This study aimed to compare the formation of polymicrobial biofilms using carious dentin or saliva as inoculum for application in in vitro microbiological studies on caries research. For biofilm ...growth, combined samples of infected dentin or saliva from three donors were used. The biofilms were grown on glass coverslips, under a regimen of intermittent exposure (6 h day
−1
) to 1% sucrose for 4 days. Total bacterial loads, as well as specific aciduric bacteria and mutans streptococci loads were quantified and correlated with biofilm acidogenicity and susceptibility to chlorhexidine. The data were evaluated using the Student's-t, Mann Whitney and Kruskal-Wallis tests. The two biofilms showed similar microbial loads (total bacteria, aciduric bacteria and mutans streptococci) on day 4, and high acidogenicity after 48 h and were susceptible to chlorhexidine at different time intervals. In conclusion, both dentin and saliva can be used as an inoculum in in vitro studies of processes related to biofilm formation.
Background
Currently, there is no consensus on the superiority of any material for the restorative treatment of molars affected by molar‐incisor hypomineralization (MIH).
Aim
To evaluate the survival ...of restorations with stainless‐steel crown (SSC) or composite resin (CR) in first permanent molars affected by MIH for 24 months.
Design
In this retrospective cohort study, 61 CR and 54 SSC restorations placed on molars affected by MIH of patients, aged between 7 and 10, that were treated and overseen at a university dental clinic in the period of 2017‐2020 were evaluated. The primary outcome was the failure‐free survival time. Parametric survival models were used for data censored by interval, and the comparison between SSC and CR was performed using the hazard ratio function with a 95% confidence interval.
Results
The survival of SSC and CR restorations after 24 months was 94.4% and 49.2%, respectively. This difference was influenced by the presence of previous restoration (aHR = 3.4; 95% CI: 1.2‐9.4) and cusp involvement (aHR = 4.0; 95% CI: 1.5‐11.2).
Conclusion
In molars with MIH and the need for restorative treatment, SSC had a significantly higher survival rate than CR over 24 months.
Background
The second permanent molar plays an important role when considering extraction of first permanent molars severely affected by molar‐incisor hypomineralization (MIH).
Aim
To assess the ...association between MIH and enamel hypomineralization of the second permanent molars in terms of presence and severity.
Design
In this retrospective cross‐sectional study, permanent teeth were evaluated in 453 patients between the ages of 13 and 16 at a dental clinic, using intraoral photographs. A calibrated examiner classified enamel hypomineralization using the MIH index and dental caries experience using the DMFT and DMFS indices. Statistical analyses were performed using a linear generalized model and ordinal logistic regression.
Results
The most commonly affected teeth by enamel hypomineralization were permanent molars, whereas incisors, premolars, and canines were less affected. The presence of severe defects in the first permanent molars was associated with mild defects in the second permanent molars (OR = 4.01; 95% CI: 2.50‐7.77). Enamel hypomineralization was associated with increased caries experience (PR = 5.54; 95% CI: 3.81‐9.06).
Conclusion
Enamel hypomineralization mainly affects the first and second permanent molars. Mild defects in the second permanent molars tend to be more frequent in patients with severe MIH in the first permanent molars. The presence of enamel hypomineralization was associated with higher dental caries experience.
To assess the association between the frequency and severity of dental fluorosis (DF) and molar incisor hypomineralization (MIH) in a fluoridated salt region.
In this retrospective cross-sectional ...study, we evaluated the buccal, occlusal/incisal, and palatal/lingual surfaces of first permanent molars and permanent incisors of 453 patients aged 13-16 years through intraoral standardized photographs. Two standardized examiners evaluated DF and MIH independently, utilizing the Thylstrup-Fejerskov (TF) index and the MIH index. The statistical analysis was performed using a generalized linear model and logistic regression adjusted for age, sex, and dental caries experience.
The MIH frequency at the surface level was lower in the presence of DF (PR= 0.03; P= 0.00, 95% CI: 0.01-0.08). At the surface level, MIH severity was lower among those presenting mild DF (aOR= 0.02; 95% IC: 0.01-0.07). Regarding severe DF, we found no significant difference in MIH severity (P= 0.174).
MIH frequency and severity tend to be lower in the presence of DF.
One of the major difficulties with respect to molar incisor hypomineralization (MIH) is its classification and differentiation from other enamel development defects (EDDs). The aim of this study was ...to evaluate diagnostic accuracy in dental students to classify MIH as well as its differentiation from other EDDs by combining conventional theoretical classes and e-learning-assisted pre-clinical practices.
In this one-group pre-test and post-test study, 59 second-year students assessed 115 validated photographs using the MIH Index on the Moodle learning platform. This index assesses the clinical features and extent of MIH, differentiating it from other EDDs. Students received automatic feedback after the pre-test. Two weeks later, students re-evaluated the same photographs. Both pairwise accuracy and overall diagnostic accuracy were estimated and compared for pre- and post-testing, with the area under the curve AUC, along with 95% confidence intervals (95% CI).
The lowest diagnostic accuracy was for the ability to discriminate between white or cream-coloured demarcated opacities and hypomineralization-type defect that is not MIH. The overall pre-test accuracy was AUC = 0.83 and increased significantly post-test to AUC = 0.99 (p < .001). The overall accuracy to discriminate the extent of the lesion also increased significantly post-test (p < .001).
Diagnostic skills to classify MIH can be developed by combining conventional theoretical classes and e-learning-assisted pre-clinical practices.
The study of bacterial interaction between Streptococcus mutans and Actinomyces naeslundii may disclose important features of biofilm interspecies relationships. The aim of this study was to ...characterize-with an emphasis on biofilm formation and composition and metabolic activity-single- and dual-species biofilms of S. mutans or A. naeslundii, and to use a drip flow reactor (DFR) to evaluate biofilm stress responses to 0.2% chlorhexidine diacetate (CHX). Single- and dual-species biofilms were grown for 24 h. The following factors were evaluated: cell viability, biomass and total proteins in the extracellular matrix, 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide-"XTT"-reduction and lactic acid production. To evaluate stress response, biofilms were grown in DFR. Biofilms were treated with CHX or 0.9% sodium chloride (NaCl; control). Biofilms were plated for viability assessment. Confocal laser-scanning microscopy (CLSM) was also performed. Data analysis was carried out at 5% significance level.
viability and lactic acid production in dual-species biofilms were significantly reduced.
showed a higher resistance to CHX in dual-species biofilms. Total protein content, biomass and XTT reduction showed no significant differences between single- and dual-species biofilms. CLSM images showed the formation of large clusters in dual-species biofilms. In conclusion, dual-species biofilms reduced
viability and lactic acid production and increased
resistance to chlorhexidine.
This article reviews the indications, objectives and step by step process of the Modified Hall Technique in the management of primary and permanent molars affected by severe enamel ...hypomineralization. Scientific based biological principles are discussed in order to provide relevant clinical information for Pediatric and General dentists in order to provide support for the safe use the technique in clinical practice.
Objectives
To date, there are no data available in the scientific literature about the diagnosis of Molar Incisor Hypomineralization (MIH) in adults. We aimed to assess the MIH prevalence and ...clinical characteristics in adolescents and adults and its association with facial profile and occlusion.
Materials and methods
In this cross-sectional study, permanent teeth were evaluated in 275 patients between the ages of 12 and 49 at a dental clinic, using intraoral photographs. A calibrated examiner classified enamel hypomineralization using the MIH index. Statistical analyses were performed using chi-square, Fisher’s tests, and ordinal logistic regression.
Results
MIH was observed in 12.73% of all patients. The most commonly affected teeth were permanent molars, while incisors, premolars, and canines were less affected. MIH usually appears as demarcated opacities, with less than one-third of the tooth affected. There was no association between severe defects and facial profile and occlusion, but rather with the higher age of the participants.
Conclusion
Enamel hypomineralization mainly affects the first and second permanent molars, but it could also be observed in the third molars, although it is not associated with the orthodontic characteristics investigated.
Clinical relevance
This is the first study to highlight the prevalence of MIH in adults. This result showed the importance of other specialists beyond Pediatric Dentistry in the diagnosis of this defect. In addition, hypomineralization of other permanent teeth (canines, premolars, and second molars) has been described previously in other studies, but this is the first to identify MIH in third molars.
The use of controlled drug delivery systems represents an alternative and promising strategy for the use of antimicrobials in the oral cavity. Microparticles, films and oral tablets based on alginate ...and gellan gum were developed also as a strategy to overcome the low aqueous solubility of morin. The systems were characterized in terms of morphological characteristics, mucoadhesion and in vitro drug release. Antibiofilm activity was analyzed for acidogenicity, microbial viability and the composition of the extracellular matrix of single-species biofilms. Scanning Electron Microscopy demonstrated that the microparticles were spherical, rough and compact. The film and the tablet presented smooth and continuous surface and in the inner of the tablet was porous. These systems were more mucoadhesive compared to the microparticles. The in vitro morin release profiles in artificial saliva demonstrated that the microparticles controlled the release better (39.6%), followed by the film (41.1%) and the tablet (91.4%) after 20 h of testing. The morin released from the systems reduced the acidogenicity, microbial viability, concentration of insoluble extracellular polysaccharides and dry weight of biofilms, when compared to the control group. The findings of this study showed that the morin has antibiofilm activity against cariogenic microorganisms.
•Systems based on alginate or gellan gum controlled the release rate of morin.•Microparticles, films and lyophilized tablets polysaccharide-based were mucoadhesive.•The morphology of the delivery systems influenced the release rate of morin.•The morin released presented antibiofilm activity against cariogenic microorganisms.•The morin released from the systems reduced the extracellular matrix of biofilms.
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