Iran Dental Specialty Board - Periodontics flashcards

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

Junctional epithelium

Nonkeratinized epithelium that attaches to the tooth via hemidesmosomes and internal basal lamina, forming the epithelial seal; it is 15–30 cell layers coronally and 1–3 apically.

Biologic width

The supracrestal attachment unit comprising junctional epithelium and connective tissue attachment, approximately 2 mm total; restorative margins should not encroach on it.

Transseptal fibers

Gingival fiber group running from cementum of one tooth to the cementum of the adjacent tooth; it regenerates earliest after periodontal surgery.

Oblique fibers

The most numerous principal fibers of the periodontal ligament, running from cementum apically to bone coronally; they resist axial occlusal forces.

Keystone pathogen

A low-abundance organism such as Porphyromonas gingivalis that dysregulates the host immune response and reshapes the microbiome, driving dysbiosis rather than causing damage by bulk.

Gingipains

Cysteine proteases produced by P. gingivalis that cleave complement C3 and C5, degrade immunoglobulins, and promote tissue destruction and dysbiosis.

RANKL/OPG ratio

Ratio of receptor activator of NF-κB ligand to osteoprotegerin; a high ratio favors osteoclastogenesis and alveolar bone loss in periodontitis.

Clinical attachment level

Probing depth plus gingival margin recession measured from the cementoenamel junction; it is the reference measure of periodontal attachment loss.

Bleeding on probing

Presence of bleeding at a probed site, recorded at six sites per tooth; full-mouth BOP below 10% is consistent with periodontal stability.

Grade C periodontitis

Rapid progression category with bone loss/age ratio above 1.0, or heavy smoking (≥10 cigarettes/day), or HbA1c ≥7.0% in a patient with diabetes.

Stage III periodontitis

Severe periodontitis with CAL ≥5 mm, radiographic bone loss to the middle third of root, and ≤4 teeth lost; complexity factors may include furcation or vertical defects.

Subgingival instrumentation

Mechanical debridement of biofilm and calculus from root surfaces; it produces mean CAL gain of about 0.5–1.0 mm in deep pockets and reduces bleeding.

Amoxicillin plus metronidazole

Adjunctive systemic antibiotic regimen (500 mg each, three times daily for 7 days) reserved for Grade C or Stage III–IV periodontitis; it adds modest CAL gain.

Sub-antimicrobial doxycycline

Low-dose doxycycline (20 mg twice daily) that inhibits matrix metalloproteinases; used as host modulation adjunct, not as primary therapy.

Open flap debridement

Surgical elevation of a flap for access to deep pockets; it reduces probing depth more than scaling and root planing but adds little attachment gain.

Apically positioned flap

Flap surgery that moves the gingival margin apically to eliminate pseudopockets and preserve keratinized tissue; it often causes recession and root sensitivity.

Crown lengthening

Resective procedure that removes soft tissue and bone to re-establish about 3 mm of supracrestal attachment; used for biologic width violation or esthetic crown lengthening.

Guided tissue regeneration

Barrier membrane technique that excludes epithelium and allows periodontal ligament and bone cells to repopulate the defect; best outcomes in deep narrow intrabony defects.

Enamel matrix derivative

Amelogenin-based protein gel that promotes periodontal ligament regeneration; meta-analyses show attachment gain similar to guided tissue regeneration in intrabony defects.

Coronally advanced flap

Flap design for root coverage that advances the gingival margin coronally over the denuded root; combined with a connective tissue graft it is the reference standard.

Peri-implant mucositis

Reversible inflammation confined to the soft tissue around an implant, with bleeding on probing but no progressive bone loss; treated by debridement and improved plaque control.

Peri-implantitis

Inflammation of peri-implant tissues with bleeding, increasing probing depth, and progressive radiographic bone loss beyond initial crestal remodeling; treatment requires surface decontamination.

Platform switching

Use of a smaller-diameter abutment on a wider implant platform; it shifts the inflammatory infiltrate medially and reduces crestal bone loss.

Bidirectional link

The mutual relationship between periodontitis and systemic disease, best established for diabetes, where hyperglycemia worsens periodontitis and therapy modestly lowers HbA1c.

MRONJ

Medication-related osteonecrosis of the jaw, associated with bisphosphonates and denosumab; management is conservative and elective surgery should be deferred in high-risk patients.

Drug-induced gingival overgrowth

Gingival enlargement caused by phenytoin, cyclosporine, or calcium channel blockers; managed with plaque control and possible drug substitution.

Treatment plan sequence

Emergency care, cause-related therapy, reevaluation, corrective therapy, and maintenance; each phase is a decision point before proceeding to the next.

Endodontic-periodontal lesion

Combined lesion involving both pulp and periodontium; true combined lesions have a poor prognosis, while primary endodontic lesions often heal after root canal therapy.

Sensitivity

Proportion of truly diseased patients who test positive, calculated as true positives divided by true positives plus false negatives; it is prevalence-independent.

Specificity

Proportion of truly healthy patients who test negative, calculated as true negatives divided by true negatives plus false positives; it is prevalence-independent.

Intention-to-treat analysis

Analysis that includes all randomized participants in their assigned groups regardless of adherence; it preserves the benefits of randomization and reduces bias.

Periodontal risk assessment

Tool combining bleeding on probing, probing depth, tooth loss, bone loss, systemic factors, and smoking to estimate risk and set recall intervals.