X rays

Why X-rays for dentistry?

X-rays can penetrate hard tissues

What is a skiagram?

a shadow picture

A skiagram is another term for an X-ray image or radiograph.

It is a shadow-like image created by passing X-rays through an object, typically the human body, to visualize internal structures like bones, organs, or tissues.

Source of X-rays

X-ray tube

Electrons hitting target of tungsten in X-ray tube

High voltage puts in energy

Produces X-ray photons (packets of energy)

Image receptors for X-ray imagining

Analogue (film) or digital detectors

What is key to X-ray imagining?

Differential absorption of X-rays in different tissues

Some pass through, some are absorbed and some reflect back

What is the bitewing intraoral radiograph?

A bitewing intraoral radiograph is a specific type of dental X-ray that captures detailed images of the upper and lower teeth in a single area, typically focusing on the back teeth (premolars and molars).

It is called "bitewing" because the patient bites down on a small wing-shaped tab or holder attached to the X-ray film or sensor to keep it in place during the imaging process.

What determines how many X-rays are absorbed by material or tissue?

Atomic Number

Density

Thickness

Radiolucent

most or all X-rays pass through the structures to hit the image receptor -> producing dark image

Radiopaque

Most or all X-rays absorbed by the structures, with less to hit the image receptor -> producing light image

Lamina dura

socket of the teeth

CT scan compared X-rays?

CT scan uses higher energy C-rays and more sensitive detectors

Can differentiate some soft tissues

Fat absorbs fewer X-rays than other soft tissues

Caries

involves demineralisation of enamel and dentine

Periapical radiography

Periapical radiography is a type of dental X-ray that focuses on capturing the entire structure of one or more teeth, including both the crown (the visible part of the tooth) and the root (the part embedded in the jawbone), as well as the surrounding bone

Panoramic radiography

Panoramic radiography, also known as a panoramic X-ray or panorex, is a type of extraoral dental imaging that provides a broad, two-dimensional view of the entire mouth, including the teeth, upper and lower jaws, sinuses, and surrounding bone structures. Unlike bitewing or periapical radiographs, which focus on smaller areas within the mouth, panoramic radiographs capture a comprehensive image from a single scan

What is an OPG?

OPG stands for Orthopantomogram, which is another term for a panoramic dental X-ray.

An OPG provides a wide, two-dimensional view of the entire mouth, capturing the teeth, upper and lower jaws, and surrounding structures in a single image.

This type of imaging is commonly used in dentistry and orthodontics to get a broad perspective on oral health.

Features of panoramic radiography

Very sensitive to mistakes in positioning patient

Leads to incorrect horizontal magnification

Uses of panoramic radiography

Large or remote abnormalities not suitable for seeing on intraoral radiographs

Identifying presence and position of developing teeth for patients who have a critical need for orthodontic treatment

What is Cone Beam Computed Tomography (CBCT)?

Simple form of CT scanning allowing relatively cheap equipment to be available to dental practices