Cerebral palsy is a group of permanent disorders of movement and posture causing activity limitations, attributed to non-progressive disturbances in the developing fetal or infant brain.

Classification by Motor Type

A. Spastic Cerebral Palsy (70-80%)

Characteristics:

• Increased muscle tone (hypertonia)
• Exaggerated reflexes
• Muscle stiffness
• Contractures

Subtypes:

1. Spastic Hemiplegia - One side affected
2. Spastic Diplegia - Lower limbs more affected
3. Spastic Quadriplegia - All four limbs affected

B. Dyskinetic Cerebral Palsy (10-20%)

Key Types

1. Athetosis

   • Slow, writhing movements
   • Involuntary, continuous
   • Affects distal muscles more
   • Worsens with stress/excitement

2. Choreoathetosis

   • Combination of choreic and athetoid movements
   • Choreic: Quick, jerky, irregular movements
   • Athetoid: Slow, writhing movements
   • Most common dyskinetic type

3. Dystonia

   • Sustained muscle contractions
   • Repetitive twisting movements
   • Abnormal postures

C. Ataxic Cerebral Palsy (5-10%)

Characteristics:

• Poor balance and coordination
• Unsteady gait
• Intention tremor
• Speech difficulties

Dental Implications of Cerebral Palsy

• Oral hygiene: Difficulty in maintaining
• Feeding problems: Swallowing difficulties, drooling
• Dental anomalies: Delayed eruption, enamel defects
• Malocclusion: High prevalence
• Trauma risk: Due to falls and poor coordination
• Medication effects: Gingival hyperplasia (anticonvulsants)

Timeline Facts:

1. Root completion primary teeth: 3-4 years
2. Delayed deciduous eruption: Dentitia tarda
3. Peak mixed dentition: 8.5 years (12+12 teeth)
4. Smallest primary tooth: Mandibular central incisor

Morphology Resemblances:

1. Primary max 2nd molar ≈ Permanent max 1st molar
2. Primary mand 1st molar ≈ Permanent mand 1st molar

Development Stages:

1. Crown initiation: 14-19 weeks IU
2. First eruption: Lower central incisors (6-8 months)
3. Last primary eruption: Second molars (24-30 months)

Common Question Patterns:

• "When do primary tooth roots complete?" → 3-4 years
• "What is delayed deciduous eruption called?" → Dentitia tarda
• "Smallest primary tooth?" → Mandibular central incisor
• "Primary tooth resembling permanent first molar?" → Primary maxillary second molar
• "12 primary + 12 permanent teeth age?" → 8.5 years

Memory Aids:

• Root completion: "3-4 years for Primary Roots"
• Dentitia tarda: "Tardy Teeth = Late Eruption"
• Smallest primary: "Lower Central = Littlest & Cutest"
• Resemblances: "Max 2nd = Max 1st", "Mand 1st = Mand 1st"
• Mixed dentition peak: "8.5 = 12+12 = Peak Mix"

Clinical Correlations:

• 3-4 year root completion → Pulp therapy considerations
• Dentitia tarda → Systemic evaluation needed
• Smallest primary tooth → Easiest extraction, first mobility
• Molar resemblances → Space analysis predictability
• 8.5 year mixed dentition → Orthodontic intervention timing

Paralleling Technique in Dental Radiography

Overview of the Paralleling Technique

The paralleling technique is a method used in dental radiography to obtain accurate and high-quality images of teeth. This technique ensures that the film and the long axis of the tooth are parallel, which is essential for minimizing distortion and maximizing image clarity.

Principles of the Paralleling Technique

1. Parallel Alignment:

   • The fundamental principle of the paralleling technique is to maintain parallelism between the film (or sensor) and the long axis of the tooth in all dimensions. This alignment is crucial for accurate imaging.

2. Film Placement:

   • To achieve parallelism, the film packet is positioned farther away from the object, particularly in the maxillary region. This distance can lead to image magnification, which is an undesirable effect.

3. Use of a Longer Cone:

   • To counteract the magnification caused by increased film distance, a longer cone (position-indicating device or PID) is employed. The longer cone helps:
     • Reduce Magnification: By increasing the distance from the source of radiation to the film, the image size is minimized.
     • Enhance Image Sharpness: A longer cone decreases the penumbra (the blurred edge of the image), resulting in sharper images.

4. True Parallelism:

   • Striving for true parallelism enhances image accuracy, allowing for better diagnostic quality.

Film Holder and Beam-Aligning Devices

• Film Holder:
  • A film holder is necessary when using the paralleling technique, as it helps maintain the correct position of the film relative to the tooth.
  • Some film holders are equipped with beam-aligning devices that assist in ensuring parallelism and reducing partial exposure of the film, thereby eliminating unwanted cone cuts.

Considerations for Pediatric Patients

• Size Adjustment:

  • For smaller children, the film holder may need to be reduced in size to accommodate both the film and the child’s mouth comfortably.

• Operator Error Reduction:

  • Proper use of film holders and beam-aligning devices can help minimize operator error and reduce the patient's exposure to radiation.

• Challenges with Film Placement:

  • Due to the shallowness of a child's palate and floor of the mouth, film placement can be somewhat compromised. However, with careful technique, satisfactory films can still be obtained.

• Plasma peak of fluoride: 180 min
• Fluoride in breast milk: 5 – 10 mg/L
• Earth’s crust fluoride: ~300 ppm
• Dry tea leaf fluoride: 100 – 400 ppm
• Renal clearance: 30 – 50 mL/min
• Plasma fluoride level: 19 – 38 ng/mL
• Plaque fluoride concentration: 15 – 64 ppm
• Sweat fluoride concentration: 0.067 – 0.05 ppm
• Reliable fluoride analysis method: Microdiffusion (Taves, 1983)
• Fluoride in pea-sized toothpaste: 250 mg
• Non-caloric sweeteners: Saccharin, Aspartame

Most Accepted Caries Detection Method: Bitewing Radiograph

Gold Standard Status:

• Most accepted method for interproximal caries detection
• High sensitivity and specificity for approximal surfaces
• Widely used in general practice
• Cost-effective diagnostic tool

Advantages of Bitewing Radiographs:

1. Interproximal caries detection: Unmatched accuracy
2. Bone level assessment: Periodontal evaluation
3. Restoration integrity: Secondary caries detection
4. Comparative analysis: Serial monitoring possible
5. Documentation: Legal and clinical records

Bitewing Film Size (Deciduous Teeth): Size 0 🎯

Intraoral Film Sizes:

• Size 0: 18 × 24 mm - Deciduous teeth, small mouths
• Size 1: 24 × 40 mm - Anterior teeth, small adults
• Size 2: 31 × 41 mm - Adult posterior (most common)
• Size 3: 27 × 54 mm - Long bitewing
• Size 4: 57 × 76 mm - Occlusal films

Size 0 Specifications:

• Dimensions: 18 × 24 mm
• Primary use: Deciduous dentition
• Age group: 3-8 years typically
• Coverage: Posterior primary teeth
• Technique: Modified bitewing approach

CLINICAL SIGNIFICANCE: Size 0 films accommodate small mouths and provide adequate coverage of primary posterior teeth.

Caries Detection in General Practice: Bitewing Radiograph

Practice Integration:

• Routine screening: Part of comprehensive examination
• Insurance acceptance: Widely covered diagnostic procedure
• Evidence-based: Strong research support
• Cost-effectiveness: High diagnostic yield per cost

Recommended Frequency:

• High caries risk: Every 6 months
• Moderate caries risk: Every 12 months
• Low caries risk: Every 18-24 months