Basic Operative Dentistry Tooth Preparations

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Questions and Answers

What happens when enamel starts to decalcify?

It starts to look chalky.

Axial Wall is ___ to the Long Axis of the Tooth.

parallel

Pulpal Floor or Wall is __ to the Long Axis of the Tooth.

perpendicular

What are line angles?

<p>Where two surfaces come together.</p> Signup and view all the answers

What is a point angle?

<p>Where three surfaces come together.</p> Signup and view all the answers

How are surfaces classified in dental caries?

<p>Compound (A), Simple (B), Complex (C)</p> Signup and view all the answers

What classification does GV Black use for dental caries?

<p>Class III: Proximal surfaces of anterior teeth (A), Class I: All pits and fissures (B), Class II: Proximal surfaces of posterior teeth (C), Class IV: Proximal surfaces of anterior teeth with incisal angle involved (D)</p> Signup and view all the answers

Classes II-VI are smooth surface caries.

<p>True (A)</p> Signup and view all the answers

What is interproximal?

<p>In between the teeth.</p> Signup and view all the answers

The pulpal wall is __ to the long axis of the tooth.

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

The axial wall is __ to the long axis of the tooth.

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

What must be done during a Class II preparation?

<p>Prewedge and place a matrix on the adjoining tooth.</p> Signup and view all the answers

What is the function of a matrix retainer?

<p>To restore amalgam restorations (A)</p> Signup and view all the answers

What are the steps for Class II amalgam preparations?

<p>Outline form, primary resistance form, primary retention form, convenience form, removal of decay, pulp protection if indicated, margination, debridement.</p> Signup and view all the answers

What is the outline form?

<p>The outer shape of the preparation.</p> Signup and view all the answers

Facial and lingual walls being parallel or slightly acute is __.

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

What is the importance of breaking contact during cavity preparation?

<p>To remove unsupported enamel and access decay.</p> Signup and view all the answers

Which of the following tooth preparation methods does NYU currently teach?

<p>Modified Classic Preparations (B), Contemporary Preparations (C)</p> Signup and view all the answers

What is caries?

<p>An infectious disease that can lead to the formation of cavities.</p> Signup and view all the answers

The objectives of tooth preparation include removing defects and protecting the ___.

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

What are the nine steps in cavity preparation?

<ol> <li>Outline Form &amp; Initial Depth, 2. Primary Resistance Form, 3. Primary Retention Form, 4. Convenience Form, 5. Removal of Decay, 6. Pulp Protection if indicated, 7. Secondary Resistance &amp; Retention Forms, 8. Cavosurface Finish, 9. Debridement of the Preparation.</li> </ol> Signup and view all the answers

How many steps did cavity preparation used to have?

<p>7 steps</p> Signup and view all the answers

Which classes of tooth caries are classified under GV Black?

<p>All of the above (D)</p> Signup and view all the answers

What is the definition of Class I caries?

<p>All pit and fissure caries.</p> Signup and view all the answers

What is the primary resistance form in tooth preparation?

<p>The internal shape that prevents fracture of the filling material and/or the tooth.</p> Signup and view all the answers

What are the rules for the outline form of a Class I prep?

<p>Width: 1.0 mm, Depth: 1.7 - 2 mm.</p> Signup and view all the answers

What is the function of an amalgam condenser?

<p>To measure the facial lingual width of the Class I prep.</p> Signup and view all the answers

What is the proper cavosurface finish in tooth preparation for amalgam restorations?

<p>A butt joint with a 90 degree exit angle.</p> Signup and view all the answers

What is debridement of the preparation?

<p>Flushing out all debris from the cavity preparation.</p> Signup and view all the answers

What instruments are needed for starting preparations?

<p>Mirror, Explorer (#23), Perioprobe, College pliers (tweezers).</p> Signup and view all the answers

What happens when enamel starts to decalcify?

<p>Enamel rods start to flake out, leading to potential cavities.</p> Signup and view all the answers

Flashcards

Modified Classic Preparations

A technique in operative dentistry focusing on less invasive tooth preparation methods, emphasizing the preservation of healthy tooth structure. It aims to minimize alteration to the tooth, creating smaller preparations than the traditional approach.

Contemporary Preparations

A modern approach to tooth preparation that prioritizes minimal intervention, creating holes to be filled while maintaining the integrity of the tooth structure as much as possible.

Caries

An infectious disease that can lead to cavities. It involves the breakdown of tooth enamel and dentin due to the presence of bacteria.

Tooth Preparation

The process of preparing a tooth for a restoration by removing decay and shaping the tooth structure. It involves using instruments to create the appropriate shape and depth required for the filling or crown.

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Outline Form & Initial Depth

The initial step in cavity preparation where the outline and depth of the preparation are established. This ensures proper access to the affected area while preserving as much tooth structure as possible.

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Resistance Form

The internal design of a cavity preparation that is designed to withstand mastication forces. It ensures the preparation does not fracture or collapse under the pressure of chewing.

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Retention Form

The shaping of the cavity walls to ensure the restoration remains in place. It involves creating angles that prevent the filling or crown from falling out.

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Convenience Form

Adjustments made to the cavity preparation to provide better access to the decay that extends beyond the ideal preparation margins. This helps ensure that all the decay is removed while minimizing damage to the tooth.

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Removal of Decay

The process of removing the infected tissue in a cavity using instruments like rotary burs. It involves carefully excavating the decay while minimizing the chance of damaging the healthy tooth structure.

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Pulp Protection

Procedures used to protect the pulp (soft tissue inside the tooth) when the cavity preparation approaches it. This may involve placing a protective base or liner to prevent irritation or damage.

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Secondary Resistance & Retention Forms

Additional techniques used to ensure the retention and resistance of the restoration when primary forms are insufficient. It involves creating additional angles and shapes to enhance the stability of the restoration.

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Cavosurface Finish

The final shaping of the cavity margins to ensure a smooth transition between the restoration and the tooth structure. It helps to prevent fractures and micro-gaps that could lead to future decay.

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Debridement

The final cleaning step in a cavity preparation. This involves removing any debris or particles left behind after the preparation process, ensuring a clean surface for the restoration.

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Classes of Tooth Caries

A classification system created by G.V. Black that categorizes cavities based on their location and extent on the tooth. There are six classes of tooth caries: Class I through VI.

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Class I Caries

Caries that occur in the pits and fissures of molars and premolars, as well as the lingual surfaces of anterior teeth. These are usually in areas where tooth enamel is naturally weak and prone to decay.

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Class II Caries

Caries that affect the proximal surfaces (surfaces next to adjacent teeth) of posterior teeth (premolars and molars).

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Class III Caries

Caries that affect the proximal surfaces (neighboring surfaces) of anterior teeth (canines, incisors).

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Class IV Caries

Caries that affect the proximal surfaces of anterior teeth, including the incisal angle (the biting edge).

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Class V Caries

Caries that affect the gingival third (the gum-line area) of all teeth, both facially and lingually.

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Class VI Caries

Caries that affect the cusp tips of posterior teeth and the incisal edges of anterior teeth, without involving any proximal surfaces. This type of decay typically develops as a result of wear and tear.

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Smooth Surface Caries

A type of tooth decay that occurs on the smooth surfaces of teeth, as opposed to pits and fissures. This includes the surfaces of teeth that are not covered by enamel.

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Interproximal

The spaces between two adjacent teeth

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Pre-Wedge

A technique used in Class II preparations to create a wedge-shaped space between the tooth being prepared and the adjacent tooth. This helps prevent the restorative material from contacting the adjacent tooth during placement.

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Matrix

A device used in tooth restorations to form the shape of the proximal (between teeth) surface of the restoration. It helps ensure the perfect fit and contour of the filling material.

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Line Angle

The line formed by the intersection of two surfaces of a cavity preparation. For example, the intersection of the facial wall with the pulpal wall.

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Point Angle

The point formed by the intersection of three surfaces of a cavity preparation. For example, the intersection of the facial, lingual, and pulpal walls.

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Axial Wall

The wall of a cavity preparation that is parallel to the long axis of the tooth.

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Pulpal Wall

The wall of a cavity preparation that is perpendicular to the long axis of the tooth.

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Study Notes

Basic Operative Dentistry Tooth Preparations

  • NYU teaches Modified Classic and Contemporary Preparations only, moving away from classic G.V. Black styles.
  • G.V. Black is recognized as the father of modern dentistry; his methods are the foundation of current practices.
  • Modified Classic Preparations are smaller than traditional methods and focus on less invasive techniques.
  • Contemporary Preparations involve creating holes which are then filled, emphasizing minimal alteration to the tooth structure.

Caries and Treatment

  • Caries is classified as an infectious disease that can lead to cavities.
  • Surgical preparation is necessary to reduce microorganisms, but complete removal is impossible, as treatment involves cutting into live tissues like enamel and dentin.

Objectives of Tooth Preparation

  • Four main objectives drive tooth preparation:
    • Remove decay and protect the pulp
    • Minimize cutting to conserve healthy tooth structure
    • Create a strong preparation that withstands chewing forces
    • Allow for proper functional placement of restorations.

Nine Steps in Cavity Preparation

  • Steps include Outline Form & Initial Depth, Resistance and Retention Forms, Decay Removal, and Debridement, with Steps 6 and 7 being conditional based on the situation.

Details of Cavity Preparation Steps

  • Outline Form & Initial Depth: Outline shape and depth of preparation must establish proper access.
  • Primary Resistance Form: Internal design must withstand mastication forces; a well-prepared cavity resists fracture.
  • Primary Retention Form: Angles of the walls should ensure the restoration remains in place; facial/lingual walls should be nearly parallel or slightly acute.
  • Convenience Form: Adjustments made to access decay beyond ideal prep limits.
  • Removal of Decay: Involves using rotary instruments to excavate infected structures, removing the majority of decay but not all.
  • Pulp Protection: Necessary if preparation nears the pulp.
  • Secondary Resistance & Retention Forms: Techniques used when primary retention is insufficient.
  • Cavosurface Finish: Ensures margins are shaped properly to prevent fractures and overhangs, especially for amalgam which requires a 90-degree angle.
  • Debridement: Final cleaning step before restoration, removing any debris from the cavity.

Classes of Tooth Caries

  • Six classes of caries: Class I through VI, classified under G.V. Black.

Class I Definition

  • Class I caries occur primarily in pits and fissures of molars and premolars, as well as the lingual surfaces of anteriors.
  • Requires specific measurements for depth, width, and preservation of marginal ridges.

General Guidelines for Class I Preparation

  • Maintain 1mm facial-lingual width, 1.7-2mm pulpal depth, and 0.5mm into dentin at shallow points, ensuring smooth walls and proper angles.

Preparation Instruments

  • Four essential instruments: Mirror, Explorer (#23), Perioprobe, and College Pliers (Tweezers).
  • Use the #23 Explorer for detecting cavities and assessing pulp health.

Handling Decalcification

  • Decalcifying enamel appears chalky; probing may lead to confirmed cavities; sealing is recommended at this stage.

Tooth Preparation Walls

  • Internal walls (Axial and Pulpal) are oriented differently relative to the long axis of the tooth: axial is parallel, pulpal is perpendicular.
  • External walls communicate with the outside of the tooth and include facial, lingual, and mesial/distal walls.

Burrs Used in Preparation

  • Common burrs in practice include RA 56 for finishing, 1556 for shaping, and 330 for specific class preparations. The 1556 burr is optimal for depth and angle precision during cavity preparations.### Pulpal Floor and Axial Wall
  • Pulpal floor and wall are terms used interchangeably.
  • Axial floor and axial wall refer to the same structure.

Line and Point Angles

  • Line angle: Intersection of two surfaces, forming a line.
  • Point angle: Intersection of three surfaces, forming a point.

Classification by Number of Surfaces

  • Simple: Involves one surface (Class I).
  • Compound: Involves two surfaces (e.g., occlusal and mesial).
  • Complex: Involves three or more surfaces (e.g., MOD).

GV Black Classification of Dental Caries

  • Class I: Affects all pits and fissures.
  • Class II: Involves proximal surfaces of posterior teeth (premolars and molars).
  • Class III: Affects proximal surfaces of anterior teeth (canines, incisors).
  • Class IV: Involves proximal surfaces of anterior teeth, including the incisal angle.
  • Class V: Affects the gingival third of all teeth, both facially and lingually.
  • Class VI: Affects cusp tips of posterior teeth and incisal edges of anterior teeth, with no proximal surface involvement.

Classes II-VI: Caries Types

  • Classes II-VI are classified as smooth surface caries.
  • Class I represents pit and fissures caries.

Class II Caries Identification

  • Class II caries appear on distal surfaces of premolars and molars in X-rays.

Interproximal Definition

  • Interproximal refers to the spaces between teeth and is synonymous with proximal.

Class V Characteristics

  • Class V affects the gingival third of all teeth on both facial and lingual surfaces.

Class II Preparations

  • Pre-wedge all Class II preparations to avoid nicking the adjacent tooth.
  • A matrix (Tofflemire) is used in restorations to ensure proper fit.

Class II Amalgam Preparation Steps

  • Follow outlined steps: outline form, resistance and retention form, convenience form, removal of decay, pulp protection, margination, and debridement.

Outline Form Rules for Class II Prep

  • Maintain marginal ridge integrity, maintain 1mm facio-lingual width, and ensure tapering towards gingivo-occlusal direction.
  • Break contacts at the gingival area as this is where decay typically resides.

Light Visibility in Contact Areas

  • Light will not be seen if only gingival contact is broken; light is visible only when facial and lingual contacts are also broken.

Divergence in Proximal View

  • Diverging walls of Class II prep means facial and lingual walls taper occluso-gingivally while following tooth contours.

Resistance Form Specifications

  • Pulpal depth: 1.7-2mm; axial depth 1mm for premolars and 1.3mm for molars.
  • Ensure adequate shape to prevent any filling fracture.

Retention Form Specifications

  • Facial and lingual walls should ideally be parallel or taper slightly toward the occlusal to avoid falling out.

Unsupported Enamel in Gingival Third

  • Unsupported enamel in the gingival third can lead to decay; margination is performed to remove these areas.

Summation of Class I and Class II Box

  • Key characteristics include 1mm F-L width, smooth pulpal floor, and specific depths for proper cavity preparation.

Proximal Box Rules

  • Ensure convex axial wall, flat gingival floor, and divergent occlusal-gingival walls, maintaining parallelism between B-L walls.

Clarity on Retention and Resistance

  • Facial and lingual being parallel/slightly acute relates to retention; all other forms contribute to resistance in preparation.

Orientation to Long Axis of Tooth

  • Pulpal wall is perpendicular to the long axis of the tooth.
  • Axial wall is also perpendicular to the long axis of the tooth.

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