BDS Periodontology Syllabus

What is the goal and mechanism of non-surgical periodontal therapy (scaling and root planing)?

To remove supra- and subgingival plaque, calculus, and endotoxin-laden cementum, disrupting the biofilm to resolve inflammation and allow reattachment/long junctional epithelium formation. It reduces probing depth and bleeding on probing.

What probing depth threshold is often cited as the limit of effective closed root planing efficiency?

Instrumentation efficacy declines markedly in pockets deeper than $5\ \text{mm}$; residual calculus increases substantially in pockets $>5\text{–}6\ \text{mm}$, favoring surgical access.

What is the role of systemic sub-antimicrobial dose doxycycline (SDD) in periodontal therapy?

At $20\ \text{mg}$ twice daily it acts as a host-modulating agent by inhibiting matrix metalloproteinases (collagenase), reducing tissue breakdown without an antibacterial effect.

List the main goals of periodontal surgical therapy.

Gain access to root surfaces for debridement, reduce/eliminate pockets, correct mucogingival and osseous defects, regenerate lost periodontal tissues, and facilitate maintenance and plaque control.

Differentiate gingivectomy from a flap procedure.

Gingivectomy excises and removes pocket wall tissue (suprabony pockets, healing by secondary intention), indicated for fibrotic overgrowth. A flap reflects tissue to gain access, is repositioned and sutured (heals by primary intention), and preserves keratinized tissue and treats infrabony defects.

What is guided tissue regeneration (GTR) and its underlying biological principle?

GTR uses a barrier membrane to exclude fast-growing epithelial and gingival connective tissue cells, allowing PDL and bone cells to selectively repopulate the root surface and form new attachment (new cementum, PDL, and bone).

Which osseous defect morphology has the best regenerative prognosis with GTR/grafting?

Three-wall intrabony (infrabony) defects and narrow deep two-wall defects, because more surrounding bony walls provide a better source of regenerative cells and space maintenance.

What wavelengths do common dental lasers use, and which is well absorbed by water/hydroxyapatite?

Diode ($810\text{–}980\ \text{nm}$) and Nd:YAG ($1064\ \text{nm}$) are absorbed by pigment/soft tissue; Er:YAG ($2940\ \text{nm}$) and Er,Cr:YSGG ($2780\ \text{nm}$) are highly absorbed by water and hydroxyapatite, allowing hard-tissue/calculus ablation. $\ce{CO2}$ ($10600\ \text{nm}$) is a soft-tissue laser.

What does the LANAP protocol stand for and use?

Laser-Assisted New Attachment Procedure, an FDA-cleared free-running pulsed Nd:YAG protocol used for regenerative periodontal treatment without conventional flap surgery.

What are claimed advantages of laser therapy in periodontics?

Bactericidal effect, selective removal of diseased epithelium, hemostasis, reduced bacteremia, minimal anesthesia, and reduced post-operative pain/swelling; adjunctive to scaling and root planing.

What is supportive periodontal therapy (SPT/maintenance) and its typical recall interval?

Periodic professional care after active therapy to prevent recurrence: reassessment, reinforcement of oral hygiene, and re-instrumentation. Typical recall interval is every $3\ \text{months}$, adjusted to risk.

According to Axelsson & Lindhe, what happens to teeth without maintenance after active periodontal therapy?

Without regular supportive periodontal therapy, patients experience recurrent disease and significantly greater attachment/tooth loss; maintenance patients retained attachment over 6+ years.

What is the proposed biological link between periodontitis and cardiovascular (atherosclerotic) disease?

Periodontal pathogens (e.g., P. gingivalis) and their endotoxins enter the circulation, promoting systemic inflammation (raised CRP, IL-6), endothelial dysfunction, and atheroma formation; bacterial DNA has been found in atherosclerotic plaques.

Describe the bidirectional relationship between diabetes mellitus and periodontitis.

Diabetes (especially poorly controlled) increases risk/severity of periodontitis via advanced glycation end-products (AGEs), impaired neutrophil function, and altered collagen metabolism. Conversely, periodontal inflammation worsens glycemic control (insulin resistance); periodontal therapy can lower HbA1c by roughly $0.3\text{–}0.4\%$.

Why is periodontitis considered the "sixth complication" of diabetes mellitus?

Loe (1993) described periodontal disease as the sixth complication of diabetes, alongside retinopathy, nephropathy, neuropathy, macrovascular disease, and impaired wound healing, because diabetics show markedly higher prevalence and severity.

What are the periodontal changes seen in pregnancy and their hormonal basis?

Pregnancy gingivitis and localized pregnancy "epulis" (pyogenic granuloma) due to elevated estrogen and progesterone increasing gingival vascularity, permeability, and favoring anaerobes like Prevotella intermedia. Peaks in the third trimester.

What is the proposed association between maternal periodontitis and adverse pregnancy outcomes?

Periodontitis is a possible risk factor for preterm birth and low birth weight, via prostaglandin/cytokine (PGE2, TNF-alpha, IL-1beta) mediated effects and possible bacterial translocation, though evidence that treatment improves outcomes is inconclusive.

How is periodontal disease linked to respiratory diseases?

Oral biofilm is a reservoir for respiratory pathogens; aspiration of periodontal/oral bacteria can cause or aggravate aspiration pneumonia and COPD, especially in ventilated or elderly/institutionalized patients. Oral hygiene reduces nosocomial pneumonia risk.

What is the difference between peri-implant mucositis and peri-implantitis?

Peri-implant mucositis is reversible inflammation of soft tissue around an implant WITHOUT bone loss (analogous to gingivitis). Peri-implantitis includes progressive supporting BONE loss around an osseointegrated implant (analogous to periodontitis).

Define osseointegration (Branemark).

A direct structural and functional connection between ordered, living bone and the surface of a load-bearing implant, without intervening fibrous (connective) tissue at the light-microscopic level.

What is the difference between the tooth and implant soft-tissue interface regarding fibers?

Around teeth, PDL and gingival collagen fibers insert perpendicularly into cementum. Around implants there is no PDL or cementum; supracrestal collagen fibers run parallel/circular to the implant surface, giving a weaker soft-tissue seal.

What minimum inter-implant and implant-to-tooth distances help preserve interproximal bone/papilla?

Maintain at least $\approx 3\ \text{mm}$ between adjacent implants and $\approx 1.5\text{–}2\ \text{mm}$ between an implant and a natural tooth to minimize crestal bone loss and papilla loss.

What is periodontal plastic (mucogingival) surgery, and name a common indication.

Surgical procedures to correct defects in morphology, position, and/or amount of gingiva/mucosa around teeth and implants. A common indication is root coverage of gingival recession; others include increasing keratinized tissue, ridge augmentation, and crown lengthening.

What is the Miller classification of gingival recession (Class I–IV)?

Class I: recession not extending to mucogingival junction (MGJ), no interdental loss (100% coverage expected). Class II: extends to/beyond MGJ, no interdental loss (100% coverage). Class III: interdental bone/soft-tissue loss, partial coverage. Class IV: severe interdental loss, no coverage expected.

What is the gold-standard procedure for root coverage of a single recession defect?

The subepithelial connective tissue graft (SCTG), typically combined with a coronally advanced flap, because it provides predictable root coverage and good color/blend.

Differentiate a free gingival graft from a connective tissue graft in purpose.

A free gingival graft (epithelialized palatal graft) is primarily used to INCREASE the width of keratinized/attached gingiva. A connective tissue graft (subepithelial) is preferred for ROOT COVERAGE with superior esthetics.

What is the coronally advanced flap (CAF), and what modification improves esthetics?

A flap coronally repositioned to cover an exposed root; combining it with a subepithelial connective tissue graft (CAF + SCTG) improves root coverage predictability and long-term stability.

What defines periodontal microsurgery and its main clinical benefit?

Periodontal surgery performed under magnification (surgical microscope/loupes, typically $\geq 10\times$) with microsurgical instruments and fine sutures ($7\text{-}0$ to $9\text{-}0$). Benefits: improved precision, primary closure, better wound healing, less trauma, and enhanced esthetics/root-coverage outcomes.

How does magnification level relate to microsurgical precision (approximate ranges)?

Loupes provide about $2\times\text{–}6\times$; the surgical operating microscope provides roughly $4\times\text{–}25\times$. Higher magnification improves visualization of tissue margins and passive, tension-free wound approximation.

What is the periodontal screening index PSR, and what does a code of 3 or 4 indicate?

Periodontal Screening and Recording uses a WHO probe divided into sextants (codes 0–4). Code 3 indicates a pocket $3.5\text{–}5.5\ \text{mm}$ (colored band partly visible); Code 4 indicates a pocket $>5.5\ \text{mm}$ (colored band disappears), requiring comprehensive assessment.

What is the difference between a suprabony and an infrabony (intrabony) periodontal pocket?

In a suprabony pocket the base of the pocket is CORONAL to the alveolar crest (horizontal bone loss pattern). In an infrabony pocket the base is APICAL to the crest, lying within a bony defect (vertical/angular bone loss).