Dento-maxillary imaging
Course outline
- Introduction
- Anatomical reminder
- Exploration technique
- Result
- Normal/pathological
I) Introduction:
Despite the development of ultrasound, CT and MRI, radiography is still essential for diagnosis in dento-maxillofacial pathology. In this field, analog radiology is now being supplanted by digital radiology. We will first consider the principles of radiology in its two forms, analog and digital. Secondly, the specific techniques of dento-maxillofacial imaging will be discussed, emphasizing the recent development of cone beam computed tomography.
II) Anatomical reminders:
Paired bone above the oral cavity and below the orbital cavities and outside the nasal cavities.
Triangular shape with 04 faces : jugal, temporal, orbital, nasal
Three processes : zygomatic, palatine, frontal.
A maxillary sinus
III) Exploration techniques
-1) Standard X-ray
The image formation is done schematically in ten four stages within a radiological chain:
- X-ray production (XR)
- Formation of the radiant image
- Radiant Image Detection
- Presentation of the final image.
Other techniques:
- 2) Teleradiography
Without deformation and with real size.
- 3) Orthopantomography (Dental Panoramic)
Two types: slit scanning or tomographic scanning.
- 4) Cone beam computed tomography
Tube and integral detector rotating 360° with X-ray emission at each degree of rotation (totaling 360 images) therefore 3D views
System composition :
1) Stand with ray source + detector pair.
2) Table
3) Ray generator
4) Reconstruction software
- Main indications:
- ATM
- orthodontics
- Pre-implant assessment
- Maxillary sinus
- Impacted and ectopic tooth
- Tumor pathology
- Advantage
Low dose: 6 times lower than a scanner and slightly higher than a panoramic
3D Acquisition
Metallic artifacts (tolerable)
Price lower than a TDM
- Inconvenient
Spatial resolution
Duration (70 seconds).
5) TDM
Dental scanner
6) MRI
Limited space; interest in the assessment of the extension of bone tumors and the study of the ATM
IV) Result
- Normal
- The tooth;
- Support structures: periodontal, bone, alveolar;
- Neighboring anatomical elements.
- Incisors
The simplest anatomical model, in a median (or mesial) location, two in number (central incisor and lateral incisor) on each
hemiarcade, we will take them as a type of description.
The crown , the part visible during clinical examination, is characterized by its flattened shape and its sharp occlusal edge.
The root , an intraosseous part embedded in the alveolar cavity, is not accessible to direct vision. The incisor is a tooth
single-rooted.
The collar is the junction area between the crown and the root.
The tooth consists of a moderately radiopaque fundamental substance or dentin, covered at the crown level with a protective, hard, highly radiopaque layer of enamel.
Canines
Also single-rooted, they are characterized by the conical shape of their crown covered with a thick layer of enamel and the length of their root. There is one canine per hemiarch placed between the incisors and premolars.
Premolars
There are two of them per hemiarch and they are placed distally in relation to the canine.
Temporary molars
These are birooted baby teeth that precede the premolars, which owe their name to their shape comparable to that of the molars.
Permanent molars
They are not preceded by lacteal equivalents. There are three of them, located distally on each hemiarcade, and they have a
cubic crown and several roots.
The maxillary molars have in principle three roots (palatal root, mesiovestibular root and distovestibular root).
Mandibular molars are usually birooted (mesial-bicanal root and distal root).
Support structures
The dental roots are embedded in cavities or alveoli excavated in the alveolar bone. The alveolus is limited by a dense line of bone
: the lamina dura or alveolar wall. The alveolar bone interposed between the teeth constitutes the interdental septum. In contact with the gum
(radiolucent), the upper limit of the alveolar bone is called the alveolar crest. It is normally located at the level of the neck of the tooth.
The root and alveolus are united by a complex ligament system or desmodontium which appears on the images as a clear line bordering the root and separating it from the alveolar wall.
Neighborhood anatomical elements
Some anatomical projections can lead to erroneous assessments. This is most often the case for cavities (maxillary sinuses, nasal fossae, bony canals, sutures, depressions, vascular images, etc.) than for reliefs (muscle ridges). The panoramic image, with its possibility of right-left comparison and its exploratory dimensions, offers a priori in this circumstance fewer difficulties of interpretation than the intraoral image.
- Pathological
- Congenital
- Number anomaly: agenesis or supernumerary tooth.
- Size abnormality: gigantism or dwarfism (rice grain teeth).
- Shape anomaly.
- Structural anomaly.
- Situational anomalies: transposition, inclusion, ectopia.
- Acquired
- 1) Trauma
- 2) Infectious
Caries
These are areas of decalcification creating a gap with blurred edges at the level of the crown, the neck and sometimes the roots in the panoramic image; care must be taken not to diagnose a cavity in front of a half-tone image on the periphery of the tooth.
Periodontal infection
Ranging from desmodentitis which causes a widening of the alveolodental ligament to apicodental cyst.
Periapical granuloma is a smaller lacuna than the teardrop cyst.
– Pericoronitis
– Cellulite and abscesses
– Sinusitis: unilateral, they always have a dental origin, often a periapical lesion of a premolar or a molar
- Tumor
Mucous cysts: gingival, nasolabial, odontogenic
Bone cysts: radicular cyst (root), dentigerous cyst ( pericoronary )
Odontogenic lesion: ameoblastoma, epidermoid odontogenic tumor
Mesenchymal odontogenic lesion : fibroma myxoma.
Malignant odontogenic lesion: malignant ameloblastoma, intravenous carcinoma
Non-odontogenic lesion: cemento-ossifying fibroma, osteoblastoma, exostosis, nerve tumors, cartilaginous tumors
- Dysplastic lesion:
Fibrous dysplasia, cementary dysplasia, PAGET, enostosis, solitary cyst, aneurysmal cyst,
Inflammatory lesion: osteitis and osteomyelitis.
- ATM pathology:
Condylar dysmorphia, dislocation, ankylosis, osteoarthritis
Conclusion
Various pathologies, varied means of exploration, key role of the CONE BEAM.
Dento-maxillary imaging
Wisdom teeth can cause infections if not removed.
Dental crowns restore the function and appearance of damaged teeth.
Swollen gums are often a sign of periodontal disease.
Orthodontic treatments can be performed at any age.
Composite fillings are discreet and durable.
Composite fillings are discreet and durable.
Interdental brushes effectively clean tight spaces.
Visiting the dentist every six months prevents dental problems.