Periodontal Radiography, Bone Defects, and Mechanical Plaque Control

The Importance and Role of Radiography in Periodontics

• Dental Baseline: Radiographs are essential in dentistry and periodontics specifically because they establish a clinical baseline for the patient.
• Permanent Documentation: They serve as permanent records of the patient's oral health on a specific day.
• Digital vs. Film: Most modern practices utilize digital radiographs. However, students should be aware that some practices may still use traditional film, though it is increasingly rare.
• Diagnostic Power: Radiographs provide data on:
  • Number of teeth present.
  • Interdental bone level (indicates the amount of bone support).
  • Clinical crown-to-root ratio.
  • Periodontal ligament (PDL) condition.
  • Interproximal health and restoration contours (detecting overhangs).
  • Radiographic calculus (often more significant than it appears on the film).
  • Tooth morphology (e.g., long vs. short roots, tipped teeth).
• Identification Use Case: A real-world application of dental records includes forensic identification. The lecturer recounted a case where the coroner\'s office used a patient's radiographs to identify them after they passed away alone.

Panorex (Panoramic) vs. Diagnostic Intraoral Radiographs

• Limitations in Periodontics: It is vital for dental professionals not to rely on a Panorex (panoramic film) for treating periodontal disease. The Panorex produces a distorted image that lacks the clear, cut view necessary to assess bone support accurately.
• Appropriate Uses for Panorex:
  • Viewing broad anatomical structures.
  • Visualizing the sinuses and nerves.
  • Identifying general pathology.
  • Initial steps and planning for dental implants.
• Diagnostic Integrity: When taking radiographs (Bitewings or Periapicals), they must be diagnostic. This means avoiding "cone cuts" and ensuring the entire structure of the tooth is visible.

Normal Radiographic Anatomy and Early Signs of Disease

• Normal Bone Height: In a healthy state with no bone loss, the crestal bone is approximately $2\,mm$ from the Cementoenamel Junction (CEJ).
• Crestal Lamina Dura: This is the bone lining the tooth socket. On a radiograph, it appears as a white line (though it is biologically penetrated by nerves and blood vessels). Its appearance helps determine the stability of the bone and the level of bone loss.
• The "Rookie Mistake" (Over-diagnosis): Beginners often misdiagnose angular bone loss when viewing tipped teeth. The bone naturally follows the CEJ; if the tooth is tilted, the bone line will tilt with it. If the bone parallels the CEJ, there is no radiographic bone loss.
• Localized Aggressive Patterns: In young patients, clinicians should look for "localized severe" periodontitis, which often presents in a specific "molar-incisor pattern."

Classifying Bone Defects and Furcation Involvement

• Bone Loss Patterns:
  • Horizontal Bone Loss: The bone level is reduced but remains relatively even and perpendicular to the tooth.
  • Vertical/Angular Bone Loss: The bone loss is uneven and not horizontal.
• Intrabony Defects (Wall Classification): Defects are classified by the number of remaining osseous walls. The tooth is never counted as a wall.
  • One-wall Defect (Hemiseptal): Bone is high on one tooth and low on the adjacent tooth, resembling a "ski slope." These are plaque-retentive and difficult to clean.
  • Two-wall Defect (Crater): The most common interproximal defect. It occurs when buccal and lingual walls remain, but the bone between them is "scooped out." Commonly caused by inconsistent flossing.
  • Three-wall Defect: Consists of a buccal wall, a lingual wall, and one interproximal wall. These are ideal candidates for regenerative therapy or bone grafts.
• Furcation Involvement:
  • Class I: May not show signs on a radiograph.
  • Class II: Might show "hints" of involvement.
  • Class III: Definitely shows radiographic evidence.
  • Class IV: "Through-and-through" involvement where bone loss is clearly visible and the furcation is clinically open.
  • Difficulty in Upper Molars: Upper molars are harder to diagnose radiographically because the palatal root often blocks the view of the buccal furcation.

Limitations of Radiography

• Two-Dimensional Constraints: 2D films show interproximal surfaces well but tell nothing about the buccolingual surfaces.
• Clinical Gaps: Radiographs cannot:
  • Show soft tissue pockets or allow for pocket measurement.
  • Identify tooth mobility (though a widened PDL may hint at it).
  • Determine if a case is currently active or has already been treated/stabilized.
  • Show the true, complex morphology of bony defects.
• Underestimation of Loss: Radiographs can underestimate bone loss by up to $50\%$.
• Temporal Lag: Clinical attachment loss precedes radiographic bone loss by approximately six to eight months.

Systemic Links and Rapid Progression

• Rapid Bone Loss Case: The lecturer shared a case from the 1980s involving a patient who experienced dramatic bone loss in only two years. This was later linked to HIV.
• Systemic Factors: If dramatic changes are seen between radiographs, clinicians must investigate systemic issues like immune disorders or poorly controlled diabetes.

Advanced Imaging Technologies

• Digital Subtraction Radiography (DSR): Primarily used in research. It involves taking two images from the exact same position (using a stent) and superimposing them. The computer then highlights where bone has been lost (black arrows) or deposited (white arrows).
• CBCT (Cone Beam Computed Tomography):
  • Provides 3D sections of the tooth and bone.
  • Useful for identifying buccal/lingual "scooping" and complex 3-wall defects.
  • Indispensable for implant planning to avoid local anatomy such as the inferior alveolar nerve and the mental nerve.
  • Not used for day-to-day perio due to higher cost and radiation exposure compared to conventional films.

Mechanical Plaque Control Techniques

• Modified Bass Technique: The most common recommendation. Bristles are placed at a $45$-degree angle to the long axis of the tooth with a short vibratory motion. It targets the gingival margin.
• Modified Stillman Technique: Used for areas with recession or root exposure. Bristles are placed at the cervical area pointing apically, using a back-and-forth "shimmy" motion.
• Charter Technique: Used post-surgery (e.g., when suture marks are present). Bristles are at a $45$-degree angle to the tooth, using short circular strokes to massage the tissue.
• Importance of Soft Bristles: Patients should always use soft brushes to avoid traumatizing tissue or causing cemental abrasion.

Interdental Cleaning and Aids

• Gingival Embrasure Types:
  • Type I: Papilla completely fills the space. (Use floss).
  • Type II: $75\%$ of the space is filled. (Use floss or dental tape).
  • Type III: At least $50\%$ of the papilla is gone. (Use proxy brushes or larger aids).
• Interdental Aids:
  • Dental Floss: Waxed vs. unwaxed (lecturer prefers whatever the patient will use, mentions Cocoa Floss). Helps remove interproximal plaque.
  • Floss Threaders: For bridges, orthodontics, or tight contacts.
  • Proxy Brushes (Interproximal Brushes): Best for cleaning concavities and Type III embrasures. Size must be fitted correctly; it should not be jammed in or be too loose.
  • Stim-U-Dents: Triangular toothpicks for wider spaces.
  • End-Tuft Brush: Highly versatile for distal of molars, furcations, pontics, and orthodontic appliances.
  • Rubber Tips: Mainly used post-surgery to massage tissue and improve contours.

Patient Motivation and Education

• The "Charlie Brown" Effect: Clinicians should avoid nagging patients or sounding like the unintelligible adults in Charlie Brown. Constant criticism leads to patient disengagement.
• Motivational Strategies:
  • Social Motivation: For teenagers, appeal to their social life (e.g., fresh breath for dating).
  • Financial Motivation: Frame oral hygiene as a financial investment to avoid expensive future treatments.
• Repetition: Plaque control education requires multiple visits to tweak habits and observe responses.

Questions & Discussion

• Question (Kyle): What is a good use for a Panorex?
  • Response: Viewing anatomical structures like sinuses and nerves, detecting pathology, and initial implant planning.
• Question (Kevin): What do you see on this bitewing?
  • Response: The second molar is damaged/fractured with significant caries.
• Question (Magnus): Anything else on the bitewing?
  • Response: Radiographic calculus, which indicates the clinical amount is likely even higher.
• Question (Matt): Is there furcation involvement?
  • Response: There is a suggestion of it. To confirm, a Nabers probe must be used clinically.
• Question (Victor): What is the classification of this osseous defect?
  • Response: It is a three-wall defect (buccal, lingual, and interproximal walls present).
• Question (Tiffany): What is the treatment plan for a tooth with a clear vertical fracture?
  • Response: Extraction and replacement with an implant, bridge, or partial.
• Question (Aiden): What do you see on this PA?
  • Response: Significant bone loss, a tooth restored with an endo crown/root canal, and a nearby sinus landmark.
• Question (Student): Can we suggest composite to fill an open embrasure?
  • Response: No, because composite is plaque-retentive. It is better to have an open, cleansable embrasure than a bulky, closed one that the patient cannot clean.