Changes in the Cultivable Flora in Deep Carious Lesions following a Stepwise Excavation Procedure

Abstract

This study examined the cultivable microflora before and after stepwise excavation procedures in deep carious lesions in 9 permanent teeth, categorized according to degrees of proximal surface destruction. The final excavation was performed 4–6 months after the initial treatment, which included peripheral dentine excavation and removal of the central cariogenic biomass and the superficial necrotic dentine. Dentine colour and consistency were assessed by means of standardized scales before the application of a Ca(OH)₂ compound and temporary sealing. Reassessments were performed before and after the final excavation. Microbiological samples of the central demineralized dentine were obtained with a sterile bur before and after the first excavation, as well as before and after the final excavation. After anaerobic cultivation on enriched non–selective tryptic soy agar, 30 colonies from a representative area were identified by standardized biochemical and physiological tests. Before temporary restoration, a yellowish and light brown demineralized soft dentine was typically observed, and gram–positive rods accounted for 70% and lactobacilli for 50% of the total colony–forming units. Lactobacillus casei subsp. rhamnosus and Actinomyces naeslundii dominated the lactobacilli and the other gram–positive rods, respectively. Gram–negative rods were the next most frequent isolates, followed by streptococci, each group accounting for about 20% of the colony–forming units in positive samples. Before the final excavation, which did not cause exposure of the pulp in any of the cases, the retained demineralized dentine had changed into a darker and harder tissue, and the total colony–forming units, as well as the frequency and proportions of lactobacilli were substantially reduced. Gram–negative rods also declined, and the flora was dominated by A. naeslundii and various streptococci. In conclusion, the cultivable flora detected following the treatment interval had declined substantially, and the distribution of bacterial species did not represent a typical cariogenic microbiota of deep lesions, confirming the clinical findings of arrested caries progression.

Efficacy of chemomechanical caries removal in reducing cariogenic microbiota: a randomized clinical trial

“…1,4,6,12,21 In pediatric dentistry, chemomechanical methods (Carisolv ™ and Papacárie ® ) and ART aim to remove only softened and infected dentine, avoiding over-preparation of the cavity, eliminating pain and discomfort, and reducing both the need for anesthesia and the level of dental anxiety. Satisfactory results with chemomechanical methods have been observed in clinical studies, in regard to preserving tooth structure and promoting patient acceptability.…”

“…1,2,3 Based on the minimal invasive dentistry concept, more conservative approaches have been recommended, 4,5 such as partial caries removal, 6 atraumatic restorative treatment 7 and chemomechanical methods, 8,9 instead of conventional caries removal by drilling and manual excavation.…”

Acciones Terapéuticas Actuales en Caries Profunda. Revisión

“…The lack of specificity of physical 18 and chemical 21,22 methods to identify the boundary of carious tissue to remove, the defense mechanisms of the dentin pulp complex, as well as the arrest of the progression of sealed carious lesions 24,25 allow us to treat deep carious lesions Different authors agree on complete caries removal from lateral walls. This is how adhesives act most efficiently, ensuring good sealing to prevent the penetration of nutrients to the residual bacteria, thus arresting the lesion 24,25,35 .…”

“…This is how adhesives act most efficiently, ensuring good sealing to prevent the penetration of nutrients to the residual bacteria, thus arresting the lesion 24,25,35 . There are differences regarding: amount of dentin infected left on the pulp or axial wall, protector used, waiting time before reopening and need to reopen.…”

“…When we consider the limitations of physical and chemical methods, and based on multiple microbiological studies that have shown that sealed carious lesions present fewer bacteria, inactivation and progression arrest, there is a change in the idea of how dentin caries should be treated 24,25 .…”