12 Operative Dentistry: Matrix and Wedging
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Questions and Answers

What should be the direction of the open side of the Tofflemire retainer when placed around the tooth?

  • Facing occlusally
  • Facing mesially
  • Facing labially
  • Facing gingivally (correct)

    • When removing the bands from interproximal contacts, what is critical to preserve?

  • The size of the restoration
  • The integrity of the gingival margin
  • The shape of the marginal ridge (correct)
  • The position of the retainer

    • What is the purpose of tightening or loosening the rod on the Tofflemire retainer?

  • To control the matrix circumference (correct)
  • To change the band material
  • To secure the restoration in place
  • To adjust the angulation of the head

    • What measurement should the occlusal portion of the Tofflemire band extend above the marginal ridge?

    <p>1.5 - 2.0 mm</p> Signup and view all the answers

    Which indication is suitable for using the Tofflemire matrix?

    <p>Class I compound with buccal or lingual extensions</p> Signup and view all the answers

    What is a feature of the UltraDent Omni Matrix?

    <p>Allows easy adjustment of circumference</p> Signup and view all the answers

    What type of Tofflemire retainer should be used when there is a missing buccal wall?

    <p>Contra angled retainer</p> Signup and view all the answers

    How does the ultradent Omni-Matrix band release after restoration?

    <p>It is designed to release without disturbing the restoration</p> Signup and view all the answers

    What is the primary function of a dental matrix?

    <p>To define the proper contour and support the restoration</p> Signup and view all the answers

    Which of the following is NOT a requirement for an effective matrix?

    <p>High absorption of moisture</p> Signup and view all the answers

    What is one of the advantages of using a sectional matrix?

    <p>Enhances the adaptation of the restoration through pressure</p> Signup and view all the answers

    How does a wedging technique contribute to the effectiveness of a dental matrix?

    <p>It prevents marginal overhangs of the restoration</p> Signup and view all the answers

    Which type of matrix is specifically designed to adapt closely to the tooth's contours?

    <p>Sectional matrix</p> Signup and view all the answers

    What is a characteristic feature of an ideal dental matrix?

    <p>Smooth surface for biocompatibility</p> Signup and view all the answers

    What does the term 'circumferential matrix' refer to?

    <p>A matrix that surrounds the entire preparation</p> Signup and view all the answers

    What is the primary drawback of not using a matrix during restoration placement?

    <p>Inability to restore missing dental surfaces</p> Signup and view all the answers

    What is the primary purpose of using a thicker matrix band in dental restorations?

    <p>To prevent deformation during condensation</p> Signup and view all the answers

    Which of the following is NOT a classification based on the perimeter of matrix bands?

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

    In the Tofflemire matrix system, what is the most commonly used band shape?

    <p>No. 1 band</p> Signup and view all the answers

    What is a primary characteristic of flat matrix bands when compared to pre-contoured bands?

    <p>Flat bands can be contoured before or after placement</p> Signup and view all the answers

    Which thickness of flat bands is typically chosen to aid in achieving tight contact during restorations?

    <p>0.0010 inches</p> Signup and view all the answers

    What is the purpose of contouring a flat band before placement?

    <p>To create a better fit for the restoration</p> Signup and view all the answers

    Which type of matrix band is typically used for teeth with deep gingival margins in the proximal aspects?

    <p>No. 2 band</p> Signup and view all the answers

    What material factor is NOT considered when classifying matrix systems?

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

    What is the primary function of wedges during dental procedures?

    <p>To promote more conservative preparation and protect adjacent teeth</p> Signup and view all the answers

    Which type of wedge is recommended for deeper and wider proximal preparations?

    <p>Wooden Anatomical Wedge</p> Signup and view all the answers

    What characteristic distinguishes light reflecting plastic wedges from regular plastic wedges?

    <p>They have built-in light reflecting properties</p> Signup and view all the answers

    In which class of restorations is the cervical clear matrix primarily used?

    <p>Class V</p> Signup and view all the answers

    Where should a wedge be positioned during placement?

    <p>Gingival to the gingival margin</p> Signup and view all the answers

    Which matrix shape is best suited for single, freestanding teeth?

    <p>O-shape</p> Signup and view all the answers

    What advantage do wooden wedges exhibit when used during dental procedures?

    <p>They swell when wet to improve separation</p> Signup and view all the answers

    What type of matrix is indicated for Class III and IV restorations?

    <p>Anterior Matrix</p> Signup and view all the answers

    What is the consequence of placing a wedge more occlusal to the gingival margin?

    <p>It creates abnormal concavity in the proximal surface of the restoration.</p> Signup and view all the answers

    What should be avoided when placing wedges in relation to inflamed gingiva?

    <p>Placing the wedge directly against the inflamed area.</p> Signup and view all the answers

    What happens if a wedge is placed more apical to the gingival margin?

    <p>Gingival overhangs in the restorations will occur.</p> Signup and view all the answers

    What is the primary goal when tightening the matrix band against the tooth?

    <p>To avoid any overhang of the restoration.</p> Signup and view all the answers

    What characteristic of the cavity indicates a risk of needing a wedge?

    <p>Presence of large cavity flutes near the gingival area.</p> Signup and view all the answers

    What is the main design characteristic of the Automatrix system?

    <p>It is a retainerless matrix system.</p> Signup and view all the answers

    Which component is NOT part of the Automatrix system?

    <p>Bitine ring</p> Signup and view all the answers

    What is a significant advantage of the Automatrix system?

    <p>It offers improved visibility due to the absence of a retainer.</p> Signup and view all the answers

    What is a disadvantage of the Automatrix system?

    <p>It is difficult to develop proper proximal contours and contacts.</p> Signup and view all the answers

    What is one of the primary benefits of sectional matrices?

    <p>They create tighter anatomical contacts effectively.</p> Signup and view all the answers

    How do sectional matrices typically improve the process of composite insertion?

    <p>By stabilizing the matrix band and providing tooth separation.</p> Signup and view all the answers

    What type of matrix system is described as being dentist friendly?

    <p>Sectional matrices</p> Signup and view all the answers

    What is a unique feature of the sectional matrix regarding its design?

    <p>It is very thin and comes in various sizes.</p> Signup and view all the answers

    Study Notes

    Introduction to Matrix and Wedging

    • Batterjee Medical College presentation on matricing and wedging for operative dentistry
    • Presented by Dr. Doaa Alhelais, Consultant Advanced Restorative Dentistry, Operative Dentistry Division
    • Lots of Questions/Review material

    References

    • Art and science of operative dentistry 6th edition
    • An evidence-based review of dental matrix systems
    • Authors: Barry M. Owens, DDS & Jeffrey G. Phebus, DDS

    Learning Objectives (ILOs)

    • Define matrix and its function
    • Identify different types of matrices and their advantages
    • Learn application and removal techniques for each matrix type
    • Identify different types of wedges and their application techniques

    Outline

    • Matrix (definition, function, requirement)
    • Matrix classification
    • Circumferential matrices with application techniques for each type
    • Sectional matrices
    • Wedging

    Matrix

    • Contour highest point B, 2
    • Contacts proximal surfaces
    • Key anatomical details like incisal, occlusal, and gingival embrasures
    • Matrix is described as a properly contoured piece of metal or other material used to support and give form to the restoration
    • Used to maintain the shape of the tooth during restoration placement and hardening
    • Crucial for controlling restoration placement and contour

    Function of Matrix

    • Establishes proper contour and contact
    • Prevents marginal overhangs
    • Increases density and adaptation of the restoration via pressure application
    • Provides a smooth surface for improved biocompatibility with surrounding tissues
    • In many cases, a matrix wall prevents placement and contouring of the restoration without assistance
    • Matrix placement/contour is needed for proper restoration

    Requirements of an Ideal Matrix

    • Easy to adapt to teeth
    • Easy to contour and remove
    • Sufficient rigidity
    • Thin enough to not interfere with tooth contact
    • Smooth and highly polished surface
    • Compatible with restorative materials

    Matrix Classification

    • Based on material (Metal, Plastic)
    • Based on thickness (Thick, thin, ultra-thin)
    • Based on rigidity (Rigid, flexible)
    • Based on circumference (circumferential, sectional)

    Types of Matrices

    • Tofflemire (Universal): Commonly used in the U.S.; consists of bands and retainers
      • Bands: Flat bands in different thicknesses (0.0010, 0.0015, 0.0020 inches).
        • Thicker bands offer better resistance to deformation.
        • Thinner ones aid in achieving a tighter contact in Class 2 restorations.
        • Suitable contouring before or after use based on design
      • Retainer: Features a head (slot) that should face gingivally to aid in placement around the tooth.
        • Types: Straight, contra-angled
    • Automatrix: Retainerless matrix system for all types of teeth; simpler procedure for adapting to the tooth shape
    • Walser: Comes in various shapes (X,O,ON,XF) to accommodate various teeth types and restoration procedures
    • Sectional matrices: Relatively easy to use, very thin, and come in different sizes for adjustments during a procedure

    Indications for Matrix Use

    • Class I composite restorations with buccal or lingual extensions
    • Class II composite cavities on one or both proximal surfaces of posterior teeth
    • Additional tooth separation during composite insertion

    Wedging

    • Used for pre-wedging, promoting conservative preparation and protecting adjacent teeth
    • Prevents marginal overhangs and provides separation
    • Maintains adequate temporary tooth separation
    • Ensures close adaptability of the matrix band
    • Establishes proper retraction of the rubber dam and gingiva

    Types of Wedges

    • Wooden wedges: Available in various sizes, either straight or anatomically shaped. absorb water to improve separation during the procedure
    • Plastic wedges: Transparent or light-reflecting plastic, useful in light curing procedures. aid in visibility of the area during composite curing.

    Wedge Placement

    • Insert wedges from the side with the widest embrasure.
    • Wedge base must be positioned gingival to gingival margin.
    • Sufficient tightness to prevent overhangs.
    • Check for proper matrix tightness against the gum margin.
    • Considerations when rubber dam is not available.

    Assembly and Placement

    • Band position: Occlusal portion extends 1.5-2.0 mm above marginal ridge ; gingival portion extends 0.5 mm below gingival margin.
    • Ensuring there is no extra space between the band and the tooth

    Additional Considerations

    • Avoiding placement in inflamed gingival tissues

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    Matricing and Wedging PDF

    Description

    Explore the fundamentals of matrix and wedging in operative dentistry through this informative quiz. Presented by Dr. Doaa Alhelais, you'll learn about different types of matrices, their advantages, and application techniques. Dive into essential concepts that enhance your understanding of dental practices and improve patient outcomes.

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