World Workshop, 2017, defined Periodontitis as a chronic multifactorial inflammatory disease, characterized by progressive destruction of the tooth-supporting apparatus, associated with dysbiotic plaque biofilms. A WHO survey conducted in India, along with four other countries, observed a 100% prevalence of periodontal disease (including gingivitis) in adults in India. Periodontitis was found to start after age 15 and at 17 years, 10% of Indian boys had periodontitis. The most prevalent form of bone defect seen in individuals with periodontitis is horizontal bone loss which is also regarded as the least favorable for periodontal regeneration. Patients with horizontal bone abnormalities still have no practical choice except to use an access flap for pocket depth reduction. The purpose of periodontal flap surgery is to increase the visibility and accessibility of the underlying bone and root surfaces which will enable surgeons to carry out regenerative procedures and reduce disease activity. Numerous studies have shown that the improved visual acuity obtained from using an operating microscope improves field illumination with specially made microsurgical instruments enable more precise and non-traumatic manipulation of both soft and hard tissues. It enhances surgical access and prevents the needless removal of tissue, optimize defect debridement and root instrumentation, improve vascularization and increase flap mobility. It also increases the likelihood of achieving better primary wound closure. The use of traditional techniques for access flaps has drawbacks such as gingival recession, exposed root surfaces and opening of gingival embrasures which can result in the formation of black triangles and an unsightly appearance. Operating microscopes are integral to achieving the 

advantages of periodontal microsurgery. These benefits including illumination, magnification and refined surgical skills collectively called the magnification triad are crucial for performing esthetic periodontal plastic surgeries to obtain exemplary and complex details in small scale. All operations performed under magnification beginning at 2.5x and employing an operating microscope or dental loupes are included in periodontal microsurgery. The goal of minimally invasive surgery which was first presented by Harrel and Rees in 1995, is to carefully treat the hard and soft tissues, leave as few scars as possible on the flap and reduce the amount of wound that remains after surgery. The use of smaller more accurate surgical procedures made possible by using magnification instruments like operating microscopes as well as microsurgical instruments and materials is referred as "minimally  

invasive surgery". Operating microscope usage in periodontal regenerative surgery was suggested by Cortellini and Tonetti who noted improved initial wound closure potential from an average of 70% of cases acquired with regular surgery to an exceptional 92% attained with microsurgery. This study is intended to assess and compare the clinical and radiographic efficacy of conventional and microsurgical access flap for the treatment of horizontal bone defects in patients with periodontitis taking into account the findings of the previously stated literature. The null hypothesis is that no significant difference exists between the conventional and microsurgical access flap technique in 

managing horizontal bony defect in periodontitis patients.