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Pathology is the science of how a tissue changes during the process of the disease. The pathology is of important knowledge for understanding subsequent treatment concepts of a disease. In the cariology field, pathological features of caries are often presented using tooth sections, whereby the sequence and spread can be monitored. It is optimal to describe such changes using thin undecalcified tooth sections as an overview can be given of both enamel demineralization and pulp-dentine reactions. Also, an optimal understanding is achieved if the clinical status of carious lesion activity is known. Different studies using human teeth have shown the principle changes in progressive stages of carious lesions; the growth of the enamel lesion reflects the growth condition of the cariogenic biofilm. Surprisingly, the pulp (the odontoblast) is aware of the cariogenic stimuli even before mineral alteration has taken place within the dentine. The microorganisms mainly invade the dentine during enamel cavitation. In this chapter, the current improvement of knowledge on advanced carious lesions has been assessed in detail both histologically and radiographically. From a radiographic point of view, well-defined deep and extremely deep carious lesions and their difference are presented. Recent advances in artificial intelligence (AI) in medicine have raised the possibility of increasing the accuracy and speed of histopathological examination techniques. However, the literature involving AI-based histopathological features of hard and soft dentinal tissue pathologic changes is still scarce., (© 2023 S. Karger AG, Basel.)

Unlabelled: This paper discusses the excavation of deep caries lesions, focusing on indirect pulp-capping and the stepwise excavation approach. The concept of a modified and less invasive stepwise excavation is presented, based on considerations of caries pathology. The aim of the first excavation is primarily to make a change within the cariogenic environment, and not to remove carious dentine close to the pulp because this risks an iatrogenic pulp exposure. Microbiological and clinical studies have shown that the number of bacteria decrease during stepwise excavation procedures, and that lesions clinically arrest. The active, soft-yellowish, demineralized dentine turns into a darker, harder and drier demineralized dentine, resembling a slowly progressing lesion, where the carious dentine is easier to remove at the final visit. The final excavation has two aims: (i) to verify that arrestation has taken place, ie a clinical control of the tooth reactions and (ii) to remove the slowly progressing but still slightly infected discoloured demineralized dentine, before carrying out the permanent and final restoration., Clinical Relevance: Knowledge of guidelines for treatment of deep dentine caries may reduce the risk of pulpal exposure.

The infectious disease denial caries results in lesions that may affect enamel, dentin, pulp, and cementum. If a caries lesion has progressed to the stage at which it requires restorative intervention, it is important that the clinician understand the tissue changes in the dentin that are likely to have taken place during lesion development. Until the present, no major distinction between the restorative treatment of active (rapidly progressing) and arrested (slowly progressing) lesions has been made, despite the fact that the two conditions exhibit major differences in tissue changes in the pulp-dentin complex. Intratubular changes and tertiary dentin formation will affect the outcome of the restorative treatment. In unaffected dentin and in rapidly progressing lesions, permeable tubules persist, and when the preparation of carious teeth results in the opening of unaffected dentin, greater care must be taken in all phases of the restorative procedures than if the dentin is impermeable. An active, deep lesion can be changed to an arrested lesion by a two-step excavation approach. Optimal assessment of the prevailing clinical conclusions can only be made on the basis of thorough knowledge of the biology of the pulp-dentin organ. (Quintessence Int 2001.'32. 717-736) [ABSTRACT FROM AUTHOR]

The caries process in dentin involves the degradation of both mineral and organic matrix. The demineralization has been demonstrated to be caused by bacterial acids. However, the collagen degradation is considered to be initiated by endogenous proteolytic enzymes, mainly collagenolytic matrix metalloproteinases (MMPs). This paper aims to relate salivary MMP-8 (or salivary collagenase-2) and tissue inhibitor of MMP (TIMP-1) levels to manifest caries in a large number of subjects. A random sample of 451 adults (aged 18-87 years) living in the south of Sweden was included in this study. Standard clinical examinations were performed, and stimulated saliva was collected and analyzed for concentrations of MMP-8, TIMP-1 and total protein, using an immunofluorometric assay, an enzyme-linked immunosorbent assay and the Bradford assay, respectively. Salivary numbers of mutans streptococci and lactobacilli were determined using a chair-side kit. Subjects with manifest caries lesions presented with elevated levels of MMP-8 (p < 0.001) as well as total protein, MMP-8/TIMP-1 ratio, bleeding on probing and plaque index (p = 0.05) compared with subjects without manifest caries. Multiple linear regression analysis with caries as the dependent variable revealed MMP-8 as the only significant explanatory variable (p < 0.001). TIMP-1 was not significant in any case. Using MMP-8 as the dependent variable revealed total protein concentration, caries lesions (p ≤ 0.001) and salivary secretion rate (p = 0.05) as explanatory variables. In conclusion, our data reveal that subjects with manifest caries lesions have elevated levels of salivary MMP-8 relative to subjects with no caries lesions. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The understanding of the caries process and its effect on the pulp is presented in the context that caries does develop in various rates of progression. Early in the caries process, the pulp reflects changes within lesion activity Thus, the early pulp response is reversible. Later, the rate of caries progression is reflected by the quality of the tertiary dentin. Slowly progressing lesions create tertiary dentin resembling normal tubular dentin. Rapidly progressing lesions lead to the production of atubular dentin or complete absence of tertiary dentin, as well as pulp necrosis and apical pathology Finally, the nature of the untreated deep carious lesion is an ecosystem that might undergo significant changes. The untreated lesion is temporarily converted from an active and closed lesion environment into one that is open and slowly progressing. The analysis of untreated carious lesions has transformed the treatment philosophy of deep carious lesions. [ABSTRACT FROM AUTHOR]

This study reports results from a practice-based study in which deep carious lesions were treated by general dental practitioners using stepwise excavation. The material comprised 94 teeth with deep carious lesions which the clinicians considered would result in pulp perforation if treated by a single and terminal excavation. At the first visit excavation of the peripheral dentine was completed. The outermost part of the central and necrotic dentine was gently removed with a sharp excavator. Standardized assessments of the dentine colour and consistency were made before application of a calcium hydroxide-containing base material and temporary filling. The final excavation was completed after a treatment interval ranging from 2 to 19 months, with a median of 6 months. Reassessments of the dentine colour and consistency were made before complete removal of demineralized dentine. The central dentine was significantly browner and less softened after the sealing period. After removal of the dark-brownish dentine during the final excavation, the colour and consistency of the exposed central dentine was found to resemble that of the completely excavated peripheral dentine. Only five cases resulted in pulp perforation during the final excavation. The high success rate of teeth surviving the final treatment without pulp exposure after 1 year of observation shows that it was possible for dentists in general practice to administer and manage the treatment of deep carious lesions, a process which may prolong tooth survival compared with conventional endodontic techniques. [ABSTRACT FROM AUTHOR]

The present study examines the correlation between caries lesions in enamel and the corresponding dentin reactions in proximal tooth surfaces with lesions ranging from enamel lesions to cavitations without dentin exposure. Using quantitative inhibition technique, the highest degree of tissue porosity, irrespective of lesion activity, was always noted along a Central-Traverse (CT), which followed the direction of the rods from the deepest point of penetration to the surface. The conical shape of approximal enamel lesions can thus be seen as the result of systematic variations in porosity along the rods determined by the specific interproximal environment. The initial dentin reaction, related to the enamel lesion approaching the enamel-dentin junction (EDJ), was seen as a local dentin translucency where the CT crossed the EDJ. Results from histomorphometric analyses revealed that, when the enamel lesions reached the EDJ, brownish discoloration in the dentin never exceeded the histologic contact area between the enamel lesion and the EDJ. In relation to the less advanced parts of the individual enamel lesion, the dentin responded with formation of translucent dentin. These reactions did not occur beyond an area determined by lines in the direction of the rods from the peripheral part of the enamel lesion towards the EDJ. The results did not support the view that dentin caries spreads along the enamel-dentin junction. The peripheral dentin translucency is therefore generated by stimuli transmitted along the rods of the less advanced parts of the enamel lesions.

Abstract: Various treatment concepts have been suggested to solve the deep carious lesion dilemma. Recent systematic reviews are presented. Their conclusions are based on very few studies, and the main message is that optimal randomized clinical studies are lacking. Observational studies on indirect pulp treatment and stepwise excavation demonstrate that these treatments avoid pulp exposures, but it cannot be said which approach is best. A less invasive modified stepwise excavation approach is described, focusing on changing an active lesion into an arrested lesion even without performing an excavation close to the pulp. In Denmark and Sweden a randomized clinical multi-center trial is currently taking place, the Caries and Pulp (CAP) trial. This trial is investigating the effects of stepwise excavation over 2 visits versus 1 complete excavation of deep caries in permanent teeth. Guidelines for treatment are presented. [Copyright &y& Elsevier]