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Conservative Dentistry - NEETMDS- courses
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Conservative Dentistry

Inlay Preparation

Inlay preparations are a common restorative procedure in dentistry, particularly for Class II restorations.

1. Definitions

A. Inlay

  • An inlay is a restoration that is fabricated using an indirect procedure. It involves one or more tooth surfaces and may cap one or more cusps but does not cover all cusps.

2. Class II Inlay (Cast Metal) Preparation Procedure

A. Burs Used

  • Recommended Burs:
    • No. 271: For initial cavity preparation.
    • No. 169 L: For refining the cavity shape and creating the proximal box.

B. Initial Cavity Preparation

  • Similar to Class II Amalgam: The initial cavity preparation is performed similarly to that for Class II amalgam restorations, with the following differences:
    • Occlusal Entry Cut Depth: The initial occlusal entry should be approximately 1.5 mm deep.
    • Cavity Margins Divergence: All cavity margins must diverge occlusally by 2-5 degrees:
      • 2 degrees: When the vertical walls of the cavity are short.
      • 5 degrees: When the vertical walls are long.
    • Proximal Box Margins: The proximal box margins should clear the adjacent tooth by 0.2-0.5 mm, with 0.5 � 0.2 mm being ideal.

C. Preparation of Bevels and Flares

  • Primary and Secondary Flares:
    • Flares are created on the facial and lingual proximal walls, forming the walls in two planes.
    • The secondary flare widens the proximal box, which initially had a clearance of 0.5 mm from the adjacent tooth. This results in:
      • Marginal Metal in Embrasure Area: Placing the marginal metal in the embrasure area allows for better self-cleansing and easier access for cleaning and polishing without excessive dentin removal.
      • Marginal Metal Angle: A 40-degree angle, which is easily burnishable and strong.
      • Enamel Margin Angle: A 140-degree angle, which blunts the enamel margin and increases its strength.
    • Note: Secondary flares are omitted on the mesiofacial proximal walls of maxillary premolars and first molars for esthetic reasons.

D. Gingival Bevels

  • Width: Gingival bevels should be 0.5-1 mm wide and blend with the secondary flare, resulting in a marginal metal angle of 30 degrees.
  • Purpose:
    • Removal of weak enamel.
    • Creation of a burnishable 30-degree marginal metal.
    • Production of a lap sliding fit at the gingival margin.

E. Occlusal Bevels

  • Location: Present on the cavosurface margins of the cavity on the occlusal surface.
  • Width: Approximately 1/4th the depth of the respective wall, resulting in a marginal metal angle of 40 degrees.

3. Capping Cusps

A. Indications

  • Cusp Involvement: Capping cusps is indicated when more than 1/2 of a cusp is involved and is mandatory when 2/3 or more is involved.

B. Advantages

  • Weak Enamel Removal: Helps in removing weak enamel.
  • Cavity Margin Location: Moves the cavity margin away from occlusal areas subjected to heavy forces.
  • Visualization of Caries: Aids in visualizing the extent of caries, increasing convenience during preparation.

C. Cusp Reduction

  • Uniform Metal Thickness: Cusp reduction must provide for a uniform 1.5 mm metal thickness over the reduced cusps.
  • Facial Cusp Reduction: For maxillary premolars and first molars, the reduction of the facial cusp should be 0.75-1 mm for esthetic reasons.

D. Reverse Bevel (Counter Bevel)

  • Definition: A bevel given on the margins of the reduced cusp.
  • Width: Varies to extend beyond any occlusal contact with opposing teeth, resulting in a marginal metal angle of 30 degrees.

E. Retention Considerations

  • Retention Form: Cusp reduction decreases the retention form due to reduced vertical wall height. Therefore, proximal retentive grooves are usually recommended.
  • Collar and Skirt Features: These features can enhance retention and resistance form.

Nursing Bottle Caries

Nursing bottle caries, also known as early childhood caries (ECC), is a significant dental issue that affects infants and young children. Understanding the etiological agents involved in this condition is crucial for prevention and management. .

1. Pathogenic Microorganism

A. Streptococcus mutans

  • RoleStreptococcus mutans is the primary microorganism responsible for the development of nursing bottle caries. It colonizes the teeth after they erupt into the oral cavity.
  • Transmission: This bacterium is typically transmitted to the infant�s mouth from the mother, often through saliva.
  • Virulence Factors:
    • Colonization: It effectively adheres to tooth surfaces, establishing a foothold for caries development.
    • Acid ProductionS. mutans produces large amounts of acid as a byproduct of carbohydrate fermentation, leading to demineralization of tooth enamel.
    • Extracellular Polysaccharides: It synthesizes significant quantities of extracellular polysaccharides, which promote plaque formation and enhance bacterial adherence to teeth.

2. Substrate (Fermentable Carbohydrates)

A. Sources of Fermentable Carbohydrates

  • Fermentable carbohydrates are utilized by S. mutans to form dextrans, which facilitate bacterial adhesion to tooth surfaces and contribute to acid production. Common sources include:
    • Bovine Milk or Milk Formulas: Often high in lactose, which can be fermented by bacteria.
    • Human Milk: Breastfeeding on demand can expose teeth to sugars.
    • Fruit Juices and Sweet Liquids: These are often high in sugars and can contribute to caries.
    • Sweet Syrups: Such as those found in vitamin preparations.
    • Pacifiers Dipped in Sugary Solutions: This practice can introduce sugars directly to the oral cavity.
    • Chocolates and Other Sweets: These can provide a continuous source of fermentable carbohydrates.

3. Host Factors

A. Tooth Structure

  • Host for Microorganisms: The tooth itself serves as the host for S. mutans and other cariogenic bacteria.
  • Susceptibility Factors:
    • Hypomineralization or Hypoplasia: Defects in enamel development can increase susceptibility to caries.
    • Thin Enamel and Developmental Grooves: These anatomical features can create areas that are more prone to plaque accumulation and caries.

4. Time

A. Duration of Exposure

  • Sleeping with a Bottle: The longer a child sleeps with a bottle in their mouth, the higher the risk of developing caries. This is due to:
    • Decreased Salivary Flow: Saliva plays a crucial role in neutralizing acids and washing away food particles.
    • Prolonged Carbohydrate Accumulation: The swallowing reflex is diminished during sleep, allowing carbohydrates to remain in the mouth longer.

5. Other Predisposing Factors

  • Parental Overindulgence: Excessive use of sugary foods and drinks can increase caries risk.
  • Sleep Patterns: Children who sleep less may have increased exposure to cariogenic factors.
  • Malnutrition: Nutritional deficiencies can affect oral health and increase susceptibility to caries.
  • Crowded Living Conditions: These may limit access to dental care and hygiene practices.
  • Decreased Salivary Function: Conditions such as iron deficiency and exposure to lead can impair salivary function, increasing caries susceptibility.

Clinical Features of Nursing Bottle Caries

  • Intraoral Decay Pattern: The decay pattern associated with nursing bottle caries is characteristic and pathognomonic, often involving the maxillary incisors and molars.
  • Progression of Lesions: Lesions typically progress rapidly, leading to extensive decay if not addressed promptly.

Management of Nursing Bottle Caries

First Visit

  • Lesion Management: Excavation and restoration of carious lesions.
  • Abscess Drainage: If present, abscesses should be drained.
  • Radiographs: Obtain necessary imaging to assess the extent of caries.
  • Diet Chart: Provide a diet chart for parents to record the child's diet for one week.
  • Parent Counseling: Educate parents on oral hygiene and dietary practices.
  • Topical Fluoride: Administer topical fluoride to strengthen enamel.

Second Visit

  • Diet Analysis: Review the diet chart with the parents.
  • Sugar Control: Identify and isolate sugar sources in the diet and provide instructions to control sugar exposure.
  • Caries Activity Tests: Conduct tests to assess the activity of carious lesions.

Third Visit

  • Endodontic Treatment: If necessary, perform root canal treatment on affected teeth.
  • Extractions: Remove any non-restorable teeth, followed by space maintenance if needed.
  • Crowns: Place crowns on teeth that require restoration.
  • Recall Schedule: Schedule follow-up visits every three months to monitor progress and maintain oral health.

Capacity of Motion of the Mandible

The capacity of motion of the mandible is a crucial aspect of dental and orthodontic practice, as it influences occlusion, function, and treatment planning. In 1952, Dr. Harold Posselt developed a systematic approach to recording and analyzing mandibular movements, resulting in what is now known as Posselt's diagram. This guide will provide an overview of Posselt's work, the significance of mandibular motion, and the key points of reference used in clinical practice.

1. Posselt's Diagram

A. Historical Context

  • Development: In 1952, Dr. Harold Posselt utilized a system of clutches and flags to record the motion of the mandible. His work laid the foundation for understanding mandibular dynamics and occlusion.
  • Recording Method: The original recordings were conducted outside of the mouth, which magnified the vertical dimension of movement but did not accurately represent the horizontal dimension.

B. Modern Techniques

  • Digital Recording: Advances in technology have allowed for the use of digital computer techniques to record mandibular motion in real-time. This enables accurate measurement of movements in both vertical and horizontal dimensions.
  • Reconstruction of Motion: Modern systems can compute and visualize mandibular motion at multiple points simultaneously, providing valuable insights for clinical applications.

2. Key Points of Reference

Three significant points of reference are particularly important in the study of mandibular motion:

A. Incisor Point

  • Location: The incisor point is located on the midline of the mandible at the junction of the facial surface of the mandibular central incisors and the incisal edge.
  • Clinical Significance: This point is crucial for assessing anterior guidance and incisal function during mandibular movements.

B. Molar Point

  • Location: The molar point is defined as the tip of the mesiofacial cusp of the mandibular first molar on a specified side.
  • Clinical Significance: The molar point is important for evaluating occlusal relationships and the functional dynamics of the posterior teeth during movement.

C. Condyle Point

  • Location: The condyle point refers to the center of rotation of the mandibular condyle on the specified side.
  • Clinical Significance: Understanding the condyle point is essential for analyzing the temporomandibular joint (TMJ) function and the overall biomechanics of the mandible.

3. Clinical Implications

A. Occlusion and Function

  • Mandibular Motion: The capacity of motion of the mandible affects occlusal relationships, functional movements, and the overall health of the masticatory system.
  • Treatment Planning: Knowledge of mandibular motion is critical for orthodontic treatment, prosthodontics, and restorative dentistry, as it influences the design and placement of restorations and appliances.

B. Diagnosis and Assessment

  • Evaluation of Movement: Clinicians can use the principles established by Posselt to assess and diagnose issues related to mandibular function, such as limitations in movement or discrepancies in occlusion.

Ariston pHc Alkaline Glass Restorative

Ariston pHc is a notable dental restorative material developed by Ivoclar Vivadent in 1990. This innovative material is designed to provide both restorative and preventive benefits, particularly in the management of dental caries.

1. Introduction

  • Manufacturer: Ivoclar Vivadent (Liechtenstein)
  • Year of Introduction: 1990

2. Key Features

A. Ion Release Mechanism

  • Fluoride, Hydroxide, and Calcium Ions: Ariston pHc releases fluoride, hydroxide, and calcium ions when the pH within the restoration falls to critical levels. This release occurs in response to acidic conditions that can lead to enamel and dentin demineralization.

B. Acid Neutralization

  • Counteracting Decalcification: The ions released by Ariston pHc help neutralize acids in the oral environment, effectively counteracting the decalcification of both enamel and dentin. This property is particularly beneficial in preventing further carious activity around the restoration.

3. Material Characteristics

A. Light-Activated

  • Curing Method: Ariston pHc is a light-activated material, allowing for controlled curing and setting. This feature enhances the ease of use and application in clinical settings.

B. Bulk Thickness

  • Curing Depth: The material can be cured in bulk thicknesses of up to 4 mm, making it suitable for various cavity preparations, including larger restorations.

4. Indications for Use

A. Recommended Applications

  • Class I and II Lesions: Ariston pHc is recommended for use in Class I and II lesions in both deciduous (primary) and permanent teeth. Its properties make it particularly effective in managing carious lesions in children and adults.

5. Clinical Benefits

A. Preventive Properties

  • Remineralization Support: The release of fluoride and calcium ions not only helps in neutralizing acids but also supports the remineralization of adjacent tooth structures, enhancing the overall health of the tooth.

B. Versatility

  • Application in Various Situations: The ability to cure in bulk and its compatibility with different cavity classes make Ariston pHc a versatile choice for dental practitioners.

Wedging Techniques

Various wedging methods are employed to achieve optimal results, especially in cases involving gingival recession or wide proximal boxes. Below are descriptions of different wedging techniques, including "piggy back" wedging, double wedging, and wedge wedging.

1. Piggy Back Wedging

A. Description

  • Technique: In piggy back wedging, a second smaller wedge is placed on top of the first wedge.
  • Indication: This technique is particularly useful in patients with gingival recession, where there is a risk of overhanging restoration margins that could irritate the gingiva.

B. Purpose

  • Prevention of Gingival Overhang: The additional wedge helps to ensure that the restoration does not extend beyond the tooth surface into the gingival area, thereby preventing potential irritation and maintaining periodontal health.

2. Double Wedging

A. Description

  • Technique: In double wedging, wedges are placed from both the lingual and facial surfaces of the tooth.
  • Indication: This method is beneficial in cases where the proximal box is wide, providing better adaptation of the matrix band and ensuring a tighter seal.

B. Purpose

  • Enhanced Stability: By using wedges from both sides, the matrix band is held securely in place, reducing the risk of material leakage and improving the overall quality of the restoration.

3. Wedge Wedging

A. Description

  • Technique: In wedge wedging, a second wedge is inserted between the first wedge and the matrix band, particularly in specific anatomical situations.
  • Indication: This technique is commonly used in the maxillary first premolar, where a mesial concavity may complicate the placement of the matrix band.

B. Purpose

  • Improved Adaptation: The additional wedge helps to fill the space created by the mesial concavity, ensuring that the matrix band conforms closely to the tooth surface and providing a better seal for the restorative material.

Instrument formula

First number : It indicates width of blade (or of primary cutting edge) in 1/10 th of a millimeter (i.e. no. 10 means 1 mm blade width).

Second number :

1) It indicates primary cutting edge angle.

2) It is measured form a line parallel to the long axis of the instrument handle in clockwise centigrade. Expressed as per cent of 360� (e.g. 85 means 85% of 360 = 306�).

3)The instrument is positioned so that this number always exceeds 50. If the edge is locally perpendicular to the blade, then this number is normally omitted resulting in a three number code.

Third number : It indicates blade length in millimeter.

Fourth number :

1)Indicates blade angle relative to long axis of handle in clockwise centigrade.

2) The instrument is positioned so that this number. is always 50 or less. It becomes third number in a three number code when

2nd number is omitted.

Diagnostic Methods for Early Caries Detection

Early detection of caries is essential for effective management and treatment. Various diagnostic methods can be employed to identify caries activity at early stages:

1. Identification of Subsurface Demineralization

  • Inspection: Visual examination of the tooth surface for signs of demineralization, such as white spots or discoloration.
  • Radiographic Methods: X-rays can reveal subsurface carious lesions that are not visible to the naked eye, allowing for early intervention.
  • Dye Uptake Methods: Application of specific dyes that can penetrate demineralized areas, highlighting the extent of carious lesions.

2. Bacterial Testing

  • Microbial Analysis: Testing for the presence of specific cariogenic bacteria (e.g., Streptococcus mutans) can provide insight into the caries risk and activity level.
  • Salivary Testing: Salivary samples can be analyzed for bacterial counts, which can help assess the risk of caries development.

3. Assessment of Environmental Conditions

  • pH Measurement: Monitoring the pH of saliva can indicate the potential for demineralization. A lower pH (acidic environment) is conducive to caries development.
  • Salivary Flow: Evaluating salivary flow rates can help determine the protective capacity of saliva against caries. Reduced salivary flow can increase caries risk.
  • Salivary Buffering Capacity: The ability of saliva to neutralize acids is crucial for maintaining oral health. Assessing this capacity can provide valuable information about caries risk.

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