October 13, 2025 • 18 mins
Focused on dental imaging and diagnosis. The content provides a comprehensive, question-and-answer format for students, covering fundamental concepts like normal anatomy seen in radiographs, the identification of dental materials and foreign objects, and the recognition of technique errors in both intraoral and panoramic radiography. A significant portion of the material is dedicated to the principles, devices, and practical use of digital imaging systems, including detailed steps for image acquisition and post-capture processing like histogram adjustments. Finally, the text also explores advanced topics such as radiation health and safety procedures and the assessment and interpretation of various dental anomalies and jaw pathologies through case-based questions and answers.
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Episode Transcript
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Speaker 1 (00:00):
Welcome to the Deep Dive today. Our mission really is
to give you a complete, shortcut, a detailed tour through
a super important text in dental education. Exercises in Oral
Radiology and Interpretation, fourth Edition. If you're a dental student,
maybe a new grad, or you know, anyone needing to
really lock down the basics of reading radiographs, this Deep
(00:20):
Dive is absolutely for you.
Speaker 2 (00:23):
Yeah, this book, it's genuinely foundational. And what's great about
it isn't just the depth, it's the author's whole approach
to teaching. The aim was clearly accessibility. It keeps the
language simple, uses this clear Q and a format, And
well I always liked the little touches aimed at reducing stress.
You know, those humorous asides like telling students to take
a break, maybe eat some chocolate.
Speaker 1 (00:44):
Uh yeah, I remember those. It shows a bit of
humanity which you don't always get.
Speaker 2 (00:47):
In textbooks exactly. It acknowledges this stuff is tough.
Speaker 1 (00:50):
For sure. It's a dense field. So okay, this fourth edition,
which came out in two thousand and four, it had
some pretty significant updates, didn't it physically even?
Speaker 2 (01:00):
Oh yeah, they cleaned up the images got rid of
most of those little arrows and numbers pointing everything out
on the actual radiograph.
Speaker 1 (01:07):
Which is interesting. Why do that?
Speaker 2 (01:09):
Well, they replaced them with separate diagrams showing the normal
anatomy side by side. The idea, I think was to
force you to really look at the radiograph itself like
you would clinically without the visual crutches. Makes sense simulating
the real world, right, And crucially for exams, they added
like three hundred new multiple choice questions, heavy focus on
(01:31):
the physics, the biology, digital stuff, infection control. QA really
positioned it as a keyboard prep tool.
Speaker 1 (01:38):
Okay, so better for self assessment. And they also hammered
home a key clinical point. Didn't they something about retakes?
Speaker 2 (01:45):
Absolutely? They expanded chapters with clinical photos, real scenarios, technique, errors,
and the constant message was every retake doubles the radiation dose, right,
doubles it. So mastering technique isn't just about getting a
pretty picture. It's fundamental patient safety. Avoiding that second shot
is well paramount.
Speaker 1 (02:03):
Okay, got it, Let's dive into those mechanics. Then chapter
one Normal Anatomy.
Speaker 2 (02:09):
The book really stresses repetition, right, matching the diagram to
the actual X ray.
Speaker 1 (02:13):
Yeah, whether it's intraoral or panoramic. It's all about recognizing
structures until it's second nature, that correlation diagram versus radiograph.
You only get it through practice, lots of practice.
Speaker 2 (02:25):
And that confidence can disappear pretty quick if you don't
get the geometry right, leading to distorted images exactly.
Speaker 1 (02:32):
That brings us to chapter three and four technique errors.
The two big distortions are elongation and foreshortening.
Speaker 2 (02:39):
Okay, break those down.
Speaker 1 (02:41):
Elongation where the teeth looks stretched out kind of long.
That happens if your positive vertical angle isn't steep enough,
or sometimes with the paralleling technique in the upper jaw,
if the film's too far from.
Speaker 2 (02:52):
The tooth so angle too flat. Teeth look long, got it,
and the opposite.
Speaker 1 (02:56):
Foreshortening teeth look stubby squashed. That's from too much vertical angulation,
too steep an angle right.
Speaker 2 (03:01):
And then there's the classic error everyone makes at some point,
the cone cut.
Speaker 1 (03:05):
Ah.
Speaker 2 (03:05):
Yes, that clear white area usually a curve or a
straight edge at the corner of the image. It just
means the beam coming out of the bid the barrel
didn't completely cover the sensor or film.
Speaker 1 (03:18):
Often because the positioning rod wasn't parallel to the bid precisely.
Speaker 2 (03:22):
Especially noticeable with rectangular colimation. If you're not lined up.
Speaker 1 (03:25):
Perfectly, a sign of maybe rushing things a bit. Okay,
so those are projection geometry errors. What about handling traditional
film still relevant for some?
Speaker 2 (03:35):
Definitely you need to recognize those artifacts like black lines
always from bending or crimping the film packet.
Speaker 1 (03:41):
Always okay, and chemical screw ups.
Speaker 2 (03:44):
Yeah, you gotta know the difference. White spots or patches
mean fixer solution got splashed on the film before it
went into the developer, it stopped development in that area.
Speaker 1 (03:51):
Fixer first, equal white spots and black spots opposite problem.
Speaker 2 (03:56):
Developer solutions splashed on before the film was properly immerged,
so it started developing too early in those spots.
Speaker 1 (04:02):
Okay, fix or white, developer black. What about those weird
lightning bolt looking V shaped black lines you sometimes see?
Speaker 2 (04:09):
Ah, that's not chemical or physical damage like bending. That's
static electricity. Yeah, usually means the dark room is too dry.
The fix is simple, increase the humidity. Humidifier usually does
the trick.
Speaker 1 (04:20):
Huh, good to know. Okay, so we nail the technique
avoid film errors next big thing is exposure physics. Dose
reduction is key inverse square law.
Speaker 2 (04:31):
Oh, absolutely fundamental. You have to understand this. If you
cut the distance from the source to the film in half,
say going from a long sixteen inch by D to
a short eight inch one, you need to cut the
exposure time down to one.
Speaker 1 (04:45):
Quarter one quarter, not half, No, one.
Speaker 2 (04:47):
Quarter, because the intensity increases by the square of the
distance change. So using that short cone without drastically cutting
the time means you're majorly over exposing the patient, like
by four hundred percent.
Speaker 1 (04:59):
Wow, that real underscores the safety benefit of the standard
sixteen inch cone. Then less fiddling with time, less risk
of massive error exactly.
Speaker 2 (05:06):
And then there's a rule of fifteen KVP. Basically, if
you increase your kill a voltage peak setting by fifteen,
you can cut your exposure time in half and get
roughly the same image density.
Speaker 1 (05:15):
Useful for balancing contrast and density while managing exposure time.
Speaker 2 (05:19):
Right and still on safety. The book points out that
as of two thousand and four, speedf film the brand
name was Insight, was the fastest film out there, the
best choice for minimizing patient dose with film.
Speaker 1 (05:30):
Okay, good baseline, Now let's shift gears to where most
practices are. Now we're heading digital. Section two. Hardware. First,
the main types of sensors.
Speaker 2 (05:42):
You've got basically two main camps for direct instant images
CCD charge coupled device and CMOS complementary metal oxide sensor.
These are the wired sensors you place, expose and boom
image on the.
Speaker 1 (05:54):
Screen wired instant and the other type.
Speaker 2 (05:57):
That's PSP or photostimulable phosphor plates. These are wireless, thin,
flexible like film, which makes positioning often a bit easier
and more comfortable for the patient.
Speaker 1 (06:05):
But they're not instant.
Speaker 2 (06:06):
No, you expose them, take them out of the mouth,
and then you have to run them through a laser scanner.
The scanner reads the stored energy the latent image and
turns it into the digital picture.
Speaker 1 (06:15):
Gotcha, So film like workflow but digital result. Now, why
is digital generally seen as superior? Resolution? Comes up a lot.
Speaker 2 (06:22):
Yeah, two key metrics. First is spatial resolution thinks sharpness
detail measured in line pairs per millimeter lpmm. Digital systems
can hit over twenty lpm.
Speaker 1 (06:33):
And how does that compare?
Speaker 2 (06:35):
Well, it actually beats what the human eye can typically resolve,
which is around twelve fourteen lpm, and it's better than
traditional film too, which is maybe eleven twelve lpmm.
Speaker 1 (06:44):
So potentially more detail capture than we can even see
without help.
Speaker 2 (06:48):
Kind of yeah, which leads to the second metric, grayscale
resolution or contrast measured in bits. Standard computer monitors are
eight bit, meaning they show two hundred and fifty six
shades of great okay, but the sensors can capture way more.
Some systems go up to twelve bits, which is over
four thousand shades of gray.
Speaker 1 (07:06):
Ooh, but wait, if our eyes only distinguish what maybe
sixteen or so shades easily, why capture thousands? Ah?
Speaker 2 (07:12):
That's the magic of digital processing. Having all that raw data,
all those shades means you can use software tools after
taking the shot to manipulate the image, like what kind
of tools? Things like histogram shifting, which lets you lighten
or darken the whole image without re exposing, or histogram stretching,
which changes the contrast range. You can apply sharpening filters,
smoothing filters invert the image to look like a negative,
(07:35):
even use an emboss filter to give it a sort
of three.
Speaker 1 (07:37):
D look so you can pull out details. That might
have been hidden in the initial view.
Speaker 2 (07:41):
Exactly. That's the big advantage. But digital isn't perfect. It
has its own unique errors.
Speaker 1 (07:47):
Right, Like overexposure on ccdcmos.
Speaker 2 (07:50):
Yeah, if you blast it with too much radiation you
get saturation. The very dark areas just bottom out, become
pure black, and you lose all detail there. It's gone.
You can't recover it with software.
Speaker 1 (08:01):
Okay. So overexposure is bad.
Speaker 2 (08:03):
Under exposure that leads to noise, the image looks grainy
or snowy. You lose detail in the lighter areas.
Speaker 1 (08:10):
And the PSP plates have their own special problem, right.
Speaker 2 (08:12):
Something about light, Yes, this is crucial. Unlike film, which
isn't really sensitive to visible light after exposure, PSP plates
are If you leave an exposed PSP plate sitting out
in room light, especially bright light, before.
Speaker 1 (08:26):
You scan it, it gets erased.
Speaker 2 (08:27):
It can. Yeah, the light erases the latent image, So
you need to protect them from light between exposure and scanning,
and also after scanning you have to deliberately expose them
to a bright light source to fully erase them before
you reuse them.
Speaker 1 (08:41):
Okay, handle with care regarding light. Let's move to panoramic imaging.
Chapter seven talks about six interpretive zones.
Speaker 2 (08:48):
What's the idea there, It's just a systematic way to
evaluate a panoramic image. Make sure you don't miss anything
and spot common errors. Zone one is the dentition itself.
The occlusal plane should have that gentle upward curve the
smile line.
Speaker 1 (09:02):
Okay.
Speaker 2 (09:03):
Zone two is the TMJs looking for symmetry, condole centered
roughly equal size. Zone three the mandible's lower border should
be smooth and continuous.
Speaker 1 (09:12):
Got it? Zones four five.
Speaker 2 (09:14):
Zone four is the nose and sinus area. You should
see turbinates, the hard palette shadow above the upper teeth roots.
Zone five involves the spine and ramis. Ideally, the spine
shouldn't be superimposed over the rainnis. Zone six is the
hyoid bone should look like mirror images on both sides,
not smeared across the jaw.
Speaker 1 (09:30):
Okay, So using those zones help spot positioning errors too.
What are the classic panel mistakes? Oh?
Speaker 2 (09:35):
Yeah, patient, too far forward in the machine you get skinny,
blurred front teeth, and classically you see a ghost image
of the spine laid right over the ramis area.
Speaker 1 (09:46):
Okay, too far forward, skinny teeth spawn ghost too far back.
Speaker 2 (09:51):
Then the interior teeth get wide and magnified, kind of
distorted and unreliable. The telltale sign, though, is often a
ghost image of the ramis itself appearing across the other side,
sometimes like a horizontal line dividing the body. In ramis.
You might also see the turbinates looking weirdly spread across
the sinus right and the.
Speaker 1 (10:08):
Chin positioning that's a big one. Chin too low.
Speaker 2 (10:11):
Creates that exaggerated smile line like a deep frown curving down.
It often cuts off the roots of the lower front
teeth and you get the hyoid bone ghosting across the mandible.
Really messes up the diagnostic value.
Speaker 1 (10:23):
Yeah, ruins the whole lower part of the image. What
about if the patient doesn't put their tongue on the
roof of their mouth.
Speaker 2 (10:27):
Ah Yeah, simple instruction fail. You see a big, dark,
radiolucent shadow arching over the roots of the maxillary teeth.
That airspace causes it. Easy to fix with better instructions
next time.
Speaker 1 (10:39):
Okay, let's move into diagnosis now. Chapter two covers recognizing
dental materials amalgam composite crowns. It's usually straightforward, but distinguishing
restorations from carries, especially near the gum line.
Speaker 2 (10:53):
Yes, that brings up the great impostor cervical burnout. It's
a radio lucent area looks dark like decay hay often
seen on the necks of teeth, especially like distal of
mandibular canines or premolars. Sometimes upper molars looks just like
root carries.
Speaker 1 (11:08):
So how do you tell the difference?
Speaker 2 (11:10):
This is critical key takeaway. Cervical burnout is an optical
artifact caused by the shape of the tooth and the
X ray angle. True Carries is actual missing tooth structure.
So if you suspect burnout, take another bite wing, but
change the horizontal angulation.
Speaker 1 (11:24):
Slightly change the angle, and.
Speaker 2 (11:25):
If that dark spot disappears or significantly changes shape on
the second film taken from a different angle, it was
cervical burnout, true Carries will still be there looking pretty
much the same brilliant.
Speaker 1 (11:35):
Okay, change the horizontal angle. Got it. The book also
details anomalies structural.
Speaker 2 (11:40):
Ones, yeah, things like dentinogenesis imperfecta. You see obliterated tiny
pulps and bulbous bell shaped crowns. Amelogenesis imperfecta has various
looks depending on the subtype, but it affects the enamel,
making it thin or poorly mineralized, and torridontism bull teeth,
big pulp chambers, short roots, no properfication.
Speaker 1 (12:03):
Recognizing those patterns is key. What about tooth number and
position issues.
Speaker 2 (12:08):
Well, Messiodins is the most common extra tooth found between
the upper central incisors. Concrescens is when two teeth are
joined only by their cementum. And a crucial measurement is
the follicular space around an unerupted tooth crown right.
Speaker 1 (12:20):
The space should be tubic.
Speaker 2 (12:22):
Exactly on an intraoral film. If it's wider than about
two point five millimeters or three milimeters on a panel,
you start worrying about pathology like a dentigerous cyst.
Speaker 1 (12:30):
Forming okay, And if you find something weird, like an
impacted canine or a foreign object, you need to know
if it's on the cheek side or the tongue side.
Localization rules three.
Speaker 2 (12:38):
Main ones described. The classic is the Solb rule same
lingual opposite bookle. You take two shots, keeping the vertical
angle the same but changing the horizontal tube shift. If
the object moves in the same direction as the tube
shifted it's lingual. If it moves opposite to the tube shift,
it's bookele.
Speaker 1 (12:56):
Slob got it? What are the others?
Speaker 2 (12:59):
The bookle object rule sometimes called Richard's rule. It basically
says the object that is bookele or closer to the
cheek will move in the same direction as the cone
or be itself is moved between the two shots.
Speaker 1 (13:11):
Okay, bookele moves at the cone.
Speaker 2 (13:13):
And the third known object rule or lunglaze rule. This
one feels maybe more intuitive for some. You compare the
movement of your unknown object to the movement of a
known anatomical landmark nearby, like the zygomatic arch, bookele or
maybe the genial tubercules lingual. If your object moves with
a known bookle landmark, it's bookele. If it moves opposite,
it's lingual relative to that landmark.
Speaker 1 (13:35):
Right. Using landmarks as a reference, these rules are like
your diagnostic compass. Let's talk pathology signs from chapter eleven.
Cysts first ten.
Speaker 2 (13:43):
Tittorous cyst is a classic one around the crown of
an impacted tooth. That paraicronal radilucency. A primordial cyst is
interesting because it develops instead of a tooth. It takes
the place where a tooth should have formed, often turns
out to be an okac an odontogenetic, craticist.
Speaker 1 (14:00):
Okay, and lateral periodontal.
Speaker 2 (14:02):
Syst typically found on the side of a root, most
commonly in the mandibular canine premolar region, usually well defined
round or ovlucency.
Speaker 1 (14:10):
Tumors and displays have specific looks too.
Speaker 2 (14:13):
Definitely cemento blastoma. You see this dense radiopaque mass stuck
right to the root apex, but critically it's surrounded by
a thin, even radiolucent line or halo.
Speaker 1 (14:24):
That halo is key fibrous dysplasia.
Speaker 2 (14:26):
That's the one with the classic ground glass or sometimes
orange peel or fingerprint pattern. The bone looks kind of hazy,
trabecular or in distinct.
Speaker 1 (14:33):
And odonogenic mix alma sounds exotic.
Speaker 2 (14:36):
It has a very specific look, usually multilocular, meaning multiple compartments,
but the septa, the lines dividing the compartments are often straight,
thin and angular forming geometric shapes, sometimes described as looking
like a tennis racket or a fish skeleton inside very distinctive.
Speaker 1 (14:51):
Wow, Okay, memorize those patterns. What about signs of aggressive
disease or systemic issues.
Speaker 2 (14:57):
The floating tooth sign is a big red flag. It
looks like the tooth is just suspended in space because
the supporting bone around it has been rapidly destroyed. You
have to figure out why, is it super aggressive periodontal
disease or something more sinister like a malignancy, maybe metastatic cancer.
Urgent investigation needed.
Speaker 1 (15:16):
Scary stuff, any other systemic signs.
Speaker 2 (15:19):
Hyperparathyroidism can cause generalized bone demineralization, loss of the laminadura
that wideline around the tooth root, and sometimes these olytic
lesions called brown tumors. And the book also mentions the
punched out skull lesions you see in multiple myeloma.
Speaker 1 (15:33):
Okay, lots to recognize there. Let's wrap up by revisiting
chapter nine, Radiation, Health and Protection. What's the single best
way to cut patient dose?
Speaker 2 (15:42):
Hands down? Collimation Using a long sixteen inch rectangular bed
is the most effective method. The text states it reduces
the dose by something like three hundred percent to six
hundred percent compared to using even a long round.
Speaker 1 (15:53):
Bed, three to six times less radiation. That's huge, massive.
Speaker 2 (15:58):
In the book notes it was expected to become the
required standard for peri appicles because it's so much more
efficient at reducing unnecessary exposure.
Speaker 1 (16:06):
And machine type matters too.
Speaker 2 (16:07):
Yes, constant potential DC machines are better than the older
AC machines. They give about a twenty percent dose reduction
for the same image quality because they produce a more
consistent effective X ray beam without the lower energy photons
that just add to patient dose without improving the image.
Speaker 1 (16:24):
Better beam quality, less ed dose. What about lead aprons?
Speaker 2 (16:28):
Interestingly, the text mentions pending federal guidelines even back in
two thousand and four, suggesting that patient protective aprons might
eventually be discontinued, especially with digital imaging and rectangular colimation
becoming more standard. The beam is just so focused.
Speaker 1 (16:43):
That's a shift in thinking. Finally, infection control non negotiable.
Speaker 2 (16:47):
Right absolutely, It's federally mandated by OSHA. The key distinction
the book makes is between sterilization killing everything, including tough
bacterial spores like TB, which is required for instruments that
penetrate tissue critical items, and disinfection, which kills most pathogens
but not necessarily all spores.
Speaker 1 (17:04):
And the crucial point for digital sensors.
Speaker 2 (17:06):
You cannot heat sterilize them in an autoclave, they'll be destroyed.
So they require meticulous use of protective barriers and intermediate
level surface disinfection between patients following manufacture instructions is critical.
Speaker 1 (17:18):
Okay, So all this knowledge, anatomy, technique, errors, pathology, safety,
it all comes back to that core idea, doesn't it exactly?
Speaker 2 (17:27):
The eye cannot see what the mind does not know.
If you haven't learned what normal looks like, how errors manifest,
and what the signs of disease are, you just won't
see them on the radiograph, and.
Speaker 1 (17:37):
You'll end up taking more pictures than necessary, increasing dose,
or worse, missing something important.
Speaker 2 (17:43):
Precisely mastering this stuff minimizes retakes and maximizes your diagnostic
ability for every single image.
Speaker 1 (17:50):
All right, let's solidify one of those diagnostic decision points.
Here's a quick scenario for you listening. You take a
bite wing and you see a dark spot, a radio
lousence on the distal surface of a lower first molar
near the gum line. You suspect root carries, but you
remember cervical burnout. To definitively rule out burnout, What specific
(18:11):
change do you make for the next image, and how
will that dark spot look if it is just burnout?
Speaker 2 (18:16):
Okay, the key change is you must alter the horizontal
angulation of the X ray beam for the second bite wing.
Keep the vertical angle the same, but shift the tube
head slightly measily or distally, and the result if that
radiolycent spot essentially disappears or drastically changes shape on the
second image taken with a different horizontal angle, then you've
confirmed it was the artifact cervical burnout, not true decay.
Speaker 1 (18:39):
Confidence confirmed excellent, rule out the artifact. Trust your diagnosis.
Thanks for joining us for this deep dive into the
foundations of oral radiology.
Welcome to the Deep Dive today. Our mission really is
to give you a complete, shortcut, a detailed tour through
a super important text in dental education. Exercises in Oral
Radiology and Interpretation, fourth Edition. If you're a dental student,
maybe a new grad, or you know, anyone needing to
really lock down the basics of reading radiographs, this Deep
(00:20):
Dive is absolutely for you.
Speaker 2 (00:23):
Yeah, this book, it's genuinely foundational. And what's great about
it isn't just the depth, it's the author's whole approach
to teaching. The aim was clearly accessibility. It keeps the
language simple, uses this clear Q and a format, And
well I always liked the little touches aimed at reducing stress.
You know, those humorous asides like telling students to take
a break, maybe eat some chocolate.
Speaker 1 (00:44):
Uh yeah, I remember those. It shows a bit of
humanity which you don't always get.
Speaker 2 (00:47):
In textbooks exactly. It acknowledges this stuff is tough.
Speaker 1 (00:50):
For sure. It's a dense field. So okay, this fourth edition,
which came out in two thousand and four, it had
some pretty significant updates, didn't it physically even?
Speaker 2 (01:00):
Oh yeah, they cleaned up the images got rid of
most of those little arrows and numbers pointing everything out
on the actual radiograph.
Speaker 1 (01:07):
Which is interesting. Why do that?
Speaker 2 (01:09):
Well, they replaced them with separate diagrams showing the normal
anatomy side by side. The idea, I think was to
force you to really look at the radiograph itself like
you would clinically without the visual crutches. Makes sense simulating
the real world, right, And crucially for exams, they added
like three hundred new multiple choice questions, heavy focus on
(01:31):
the physics, the biology, digital stuff, infection control. QA really
positioned it as a keyboard prep tool.
Speaker 1 (01:38):
Okay, so better for self assessment. And they also hammered
home a key clinical point. Didn't they something about retakes?
Speaker 2 (01:45):
Absolutely? They expanded chapters with clinical photos, real scenarios, technique, errors,
and the constant message was every retake doubles the radiation dose, right,
doubles it. So mastering technique isn't just about getting a
pretty picture. It's fundamental patient safety. Avoiding that second shot
is well paramount.
Speaker 1 (02:03):
Okay, got it, Let's dive into those mechanics. Then chapter
one Normal Anatomy.
Speaker 2 (02:09):
The book really stresses repetition, right, matching the diagram to
the actual X ray.
Speaker 1 (02:13):
Yeah, whether it's intraoral or panoramic. It's all about recognizing
structures until it's second nature, that correlation diagram versus radiograph.
You only get it through practice, lots of practice.
Speaker 2 (02:25):
And that confidence can disappear pretty quick if you don't
get the geometry right, leading to distorted images exactly.
Speaker 1 (02:32):
That brings us to chapter three and four technique errors.
The two big distortions are elongation and foreshortening.
Speaker 2 (02:39):
Okay, break those down.
Speaker 1 (02:41):
Elongation where the teeth looks stretched out kind of long.
That happens if your positive vertical angle isn't steep enough,
or sometimes with the paralleling technique in the upper jaw,
if the film's too far from.
Speaker 2 (02:52):
The tooth so angle too flat. Teeth look long, got it,
and the opposite.
Speaker 1 (02:56):
Foreshortening teeth look stubby squashed. That's from too much vertical angulation,
too steep an angle right.
Speaker 2 (03:01):
And then there's the classic error everyone makes at some point,
the cone cut.
Speaker 1 (03:05):
Ah.
Speaker 2 (03:05):
Yes, that clear white area usually a curve or a
straight edge at the corner of the image. It just
means the beam coming out of the bid the barrel
didn't completely cover the sensor or film.
Speaker 1 (03:18):
Often because the positioning rod wasn't parallel to the bid precisely.
Speaker 2 (03:22):
Especially noticeable with rectangular colimation. If you're not lined up.
Speaker 1 (03:25):
Perfectly, a sign of maybe rushing things a bit. Okay,
so those are projection geometry errors. What about handling traditional
film still relevant for some?
Speaker 2 (03:35):
Definitely you need to recognize those artifacts like black lines
always from bending or crimping the film packet.
Speaker 1 (03:41):
Always okay, and chemical screw ups.
Speaker 2 (03:44):
Yeah, you gotta know the difference. White spots or patches
mean fixer solution got splashed on the film before it
went into the developer, it stopped development in that area.
Speaker 1 (03:51):
Fixer first, equal white spots and black spots opposite problem.
Speaker 2 (03:56):
Developer solutions splashed on before the film was properly immerged,
so it started developing too early in those spots.
Speaker 1 (04:02):
Okay, fix or white, developer black. What about those weird
lightning bolt looking V shaped black lines you sometimes see?
Speaker 2 (04:09):
Ah, that's not chemical or physical damage like bending. That's
static electricity. Yeah, usually means the dark room is too dry.
The fix is simple, increase the humidity. Humidifier usually does
the trick.
Speaker 1 (04:20):
Huh, good to know. Okay, so we nail the technique
avoid film errors next big thing is exposure physics. Dose
reduction is key inverse square law.
Speaker 2 (04:31):
Oh, absolutely fundamental. You have to understand this. If you
cut the distance from the source to the film in half,
say going from a long sixteen inch by D to
a short eight inch one, you need to cut the
exposure time down to one.
Speaker 1 (04:45):
Quarter one quarter, not half, No, one.
Speaker 2 (04:47):
Quarter, because the intensity increases by the square of the
distance change. So using that short cone without drastically cutting
the time means you're majorly over exposing the patient, like
by four hundred percent.
Speaker 1 (04:59):
Wow, that real underscores the safety benefit of the standard
sixteen inch cone. Then less fiddling with time, less risk
of massive error exactly.
Speaker 2 (05:06):
And then there's a rule of fifteen KVP. Basically, if
you increase your kill a voltage peak setting by fifteen,
you can cut your exposure time in half and get
roughly the same image density.
Speaker 1 (05:15):
Useful for balancing contrast and density while managing exposure time.
Speaker 2 (05:19):
Right and still on safety. The book points out that
as of two thousand and four, speedf film the brand
name was Insight, was the fastest film out there, the
best choice for minimizing patient dose with film.
Speaker 1 (05:30):
Okay, good baseline, Now let's shift gears to where most
practices are. Now we're heading digital. Section two. Hardware. First,
the main types of sensors.
Speaker 2 (05:42):
You've got basically two main camps for direct instant images
CCD charge coupled device and CMOS complementary metal oxide sensor.
These are the wired sensors you place, expose and boom
image on the.
Speaker 1 (05:54):
Screen wired instant and the other type.
Speaker 2 (05:57):
That's PSP or photostimulable phosphor plates. These are wireless, thin,
flexible like film, which makes positioning often a bit easier
and more comfortable for the patient.
Speaker 1 (06:05):
But they're not instant.
Speaker 2 (06:06):
No, you expose them, take them out of the mouth,
and then you have to run them through a laser scanner.
The scanner reads the stored energy the latent image and
turns it into the digital picture.
Speaker 1 (06:15):
Gotcha, So film like workflow but digital result. Now, why
is digital generally seen as superior? Resolution? Comes up a lot.
Speaker 2 (06:22):
Yeah, two key metrics. First is spatial resolution thinks sharpness
detail measured in line pairs per millimeter lpmm. Digital systems
can hit over twenty lpm.
Speaker 1 (06:33):
And how does that compare?
Speaker 2 (06:35):
Well, it actually beats what the human eye can typically resolve,
which is around twelve fourteen lpm, and it's better than
traditional film too, which is maybe eleven twelve lpmm.
Speaker 1 (06:44):
So potentially more detail capture than we can even see
without help.
Speaker 2 (06:48):
Kind of yeah, which leads to the second metric, grayscale
resolution or contrast measured in bits. Standard computer monitors are
eight bit, meaning they show two hundred and fifty six
shades of great okay, but the sensors can capture way more.
Some systems go up to twelve bits, which is over
four thousand shades of gray.
Speaker 1 (07:06):
Ooh, but wait, if our eyes only distinguish what maybe
sixteen or so shades easily, why capture thousands? Ah?
Speaker 2 (07:12):
That's the magic of digital processing. Having all that raw data,
all those shades means you can use software tools after
taking the shot to manipulate the image, like what kind
of tools? Things like histogram shifting, which lets you lighten
or darken the whole image without re exposing, or histogram stretching,
which changes the contrast range. You can apply sharpening filters,
smoothing filters invert the image to look like a negative,
(07:35):
even use an emboss filter to give it a sort
of three.
Speaker 1 (07:37):
D look so you can pull out details. That might
have been hidden in the initial view.
Speaker 2 (07:41):
Exactly. That's the big advantage. But digital isn't perfect. It
has its own unique errors.
Speaker 1 (07:47):
Right, Like overexposure on ccdcmos.
Speaker 2 (07:50):
Yeah, if you blast it with too much radiation you
get saturation. The very dark areas just bottom out, become
pure black, and you lose all detail there. It's gone.
You can't recover it with software.
Speaker 1 (08:01):
Okay. So overexposure is bad.
Speaker 2 (08:03):
Under exposure that leads to noise, the image looks grainy
or snowy. You lose detail in the lighter areas.
Speaker 1 (08:10):
And the PSP plates have their own special problem, right.
Speaker 2 (08:12):
Something about light, Yes, this is crucial. Unlike film, which
isn't really sensitive to visible light after exposure, PSP plates
are If you leave an exposed PSP plate sitting out
in room light, especially bright light, before.
Speaker 1 (08:26):
You scan it, it gets erased.
Speaker 2 (08:27):
It can. Yeah, the light erases the latent image, So
you need to protect them from light between exposure and scanning,
and also after scanning you have to deliberately expose them
to a bright light source to fully erase them before
you reuse them.
Speaker 1 (08:41):
Okay, handle with care regarding light. Let's move to panoramic imaging.
Chapter seven talks about six interpretive zones.
Speaker 2 (08:48):
What's the idea there, It's just a systematic way to
evaluate a panoramic image. Make sure you don't miss anything
and spot common errors. Zone one is the dentition itself.
The occlusal plane should have that gentle upward curve the
smile line.
Speaker 1 (09:02):
Okay.
Speaker 2 (09:03):
Zone two is the TMJs looking for symmetry, condole centered
roughly equal size. Zone three the mandible's lower border should
be smooth and continuous.
Speaker 1 (09:12):
Got it? Zones four five.
Speaker 2 (09:14):
Zone four is the nose and sinus area. You should
see turbinates, the hard palette shadow above the upper teeth roots.
Zone five involves the spine and ramis. Ideally, the spine
shouldn't be superimposed over the rainnis. Zone six is the
hyoid bone should look like mirror images on both sides,
not smeared across the jaw.
Speaker 1 (09:30):
Okay, So using those zones help spot positioning errors too.
What are the classic panel mistakes? Oh?
Speaker 2 (09:35):
Yeah, patient, too far forward in the machine you get skinny,
blurred front teeth, and classically you see a ghost image
of the spine laid right over the ramis area.
Speaker 1 (09:46):
Okay, too far forward, skinny teeth spawn ghost too far back.
Speaker 2 (09:51):
Then the interior teeth get wide and magnified, kind of
distorted and unreliable. The telltale sign, though, is often a
ghost image of the ramis itself appearing across the other side,
sometimes like a horizontal line dividing the body. In ramis.
You might also see the turbinates looking weirdly spread across
the sinus right and the.
Speaker 1 (10:08):
Chin positioning that's a big one. Chin too low.
Speaker 2 (10:11):
Creates that exaggerated smile line like a deep frown curving down.
It often cuts off the roots of the lower front
teeth and you get the hyoid bone ghosting across the mandible.
Really messes up the diagnostic value.
Speaker 1 (10:23):
Yeah, ruins the whole lower part of the image. What
about if the patient doesn't put their tongue on the
roof of their mouth.
Speaker 2 (10:27):
Ah Yeah, simple instruction fail. You see a big, dark,
radiolucent shadow arching over the roots of the maxillary teeth.
That airspace causes it. Easy to fix with better instructions
next time.
Speaker 1 (10:39):
Okay, let's move into diagnosis now. Chapter two covers recognizing
dental materials amalgam composite crowns. It's usually straightforward, but distinguishing
restorations from carries, especially near the gum line.
Speaker 2 (10:53):
Yes, that brings up the great impostor cervical burnout. It's
a radio lucent area looks dark like decay hay often
seen on the necks of teeth, especially like distal of
mandibular canines or premolars. Sometimes upper molars looks just like
root carries.
Speaker 1 (11:08):
So how do you tell the difference?
Speaker 2 (11:10):
This is critical key takeaway. Cervical burnout is an optical
artifact caused by the shape of the tooth and the
X ray angle. True Carries is actual missing tooth structure.
So if you suspect burnout, take another bite wing, but
change the horizontal angulation.
Speaker 1 (11:24):
Slightly change the angle, and.
Speaker 2 (11:25):
If that dark spot disappears or significantly changes shape on
the second film taken from a different angle, it was
cervical burnout, true Carries will still be there looking pretty
much the same brilliant.
Speaker 1 (11:35):
Okay, change the horizontal angle. Got it. The book also
details anomalies structural.
Speaker 2 (11:40):
Ones, yeah, things like dentinogenesis imperfecta. You see obliterated tiny
pulps and bulbous bell shaped crowns. Amelogenesis imperfecta has various
looks depending on the subtype, but it affects the enamel,
making it thin or poorly mineralized, and torridontism bull teeth,
big pulp chambers, short roots, no properfication.
Speaker 1 (12:03):
Recognizing those patterns is key. What about tooth number and
position issues.
Speaker 2 (12:08):
Well, Messiodins is the most common extra tooth found between
the upper central incisors. Concrescens is when two teeth are
joined only by their cementum. And a crucial measurement is
the follicular space around an unerupted tooth crown right.
Speaker 1 (12:20):
The space should be tubic.
Speaker 2 (12:22):
Exactly on an intraoral film. If it's wider than about
two point five millimeters or three milimeters on a panel,
you start worrying about pathology like a dentigerous cyst.
Speaker 1 (12:30):
Forming okay, And if you find something weird, like an
impacted canine or a foreign object, you need to know
if it's on the cheek side or the tongue side.
Localization rules three.
Speaker 2 (12:38):
Main ones described. The classic is the Solb rule same
lingual opposite bookle. You take two shots, keeping the vertical
angle the same but changing the horizontal tube shift. If
the object moves in the same direction as the tube
shifted it's lingual. If it moves opposite to the tube shift,
it's bookele.
Speaker 1 (12:56):
Slob got it? What are the others?
Speaker 2 (12:59):
The bookle object rule sometimes called Richard's rule. It basically
says the object that is bookele or closer to the
cheek will move in the same direction as the cone
or be itself is moved between the two shots.
Speaker 1 (13:11):
Okay, bookele moves at the cone.
Speaker 2 (13:13):
And the third known object rule or lunglaze rule. This
one feels maybe more intuitive for some. You compare the
movement of your unknown object to the movement of a
known anatomical landmark nearby, like the zygomatic arch, bookele or
maybe the genial tubercules lingual. If your object moves with
a known bookle landmark, it's bookele. If it moves opposite,
it's lingual relative to that landmark.
Speaker 1 (13:35):
Right. Using landmarks as a reference, these rules are like
your diagnostic compass. Let's talk pathology signs from chapter eleven.
Cysts first ten.
Speaker 2 (13:43):
Tittorous cyst is a classic one around the crown of
an impacted tooth. That paraicronal radilucency. A primordial cyst is
interesting because it develops instead of a tooth. It takes
the place where a tooth should have formed, often turns
out to be an okac an odontogenetic, craticist.
Speaker 1 (14:00):
Okay, and lateral periodontal.
Speaker 2 (14:02):
Syst typically found on the side of a root, most
commonly in the mandibular canine premolar region, usually well defined
round or ovlucency.
Speaker 1 (14:10):
Tumors and displays have specific looks too.
Speaker 2 (14:13):
Definitely cemento blastoma. You see this dense radiopaque mass stuck
right to the root apex, but critically it's surrounded by
a thin, even radiolucent line or halo.
Speaker 1 (14:24):
That halo is key fibrous dysplasia.
Speaker 2 (14:26):
That's the one with the classic ground glass or sometimes
orange peel or fingerprint pattern. The bone looks kind of hazy,
trabecular or in distinct.
Speaker 1 (14:33):
And odonogenic mix alma sounds exotic.
Speaker 2 (14:36):
It has a very specific look, usually multilocular, meaning multiple compartments,
but the septa, the lines dividing the compartments are often straight,
thin and angular forming geometric shapes, sometimes described as looking
like a tennis racket or a fish skeleton inside very distinctive.
Speaker 1 (14:51):
Wow, Okay, memorize those patterns. What about signs of aggressive
disease or systemic issues.
Speaker 2 (14:57):
The floating tooth sign is a big red flag. It
looks like the tooth is just suspended in space because
the supporting bone around it has been rapidly destroyed. You
have to figure out why, is it super aggressive periodontal
disease or something more sinister like a malignancy, maybe metastatic cancer.
Urgent investigation needed.
Speaker 1 (15:16):
Scary stuff, any other systemic signs.
Speaker 2 (15:19):
Hyperparathyroidism can cause generalized bone demineralization, loss of the laminadura
that wideline around the tooth root, and sometimes these olytic
lesions called brown tumors. And the book also mentions the
punched out skull lesions you see in multiple myeloma.
Speaker 1 (15:33):
Okay, lots to recognize there. Let's wrap up by revisiting
chapter nine, Radiation, Health and Protection. What's the single best
way to cut patient dose?
Speaker 2 (15:42):
Hands down? Collimation Using a long sixteen inch rectangular bed
is the most effective method. The text states it reduces
the dose by something like three hundred percent to six
hundred percent compared to using even a long round.
Speaker 1 (15:53):
Bed, three to six times less radiation. That's huge, massive.
Speaker 2 (15:58):
In the book notes it was expected to become the
required standard for peri appicles because it's so much more
efficient at reducing unnecessary exposure.
Speaker 1 (16:06):
And machine type matters too.
Speaker 2 (16:07):
Yes, constant potential DC machines are better than the older
AC machines. They give about a twenty percent dose reduction
for the same image quality because they produce a more
consistent effective X ray beam without the lower energy photons
that just add to patient dose without improving the image.
Speaker 1 (16:24):
Better beam quality, less ed dose. What about lead aprons?
Speaker 2 (16:28):
Interestingly, the text mentions pending federal guidelines even back in
two thousand and four, suggesting that patient protective aprons might
eventually be discontinued, especially with digital imaging and rectangular colimation
becoming more standard. The beam is just so focused.
Speaker 1 (16:43):
That's a shift in thinking. Finally, infection control non negotiable.
Speaker 2 (16:47):
Right absolutely, It's federally mandated by OSHA. The key distinction
the book makes is between sterilization killing everything, including tough
bacterial spores like TB, which is required for instruments that
penetrate tissue critical items, and disinfection, which kills most pathogens
but not necessarily all spores.
Speaker 1 (17:04):
And the crucial point for digital sensors.
Speaker 2 (17:06):
You cannot heat sterilize them in an autoclave, they'll be destroyed.
So they require meticulous use of protective barriers and intermediate
level surface disinfection between patients following manufacture instructions is critical.
Speaker 1 (17:18):
Okay, So all this knowledge, anatomy, technique, errors, pathology, safety,
it all comes back to that core idea, doesn't it exactly?
Speaker 2 (17:27):
The eye cannot see what the mind does not know.
If you haven't learned what normal looks like, how errors manifest,
and what the signs of disease are, you just won't
see them on the radiograph, and.
Speaker 1 (17:37):
You'll end up taking more pictures than necessary, increasing dose,
or worse, missing something important.
Speaker 2 (17:43):
Precisely mastering this stuff minimizes retakes and maximizes your diagnostic
ability for every single image.
Speaker 1 (17:50):
All right, let's solidify one of those diagnostic decision points.
Here's a quick scenario for you listening. You take a
bite wing and you see a dark spot, a radio
lousence on the distal surface of a lower first molar
near the gum line. You suspect root carries, but you
remember cervical burnout. To definitively rule out burnout, What specific
(18:11):
change do you make for the next image, and how
will that dark spot look if it is just burnout?
Speaker 2 (18:16):
Okay, the key change is you must alter the horizontal
angulation of the X ray beam for the second bite wing.
Keep the vertical angle the same, but shift the tube
head slightly measily or distally, and the result if that
radiolycent spot essentially disappears or drastically changes shape on the
second image taken with a different horizontal angle, then you've
confirmed it was the artifact cervical burnout, not true decay.
Speaker 1 (18:39):
Confidence confirmed excellent, rule out the artifact. Trust your diagnosis.
Thanks for joining us for this deep dive into the
foundations of oral radiology.
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