Craigs Restorative Dental Materials - chapter 1&2
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Questions and Answers

What is the primary characteristic of dentin that indicates its behavior under stress?

  • Brittle fracture
  • Elasticity
  • Viscoelasticity (correct)
  • Ductility

    • How does the scalloped structure affect stress concentrations at DEJ interface?

  • It doubles the stress concentrations.
  • It has no effect on stress concentrations.
  • It reduces stress concentrations. (correct)
  • It increases stress concentrations.

    • What is strain rate sensitivity primarily associated with?

  • Ceramic materials
  • Polymeric materials (correct)
  • Metallic materials
  • High temperature stability

    • Which of the following sizes is true for larger scallops in molars?

    <p>~24 μm across</p> Signup and view all the answers

    What happens to the elastic recovery of dentin after stress is removed?

    <p>It is time dependent.</p> Signup and view all the answers

    What can be inferred about the anatomical DEJ based on the proximity of dentin crystals to enamel crystals?

    <p>It is optically thin.</p> Signup and view all the answers

    Which statement is true regarding the role of collagen in dentin?

    <p>It contributes to strain rate sensitivity.</p> Signup and view all the answers

    In terms of hardness, how does dentin compare to larger GPa values?

    <p>Dentin hardness ranges between 0.13 - 0.51 GPa.</p> Signup and view all the answers

    What unique role does the dental enamel-dentin junction (DEJ) play?

    <p>It resists cracks in enamel from penetrating into dentin.</p> Signup and view all the answers

    Which material has a higher density?

    <p>Enamel</p> Signup and view all the answers

    What is the compressive modulus of elasticity for dentin?

    <p>18-24 GPa</p> Signup and view all the answers

    How does the DEJ impact the occurrence of tooth fractures?

    <p>It is usually intact unless there is severe trauma.</p> Signup and view all the answers

    Which type of strength is higher in dentin compared to enamel?

    <p>Shear strength</p> Signup and view all the answers

    What characteristic is seen in the DEJ concerning its shape?

    <p>It is scaloped with its concavity directed toward the enamel.</p> Signup and view all the answers

    What is the proportional limit strength of enamel?

    <p>70-353 MPa</p> Signup and view all the answers

    What happens to cracks in enamel when they reach the DEJ?

    <p>They stop at or just past the interface.</p> Signup and view all the answers

    What factors heavily influence the adaptation of implants to bone and soft tissue?

    <p>Surface texture, coatings, and implant geometry</p> Signup and view all the answers

    Why is there an increasing focus on the toxicity of dental materials?

    <p>Federal agencies are becoming more concerned about health impacts.</p> Signup and view all the answers

    What will challenge restorations in patients with reduced salivary flow?

    <p>Management of multiple chronic diseases and medications</p> Signup and view all the answers

    What is a significant impact of aging on dental restoration requirements?

    <p>A rise in restorations for exposed root surfaces and worn dentitions</p> Signup and view all the answers

    Which organization is involved in establishing standard practices for biological interaction of materials?

    <p>American Dental Association (ADA)</p> Signup and view all the answers

    What interaction is rapidly growing in importance in dental materials science?

    <p>The connection between biomaterials and molecular biology</p> Signup and view all the answers

    What characteristic is essential for new dental materials to mimic natural dentition?

    <p>Depth of color and optical characteristics</p> Signup and view all the answers

    What particular challenge will restorative materials face in the context of changing salivary conditions?

    <p>Adhesion to surfaces becoming more difficult</p> Signup and view all the answers

    Which type of studies examine biofilms that form on restorative materials?

    <p>In vivo, in situ, and in vitro studies</p> Signup and view all the answers

    What is a significant factor influencing bacterial adhesion to dental materials?

    <p>Salivary protein interactions at small distances</p> Signup and view all the answers

    Which organism is noted for having higher levels in biofilms near posterior resin restorations?

    <p>Streptococcus mutans</p> Signup and view all the answers

    What has research shown about the consistency of results in in vivo and in situ studies of biofilm formation?

    <p>Results have been inconsistent and vary significantly</p> Signup and view all the answers

    What does the formation of oral biofilms on materials depend on?

    <p>A complex interaction of various factors</p> Signup and view all the answers

    Which property is NOT typically associated with the adhesion of bacteria to dental materials?

    <p>The size of salivary proteins</p> Signup and view all the answers

    What factor significantly affects the prognosis of long-span fixed dental prostheses?

    <p>Stiffness and elasticity of the materials</p> Signup and view all the answers

    What is a significant benefit of dental implants over fixed multi-unit restorations?

    <p>No preparation of adjacent teeth required</p> Signup and view all the answers

    Which characteristic of ceramic is essential when selecting a material for an all-ceramic crown?

    <p>Machining characteristics</p> Signup and view all the answers

    Why is hardness considered an important property of restorative dental materials?

    <p>It influences the material's ability to be polished</p> Signup and view all the answers

    What trend is influencing the development of restorative dental materials?

    <p>Consumer preference for natural looking appearances</p> Signup and view all the answers

    In high-caries-risk patients, what benefit can materials that release fluoride provide?

    <p>Potential prevention of caries</p> Signup and view all the answers

    What is an important consideration when designing dental prostheses that are integrated with bone?

    <p>The properties of materials and mechanics</p> Signup and view all the answers

    What will continue to be used for patients with less adequate access to dental care?

    <p>Removable prostheses</p> Signup and view all the answers

    What percentage of the tooth structure is comprised of organic components and water combined?

    <p>15%</p> Signup and view all the answers

    What is the approximate size of the long crystals that form the mineral in tooth structure?

    <p>40 nm</p> Signup and view all the answers

    What complicates the determination of the extent of crystal spans in enamel?

    <p>Fracture during preparation procedures</p> Signup and view all the answers

    Which of the following statements is likely true regarding the growth of enamel crystals?

    <p>They may span the whole enamel thickness.</p> Signup and view all the answers

    Which characteristic is notable about the crystals in tooth mineral structures?

    <p>They are hexagonal and very long.</p> Signup and view all the answers

    What percentage of water is found in the composition of tooth structure?

    <p>12%</p> Signup and view all the answers

    What is the primary objective of utilizing a systems approach in restorative dentistry?

    <p>To integrate various scientific disciplines for optimal patient outcomes.</p> Signup and view all the answers

    Which of the following restorative dental materials typically exhibits high flexibility?

    <p>Impression materials</p> Signup and view all the answers

    What is the significance of integrating clinician experience with scientific evidence in restorative dentistry?

    <p>It allows for a more personalized and effective patient care strategy.</p> Signup and view all the answers

    Which broad class of materials is NOT typically included in restorative dentistry?

    <p>Biomaterials</p> Signup and view all the answers

    What role does the understanding of biomechanical principles play in restorative dentistry?

    <p>It serves as a foundation for selecting materials suited to dental applications.</p> Signup and view all the answers

    What is an essential factor that affects the performance of restorative materials in clinical applications?

    <p>The material's response under stress and environmental conditions.</p> Signup and view all the answers

    Which characteristic is desired in dental materials to ensure their effectiveness over time?

    <p>Resistance to wear and degradation under oral conditions.</p> Signup and view all the answers

    Which type of dental material is considered least relevant for restoration procedures?

    <p>Gypsum materials</p> Signup and view all the answers

    What is primarily influenced by the structural variations of the enamel near the dentin-enamel junction (DEJ)?

    <p>The development of enamel prisms</p> Signup and view all the answers

    How does the mineral composition of enamel and dentin primarily differ?

    <p>Dentin is influenced by its formative history unlike enamel</p> Signup and view all the answers

    What role do metal ions, such as magnesium and sodium, play in the structure of enamel and dentin?

    <p>They replace calcium in the mineral matrix</p> Signup and view all the answers

    What happens to the atomic structure of enamel as a result of ionic substitutions?

    <p>It distorts and becomes more soluble</p> Signup and view all the answers

    What is a key feature of the initial enamel structure at the DEJ compared to the rest of the enamel?

    <p>It exhibits less well-defined prisms</p> Signup and view all the answers

    What implications does the variable composition of dentin have for dental health?

    <p>It increases tooth sensitivity</p> Signup and view all the answers

    What happens to the mechanical properties of enamel as a result of its carbonate-rich composition?

    <p>It reduces tensile strength</p> Signup and view all the answers

    What is one consequence of the structural differences between enamel and dentin regarding their interaction?

    <p>Enamel may fracture more easily at the DEJ</p> Signup and view all the answers

    What is the primary composition of peritubular dentin?

    <p>A cuff of minerals with higher carbonate content</p> Signup and view all the answers

    What is the estimated size of the dentin tubules as mentioned?

    <p>Approximately 5 × 30 × 100 nm</p> Signup and view all the answers

    What effect does cutting dentin have in regards to smear layer formation?

    <p>It creates a protective coating obscuring the underlying structure</p> Signup and view all the answers

    Why might the smaller crystallite size of dentin crystals impact their behavior?

    <p>It increases susceptibility to dissolution</p> Signup and view all the answers

    What role does intertubular dentin play in dental structure?

    <p>It separates the tubules and supports peritubular dentin</p> Signup and view all the answers

    What consequence arises from the development of smear plugs during dentin cutting?

    <p>They may hinder the flow of dentin fluid and increase sensitivity</p> Signup and view all the answers

    How does the carbonate content in dentin crystals affect its overall properties?

    <p>Higher carbonate content reduces the hardness of dentin</p> Signup and view all the answers

    What happens to the dental structure at the occlusal surface when dentin is abraded?

    <p>A smear layer forms that covers and obscures underlying structures</p> Signup and view all the answers

    What is a primary reason for the faster progression of caries once they reach dentin compared to enamel?

    <p>Dentin tubules provide pathways for dissolution.</p> Signup and view all the answers

    How does the unique structure of enamel contribute to its function in the oral environment?

    <p>It provides high hardness and wear resistance.</p> Signup and view all the answers

    What is the significance of the organic substances found in enamel's microstructure?

    <p>They increase toughness compared to pure apatite.</p> Signup and view all the answers

    What outcome does the structure of dentin tubules produce along with their varying moisture levels?

    <p>Variation in the number of tubules per unit area.</p> Signup and view all the answers

    What is one major consequence of the high mineral content in enamel when facing acid exposure?

    <p>Enamel is etched differently compared to dentin.</p> Signup and view all the answers

    Why might early enamel caries be treated differently from dentin caries?

    <p>Enamel caries can be remineralized more effectively.</p> Signup and view all the answers

    What role do odontoblasts play in relation to dentin tubules?

    <p>They traverse the tubules from the pulp chamber to the DEJ.</p> Signup and view all the answers

    How does the packing of enamel crystals affect its surface characteristics when subjected to acids?

    <p>It enhances the roughness of enamel.</p> Signup and view all the answers

    Study Notes

    Role and Significance of Restorative Dental Materials

    • A comprehensive understanding of materials and mechanics is crucial for predicting the prognosis of dental restorations.
    • Long-span fixed dental prostheses' effectiveness relies on the stiffness and elasticity of the materials used.
    • Esthetic considerations dictate that hardness influences a material's polishability, impacting patient satisfaction.
    • Fluoride-releasing materials offer benefits for high-caries-risk patients when exposed to water.
    • An emerging trend favors natural-looking dental restorations, shifting away from the uniform white appearance previously desired.

    Dental Implants

    • Dental implants integrate with bone and require specific surface textures, coatings, and geometries for optimal adaptation with soft tissues.
    • Research is ongoing into improved materials and designs to better mimic natural dentition.

    Tooth Structure Properties

    • Comparison of enamel and dentin shows distinct differences in physical properties, such as density and compressive strength.
    • Enamel exhibits superior hardness and strength, but the dentin’s viscoelastic nature contributes to its deformation characteristics.
    • The dentin-enamel junction (DEJ) plays a critical role in preventing crack propagation between these two materials.

    Biofilms and Restorative Materials

    • Biofilm accumulation on restorative dental materials complicates the challenge of managing oral hygiene.
    • Inconsistent results from studies on bacterial adhesion and biofilm formation highlight the complexity of these processes and their dependency on various factors.
    • In vitro research indicates that cariogenic bacteria may proliferate more around certain restorative materials, influencing caries development.

    Challenges in Older Populations

    • Increasing use of restorative materials requires consideration of unique challenges faced by aging individuals, including dry mouth and altered salivary pH.
    • Biointeraction between materials and tissues is being standardized to better address the needs of populations with chronic health issues.

    Importance of Materials Science in Dentistry

    • Knowledge in materials science and biomechanics is crucial for selecting appropriate materials in dental applications.
    • A systems approach assesses chemical, physical, and engineering aspects of dental materials.
    • Consideration of physiological, pathological, and biological factors enhances restorative procedures and patient outcomes.

    Restorative Dental Materials

    • Types of materials used include metals, polymers, ceramics, and composites.
    • Specific restorative materials encompass resin composites, dental cements, glass ionomers, ceramics, noble metals, base metals, amalgam alloys, and impression materials.
    • Material characteristics range from high flexibility in impression materials to high stiffness required for restorations.

    Enamel and Dentin Structure

    • Tooth structure comprises enamel, which is the hardest tissue in the body, and dentin, which has a more variable composition influenced by formative history.
    • Enamel contains long hexagonal crystals approximately 40 nm across, contributing to its structural integrity.
    • Dentin has a calcium-deficient, carbonate-rich mineral composition with smaller apatite crystals compared to enamel, leading to different susceptibilities to dissolution.

    Bonding and Composition

    • Dental bonding requires infiltrating agents that polymerize after penetrating the etched surface of dental structures.
    • The organic components represent about 3% of tooth structure, while water accounts for 12%.
    • Modifications to mineral structure, such as substitutions of magnesium and carbonate, affect solubility and strength.

    Dentin Tubules and Structural Variations

    • Dentin features tubular structures that allow for pathways during formation, influencing properties like moisture content and density of tubules across different areas.
    • The peritubular and intertubular dentin present unique characteristics impacting dental treatments and restoration.

    Clinical Implications of Tooth Structure

    • Enamel’s high mineral content provides durability and resistance to wear, critical for masticatory functions.
    • Dentin's structure allows for quicker progression of caries once enamel is breached, necessitating different treatment approaches.
    • The smear layer forms on dentin surfaces during cutting, obscuring underlying tubules, which must be understood when planning restoration treatments.

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    Craig's Restorative Dental Materials PDF

    Description

    Test your knowledge on the role and significance of restorative dental materials, particularly in crowns and fixed dental prostheses. This quiz covers fundamental principles of materials and their integration with dental implants. Enhance your understanding of this crucial aspect of restorative dentistry.

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