NEET MDS Lessons
Periodontology
- Bone Defects:
- Most common: Osseous craters.
- Best graft success: Three-walled defects.
- Bone graft types:
- Autogenous cancellous: Most osteogenic.
- Xenograft: From different species.
- Osteoplasty: Recontouring without removing supporting bone.
- Osteotomy: Removes supporting bone.
- Implants:
- Minimum 5 mm from mental foramen.
- Blade implants: Linkow; Cylindrical: Schroeder.
- Micro-movement >150 µm: Fibrous tissue formation.
- Connective tissue near implant: No blood vessels, many fibroblasts.
- Probing: Use plastic probes; max force = 25 N.
- Florida probe tip: 0.4 mm.
Flossing Technique
Flossing is an essential part of oral hygiene that helps remove plaque and food particles from between the teeth and along the gumline, areas that toothbrushes may not effectively clean. Proper flossing technique is crucial for maintaining gum health and preventing cavities.
Flossing Technique
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Preparation:
- Length of Floss: Take 12 to 18 inches of dental floss. This length allows for adequate maneuverability and ensures that you can use a clean section of floss for each tooth.
- Grasping the Floss: Hold the floss taut between your hands, leaving a couple of inches of floss between your fingers. This tension helps control the floss as you maneuver it between your teeth.
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Inserting the Floss:
- Slip Between Teeth: Gently slide the floss between your teeth. Be careful not to snap the floss, as this can cause trauma to the gums.
- Positioning: Insert the floss into the area between your teeth and gums as far as it will comfortably go, ensuring that you reach the gumline.
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Flossing Motion:
- Vertical Strokes: Use 8 to 10 vertical strokes with the floss to dislodge food particles and plaque. Move the floss up and down against the sides of each tooth, making sure to clean both the front and back surfaces.
- C-Shaped Motion: For optimal cleaning, wrap the floss around the tooth in a C-shape and gently slide it beneath the gumline.
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Frequency:
- Daily Flossing: Aim to floss at least once a day. Consistency is key to maintaining good oral hygiene.
- Best Time to Floss: The most important time to floss is before going to bed, as this helps remove debris and plaque that can accumulate throughout the day.
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Flossing and Brushing:
- Order of Operations: Flossing can be done either before or after brushing your teeth. Both methods are effective, so choose the one that fits best into your routine.
ANUG (Acute Necrotizing Ulcerative Gingivitis)
- Signs: Punched – out crater depressions of interdental papilla
- Symptoms: Metallic foul taste, pasty saliva
- Treatment: 3 visits (2nd visit: 1 – 2 days after 1st; 3rd visit: 5 days after 2nd)
NUG/NUP
- No pocket formation (destroys junctional epithelium)
Primary Herpetic Gingivostomatitis
- Cellular change: Ballooning degeneration → Tzanck cells
- Treatment:
- Within 3 days: Acyclovir 15 mg/kg × 5 times × 7 days
- After 3 days: Supportive care with NSAIDs
Leukemic Gingivitis
- Most common in acute monocytic leukemia
Lead Intoxication
- Steel gray linear pigmentation (Burton's line)
Assessing New Attachment in Periodontal Therapy
Assessing new attachment following periodontal therapy is crucial for evaluating treatment outcomes and understanding the healing process. However, various methods of assessment have limitations that must be considered.
1. Periodontal Probing
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Assessment Method: Periodontal probing is commonly used to measure probing depth and attachment levels before and after therapy.
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Limitations:
- Coronal Positioning of Probe Tip: After therapy, when the inflammatory lesion is resolved, the probe tip may stop coronal to the apical termination of the epithelium. This can lead to misleading interpretations of attachment gain.
- Infrabony Defects: Following treatment of infrabony defects, new bone may form so close to the tooth surface that the probe cannot penetrate. This can result in a false impression of improved attachment levels.
- Interpretation of Results: A gain in probing attachment level does not necessarily indicate a true gain of connective tissue attachment. Instead, it may reflect improved health of the surrounding tissues, which increases resistance to probe penetration.
2. Radiographic Analysis and Reentry Operations
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Assessment Method: Radiographic analysis involves comparing radiographs taken before and after therapy to evaluate changes in bone levels. Reentry operations allow for direct inspection of the treated area.
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Limitations:
- Bone Fill vs. New Attachment: While radiographs can provide evidence of new bone formation (bone fill), they do not document the formation of new root cementum or a new periodontal ligament. Therefore, radiographic evidence alone cannot confirm the establishment of new attachment.
3. Histologic Methods
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Assessment Method: Histologic analysis involves examining tissue samples under a microscope to assess the formation of new attachment, including new cementum and periodontal ligament.
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Advantages:
- Validity: Histologic methods are considered the only valid approach to assess the formation of new attachment accurately.
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Limitations:
- Pre-Therapy Assessment: Accurate assessment of the attachment level prior to therapy is essential for histologic analysis. If the initial attachment level cannot be determined with certainty, it may compromise the validity of the findings.
Plaque Formation
- Initial colonizers: Gram – positive bacteria
- Mature plaque: Shift to obligate anaerobes, proteolytic, rods, motile
- Plaque weight: 2×10¹¹ bacteria per gram
Bacterial Complexes
- Red Complex (Most pathogenic): P. gingivalis, T. denticola, B. forsythia
- Green Complex: A. actinomycetemcomitans, E. corrodens, Capnocytophaga
- BANA Test: Detects trypsin – like enzyme in T. denticola, P. gingivalis, B. forsythia
Specific Bacteria
- A. actinomycetemcomitans: Invades host cells, secretes leukotoxin (116 – kDa protein)
- P. intermedia: Increases with steroid hormones (pregnancy/puberty)
- S. oralis: Found in treated gingival sulcus
- S. sanguis: First organism on oral mucosa
🫁 Respiratory Physiology & Pathology
| Concept | Key Insight |
|---|---|
| Mean Arterial Pressure | Diastolic + 1/3 pulse pressure |
| Pulse Pressure | Systolic – Diastolic |
| Hemoptysis source | Most commonly bronchial artery |
| Cavitary TB lesion | Highly infective, absent in HIV-associated TB |
| Miliary TB | Mantoux negative |
| Recurrent hemoptysis | Often due to TB reactivation or vascular erosion |
Types & Composition
- Supragingival: White/whitish – yellow, mineral source = saliva
- Subgingival: Dark brown/greenish – black, mineral source = GCF
Crystal Composition
- Hydroxyapatite: 58%
- Magnesium whitelockite: 21%
- Octacalcium phosphate: 12%
- Brushite: 8%