The position and extent of acid in the carious process

MacGregor, Alexander B.

doi:10.1016/0003-9969(61)90084-x

Cited by 26 publications

(10 citation statements)

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“…Further, using finer antimony electrodes, a positive correlation between late stages of caries and the fall in pH value on the surface of the tooth was concluded [29]. Methyl red was used later and showed pH of below 5 in carious dentine [10]. The use of an antimony pH electrode was reported as a useful tool in plaque pH studies [27].…”

Section: Discussionmentioning

confidence: 99%

“…The profiles of pH and organic acids within carious dentine have been of interest to researchers in the field, since Stephan's description of caries as a pH-mediated disease [8, 9]. Macgregor studied the presence of acid in dentine and enamel caries using methyl red to confirm low pH values in dentine lesions [10]. While acid and base production by bacteria and their pH lowering potential and tolerance has been widely studied in vitro [5, 11–15], the pH and organic acid composition of dentinal caries was not examined, until Hojo et al demonstrated ex vivo the organic acid profile and pH of carious lesions of dentine [16].…”

Section: Introductionmentioning

confidence: 99%

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pH gradient and distribution of streptococci, lactobacilli, prevotellae, and fusobacteria in carious dentine

et al. 2013

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Objectives Caries process comprises acidogenic and aciduric bacteria that are responsible for lowering the pH and subsequent destruction of hydroxyapatite matrix in enamel and dentine. The aim of this study was to identify the correlation between the pH gradient of a carious lesion and proportion and distribution of four bacterial genera; lactobacilli, streptococci, prevotellae, and fusobacteria with regard to total load of bacteria. Materials and methods A total of 25 teeth with extensive dentinal caries were sampled in sequential layers. Using quantitative real-time PCR of 16S rRNA gene, we quantified the total load of bacteria as well as the proportion of the abovementioned genera following pH measurement of each sample with a fine microelectrode. Results We demonstrated the presence of a pH gradient across the lesion with a strong association between the quantity of lactobacilli and the lowest pH range (pH 4.5–5.0; p = 0.003). Streptococci had a tendency to occupy the most superficial aspect of the carious lesion but showed no correlation to any pH value. Prevotellae showed clear preference for the pH range 5.5–6.0 (p = 0.042). The total representation of these four genera did not reach more than one quarter of the total bacterial load in most carious samples. Conclusion We revealed differential colonization behavior of bacteria with respect to pH gradient and a lower than expected abundance of lactobacilli and streptococci in established carious lesions. The data indicate the numerical importance of relatively unexplored taxa within the lesion of dentinal caries. Clinical relevance The gradient nature of pH in the lesion as well as colonization difference of examined bacterial taxa with reference to pH provides a new insight in regard to conservative caries management.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

pH gradient and distribution of streptococci, lactobacilli, prevotellae, and fusobacteria in carious dentine

et al. 2013

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“…Two validation methods were chosen to assess activity of the lesion: use of methyl red dye which changes colour at pH about 5.5 [Holtzclaw et al, 1991] and a polarized light examination. The dye method was described many years ago [MacGregor, 1961] and we initially doubted that this simple test would be useful. A pilot study carried out on 33 extracted teeth, however, reassured us that use of methyl red dye was a good validation of lesion activity.…”

Section: The Validation Methodsmentioning

confidence: 99%

Detection, Diagnosing, Monitoring and Logical Treatment of Occlusal Caries in Relation to Lesion Activity and Severity: An in vivo Examination with Histological Validation

et al. 1998

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The aims of the present study were to investigate the ability of 3 experienced clinicians to detect occlusal carious lesions, assess their depth, diagnose their activity and define a logical management for each lesion. The material consisted of 35 third molars scheduled for extraction or surgical removal making it possible to validate the accuracy of the clinical recordings histologically. Examinations were carried out at baseline and after 4 months in order to monitor lesion progression. At the first visit a radiograph was taken; the number of filled surfaces was counted and the oral hygiene assessed generally and by disclosing occlusal plaque of the tooth under examination. After cleaning the occlusal surface caries was recorded in a selected investigation site using a visual ranked caries scoring system, as well as an electrical conductance recording (ECM). Apart from counting fillings and taking new radiographs the same procedure was performed at the second visit, which then was followed by extraction of the tooth. After sectioning the tooth lesion depth was recorded, and lesion activity, based on acid production, was assessed using methyl red dye. Lesion activity was also judged by means of polarized light microscopic examinations of the sections. Results showed strong relationships between the visual, ECM and radiographic assessments and both lesion depth and lesion activity. In contrast, all other parameters were poorly related to lesion activity. Changes in visual assessments and in conductance readings from first to second examination were poorly associated with lesion activity. In conclusion, clinicians are able to detect lesions, predict activity and severity and define a logical management of occlusal caries on the basis of a single examination.

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“…For the assessment of caries activity, a methyl red solution at a concentration of 0.1% was applied on each section [MacGregor, 1961;Ekstrand et al, 1998b;Braga et al, 2010aBraga et al, , 2010b. This indicator is capable of indicating a defined color change at different pH values (approx.…”

Section: Histological Preparation and Examinationmentioning

confidence: 99%

Diagnostic Accuracy of a Bioluminescence System for the Assessment of Caries Activity on Occlusal Surfaces

et al. 2018

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Objective: Assessment of caries lesion activity is usually performed using visual-tactile criteria. A new approach is to use a system consisting of a photoprotein, which is specific for free calcium ions, along with an integrated camera that visualizes the elevated calcium ions on the lesion as a light signal (bioluminescence). This study aimed to evaluate the reproducibility and diagnostic accuracy of a newly developed bioluminescence system to assess caries lesion activity on occlusal surfaces in vitro. Materials and Methods: Ninety-four extracted permanent teeth with sound surfaces and both active and inactive caries lesions were included. The extent and activity of the investigation sites were classified visually according to the International Caries Detection and Assessment System. Digital images of the teeth were produced by the bioluminescence system and the images were analyzed for the presence of caries activity (the bioluminescent areas at the investigation sites). The images were reanalyzed after 4 weeks. Teeth were hemisected and methyl red dye was applied on the sections to validate lesion activity histologically. Results: Agreement between the bioluminescence readings was shown by κ values of 0.802–0.917. A significant positive correlation (p < 0.001) was found across all methods (r_s 0.618–0.811). Sensitivity and specificity for activity assessment using histology as the gold standard (cut-off: active/inactive) were, respectively, 83.6 and 85.0% for the visual assessment, and 92.5 and 90.0% for the bioluminescence method. Comparison of areas under the receiver-operating characteristic curves showed no significant difference between the visual and bioluminescence systems (p = 0.094). Conclusion: The bioluminescence system demonstrated high in vitro reproducibility and good diagnostic accuracy for activity assessment of caries lesions on occlusal surfaces which were not significantly different from the values obtained in the visual assessment.

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The position and extent of acid in the carious process

Cited by 26 publications

References 0 publications

pH gradient and distribution of streptococci, lactobacilli, prevotellae, and fusobacteria in carious dentine

pH gradient and distribution of streptococci, lactobacilli, prevotellae, and fusobacteria in carious dentine

Detection, Diagnosing, Monitoring and Logical Treatment of Occlusal Caries in Relation to Lesion Activity and Severity: An in vivo Examination with Histological Validation

Diagnostic Accuracy of a Bioluminescence System for the Assessment of Caries Activity on Occlusal Surfaces

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