LDS Part 1 flashcards

31 cards. Read the term and the definition here. The deck at the top of this page is optional.

FDI tooth numbering

A two-digit system: the first digit denotes the quadrant (1–4 for upper right, upper left, lower left, lower right), and the second digit denotes tooth position 1–8 from the midline.

Enamel inorganic content

Mature enamel is approximately 96% inorganic hydroxyapatite by weight, with about 1% organic material and 3% water, making it the most highly mineralized dental tissue.

Dentin composition

Dentin is roughly 70% inorganic hydroxyapatite, 20% organic material (predominantly type I collagen), and 10% water by weight, giving it greater elasticity than enamel.

Zinc phosphate cement setting

An acid–base reaction between zinc oxide powder and phosphoric acid liquid; the reaction is exothermic, and the freshly set cement is acidic and can irritate the pulp.

Glass ionomer adhesion

Glass ionomer cements bond chemically to enamel and dentin through carboxylate groups and release fluoride over time, but they are moisture-sensitive during the initial setting phase.

Polymerization shrinkage

Composite resins contract during curing, creating marginal stress and microleakage; incremental layering and low-shrinkage or bulk-fill formulations reduce this effect.

High-copper amalgam

Amalgam containing more than about 6% copper; it reduces the weak gamma-2 (Sn7-8Hg) phase, improving strength and corrosion resistance compared with low-copper alloys.

Crown-to-root ratio

The ratio of clinical crown length to root length supported by bone; a 1:1 ratio is minimally acceptable for single-rooted teeth, and 2:1 is favorable for multi-rooted support.

PMMA denture base

Polymethyl methacrylate is the standard denture base resin; heat-cured forms are common, and processing shrinkage is managed by injection molding or extended curing cycles.

Dental ceramic flexural strength

Feldspathic porcelain has low flexural strength and is used for veneers; zirconia and lithium disilicate have higher strength and are used for crowns and bridges.

Lichen planus oral features

A T-cell–mediated interface mucositis; reticular Wickham striae are most common, while erosive and atrophic forms are symptomatic and carry a small malignant transformation risk.

Leukoplakia definition

A clinical diagnosis of exclusion for a white patch not attributable to another cause; non-homogeneous lesions and those on the floor of the mouth carry higher malignant transformation risk.

Radicular cyst

The most common odontogenic cyst, arising from epithelial rests of Malassez in a periapical area after pulp necrosis; it presents as a periapical radiolucency and requires endodontic or surgical treatment.

Dentigerous cyst

An odontogenic cyst that surrounds the crown of an unerupted tooth and attaches at the cementoenamel junction; it is the second most common odontogenic cyst.

Odontogenic keratocyst

A cyst with a parakeratinized lining and high recurrence rate, associated with PTCH1 mutations and nevoid basal cell carcinoma syndrome; it often grows along the mandible without expansion.

Ameloblastoma

A locally aggressive benign odontogenic tumor, most common in the posterior mandible, showing a soap-bubble multilocular radiolucency; wide resection is often required because of high recurrence.

Oral squamous cell carcinoma

The most common oral malignancy; risk factors include tobacco and alcohol (synergistic), betel quid, and HPV-16; common sites are the lateral tongue and floor of the mouth.

Wickham striae

Fine white lacy lines on the oral mucosa that are characteristic of reticular oral lichen planus and are typically asymptomatic and bilateral.

Inferior alveolar nerve block

An injection targeting the pterygomandibular space near the mandibular foramen; failure commonly results from accessory innervation, a bifid canal, or deposition too anteriorly.

Infective endocarditis prophylaxis

Antibiotic prophylaxis before invasive dental procedures is recommended for high-risk cardiac conditions such as prosthetic valves, prior endocarditis, and certain congenital heart disease.

Periapical granuloma

A chronic periapical inflammatory lesion of granulation tissue arising after pulp necrosis; it is the most common periapical lesion and is distinguished from a cyst only histologically.

Trismus

Limited mouth opening, often defined as interincisal opening less than about 35–40 mm; common causes include muscle spasm, infection, and temporomandibular joint disorders.

Ludwig angina

A rapidly spreading cellulitis of the submandibular, sublingual, and submental spaces, usually of odontogenic origin; it threatens the airway and requires urgent surgical drainage and antibiotics.

Dry socket

Alveolar osteitis occurring after tooth extraction, with loss of the blood clot and severe pain; risk is reduced by atraumatic technique and by avoiding smoking postoperatively.

Caries progression

Demineralization occurs when plaque pH falls below the critical pH of about 5.5 for enamel; remineralization occurs when pH recovers, and net loss determines lesion progression.

Fluoride mechanism

Fluoride promotes remineralization, forms fluorapatite with lower solubility, and inhibits bacterial enolase; topical exposure is more important than systemic ingestion for caries prevention.

Dental erosion

Irreversible loss of tooth structure by chemical dissolution not involving bacteria; intrinsic acid from reflux or vomiting and extrinsic dietary acids are common causes.

Periodontal disease classification

Current classification uses staging (severity and complexity) and grading (progression rate), replacing the older 1999 system that used chronic and aggressive periodontitis categories.

Necrotizing ulcerative gingivitis

An acute infection causing punched-out interdental papillae, pain, bleeding, and fetor oris; it is associated with stress, poor hygiene, and immunosuppression and is treated with debridement and metronidazole.

Bisphosphonate osteonecrosis

Exposed bone in the maxillofacial region persisting more than 8 weeks in a patient on antiresorptive therapy without radiation history; prevention focuses on avoiding elective extractions.

Pulpitis types

Reversible pulpitis causes brief pain to stimuli and resolves on removal; irreversible pulpitis causes spontaneous or lingering pain and requires endodontic treatment or extraction.