Dental Anomalies 2

Question 1

What are the common anomalies of shape?

Answer 1

Double teeth (fusion or germination)

Accessory cusps (Talon cusp or evaginated odontome)

Invaginated odontome

Taurodontism

Question 2

What causes double tooth?

Answer 2

Inherited

Local factors:

Union of 2 adjacent tooth buds

Partial splitting of one into 2

Tooth germ move together because of crowding or trauma

Question 3

in who is double tooth most common? Where is it more likely to be seen?

Answer 3

M =F

More common in primary dentition than permanent dentition.

Can be unilateral or bilateral

Predominantly incisor region

More common in the maxilla

Bilateral in primary dentition means more likely having anomalies in permanent dentition

Question 4

What are the clinical features of double teeth?

Answer 4

Fused teeth might have one or two pulp chambers

Fused teeth commonly exhibit labial and lingual vertical grooves on the crown surface

If the affected tooth is counted as one there is usually one tooth less than normal for a given dental age.

Question 5

What is gemination?

Answer 5

Gemination is the formation of 2 teeth from the same follicle.

Question 6

What does gemination look like usually?

Answer 6

One pulp chamber is common

In permanent dentition these teeth are usually macrodonts

Question 7

Which jaw is gemination more common in?

Answer 7

Gemination is more common in the maxilla

Question 8

How is diagnosis of root canal morphology from gemination done?

Answer 8

Diagnosis of root canal morphology may be aided by use of CBCT as plain films are difficult to interpret.

Question 9

What clinical problems are associated with double tooth?

Answer 9

Caries in the groove dividing the bifid crown

Periodontal disease due to extension of the groove to the root surface

Excess arch space and diastema occurs when normal teeth are fused

Crowding of the dental arch, if the fusion involves one normal tooth and a supernumerary tooth

Aplasia of the permanent successor in case of fusion

Delayed exfoliation and root resorption of primary double teeth

Impaction of the permanent successor.

Malocclusion

Esthetic problems

Question 10

How is double tooth managed?

Answer 10

Fissure sealant

Flowable composite resin

Hemi-section

Reshaping or reduction of a double tooth

Orthodontic treatment and/or prosthetic replacement

Extraction and replacement with an implant

Question 11

What is a talon cusp?

Answer 11

Process of horn-like shape curving from the base to the cutting edge on the palatal surface of the incisors

Question 12

Who most commonly gets talon cusp?

Answer 12

Males > Females 1.9:1 ratio

Rare in primary dentition (0.5 - 0.6%)

Observed only in maxillary anterior teeth and involves the incisors and canines

Question 13

What causes talon cusp?

Answer 13

Unknown

Multifactorial involving both genetic and environmental factors

May occur because of an outward folding of the inner enamel epithelium

Hyperactivity of the dental lamina (commonly in the anterior region)

Due to fusion of a normal and supernumerary tooth

Question 14

What are the types of talon cusps?

Answer 14

Type 1 = Talon, well defined cusp, extends at least half the distance from the cemento-enamel junction to the incisal edge.

Type 2 = semi-talon, additional cusp of 1mm or more but less than half the distance from the cemento-enamel junction to incisal edge.

Type 3 = trace talon, enlarged and prominent cingulum with variations

Question 15

What is the radiographic appearance of the talon cusp?

Answer 15

Resembles radio-opaque v-shaped structure pointing towards incisal edge of the tooth.

Cusp image outlined by 2 distinct white lines, representing the enamel.

Question 16

Which syndromes are associated with talon cusps?

Answer 16

Rubinstein-Taybi syndrome

Mohr syndrome [oral-facial-digital II]

Sturge-weber syndrome

Incontinentia pigmentia

Ellis-van Creveld syndrome [chondroectodermal dysplasia]

Alagille’s syndrome

Question 17

What are the complications assocaited with talon cusp?

Answer 17

Compromised aesthetics

Traumatic occlusion

Displacement of affected or opposing teeth

Plaque retention

Caries susceptibility in developmental grooves delineate the cusp

Pulpal necrosis

Hypersensitivity

Periodontal problems

Attrition of opposing teeth accidental cusp fracture

Peripaical pathosis due to excessive attrition

Irritation of tongue during speech and mastication

Interference with tongue space

Speech disturbance

Breast-feeding problems

TMJ joint pain due to excessive occlusal forces

Question 18

How is a talon cusp managed?

Answer 18

Fissure sealants or flowable composite resin to prevent caries in the grooves

If no occlusal interference, no treatment is required

If occlusal interference present: Gradual and periodic reduction of enamel only (to avoid pulp exposure) with fluoride as a de-sensitising agent.

Elective pulpotomy

Partial pulpotomy

Extraction followed by orthodontic treatment.

Question 19

What is a dens evaginatus?

Answer 19

An enamel covered tubercle projecting from the occlusal surface of a premolar and in rare instances canines and molars.

Question 20

What causes dens evaginatus?

Answer 20

Unknown:

Multifactorial association with racial and genetic factors.

Abnormal proliferation of the inner enamel epithelium into stellate reticulum of the enamel caused by:

Either an outflowing of the enamel epithelium

Or by a transient focal hyperplasia of the primitive pulpal mesenchyme

Question 21

Where is a dens evaginatus most commonly located?

Answer 21

Mostly found on permanent teeth

Typically occurs on premolar teeth

Demonstrate marked mandibular predominance

Teeth with dens evaginatus usually occur bilaterally

Prevalence between 0.1% and 4.7%

Frequently seen in mongoloids, Asians, the inuit, and native americans. Rare in whites.

Question 22

How is dens evaginatus classified?

Answer 22

According to location: Tubercle can arise from lingual ridge of buccal cusp, or center of the occlusal surface.

According to form of the projection: Smooth, grooved, terraced, or ridged.

According to pulp contents within the tubercle (Wide pulp horns, narrow pulp horns, constricted pulp horns, isolated pulp horn remnants, or no pulp horn)

Question 23

What radiographic examinations should be done for a dens evaginatus?

Answer 23

The pulp tissue in the tubercle is normal unless it is fractured or worn down, thereby permitting bacterial invasion with consequent pulpal necrosis.

Necrosis of pulp can lead to dentoalveolar abscess

Other findings include:

Osteomyelitis

Thickening of periodontal membrane

Periapical rarefaction

Incomplete root formation

Fracture of the root

Cyst formation

Dilaceration

Question 24

How is dens evaginatus managed?

Answer 24

Composite reinforcement

Grinding of the tubercle

Trauma or attrition to the tubercle results in pulp exposure

Revascularization

Extraction of the tooth

Question 25

What is a dens invaginatus?

Answer 25

An infolding of the enamel and dentin towards the pulp

AKA:

Warty teeth

Invagination of enamel

Dens in dente

Invaginated odontome

Question 26

What causes dens invaginatus?

Answer 26

Unknown; several theories:

Growth pressure: Buckling of enamel organ caused by forces in developing arch.

Focal growth retardation: Invagination results from a focal failure of growth of the internal enamel epithelium. Surrounding normal epithelium continues to proliferate and engulfs the static area.

FOCAL PROLIFERATION: Invagination is the result of an invasion of dental papilla by a rapid and aggressive proliferating area of internal enamel epithelium.

Local causes: Trauma and infection

Genetic

Question 27

How commonly is dens invaginatus seen in primary dentition and on which teeth?

Answer 27

More rare in primary dentition (0.1%) Seen most commonly in primary canine, maxillary central incisors, and mand 2nd molars.

Question 28

How commonly is dens invaginatus seen in permanent dentition and on which teeth?

Answer 28

0.2 - 10%

Male > female

Maxillary lateral incisors, maxillary central incisors and canines

Question 29

How is dens invaginatus classified?

Answer 29

Coronal vs radicular

Type 1: Confined to crown

Type 2: Beyond CEJ without involving PA tissues

Type 3: Extends past CEJ and perforating laterally (3a) or apically (3b) at foramen

Question 30

What are the clinical features of dens invaginatus?

Answer 30

Tooth crowns and roots may exhibit variations in size and form

Invagination allows entry of irritants into the area, predisposing tooth to dental caries. Remember that enamel and dentine is thin between the dens and the pulpal tissues.

Pulp necrosis often occurs within few years of eruption, sometimes even before root end closure.

May lead to abscess formation or cellulitis

Retention or displacement of neighbouring teeth

Cyst formation

Internal resorption

Question 31

How should dens invaginatus be preventatively managed?

Answer 31

Preventative treatment such as fissure sealants + flowable composite

Question 32

How should dens invaginatus be restoratively managed?

Answer 32

Composite resin if caries are evident

Question 33

When should dens invaginatus be endodontically managed?

Answer 33

If symptomatic and root morphology is favourable

Question 34

When should a tooth with a dens invaginatus be extracted?

Answer 34

If internal anatomy is complex and the root canal is not possible

Infection

Endodontic failure

Orthodontic treatment planning should be carried out prior to extraction.

Question 35

What is taurodontism?

Answer 35

pulp cavity that tends to enlarge at the expense of the roots

Question 36

What causes taurodontism?

Answer 36

Unknown: Theory is due to delay or failure of invagination of Hertwig’s epithelial root sheath

Question 37

What is the prevalence of taurodontism?

Answer 37

M>F

Wide range in reported prevalence (5-60%!)

Question 38

What other anomalies are commonly associated with taurodontism?

Answer 38

Amelogenesis imperfecta

Hypodontia (35% prevalence in patients with hypodontia)

Question 39

What are the clinical implications of taurodontism?

Answer 39

Short but very curved canals

Canals difficult to visualize due to length of the pulp chamber