PATHOLOGY OF THE TEETH
1. ) Dental caries and pulpitis
2. ) Periapical diseases.
3. ) Periodontal diseases.
4. ) Odontogenic cysts and tumors.
1. Dental caries.
-is progressive destruction of the mineral substances of the tooth by acid,
accompanied by breakdown of organic matrix
etiology of dental caries:
-dental caries is an infectious disease of microbial origin
-in vitro studies have demonstrated a number of microorganisms to be capable
of causing dissolution of enamel and dentine
-particularly the role of streptococcus mutans was shown to be important
-the role of dental plaques- dental plaque is composed of of aggregates of
microbes embedded in organic matrix and food debris- plaque varies in thickness
and composition and if left undisturbed it becomes calcified- to form calculusdeposits of calcified plaques are heaviest on lingual aspects of the lower teeth sharp decrease of pH which occurs in dental plaque favours demineralization of
the tooth surface- clinical consequence is a dental caries
-dental caries is painless in early stages, advanced caries causes discomfort and
toothache
-the disease predominantly affects the crowns of erupted teeth-causing
destruction of enamel and dentine
 -the lesion starts as enamel caries- the earliest detectable lesion is a white
spot lesion or opacity in the enamel
-this is most often seen in areas between adjacent teeth, and near the gingival
margin- the lesion is smooth-opacity is due to superficial demineralization- when
such lesion is examined, it shows a conical area of demineralisation with the apex
towards the amelodentinal junction
-the lesion eventually penetrates the full thickness of the enamel and then
spreads laterally at the amelodentinal junction to affect larger area- enamel is
weakened and ultimately fractures to leave a cavity- this allows bacteria to
penetrate and accelerate the destruction
 -as the lesion progresses to involve dentine, - dentine caries develops
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-enamel is an extracellular matrix and does not contain any living cells, whereas
dentine is penetrated by the cell processes of the odontoblasts that lie on its
pulpal aspect
-once caries begins to affect dentine - the destruction of organic matrix is
accompanied by defensive reaction of the pulp-dentine complex (odontoblasts
produce irregular secondary dentine) and by inflammatory reaction within the
pulp- bacteria invade and extend down the dentinal tubules- focal areas become
distended with masses of bacteria to form liquefaction foci- which may fuse to
form transverse clefts in dentine
-in rapidly progressing caries the protective secondary dentine is breached and
bacteria reach the pulp -with the further advance of destruction- dentine is
broken- direct bacterial infection of the pulp occurs
 -acute pulpitis- the earliest stage of pulpal inflammation is hyperemia and
leukocytic emmigration in the area of pulp underlying the zone of cariesthere is progressive accumulation of leukocytes- which forms microabscesses
-the inflammation spreads to involve the whole pulp, the inflammatory exudate
increases the intrapulpal pressure (pain)- impairing the pulpal circulation
- this is in most instances followed by complete pulp necrosis, with spread of
infection and inflammation into the tissues around the root apex of the tooth
-this leads to formation of apical abscess- these stages of disease are
accompanied by severe pain (due to severe swelling of the tissue) - apical
abscess develops around the apex of tooth - the abscess enlarges and may drain
through the gingiva
-if the abscess is not able to establish drainage through the surface of
the skin or into the oral cavity, acute inflammation continues and spread
diffusely to soft tissues of the floor of mouth - two extremely dangerous
complications may develop: Ludwig's angina and cavernous sinus thrombosis
 Ludwig's angina - presents a swelling of the floor of mouth, tongue and
submandibular region-leads to restricted neck movement, dysphagia, sore
throat, dyspnea and possibly respiratory obstruction secondary to laryngeal
edema
clinically- fever, chills, leukocytosis and elevated sedimentation rate- treatmentwith modern antibiotic therapy, mortality associated with Ludwig angina has
diminished from 60 % to 8 %

cavernous sinus thrombosis- presents as edematous periorbital enlargement
with involvement of eyelids and conjuctiva, clinically- fever. chills tachycardia,
vomiting- pain in eyeball and menigitis- brain abscess may result
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 -chronic hyperplastic pulpitis (pulp polyp)- this is a unique pattern of pulpal
inflammation, this condition occurs in children or young adults- the most
frequently involved teeth are the deciduous molars- which have large pulp
chambers
-although necrosis is the most common sequel of pulpal inflammation, the pulp
may survive, even when there has been gross destruction of the overlying enamel
and dentine- the remaining pulpal tissue proliferates to form granulation tissue
which bulges into the caries cavity as a polyp- the surface may become
epithelialised and the polyp becomes more fibrotic
2. chronic periapical granuloma (chronic apical periodontitis)
-in chronic stage apical abscess is replaced by apical granuloma, that may
transform into periapical dental cyst
-periapical infection- infection may extend from the tooth pulp to the
apical periodontium- resulting in an inflammatory lesion that progresses through
different stages to -periapical granuloma
 -periapical granuloma refers to a mass of chronically inflamed granulation
tissue at the apex of a nonvital tooth characterized by bone resorption, and
mixed inflammatory infiltrate
-formation of periapical inflammatory lesion represents a defensive reaction
secondary to the presence of bacteria in the root canal
-periapical granuloma either may demonstrate acute exacerbation with new
abscess formation or undergoes epithelialization to form cystic structure called
 radicular cyst (periapical dental cyst) -epithelium at the apex of a nonvital
tooth can be stimulated by inflammation to form a true epithelium-lined cyst,
the source for this epithelium are usually rests of Malassez, cyst development
is common,
-periapical cyst represents a fibrous connective tissue wall lined by epithelium
with lumen containing fluid and cellular debris and some inflammatory cells
Treatment: -localized pulp abscess-simple
antibiotics may be sufficient treatment
drainage
and
installation
of
-periapical granuloma and periapical cysts are treated in the same
manner-succesful treatment centers on reduction of activity of bacteria,
nonrestorable teeth must be extracted, followed by curretage of all apical soft
tissue, if the tooth is maintained, root canal therapy can be performed3. Gingivitis and periodontal diseases
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-gingivitis and periodontal diseases constitute a group
inflammatory conditions of the tooth-supporting structures
of
destructive
-inflammation - acute gingivitis, which may be progressive to destructive
periodontitis-both result in an instability, and loss of the tooth
 periodontitis- is an inflammatory disease that affects the supporting
structures of the teeth, such as periodontal ligaments, alveolar bone and
cementum
-with progression, the process leads to the loss of attachment with destruction
of the periodontal ligament and alveolar bone
-it is now believed that periodontitis is caused not by mere presence of dental
plaque, but by change in composition of bacterial flora within the plaque-only few
types of bacteria were shown to be related to p.-itis, such as type of
actinobacillus...
-cause of p.-itis has not been completely delineated, but three possible
hypotheses exist, direct destruction by bacteria or their products, immune
hyper-responsiveness and immune deficiency
4. ODONTOGENIC CYSTS AND TUMORS
1) CYSTS OF THE JAW - are very common- can be developmental or
inflammatory, many of them occur in relation to the teeth- odontogenic cysts,
the other cysts are not related to teeth- non-odontogenic cysts
A) Developmental cysts-two major type can be distinguished : 1) odontogenic gingival cyst of infants (Epstein pearls)- is small cyst arising from epithelial
cell rests in the alveolar mucosa of infants, -these lesions are commonly seen
at birth- are white to yellow nodules
histologically-thin lining of stratified squamous epithelium, keratin fills the cyst
cavity
 odontogenic keratocyst (primordial cyst)- a cyst arising in the tooth-bearing
areas of the jaws, or posterior to third molar, characterized by a thin fibrous
capsule and lining of keratinized squamous epithelium
-the mandible is involved much more frequently than maxilla, about half of
cases occurs at the angle of the mandible, radiographically- unilocular ot
multilocular pattern
-can be associated with Gorlin syndrome (nevoid basal cell carcinoma syndrome)is inherited as autosomal-dominant trait with hgih penetrance, is characterized
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by multiple basal cell carcinomas of the skin, multiple jaw cysts, vertebral
anomalies, epidermal cysts and intracranial calcifications
-locally aggressive growth, recurrence rate 25-30%
histologically: thin fibrous wall, lined by thin epithelial lining composed of
squamous cells with parakeratosis, if inflammed-the wall and fibrous capsule may
be thickened -most keratocysts are isolated lesions, they have marked tendency
to recur
 dentigerous (follicular) cyst -arises from the epithelial residues of the tooth
follicle, associated with failure of eruption of involved tooth, most commonly
located in the lower third molar
-the wall of cyst is formed by the dental follicle-the wall is fibrous, the lining is
of stratified squamous epithelium with mucous metaplasia
-if the unerupted tooth is present in the wall of the cyst, then it is called
dentigerous cyst
 eruption cyst-occurs in the gingiva averlying tooth about to erupt, seen in
children, painless, lined by stratified squamous epithelium
 lateral periodontal cyst- uncommon cyst, mostly located in mandible anterior
to molar region, lined by squamous or columnar epithelium, can erode the bone
 gingival cyst of adults- accounts for 0.5% of jaw cysts, painless slowly
enlarging, mandible more commonly affected,lined by flattened squamous
epithelium
 glandular odontogenic cyst (sialo-odontogenic cyst)- can be multi-or
unilocular, is characterized by papillary luminal surface lined by eosinophilic
cuboidal or ciliated cells, focally with mucin producing cells
2) non-odontogenic-these uncommon cysts of the jaw
are formed without association with teeth, they usually occur in the midline of
the anterior part of the maxilla, the variant include nasopaltine, median palatine,
palatine papilla amd median alveolar cyst
 nasopalatine duct (incisive canal) cyst-is most common of them, slowly
growing cyst -sweeling in the midline of the palate-discharge and pain
histologically: the lining is varialbe, it consists of either ciliated columnar
(respiratory) or squamous epithelium, mucous glands may be present
B) Inflammatory cystsradicular cyst- most common, is the result of the process of reepithelization of
periapical granuloma- chronic inflammatory response initiates proliferation of
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Malassez epithelial nests, and epithelium starts to penetrate the granuloma,
central cystic cavity is formed and lined by squamous cell epithelium
2) The tumors of the jaw
-the jaws are subject to the same range of tumors as occur elswhere in the body
-in addition- dental apparatus may give rise to the odontogenic tumors
-these tumors are rare, and only ameloblastoma is more common
-ameloblastoma- is the most common odontogenic tumor, it accounts for
about 1-2% of all jaw tumors, occurs mainly in 2.-4. decades, most often in the
molar region of the mandible,
microscopically: the tumor is composed of islands and cords of odontogenic
neoplastic epithelium within the fibrous stroma -the epithelium in ameloblastoma
resembles that seen in the tooth germ
-the cells at the periphery of epithelial islands are cuboidal or low columnar and
have their nuclei oriented towards the centre of epithelial cord- reversed
polarity
-many histological patterns may occur, including anastomosing cords and
plexiform patterns, cystic, pseudocystic, and solid regions
-ameloblastoma is not encapsulated, capable of local destruction and invasioncomplete local excision is a good treatment
clinically: locally aggressive, may recur after surgical removal, rare development
of metastasis
-squamous odontogenic tumors- uncommon, arises in the periodontal
ligament, it consists of islands and nests of squamous epithelium in dense
desmoplastic stroma -epithelium is cytologically bland- tumor may grow
aggressively, but does not recur after surgical removal
-adenomatoid odontogenic tumor-arises in younger age group, most
common site is the maxillary canine and incisor region -benign
-the tumor is well circumscribed, composed of bilayered epithelial nests and
duct-like structures, occasionally there are focal deposits of enamel-like
extracellular material or calcification
-calcifying epithelial odontogenic tumor (Pindborg tumor)- rare, form
multilocular masses with variable degree of calcifications and bone expansion
histologically highly variable appearance- giant multinuclear cells, prominent
nuclear polymorphism, but few mitoses
-locally infiltrative - similar aggressiveness as inameloblastoma, low tendency to
progression, no metastasis
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-odontogenic ghost cell tumor (calcifying odontogenic cyst, Gorlin
cyst)- produces painless swelling, majority arise in the mandible, the tumor is
benign
-histologically composed of the cells with abnormal keratinization- with presence
of so called ghost cells-large pale stained cells shadow-like
-ameloblastic fibroma- rare tumor, more comonly seen in children,
composed of stroma that resembles primitive dental pulp- very cellular with
little collagen formation, and benign looking epithelial nests
-benign tumor, it can recur
-odontoma complex and compound- among most common odontogenic
tumors, they are considered to be developmental anomalies- hamartomas
-consists mainly of enamel and dentin, with variable amounts of pulp and
cementum
the compound odontoma- is composed of multiple, small tooth-.like structures
the complex odontoma-consists of complex masses of enamel and dentin, which
bears no anatomic resemblance to a tooth
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