Artificial intelligence shaping dentistry

  • Artificial intelligence refers to the stimulation of human intelligence in machines that are programmed to think like humans and mimic their actions.
  • On the other hand, artificial general intelligence (AGI) is probably what we are thinking of when we hear AI. AGI isn’t quite developed yet. AI, however, is very much present and growing in every industry, from consumer technology to health care

How is AI currently used in dentistry?

In dentistry, AI is being used for different applications. First, AI is currently being used for voice commands, such as with DEXvoice by Simplifeye and DEXIS (software platforms).

Phrases such as “Alexa, show me the bitewings of number 19” will soon be uttered in dental practices around the country.

Through machine learning, MMG Fusion’s chairfill ( software designed to help dental practices fill holes in the schedule) retrieves data from a dentist’s record and analyzes it. Chairfill can find the most profitable dentistry not yet provided, communicate with patients directly, and even book patients appointments. It does all of this without human involvement.

Scientists are already using AI in caries detection. One company utilising AI in this way is Dentistry.ai. Its algorithm is designed to take a large data set of radiographs and recognise patterns within that data. As a result, it hepls practitioners more accurately to identify carious lesions.

The founders of Dentistry.ai predict that AI will be tightly woven into the fabric of how dentistry is done.

The primary llimitationsto AI are insufficient data and inaccurate data. This means that clinicians today should focus on collecting the data now to be able to use it fully in the future. If we can do that, we can continue to provide greater care to our patients.

Source : journal of dental economics

Nanodentistry

Advancement in technology led to its usage in various fields and it helped build new devices that were not possible 10 or 20 years ago and made most of the jobs easier.

Such advancements include application of nanotechnology in dentistry, also known as nanodentistry, allows for treatment possibilities in restorative dentistry, orthodontics and periodontics.

Within restorative dentistry, nanorobots can be used in cavity preparation, restoration, and even dentition renaturalization.

Due to their size, nanobots work at the atomic, cellular, and molecular level to perform major tasks and help dentists in managing complicated cases at the microscopic level with ease and precision.

Bottom-up Approaches :

Local Nanoanaesthesia

A colloidal suspension containing millions of anesthetic dental nanorobots would be used to induce local anaesthesia. Deposited on the gingival tissue, the nanorobots would reach the dentin and move toward the pulp via dentin tubules guided by a nanocomputer under the control of dentist. On reaching pulp, the analgesic robots may close down all sensation in tooth. When the treatment procedure is done, the nanorobots may be ordered to re-establish all sensations and to exit from the tooth

Tooth repositioning :

All the periodontal tissues, namely the gingiva, periodontal ligament, cementum and alveolar bone, may be directed by orthodontic nanorobots leading to Swift and pain-free corrective movements

Nanorobotic dentifrice (Dentifrobots):

Toothpastes or mouthwashes could contain the dentifrobots which would then survey all gingival surfaces regularly.

Dental durability and cosmetics :

Nanostructured composites can be included with sapphire 12 or diamond to reduce their brittleness which are used to enhance the toughness and appearance of teeth.

Diagnosis of oral cancer :

  • Nanoscale cantilevers : elastic beams used to attach with cancer linked molecules
  • Nanopores : small holes that enable DNA passage one strand at a time, this making DNA sequencing highly efficient
  • Nanotubes : carbon rods that can detect affected genes and also localise their location
  • Quantum dots : these glow very brightly in UV light. They attach to proteins associated with cancer cells, this localizing tumours
  • A nanoshell is a tiny bead like structure with superficial metal layers which may imbibe selective wavelengths of radiations and lead to large amounts of heat production. This results in specific devastation of the tumour cells, sparing the normal cells.

Dental nanomaterials – anodentistry as top-down approach :

Nanocomposites :

  • Nanofillers are minute particles, igher proportions can be achieved, and result in distinctive physical, mechanical and optical properties.
  • One nanocomposite system has three different types of fillers : non agglomerated discrete silica nanoparticles, barium glass and prepolymerized filler
  • Advantages – increased hardness, improved flexural strength, decreased polymerization shrinkage, High polish retention

Nanosolution (nanoadhesives) :

  • Nanosolutions are constituted by dispersible nanoparticles, which are then used as a component in bonding agents.
  • Advantages – higher dentin and enamel bond strength, high stress absorption, longer shelf life, durable marginal seal, flouride release

Impression materials :

Traditional vinylpolysiloxanes have incorporated Nanofillers which produce a distinctive material with improved flow, enhanced hydrophilic properties and superior detail precision.

Nano-composite denture teeth :

  • Porcelain teeth are highly wear resistant but are brittle, acrylic on the other hand undergo undue wear. Nanocomposite denture teeth are made of PMMA and homogenously distributed Nanofillers
  • Advantages – excellent polishing ability and stain resistant, superb esthetics, enhanced wear resistance and surface hardness

Dentifrices :

These are mainly made of nanosized hydroxyapatite molecules. They will result in protective shell on tooth surface and may even repair damaged areas. Microbrite dentifrice has microhydrin which breaks down the organic food particles

Prosthetic implants :

Nanotechnology would aid in the development of surfaces with definite topography and chemical composition leading to predicable tissue integration. Tissue differentiation into definite lineage will accurately determine the nature of peri implant tissues. Eg- nanotite, nano-coatef implant

Nano sterilizing solution :

A new sterilizing solution following nanoemulsion concept has been developed by Gandly Enterprises Inc Florida. Nanosized oil droplets attack and destroy the pathogens. Eg – eco tru disinfectant

Dentition replacement therapy (major tooth repair) :

Nanotechnology may utilize genetic engineering, tissue engineering and tissue regeneration initially, followed by growing whole new teeth in vitro and their iinstallation

Nanotechnology will bring enormous changes in the field of dentistry when few challenges such as precise manufacture of nanoscale parts, financing and tactical concerns, social issues have overcome.

Source : journal of international oral health

Types of toothbrushes

Toothbrushes have been in existence since thousands of years and have become an indispensable part of our life. Earlier it used to be in the form of chew stick format but over time, different formats of tooth brushes emerged such as tree twigs, bird feathers and porcupine quills.

Let us know about the different type of toothbrushes available in today’s market

Manual toothbrush

  • The most common form of toothbrush available in our homes is manual toothbrush.
  • Bristles available for this type of toothbrush are soft, medium or hard bristled. Most dentists advice soft bristled brush but other two help in removal of more plaque but that may wear away the enamel if brushed too hard
  • Round or square shaped headed toothbrushes are available but diamond shaped head is more convenient to rach the back and sides of molars
  • Toothbrush handle design includes straight, contra-angle, non-slip grip and flexible types.

Electric toothbrush

  • An electric toothbrush performs rotations of its bristles and cleans hard to reach places. Some even have timers to help you brush more effectively. It has been discovered that compared to a manual brush, the multi-directional power brush might reduce the incidence of gingivitis and plaque.
  • Electric toothbrushes are further divided into three types depending on speed of its movements – standard power toothbrushes

Sonic toothbrush is powered toothbrush that is fast enough to produce a hum in the audible frequency

Ultrasonic toothbrush is a powered toothbrush which is faster than the sonic toothbrush

Interdental toothbrush

  • Also called interproximal brush used for cleaning between teeth and between the wires and dental braces and teeth

Sulcabrush

  • it is used specifically to clean along the gumline adjacent to the teeth.
  • A sulcabrush is ideal for cleaning specific difficult-to-reach areas, such as between crowns, bridgework and crowded teeth.

End-tuft brush

  • It is a small round brush head compromising of Seven tufts of tightly packed soft nylon bristles, trimmed so the bristles in the center can reach deeper into small spaces.

Chewable toothbrush

  • It is a miniature plastic molded toothbrush which can be placed inside the mouth.
  • They are generally used by travellers
  • It is usually available in different flavours such as mint or bubble gum

Ecological toothbrush

  • These are toothbrushes made out of biodegradable substances such as wooden handles, bristles of bamboo or pig bristles and replaceable heads

source : http://www.malidds.com

The Olfactory System

THE OLFACTORY SYSTEM

Landmarks: midline nasal cavitytemporal lobe, anterior corpus callosumfrontal lobecribriform plate and olfactory epithelium.

  • The cribriform plate separates the cranial vault from the nasal cavity.
  • Fracture to the cribriform plate (or more commonly to the ethmoid air cells posterolateral to the cribriform plate) is a common cause of rhinorrhea — cerebrospinal fluid leak from the nasal cavity.

OLFACTORY BULB & TRACT

  • Lie underneath the frontal lobe.
    • The olfactory bulb is often distinguished as the main olfactory bulb because the majority of vertebrates also have an accessory olfactory system. However, the role and existence of the accessory olfactory system (aka vomeronasal system) in humans is disputed.

THE OLFACTORY NERVE, BULB, & TRACT: ESSENTIALS

  • Bipolar primary olfactory neuron: dendrites project to the olfactory epithelial surface and the centrally-mediated axon (the olfactory nerve) extends through the cribriform plate to innervate the olfactory bulb.
  • Within the olfactory bulb, lie bipolar secondary olfactory cells, which connect with the olfactory nerve in the inferior olfactory bulb and also send axons down the olfactory tract: at the posterior end of the olfactory tract, lies the olfactory trigone.
  • CN 1, the olfactory nerve, refers to the primary olfactory neuron/nerve, only. ## The olfactory bulb and tract are extensions of the cerebrum, itself.
  • The olfactory system bypasses the thalamus as it projects to the cerebral cortex, which is unique. Auditory, visual, somatosensory, and gustatory sensory pathways all relay within the thalamus prior to synapsing in the cerebral cortex.
  • The olfactory tract divides into a medial olfactory stria, which innervates the medial olfactory area in the subcallosal (aka septal) region, and a lateral olfactory stria, which innervates the primary olfactory cortex in the basal frontal and anteromedial temporal lobes.  Olfactory impulses also extend across the anterior commissure to the opposite side of the cerebrum.

THE OLFACTORY NERVE, BULB, & TRACT: CONNECTIONS

  • Cilia from the apical dendrite interact with the mucus layer of the olfactory epithelial surface.

Key constituents of the olfactory epithelium include:

  • The sustentacular cells, which are olfactory supporting cells.
  • The basal cells, which renew the primary olfactory neurons and sustentacular cells.
  • The Bowman’s glands, which secrete a serous, watery odor dissolvent.
  • CN 1 comprises an unmyelinated nerve bundle to interact with bipolar secondary olfactory neurons.
  • Two principal forms of secondary olfactory neuron exist: tufted cells and mitral cells.  Less notable interneurons (eg, periglomerular and granule cells) also exist within the olfactory bulb.
  • The glomerular layer refers to the layer of spherical glomeruli which encompass the interaction between dendrites from the secondary olfactory neurons and primary olfactory axons within the inferior olfactory bulb.
  • The secondary olfactory neurons project axons that travel either directly down the olfactory tract to synapse in the olfactory cortex or first to the anterior olfactory nucleus, which projects its axons down the olfactory tract to the olfactory cortex.

The Ear: Anatomy & Physiology

EAR CANALS: external, middle, and inner.

THE EXTERNAL EAR CANAL

  • Extends through the tympanic portion of the temporal bone, just in front of the mastoid process.

THE MIDDLE EAR CANAL

  • Lies mostly within the tympanic portion of the temporal bone.
  • From lateral to medial, it contains three ossicles: the malleus, incus, and stapes, which are Latin for: “hammer,” “anvil,” and “stirrup,” respectively. # The stapes abuts the oval window.
  • When sound is transmitted through the ossicles, the stapes pushes the oval window into the inner ear canal.
  • The eustachian tube extends from the middle ear into the nasopharynx, which allows your middle ears to equilibrate with the atmospheric pressure in your nasopharynx when you swallow.
  • Two important muscles exist within the middle ear canal: the tensor tympani, which is innervated by the trigeminal nerve and which acts on the tympanic membrane, and the stapedius muscle, which is innervated by the facial nerve and which acts on the stapes.

THE INNER EAR CANAL

  • Lies within the petrous portion of the temporal bone.
    • The semicircular canals, which lie in superior-lateral position and serve vestibular function.
    • The cochlea, which is shaped like a snail’s shell, and lies in anterior-inferior position and serves auditory function.
    • The vestibule, which lies in between the cochlea and semicircular canals — it transmits sound waves from the oval window to the cochlea and show that it contains the otolith organs, which provide vestibular cues.

THE COCHLEA

Integral for the detection of sound.

  • 3 Ducts:
    • The cochlear duct (scala media).
    • Vestibular duct (scala vestibuli) (which is continuous with the vestibule).
    • Tympanic duct (scala tympani), which ends in the round window (aka the secondary tympanic membrane).
  • Membranes:
    • Reissner’s membrane separates the vestibular and cochlear ducts.
    • The Basilar membrane separates the cochlear and tympanic ducts.
  • Fluids:
    • The vestibular and tympanic ducts are filled with perilymphatic fluid, which is high in Na+ and low in K+ (like extracellular fluid).
    • The cochlear duct is filled with endolymphatic fluid, which is high in K+ and low in Na+ (like intracellular fluid).

Ménière’s syndrome (bouts of vertigo, low-frequency hearing loss, and ear fullness ) is thought to be due to pathologically elevated endolymphatic sodium concentration, so it is commonly treated with salt-wasting diuretic medications.

PHYSIOLOGY OF SOUND DETECTION

  • When a sound wave enters the external ear canal, it vibrates the tympanic membrane.
  • The tympanic membrane, then, transmits the wave through the ossicles: the malleus, incus, and stapes, and the stapes strikes the oval window.
  • When the oval window vibrates, a fluid wave passes through the vestibule and the vestibular duct.
    • The vestibular and tympanic ducts connect at the apex of the cochlea (aka the helicotrema).
    • The sound waves passes across the apex of the cochlea into the tympanic duct, through the tympanic duct, and pushes the round window into the air-filled middle ear canal.

In this process, the auditory sensory organ, the organ of Corti, which lies along the basilar membrane, is activated for sound detection.

  • High-frequency sounds activate hair cells at the base of the cochlea (near the oval and round windows) whereas low-frequency sounds activate hair cells at the apex of the cochlea.
  • The basilar membrane is thinnest at its base and widest at its apex.

THE MAJOR VESTIBULAR COMPONENTS OF THE EAR: THE OTOLITH ORGANS AND THE SEMICIRCULAR CANALS.

  • Within the vestibule, lie the saccule, which detects vertical movement (ie, gravity), and the utricle, which detects horizontal (forward/backward) movement.
  • The macula (the neuroepithelial sensory detection region) of the saccule is principally vertically oriented and its attached hair cells are horizontally oriented to detect vertical movement, whereas the macula of the utricle is principally horizontally oriented and its attached hair cells are vertically oriented to detect horizontal movement.

THE SEMICIRCULAR CANALS: HORIZONTAL, POSTERIOR, AND ANTERIOR.

  • These three semicircular canals lie perpendicular to one another and detect rotational acceleration, which we address in the next tutorial.

Retina Histology

ANATOMICAL ORIENTATION

  • The vitreous chamber lies internal to the retina.
  • The choroid lies external to the retina.

THE TEN LAYERS

1. The pigmented layer

  • Retinal retinal pigmented epithelium (commonly abbreviated RPE).
    • It is involved in photoreceptor metabolism and that it comprises which captures light not picked up by the photoreceptors.

2. The photoreceptor cell layer of rods and cones

  • Photoreceptor cells:
  • Involved in light capture and PHOTOTRANSDUCTION; the phototransduction cascade occurs here, which transforms light into neural signal. The photoreceptor cell segments are metabolically dependent upon the pigmented epithelium for photoreceptor regeneration and waste disposal.
  • Divisions
    • Outer segment
    • Inner segment.

3. External limiting membrane

4. Outer nuclear layer

  • Photoreceptor cell bodies.
    • Cones have a large outer, conical segment; they provide high-resolution color vision.
    • Rods have a small, narrow cylindrical outer segment; they provide low-resolution dim-light (“night”) vision. Rods outnumber cones by roughly 15:1.

Central vs Peripheral Vision

  • Cones predominate in central vision (within the fovea)
  • Rods predominate in peripheral vision (outside of the macula).

5. Outer plexiform layer

  • It comprises a thin synaptic zone; we’ll draw these synapses momentarily.

6. Inner nuclear layer

  • It comprises retinal interneuronal cell bodies.

This layer specifically comprises:

  • BIPOLAR CELLS, which, as we see have two poles, so they can pass forward electrical signal from the photoreceptor cells to the ganglion cells (drawn soon).
  • HORIZONTAL and AMACRINE CELLS, which enhance visual contrast.

Visual Contrast vs Illumination for Visual Perception

  • It is well recognized that the visual system relies more on visual contrast than the overall level of illumination for visual perception. The visual system attends to the borders between light and dark areas or color differences more so than light intensity.
    • As long as we can read the page of a book comfortably, we perceive the words on it just the same in varying levels of illumination; it is the contrast of the ink from the page that makes the largest impression in our mind.
  • MÜLLER GLIAL CELLS extend across the retina: their proximal endings form the inner limiting membrane (as we’ll soon see) and their distal processes help form the external limiting membrane.

7. Inner plexiform layer

  • It comprises a thick synaptic zone.

8. Ganglion cell layer

  • It comprises ganglion cell bodies.
    • The ganglion cell dendrites help form the inner plexiform layer, and the axons form the nerve fiber layer.

9. Nerve fiber layer

  • It comprises axons of the ganglion cells, which are unmyelinated.

10. Inner limiting membrane

  • It forms from the basal lamina of Müller glial cells.

CONSOLIDATION OF LIGHT CAPTURE & PROCESSING

  • Light passes through the retina and is captured by the photoreceptor cell segments where the phototransduction cascade occurs, which converts light to neural signal.
  • Neural signal signal is passed back through the retina: to the photoreceptor nuclei to the bipolar cells, the ganglion cells, and our along the ganglion cell axons (the nerve fiber layer), which are unmyelinated so as to NOT impeded the light from passing through the retina to the photoreceptor cell layer.

THE 10 LAYERS OF THE RETINA

From outside to inside:

  • Sclera
  • Choroid
  • The pigmented epithelium
  • Photoreceptor cell layer of rods and cones
  • External limiting membrane
  • Outer nuclear layer
  • Outer plexiform layer
  • Inner nuclear layer
  • Inner plexiform layer
  • Ganglion cell layer
  • Nerve fiber layer
  • Inner limiting membrane

Eye Anatomy

The eye contains three layers. From outer to inner, they are:

  • The fibrous coat (aka corneoscleral coat)
    • Cornea
    • Sclera.
  • Uvea (aka uveal tract)
    • Iris
    • Ciliary body
    • Choroid (the majority of the uvea)
  • Neural layer: The Retina

THE OUTER LAYER: THE CORNEOSCLERAL COAT

  • Anteriorly, lies the CORNEA which has a pronounced curvature and is transparent to allow for the passage of light.
  • Where the cornea ends, the outer layer becomes the SCLERA, which is opaque, so it blocks the transmission of light.
    • The portion of the sclera we can see is the “white of the eye”; conjunctiva covers it.
  • Further posterior, six EXTRAOCULAR MUSCLES insert into the sclera.

THE BICONVEX LENS

  • It’s transparent and serves to focus a target on the retina, specifically on the area of maximal visual acuity: the fovea centralis of the macula.

THE MIDDLE LAYER: THE UVEA

  • In front of the lens, lies the pigmented IRIS, which forms an adjustable diaphragm to funnel light through the pupil.
    • The PUPIL is the open region within the center of the iris.
  • Posterior to the iris, label the CILIARY BODY.
    • The iridocorneal angle is where the corneal meets the iris; this is also the sceralcorneal junction: the site of the canal of Schlemm, which is fundamental to aqueous humor reabsorption.
  • Posterior to it, lies the CHOROID, which is a thin highly vascular layer sandwiched between the sclera and retina.
    • It nourishes the retina and removes heat produced during phototransduction, which is the process wherein the photoreceptors transform light into neural signal.

CILIARY BODY FUNCTIONS

  • Anchors suspensory ligaments, collectively called ZONULE, which stretch the lens and alter its refractive power.
  • Produces AQUEOUS HUMOR, which is a low- protein, aqueous (ie, watery) fluid.

THE VITREOUS CHAMBER

  • Contains vitreous humor (aka vitreous body).
    • Like aqueous humor, vitreous humor is primarily water, but the presence of glycosaminoglycans and collagen within this substance gives it its gel-like composition, which helps maintain the eye’s shape.

THE NEURAL LAYER: THE RETINA

  • Lies internal to the choroid.
  • Transitions into optic nerve when it exits the eye, posteriorly, at the lamina cribrosa: the retinal fibers become myelinated posterior to the lamina cribrosa.
    • They are unmyelinated within the retina to avoid blocking the passage of light through the retinal layers.
  • The central retinal artery and vein pierce the optic nerve and run through its center.

ANATOMICAL FEATURES OF THE RETINA

  • The optic nerve head.
  • The macula, the area of highest visual acuity (in the center of it, lies the fovea centralis).
  • The ora serrata is the anterior limit of the retina.
    • It’s an important anatomical landmark because it delineates the anterior limit of the retina and choroid, and the posterior limit of the ciliary body.

Anatomical details of the Retina:

  • On the nasal side, lies the optic disc (aka the optic nerve head). It comprises:
    • The neuroretinal rim (which is pink).
    • The optic cup, a pale hole through which the central retinal vessels emanate.
  • In the center of the macula lies the fovea centralis.

THE MENINGEAL LAYERS

  • The sclera becomes:
    • Dura mater (aka dural sheath)
    • Arachnoid mater (aka arachnoid sheath)
  • The pia mater is an extension of the optic nerve.
  • The subarachnoid space lies between the arachnoid mater and pia mater.
    • It allows increased intracranial pressure to translate along the optic nerve and impair its axoplasmic transport, which results in optic disc swelling: called disc edema or, rather, papilledema when it occurs in the setting of increased intracranial pressure.

SUPERFICIAL STRUCTURES OF THE EYE

  • The palpebra is the eyelid.
  • The palpebral fissure is the distance between upper and lower eyelids.
  • The corneal limbus separates the cornea from the sclera.
  • The sclera forms the “white of the eye”.
  • The iris is pigmented.
    • In its center is the pupil.
  • At the lateral extreme, lies the lateral canthus (aka lateral commissure).
  • At the medial extreme, lies the medial canthus (aka medial commissure).
  • The lacrimal caruncle lies at the medial corner of the eye; it produces whitish, oily fluid – “sleep in the eye”.

THE IRIS MUSCLES

  • Iris sphincter muscles are circumferentially-arranged.
    • They are parasympathetically-innervated muscles, which constrict pupil size in bright light.
  • Iris dilator muscles are radially-arranged.
    • They are sympathetically-innervated muscles, which widen pupil size in low light.