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.
Standard Abbreviations for Prescribers
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 Disorders of Tooth Development and Eruption
CHAPTER MENU
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
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
1.1 Anodontia, Hypodontia and Oligodontia
1.1.1 Definition/Description
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
1.1.2 Frequency
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 childrenFigure 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).
1.1.3 Aetiology/Risk Factors
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
1.1.4 Clinical Features
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