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

Atypia: deviation from normal or a state of being not typical. Atypical cells are not necessarily cancerous.

Colloid bodies (also called Civatte bodies): these apoptotic keratinocytes are oval or round, immediately above or below the epidermal or epithelial basement membrane.

Hydropic (liquefaction) degeneration: basal cells become vacuolated, separated, and disorganized.

Hyaline bodies: necrotic keratocytes; also termed colloid bodies, Civatte bodies, and apoptotic bodies.

ac(before meals) ad lib(as desired) ASAP(as soon as possible) bid(twice a day) btl(bottle) c(with) cap(capsule) crm(cream) disp(dispense on a prescription label) elix(elixir) g(gram) gtt(drop) h(hour) hs(at bedtime) iu(international units) IV(intravenous) l(litre) liq(liquid) loz(lozenge) mg(milligram) min(minute) ml(millilitre) NaF(sodium fluoride) prn(as needed) q(every) q2h(every 2 hours) q4h(every 4 hours) q6h(every 6 hours) q8h(every 8 hours) q12h(every 12 hours) qam(every morning) qd(every day) qhs(every bedtime) qid(four times a day) qod(every other day) qpm(every evening) qsad(add a sufficient quantity to equal) qwk(every week) Rx(prescription) s(without) sig(patient dosing instructions on prescription label) sol(solution) stat(Immediately) syr(syrup) tab(tablet) tbsp(ttablespoon) tid(three times a day) top(topical) tsp(teaspoon) oint(ointment) OTC(over the counter) oz(ounce) p(after) pc(after meals) PO(by mouth) U(unit) ut dict(as directed) visc(viscous) wk(week) yr(year)

1 1.1 Anodontia, Hypodontia and Oligodontia

2 1.2 Hyperdontia (Supernumerary Teeth)

3 1.3 Microdontia and Macrodontia

4 1.4 Gemination, Fusion and Concrescence

5 1.5 Taurodontism and Dilaceration

6 1.6 Amelogenesis Imperfecta

7 1.7 Dentinogenesis Imperfecta

8 1.8 Dentinal Dysplasia (Dentin Dysplasia)

9 1.9 Regional Odontodysplasia (Ghost Teeth)

10 1.10 Delayed Tooth Eruption

11 1.11 Tooth Impaction (Impacted Teeth)

12 1.12 Dens Invaginatus and Dens Evaginatus

13 1.13 Fluorosis (Mottled Enamel)

14 1.14 Tetracycline‐Induced Discolouration of Teeth: Key Features

15 1.15 Enamel Pearl: Key Features

16 1.16 Talon Cusp: Key Features

17 1.17 Hutchinson's Incisors and Mulberry Molars: Key Features

18 1.18 Tooth Ankylosis: Key Features

19 1.19 Supernumerary Roots: Key Features

Anodontia: All teeth are developmentally (congenitally) missing

Hypodontia: one to six developmentally (congenitally) missing teeth except the third molars

Oligodontia: more than six developmentally (congenitally) missing teeth

Anodontia: extremely rare

Hypodontia: incidence: 4.4–13.4%. The most common developmental anomaly

Oligodontia: incidence: 0.25%

Hypodontia of the deciduous teeth affects less than 1% of children Figure 1.1 Hypodontia: clinical photograph of missing maxillary lateral incisors(source: Bin im Garten, https://commons.wikimedia.org/wiki/File:Hypodontie_der_zweiten_oberen_Schneidz%C3%A4hne_IMG_1726.JPG. Licensed under CC BY‐SA 3.0).

Anodontia: mutations in EDA, EDAR and EDARADD genes

Hypodontia: mutations in MSX1, PAX9, IRF6, GREM2, AXIN2, LRP6, SMOC2, LTBP3, PITX2 and WNT10B. WNT10A genes

Oligodontia: mutations in MSX1, PAX9, IRF6, GREM2, AXIN2, LRP6, SMOC2, LTBP3, PITX2 and WNT10B. WNT10A genes

Environmental factors: hypodontia can result from trauma to the developing dental tissues such as chemotherapy or radiotherapy

The most common missing multiple teeth (other than third molars) are:Maxillary lateral incisors ( Figure 1.1). This is followed by the mandibular second premolars and maxillary second premolarsSkin/nails/hair/sweat glands may be affected in some cases of hypodontiaMorphology of teeth may be defective (microdontia/peg‐shaped laterals) in hypodontiaIn Down syndrome oligodontia is commonHypodontia/oligodontia might also be associated with cleft lip and palateOver retention of the overlying deciduous tooth (because of the missing permanent tooth germ) occurs frequently

In many cases routine radiography may reveal developmentally missing teeth

History

Clinical examination

Radiography

Prosthodontic treatment/implants or orthodontic treatment for edentulous spaces

Hyperdontia/supernumerary teeth: excess number of teeth beyond the expected 20 deciduous and 32 permanent teeth

The shape of the supernumerary tooth may resemble a tooth of the normal series. In this case, the extra tooth is called supplemental tooth

98% of supernumerary teeth occur in the maxilla

In 1% of the population, a supernumerary tooth occurs in the midline in anterior maxilla; this is called mesiodens

Budding of the dental lamina: stimulus for budding is not known

Asymptomatic: supernumerary teeth may be detected incidentally on radiography for other reasons

Supernumerary teeth are five times more common in the permanent dentition than in the deciduous dentition

Supernumerary teeth may be single or multiple, unilateral or bilateral, and may be present in one or both jaws.

The most common single supernumerary tooth: midline of the anterior maxilla, known as a mesiodens. This is also an example of microdontia

Other supernumerary teeth: maxillary fourth molars, maxillary lateral incisors, mandibular fourth molars and mandibular premolars

The most common site for multiple supernumerary teeth is the mandibular premolar region ( Figure 1.2) Figure 1.2 Supernumerary premolars located lingual to the mandibular first and second premolars.

A supernumerary tooth lingual or buccal to a molar is called a paramolar

A supernumerary tooth located distal to a third molar is called a distomolar

Supernumerary teeth are common in patients with cleidocranial dysplasia and Gardner syndrome

Complications of supernumerary teeth may include:Delayed or ectopic eruption of adjacent teethRoot resorption of adjacent teethCrowdingMalocclusionDiastemaPericoronal cyst or infection