Aggregatibacter actinomycetemcomitans Alkaline phosphatase Article Gingival index Plaque index Porphyromonas gingivalis Prevotella intermedia Probing pocket depth Relative attachment level Thymoquinone adult alkaline phosphatase antibacterial activity bacterial strain chronic periodontitis clinical article controlled study dental scaling drug efficacy female gel gingival index human in vitro study male nonhuman periodontal disease assessment periodontitis plaque index probing pocket depth