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1 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Chapter 5 Developmental Disorders.

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1 1 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Chapter 5 Developmental Disorders

2 2 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.  Outline  Embryonic Development of the Face, Oral Cavity, and Teeth  Developmental Soft Tissue Abnormalities  Developmental Cysts  Developmental Abnormalities of Teeth

3 3 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Developmental Disorders  (pg. 156)  A failure during the process of cell division and differentiation into various tissues and structures  Some may be identified clinically, by radiographic examination, biopsy, or histologic examination.

4 4 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Developmental Disorders (cont.)  (pg. 156)  Inherited disorder  Caused by an abnormality in genetic makeup  Congenital disorder  Present at birth May be inherited or developmental May be inherited or developmental  The cause of most congenital abnormalities is unknown.

5 5 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Embryonic Development of the Face, Oral Cavity, and Teeth  Face  Oral and Nasal Cavities  Teeth

6 6 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Face  (pgs )  During the third week, ectoderm infolds to form the stomodeum, the primitive oral cavity.  The frontal process is above and the first branchial arch is below.  The first branchial arch divides into two maxillary processes and the mandibular process.

7 7 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Face (cont.)

8 8 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Face (cont.)  Two pits develop on the frontal process.  They divide the frontal process into three parts. The median nasal process The median nasal process The right lateral nasal process The right lateral nasal process The left lateral nasal process The left lateral nasal process  The median nasal process grows downward between the maxillary processes to form the globular process. This will form the philtrum. This will form the philtrum.

9 9 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Oral and Nasal Cavities  (pg. 157)  Premaxilla  Forms from the globular process  Lateral palatine processes  Form from the maxillary process  The lateral palatine processes fuse with the premaxilla, creating a Y-shaped pattern.  The body of the tongue develops from the first branchial arch.  The base of the tongue forms from the second and third branchial arches.

10 10 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Teeth  (pgs )  Odontogenesis  Takes place in about the fifth week of life  Involves ectoderm and ectomesenchyme  Begins with formation of a band of ectoderm in each jaw called the primary dental lamina  Ten small knoblike proliferations develop on the primary dental lamina in each jaw. Each extends into underlying mesenchyme. Each extends into underlying mesenchyme.

11 11 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Teeth (cont.)

12 12 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Teeth (cont.)  The tooth germ has three parts.  The enamel organ Produces enamel Produces enamel  The dental papilla Forms the dental pulp Forms the dental pulp  The dental sac or follicle The follicle provides cells that form cementum, the periodontal ligament, and alveolar bone. The follicle provides cells that form cementum, the periodontal ligament, and alveolar bone. Cementum is formed after the crown is complete. Cementum is formed after the crown is complete.

13 13 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Developmental Soft Tissue Abnormalities  (pgs )  Ankyloglossia  Commissural Lip Pits  Lingual Thyroid

14 14 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Ankyloglossia  (pg. 158)  An extensive adhesion of the tongue to the floor of the mouth  Due to the complete or partial fusion of the lingual frenum Some patients may have no adverse effects, while others may have difficulty with speech. Some patients may have no adverse effects, while others may have difficulty with speech. It may just involve mucosa, or it may be muscular and thick. It may just involve mucosa, or it may be muscular and thick.  Treatment  Frenectomy This works nicely with a laser. This works nicely with a laser.

15 15 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Ankyloglossia (cont.)

16 16 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Commissural Lip Pits  (pgs )  Epithelium-lined blind tracts located at the corners of the mouth (commissure)  May be shallow or several millimeters deep.  Congenital lip pits may also be observed near the midline of the vermilion border.  Treatment  None

17 17 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Commissural Lip Pits (cont.)

18 18 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Lingual Thyroid  (pg. 159)  A small mass of thyroid tissue located on the tongue  Results from the failure of the primitive thyroid tissue to migrate from its developmental location in the area of foramen cecum on the posterior portion of the tongue to its normal position in the neck

19 19 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Lingual Thyroid (cont.)  Appears as a smooth nodular mass posterior to circumvallate papillae at the base of the tongue.  TreatmentS  It may be removed if it is obstructive, providing the patient has other functioning thyroid tissue.

20 20 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Developmental Cysts  Odontogenic Cysts  NonodontogenicS Cysts  Pseudocysts

21 21 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Developmental Cysts (cont.)  (pg. 159) (Box 5-1)  An abnormal fluid-filled epithelium-lined sac or cavity  Found throughout the body, including the head and neck region

22 22 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Developmental Cysts (cont.)  Developmental cysts are classified as to whether they are odontogenic or nonodontogenic.  They are also classified according to location, cause, origin of the epithelial cells, and histologic appearance.

23 23 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Developmental Cysts (cont.)  They can cause expansion of bone.  Intraosseous cysts Occur within bone Occur within bone  Extraosseous cysts Occur in soft tissue Occur in soft tissue  Cysts within bone generally appear as well-circumscribed radiolucencies.  They may appear as unilocular or multilocular.

24 24 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Odontogenic Cysts  Dentigerous Cyst  Eruption Cyst  Primordial Cyst  Odontogenic Keratocyst  Calcifying Odontogenic Cyst  Lateral Periodontal Cyst and Gingival Cyst

25 25 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Dentigerous Cyst (Follicular Cyst)  (pgs )  Forms around the crown of an unerupted or developing tooth  The epithelial lining originates from the reduced enamel epithelium after the crown has formed and calcified.  Most commonly around the crown of an unerupted or impacted third molar

26 26 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Dentigerous Cyst (Follicular Cyst) (cont.)

27 27 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Dentigerous Cyst  (pgs )  Radiographic  A well-defined, unilocular radiolucency around the crown of an unerupted or impacted tooth  Histologic  The lumen is most characteristically lined with cuboidal epithelium surrounded by a wall of connective tissue.  Treatment  Removal of the cyst There is some risk of cystic transformation into a neoplasm. There is some risk of cystic transformation into a neoplasm.

28 28 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Dentigerous Cyst (cont.)

29 29 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Eruption Cyst  (pg. 160)  Similar to a dentigerous cyst  Found in the soft tissue around the crown of an erupting tooth  Treatment  None

30 30 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Primordial Cyst  (pgs )  Develops in the place of a tooth  Most commonly in place of a third molar  Most often seen in young adults and discovered on radiographic examination

31 31 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Primordial Cyst

32 32 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Primordial Cyst (cont.)  Histologic  The lumen is lined by stratified squamous epithelium surrounded by parallel bundles of collagen fibers.  It may prove to be an odontogenic keratocyst or a lateral periodontal cyst.  Treatment  Surgical removal  The risk of recurrence depends on the diagnosis.

33 33 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Odontogenic Keratocyst (OKC)  (pgs )  Characterized by histologic appearance and frequent recurrence  The lumen of the cyst contains perakeratin.  Most often seen in the mandibular third molar region  Can move teeth and cause resorption

34 34 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Odontogenic Keratocyst  (pgs )  Histologic  The lumen is lined by epithelium that is 8 to 10 cell layers thick and surfaced by parakeratin.  Radiographic  Frequently appears as a well-defined, multilocular, radiolucent lesion

35 35 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Odontogenic Keratocyst (cont.)  (pgs )  Treatment  Due to a high recurrence rate, surgical excision and osseous curettage are recommended.

36 36 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Calcifying Odontogenic Cyst (COC)  (pg. 163)  A nonaggressive, cystic lesion lined by odontogenic epithelium  Closely resembles an ameloblastoma  Has a characteristic feature called ghost cells

37 37 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Lateral Periodontal Cyst and Gingival Cyst  (pgs )  Most often seen in the mandibular cuspid and premolar area  An asymptomatic, unilocular or multilocular radiolucent lesion on the lateral surface of a tooth root  Found most often in males

38 38 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Lateral Periodontal Cyst and Gingival Cyst (cont.)  (pgs )  Histologic  A gingival cyst has the same type of lining, but is located in the soft tissue.  A thin band of stratified squamous epithelium lines the cyst  Treatment  Surgical excision

39 39 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Lateral Periodontal Cyst and Gingival Cyst (cont.)

40 40 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Nonodontogenic Cysts  Nasopalatine Canal Cyst  Median Palatine Cyst  Globulomaxillary Cyst  Median Mandibular Cyst  Nasolabial Cyst  Branchial Cleft Cyst (Lymphoepithelial Cyst)  Epidermal Cyst  Dermoid Cyst and Benign Cystic Teratoma  Thyroglossal Tract Cyst

41 41 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Nasopalatine Canal Cyst (Incisive Canal Cyst)  (pg. 164)  Located within the nasopalatine canal or the incisive papilla  Most commonly seen in men between 40 and 60 years old  Usually asymptomatic  May see a small, pink bulge near the apices and between the roots of the maxillary central incisors on the lingual surface

42 42 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Nasopalatine Canal Cyst  (pg. 164)  Radiographic  A well-defined, radiolucent lesion  May be oval or heart-shaped  Histologic  Lined by epithelium varying from stratified squamous to pseudostratified ciliated columnar epithelium  Treatment  Surgical excision

43 43 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Nasopalatine Canal Cyst (cont.)

44 44 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Median Palatine Cyst  (pgs )  A well-defined, unilocular radiolucency  Located in the midline of the hard palate  Histologic  Lined with stratified, squamous epithelium surrounded by dense fibrous connective tissue  Treatment  Surgical removal

45 45 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Median Palatine Cyst (cont.)

46 46 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Globulomaxillary Cyst  (pg. 165)  A well-defined, pear-shaped radiolucency found between the roots of the maxillary lateral incisor and cuspid  Was once thought to be a fissural cyst, now believed to be of odontogenic epithelial origin  Treatment  Surgical removal

47 47 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Globulomaxillary Cyst (cont.)

48 48 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Median Mandibular Cyst  (pg. 165)  A rare lesion located in the midline of the mandible  Lined with squamous epithelium  Radiographic  A well-defined radiolucency below the apices of mandibular incisors  Treatment  Surgical removal

49 49 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Nasolabial Cyst  (pgs )  A soft tissue cyst  Thought to originate from the lower anterior portion of the nasolacrimal duct  Observed in adults from 40 to 50 years of age  4:1 ratio in favor of females

50 50 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Nasolabial Cyst (cont.)  (pgs )  Clinical  An expansion or swelling in the mucobuccal fold in the area of the maxillary canine and the floor of the nose  Histologic  Lined with pseudostratified, ciliated columnar epithelium and multiple goblet cells  Treatment  Surgical excisions

51 51 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Nasolabial Cyst (cont.)

52 52 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Branchial Cleft Cyst (Lymphoepithelial Cyst)  (pgs )  Most commonly found in major salivary glands  A stratified squamous epithelial lining surrounded by a well-circumscribed component of lymphoid tissue  Appears to arise from epithelium trapped in a lymph node during development

53 53 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Branchial Cleft Cyst (Lymphoepithelial Cyst) (cont.)

54 54 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Branchial Cleft Cyst (Lymphoepithelial Cyst) (cont.)  Most commonly found intraorally on the floor of the mouth and the lateral borders of the tongue  Appears as a pinkish, yellow raised nodule  Treatment  Surgical excision

55 55 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Epidermal Cyst  (pg. 166)  A raised nodule on the skin of the face or neck  May be noted intraorally on occasion  Histologic  Lined by keratinizing epithelium the resembles the epithelium of the skin  The lumen is usually filled with keratin scales  Treatment  Surgical excision

56 56 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Dermoid Cyst and Benign Cystic Teratoma  (pg. 166)  A developmental cyst often present at birth or noted in young children  It is usually found on the floor of the mouth when it is located in the oral cavity.  May have a doughy consistency when palpated

57 57 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Dermoid Cyst  Histologic  Lined by orthokeratinized, stratified squamous epithelium surrounded by a connective tissue wall  The lumen is usually filled with keratin  Hair follicles, sebaceous glands, and sweat glands may be seen in the cyst wall  Benign cystic teratoma Resembles a dermoid cyst Resembles a dermoid cyst  Treatment  Surgical excision

58 58 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Thyroglossal Tract Cyst  (pgs )  Forms along the tract the thyroid gland follows in development  Most often found in young individuals under 20 years of age  No sex predilection  Treatment  Excision of the cyst and tract

59 59 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Thyroglossal Tract Cyst (cont.)

60 60 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Pseudocysts  Static Bone Cyst  Simple Bone Cyst  Aneurysmal Bone Cyst

61 61 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Static Bone Cyst (Lingual Mandibular Bone Cavity) (Stafne Bone Cyst)  (pgs. 166, 168)  A pseudocyst (not a true cyst)  A well-defined cystlike radiolucency may be observed on radiograph in the posterior region of the mandible inferior to the mandibular canal.  Caused by a lingual depression in the mandible  Treatment  None

62 62 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Static Bone Cyst (Lingual Mandibular Bone Cavity) (Stafne Bone Cyst) (cont.)

63 63 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Simple Bone Cyst (Traumatic Bone Cyst)  (pg. 168)  A pathologic cavity in bone that is not lined with epithelium  May be associated with trauma  Radiographic  A well-defined unilocular or multilocular radiolucency  Characteristically shows scalloping around roots of teeth  Treatment  Curettage on the wall lining the void

64 64 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Simple Bone Cyst (Traumatic Bone Cyst) (cont.)

65 65 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Aneurysmal Bone Cyst  (pg. 168)  A pseudocyst  Consists of blood filled spaces surrounded by multinucleated giant cells and fibrous connective tissue

66 66 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Aneurysmal Bone Cyst (cont.)  Radiographic  Multilocular appearance “honeycomb,” “soap bubble”  Usually seen in persons less than 30 years old  Slight predilection for females  Treatment  Surgical excision

67 67 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Developmental Abnormalities of Teeth  Abnormalities in the Number of Teeth  Abnormalities in the Size of Teeth  Abnormalities in the Shape of Teeth  Abnormalities of Tooth Structure  Abnormalities of Tooth Eruption

68 68 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Abnormalities in the Number of Teeth  Anodontia  Hypodontia  Supernumerary Teeth

69 69 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Anodontia  (pgs )  The congenital lack of teeth  Total anodontia is lack of all teeth.  May be associated with ectodermal dysplasia

70 70 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Hypodontia  (pg. 169)  The lack of one or more teeth  May affect either deciduous or permanent teeth  The most common missing permanent teeth are  Mandibular and maxillary third molars  Maxillary lateral incisors  Mandibular second premolars  The most common missing deciduous tooth is the mandibular incisor.

71 71 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Hypodontia (cont.)

72 72 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Hypodontia (cont.)  Usually identified during clinical and radiographic examination  Tends to be familial  Treatment  May require prosthetic replacement  Orthodontic evaluation and treatment may be necessary  May be a component of a syndrome

73 73 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Supernumerary Teeth  (pgs )  Extra teeth found in the dental arches  May result from formation of extra tooth buds in the dental lamina or from the cleavage of already existing tooth buds  May occur in either deciduous or permanent dentition  Most often seen in the maxilla  Most are found on radiographs

74 74 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Supernumerary Teeth (cont.)

75 75 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Supernumerary Teeth (cont.)  (pgs. 169, )  Mesiodens  The most common supernumerary tooth  Located between maxillary incisors  May be inverted when seen on radiographs  Distomolar  The second most common supernumerary tooth  Located distal to the third molar

76 76 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Supernumerary Teeth (cont.)

77 77 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Supernumerary Teeth (cont.)  Treatment  Erupted teeth may require removal if they cause crowding, malposition of adjacent teeth, or noneruption of normal teeth.  Nonerupted teeth “should be extracted because a risk exists for cyst development around the crown.”  Multiple supernumerary teeth may be associated with cleidocranial dysplasia or Gardner syndrome.

78 78 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Abnormalities in the Size of Teeths  Microdontia  Macrodontia

79 79 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Microdontia  (pgs. 170, 172) (Fig. 5-24)  One or more teeth are smaller than normal.  True generalized microdontia Seen in a pituitary dwarf; all teeth are smaller than normal Seen in a pituitary dwarf; all teeth are smaller than normal  Generalized relative microdontia Normal-sized teeth appear small in a large jaw. Normal-sized teeth appear small in a large jaw.  Microdontia involving a single tooth Maxillary lateral incisor and maxillary third molar are the most commonly involved teeth. Maxillary lateral incisor and maxillary third molar are the most commonly involved teeth.

80 80 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Microdontia (Cont.)

81 81 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Macrodontia  (pg. 170)  One or more teeth are larger than normal.  True generalized macrodontia Seen in cases of pituitary giantism Seen in cases of pituitary giantism  Relative generalized macrodontia Large teeth in a small jaw Large teeth in a small jaw  Macrodontia affecting a single tooth May be seen in cases of facial hemihypertrophy May be seen in cases of facial hemihypertrophy

82 82 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Abnormalities in the Shape of Teeths  Gemination  Fusion  Concrescence  Dilaceration  Enamel Pearl  Talon Cusp  Taurodontism  Dens in Dente  Dens Evaginatus  Supernumerary Rootsss

83 83 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Gemination  (pgs , 173)  Occurs when a single tooth germ attempts to divide in two  Appears as two crowns joined together by a notched incisal area  Radiographically, usually one single root and one common pulp canal exist  The patient has a full complement of teeth.

84 84 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Gemination (cont.)

85 85 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Fusion  (pgs )  The union of two normally separate adjacent tooth germs  Appears as a single large crown that occurs in place of two normal teeth  Radiographically, either separate or fused roots and root canals are seen.  The patient is usually short one tooth.

86 86 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Fusion (cont.)

87 87 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Concrescences  (pgs. 172, 174)  Two adjacent teeth are united by cementum.  Usually discovered on radiograph  If one of the teeth needs to be removed, both usually come out (two for the price of one).

88 88 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Concrescences (cont.)

89 89 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Dilaceration  (pgs. 172, )  An abnormal curve or bend in the root of a tooth  Usually discovered on radiograph  May cause a problem if the tooth must be removed or a root canal performed

90 90 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Dilaceration (cont.)

91 91 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Enamel Pearl  (pgs. 174, 176)  A small, spherical enamel projection on a root surface  Usually found on maxillary molars  Radiographically, it appears as a small, spherical radiopacity.  Difficult to instrument with curettes or scalers  Removal may be necessary if periodontal problems occur in the furcation.

92 92 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Enamel Pearl (cont.)

93 93 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Talon Cusp  (pgs. 174, 176)  An accessory cusp located in the cingulum area of a maxillary or mandibular permanent incisor  Contains a pulp horn  May interfere with occlusion

94 94 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Talon Cusp (cont.)

95 95 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Taurodontism  (pgs. 174, 176)  The teeth have elongated pulp chambers and short roots.  May occur in both deciduous and permanent dentition  Identified on radiographs

96 96 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Taurodontism (cont.)

97 97 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Dens in Dente  (pgs. 175, 177)  Occurs when the enamel organ invaginates into the crown of a tooth before mineralization  Radiographically, it appears as a toothlike structure within a tooth.  Vulnerable to caries, pulpal infection, and necrosis  A restoration can be placed in the pit if the tooth is vital.

98 98 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Dens in Dente (cont.)

99 99 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Dens Evaginatus  (pgs )  An accessory enamel cusp found on the occlusal tooth surface  Most often seen on mandibular premolars  May cause occlusal problems

100 100 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Dens Evaginatus (cont.)

101 101 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Supernumerary Roots  (pgs )  May involve any tooth  Most commonly, maxillary and mandibular third molars if multirooted teeth are involved.  May become clinically significant if removal or endodontia is necessary

102 102 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Supernumerary Roots

103 103 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Abnormalities of Tooth Structure  Enamel Hypoplasia  Enamel Hypocalcification  Endogenous Staining of Teeth  Regional Odontodysplasia

104 104 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Enamel Hypoplasia  (pgs )  The incomplete or defective formation of enamel  Can affect either deciduous or permanent dentition  May be due to many factors  Amelogenesis imperfecta  Febrile illness (measles, chickenpox, scarlet fever)  Vitamin deficiency  Infection of a deciduous tooth  Ingestion of fluoride  Congenital syphilis  Birth injury, premature birth  Idiopathic factors

105 105 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Enamel Hypoplasia Caused by Febrile Illness or Vitamin Deficiency  (pgs )  Ameloblasts are one of the most sensitive cell groups in the body.  Any serious systemic disease or severe nutritional deficiency can produce enamel hypoplasia.  One or more horizontal rows of tiny, deep pits are seen traversing the affected tooth surface.

106 106 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Enamel Hypoplasia Caused by Febrile Illness or Vitamin Deficiency (cont.)

107 107 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Enamel Hypoplasia Resulting from Local Infection or Trauma  (pg. 178)  Enamel hypoplasia of an adult tooth may result from infection of a deciduous tooth.  A single tooth is usually affected; it is referred to as a Turner tooth.  The color of the enamel may range from yellow to brown, or severe pitting and deformity may be involved.

108 108 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Enamel Hypoplasia Resulting from Fluoride Ingestion  (pg. 178)  Affected teeth exhibit a mottled discoloration of enamel.  Ingestion of water with 2 to 3 times the recommended amount leads to white flecks and chalky opaque areas of enamel.  Four times the recommended amount of fluoride causes brown or black staining.

109 109 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Enamel Hypoplasia Resulting from Fluoride Ingestion (cont.)

110 110 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Enamel Hypoplasia Resulting from Congenital Syphilis  (pgs )  Congenital syphilis is transmitted from an infected mother to her fetus via the placenta.  This may result in enamel hypoplasia of adult incisors and first molars. Hutchinson incisors are shaped like screwdrivers. Hutchinson incisors are shaped like screwdrivers. Mulberry molars have a berrylike appearance. Mulberry molars have a berrylike appearance.

111 111 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Enamel Hypoplasia Resulting from Congenital Syphilis (cont.)

112 112 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Enamel Hypoplasia Resulting from Birth Injury, Premature Birth, or Idiopathic Factors  (pg. 179)  Enamel hypoplasia may occur due to trauma or injury at the time of birth.  Even a mild illness or systemic problem can result in enamel hypoplasia.

113 113 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Enamel Hypocalcification  (pg. 179)  A developmental anomaly resulting in a disturbance or the maturation of the enamel matrix  Usually appears as a chalky, white spot on the middle third of smooth crowns  The underlying enamel may be soft and susceptible to caries.

114 114 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Endogenous Staining of Teeth  (pg. 179)  The result of deposition of substances circulating systemically during tooth development  May be due to Tetracycline stain Tetracycline stain Erythroblastosis fetalis – Rh incompatibility Erythroblastosis fetalis – Rh incompatibility Neonatal liver disease Neonatal liver disease Congenital porphyria – an inherited metabolic disease Congenital porphyria – an inherited metabolic disease

115 115 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Regional Odontodysplasia (Ghost Teeth)  (pgs )  One or several teeth in the same quadrant exhibit a marked reduction in radiodensity and a characteristic ghostlike appearance.  Very thin enamel and dentin are present  May affect primary or adult dentition  Usually treated by extraction

116 116 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Regional Odontodysplasia (Ghost Teeth) (cont.)

117 117 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Abnormalities of Tooth Eruption  (pgs )  Impacted and embedded teeth  Impacted teeth cannot erupt due to an obstruction.  Embedded teeth do not erupt due to lack of eruptive force.  Ankylosed teeth

118 118 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Impacted and Embedded Teeth  (pg. 180)  Any tooth can be impacted.  Third molar impactions are classified according to the position of the tooth.  Teeth can be completely impacted in bone or they may be partially impacted.  Partially impacted teeth are prone to infection.

119 119 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Impacted and Embedded Teeth (cont.)

120 120 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Impacted and Embedded Teeth (cont.)  Impacted teeth may be surgically removed to prevent odontogenic cyst and tumor formation or damage to adjacent teeth.  Partially impacted third molar teeth are removed to prevent infections.  The optimal time is between 12 and 24 years of age.

121 121 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Ankylosed Teeth  (pgs )  Tooth cementum fused to bone  Prevents exfoliation of the deciduous tooth and eruption of the underlying adult tooth  The ankylosed deciduous tooth appears submerged and has a different sound when percussed (kind of a dull thud).

122 122 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Ankylosed Teeth (cont.)

123 123 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Ankylosed Teeth (cont.)  The periodontal ligament space is lacking.  Difficult to extract  Removal of deciduous teeth is necessary for eruption of the adult successor.  Removal of adult teeth may be necessary to prevent malocclusion, caries, and periodontal disease.

124 124 Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Discussion Questions  What developmental soft tissue abnormalities may be observed within the oral cavity?  What developmental cysts may be observed within the oral cavity?  What developmental abnormalities of teeth may be observed within the oral cavity?


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