NEET MDS Lessons
Pedodontics
Moro Reflex and Startle Reflex
Moro Reflex
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The Moro reflex, also known as the startle reflex, is an involuntary response observed in infants, typically elicited by sudden movements or changes in position of the head and neck.
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Elicitation:
- A common method to elicit the Moro reflex is to pull the baby halfway to a sitting position from a supine position and then suddenly let the head fall back a short distance.
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Response:
- The reflex consists of a rapid abduction and extension of the arms, accompanied by the opening of the hands.
- Following this initial response, the arms then come together as if in an embrace.
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Clinical Importance:
- The Moro reflex provides valuable information about the infant's muscle tone and neurological function.
- An asymmetrical response may indicate:
- Unequal muscle tone on either side.
- Weakness in one arm.
- Possible injury to the humerus or clavicle.
- The Moro reflex typically disappears by 2 to 3 months of age, which is a normal part of development.
Startle Reflex
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The startle reflex is similar to the Moro reflex but is specifically triggered by sudden noises or other unexpected stimuli.
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Response:
- In the startle reflex, the elbows are flexed, and the hands remain closed, showing less of an embracing motion compared to the Moro reflex.
- The movement of the arms may involve both outward and inward motions, but it is less pronounced than in the Moro reflex.
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Clinical Importance:
- The startle reflex is an important indicator of an infant's sensory processing and neurological integrity.
- It can also be used to assess the infant's response to environmental stimuli and overall alertness.
Classification of Mouthguards
Mouthguards are essential dental appliances used primarily in sports to protect the teeth, gums, and jaw from injury. The American Society for Testing and Materials (ASTM) has established a classification system for athletic mouthguards, which categorizes them into three types based on their design, fit, and level of customization.
Classification of Mouthguards
ASTM Designation: F697-80 (Reapproved 1986)
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Type I: Stock Mouthguards
- Description: These are pre-manufactured mouthguards that come in standard sizes and shapes.
- Characteristics:
- Readily available and inexpensive.
- No customization for individual fit.
- Typically made from a single layer of material.
- May not provide optimal protection or comfort due to their generic fit.
- Usage: Suitable for recreational sports or activities where the risk of dental injury is low.
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Type II: Mouth-Formed Mouthguards
- Description: Also known as "boil-and-bite" mouthguards, these are made from thermoplastic materials that can be softened in hot water and then molded to the shape of the wearer’s teeth.
- Characteristics:
- Offers a better fit than stock mouthguards.
- Provides moderate protection and comfort.
- Can be remolded if necessary, allowing for some customization.
- Usage: Commonly used in youth sports and activities where a higher risk of dental injury exists.
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Type III: Custom-Fabricated Mouthguards
- Description: These mouthguards are custom-made by dental professionals using a dental cast of the individual’s teeth.
- Characteristics:
- Provides the best fit, comfort, and protection.
- Made from high-quality materials, often with multiple layers for enhanced shock absorption.
- Tailored to the specific dental anatomy of the wearer, ensuring optimal retention and stability.
- Usage: Recommended for athletes participating in contact sports or those at high risk for dental injuries.
Summary of Preference
- The classification system is based on an ascending order of preference:
- Type I (Stock Mouthguards): Least preferred due to lack of customization and fit.
- Type II (Mouth-Formed Mouthguards): Moderate preference, offering better fit than stock options.
- Type III (Custom-Fabricated Mouthguards): Most preferred for their superior fit, comfort, and protection.
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.
Dental stains in children can be classified into two primary categories: extrinsic stains and intrinsic stains. Each type has distinct causes and characteristics.
Extrinsic Stains
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Definition:
- These stains occur on the outer surface of the teeth and are typically caused by external factors.
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Common Causes:
- Food and Beverages: Consumption of dark-colored foods and drinks, such as berries, soda, and tea, can lead to staining.
- Bacterial Action: Certain bacteria, particularly chromogenic bacteria, can produce pigments that stain the teeth.
- Poor Oral Hygiene: Inadequate brushing and flossing can lead to plaque buildup, which can harden into tartar and cause discoloration.
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Examples:
- Green Stain: Often seen in children, particularly on the anterior teeth, caused by chromogenic bacteria and associated fungi. It appears as a dark green to light yellowish-green deposit, primarily on the labial surfaces.
- Brown and Black Stains: These can result from dietary habits, tobacco use, or iron supplements. They may appear as dark spots or lines on the teeth.
Intrinsic Stains
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Definition:
- These stains originate from within the tooth structure and are often more difficult to treat.
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Common Causes:
- Medications: Certain antibiotics, such as tetracycline, can cause grayish-brown discoloration if taken during tooth development.
- Fluorosis: Excessive fluoride exposure during enamel formation can lead to white spots or brown streaks on the teeth.
- Genetic Factors: Conditions affecting enamel development can result in intrinsic staining.
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Examples:
- Yellow or Gray Stains: Often linked to genetic factors or developmental issues, these stains can be more challenging to remove and may require professional intervention.
Management and Prevention
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Regular Dental Check-ups:
- Schedule routine visits to the dentist for early detection and management of stains.
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Good Oral Hygiene Practices:
- Encourage children to brush twice a day and floss daily to prevent plaque buildup and staining.
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Dietary Considerations:
- Limit the intake of sugary and acidic foods and beverages that can contribute to staining.
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).
Cherubism
Cherubism is a rare genetic disorder characterized by bilateral or asymmetric enlargement of the jaws, primarily affecting children. It is classified as a benign fibro-osseous condition and is often associated with distinctive radiographic and histological features.
Clinical Presentation
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Jaw Enlargement:
- Patients may present with symmetric or asymmetric enlargement of the mandible and/or maxilla, often noticeable at an early age.
- The enlargement can lead to facial deformities and may affect the child's appearance and dental alignment.
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Tooth Eruption and Loss:
- Teeth in the affected areas may exfoliate prematurely due to loss of support, root resorption, or interference with root development in permanent teeth.
- Spontaneous loss of teeth can occur, or children may extract teeth themselves from the soft tissue.
Radiographic Features
- Bone Destruction:
- Radiographs typically reveal numerous sharp, well-defined multilocular areas of bone destruction.
- There is often thinning of the cortical plate surrounding the affected areas.
- Cystic Involvement:
- The radiographic appearance is often described as "soap bubble" or "honeycomb" due to the multilocular nature of the lesions.
Case Report
- Example: McDonald and Shafer reported a case involving
a 5-year-old girl with symmetric enlargement of both the mandible and
maxilla.
- Radiographic Findings: Multilocular cystic involvement was observed in both the mandible and maxilla.
- Skeletal Survey: A complete skeletal survey did not reveal similar lesions in other bones, indicating the localized nature of cherubism.
Histological Features
- Microscopic Examination:
- A biopsy of the affected bone typically shows a large number of multinucleated giant cells scattered throughout a cellular stroma.
- The giant cells are large, irregularly shaped, and contain 30-40 nuclei, which is characteristic of cherubism.
Pathophysiology
- Genetic Basis: Cherubism is believed to have a genetic component, often inherited in an autosomal dominant pattern. Mutations in the SH3BP2 gene have been implicated in the condition.
- Bone Remodeling: The presence of giant cells suggests an active process of bone remodeling and resorption, contributing to the characteristic bone changes seen in cherubism.
Management
- Monitoring: Regular follow-up and monitoring of the condition are essential, especially during periods of growth.
- Surgical Intervention: In cases where the enlargement causes significant functional or aesthetic concerns, surgical intervention may be considered to remove the affected bone and restore normal contour.
- Dental Care: Management of dental issues, including premature tooth loss and alignment problems, is crucial for maintaining oral health.
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.