Radiology Topic 7

Identification of Restorations, Dental Materials, and Foreign Objects

Introduction

Purpose: To review common dental restorations, dental materials, and foreign objects that may be seen on dental images.
Interpretation of Dental Images:
- Dental professionals are encouraged to interpret all dental images while the patient is present. - Important clinical information may be missing when images are interpreted without the patient present.

Identification of Restorations

Types of Restorations

Amalgam restorations
Gold restorations
Stainless steel and chrome crowns
Post and core restorations
Porcelain restorations
Composite restorations
Acrylic restorations

Identification of Restorations (Details)

Metallic Restorations - Metallic restorations absorb x-rays, meaning little radiation reaches the receptor. - The receptor area under the metallic restoration remains unexposed, resulting in a completely radiopaque appearance on a dental image.
Nonmetallic Restorations - Appearance varies from radiolucent to slightly radiopaque, depending on material density. - Porcelain: most dense and least radiolucent. - Acrylic: least dense and most radiolucent.

Amalgam Restorations

One-Surface Amalgam Restorations:
- Appears as small, distinct, round or void radiopacities on buccal, lingual, or occlusal surfaces.
- Two-surface and multisurface amalgam restorations appear radiopaque with irregular outlines or borders.
Amalgam Overhangs:
- Extensions of amalgam seen beyond the crown portion of a tooth in the interproximal region. - Disrupts natural cleansing contours of the tooth and may contribute to food and plaque trapping as well as bone loss.
Amalgam Fragments:
- May become embedded in soft tissue during restoration, appearing as dense radiopacities with irregular borders.

Gold Restorations

Gold restorations appear completely radiopaque, characterized by a smooth marginal outline. - Gold Crowns and Bridges: Large radiopaque restorations with smooth contours and regular borders. - Gold Foil Restorations: Small, round radiopacities.

Stainless Steel and Chrome Crowns

These appear radiopaque but are not as dense as amalgam or gold.
They exhibit smooth outlines and margins, with some areas possibly appearing "see-through" on an image.

Post and Core Restorations

Found in endodontically treated teeth, appearing radiopaque on images.
Resembles the prepared portion of a tooth crown; the post extends into the pulp canal.

Porcelain Restorations

Porcelain restorations exhibit slight radiopacity resembling dentin.
All-Porcelain Crowns and Bridges:
- May show a thin radiopaque line, indicating cement, outlining the prepared tooth.
Porcelain-Fused-to-Metal Crowns:
- The metal component is completely radiopaque, while the porcelain component is slightly radiopaque.

Composite Restorations

Vary in appearance from radiolucent to slightly radiopaque based on the composition of the composite material.

Acrylic Restorations

Commonly used for interim or temporary crowns or fillings.
Acrylic is the least dense of nonmetallic restorations and appears radiopaque or barely visible on dental images.

Identification of Materials Used in Dentistry

Categories:
  - Restorative Dentistry
  - Endodontics
  - Prosthodontics
  - Orthodontics
  - Oral Surgery

Materials Used in Restorative Dentistry

Base Materials:
- Used as cavity liners; placed on cavity floors to protect the pulp. - Appear radiopaque and are less radiodense than amalgam.
Metallic Pins:
- Used to enhance retention of amalgam or composite materials. - Seen as cylindrical or screw-shaped radiopacities.

Materials Used in Endodontics

Gutta Percha:
- Clay-like material used to fill pulp canals, appears radiopaque and is less radiodense than metallic restorations.
Silver Points:
- Used for pulp canal filling, these appear very radiopaque, often more radiodense than gutta percha.

Materials Used in Prosthodontics

Complete and Partial Dentures:
- Patients must remove dentures before obtaining dental images. - Non-removal can create the illusion of rootless or "floating" teeth. - Removable partial dentures (RPD) with metal bases appear densely radiopaque, while acrylic saddles appear slightly radiopaque.

Materials Used in Orthodontics

Orthodontic Bands, Brackets, and Wires:
- Can be observed on dental images with characteristic appearances.

Materials Used in Oral Surgery

Implants:
- Increased use; appearance varies based on implants' shape and design.
Sutures, Metallic Splints, Plates, Bone Screws, Stabilizing Arches:
- Used for stabilizing maxilla and mandible fractures.

Identification of Objects

Jewelry: Metal earrings appear as dense radiopacities; artifacts known as ghost images occur, obscuring diagnostic information.
Eyeglasses: Metal portions appear as radiopacities on dental images.
Napkin Chains: Can appear on extraoral images.
Hearing Aids: Should be removed if containing metal components before taking extraoral images.
Shrapnel: Scattered fragments may also be viewed on dental images.

Interpretation of Dental Caries

Introduction

Purpose: Describe dental caries and detect caries, offering tips for interpretation and factors influencing it.
Classification: Introduces different classifications of caries visible on dental images.

Description of Caries

Caries: Defined as the localized destruction of teeth by microorganisms.

Detection of Caries

Methods:
- Clinical examination and dental image examination are both necessary.
- Dental images help detect carious lesions not visible clinically and allow evaluation of their extent and severity.

Clinical Examination

Some carious lesions are visible in the mouth; others require tools such as mirrors or explorers.
Signs:
- Color changes, dark staining in fissures, chalky white spots on smooth surfaces, and discoloration in interproximal ridges.

Dental Image Examination

Carious areas appear radiolucent, allowing penetrative imaging to identify lesions.
Image Types:
- Bite-wing images provide maximum diagnostic information; periapical exposures may also be utilized.

Interpretation of Caries on Dental Images

Interpretation Tips: Proper film mounting, viewing in subdued light, illuminators, and magnifiers aid in analyzing images.
Factors Influencing Interpretation:
- Quality of dental images matters; examples of errors include improper horizontal angulation or exposure issues.

Classification of Caries

Types include:
  1. Interproximal caries.
  2. Occlusal caries.
  3. Buccal and lingual caries.
  4. Root surface caries.
  5. Recurrent caries.
  6. Rampant caries.

Interproximal Caries

Typically seen just below the contact point on dental images and adopts a triangular shape as it progresses.
Classification:
1. Incipient: Less than halfway through the enamel. 2. Moderate: More than halfway through but not reaching DEJ (Dentin Enamel Junction). 3. Advanced: Extends to or through DEJ but does not reach the pulp. 4. Severe: More than halfway towards the pulp, possibly developing cavitation.

Occlusal Caries

Involve the chewing surfaces of posterior teeth; early forms are difficult to detect on images.
Types:
  - Incipient: Invisible on images, detectable only with an explorer.
  - Moderate: Extends into dentin, visible as a thin radiolucent line.
  - Severe: Radiolucency under enamel; diagnostic complexities arise with deep lesions.

Buccal and Lingual Caries

Difficult to detect on images, often superimposed on tooth structure, shown as circular radiolucent areas when present.

Root Surface Caries

Involves root areas below the CEJ, appearing crater-shaped on images, early lesions may go undetected.

Recurrent Caries

Located adjacent to existing restorations, appearing as radiolucent areas beneath these areas.

Rampant Caries

Advanced stages affecting multiple teeth, primarily seen in children with poor diets or in adults with decreased salivary flow.

Conditions Resembling Caries

Cervical Burnout:
- A radiolucent artifact appearing as a collar-shaped area near the CEJ.
Restorative Materials:
- Differentiated by smooth outlines compared to caries.
Attrition:
- Wear of teeth under mechanical forces manifesting as concavities.
Abrasion:
- Friction from external objects, presenting as polished defects, distinguishing them from root caries.

Interpretation of Periodontal Disease

Introduction

Purpose: Introduce the dental radiographer to describing and detecting periodontal disease, focusing on image interpretation of bone loss and predisposing factors.

Description of the Periodontium

Lamina Dura:
- A dense radiopaque line in healthy teeth.
Alveolar Crest:
- 1.5-2 mm below CEJ in healthy teeth; sharper in anterior and flatter in posterior.
Periodontal Ligament Space:
- Appears as a thin radiolucent line between tooth root and lamina dura, continuous and uniform in healthy conditions.

Description of Periodontal Disease

Affects surrounding tissue; ranges from inflammation to destruction of bone and periodontal ligament.
Symptoms include swelling, redness, bleeding, and pocket formation.

Detection of Periodontal Disease

Requires both clinical and dental image examinations, providing complementary information.
A clinical exam looks for signs like inflammation, while image exams focus on bone condition.

Clinical Examination

Conducted by dentists and dental hygienists, assessing soft tissue signs for inflammation and probing periodontal depth.

Dental Image Examination

Provides an overview of bone presence and the extent of loss. The periapical image is the choice method for evaluating periodontal disease.
Image Techniques:
- Paralleling technique preferred; bite-wing images offer limited detection; panoramic images have little diagnostic value.

Interpretation of Periodontal Disease on Dental Images

All images must evaluate bone loss and identify predisposing factors contributing to disease.

Bone Loss

Estimated by the difference between physiological bone level and remaining bone height; can be classified as follows: - Pattern: Horizontal or vertical. - Distribution: Localized (<30% sites involved) or generalized (>30% sites involved). - Severity: Classified as slight (1-2 mm), moderate (3-4 mm), and severe (5 mm or greater).

Classification of Periodontal Disease

Stage I: Bone loss in coronal third of root (<15%).
Stage II: Bone loss between 15%-33%.
Stage III: Extending to mid-third of root, with vertical loss and furcation involvement.
Stage IV: Extending beyond mid-third, with vertical loss, furcation, and tooth mobility.

Progression of Periodontal Disease

Inflammation is a first sign; untreated inflammation leads to mild periodontitis and further bone loss can lead to radiolucent areas in furcation.

Predisposing Factors

Local irritants such as calculus and defective restorations can contribute to periodontal disease; elimination is crucial to treatment.

Calculus

Resulting from plaque mineralization, appears as white or light angled projections on dental images.

Defective Restorations

Faulty restorations can trap food and lead to bacterial accumulation; identified through poor contour, open contacts, and overhangs in dental images.

Interpretation of Trauma, Pulpal Lesions, and Periapical Lesions

Introduction

Purpose: To provide an overview of common trauma and pulpal/periapical lesions as viewed on dental images.

Trauma Viewed on Dental Images

Fractures:
- Affect teeth crowns, roots, maxilla, and mandible.
Types of Fractures:
- Crown Fractures: Commonly in anterior teeth, affecting enamel, dentin, and/or pulp. - Root Fractures: Often vertical/horizontal, can be missed if x-ray is not parallel to fracture plane. - Jaw Fractures: Best visualized with panoramic images; appear as radiolucent lines on images.

Injuries

Includes tooth displacement characterized by luxation (intrusion & extrusion) and avulsion (complete tooth displacement).

Dental Resorption

External Resorption:
- Seen along root periphery, associated with reimplanted teeth, trauma, inflammation, etc.
Internal Resorption:
- Involves the pulp chamber and may result from trauma. Appears as round-to-ovoid radiolucencies.

Pulpal Lesions Viewed on Dental Images

Can detect conditions such as pulpal sclerosis, pulpal obliteration, and pulpal stones, each differing in appearance on images.

Periapical Lesions

Includes periapical granuloma, cyst, and abscess; cannot diagnose based solely on imaging without correlation to clinical features.

Periapical Radiolucencies

Periapical Granuloma: Chronic mass of inflamed tissue at nonvital tooth apex; appears as a widened periodontal ligament space on dental images.
Periapical Cyst: Asymptomatic lesion developing from granuloma degeneration; treated similarly.
Periapical Abscess: Pus collection at the apex; may be acute (painful) or chronic (usually asymptomatic).

Periapical Radiopacities

Observed as condensing osteitis (well-defined radiopacity often associated with chronic pulpitis), sclerotic bone (radiopacity below roots of vital teeth), and hypercementosis (excess cementum deposition).

Conclusion

Dental imaging provides vital information in diagnosing and interpreting restorations, materials, caries, periodontal disease, trauma, and lesions, aiding in effective dental management and treatment.