PubMed · 6586417
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R Naujoks. 1984. [New developments from caries research--benefit for practice!?].. https://pubmed.ncbi.nlm.nih.gov/6586417/
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STATEMENT OF PROBLEM: There are no long-term data on Dicor glass-ceramic restoration survival in the human oral cavity and the effect that different technical and clinical variables have on survival. PURPOSE: This prospective study examined the relationship of different clinical parameters on the survival of Dicor glass-ceramic restorations in the human oral cavity. MATERIAL AND METHODS: A total of 417 subjects (from 17 to 91 years of age) participated. All subjects required single unit fixed prosthodontics in any area of the mouth and/or 3-unit fixed partial dentures or cantilevered anterior restorations. They were offered the option of a gold or conventional metal-ceramic restoration, or a Dicor restoration with potentially improved esthetic results, better wear characteristics, and diminished oral plaque accumulation. Overall survival of the restorations was determined and the effect of various clinical parameters evaluated with Kaplan-Meier survival curves. Log rank tests were used to determine statistically significant differences among parameters. RESULTS: For the 1444 units placed, 188 failures were recorded. Total time at risk for the units was 7319 years providing an estimated risk of 2.45% per year. Probabilities of survival of "typical" acid-etched Dicor and nonacid-etched Dicor restorations were 76% and 50%, respectively, at 14.1 years (P <.001). Probabilities of survival of typical acid-etched and nonacid-etched Dicor complete coverage restorations were virtually identical to those observed in the full data set. There was a 2.2 times greater risk of failure associated with the use of nonacid-etched Dicor complete coverage than acid-etched restorations (P <.01). Complete coverage restoration survival was highest in the incisor region and decreased to the molars in both arches. Second molars showed the highest failure rate. No complete coverage restorations failed on lateral incisors during the entire study. Probability of survival of a typical acid-etched Dicor complete coverage restoration in male subjects was 71%, and 75% for female subjects at 14.1 years (P <.01). The major difference appeared to be due to a greater failure rate in the maxillary arch of the male. Survivor functions of acid-etched Dicor complete coverage restorations for subjects in <33 years, 33 to 52 years, and 52 years age groups were 88% at 9 years, 62% at 14 years, and 82% at 14 years, respectively. CONCLUSIONS: Dicor restorations can survive successfully over time with certain reservations. Long-term survival improved significantly when restorations were acid-etched before luting. Complete coverage restoration failures per year decreased from molars to incisors in both arches, suggesting that complete coverage restorations on molars represented a serious risk. No Dicor complete coverage restoration on lateral incisors failed during the study. Restorations failed less often in female than male subjects.
The purpose of this study was to determine the shear bond strengths of orthodontic brackets bonded with one of three methods: (1) a glass ionomer adhesive with a 20% polyacrylic acid enamel conditioner; (2) a composite resin adhesive used with 37% phosphoric acid etchant and a conventional primer; or (3) the same composite resin used with an acidic primer that combines the etchant with the primer in one application. The brackets were bonded to the teeth according to one of three protocols. Group I teeth were etched with 37% phosphoric acid and bonded with Transbond XT (3M Unitek, Monrovia, Calif) following the manufacturer's instructions. Group I acted as the control group. Group II teeth were etched with an acidic primer (Clearfil Liner Bond 2. J.C. Moritta Kuraway, Japan) that contains both the acid (Phenyl-P) and the primer (HEMA and dimethacrylate) and was placed on the enamel for 30 seconds; the adhesive used to bond the brackets was Transbond XT as in Group I. Group III teeth were etched with 20% polyacrylic acid and the brackets were bonded with Fuji Bond LC (G.C. America, Chicago, Ill). A steel rod with one flattened end was attached to the crosshead of a Zwick test machine (Zwick GmbH & Co, Ulm, Germany). An occlusogingival load was applied to the bracket, producing a shear force at the bracket-tooth interface. The results indicated that the resin/phosphoric acid adhesive system (control group) provided the strongest shear bond strength x = 10.4 +/- 2.8 MPa). The glass ionomer adhesive system provided a significantly lower bond strength (x = 6.5 +/- 1.9 MPa). The least shear bond strength was present when the acidic primer was used with an orthodontic adhesive (x = 2.8 +/- 1.9 MPa). In the present study, the use of either a fluoride-releasing glass ionomer or an acidic primer in combination with an available orthodontic composite adhesive resulted in a significantly reduced shear bond strength when compared with that of the conventional composite resin adhesive system. At the present time, the orthodontist and the patient are better served by using phosphoric acid/composite resin adhesive system or other equivalent systems that provide a clinically reliable bond strength between the bracket, the adhesive, and the enamel surface.
Shear bond strength of Concise (a composite resin adhesive) and Fuji Ortho LC (a light-cured resin-reinforced glass ionomer cement) bonded to extracted teeth was tested under different bonding conditions: (1) Concise/etched/dry (2) Fuji/etched/dry (3) Fuji/etched/wet (4) Fuji/unetched/dry (5) Fuji/unetched/wet. Concise/etched/dry and Fuji/etched/dry groups showed comparable mean shear bond strength (10.5 and 8.2 MPa, respectively); the other three groups had considerably lower values. The difference between Fuji/etched/dry and Fuji/etched/wet was not statistically significant. The site of bond failure was between bracket and adhesive in all etched groups and between adhesive and enamel in the unetched groups. We conclude that (1) enamel surface etching is required for Fuji Ortho LC to achieve optimum bond strength, (2) moisture does not affect bond strength of Fuji Ortho LC significantly.