NEET MDS Lessons
Conservative Dentistry
Surface Preparation for Mechanical Bonding
Methods for Producing Surface Roughness
- Grinding and Etching: The common methods for creating
surface roughness to enhance mechanical bonding include grinding or etching
the surface.
- Grinding: This method produces gross mechanical roughness but leaves a smear layer of hydroxyapatite crystals and denatured collagen approximately 1 to 3 µm thick.
- Etching: Etching can remove the smear layer and create a more favorable surface for bonding.
Importance of Surface Preparation
- Proper surface preparation is critical for achieving effective mechanical bonding between dental materials, ensuring the longevity and success of restorations.
Radiographic Advancements in Caries Detection
Advancements in dental technology have significantly improved the detection and quantification of dental caries. This lecture will cover several key technologies used in caries detection, including Diagnodent, infrared and red fluorescence, DIFOTI, and QLF, as well as the film speeds used in radiographic imaging.
1. Diagnodent
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Technology:
- Utilizes infrared laser fluorescence for the detection and quantification of dental caries, particularly effective for occlusal and smooth surface caries.
- Not as effective for detecting proximal caries.
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Specifications:
- Operates using red light with a wavelength of 655 nm.
- Features a fiber optic cable with a handheld probe and a diode laser light source.
- The device transmits light to the handheld probe and fiber optic tip.
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Measurement:
- Scores dental caries on a scale of 0-99.
- Fluorescence is attributed to the presence of porphyrin, a compound produced by bacteria in carious lesions.
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Scoring Criteria:
- Score 1: <15 - No dental caries; up to half of enamel intact.
- Score 2: 15-19 - Demineralization extends into the inner half of enamel or upper third of dentin.
- Score 3: >19 - Extending into the inner portion of dentin.
2. Infrared and Red Fluorescence
- Also Known As: Midwest Caries I.D. detection handpiece.
- Technology:
- Utilizes two wavelengths:
- 880 nm - Infrared
- 660 nm - Red
- Utilizes two wavelengths:
- Application:
- Designed for use over all tooth surfaces.
- Particularly useful for detecting hidden occlusal caries.
3. DIFOTI (Digital Imaging Fiber Optic Transillumination)
- Description:
- An advancement of the Fiber Optic Transillumination (FOTI) technique.
- Application:
- Primarily used for the detection of proximal caries.
- Drawback:
- Difficulty in accurately determining the depth of the lesion.
4. QLF (Quantitative Laser Fluorescence)
- Overview:
- One of the most extensively investigated techniques for early detection of dental caries, introduced in 1978.
- Effectiveness:
- Good for detecting occlusal and smooth surface caries.
- Challenging for detecting interproximal caries.
Film Speed in Radiographic Imaging
- Film Types:
- Film D: Best film for detecting incipient caries.
- Film E: Most commonly used film in dentistry for caries detection.
- Film F: Most recommended film speed for general use.
- Film C: No longer available.
Early Childhood Caries (ECC) Classification
Early Childhood Caries (ECC) is a significant public health concern characterized by the presence of carious lesions in young children. It is classified into three types based on severity, affected teeth, and underlying causes. Understanding these classifications helps in diagnosing, preventing, and managing ECC effectively.
Type I ECC (Mild to Moderate)
A. Characteristics
- Affected Teeth: Carious lesions primarily involve the molars and incisors.
- Age Group: Typically observed in children aged 2 to 5 years.
B. Causes
- Dietary Factors: The primary cause is usually a combination of cariogenic semisolid or solid foods, such as sugary snacks and beverages.
- Oral Hygiene: Lack of proper oral hygiene practices contributes significantly to the development of caries.
- Progression: As the cariogenic challenge persists, the number of affected teeth tends to increase.
C. Clinical Implications
- Management: Emphasis on improving oral hygiene practices and dietary modifications can help control and reverse early carious lesions.
Type II ECC (Moderate to Severe)
A. Characteristics
- Affected Teeth: Labio-lingual carious lesions primarily affect the maxillary incisors, with or without molar caries, depending on the child's age.
- Age Group: Typically seen soon after the first tooth erupts.
B. Causes
- Feeding Practices: Common causes include inappropriate use of feeding bottles, at-will breastfeeding, or a combination of both.
- Oral Hygiene: Poor oral hygiene practices exacerbate the condition.
- Progression: If not controlled, Type II ECC can progress to more advanced stages of caries.
C. Clinical Implications
- Intervention: Early intervention is crucial, including education on proper feeding practices and oral hygiene to prevent further carious development.
Type III ECC (Severe)
A. Characteristics
- Affected Teeth: Carious lesions involve almost all teeth, including the mandibular incisors.
- Age Group: Usually observed in children aged 3 to 5 years.
B. Causes
- Multifactorial: The etiology is a combination of various factors, including poor oral hygiene, dietary habits, and possibly socio-economic factors.
- Rampant Nature: This type of ECC is rampant and can affect immune tooth surfaces, leading to extensive decay.
C. Clinical Implications
- Management: Requires comprehensive dental treatment, including restorative procedures and possibly extractions. Education on preventive measures and regular dental visits are essential to manage and prevent recurrence.
Pit and Fissure Sealants
Pit and fissure sealants are preventive dental materials applied to the occlusal surfaces of teeth to prevent caries in the pits and fissures. These sealants work by filling in the grooves and depressions on the tooth surface, thereby eliminating the sheltered environment where bacteria can thrive and cause decay.
Classification
Mitchell and Gordon (1990) classified pit and fissure sealants based on their composition and properties. While the specific classification details are not provided in the prompt, sealants can generally be categorized into:
- Resin-Based Sealants: These are the most common type, made from composite resins that provide good adhesion and durability.
- Glass Ionomer Sealants: These sealants release fluoride and bond chemically to the tooth structure, providing additional protection against caries.
- Polyacid-Modified Resin Sealants: These combine properties of both resin and glass ionomer sealants, offering improved adhesion and fluoride release.
Requisites of an Efficient Sealant
For a pit and fissure sealant to be effective, it should possess the following characteristics:
- Viscosity: The sealant should be viscous enough to penetrate deep into pits and fissures.
- Adequate Working Time: Sufficient time for application and manipulation before curing.
- Low Sorption and Solubility: The material should have low water sorption and solubility to maintain its integrity in the oral environment.
- Rapid Cure: Quick curing time to allow for efficient application and patient comfort.
- Good Adhesion: Strong and prolonged adhesion to enamel to prevent microleakage.
- Wear Resistance: The sealant should withstand the forces of mastication without wearing away.
- Minimum Tissue Irritation: The material should be biocompatible and cause minimal irritation to oral tissues.
- Cariostatic Action: Ideally, the sealant should have properties that inhibit the growth of caries-causing bacteria.
Indications for Use
Pit and fissure sealants are indicated in the following situations:
- Newly Erupted Teeth: Particularly primary molars and permanent premolars and molars that have recently erupted (within the last 4 years).
- Open or Sticky Pits and Fissures: Teeth with pits and fissures that are not well coalesced and may trap food particles.
- Stained Pits and Fissures: Teeth with stained pits and fissures showing minimal decalcification.
Contraindications for Use
Pit and fissure sealants should not be used in the following situations:
- No Previous Caries Experience: Teeth that have no history of caries and have well-coalesced pits and fissures.
- Self-Cleansable Pits and Fissures: Wide pits and fissures that can be effectively cleaned by normal oral hygiene.
- Caries-Free for Over 4 Years: Teeth that have been caries-free for more than 4 years.
- Proximal Caries: Presence of caries on proximal surfaces, either clinically or radiographically.
- Partially Erupted Teeth: Teeth that cannot be adequately isolated during the sealing process.
Key Points for Sealant Application
Age Range for Sealant Application
- 3-4 Years of Age: Application is recommended for newly erupted primary molars.
- 6-7 Years of Age: First permanent molars typically erupt during this age, making them prime candidates for sealant application.
- 11-13 Years of Age: Second permanent molars and premolars should be considered for sealants as they erupt.
Composite Cavity Preparation
Composite cavity preparations are designed to optimize the placement and retention of composite resin materials in restorative dentistry. There are three basic designs for composite cavity preparations: Conventional, Beveled Conventional, and Modified. Each design has specific characteristics and indications based on the clinical situation.
1. Conventional Preparation Design
A. Characteristics
- Design: Similar to cavity preparations for amalgam restorations.
- Shape: Box-like cavity with slight occlusal convergence, flat floors, and undercuts in dentin.
- Cavosurface Angle: Near 90° (butt joint), which provides a strong interface for the restoration.
B. Indications
- Moderate to Large Class I and Class II Restorations: Suitable for larger cavities where significant tooth structure is missing.
- Replacement of Existing Amalgam: When an existing amalgam restoration needs to be replaced, a conventional preparation is often indicated.
- Class II Cavities Extending onto the Root: In cases where the cavity extends onto the root, a conventional design is preferred to ensure adequate retention and support.
2. Beveled Conventional Preparation
A. Characteristics
- Enamel Cavosurface Bevel: Incorporation of a bevel at the enamel margin to increase surface area for bonding.
- End-on-Etching: The bevel allows for more effective etching of the enamel rods, enhancing adhesion.
- Benefits:
- Improves retention of the composite material.
- Reduces microleakage at the restoration interface.
- Strengthens the remaining tooth structure.
B. Preparation Technique
- Bevel Preparation: The bevel is created using a flame-shaped diamond instrument, approximately 0.5 mm wide and angled at 45° to the external enamel surface.
C. Indications
- Large Area Restorations: Ideal for restoring larger areas of tooth structure.
- Replacing Existing Restorations: Suitable for class III, IV, and VI cavities where composite is used to replace older restorations.
- Rarely Used for Posterior Restorations: While effective, this design is less commonly used for posterior teeth due to aesthetic considerations.
3. Modified Preparation
A. Characteristics
- Depth of Preparation: Does not routinely extend into dentin; the depth is determined by the extent of the carious lesion.
- Wall Configuration: No specified wall configuration, allowing for flexibility in design.
- Conservation of Tooth Structure: Aims to conserve as much tooth structure as possible while obtaining retention through micro-mechanical means (acid etching).
- Appearance: Often has a scooped-out appearance, reflecting its conservative nature.
B. Indications
- Small Cavitated Carious Lesions: Best suited for small carious lesions that are surrounded by enamel.
- Correcting Enamel Defects: Effective for addressing minor enamel defects without extensive preparation.
C. Modified Preparation Designs
- Class III (A and B): For anterior teeth, focusing on small defects or carious lesions.
- Class IV (C and D): For anterior teeth with larger defects, ensuring minimal loss of healthy tooth structure.
Early Childhood Caries (ECC) Classification
Early Childhood Caries (ECC) is a significant public health concern characterized by the presence of carious lesions in young children. It is classified into three types based on severity, affected teeth, and underlying causes. Understanding these classifications helps in diagnosing, preventing, and managing ECC effectively.
Type I ECC (Mild to Moderate)
A. Characteristics
- Affected Teeth: Carious lesions primarily involve the molars and incisors.
- Age Group: Typically observed in children aged 2 to 5 years.
B. Causes
- Dietary Factors: The primary cause is usually a combination of cariogenic semisolid or solid foods, such as sugary snacks and beverages.
- Oral Hygiene: Lack of proper oral hygiene practices contributes significantly to the development of caries.
- Progression: As the cariogenic challenge persists, the number of affected teeth tends to increase.
C. Clinical Implications
- Management: Emphasis on improving oral hygiene practices and dietary modifications can help control and reverse early carious lesions.
Type II ECC (Moderate to Severe)
A. Characteristics
- Affected Teeth: Labio-lingual carious lesions primarily affect the maxillary incisors, with or without molar caries, depending on the child's age.
- Age Group: Typically seen soon after the first tooth erupts.
B. Causes
- Feeding Practices: Common causes include inappropriate use of feeding bottles, at-will breastfeeding, or a combination of both.
- Oral Hygiene: Poor oral hygiene practices exacerbate the condition.
- Progression: If not controlled, Type II ECC can progress to more advanced stages of caries.
C. Clinical Implications
- Intervention: Early intervention is crucial, including education on proper feeding practices and oral hygiene to prevent further carious development.
Type III ECC (Severe)
A. Characteristics
- Affected Teeth: Carious lesions involve almost all teeth, including the mandibular incisors.
- Age Group: Usually observed in children aged 3 to 5 years.
B. Causes
- Multifactorial: The etiology is a combination of various factors, including poor oral hygiene, dietary habits, and possibly socio-economic factors.
- Rampant Nature: This type of ECC is rampant and can affect immune tooth surfaces, leading to extensive decay.
C. Clinical Implications
- Management: Requires comprehensive dental treatment, including restorative procedures and possibly extractions. Education on preventive measures and regular dental visits are essential to manage and prevent recurrence.
Nursing Caries and Rampant Caries
Nursing caries and rampant caries are both forms of dental caries that can lead to significant oral health issues, particularly in children.
Nursing Caries
- Nursing Caries: A specific form of rampant caries that primarily affects infants and toddlers, characterized by a distinct pattern of decay.
Age of Occurrence
- Age Group: Typically seen in infants and toddlers, particularly those who are bottle-fed or breastfed on demand.
Dentition Involved
- Affected Teeth: Primarily affects the primary dentition, especially the maxillary incisors and molars. Notably, the mandibular incisors are usually spared.
Characteristic Features
- Decay Pattern:
- Involves maxillary incisors first, followed by molars.
- Mandibular incisors are not affected due to protective factors.
- Rapid Lesion Development: New lesions appear quickly, indicating acute decay rather than chronic neglect.
Etiology
- Feeding Practices:
- Improper feeding practices are the primary cause, including:
- Bottle feeding before sleep.
- Pacifiers dipped in honey or other sweeteners.
- Prolonged at-will breastfeeding.
- Improper feeding practices are the primary cause, including:
Treatment
- Early Detection: If detected early, nursing caries can
be managed with:
- Topical fluoride applications.
- Education for parents on proper feeding and oral hygiene.
- Maintenance: Focus on maintaining teeth until the transition to permanent dentition occurs.
Prevention
- Education: Emphasis on educating prospective and new mothers about proper feeding practices and oral hygiene to prevent nursing caries.
Rampant Caries
- Rampant Caries: A more generalized and acute form of caries that can occur at any age, characterized by widespread decay and early pulpal involvement.
Age of Occurrence
- Age Group: Can be seen at all ages, including adolescence and adulthood.
Dentition Involved
- Affected Teeth: Affects both primary and permanent dentition, including teeth that are typically resistant to decay.
Characteristic Features
- Decay Pattern:
- Involves surfaces that are usually immune to decay, including mandibular incisors.
- Rapid appearance of new lesions, indicating a more aggressive form of caries.
Etiology
- Multifactorial Causes: Rampant caries is influenced by
a combination of factors, including:
- Frequent snacking and excessive intake of sticky refined carbohydrates.
- Decreased salivary flow.
- Genetic predisposition.
Treatment
- Pulp Therapy:
- Often requires more extensive treatment, including pulp therapy for teeth with multiple pulp exposures.
- Long-term treatment may be necessary, especially when permanent dentition is involved.
Prevention
- Mass Education: Dental health education should be provided at a community level, targeting individuals of all ages to promote good oral hygiene and dietary practices.
Key Differences
Mandibular Anterior Teeth
- Nursing Caries: Mandibular incisors are spared due to:
- Protection from the tongue.
- Cleaning action of saliva, aided by the proximity of the sublingual gland ducts.
- Rampant Caries: Mandibular incisors can be affected, as this condition does not spare teeth that are typically resistant to decay.