Dental caries shallow-layer microbe harvest and data display method shows taxa pre-harvest spatial positions, absolute and relative abundance and diversity related to lesion pulpal depth.

Background: Molecular identification of dental caries microbes is advancing rapidly, yet sampling methods remain outdated and imprecise. Objective: To refine microbe sample harvesting and preserve taxa pre-harvest spatial positions relative to lesion pulpal depth. Methods: Refinements included a sterile zone surrounding the dissection site and emphasize asepsis, surgical microscope magnification and lighting, and micro-surgical techniques. Retention of taxa pre-harvest spatial positions relative to lesion pulpal depth used shallow-layered dissection (mean 6 mg/layer, SD 2.65 mg), where each layer became a separate sample for molecular identification before sequential reassembly in a layered lesion diagram. To evaluate the method's robustness, 14 lesions varying in severity and type from private dental practices were dissected using the method (7 pit and fissure and 7 facial lesions; 4 untreated, 3 treated). Results: Pre-harvest taxa detail, not possible previously, showed taxa location, abundance and diversity relative to lesion pulpal depth, as well as absolute abundance per milligram and taxa transitions and fluctuations from superficial through the deepest dissected layers. The method provides these data regardless of lesion type, stage, or complexity, whether untreated or treated. Conclusions: This method provides new details and perspectives on dental caries taxa that could help develop diagnostic instruments and treatments to halt dental caries progression.