Disturbances of the Teeth and Jaws – Exam Review

75 question-and-answer flashcards covering disturbances of the jaws, developmental anomalies of lips, palate, and teeth, occlusal classification, enamel/dentine defects, eruption disturbances, and related syndromes to aid exam preparation.

What is agnathia?

A congenital absence (complete or partial) of the mandible or maxilla.

Which jaw components are most often absent in mandibular agnathia?

The condyle or ramus, sometimes unilaterally.

With unilateral absence of the mandibular ramus, which ear defect may be associated?

Ear deformity or agenesis.

Define micrognathia.

A small-appearing jaw, usually due to abnormal jaw-to-skull relationship rather than absolute size.

Name two conditions associated with true congenital mandibular micrognathia.

Pierre-Robin syndrome and certain congenital heart defects.

Which joint disturbance can cause acquired micrognathia?

Temporomandibular joint ankylosis, often from trauma or infection.

What is macrognathia and give one systemic cause.

Abnormally large jaws; seen in pituitary gigantism (hyperpituitarism), Paget’s disease, acromegaly, or leontiasis ossea.

How does mandibular macrognathia commonly manifest radiographically?

Increased ramus height and altered ramus-body angle resulting in mandibular prognathism.

What is Angle’s Class I occlusion?

Maxillary and mandibular dental arches are in normal mesiodistal relation.

Describe Angle’s Class II occlusion.

The mandibular arch is distal to normal relative to the maxillary arch.

Describe Angle’s Class III occlusion.

The mandibular arch is mesial to normal relative to the maxillary arch.

What is facial hemihypertrophy?

Idiopathic unilateral enlargement of facial tissues, sometimes part of body hemihypertrophy.

List two systemic neoplasms linked with childhood facial hemihypertrophy.

Adrenal tumors and kidney or liver neoplasms.

Orally, how are permanent teeth affected in facial hemihypertrophy?

Enlarged crowns and roots with premature eruption and exfoliation.

What syndrome is synonymous with facial hemiatrophy?

Parry-Romberg syndrome.

Give two oral features of facial hemiatrophy.

Hollow cheek, hemiatrophy of lips/tongue, deficient root development, delayed eruption.

What syndrome combines congenital lip pits with cleft lip/palate?

Van der Woude’s syndrome.

Where do commissural pits occur?

At the labial commissures, uni- or bilaterally.

Double lip is a feature of which syndrome?

Ascher’s syndrome (with blepharochalasis and non-toxic thyroid enlargement).

State the hereditary contribution to cleft lip with/without palate.

About 40 % of cases.

List three environmental factors implicated in cleft formation.

Vitamin deficiencies (A, D, E, K, B-complex), hormonal disturbances (cortisone, diabetes, thyroid disorders), infections (rubella, influenza A), radiation, drug exposure.

When is surgical repair of cleft lip typically performed?

Around 1 month of age, once birth weight is regained.

What is Cheilitis granulomatosa and its syndromic association?

Idiopathic diffuse lip swelling (often lower lip) linked to Melkersson-Rosenthal syndrome.

Cheilitis glandularis predisposes to which malignancy?

Epidermoid carcinoma of the lips.

Which intestinal polyposis syndrome shows oral mucosal pigment macules?

Peutz-Jeghers syndrome.

Differentiate microdontia types.

Generalised (all teeth small) vs. focal/localised (single tooth, e.g., peg-shaped maxillary lateral incisor).

Which endocrine disorder can produce generalised macrodontia?

Pituitary gigantism.

Define germination in tooth development.

Partial cleavage of a single enamel organ producing two crowns sharing one root canal.

How does fusion differ from germination?

Fusion is union of two separate tooth germs forming one large tooth; canals may be separate or shared.

What is concrescence?

Fusion of fully formed adjacent teeth by cementum only.

Dilaceration is usually caused by what?

Trauma during root development causing sharp root angulation.

Describe dens invaginatus.

Invagination of enamel/dentine forming a ‘tooth-within-a-tooth,’ predisposing to pulpitis.

Where are enamel pearls most often found?

Bifurcation areas of upper permanent molars below the cemento-enamel junction.

What radiographic feature characterises taurodontism?

Apically displaced furcation with elongated pulp chamber (bull-like tooth).

Dens evaginatus is most common on which teeth and populations?

Premolars of Asians, Inuits, and Native Americans; presents as an occlusal tubercle.

Which teeth most frequently show accessory roots?

Mandibular canines, premolars, and molars (especially third molars).

Define attrition.

Physiologic tooth wear from mastication, increasing with age.

How does erosion differ from abrasion?

Erosion: chemical loss of tooth structure; Abrasion: mechanical wear (e.g., toothbrush).

What is anodontia and its syndromic link?

Congenital absence of all teeth; often seen in ectodermal dysplasia.

Name the most common congenitally missing permanent teeth in hypodontia.

Third molars, maxillary lateral incisors, and second premolars.

What is a mesiodens?

A supernumerary tooth located between the maxillary central incisors.

Supernumerary teeth are associated with which familial syndrome?

Gardner’s syndrome.

Define natal teeth.

Structures resembling teeth present at birth, often epithelial keratinised nodules or prematurely erupted primary teeth.

What is enamel hypoplasia?

Incomplete or defective enamel formation producing thin or pitted enamel.

Differentiate the three clinical types of amelogenesis imperfecta.

Hypoplastic (thin enamel), hypocalcified (soft, easily removed enamel), hypomaturation (enamel pierced with explorer).

Which vitamins’ deficiencies can cause environmental enamel hypoplasia?

Vitamins A, C, and D.

Name three systemic conditions causing environmental enamel hypoplasia.

Exanthematous diseases (measles, chicken pox, scarlet fever), congenital syphilis, hypocalcaemia, birth injury/prematurity.

What genetic defect underlies dentinogenesis imperfecta types I and II?

Mutations in COL1A1 and COL1A2 genes affecting type I collagen.

Which type of dentinogenesis imperfecta is associated with osteogenesis imperfecta?

Type I.

Radiographically, how do teeth appear in regional odontodysplasia?

Poorly mineralised, enlarged pulp chambers giving a ‘ghost-tooth’ appearance.

What is the recommended treatment for regional odontodysplasia?

Extraction of affected teeth.

Define dentine dysplasia.

Hereditary condition producing ‘rootless’ teeth due to abnormal dentine formation.

List two disturbances of eruption timing.

Premature eruption, delayed eruption, impaction, ankylosed teeth.

What is internal resorption of the pulp?

Progressive resorption of dentinal walls from within the pulp chamber/canal.

Give two causes of external root resorption.

Trauma, orthodontic movement, cysts/tumors, impaction pressure.

Differentiate exogenous and endogenous tooth stains.

Exogenous: surface discoloration from external sources (foods, tobacco). Endogenous: intrinsic discoloration from systemic factors (tetracycline, bilirubin).

Which syndrome shows taurodontism together with amelogenesis imperfecta?

Hypomaturation-hypoplastic AI with taurodontism (autosomal dominant).

What is flexion in root morphology?

Mild bending of tooth root, less pronounced than dilaceration.

Which anomalous teeth may erupt after the permanent dentition (third dentition)?

Post-permanent supernumerary teeth (rare).

Name the syndrome combining cheilitis granulomatosa, facial paralysis and fissured tongue.

Melkersson-Rosenthal syndrome.

Which developmental lip disease predominantly affects males and shows everted, inflamed labial salivary glands?

Cheilitis glandularis.

How are palatal clefts classified when only the uvula is split?

Isolated cleft of the uvula.

Why is multidisciplinary care essential for cleft patients?

Because of combined cosmetic, feeding, speech, dental, and psychosocial issues.

Which arch relationship subdivision indicates unilateral mesial positioning of the mandibular arch?

Angle’s Class III subdivision (unilaterally mesial).

What oral finding is typical in hemifacial hypertrophy regarding tooth eruption timing?

Premature eruption of teeth on the affected side.

A patient has bilaterally enlarged jaws due to pituitary gigantism. Which jaw condition is this?

Macrognathia affecting both jaws.

Which trauma-related condition can lead to concrescence after eruption?

Post-eruption cemental fusion from trauma or overcrowding.

Name two local factors that can produce environmental enamel hypoplasia of a single developing tooth.

Local infection or trauma to the primary predecessor tooth.

Which developmental tooth anomaly resembles a small extra cusp on the occlusal surface of a premolar?

Dens evaginatus.

Describe an enamel pearl containing a pulp horn.

A nodule of enamel with an internal dentine core and pulp horn, often at molar furcations.

What is the effect of fluorosis on enamel development?

Ingestion of excessive fluoride causes environmental enamel hypoplasia with mottling and white/brown patches.

Why can dilacerated roots complicate endodontic therapy?

Severe curvature makes canal instrumentation and obturation difficult.

On which teeth is localized macrodontia (large single tooth) most common?

Mandibular third molars.

What is the usual clinical management of an asymptomatic enamel pearl?

No treatment unless it causes periodontal problems or is caries-prone.

Which developmental anomaly involves premature ankylosis of primary teeth?

Ankylosed teeth, leading to infra-occlusion and eruption disturbances of successors.

How does hypocalcified AI present clinically?

Yellow-brown, soft enamel that can be scraped away easily.

In which condition are blue sclerae and brittle bones seen alongside dentinogenesis imperfecta?

Osteogenesis imperfecta.

What type of mutation is thought to cause regional odontodysplasia?

Somatic mutation, possibly viral in origin.

Which teeth most commonly fail to develop in partial anodontia?

Third molars.

What is the typical radiographic finding of dentine dysplasia (‘rootless teeth’)?

Short or absent roots with abnormal pulp chambers.

List two risk factors for external chemical erosion of teeth.

Frequent citrus juice intake; gastric acid regurgitation in bulimia.

Describe the occlusal effect of mandibular prognathism.

Anterior cross-bite due to forward position of the mandible relative to maxilla.