15.2 Non-Surgical Periodontal Therapy and Maintenance Protocols

6.2 Non-Surgical Periodontal Therapy and Maintenance Protocols

Non-Surgical Periodontal Therapy (NSPT), anchored by Scaling and Root Planing (SRP), represents the foundational phase of periodontal care (Phase I therapy). Understanding the biological mechanisms of healing, mastering hand instrument selection, applying local and systemic pharmacotherapy, and adhering to strict re-evaluation and maintenance protocols are critical domains evaluated on the INBDE.

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Goals and Biological Healing of Scaling & Root Planing

Scaling is the removal of dental plaque biofilm, calculus, and stains from supra- and subgingival tooth surfaces. Root Planing is a definitive treatment procedure designed to remove rough cementum and dentin impregnated with calculus or contaminated with bacterial endotoxin (lipopolysaccharide / LPS).

Clinical Goals of SRP

1. Eradicate subgingival microbial biofilm and reduce pathogenic bacterial load.
2. Eliminate calculus deposits and toxic cementum to create a smooth, biologically acceptable root surface.
3. Reduce probing pocket depths, resolve clinical inflammation (BOP), and induce gain in clinical attachment.

Biological Healing Response Post-SRP

INBDE High-Yield Concept: Following SRP, periodontal healing occurs primarily through the formation of a Long Junctional Epithelium (LJE) extending along the root surface. SRP does NOT result in new connective tissue attachment (no new insertion of periodontal ligament fibers into newly formed cementum) or new alveolar bone formation.

• Soft Tissue Repair: Healing is characterized by connective tissue shrinkage (recession) and readaptation of the junctional epithelium to the root surface via hemidesmosomes, creating a tight epithelial seal (LJE).
• Probing Depth Reduction: Achieved through a combination of gingival recession (tissue contraction as inflammation resolves) and increased tissue resistance to probe penetration due to connective tissue collagen repair at the base of the pocket.

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Periodontal Hand Instrumentation

Mastery of curette geometry, blade angles, and site selection is frequently tested on the INBDE.

Universal vs. Gracey Area-Specific Curettes

Gracey Area-Specific Curette Selection Guide

• Gracey 1/2 & 3/4: Anterior teeth (incisors and canines, all surfaces).
• Gracey 5/6: Anterior teeth and premolars.
• Gracey 7/8 & 9/10: Posterior teeth, buccal (facial) and lingual surfaces.
• Gracey 11/12 & 15/16: Posterior teeth, mesial surfaces.
• Gracey 13/14 & 17/18: Posterior teeth, distal surfaces.

Working Stroke Technique: When adapting a Gracey curette, the lower shank must be parallel to the tooth surface being planed. This automatically aligns the $70^\circ$ offset working cutting edge at the ideal working angulation of $70^\circ$ to $80^\circ$ relative to the root surface.

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Pharmacotherapy: Local & Systemic Antimicrobials & Host Modulation

Antimicrobial therapy serves as an adjunct to mechanical SRP, never a replacement.

Systemic Host Modulation: Sub-Antimicrobial Dose Doxycycline

• Periostat (Doxycycline Hyclate 20 mg BID): Taken orally twice daily for 3 to 9 months. At this sub-antimicrobial dose, doxycycline does not exert antibacterial effects, does not induce bacterial resistance, and does not alter normal microflora. Instead, it acts via host modulation by inhibiting the activity of MMP-8 (collagenase), thereby down-regulating tissue destruction in chronic periodontitis.

Locally Delivered Sustained-Release Antimicrobials

Indicated as an adjunct to SRP in localized sites with persistent probing depths $\ge 5$ mm and bleeding on probing that have failed to resolve after initial SRP:

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Post-SRP Re-Evaluation Protocol

Re-evaluation is a mandatory step performed after Phase I therapy to assess treatment outcomes and dictate Phase II (surgical) or Phase IV (maintenance) care.

Timing of Re-Evaluation

INBDE High-Yield Rule: Re-evaluation must be performed 4 to 6 weeks after the completion of SRP.

• Biological Rationale: Epithelial repair (junctional epithelium) occurs within 1 to 2 weeks, but underlying connective tissue repair, collagen maturation, and spatial pocket repopulation require a minimum of 4 to 6 weeks. Re-evaluating prior to 4 weeks yields false positive signs of persistent inflammation due to incomplete tissue healing.

Parameters Evaluated at Re-Evaluation

1. Full-mouth periodontal probing depths (PD) and clinical attachment levels (CAL).
2. Presence of bleeding on probing (BOP) and suppuration.
3. Plaque scores and patient oral hygiene compliance.
4. Tooth mobility, furcation involvement, and mucogingival defects.

Clinical Decision Tree: Sites that exhibit resolution (PD $\le 4$ mm without BOP) transition to Periodontal Maintenance. Sites with persistent deep pockets (PD $\ge 5\text{--}6$ mm) with active BOP require Phase II surgical therapy or targeted re-treatment.

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Periodontal Maintenance (Phase IV Recall)

Periodontal maintenance is an ongoing lifelong therapy tailored to prevent disease recurrence in treated periodontitis patients.

Recall Interval Rationalization

Standard Recall Interval: 3 months (90 days) is the gold-standard maintenance interval for treated periodontitis patients.

• Microbiological Basis: Subgingival debridement dramatically reduces pathogenic bacteria. However, studies demonstrate that subgingival pathogens (particularly Red Complex anaerobes such as P. gingivalis and T. denticola) repopulate deep pockets and return to baseline pre-treatment levels within 90 to 120 days post-SRP. A 3-month recall interval disrupts this repopulation cycle before pathogenic thresholds trigger renewed tissue destruction.