S. R. Prabhu - Handbook of Oral Pathology and Oral Medicine

Three types of dens invaginatus occur which can be detected on radiography:Type I: invagination ends in a blind sac, limited to the tooth crown ( Figure 1.10a)Type II: invagination extends to the cementoenamel junction extending in a blind sac. It may or may not extend into the root pulpType III: invagination extends to the interior of the root providing an opening to the periodontium, sometimes this presents another foramen in the apical region of toothDens evaginatus shows a tubercle on the occlusal surface ( Figure 1.10b)

History

Clinical examination (tooth morphology)

Radiography (intraoral periapical views)

Dens invaginatus: placement of sealants and endodontic treatment for severe cases

Dens evaginatus: removal of the tubercle and application of fluorides

Dental fluorosis (mottled enamel) is a qualitative defect of enamel resulting from an increase in fluoride concentration during enamel formation

Fluorosis is extremely common

Global variations exist. The global prevalence of fluorosis is reported to be about 32%

A higher than normal amount of fluoride ingestion while teeth are forming

When the level of fluoride is above 1.5 mg/l (1.5 ppm) in drinking water, dental fluorosis occurs

The severity of fluorosis is dependent on the dose and time of exposure to fluoride levels

Other sources of fluoride: toothpastes, mouth rinses, fluoride supplements, beverages (brick tea, tea and butter tea) and food (infant formula, fish, beans, potatoes and wheat)

Severity of fluorosis is dose dependent

Mild fluorosis: opaque lines following the perikymata

Moderate fluorosis: the opaque lines merge and more irregular cloudy areas become visible

Severe fluorosis: enamel is grossly defective with opaque chalky appearance and punched out pits. Extrinsic brown staining in the pits is frequent ( Figure 1.11)

Moderate to severe enamel fluorosis is called mottled enamel

Teeth with fluorosis are weak but resistant to caries

Turner's hypoplasia

Hypoplastic teeth in systemic disorders

Amelogenesis imperfecta

Early carious lesions

Tetracycline staining of teeth

History (residence/ migration, water fluoridation, other sources of fluorides in the diet)

Clinical examination

Aesthetic procedures as required Figure 1.11 Yellow‐brown discoloration of maxillary incisors due to fluorosis(source: From Mary A. Aubertin. 2014. Common Benign Dental and Periodontal Lesions. In: Diagnosis and Management of Oral Lesions and Conditions: A Resource Handbook for the Clinician. ed. Cesar A. Migliorati and Fotinos S. Panagakos. IntechOpen. doi: 10.5772/57597).

Close monitoring of sources of fluoride during the first three years of age

Water fluoridation: 0.7–1 ppm recommended

Use of fluoride tooth paste after 12 months of age

Infant formula with fluoridated water to be avoided

Fluoride supplements only in non‐fluoridated areas

Tetracycline is a broad‐spectrum antibiotic commonly used for infections

Tetracycline has several different analogues such as doxycycline, oxytetracycline, minocycline, chlortetracycline, demeclocycline

Tetracycline can stain teeth if ingested by the mother in the third trimester or by the child during the years of tooth formation of deciduous and permanent dentition

The discoloration, which is permanent, varies from yellow or grey to brown ( Figure 1.12)

Administration of tetracycline to pregnant women must be avoided during the second or third trimester of gestation and to children up to eight years of age.

Tetracycline‐stained teeth must be differentiated from dentinogenesis imperfecta Figure 1.12 Tetracycline‐induced grey/brown discolouration of deciduous teeth in a child(source: by kind permission of Professor Charles Dunlap, Kansas City, Kansas, USA).

The enamel pearl is a globule of enamel formation located on the root surface ( Figure 1.13)

It is characterized by a core of dentin covered by enamel and may contain a pulp chamber

Enamel pearl may cause periodontal pockets and periodontitis Figure 1.13 Enamel pearl on the cementum(source: by kind permission of Professor Charles Dunlap, Kansas City, Kansas, USA).

Talon cusp is a rare developmental anomaly presenting as a wisp‐like structure arising from the cervical region of anterior teeth

Resembles an eagle's talon Figure 1.14 Periapical radiograph of talon cusp on a partially erupted upper left permanent maxillary incisor in an eight‐year‐old boy. Note V‐shaped radiopaque structure overlapping the affected crown with its apex directed incisally(source: Matthew Fergusson, https://en.wikipedia.org/wiki/File:Talon_cusp.png. Licensed under CC BY‐SA 4.0).

In canines and incisors, it originates usually in the palatal cingulum as a tubercle projecting from the palatal surface

Its prevalence varies from less than 1% to approximately 8%

Radiographically, talon cusp appears as appears as a V‐shaped radiopaque structure overlapping the affected crown with its apex directed incisally ( Figure 1.14)

Symptoms include interference with occlusion, irritation of soft tissues, accidental cusp fracture and susceptible to dental caries

‘Hutchinson's incisors’ and ‘Mulberry molars’ are dental developmental defects seen in children with congenital syphilis; they are rare conditions

In Hutchinson's incisors, the incisal edge is either notched or screwdriver shaped. The bulbous crown is short and narrow (‘barrel shaped’). In the centre of the incisal edge a deep vertical central notch may be present ( Figure 1.15a)

Mulberry molars are characterized by multiple rounded rudimentary enamel cusps on the permanent first molars ( Figure 1.15b)

Hutchinson's incisors and mulberry molars are caused by direct invasion of tooth germs by Treponema organisms during tooth development Figure 1.15 (a) Hutchinson's incisors of congenital syphilis. Note screwdriver shape and central notch on the crowns of upper and lower permanent incisors. (b) Mulberry molars of congenital syphilis. Note multiple poorly formed globular cusps on the occlusal surfaces of mandibular permanent first molars.(source: images by kind permission of Professor Charles Dunlap, Kansas City, Kansas, USA.)

Anatomical fusion of tooth cementum with the alveolar bone:Mandibular primary first molars are frequently ankylosedAnkylosis of permanent teeth is uncommonA sharp solid note on percussion is noted, suggesting ankylosisPeriodontal ligament space is absent on radiographyIn many examples, the permanent successor is missing Figure 1.16 An extracted mandibular molar with three roots.

Normally, the permanent mandibular first molar has two roots, one mesial and one distal root

Rarely, an additional third root is seen, which is found distolingually, called the radix entomolaris ( Figure 1.16)