Developmental Developmental disorders or anomaliesdisorders or anomalies

A failure or disturbance that A failure or disturbance that occurs during the developmental occurs during the developmental processes causing a lack, excess processes causing a lack, excess

or deformity of a body part.or deformity of a body part.

Inherited or Congenital DisordersInherited or Congenital Disorders

Inherited – different from Inherited – different from developmental in that they are developmental in that they are caused by an abnormality in the caused by an abnormality in the genetic makeup - transmitted from genetic makeup - transmitted from parent to offspringparent to offspring

Congenital – present at birth Congenital – present at birth – Can be inherited or Can be inherited or

developmental….congenital developmental….congenital abnormalities usually have an unknown abnormalities usually have an unknown cause.cause.

Developmental Soft Tissue Developmental Soft Tissue AbnormalitiesAbnormalities

Ankyloglossia – “tongue-tied” – Ankyloglossia – “tongue-tied” – complete or partial fusion of the complete or partial fusion of the lingual frenum to the floor of the lingual frenum to the floor of the mouth or lingual attached gingivamouth or lingual attached gingiva– May have problems with speechMay have problems with speech– May need frenectomyMay need frenectomy

Commissural Lip PitsCommissural Lip Pits

Epithelium-lined blind tracts located Epithelium-lined blind tracts located at the corners of the mouthat the corners of the mouth

Congenital lip pit – midline of the Congenital lip pit – midline of the vermilion border of the lipvermilion border of the lip

Lingual ThyroidLingual Thyroid

Ectopic lingual thyroid nodule – a Ectopic lingual thyroid nodule – a mass of thyroid tissue located on the mass of thyroid tissue located on the tongue away from the normal tongue away from the normal anatomic location of the thyroid anatomic location of the thyroid gland.gland.

Appears as a smooth nodular mass Appears as a smooth nodular mass at the base of the tongue posterior to at the base of the tongue posterior to the circumvallate papillae on or near the circumvallate papillae on or near the midline.the midline.

Developmental CystsDevelopmental Cysts

A cyst is an abnormal, A cyst is an abnormal, pathologicpathologic sac or sac or cavity lined by epithelium and enclosed in cavity lined by epithelium and enclosed in a connective tissue capsulea connective tissue capsule

The most common cyst observed in the The most common cyst observed in the oral cavity is caused by pulpal oral cavity is caused by pulpal inflammation and is called the radicular inflammation and is called the radicular cystcyst– The residual cyst is a radicular cyst that The residual cyst is a radicular cyst that

remains after extraction of the offending toothremains after extraction of the offending tooth

Developmental CystsDevelopmental Cysts

Odontogenic – related to tooth Odontogenic – related to tooth development development

Nonodontogenic – not related to Nonodontogenic – not related to tooth developmenttooth development

Intraosseous – occur within boneIntraosseous – occur within bone Extraosseous – occur in soft tissue Extraosseous – occur in soft tissue

(out of bone)(out of bone)

Odontogenic CystsOdontogenic Cysts Dentigerous cyst – forms Dentigerous cyst – forms

around the crown of an around the crown of an unerupted or developing unerupted or developing tooth.tooth.

This radiograph features This radiograph features the typical example of a the typical example of a dentigerous cyst. The well-dentigerous cyst. The well-defined radiolucency defined radiolucency surrounding the crown of surrounding the crown of the unerupted molar. Cysts the unerupted molar. Cysts of this size are generally of this size are generally asymptomatic and are asymptomatic and are discovered on routine discovered on routine radiographic examinationradiographic examination

Primordial CystPrimordial Cyst

The difference between primordial and The difference between primordial and dentigerous cysts is illustrated well in this dentigerous cysts is illustrated well in this case. A dentigerous cyst is associated with case. A dentigerous cyst is associated with the unerupted lower molar while the large the unerupted lower molar while the large well-defined radiolucency extending from well-defined radiolucency extending from the midline to the opposite lower first the midline to the opposite lower first molar proved to be a primordial cyst on molar proved to be a primordial cyst on biopsy examination. biopsy examination.

Primordial cysts do not involve crowns of Primordial cysts do not involve crowns of unerupted teeth.unerupted teeth.

Primordial CystPrimordial Cyst

Primordial CystPrimordial Cyst

This is a typical This is a typical example of the example of the primordial cyst primordial cyst occurring in the third occurring in the third molar area. No tooth molar area. No tooth had developed so we had developed so we can assume the cyst can assume the cyst originated from either originated from either the enamel organ the enamel organ prior to calcification or prior to calcification or from rests of the from rests of the dental lamina.dental lamina.

Odontogenic KeratocystOdontogenic Keratocyst

Pre-OperativePre-Operative This large odontogenic This large odontogenic

keratocyst involving the keratocyst involving the angle and ramus (#37) angle and ramus (#37) was curetted only to was curetted only to "recur" two years later as a "recur" two years later as a lesion high in the ramus lesion high in the ramus (#38) (#38)

Post-OperativePost-Operative Because of the tendency to Because of the tendency to

recur, all patients should recur, all patients should be kept on long-term be kept on long-term radiographic and clinical radiographic and clinical observationobservation

Calcifying Odontogenic CystCalcifying Odontogenic Cyst

The calcifying odontogenic The calcifying odontogenic cyst is less common than cyst is less common than other odontogenic cysts other odontogenic cysts but displays interesting but displays interesting radiographic and radiographic and histopathologic features. It histopathologic features. It may or may not be may or may not be associated with an associated with an unerupted tooth and unerupted tooth and possesses considerable possesses considerable growth potential so that growth potential so that many examples are large many examples are large and somewhat destructive. and somewhat destructive. Any area of the jaw may be Any area of the jaw may be involved.involved.

Calcifying Odontogenic CystCalcifying Odontogenic Cyst

"Ghost Cells""Ghost Cells" These illustrations show These illustrations show

the typical morphologic the typical morphologic pattern of the calcifying pattern of the calcifying odontogenic cyst. An odontogenic cyst. An odontogenic epithelial odontogenic epithelial membrane lines it with membrane lines it with columnar basal cells and columnar basal cells and areas of stellate reticulum. areas of stellate reticulum. There are numerous There are numerous keratin masses that are keratin masses that are described as “ghost cells” . described as “ghost cells” . Dystrophic calcification is Dystrophic calcification is prominent and even prominent and even melanin granules can be melanin granules can be seen seen

Lateral Periodontal CystLateral Periodontal Cyst

The lateral periodontal cyst The lateral periodontal cyst is generally small and well is generally small and well demarcated. It occurs most demarcated. It occurs most frequently in the premolar frequently in the premolar region and is adjacent to region and is adjacent to vitalvital teeth. teeth.

Radiolucencies are Radiolucencies are generally ovoid. generally ovoid.

Here are typical examples:Here are typical examples:

Gingival CystGingival Cyst

This is a good illustration of This is a good illustration of a small slightly bluish a small slightly bluish gingival cyst on the gingival cyst on the mandibular gingiva mandibular gingiva between the lateral incisor between the lateral incisor and cuspid. Gingival cysts and cuspid. Gingival cysts differ from lateral differ from lateral periodontal cysts only by periodontal cysts only by the fact that no significant the fact that no significant radiographic findings are radiographic findings are present in association with present in association with the gingival cyst.the gingival cyst.

Nasopalatine Canal CystNasopalatine Canal Cyst Arise from remnants of the Arise from remnants of the

nasopalatine duct are divided into nasopalatine duct are divided into two varieties: incisive canal type two varieties: incisive canal type and those originating in the and those originating in the papilla palatina. Almost all papilla palatina. Almost all nasopalatine duct cysts occur nasopalatine duct cysts occur within the incisive canal and are within the incisive canal and are intraosseous. They may occur at intraosseous. They may occur at any level between the nasal and any level between the nasal and the oral cavity and are always the oral cavity and are always radiolucent. Cysts of the papilla radiolucent. Cysts of the papilla palatina show no radiographic palatina show no radiographic changes because they are entirely changes because they are entirely within soft tissue.within soft tissue.

This incisive canal cyst is This incisive canal cyst is relatively small but of typical relatively small but of typical location and shape. It has a location and shape. It has a somewhat teardrop shape and somewhat teardrop shape and shows a well-demarcated border. shows a well-demarcated border.

Median Palatal CystMedian Palatal Cyst Median palatal cysts occur at the Median palatal cysts occur at the

midline of the palate posterior to midline of the palate posterior to the incisive canal and are thought the incisive canal and are thought to originate from remnants of to originate from remnants of epithelium remaining after fusion epithelium remaining after fusion of the palatine processes of the of the palatine processes of the maxilla.maxilla.

This radiograph is from a 43 year-This radiograph is from a 43 year-old female who presented with old female who presented with swelling of the midline of the swelling of the midline of the palate for two weeks. The palate for two weeks. The radiograph displays an ovoid radiograph displays an ovoid radiolucency at the midline that radiolucency at the midline that extends quite a distance extends quite a distance posteriorly. Note the nasal posteriorly. Note the nasal septum that is clearly visible. This septum that is clearly visible. This lesion must be differentiated from lesion must be differentiated from the incisive canal cyst and from the incisive canal cyst and from cysts of inflammatory origin cysts of inflammatory origin associated with adjacent teeth. At associated with adjacent teeth. At surgery it was found that this surgery it was found that this lesion did not involve the incisive lesion did not involve the incisive canal and that teeth were vital.canal and that teeth were vital.

““Globulomaxillary” CystGlobulomaxillary” Cyst

Often misdiagnosed as a Often misdiagnosed as a globulomaxillary cyst when in reality globulomaxillary cyst when in reality it is a periapical cyst.it is a periapical cyst.

Lymphoepithelial CystLymphoepithelial Cyst Branchial Cleft CystBranchial Cleft Cyst There is some controversy as There is some controversy as

to the exact origin of this cyst to the exact origin of this cyst that occurs at various levels that occurs at various levels in the lateral neck. Some in the lateral neck. Some believe the lesion arises from believe the lesion arises from remnants of pharyngeal remnants of pharyngeal pouches or branchial arches pouches or branchial arches while others think the lesion while others think the lesion originates from cystic originates from cystic alteration of salivary gland alteration of salivary gland type epithelium often found type epithelium often found within lymph nodes of the within lymph nodes of the neck.neck.

This large branchial cleft cyst This large branchial cleft cyst was moveable, asymptomatic was moveable, asymptomatic and slightly fluctuant.and slightly fluctuant.

Thyroglossal Duct CystThyroglossal Duct Cyst

This asymptomatic swelling This asymptomatic swelling near the midline is a good near the midline is a good example of the thyroglossal example of the thyroglossal duct cyst which is an duct cyst which is an epithelial lined structure epithelial lined structure originating from remnants of originating from remnants of the thyroglossal duct. the thyroglossal duct. The thyroid gland originates The thyroid gland originates from the area of the foramen from the area of the foramen cecum at the base of the cecum at the base of the tongue. The thyroid tissues tongue. The thyroid tissues then migrate to programmed then migrate to programmed location. Remnants of location. Remnants of epithelium remain along this epithelium remain along this tract and these may become tract and these may become cystic or even tumorous.cystic or even tumorous.

Static Bone CavityStatic Bone Cavity Static Bone CavityStatic Bone Cavity

Developmental mandibular lingual Developmental mandibular lingual salivary gland depression (static salivary gland depression (static bone cavity, lingual salivary gland bone cavity, lingual salivary gland depression, and Stafne bone depression, and Stafne bone cavity) represent cortical cavity) represent cortical depressions or defects on the depressions or defects on the lingual aspect of the posterior lingual aspect of the posterior body of the mandible. body of the mandible. These are often bilateral, are These are often bilateral, are asymptomatic and are discovered asymptomatic and are discovered on routine radiographic on routine radiographic examination.examination.

In most cases the radiolucency is In most cases the radiolucency is in continuity with the inferior in continuity with the inferior border of the mandible and is border of the mandible and is below the mandibular canal.below the mandibular canal.

Developmental Dental Developmental Dental Abnormalities Abnormalities

Anodontia - congenital lack of teethAnodontia - congenital lack of teeth Hypodontia - lack of one or more teethHypodontia - lack of one or more teeth Microdontia – smaller (“peg lateral”)Microdontia – smaller (“peg lateral”) Macrodontia – largerMacrodontia – larger Supernumerary- extra tooth …usually smaller Supernumerary- extra tooth …usually smaller

(mesiodens, distomolar)(mesiodens, distomolar)

*familial tendency*familial tendency

Developmental Dental Developmental Dental AbnormalitiesAbnormalities

GeminationGemination FusionFusion Ectopic CuspEctopic Cusp ConcresenceConcresence DilacerationDilaceration Enamel PearlEnamel Pearl TaurodontTaurodont Dens in DenteDens in Dente Dens EvaginatusDens Evaginatus

Abnormalities in the shape of teethAbnormalities in the shape of teeth

Gemination-a single tooth bud Gemination-a single tooth bud divides and results in the incomplete divides and results in the incomplete formation of two teethformation of two teeth

FusionFusion

Union of two normally separated Union of two normally separated adjacent tooth germs.adjacent tooth germs.

More abnormalities in the shape of More abnormalities in the shape of teethteeth

Concrescence - two adjacent teeth Concrescence - two adjacent teeth are united by cementum onlyare united by cementum only

Dilaceration - abnormal root Dilaceration - abnormal root morphologymorphology

Enamel Pearl - small enamel Enamel Pearl - small enamel projection located on a root surface…projection located on a root surface…thought to occur as a result of the thought to occur as a result of the abnormal displacement of abnormal displacement of ameloblasts during tooth formation.ameloblasts during tooth formation.

ConcrescenceConcrescence

Ectopic CuspEctopic Cusp

Talon Cusp - a Talon Cusp - a supernumerary supernumerary cusp which arises cusp which arises from the cingulum from the cingulum portion of an portion of an incisor and extends incisor and extends to the incisal edge to the incisal edge as a prominent as a prominent projection of projection of enamel. enamel.

TaurodontTaurodont A malformed A malformed

multirooted tooth multirooted tooth characterized by an characterized by an altered crown-to-root altered crown-to-root ratio; the crown being ratio; the crown being of normal length, the of normal length, the roots being roots being abnormally short and abnormally short and the pulp chamber the pulp chamber being abnormally being abnormally large.large.

DilacerationDilaceration

Enamel PearlEnamel Pearl

Dens in DenteDens in Dente

"A tooth within a tooth“…a malformation "A tooth within a tooth“…a malformation caused by an invagination of the crown caused by an invagination of the crown before it is calcified.before it is calcified.

Dens EvaginatusDens Evaginatus

A developmental A developmental anomaly in which a anomaly in which a focal area of the focal area of the crown projects crown projects outward and produces outward and produces what appears as an what appears as an extra cusp or an extra cusp or an abnormal shape to abnormal shape to existing cuspal existing cuspal arrangements arrangements (e.g.,talon cusp)(e.g.,talon cusp)

Primarily premolar*usually bilateral…conical, tuberculated projection from the central fissure of the occlusal surface …can interfere with tooth eruption causing malalignment…often in individuals of Mongolian origin

Abnormalities of tooth structureAbnormalities of tooth structure

Enamel hypoplasia-incomplete or Enamel hypoplasia-incomplete or defective formation of enamel, defective formation of enamel, resulting in the alteration of tooth resulting in the alteration of tooth form or colorform or color

Results from a disturbance of or Results from a disturbance of or damage to ameloblasts during damage to ameloblasts during enamel matrix formationenamel matrix formation

Enamel HypoplasiaEnamel HypoplasiaA defect in tooth enamel that results in less quantity of A defect in tooth enamel that results in less quantity of

enamel than normally formedenamel than normally formed

*pits, grooves, lines or larger areas of missing enamel surface  - reduction in enamel thickness  - possible occlusal distortion, aesthetic problems, sensitivity --  yellowish or brownish discoloration…may be localized or present on numerous teeth and all or part of the surfaces of each affected tooth may be involved

Regional OdontodysplasiaRegional Odontodysplasia A developmental A developmental

disturbance of several disturbance of several adjacent teeth in adjacent teeth in which the enamel and which the enamel and dentin are thin and dentin are thin and irregular and fail to irregular and fail to adequately mineralize; adequately mineralize; surrounding soft tissue surrounding soft tissue may be hyperplastic may be hyperplastic and contain focal and contain focal accumulations of accumulations of spherical calcifications spherical calcifications and odontogenic rests.and odontogenic rests.

“GhostTeeth”

Abnormalities of tooth eruptionAbnormalities of tooth eruption

Impacted teethImpacted teeth

Ankylosed TeethAnkylosed Teeth

Roots are “fused” to the alveolar Roots are “fused” to the alveolar bonebone

Especially common with retained Especially common with retained deciduous molars deciduous molars