SYNTHESIS, CHARACTERIZATION, ANTIMICROBIAL ACTIVITY OF COPPER FERRITE NANOPARTICLES AND THEIR INCORPORATION IN GLASS IONOMER CEMENT. Pure cubic copper ferrite (c-CuFe2O4), cerium-doped cubic copper ferrite (c-CuCeFe2O4) and pure tetragonal copper ferrite (t-CuFe2O4) nanoparticles were synthesized from the proteic sol-gel method, and characterized by X-ray diffraction, Rietveld method, FT-IR spectroscopy, and field emission scanning electron microscope. The antibacterial activity of the particles was tested in vitro against pathogenic Gram-positive, Gram-negative bacteria. Thus, it has been observed that the nanoparticles are capable of inhibiting the growth of such microorganisms. The nanoparticles were incorporated into glass ionomer cement, followed by Vickers microhardness evaluation. It is concluded that the cubic copper ferrite showed the best antimicrobial result, being the most suitable for market studies (industrial and biomedical). SYNTHESIS CHARACTERIZATION CEMENT cCuFe2O4, cCuFe2O4 cCuFeO c CuFe2O4 , CuFe O (c-CuFe2O4) ceriumdoped cerium doped cCuCeFe2O4 cCuCeFeO CuCeFe2O4 CuCeFe (c-CuCeFe2O4 tCuFe2O4 tCuFeO t (t-CuFe2O4 solgel sol gel method Xray X ray diffraction FTIR FT IR spectroscopy microscope Grampositive, Grampositive Gram positive, positive Gram-positive Gramnegative negative bacteria Thus microorganisms cement evaluation result industrial biomedical. biomedical . biomedical) cCuFe cCuFe2O CuFeO CuFe2O (c-CuFe2O4 cCuCeFe cCuCeFe2O CuCeFeO CuCeFe2O (c-CuCeFe2O tCuFe tCuFe2O (t-CuFe2O (c-CuFe2O

ABSTRACT Objective: To assess the fluoride concentration of bottled waters from municipalities in northeastern Brazil. Material and Methods: Bottled mineral waters were purchased in two periods at different commercial places of four large municipalities (João Pessoa, Campina Grande, Patos, and Cajazeiras) in the Paraíba state. The municipalities selected to present the following annual average temperature: João Pessoa 26.5 °C, Campina Grande 23.3 °C, Patos and Cajazeiras 27.5 °C. Fluoride concentration was determined using a combined ion-specific electrode. Readings (in mV) were conducted in triplicates for each standard solution and converted into fluoride concentration (mg F/L) using the Excel® software. Results: A total of 72 samples from six brands of bottled water were analyzed. The fluoride concentrations of all samples were low (0.11-0.21mg/L) but higher than those reported on the label and varied among different batches of the same brand. Conclusion: The fluoride levels in bottled water vary among brands, and these actual values are not stated in the labels. Objective Brazil Methods state temperature 265 26 5 26. C °C 233 23 3 23. 275 27 27. ionspecific ion specific electrode mV mg F/L FL F L Excel software Results 7 analyzed 0.110.21mg/L 011021mgL mgL 0.11 0.21mg/L 0 11 21mg (0.11-0.21mg/L brand Conclusion labels 2 110 011 0.1 021mgL 1 01 0.

Abstract This study analyzed the relationships between the concentration of natural fluoride in public water supply and meteorological and hydrographic factors in a northeastern region of Brazil. This was a descriptive, analytical, ecological, longitudinal, and field study conducted by collecting water in 23 municipalities (2019 to 2020) of four macroregions of Paraíba (Brazil): coast (1), borborema (2), agreste (3), and outback (4). Four collection sites were selected per municipality: two near and two distant from the water treatment plant. Fluoride concentration was determined using a combined ion-specific electrode and classified according to the Collaborating Center of the Ministry of Health in Oral Health Surveillance. Meteorological, hydrographic, and population characteristics were also collected. All analyzed samples showed natural fluoride; macroregions 2 and 4 showed the highest mean fluoride concentration, macroregion 4 presented the highest mean temperature, and all macroregions showed a similar pattern of precipitation. The mean fluoride concentration of the four macroregions was below the appropriate value to prevent caries. An increase in precipitation would decrease the fluoride concentration in water. In conclusion, the concentration of natural fluoride varied according to meteorological and hydrographic factors. The concentration in surface waters increased during periods of low precipitation. Therefore, this study provided important information to support implementation of community water fluoridation in this region. Brazil descriptive analytical ecological longitudinal 2019 (201 2020 (Brazil) 1, 1 , (1) 2, (2) 3, 3 (3) 4. . (4) municipality plant ionspecific ion specific Surveillance Meteorological collected temperature caries conclusion Therefore 201 (20 202 (Brazil (1 (2 (3 (4 20 (

Abstract: Purpose: to evaluate the effect of dentifrice pH and fluoride concentration ([F]) on fluoride uptake on the biofilm and nails of children from a non-fluoridated area. Methods: two hundred and twenty-eight two- to four-year-old children were randomly allocated into 3 groups according to the type of dentifrice: G1: 1100 μg F/g, pH 4.5 (n = 76); G2: 750 μg F/g, pH 4.5 (n = 74); and G3: 1100 μg F/g, pH 7.0 (n = 78). Nails were collected at 4, 8, and 12 months after starting dentifrice use and biofilm was collected 5 and 60 minutes after toothbrushing. The concentrations of F in nails and biofilm were analyzed by HMDS facilitated diffusion. Data were analyzed by Kruskal-Wallis/Mann-Whitney's test and the comparison between biofilm collection times was done using Wilcoxon test (p £ 0.05). Results: a significant reduction of [F] in biofilm was observed 60 minutes after toothbrushing, regardless of the dentifrice used. However, 5 minutes after toothbrushing, G1 had a significantly higher [F] compared to G2 and G3, and 60 minutes after toothbrushing, [F] was significantly higher for G1 and G2 compared to G3. G1 and G3 had significantly higher [F] in the nails compared to G2. Conclusion: a lower dentifrice concentration is a relevant factor for the reduction of excessive fluoride intake. The use of a low-F acidified dentifrice combines the reduction of fluoride uptake with caries prevention by leading to greater incorporation of F into the biofilm over time.

RESUMO O objetivo deste estudo in vitro foi de avaliar a influencia do tempo de tratamento no desempenho de dentifrícios fluoretados nano-encapsulados na remineralizagao de lesoes cariosas iniciáis. Noventa e seis amostras de esmalte humano foram divididas em oito grupos (n = 12): 50% NanoF + 50% NaF livre, 100% NanoF, 100% NaF (controle positivo) e Placebo (controle negativo) com dois tempos diferentes (um e cinco minutos). Após a indugao da lesao cariosa, os espécimes foram submetidos a um modelo de ciclagem de pH por sete dias. A microdureza superficial foi medida antes e após a indugao da lesao cariosa e após o tratamento. O percentual de remineralizagao superficial foi calculado para cada tempo de estudo. Os dados foram analisados pelo ANOVA e ANOVA de medidas repetidas, seguida de Bonferroni (p <0,05). Diferengas de remineralizagao foram observadas nos dentifrícios de acordo com o tempo de tratamento utilizado. Formulagoes NanoF com 50% (tratamento de um minuto) e 100% (tratamento de cinco minutos) promoveram uma remineralizagao do esmalte, após o desafio cariogènico, quando comparado com o dentifricio placebo (p <0,05). Assim, o tempo foi considerado um fator importante para o sistema de liberagao de flúor. A nanotecnologia pode ser um sistema promissor de remineralizagao da cárie, por disponibilizar o flúor por maior tempo na superficie dentària.

ABSTRACT The aim of this in vitro study was to evaluate the influence of treatment time on the remineralization performance of nanoencapsulated fluoride dentifrices on initial carious lesions. Ninety-six human enamel samples were allocated to eight groups (n = 12): 50% NanoF + 50% free NaF, 100% NanoF, 100% NaF (positive control), and placebo (negative control), using two different treatment times (one and five minutes) for each dentifrice tested. After the carious lesion induction, the specimens were submitted to a pH remineralizing cycling model for seven days. Surface microhardness was measured before and after carious lesion induction and after treatment. The percentage of surface remineralization was calculated for each study time. Data were analyzed using two-way ANOVA and ANOVA repeated-measures tests followed by the Bonferroni correction (p < 0.05). Remineralization differences were observed in the dentifrices analyzed according to the treatment time used. NanoF formulations with 50% (one-min treatment) and 100% (five-min treatment) promoted significant remineralization of enamel after the caries challenge when compared to the placebo dentifrice (p < 0.05). Thus, time was considered an important factor for the fluoride release system. Nanotechnology can be a promising system for caries remineralization as it makes fluoride available on the dental surface for a longer time.

Abstract This study aims to develop a nano-sized fluoridated layered double hydroxide (LDH)-based release system via hydrothermal treatment for the controlled delivery of fluoride (F-) ions in the oral environment. The synthesis of conventional LDH-type (C-LDH) precursor nanomaterials was conducted using a co-precipitation method at constant pH, and the nanoparticulate-LDH (N-LDH) was synthesized by a hydrothermal procedure. Fluoride LDH (F-LDH) products were obtained through indirect synthesis using the precursor ion-exchange technique by varying the agitation time (2 and 24 h) and temperature (25 and 40 °C) to produce 12 material samples. The materials were characterized by energy dispersive x-ray, hexamethyldisilazane, digital radiography x-ray, Fourier-transform infrared, thermogravimetric analysis, and scanning electron microscopy. Additionally, the F-release kinetic profile was evaluated for 21 d in neutral and acid media with mathematical model analysis. Products with varying F-quantities were obtained, revealing specific release profiles. In general, there was a higher F-release in the acid medium, with emphasis on F-LDH-8. Fluoride-LDH and controlled fluoride delivery was successfully obtained, proving the potential of these nanomaterials as alternative anti-caries agents.

RESUMO Introdução: Exostose é um crescimento ósseo benigno que comumente acomete a mandíbula e a maxila, porém raramente apresenta grandes dimensões. Objetivo: Descrever um caso de exostose palatina de apresentação rara e discutir os principais aspectos clínicos envolvidos. Relato de caso: Paciente, gênero masculino, 66 anos, melanoderma, com história de aumento de volume no palato duro com tempo de evolução indeterminado, sem queixas álgicas, porém relatava transtornos de mastigação e fonação. O conjunto da lesão obliterava toda a profundidade do palato e ocupava grande volume na cavidade oral. A Tomografia Computadorizada de Feixe Cônico demonstrava áreas bem corticalizadas na superfície da lesão e áreas centrais menos hiperdensas, compatíveis com osso medular maduro. Após exames e pareceres pós-operatórios o paciente foi submetido a tratamento cirúrgico sob anestesia geral para remoção da massa óssea e osteoplastia subjacente, a fim de dar contornos normais ao palato, e o material colhido foi enviado para a biópsia que estabeleceu o diagnóstico de exostose. O paciente evoluiu sem complicações. Conclusão: Embora a exostose seja um crescimento ósseo benigno, ela causou problemas funcionais ao paciente, necessitando assim de um tratamento cirúrgico. Após três meses da remoção, os distúrbios foram revertidos à normalidade, e a sua reabilitação protética está em andamento.

ABSTRACT Introduction: Exostosis is a benign bone growth that commonly affects the jaw and maxilla, but is rarely large. Objective: Describe a case of rare palatal exostosis and discuss the main clinical aspects involved. Case presentation: A case is presented of a male 66-year-old dark-skin patient with a history of hard palate enlargement of an indefinite time of evolution, and chewing and phonation disorders. The lesions had obliterated the entire palatal depth and occupied a large section of the oral cavity. Cone beam computed tomography revealed corticalized areas on the surface of the lesion and less hyperdense central areas compatible with mature bone marrow. After preoperative examination and advice, the patient underwent surgical treatment under general anesthesia to remove the bone mass and underlying osteoplasty to obtain normal palatal contours. The material collected was sent for biopsy testing, which established the diagnosis of exostosis. The patient recovered without any complications. Conclusions: Although exostosis is a benign bone growth, in this case it caused functional problems to the patient, thus requiring surgical treatment. Three months after removal, the disorders have been reverted to normal and prosthetic rehabilitation is underway.

RESUMEN Introducción: La exostosis es un crecimiento óseo benigno que generalmente afecta la mandíbula y el maxilar, pero rara vez es grande. Objetivo: Describir un caso de exostosis palatina rara y discutir los principales aspectos clínicos involucrados. Presentación del caso: Paciente masculino de 66 años, melanoderma, con antecedentes de aumento de volumen del paladar duro con una evolución de tiempo indefinido, trastornos de masticación y fonación El conjunto de lesiones borró toda la profundidad del paladar y ocupó un gran volumen en la cavidad bucal. La tomografía computarizada de haz cónico mostró áreas corticalizadas en la superficie de la lesión y áreas centrales menos hiperdensas, compatibles con la médula ósea madura. Después de los exámenes y consejos preoperatorios, el paciente se sometió a un tratamiento quirúrgico con anestesia general para eliminar la masa ósea con osteoplastia subyacente a fin de obtener contornos del paladar normales, y el material recolectado fue enviado para realizar biopsia que estableció el diagnóstico de exostosis. El paciente progresó sin complicaciones. Conclusiones: Aunque la exostosis es un crecimiento óseo benigno, causó problemas funcionales al paciente, por lo que requirió tratamiento quirúrgico. Tres meses después de la extracción, los trastornos han vuelto a la normalidad y su rehabilitación protésica está en proceso.

Abstract Objective: To evaluate the erosive potential of different alcoholic beverages according to pH, titratable acidity and buffering capacity. Material and Methods: Thirteen industrialized alcoholic beverages of different brands were selected and divided into five groups according to their type and composition. The pH measurement and titratable acidity for pH 5.5 and 7.0 were performed in triplicate in 50 mL of each beverage. The buffering capacity was calculated based on pH and titratable acidity for pH 7.0. ANOVA, Tukey, and Pearson correlation, with p<0.05, were used for data analysis. Results: Data showed normal distribution by Shapiro-Wilk test. The pH of alcoholic beverages ranged from 2.49 (Miks Ice Tea - Green Fruits) to 7.64 (Smirnoff). The highest values of acid titration (4.68) and buffer capacity (19.97) were observed in Smirnoff Ice. The following correlations (p<0.01) were noted between: pH and titratable acidity; buffering capacity and pH; buffering capacity and titratable acidity. Conclusion: Some beers and alcopops presented erosive potential due to their lower pH associated with high acid titration values. The whisky and sugarcane liquor examined were not potentially erosive.

Resumo Introdução A fluoretação das águas de abastecimento público é uma medida importante na prevenção à cárie dentária. Objetivo O objetivo do presente estudo foi avaliar e monitorar os teores de flúor nas águas de abastecimento público em um município de pequeno porte no Nordeste do Brasil. Material e método O estudo apresenta uma abordagem quantitativa de caráter descritivo. Foram selecionados 3 pontos para realizar coleta das águas duas vezes no mês na zona urbana do município durante 12 meses. A concentração de flúor foi obtida pela média das três leituras das amostras analisadas para cada ponto de coleta e classificadas conforme critério proposto pelo Centro Colaborador do Ministério da Saúde em Vigilância da Saúde Bucal. Resultado Segundo o critério utilizado (0,55 – 0,84 mg/L F), apenas 9,7% das amostras estavam dentro do considerado ideal. Conclusão Observou-se que a fluoretação das águas nesse município foi interrompida, pois muitas amostras de água apresentaram níveis de flúor abaixo dos valores mínimos aceitáveis.

Abstract Introduction Fluoridation of public water supply is an important measure in the prevention of dental caries. Objective This study aimed to monitor the fluoride (F) concentrations of a public water supply with water fluoridation program in a small municipality in the Northeast region of Brazil. Material and method It is a quantitative study with a descriptive approach. Three points of the urban area were selected for collecting water samples twice a month for 12 months. The average of F concentrations was calculated considering these three samples of each collection point at the same occasion. F concentrations in the water samples were determined by potentiometry and the results were classified according to the criterion proposed by criterion set down by Collaborating Center of the Brazilian Ministry of Health for Oral Health Surveillance. The samples were classified according to the best risk-benefit adjustment (0.55 – 0.84 mg F /L). Result Less than 10% of the samples were within the ideal range. Conclusion It was observed that water fluoridation in this municipality was interrupted since many water samples showed f-levels below the minimal acceptable values.

Abstract Aqueous two-phase systems (ATPS) are formed by mixtures of chemical species that, under certain conditions, separate into two immiscible phases, with water as the major component in global terms and, at lower concentrations, polymers, salts, ionic liquids and alcohols, depending on the system type. Different parameters influence ATPS equilibrium such as temperature, alcohol carbon chain size, salt type, pH, etc. The present work aimed to obtain the binodal curves for ATPS made up of ethanol, sodium citrate/ammonium sulfate and water at different temperatures (15, 25 and 35 °C) as well as to evaluate the potential of the ethanol/ammonium sulfate system in anthocyanins partition. The results showed that the increase in temperature did not alter the biphasic region in the temperature range investigated, not influencing the formation of phases. Nonlinear equations were satisfactorily fitted to binodal curves data, except for sodium citrate-containing ATPS at 15 °C. Higher concentration of the overall mixture resulted in longer tie-line of ammonium sulphate-containing ATPS. Higher values of partition coefficient and recovery yield of Syzygium cumini fruit anthocyanins were obtained at longer tie-lines.

Resumo Esta pesquisa teve como objetivo determinar a influência de águas fluoretadas subterrâneas e do dentifrício com 1.100 ppm de fluoreto nos biomarcadores de exposição ao flúor em pré-escolares. Foi realizado um estudo transversal em trinta pré-escolares recrutados em áreas naturalmente fluoretadas e não fluoretadas (n = 15). A ingestão diária total de flúor (TDFI) a partir da dieta e do dentifrício, assim como a excreção urinária diária de flúor (DUFE), foram medidas ao longo de 24 horas. Amostras de unhas foram coletadas duas vezes durante 30 dias. As análises de flúor foram realizadas usando um eletrodo específico para íon flúor. Os dados foram analisados utilizando o teste t de Student e pareado, a análise de correlação de Pearson, e a análise de regressão linear múltipla (a≤0,05). As águas subterrâneas e dentifrícios fluoretados foram as fontes dominantes (r2>0,83) do TDFI em crianças da área naturalmente fluoretada e não fluoretada, respectivamente. Uma correlação positiva entre TDFI e DUFE (r=0,50) e entre [F] nas unhas das mãos e dos pés (r=0,60) foi encontrada em crianças da área naturalmente fluoretada. A [F] nas unhas das mãos e dos pés não foi correlacionada com TDFI. O consumo de águas subterrâneas fluoretadas influenciou a concentração de flúor na urina. Além disso, o uso de dentifrício com 1.100 ppm de fluoreto não influenciou a concentração de fluoreto na urina e nas unhas.

Abstract This research aimed to determine the influence of fluoridated groundwater and 1,100 ppm fluoride dentifrice on biomarkers of exposure to fluoride in preschoolers. A cross-sectional study was performed on thirty preschoolers recruited from naturally fluoridated and non-fluoridated areas (n=15). Total Daily Fluoride Intake (TDFI) from diet and dentifrice, and Daily Urinary Fluoride Excretion (DUFE) was measured over 24 h. Nails samples were collected twice during 30 days. Fluoride analyses were performed using a fluoride-ion-specific electrode. Data were evaluated using the Student and paired t-test, Pearson correlation analysis, multiple linear regression analysis (α≤0.05). Fluoridated groundwater and dentifrice were the dominant sources (r2 > 0.83) of TDFI in children from a naturally fluoridated and a non-fluoridated area, respectively. A positive correlation between TDFI and DUFE (r=0.50), and between [F] in fingernails and toenails (r=0.60) were found in children from a naturally fluoridated area. The [F] in nails of finger and toe were not correlated to TDFI. The consumption of fluoridated groundwater influenced the fluoride concentration in urine. In addition, the use of 1,100 ppm fluoride dentifrice did not influence the fluoride concentration in urine and fingernails.

Resumo Este estudo teve como objetivo avaliar o efeito na qualidade de vida relacionada à saúde bucal (QVRSB) de dois protocolos de tratamento para fluorose dentária, em indivíduos incluídos em um ensaio clínico randomizado. Setenta voluntários, os quais viviam em uma área de fluorose endêmica no Brasil, e que possuíam pelo menos quatro dentes ântero-superiores com índice de Thylstrup e Fejerskov de 1 a 7, foram randomizados em dois grupos de tratamento (n= 35): GI- microabrasão de esmalte; ou GII- microabrasão associada com clareamento caseiro. A microabrasão foi realizada com ácido fosfórico 37% e pedra pomes e, o clareamento caseiro com peróxido de carbamida 10% e uso de moldeira. Os voluntários responderam um questionário antes e 1 mês após o tratamento, visando avaliar mudanças na QVRSB através do instrumento Oral Impact on Daily Performance (OIDP). Diferenças nos escores de impacto geral entre e nos mesmos grupos de tratamento foram analisadas através dos testes Wilcoxon (mesmo grupo) e Mann-Whitney (entre grupos), respectivamente. Alterações no escores dos domínios foram analisadas usando o teste Wilcoxon (a<0.05). Um mês após o tratamento, os indivíduos relataram melhora na QVRSB. Ambos os grupos apresentaram menores escores do OIDP (p<0,001), sem diferença entre eles. Os escores dos domínios comer, limpar os dentes, sorrir e estado emocioal diminuíram após o tratamento para toda a amostra. Concluiu-se que o tratamento com microabrasão melhorou a QVRSB de indivíduos vivendo em uma área de fluorose endêmica independentemente da associação com o clareamento caseiro.

Abstract This study aimed to evaluate the effect on oral health-related quality of life (OHRQoL) of two treatment protocols for dental fluorosis in individuals enrolled in a randomized clinical trial. Seventy volunteers, who lived in a fluorosis endemic area in Brazil, and had at least four maxillary anterior teeth showing fluorosis with a Thylstrup and Fejerskov index from 1 to 7, were randomized into two treatment groups (n= 35): GI- enamel microabrasion; or GII- microabrasion associated with at-home bleaching. Microabrasion was performed using 37% phosphoric acid and pumice, and at-home tooth bleaching with 10% carbamide peroxide in a tray. Volunteers completed a questionnaire at baseline and 1-month post treatment to assess changes in OHRQoL, using the Oral Impact on Daily Performance (OIDP). Differences in overall impact scores between and within treatment groups were analyzed with Wilcoxon (within) and Mann-Whitney (between) tests. Changes in performance scores were analyzed using Wilcoxon tests (a< 0.05). One month after treatment, subjects reported improvement in OHRQoL. Both groups showed lower OIDP scores (p< 0.001), but there was no difference between them. Eating, cleaning teeth, smiling and emotional state performance scores were lower after treatment for the whole sample. In conclusion, the treatment with microabrasion improved the OHRQoL in this sample of individuals living in a fluorosis endemic area regardless of the addition of at-home bleaching.

ABSTRACT The copaiba oleoresin, Copaifera multijuga Hayne, Fabaceae, is a phytotherapeutic agent with antimicrobial activity. This study evaluated the antibacterial activity and cytotoxicity of, and tooth color changes caused by four copaiba oil emulsions (Emulsion 1, 10% CM; Emulsion 2, 10% C. multijuga + 1% biotech product; Emulsion 3, 30% C. multijuga; and Emulsion 4, 30% C. multijuga + 1% biotech product). The antibacterial activities against microorganisms causing dental caries (Streptococcus mutans ATCC25175, S. oralis ATCC10557, S. salivarius ATCC7073, and Lactobacillus casei ATCC7469) were tested using three parameters: minimum inhibitory concentration, minimum bactericidal concentration, and cell viability by fluorescence microscopy. The emulsions were assessed for cytotoxicity by means of the hemolytic assay and cell culture (murine fibroblast cells NHI3T3) using Alamar BlueTM. The dentin color change caused by the emulsions was examined at 10 s, 30 s, and 10 min. The emulsions showed antibacterial activity against the microorganisms tested with an MIC of 125 µl/ml. The minimum bactericidal concentration was higher than minimum inhibitory concentration for the tested microorganism and the fluorescence confirmed that the cells were viable at minimum inhibitory concentration values. The emulsions had a hemolytic activity of 71.16% (Emulsion 3) and 44.67% (Emulsion 4) at a concentration of 30 µl/ml. In cell culture assay, NHI-3T3 cells treated with the emulsions showed 6–16% viability. Emulsion 1 caused clinically imperceptible color change in dentin at 10 s (ΔE = 3.21), Emulsion 2 at 30 s (ΔE = 2.70) and 10 min (ΔE = 3.08), and Emulsion 4 at 10 min (ΔE = 3.03). Emulsion 3 caused color change at all times tested. This research documented positive data regarding antibacterial activity, cytotoxicity, and tooth color changes when using copaiba oleoresin emulsions, showing its potential for use in dentistry.