass with little amount of voids than the Obtura system.
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1882
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Schmalz G, Federlin M, Reich E. Effect of dimension of luting space and luting composite on marginal adaptation of a class II ceramic inlay. J Prosthet Dent 1995; 73:392-9. [PMID: 7783020 DOI: 10.1016/s0022-3913(05)80337-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This study evaluated the in vitro marginal quality at the interproximal cervical margin of class II Cerec restorations. Marginal quality was evaluated separately by (1) SEM analysis before and after simultaneous thermocycling and mechanical loading for the integrity of the restoration surface and (2) dye penetration after thermocycling and mechanical loading to evaluate the strength of the bond within the depth of the cavity. The results reveal that marginal integrity is influenced by the width of the luting space and the luting composite. With a luting space of 100 microns, marginal quality with as little as 3% to 14% loss of adhesion can be obtained. Luting spaces greater than 100 microns can partially be compensated by the luting composite. For Cerec inlays, highly filled luting composites with a high viscosity are recommended.
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1883
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Gwinnett AJ, Yu S. Effect of long-term water storage on dentin bonding. AMERICAN JOURNAL OF DENTISTRY 1995; 8:109-11. [PMID: 7546480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE To determine the effect of long term water storage on assembly bond strength and interfacial integrity of resin composite bonded to dentin. MATERIALS AND METHODS Four groups, each containing 10 molar teeth, were established to measure the shear strength of All-Bond 2 and Amalgambond bonded P50 resin composite assemblies at 24 hours and after 6-month water storage at 37 degrees C. An additional four groups of similarly bonded Class V restorations were subjected to the same immersion periods. Marginal leakage was determined using eosin dye and the restoration interface was observed using polyvinyl siloxane impressions to determine gap location. RESULTS The shear strength values (MPa) for All-Bond 2 were 32.68 +/- 7.12 and 23.29 +/- 5.77 at 24 hours and 6 months respectively. The mean values for Amalgambond were 26.03 +/- 5.94 and 12.90 +/- 6.90. The difference between the values at different immersion times was statistically significant (P < 0.05). There was no evidence of dye leakage in any of the teeth. No gaps were found at the margins of the restorations correlating with the absence of microleakage. Gaps were found commonly at the floor of the Amalgambond restorations.
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1884
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Moon PC. Class II posterior composites--ways to reduce bond stress and microleakage by using low modulus materials. VIRGINIA DENTAL JOURNAL 1995; 72:12-4. [PMID: 9540749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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1885
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Hata G, Kawazoe S, Toda T, Weine FS. Sealing ability of thermoplasticized gutta-percha fill techniques as assessed by a new method of determining apical leakage. J Endod 1995; 21:167-72. [PMID: 7673814 DOI: 10.1016/s0099-2399(06)80559-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
One hundred fifty-nine extracted single-rooted maxillary human teeth were instrumented and randomly divided into nine groups of 17 teeth each and 6 control teeth. Experimental groups were obturated with Thermafil, Obtura II, Ultrafil Regular Set gutta-percha, and Ultrafil Firm Set gutta-percha, each with or without root canal sealer. A control group was obturated using the lateral condensation technique and sealer. Teeth were immersed in a resorcinol-formaldehyde resin for 5 days at 4 degrees C, and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were then sectioned horizontally at 1.5, 2.5, and 3.5 mm from the anatomical apex, and examined under a stereomicroscope at x25 magnification. The resin filled the spaces in the gap between the canal wall and the gutta-percha and this was measured at each of the three levels. The ratio of the area of the resin to the total area of the canal was obtained as the mean leakage area. The results showed no significant difference in the mean leakage area at the same level for the different obturation materials. However, the leakage was significantly less for all materials when root canal sealer was used.
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1886
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Abstract
A method was developed for measuring presence, location and extent of interfacial contraction gaps of resin-cemented ceramic inlays in dentin cavities. Cylindrical ceramic inlays were cemented using one of 12 commercially available resin composite cements to make a film thickness of 200-microns. Cross-sections revealed absence of marginal gaps but contraction gaps occurred at all dentin-cement interfaces at the cavity floors and ranged from 1.6 to 7.1 microns. This was equivalent to 0.8-3.5% of the cement film thickness and was 3-10 times greater than the wall-to-wall contraction in percent observed when resin composites are used as filling materials in 3-5 mm butt-joint dentin cavities. The results support the theory that contraction gaps developing adjacent to thin films of resin cements reach a size equivalent to the cement film thickness multiplied by the volumetric polymerization shrinkage of the cement.
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1887
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Freedman G. Ultraconservative rehabilitation. DENTISTRY TODAY 1995; 14:44, 46, 48-51. [PMID: 9540673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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1888
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el-Karaksi AO. Influence of laser enamel and dentine etching on marginal integrity of porcelain laminate veneers. EGYPTIAN DENTAL JOURNAL 1995; 41:1095-103. [PMID: 9497645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This investigation evaluated the effect of laser etching and acid etching techniques on the marginal leakage Vitadur N porcelain laminate veneers bonded either entirely on enamel, or with cervical margin located on root dentine of prepared extracted maxillary central incisors. Two different composite resin luting systems (light cured, or light and chemical cured) were used and compared. The bonded specimens were thermocycled and by employing the Standard dye penetration technique the leakage was scored from cervical and incisal margins. The least marginal leakage was observed beneath laminate veneers bonded entirely on enamel. Laser etching improved the sealing qualities of veneers with cervical margins on root dentine below the CEJ. Statistically insignificant differences were observed with the use of the two different composite resin luting systems.
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1889
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Yokoi K, Miyaji H, Itoh K, Hisamitsu H, Wakumoto S. Water content in experimental dentine primers to minimize the contraction gap width of a light-cured resin composite. J Dent 1995; 23:117-21. [PMID: 7738268 DOI: 10.1016/0300-5712(95)98978-c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
OBJECTIVES The effect of water content in experimental dentine primers consisting of an aqueous solution of either glyceryl methacrylate (GM) or hydroxyethyl methacrylate (HEMA), and in experimental self-etching dentine primers composed of methacryloxyethyl hydrogen phenyl phosphate (Phenyl-P), was evaluated by measuring the wall-to-wall polymerization contraction gap width of a commercial light-activated resin composite filled in a cylindrical dentine cavity prepared in an extracted human molar. METHODS A commercial light-cured dentine bonding agent was applied to the cavity after cleaning with EDTA and priming with either GM or HEMA, or after self-etching priming by Phenyl-P diluted in either GM or HEMA solution. RESULTS In the GM and HEMA solutions, the gap width was minimized when the water content was 65 wt% even though gap formation could not be prevented by HEMA solution. With the self-etching dentine primers, gaps could not be observed under the light microscope with 16 wt% Phenyl-P diluted in 35 wt% GM or HEMA or with 20 wt% Phenyl-P diluted in 20 wt% GM or HEMA. CONCLUSION The water content in both the experimental dentine primers and the self-etching dentine primers which yielded the minimum contraction gap width for the resin composite in the dentine cavity was approximately 60 wt%.
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1890
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Sherif AH. Influence of linear expansion of two different non metallic core materials upon cervical marginal accuracy of full veneer crowns. EGYPTIAN DENTAL JOURNAL 1995; 41:1121-8. [PMID: 9497648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The effect of water sorption and linear expansion of two different non metallic core materials: 1) Composite and 2) Reinforced glass ionomer on the cervical marginal seating of cast metal crowns was investigated in this study. Thirty freshly extracted sound mandibular molar teeth were used in this study. The teeth were machined cut to simulate average dimensions of a prepared lower second premolar tooth with chamfer finish line. The teeth were decoronated 2 mm above the finish line then specially prepared to receive equal volumes of either pin retained composite or pin retained reinforced glass ionomer. The teeth after that were restored with full coverage metal crowns. Ten of each type of core samples were immersed in 37 degrees C normal saline while the remaining samples were maintained dry (control). The vertical cervical marginal accuracy of the crowns were microscopically measured with 1 micron accuracy before immersion and after 6, 12 hours and every day of the following ten days of saline immersion. The statistical analysis of the results revealed that composite core immersed in saline solution at 37 degrees C possessed dimensional instability with the maximum linear change between the first and the second day. Also the reinforced glass ionomer core showed no effect upon the cervical marginal seating of the overlying full coverage cast metal crown.
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1891
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Omurtay S, Aslan Y. Marginal reservoirs for multiunit castings. QUINTESSENCE INTERNATIONAL (BERLIN, GERMANY : 1985) 1995; 26:257-66. [PMID: 7568745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This study measured the distortion of one-piece base metal four-unit fixed partial dentures and recorded the effect of positioning "marginal reservoirs" on the wax patterns. Standard wax patterns were made in a special three-piece stainless steel mold. Twenty anterior prostheses were cast: 10 for the experimental group and 10 for the control group. The prostheses were cast in a nickel-chromium alloy and were measured with a traveling microscope with a micrometer scale. Premarked points were designated on gingivoaxial line angles for buccolingual and mesiodistal distances and diameters to record marginal discrepancies of specimens with or without marginal reservoirs. Castings with marginal reservoirs distorted significantly less than did the control fixed partial dentures.
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1892
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Grossman ES, Witcomb MJ, Matejka JM. Influence of amalgams, bases, and varnish on seal composition at restoration tooth interfaces. J Prosthet Dent 1995; 73:290-8. [PMID: 7760280 DOI: 10.1016/s0022-3913(05)80208-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Eighty extracted, noncarious premolars were restored with one of 20 different combinations of restorative materials: a high- or low-copper amalgam, unlined or lined with one of five bases, and varnished or unvarnished. The teeth were aged in 1% NaCl and after 3 months and 1 year the seal material deposited on the cut tooth cavity surface and the surface of the amalgam restoration was analyzed by use of energy dispersive x-ray analysis. Atomic weight percentages of marginal seal elements were statistically examined with ANOVA and Tukey's test with significance set at p < 0.05. The results indicated that only one type of seal was formed centered around tin. More marginal seal material was present in the 1-year specimens. Restoration materials used affected the deposition rate of marginal seal material. Low-copper amalgam-restored teeth formed more seal material with significantly greater amounts of chlorine and tin. Less marginal seal material was found in varnished cavities. A calcium hydroxide base produced a thick marginal seal with a significantly different composition of elements compared with the unlined and zinc-based specimens. Tin in Poly-F Plus polycarboxylate cement did not significantly increase the tin content of the marginal seal. Base materials can play a role in determining crevice pH. The findings have bearing on improved longevity of amalgam restorations.
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1893
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Baumgardner KR, Taylor J, Walton R. Canal adaptation and coronal leakage: lateral condensation compared to Thermafil. J Am Dent Assoc 1995; 126:351-6. [PMID: 7897104 DOI: 10.14219/jada.archive.1995.0180] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In a comparison of different obturating techniques and materials, lateral plus vertical compaction of gutta-percha had the least coronal leakage. Using increments of gutta-percha is indicated for tapered canals and those with irregular anatomy.
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1894
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Mertz-Fairhurst EJ, Adair SM, Sams DR, Curtis JW, Ergle JW, Hawkins KI, Mackert JR, O'Dell NL, Richards EE, Rueggeberg F. Cariostatic and ultraconservative sealed restorations: nine-year results among children and adults. ASDC JOURNAL OF DENTISTRY FOR CHILDREN 1995; 62:97-107. [PMID: 7608378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The objective of this clinical study was to evaluate the long-term efficacy of placing sealed posterior composite restorations for arresting active caries. The tooth preparation for this bonded and sealed restoration was limited to placing a bevel in the enamel only, without the removal of the carious lesion. The radiographic and clinical performance of these ultraconservative sealed composite restorations placed over caries (CompS/C) was compared over a period of nine years with: 1) ultraconservative, localized sealed amalgam (AGS) restorations with no extension for prevention, and 2) traditional, unsealed amalgam restorations (AGU) with the usual extension for prevention outline form. Sealant retention with > 50 percent to 100 percent of the margins occurred in 64 percent of CompS/C and 82.5 percent of AGS restorations. After nine years the cumulative failure rates were 16 percent for CompS/C, 2.5 percent for AGS, and 17.1 percent for AGU restorations. Thus, the clinical performance of CompS/C restorations was slightly superior to that of the traditional AGU restorations. The AGS restorations were definitely superior to the traditional AGU restorations and to the CompS/C restorations in both children and adults alike. Complete sealant retention over CompS/C and AGS restorations was equivalent between children and adults (P = 0.14 and 0.74, respectively). A higher percentage of open margins in CompS/C restorations was seen, however, in children (17.4 percent) than adults (1.94 percent). This study has shown that Class I caries can be arrested by the CompS/C restoration.
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1895
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1896
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Quinn F. An in-vitro investigation into the sealing ability of two fourth generation dentine bonding agents and two resin modified glass polyalkenoate restoratives. THE EUROPEAN JOURNAL OF PROSTHODONTICS AND RESTORATIVE DENTISTRY 1995; 3:119-25. [PMID: 8603154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To determine the in-vitro sealing ability of two resin modified glass polyalkenoate cements and two fourth generation dentine bonding systems, fifty mixed class V cavities were filled with each material and evaluated for leakage. At enamel margins, no significant differences in leakage extent was noted; however, at cemental margins the two resin modified glass polyalkenoates performed significantly better than the resin based systems. Crazing was frequently noted on enamel margins with both glass polyalkenoate materials. Surface application of unfilled glaze did not affect the leakage at either enamel or cemental margins for one of the polyalkenoate restorative materials.
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1897
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Hovav S, Holan G, Lewinstein I, Fuks AB. Microleakage of class 2 Superbond-lined composite restorations with and without a cervical amalgam base. Oper Dent 1995; 20:63-7. [PMID: 8700773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The purposes of the present study were: 1) to assess the microleakage at the cervical margin of Superbond-lined composite restorations with and without a cervical amalgam base and compare the results to cervical margins of composite restorations lined with Scotchbond 2, and 2) to compare the quality of the occlusal margins of Superbond-lined P-50 restorations with those bonded with Scotchbond 2. Forty-eight class 2 cavities were prepared in extracted or exfoliated primary molars. The teeth were randomly divided into three groups and restored as follows: Group A, amalgam + Superbond + P-50 (sandwich); Group B, Superbond + P-50; Group C, Scotchbond 2 + P-50 (control). Marginal leakage was assessed by the degree of dye penetration on sections of the restored teeth. The occlusal margins presented no or minimal leakage (degrees 0 and 1) in 53% of Group A restorations, 60% of Group B, and 44% of Group C. These differences were not statistically significant (P<0.05). The cervical margins showed moderate to severe dye penetration (degrees 2 and 3) in 94% of Group A, 47% of Group B, and 87% of Group C. These differences were statistically significant (P<0.05). The amalgam/Superbond/composite interface exhibited no leakage in 70% of the restorations. Although marginal leakage was not completely eliminated, Superbond exhibited significantly less leakage (P<0.05) at the cervical margins than Scotchbond 2 or amalgam with Superbond.
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1898
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Abstract
A marginal gap exists between the amalgam restoration and the cavity walls. At this interface, there is a constant percolation of fluid containing ions, molecules and bacteria. With time, corrosion products of the amalgam components seal the gap at the amalgam/tooth interface. The corrosion processes for conventional and high copper amalgam and factors affecting the corrosion deposits are reviewed. Better amalgam adaptation to the cavity walls improves the chances of sealing the restoration by corrosion products. The effectiveness of cavity varnish in preventing microleakage until corrosive deposits are formed is discussed.
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1899
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Sjögren G. Marginal and internal fit of four different types of ceramic inlays after luting. An in vitro study. Acta Odontol Scand 1995; 53:24-8. [PMID: 7740927 DOI: 10.3109/00016359509005940] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The marginal and internal fit of four different types of ceramic inlays--Cerec, Celay, Empress, and Vita In-Ceram Spinell--was determined after they had been luted on extracted premolars. For the Cerec inlays sharp and U-shaped proximal box shapings were also compared. There was no statistically significant difference either in the proximal fit or in the gingivoproximal fit between the four inlay systems studied, with the exception of the Cerec inlays made for preparations with sharp proximal boxes, which had wider marginal gaps. At the occlusal margins a significant-principle order of the gap width was established. The best internal fit was recorded for the Celay inlays, whereas there was no significant difference in the internal fit between the other systems. For the Cerec inlays the U-shaped proximal box shaping improved the marginal accuracy all around the restoration.
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1900
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Sidhu SK, Watson TF. Resin-modified glass ionomer materials. A status report for the American Journal of Dentistry. AMERICAN JOURNAL OF DENTISTRY 1995; 8:59-67. [PMID: 7546477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The resin-modified glass ionomer materials are hybrid materials of traditional glass ionomer cement with a small addition of light-curing resin, and hence exhibit properties intermediate to the two, with some characteristics superior to conventional glass ionomer materials. Generally, they have the advantages of both such as adhesion to tooth structure, esthetics, fluoride release and rapid hardening by visible light. Issues surrounding other physical properties, such as the mechanism of adhesion, sensitivity to water, long-term wear and strength, need to be addressed and substantiated. There are other considerations, which are not features of the conventional materials, but are of importance with the resin-modified glass ionomer cements i.e. light-curing, which require further research to provide evidence of their behavior. The future for this group of materials is unknown, but the currently available materials appear to be promising.
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