ABSTRACT
Background: The retention of cement-retained implant-supported restorations can be affected by surface treatments such as anodizing. This study aimed to assess the effect of the anodization of titanium abutments on their tensile bond strength to implant-supported lithium disilicate (LDS) all-ceramic crowns. Materials and Methods: This in vitro, experimental study was conducted on 26 straight abutments in two groups of anodization and control. In the anodization group, seven flat 9 V batteries connected in series were used to generate 64 V energy. A glass container was filled with 250 mL of distilled water, and 1 g of trisodium phosphate was added to it to create an electrolyte solution. The anode was then disconnected and the abutment was rinsed with acetone and deionized water. The surface roughness of abutments was measured by a profilometer. The abutments were scanned by a laboratory scanner, and maxillary central incisor monolithic crowns were fabricated by inLab SW18 software. The crowns were seated on the abutments and temporarily cemented with TempBond. They were then incubated in artificial saliva and subjected to 5000 thermal cycles. The tensile bond strength of crowns was then measured. Data were analyzed by the Student's t-test and Mann-Whitney U-tests (α =0.05). Results: The mean bond strength was significantly higher in anodized abutments (P = 0.003). The surface roughness of anodized abutments was slightly, but not significantly, higher than that of the control group (P > 0.05). The frequency of adhesive failure was almost twice higher in anodized abutments. Conclusion: Anodization of titanium abutments significantly improved their tensile bond strength to implant-supported LDS all-ceramic crowns.
ABSTRACT
STATEMENT OF PROBLEM: The conventional method of fabricating removable partial denture (RPD) patterns is a time-consuming, expensive, and complex process, and the success of the treatment depends on the fit of the framework. Questions still remain as to whether the 3D-printing method is an acceptable procedure compared with the conventional method. PURPOSE: The purpose of this in vitro study was to compare the fit of RPDs cast from 3D-printed frameworks and conventionally fabricated RPDs according to the gaps between the framework and the reference model. MATERIAL AND METHODS: A metal reference model was made from a Kennedy class III modification 1 maxillary typodont. For the conventional group (n=9), impressions were made from the metal cast. Cobalt-chromium frameworks were cast with the conventional method. For the digital group (n=9), the metal cast was scanned with a laboratory scanner, and the RPD was designed in the 3Shape platform. The standard tessellation language (STL) file of the design was downloaded to a 3D printer (Hunter DLP), and 9 resin frameworks were printed. These frameworks were invested and cast in the same dental laboratory as the first group. Gap measurement was assessed vertically with a superimposition software program (Geomagic Control X), and additional measurements were assessed under rests, reciprocal arms, and a 2.2-mm box under the major connector. The independent t test was used for determining the results and statistical analysis between groups. The paired t test was used for statistical analysis within groups (α=.05 for all tests). RESULTS: No significant differences (P>.05) were observed in the mean ±standard deviation in overall fit according to the gaps in the conventional group (103 ±18 µm) and those in the digital group (109 ±21 µm). The biggest gap (poorest fit) was observed in the 2.2-mm box under the major connector (115 ±6 µm). CONCLUSIONS: Both conventional and 3D-printing methods showed clinically acceptable fits. Further clinical studies with a larger specimen size and long-term follow-up are needed.
