This study is aiming to compare the clinical and radiographic outcomes after complete versus incomplete removal of granulation tissue during modified minimally invasive surgical technique for management of periodontal intrabony defects in patients with chronic periodontitis.

Periodontal surgery has been expanding in the world of dentistry throughout the past years, as new techniques are emerging to treat the different and complex periodontal disorders. Surgical procedures in dentistry have undergone major changes to minimize invasiveness. In addition, novel instruments and materials have been made to suit the evolution of the surgical procedures (Cortellini. 2012).

Teeth with deep pockets associated with deep intra-bony defects are a clinical challenge for periodontists, where periodontal regeneration has been proven to be effective in managing the treatment of one-, two-, and three-wall intra-bony defects (Needleman and Tucker 2012;Needleman. 2015).

Harrel and Rees (1995) were the first to introduce the term minimally invasive surgery (MIS). MIS is used to describe the use of smaller and more precise surgical procedures that are possible by using of magnifying instruments, such as operating microscopes and microsurgical instruments and materials (Cortellini. 2012).

The rationale for the development of minimally invasive surgical technique (MIST) includes: reduction of trauma during the surgery, increase in flap and wound stability, improvement of wound primary closure, reduction of surgical time, and minimization of intra-operative and post-operative patient discomfort (Cortellini. 2007).

With the use of MIST, Cortellini and Tonneti (2009) confirmed blood clot protection with the aspects of wound and blood clot stability and primary wound closure.

An enhancement of MIST, the modified minimally invasive surgical technique (M-MIST), has been introduced by Cortellini in 2009 to further reduce the surgical invasiveness, with three major objectives in mind: (1) minimize the interdental tissue tendency to collapse providing space provision for regeneration, (2) enhance the wound/soft tissue stability and (3) reduce patient morbidity.

Some authors evaluated the use of various regenerative material in MIST and M-MIST e.g. Enamel matrix derivative (Cortellini 2007) PDGF-bb (Cosyn et al. 2012) and collagen enriched bovine derived xeno-graft (Mishra et al., 2013). Cortellini (2011) also, noted that the use of regenerative material is not necessary with M-MIST.

Hung et al, (2012) reported that granulation tissue could contain progenitor stem cells which are very important components needed for periodontal tissue regeneration.

Moreover, Park et al. (2011) assumed that the inflamed granulation tissue could be used to regenerate lost tissues in the same individual in other defective sites according to its regenerative potential.

All the previous data raised an important question about the necessity to remove granulation tissues in periodontal regenerative techniques: Is complete removal of granulation tissue in M-MIST is mandate for treating isolated intra-bony defects for better healing?

Inclusion Criteria:

• - systemically healthy patients
• Age range from 25 - 55.
• Patients with moderate to advanced chronic periodontitis with pockets ≥ 5 mm 6-8 weeks after phase I (non-surgical) therapy.
• Vertical 2 or 3 walls Intra-bony defects.
• Perform and maintain good oral hygiene.
• Able to come for the follow up appointment's needed

Exclusion Criteria:

• - Smokers.
• Pregnant patients.
• patients with poor oral hygiene.
• Multirooted teeth with furcation involvement.