NEET MDS Lessons
Pedodontics
Space Maintainers: A fixed or removable appliance designed to maintain the space left by a prematurely lost tooth, ensuring proper alignment and positioning of the permanent dentition.
Importance of Primary Teeth
- Primary teeth serve as the best space maintainers for the permanent dentition. Their presence is crucial for guiding the eruption of permanent teeth and maintaining arch integrity.
Consequences of Space Loss
When a tooth is lost prematurely, the space can change significantly within a six-month period, leading to several complications:
- Loss of Arch Length: This can result in crowding of the permanent dentition.
- Impaction of Permanent Teeth: Teeth may become impacted if there is insufficient space for their eruption.
- Esthetic Problems: Loss of space can lead to visible gaps or misalignment, affecting a child's smile.
- Malocclusion: Improper alignment of teeth can lead to functional issues and bite problems.
Indications for Space Maintainers
Space maintainers are indicated in the following situations:
- If the space shows signs of closing.
- If using a space maintainer will simplify future orthodontic treatment.
- If treatment for malocclusion is not indicated at a later date.
- When the space needs to be maintained for two years or more.
- To prevent supra-eruption of opposing teeth.
- To improve the masticatory system and restore dental health.
Contraindications for Space Maintainers
Space maintainers should not be used in the following situations:
- If radiographs show that the succedaneous tooth will erupt soon.
- If one-third of the root of the succedaneous tooth is already calcified.
- When the space left is greater than what is needed for the permanent tooth, as indicated radiographically.
- If the space shows no signs of closing.
- When the succedaneous tooth is absent.
Classification of Space Maintainers
Space maintainers can be classified into two main categories:
1. Fixed Space Maintainers
- These are permanently attached to the teeth and cannot be removed
by the patient. Examples include band and loop space maintainers.
Common types include:
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Band and Loop Space Maintainer:
- A metal band is placed around an adjacent tooth, and a wire loop extends into the space of the missing tooth. This is commonly used for maintaining space after the loss of a primary molar.
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Crown and Loop Space Maintainer:
- Similar to the band and loop, but a crown is placed on the adjacent tooth instead of a band. This is used when the adjacent tooth requires a crown.
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Distal Shoe Space Maintainer:
- This is used when a primary second molar is lost before the eruption of the permanent first molar. It consists of a metal band on the first molar with a metal extension (shoe) that guides the eruption of the permanent molar.
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Transpalatal Arch:
- A fixed appliance that connects the maxillary molars across the palate. It is used to maintain space and prevent molar movement.
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Nance Appliance:
- Similar to the transpalatal arch, but it has a small acrylic button that rests against the anterior palate. It is used to maintain space in the upper arch.
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2. Removable Space Maintainers
- These can be taken out by the patient and are typically used when more
than one tooth is lost. They can also serve to replace occlusal function and
improve esthetics.
Common types include:
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Removable Partial Denture:
- A prosthetic device that replaces one or more missing teeth and can be removed by the patient. It can help maintain space and restore function and esthetics.
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Acrylic Space Maintainer:
- A simple acrylic appliance that can be used to maintain space. It is often used in cases where esthetics are a concern.
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Functional Space Maintainers:
- These are designed to provide occlusal function while maintaining space. They may include components that allow for chewing and speaking.
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Types of Removable Space Maintainers
- Non-functional: Typically used when more than one tooth is lost.
- Functional: Designed to provide occlusal function.
Advantages of Removable Space Maintainers
- Easy to clean and maintain proper oral hygiene.
- Maintains vertical dimension.
- Can be worn part-time, allowing circulation of blood to soft tissues.
- Creates room for permanent teeth.
- Helps prevent the development of tongue thrust habits into the extraction space.
Disadvantages of Removable Space Maintainers
- May be lost or broken by the patient.
- Uncooperative patients may not wear the appliance.
- Lateral jaw growth may be restricted if clasps are incorporated.
- May cause irritation of the underlying soft tissues.
The American Academy of Pediatric Dentistry (AAPD) Caries Risk Assessment
Tool is designed to evaluate a child's risk of developing dental caries
(cavities). The tool considers various factors to categorize a child's risk
level as low, moderate, or high.
Low Risk:
- No carious (cavitated) teeth in the past 24 months
- No enamel white spot lesions (initial stages of tooth decay)
- No visible dental plaque
- Low incidence of gingivitis (mild gum inflammation)
- Optimal exposure to fluoride (both systemic and topical)
- Limited consumption of simple sugars (at meal times only)
Moderate Risk:
- Carious teeth in the past 12 to 24 months
- One area of white spot lesion
- Gingivitis present
- Suboptimal systemic fluoride exposure (e.g., not receiving fluoride
supplements or living in a non-fluoridated water area)
- One or two between-meal exposures to simple sugars
High Risk:
- Carious teeth in the past 12 months
- More than one area of white spot lesion
- Visible dental plaque
- Suboptimal topical fluoride exposure (not using fluoridated toothpaste or
receiving professional fluoride applications)
- Presence of enamel hypoplasia (developmental defect of enamel)
- Wearing orthodontic or dental appliances that may increase caries risk
- Active caries in the mother, which can increase the child's risk due to oral
bacteria transmission
- Three or more between-meal exposures to simple sugars
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.
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.
Hypophosphatasia in Children
Hypophosphatasia is a rare genetic disorder characterized by defective mineralization of bones and teeth due to a deficiency in alkaline phosphatase, an enzyme crucial for bone mineralization. This condition can lead to various dental and skeletal abnormalities, particularly in children.
Clinical Findings
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Premature Exfoliation of Primary Teeth:
- One of the hallmark clinical findings in children with hypophosphatasia is the premature loss of anterior primary teeth.
- This loss is associated with deficient cementum, which is the tissue that helps anchor teeth to the alveolar bone.
- Teeth may be lost spontaneously or as a result of minor trauma, highlighting the fragility of the dental structures in affected children.
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Absence of Severe Gingival Inflammation:
- Unlike other dental conditions that may cause tooth mobility or loss, severe gingival inflammation is typically absent in hypophosphatasia.
- This absence can help differentiate hypophosphatasia from other periodontal diseases that may present with similar symptoms.
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Limited Alveolar Bone Loss:
- The loss of alveolar bone associated with hypophosphatasia may be localized, often limited to the anterior region where the primary teeth are affected.
Pathophysiology
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Deficient Alkaline Phosphatase Activity:
- The disease is characterized by improper mineralization of bone and teeth due to deficient alkaline phosphatase activity in various tissues, including serum, liver, bone, and kidney (tissue nonspecific).
- This deficiency leads to inadequate mineralization, resulting in the clinical manifestations observed in affected individuals.
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Increased Urinary Phosphoethanolamine:
- Patients with hypophosphatasia often exhibit elevated levels of urinary phosphoethanolamine, which can serve as a biochemical marker for the condition.
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.
Indirect Pulp Capping
Indirect pulp capping is a dental procedure designed to treat teeth with deep carious lesions that are close to the pulp but do not exhibit pulp exposure. The goal of this treatment is to preserve the vitality of the pulp while allowing for the formation of secondary dentin, which can help protect the pulp from further injury and infection.
Procedure Overview
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Initial Appointment:
During the first appointment, the dentist excavates all superficial carious dentin. However, any dentin that is affected but not infected (i.e., it is still healthy enough to maintain pulp vitality) is left intact if it is close to the pulp. This is crucial because leaving a thin layer of affected dentin can help protect the pulp from exposure and further damage. -
Pulp Dressing:
After the excavation, a pulp dressing is placed over the remaining affected dentin. Common materials used for this dressing include:- Calcium Hydroxide: Promotes the formation of secondary dentin and has antibacterial properties.
- Glass Ionomer Materials: Provide a good seal and release fluoride, which can help in remineralization.
- Hybrid Ionomer Materials: Combine properties of both glass ionomer and resin-based materials.
The tooth is then sealed temporarily, and the patient is scheduled for a follow-up appointment, typically within 6 to 12 months.
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Second Appointment:
At the second appointment, the dentist removes the temporary restoration and excavates any remaining carious material. The floor of the cavity is carefully examined for any signs of pulp exposure. If no exposure is found and the tooth has remained asymptomatic, the treatment is deemed successful. -
Permanent Restoration:
If the pulp is intact, a permanent restoration is placed. The materials used for the final restoration can vary based on the tooth's location and the clinical situation. Options include:- For Primary Dentition: Glass ionomer, hybrid ionomer, composite, compomer, amalgam, or stainless steel crowns.
- For Permanent Dentition: Composite, amalgam, stainless steel crowns, or cast crowns.
Indications for Indirect Pulp Capping
Indirect pulp capping is indicated when the following conditions are met:
- Absence of Prolonged Pain: The tooth should not have a history of prolonged or repeated episodes of pain, such as unprovoked toothaches.
- No Radiographic Evidence of Pulp Exposure: Preoperative X-rays must not show any carious penetration into the pulp chamber.
- Absence of Pathology: There should be no evidence of furcal or periapical pathology. It is essential to assess whether the root ends are completely closed and to check for any pathological changes, especially in anterior teeth.
- No Percussive Symptoms: The tooth should not exhibit any symptoms upon percussion.
Evaluation and Restoration After Indirect Pulp Therapy
After the indirect pulp therapy, the following evaluations are crucial:
- Absence of Subjective Complaints: The patient should report no toothaches or discomfort.
- Radiographic Evaluation: After 6 to 12 months, periapical and bitewing X-rays should show deposition of new secondary dentin, indicating that the pulp is healthy and responding well to treatment.
- Final Restoration: If no pulp exposure is observed after the removal of the temporary restoration and any remaining soft dentin, a permanent restoration can be placed.