Whilst there is evidence that GTR can demonstrate a significant improvement over conventional open flap surgery, the factors affecting outcomes are unclear from the literature and these might include study conduct issues such as bias. Therefore, patients and health professionals need to consider the predictability of the technique compared with other methods of treatment before making final decisions on use." Enamel matrix derivative
Enamel matrix derivative (EMD) is favoured by some practitioners despite its high cost:  "One year after its application, EMD significantly improved probing attachment levels (1.1 mm) and probing pocket depth reduction (0.9 mm) when compared to a placebo or control, however, the high degree of heterogeneity observed among trials suggests that results have to be interpreted with great caution. In addition, a sensitivity analysis indicated that the overall treatment effect might be overestimated. The actual clinical advantages of using EMD are unknown. With the exception of significantly more postoperative complications in the GTR group, there was no evidence of clinically important differences between GTR and EMD. Bone substitutes may be associated with less gingival recession than EMD. "However, studies have shown that regardless of the conventional periodontal treatments, 20-30% of chronic periodontitis patients do not respond favorably to their treatment. There are many factors which account for these including: ineffective removal of calculus, defective restorations, impaired immune response as a result of a systemic condition, poor plaque control, smoking, etc. Adjunctive systemic antibiotic treatment
Systemic antibiotics such as amoxicillin or metronidazole are sometimes used in addition to debridement based treatments.
The anterior dentition occasionally have recession and maxillary anterior and palatal surfaces are more adversely affected. Pathophysiology
Chronic periodontitis is initiated by Gram-negative tooth-associated microbial biofilms that elicit a host response, which results in bone and soft tissue destruction. In response to endotoxin derived from periodontal pathogens, several osteoclast-related mediators target the destruction of alveolar bone and supporting connective tissue such as the periodontal ligament. Major drivers of this aggressive tissue destruction are matrix metalloproteinases (MMPs), cathepsins, and other osteoclast-derived enzymes. Plaque hypothesis
At least two mechanisms of the microbiology of periodontitis have been described: the specific plaque hypothesis and the non-specific plaque hypothesis. Consensus is that neither view is entirely correct, but via a middle path, that damage is due to a shift in the relative populations of more and less dangerous bacteria in the plaque. This is called the ecological plaque hypothesis. The disease is associated with a variable microbial pattern.Anaerobic species of bacteria Porphyromonas gingivalis, Bacteroides forsythus, Treponema denticola, Prevotella intermedia, Fusobacterium nucleatum, Eubacterium sp. have all been implicated in chronic periodontitis.Microaerophile bacteria Actinomyces actinomycetemcomitans, Campylobacter rectus, and Eikenella corrodens also may play a role in chronic periodontitis. Signs and symptoms
In the early stages, chronic periodontitis has few symptoms and in many individuals the disease has progressed significantly before they seek treatment. Symptoms may include the following:

Redness or bleeding of gums while brushing teeth, using dental floss or biting into hard food (e.g.