Several minimal invasive techniques have been proposed since the last decade aiming to enhance and provide adequate environment for periodontal regeneration. Harrel and Rees proposed minimally invasive surgery (MIS) in 1995 and minimal invasive surgical technique (MIST) that was introduced in 2007 and then further enforced with modified minimally invasive surgical technique (M-MIST) in 2009 . A new minimal invasive technique called Non-Incised Papilla Surgical Approach (NIPSA) was introduced in 2017. It is aims to maintain the marginal tissues integrity by placing horizontal or oblique incision apical to the defect approaching the defect through apical access.

Intraosseous vertical defects are one of the consequences that could result from periodontitis, which are classified according to their architecture by the number of residual walls, defect width as well as topographic extension in relation to the tooth.

Conventional surgery done for regenerative purpose regarding vertical defects has been known to be affected by clot stability, it was reported in the literature that reduced clinical outcomes occurred when early wound failure and exposure of the treated area occurred. This led to the innovation of different minimally invasive flap techniques that aimed at reducing the surgical trauma, allowing blood clot stability, protecting the regenerating site, reducing patient discomfort postoperatively as well as minimizing surgical chair time Among these techniques are papilla preservation flaps and minimally invasive surgical approaches with papilla elevation or without papilla elevation . However, these techniques had in their design incisions related to the interdental papilla which would jeopardize and complicate the vascular integrity of the interdental tissues Non incised Papilla surgical approach is a new surgical technique introduced by Moreno Rodriguez in 2017 to maintain the marginal tissues and the papilla intact by placing a horizontal or oblique incision apical to the defect and approaching it through an apical access leaving the marginal tissues to act as a "dome " protecting the blood clot

Inclusion Criteria:

• Patients with Stage III periodontitis patient having at least one tooth with two wall or combined two to three walled intraosseous defect more than or equal 3 mm deep (assessed by trans-gingival probing, radiographic examination) with clinical attachment level (CAL) more than or equal 5mm and pocket depth (PD) more than or equal 6 mm.
• Defect not extending to a root furcation area.
• Vital teeth
• No history of intake of antibiotics or other medications affecting the periodontium in the previous 6 months.
• No surgical periodontal therapy carried out in the past 6 months.
• Able to sign an informed consent form.
• Patients who are cooperative, motivated, and hygiene conscious.
• Able to come for the follow up appointment's needed.

Exclusion Criteria:

• Any systemic disease that contra-indicates periodontal surgery or may affect healing.
• Smokers
• Pregnant females
• Drug abusers

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single blinded