Localized Necrotizing Periodontitis: A Possible Oral Manifestation of COVID-19

We investigated an unusual report of localized necrotizing periodontitis coinfection in patients with mild COVID-19. Male patient, 30 years old, with previous medical history of hypovitaminosis, immunized with two doses of the Pfizer® vacci ne, attended in a dental college in northern Brazil with an acute dental emergency reporting itching, halitosis, intense gingival p ain and spontaneous bleeding, mild fever of 37.8ºC, dry cough, muscle pain and nausea. Metronidazole and chlorhexidine were prescribed to improve the necrotizing condition, to treat periodontitis scaling and root planing (SRP) were performed associated with chlo rhexidine irrigation and oral hygiene instructions, which treated the patients conditions. COVID-19 coinfections are possible, specially, oral bacterial infections which is demonstrated in this report, so correct treatment is necessary for both infections. This letter d escribes the first known occurrence of severe localized necrotizing periodontitis in the urban area of Brazil's Amazon region.

Investigamos un reporte inusual de coinfección de periodontitis necrotizante localizada en pacientes con COVID-19 con síntomas leves: Paciente masculino, de 30 años, con antecedentes médicos de hipovitaminosis, inmunizado con dos dosis de la vacuna Pfizer®, atendido en una facultad de odontología en el norte Brasil, con urgencia dental aguda reportando prurito, halitosis, dolor gingival intenso y sangrado espontáneo, fiebre leve de 37,8 ºC, tos seca, mialgias y náuseas. Se prescribió metronidazol y clorhexidina para mejorar el cuadro necrosante, para tratar la periodontitis se realizó raspado y alisado radicular (SRP) asociado a irrigación con clorhexidina e instrucciones de higiene oral. Las coinfecciones por COVID- 19 son posibles, especialmente las infecciones bacterianas orales, lo cual se demuestra en este reporte, por lo que es necesario un correcto tratamiento de ambas infecciones. Esta carta describe la primera aparición conocida de periodontitis necrotizante severa de un paciente del área urbana de la región amazónica de Brasil.

Chemical composition, antimicrobial and antifungal activity of Lippia Thymoide essential oil in oral pathogens

Aim: This study evaluated the chemical composition of Lippia thymoides (Lt) essential oil and its antimicrobial activity against fungal strains of Candida albicans (Ca) and Gram-negative bacteria Prevotella intermedia (Pi) and Fusobacterium nucleatum (Fn). Methods: Lt essential oil was obtained by hydrodistillation apparatus with a modified Clevenger extension. The chemical analysis was analyzed by gas phase chromatography and mass spectrometry on Shimadzu QP 2010 plus. Sample sensitivity evaluation was performed by ABHb-inoculum and culture plates were developed with triphenyltetrazolium chloride, also Fn and Pi samples analysis were in anaerobic environment and Ca sample analysis was performed in aerobic environment. The minimum inhibitory concentration (CIM) was determinated by microdilution in eppendorfs tubes. Results: The chemical analysis showed that Thymol (59,91%) is the main compound found in Lt essential oil, also other antifungal and antimicrobial agents were present γ-terpinene (8.16%), p-cymene (7.29%) and ß-caryophyllene (4.49%), Thymol is a central ingredient of many medicinal plants and has a potent fungicidal, bactericidal and antioxidant activity, it has been previously shown to have anti-inflammatory activity against Periodontal Disease (PD) cause can reduces prostanoids, interleukins, leukotrienes levels in periodontium. CIM result Pi was 6.5 µg/mL, Fn was 1.5 µg/mL and Ca was 0.19 µg/mL. Conclusion: The antimicrobial activity of L. thymoides, through the compound Thymol, has been shown promising potential against gram-negative periodontopathogenic bacteria and fungi whose therapeutic arsenal is still very restricted

Evaluation of tensile strength after insertions andremovals of abutments on frictional Morse taper implants

ABSTRACT: This study aimed to evaluate possible changes in final retention after nine sequences of insertion and removal (SIR) of a frictional Morse taper implant/abutment system, evaluating the force required for dissociating this set between sequences, and verifying possible deformations in the implant heads. Ten implants, 13 mm long and 3.3 mm in diameter, were coupled to a universal mechanical testing machine. Ten anti-rotational abutments, 13 mm long and 3.5 mm in diameter, were connected to the implants parallel to the long axis, using an instrument called beat-connection, and subjected to tensile tests and SEM analysis. The results were analyzed using the Kruskal-Wallis test with Dunn's post-test, and the significance level was set at 5 %. There was no statistically significant difference in final retention among the nine SIRs evaluated. The force needed to uncouple the abutment from the implant increased as SIRs were performed on all ten implants, and an increase of 29.03 % was observed in the ninth SIR compared to the first SIR. After SEM analysis, no significant deformations, fractures, or cracks were observed in the implant heads.

RESUMEN: Este estudio tuvo como objetivo evaluar los posibles cambios en la retención final después de nueve secuencias de inserción y extracción (SIR) de un sistema de implante / pilar de cono de fricción Morse, evaluando la fuerza necesaria para disociar este conjunto entre secuencias y verificando posibles deformaciones en las cabezas de los implantes. Se acoplaron diez implantes, de 13 mm de largo y 3,3 mm de diámetro, a una máquina universal de ensayos mecánicos. Se conectaron a los implantes en paralelo al eje largo diez pilares antirrotacionales, de 13 mm de largo y 3,5 mm de diámetro, mediante un instrumento llamado beat-connection, y se sometieron a pruebas de tracción y análisis SEM. Los resultados se analizaron mediante la prueba de Kruskal-Wallis con la prueba posterior de Dunn, y el nivel de significancia se estableció en 5 %. No hubo diferencias estadísticamente significativas en la retención final entre los nueve SIR evaluados. La fuerza necesaria para desacoplar el pilar del implante aumentó a medida que se realizaban SIR en los diez implantes, y se observó un aumento del 29,03 % en el noveno SIR en comparación con el primer SIR. Después del análisis SEM, no se observaron deformaciones, fracturas o grietas significativas en las cabezas de los implantes.

Doença de Alzheimer como fator de risco à doença periodontal: uma revisão de literatura / Alzheimer's disease as a risk factor to periodontal disease: a literature review

Introdução: A medicina periodontal é a área da periodontia que investiga a interação fisiológica e patológica entre a saúde do periodonto e/ou a Doença Periodontal na saúde sistêmica do individuo. Atualmente estudos evidenciaram possíveis correlações entre a Doença Periodontal e o Alzheimer, nestes trabalhos os autores consideram que estas patologias dividem fatores de risco e/ou modificadores em comum podendo haver uma relação bidirecional entres estas. Objetivo: Realizar uma revisão da literatura para descrever uma correlação entre o Alzheimer e a doença periodontal através dos fatores pro-inflamatórios, imunológicos e periodontopatogênicos. Materiais e Métodos: Foi realizada uma busca na literatura nas bases de dados: Google Acadêmico, PubMed, EBSCO e Scielo, contendo artigos científicos de 2000 até 2019, nos idiomas inglês e português usando os termos de pesquisa e descritores: "Periodontite Crônica" E/OU "Doença de Alzheimer" E/OU "Microbiologia periodontal" E/OU "Citocinas", como critérios de inclusão tivemos estudos de caso-controle, case series e estudos clínicos com criteriosa metodologia, aspectos metodológicos bem organizados estruturalmente e protocolos de pesquisa bem delineados. Conclusão: Consideramos que periodontistas e cirurgiões-dentistas devem estar atentos as possíveis associações entre o Alzheimer e a doença periodontal e durante os atendimentos estar atento aos sinais e sintomas do Alzheimer e orientar a pacientes, familiares e cuidadores quanto a correta higienização bucal, prevenção e tratamento da doença periodontal. (AU)

Introduction: Periodontal medicine is the area of periodontics that investigates the physiological and pathological interaction between periodontal health and / or periodontal disease in the individual's systemic health. Currently, studies have shown possible correlations between Periodontal Disease and Alzheimer's, in these studies, the authors consider that these pathologies divide risk factors and / or modifiers in common, and there may be a bidirectional relationship between them. Objective: To perform a literature review to describe a correlation between Alzheimer's disease and periodontal disease through pro-inflammatory, immunological and periodontopathogenic factors. Materials and Methods: A literature search was performed in the databases: Google Scholar, PubMed, EBSCO and Scielo, containing scientific articles from 2000 to 2019, in the English and Portuguese languages using the search terms and descriptors: "Chronic Periodontitis" E / OR "Alzheimer's Disease" AND / or "Periodontal Microbiology" AND / or "Cytokines", as inclusion criteria we had case-control studies, case series and clinical studies with methodological criteria, well structured methodological aspects and research protocols well outlined. Conclusion: We believe that periodontists and dental surgeons should be aware of the possible associations between Alzheimer's disease and periodontal disease, and during the visits to be alert to the signs and symptoms of Alzheimer's disease and to guide patients, family members and caregivers about correct oral hygiene, prevention and treatment of periodontal disease (AU)

Cisto odontogênico calcificante na maxila posterior: um relato de caso atípico com acompanhamento de dois anos / Calcifying odontogenic cyst in the posterior maxilla: an atypical case report with two-year follow-up

Introdução: o Cisto Odontogênico Calcificante (COC) é um cisto odontogênico raro e indolor, que causa destruição óssea medular e expansão óssea cortical, sendo relatado pela primeira vez por Gorlin, em 1962. Objetivo: neste artigo relatamos um caso de COC na região mais rara de sua aparição, que é a região posterior da maxila em um jovem de apenas 15 anos. Relato de Caso: o paciente foi internado com um inchaço extra-oral, que cresceu lentamente durante os 8 meses anteriores; na cavidade bucal, também foi observado edema na região dos dentes 26, 27 e 28 e também acentuada mobilidade; radiograficamente, havia área radiolúcida unilocular com algumas áreas radiopacas (como uma casca alaranjada). Os achados histológicos observados incluem proliferação de células fantasmas e células basais colunares, semelhantes a ameloblastos e células com camadas superficiais frouxas. Conclusão: o paciente foi submetido à enucleação com curetagem de cisto como tratamento; devido a altas taxas de recorrência, o paciente teve um acompanhamento a cada três meses por um período de 2 anos, sem sinais de recidiva.

Introduction: Calcifying Odontogenic Cyst (COC) is an uncommon and painless odontogenic cyst, that causes bone marrow destruction and cortical bone expansion. It was first reported by Gorlin, in 1962. Objective: in this article, we report a case of COC in the rarest region of its appearance, which is the posterior region of the maxilla in a young man who is only 15 years old. Case Report: the patient was admitted with an extraoral swelling that grew slowly during the previous 8 months; in the oral cavity, edema was also observed in the region of the teeth 26, 27 and 28, and also marked mobility; radiographically, there was unilocular radiolucent area with some radiopaque areas (like an orange skin). The histological findings observed include proliferation of phantom cells, and columnar basal cells, similar to Ameloblasts and cells with loose superficial layers. Conclusion: the patient underwent enucleation with cyst curettage as a treatment; due to high rates of recurrence the patient had a follow up every three months for a period of 2 years without signs of relapse.

Creeping attachment após enxerto gengival livre: relato de caso / Creeping attachment after autogenous free gingival grafting: case report

Introdução: As técnicas de enxerto gengival livre têm como principal objetivo a criação/aumento da faixa de mucosa ceratinizada. Quando se utiliza o tratamento químico da raiz e o correto posicionamento do enxerto no leito receptor podem acarretar em um fenômeno incomumdenominado de Creeping Attachment. Objetivo: descreverum caso de recobrimento radicular apósum enxerto gengival livre e Creeping Attachment. Relato do caso: Paciente sexo masculino, 28 anos de idade, não fumante e sem alterações sistêmicas apresentouse a faculdade de odontologia Universidade Federal de Santa Catarinacom a queixa principal de comprometimento estético e hipersensibilidade dentinária na região anterior-inferior. No exame clínico verificou-se uma recessão gengival unitária no dente 41, classificada como classe I de Miller. Logo indicou-se a cirurgia de enxerto gengival livre, obtido da região de palato duro, visandouma melhora estética efuncional, bem como a remissão da hipersensibilidade. Conclusão: Diante dos resultados clínicos podemos concluir que o enxerto gengival livre é uma técnica previsível e de fácil realização para o aumentoda faixa de mucosa queratinizada para posterior recobrimento radicular, contudo apesar de incomum o fenômeno Creeping Attachment deve ser esperado como alternativa a etapade recobrimento radicular. (AU)

Introduction: Free gingival graft techniques have as main objective the creation / increase of the keratinized mucosa band. When using the chemical treatment of the root surfaceand the correct positioning of the graft in the recipiente bed can lead to anuncommon phenomenon calledCreeping Attachment. Objective: This scientific paper describes a clinical case of root coverage after a free gingival graft and Creeping Attachment. Case Report: A 28-year-old male patient, non-smoker, was assisted in the Federal University of Santa Catarina by students and teachers of dentistry presented the main complaint the aesthetic impairment and dentin hypersensitivity in the anterior region of the jaw. In the clinical examination was observed an unitary gingival recession in tooth 41, classified as Miller class I. The gingival graft surgery, obtained from the hard palate region, was then indicated to improve the esthetic and functional condition, as well as to promove the end of symptoms of hypersensitivity. Conclusion: Inview of the clinical results we can conclude that the free gingival graft is a predictable and easy to perform technique to increase the line of keratinized mucosa for the subsequent root coverage. However, although the Creeping Attachment phenomenon is uncommon, it should be expected as an alternative to the root coverage (AU)

Absence of cytomegalovirus in gingivitis and chronic periodontitis in HIV-1 patients in Northern Brazil

Abstract INTRODUCTION The influence of cytomegalovirus (CMV) on the progression of chronic periodontitis in HIV patients is poorly investigated. METHODS ELISA was used for anti-CMV antibody IgG titer measurements and real-time polymerase chain reaction for qualitative and quantitative CMV detection. Data on the CD4 + T lymphocyte count and plasma HIV viral load were obtained from patient records. RESULTS CMV DNA was detected in samples of subgingival biofilm in only three individuals, two of them with chronic periodontitis (4%) and one with gingivitis (3.3%). CONCLUSIONS The prevalence of CMV is very low both in HIV-1 patients with gingivitis and chronic periodontitis.

Preservação de alvéolo com uso de materiais xenógenos em área estética da maxila: relato de caso / Ridge preservation using xenografts in an aesthetic area of the maxilla: Case Report

INTRODUÇÃO: Para manter as dimensões ósseas e gengivais do alvéolo até a instalação de implantes tardios o cirurgião dentista pode lançar mão de diversas técnicas de regeneração óssea guiada, dentre estas existentes a associação de um substituto ósseo com um selador do alvéolo vem apresentando resultados clínicos satisfatórios. OBJETIVO: O objetivo do presente trabalho é relatar um caso clínico onde a preservação alveolar em área estética maxilar foi realizada com materiais xenógenos. RELATO DE CASO: Paciente gênero feminino com 50 anos, melanoderma, não fumante e sem alterações sistêmicas apresentou-se a pós-graduação em periodontia da Faculdade de Odontologia de Ribeirão Preto devido a incômodo estético nos elementos 11 e 21. No exame clínico verificou comprometimento periodontal extenso nos dentes 11 e 21 sendo indicada a exodontia com reabilitação oral via implantes dentários. O tratamento proposto foram as exodontias seguidas de preservação alveolar com materiais xenógenos para posterior instalação de implantes na área enxertada. Porém a pedido da paciente e por conta das condições periodontais e estéticas as exodontia foram realizadas em momentos diferentes demonstrando um planejamento diferenciado e individualizado. CONCLUSÃO: Podemos concluir que a associação entre o substituto ósseo com a membrana substituta de tecido mucoso conseguiu obter resultados satisfatórios na preservação e manutenção das dimensões ósseas e teciduais no caso apresentado (AU)

INTRODUCTION: To maintain the bone and gingival dimensions of the ridge until the installation of implants the dental surgeon can use several techniques of guided bone regeneration, among these the association of a bone substitute with a ridge's sealant has shown satisfactory clinical results. OBJECTIVE: The objective of this study is to report a clinical case where ridge preservation in maxillary aesthetic area was performed with xenogenic materials. CASE REPORT: A 50-year-old female patient, melanoderma, non-smoker and no systemic conditions presented at post-graduation in periodontics from the Faculty of Dentistry of Ribeirão Preto due to aesthetic discomfort in elements 11 and 21. At the clinical examination it was verified that there was extensive periodontal impairment on teeth 11 and 21, that why it was indicated an oral rehabilitation with dental implants. The proposed treatment was the exodontia followed by ridge preservation with xenogenic materials for posterior implant installation in the grafted area. However, at the request of the patient and due to the periodontal and aesthetic conditions, the exodontia were performed at different times, demonstrating a different and individualized treatment planning. CONCLUSION: We can conclude that the association between the bone substitute and the mucosal tissue replacement membrane was able to obtain satisfactory results in the preservation and maintenance of the bone and tissue dimensions in the presented case.tissue (AU)

Uso da terapia fotodinâmica antimicrobiana em pacientes diabéticos tipo 2 com periodontite crônica: relato de caso / Use of antimicrobial photodynamic therapy in patients with type 2 diabetes and chronic periodontitis: Case report

Introdução: a Terapia Fotodinâmica Antimicrobiana (TFDa) vem sendo considerada como coadjuvante para o tratamento da doença periodontal. Objetivo: Relatar um caso clínico onde a TFDa foi utilizada como tratamento adjuvante a Raspagem e Alisamento Radicular (RAR). Relato de caso: Paciente do gênero masculino, 56 anos de idade, melanoderma, diabetes tipo II, apresentou-se à pós graduação em Periodontia da Faculdade de Odontologia de Ribeirão Preto com a queixa principal de sangramento espontâneo da gengiva e hipersensibilidade generalizada. Durante o exame clínico observou-se higienização deficiente, presença de biofilme bacteriano, cálculos subgengivais, inflamação crônica, bolsas periodontais com Profundidade de Sondagem (PS) ≥ 5 mm e mobilidade dentária, sendo indicado o tratamento periodontal não cirúrgico. O tratamento foi realizado por meio de RAR da boca toda utilizando instrumentos manuais e ultrassônicos e aplicações múltiplas da TFDa como adjuvante a esse tratamento (4 episódios: dias 0, 2, 7 e 14). A TFDa foi realizada com a aplicação do corante de cloridrato de fenotiazina a 10mg/ml na profundidade total bolsa periodontal e em seguida esta foi irradiada com um laser diodo num total de 1 minuto por elemento durante 14 dias. Conclusão: A terapia fotodinâmica antimicrobiana demonstrou que pode ser uma alternativa viável como coadjuvante no tratamento da Doença Periodontal, pois após aplicar o protocolo os parâmetros clínicos como ausência de sangramento gengival, redução na quantidade de biofilme dentário, da mobilidade e diminuição da PS com médias de 3mm puderam ser observados (AU)

Introduction: Antimicrobial Photodynamic Therapy (PDTa) has been considered as a coadjuvant alternative for the treatment of periodontal disease. Objective: To report a case report wherePDTawas performed as an adjuvant treatment to Root Scaling and Planing (RSP). Case report: A 56-year-old male patient, melanoderma, type II diabetes, presented to the post-graduation in Periodontics of the School of Dentistry of Ribeirão Preto with the main complaint of spontaneous bleeding of the gingiva and generalized hypersensitivity. During the clinical examination, deficient hygiene, presence of bacterial biofilm, subgingival calculations, chronic inflammation, periodontal pockets with Probing Depth (PD) ≥ 5 mm and dental mobility were observed, and non-surgical periodontal treatment was indicated. The treatment was carried out by RSP of the whole mouth using manual and ultrasonic instruments and multiple applications of PDTa as an adjuvant to this treatment (4 episodes: days 0, 2, 7 and 14). The PDTa was performed with the application of the 10 mg / ml phenothiazine hydrochloride dye to the total periodontal pocket depth and then it was irradiated with a diode laser in a total of 1 minute per elemento for 14 days. Conclusion: PDTa has shown that it may be a viable alternative as an adjuvant in the treatment of Periodontal Disease, since after applying the protocol clinical parameters such as absence of gingival bleeding, reduction in the amount of dental biofilm, mobility and decrease of PS with averages of 3mm could be observed. (AU)

Analysis of IL-10 in HIV-1 patients with chronic periodontitis in northern Brazil

The objective of this study was to investigate the levels of IL-10 in the gingival crevicular fluid in HIV-1 positive patients with chronic periodontitis and to compare with HIV-1 negative patients with chronic periodontitis, also to correlate clinical periodontal parameters, viral load and count of CD4 + and CD8 + lymphocytes (LTCD4 + and LTCD8 +). Methods: 33 patients were selected and splitted into two groups: 16 HIV-1 positive patients and 17 HIV-1 negative patients and all with chronic periodontitis. The clinical periodontal parameters recorded were: Probing Depth (PD) and Clinical Attachment Level (CAL); the sistemical parameters LTCD4 +, LTCD8 + and viral load were analized by the gingival crevicular fluid collected from all patients. Enzymelinked immunosorbent assay (ELISA) was used to determine the concentrations of Interleukin (IL)-10. For the statistical analysis the Student t, Mann-Whitney and Spearman tests were performed. IL-10 levels were significantly lower in both patients groups. Results: There was statistical difference betwen groups for probing depth (p=0.015) and clinical attachment level (p=0.011), no significant correlation was found among the analyzed variables. Conclusion: The IL-10 levels in HIV-1 positive patients had no influence in periodontal and medical parameters (AU)

Knowledge and attitudes of pregnant women about oral health / Conocimientos y actitudes de las mujeres embarazadas sobre la salud oral

There are evidences that maternal profile, habits and health knowledge, influence in the oral health of children. The aim of this study was to assess pregnant women knowledge on oral hygiene practices and maintenance of Baby´s oral cavity. A descriptive epidemiological survey was conducted with 147 pregnant women. Sample was predominantly formed by young women and 33.33 % had incomplete primary education and most were housewives with family income between 1-2 minimum wages. Family was considered the primary means in the transfer of information about oral hygiene.

Hay evidencia de que los perfiles, hábitos y conocimientos de la salud influyen en la salud oral de los niños. El objetivo de este estudio fue evaluar el conocimiento de las mujeres embarazadas en las prácticas de higiene oral y el cuidado de la cavidad oral del bebé. Una encuesta epidemiológica se llevó a cabo en 147 mujeres embarazadas. La muestra estuvo compuesta predominantemente por mujeres jóvenes, de las cuales el 33,33 % no había completado la escuela primaria y la mayoría eran amas de casa con ingresos familiares entre 1-2 salarios mínimos. La familia fue considerado el principal medio de transmisión de información sobre la higiene oral.

Conditions for oral health in patients with autism / Condiciones de salud oral en pacientes con autismo

Autism is characterized as a behavioral disorder. The autistic patient has some difficulties with common life routines, such as oral hygiene and also improper diet. As a consequence the refusal of physical contact, the implementation of brushing and flossing by caregivers is difficult. The present study aimed to conduct an epidemiological study of autistic patients in treatment at the Rehabilitation Center and Neurological Organization in North of Brazil, adopting the CPO-D and ceo-d. The clinical examination has been performed with the patient sitting in chairs, at the Rehabilitation Centre itself, under artificial fluorescent light intended for room lighting. From 26 patients included in the study, 76.9 % of subjects were male with a mean age of 13 years. Fifty percent had caries, and 11.5% had lesions on the gums. The mean ceo-d of children 2­8 years was 0.67. In patients 10­15 years and 20­40 years, the mean CPO-D was 0.70, and 3.00, respectively. From the study, the most significant data, seen was that half of autistic patients had carious lesions. It is vital to improve oral health conditions in these patients and by using preventive dentistry, analyze their susceptibility to oral diseases.

El autismo se caracteriza como un trastorno conductual. El paciente autista tiene algunas dificultades en las rutinas ordinarias de la vida, tales como la higiene oral. Como consecuencia, la negativa al contacto físico, la implementación del cepillado y uso de hilo dental es difícil para los cuidadores. Este estudio tuvo como objetivo llevar a cabo un estudio epidemiológico de los pacientes autistas en el Centro de Rehabilitación y la organización neurológica en el norte de Brasil, adoptando el CPOD y ceod. El examen clínico se realizó con el paciente sentado en una silla en el propio Centro de Rehabilitación, bajo una luz fluorescente artificial para la iluminación de la habitación. Veintiseis pacientes fueron incluidos en el estudio, el 76,9 % de los sujetos eran varones con una edad media de 13 años con un 50 % de caries, y en un 11,5 % se observaron lesiones gingivales. La media ceod de los niños de 2 a 8 años fue de 0,67. En los pacientes de 10­15 años y 20­40 años, el promedio CPOD fue de 0,70 y 3,00, respectivamente. A partir del estudio se pudo determinar que la mitad de los pacientes autistas tienen caries. Es importante la educación de estos pacientes para mejorar la salud oral y la aplicación de la odontología preventiva.