Phenytoin-Induced Gingival Overgrowth

• Phenytoin (Dilantin):
  • An anticonvulsant medication primarily used in the treatment of epilepsy.
  • First introduced in 1938 by Merrit and Putnam.

Gingival Hyperplasia

• Gingival hyperplasia refers to the overgrowth of gum tissue, which can lead to aesthetic concerns and functional issues, such as difficulty in maintaining oral hygiene.
• Historical Context:
  • The association between phenytoin therapy and gingival hyperplasia was first reported by Kimball in 1939.
  • In his study, 57% of 119 patients taking phenytoin for seizure control experienced some degree of gingival overgrowth.

Mechanism of Gingival Overgrowth

• Fibroblast Activity:

  • Early research indicated an increase in the number of fibroblasts in the gingival tissues of patients receiving phenytoin.
  • This led to the initial terminology of "Dilantin hyperplasia."

• Current Understanding:

  • Subsequent studies, including those by Hassell and colleagues, have shown that true hyperplasia does not exist in this condition.
  • Findings indicate:
    • There is no excessive collagen accumulation per unit of tissue.
    • Fibroblasts do not appear abnormal in number or size.
  • As a result, the term phenytoin-induced gingival overgrowth is now preferred, as it more accurately reflects the condition.

Clinical Implications

• Management:

  • Patients on phenytoin should be monitored for signs of gingival overgrowth, especially if they have poor oral hygiene or other risk factors.
  • Dental professionals should educate patients about maintaining good oral hygiene practices to minimize the risk of gingival overgrowth.
  • In cases of significant overgrowth, treatment options may include:
    • Improved oral hygiene measures.
    • Professional dental cleanings.
    • Surgical intervention (gingivectomy) if necessary.

• Patient Education:

  • It is important to inform patients about the potential side effects of phenytoin, including gingival overgrowth, and the importance of regular dental check-ups.

Classification of Oral Habits

Oral habits can be classified based on various criteria, including their nature, impact, and the underlying motivations for the behavior. Below is a detailed classification of oral habits:

1. Based on Nature of the Habit

• Obsessive Habits (Deep Rooted):

  • International or Meaningful:
    • Examples: Nail biting, digit sucking, lip biting.
  • Masochistic (Self-Inflicting):
    • Examples: Gingival stripping (damaging the gums).
  • Unintentional (Empty):
    • Examples: Abnormal pillowing, chin propping.

• Non-Obsessive Habits (Easily Learned and Dropped):

  • Functional Habits:
    • Examples: Mouth breathing, tongue thrusting, bruxism (teeth grinding).

2. Based on Impact

• Useful Habits:
  • Habits that may have a positive or neutral effect on oral health.
• Harmful Habits:
  • Habits that can lead to dental issues, such as malocclusion, gingival damage, or tooth wear.

3. Based on Author Classifications

• James (1923):

  • a) Useful Habits
  • b) Harmful Habits

• Kingsley (1958):

  • a) Functional Oral Habits
  • b) Muscular Habits
  • c) Combined Habits

• Morris and Bohanna (1969):

  • a) Pressure Habits
  • b) Non-Pressure Habits
  • c) Biting Habits

• Klein (1971):

  • a) Empty Habits
  • b) Meaningful Habits

• Finn (1987):

  • I. a) Compulsive Habits
  • b) Non-Compulsive Habits
  • II. a) Primary Habits

4. Based on Functionality

• Functional Habits:
  • Habits that serve a purpose, such as aiding in speech or feeding.
• Dysfunctional Habits:
  • Habits that disrupt normal oral function or lead to negative consequences.

Agents Used for Sedation in Children

1. 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.

2. Benzodiazepines

   • Examples:
     • Diazepam: Used for its anxiolytic and sedative properties.
     • Midazolam: Frequently utilized for its rapid onset and short duration of action.

3. Barbiturates

   • Description: Sedative-hypnotics that can be used for sedation, though less commonly in modern practice due to the availability of safer alternatives.

4. Chloral Hydrate

   • Description: A sedative-hypnotic agent used for its calming effects in children.

5. Narcotics

   • Examples:
     • Meperidine: Provides analgesia and sedation.
     • Fentanyl: A potent opioid used for sedation and pain management.

6. 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.

7. 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.

Tooth Replantation and Avulsion Injuries

Tooth avulsion is a dental emergency that occurs when a tooth is completely displaced from its socket. The success of replantation, which involves placing the avulsed tooth back into its socket, is influenced by several factors, including the time elapsed since the avulsion and the condition of the periodontal ligament (PDL) tissue.

Key Factors Influencing Replantation Success

1. Time Elapsed Since Avulsion:

   • The length of time between the loss of the tooth and its replantation is critical. The sooner a tooth can be replanted, the better the prognosis for retention and vitality.
   • Prognosis Statistics:
     • Replantation within 30 minutes: Approximately 90% of replanted teeth show no evidence of root resorption after 2 or more years.
     • Replantation after 2 hours: About 95% of these teeth exhibit root resorption.

2. Condition of the Tooth:

   • The condition of the tooth at the time of replantation, particularly the health of the periodontal ligament tissue remaining on the root surface, significantly affects the outcome.
   • Immediate replacement of a permanent tooth can sometimes lead to vitality and indefinite retention, but this is not guaranteed.

3. Temporary Measure:

   • While replantation can be successful, it should generally be viewed as a temporary solution. Many replanted teeth may be retained for 5 to 10 years, with a few lasting a lifetime, but others may fail shortly after replantation.

Common Avulsion Injuries

• Most Commonly Avulsed Tooth: The maxillary central incisor is the tooth most frequently avulsed in both primary and permanent dentition.
• Demographics:
  • Avulsion injuries typically involve a single tooth and are three times more common in boys than in girls.
  • The highest incidence occurs in children aged 7 to 9 years, coinciding with the eruption of permanent incisors.
• Structural Factors: The loosely structured periodontal ligament surrounding erupting teeth may predispose them to complete avulsion.

Recommendations for Management of Avulsed Teeth

1. Immediate Action: If a tooth is avulsed, it should be replanted as soon as possible. If immediate replantation is not feasible, the tooth should be kept moist.

   • Storage Options: The tooth can be stored in:
     • Cold milk (preferably whole milk)
     • Saline solution
     • Patient's own saliva (by placing it in the buccal vestibule)
     • A sterile saline solution
   • Avoid: Storing the tooth in water, as this can damage the periodontal ligament cells.

2. Professional Care: Seek dental care immediately after an avulsion injury to ensure proper replantation and follow-up care.

1. Crown Dimensions

• 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.

• 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

• 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.

• 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

• 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.

• 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

• 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.

• 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.

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:

• 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.

• 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.

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:

• 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.

• 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:

• 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.

• 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.