The aim: Clinical and Radiographic Evaluation for intra-osseous defects in stage III periodontitis using NIPSA versus M-MIST Steps in short Pre-surgical therapy

• Before surgical intervention, each patient will be given careful instructions on proper oral hygiene measures.

Surgical Procedures:

• Group B (Control): Patients will receive Modified Minimally Invasive Surgical technique (M-MIST) Group A (Test): Patients will receive Non-Incised Papilla Surgical Approach (NIPSA) Postoperative medication
• Administration of amoxicillin (500 mg tabs) T.I.D for 7 days and Metronidazole (500 mg tabs) T.I.D for 7 days
• Rinsing with Chlorhexidine 0.12% (B.I.D for 14 days).
• Ibuprofen 600 mg tabs once every 8h could be administrated in case of unbearable pain
• Follow up period: after 8 weeks/ after surgery by 1 week- 1 month- 3 months- 6 months- 1 year

P: Population: Stage III periodontitis presenting intraosseous defects I: Intervention: Non-Incised Papilla Surgical Approach (NIPSA) C: Control: Modified Minimally Invasive Surgical Technique (M-MIST) O: Outcome measurements T: 1- year S: Randomized clinical trial

Surgical Procedures:

The operator will anesthetize the surgical sites with 4% ARTINIBSA containing Articaine hydrochloride Epinephrine (adrenaline) 1: 100.000 injection for both groups. For patients that recieved (NIPSA) as reported by (Moreno Rodríguez and Caffesse 2017).

• After locally anesthetizing the area an apical horizontal incision on the buccal mucosa, as far as possible from the interdental papillae and marginal KT will be performed. Soft tissue will be reflected apico-coronally by a full-thickness flap showing the granulation tissue filling the bony defect after exposing the coronal limit of the intra-bony component of the defect, while the marginal tissue will be kept unaltered.
• Horizontal mattress sutures with single interrupted sutures will be placed as the second line of closure.

while patients that received (M-MIST) reported by (Banthia et al. 2016a)

• Access to the defect will be gained through the tiny buccal triangular flap: from the buccal 'window' the soft tissue filling the defect (i.e. the so-called granulation tissue) will be sharply dissected from the papillary supra-crestal connective tissue and from the bony walls with a micro-blade and will be removed with a mini-curette (The soft tissue will be sharply dissected from the osseous defect)
• No interdental and/or lingual intra-sulcular incisions will be performed. The supra-crestal interdental tissues.
• Surgical flaps will be sutured to the pre-surgical level with 5-0 vicryl suture utilizing single interrupted suturing techniques that will achieve primary closure.
• Sutures will be removed 2 weeks post-surgically. Patients will be asked to discontinue mechanical tooth-brushing technique in the surgical area for 2 weeks.
• After this period, patients will be instructed to continue mechanical tooth brushing again of the treated sites using a soft toothbrush.

Patients will be recalled monthly for supportive periodontal therapy during the course of the study. And then will be recalled every six months for supportive periodontal therapy after the study.

Inclusion Criteria:

• Stage III periodontitis patient having at least one tooth with Two walls or combined 2- to 3-walls intraosseous defects ≥ 3 mm deep (assessed by trans-gingival probing, radiographic examination) with clinical attachment level (CAL) ≥ 5mm and pocket depth (PD) ≥ 6 mm.
• Defect not extended to a root furcation area.
• Vital teeth
• Non-smokers.
• No history of intake of antibiotics or other medications affecting the periodontium in the previous 6 months.
• No periodontal therapy carried out in the past 6 months.
• Able to sign an informed consent form.
• Patients age between 20 and 60 years old.
• Patients who are cooperative, motivated, and hygiene conscious.
• Able to come for the follow up appointment's needed.
• Systemically free according to Modified Cornell Medical Index health questionnaire (Kark et al., 1964).

Exclusion Criteria:

• Pregnancy or breast feeding.
• The presence of an orthodontic appliance.
• Teeth mobility greater than grade I.

Single blinded:

• Blinding of the participants is not applicable.
• Blinding of the operator is not applicable.
• Outcome assessor (primary and secondary outcomes) & biostatistician will be blinded.