NEET MDS Lessons
Pedodontics
Pit and Fissure Sealants
Pit and fissure sealants are preventive dental materials used to protect occlusal surfaces of teeth from caries by sealing the grooves and pits that are difficult to clean. According to Mitchell and Gordon (1990), sealants can be classified based on several criteria, including polymerization methods, resin systems, filler content, and color.
Classification of Pit and Fissure Sealants
1. Polymerization Methods
Sealants can be differentiated based on how they harden or polymerize:
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a) Self-Activation (Mixing Two Components)
- These sealants harden through a chemical reaction that occurs when two components are mixed together. This method does not require any external light source.
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b) Light Activation
- Sealants that require a light source to initiate the polymerization
process can be further categorized into generations:
- First Generation: Ultraviolet Light
- Utilizes UV light for curing, which can be less common due to safety concerns.
- Second Generation: Self-Cure
- These sealants harden through a chemical reaction without the need for light, similar to self-activating sealants.
- Third Generation: Visible Light
- Cured using visible light, which is more user-friendly and safer than UV light.
- Fourth Generation: Fluoride-Releasing
- These sealants not only provide a physical barrier but also release fluoride, which can help in remineralizing enamel and providing additional protection against caries.
- First Generation: Ultraviolet Light
- Sealants that require a light source to initiate the polymerization
process can be further categorized into generations:
2. Resin System
The type of resin used in sealants can also classify them:
- BIS-GMA (Bisphenol A Glycidyl Methacrylate)
- A commonly used resin that provides good mechanical properties and adhesion.
- Urethane Acrylate
- Offers enhanced flexibility and durability, making it suitable for areas subject to stress.
3. Filled and Unfilled
Sealants can be categorized based on the presence of fillers:
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Filled Sealants
- Contain added particles that enhance strength and wear resistance. They may provide better wear characteristics but can be more viscous and difficult to apply.
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Unfilled Sealants
- Typically have a smoother flow and are easier to apply, but may not be as durable as filled sealants.
4. Clear or Tinted
The color of the sealant can also influence its application:
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Clear Sealants
- Have better flow characteristics, allowing for easier penetration into pits and fissures. They are less visible, which can be a disadvantage in monitoring during follow-up visits.
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Tinted Sealants
- Easier for both patients and dentists to see, facilitating monitoring and assessment during recalls. However, they may have slightly different flow characteristics compared to clear sealants.
Application Process
- Sealants are applied in a viscous liquid state that enters the micropores of the tooth surface, which have been enlarged through acid conditioning.
- Once applied, the resin hardens due to either a self-hardening catalyst or the application of a light source.
- The extensions of the hardened resin that penetrate and fill the micropores are referred to as "tags," which help in retaining the sealant on the tooth surface.
Behavioral Classification Systems in Pediatric Dentistry
Understanding children's behavior in the dental environment is crucial for effective treatment and management. Various classification systems have been developed to categorize these behaviors, which can assist dentists in guiding their approach, systematically recording behaviors, and evaluating research validity.
Importance of Behavioral Classification
- Behavior Guidance: Knowledge of behavioral classification systems helps dentists tailor their behavior guidance strategies to individual children.
- Systematic Recording: These systems provide a structured way to document children's behaviors during dental visits, facilitating better communication and understanding among dental professionals.
- Research Evaluation: Behavioral classifications can aid in assessing the validity of current research and practices in pediatric dentistry.
Wright’s Clinical Classification
Wright’s clinical classification categorizes children into three main groups based on their cooperative abilities:
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Cooperative:
- Children in this category exhibit positive behavior and are generally relaxed during dental visits. They may show enthusiasm and can be treated using straightforward behavior-shaping approaches. These children typically follow established guidelines and perform well within the framework provided.
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Lacking in Cooperative Ability:
- This group includes children who demonstrate significant difficulties in cooperating during dental procedures. They may require additional support and alternative strategies to facilitate treatment.
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Potentially Cooperative:
- Children in this category may show some willingness to cooperate but may also exhibit signs of apprehension or reluctance. They may need encouragement and reassurance to engage positively in the dental environment.
Frankl Behavioral Rating Scale
The Frankl behavioral rating scale is a widely used tool that divides observed behavior into four categories, ranging from definitely positive to definitely negative. The scale is as follows:
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Rating 1: Definitely Negative:
- Characteristics: Refusal of treatment, forceful crying, fearfulness, or any other overt evidence of extreme negativity.
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Rating 2: Negative:
- Characteristics: Reluctance to accept treatment, uncooperativeness, and some evidence of a negative attitude (e.g., sullen or withdrawn behavior).
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Rating 3: Positive:
- Characteristics: Acceptance of treatment with cautious behavior at times; willingness to comply with the dentist, albeit with some reservations. The patient generally follows the dentist’s directions cooperatively.
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Rating 4: Definitely Positive:
- Characteristics: Good rapport with the dentist, interest in dental procedures, and expressions of enjoyment (e.g., laughter).
Application of the Frankl Scale
- Research Tool: The Frankl method is popular in research settings for assessing children's behavior in dental contexts.
- Shorthand Recording: Dentists can use shorthand notations (e.g., “+” for positive behavior, “-” for negative behavior) to quickly document children's responses during visits.
- Limitations: While the scale is useful, it may not provide sufficient clinical information regarding uncooperative children. For example, simply recording “-” does not convey the nuances of a child's behavior. A more descriptive notation, such as “- tearful,” offers better insight into the clinical problem.
Phenytoin-Induced Gingival Overgrowth
- Phenytoin (Dilantin):
- An anticonvulsant medication primarily used in the treatment of epilepsy.
- First introduced in 1938 by Merrit and Putnam.
Gingival Hyperplasia
- Gingival hyperplasia refers to the overgrowth of gum tissue, which can lead to aesthetic concerns and functional issues, such as difficulty in maintaining oral hygiene.
- Historical Context:
- The association between phenytoin therapy and gingival hyperplasia was first reported by Kimball in 1939.
- In his study, 57% of 119 patients taking phenytoin for seizure control experienced some degree of gingival overgrowth.
Mechanism of Gingival Overgrowth
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Fibroblast Activity:
- Early research indicated an increase in the number of fibroblasts in the gingival tissues of patients receiving phenytoin.
- This led to the initial terminology of "Dilantin hyperplasia."
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Current Understanding:
- Subsequent studies, including those by Hassell and colleagues, have shown that true hyperplasia does not exist in this condition.
- Findings indicate:
- There is no excessive collagen accumulation per unit of tissue.
- Fibroblasts do not appear abnormal in number or size.
- As a result, the term phenytoin-induced gingival overgrowth is now preferred, as it more accurately reflects the condition.
Clinical Implications
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Management:
- Patients on phenytoin should be monitored for signs of gingival overgrowth, especially if they have poor oral hygiene or other risk factors.
- Dental professionals should educate patients about maintaining good oral hygiene practices to minimize the risk of gingival overgrowth.
- In cases of significant overgrowth, treatment options may include:
- Improved oral hygiene measures.
- Professional dental cleanings.
- Surgical intervention (gingivectomy) if necessary.
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Patient Education:
- It is important to inform patients about the potential side effects of phenytoin, including gingival overgrowth, and the importance of regular dental check-ups.
Classification of Early Childhood Caries (ECC)
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Type 1 ECC (Mild to Moderate)
- Affects molars and incisors
- Typically seen in children aged 2-5 years
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Type 2 ECC (Moderate to Severe)
- Characterized by labiolingual caries affecting maxillary incisors, with or without molar involvement
- Usually observed soon after the first tooth erupts
- Mandibular incisors remain unaffected
- Often caused by inappropriate bottle feeding
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Type 3 ECC (Severe)
- Involves all primary teeth
- Commonly seen in children aged 3-5 years
Xylitol and Its Role in Dental Health
Xylitol is a naturally occurring sugar alcohol that is widely recognized for its potential benefits in dental health, particularly in the prevention of dental caries.
Properties of Xylitol
- Low-Calorie Sweetener: Xylitol is a low-calorie sugar substitute that provides sweetness without the high caloric content of traditional sugars.
- Natural Occurrence: It is found in small amounts in various fruits and vegetables and can also be produced from birch wood and corn.
Mechanism of Action
- Inhibition of Streptococcus mutans:
- Xylitol has been shown to inhibit the growth of Streptococcus mutans, the primary bacterium responsible for dental caries.
- It disrupts the metabolism of these bacteria, reducing their ability to produce acids that demineralize tooth enamel.
Research and Evidence
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Studies by Makinen:
- Dr. R. Makinen has conducted extensive research on xylitol, collaborating with various researchers worldwide.
- In 2000, he published a summary titled “The Rocky Road of Xylitol to its Clinical Application,” which highlighted the challenges and successes in the clinical application of xylitol.
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Caries Activity Reduction:
- Numerous studies indicate that xylitol chewing gum significantly reduces caries activity in both children and adults.
- The evidence suggests that regular use of xylitol can lead to a decrease in the incidence of cavities.
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Transmission of S. mutans:
- Research has shown that xylitol chewing gum can decrease the transmission of S. mutans from mothers to their children, potentially reducing the risk of early childhood caries.
Applications of Xylitol
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Incorporation into Foods and Dentifrices:
- Xylitol has been tested as an additive in various food products and dental care items, including toothpaste and mouth rinses.
- Its sweetening properties make it an appealing option for children, promoting compliance with oral health recommendations.
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Popularity as a Caries Prevention Strategy:
- The use of xylitol chewing gum is gaining traction as an effective caries prevention strategy, particularly among children.
- Its palatable taste and low-calorie nature make it an attractive alternative to traditional sugary snacks.
Piaget's Cognitive Theory
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Active Learning:
- Piaget believed that children are not merely influenced by their environment; instead, they actively engage with it. They construct their understanding of the world through experiences and interactions.
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Adaptation:
- Adaptation is the process through which individuals adjust their cognitive structures to better understand their environment. This process consists of three functional variants: assimilation, accommodation, and equilibration.
The Three Functional Variants of Adaptation
i. Assimilation:
- Definition: Assimilation involves incorporating new information or experiences into existing cognitive schemas (mental frameworks). It is the process of recognizing and relating new objects or experiences to what one already knows.
- Example: A child who knows what a dog is may see a new breed of dog and recognize it as a dog because it fits their existing schema of "dog."
ii. Accommodation:
- Definition: Accommodation occurs when new information cannot be assimilated into existing schemas, leading to a modification of those schemas or the creation of new ones. It accounts for changing concepts and strategies in response to new experiences.
- Example: If the same child encounters a cat for the first time, they may initially try to assimilate it into their "dog" schema. However, upon realizing that it is not a dog, they must accommodate by creating a new schema for "cat."
iii. Equilibration:
- Definition: Equilibration is the process of balancing assimilation and accommodation to create stable understanding. It refers to the ongoing adjustments that individuals make to their cognitive structures to achieve a coherent understanding of the world.
- Example: When a child encounters a variety of animals, they may go through a cycle of assimilation and accommodation until they develop a comprehensive understanding of different types of animals, achieving a state of cognitive equilibrium.
Photostimulable Phosphors (PSPs) in Digital Imaging
- Photostimulable phosphors (PSPs), also known as storage phosphors, are materials used in digital imaging for the acquisition of radiographic images. They serve as an alternative to traditional film-based radiography.
Characteristics of PSPs
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Storage Mechanism: Unlike conventional screen materials used in panoramic or cephalometric imaging, PSPs do not fluoresce immediately upon exposure to x-ray photons. Instead, they capture and store the incoming x-ray photon information as a latent image.
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Latent Image: The latent image is similar to that found in traditional film radiography, where the image is not visible until processed.
Image Acquisition Process
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Exposure:
- The PSP plate is exposed to x-rays, which causes the phosphor material to absorb and store the energy from the x-ray photons.
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Scanning:
- After exposure, the PSP plate is scanned by a laser beam in a drum scanner. This process is crucial for retrieving the stored image information.
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Energy Release:
- The laser scanning excites the phosphor, causing it to release the stored energy as an electronic signal. This signal represents the latent image captured during the x-ray exposure.
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Digitalization:
- The electronic signal is then digitized, with various gray levels assigned to different points on the curve. This process creates the final image information that can be viewed and analyzed.
Advantages of PSP Systems
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Image Quality: PSPs can produce high-quality images with a wide dynamic range, allowing for better visualization of anatomical structures.
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Reusability: PSP plates can be reused multiple times, making them a cost-effective option for dental practices.
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Compatibility: PSP systems can be integrated into existing digital imaging workflows, providing flexibility for dental professionals.
Available PSP Imaging Systems
- Soredex: OpTime
- AirTechniques: Scan X
- Gendex: Denoptix
These systems offer various features and capabilities, allowing dental practices to choose the best option for their imaging needs.