Development of undergraduate students' diagnostic accuracy for the classification of molar incisor hypomineralization.

INTRODUCTION: 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. METHODS: 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). RESULTS: 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). CONCLUSION: Diagnostic skills to classify MIH can be developed by combining conventional theoretical classes and e-learning-assisted pre-clinical practices.

Molar Incisor Hypomineralization in adolescents and adults and its association with facial profile and occlusion.

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.

Characterization of enamel developmental defects in patients with orofacial clefts and their relationship to surgical procedures.

AIMS: This study aimed to characterize the prevalence of development defects of enamel (DDE) in patients with cleft based on the cleft phenotype and explore the relationship between surgical procedures and different types of DDE. MATERIAL AND METHODS: In this cross-sectional study, 290 standardized orthodontic documentation and medical records from a reference hospital were evaluated, which treated patients with: cleft lip (CL), cleft lip with alveolar bone involvement (CLa), cleft lip and palate (CLP), cleft palate (CP), cleft median (CM), and considering laterality as unilateral or bilateral. DDE was assessed using the Ghanim Index (2015). Information on surgical intervention periods was obtained from medical records. Statistical analyses were performed using prevalence ratio (PR) for DDE comparisons between cleft phenotypes and surgical procedures. RESULTS: The prevalence of DDE was 77.2%. Demarcated hypomineralization was associated with CP and CLP, while hypoplasia was associated with CLa, especially when bilateral. Hypoplasia was also associated with the labial adhesion surgery. CONCLUSION: Demarcated hypomineralization was the most common DDE in this population, and the cleft phenotype influenced the type of DDE manifested. The lip adhesion surgery increased the chances of hypoplasia manifestation. CLINICAL RELEVANCE: The type of DDE in patients with cleft depends on the cleft phenotype. Understanding this susceptibility enables the multidisciplinary team to monitor dental development, thus allowing early diagnosis and timely referral to the pediatric dentist and better prognoses.

Molar-Incisor Hypomineralization: Prevalence Comparative Study in 6 Years of Interval.

The aim of this study was to evaluate the prevalence evolution rate of MIH (molar-incisor hypomineralization) after a 6-year period in Araraquara/SP, Brazil. This population-based study evaluated MIH in 545 schoolchildren (6-12 years of age) and other associated alterations, dental caries and dental fluorosis (DF). A semistructured questionnaire was sent to the schoolchildren's parents/guardians with the purpose of identifying the socioeconomic profile. Associations between MIH and the clinical characteristics were analyzed by the Poisson analysis of regression with robust variance, estimating the RPc (crude prevalence ratio) with CI 95%. The level of significance of 5% was adopted. The MIH prevalence in Araraquara/SP in 2016 was 14.3% (n = 78), and at this time, an increase of 2% was observed, in comparison with the data of the first prevalence study conducted in 2010 (12.3%). The mild degree compromise was the most prevalent diagnosis in the affected teeth (82.0%). Among children with MIH, the mean number of affected teeth was 2.78. Of the total number of children with MIH, 32.0% presented alterations in both first permanent molars and permanent incisors. There is no significant association between MIH and dental caries experience on permanent dentition (PRc = 1.141; CI 95% 0.709-1.835) or on primary dentition (PR c = 1.132; CI 95% 0.749-1.709). Children with MIH presented significantly less prevalence of dental fluorosis (PR c = 0.505; CI 95% 0.268-0.950). There is no association between MIH and monthly Brazilian minimal wage income (PR c = 1.130; CI 95% 0.655-1.949). It was concluded that the number of MIH cases had increased, revealing a greater need for defining the etiological factors and establishing a correct diagnosis to make it possible to institute early intervention.

Does molar-incisor hypomineralization (MIH) affect only permanent first molars and incisors? New observations on permanent second molars.

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.

Survival of stainless-steel crowns and composite resin restorations in molars affected by molar-incisor hypomineralization (MIH).

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.

Association Between Frequency and Severity of Dental Fluorosis and Molar Incisor Hypomineralization.

OBJECTIVE: To assess the association between the frequency and severity of dental fluorosis (DF) and molar incisor hypomineralization (MIH) in a fluoridated salt region. STUDY DESIGN: 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. RESULTS: 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). CONCLUSION: MIH frequency and severity tend to be lower in the presence of DF.

Dental Fluorosis according to Birth Cohort and Fluoride Markers in an Endemic Region of Colombia.

OBJECTIVES: To analyze changes in the dental fluorosis (DF) incidence according to a birth cohort and explore current exposure to DF in a case series. METHODS: Repeated cross-sectional study of two periods: 2015 and 2018. Two standardized examiners registered DF using the Thylstrup-Fejerskov index in permanent teeth of children aged 7-18 years. Period and birth cohort frequencies were estimated by a generalized linear model, binomial family, and logarithmic link function. Period estimates are presented as prevalence ratios (PR) and birth cohort estimates as cumulative incidence ratios (RR); 95% confidence intervals and P values are reported. In a subsample of 37 volunteers (12.29 ± 2.63 years), the fluoride (F) concentration in toenails was measured using the HMDS diffusion method and an ion-specific electrode. Other samples from the local environment such as food, soil, and coal were also collected. RESULTS: In 274 children, we found that nonsignificant increases between periods (PR = 1.17; 95% CI: 0.89-1.55) were not explained by birth cohort effects. A total of 37.8% of the subsample had a toenail F concentration ≥2 µg F/g. The salty snacks and seasoning had the highest F concentrations among local environmental samples. CONCLUSION: In this population with a high DF frequency according to birth cohort and the evaluated period, the study of soil, coal, and food samples indicated a continued F exposure. F concentration found in the toenails shows a moderate F exposure; nearly a third of the children and adolescents exceeded the adopted threshold of 2 µg F/g. It is important to monitor and explore changes in exposure in highly affected population.

Clinical changes in the severity of dental fluorosis: a longitudinal evaluation.

BACKGROUND: Dental fluorosis (DF) has been one of the most prevalent pediatric dental conditions associated with aesthetic concern and treatment needs. This study aimed to identify the longitudinal clinical change in the severity of DF in 8-12-year-old children and its association with gender, age, severity, and tooth type. METHODS: This observational study assessed the dental aspects of the 92 Colombian children in 2015 (mean age at beginning 9.71 years ± 1.23) and 2018 (mean age 13.69 years ± 1.41), from an area with high DF prevalence. DF was recorded in all permanent teeth by two calibrated examiners using the Thylstrup and Fejerskov Index (TFI). DF severity change (maximum-TFI-score) was analyzed with descriptive analysis at the tooth level. Associated factors were evaluated with the generalized linear model, binomial family, and logarithmic link function. RESULTS: TFI scores ranged between 1 (very mild) to 6 (severe), being score 2 (41.7%) the most prevalent. After three years, 29.6% of the teeth presented score reduction, 24.1%, increased and 46.3% did not change; the significant association was related to increasing of the basal TFI = 1 score (44.2%) (RR = 9.7; 95% CI 1.7-56.5; p = 0.01) and with canines, premolars and second-permanent-molars teeth group (RR = 3.3; 95% CI 1.9-5.6; p = 0.005). CONCLUSION: The present study based on clinical features about DF confirms the dynamic post-eruptive nature of this condition. After three years of follow-up, a considerable proportion of the teeth changed to a higher score. Furthermore, the canines, premolars, and second-permanent-molars showed a higher incidence of an increase in severity of TFI score.

Photobiomodulation therapy for hypersensitivity associated with molar-incisor hypomineralization: a case report.

Molar-incisor hypomineralization (MIH) is a qualitative defect of the dental enamel on permanent first molars and may be associated with permanent incisors. There is currently no defined therapeutic protocol for managing the hypersensitivity associated with this condition. The present case report describes the treatment of a patient with MIH and the impact on the patient's quality of life as assessed using the Child Perceptions Questionnaire for children aged 11 to 14 years (CPQ11-14). The maxillary central incisors, maxillary and mandibular first molars, and mandibular right canine of an 11-year-old girl were compromised by MIH. The long version of the CPQ11-14 was self-administered before treatment. Initially, the patient reported hypersensitivity of her maxillary right central incisor, maxillary and mandibular left first molars, and mandibular right canine when consuming cold food and beverages. This was confirmed by applying a jet of air to the teeth and asking the patient to report the level of sensitivity using the Wong-Baker FACES Pain Rating Scale. The patient reported that hypersensitivity was present every day or almost every day. Desensitizing treatment included 4 applications of photobiomodulation therapy (infrared diode laser) and 4 applications of fluoride varnish. After desensitization, the maxillary central incisors received direct composite resin restorations, while the maxillary left first molar, which had an amalgam restoration and recurrent caries, received a resin-modified glass ionomer cement restoration. At the conclusion of the treatment, the patient completed the CPQ11-14 again and reported less difficulty with consuming hot and cold foods and beverages, indicating that treatment had reduced hypersensitivity and its negative impact on her quality of life.

Greater caries-free survival of first permanent molars: Findings from a 7-year follow-up evaluation of a community-based oral health preventive program.

BACKGROUND: The occlusal surface of the first permanent molar is the most frequently affected site by dental caries. AIM: To assess the caries-free survival of first permanent molars in children participating in a community-based oral health preventive program. DESIGN: This was a retrospective study conducted on 426 children under 12 years of age, beneficiaries of a preventive program from 2009 to 2015, in El Cedro, Colombia. The program offered oral health care education, supervised brushing and mouth washing, and application of topical fluoride. By using parametric survival models for interval-censored data, primary and secondary caries-free survival of any first permanent molar was estimated and analyzed. RESULTS: Before program implementation, dental caries lesions presented at an average age, adjusted by age of eruption, of 8.3 years for primary caries lesion and 9.3 years for secondary caries lesion. After 7 years of the program, the estimated average age for presenting primary dental caries lesion was delayed by 4.6 years and by 5.3 years for secondary caries. CONCLUSION: The implementation of the oral health program led to improved caries-free survival of first permanent molars.

Genes Regulating Immune Response and Amelogenesis Interact in Increasing the Susceptibility to Molar-Incisor Hypomineralization.

Ameloblasts are sensitive cells whose metabolism and function may be affected by inflammatory stimuli. The aim of this study was to evaluate the possible association between polymorphisms in immune response-related genes and molar-incisor hypomineralization (MIH), and their interaction with polymorphisms in amelogenesis-related genes. DNA samples were obtained from 101 nuclear families that had at least 1 MIH-affected child. Eleven single-nucleotide polymorphisms (SNPs) were investigated in immune response genes using TaqMan® technology allele-specific probes. A transmission disequilibrium test was performed to verify overtransmission of alleles in all MIH families, as well as in families only with mild or severe MIH-affected children. Gene-gene interactions between the immune-related and amelogenesis-related polymorphisms were analyzed by determining whether alleles of those genes were transmitted from heterozygous parents more often in association than individually with MIH-affected children. In severe cases of MIH, significant results were observed for rs10733708 (TGFBR1, OR = 3.5, 95% CI = 1.1-10.6). Statistical evidence for gene-gene interactions between rs6654939 (AMELX) and the SNPs rs2070874 (IL4), rs2275913 (IL17A), rs1800872 (IL10), rs1800587 (IL1A), and rs3771300 (STAT1) was observed. The rs2070874 SNP (IL4) was also significantly overtransmitted from heterozygous parents with the rs7526319 (TUFT1) and the rs2355767 (BMP2) SNPs, suggesting a synergistic effect of the transmission of these alleles with susceptibility to MIH. This family-based study demonstrated an association between variation in TGFBR1 and MIH. Moreover, the polymorphisms in immune response and amelogenesis genes may have an additive effect on the risk of developing MIH.

Caries treatment decisions among undergraduate and postgraduate students supported by visual detection systems.

BACKGROUND: The difficulties of caries diagnosis and the level of examiner's experience may influence the treatment decision, resulting excessive and inefficient intervention. AIM: This randomized experimental study evaluated caries treatment decisions made by undergraduate (UG) and postgraduate (PG) students when examination was performed through conventional visual clinical examination (CVCE) and when supported by ICDAS (IC) or Nyvad's (NY) criteria. DESIGN: Four UG and four PG initially analyzed, by CVCE, 300 primary incisors and molars surfaces of 25 children aged 5-12 years, and choose between no treatment, non-operative, and operative treatment. Students were randomized between IC (2UG; 2PG) and NY (2UG; 2PG) and, after one week of receiving training, repeated evaluations and treatment suggestions. Reference standard was established by two researchers' consensus. Sensitivity, specificity, ROC analysis, and kappa were calculated. Treatment decisions were analyzed by means of contingency tables. RESULTS: Only sensitivity showed statistical difference (P < 0.05). Operative treatment had high percentage for initial lesions at first evaluation for both criteria; second evaluation showed higher percentage of non-operative treatments for the same lesions. CONCLUSIONS: IC and NY present satisfactory performance in primary teeth by UG and PG, and their use may assistance UG to adopt a less interventionist approach for initial enamel lesions.

Eighteen-month clinical performance of composite resin restorations with two different adhesive systems for molars affected by molar incisor hypomineralization.

INTRODUCTION: The restorative management of molars with molar incisor hypomineralization (MIH) represents a challenge in the clinical practice with high failure rate. OBJECTIVE: The aim of this study is to evaluate the clinical survival of direct composite resin restorations in first permanent molars (FPMs) that are affected by MIH, comparing two adhesive systems. MATERIAL AND METHODS: We selected 41 FPMs with MIH from children aged 6-8 years. FPM fully erupted and with restorative treatment needed were the inclusion criteria. We excluded FPMs with destroyed crowns. The FPMs were randomly assigned to two groups: self-etching adhesive (SEA) and total-etch adhesive (TEA). Clinical evaluation was performed by a blinded examiner during 18 months according to the modified US Public Health Service (USPHS) criteria. The actuarial method was used to evaluate survival of the restorations, and Chi-square and Fisher's exact tests were used to compare differences between the groups (α = 5 %). RESULTS: The cumulative survival rates were 100 % at 1 month, 89 % at 6 months, 73 % at 12 months, and 68 % at 18 months in SEA, and 95 % at 1 month, 72 % at 6 months, 59 % at 12 months, and 54 % at 18 months in TEA; there was no significant difference between groups. CONCLUSIONS: There was no difference in clinical survival of restorations in FPMs affected by MIH using TEA or SEA adhesives in the end of 18 months. CLINICAL RELEVANCE: It was suggested that SEAs as well as TEAs can be applied to restore molars affected by MIH, when it is performed a conservative cavity preparation. Once, cavosurface margins (cavity design) in hypomineralized enamel have less bonding capability.

Family-Based Genetic Association for Molar-Incisor Hypomineralization.

Despite some evidence of genetic and environmental factors on molar-incisor hypomineralization (MIH), its aetiology remains unclear. This family-based genetic association study aimed more comprehensively to investigate the genetic carriage potentially involved in MIH development. DNA was obtained from buccal cells of 391 individuals who were birth family members of 101 Brazilian nuclear families. Sixty-three single nucleotide polymorphisms (SNPs) were investigated in 21 candidate genes related to amelogenesis using the TaqMan™ OpenArray™ Genotyping platform. All SNPs were genotyped in 165 birth family members unaffected by MIH, 96 with unknown MIH status and 130 affected individuals (50.7% with severe MIH). Association analysis was performed by the transmission/disequilibrium test (TDT), and statistical results were corrected using the false discovery rate. Significant results were obtained for SNPs rs7821494 (FAM83H gene, OR = 3.7; 95% CI = 1.75-7.78), rs34367704 (AMBN gene, OR = 2.7; 95% CI = 1.16-6.58), rs3789334 (BMP2 gene, OR = 2.9; 95% CI = 1.34-6.35), rs6099486 (BMP7 gene, OR = 2.2; 95% CI = 1.14-4.38), rs762642 (BMP4 gene, OR = 2.3; 95% CI = 1.38-3.65), rs7664896 (ENAM gene, OR = 2.1; 95% CI = 1.19-3.51), rs1711399 (MMP20 gene, OR = 0.4; 95% CI = 0.20-0.72), rs1711423 (MMP20 gene, OR = 2.1; 95% CI = 1.18-3.61), rs2278163 (DLX3 gene, OR = 2.8; 95% CI = 1.26-6.41), rs6996321 (FGFR1 gene, OR = 2.7; 95% CI = 1.20-5.88), and rs5979395 (AMELX gene, OR = 11.7; 95% CI = 1.63-84.74). Through this family-based association study, we concluded that variations in genes related to amelogenesis were associated with the susceptibility to develop MIH. This result is in agreement with the multifactorial idea of the MIH aetiology, but further studies are necessary to investigate more thoroughly the factors that could influence MIH.

Amoxicillin diminishes the thickness of the enamel matrix that is deposited during the secretory stage in rats.

BACKGROUND: The use of amoxicillin during early childhood has been associated with molar incisor hypomineralization. AIM: The objective of this study was to determine whether the use of amoxicillin interferes with enamel development, during secretion and early mineralization stages. DESIGN: Fifteen pregnant rats were randomly assigned to three groups that received physiological solution (sham group), 100 mg/kg/day amoxicillin (A100G), and 500 mg/kg/day amoxicillin (A500G). After birth, the pups in each group received the same treatment until post-natal day 7 or 12. The upper first molars were analyzed histomorphometrical and immunostaining with amelogenin on day 7, and MMP-20 on day 12 was performed using a semiquantitative method (H-score). RESULTS: At 7 days, several vacuolar structures were observed in the ameloblasts in the A100G and A500G groups. A significant reduction of the enamel thickness (P < 0.001) was found in amoxicillin-treated rats compared with the sham group. Significant differences were not observed in enamel thickness (P > 0.05) between the groups of 12-day-old rats. Moreover, significant differences were not observed in the number of amelogenin- and MMP-20-immunolabeled ameloblasts (P > 0.05) between groups. CONCLUSION: The present results suggest that amoxicillin interferes with the initial stages of amelogenesis by causing structural changes in the ameloblasts and a reduction of the enamel matrix.

Effect of Fluoride Varnish on Enamel Remineralization in Anterior Teeth with Molar Incisor Hypomineralization.

OBJECTIVE: The objective of this study was to investigate the effect of fluoride varnish on remineralization of anterior teeth affected by Molar-Incisor Hypomineralization (MIH) by means of Quantitative Light-Induced Fluorescence- QLF. STUDY DESIGN: Fifty-one healthy 9 - 12- year-old children were selected according to different clinically diagnosed levels of MIH, proposed by the European Academy of Pediatric Dentistry (2003) (considering the most severe lesion per patient, n= 51 lesions), and randomly divided into two groups: (1) four applications of 5% NaF varnish, with one-week interval, and (2) usual home care- control. At each visit, the mean change in fluorescence and area of lesion were measured by QLF. The data were analyzed by repeated measures ANOVA and Tukey's test. RESULTS: All patients showed enamel alterations in first permanent molars and incisors, frequently with two molars affected by MIH (41.1%). There was no statically significant difference in the mean of fluorescence and area of lesion between groups over the studied time. CONCLUSION: We observed no favorable effect on the remineralization of MIH lesions in anterior teeth after four applications of fluoride varnish.

Longitudinal Evaluation of the Structural Integrity of Teeth Affected by Molar Incisor Hypomineralisation.

The aim of this prospective cohort study was to evaluate the risk of posteruptive breakdown and the development of caries lesions in teeth with molar incisor hypomineralisation (MIH). A total of 367 permanent incisors and first molars, affected and not affected by MIH lesions, of 45 children with MIH from Araraquara, São Paulo, Brazil, were evaluated at intervals from 6 to 12 months by assessing the severity of MIH, the presence of tooth caries lesions and the treatment needed. During the study period, all patients received preventive care. The data were analysed using Fisher's exact test and actuarial method survival analysis. Significant associations were also found in teeth between the presence of MIH and a DMFT index >0 in all periods and also between the need for treatment and the presence of MIH. The teeth affected by MIH opacities were healthy in 99% of incisors and 93% of molars at the end of the 12-month period. Due to the high likelihood of maintaining the tooth structure in opacities, the complete or premature removal of the affected area is not justified.

Photodynamic antimicrobial chemotherapy on Streptococcus mutans using curcumin and toluidine blue activated by a novel LED device.

Photodynamic antimicrobial chemotherapy (PACT) is an antimicrobial approach that uses photosensitizers (PS) in combination with light sources at specific wavelengths aiming the production of reactive oxygen species. The long illumination time necessary to active PS is a challenge in PACT. Thus, this study investigated the antimicrobial effect of a novel single source of light-emitting diode (LED) light that covers the entire spectrum of visible light beyond interchangeable probes at high power intensity. Blue and red LED probes were used into different exposure times to active different concentrations of curcumin (C) and toluidine blue (T) on planktonic suspensions of Streptococcus mutans UA 159 (S. mutans). S. mutans were standardized and submitted to (1) PACT treatment at three concentrations of C and T exposure at three radiant exposures of a blue LED (BL) (C+BL+) and a red LED (RL) (T+RL+), (2) C (C+BL-) or T alone (T+RL-), (3) both LED lights (C-BL+ and T-RL+), and (4) neither PS nor LED illumination (control group: C-BL- and T-RL-). Aliquots of the suspensions were diluted and cultured on blood agar plates. The number of colony-forming units was calculated after 48 h. The groups submitted to PACT presented a lethal photokilling rate to all PS concentrations at tested dosimetries. The comparison to control group when PS and LED lights used alone demonstrated no decrease in the number of viable bacterial counts. The novel LED device in combination with curcumin and toluidine blue promoted an effective photoinactivation of S. mutans suspensions at ultrashort light illumination times.