Rad Final Flashcards
Bisecting technique is based on a simple geometric principle known as ?
What does it state?
Rule of isometry
States that 2 triangles are equal if they have 2 equal angles and share a common side
In the bisecting technique the film must be placed on the
Lingual surface of the tooth
Where the film ____ the tooth, the plane of the film and the long axis of the tooth form and angle. What should we do with this angle
Contacts
Bisect this angle
The central ray is directed _____ to the bisector so 2 imaginary _____ triangles are formed
Perpendicular; equal
What is the finger holding method
Patients finger or thumb is used to stabilize the periapical film
Disadvantages of the finger holding technique
Unnecessary radiation
Distorted images
Inadequate exposure of prescribed area
Max Incisors vertical angulation of PID
+40-50
Mand incisors PID angulation
-15-25
Max canines PID angulation
+45-55
Mand canines PID angulation
-20-30
Max premolars PID angulation
+30-40
Mand premolars PID angulation
-10-15
Max molars PID angulation
+20-30
Mand molars PID angulation
-5-0
Incorrect vertical angulation results in an image that is
Foreshortened or elongated
In foreshortening the PID is angled too
Steep; short image; excessive vertical angulation
If an image is elongated the PID is too
Flat; long image; insufficient vertical angulation
Incorrect horizontal angulation results in
An overlapped image
Advantages of bisecting technique
Can be used without film holding device
Exposure time is reduced
Disadvantages of bisecting technique
Image distortion
Angulation problems
If film holder not utilized clients hand is exposed in finger holding
Describe the proper direction of the central ray in the bisecting technique
Central ray is directed at an angle of 90 degrees to the imaginary bisector
Impacted teeth occur where
One tooth is prevented from erupting due to being wedged up against a neighbouring tooth
If a tooth is not breaking through the gum because of being under bone it is classified as
Embedded
Dental anomalies can result from a combination of
Intrinsic and extrinsic factors
Variation in anomalies can occur
Congenital (at or before birth)
Hereditary (by genetic makeup)
A congenital anomaly is sometimes the result of hereditary and may not show up until?
Years after birth
Familial tendency
When an anomaly occurs more frequently than usual in one family
Developmental anomaly
When the condition results during the formation and development of a dental structure
Most commonly supernumerary tooth is
Mesiodens (midline of maxillae) tooth erupting between max centrals
1st most common congenitally missing teeth
Maxillary third molars
(2nd most common max lateral incisors)
If primary teeth are congenitally missing, will permanent replacements also be missing?
Yes
What are the most common twinning abnormalities, both demonstrating enlarged crowns
Fusion and gemination
Which teeth are most commonly affected by dens in dente
Maxillary lateral incisors
Dilaceration refers to distortion in root or crown of angle rage ____? Most common in?
45-90
Mandibular third molars
Genination
Double fused teeth; one bud but 2 crowns
*single root, common pulp, notched incisally
Bifid tooth/bifurcated crown
A tooth split into 2 crowns with one root
Twinning
Occurs when a single tooth germ splits forming 2 almost identical teeth but remaining fused as one
Fusion of tooth germs involves ONLY
Dentin
Fusion or growing together of two teeth at the root ONLY VIA CEMENTUM
Concresence
First appears as radiololucent area and later radiopaque as it becomes mineralized
Hypercementosis
Generalized cementum deposition is a feature of a condition known as ____ of bone
Pagets disease
Enamel pearls are found
On distal 3rd molars and buccal root furcation of molars. Not found on single rooted teeth
Enamel hypoplasia inhibits
Enamel formation
Enamel hypocalcification is caused by a condition that inhibits the calcification of enamel. What are the most common forms
Enamel fluorosis
Turners tooth
Anelogenesis imperfecta
Turners tooth is most common on
Maxillary incisor
Amelogenesis imperfecta is characterized by
Thin enamel stained various shades of yellow and brown and easily fractures away
What is the most unique feature of dentinogenesis imperfecta
Pulp chambers and root canal are usually completely filled in with dentin
Most common malformed anterior tooth is
Maxillary lateral incisor (peg shaped)
The most common tooth with cusp variations
Mandibular second premolars
The most common tooth with accessory cusps or tubercles
Maxillary molars
Maxillary first premolars
Usually have 2 roots but 40% have 1 root
DICOM data
Universal format for handling storing and transmitting 3d images
Cone beam computed tomography (CBCT)
Term used to describe computer assisted digital imagine in dentistry
Uses of 3D imaging
Implant placement
Extraction or exposure of impacted teeth
Endo evaluation
Sinus evaluation
Tmj analysis
Ortho
Advantages of 3D imaging
More accurate images
Quick scanning time
Transports and saves images easily
Lower dose radiation
Disadvantages of digital imaging
Patient movement artifacts
Size of the field of view
Cost of equipment
Lack of training in image data
Gag reflex is aka
Pharyngeal reflex
Exposure sequencing
Start with anterior exposures, follow with premolar exposures prior to molar. Maxillary molars should be exposed last
Helpful hints when dealing with a patient with a gag reflex
Never suggest gagging
Reassure the client
Suggest breathing
Try to distract client
Try to reduce tactile stimuli
Use topical anesthetic
Physical disabilities include what
Vision impairment
Hearing impairment
Mobility impairment
Developmental disabilities refer to substantial impairment of mental or physical functioning that occurs before
Age 22 and is of indefinite duration
Why take radiographs on an edentulous client
Detective root tips, impacted teeth, cysts or tumours
Identify objects in alveolar bone
Establish position of normal anatomic landmarks
Observe quantity and quality of existing bone
How many films total would you take in an edentulous client
6 films total
Why does the metal crown not create a ghost image
Ghost images are created by anatomical structures or objects that are located outside of the zone of focus or image layer
If the tongue ____ with the palate during exposure of a panoramic film, a dark ______ shadow results that obscures the _______
Is not in contact; radiolucent; apices of the maxillary teeth
How do metallic restorations appear on radiograph
Completely radiopaque
*absorb X-ray
Nonmetallic restorations may vary in radiographic appearance from
Radiolucent to slightly radiopaque
*porcelain, most dense; least radiolucent
*acrylic, least dense; most radiolucent
*composite resin; dependant upon material
One surface amalgam restorations appear as
Distinct, small, round or ovoid radiopacities
Amalgam overhangs cause what (3)
Disrupts natural cleansing contours of the tooth, traps food and plaque and contributes to bone loss
Amalgam fragments appear as
Dense radiopacities with irregular borders
Gold crowns and amalgam restorations appear equally radiopaque on X-ray, however
Gold exhibits a smooth marginal outline
Stainless steel crowns can be identified on a X-ray by their
Smooth and regular margins
*appear radiopaque but not as densely as amalgam or gold
All porcelain crowns what may be evident through the slightly radiopaque porcelain crown
A thin radiopaque line outlining the prepared tooth that represents cement
What is the least dense of all nonmetallic restorations and appears radiolucent or barely visible on X-ray
Acrylic
Base materials appear
Radiopaque
Silver points used in the obliteration of the pulp canals appear ____ than gutta percha on a processed film
More radiodense
What are diatorics
Metal retention pins found on anterior porcelain denture teeth
*tiny dense radiopacities superimposed over porcelain denture teeth
A removable partial denture with a metal base and acrylic saddles appears
Densely radiopaque where metal is present and slightly radiopaque in the areas of acrylic
Oral surgery materials appear
Radiopaque varying in size shape and design
Buccal object rule
SLOB
S- same
L- lingual
O- opposite
B- buccal
SLOB rule: when the object in second exposed X-ray appears to have moved in the same direction as the shift of the PID the structure is positioned
To the lingual
SLOB rule: when the dental structure or object seen in 2nd X-ray exposed appears to have moved in opposite direction of PID movement the structure is
Positioned to the buccal
Right angle technique for orientation of structures
One pa is exposed using proper technique to show object then an occlusal film is exposed
They are compared to locate the object
Root fractures most commonly occur
In the maxillary central region
Root fractures appear how on pa xray
Sharp radiolucent line
Maxillary jaw fractures are typically
Difficult to detect on dental radiograph
The mandible is fractured more so than any other facial bone and include
The body
The ramus
The condyles
How will you see a mandibular jaw fracture on an X-ray
Evidence of a radiolucent line at the site where the bone has separated
Anterior alveolar fractures are
Most common
Labial plate fracture is more common than
A palatal plate fracture
Jaw fractures: when only the palatal or labial plates are affected it is
Difficult to identify on an intraoral radiograph
What is intrusion
Abnormal displacement of teeth into bone
What is extrusion
Abnormal displacement of teeth out of the bone
Intrusion and extrusion generally involve
Maxillary central incisors
Physiological resorption is evident with normal
Shedding of deciduous teeth
Pathologic resorption is a result of
Chronic inflammation abnormal pressure external forces or unknown causes
External resorption is seen along what surface? Most often seen in which teeth?
Seen along the periphery of the root surface
Most often seen on anterior teeth
What is external resorption associated with
Re-implanted teeth
Abnormal mechanical forces (braces)
Trauma
Chronic inflammation
Secondary to ortho trx
Radiographically how does external resorption look
Lamina dura and bone surrounding apex appears normal
-apical region appears blunted and the root length appears shorter than normal
Internal resorption is associated with
Trauma
Pulp capping
Pulp polyps
Clinically internal resorption, if seen, will exhibit a
Pinkish hue due to close proximity of the pulp tissue to the tooth surface
Internal resorption appears radiographically as
A round or ovoid radiolucency in the mid crown or mid root portion of a tooth
What is pulpal sclerosis
A diffuse calcification of the pulp chamber and pulp canals
What is pulpal sclerosis associated with and not associated with
Associated with aging
Not associated with inflammation, trauma or systemic disease
Pulpal sclerosis is of _____ unless endo therapy is indicated
Little clinical significance
Irritants to the pulp that lead to obliteration of the pulp cavity include
Attrition
Abrasion
Caries
Restorations
Trauma
Abnormal mechanical forces
Radiographically how does pulp obliteration look
Does not appear to have a pulp chamber so radiopaque structure that confirms to the shape of pulp chamber/canal
What are pulp stones
Calcifications found in pulp chamber or pulp canals
Pulp stones are located where?
Do they require treatment?
Located on the walls of the pulp cavity or completely surrounded by pulpal tissue.
No trx required
Are all periapical radiolucencies/lesions clinically asymptomatic
No, some can be symptomatic
Diagnosis of periapical radiolucencies is based on
Clinical features and microscopic appearance (need a histological exam)
What is a periapical granuloma
Localized mass of chronically inflamed granulation tissue at the apex of a NONVITAL tooth
Periapical granuloma is a result of
Necrotic pulp
Clinically periapical granuloma has prolonged history of
Hypersensitivity and percussion
How do periapical granulomas appear radiographically
Periapical round or ovoid unilocular radiolucent structure
*Lamina does not visible between apex of root and apical lesion
A periapical cyst is aka
What is it
Radicular cyst/ apical periodontal cyst
Results from cystic degeneration of the periapical granuloma (pulpal death/ necrosis )
Periapical cyst appears radiographically as
Round or ovoid unilocular radiolucency
Corticated or noncorticated borders
What is a periapical abscess
Localized collection of pus in the periapical region of a tooth
Periapical abscess clinically presents
Acute: painful, nonvital, sensitive to pressure heat and percussion
Chronic; usually asymptomatic pus drains through bone or PDL space
Periapical abscess appear radiographically
Increased widening of the PDL space
Apical round or ovoid unilocular radiolucency with diffuse or poorly defined margins
What is the most common radiopacity seen in adult clients
Condensing osteitis
Condensing osteitis is associated with
Non vital teeth with large caries or large restorations
* more evident in mand first molars
Condensing osteitis appear radiographically as
Well demarcated focal opacity situated below the apical third of a tooth
Sclerotic bone is aka idiopathic periapical osteosclerosis. It is a?
Well defined radiopacity seen below the apices of vital nonferrous teeth
*not attached to the tooth
What is hypercementosis and what area does it most often affect
Excess deposition of cementum on root surfaces
Most often affects apical area, which appears enlarged and bulbous
Teeth affected by hypercementosis are vital. Do they require trx?
No
Radiograph
Refers to actual film exposed
X-ray
Beam of energy or radiation
Radiolucent
Portion of a processed radiograph that is dark or black
Radiopaque
The portion of a processed radiograph that appears light or white
Radiolucent classifications may include
Moth eaten pattern
Multiracial pattern
Widened perio ligament
Unilocular radiolucent lesions usually indicative of
A benign, slow growing process
What is a corticated border
Thin and well demarcated radiopaque rim of bone at the periphery
What is noncorticated borders
Fuzzy and ill defined without a thin radiopaque rim of bone at the periphery
