Digital repair for a patient with limited mouth opening: a case report and literature review / 口腔疾病防治

Objective@#To explore an accurate method to obtain an intraoral model of patients with specific limited mouth opening (microstomia) due to systemic scleroderma.@*Methods@#This study followed medical ethics, and informed consent has been obtained from patients. A case of Ken's Type I mandibular dentition defect scleroderma with limited mouth opening was addressed with digital technology as the leading method combined with the traditional impression method of segmental impression. Individual trays were made based on the patient's left and right mandibular dentition, and segmented molds were obtained. Simultaneously, intraoral scanning was performed to obtain the morphological data of both the soft and hard tissues of the upper and lower mandibles. After each part of the model was obtained, the mandibular model was scanned and digitally aligned to form the final denture model, and the final removable partial denture was designed and made by computer aided design/computer aided manufacturing (CAD/CAM) technology. At the same time, combined with the literature, the diagnosis and treatment of removable partial denture in patients with limited mouth opening were retrospectively analyzed.@*Results@#The denture was well retained and achieved a good repair effect. The patients expressed satisfaction with the mastication efficiency and other functions of the denture. The findings of the literature review show that the integration of digital technology with the traditional impression method, along with computer fitting, can accurately obtain the patient's oral model and facilitate successful follow-up repairs. However, when the anterior mandibular dentition of the patient is absent, the margin of error is increased in this procedure, which deserves further exploration.@*Conclusion@#Utilizing digital technology as the leading method, combined with the traditional impression method of segmental impression, for the repair of dental defects in patients with limited mouth opening, has proven to be effective. Thus, patients report a positive medical experience with high satisfaction, indicating that this approach is worthy of clinical promotion.

Clinical application of lithium disilicate glass ceramic cantilever resin-bonded fixed partial denture in the restoration of single anterior tooth loss / 口腔疾病防治

Objective@#To investigate the clinical effect of lithium disilicate glass ceramic cantilever resin-bonded fixed partial dentures (CRBFPDs) on single anterior tooth loss to provide a reference for the selection of restoration methods for single anterior tooth loss.@*Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. Forty-two patients with less than two anterior teeth with monomaxillary loss were included in this study. After 6 months, 1 year, 2 years, and 3 years, the aesthetic and functional effects of the restorations and the periodontal health status were evaluated, and the visual analog scale (VAS) was used to assess patient satisfaction.@*Results@#During the observation period, the connector fractured in one case within 3 months. One case had debonded within 2 years. The aesthetic restoration effect of all lithium disilicate glass ceramic CRBFPDs was categorized as Class A. The periodontal health was good, there was no clinical absorption in the soft and hard tissues of the abutment or subbridge, periodontal status according to the evaluation indices was classified as class A, and the total satisfaction rate of the patient was 100%.@*Conclusion@#For single anterior tooth loss patients, lithium disilicate glass ceramic cantilever resin-bonded fixed partial denture can achieve the restoration effect of less invasion, better adhesion, aesthetics, comfort and good biocompatibility. With high patient satisfaction, it can be considered an ideal restoration method for replacing a single anterior tooth.

Anti-biofilm effectiveness of protocols for cleaning complete dentures in hospitalized patients: a randomized controlled trial

Abstract Denture biofilm acts as a potential reservoir for respiratory pathogens, considerably increasing the risk of lung infections, specifically aspiration pneumonia, mainly 48h after hospital admission. The establishment of a straightforward, affordable, and applicable hygiene protocol in a hospital environment for the effective control of denture biofilm can be particularly useful to prevent respiratory infections or reduce the course of established lung disease. Objectives To evaluate the anti-biofilm effectiveness of denture cleaning protocols in hospitalized patients. Methodology The maxillary complete dentures (MCDs) of 340 hospitalized participants were randomly cleaned once using one of the following 17 protocols (n=20): brushing with distilled water, toothpaste, or neutral liquid soap (controls); immersion in chemical solutions (1% sodium hypochlorite, alkaline peroxide, 0.12% or 2% chlorhexidine digluconate), or microwave irradiation (650 W for 3 min) combined or not with brushing. Before and after the application of the protocols, the biofilm of the intaglio surface of the MCDs was evaluated using two methods: denture biofilm coverage area (%) and microbiological quantitative cultures on blood agar and Sabouraud Dextrose Agar (CFU/mL). Data were subjected to the Wilcoxon and Kruskal-Wallis tests (α=0.05). Results All 17 protocols significantly reduced the percentage area of denture biofilm and microbial and fungal load (P<0.05). The highest percentage reductions in the area of denture biofilm were observed for 1% hypochlorite solution with or without brushing and for 2% chlorhexidine solution and microwave irradiation only in association with brushing (P<0.05). The greatest reductions in microbial and fungal load were found for the groups that used solutions of 2% chlorhexidine and 1% hypochlorite and microwave irradiation, regardless of the association with brushing (P<0.05). Conclusions A single immersion for 10 min in 1% sodium hypochlorite, even in the absence of brushing, proved to be a straightforward, rapid, low-cost, and effective protocol for cleaning the dentures of hospitalized patients.

Atividade antifúngica de nanofibras de policaprolactona/nistatina: estudo in vitro e in vivo / Antifungal activity of polycaprolactone/nystatin nanofibers: in vitro and in vivo study

Este estudo avaliou a eficácia in vitro e in vivo de mantas de nanofibras (NF) de policaprolactona (PCL) incorporadas com nistatina (NIS) no tratamento da estomatite protética (EP) em modelos animais. NF foram sintetizadas com diferentes concentrações de NIS, totalizando quatro soluções: PCL puro, PCL/NIS 0,045 g, PCL/NIS 0,090 g e PCL/NIS 0,225 g. A liberação da NIS foi analisada por espectroscopia Ultravioleta-Visível. A capacidade das mantas de inibirem o biofilme de Candida albicans, principal fator etiológico da EP, dividindo-se cinco grupos (N=5) compostos por um grupo com controle de células de C. albicans e com PCL puro, além das três concentrações de NIS. A seguir, foi analisada a viabilidade celular em queratinócitos humanos (HaCat) por meio do teste colorimétrico de resazurina. Cinco grupos foram divididos (N=10): controle celular, PCL puro e as três concentrações de NIS. Em modelos animais de ratos Wistar albinos (N=18), dispositivos palatinos (DP) de resina acrílica foram confeccionados simulando próteses totais e utilizados para a indução da EP. Para isso, DP contaminados com C. albicans foram cimentados na região molar da cavidade bucal dos animais e permaneceram em boca por 48 h. Após esse período, os DP foram removidos e os animais foram divididos em três grupos: (C) controle; (B1) com tratamento por mantas de PCL/NIS 0,045 g e (B2) PCL/NIS 0,225 g, com N=6. Então novos DP, livres de contaminação, foram cimentados na cavidade oral dos animais e permaneceu por mais 48 h. Após esse período, os animais foram eutanasiados, a contagem de UFC/ mL foi realizada e os palatos foram coletados para a análise histológica. A curva padrão de NIS obtida apresentou R2 de 0,99. As três concentrações de NF apresentaram liberação de NIS, com pico no tempo de 6 h e valores de 66,26 µg/ mL para PCL/NIS 0,045 g, de 333,87 µg/ mL para PCL/NIS 0,090 g e 436,51 µg/ mL para PCL/NIS 0,225 g, constantes até o fim do experimento. Os grupos com NIS reduziram em 2,5 log10 de crescimento do biofilme fúngico em relação aos grupos sem tratamento, Controle e PCL, sem diferença estatística significativa. Não foi observada citotoxicidade nas células HaCat, com viabilidade celular de 93,7% para PCL/NIS 0,045 g, 72,6% para PCL/NIS 0,090 g e 72,4% para PCL/NIS 0,225 g. A indução da EP nos três grupos foi possível e, porém, sem redução significativa na contagem de UFC/ mL de C. albicans nos grupos B1 e B2. Na análise histológica do grupo C pôde-se observar infiltração de hifas de Candida na camada queratinizada, presença de células inflamatórias formando micro abscessos e um discreto infiltrado inflamatório no tecido conjuntivo subjacente ao epitélio infectado. Nos grupos B1 e B2 não foram encontradas alterações epiteliais, concluindo-se que as NF demonstraram atividade antifúngica in vitro e foram efetivas na prevenção da penetração de hifas no tecido palatino de animais com DP (AU)

This study evaluated the in vitro and in vivo efficacy of nanofiber (NF) mats of polycaprolactone (PCL) incorporated with nystatin (NIS) in the treatment of denture stomatitis (DS) in animal models. NFs were synthesized with different concentrations of NIS, totaling four solutions: pure PCL, PCL/NIS 0.045 g, PCL/NIS 0.090 g, and PCL/NIS 0.225 g. The release of NIS was analyzed by Ultraviolet-Visible spectroscopy. The ability of the mats to inhibit Candida albicans biofilm, the main etiological factor of DS, was assessed by dividing five groups (N=5) composed of a group with C. albicans cell control and with pure PCL, in addition to the three concentrations of NIS. Next, cell viability in human keratinocytes (HaCat) was analyzed using the resazurin colorimetric test. Five groups were divided (N=10): cell control, pure PCL, and the three concentrations of NIS. In albino Wistar rat animal models (N=18), palatal devices (PD) made of acrylic resin were fabricated to simulate total prostheses and used to induce DS. For this, PD contaminated with C. albicans were cemented in the molar region of the animals' oral cavity and remained in the mouth for 48 hours. After this period, the PDs were removed, and the animals were divided into three groups: (C) control; (B1) treated with PCL/NIS 0.045 g mats, and (B2) PCL/NIS 0.225 g, with N=6. Then new, uncontaminated PDs were cemented in the animals' oral cavity and remained for another 48 hours. After this period, the animals were euthanized, UFC/ mL counts were performed, and the palates were collected for histological analysis. The standard NIS curve obtained showed an R2 of 0.99. The three concentrations of NF showed NIS release, with a peak at 6 h and values of 66.26 µg/ mL for PCL/NIS 0.045 g, 333.87 µg/ mL for PCL/NIS 0.090 g, and 436.51 µg/ mL for PCL/NIS 0.225 g, remaining constant until the end of the experiment. The groups with NIS reduced fungal biofilm growth by 2.5 log10 compared to the untreated groups, Control and PCL, with no significant statistical difference. No cytotoxicity was observed in HaCat cells, with cell viability of 93.7% for PCL/NIS 0.045 g, 72.6% for PCL/NIS 0.090 g, and 72.4% for PCL/NIS 0.225 g. Induction of DS in the three groups was possible; however, there was no significant reduction in UFC/ mL counts of C. albicans in groups B1 and B2. Histological analysis of group C revealed infiltration of Candida hyphae in the keratinized layer, presence of inflammatory cells forming micro abscesses, and a discreet inflammatory infiltrate in the connective tissue underlying the infected epithelium. No epithelial alterations were found in groups B1 and B2, concluding that NFs demonstrated in vitro antifungal activity and were effective in preventing hyphal penetration into palatal tissue in animals with PD.(AU)

Is scanning under rubber dam isolation a feasible approach for the execution of indirect restorations? / O escaneamento sob isolamento absoluto é uma técnica viável para execução de restaurações indiretas?

Objective: The aim of the study was to report the aplicability of intraoral scanning while rubber dam isolation is in place. Material and Methods: Female patient, 50 years old, required restorative procedures on teeth 35 and 37. An intraoral scan was initially performed on both arches. Isolation was carried out from 33 to 37, tooth preparation and immediate dentin sealing were carried out. A new scan with the rubber dam in place was performed and a CAD/CAM lithium disilicate hybrid block was digitally designed, milled, crystallized and cemented under the tooth surface with the rubber dam still in position. After completing this stage, the rubber dam was removed, the occlusion was verified, presenting excellent aesthetic and functional results. Results: The absolute isolation process used in the present study works as an excellent device for gingival retraction. Conclusion: The absolute isolation can be recommended in clinical activities of intraoral scanning favoring the quality of the final result of treatments (AU)

Objetivo: O objetivo do estudo foi relatar a aplicabilidade do escaneamento intraoral sob isolamento absoluto. Material e Métodos: Paciente do sexo feminino, 50 anos, necessitou de procedimentos restauradores nos dentes 35 e 37. Uma varredura intraoral foi inicialmente realizada em ambos os arcos. O isolamento absoluto foi feito de 33 a 37, permitindo a realização do preparo dentário e selamento imediato da dentina. Um novo escaneamento com o dique de borracha colocado foi realizado e um bloco híbrido de dissilicato de lítio CAD/CAM foi projetado digitalmente, fresado, cristalizado e cimentado sob a superfície dentária ainda com o dique de borracha em posição. Após a finalização dessa etapa, o dique de borracha foi removido, a oclusão foi verificada apresentando ótimos resultados estéticos e funcionais. Resultados: O isolamento absoluto utilizado no presente estudo funciona como um excelente dispositivo para retração gengival. Conclusão: O isolamento absoluto pode ser recomendado em atividades clínicas de escaneamento intraoral favorecendo a qualidade do resultado final dos tratamentos (AU)

Sobrevivência em fadiga de coroas bioinspiradas bilaminadas: estudo in vitro / Fatigue survival rate of bioinspired bilaminar crowns: in vitro study

O objetivo deste estudo foi avaliar o comportamento biomecânico através da resistência à fadiga e análise por elementos finitos de coroas bioinspiradas bilaminadas com infraestruturas modificadas na superfície vestibular (Estudo A) e utilizando diferentes materiais cerâmicos com módulos elásticos distintos (Estudo B). Para isso, foram confeccionados 90 preparos para coroa total em resina epóxi G10, sobre os quais foram preparadas coroas bioinspiradas de acordo com os seguintes grupos: Estudo A - IC (infraestrutura convencional), IME (infraestrutura modificada estratificada) e IMC (infraestrutura modificada cimentada), todas confeccionadas em dissilicato de lítio (infraestrutura) + porcelana (recobrimento); Estudo B ­ DL+LEU (dissilicato de lítio + leucita), LEU+DL (leucita + dissilicato de lítio), CH+DL (cerâmica híbrida + dissilicato de lítio) e CH+LEU (cerâmica híbrida + leucita). Para o Estudo A, todas as infraestruturas foram usinadas; os recobrimentos dos grupos IC e IME foram confeccionados através da estratificação, e os recobrimentos do grupo IMC foram usinados. Já para o Estudo B, todas as peças foram usinadas, de acordo com o material cerâmico de cada grupo. Em seguida, foi realizada a cimentação adesiva dos recobrimentos sobre as infraestruturas (a depender do grupo) e das coroas sobre os preparos utilizando cimento resinoso fotopolimerizável (Variolink Esthetic LC). Após a cimentação, os espécimes foram submetidos ao teste de fadiga cíclica (10.000 ciclos, 20Hz), e como desfecho foram considerados dois eventos, em que o primeiro foi a ocorrência de trinca e/ou lascamento (evento 1) e o segundo foi a falha catastrófica do conjunto (evento 2). Os valores de carga e número de ciclos para falha em que foram observados os eventos 1 e 2 foram utilizados para realizar a análise de sobrevivência de acordo com Kaplan-Meier e Log-Rank (Mantel-Cox; 95%). As marcas de fratura e o modo de falha das coroas foram avaliados e classificados por estereomicroscópio óptico e microscópio eletrônico de varredura. Por fim, foi realizada análise por elementos finitos (FEA) para ambos os estudos, a fim de avaliar a distribuição de tensões sobre as coroas e interface adesiva. Para o Estudo A, os resultados do teste de fadiga mostraram que, considerando o evento 1 (trinca/lascamento), os grupos IC e IMC apresentaram médias de carga fadiga estatisticamente significantes entre si (733,33 N e 913,33 N, respectivamente), enquanto o grupo IME apresentou média superior (1.020 N). O mesmo foi observado para o número de ciclos em fadiga para todos os grupos. Ao considerar o evento 2 (falha catastrófica), os três grupos apresentaram médias estatisticamente semelhantes entre si (~1.028 N). Os resultados de FEA mostraram que o grupo IC concentrou maior tensão de tração do que os grupos IME e IMC. Para o Estudo B, no teste de fadiga, o grupo DL+LEU apresentou a maior média de resistência à fadiga (evento 1: 913,33 N e evento 2: 1033,33 N), enquanto todas as outras combinações de materiais cerâmicos analisadas foram estatisticamente semelhantes entre si, considerando carga e número de ciclos. Com relação ao FEA, os grupos com cerâmica híbrida (CH+DL e CH+LEU) apresentaram menores picos de concentração de tensão na infraestrutura do que os grupos com cerâmicas vítreas (DL+LEU e LEU+DL), porém, em contrapartida, concentraram maior tensão na interface adesiva. Com isso, conclui-se que a utilização da infraestrutura modificada é uma alternativa viável e promissora para tratamentos reabilitadores, apresentando sobrevivência em fadiga e distribuição de tensões satisfatórias. Além disso, a combinação entre uma infraestrutura de dissilicato de lítio e recobrimento de cerâmica a base de leucita corresponde a melhor abordagem considerando a infraestrutura modificada.(AU)

The objective of this study was to evaluate the biomechanical behavior through fatigue resistance and finite element analysis of bilaminar bioinspired crowns with modified infrastructures on the buccal surface (Study A) and using different ceramic materials with different elastic moduli (Study B). For this, 90 preparations were made for a full crown in G10 epoxy resin, on which bioinspired crowns were prepared according to the following groups: Study A - CI (conventional infrastructure), SMI (stratified modified infrastructure) and CMI (cemented modified infrastructure ), all made of lithium disilicate (infrastructure) + porcelain (veneer); Study B ­ LD+LEU (lithium disilicate + leucite), LEU+LD (leucite + lithium disilicate), HC+LD (hybrid ceramic + lithium disilicate) and HC+LEU (hybrid ceramic + leucite). For Study A, all infrastructures were machined; the coverings of the CI and SMI groups were made through stratification technique, and the veneers of the SMI group were machined. For Study B, all pieces were machined, according to the ceramic material of each group. Then, the veneers were cemented into their infrastructures (depending on the group) and crowns were cemented into preparations using light-cured resin cement (Variolink Esthetic LC). After cementing, the specimens were subjected to the cyclic fatigue test (10,000 cycles, 20Hz), and as an outcome two events were considered: the occurrence of cracking and/or chipping (event 1) and catastrophic failure (event 2). The load (N) and number of cycles to failure in which events 1 and 2 were observed were used to perform the survival analysis according to Kaplan-Meier and Log-Rank (Mantel- Cox; 95%). The fracture marks and failure mode of the crowns were evaluated and classified by optical stereomicroscope and scanning electron microscope. Finally, finite element analysis (FEA) was performed for both studies in order to evaluate the stress distribution over the crowns and adhesive interface. For Study A, the results of the fatigue test showed that, considering event 1 (cracking/chipping), the CI and CMI groups presented average to failure that were statistically significant compared to each other (733.33 N and 913.33 N, respectively), while the SMI group showed higher averages (1,020 N). Same pattern was observed for the number of cycles under fatigue for both groups. When considering event 2 (catastrophic failure), the three groups presented statistically similar means (~1,028 N). The FEA results showed that the CI group concentrated greater tensile stress than the CMI and SMI groups. For Study B, in the fatigue test, the LC+LEU group presented the highest average fatigue resistance (event 1: 913.33 N and event 2: 1033.33 N), while all other combinations of ceramic materials analyzed were statistically similar to each other, considering load and number of cycles. Regarding FEA, the groups with hybrid ceramics (HC+LC and HC+LEU) showed lower stress concentration peaks in the infrastructure than the groups with glass ceramics (LC+LEU and LEU+LC), however, on the other hand, concentrated greater tension at the adhesive interface. With this, it is concluded that the use of modified infrastructure is a viable and promising alternative for oral rehabilitation treatments, presenting satisfactory fatigue survival and adequate stress distribution. Furthermore, the combination of a lithium disilicate infrastructure and a leucite-based ceramic coating corresponds to the best approach considering the modified infrastructure.(AU)

Utility of Panoramic Radiographs in the Screening of Individuals with Edentulous Arches: A Need-Analysis Study

Abstract Objective: To evaluate the utility of panoramic radiographs in pre-prosthetic screening of edentulous arches. Material and Methods: Panoramic radiographs taken for three years were retrospectively analyzed. Observations from the radiographs shall be categorized and classified into either of the two categories, namely: 'findings with minimal impact on denture fabrication' and 'findings which affect denture fabrication and require further evaluation.' Anatomic variations, jaw pathologies, and residual ridge resorption patterns were assessed. Results: This study included the initial screening of 23,020 panoramic radiographs, out of which 505 (showing either one or both edentulous arches) were included for the study purpose. The age range of the subjects was from 21 to 94 years. 52.6% of the radiographs showed positive findings. More than half of the radiographs belonged to the males (52.5%). Hyperpneumatization of the maxillary sinus, crestal position of the mental foramen, and retained root fragments were the most common entities noted in the radiographs. Changes in the mental foramen were significantly higher in males than females (p=0.002). Conclusion: Observations from this study showed that panoramic radiographs have high utility for screening edentulous arches, and they should be used in routine clinical practice before denture fabrication.

Manifestaciones orales en pacientes cubanos con COVID-19 hospitalizados y no hospitalizados: Análisis transversal a través de una encuesta / Oral Manifestations in Hospitalized and Non-Hospitalized Cuban Patients with COVID-19: A Cross-Sectional Analysis through a Survey

Introduction: COVID-19 continues to drive research aimed at elucidating the disease's behavior and clinical aspects for improved diagnosis. Objective: To describe oral manifestations reported through a survey by dentate and denture-wearing Cuban individuals hospitalized due to confirmed COVID-19 infection. Methods: A cross-sectional descriptive study was conducted through a survey, involving Cuban individuals aged 18 years and above, confirmed COVID-19 positive by PCR. Exclusions encompassed smokers, alcoholics, regular medication users, those with poor oral hygiene, and individuals with pre-existing oral manifestations. A questionnaire was administered to over a thousand individuals, of which 264 met the criteria. Variables related to COVID-19 infection and oral hygiene were assessed. Data were processed using SPSS, adhering to ethical principles. Results: The study comprised 264 participants with an average age of 39.96 years. Xerostomia emerged as the most prevalent oral manifestation (40.2 por ciento), followed by mandibular pain, TMJ, or bone pain (18.9 por ciento), and non-dental mouth pain (12.5 por ciento). Xerostomia was more prevalent in the 35 to 39 age group, while mandibular pain predominated in the 50 to 54 age group. No statistically significant evidence was found for dentate individuals or denture wearers, but significance was observed for those requiring hospitalization, exhibiting painless tongue lesions, single ulcers, and painful tongue lesions. Conclusions: Xerostomia was the most prevalent oral manifestation, followed by mandibular pain, TMJ or bone pain, and non-dental mouth pain. A statistically significant association was noted between the need for hospitalization and certain oral manifestations. The use of dentures was not significantly related to the studied manifestations(AU)

Introducción: La COVID-19 continúa generando interés en investigaciones que buscan esclarecer el comportamiento de la enfermedad y sus aspectos clínicos para facilitar el diagnóstico. Objetivo: Describir las manifestaciones orales informadas por individuos cubanos dentados, con prótesis, que fueron hospitalizados al dar positivo por COVID-19. Métodos: Se llevó a cabo un estudio descriptivo transversal a través de una encuesta con una muestra de individuos cubanos mayores de 18 años, infectados por COVID-19 y confirmados mediante PCR. Se excluyeron fumadores, alcohólicos, usuarios regulares de medicamentos, personas con mala higiene bucal y aquellos con manifestaciones bucales previas a la infección. Se aplicó un cuestionario a más de mil individuos, de los cuales 264 cumplieron con los criterios. Se utilizaron variables relacionadas con la infección por COVID-19 y la higiene bucal. Los datos se procesaron con SPSS, respetando los principios éticos. Resultados: El estudio incluyó a 264 participantes con una edad promedio de 39,96 años. La xerostomía fue la manifestación bucal más prevalente (40,2 percent), seguida por el dolor mandibular, ATM o hueso (18,9 percent) y el dolor de boca no dental (12,5 percent). La xerostomía fue más frecuente en el grupo de 35 a 39 años, mientras que el dolor mandibular predominó en el grupo de 50 a 54 años. No se encontró evidencia estadística significativa para pacientes dentados o portadores de prótesis, pero sí para aquellos que necesitaron hospitalización, con lesiones en la lengua sin dolor, úlceras únicas y lesiones en la lengua con dolor. Conclusiones: La xerostomía fue la manifestación bucal más prevalente, seguida por el dolor mandibular, ATM o hueso, y el dolor de boca no dental. Se observó una asociación estadísticamente significativa entre la necesidad de hospitalización y ciertas manifestaciones bucales. No se encontró significativo el uso de prótesis en relación con las manifestaciones estudiadas(AU)

Reabilitação oral com próteses parciais removíveis após restabelecimento de dimensão vertical de oclusão e tratamento multidisciplinar: relato de caso / Oral rehabilitation with removable partial dentures after restoration of the vertical dimension of occlusion and multidisciplinary treatment: case report

As próteses parciais removíveis (PPRs) são uma alternativa de tratamento viável na prática clínica para reabilitar arcos parcialmente desdentados. Entretanto, o planejamento dessas próteses e preparo bucal prévio são frequentemente negligenciados. O presente artigo tem como objetivo relatar o caso clínico de uma reabilitação oral com PPRs superior e inferior após abordagem multidisciplinar, de modo a enfatizar as fases de um planejamento criterioso e de preparo prévio dos dentes pilares, visando o sucesso e a longevidade da reabilitação. Paciente do sexo masculino de 57 anos de idade compareceu à clínica da Faculdade de Odontologia de Bauru, Universidade de São Paulo, queixando-se da estética de seu sorriso e de algumas ausências dentárias. O indivíduo utilizava uma PPR provisória inferior insatisfatória e apresentava perda de dimensão vertical de oclusão (DVO). Após o exame clínico, radiográfico e estudo do caso em articulador semi-ajustável, realizou-se o planejamento com abordagens restauradoras, endodônticas, periodontais e protéticas. Após tratamento periodontal, foi realizada endodontia dos elementos 12, 15 e 47, confecção de núcleos e coroas nos dentes 12 e 15, restauração a nível gengival para apoio residual no dente 47, restaurações nos dentes 11, 13, 22, 24 e 44 e, por fim, a confecção das PPRs superior e inferior. A abordagem multidisciplinar utilizada neste caso clínico viabilizou o restabelecimento da DVO e possibilitou o sucesso da reabilitação protética(AU)

Removable partial dentures (RPDs) are a viable treatment alternative in clinical practice to rehabilitate partially edentulous arches. However, the planning of these dentures and prior oral preparation are often neglected. This article aims to report the clinical case of an oral rehabilitation with upper and lower RPDs after a multidisciplinary approach, to emphasize the phases of careful planning and prior preparation of the abutment teeth, aiming at the success and longevity of the rehabilitation. A 57-year-old male patient came to the clinic of the Bauru School of Dentistry, University of São Paulo, complaining about the esthetics of his smile and some missing teeth. The subject was using an unsatisfactory lower provisional prosthesis and had a loss of vertical dimension of occlusion (OVD). After the clinical and radiographic examination and the case study in a semi-adjustable articulator, planning was carried out with restorative, endodontic, periodontal and prosthetic approaches. After periodontal treatment, endodontics were performed on elements 12, 15 and 47, creation of cores and crowns on teeth 12 and 15, restoration at the gingival level for residual support on tooth 47, restorations on teeth 11, 13, 22, 24 and 44 and, finally, the making of the upper and lower PPRs. The multidisciplinary approach used in this clinical case enabled the restoration of the OVD and enabled the success of the oral rehabilitation(AU)

The bruxism paradigm in the absence of teeth: observational cross-sectional study in full denture users / O paradigma do bruxismo na ausência de dentes: estudo observacional de corte transversal em usuários de próteses totais

ABSTRACT BACKGROUND AND OBJECTIVES: Bruxism is defined as an activity of the masticatory muscles, which is independent of the teeth presence, so it can occur in total edentulous patients and users of dental prostheses. In this sense, It is therefore necessary to know the clinical manifestations of bruxism in this population. The objective of this study was to evaluate the clinical manifestation and the presence of probable sleep and awake bruxism in a sample of users of full dentures treated at a teaching dental clinic in the city of Ribeirão Preto/SP. METHODS: The adopted sample consisted of 30 patients (mean age 72 years, 18 women/12 men). The following questionnaires were used to assess probable bruxism: Oral Behavior Checklist (OBC), Questionnaire of the American Academy of Orofacial Pain (AADO) and the Depression Anxiety and Stress Scale (DASS-21). The clinical assessment included the identification of wear on the prostheses, tongue indentations, bitten cheek and sensitivity in the masticatory muscles and temporomandibular joints. The data was analyzed using descriptive statistics. RESULTS: The average of use of the dentures were nine years. Six patients (20%) reported self-perceived sleep bruxism, and 11 (36%) reported self-perceived awake bruxism. OBC showed an average total score of 9.8 ± 6.2, with "teeth clenching" being the most described symptom. DASS-21 presented an average of 16.5, and stress, anxiety and depression were within normal limits. The most commonly reported symptoms in the AADO were headache, neck pain, pain and/or difficulty during jaw function and recent trauma to the head, neck or jaws. In the clinical evaluation, 15 (50%) patients had wear on prosthesis, only 2 (6%) had bitten cheek, none had tongue indentations, 4 (13%) had pain during palpation. CONCLUSION: Despite the limitations of the study (cross-sectional, small sample and absence of instrumental evaluation of bruxism), it is possible to conclude that a significant portion of users of total dentures presented probable bruxism, with tooth clenching being the main report and wear on the prosthesis the main clinical manifestation.

RESUMO JUSTIFICATIVA E OBJETIVOS: O bruxismo é definido como uma atividade da musculatura mastigatória, que independe da presença de dentes, portanto pode ocorrer em pacientes desdentados totais e usuários de próteses dentárias. Assim, é preciso conhecer como o bruxismo se manifesta clinicamente nessa população. O objetivo deste estudo foi investigar a presença do provável bruxismo de sono e de vigília em usuários de prótese total atendidos em uma clínica odontológica de ensino em Ribeirão Preto/SP. MÉTODOS: Uma amostra de conveniência foi composta por 30 pacientes (média de 72 anos, 18 mulheres e 12 homens). Os seguintes questionários foram utilizados para avaliar o provável bruxismo: Oral Behavior Checklist (OBC), Questionário da Academia Americana de Dor Orofacial (AADO) e o Depression Anxiety and Stress Scale (DASS-21). A avaliação clínica incluiu a identificação de desgastes nas próteses, língua dentada, bochecha mordiscada e sensibilidade nos músculos mastigatórios e nas articulações temporomandibulares. Os dados foram analisados por meio de estatística descritiva. RESULTADOS: A média de uso das próteses foi de nove anos. Seis indivíduos (20%) relataram bruxismo do sono e 11 (36%) relataram bruxismo de vigília. O OBC apresentou média de escore total de 9,8 ± 6,2, sendo "apertar de dentes" o sintoma mais descrito. O DASS-21 apresentou média total de 16,5, com valores de estresse, ansiedade e depressão dentro da normalidade. Os sintomas mais relatados no AADO foram cefaleia, dores no pescoço, dor e/ou dificuldade durante a função mandibular e trauma recente na cabeça, pescoço ou maxilares. Na avaliação clínica, 15 (50%) dos pacientes apresentaram desgastes na prótese, 4 (13%) dor por palpação, 2 (6%) bochecha mordiscada e nenhum (0%) língua dentada. CONCLUSÃO: Apesar das limitações deste estudo (corte transversal, amostra reduzida e ausência de avaliação instrumental do bruxismo) foi possível concluir que uma parcela significativa de usuários de próteses totais apresentou provável bruxismo, sendo o apertamento dentário o principal relato e desgastes na prótese a principal manifestação clínica.

Invitro Comparative Analysis of the Flexural Strength of 4 Different Commercially Available Provisional Materials Used in Fixed Partial Dentures – An Original Research

Background: Provisional Prosthesis in fixed partial dentures are subjected to Flexure under stress. Selection of appropriate material for fabrication of Provisional is of utmost importance as the Provisional prosthesis has to remain in function till definitive prosthesis is delivered. Material & Methods: Bar type specimens of four different commercially available brands for provisional restorations fabricated according to ADA specification No. 27 and immersed in artificial saliva. The specimens were fractured under 3-point loading test. Results: The flexural strength ranged between 60 to 110 Mpa. BisGMA Auto polymerizing composite resin from Dentsply Caulk shows the highest flexural strength. Conclusion: Within the limitations of this study, the flexural strengths were material specific rather than category one. The BisGMA composite based resin shows significantly higher flexural strength over other materials

Stability of Denture Base Acrylic Resin to Tea, Coffe and Turmeric Solutions: An in Vitro Study

Background: The color stability of commercially available denture base acrylic resins (Lucitone-199, DPI and Travelon-HI) was studied in vitro. Material & Methods: The specimens were exposed to tea, coffee and turmeric solutions at 37 ± 1 °C. Colour measurement of the specimens from each brand of denture base acrylic resin recorded by spectrophotometer. The specimens were washed under distilled water and dried before measuring the colour on 0, 10, 20 and 30 days of immersion and color differences were calculated. Results: Statistically the colour change was significant between and within the groups of different heat cure denture base acrylic resins. Conclusion: Where as Lucitone-199 heat cure showed the highest colour variation in tea and coffee followed by DPI and Travelon-HI.

Relationship between the occlusal plane and three different levels of ala-tragus line in a sample of sudanese adults / Relación entre el plano oclusal y tres niveles diferentes de la línea ala-trago en una muestra de adultos sudaneses

Aim: Correct orientation of the occlusal plane plays a vital role in achieving the perfect occlusal balance and function of complete dentures. This study aimed to evaluate the most reliable posterior reference point of the ala-tragus line (ATL) concerning occlusal plane (OP) in a sample of the dentate Sudanese population. Materials and Methods: A total of 150 subjects with healthy and well-aligned permanent teeth were randomly selected. Right lateral profile photographs were taken with subjects having a fox plane placed intra-orally, contacting the occlusal plane. Reference points corresponding to inferior, middle, and superior borders of the tragus and inferior border of the ala of the nose were marked on photographs. The angles between the lines were measured using the Auto-CAD software program, and the most parallel relationship was determined. Descriptive statistics in terms of means and standard deviations were presented. Independent t-test and one-way ANOVA tests were used to compare as appropriate. A p-value < 0.05 was considered significant. Results: The mean angle formed by the OP and ATL was 8.5±3.69º for the superior level, 4.68±3.13º for the middle line, and 2.89±2.57º for the inferior line. A significant difference was found between the means of the three angles (p< 0.001), while no significant difference (p> 0.05) was found between both genders regarding the measured angles. Conclusions: The line joining the inferior border of the ala of the nose with the inferior border of the tragus of the ear was the most reliable line in terms of parallelism to determine the occlusal plane orientation.

Antecedentes: La orientación correcta del plano oclusal juega un papel vital para lograr el equilibrio oclusal perfecto y la función de las prótesis completas. Este estudio tuvo como objetivo evaluar el punto de referencia posterior más confiable de la línea ala-trago (ATL) con respecto al plano oclusal (OP) en una muestra de la población dentada de Sudán. Materiales y Métodos: Se seleccionaron aleatoriamente un total de 150 sujetos con dientes permanentes sanos y bien alineados. Se tomaron fotografías de perfil lateral derecho de sujetos a los que se les colocó un plano de zorro intraoralmente, en contacto con el plano oclusal. En las fotografías se marcaron los puntos de referencia correspondientes a los bordes inferior, medio y superior del trago y al borde inferior del ala de la nariz. Los ángulos entre las líneas se midieron utilizando el programa de software Auto-CAD y se determinó la relación más paralela. Se presentaron estadísticas descriptivas en términos de medias y desviaciones estándar. Se utilizaron prueba-t independiente y prueba ANOVA unidireccional para las comparaciones, según correspondiera. Se consideró significativo un valor de p<0,05. Resultados: El ángulo medio formado por OP y ATL fue de 8,5±3,69º para el nivel superior, 4,68±3,13º para la línea media y 2,89±2,57º para la línea inferior. Se encontró una diferencia significativa entre las medias de los tres ángulos (p< 0,001), mientras que no se encontró diferencia significativa (p>0,05) entre ambos sexos con respecto a los ángulos medidos. Conclusión: La línea que une el borde inferior del ala de la nariz con el borde inferior del trago de la oreja fue la línea más confiable en términos de paralelismo para determinar la orientación del plano oclusal.

Desarrollo y aplicación de un software educativo bidimensional para el proceso de enseñanza del diseño de Prótesis Parcial Removible / Validation of a two-dimensional educational software for the learning process of the design of Removable Partial Dentures

Objetivo: El objetivo de este estudio fue desarrollar e implementar un software educativo bidimensional para el proceso de aprendizaje del diseño de Prótesis Parciales Removibles.Materiales y métodos: Se utilizó el método científico y procedimientos de evaluación educativa para abordar las necesidades de la asignatura de Prótesis Parcial Removible en la Facultad de Odontología de la UNMSM de Perú en el año 2022. Se utilizó análisis, síntesis y encuestas. Se examinó la aplicabilidad del software y el cumplimiento de los requerimientos de enseñanza y aprendizaje, no sólo en la UNMSM sino en cualquier universidad con requerimientos y características similares. Resultados: La aplicación in-terna del software arrojó un valor final del 96%, mientras que la evaluación de alumnos y docentes mostró un 90% de aceptación, al considerar que el SEDUPPR es sencillo para instalar, sencillo en su manejo y funcionamiento, y es muy útil para aprender diseño de PPR. Conclusiones: El software educativo bidimensional diseñado para el proceso de aprendizaje de Prótesis Parcial Removible es aplicable y puede ser implementado en diferentes ámbitos educativos.

Objective: The objective of this study was to develop and implement a two-dimensional educational software for the learning process of designing Removable Partial Prostheses.Materials and Methods: The scientific method and educational evaluation procedures were utilized to address the needs of the Removable Partial Prosthesis subject in the Fa-culty of Dentistry at the UNMSM in Peru in 2022. Analysis, synthesis, and surveys were used. The software's applicability and fulfillment of teaching and learning requirements were examined, not only at the UNMSM but also in any university with similar require-ments and characteristics. Results: The internal application of the software yielded a final value of 96%, while the evaluation of students and teachers showed a 90% acceptance rate, considering that SEDUPPR is simple to install, easy to use and operate, and is very useful for learn PPR design. Conclusion: The two-dimensional educational software designed for the learning process of Removable Partial Prosthesis is applicable and can be implemented in different educational settings.

Cambios en parámetros masticatorios con prótesis parcial removible para dientes posteriores perdidos / Changes in masticatory parameters with removable partial dentures for missing posterior teeth

Introducción: el reemplazo de dientes perdidos aspira a mejorar la función masticatoria. Aunque hay diferentes opciones para ello, la conveniencia de la prótesis parcial removible (PPR) es su bajo costo. Objetivo: comparar el desempeño masticatorio (DM) después de 20 ciclos masticatorios y al umbral de la deglución (UD) en adultos de 50 a 70 años con dientes posteriores perdidos (DPP), con/sin PPR; y los ciclos hasta la deglución. Material y métodos: estudio transversal en 35 adultos con dientes anteriores y PPR bien ajustadas y utilizadas para comer. El lado de prueba fue el lado con más DPP. El DM se evaluó después de 20 ciclos y al UD utilizando un alimento prueba artificial (Optosil Comfort®) con/sin la PPR en orden aleatorizado. Las partículas se tamizaron para determinar el tamaño medio de partícula (TMP) como medida del DM. Los ciclos se contaron visualmente. Estadística descriptiva y comparaciones con SPSS-v23. Resultados: hubo diferencias significativas (p ≤ 0.05) al masticar con/sin PPR. El TMP fue más pequeño (mejor DM) con la PPR después de 20 ciclos y al UD (3.9 vs 4.4 mm y 3.2 vs 4.2 mm). Los ciclos para llegar al UD disminuyeron con la PPR (40 vs 47). Conclusión: a pesar de una mejora limitada de la función masticatoria, las PPR ayudan a preparar los alimentos en partículas más pequeñas antes de deglutirlas. La mejoría en DM con PPR es de 24% al UD, realizando menos ciclos antes de deglutir sus alimentos (AU)

Introduction: replacement of missing teeth should improve masticatory function. Although there are different options removable partial dentures (RPD) are used due to their lower cost. Objective: to compare masticatory performance (MP) after 20 chewing-cycles and swallowing-threshold (ST) in 50-70 year-old adults with missing posterior teeth (MPT) with and without their cast-metal RPD; chewing cycles until swallowing were also compared. Material and methods: 35 adults participated in this cross-sectional study. Subjects with anterior teeth and welladjusted RPDs, used for eating were included. The side with more MPT was selected as the test side. MP was evaluated after 20 cycles and ST using an artificial test-food (Optosil Comfort®) with/without the RPD (subject-own-control) (randomized order). Chewed particles were sieved to determine medium-particle-size (MPS) as a measure of MP. Chewing cycles were visually counted. Descriptive statistics and comparisons were run with SPSS v23. Results: there were significant differences (p ≤ 0.05) for all parameters when chewing with/without the RPD. MPS was smaller (better MP) with the RPD (3.9 vs 4.4 mm and 3.2 vs 4.2 mm) after 20 cycles and ST respectively. Cycles required to reach ST were less when chewing with the denture (40 vs 47). Conclusion: despite a limited improvement of masticatory function RPDs help patients prepare their food into smaller particles before swallowing. Improvement in MP with RPDs for patients with MPT is 24% at ST and they perform fewer chewing cycles before swallowing food (AU)

Analysis for Key Points of Registration Applications and Difficulties of Process Control of 3D Printed Customized Dentures / 中国医疗器械杂志

With the highlighted advantages of 3D printing technology in the field of dental prosthodontics, there is increasing in the numbers of registration applications for additive manufacturing customized dentures. However, there is still a lack of unified analysis in the core elements of process control, the key points of registration and the safety production quality control. Based on the current research status of the industry, the study is intended to clarify confusion and difficulties, deeply analyse the mechanism of the product defects, sort the core elements of process control, then try to establish a systematic evaluation system from product performance research, key process verification, production quality control and the description of registration files, so that it can provide help for practitioners to clarify research direction, establishing quality management system, improving the efficiency of registration and ensuring product quality.

Research progress on neutrophil extracellular traps in oral infectious diseases / 口腔疾病防治

@#Eutrophils are the first innate immune cells to reach the site of inflammation. Neutrophils produce neutrophil extracellular traps (NETs) that can quickly capture and limit the spread of pathogens, facilitating the removal of pathogens and their debris. Neutrophils in the oral cavity are specifically transformed from circulating neutrophils in the blood, and the number of NETs released by oral neutrophils is much higher than that of circulating neutrophils, thus better maintaining the balance of the oral microenvironment. As a bimorphic fungus, only the mycelium phase of Candida albicans can induce NETs, which is related to the neutrophils' ability to sense the size of pathogenic microorganisms through neutrophil elastase. However, spherical Staphylococcus aureus are much smaller than Candida albicans, and they can still induce NETs. Porphyromonas gingivalis, as one of the microorganisms in the periodontitis complex, induces fewer NETs than Streptococcus oralis and Actinomycetes, which are two common oral microorganisms, and there may be a mechanism allowing them to escape neutrophilic immunity in the early stage of periodontitis. Although the two main pathways of NET production have been studied in detail, the mechanisms involved in the induction of NETs by different microorganisms, especially from oral neutrophils, are not well understood. This review describes the mechanism of the immune effects of pathogenic microorganisms on neutrophil NETs in the oral cavity, providing a reference for the search for therapeutic targets and the development of key drugs for treating oral infectious diseases.

Relation between the risk factors for the severity of denture stomatitis and quality of life of complete edentulous individuals: a cross-sectional study

Abstract Objective To assess the association between risk factors for developing denture stomatitis (DS) and oral health-related quality of life (OHRQoL) in complete denture wearers. Methodology Participants of both sexes, wearing complete dentures, were classified using the modified Newton classification for the absence or the severity of DS and allocated to groups Normal or zero, IA, IB, II, and III. Lifestyle, oral and denture history, and medication use were assessed using specific questionnaires; clinical parameters such as anatomical characteristics of support were evaluated with the Kapur classification; salivary flow (SF) was calculated by the volume of unstimulated saliva per minute; and microbial load was determined by counting colony forming units (CFU) of target microorganisms present in the biofilm collected from dentures and palate. OHIP-EDENT assessed the OHRQoL. Kendall's tau_b and Spearman tests were applied with a significance level of 5%. Results 184 patients (143 female and 41 male) aged 65.5 ± 6.8 years were evaluated. Positive correlations were found for sex (women; p=0.013, r=0.16), individuals who started to consume alcoholic beverages as a young adult (18-27 years) (p=0.008, r=0.22), CFU of Candida spp. (p<0.001, r=0.27 denture; p<0.001, r=0.31 palate); Candida albicans (p=0.004, r=0.22 denture; p=0.003, r=0.25 palate), and Candida glabrata (p=0.004, r=0.22 denture; p=0.001, r=0.27 palate). Moreover, negative correlations with DS were found for CFU of Staphylococcus spp. (p=0.004, r=-0.20 palate) and enterobacteria (p=0.002, r=-0.24 palate), as well as a negative correlation between SF (p=0.009, r=-0.193) and DS. The CFU of Staphylococcus spp. and enterobacteria on the palate significantly correlated with OHRQoL. Conclusion Being female, consuming alcoholic beverages as a young adult, CFU of Candida spp., Candida albicans, Candida glabrata, and salivary flow may be the most significant risk factors for DS. The microbial load of Staphylococcus spp. and enterobacteria seems to influence the quality of life for complete denture wearers.

Prosthetic rehabilitation with removable dentures positively influences quality of life in older patients: a systematic review / A reabilitação protética com próteses removíveis influencia positivamente a qualidade de vida de pacientes idosos: uma revisão sistemática

OBJECTIVE: This systematic review assessed the effects of prosthetic rehabilitation with removable dentures on oral health-related quality of life (OHRQoL) in older adults. METHODS: A comprehensive electronic search was conducted in the PubMed/MEDLINE, Web of Science, and Cochrane databases to identify randomized clinical trials and prospective clinical studies. The included studies evaluated the effects of prosthetic rehabilitation on OHRQoL in patients whose mean age was > 60 years. The interventions included complete dentures, implant-retained overdentures, and removable partial prostheses, with a minimum follow-up period of 1 month after prosthetic rehabilitation. Patient-reported outcome measures, specifically OHRQoL, were the primary outcome. Risk of bias was assessed using the Cochrane RoB 2 tool for randomized clinical trials and the ROBINS-I tool for prospective clinical studies. RESULTS: Eleven articles were considered eligible for the systematic review. The findings indicated that removable dentures improved various OHRQoL domains, mainly functional limitations and physical and psychological disabilities. Retention, stability, comfort, speech, and masticatory efficiency were significantly better with implant overdentures than complete dentures, leading to higher patient satisfaction and OHRQoL. CONCLUSIONS: This systematic review suggests that prosthetic rehabilitation with removable dentures has a positive influence on OHRQoL in older patients. The findings highlight the beneficial impact of implant overdentures and fixed adhesive prostheses for enhancing functional outcomes and patient satisfaction.

OBJETIVO: Esta revisão sistemática avaliou os efeitos da reabilitação protética com próteses removíveis na qualidade de vida relacionada à saúde bucal (QVRSB) em pacientes idosos. METODOLOGIA: Foi realizada uma pesquisa eletrônica abrangente nas bases de dados United States National Library of Medicine/ Medical Literature Analysis and Retrieval System Online ­ PubMed/MEDLINE, Web of Science e Cochrane para identificar ensaios clínicos randomizados (ECR) e estudos clínicos prospectivos. Os artigos selecionados tiveram como foco avaliar o efeito da reabilitação protética na QVRSB em indivíduos com média de idade superior a 60 anos. As intervenções descritas incluíram próteses totais, overdentures suportadas por implantes e próteses parciais removíveis, com acompanhamento mínimo de um mês após a reabilitação protética. As medidas de resultados relatadas pelos pacientes, especificamente QVRSB, foram o desfecho primário. O risco de viés foi avaliado com a ferramenta Cochrane RoB 2 pare ensaios clínicos randomizados e a ferramenta ROBINS-I para estudos clínicos prospectivos. RESULTADOS: Os resultados mostraram que as próteses dentárias removíveis melhoraram vários domínios da QVRSB, principalmente limitações funcionais e físicas e deficiências psicológicas. A retenção, estabilidade, conforto, fala e eficiência mastigatória foram significativamente melhores com overdentures sobre implantes do que com próteses totais, levando a maior satisfação do paciente e QVRSB. CONCLUSÕES: Esta revisão sistemática sugere uma influência positiva da reabilitação protética com próteses removíveis na QVRSB em pacientes idosos. As descobertas destacam o impacto benéfico das overdentures sobre implantes e das próteses adesivas fixas para melhorar os resultados funcionais e a satisfação do paciente

The importance of properly distributing the occlusal load for the correct biomechanics of implant-supported fixed partial dentures: stress analysis in implants, prosthetic components and infrastructures / A importância da distribuição da carga oclusal de forma adequada para a correta biomecânica de prótese parcial fixa implantosuportada: análise das tensões em implantes, componentes protéticos e infraestruturas

ABSTRACT Objective: The present study analyzed the biomechanical behavior of the generated stress on the external surface of the rehabilitation elements (implants, components and infrastructures) according to different occlusion patterns on a fixed partial denture on osseointegrated implants. Method: The experimental groups varied according to the location of the occlusal load applied to the Fixed partial denture, with a total occlusal load of 750N in all groups, opting for greater loads on the occlusal table of the molar in relation to the premolar. This evaluation was performed by the finite element method with simulations by the AnsysWorkbench 16.0 Software program. Results: The results analyzed for implants and their components showed that the more posterior the occlusal loading, the greater the stress developed (group 4), always in the connection area between the prosthetic component and the implant, as this location can induce greater screw loosening. The results analyzed for the infrastructures showed that the most distributed occlusal loading possible (group 1) is the best situation for generating less stress. However, even in group 3 which obtained the highest stresses in the critical area of the prosthetic connection, the zirconia flexural strength values generated were not worrisome. Conclusion: It can be concluded that the occlusal adjustment of Fixed partial dentures are preponderant and decisive factors for correct biomechanics and preservation of the system in the long term in order to avoid possible damage and/or failures, and exert significant and notorious differences in the behavior of all structures studied herein.

RESUMO Objetivo: O presente estudo analisou o comportamento biomecânico do estresse gerado na superfície externa dos elementos reabilitadores (implantes, componentes e infraestruturas) de acordo com diferentes padrões de oclusão em uma prótese parcial fixa sobre implantes osseointegrados. Métodos: Os grupos experimentais variaram de acordo com a localização da carga oclusal aplicada na Prótese Parcial Fixa, com carga oclusal total de 750N em todos os grupos, optando por cargas maiores na mesa oclusal do molar em relação ao pré-molar. Esta avaliação foi realizada pelo método dos elementos finitos com simulações pelo programa AnsysWorkbench 16.0 Software. Resultados: Os resultados analisados para os implantes e seus componentes mostraram que quanto mais posterior a carga oclusal, maior a tensão desenvolvida (grupo 4), sempre na área de conexão entre o componente protético e o implante, pois este local pode induzir maior soltura do parafuso. Os resultados analisados para as infraestruturas mostraram que a carga oclusal mais distribuída possível (grupo 1) é a melhor situação para gerar menos estresse. No entanto, mesmo no grupo 3 que obteve as maiores tensões na área crítica da conexão protética, os valores de resistência à flexão da zircônia gerados não foram preocupantes. Conclusões: Pode-se concluir que o ajuste oclusal das Próteses Parciais Fixas são fatores preponderantes e decisivos para correta biomecânica e preservação do sistema a longo prazo a fim de evitar possíveis danos e/ou falhas, e exercem diferenças significativas e notórias no comportamento de todas as estruturas aqui estudadas.