NEET MDS Lessons
Pedodontics
Photostimulable Phosphors (PSPs) in Digital Imaging
- Photostimulable phosphors (PSPs), also known as storage phosphors, are materials used in digital imaging for the acquisition of radiographic images. They serve as an alternative to traditional film-based radiography.
Characteristics of PSPs
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Storage Mechanism: Unlike conventional screen materials used in panoramic or cephalometric imaging, PSPs do not fluoresce immediately upon exposure to x-ray photons. Instead, they capture and store the incoming x-ray photon information as a latent image.
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Latent Image: The latent image is similar to that found in traditional film radiography, where the image is not visible until processed.
Image Acquisition Process
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Exposure:
- The PSP plate is exposed to x-rays, which causes the phosphor material to absorb and store the energy from the x-ray photons.
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Scanning:
- After exposure, the PSP plate is scanned by a laser beam in a drum scanner. This process is crucial for retrieving the stored image information.
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Energy Release:
- The laser scanning excites the phosphor, causing it to release the stored energy as an electronic signal. This signal represents the latent image captured during the x-ray exposure.
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Digitalization:
- The electronic signal is then digitized, with various gray levels assigned to different points on the curve. This process creates the final image information that can be viewed and analyzed.
Advantages of PSP Systems
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Image Quality: PSPs can produce high-quality images with a wide dynamic range, allowing for better visualization of anatomical structures.
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Reusability: PSP plates can be reused multiple times, making them a cost-effective option for dental practices.
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Compatibility: PSP systems can be integrated into existing digital imaging workflows, providing flexibility for dental professionals.
Available PSP Imaging Systems
- Soredex: OpTime
- AirTechniques: Scan X
- Gendex: Denoptix
These systems offer various features and capabilities, allowing dental practices to choose the best option for their imaging needs.
Soldered Lingual Holding Arch as a Space Maintainer
Introduction
The soldered lingual holding arch is a classic bilateral mixed-dentition space maintainer used in the mandibular arch. It is designed to preserve the space for the permanent canines and premolars during the mixed dentition phase, particularly when primary molars are lost prematurely.
Design and Construction
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Components:
- Bands: Fitted to the first permanent molars.
- Wire: A 0.036- or 0.040-inch stainless steel wire is contoured to the arch.
- Extension: The wire extends forward to make contact with the cingulum area of the incisors.
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Arch Form: The wire is contoured to provide an anterior arch form, allowing for the alignment of the incisors while ensuring it does not interfere with the normal eruption paths of the teeth.
Functionality
- Stabilization: The design stabilizes the positions of the lower molars, preventing them from moving mesially and maintaining the incisor relationship to avoid retroclination.
- Leeway Space: The arch helps sustain the canine-premolar segment space, utilizing the leeway space available during the mixed dentition phase.
Clinical Considerations
- Eruption Path: The lingual wire must be contoured to avoid interference with the normal eruption paths of the permanent canines and premolars.
- Breakage and Hygiene: The soldered lingual holding arch is designed to present minimal problems with breakage and minimal oral hygiene concerns.
- Eruptive Movements: It should not interfere with the eruptive movements of the permanent teeth, allowing for natural development.
Timing of Placement
- Transitional Dentition Period: The bilateral design and use of permanent teeth as abutments allow for application during the full transitional dentition period of the buccal segments.
- Timing of Insertion: Lower lingual arches should not be placed before the eruption of the permanent incisors due to their frequent lingual eruption path. If placed too early, the lingual wire may interfere with normal incisor positioning, particularly before the lateral incisor erupts.
- Anchorage: Using primary incisors as anterior stops does not provide sufficient anchorage to prevent significant loss of arch length.
Wright's Classification of Child Behavior
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Hysterical/Uncontrolled
- Description: This behavior is often seen in preschool children during their first dental visit. These children may exhibit temper tantrums, crying, and an inability to control their emotions. Their reactions can be intense and overwhelming, making it challenging for dental professionals to proceed with treatment.
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Defiant/Obstinate
- Description: Children displaying defiant behavior may refuse to cooperate or follow instructions. They may argue or resist the dental team's efforts, making it difficult to conduct examinations or procedures.
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Timid/Shy
- Description: Timid or shy children may be hesitant to engage with the dental team. They might avoid eye contact, speak softly, or cling to their parents. This behavior can stem from anxiety or fear of the unfamiliar dental environment.
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Stoic
- Description: Stoic children may not outwardly express their feelings, even in uncomfortable situations. This behavior can be seen in spoiled or stubborn children, where their crying may be characterized by a "siren-like" quality. They may appear calm but are internally distressed.
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Overprotective Child
- Description: These children may exhibit clinginess or anxiety, often due to overprotective parenting. They may be overly reliant on their parents for comfort and reassurance, which can complicate the dental visit.
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Physically Abused Child
- Description: Children who have experienced physical abuse may display heightened anxiety, fear, or aggression in the dental setting. Their behavior may be unpredictable, and they may react strongly to perceived threats.
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Whining Type
- Description: Whining children may express discomfort or displeasure through persistent complaints or whining. This behavior can be a way to seek attention or express anxiety about the dental visit.
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Complaining Type
- Description: Similar to whining, complaining children vocalize their discomfort or dissatisfaction. They may frequently express concerns about the procedure or the dental environment.
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Tense Cooperative
- Description: These children are on the borderline between positive and negative behavior. They may show some willingness to cooperate but are visibly tense or anxious. Their cooperation may be conditional, and they may require additional reassurance and support.
Agents Used for Sedation in Children
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Nitrous Oxide (N₂O)
- Type: Gaseous agent
- Description: Commonly used for conscious sedation in pediatric dentistry. It provides anxiolytic and analgesic effects, making dental procedures more tolerable for children.
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Benzodiazepines
- Examples:
- Diazepam: Used for its anxiolytic and sedative properties.
- Midazolam: Frequently utilized for its rapid onset and short duration of action.
- Examples:
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Barbiturates
- Description: Sedative-hypnotics that can be used for sedation, though less commonly in modern practice due to the availability of safer alternatives.
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Chloral Hydrate
- Description: A sedative-hypnotic agent used for its calming effects in children.
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Narcotics
- Examples:
- Meperidine: Provides analgesia and sedation.
- Fentanyl: A potent opioid used for sedation and pain management.
- Examples:
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Antihistamines
- Examples:
- Hydroxyzine: An anxiolytic and sedative.
- Promethazine (Phenergan): Used for sedation and antiemetic effects.
- Chlorpromazine: An antipsychotic that can also provide sedation.
- Diphenhydramine: An antihistamine with sedative properties.
- Examples:
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Dissociative Agents
- Example:
- Ketamine: Provides dissociative anesthesia, analgesia, and sedation. It is particularly useful in emergency settings and for procedures that may cause significant discomfort.
- Example:
Endodontic Filling Techniques
Endodontic filling techniques are essential for the successful treatment of root canal systems. Various methods have been developed to ensure that the canal is adequately filled with the appropriate material, providing a seal to prevent reinfection.
1. Endodontic Pressure Syringe
- Developed By: Greenberg; technique described by Speeding and Karakow in 1965.
- Features:
- Consists of a syringe barrel, threaded plunger, wrench, and threaded needle.
- The needle is placed 1 mm short of the apex.
- The technique involves a slow withdrawing motion, where the needle is withdrawn 3 mm with each quarter turn of the screw until the canal is visibly filled at the orifice.
2. Mechanical Syringe
- Proposed By: Greenberg in 1971.
- Features:
- Cement is loaded into the syringe using a 30-gauge needle, following the manufacturer's recommendations.
- The cement is expressed into the canal while applying continuous pressure and withdrawing the needle simultaneously.
3. Tuberculin Syringe
- Utilized By: Aylord and Johnson in 1987.
- Features:
- A standard 26-gauge, 3/8 inch needle is used for this technique.
- This method allows for precise delivery of filling material into the canal.
4. Jiffy Tubes
- Popularized By: Riffcin in 1980.
- Features:
- Material is expressed into the canal using slow finger pressure on the plunger until the canal is visibly filled at the orifice.
- This technique provides a simple and effective way to fill the canal.
5. Incremental Filling
- First Used By: Gould in 1972.
- Features:
- An endodontic plugger, corresponding to the size of the canal with a rubber stop, is used to place a thick mix of cement into the canal.
- The thick mix is prepared into a flame shape that corresponds to the size and shape of the canal and is gently tapped into the apical area with the plugger.
6. Lentulospiral Technique
- Advocated By: Kopel in 1970.
- Features:
- A lentulospiral is dipped into the filling material and introduced into the canal to its predetermined length.
- The lentulospiral is rotated within the canal, and additional paste is added until the canal is filled.
7. Other Techniques
- Amalgam Plugger:
- Introduced by Nosonwitz (1960) and King (1984) for filling canals.
- Paper Points:
- Utilized by Spedding (1973) for drying and filling canals.
- Plugging Action with Wet Cotton Pellet:
- Proposed by Donnenberg (1974) as a method to aid in the filling process.
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.
Recurrent Aphthous Ulcers (Canker Sores)
Overview of Recurrent Aphthous Ulcers (RAU)
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Definition:
- Recurrent aphthous ulcers, commonly known as canker sores, are painful ulcerations that occur on the unattached mucous membranes of the mouth. They are characterized by their recurrent nature and can significantly impact the quality of life for affected individuals.
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Demographics:
- RAU is most prevalent in school-aged children and young adults, with a peak incidence between the ages of 10 and 19 years.
- It is reported to be the most common mucosal disorder across various ages and races globally.
Clinical Features
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Characteristics:
- RAU is defined by recurrent ulcerations on the moist mucous membranes of the mouth.
- Lesions can be discrete or confluent, forming rapidly in certain areas.
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They typically feature:
- A round to oval crateriform base.
- Raised, reddened margins.
- Significant pain.
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Types of Lesions:
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Minor Aphthous Ulcers:
- Usually single, smaller lesions that heal without scarring.
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Major Aphthous Ulcers (RAS):
- Larger, more painful lesions that may take longer to heal and can leave scars.
- Also referred to as periadenitis mucosa necrotica recurrens or Sutton disease.
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Herpetiform Ulcers:
- Multiple small lesions that can appear in clusters.
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Minor Aphthous Ulcers:
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Duration and Healing:
- Lesions typically persist for 4 to 12 days and heal uneventfully, with scarring occurring only rarely and usually in cases of unusually large lesions.
Epidemiology
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Prevalence:
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The condition occurs approximately three times more frequently in white
children compared to black children.
- Prevalence estimates of RAU range from 2% to 50%, with most estimates falling between 5% and 25%. Among medical and dental students, the estimated prevalence is between 50% and 60%.
Associated Conditions
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Systemic Associations:
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RAS has been linked to several systemic diseases, including:
- PFAPA Syndrome: Periodic fever, aphthous stomatitis, pharyngitis, and adenitis.
- Behçet Disease: A systemic condition characterized by recurrent oral and genital ulcers.
- Crohn's Disease: An inflammatory bowel disease that can present with oral manifestations.
- Ulcerative Colitis: Another form of inflammatory bowel disease.
- Celiac Disease: An autoimmune disorder triggered by gluten.
- Neutropenia: A condition characterized by low levels of neutrophils, leading to increased susceptibility to infections.
- Immunodeficiency Syndromes: Conditions that impair the immune system.
- Reiter Syndrome: A type of reactive arthritis that can present with oral ulcers.
- Systemic Lupus Erythematosus: An autoimmune disease that can cause various oral lesions.
- MAGIC Syndrome: Mouth and genital ulcers with inflamed cartilage.
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RAS has been linked to several systemic diseases, including: