1. Selection of treatment techniques
   1. Angular defects are classified on the no. Of walls remaining A) One walled defect B) Two walled defect C) Three walled defect
   2. One-wall angular defects : Needs surgical recountouring
      1. T/t : Ramping
   3. Three-wall defects (particularly if they are narrow & deep) : New attachment & Bone reconstruction
      1. Note: Deep & Narrow defect has the best prognosis
   4. Two-wall : can be treat with either method depending on their depth, width, & general configuration
   5. Karn et al classification -1984 To describe irregular defects
      1. 1. Craters: Involves only one side ( 2 wall defect & most common)
         1. Note: To treat crater maximum amount of interdental bone is to be removed
      2. 2. Trench: Involves 2 or 3 sides
      3. 3. Moat: Involves 4 sides ( Circumferential defect)
   6. Wall/ Bone defect are checked by Bone Sounding/ Transgingival probing
2. Resective osseous surgery
   1. Vertical grooving
      1. Festooning - Reduce buccal & lingual thickness of bone interdentally
      2. Indication : Shallow craters, thick bony ledges
   2. Radicular Blending
      1. For thicker, heavier bone after vertical grooving
      2. Indication : Shallow craters, thick ledges
   3. Flattening Interproximal Bone
      1. Removal of small amount of supporting bone
      2. One walled Interproximal defects/ hemisepta
      3. Three walled defect- Coronally placed one wall edge
      4. Contraindicated : Large hemiseptal defects
   4. Gradualizing Marginal bone
      1. Removal of bony discrepancies - Widow’s peaks
3. Root Bio Modification
   1. A procedure by which all the toxins from the root surface are removed
      1. So chances of new attachment increases
   2. Materials used
      1. 1.Citric Acid can be used : Urist Ph = 1 & applied for 2-5 mins Helps in Reattachment of fibres
      2. 2. Fibronectin
      3. 3. Tetracycline
      4. 4. 25% EDTA
      5. 5. Conc. HCl
4. GTR ( Guided Tissue Regeneration)
   1. Given by : Nyman, Linde, Karring, Gotlow
   2. It is use of Barrier membrane to prevent epithelial cells to come to the area of defect.
      1. It allows the CT cells to come to the area of defect first & form bone
   3. Barrier Membrane
      1. Resorbable
         1. 1) Resorb Mac 2) Osseoquest —> Polyglycolic + Polylactic + Trimethylene carbonate 3) Bioguide —> Bilayer porcine derived collagen 4) Atrisorb —> Polylactic acid gel 5) Biomend —> Bovine Achillis tendon collagen 6) Autologous Periosteum from palate
      2. Non Resorbable
         1. First Barrier membrane used was PTFe ( Polytetra fluoro ethylene) , marketed as Millipore
5. Osseous surgery
   1. Father of osseous surgery : Schluger
   2. 2 Types
      1. Additive
         1. Bone grafts
         2. GTR
      2. Resective
         1. Osteoplasty
            1. Reshaping of the alveolar process to achieve a more physiological form without removal of supporting bone, includes 1) Vertical grooving 2) Radicular Blending
         2. Ostectomy
            1. Bone from attachment apparatus is removed to establish gingival contours that will be maintained 1) Flattening of interproximal Bone 2) Gradualizing Marginal Bone
   3. Architecture of bone
      1. Positive
         1. Interdental bone is present at higher level than interradicular
      2. Negative / Reverse
         1. Interdental bone is at lower level than Interradicular bone
      3. Flat
         1. Interdental & Interradicular bone are at same level
      4. Ideal