Histopathology of root surface caries

Prevalence of Arrested Caries in Three Areas of South India with Different Groundwater Fluoride Levels: An Epidemiological Study

Background

Dental caries, though a progressive disease, if intervened early may become arrested, provided there is a change in the oral environment. One such factor which may lead to caries arrest is prolonged exposure to naturally available groundwater fluoride.

Aim

The aim of the study is to know the prevalence of arrested caries in three geographical areas with different levels of fluoride in groundwater and to attribute if there is any correlation between the natural high fluoride levels in groundwater and the prevalence of arrested caries.

Design

A cross-sectional study is conducted on schoolchildren residing in three geographical areas of south India with high, moderate, and low groundwater fluoride levels. A total of 5,982 children, from all the three regions between the age-groups 5-9 years, are examined and 1,514 children with caries are included in the study. The teeth and surfaces with active and arrested caries are identified and recorded in a structured pro forma. All the data obtained was tabulated and subjected to statistical analysis.

Results

The prevalence of arrested carious lesions is found to be significantly higher in areas with high groundwater fluoride level when compared to the other two areas.

Conclusion

It can be concluded that the progression of caries in children residing in areas with high groundwater fluoride level is slow and gets arrested early in the presence of a high amount of fluoride.

How to cite this article

Mudusu SP, Jampanapally SR, Konda S, et al. Prevalence of Arrested Caries in Three Areas of South India with Different Groundwater Fluoride Levels: An Epidemiological Study. Int J Clin Pediatr Dent 2022;15(S-2):S186-S190.

Root caries: a periodontal perspective

BACKGROUND AND OBJECTIVE

A prevailing dental problem in the periodontal patient is root caries. Specifically, periodontal involvement often results in root surfaces becoming exposed and at risk for this condition. Periodontal therapy often leads to increased gingival recession as well, and the associated increased root caries risk may compromise the long-term success and survival of periodontally treated teeth.This narrative review will address the topic of root caries in the periodontal patient, focusing on unmet research needs.

MATERIAL AND METHODS

The Medline database was searched to identify items dealing with root caries, in terms of clinical features, diagnosis, pathogenic mechanisms and histopathology, as well as epidemiology, focusing then on the relationship between root caries and periodontal disorders.

RESULTS

Although there is extensive literature on root caries, consensus is lacking regarding certain aspects, such as diagnostic criteria, prevalence within populations and indisputable risk factors. Advancing age could be an aggravating factor in susceptibility to root caries for the periodontal patient; however, definitive evidence in this regard is still missing. Similarly, full awareness of the increased risk of root caries in patients with periodontal disease or long-term periodontal treatment appears to be still lacking.

CONCLUSION

Research regarding root caries in age-specific (elderly) periodontal patients is needed. Improved oral hygiene practices, locally applied preventive measures, good dietary habits and regular dental check-ups are crucial approaches to prevent both periodontal disease progression and root caries. Periodontal patients with root exposure should follow a strict root caries prevention protocol, as an integral component of their periodontal maintenance therapy.

A Histological Study of Peripheral Dental Caries of Equine Cheek Teeth

Peripheral caries of equine cheek teeth is a poorly described disorder and, in particular, little is known of its histopathology. Histological examinations of decalcified sections of 21 equine peripheral caries-affected cheek teeth showed two different patterns of cemental lesions; including progressive enlargement of focal, flask-like lesions leading to breakdown of the adjacent cementum, and secondly; a more generalized flaking-off of thin layers of under-run, surface cementum. A thick layer of plaque and food material usually lay on the surface of affected cementum and also within cemental defects. Gram-stained sections showed large numbers of bacteria within the lacunae and canaliculi of affected peripheral cementum and within associated plaque. Pioneer bacteria were also seen within dentinal tubules of adjacent, normal-appearing dentin. Subgingival extension of peripheral caries lesions with localized periodontal destruction was rare. Grading of peripheral caries lesions by gross examination was found to underestimate the severity of the disorder as compared to histological grading.

Remineralization of human natural caries and artificial caries-like lesions with an experimental whisker-reinforced ART composite

This paper compares the remineralization of human natural caries and artificial caries-like dentin lesions treated with a novel whisker-reinforced experimental composite resin (ART composite) with a resin-modified glass ionomer cement (RM-GIC) as control. Ten molars with moderate natural dentin caries were prepared (N). Artificial caries-like dentin lesions were prepared in occlusal dentin of 10 caries-free molars and demineralized at pH 4.3 for 48 h (A). The cavities were restored with ART composite or RM-GIC. All restored teeth were sliced into 120 μm sections. Transverse microradiography combined with digital image analysis was performed to analyze the change in mineral density at the same position in the specimens before and after 4 and 8 weeks remineralization/demineralization treatment. The mean percent remineralization ± standard deviation after 4 and 8 weeks are: N with ART composite, 27 ± 9 and 46 ± 14, respectively; N with RM-GIC, 18 ± 6 and 36 ± 11, respectively; A with ART composite, 48 ± 9 and 66 ± 11, respectively; A with RM-GIC, 50 ± 13 and 62 ± 11, respectively. There was a significant difference between the ART composite and RM-GIC for the remineralization of natural caries (P<0.05). For both restoratives there were significant differences between the remineralization of natural and artificial caries (P<0.001). The ART composite and RM-GIC remineralized natural and artificial caries differently, most likely due to differences in the microstructure and composition of the caries dentin.

Comparative study of in vitro caries-like lesions and natural caries lesions at crown margins

PURPOSE

Secondary caries at crown margins and the influence of preparation techniques are major clinical problems. It was therefore the aim of this study to compare natural caries lesions at crown margins with experimental caries lesions.

MATERIALS AND METHODS

Five extracted caries-free human molars were restored with gold cast crowns and afterwards covered with wax leaving a 3 x 3 mm window at the crown margin. These teeth were then incubated in acidified gel (pH 4.7) for 50 days. After incubation these teeth and five other crowned extracted teeth exhibiting natural caries lesions were embedded in Technovit 9100. Serial sections with a thickness of 80 microm were cut through the lesions and investigated with polarized light microscopy (PLM) and scanning electron microscopy (SEM) combined with energy dispersive X-ray (EDX) analysis for quantitative element analysis of Ca, P, and C. The results of the quantitative element analysis were statistically evaluated using the nonparametric ANOVA test for repeated measurements.

RESULTS

PLM of the experimental lesions showed homogeneous lesions with no transparent zone, or dead tracts. The natural caries lesions exhibited a demineralized zone, translucent zone, and dead tracts. Quantitative element analysis showed a statistically significant difference (p < 0.01) of Ca, P, and C between sound dentin and demineralized dentin in natural and experimental caries lesions.

CONCLUSION

The experimental model reproduces the demineralization pattern of secondary caries but does not simulate the vital dentin reactions of peritubular and intratubular mineralization.

The efficacy of techniques for the disinfection of artificial sub-surface dentinal caries lesions and their effect on demineralization and remineralization in vitro

OBJECTIVES

The efficacy of three techniques for the disinfection of artificial sub-surface root caries lesions and their response to subsequent episodes of de- and remineralization was investigated quantitatively in vitro.

METHODS

Sub-surface dentinal lesions (n=20), cut into four experimental blocks and deliberately contaminated with Streptococcus mutans, were subject to either steam autoclaving (121 degrees C, 5min), gamma irradiation (4100Gy), immersion in 0.1% (w/v) thymol-distilled water solution (24h) or reserved as a control. Next, the lesions were incubated aerobically in sterile nutrient broth for 24h at 37 degrees C and resultant cultures plated onto blood agar and neutralisation agar. Ten blocks from each experimental group were then immersed in an acidic buffer solution or exposed to artificial saliva for 5 days. Baseline changes in the mineral content and distribution of the lesions were assessed by transverse microradiography (TMR).

RESULTS

Micro-organisms were recovered from each control block and one block treated by gamma irradiation. Steam autoclaving and immersion in a thymol solution significantly decreased (p<0.05) the amount of mineral lost from the body of lesions subject to a further acid challenge. Mineral ion uptake by lesions exposed to artificial saliva was significantly increased (p<0.05) through disinfection by steam autoclaving.

CONCLUSIONS

Gamma irradiation proved the most acceptable method for the disinfection of sub-surface root dentine lesions having the least adverse effect on demineralization and remineralization.

Development of an in situ root caries model. A. In vitro investigations

OBJECTIVES

The paper describes preliminary in vitro investigations, the objectives of which were to examine the influence of certain experimental parameters on artificial carious lesion formation in root hard tissues, and their remineralisation. These experiments formed part of a wider study that aimed to develop an in situ model of root caries, based on the existing coronal caries model used in Liverpool. The present studies examined the effects (a) of the anatomical origin of the dentine, the presence or absence of cementum, the exposure time and the type of demineralising system, on lesion development, and (b) of baseline lesion size on the extent and location of mineral re-precipitation.

METHODS

Mineral content parameters in plano-parallel sections taken from dentine lesions were determined by computer-controlled transverse microradiography.

RESULTS

The importance of the anatomical origin of the dentine on lesion formation was investigated by comparing in vitro lesion formation in premolar and molar dentine, and in dentine from apical, middle and coronal thirds of the root: no difference was observed between these sites. Lesions formed more rapidly in acid buffer solutions than in acid gel systems, and were more reliably produced when cementum was removed. The effect of baseline lesion size on subsequent in vitro remineralisation demonstrated that a small baseline mineral content was associated with a larger percentage mineral gain. The location of mineral deposition throughout the lesion was also influenced by baseline mineral content parameters.

CONCLUSIONS

The results form a basis for the further development of an in situ dentinal caries model, providing data to suggest that manipulation of parameters involved in the preparation of artificial carious lesions has a significant effect on the behaviour of the lesion, particularly the phenomenon of remineralisation. Further work is needed to investigate the behaviour of the model in situ.

Explorer probing of root caries lesions: an in vitro study

Probing with a dental explorer is the preferred method of root caries diagnoses. However, studies suggest that use of a dental explorer in coronal caries detection may damage tooth structure. This pilot study investigated the effect of probing on remineralization of root surface lesions in vitro. Root-surface lesions were created on 10 extracted teeth by exposing them to a demineralizing solution for 21 days. One side of each lesion was then randomly selected and probed with an explorer, while the other side was not probed. The teeth then were placed in a remineralizing solution containing 10 parts per million (ppm) fluoride for 21 days. Of the 9 teeth with usable sections, all showed frank evidence of defects on the probed halves. Sites of remineralization were seen in the non-probed halves and adjacent to the probed defects, but not within or at the base of these defects. These results suggest that probing of root surfaces may create defects that do not fully remineralize.

Non-invasive management of superficial root caries lesions in disabled and infirm patients

In disabled and infirm patients with limited, if any, capacity for independent oral self-care, it is difficult to control progression of root caries lesions.

OBJECTIVE

To evaluate the effect of non-restorative cariostatic treatment on progression of active superficial root caries lesions (n = 56).

DESIGN

Pilot study.

SETTING

Department of Cariology, Institute of Odontology, Karolinska Institutet, Huddinge.

SUBJECTS

15 physically-dependent patients.

INTERVENTION

The patients were allotted to one of the following groups. Group 1, professional tooth cleaning and application of tap water flavoured with eucalyptus oil; Group 2, professional tooth cleaning and application of Cervitec, (1% chlorhexidine in thymol-containing varnish), Group 3, professional tooth cleaning and application of Cervitec and Fluor Protector (varnish containing 0.1% fluoride). Every three months for 18 months, each subject received the treatment twice within a 10-day interval.

MEASUREMENTS

The status of the 56 root caries lesions was evaluated every six months using a root caries index based on visual and tactile criteria. The examiners were blind to which treatment group the patients belonged.

RESULTS

In most subjects (14 out of 15), progression of root caries lesions was arrested. No statistically significant differences could be demonstrated between the three treatment groups. However, regardless of treatment regimen, there was a statistically significant difference between the greater number of subjects exhibiting no progression of root caries lesions and those with lesion progression, at 6 (p = 0.022), 12 (p = 0.006) and 18 months (p < 0.001).

CONCLUSION

This pilot study suggests that in disabled and infirm patients regular professional tooth cleaning with a fluoride containing paste, with or without supplementary varnishing with chlorhexidine-thymol and/or fluoride can prevent further progression of existing superficial root caries lesions.

Dental caries in chronically disabled elders

Dental caries is the major cause of tooth loss in elderly individuals with physical and mental disabilities. The diagnosis of caries in elderly individuals is difficult due to a complicated oral environment compounded by the prevalence of physical and mental barriers to care. The restoration of tooth structure and the replacement of teeth lost due to caries result in considerable economic and biological cost to both individuals and society. Decisions to remineralize, restore, or extract teeth depend largely upon the extent of the structural damage caused by the infection. Teeth with small lesions can be remineralized with fluorides, whereas teeth with large lesions may be restored or extracted. Caries risk assessment based on the history of previous infection, salivary parameters, and ingestion of sugar can be used as a basis for placing a patient on a caries-preventive regimen. This paper discusses the pathophysiology of caries to explain the appropriate diagnosis, prevention, and treatment of dental caries in elderly individuals with chronic disabilities.

How severe is the threat of caries to old teeth?

Caries is a bacterial infection caused by a complex interaction of biologic and behavioral factors. It is believed that caries is a major threat to teeth in old age, yet little information is available on the incidence and progress of carious lesions in elderly teeth. All too often caries is diagnosed after a visual and tactile examination of tooth structure without thought for the other factors essential to the initiation and support of an active lesion. Prospective studies have been conducted recently in Vancouver to quantify associations between the incidence of caries and many of the behavioral, bacteriologic, and physiologic factors potentially influencing oral health in old age. The results indicate that improvements in hygiene may hold the most promise for controlling this infection in an elderly population.