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:
-
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.
-
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:
-
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.
-
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:
-
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.
-
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.
Hypnosis in Pediatric Dentistry
Hypnosis: An altered state of consciousness characterized by heightened suggestibility, focused attention, and increased responsiveness to suggestions. It is often used to facilitate behavioral and physiological changes that are beneficial for therapeutic purposes.
- Use in Pediatrics: According to Romanson (1981), hypnosis is recognized as one of the most effective nonpharmacologic therapies for children, particularly in managing anxiety and enhancing cooperation during medical and dental procedures.
- Dental Application: In the field of dentistry, hypnosis is referred to as "hypnodontics" (Richardson, 1980) and is also known as psychosomatic therapy or suggestion therapy.
Benefits of Hypnosis in Dentistry
-
Anxiety Reduction:
- Hypnosis can significantly alleviate anxiety in children, making dental visits less stressful. This is particularly important for children who may have dental phobias or anxiety about procedures.
-
Pain Management:
- One of the primary advantages of hypnosis is its ability to reduce the perception of pain. By using focused attention and positive suggestions, dental professionals can help minimize discomfort during procedures.
-
Behavioral Modification:
- Hypnosis can encourage positive behaviors in children, such as cooperation during treatment, which can reduce the need for sedation or physical restraint.
-
Enhanced Relaxation:
- The hypnotic state promotes deep relaxation, helping children feel more at ease in the dental environment.
Mechanism of Action
- Suggestibility: During hypnosis, children become more open to suggestions, allowing the dentist to guide their thoughts and feelings about the dental procedure.
- Focused Attention: The child’s attention is directed away from the dental procedure and towards calming imagery or positive thoughts, which helps reduce anxiety and discomfort.
Implementation in Pediatric Dentistry
-
Preparation:
- Prior to the procedure, the dentist should explain the process of hypnosis to both the child and their parents, addressing any concerns and ensuring understanding.
-
Induction:
- The dentist may use various techniques to induce a hypnotic state, such as guided imagery, progressive relaxation, or verbal suggestions.
-
Suggestion Phase:
- Once the child is in a relaxed state, the dentist can provide positive suggestions related to the procedure, such as feeling calm, relaxed, and pain-free.
-
Post-Hypnosis:
- After the procedure, the dentist should gradually bring the child out of the hypnotic state, reinforcing positive feelings and experiences.
Polycarbonate Crowns in Pedodontics
Polycarbonate crowns are commonly used in pediatric dentistry, particularly for managing anterior teeth affected by nursing bottle caries. These crowns serve as temporary fixed prostheses for primary teeth, providing a functional and aesthetic solution until the natural teeth exfoliate. This lecture will discuss the indications, contraindications, and advantages of polycarbonate crowns in pedodontic practice.
Nursing Bottle Caries
- Definition: Nursing bottle caries, also known as early childhood caries, is a condition characterized by the rapid demineralization of the anterior teeth, primarily affecting the labial surfaces.
- Progression: The lesions begin on the labial face of the anterior teeth and can lead to extensive demineralization, affecting the entire surface of the teeth.
- Management Goal: The primary objective is to stabilize the lesions without attempting a complete reconstruction of the coronal anatomy.
Treatment Approach
-
Preparation of the Lesion:
- The first step involves creating a clean periphery around the carious lesion using a small round bur.
- Care should be taken to leave the central portion of the affected dentin intact to avoid pulp exposure.
- This preparation allows for effective ion exchange with glass ionomer materials, facilitating a good seal.
-
Use of Polycarbonate Crowns:
- Polycarbonate crowns are indicated as temporary crowns for deciduous anterior teeth that will eventually exfoliate.
- They provide a protective covering for the tooth while maintaining aesthetics and function.
Contraindications for Polycarbonate Crowns
Polycarbonate crowns may not be suitable in certain situations, including:
- Severe Bruxism: Excessive grinding can lead to premature failure of the crown.
- Deep Bite: A deep bite may cause undue stress on the crown, leading to potential fracture or dislodgment.
- Excessive Abrasion: High levels of wear can compromise the integrity of the crown.
Advantages of Polycarbonate Crowns
Polycarbonate crowns offer several benefits in pediatric dentistry:
- Time-Saving: The application of polycarbonate crowns is relatively quick, making them efficient for both the clinician and the patient.
- Ease of Trimming: These crowns can be easily trimmed to achieve the desired fit and contour.
- Adjustability: They can be adjusted with pliers, allowing for modifications to ensure proper seating and comfort for the patient.
Behavioral Traits Associated with Parenting Styles
Various behavioral traits that can be associated with different parenting styles:
- Overprotective: Children may become dominant, shy, submissive, or anxious due to excessive protection.
- Overindulgent: This can lead to aggressive, demanding behavior, and frequent temper tantrums, but may also foster affectionate traits.
- Rejecting: Children may appear well-behaved but can struggle with cooperation, often being shy and crying easily.
- Authoritarian: This style may result in aggressive, overactive, and disobedient behavior, with children being evasive and dawdling.
Classification of Cerebral Palsy
Cerebral palsy (CP) is a group of neurological disorders that affect movement, muscle tone, and motor skills. The classification of cerebral palsy is primarily based on the type of neuromuscular dysfunction observed in affected individuals. Below is an outline of the main types of cerebral palsy, along with their basic characteristics.
1. Spastic Cerebral Palsy (Approximately 70% of Cases)
- Definition: Characterized by hypertonicity (increased muscle tone) and exaggerated reflexes.
- Characteristics:
- A. Hyperirritability of Muscles: Involved muscles exhibit exaggerated contractions when stimulated.
- B. Tense, Contracted Muscles:
- Example: Spastic Hemiplegia affects one side of the body, with the affected hand and arm flexed against the trunk. The leg may be flexed and internally rotated, leading to a limping gait with circumduction of the affected leg.
- C. Limited Neck Control: Difficulty controlling neck muscles results in head rolling.
- D. Trunk Muscle Control: Lack of control in trunk muscles leads to difficulties in maintaining an upright posture.
- E. Coordination Issues: Impaired coordination of
intraoral, perioral, and masticatory muscles can result in:
- Impaired chewing and swallowing
- Excessive drooling
- Persistent spastic tongue thrust
- Speech impairments
2. Dyskinetic Cerebral Palsy (Athetosis and Choreoathetosis) (Approximately 15% of Cases)
- Definition: Characterized by constant and uncontrolled movements.
- Characteristics:
- A. Uncontrolled Motion: Involved muscles exhibit constant, uncontrolled movements.
- B. Athetoid Movements: Slow, twisting, or writhing involuntary movements (athetosis) or quick, jerky movements (choreoathetosis).
- C. Neck Muscle Involvement: Excessive head movement due to hypertonicity of neck muscles, which may cause the head to be held back, with the mouth open and tongue protruded.
- D. Jaw Involvement: Frequent uncontrolled jaw movements or severe bruxism (teeth grinding).
- E. Hypotonicity of Perioral Musculature:
- Symptoms include mouth breathing, tongue protrusion, and excessive drooling.
- F. Facial Grimacing: Involuntary facial expressions may occur.
- G. Chewing and Swallowing Difficulties: Challenges in these areas are common.
- H. Speech Problems: Communication difficulties may arise.
3. Ataxic Cerebral Palsy (Approximately 5% of Cases)
- Definition: Characterized by poor coordination and balance.
- Characteristics:
- A. Incomplete Muscle Contraction: Involved muscles do not contract completely, leading to partial voluntary movements.
- B. Poor Balance and Coordination: Individuals may exhibit a staggering or stumbling gait and difficulty grasping objects.
- C. Tremors: Possible tremors or uncontrollable trembling when attempting voluntary tasks.
4. Mixed Cerebral Palsy (Approximately 10% of Cases)
- Definition: A combination of characteristics from more than one type of cerebral palsy.
- Example: Mixed spastic-athetoid quadriplegia, where features of both spastic and dyskinetic types are present.
Growth Theories
Understanding the growth of craniofacial structures is crucial in pedodontics, as it directly influences dental development, occlusion, and treatment planning. Various growth theories have been proposed to explain the mechanisms behind craniofacial growth, each with its own assumptions and clinical implications.
Growth Theories Overview
1. Genetic Theory (Brodle, 1941)
- Assumption: Genes control all aspects of growth.
- Application: While genetic factors play a role, external factors significantly modify growth, reducing the sole impact of genetics. Inheritance is polygenic, influencing predispositions such as Class III malocclusion.
2. Scott’s Hypothesis (1953)
- Assumption: Cartilage has innate growth potential, which is later replaced by bone.
- Application:
- Mandibular growth is likened to long bone growth, with the condyles acting as diaphysis.
- Recent studies suggest that condylar growth is primarily reactive rather than innate.
- Maxillary growth is attributed to the translation of the nasomaxillary complex.
3. Sutural Dominance Theory (Sicher, 1955)
- Assumption: Sutural connective tissue proliferation leads to appositional growth.
- Application:
- Maxillary growth is explained by pressure from sutural growth.
- Limitations include inability to explain:
- Lack of growth in suture transplantation.
- Growth in cleft palate cases.
- Sutural responses to external influences.
4. Moss’s Functional Theory (1962)
- Assumption: Functional matrices (capsular and periosteal) control craniofacial growth, with bone responding passively.
- Application:
- Examples include excessive cranial vault growth in hydrocephalus cases, illustrating the influence of functional matrices on bone growth.
5. Van Limborgh’s Theory (1970)
- Assumption: Skeletal morphogenesis is influenced by:
- Intrinsic genetic factors
- Local epigenetic factors
- General epigenetic factors
- Local environmental factors
- General environmental factors
- Application:
- Highlights the interaction between genetic and environmental factors, emphasizing that muscle and soft tissue growth also has a genetic component.
- Predicting facial dimensions based on parental studies is limited due to the polygenic and multifactorial nature of growth.
6. Petrovic’s Hypothesis (1974, Cybernetics)
- Assumption: Primary cartilage growth is influenced by differentiation of chondroblasts, while secondary cartilage has both direct and indirect effects on growth.
- Application:
- Explains the action of functional appliances on the condyle.
- The upper arch serves as a mold for the lower arch, facilitating optimal occlusion.
7. Neurotropism (Behrents, 1976)
- Assumption: Nerve impulses, through axoplasmic transport, have direct growth potential and influence soft tissue growth indirectly.
- Application:
- The effect of neurotropism on growth is reported to be negligible, suggesting limited clinical implications.
Clinical Implications
Understanding these growth theories is essential for pediatric dentists in several ways:
- Diagnosis and Treatment Planning: Knowledge of growth patterns aids in diagnosing malocclusions and planning orthodontic interventions.
- Timing of Interventions: Recognizing the stages of growth can help in timing treatments such as extractions, space maintainers, and orthodontic appliances.
- Predicting Growth Outcomes: Awareness of genetic and environmental influences can assist in predicting treatment outcomes and managing patient expectations.