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1Developmental & Hereditary Conditions

Having a good grasp of oral pathologies and understanding of disease etiologies can make a world of a difference in how efficiently a dentist can identify and monitor oral diseases. We start off our discussion with learning about developmental and hereditary conditions — conditions that may not necessarily be a result of choices we make during our lives as is seen in a number of other diseases of the oral cavity.

•Cleft Lip - an opening or split between the medial nasal process and maxillary process, embryological structures that should normally fuse together

Must know: Can present as unilateral (seen in 80% of cases) or bilateral (seen in 20% of cases)

-Cleft palate is similar to cleft lip, however this defines a lack of fusion between the palatal shelf embryological structures

Prevalence: Very rare, with fewer than 20,000 US cases per year

Treatment: Surgery restores normal function, speech therapy may be helpful

Figure 1.01 Cleft lip

• Fordyce Granules - ectopic sebaceous glands found on the vermillion border of the lips or around the oral cavity

Must know: Often most prominent around puberty, these granules appear as yellow-white papules that may be hyperplastic or nodular

Prevalence: Common, occurs in 70-80% of adults

Treatment: Completely benign, no treatment necessary

Figure 1.02 Fordyce granules

•Fissured Tongue - deep and prominent grooves and fissures across the tongue surface

Must know: benign condition

-Melkersson-Rosenthal Syndrome (MRS) is a rare neurological disorder that includes a fissured tongue, granulomatous cheilitis, and facial paralysis as main characteristics

Prevalence: Common, affects 2-5% of US population

Treatment: None

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Figure 1.03 Fissured tongue

•Geographic Tongue - aka erythema migrans, loss of papillae resulting in red patches that migrate over time (like the Pangea continental drift)

Must know: aka benign migratory glossitis and erythema migrans

-Look for a characteristic white ringed lesion surrounding the red patches

Prevalence: Very common with more than 3 million US cases per year

Treatment: None if asymptomatic, topical corticosteroid if symptomatic

Figure 1.04 Geographic tongue

•Leukoedema - white or white/gray swollen fluid lesion of buccal or labial oral mucosa

Must know: the lesion dissipates when tissue is stretched, as a result of the edematous quality of the lesion

Prevalence: Somewhat rare; mostly seen among black men

Treatment: Completely benign, no treatment necessary

Figure 1.05 Leukoedema

•Lingual Thyroid - mass of thyroid tissue at midline base of tongue

Must know: located along embryonic path of embryonic descent; can be found between foramen cecum of tongue and just past the larynx

-If found past the foramen cecum, the condition is known as a thyroglossal duct cyst, and may be visible on the skin surface

Prevalence: Very rare, reported incidence of 1 in 100,000

Treatment: Surgical methods include excision or autotransplantation into muscle; non-surgical methods include hormonal therapy or radioactive ablation

Figure 1.06 Lingual thyroid

INBDE ORAL PATHOLOGY NOTES

•Lip Pits - pits and fistulas that occur near lip commissures or midline

Must know: Van der Woude Syndrome defines a condition in which the patient presents cleft lip/palate as well as lip pits

Prevalence: Very rare, with incidence of about 1 in 75,000 to 1 in 100,000

Treatment: Usually doesn’t require treatment, but surgical excision may be necessary for more severe cases

Figure 1.08 Lip pits

Still discussing developmental conditions, we now shift our attention to angiomas, or benign tumors that consist of small blood or lymph vessels. Angiomas can be present on the skin surface or inside the oral cavity. Surface angiomas include cherry angioma, or a small red mole that forms from accumulated capillaries and vessels, and hemangioma, a bright red birthmark that appears at birth that is made up of extra blood vessels in the skin.

Figure 1.09 Hemangioma vs cherry angioma

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The oral angioma to know in detail is as follows:

•Oral Lymphangioma - congenital abnormal proliferation of lymphatic vessels on the tongue

Must know:

-Referred to as cystic hygroma when occurs in the neck (more common than oral lymphangioma)

-A syndrome involving lymphangioma is

Sturge-Weber Syndrome, in which angiomas form on the leptomeninges and skin along the trigeminal nerve

Prevalence: Very rare, 1-2/1000 newborns

Treatment: Surgical excision, radiation therapy, or steroid administration are common treatments

Figure 1.10 Oral lymphangioma

Figure 1.11 Cystic hygroma

Another category of developmental conditions to know for the INBDE include exostoses (or tori) which are incidences of excessive cortical bone growth. Exostoses are named primarily based on where they occur, such as buccal exostosis, or toris mandibularis, a bony overgrowth on the lingual aspect of the mandible.

INBDE ORAL PATHOLOGY NOTES

Figure 1.12 Buccal exostosis and torus palatinus

We transition our discussion of developmental conditions to learning about different types of cysts, which are abnormal, usually noncancerous growths filled with liquid, air or other substances. Make sure to know the following conditions!

•Branchial Cyst - cyst within lymph node of the neck that ‘branches’ out from branchial cleft

Must know: also known as cleft sinus

Prevalence: Most common congenital cause of neck mass; exact incidence is unknown

Treatment: Either surgical removal or drainage of fluid

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-Dermoid cysts can contain structures such as hair, fluid, teeth, or skin glands, and have a very doughy consistency

Prevalence: Common, mostly found in children ages 5 and younger

Treatment: Surgical removal

Figure 1.14 Dermoid cyst

•Globulomaxillary Lesion - a cyst appearing between a maxillary lateral incisor and the adjacent canine

Must know: appears as inverted pearshaped radiolucency

-Can cause roots of adjacent teeth to diverge

-Not a diagnosis, and not considered a distinct, classifiable entity

Prevalence: N/A

Treatment: Surgical removal

Figure 1.13 Branchial cyst

•Dermoid Cyst - mass of tissue collecting under the skin that usually appear at birth

Must know: depending on whether the cyst forms above the mylohyoid bone or below, it will be on the floor of the mouth (above) or in the upper neck (below)

Figure 1.15 Globulomaxillary Lesion

•Nasopalatine Cyst - a nonodontogenic developmental cyst

Must know: appears as a heart-shaped radiolucency in the nasopalatine canal

Figure 1.16 Nasopalatine cyst

•Oral Lymphoepithelial Cyst - cyst within lymphoid tissue of oral mucosa

Must know: the palatine and lingual tonsils are common regions for these cysts which appear white or yellowish in color

Prevalence: Rare, usually occurs in adults

Treatment: Surgical removal

Figure 1.17 Oral lymphoepithelial cyst

Finally, we can wrap up our discussion of developmental conditions with learning about two important bone defects.

•Stafne Bone Defect - depression of mandible on the lingual surface

Must know: appears as oval shaped radiolucency in posterior mandible beneath the mandibular canal

Figure 1.18 Stafne Bone Defect

•Traumatic Bone Cyst - an asymptomatic non epithelial lined cavity of the jaw

Must know: appears as a large radiolucency scalloped around roots

-May also be referred to as a simple bone cyst or an idiopathic bone cavity

Prevalence: Rare, mainly diagnosed in young adults; usually associated with jaw trauma

Treatment: Vary from none required to surgical intervention

Figure 1.19 Traumatic Bone Defect

That completes developmental conditions for the INBDE! Let’s now move onto hereditary conditions to learn about their inheritance, and some high-yield information about them.

INBDE ORAL PATHOLOGY NOTES

•Amelogenesis Imperfecta - disorder of tooth development leading to small, discolored, misshapen teeth

Must know: Characterized by abnormal enamel formation (think: ENAMELogensis imperfecta), while dentin and pulp are normal

Inheritance pattern: Autosomal dominant, recessive, or X-linked

Treatment: Full coverage crowns for aesthetics

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•Dentinogenesis Imperfecta - disorder of tooth development affecting primary and permanent dentition, leading to small, discolored, misshapen teeth

Must know: Characterized by abnormal dentin formation, resulting in short roots, bell-shaped and bulbous crowns, and obliterated pulps

-Patients with DI have blue sclera (whites of the eyes)

-Can be associated with osteogenesis imperfecta

Inheritance pattern: Autosomal dominant

Treatment: Full coverage crowns for aesthetics

Figure 1.20 Amelogenesis Imperfecta

•Cleidocranial Dysplasia - fragile bones and teeth, collarbones (clavicles) may be absent

Must know: Dental abnormalities such as delayed loss of primary teeth, delayed appearance of secondary teeth, misshapen teeth, or supernumerary teeth are observed

-Fun fact, Stranger Things star, Gaten Matarazzo “Dustin Henderson” was born with CCD!

Inheritance pattern: Autosomal dominant

Treatment: Reconstructive surgery,

Figure 1.21 Cleidocranial dysplasia

Figure 1.22 Dentinogenesis Imperfecta

•Dentin Dysplasia - disorder of tooth development leading to small, discolored, misshapen teeth

Must know: Characterized by abnormal dentin, resulting in chevron pulps and short roots

-Has Type I (poor root development) and Type II (poor crown development)

Inheritance pattern: Autosomal dominant

Treatment: Not good candidates for restoration, due to both chevron pulps and short roots

INBDE ORAL PATHOLOGY NOTES

Figure 1.23 Dentin dysplasia

•Ectodermal Dysplasia - abnormal development of ectodermal structures such as teeth, mucosal membranes, nails, & hair

Must know: dental manifestations include hypodontia, anodontia, and heat intolerance

Inheritance pattern: X-linked recessive

Treatment: Dental restorative procedures

Figure 1.24 Ectodermal dysplasia

•Epidermolysis Bullosa - defines a group of rare diseases that cause blistering skin

Must know: Mechanical fragility and blistering lead to eventual dental decay due to difficult oral hygiene maintenance

Inheritance pattern: Autosomal dominant or recessive

Treatment: Topical aids for blisters

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Figure 1.25 Epidermolysis Bullosa

•Hereditary Hemorrhagic Telangiectasia - abnormal formation of capillaries on skin, mucosa, and viscera

Must know: Also known as Olser-Weber- Rendu Syndrome

-Telangiectasia (spider veins) are dilated or broken blood vessels near skin or mucosa membranes

-Iron deficiency is a common consequence

-Epistaxis, or nosebleeds, are the most common manifestations of HHT

Think: TIE

Inheritance pattern: Autosomal dominant

Treatment: Bevacizumab (Avastin)

Figure 1.26 HHT

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INBDE ORAL PATHOLOGY NOTES

•Osteopetrosis - disorder in which bones become overly dense, which causes them to brittle and fracture easily

Must know: Also called AlbergsSchonberg disease or marble bone disease

Inheritance pattern: Autosomal dominant or recessive

Treatment: Surgery for severe functional deformities

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•White Sponge Nevus - asymptomatic thick and spongey white patches of tissue that cannot be wiped off

Must know: Commonly found in buccal mucosa

Inheritance pattern: Autosomal dominant

Treatment: None, no serious complications

Figure 1.27 Osteopetrosis

•Regional Odontodysplasia - development anomaly impacting enamel, dentin, and cementum components of teeth

Must know: Termed “ghost teeth” this condition results in quadrants of teeth to exhibit short roots, enlarged pulp chambers, and open apical foramen

-The thin enamel and dentin layers result in a faint, fuzzy image of the teeth when x-rayed, hence the name “ghost teeth”

Inheritance pattern: Unknown

Treatment: Extraction of affected teeth

Figure 1.28 Dentin dysplasia

Figure 1.29 White sponge nevus

We wrap up this first section by distinguishing between tooth fusion and gemination, which have been alluded to throughout our general discussion of different conditions. Fusion involves the merging of two buds into one tooth, resulting in the tooth count to be one less tooth than normal. Gemination, on the other hand, results when one root buds into two crowns, giving us a normal tooth count.

2 Mucosal Lesions

We now transition to more targeted discussions of conditions of the oral cavity, and will start with mucosal lesions. Mucosal lesions describe chemical and physical injury to the mucosal membranes of the mouth, and can vary widely in their severity. This section will focus on five categories of mucosal lesions: reactive, infectious, immunologic diseases, premalignant, and malignant.

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INBDE ORAL PATHOLOGY NOTES

Reactive Mucosal Lesions

Reactive lesions are hyper-plastic tissues that form as a result of a repair response. Let’s learn some high-yield information about assorted reactive mucosal lesions!

•Amalgam Tattoo - gray/blue/black discoloration on oral mucosal membranes

Must know: This common and benign lesion is often mistaken for melanoma, and the radiopaque particles can be viewed on radiographs

Figure 2.01 Amalgam tattoo

•Chemical Burn - a whiteish sloughing appearance on mucosal membranes as a result of chemical reactivity

Must know: Common compounds that cause chemical burns include hydrogen peroxide, aspirin, silver nitrate, and phenol

Figure 2.02 Chemical burn

•Dentifrice-Associated Sloughing - sloughing of mucosal membranes due to sodium lauryl sulfate, a common surfactant in toothpastes and mouthwashes

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Must know: to treat, suggest non-SLS brands such as Sensodyne, Tom’s of Maine, etc

Figure 2.03 Dentifrice-associated sloughing

•Hairy Tongue - tongue appears dark and furry due to buildup of dead skin cells on filiform papillae

Must know: poor oral hygiene, certain medications or antibiotics, tobacco use, or radiation treatment of head/neck are all potential causes of this condition

Figure 2.04 Hairy tongue

•Linea Alba - a fibrous white line in the buccal mucosa

Must know: linea alba is a type of focal hyperkeratosis that forms as a result of chronic friction on mucosa

Figure 2.05 Linea alba

•Melanotic Macule - benign hyperpigmentation in the mucosal membrane

Must know: this is essentially just a freckle of the mucosa

-Peutz-Jeghers Syndrome (PJS) is a condition that puts patients at an increased risk of developing certain cancers, with colorectal cancers being the most common. A feature of PJS is freckling, often around the lips and mouth

-Think: Pigmented lips/mouth and Jejunal polyps

Figure 2.06 Melanotic macule

•Nicotine Stomatitis - reaction seen on the palate caused by extreme heat from tobacco smoking

Must know: Also known as “smoker’s palate” this condition presents red dots scattered on the palate, which are

Figure 2.07 Nicotine stomatitis

•Smoking-Associated Melanosis - increased tissue pigmentation due to irritation from tobacco smoke

Must know: Tobacco chemicals can stimulate melanocytes, which results in diffuse brown macules that are typically seen in anterior gingiva

-This condition is reversible if tobacco smoking is ceased

Figure 2.08 Smoking-associated melanosis

•Submucosal Hemorrhage - extravascular lesions that do not blanch — or blood that has escaped the vessels into tissues and thus blood pressure cannot be altered

Must know: these hemorrhages are