NEET MDS Lessons
Pedodontics
1. Crown Dimensions
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Primary Anterior Teeth: The crowns of primary anterior teeth (incisors and canines) are characterized by a wider mesiodistal dimension and a shorter incisocervical height compared to their permanent counterparts. This means that primary incisors are broader from side to side and shorter from the biting edge to the gum line, giving them a more squat appearance.
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Primary Molars: The crowns of primary molars are also shorter and narrower in the mesiodistal direction at the cervical third compared to permanent molars. This results in a more constricted appearance at the base of the crown, which is important for accommodating the developing permanent teeth.
2. Root Structure
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Primary Anterior Teeth: The roots of primary anterior teeth taper more rapidly than those of permanent anterior teeth. This rapid tapering allows for a more pronounced root system that is essential for anchoring the teeth in the softer bone of children’s jaws.
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Primary Molars: In contrast, the roots of primary molars are longer and more slender than those of permanent molars. This elongation and slenderness provide stability while also allowing for the necessary space for the developing permanent teeth beneath them.
3. Enamel Characteristics
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Enamel Rod Orientation: In primary teeth, the enamel rods in the gingival third slope occlusally (toward the biting surface) rather than cervically (toward the root) as seen in permanent teeth. This unique orientation can influence the way primary teeth respond to wear and decay.
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Thickness of Enamel: The enamel on the occlusal surfaces of primary molars is of uniform thickness, measuring approximately 1 mm. In contrast, the enamel on permanent molars is thicker, averaging around 2.5 mm. This difference in thickness can affect the durability and longevity of the teeth.
4. Surface Contours
- Buccal and Lingual Surfaces: The buccal and lingual surfaces of primary molars are flatter above the crest of contour compared to permanent molars. This flatter contour can influence the way food is processed and how plaque accumulates on the teeth.
5. Root Divergence
- Primary Molars: The roots of primary molars are more divergent relative to their crown width compared to permanent molars. This divergence is crucial as it allows adequate space for the developing permanent dentition, which is essential for proper alignment and spacing in the dental arch.
6. Occlusal Features
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Occlusal Table: The occlusal table of primary molars is narrower in the faciolingual dimension. This narrower occlusal surface, combined with shallower anatomy, results in shorter cusps, less pronounced ridges, and shallower fossae. These features can affect the functional aspects of chewing and the overall occlusion.
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Mesial Cervical Ridge: Primary molars exhibit a prominent mesial cervical ridge, which serves as a distinguishing feature that helps in identifying the right and left molars during dental examinations.
7. Root Characteristics
- Root Shape and Divergence: The roots of primary molars are not only longer and more slender but also extremely narrow mesiodistally and broad lingually. This unique shape contributes to their stability while allowing for the necessary divergence and minimal curvature. Additionally, primary molars typically have little or no root trunk, which is a stark contrast to the more complex root structures of permanent molars.
Stainless Steel Crowns
Stainless steel crowns (SSCs) are a common restorative option for primary teeth, particularly in pediatric dentistry. They are especially useful for teeth with extensive carious lesions or structural damage, providing durability and protection for the underlying tooth structure.
Indications for Stainless Steel Crowns
- Primary Incisors or Canines:
- SSCs are indicated for primary incisors or canines that have extensive proximal lesions, especially when the incisal portion of the tooth is involved.
- They are particularly beneficial in cases where traditional restorative materials (like amalgam or composite) may not provide adequate strength or longevity.
Crown Selection and Preparation
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Crown Selection:
- An appropriate size of stainless steel crown is selected based on the dimensions of the tooth being restored.
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Contouring:
- The crown is contoured at the cervical margin to ensure a proper fit and to minimize the risk of gingival irritation.
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Polishing:
- The crown is polished to enhance its surface finish, which can help reduce plaque accumulation and improve esthetics.
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Cementation:
- The crown is cemented into place using a suitable dental cement, ensuring a secure fit even on teeth that have undergone significant carious structure removal.
Advantages of Stainless Steel Crowns
- Retention:
- SSCs provide excellent retention and can remain in place even when extensive portions of carious tooth structure have been removed.
- Durability:
- They are highly durable and can withstand the forces of mastication, making them ideal for primary teeth that are subject to wear and tear.
Esthetic Considerations
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Esthetic Limitations:
- One of the drawbacks of stainless steel crowns is their metallic appearance, which may not meet the esthetic requirements of some children and their parents.
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Open-Face Stainless Steel Crowns:
- To address esthetic concerns, a technique known as the open-face stainless steel crown can be employed.
- In this technique, most of the labial metal of the crown is cut away, creating a labial "window."
- This window is then restored with composite resin, allowing for a more natural appearance while still providing the strength and durability of the stainless steel crown.
Types of Crying
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Obstinate Cry:
- Characteristics: This cry is loud, high-pitched, and resembles a siren. It often accompanies temper tantrums, which may include kicking and biting.
- Emotional Response: It reflects the child's external response to anxiety and frustration.
- Physical Manifestation: Typically involves a lot of tears and convulsive sobbing, indicating a high level of distress.
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Frightened Cry:
- Characteristics: This cry is not about getting what the child wants; instead, it arises from fear that overwhelms the child's ability to reason.
- Physical Manifestation: Usually involves small whimpers, indicating a more subdued response compared to the obstinate cry.
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Hurt Cry:
- Characteristics: This cry is a reaction to physical discomfort or pain.
- Physical Manifestation: It may start with a single tear that runs down the child's cheek without any accompanying sound or resistance, indicating a more internalized response to pain.
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Compensatory Cry
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Characteristics:
- This type of cry is not a traditional cry; rather, it is a sound that the child makes in response to a specific stimulus, such as the sound of a dental drill.
- It is characterized by a constant whining noise rather than the typical crying sounds associated with distress.
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Physical Manifestation:
- There are no tears or sobs associated with this cry. The child does not exhibit the typical signs of emotional distress that accompany other types of crying.
- The sound is directly linked to the presence of the stimulus (e.g., the drill). When the stimulus stops, the whining also ceases.
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Emotional Response:
- The compensatory cry may indicate a child's attempt to cope with discomfort or fear in a situation where they feel powerless or anxious. It serves as a way for the child to express their discomfort without engaging in more overt forms of crying.
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Natal and neonatal teeth, also known by various synonyms such as congenital teeth, prediciduous teeth, dentition praecox, and foetal teeth. This topic is significant in pediatric dentistry and has implications for both diagnosis and treatment.
Etiology
The etiology of natal and neonatal teeth is multifactorial. Key factors include:
- Superficial Position of Tooth Germs: The positioning of tooth germs can lead to early eruption.
- Infection: Infections during pregnancy may influence tooth development.
- Malnutrition: Nutritional deficiencies can affect dental health.
- Eruption Acceleration: Febrile incidents or hormonal stimulation can hasten the eruption process.
- Genetic Factors: Hereditary transmission of a dominant autosomal gene may play a role.
- Osteoblastic Activities: Bone remodeling phenomena can impact tooth germ development.
- Hypovitaminosis: Deficiencies in vitamins can lead to developmental anomalies.
Associated Genetic Syndromes
Natal and neonatal teeth are often associated with several genetic syndromes, including:
- Ellis-Van Creveld Syndrome
- Riga-Fede Disease
- Pachyonychia Congenital
- Hallemann-Steriff Syndrome
- Sotos Syndrome
- Cleft Palate
Understanding these associations is crucial for comprehensive patient evaluation.
Incidence
The incidence of natal and neonatal teeth varies significantly, ranging from 1 in 6000 to 1 in 800 births. Notably:
- Approximately 90% of these teeth are normal primary teeth.
- In 85% of cases, the teeth are mandibular primary incisors.
- 5% are maxillary incisors and molars.
- The remaining 10% consist of supernumerary calcified structures.
Clinical Features
Clinically, natal and neonatal teeth may present with the following features:
- Morphologically, they can be conical or normal in size and shape.
- The color is typically opaque yellow-brownish.
- Associated symptoms may include dystrophic fingernails and hyperpigmentation.
Radiographic Evaluation
Radiographs are essential for assessing:
- The amount of root development.
- The relationship of prematurely erupted teeth to adjacent teeth.
Most prematurely erupted teeth are hypermobile due to limited root development.
Histological Characteristics
Histological examination reveals:
- Hypoplastic enamel with varying degrees of severity.
- Absence of root formation.
- Ample vascularized pulp.
- Irregular dentin formation.
- Lack of cementum formation.
These characteristics are critical for understanding the structural integrity of natal and neonatal teeth.
Harmful Effects
Natal and neonatal teeth can lead to several complications, including:
- Laceration of the lingual surface of the tongue.
- Difficulties for mothers wishing to breast-feed their infants.
Treatment Options
When considering treatment, extraction may be necessary. However, precautions must be taken:
- Avoid extractions until the 10th day of life to allow for the establishment of commensal flora in the intestine, which is essential for vitamin K production.
- If extractions are planned and the newborn has not been medicated with vitamin K immediately after birth, vitamin K supplements should be administered before the procedure to prevent hemorrhagic disease of the newborn (hypoprothrombinemia).
Apexogenesis
Apexogenesis is a vital pulp therapy procedure aimed at promoting the continued physiological development and formation of the root end of an immature tooth. This procedure is particularly relevant in pediatric dentistry, where the goal is to preserve the vitality of the dental pulp in young patients, allowing for normal root development and maturation of the tooth.
Indications for Apexogenesis
Apexogenesis is typically indicated in cases where the pulp is still vital but has been exposed due to caries, trauma, or other factors. The procedure is designed to maintain the health of the pulp tissue, thereby facilitating the ongoing development of the root structure. It is most commonly performed on immature permanent teeth, where the root has not yet fully formed.
Materials Used
Mineral Trioxide Aggregate (MTA) is frequently used in apexogenesis
procedures. MTA is a biocompatible material known for its excellent
sealing properties and ability to promote healing. It serves as a
barrier to protect the pulp and encourages the formation of a calcified barrier
at the root apex, facilitating continued root development.
Signs of Success
The most important indicator of successful apexogenesis is the
continuous completion of the root apex. This means that as the pulp
remains vital and healthy, the root continues to grow and mature, ultimately
achieving the appropriate length and thickness necessary for functional dental
health.
Contraindications
While apexogenesis can be a highly effective treatment for preserving the
vitality of the pulp in young patients, it is generally contraindicated in
children with serious systemic illnesses, such as leukemia or cancer. In these
cases, the risks associated with the procedure may outweigh the potential
benefits, and alternative treatment options may be considered.
Herpetic Gingivostomatitis
Herpetic gingivostomatitis is an infection of the oral cavity caused by the herpes simplex virus (HSV), primarily HSV type 1. It is characterized by inflammation of the gingiva and oral mucosa, and it is most commonly seen in children.
Etiology and Transmission
- Causative Agent: Herpes simplex virus (HSV).
- Transmission: The virus is communicated through
personal contact, particularly via saliva. Common routes include:
- Direct contact with an infected individual.
- Transmission from mother to child, especially during the neonatal period.
Epidemiology
- Prevalence: Studies indicate that antibodies to HSV are present in 40-90% of individuals across different populations, suggesting widespread exposure to the virus.
- Age of Onset:
- The incidence of primary herpes simplex infection increases after 6 months of age, peaking between 2 to 5 years.
- Infants under 6 months are typically protected by maternal antibodies.
Clinical Presentation
- Incubation Period: 3 to 5 days following exposure to the virus.
- Symptoms:
- General Symptoms: Fever, headache, malaise, and oral pain.
- Oral Symptoms:
- Initial presentation includes acute herpetic gingivostomatitis, with the gingiva appearing red, edematous, and inflamed.
- After 1-2 days, small vesicles develop on the oral mucosa, which subsequently rupture, leading to painful ulcers with diameters of 1-3 mm.
Course of the Disease
- Self-Limiting Nature: The primary herpes simplex infection is usually self-limiting, with recovery typically occurring within 10 days.
- Complications: In severe cases, complications may arise, necessitating hospitalization or antiviral treatment.
Treatment
- Supportive Care:
- Pain management with analgesics for fever and discomfort.
- Ensuring adequate hydration through fluid intake.
- Topical anesthetic ointments may be used to facilitate eating and reduce pain.
- Severe Cases:
- Hospitalization may be required for severe symptoms or complications.
- Antiviral agents (e.g., acyclovir) may be administered in severe cases or for immunocompromised patients.
Recurrence of Herpetic Infections
- Reactivation: Recurrent herpes simplex infections are due to the reactivation of HSV, which remains dormant in nerve tissue after the primary infection.
- Triggers for Reactivation:
- Mucosal injuries (e.g., from dental treatment).
- Environmental factors (e.g., sunlight exposure, citrus fruits).
- Location of Recurrence: Recurrent infections typically occur at the same site as the initial infection, commonly manifesting as herpes labialis (cold sores).
Dens in Dente (Tooth Within a Tooth)
Dens in dente, also known as "tooth within a tooth," is a developmental dental anomaly characterized by an invagination of the enamel and dentin, resulting in a tooth structure that resembles a tooth inside another tooth. This condition can affect both primary and permanent teeth.
Diagnosis
- Radiographic Verification:
- The diagnosis of dens in dente is confirmed through radiographic examination. Radiographs will typically show the characteristic invagination, which may appear as a radiolucent area within the tooth structure.
Characteristics
- Developmental Anomaly:
- Dens in dente is described as a lingual invagination of the enamel, which can lead to various complications, including pulp exposure, caries, and periapical pathology.
- Occurrence:
- This condition can occur in both primary and permanent teeth, although it is most commonly observed in the permanent dentition.
Commonly Affected Teeth
- Permanent Maxillary Lateral Incisors:
- Dens in dente is most frequently seen in the permanent maxillary lateral incisors. The presence of deep lingual pits in these teeth should raise suspicion for this condition.
- Unusual Cases:
- There have been reports of dens invaginatus occurring in unusual
locations, including:
- Mandibular primary canine
- Maxillary primary central incisor
- Mandibular second primary molar
- There have been reports of dens invaginatus occurring in unusual
locations, including:
Genetic Considerations
- Inheritance Pattern:
- The condition may exhibit an autosomal dominant inheritance pattern, as evidenced by the occurrence of dens in dente within the same family, where some members have the condition while others present with deep lingual pits.
- Variable Expressivity and Incomplete Penetrance:
- The variability in expression of the condition among family members suggests that it may have incomplete penetrance, meaning not all individuals with the genetic predisposition will express the phenotype.
Clinical Implications
- Management:
- Early diagnosis and management are crucial to prevent complications associated with dens in dente, such as pulpitis or abscess formation. Treatment may involve restorative procedures or endodontic therapy, depending on the severity of the invagination and the health of the pulp.