Short answer
When designing or manufacturing dental restorations, prioritize finish line designs that offer a balance of precise fit and structural integrity, acknowledging that the theoretically 'best' fit might not be clinically viable.
- Field
- Final Production
- Source
- Operative Dentistry (2009)
- Method
- Comparative experimental study
- Sample
- 28 participants (7 per finish line design group)
- Evidence
- Strong effect
The design of the cervical finish line significantly impacts the precision of fit for zirconia ceramic crowns, with feather-edge designs demonstrating the tightest marginal gaps. This final production research insight is drawn from a 2009 study published in Operative Dentistry. Using Comparative experimental study with 28 participants (7 per finish line design group), researchers explored how this design variable affects real-world outcomes. The key design takeaway: When designing or manufacturing dental restorations, prioritize finish line designs that offer a balance of precise fit and structural integrity, acknowledging that the theoretically 'best' fit might not be clinically viable.
Feather-edge finish lines yield superior marginal adaptation in zirconia crowns, but with mechanical caveats.
The design of the cervical finish line significantly impacts the precision of fit for zirconia ceramic crowns, with feather-edge designs demonstrating the tightest marginal gaps.
Operative Dentistry · 2009
Key Findings
- 01The feather-edge finish line resulted in significantly lower Absolute Marginal Opening (AMO) and Marginal Opening (MO) values compared to chamfer, shoulder, and mini-chamfer designs.
- 02Despite superior marginal adaptation, the feather-edge design is not clinically recommended due to its inherent mechanical disadvantages.
Application
Design takeaway
When designing or manufacturing dental restorations, prioritize finish line designs that offer a balance of precise fit and structural integrity, acknowledging that the theoretically 'best' fit might not be clinically viable.
How to apply
When specifying or evaluating dental crown preparations, consider the finish line geometry as a critical factor influencing the final fit and longevity of the restoration. Explore manufacturing techniques that can precisely replicate these geometries.
Project actions
- 01When designing a product that requires precise fitting components, consider how the interface geometry affects the final assembly and performance.
- 02Investigate different manufacturing tolerances and their impact on the functional outcome of your design.
Method & Evidence
Variables
Strengths & Limitations
Strengths
- +Clear comparison between multiple distinct finish line designs.
- +Quantitative measurement of marginal gaps using standardized methods.
Limitations
The study focused on a specific material (zirconia) and cement type, so results may vary with different materials or bonding agents. The 'mechanical disadvantage' of the feather-edge was stated but not experimentally verified within this paper.
Reliability & validity
The study employed a stereomicroscope with image processing software for measurements, enhancing the reliability of gap assessment. The use of statistical tests (Kruskal Wallis, Mann Whitney, Wilcoxon Signed Ranks) at a strict significance level (alpha = 0.01) supports the validity of the findings regarding differences between groups.
Think critically
Given the mechanical limitations of the feather-edge design, what alternative strategies could be employed in manufacturing or material selection to achieve superior marginal adaptation without compromising structural integrity?
Design Principles
"Optimize geometric interfaces for functional performance and material limitations."
Achieving a precise fit between a dental crown and the prepared tooth is crucial for long-term restoration success, preventing issues like leakage and secondary decay. Understanding how different finish line designs influence this fit allows for more informed material and manufacturing choices in restorative dentistry.
What This Means for Your Design
The shape of the edge where the crown meets the tooth affects how well the crown fits. A 'feather-edge' shape made the crown fit very tightly, but it's not strong enough for real-life use. Other shapes, like 'shoulder' or 'mini-chamfer', fit almost as well and are stronger.
How to use in your project
- 1.Reference this study when discussing the importance of precise manufacturing and geometric design in achieving functional product performance, particularly in areas requiring tight tolerances.
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Quick Cite
Paragraph starter
The study by Çömlekoğlu et al. (2009) demonstrated that the cervical finish line type significantly influences the marginal adaptation of zirconia ceramic crowns. While the feather-edge design yielded the tightest marginal gaps, its clinical viability was questioned due to mechanical disadvantages, suggesting that designs like the shoulder or mini-chamfer offer a more practical balance of fit and robustness for restorative applications.
Source
Operative Dentistry
Influence of Cervical Finish Line Type on the Marginal Adaptation of Zirconia Ceramic Crowns
journal · 2009
View sourceQuestions About This Research
- What does the research say about feather-edge finish lines yield superior marginal adaptation in zirconia crowns, but with mechanical caveats?
- When designing or manufacturing dental restorations, prioritize finish line designs that offer a balance of precise fit and structural integrity, acknowledging that the theoretically 'best' fit might not be clinically viable. Evidence: Operative Dentistry (2009).
- Why does "Feather-edge finish lines yield superior marginal adaptation in zirconia crowns, but with mechanical caveats." matter for design?
- Achieving a precise fit between a dental crown and the prepared tooth is crucial for long-term restoration success, preventing issues like leakage and secondary decay. Understanding how different finish line designs influence this fit allows for more informed material and manufacturing choices in restorative dentistry.
- How can designers apply this research?
- When designing or manufacturing dental restorations, prioritize finish line designs that offer a balance of precise fit and structural integrity, acknowledging that the theoretically 'best' fit might not be clinically viable.
- What were the main findings?
- The feather-edge finish line resulted in significantly lower Absolute Marginal Opening (AMO) and Marginal Opening (MO) values compared to chamfer, shoulder, and mini-chamfer designs.. Despite superior marginal adaptation, the feather-edge design is not clinically recommended due to its inherent mechanical disadvantages.
- What research method was used?
- Comparative experimental study with 28 participants (7 per finish line design group).
- How strong is the evidence?
- Evidence strength is rated Strong effect, based on a 2009 journal from Operative Dentistry.
- What should I do differently in my next project?
- When specifying or evaluating dental crown preparations, consider the finish line geometry as a critical factor influencing the final fit and longevity of the restoration. Explore manufacturing techniques that can precisely replicate these geometries.
- What are the limitations?
- The study used epoxy resin die models, which may not perfectly replicate the mechanical properties of natural teeth. The mechanical disadvantages of the feather-edge design were noted but not quantified in this study.