NEET MDS Lessons
Pedodontics
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
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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.
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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.
Anomalies of Number: problems in initiation stage
Hypodontia: 6% incidence; usually autosomal dominant (50% chance of passing to children) with variable expressivity (e.g., parent has mild while child has severe); most common missing permanent tooth (excluding 3rd molars) is Md 2nd premolar, 2nd most common is X lateral; oligodontia (at least 6 missing), and anodontia
1. Clincial implications: can interfere with function, lack of teeth → ↓ alveolar bone formation, esthetics, hard to replace in young children, implants only after growth completed, severe cases should receive genetic and systemic evaluation to see if other problems
2. Syndromes with hypodontia: Rieger syndrome, incontinentia pigmenti, Kabuki syndrome, Ellis-van Creveld syndrome, epidermolysis bullosa junctionalis, and ectodermal dysplasia (usually X-linked; sparse hair, unable to sweat, dysplastic nails)
Supernumerary teeth: aka hyperdontia; mesiodens when located in palatal midline; occur sporadically or as part of syndrome, common in cleft cases; delayed eruption often a sign that supernumeraries are preventing normal eruption
1. Multiple supernumerary teeth: cleidocranial dysplasia/dysostosis, Down’s, Apert, and Crouzon syndromes, etc.
Anomalies of Size: problems in morphodifferentiation stage
Microdontia: most commonly peg laterals; also in Down’s syndrome, hemifacial microsomia
Macrodontia: may be associated with hemifacial hypertrophy
Fusion: more common in primary dentition; union of two developing teeth
Gemination: more common in primary; incomplete division of single tooth bud → bifid crown, one pulp chamber; clinically distinguish from fusion by counting geminated tooth as one and have normal # teeth present (not in fusion)
Anomalies of Shape: errors during morphodifferentiation stage
Dens evaginatus: extra cusp in central groove/cingulum; fracture can → pulp exposure; most common in Orientals
Dens in dente: invagination of inner enamel epithelium → appearance of tooth within a tooth
Taurodontism: failure of Hertwig’s epithelial root sheath to invaginate to proper level → elongated (deep) pulp chamber, stunted roots; sporadic or associated with syndrome (e.g., amelogenesis imperfecta, Trichodento-osseous syndrome, ectodermal dysplasia)
Conical teeth: often associated with ectodermal dysplasia
Anomalies of Structure: problems during histodifferentiation, apposition, and mineralization stages
Dentinogenesis imperfecta: problem during histodifferentiation where defective dentin matrix → disorganized and atubular circumpulpal dentin; autosomal dominant inheritance; three types, one occurs with osteogenesis imperfecta (brittle bone syndrome); not sensitive despite exposed dentin; primary dentition has bulbous crowns, obliterated pulp chambers, bluish-grey or brownish-yellow teeth that are easily worn; permanent teeth often stained but can be sound
Amelogenesis imperfecta: heritable defect, independent from metabolic, syndromes, or systemic conditions (though similar defects seen with syndromes or environmental insults); four main types (hypoplastic, hypocalcified, hypomaturation, hypoplastic/hypomaturation with taurodontism); proper treatment addresses sensitivity, esthetics, VDO, caries and gingivitis prevention
Enamel hypoplasia: quantitative defect of enamel from problems in apposition stage; localized (caused by trauma) or generalized (caused by infection, metabolic disease, malnutrition, or hereditary disorders) effects; more common in malnourished children; least commonly Md incisors affected, often 1st molars; more susceptible to caries, excessive wearing → lost VDO, esthetic problems, and sensitivity to hot/cold
Enamel hypocalcification: during calcification stage
Fluorosis: excess F ingestion during calcification stage → intrinsic stain, mottled appearance, or brown staining and pitting; mild, moderate, or severe; porous enamel soaks up external stain
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.
AUTISM SPECTRUM DISORDER (ASD)
Characteristics
- Social communication deficits
- Restricted, repetitive behaviors
- Sensory sensitivities
- Need for routine and predictability
Dental Management Strategies
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Pre-visit Preparation:
- Social stories
- Visual aids
- Desensitization visits
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Environmental Modifications:
- Reduce sensory stimuli
- Maintain quiet environment
- Use weighted blankets for comfort
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Communication:
- Simple, concrete language
- Visual schedules
- Allow processing time
White Spot Lesions (Incipient Caries)
White spot lesions, also known as incipient caries, are early signs of dental caries that manifest as opaque areas on the enamel surface. These lesions are significant indicators of the demineralization process that occurs before the development of cavitated carious lesions.
Characteristics of White Spot Lesions
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Appearance:
- White spots are characterized by a high concentration of minerals and fluoride at the surface layer of the enamel, which diffracts light and creates an opacity that is clinically visible.
- These lesions typically appear as white, chalky areas on the enamel surface.
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Caries Development:
- While white spots are recognized as the first clinical evidence of developing caries, the carious process actually begins much earlier at the microscopic level.
- Demineralization of the enamel occurs before the white spot becomes visible, indicating that the caries process is ongoing.
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Influence of Fluoride:
- The presence of fluoride can positively affect the appearance and
texture of white spot lesions:
- With Fluoride: The surface of the white spot becomes smooth and shiny, indicating some degree of remineralization.
- Without Fluoride: The lesion appears rough and chalky, suggesting a higher level of demineralization and a greater risk of progression to cavitation.
- The presence of fluoride can positively affect the appearance and
texture of white spot lesions:
Clinical Considerations
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Probing:
- It is important to avoid probing the surface of white spot lesions too aggressively. Although the surface may appear intact, the underlying enamel is mineral-deficient and weak.
- Excessive probing can lead to the breakdown of these weak layers, potentially resulting in cavitation and the progression of caries.
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Management:
- Early intervention is crucial for managing white spot lesions.
Strategies may include:
- Fluoride Treatments: Application of fluoride varnishes or gels to promote remineralization.
- Dietary Counseling: Educating patients about reducing sugar intake and improving oral hygiene practices to prevent further demineralization.
- Monitoring: Regular dental check-ups to monitor the progression of white spot lesions and assess the effectiveness of preventive measures.
- Early intervention is crucial for managing white spot lesions.
Strategies may include:
Veau Classification of Clefts
The classification of clefts, particularly of the lip and palate, is essential for understanding the severity and implications of these congenital conditions. Veau proposed one of the most widely used classification systems for clefts of the lip and palate, which helps guide treatment and management strategies.
Classification of Clefts of the Lip
Veau classified clefts of the lip into four distinct classes:
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Class I:
- Description: A unilateral notching of the vermilion that does not extend into the lip.
- Implications: This is the least severe form and typically requires minimal intervention.
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Class II:
- Description: A unilateral notching of the vermilion border, with the cleft extending into the lip but not involving the floor of the nose.
- Implications: Surgical repair is usually necessary to restore the lip's appearance and function.
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Class III:
- Description: A unilateral clefting of the vermilion border of the lip that extends into the floor of the nose.
- Implications: This more severe form may require more complex surgical intervention to address both the lip and nasal deformity.
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Class IV:
- Description: Any bilateral clefting of the lip, which can be either incomplete notching or complete clefting.
- Implications: This is the most severe form and typically necessitates extensive surgical repair and multidisciplinary management.
Classification of Clefts of the Palate
Veau also divided palatal clefts into four classes:
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Class I:
- Description: Involves only the soft palate.
- Implications: Surgical intervention is often required to improve function and speech.
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Class II:
- Description: Involves both the soft and hard palates but does not include the alveolar process.
- Implications: Repair is necessary to restore normal anatomy and function.
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Class III:
- Description: Involves both the soft and hard palates and the alveolar process on one side of the pre-maxillary area.
- Implications: This condition may require more complex surgical management due to the involvement of the alveolar process.
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Class IV:
- Description: Involves both the soft and hard palates and continues through the alveolus on both sides of the premaxilla, leaving it free and often mobile.
- Implications: This is the most severe form of palatal clefting and typically requires extensive surgical intervention and ongoing management.
Submucous Clefts
- Definition: Veau did not include submucous clefts of the palate in his classification system.
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Diagnosis: Submucous clefts may be diagnosed through physical
findings, including:
- Bifid Uvula: A split or forked uvula.
- Palpable Notching: Notching at the posterior portion of the hard palate.
- Zona Pellucida: A thin, translucent membrane observed in the midline of the hard palate.
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Associated Conditions: Submucous clefts may be associated with:
- Incomplete velopharyngeal mechanism, which can lead to speech issues.
- Eustachian tube dysfunction, increasing the risk of otitis media and hearing problems.
Transpalatal Arch
The transpalatal arch (TPA) is a fixed orthodontic appliance used primarily in the maxillary arch to maintain or regain space, particularly after the loss of a primary molar or in cases of unilateral space loss. It is designed to provide stability to the molars and prevent unwanted movement.
Indications
- Unilateral Loss of Space:
- The transpalatal arch is particularly effective in cases where there is unilateral loss of space. It helps maintain the position of the remaining molar and prevents mesial movement of the adjacent teeth.
- It can also be used to maintain the arch form and provide anchorage during orthodontic treatment.
Contraindications
- Bilateral Loss of Space:
- The use of a transpalatal arch is contraindicated in cases of bilateral loss of space. In such situations, the appliance may not provide adequate support or stability, and other treatment options may be more appropriate.
Limitations/Disadvantages
- Tipping of Molars:
- One of the primary limitations of the transpalatal arch is the potential for both molars to tip together. This tipping can occur if the arch is not properly designed or if there is insufficient anchorage.
- Tipping can lead to changes in occlusion and may require additional orthodontic intervention to correct.