Decalcification-free technique on the analysis of dental pulp tissue: histological and immunohistochemical analysis.

BACKGROUND: Histological techniques are essential for the microscopic study and investigation of the human dental pulp. The aim of this study was to evaluate the impact of decalcification-free technique by examining dental pulp morphology by histological staining with haematoxylin and eosin and immunohistochemistry. MATERIALS AND METHODS: The sample consisted of 30 healthy third molars extracted for orthodontic indication, the pulp tissue was obtained by removing the mineralized tissues, separating the enamel and dentine and by marking with a flexible diamond disc on the coronal surface and longitudinal axis of the root. These guides made it possible to separate the fragments and obtain the pulp tissue for fixation and staining with H&E and subsequent immunohistochemistry with CD34 and S-100 antibodies. RESULTS: The technique showed preservation of pulp morphology with adequate preservation of microscopic structures. No alterations in tissue viability were observed. The staining allowed an accurate assessment of vascular and nervous components by means of CD34 and S-100 markers, respectively. CONCLUSIONS: This technique allows preservation of pulp tissue, maintaining viable tissue for histological analysis and immunohistochemistry tests, as well as reducing sample processing time.

Use of Electropolishing in Orthodontic Appliances: An Option to Reduce the Risk of Metal Hypersensitivity.

Electropolishing is a common treatment in the industry; however, how it behaves in the mouth and what benefits it can bring over metal dental attachments have not yet been established. Thus, the aim of this study was to determine the levels of corrosion, the released metal ions, and the changes in structural composition in metallic orthodontic appliances following electropolishing treatment. This study included 56 orthodontic brackets and 28 archwires. The samples were subjected to a pH cycle to simulate an oral environment. Using UV-Vis spectrophotometry, the release of metallic particles was evaluated, and using scanning electron microscopy, the structural and composition changes were evaluated. Groups were compared using Student's t-tests with a value of p ≤ 0.05. The cyclical pH solutions showed variations between groups and days (1, 3, 5, 7 and 15), reaching the highest acidification in the self-ligating brackets; the absorbance between solutions did not differ significantly. As seen from the SEM results, the experimental group showed minor irregularities compared with the control groups. The experimental brackets decreased in iron and increased in chromium after electropolishing, while for the NiTi archwires, they decreased in nickel. Therefore, electropolishing treatments in metallic orthodontic attachments improve their surface structure and corrosion resistance could reduce the risk of metal hypersensitivity, mainly from nickel.

Clinical and socio-demographic factors associated with dental extractions in a clinical sample.

The objective of the present study was to identify the reasons for dental extractions in patients seeking dental care in a university dental clinic in Mexico. This is a cross-sectional study that assessed 284 consecutive patients at the School of Dentistry, Autonomous University of the State of Mexico between August 2017 and November 2018. In total, 505 extractions were performed. The dependent variable was the reason for extraction: 0) dental caries and ensuing sequels (reference category); 1) periodontal disease and ensuing sequels; and 2) other reasons. Sociodemographic, socioeconomic, and clinical variables were included as independent variables. The analysis was done with multinomial logistic regression (Stata 14.0). Out of all extractions, 63.6% (n=321) were due to dental caries and ensuing sequels; 22.0% (n=111) were due to periodontal disease and ensuing sequels; 5.3% (n=27) endodontic failure; 5.1% (n=26) prosthetic indications; 1.6% (n=8) orthodontic indications; and the rest (2.4%) were due to other reasons. In the multivariate model extractions due to periodontal disease vs dental caries were associated with occasionally smoking tobacco (Odds Ratio, OR=3.90) or daily tobacco use (OR=3.19); the tooth to be extracted having been previously restored (OR=2.35); extracted anterior as opposed to posterior teeth (OR =2.63); and patients with multiple extractions (OR=2.68). In the case of extractions due to "other reasons", no variable was significant. Dental caries and periodontal disease were the main reasons for dental extraction in this sample. Several variables, mostly clinical, were associated with extractions for periodontal reasons.

Healing of Recurrent Aphthous Stomatitis by Non-Thermal Plasma: Pilot Study.

Recurrent aphthous stomatitis (RAS) is a common disease in the oral cavity characterized by recurrent ulcers (RU). Usually, these cause acute pain without definitive treatment. The present study determines the efficacy of non-thermal plasma (NTP) for treating RU. NTP is applied to the patient's RU using a radiofrequency generator connected to a point reactor. The power density applied to the ulcer is 0.50 W/cm2, less than 4 W/cm2, which is the maximum value without biological risk. Each patient received two treatments of three minutes each and spaced 60 min apart at a distance of 5 mm from the RU. From a sample of 30 ulcers in patients treated for RU with an average age of 37 years, they stated that the pain decreased considerably and without the need for ingestion of analgesics and antibiotics. Regeneration took place in an average of three days. The NTP proved to be an excellent therapeutic alternative for the treatment of RU since it has a rapid effect of reducing pain and inflammation, as well as adequate tissue regeneration.

Use of liquid-based cytology samples reveals genomic instability and cell death in patients undergoing orthodontic treatment.

PURPOSE: To examine the use of liquid-based exfoliative cytology to determine the presence of genomic instability and cell death in the oral mucosa of patients with orthodontic appliances. METHODS: Fifty-four oral mucosa samples were collected from 18 patients and divided into three stages: T0, before fixation of orthodontic appliances; T1, 25 days after appliance fixation; T2, 90 days after appliance fixation. All samples were Papanicolaou-stained and observed by microscopy (1,000 cells/sample) to ascertain the frequency of micronucleated cells (MN) and nuclear abnormalities (nuclear buds (NB), binucleated (BN), condensed chromatin (CC), karyorrhexis (KR), and karyolysis (KL)). Differences were analyzed statistically using the Mann-Whitney, Wilcoxon, Kruskal-Wallis and chi-squared tests. RESULTS: After placement of orthodontic appliances, significant differences were observed for genomic instability biomarkers (MN and NB) and cell death (CC, KR and KL) (P < 0.05). Female patients and older patients exhibited a higher frequency of MN. CONCLUSION: Liquid-based cytology has revealed that orthodontic appliances induce genomic instability and cell death in epithelial tissue of the oral mucosa, facilitating sample preservation and yielding more than one preparation per sample. Future studies should investigate whether such cell damage can be reversed through cell repair or whether cell alterations evolve and lead to disease.

Clinical and socio-demographic factors associated with dental extractions in a clinical sample

Abstract The objective of the present study was to identify the reasons for dental extractions in patients seeking dental care in a university dental clinic in Mexico. This is a cross-sectional study that assessed 284 consecutive patients at the School of Dentistry, Autonomous University of the State of Mexico between August 2017 and November 2018. In total, 505 extractions were performed. The dependent variable was the reason for extraction: 0) dental caries and ensuing sequels (reference category); 1) periodontal disease and ensuing sequels; and 2) other reasons. Sociodemographic, socioeconomic, and clinical variables were included as independent variables. The analysis was done with multinomial logistic regression (Stata 14.0). Out of all extractions, 63.6% (n=321) were due to dental caries and ensuing sequels; 22.0% (n=111) were due to periodontal disease and ensuing sequels; 5.3% (n=27) endodontic failure; 5.1% (n=26) prosthetic indications; 1.6% (n=8) orthodontic indications; and the rest (2.4%) were due to other reasons. In the multivariate model extractions due to periodontal disease vs dental caries were associated with occasionally smoking tobacco (Odds Ratio, OR=3.90) or daily tobacco use (OR=3.19); the tooth to be extracted having been previously restored (OR=2.35); extracted anterior as opposed to posterior teeth (OR =2.63); and patients with multiple extractions (OR=2.68). In the case of extractions due to "other reasons", no variable was significant. Dental caries and periodontal disease were the main reasons for dental extraction in this sample. Several variables, mostly clinical, were associated with extractions for periodontal reasons.

Resumo O objetivo do presente estudo foi identificar os motivos das extrações dentárias em pacientes que procuram atendimento odontológico em uma clínica odontológica universitária no México. Este é um estudo transversal que avaliou 284 pacientes consecutivos na Faculdade de Odontologia da Universidad Autónoma del Estado de México entre agosto de 2017 e novembro de 2018. No total, foram realizadas 505 extrações. A variável dependente foi o motivo da extração: 0) cárie dentária e sequelas subsequentes (categoria de referência); 1) doença periodontal e sequelas subsequentes; e 2) outros motivos. Variáveis sociodemográficas, socioeconômicas e clínicas foram incluídas como variáveis independentes. A análise foi feita com regressão logística multinomial (Stata 14.0). De todas as extrações, 63,6% (n=321) foram devidas a cárie dentária e sequelas subsequentes; 22,0% (n=111) foram devidas a doença periodontal e sequelas subsequentes; 5,3% (n=27) a insucesso endodôntico; 5,1% (n=26) a indicações protéticas; 1,6% (n=8) a indicações ortodônticas; e o restante (2,4%) foi devido a outros motivos. No modelo multivariado, as extrações por doença periodontal vs. cárie dentária foram associadas ao tabagismo ocasional (Odds Ratio, OR=3,90) ou ao uso diário de tabaco (OR=3,19); ao fato de o dente a ser extraído ter sido restaurado anteriormente (OR=2,35); à extração de dentes anteriores em vez de posteriores (OR=2,63); e a pacientes com extrações múltiplas (OR=2,68). No caso de extrações devido a "outros motivos", nenhuma variável foi significativa. A cárie dentária e a doença periodontal foram os principais motivos de extração dentária nessa amostra. Diversas variáveis, principalmente clínicas, foram associadas às extrações por motivos periodontais.

Enhancement of fluoride release in glass ionomer cements modified with titanium dioxide nanoparticles.

BACKGROUND: Several efforts have been made to improve the glass ionomer cements (GICs) properties with nanotechnology. Fluoride release in once of most beneficial properties of GICs. The purpose of this study was to evaluate the fluoride release, recharge, and cytotoxicity in GICs reinforced with titanium dioxide nanoparticles (TiO2N). OBJECTIVE: Evaluate the fluoride release, recharge, and cytotoxicity in GICs reinforced with TiO2N. METHODS: Four GICs, FUJI IX EXTRA (G1c), KETAC MOLAR (G2c), IONOFILL MOLAR (G3c), and FUJI IX (G4c) were combined with TiO2N (G1e, G2e, G3e, and G4e) and divided into blocks of 5-mm width and 1-mm thickness 10 each. A total of 80 samples were arranged as follows: GICs alone as negative control (n = 40) and GICs + TiO2N as experimental groups (n = 40). The fluoride release was determined for periods of 1, 2, 6, 10, 31, 90, 180, 240, and 300 days. On days 30 and 179, samples were recharged by submerging in 1 mL of 20,000 ppm sodium fluoride gel. Cytotoxic activity was carried out with gingival fibroblasts, using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide cell viability assay. RESULTS: The experimental groups obtained the highest and more constant fluoride released when compared to control groups. After the first recharge, experimental groups (G1e, G3e, and G4e) showed statistically significant results (P = .001, 0.010, and 0.001 respectively) enhancing their recharge ability regarding control groups. The second recharge showed better results in G1e concerning the rest of the groups. No cytotoxic activity was observed in all experimental groups, although significant differences were observed in G3e and G4e regarding control group. CONCLUSION: The incorporation of TiO2N enhance the fluoride release in glass ionomers with a noncytotoxic effect on human gingival fibroblasts.

Traumatic dental injuries in 6 to 12 years old schoolchildren: a multicenter cross-sectional study in Mexico.

The aim of this study was to determine the prevalence of dental trauma in schoolchildren 6 to 12 years of age and associated clinical, sociodemographic, and socioeconomic variables. A cross-sectional study was conducted in 477 children from public elementary schools in four locations in Mexico. The dependent variable was dental trauma, which was dichotomized in 0 = without dental trauma and 1 = with dental trauma. For the statistical analysis, a multivariate binary logistic regression model was generated in Stata. Average age was 9.06±1.94 years and 51.1% were girls. The prevalence of dental trauma was 18.2%. Falls, automobile accidents and sports had the highest number of instances (p < 0.01). In the multivariate model, it was observed that the risk of dental trauma increased with age (OR = 1.28) and among boys (OR = 1.45). Schoolchildren with decreased overjet (OR = 0.38) had lower dental trauma. Father's age (OR = 1.03) and educational level (OR = 1.78) were associated with dental trauma. Schoolchildren without health insurance (OR = 0.62) presented dental trauma less often. This study provided important information regarding the association of different sociodemographic, socioeconomic and clinical variables with dental trauma in Mexican schoolchildren. Identifying factors associated with dental trauma may support health promotion opportunities to ameliorate the prevalence of dental trauma.

Mechanical Properties and Antibacterial Effect on Mono-Strain of Streptococcus mutans of Orthodontic Cements Reinforced with Chlorhexidine-Modified Nanotubes.

Recently, several studies have introduced nanotechnology into the area of dental materials with the aim of improving their properties. The objective of this study is to determine the antibacterial and mechanical properties of type I glass ionomers reinforced with halloysite nanotubes modified with 2% chlorhexidine at concentrations of 5% and 10% relative to the total weight of the powder used to construct each sample. Regarding antibacterial effect, 200 samples were established and distributed into four experimental groups and six control groups (4 +ve and 2 -ve), with 20 samples each. The mechanical properties were evaluated in 270 samples, assessing microhardness (30 samples), compressive strength (120 samples), and setting time (120 samples). The groups were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy, and the antibacterial activity of the ionomers was evaluated on Streptococcus mutans for 24 h. The control and positive control groups showed no antibacterial effect, while the experimental group with 5% concentration showed a zone of growth inhibition between 11.35 mm and 11.45 mm, and the group with 10% concentration showed a zone of growth inhibition between 12.50 mm and 13.20 mm. Statistical differences were observed between the experimental groups with 5% and 10% nanotubes. Regarding the mechanical properties, microhardness, and setting time, no statistical difference was found when compared with control groups, while compressive strength showed higher significant values, with ionomers modified with 10% concentration of nanotubes resulting in better compressive strength values. The incorporation of nanotubes at concentrations of 5% and 10% effectively inhibited the presence of S. mutans, particularly when the dose-response relationship was taken into account, with the advantage of maintaining and improving their mechanical properties.

Antimicrobial Activity of Biogenic Silver Nanoparticles from Syzygium aromaticum against the Five Most Common Microorganisms in the Oral Cavity.

Syzygium aromaticum (clove) has been used as a dental analgesic, an anesthetic, and a bioreducing and capping agent in the formation of metallic nanoparticles. The main objective of this study was to evaluate the antimicrobial effect in oral microorganisms of biogenic silver nanoparticles (AgNPs) formed with aqueous extract of clove through an ecofriendly method "green synthesis". The obtained AgNPs were characterized by UV-Vis (ultraviolet-visible spectroscopy), SEM-EDS (scanning electron microscopy-energy dispersive X-ray spectroscopy), TEM (transmission electron microscopy), and ζ potential, while its antimicrobial effect was corroborated against oral Gram-positive and Gram-negative microorganisms, as well as yeast that is commonly present in the oral cavity. The AgNPs showed absorption at 400-500 nm in the UV-Vis spectrum, had an average size of 4-16 nm as observed by the high-resolution transmission electron microscopy (HR-TEM), and were of a crystalline nature and quasi-spherical form. The antimicrobial susceptibility test showed inhibition zones of 2-4 mm in diameter. Our results suggest that AgNPs synthesized with clove can be used as effective growth inhibitors in several oral microorganisms.

Evaluation of tooth demineralization using laser-fluorescence in dental school patients undergoing orthodontic treatment: A clinical study.

BACKGROUND: Adverse effects can occur during orthodontic treatment. OBJECTIVE: To evaluate the relationship between prevalence and severity of enamel demineralization using a laser-fluorescence device, with length of orthodontic treatment time. METHOD: A cross-sectional study was conducted in 60 patients in a university orthodontic clinic. A clinical examination to establish demineralization at four sites on each tooth (premolar to premolar) was performed using the DIAGNOdent pen. The dependent variable was enamel demineralization, from which the prevalence (at least one affected site), extension (percentage of affected teeth) and adjusted average (average of the mean DIAGNOdent values per tooth) were calculated. The length of time for orthodontic treatment was determined in months. Various sociodemographic and clinical covariates were included. RESULTS: Average number of months under orthodontic treatment was 26.37 ± 24.81 months. Prevalence of enamel demineralization was 80.0%, its extension was 21.9% ± 17.2 and adjusted average of DIAGNOdent values was 6.09 ± 1.75. By quadrant, the teeth most affected were 14 (34.4%), 24 (25.0%), 31 (30.2%) and 44 (33.3%). No significant relationship (p> 0.05) was observed between enamel demineralization and length of time under orthodontic treatment. CONCLUSIONS: A high prevalence of dental demineralization was observed. In this sample, no relationship was observed between months under treatment and dental demineralization, or with other variables included in the study.

Spongiotic hyperplasia of the oral mucosa: case series and immunohistochemical analysis.

The localized juvenile spongiotic gingival hyperplasia (LJSGH) mainly affects the maxillary vestibular attached gingiva of juvenile patients, without sex predilection. Similar lesions involving extragingival sites have not been reported to date. Here, we report 2 cases of extragingival soft tissue lesions with similar clinicopathological features to those reported in LJSGH and 12 cases of intraoral reactive soft tissue lesions microscopically showing LJSGH-like focal areas. The 2 cases were adult patients, affecting the maxillary alveolar ridge (55-year-old female) and hard palate (78-year-old male), which were diagnosed as "spongiotic hyperplasia of the oral mucosa." The 12 intraoral reactive soft tissue lesions (6 men and 6 women; mean age, 49.5 years) were diagnosed as inflammatory fibrous hyperplasia (n = 6), peripheral ossifying fibroma (n = 3), and pyogenic granuloma (n = 3), each of them presenting LJSGH-like focal areas. By immunohistochemistry, the spongiotic hyperplasia areas showed positivity for CK19, CK14, CK34ßE12, and CAM5.2 (weak/focal), while CK4 was negative. Considering the anatomical locations (extragingival) of these 2 cases, the term "spongiotic hyperplasia of the oral mucosa" is suggested. Moreover, LJSGH-like focal areas can be detected when microscopically assessing common intraoral reactive soft tissue lesions.

Traumatic dental injuries in 6 to 12 years old schoolchildren: a multicenter cross-sectional study in Mexico

Abstract The aim of this study was to determine the prevalence of dental trauma in schoolchildren 6 to 12 years of age and associated clinical, sociodemographic, and socioeconomic variables. A cross-sectional study was conducted in 477 children from public elementary schools in four locations in Mexico. The dependent variable was dental trauma, which was dichotomized in 0 = without dental trauma and 1 = with dental trauma. For the statistical analysis, a multivariate binary logistic regression model was generated in Stata. Average age was 9.06±1.94 years and 51.1% were girls. The prevalence of dental trauma was 18.2%. Falls, automobile accidents and sports had the highest number of instances (p < 0.01). In the multivariate model, it was observed that the risk of dental trauma increased with age (OR = 1.28) and among boys (OR = 1.45). Schoolchildren with decreased overjet (OR = 0.38) had lower dental trauma. Father's age (OR = 1.03) and educational level (OR = 1.78) were associated with dental trauma. Schoolchildren without health insurance (OR = 0.62) presented dental trauma less often. This study provided important information regarding the association of different sociodemographic, socioeconomic and clinical variables with dental trauma in Mexican schoolchildren. Identifying factors associated with dental trauma may support health promotion opportunities to ameliorate the prevalence of dental trauma.

Effect of Human Development Index and other socioeconomic factors on mortality-to-incidence ratio of lips and oral cavity cancer in Mexican states: an ecological study.

OBJECTIVES: To assess the association between the Human Development Index (HDI) and covariates on the mortality-to-incidence ratio (MIR) of lips and oral cavity cancer (LOCC) in Mexico. DESIGN: Ecological study. SETTING: Data from 32 Mexican states for year 2019. PARTICIPANTS: Data set of male and female populations from Mexico. EXPOSURES: Socioeconomic conditions based on HDI and covariates related to healthcare system capacity (total health spending per capita, school dropout and ratio of medical personnel in direct contact with patients). PRIMARY AND SECONDARY OUTCOME MEASURES: MIR of LOCC by state and sex was calculated from the Global Burden of Disease Study website for year 2019. Data for calculating HDI 2019 by state and covariates were obtained from the National Institute of Statistics and Geography. A multiple regression model was constructed to measure the effects of HDI and covariates on LOCC-MIR. RESULTS: Among the states with the highest HDI (>0.780), Colima had the highest aged-standardised rates per 100.000 in men for incidence (5.026) and mortality (3.118). The greatest burden of the disease was found on men, with the highest Men:Women MIR in Colima (3.10) and Baja California Sur (2.73). The highest MIR (>0.65) was found among the states with the lowest HDI (Oaxaca and Chiapas). For each unit of increase of the HDI there was a decrease in the LOCC- MIR of -0.778, controlling for the covariates. The most suitable regression model explained the 57% (F (p): 0.000) of the variance. CONCLUSIONS: Men were most affected by LOCC in Mexican states. The highest MIRs of LOCC were found in the states with the highest HDI. But a worse prognosis of the disease, expressed as a higher MIR, is expected in contexts with lower HDI in the country, even with lower MIRs.

Evaluation of the release of nickel and titanium under orthodontic treatment.

The metal alloys used in dentistry are made mainly of nickel (Ni), titanium (Ti), and other elements such as molybdenum (Mo), zirconium (Zr), iron (Fe), tin (Sn), chrome (Cr), carbon (C), copper (Cu) and niobium (Nb) which can release metal ions in unstable environments. The aim of this work was determine the salivary pH before and during orthodontic treatment; evaluate the release of metal ions, mainly Ni and Ti, in urine and saliva using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES); and evaluate the corrosion using Scanning Electronic Microscopy (SEM). In this study, we selected 35 individuals under orthodontic treatment, from whom saliva and urine samples were collected in 3 stages: (a) basal, (b) at 3 and (c) 6 months after the placement of the fixed appliances. SEM analyzed the Ni-Ti (0.016″) and stainless steel (SS) (0.016 × 0.022″) archs after 1 month of being in contact with the oral cavity. Statistical analysis was performed with Stata using the ANOVA model of repeated measures with a p < 0.05. A statistically significant difference in the concentration of Ni in saliva were found between 3 and 6 months of intervention and Ti in urine was found 3 and 6 months.

Comparison of Fluoride Release in Conventional Glass-Ionomer Cements with a New Mechanical Mixing Cement.

PURPOSE: The aim of this paper was to compare three conventional hand mixing glass-ionomer cements (GICs) and a new mechanical mixing glass-ionomer cement. MATERIALS AND METHODS: Samples were measured on days 1, 2, 6, 10, 31, 90 and 180. After 32 and 181 days of monitoring, the samples were recharged by using 1 ml of 2% sodium fluoride gel. RESULTS: The fluoride release started in high concentration during the first day for all GICs, with a value for GIII of 32.6 ppm. From the 2nd day, a slow, steady decline, with the exception of GII, which showed a marked decline to a value of 3.2 ppm. Analysis of variance (ANOVA) test showed statistically significant differences between the amounts of fluoride of the four materials in the first 24 h. Student t test was used to compare the fluoride release between the first and second recharge in each one of the study groups. Statistically significant differences were found when we compared the fluoride release in groups I (t = -16.95, p = 0.000) and IV (t = -2.644, p = 0.26). CONCLUSIONS: A mechanical mixing was the material with the more constant fluoride release and after recharge showed the highest fluoride release which make it an important benefit for clinicians.