Dentistry Notes PDF

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Summary

Dental Pulp - Dental pulp makes a total volume of 0, although the pulp of the molars 4X larger than those of the incisors. Dental pulp is a loose CT which is kept in a pulp chamber with two root canals which have an opening to allow lymphatics, vessels, and nerves to enter. The purpose of pulp is to...

Description

Dental Pulp -

Dental pulp makes a total volume of 0.38mL, although the pulp of the molars 4X larger than those of the incisors. Dental pulp is a loose CT which is kept in a pulp chamber with two root canals which have an opening to allow lymphatics, vessels, and nerves to enter. The purpose of pulp is to allow for sensation of sensitivity and pain as well as to carry vessels and lymphatics which nourish the tooth and protect the tooth from foreign infections.

Anatomical Regions of Pulp - The coronal pulp occupies the crown and contains 6 surfaces: occlusal, mesial, distal, buccal, lingual, and floor. It contains pulp horns which correspond to the cusps of the crown. Often decreases in size with old age due to dentinogensis - The radicular pulp runs from the cervix to the apex via the root canal. Will also diminish with age due to dentinogenesis.

Histological zones - Odontoblastic layer - Cell-free zone - Cell rich zone - Pulp core

Cells in the Pulp - Odontoblasts in the odontoblastic layer; they make dentin - Fibroblasts which make the matrix, fibres, and ground substance of the pulp – found in the cellrich zone - Undifferentiated mesenchymal cells which may either turn into odontoblasts or fibroblasts. - T-Lymphocytes, macrophages, and dendritic antigen-presenting cells. Matrix - Made of Type I (60%) and Type III (reticular) collagen (40%). - Contains glycosaminoglycans: hyaluronic acid (60%), dermatan sulphate (20%), chondroitin sulphate (12%), and heparin sulphate (8%). - Contains proteoglycans and glycoproteins.

Vascular Supply to the Tooth - Oxygenated blood supply of the arteries arises from the common carotid  external carotid  inferior and superior alveolar arteries  alveolar arteries  pulpal arterioles - 20mL-60mL/min to 100grams of teeth Innervation of the Teeth - Highly innervated by axons and nociceptors - The axons reach the odontoblasts or go to the cell-free zone

Hydrodynamic Theory of Dentin Hypersensitivity The hydrodynamic theory of dentin hypersensitivity states that the change in dentinal fluid from pressure, heat, cold, and other stimuli will cause a depolarization of the neurons attached to the odontoblasts. When heat is detected by the fluid, it causes the dentinal tubules to expand thus causing the dentinal fluid to move down into the pulp. Cold causes the dentinal tubule to constrict thus causing the cold water to flow outwards.

Age related changes to pulp - Pulp gets smaller with age due to creation of secondary dentin - Pulp becomes more fibrous - Pulp becomes less innervated with nerves and vessels - Pulp stones may occur. - “wear and tear”; as we age, the more our teeth have been through and the more trauma it has been affected with. Odontoblasts, thus, create a secondary dentin which projects the pulp and the roots of the tooth. Pulp Stones - Sites of calcification - They can be detected by radiographs; on the molars the bite-wings will aid in detecting pulp stones. - True denticles are pulp stones that are calcification of dentin with some tubules - False denticles are pulp stones of bone with some cells in it Clinical Considerations: - Dead pulp or necrosis to the pulp causes black or darkley shaded teeth - Progressiveness of the necrosis can affect the dentin which gives it that colour

Dentin -

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Dentin is located right under the crown It is pale yellow in colour and contributes to the color of teeth Contains parallel tubules known as dentinal tubules which contain dentinal fluid. Dentin, dentinal fluid, and the matrix of dentin are formed by the fixed cells known as odontoblasts. The odontoblasts on the inner aspect of dentin, right under the mineralised dentin. The dentinal tubules contains processes of odontoblasts. Dentin is stronger than bone and cementum, but softer than enamel. Dentin is not as hard or as stiff as enamel, but it does have greater compressive strength and can withstand something squishing against it; thus, dentin supports enam el because without dentin enamel would just be brittle and shatter. Dentin, by volume, is composed 70% of inorganic (calcium hydroxyapatite), 20% inorganic (collagen by 90% and proteoglycans), and 10% water

Dentinal Tubules - Run parallel in a “sigmoidal” or curved way - As they reach the dentino-enamel, curvatures of the dentinal fluids become less pronounced - At the pulp-dentin junction, tubules are 2.5 micrometers wide, but at the dentino-enamel junction they become 1 micrometers wide. - Dentinal tubules can branch off, usually occurs profusely at the dentinoenamel junction - Between dentinal tubules are intertubular dentin (matrix) - In the dentinal tubules, peritubular dentin is laid down and begins to shrink the gap of the dentinal tubule. Peritubular dentin does not contain any collagen matrix and is more mineralised than intertbular dentin. - As we know, near the denitnoenamel junction, the intratubular dentin calcifies to make a much narrower tubule and the opposite for the pulp-dentin junction. If the intratubular dentin continues to calcify on both junctions the tubule will be very narrow and thus sensation of that tooth may be close to diminished. - Within the tubules are odontoblastic processes, afferent axons, and dentinal fluid. Different types of Dentin Primary dentin - Comprises the bulk of dentin o Mantle dentin which is slightly less mineralised and contains tubules; near the dentinoenamel junction o Circumpulpal dentin, as in the name, is dentin that surrounds the pulp chamber Secondary dentin - Develops after root formation is complete

Tertiary dentin - Reparitive dentin; makes dentin after damage or trauma to cells. Dentinogenesis - In the pulp, specifically the cell-rich zone are undifferentiated mesenchymal cells - These cells go under mitotic activity and either become odontoblasts (make dentin) or ameloblasts (make enamel). - In early stages of dentinogensis, you will see von korff’s fibres which are type III collagen fibres that sit near the mantle dentin - Odontoblasts produce matrix vesicle which become foci for desposition of inorganic formation -

Oral Mucosa -

Lining of the mouth It is a wet, specialised area It protects the mouth from microorganisms and abrasions It secretes mucous and saliva by gland embedded in them It allows for sensation to temperature, pressure, taste, swallowing, gagging, and retching. Oral mucosa is an epithelium that contains an underlying connective tissue and lamina propria.

Outer vestibule: Includes the cheeks and the lips Oral cavity proper: Gingiva, alveolar mucosa, tongue, roof which is comprised of the hard and soft palate and the floor which is comprised of the tongue and base of mouth. Types of Mucosa 1. Masticatory mucosa: 25%; gingiva, hard palate 2. Lining mucosa: 60%; comprises of alveolar mucosa, upper lip, buccal mucosa, labial mucosa, soft palate, ventral tongue. 3. Specialized mucosa: 15%; comprises of the dorsal tongue Components of Mucosa - Generally speaking, all mucosa has an epithelium layer of stratified squamous epithelium - They all contain a lamina propria within the connective tissue layer. The connective tissue layer in some mucosa may contain sebaceous glands with hair follicles; near the lip, cheeks, etc.. - Some mucosa contains a submucosal layer which contain minor salivary glands. Components of the gingival mucosa - Stratified squamous keratinising epithelium, including all masticatory mucosa - The lamina propria is directly attach to the alveolar bone: mucoperiosteum. All lining mucosa is stratified squamous non-keratinising epithelium.

Within the epithelium you will find melanocytes which give mucosa their pink colour, Langerhans cells which are macrophages, and merkel cells which act as nerve cells. The Tongue - The tongue is a muscular organ in the mouth which contains many papillae on its dorsal surface. - These papillae contain many taste buds within them - There are 4 types of papillae: fungiform, circumvallate, foliate, and filiform. Filiform papillae - Do not contain any taste buds - Play a role in gripping food - Most abundant; found in the anterior 2/3 of the dorsal tongue. Fungiform papillae - Found within filiform - Found on the anterior aspect of dorsal tongue - May have taste buds

Foliate papillae - Found on the lateral aspects of the tongue - Ususally not found in humans Circumvallate papillae - Contian taste buds - Larger - Found on the posterior aspect of the dorsal side of tongue

Major Junctions of Oral Mucosa Dentinogingival Junction - Where the gingiva and the tooth meet - The gingiva that attaches to the tooth has some parts to it. The main part that is attached to the enamel/cementum of the tooth is called the junctional epithelium - This junctional epithelium contains the lamina propria and hemidesmosomes to attach itself to the basal lamina and to the tooth itself. - When a dentist is preforming an oral examination, they will usually use their probe to measure how deep your gingival sulcus is. In a healthy person, 0.5-3mm is a safe gingival sulcus depth; anything higher than these numbers is considered pathological and that is why it is so important to floss. - The dentinogingival junction serves a great purpose to hold the tooth in place and keep it from falling out of its’ socket. Mucogingival Junction - Junction between the alveolar mucosa and the gingiva. - The alveolar mucosa is non-keratinising while the gingiva is keratinising. - Clinically, the alveolar mucosa looks like a darker pink while the gingiva looks lighter pink. - Alveolar mucosa is made of loose connective tissue with lamina propria and many elstic fibres - Gingival mucosa contains lamina propria and coarse collagen fibres that attach to the periosteum of the alveolar bone.

Mucocutaneous junction - Where oral mucosa meets with skin - May contain hair follicles and sebaceous glands - The vermillion are the lips; keratinising epithelium with thin layer of epithelium but many capillary loops in surface of connective tissue - Contains no salivary glands

Salivary Glands - Exocrine glands - Secrete substances into the mouth via ducts - 3 major glands - Many minor salivary glands that contribute to 10% of salivary outflow Parotid Gland - Gland found near the muscles of the face by the ear - Duct is located in the alveolar mucosa above the second molar on the maxillary level. - Composed strictly of serous acinar glands - Secrete saliva with many enzymes such as hydrolase which aid with the breakdown of food - Surrounding connective tissue contains many plasma cells which secrete antibodies with the saliva to fight of foreign substances Submandibular salivary gland - Made of tubular-acinar glands with both serous and mucous cells - 90% is serous cells; 10% is mucousa cells with serous deminlunues - Serous cells secrete amylase. - Serous Demilune screte lysozyme that hydrolyses bacterial walls. Sublingual salivary gland - Made of tubular-acinar gland with both serous and mucosa cells - Predomintly mucous cells - Serous cells are strictly present as deminlunes

Taste How we perceive smell - In infancy, we can interpret right away what taste good and what tastes bad - If something is sweet and nice, infants tend to smile or chap their lips - If something is bitter and bad, infants tend to frown or grimace - Taste and smell cells are known as chemoreceptors – they detect senses by chemicals that cause a change. - Taste is 75% smell Why do we taste? - Taste is something that allows us and our bodies to become conscious of what we are eating and if it is potentially dangerous to our bodies. - Usually eating something good means it is good for us and vise-versa, but this is not always the case - Some things that taste and smell good tend to be poisonous to our bodies Smell -

Odours and gasses are inhaled by the nose or mouth and are collected by olfactory cells. These olfactory cells call up memories in the brain, specifically the amygdala, and determine what is good and what is bad Females have a keener sense of smell Both nostrils can perceive slightly diferent smells – aids with precision Loss of smell is known as anosmia

Taste -

Perceived by taste buds in our papillae on our tongue, except for filiform papillae 75% smell is taste 5 diferent senses of taste

Types of senses for taste: - Sweet: Triggered by sugars such as fructose and glucose - Salty: Sensation to salts and foods with Na - Umami: Triggered by glutamate or monosodium glutamate. - Bitter: Triggered by alkaloids; our tastebuds are the most sensitive to bitter foods. - Sour: Triggered by accumulation of H+ ions; low pH

Lingual Papillae - Majority of the taste buds are found within the lingual papillae. - Taste bud are also found on the palate, pharynx, and epiglottis. - Filiform papillae are papillae on the anterior 2/3 of the tongue. They do not contain any taste buds, rather play a role in gripping food - Fungiform papillae are the second most abundant papillae in the tongue and are found amongst the fungiform papillae. They contain taste buds on the superior aspect of it - Foliate papillae are found on the lateral aspects of the tongue. Taste buds are found on the lateral aspect of the papilla. - Circumvallate papillae are found on the posterior aspect of the dorsal tongue. They are the largest and most rounded. Taste buds are found on the lateral aspect of the papilla.

Taste Buds and their Anatomy

The taste bud is composed of epithelium and many cells within it. Type I cell are supporting cells; Type II are gustatory cells for sweet, umami, bitter and sometimes salty; Type III is for sour; Type IV are basal cells that replenish and change the gustatory cells every 2 weeks. Taste chemicals cause membrane changes to the gustatory cells which cause an action potential to sensory nerves: cranial nerves (7- facial; 9 – glossopharyngeal; 10 – vague nerve)

Taste Transduction - Umami, sweet, and bitter taste intiate G-Couples protein - Molecules such as glutamate and monosodium glutamate will attach to the T1R1 and T1R3 recepots of an umami gustatory cell which will cause G-protein activation and increase of intracellular calcium ions to cause depolarization. - Molecules such as glucose will attach to T1R2 and T1R3 receptors and cause a membrane change which will activtate G-proteins and increase intracellular calcium to cause depolarization. - Molecules such as alkaloid metal will bind to TR2 proteins and cause a membrane change which will activtate G-proteins and increase intracellular calcium to cause depolarization. - Salty ions such as Na+ will enter via sodium ion channels to increase intracellular Ca2+. Neural Pathways for Taste - Anterior 2/3 is supplied by CNVII (facial nerve) - Posterior 1/3 is supplied by CNIX (glossopharyngeal nerve) - Pharynx, larynx, epiglottis, and palate are supplied by CNX (vagus nerve) - These nerves join together at the brain stem. As they move further along the brain they join with the nerves for smell to detect flavour and go towards the temporal lobe which is associated with memories; thus, smell and taste can bring up memories. Taste Disturbances – Clinical highlights - Chlorohexidine: Found in moth wash; persistent taste of bitterness; loss of salty taste - Sodium lauryl sulphate: detergent aspect of toothpaste; loss of sweet and salty taste - Doxycycline: Anosmia - Tetracycline: Metallic taste - Metronidazol: Taste disturbance.

Tooth Morphology Ev e r yt oo t hha sdi ffe r e n tc h a r a c t e r i s t i c st ha ta l l o wi tt of unc t i o npr ope r l ya nda l l o wu st oe a t ,s hr e d ,a n d t e a rf ood .

I nc i s o r s The incisors play a role in shearing food, or breaking off food. Maxillary Central Incisor Loo ki n ga tt hepi c t u r e ,f r om t hepa l a t a lvi e w, y ouc a ns e et h eme s i a l a nddi s t a lma r gi na lr i dg e ss ur r oundi ngt hel i n gua lf os s a .I nf e r i ort o t hef os s ai st hec i ngul um. Fr om t hel a bi a lvi e w, t hec ut t i n ge dg ei s kno wna st hel a bi oi nc i s a le dg e .Youc a na l s os e et h a tt heont he me s i a le ndoft hel a bi a li nc i s a le dg ei smuc hs ha r pe rt ha nt hed i s t a l , a st hi st oot hi sa ne xa mpl eofa nma xi l l a r yl e f tc e nt r a li nc i s or .The t oot hi sc on v e xont hel a bi a ls ur f a c ea ndc onc a v eont h epa l a t a l s ur f a c e . C MMR

DMR LF LIE

Max i l l ar yLa t e r alI nc i s o r

Si mi l a ri nl oo kst ot hema xi l l a r yc e nt r a li nc i s or .Rounde ddi s t oi nc i s a l a n g l ewh i l et heme s i oi nc i s a le d g ei ss ha r p,buti ti snota se vi de nta si t i si nt h ema x i l l a r yc e nt r a li nc i s or . Thi st o ot h ’ sr ooti smu c hmor el on g e r a n dl e s spr opor t i ona t et ot h es i z eoft hec r o wnt ha nt hec e nt r a li n c i s or a n dt her ootc u r v e st o wa r dst hedi s t a le nd.

Mandi bul arCe nt r alI nc i s o r

Func t i on:Cut t i ngf o od Ov e r al lappe ar anc e :Sma l l ,s ha r pi nc i s i v ee dg e . Li ngua l :Re l a t i v e l ys moot ha ndha spoor l yd e v e l ope dc i n gul uma ndma r gi na lr i dg e s . I nc i s al :Ne wl ye r upt e dh a s3ma me l ons , butbe c o me ss ha r po v e r t i me . Me s i al : Di s t al : Labi al :Comv e x Root :Sa mes i z er oota sma xi l l a r yc e nt r a li nc i s or , buta pe xi smor ebl un t . Me s i odi s t a l c ompr e s s i onoft her oot Func t i on:Cut t i ngf ood Li ngua l :Unde v e l o pe dma r g i n a lr i dg e s ,bu tmor ede v e l ope dt h a nma ndi bul a rc e nt r a l i nc i s or . I nc i s al :Ne wl ye r upt e dha s3ma me l on st he nbe c ome ss ha r p;s l i ght l yl o n ge ri nc i s i v e e dg et ha nma nd i bul a rc e nt r a li n c s i o r .Sha r pe rme s i oi nc i s a le dg et ha ndi s t oi nc i s a le dg e . Me s i al :Me s i a ls i deofc r o wni ss l i gh t l yl on g e r .

Cani ne s Tr a ns i t i ona lt e e t hbe t we e nt hei nc i s or sa ndt hepr e mol a r s .Onl yt oot hi nt hede nt i t i onwi t hon ec us p. Te a r i n gf o odi st he i rf u nc t i o n. Max i l l ar yCa ni ne Pal a t al :Bul k y , we l lde v e l op e dc i n gul u m I nc i s a l :Ones h a r pl y poi nt e dc us p. Me s i al :Le s sde e pe rs l op eofc us pt ha ndi s t a l Di s t al :De e pe rs l op eofc us p Labi al :Con v e x Ro ot :Longr oo t

Mandi bul arCani ne

Pr e mol ar s

Li ngual :Conc a v e ;l e s sd e v e l ope dma r gi na lr i d g e sa ndc i n gul um i n c omp a r i s ont oma xi l l a r y . I nc i s al :Si ng l e ,poi nt e dc us p;no ta ss ha r pa sma xi l l a r y . Me s i al :Fl a t t e ne dr ootwi t hs l i g h tgr oo v e Di s t a l :Fl a t t e ne dr ootwi t hs l i g h tgr oo v e Labi al :Con v e x Root :Lo n gs t r on gr oot ;c a nbebi fidi ns omec a s e s . Th ec r o wnoft hema n di bul a rc a ni n ei sn a r r o we rwhi c hma ke si tl oo k l a r g e ri npr opor t i on

Pl a yr ol e si nt e a r i n gf ood .Bi c us pi d . Fi r s tMaxi l l ar yPr e mol ar

Occlusal fissure which empahsies the cusps on the buccal and palatal ends. Contains 2 roots; buccal and palatal. The buccal cusp is larger than the palatal cusp.

Se c ondMax i l l ar yPr e mo l ar

Occlusal fissure which emphasies two cusps: palatal and buccal. Both cusps are similar in size. Contains one root.

Fi r s tMandi bul arPr e mol ar

Contains a mesio-distal occlusal fissure. 2 cusps, the buccal one is larger. Single conical root.

Se c ondMandi bul arPr e mo l ar Si n gl ec oni c a lr oot . Oc c l u s a ls ur f a c ec ont a i nsa me s i o di s t a lfis s ur e .Se p e r a t e st het woc us p swhi c h a r et hebuc c a la ndl i n g ua lc us p.Thebuc c a lc us pi s l a r g e ra ndt hel i n gua lc us pc a nbedi vi d e di nt o2 c us ps :me s i o l i n gua la nddi s t ol i n gua lc us ps .

Fi r s t ,s e c ond,andt hi r dmaxi l l ar ymol ar s - Al l3ha v e3r oo t s( 2buc c a la nd1pa l a t a l ) - Ont h efir s tmol a r , t hepa l a t li sl on g e ra n ds t r on g e r . - The2buc c a lr oo t sa r...