Dental caries and hypoplastic amelogenesis imperfecta: Clinical, structural, biochemical and molecular approaches

Technical note: Micro-computed tomography calibration using dental tissue for bone mineral research

Computed tomography (CT) and microcomputed tomography (μCT) require calibration against density phantoms scanned with specimens or during routine internal calibration for assessment of mineral concentration (MC) and density. In clinical studies involving bone, alternative calibration methods using bodily tissues and fluids ("phantomless" calibration) have been suggested. However, such tissues are seldom available in archeological and osteological research. This study investigates the potential of dental tissue as internal reference for calibration of μCT scans, facilitating the analysis of bone MC. We analyzed 70 molars from 24 extant primate species, including eight human teeth, each scanned with density phantoms for calibration. Our findings indicate that sampling specific regions of molars (lateral aspects of the mesial cusps) yields low variation in enamel and dentine MC values, averaging 1.27 g/cm3 (±0.03) for dentine and 2.25 g/cm3 (±0.03) for enamel. No significant differences were observed across molar types or among scanning procedures, including scanner model, resolution, and filters. An ad hoc test on 12 mandibles revealed low variance in MC between the conventional phantom and dental tissue calibration methods; all 36 measurements (low, medium, and high MC for each mandible) were within 0.05 g/cm3 of each other -81% were within 0.03 g/cm3 and 94% within 0.04 g/cm3. Based on these results, we propose a new "phantomless" calibration technique using these mean enamel and dentine MC values. The presented phantomless calibration method could aid in the assessment of bone pathology and enhance the scope of studies investigating bone structure and physical property variations in archeological, osteological, and laboratory-based research.

A Review on Enhancing the Life of Teeth by Toothpaste Containing Bioactive Glass Particles

Purpose of Review

Dental caries or tooth decay is one of the communal problems in the world which can affect not only the oral health but also the general health conditions. The main objective of this systematic review is to explore the efficacy of bioactive glass-based toothpastes against cariogenic bacteria.

Recent Findings

Bioactive glass particulates containing toothpaste show better remineralization potential on demineralized enamel and dentin when compared with toothpaste containing various bioactive constituents such as fluoride and potassium chloride. These constituents in conventional toothpaste can rapidly streak off due to acidic impact in the oral environment as the bioactive glass provides minerals for demineralized enamel and dentin by forming a strong hydroxyapatite (HAp) layer on its surface. Further, the therapeutic ions present in the bioglass can resist plaque formation by raising the pH of the surrounding environment or saliva and create amicable media for healthier teeth.

Summary

Toothpaste containing bioactive glass particles undoubtedly displayed the remineralizing potentiality of the dental hard tissues. Dynamics of the mineralization through different bioactive glass materials needs further investigations. In order to prevent dental cavities and improve oral health, it is important to identify and study different effective bioglass particles in toothpaste.

Probiotic Lactobacillus plantarum Ln4 Showing Antimicrobial and Antibiofilm Effect against Streptococcus mutans KCTC 5124 Causing Dental Caries

Dental caries has known as an infectious disease that is considered a serious global public health problem. Recently, report indicate that probiotics play a vital role in maintaining oral health. Therefore, this study aimed to evaluate the prevention effects of Lactobacillus plantarum Ln4 against dental infection by the pathogenic bacterium Streptococcus mutans KCTC 5124 through biofilm formation inhibition. To evaluate such prevention effects against S. mutans KCTC 5124, antimicrobial activity, auto-aggregation, co-aggregation, cell surface hydrophobicity, total exopolysaccharide (EPS) production rate, and biofilm formation were analyzed. Results showed that L. plantarum Ln4 showed higher antimicrobial activity than L. rhamnosus GG (LGG). In the group treated with L. plantarum Ln4, the co-aggregation (58.85%), cell surface hydrophobicity (16.75%), and EPS production rate (73.29%) values were lower than those of LGG and the negative control. Additionally, crystal violet staining and confocal laser scanning microscopy (CLSM) revealed that L. plantarum Ln4 effectively inhibited biofilm formation in S. mutans KCTC 5124. Therefore, L. plantarum Ln4 could be used in the industry as a probiotics to prevent and improve oral health.

Association of KLK4 rs2235091 polymorphism with susceptibility to dental caries: a systematic review and meta-analysis

Objective

To investigate the association between Kallikrein-related peptidase-4 (KLK4) rs2235091 polymorphism and susceptibility to dental caries (DC) by a method of systematic review and meta-analysis.

Methods

Four English databases were searched for studies on the correlation between KLK4 rs2235091 polymorphism and susceptibility to DC from inception to April 1, 2023. Data analysis was processed by Stata 15.0 software.

Results

Four articles were eligible, including 848 individuals with caries and 463 controls. The results of pooled analysis showed no significant differences in the five gene models (G vs. A: odds ratio (OR) = 1.14, 95% CI: 0.73-1.79, P = 0.567; GG + GA vs. AA: OR = 1.01, 95% CI: 0.77-1.32, P = 0.489; GG vs. GA + AA: OR = 0.84, 95% CI: 0.57-1.23, P = 0.368; GA vs. AA: OR = 1.06, 95% CI: 0.80-1.41, P = 0.681; GG vs. AA: OR = 1.15, 95% CI: 0.57-2.31, P = 0.690). However, subgroup analysis indicated a statistically significant difference in the dominant (GG + GA vs. AA: OR = 1.74, 95% CI: 1.02-2.96, P = 0.042) gene model in primary dentition, but no significance in allelic, recessive, homozygous and heterozygous models. Besides, in permanent dentition, no significant differences were found among the five genetic models (all P > 0.05).

Conclusion

KLK4 rs2235091 polymorphism may be associated with susceptibility to DC of pediatric primary dentition, but not with the risk of caries of permanent dentition. Genotype GG + GA may increase susceptibility to DC of pediatric primary dentition. However, considering the limited records enrolled in this review, more trials with larger sample sizes and more rigorous designs are needed to verify the conclusions of this meta-analysis in the future.

Systematic Review Registration

https://inplasy.com/, identifier INPLASY202380014.

Clear Aligners in Patients with Amelogenesis and Dentinogenesis Imperfecta

Dentinogenesis imperfecta (DI) and amelogenesis imperfecta (AI) are hereditary abnormalities of dental hard tissues. Dental abnormalities may also be accompanied by symptoms of disorders such as osteogenesis imperfecta. AI and DI have a significant burden on socializing, function, and comfort; therefore, frequent screening and accurate diagnosis is the cornerstone of managing such conditions. Both AI and DI could be treated with many strategies, including restorative, prosthetic, periodontal, surgical, and orthodontics treatment. The interdisciplinary combination of orthodontic, prosthodontic, and periodontic treatment has been proven to improve the prognosis of AI and DI. Regarding orthodontic treatment, the most difficult element of orthodontic therapy may be maintaining a high level of motivation for what might be a prolonged form of treatment spanning several years. There are many forms of orthodontic management for AI and DI, including removable appliances, functional appliances, and fixed appliances. Clear aligner therapy (CAT) contains a broad range of equipment that works in different ways, has different construction processes, and is compatible with different malocclusion procedures. The application of CAT in patients with AI and DI is favorable over the fixed applicants. However, the available evidence regarding the application of CAT in AI is weak and heterogeneous. In this review, we discussed the current evidence regarding the application of clear CAT in patients with AI and DI.

DMF Index among Amelogenesis Imperfecta Patients: Systematic Review of the Literature

Objectives

The aim of this study was to explore the literature in order to assess systematically the association between amelogenesis imperfecta (AI) and caries development and to evaluate the DMF index among AI patients. Basic Research Design. PubMed was used to explore the database Medline. The key words used were “Amelogenesis Imperfecta” [Mesh], “Dental Caries” [Mesh], “Tooth Loss” [Mesh], “DMF Index” [Mesh], and “Dental Restoration, Permanent” [Mesh]. Moreover, an ad hoc search was performed in order to make the study as exhaustive as possible.

Results

Fifty-five articles were retained. The total number of patients gathered was 499. A percentage of 68.8% of the articles dealt with cases with a relatively low dental caries process, 20.8% dealt with cases in which the dental caries process was relatively moderate, and 10.4% dealt with cases in which the dental caries process was severe. Teeth extraction due to dental caries was mentioned in 10 articles. Eleven articles, concerning 53 patients, mentioned dental fillings. Four patients did not have dental filling due to dental caries. DMF index was very low in 2 articles and low-to-high in 3 articles.

Conclusion

Low dental caries susceptibility with AI patients was noticed in this study. A possible factor could be the lack of proximal contacts and elimination of fissures through enamel loss. The lack of dental caries susceptibility was also explained by the microbacterial specificity of hypoplastic AI patients. Moreover, it was also noted that the prevalence of dental caries among AI patients depends on sociodemographic change.

Amelogenesis Imperfecta Enamel Changes, Amelogenin, and Dental Caries Susceptibility

There is great interest in identifying the subset of individuals in the population that are more susceptible to dental caries. We proposed that a portion of these particular individuals are more susceptible to dental caries due to changes in dental enamel that are related to amelogenin genomic variation. However, apparently amelogenin function can be impacted by inflammation, and this can lead to small changes in the structure of the dental enamel that later in life increases the risk of dental caries.

Scanning electron microscopy approach to observe bacterial adhesion to dental surfaces

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Bacterial adhesion on dental surfaces depends on the bacterial strain used.

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The magnification used for observation with a scanning electron microscope depends on the size of the bacteria to be observed.

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The quality of dental tissues is determinant in the process of bacterial adhesion.

AIM

To describe the in vitro bacterial adhesion protocol of Streptococcus mutans and Lactobacillus casei on dental surfaces for a qualitative approach by Scanning Electron Microscopy (SEM) observations. A control and Amelogenesis Imperfecta (AI) affected teeth were used to validate the protocol.

METHOD DETAILS

Eight teeth were collected and fixed in 10% formalin during 10 days. Crowns were fragmented into 4 parts and kept in the freshly prepared artificial saliva. For the preparation of bacterial suspensions, bacterial strains (S. mutans and L. casei) were incubated in a freshly prepared culture medium. After two successive cultures at 37 °C and 3 rinces, bacterial suspensions were prepared in artificial saliva and adjusted to correspond to 10⁸ CFU ml⁻¹. Bacterial adhesion was carried out by sedimentation. Dental fragments were immersed in bacterial suspensions and rinsed with PBS to remove non adherent bacteria. Adherent bacteria were fixed with glutaraldehyde. Finally, teeth samples were dehydrated, coated, dried and observed using high-resolution SEM (JEOL, JSM-5400).

RESULTS

SEM observations showed adherence of spheric stuctures, identified as S. mutans and bacilic structures identified as L. casei.

CONCLUSION

Adhesion of bacteria could be observed by SEM and depends on the quality of dental mineralized tissues.