Abstract
Aim Vertical marginal discrepancy (VMD) influences the success of implant-supported restorations. However, there is little literature that has investigated the influence of geometry and cementing agent on changes in VMD of metal copings on implant abutments. The objective was to evaluate the effect of the geometry of the abutment and cementing agents on VMD. Methods Cast copings were cemented on implant abutments customized cylindrical (4, 5.5, and 7 mm) and on hexagonal implant abutments (4 mm) cemented or uncemented molded copings were placed (n = 4, totally 64 samples) with different luting agents. The VMD of the copings were measured in the coping-abutment interface at three reference points using a stereomicroscope. The independent Student's t test was used for comparison between the two different abutment walls. The post hoc statistical analysis was performed by the Tukey test. Results There was a significant VMD increase between noncemented and cemented cast copings using different luting agents. Abutment geometry and luting agents significantly influenced the VMD (p ≤ 0.05). Cylindrical abutment at 7 mm in height cemented with different luting agent tested showed significantly higher VMD values than cylindrical abutments of 4 mm (p=0.019). Hexagonal abutments with a 4 mm height showed significantly higher VMD values than cylindrical 4 mm abutments using zinc oxide noneugenol and glass ionomer cements (p=0.032). Conclusions Abutment geometry and luting agents influence the VMD of cast copings cemented on implant abutment. The higher the cylindrical abutment, the greater the VMD, and hexagonal wall abutments promote greater marginal gap.
Highlights
Implant-supported restorations have shown remarkable progress in recent years and have demonstrated high survival rates of up to 95% with well-documented functional and esthetic results [1, 2]
Results e mean vertical marginal discrepancies (VMD), standard deviation, minimum, and maximum values for each cast coping cemented or noncemented on different abutment geometries are presented in Table 1. e results showed a significant increase in VMD between noncemented cast copings compared with other cast copings cemented on cylindrical abutments of 4 mm, 5.5 mm, 7 mm, and hexagonal 4 mm abutments using the different tested luting agents (p < 0.05)
Abutment geometry and luting agent statistically influenced the VMD of the evaluated cast copings. e results of the present study showed that VMD values significantly increased when the cylindrical abutment was higher (4 mm vs. 7 mm) using the different luting agents tested
Summary
Implant-supported restorations have shown remarkable progress in recent years and have demonstrated high survival rates of up to 95% with well-documented functional and esthetic results [1, 2]. Implant-supported restorations can be cement-retained or screw-retained. Both methods have potential uses, the ideal option has yet to be established, and the selection depends on retrievability and esthetic factors [3]. International Journal of Dentistry according to recent studies [6], the most frequent complications are technical and biological, being significantly higher in cement-retained restorations because of disadvantages related to vertical marginal discrepancies (VMD) and excess cement extrusion on the peri-implant tissues. In most cases, residual excess cement may promote bleeding, local inflammation, and suppuration [7, 8]
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