Morphological Identification and Colony Count of Bacteria in Residual Root Pulp for Supporting Human DNA Examination

Necrotic root canal residual pulp provides a confined environment with limited oxygen availability that favors bacterial colonization. The presence of bacteria, particularly anaerobic and Gram-negative species, has the potential to reduce the quality of human DNA through enzymatic degradation or co-extraction of bacterial DNA during the isolation process. Therefore, information regarding bacterial characteristics within residual pulp tissue may serve as important supporting data in human DNA examination. This study aimed to identify bacterial morphology and quantify bacterial colony numbers in root canal residual pulp as supplementary information for human DNA analysis. This analytical observational study employed a cross-sectional design involving sixteen root remnant samples. Bacterial morphology was examined using Gram staining, while colony enumeration was conducted using the spread plate method on Mueller Hinton agar. Colony forming units per milliliter were calculated using a colony counter, followed by descriptive analysis. All samples demonstrated the presence of Gram-positive bacteria, whereas Gram negative bacteria were detected only in several samples. Rod-shaped bacteria were predominant, alongside cocci and mixed bacterial forms. The mean colony count was 108.94 CFU, indicating a consistent and substantial degree of bacterial colonization within necrotic root canal residual pulp. These findings suggest that necrotic residual pulp predominantly harbors Gram positive rod-shaped bacteria, and the bacterial load observed may have implications for the integrity and reliability of human DNA examination.