## 4 Discussion
This gain in the resolution of osseous defects is attributed to characteristics of the resorbable membrane such tissue integration, cell occlusivity, clinical manageability, space making, and biocompatibility. The evaluation period of six months was frequently used because that is the most usual time frame in most clinical studies to evaluate the outcomes of regenerative periodontal surgery. In this systematic review, a time range of 6-12 months was preferred rather than a particular month. A subgroup analysis was performed based on the follow-up period. A subgroup analysis based on the type of membranes used was not possible because of a lack of studies which directly compared resorbable with non-resorbable membranes. The subgroup analysis of pocket probing depth shows a significant result (\(p\leq 0.00001\)) at all-time intervals (6-12 months) in the split mouth study group favoring the non-resorbable membrane group. A sensitivity analysis was carried out by removing studies lying outside the funnel plot (Figure A1 in Appendix A) to find no change in the effect estimate for all clinical parameters. While treating advanced intra-bony periodontal defects, the GTR membrane along with grafting materials showed better outcomes. [PERSON] et al. [42] in 2021 treated the intrabony defects with GTR membrane (control group) and the GTR membrane along with grafting material (observational group). Six months after surgery, there was no significant difference in PLI and SBI scores between the two groups (\(p\leq 0.05\)). The gingival cosmetic scores of the two groups of patients were higher than those before surgery. The observation group was higher than the control group (\(p\leq 0.05\)). Another retrospective study by [PERSON] et al. [43] in 2015 evaluated the efficacy of the resorbable GTR membrane along with deproteinized bone xenografts and compared it with the combination of enamel matrix derivative and deproteinized bone xenografts in aggressive periodontitis patients. The authors of the abovementioned study found that both GTR and EMD groups of treatment resulted in successful clinical results after 1 year. [PERSON] et al. [44] in 2020 also reintroduced polylactic acid (PLA) matrix barrier and evaluated the feasibility of the surgical approach. The authors recorded the change from grade II truncation to grade I, or complete resolution of the fraction involvement in 8 from 11 sites included, after a 12-month observational period [44]. In light of using periodontal regeneration in immunocompromised and systemic disorder patients, the progression of diabetes mellitus and the response to periodontal treatment such as GTR are affected by the patient's susceptibility to periodontal disease and delayed wound healing. Various mechanisms were involved for delayed wound healing, such as microvascular complications, impaired cell function, decreased tissue oxygenation, increased collagenase production, the deregulation of cytokines at the wound site and the decreased migration of periodontal ligament cells, which may affect the regeneration [45,46]. Therefore, patients with diabetes need close monitoring and frequent follow-ups of the GTR site to attain long-term success. Guided tissue regenerative therapy is more effective in improving the periodontal treatment outcome compared to the open flap debridement procedure, including improved clinical attachment gain, the reduction in probing depth, and the gain in hard tissue. However, there are a few limitations in this systematic review as a result; it is difficult to draw general conclusions about the clinical benefit of resorbable GTR membrane. Although there is evidence that GTR therapy can lead to significant regeneration over conventional flap surgery, the factors affecting outcomes are unclear, and these might include study conduct issues such as bias.