Frequency of BRAF V600E immunoexpression in ameloblastomas: a multi-institutional analysis of 86 cases in Latin America and comprehensive review of the literature

BACKGROUND

The initiation of odontogenic tumorigenesis often involves the activation of the MAP-kinase pathway, with a pivotal role played by the BRAF V600E mutation. This study aimed to investigate the frequency of BRAF V600E immunoexpresion in ameloblastomas diagnosed in four Latin American centers and correlate this finding with the histological types and subtypes of the analyzed cases.

MATERIAL AND METHODS

A total of 86 samples of ameloblastomas were examined for immunohistochemistry using anti-BRAF V600E antibody. The histopathological features of each case were analyzed.

RESULTS

 Positivity for anti-BRAF V600E antibody was detected in 65/86 cases (75.6%). BRAF V600E was positive in 38/56 cases (67.9%) of conventional ameloblastomas and in 27/30 cases (90.0%) of unicystic ameloblastomas. A statistically significant difference in BRAF V600E positivity was observed when comparing unicystic ameloblastomas to conventional ameloblastomas (p=0.03). No statistically significant difference in BRAF V600E positivity was observed when comparing histological variants, both for conventional ameloblastomas and unicystic ameloblastomas.

CONCLUSIONS

This study highlights a high frequency of BRAF V600E immunoreactivity in ameloblastomas among Latin American cases. The prevalence of the BRAF V600E immunoexpresion may suggest the feasibility of utilizing BRAF-targeted therapy for ameloblastomas with this mutation.

DNA oxidative damage in oral cancer: 8-hydroxy-2´-deoxyguanosine immunoexpression assessment

BACKGROUND

The development and establishment of oral squamous cell carcinoma are confined to carcinogenesis, which involves oxidative stress via oxygen-free radical production as a hydroxyl radical (HO•), considered the most important cause of oxidative damage to basic biomolecules since it targets DNA strands. 8-Hydroxy-2´-deoxyguanosine (8-OHdG) is considered a free radical with a promutagenic capacity due to its ability to pair with adenosine instead of cytosine during replication.

MATERIAL AND METHODS

We collected 30 paraffin-embedded tissue samples of OSCC from patients treated between 2013 and 2018. We recorded risk habits, disease stage, disease free survival and death with at least 3 years of follow-up. 8-Hydroxyguanosine was evaluated by immunohistochemistry and subsequently classified as weak-moderate or strong positive expression. Additionally, we noted whether it was expressed in the cytoplasm and/or nucleus.

RESULTS

Most of the cases expressed 8-OHdG with a strong intensity (80%). All neoplastic cells were preferentially stained in only the cytoplasm (70.0%), but nuclear positivity was found in 30%, independent of the intensity. Based on the location in the cytoplasm and/or nucleus, tumors >4 cm showed a high frequency (95.5%) of 8-OHdG expression in only the cytoplasm, with a significant difference (p value 0.001). Additionally, overall survival was affected when immunoexpression was present in the cytoplasm and nucleus because all deaths were in this group were statistically significant (p value = 0.001).

CONCLUSIONS

All tumors showed DNA oxidative damage, and 8-OHdG was preferentially expressed in the cytoplasm. This finding was associated with tumor size and, when present in the nucleus, might also be related to death.

[Polymorphisms associated with dental caries in pediatric populations: a systematic review]

Single nucleotide polymorphisms (SNPs) have been reported to play an important role in the etiology of dental caries. The aim of this research was, through a systematic review, to identify SNPs recently associated with dental caries in pediatric populations. We included studies performed in humans up to 18 years of age that evaluated the relationship between SNPs and dental caries from 2017 to 2022. Articles that covered other study variables were excluded. PubMed, ScienceDirect and Web of Science were used to search for information and the included articles were evaluated with one of the Joanna Briggs Institute's tools. Twenty-five articles were selected, 60% of which were given high methodological quality. A total of 10,743 research subjects, ranging in age from 20 months to 17 years, participated in the study. The SNPs considered risk factors were identified in the genes miRNA202, VDR, AMELX, TUFT1, KLK4, MBL2, ENAM, DEFB1, HLA-DRB1, TAS1R1, DSPP, RUNX2 and MMP13; those considered protective factors were identified in the genes MMP20, AMBN, MMP9, TIMP2, TNF-α, VDR, IL1B, ENAM and HLA-DRB1. This systematic review presents the genetic polymorphisms that are associated with the etiology of caries in children and adolescents, some of which act as risk factors and others as protective factors against the disease.

Bactericidal Activity of Silver Nanoparticles on Oral Biofilms Related to Patients with and without Periodontal Disease

BACKGROUND AND OBJECTIVES

Periodontal disease (PD) is a multifactorial oral disease regularly caused by bacterial biofilms. Silver nanoparticles (AgNP) have offered good antimicrobial activity; moreover, there is no available scientific information related to their antimicrobial effects in biofilms from patients with PD. This study reports the bactericidal activity of AgNP against oral biofilms related to PD.

MATERIALS AND METHODS

AgNP of two average particle sizes were prepared and characterized. Sixty biofilms were collected from patients with (30 subjects) and without PD (30 subjects). Minimal inhibitory concentrations of AgNP were calculated and the distribution of bacterial species was defined by polymerase chain reaction.

RESULTS

Well-dispersed sizes of AgNP were obtained (5.4 ± 1.3 and 17.5 ± 3.4 nm) with an adequate electrical stability (-38.2 ± 5.8 and -32.6 ± 5.4 mV, respectively). AgNP showed antimicrobial activities for all oral samples; however, the smaller AgNP had significantly the most increased bactericidal effects (71.7 ± 39.1 µg/mL). The most resistant bacteria were found in biofilms from PD subjects (p < 0.05). P. gingivalis, T. denticola, and T. forsythia were present in all PD biofilms (100%).

CONCLUSIONS

The AgNP showed efficient bactericidal properties as an alternative therapy for the control or progression of PD.

Etiological Factors of Molar Incisor Hypomineralization: A Systematic Review and Meta-Analysis

Molar incisor hypomineralization (MIH) is a defect of the dental enamel that predominantly affects first molars and permanent incisors. Identifying the significant risk factors associated with MIH occurrence is essential for the implementation of prevention strategies. The purpose of this systematic review was to determine the etiological factors associated with MIH. A literature search was carried out from six databases until 2022; it covered pre-, peri-, and postnatal etiological factors. The PECOS strategy, PRISMA criteria, and the Newcastle-Ottawa scale were used, and 40 publications were selected for qualitative analysis as well as 25 for meta-analysis. Our results revealed an association between a history of illness during pregnancy (OR 4.03 (95% CI, 1.33-12.16), p = 0.01) and low weight at birth (OR 1.23 (95% CI, 1.10-1.38), p = 0.0005). Furthermore, general illness in childhood (OR 4.06 (95% CI, 2.03-8.11), p = 0.0001), antibiotic use (OR 1.76 (95% CI, 1.31-2.37), p = 0.0002), and high fever during early childhood (OR 1.48 (95% CI, 1.18-1.84), p = 0.0005) were associated with MIH. In conclusion, the etiology of MIH was found to be multifactorial. Children with health disorders in the first years of life and those whose mothers underwent illnesses during pregnancy might be more susceptible to MIH.

A Systematic Review and Meta-Analysis of the Relationship Between the Severity of Dental Fluorosis and Fluoride Biomarkers in Endemic Areas

The intake of high concentrations of fluoride, mainly through drinking water, diet and fluoridated dentifrices, produces fluorosis, which in its early stages is manifested as dental fluorosis (DF). To recognize exposure to fluoride in endemic areas and to evaluate the risk of developing health impairment, the WHO has established several biomarkers that are used to determine systemic fluorine (F^-) exposure. Thus, the aim of this study was to conduct a systematic review and meta-analysis of the relationship between the severity of DF and fluoride biomarkers in endemic areas. The protocol of this study was previously registered as CRD42021244974. A digital search was carried out in PubMed/Medline, SpringerLink, Scopus, Cochrane and Google Scholar by employing the keywords "urine", "nails", "hair", "plasma", "saliva" and "dental fluorosis" for the original studies with content associated with F^- for the biomarkers and DF. The mean difference was established as the effect measure for the meta-analysis. Seven studies fulfilled the eligibility criteria, among which five assessed urine and two employed nails as fluoride biomarkers. A positive significant difference was found between the biomarkers and the severity of DF (0.27, p < 0.001) and individually for each biomarker (urine: 0.14, p = 0.001; nails: 0.88, p < 0.05). The F^- concentration in urine and nails is correlated with the severity of DF, with the most evident differences between healthy individuals and those with mild severity. Both biomarkers are adequate to assess this relationship in endemic areas of fluoride and DF.

Connexin 43 expression in tooth germ and benign odontogenic tumors

OBJECTIVE

The aim of this study was to investigate and compare the immunohistochemical expression of connexin 43 (Cx43) in tooth germs (TGs), ameloblastic fibromas (AFs), ameloblastic fibro-odontomas (AFOs), and conventional ameloblastomas (AMs).

STUDY DESIGN

Nine TGs, 12 AFs, 12 AFOs, and 27 AMs were evaluated for Cx43 expression by immunohistochemistry.

RESULTS

Most of the TGs expressed Cx43 in the mesenchyme (77.6%) and in the late stages of odontogenesis. Cx43 was more highly expressed (P < .05) in the mesenchymal layer of all groups than in the epithelial layer except for the AFOs. When comparing the expression of Cx43 in the different layers of the analyzed groups, statistically significant differences were observed between AFO vs AM (*P = .0158) in the epithelial layer and between AF vs AFO (P** = .0046) in the mesenchymal layer.

CONCLUSIONS

The results obtained in this study showed that Cx43 is a protein with important expression in the mesenchymal layer of the embryonic and odontogenic tissues studied. It could be speculated that Cx43 participates in mineralization events based on the relationship of the expression of this protein between the epithelial and mesenchymal layers of odontogenic tissues.

Single Nucleotide Polymorphisms and Dental Fluorosis: A Systematic Review

Genetic factors contribute to susceptibility and resistance to fluoride exposure. The aim of this systematic review was to identify alleles/genotypes of single nucleotide polymorphisms (SNPs) associated with dental fluorosis (DF) and to identify them as protective or risk factors. PubMed, ScienceDirect, Cochrane Library, Scopus and Web of Science were searched for articles; the last search was performed in August 2022. Human studies that analyzed the relationship between SNPs and DF published in English were included; systematic reviews and meta-analyses were excluded. Methodological quality was graded using the Joanna Briggs Institute checklist and risk of bias was assessed using the Cochrane Collaboration's tool. Eighteen articles were included, 44% of which showed high methodological quality and data from 5,625 participants aged 6 to 75 years were analyzed. The SNPs COL1A2, ESR2, DLX1, DLX2, AMBN, TUFT1, TFIP11, miRNA17, and SOD2 were considered risk factors, and ESR1, MMP20, and ENAM were considered protective factors. In conclusion, there are alleles and genotypes of different single nucleotide polymorphisms involved in increasing or decreasing the risk of developing dental fluorosis.

Local Tramadol Improves the Anesthetic Success in Patients with Symptomatic Irreversible Pulpitis: A Meta-Analysis

Symptomatic irreversible pulpitis is a painful clinical condition with a broad inflammatory component. Dental anesthesia in these patients is affected by the inflammatory process, reporting a high incidence of anesthesia failure. The aim of this systematic review and meta-analytical evaluation was to determine the effect of pre-treatment with tramadol in patients with symptomatic irreversible pulpitis, as well as for pain control and adverse effects. This study was registered in PROSPERO (ID: CRD42021279262). PubMed was consulted to identify clinical investigations comparing tramadol and placebo/local anesthetics in patients with symptomatic irreversible pulpitis. Data about the anesthesia, pain control, and adverse effects were extracted. Both the anesthetic success index and the adverse effects of local tramadol and placebo were compared with the Mantel−Haenszel test and odds ratio. Data analysis showed that the local administration of tramadol increased the anesthetic success rate when compared to placebo in patients with symptomatic irreversible pulpitis (n = 228; I2 = 0; OR = 2.2; 95% CIs: 1.30 to 3.79; p < 0.004). However, local administration of tramadol increased the risk of adverse effects when compared to placebo/local anesthetics (n = 288; I2 = 0; OR = 7.72; 95% CIs: 1.37 to 43.46; p < 0.02). In conclusion, this study shows that the local administration of tramadol increases the anesthetic success index when compared to placebo in patients with symptomatic irreversible pulpitis.

Ep-CAM (MOC-31) expression in tooth germ and ameloblastoma

BACKGROUND

Ep-CAM, a transmembrane glycoprotein expressed in most epithelium in normal conditions, has diverse roles in these tissues, including in cell adhesion, proliferation, differentiation, cell cycle regulation, migration and intracellular signaling. It is also over-expressed in most malignant neoplasia, participating in the initiation, progression, and metastatic dissemination of the tumor. The expression and roles of this protein in oral neoplasia, particularly in odontogenic tumors, remain unestablished. The objective of this study consisted in analyzing the expression of this protein in ameloblastoma and tooth germ.

MATERIAL AND METHODS

Ep-CAM (MOC-31) expression was evaluated by immunohistochemistry in tooth germs (TG) (n = 16) ameloblastomas (AM) (n = 60) and 2 ameloblastic carcinomas. Sections were visualized in their totality with an optical microscope, and positivity observed in cell membrane and cytoplasm was graded according to the following semi-quantitative scale: Neg, "essentially unstained", for negative sections or staining <5% of cells; + for staining of 5-50% of cells; ++ for staining >50% of cells.

RESULTS

Most tooth germs expressed MOC-31 (81.3%), strong staining was observed both in the inner epithelium of the enamel organ and in the adjacent stellate reticulum. 16.7% of the AM cases showed MOC-31 expression, the immunoexpression expression was diffuse at the cytoplasmic and membrane level. The only two cases of ameloblastic carcinoma included were strong positive to MOC-31. No correlation was observed between protein expression and gender, age, clinical variants, or histological subtypes.

CONCLUSIONS

Overexpression was found in TG and ameloblastic carcinoma compared to AM; further studies with different experimental strategies are suggested to clarify the biological significance of this finding.

Self-Reported Periodontal Disease and Its Association with SARS-CoV-2 Infection

Introduction: Knowledge of the oral manifestations associated with SARS-CoV-2 infection, the new coronavirus causing the COVID-19 pandemic, was hindered due to the restrictions issued to avoid proximity between people and to stop the rapid spread of the disease, which ultimately results in a hyperinflammatory cytokine storm that can cause death. Because periodontal disease is one of the most frequent inflammatory diseases of the oral cavity, various theories have emerged postulating periodontal disease as a risk factor for developing severe complications associated with COVID-19. This motivated various studies to integrate questions related to periodontal status. For the present work, we used a previously validated self-report, which is a useful tool for facilitating epidemiological studies of periodontal disease on a large scale. Methodology: A blinded case-control study with participants matched 1:1 by mean age (37.7 years), sex, tobacco habits and diseases was conducted. After the diagnostic samples for SARS-CoV-2 detection were taken in an ad hoc location at Guadalajara University, the subjects were interviewed using structured questionnaires to gather demographic, epidemiological and COVID-19 symptom information. The self-reported periodontal disease (Self-RPD) questionnaire included six questions, and subjects who met the criteria with a score ≥ 2 were considered to have periodontal disease. Results: In total, 369 participants were recruited, with 117 participants included in each group. After indicating the subjects who had self-reported periodontal disease, a statistically significant difference (p value ≤ 0.001) was observed, showing that self-reported periodontal disease (n = 95, 85.1%) was higher in SARS-CoV-2-positive individuals than in controls (n = 66, 56.4%), with an OR of 3.3 (1.8-6.0) for SARS-CoV-2 infection in people with self-reported periodontal disease. Cases reported a statistically higher median of symptoms (median = 7.0, Q₁= 5.5, Q₃ = 10.0) than controls (p value ≤ 0.01), and cases with positive self-RPD had a significantly (p value ≤ 0.05) higher number of symptoms (median = 8.0, Q₁ = 6.0, Q₃ = 10.0) in comparison with those who did negative self-RPD (median = 6.0, Q₁ = 5.0, Q₃ = 8.0). Conclusions: According to this study, self-reported periodontal disease could be considered a risk factor for SARS-CoV-2 infection, and these individuals present more symptoms.

Urinary fluoride and micronutrients intake in children from San Luis Potosi, Mexico

To assess the relationship between urinary fluoride and micronutrients intake we recruited 121 schoolchildren from San Luis Potosí. We evaluated fluoride concentrations in drinking water and urine with the ion-selective electrode method and estimated calcium, magnesium, and phosphorus intakes with a validated consumption frequency questionnaire. About 72% of the population used tap water for drinking and cooking. Fluoride concentrations were 2.36 ± 0.02 mg/L in tap water, 0.14 ± 0.04 mg/L in bottled water and 2.05 ± 0.62 mg/L in urine. Urinary fluoride was higher in children with a consumption <50% of the Recommended Daily Intake (RDI) of calcium (2.20 v/s 1.96 mg/L; p < 0.05), <50% RDI of magnesium (2.58 v/s 1.96 and 1.90 mg/L; p < 0.05) and >150% RDI of phosphorus (2.43 v/s 1.82 mg/L; p < 0.05). These data indicated that fluoride concentration in tap water is higher than bottled water and estimated micronutrients intake is related to urinary fluoride.

[Fluorides in water for consumption in northern and western Mexico]

The amount of fluoride in water in some regions of Mexico represents a public health problem. The aim of this study was to conduct a systematic review of original studies that report fluoride levels in tap and bottled water from the northern and western regions of Mexico. A systematic review was conducted using the PRISMA method in PubMed, Scopus, Medigraphic and Scielo databases. The keywords fluoride OR fluorosis AND water AND Mexico were used for the search and the records found were included and excluded according to the previous established criteria. We reviewed data in articles published between January 1st, 2010 and March 30th, 2021. We identified a total of 36 records. Most showed data found in the western region (n = 23), while the rest reported data found in the north. Both regions reported maximum and mean sample ranges above those suggested by the World Health Organization and national regulations. According to the analyzed data, in Mexico, the northern and western regions of the country show a concerning situation due to the high levels of fluoride reported by many authors in tap and bottled water. Almost all authors reported data above those recommended for national and international regulations, which represent an important public health problem that requires attention.

Association of Age and Temperamental Traits with Children's Behaviour during Dental Treatment

During paediatric dental treatment, cooperation by children is essential, and temperament can determine their behaviour style. This study aimed to associate temperamental traits and age with behaviour during paediatric dental treatment. This was an observational and cross-sectional study of patients aged 3-10 years. To determine the temperamental traits, an Emotionality Activity and Sociability Temperament Survey (EAS) was performed with the children's parents. The type of behaviour was determined with Frankl's criteria. The total scores for temperamental traits, means, and standard deviations were obtained. The chi-squared test, one-way ANOVA and Student's t-test were applied. A total of 140 patients, who were 5 ± 2.1 years old, participated in the study. Age was determinant for negative behaviour, with a greater frequency in children ≤5 years old (p < 0.05), and a significant negative correlation between age and behaviour (rho = -0.245, p = 0.001). Patients with higher emotionality and activity presented negative and definitely negative behaviours more frequently (p < 0.01). The values for sociability and shyness were similar for positive or negative behaviours. In conclusion, the temperamental traits of emotionality and activity were more frequent in children with disruptive behaviours; therefore, conducting a survey on temperamental traits can be useful for planning behavioural approaches in paediatric dentistry.

Perilipin 1 and adipophilin immunoexpression suggests the presence of lipid droplets in tooth germ, ameloblastoma, and ameloblastic carcinoma

BACKGROUND

Increased lipogenesis and lipid droplet accumulation are observed in diverse tumors, and these processes are associated with poor prognosis in several tumors, representing potential therapeutic targets. The presence of lipid droplets in odontogenic tissues and/or tumors is unknown.

METHODS

Immunohistochemistry for perilipin 1 and adipophilin was performed in 12 human tooth germs (TG), 27 conventional ameloblastoma (AM), and 8 ameloblastic carcinoma (AC) samples. Cytoplasmic staining was analyzed using an immunoreactive score (IRS), and the results were compared for the TG, AM, and AC samples by Kruskal-Wallis test followed by Dunn's post-test and confirmed by Mann-Whitney U test.

RESULTS

Perilipin 1 was negative in 91.7% of the TG samples, positive in 48.2% of the AM samples, and positive in 87.5% of the AC samples. Adipophilin was positive in 100% of the TG samples, 92.6% of the AM samples, and 100% of the AC samples. The perilipin 1 and adipophilin IRS revealed statistically significant differences between the TG, AM, and AC samples (p = .007 and p = .018, respectively). The perilipin 1 levels among the TG and AC samples were statically significant (**p = .0085), as well as the adipophilin levels when TG and AM samples were compared (**p < .0029).

CONCLUSIONS

Adipophilin exhibits significant activity in human tooth development. The immunoexpression of perilipin 1 and adipophilin in the AM and AC samples suggests the presence of lipid droplets, providing further evidence of metabolic alterations in these tumors. Additional studies with larger samples and alternative techniques are necessary to confirm these findings.

Body Mass Index and Dental Caries, a Five-Year Follow-Up Study in Mexican Children

There are conflicting reports on a possible association between body mass index (BMI) and caries. Given the ongoing worldwide increase in obesity, we undertook a 5-year follow-up study on 201 Mexican schoolchildren to analyse their BMI and dental caries experience. The children's weight and height were recorded, and their BMI was calculated using the WHO tables. Decayed, missing, and filled surfaces in both dentitions (dmf/DMFS) were assessed annually according to WHO criteria by two calibrated researchers (Kappa value 0.92 p < 0.001). The means, standard deviation, an ANOVA, and Student's t-test were calculated to analyse the relationship between the variables. At baseline, the children had an average of 6.5 ± 0.5 years, a BMI of 17.2 ± 3.1 (CI_95% 16.8-17.6). Their weight's classifications were 61% normal, 19% obese, 17% overweight, and 3% showed thinness. At the end of the study, their BMI were 20.6 ± 4.4 (CI_95% 19.8-21.5), 53% normal, 15% obese, 30% overweight, and 2% thin. The children's dmfs decreased from 5.8 ± 9.2 to 1.8 ± 3.4 and the DMFS increased from 0.07 ± 05 to 1.4 ± 2.3. In this population based on a 5-year follow-up, caries prevalence and incidence were not significantly associated with the BMI. However, schoolchildren with malnutrition had the highest caries indexes.

Epithelial-Mesenchymal Transition Associated with Head and Neck Squamous Cell Carcinomas: A Review

Head and neck squamous cell carcinomas (HNSCCs) are aggressive, recurrent, and metastatic neoplasms with a high occurrence around the world and can lead to death when not treated appropriately. Several molecules and signaling pathways are involved in the malignant conversion process. Epithelial-mesenchymal transition (EMT) has been described in HNSCCs, a major type of aggressive carcinoma. EMT describes the development of epithelial cells into mesenchymal cells, which depends on several molecular interactions and signaling pathways that facilitate mesenchymal conversion. This is related to interactions with the microenvironment of the tumor, hypoxia, growth factors, matrix metalloproteinases, and the presence of viral infections. In this review, we focus on the main molecules related to EMT, their interactions with the tumor microenvironment, plasticity phenomena, epigenetic regulation, hypoxia, inflammation, their relationship with immune cells, and the inhibition of EMT in the context of HNSCCs.

Screening test for COVID-19 in dental practice: Best options

PURPOSE

To review diverse tests that could serve as a screening tool for the dental community to identify patients with potential COVID-19.

METHODS

Detailed automated searches of Medline, PubMed and EBM Review, including ACP Journal Club, the Cochrane Controlled Trials Register, and the Cochrane Database of Systematic Reviews of Effectiveness from 2019 to 2020 were conducted. Real-time polymerase chain reaction (RT-PCR) or quantitative (q) RT-PCR and Western blot assays were excluded.

RESULTS

Real time loop-mediated isothermal amplification (RT-LAMP) and Real time recombinase polymerase amplification (RT-RAP) are the most promising methodologies developed as screening tools, and could be a screening test option in dental practice to identify patients potentially carrying SARS-CoV-2 and to prevent cross-infection between patients and dental personnel.

CLINICAL SIGNIFICANCE

Biological risk management in the dental clinic is primarily focused on the wearing of protective equipment by dental personnel and disinfection/sterilization procedures for surfaces. With the absence of suitable antiviral drugs or vaccines, simple, rapid, and reliable detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could be critical for preventing the spread of infection in dental practices.

Immunoexpression of galectin-3 and its potential relation to hypoxia-inducible factor-1α in ameloblastomas

In tumor biology, hypoxia triggers signaling pathways that induce transcription of genes related to angiogenesis, metastasis, glucose metabolism and apoptosis. We investigated the expression of hypoxia related proteins, galectin-3 (Gal-3) and hypoxia-inducible factor-1α (HIF-1α), in conventional (CA) and unicystic ameloblastomas (UA). We applied immunohistochemistry for Gal-3 and HIF-1α to 72 cases of ameloblastoma: 59 cases of CA and 13 cases of unicystic UA. Immunoexpression was evaluated semiquantitatively. Gal-3 expression was observed in 40% of the cases: 23/59 CA and 6/13 UA. HIF-1α immunostaining was observed in 55% of cases: 36/59 CA and 4/13 UA. 19 CA and 2 UA were positive for both markers. Immunostaining was evident in the center of the tumor islands, which exhibited squamous metaplasia or cystic degeneration. The expression of Gal-3 and HIF-1α in ameloblastomas could be interpreted as a response to hypoxic stress. Co-expression of both proteins in CA may suggest a potential interaction that participates in the biological behavior of this ameloblastoma variant.

Expression of caveolin-1 in tooth germ, ameloblastoma and ameloblastic carcinoma

BACKGROUND

The caveolin-1 protein (structural component of membrane caveolae) plays important roles in several biological functions, such as endocytosis, cell adhesion, and cell signaling. However, this protein has been associated with mechanisms of tumorigenesis in several neoplasms. The expression patterns and roles of caveolin-1 in the oral epithelium and in embryonic and odontogenic tumor tissues are still unclear.

MATERIAL AND METHODS

The expression of caveolin-1 was evaluated in samples of the normal gingival epithelium (n=7), human tooth germ (TG) (n=12), ameloblastoma (AM) (n=83), and ameloblastic carcinoma (AC) (n=9) by immunohistochemistry. Additionally, AM samples were analyzed by qRT-PCR and Western blot.

RESULTS

Most TG (91.7%), AM (73.5%) and AC (100%) samples showed diverse patterns of immunohistochemical positivity for caveolin-1, while only one gingival sample was positive. The transcript levels of cav-1 were significantly upregulated by 14.9-fold in AM tissue (P = 0.0014) compared to those in normal gingival epithelial tissue, as shown by qRT-PCR. Presence of caveolin-1 protein was confirmed by Western blot analysis. The caveolin-1 immunoexpression patterns throughout the stages of TG show its importance during odontogenesis.

CONCLUSIONS

The overexpression of caveolin-1 in AM and AC compared to its expression in normal gingival epithelium (adult tissue) suggests a possible role of caveolin-1 in protumoral events, but due to the similar immunoexpression observed in AM and AC, caveolin-1 may not necessarily participate in the malignant transformation process. However, future studies are needed to clarify and confirm these hypotheses.

Recent Biomarkers for Monitoring the Systemic Fluoride Levels in Exposed Populations: A Systematic Review

Fluorides are compounds that can be found in the minerals of soil with volcanic rocks. Different populations are exposed to high levels of fluorides through drinking water that, due to their chronic intake, cause several types of damage to health. Nails and hair, denominated as recent biomarkers, have been employed for monitoring systemic fluoride from long-term exposure to fluorides. The aim of this study was to perform a systematic review of the use of recent biomarkers for monitoring systemic fluoride levels in exposed populations and verify their validity in the measurement of the fluorine (F^-) concentration within the body. A digital search was performed in the databases PubMed/Medline, Springer Link, Cochrane, and Scopus of original articles that employed recent biomarkers for monitoring systemic F^-. Seventeen articles were included in this analysis; the recorded variables were the F^- amount in each assessed biomarker, source of exposure, and total daily fluoride intake (TDFI). TDFI was associated with F^- in nails and hair, as well as the exposure through drinking water. In conclusion, recent biomarkers are adequate for monitoring the systemic fluoride levels by evaluating the chronic/subchronic exposure through different sources, mainly drinking water, considering nails better than hair for this purpose.

ENAM Gene Variation in Students Exposed to Different Fluoride Concentrations

The ENAM gene is important in the formation of tooth enamel; an alteration can affect the lengthening of the crystals, and the thickness in enamel. The objective was to determine the presence of the single nucleotide variant (SNV) rs12640848 of the ENAM gene in students exposed to different concentrations of fluoride.

METHODS

A cross-sectional study was conducted on students exposed to high concentrations of fluoride in the city of Durango which were divided according to the severity of fluorosis and dental caries. Genotype determination was performed by DNA sequencing. The relationship between the severity of dental fluorosis and the allele distribution was determined by the Fisher's exact and Kruskal-Wallis tests.

RESULTS

Seventy-one students were included for the sequencing. In the different allelic variations, for the normal genotype AA/TT, the control group presented 75%, for the AG/TC variation, 70.8% in the TF ≤ 4 group, 65% in TF ≥ 5, and 16.7% in TF = 0; with respect to GG/CC variation, 12.5% in TF ≤ 4, 22% in TF ≥ 5, and 8.3% in TF = 0 group (p = 0.000).

CONCLUSION

The ENAM gene showed an association in the population exposed to different concentrations of fluoride.

Effectiveness of a microabrasion technique using 16% HCL with manual application on fluorotic teeth: A series of studies

BACKGROUND

Dental fluorosis is caused by excessive fluoride ingestion during tooth formation. As a consequence, there is a higher porosity on the enamel surface, which causes an opaque look.

AIM

The aim of this study was to identify a dental intervention to improve the smile in patients with tooth fluorosis. Additional aims were to relate the stain size on fluorotic teeth with the effectiveness of stain removal, enamel loss and procedure time using a manual microabrasion technique with 16% hydrochloric acid (HCL).

METHODS

An experimental study was carried out on 84 fluorotic teeth in 57 adolescent patients, 33 females and 24 males, with moderate to severe fluorosis. The means, standard deviations and percentages were analyzed using nonparametric statistics and ArchiCAD 15 software was used for the variables including stain size and effectiveness of stain removal.

RESULTS

The average enamel loss was 234 µm and was significantly related to the procedure time categorized as 1-4 min and 4.01-6 min, resulting in a P > 0.000. The microabrasion technique using 16% HCL was effective in 90.6% of patients and was applied manually on superficial stains in moderate and severe fluorosis. Procedure time was less than 6 min and enamel loss was within the acceptable range.

CONCLUSION

Microabrasion is a first-line treatment; however, the clinician should measure the average enamel loss to ensure that it is within the approximate range of 250 µm in order to avoid restorative treatment.

DNA sequencing reveals AMELX, ODAM and MMP20 variations in dental fluorosis

OBJECTIVE

Dental fluorosis (DF) is a dental development disorder caused by chronic fluoride overconsumption. There are differences in the susceptibility to and severity of DF in studied populations. The objective of the present study was to determine if single-nucleotide variations (SNVs) in the genes Amelogenin (AMELX), Odontogenic Ameloblast Associated (ODAM) and Matrix Metalloproteinase 20 (MMP20) are associated with DF by evaluating the relationship between variations in these genes and the degree of DF severity.

SUBJECTS AND METHODS

Schoolchildren from two regions of Durango State and Mexico City, Mexico, were studied. The DF phenotype was determined using the Thylstrup and Fejerskov (TF) index. DNA was obtained from the buccal mucosa of each participant, and the presence of the variations rs946252 in AMELX, rs1514392 in ODAM and rs1784418 in MMP20 was determined by bidirectional DNA sequencing.

RESULTS

A total of 180 DNA samples from 30 schoolchildren from 2 areas of Durango State were sequenced and analyzed. Differences in the severity of DF were found between the study areas (p = 0.006). SNVs in theMMP20 gene were present in 76.9 % of the participants in the high fluoride concentration and lower DF severity area.

CONCLUSION

AMELX and ODAM variations was not different between the two populations with respect to DF severity; however, the presence of rs1784418 differed between phenotypes with regard to susceptibility to DF. Therefore, MMP20 might be related to the various phenotypes of DF and may serve as a protective marker.

Current concepts in ameloblastoma-targeted therapies in B-raf proto-oncogene serine/threonine kinase V600E mutation: Systematic review

BACKGROUND

Ameloblastomas are common benign epithelial odontogenic neoplasms that present an aggressive and unpredictable behavior that may modify treatment strategies. Different signaling pathways that participate in the progression of these tumors have been identified. B-raf proto-oncogene serine/threonine kinase (BRAF) is a protein involved in the behavior of ameloblastomas, and it is related to many cell mechanisms. BRAF gene mutations have been identified in ameloblastomas, of which the BRAF V600E (valine substituted by glutamic acid at amino acid 600) mutation has been the most common and can be present concomitantly with other mutations that may be involved in its behavior. Targeted therapies have been used as an alternative in the case of resistance or contraindications to conventional treatments.

AIM

To document the presence of BRAF V600E and additional mutations, their behavior, and targeted therapies in these tumors.

METHODS

An electronic literature search was conducted according to PRISMA guidelines in PubMed/MEDLINE, Cochrane, EMBASE, and SpringerLink using the terms “ameloblastomas”, “BRAF V600E”, “additional mutations”, and “targeted therapies”. Ameloblastomas were classified according to WHO guidelines. Inclusion criteria were articles in English, published not more than 10 years ago, and studies with laboratory works related to BRAF V600E. Articles were evaluated by two independent reviewers and retrieved for full-text evaluation. The EBLIP Critical Appraisal Checklist was used to evaluate the quality of the eligible studies. Descriptive statistical analysis was performed.

RESULTS

Two independent reviewers, with a substantial concordance indicated by a kappa coefficient of k = 0.76, evaluated a total of 19 articles that were included in this study. The analysis registered 521 conventional ameloblastomas (AM), 81 unicystic ameloblastomas (UA), 13 ameloblastic carcinomas (AC), three metastatic ameloblastomas (MA), and six peripheral ameloblastomas (PA), of which the histopathological type, anatomic location, laboratory tests, expression of BRAF mutation, and additional mutations were registered. The BRAF V600E mutation was found in 297 AM (57%), 63 UA (77.7%), 3 AC (23%), 1 MA (50%), and 5 PA (83.3%). Follicular type predominated with a total of 116 cases (40%), followed by plexiform type with 63 cases (22.1%). Furthermore, both types presented additional mutations, in which alterations in JAK3 P132T, SMARCB1, PIK3CA, CTNNB1, SMO, and BRAF G606E genes were found. Four case reports were found with targeted therapy to BRAF V600E.

CONCLUSION

The identification of BRAF V600E and additional mutations as an aid in targeted therapies has been a breakthrough in alternative treatments of ameloblastomas where surgical treatments are contraindicated.

Environmental Exposure of Arsenic in Groundwater Associated to Carcinogenic Risk in Underweight Children Exposed to Fluorides

BACKGROUND

The purpose of this study was to determine the concentration of inorganic arsenic (As) in the potable water available to the population to be able to estimate the non-carcinogenic risks for underweight children and the carcinogenic risk for adults exposed to As intake who live in the Mezquital municipality, Durango, Mexico.

METHODS

The As content was quantifed in the water supply sources for human use and its intake was estimated in Mezquital population, southern Durango. With the data obtained, the hazard quotient (HQ) was calculated to determine the non-carcinogenic risk to develop chronic systemic effects in underweight children. The Environmental Protection Agency (EPA) reference health values estimating As exposure risk are from 0.0003 mg/kg/day (non-carcinogenic) to 1.5 mg/kg/day (carcinogenic risk).

RESULTS

The analyzed waters presented as concentrations that varied from 0.3 to 10.2 µg/L, with a mean of 7.35 µg/L (CI 95% 6.27-8.38). The exposure dose was 0.4 to 1.36, and the HQ was 1.90 to 6.48 mg/kg/day, the estimated carcinogenic risk from adults varied from 1.28 to 4.37E^-4, with values of 3.74-4.37E^-4 mg/kg/day in central area.

CONCLUSIONS

The children are at risk to develop chronic systemic effects due to ingestion of As from water.

The association between the prevalence of dental fluorosis and the socio-economic status and area of residence of 12-year-old students in Uruguay

Objective: This study investigates the association between the prevalence and severity of dental fluorosis, the socio-economic status (SES) and area of residence among 12-year-old schoolchildren in Uruguay.Material and methods: The study was descriptive, cross-sectional, explanatory and observational. Subjects considered eligible were born in 1999 and had their parents' or guardian's prior consent. A questionnaire was used to identify SES according to Centro de Investigaciones Económicas Institute on four levels. Dental fluorosis was determined using the Thylstrup-Fejerskov (TF) index.Results: Of the 1544 students examined, 45.0% showed dental fluorosis. A TF index 1-2 was recorded in 29.3% of the subjects, TF 3 in 20.9%, TF 4 in 6.7% and TF 5-9 in 2.1%. In area 1 (the capital Montevideo city), 84.8% of the subjects had dental fluorosis, a value that was significantly higher than in the inland region (area 2, 24.4%) and border departments (area 3, 22.5%) (x² = 27.92, p < .0001). Students from families with a low socio-economic level showed less prevalence of dental fluorosis than those with a high level (x² = 14.58, p = .002).Conclusion: Significant differences exist in the prevalence of dental fluorosis in relation to place of residence and socio-economic level.

Evaluating the changes in molar incisor hypomineralization prevalence: A comparison of two cross-sectional studies in two elementary schools in Mexico City between 2008 and 2017

Background

Little information is available on the trends over time of the prevalence of molar incisor hypomineralization (MIH). This condition may be preventing dental caries decline.

Aim

(a) To compare the prevalence of MIH, in Mexico City schoolchildren, evaluated in 2008 with a group evaluated in 2017, (b) to identify the association of MIH with dental caries, and (c) to assess the mother's perception of her child's oral health status.

Design

Two cross‐sectional studies performed in 2008 and in 2017 were compared. The oral examiner and the selected schools were the same in both surveys.

Results

A total of 549 schoolchildren were evaluated. The prevalence of MIH in the first survey was 20.3%, and 31.9 % in the second survey, (p = .002). Children with MIH were more likely to have dental caries. The odds ratio was 2.24 (p = .036) and 4.18 (p ˂ .001) in the first and second surveys, respectively. Mothers of children with MIH perceived worse oral health status of their children than the mothers whose children did not have MIH (odds ratio = 4.47, p ˂ .001).

Conclusion

The findings portray a clear increase in prevalence of MIH and highlight the need for increased awareness about this condition among dentists and the general population.

E-Cadherin gene expression in oral cancer: Clinical and prospective data

BACKGROUND

Low protein expression of E-cadherin in oral squamous cell carcinoma (OSCC) has been associated with clinical and histopathological traits such as metastases, recurrence, low survival and poor tumor differentiation, and it is considered a high-risk marker of malignancy. However, it is still unknown whether low expression of E-cadherin is also present at the mRNA level in OSCC cases.

OBJECTIVE

The aim of this study was to compare E-cadherin mRNA expression in OSCC patients and controls and to correlate the expression with clinical and prospective characteristics.

MATERIAL AND METHODS

Forty patients and 40 controls were enrolled. E-cadherin mRNA expression was evaluated by quantitative real-time polymerase chain reaction using TaqMan probes.

RESULTS

E-cadherin mRNA expression was significantly decreased in OSCC patients compared to that of controls (p<0.001). Whereas no significant association between clinical parameters and E-cadherin expression levels was observed, we noted lower E-cadherin expression levels in patients with positive lymph node metastasis.

CONCLUSIONS

E-cadherin mRNA expression was markedly diminished in OSCC, in agreement with previous results that examined E-cadherin expression at the protein level. E-cadherin is downregulated in the early clinical stages of OSCC, and its mRNA levels do not change significantly in the advanced stages, suggesting that there is limited usefulness of this parameter for predicting disease progression.

[Alteración del gen AMELX en amelogénesis imperfecta. Una breve revisión]

Amelogenesis imperfecta is a group of developmental disorders of the dental enamel that is mainly associated with mutations in the AMELX gene. Clinically, it presents different phenotypes that affect the structure and function of dental enamel both in primary and secondary dentition. The purpose of this study was to conduct a literature review on the AMELX functions and mutations that are related to amelogenesis imperfecta. A literature search was carried out in two databases: PubMed and Web of Science, using the keywords "AMELX", "amelogenin", "amelogenesis imperfecta" and "AMELX mutation". Forty articles were reviewed, with AMELX being found to be the predominant gene in the development of dental enamel and amelogenesis imperfecta by altering the structure of amelogenin. In the past few years, the characteristics of the amelogenesis imperfecta process have been described with different phenotypes of hypoplastic or hypo-mineralized enamel, and different mutations have been reported, by means of which the gene sequencing and the position of mutations have been determined.

[Alteración del gen AMELX en amelogénesis imperfecta. Una breve revisión]

Amelogenesis imperfecta is a group of developmental disorders of the dental enamel that is mainly associated with mutations in the AMELX gene. Clinically, it presents different phenotypes that affect the structure and function of dental enamel both in primary and secondary dentition. The purpose of this study was to conduct a literature review on the AMELX functions and mutations that are related to amelogenesis imperfecta. A literature search was carried out in two databases: PubMed and Web of Science, using the keywords "AMELX", "amelogenin", "amelogenesis imperfecta" and "AMELX mutation". Forty articles were reviewed, with AMELX being found to be the predominant gene in the development of dental enamel and amelogenesis imperfecta by altering the structure of amelogenin. In the past few years, the characteristics of the amelogenesis imperfecta process have been described with different phenotypes of hypoplastic or hypo-mineralized enamel, and different mutations have been reported, by means of which the gene sequencing and the position of mutations have been determined.

Comparative Study of the Minichromosome Maintenance Proteins Complex (MCM 4/5/6) in Ameloblastoma and Unicystic Ameloblastoma

INTRODUCTION

Solid/conventional ameloblastoma (AM) and unicystic ameloblastoma (UAM) are the most frequent benign epithelial odontogenic tumors located in the maxillary region, and their treatment usually consists of extensive surgical resection. Therefore, it is relevant to study molecular markers to better understand the biological behavior of these tumors. The aim of this study was to describe and compare the expression of proteins related to cellular proliferation: Ki-67 and MCM4-6 complex.

MATERIALS AND METHODS

An immunohistochemistry technique was performed, with antibodies against Ki-67, MCM4, MCM5, and MCM6, in 10 AM and 10 UAM tumors. The results were quantified using label index and analyzed statistically.

RESULTS

AM and UAM had greater expression of MCM6, followed by MCM5, MCM4, and Ki-67 ( P < .05). Immunoexpression of Ki-67 and MCM5 was exclusively nuclear, whereas the expression of MCM4 and MCM6 was nuclear and cytoplasmic.

CONCLUSION

The results suggest that MCM5 is a trustable cell proliferation marker with higher sensitivity compared with Ki-67 and may be useful to predict the biological behavior of AM and UAM. Despite this, further studies are necessary, including a correlation with clinical parameters to confirm these findings.

Molecular Markers of Anticancer Drug Resistance in Head and Neck Squamous Cell Carcinoma: A Literature Review

This manuscript provides an update to the literature on molecules with roles in tumor resistance therapy in head and neck squamous cell carcinoma (HNSCC). Although significant improvements have been made in the treatment for head and neck squamous cell carcinoma, physicians face yet another challenge-that of preserving oral functions, which involves the use of multidisciplinary therapies, such as multiple chemotherapies (CT) and radiotherapy (RT). Designing personalized therapeutic options requires the study of genes involved in drug resistance. This review provides an overview of the molecules that have been linked to resistance to chemotherapy in HNSCC, including the family of ATP-binding cassette transporters (ABCs), nucleotide excision repair/base excision repair (NER/BER) enzymatic complexes (which act on nonspecific DNA lesions generated by gamma and ultraviolet radiation by cross-linking and forming intra/interchain chemical adducts), cisplatin (a chemotherapeutic agent that causes DNA damage and induces apoptosis, which is a paradox because its effectiveness is based on the integrity of the genes involved in apoptotic signaling pathways), and cetuximab, including a discussion of the genes involved in the cell cycle and the proliferation of possible markers that confer resistance to cetuximab.

Exploratory survey of initial image quality in new digital mammography units prior to use in patients in Mexico

In Mexico, previous studies performed to evaluate the image quality in 2D digital mammography facilities show a poor image quality that is not compatible with mammography screening that may modify breast cancer mortality rate. Image quality is lost due to the quality assurance programs are not implemented. We carried out an exploratory survey of thirty-six new (FFDM) units from a single manufacturer installed in several cities of the Mexican Republic with two types of target/filter combination (Mo/Mo and W/Rh). Tests were performed according to NOM-041-SSA1-2011 (Mexico), the regulation indicates that all facilities using digital mammography systems must maintain a QC program equal to the QC program recommended by the manufacturer. However, QC program recommended by the manufacturer meets with FDA and ACR Regulations. Digital mammography units evaluated exceeds quality image standards established by the ACR and FDA, even though, the W/Rh combination achieved a higher performance and reduces the average glandular dose. All mammography units met the quality control standards established by ACR, FDA and Mexican regulations. Then, the objective of this study was to evaluate the initial image quality and compliances with the manufacturer's quality control specifications before use it in patients in new full-field 2D digital mammography (FFDM) units and compares average glandular dose (AGD) with FFDM units using different anode/filter combinations (Mo/Mo and W/Rh).

Expression of proteoglycans in two types of ameloblastoma: novel Immunohistochemical findings

Alterations in cellular and extracellular matrix components play an important role during tumorigenesis; proteoglycans are included among these components. Ameloblastomas are odontogenic tumors distinguished as invasive and infiltrative neoplasms and are divided into different histological types, the most common of which are the unicystic ameloblastoma and the conventional ameloblastoma. The aim of this study was to identify the presence of two proteoglycans, perlecan and biglycan, in different types of ameloblastoma. Using immunohistochemistry, we determined the presence of both proteins in 28 unicystic ameloblastomas and 23 conventional ameloblastomas. We identified the cytoplasmic and nuclear presence of perlecan and the cytoplasmic presence of biglycan in both types of ameloblastoma. The mean values of immunoexpression were higher in the conventional type compared to the unicystic type. Neither the presence of biglycan in ameloblastomas nor the nuclear presence of perlecan in any odontogenic tumor has previously been reported. The differential immunoexpression of perlecan and biglycan in these types of ameloblastomas suggests their participation in the developmental process of these tumors.

Proteoglycans as potential biomarkers in odontogenic tumors

Proteoglycans (PGs) are essential for normal cellular development; however, alterations of their concentrations can promote tumor growth. To date, a limited number of studies report the presence of PGs in odontogenic tumors (OTs); therefore, the main purpose of this work is to gather the information published on the study of PGs. The search reported 26 articles referring to the presence of different PGs in distinct OTs from 1999 to May 2017. PGs seem to play an important role during OTs' development as they are involved in several tumor processes; however, the number of reports on the study of these molecules is low. Thus, more studies are necessary in order to gain a better understanding of the underlying pathophysiology of OTs.

Severity of Oral Mucositis in Children following Chemotherapy and Radiotherapy and Its Implications at a Single Oncology Centre in Durango State, Mexico

BACKGROUND

Mucositis is an adverse effect of chemotherapy (QT) and/or radiotherapy (RT). The purpose of this study was to investigate the occurrence of oral mucositis in children undergoing cancer treatment.

METHODS

Fifty-one children with cancer who had received QT, RT, or both (QT-RT) underwent clinical evaluations; World Health Organization criteria were used to establish the degree and severity of mucositis. The correlations between the clinical data, type of cancer, and therapy were statistically analysed.

RESULTS

Mucositis was present in 88.23% of the patients; 57.78%, 7.78%, and 24.44% received QT, RT, and QT-RT, respectively. Severity scores of 1 and 2 were the most common; scores of 3-4 were observed in patients who received QT-RT or more than 7 treatment cycles. There was a significant association between mucositis, the type of treatment, and the number of cycles received (p < 0.05).

CONCLUSION

It is important to implement therapeutic protocols that help maintain excellent oral health and reduce the risk of oral mucositis. Stomatologists should be consulted to assess patients' oral cavities and provide preventive treatment prior to QT and/or RT administration. It is important to integrate a stomatologist into the oncological working group to focus on preventing and managing oral mucositis.

Differences in E-Cadherin and Syndecan-1 Expression in Different Types of Ameloblastomas

Ameloblastomas are a group of benign, locally aggressive, recurrent tumors characterized by their slow and infiltrative growth. E-Cadherin and syndecan-1 are cell adhesion molecules related to the behavior of various tumors, including ameloblastomas. Ninety-nine ameloblastoma samples were studied; the expression of E-cadherin and syndecan-1 were evaluated by immunohistochemistry. E-Cadherin and epithelial syndecan-1 were more highly expressed in intraluminal/luminal unicystic ameloblastoma than in mural unicystic ameloblastoma and solid/multicystic ameloblastoma, whereas the stromal expression of syndecan-1 was higher in mural unicystic ameloblastoma and solid/multicystic ameloblastoma. Synchronicity was observed between E-cadherin and epithelial syndecan-1; the expression was correlated with intensity in all cases. There was a strong association between expression and tumor size and recurrence. The evaluation of the expression of E-cadherin and syndecan-1 are important for determining the potential aggressiveness of ameloblastoma variants. Future studies are required to understand how the expression of these markers is related to tumor aggressiveness.

Patients with advanced oral squamous cell carcinoma have high levels of soluble E-cadherin in the saliva

BACKGROUND

The objective of this study was to assess the potential clinical value of the concentration of soluble salivary E-cadherin (sE-cadherin) compared with the clinical value of the presence of membranous E-cadherin (mE-cadherin) in oral squamous cell carcinoma tumor tissues.

MATERIAL AND METHODS

Data regarding patient demographics, clinical stage, saliva and tumor tissue samples were collected. The saliva was analyzed for sE-cadherin protein levels and was compared to the mE-cadherin immunohistochemical expression levels in tumor tissues, which were assessed via the HercepTest® method. Patients without cancer were included in the study as a control group for comparisons of the sE-cadherin levels.

RESULTS

sE-cadherin levels in the saliva of patients without cancer were lower than those in patients with cancer, and the difference was statistically significant (p=0.031). Low mE-cadherin expression was statistically significantly associated with lymph node positivity (p=0.015) and advanced clinical stage (p=0.001). The inverse relationship between mE-cadherin and sE-cadherin was significant in terms of lymph node positivity (p=0.014) and advanced clinical stage (p=0.037).

CONCLUSIONS

The results suggest that sE-cadherin levels are significantly increased in patients with oral cancer and that its low expression within the membrane as well as the progression of the disease appear to be inversely associated with levels of sE-cadherin in the saliva.

Impact of Dental Fluorosis, Socioeconomic Status and Self-Perception in Adolescents Exposed to a High Level of Fluoride in Water

Objective: To identify adolescents' self-perception of dental fluorosis from two areas with different socioeconomic levels. Methods: A cross-sectional, descriptive study was conducted with 15-year-old youths by applying a questionnaire designed and validated to assess self-perceptions of dental fluorosis in two areas with different socioeconomic statuses (SESs). Fluorosis was clinically evaluated by applying the Thylstrup and Fejerkov (TF) index on the upper front teeth. Results: A total of 308 adolescents were included in the study. The medium-SES population, which was exposed to 2.5 ppm of fluoride in water, and the low-SES population, which was exposed to 5.1 ppm, presented the following levels of dental fluorosis: TF 2-3 (50%), TF 4-5 (45.6%) and TF 6-7 (4.4%) for medium SES and TF 2-3 (12.3%), TF 4-5 (67.1%) and TF 67 (20.6%) for low SES. A significant association was found between self-perception and dental fluorosis in those with medium and low SESs (p < 0.05). The multiple regression model found differences between TF levels and self-perception, with a 6-7 TF level for concerns about color (OR = 1.6), smile (OR = 1.2) and appearance (OR = 3.36). Conclusions: Self-perceptions of dental fluorosis affect adolescents such that adolescents with a medium SES have more negative perceptions than those with a low SES. Such perceptions increase as the TF index increases.

Orosomucoid-1 Expression in Ameloblastoma Variants

Odontogenic tumors constitute a group of heterogeneous lesions of benign and malignant neoplasms with variable aggressiveness. Ameloblastomas are a group of benign but locally invasive neoplasms that occur in the jaws and are derived from epithelial elements of the tooth-forming apparatus. We previously described orosomucoid-1 protein expression in odontogenic myxomas. However, whether orosomucoid-1 is expressed in other odontogenic tumors remains unknown. Since orosomucoid-1 belongs to a group of acute-phase proteins and has many functions in health and disease, we identified and analyzed orosomucoid-1 expression in ameloblastoma variants and ameloblastic carcinoma using western blot and immunohistochemical techniques. Thirty cases of ameloblastoma were analyzed for orsomucoid-1; five specimens were fresh for western blot study (four benign ameloblastomas and one ameloblastic carcinoma), and 25 cases of benign ameloblastoma for immunohistochemical assays. Orosomucoid-1 was widely expressed in each tumor variant analyzed in this study, and differential orosomucoid-1 expression was observed between benign and malignant tumor. Orosomucoid-1 may play an important role in the behavior of ameloblastomas and influence the biology and development of the variants of this tumor.

Comparison between Manual and Automated Methods for Ki-67 Immunoexpression Quantification in Ameloblastomas

Ameloblastoma is a common and unpredictable odontogenic tumor with high relapse rates. Several studies assessing the proliferative capacity of these neoplasms have been published, mainly using the protein Ki-67. Cell counts must be completed to determine the cell proliferation rate. Multiple methods have been developed for this purpose. The most widely used method is the labeling index, which has undergone changes over time to better facilitate cell counting. Here, we compared manual cell counting methods with automated cell counting (ImmunoRatio) to determine the relative effectiveness of these methods. The results suggest that ImmunoRatio, a free software tool, may be highly advantageous and provide results similar to manual cell counting methods when used with the appropriate calibration. However, ImmunoRatio has flaws that may affect the labeling index results. Therefore, this automated cell counting method must be supplemented with manual cell counting methods.

Fluoride Exposure Effects and Dental Fluorosis in Children in Mexico City

BACKGROUND The objective of the present study was to determine the prevalence and severity of dental fluorosis and to evaluate exposure to fluoridated products in students in the southwest part of the Federal District (Mexico City). MATERIAL AND METHODS Students between 10 and 12 years of age who were born and raised in the study zone were evaluated. The level of dental fluorosis was determined using the modified Dean index (DI) using criteria recommended by the World Health Organization (WHO). A bivariate analysis was performed with the χ2 test, and odds ratios (OR) and 95% confidence intervals (CI) are presented. Logistic regression was performed to evaluate the association between dental fluorosis and the independent variables. RESULTS A total of 239 students were evaluated. Their mean age was 11±0.82 years, and there were 122 (51%) males. Overall, dental fluorosis was found in 59% of participants; 29.3% had very mild fluorosis, 20.9% had mild fluorosis, 6.7% had moderate fluorosis, and 2.1% had severe fluorosis. The mean fluorosis score was 0.887±0.956. In the final logistic regression model, dental fluorosis was significantly associated with frequency of brushing (OR: 0.444; 95% CI: 0.297-0.666) and with the absence of parental supervision (OR: 0.636; 95% CI: 0.525-0.771). CONCLUSIONS The association found with frequency of brushing and lack of parental supervision may be contributing to the prevalence and severity of dental fluorosis.

[Dental caries experience and its relation to oral hygiene in Mexican children]

INTRODUCTION

Dental caries is public health problem in Mexico and there are few studies on preschool children.

OBJECTIVE

The aim of this study was to determine the caries experience in preschool children and its relation to oral hygiene in an underserved area of ​​the state of Mexico.

MATERIAL AND METHODS

A cross-sectional, descriptive, observational and analytical study in children aged four and five years of age enrolled in children´s centers. The sociodemographic variables were obtained through a questionnaire. Clinical evaluation of each of the infants was performed using the CPOD index for primary teeth caries , the criteria of the World Health Organization, and the significant caries index was calculated and oral hygiene was assessed using the criteria of the O'Leary index. Calibration was kappa>0.86 for indexes.

RESULTS

The study population consisted of children of both genders: 69.5% had caries experience, and the index of decayed, missing, and filled teeth (DMFT) was 3.52±3.7 (d=3.37±3.5; m=0; f=0.11±0.51). The significant caries index was 8.95±0.39 (d=8.68±0.41; f=0.26±0.13). In total, 98.2% of children with caries experience had poor oral hygiene (DMFT: 4.91: 95% CI: 3.99-5.84), whereas in children with good hygiene it was 0.17 (95% CI: -0.18-0.51); existing association between caries experience and oral hygiene RM 913 (95% CI: 864-962; p<0.01).

CONCLUSIONS

The caries experience of preschool children was high and was associated with poor oral hygiene affecting their dentition and usually is associated with caries in permanent dentition associated to social deprivation. Preventive programs are recommended from the first stage of life.

Differential expression of glypican-1 in ameloblastoma variants

Although benign, ameloblastomas are locally invasive and destructive tumors of the jawbones. The glypicans comprise a family of glycosylphosphatidylinositol-anchored proteoglycans that, by virtue of their cell-surface localization and heparin sulfate chain composition, might regulate the response of cells to numerous heparin-binding growth factors, cell adhesion molecules, and extracellular matrix components. The expression of glypican-1 is differentially altered among different types of malignancies, suggesting a possible role in the tumorigenesis and biological behavior of these neoplasms. The aim of this study was to determine the expression of glypican-1 and then hypothesize the possible role that this protein may play in the biological behavior of ameloblastomas. We assessed the presence of glypican-1 by immunohistochemical staining analyses in a series of 80 cases of different types of ameloblastomas. Desmoplastic ameloblastomas exhibited the highest expression of glypican-1 (100%), followed by the peripheral (66%), solid/multicystic (51.2%), and unicystic (47.2%) types, showing statistically significant differences among them (P<0.001). Differences detected in glypican-1 expression among different subtypes of ameloblastomas, could be suggesting a possible association with their different biological behavior.

Immunohistochemical expression of Survivin and its relationship with cell apoptosis and proliferation in ameloblastomas

Ameloblastoma behavior is related to the potential of tumor cells to inhibit apoptosis and to initiate a proliferative phase. This study was performed to compare the immunoexpression of Survivin with Bcl-2, Bax, and Ki-67 and to associate them with the histopathological type of each variant of ameloblastoma.

MATERIAL AND METHODS

Using the World Health Organization (WHO) criteria for ameloblastoma, 110 cases were selected. The cases were classified as solid/multicystic and unicystic ameloblastomas. Cellular counts of cytoplasmic immunoexpression were assessed for cytoplasmic Survivin, Bcl-2, and Bax, while the nuclear immunoexpression of Survivin and Ki-67 was assessed using label index.

RESULTS

Cytoplasmic Survivin and Bcl-2 showed higher percentages of immunoexpression in solid multicystic ameloblastomas compared to unicystic ameloblastomas (P < 0.05). Bax, Ki-67, and nuclear Survivin were expressed in higher percentages in unicystic ameloblastomas.

CONCLUSIONS

Cytoplasmic Survivin and Bcl-2 immunoexpression levels were elevated in relation to Bax immunoexpression, suggesting aggressive ameloblastoma behavior, while Ki-67 and nuclear Survivin immunoexpression may be associated with the type of tumor morphology that influences cellular counts or with the greater capacity for cellular proliferation and tumor growth.