O emprego da moldagem digital na prática odontológica - relato de caso / The use of digital molding in dental practice ­ case report

O avanço da tecnologia de digitalização de imagens e desenvolvimento de dispositivos de fresagem possibilitaram a otimização de diversos processos na Odontologia. O emprego do escaneamento intraoral e do sistema CAD-CAM (CAD - Computer Aided Design; CAM - Computer Aided Manufacturing) aprimorou a realização de reabilitações protéticas, permitindo a obtenção de peças de alta qualidade em tempo reduzido. O objetivo deste trabalho é relatar um caso de reabilitação de um incisivo central inferior a partir de escaneamento intraoral, com scanner Omnicam (DentsplySirona Charlotte, NC, EUA) e aplicação do sistema CAD-CAM.

The advancement of image digitization technology and the development of milling devices have made it possible to optimize various processes in Dentistry. The use of intraoral scanning and the CAD-CAM system (CAD - Computer Aided Design; CAM - Computer Aided Manufacturing) has improved the performance of prosthetic rehabilitations, allowing the obtaining of high quality parts in a reduced time. The objective of this work is to report a case of rehabilitation of a lower central incisor using intraoral scanning, with an Omnicam scanner (Dentsply Sirona) and application of the CAD-CAM system.

Effect of the CAD/CAM Milling Protocol on the Fracture Behavior of Zirconia Monolithic Crowns.

Although advancements in CAD/CAM technology allow for more personalized treatments, it is not clear how modifications in the CAD/CAM milling process could affect the restoration surface conditions and their mechanical behavior. The objective of this study was to evaluate the effect of different CAD/CAM milling protocols on the topography and fracture behavior of zirconia monolithic crowns (3Y-PSZ) subjected to a chewing simulation. Monolithic 3Y-PSZ premolar crowns were milled using three protocols (n = 13) (slow (S), normal (N), and fast (F)). Crowns were cemented on a dentin analog abutment and subjected to mechanical aging (200 N, 2 Hz, 1,500,000 cycles, 37 °C water). Surviving crowns were subjected to compressive load test and analyzed using fractography. Fracture load data were analyzed with two-parameter Weibull analysis. The surface topography of the crowns was examined with a stereomicroscope and a 3D non-contact profiler. All crowns survived the chewing simulation. Crowns milled using the F protocol had the greatest characteristic fracture load, while crowns produced with the S protocol showed high Weibull modulus. Groups N and S had a more uniform surface and detailed occlusal anatomy than group F. The CAD/CAM milling protocol affected the topography and mechanical behavior of 3Y-PSZ monolithic crowns.

Influence of crown-lengthening surgery on teeth rehabilitated with ceramic single crowns: A 12-month prospective clinical study.

OBJECTIVE: To compare the clinical periodontal parameters of teeth restored with a single ceramic crown, with and without crown lengthening procedure. METHODS: This prospective, longitudinal, controlled, and single-blinded clinical trial involved 22 patients with a total of forty-one teeth with ceramic crowns. The teeth were divided into two groups: test (n = 21), comprising teeth rehabilitated post crown-lengthening surgery, and control (n = 20), comprising teeth rehabilitated without crown-lengthening surgery. Plaque index (PI), gingival index (GI), probing depth (PD), bleeding on probing (BoP), and clinical attachment level (CAL) were compared between groups (surgically treated and non-surgically treated) and within each group for each type of site (treated -tt; adjacent - ad; and nonadjacent - nad). Additionally, gingival phenotype (GP), gingival recession (GR), and keratinized tissue width (KTW) were also assessed post- restoration. Statistical analyses used a significance level set at 5 %. RESULTS: PI, GI, and BoP were reduced, but no statistically significant differences were observed within each group or between groups for most follow-up periods. CAL of the TT sites was consistently higher in the test group, and PD was also higher in the test group (p < 0.05), except at T3. adPD, nadPD, adCAL, and nadCAL demonstrated no significant differences between groups and periods. A significant association was identified between GP and the occurrence of GR, with the thick-flat phenotype demonstrating less association with GR, regardless of whether crown lengthening was performed or not. CONCLUSION: Crown-lengthening surgery in rehabilitated teeth does not significantly affect PI and GI after 12 months. Although crown-lengthening surgery affected PD and CAL in TT sites, it did not affect adjacent and non-adjacent sites. CLINICAL RELEVANCE: These findings emphasize the importance of considering individual patient factors and the potential impact on periodontal tissues when planning crown-lengthening surgery. Clinicians must have a comprehensive understanding of the dynamics of the periodontal tissues involved in restorative treatments to optimize the procedure, increase success rates, and minimize potential complications.

Adding mechanobiological cell features to finite element analysis of an immediately loaded dental implant.

Finite element analysis (FEA) has been used to analyze the behavior of dental materials, mainly in implantology. However, FEA is a mechanical analysis and few studies have tried to simulate the biological characteristics of the healing process of loaded implants. This study used the rule of mixtures to simulate the biological healing process of immediate implants in an alveolus socket and bone-implant junction interface through FEA. Three-dimensional geometric models of the structures were obtained, and material properties were derived from the literature. The rule of mixtures was used to simulate the healing periods-immediate and early loading, in which the concentration of each cell type, based on in vivo studies, influenced the final elastic moduli. A 100 N occlusal load was simulated in axial and oblique directions. The models were evaluated for maximum and minimum principal strains, and the bone overload was assessed through Frost's mechanostat. There was a higher strain concentration in the healing regions and cortical bone tissue near the cervical portion. The bone overload was higher in the immediate load condition. The method used in this study may help to simulate the biological healing process and could be useful to relate FEA results to clinical practice.

Evaluation of Vertical Misfit and Torque Loss of Different Abutments for Tri-Channel Type Internal Connection Dental Implants After Mechanical Cycling.

The aim of this study was to evaluate the mechanical behavior of UCLA and Mini-conical abutments for implants with Tri-channel connections regarding torque loss and vertical misfit. Twenty 3-element metal-ceramic fixed partial dentures (FPD) supported by 2 implants were manufactured and divided into 2 groups (n = 10): UCLA (group 1) and Mini-conical Abutments (group 2). The evaluation of torque loss was carried out before and after mechanical cycling, while the vertical fit was evaluated throughout the different stages of manufacturing the prostheses, as well pre- and postcycling (300,000 cycles, 30 N). Statistical analyses of torque loss and vertical misfit were performed using the linear mixed effects model. Both groups showed torque loss after mechanical cycling (P < .05); however, there was no significant percentage differences between them (P = .795). Before cycling, the groups showed a significant difference in terms of vertical misfit values (P < .05); however, this difference was no long observed after cycling (P = .894). Both groups showed torque loss after the cycling test, with no significant difference (P > .05). There was no significant difference in vertical misfit after mechanical cycling; however, in group 1 (UCLA) there was accommodation of the implant-UCLA abutment interface, while group 2 (Mini-conical abutment) did not show changes in the interface with the implant after the test. Both groups behaved similarly regarding the torque loss of the prosthesis retention screws pre- and postmechanical cycling, with greater loss after the test.

Orientações de manutenção e higienização de prótese fixa total implantossuportada: revisão de literatura / Guidelines for maintenance and cleaning of implantssupported total fixed prosthesis: literature review

A evolução dos tratamentos em implantodontia possibilitou uma mudança nos tratamentos reabilitadores para pacientes edêntulos, tornando possível a colocação de próteses fixas, que proporcionam maior qualidade de vida para estes pacientes. Para que estas próteses tenham bom desempenho e longevidade satisfatórios é essencial que se mantenha um padrão adequado de higienização bucal e manutenção profissional. Assim, o objetivo deste trabalho foi realizar uma revisão de literatura a respeito dos principais recursos disponíveis para higienização e manutenção das próteses totais fixas sobre implante (protocolo de Branemark), tanto nos cuidados domiciliares dos pacientes quanto no atendimento profissional do cirurgião dentista. Foi realizada uma busca eletrônica, não sistemática, nas bases de dados Lilacs, Pubmed/Medline, Scielo e ScienceDirect, cruzando-se os seguintes descritores: "Higiene Oral"; "Implantes Dentários"; "Implantação Dentária"; "Manutenção"; "Prótese Dentária Fixada por Implante" e "Prótese Dentária". Foram consultados artigos de revisão de literatura, revisão sistemática, meta-análise, estudos clínicos randomizados, além de livros pertinentes ao assunto, publicados no período de 1995 a 2022.Verificou-se na literatura disponível que os principais instrumentos indicados para uso domiciliar são escova dental, fio dental, escova interdental, irrigador oral, dentifrício e enxaguatório. No atendimento profissional em consultório odontológico deve ser dispendida atenção especial às instruções passadas ao paciente e também fazer o possível para motivar e encorajar o seu engajamento na rotina de higienização, além do acompanhamento periodontal, possíveis substituições de parafusos e instalação de placa oclusal estabilizadora, quando necessário. Manter uma higiene oral adequada é essencial para o sucesso das próteses fixas sobre implantes e o cirurgião dentista desempenha um papel crucial não apenas ao realizar o acompanhamento periódico do paciente, mas também ao sugerir os instrumentos mais apropriados, instruir sobre a higiene oral adequada e motivar o paciente a manter a saúde bucal satisfatória(AU)

The evolution of treatments in implantology has enable a change in rehabilitation treatments for edentulous patients, making it possible to place fixed prostheses that provide a better quality of life for these patients. In order to ensure good performance and satisfactory longevity, it is essential to maintain an appropriate standard of oral hygiene and professional maintenance. Thus, the objective of this work was to conduct a literature review on the main resources available for cleaning and maintenance of complete fixed prostheses on implants (Branemark protocol), both in the patients' home care and in the professional care provided by the dentist. A nonsystematic electronic search was carried out in the Lilacs, Pubmed/Medline, Scielo, and ScienceDirect databases, crossing the following descriptors: "Oral Hygiene"; "Dental Implants"; "Dental Implantation"; "Maintenance"; "Dental Prosthesis, ImplantSupported"; and "Prosthodontics". Literature review articles, systematic reviews, meta-analyses, randomized clinical studies, and relevant books on the subject published from 1995 to 2022 were consulted. The literature available indicates that the main instruments recommended for home care are toothbrush, dental floss, interdental brush, oral irrigator, toothpaste, and mouthwash. In the professional dental office, special attention should be given to the instructions given to the patient, as well as to motivate and encourage their engagement in the hygiene routine, in addition to periodontal monitoring, possible screw replacements, and installation of an occlusal splint when necessary. Maintaining adequate oral hygiene is essential for the success of fixed prostheses on implants, and the dentist plays a crucial role, not only in providing periodic patient follow-up, but also in suggesting the most appropriate instruments, instructing on adequate oral hygiene, and motivating the patient to maintain satisfactory oral health(AU)

Antimicrobial activity of essential oils against biofilms formed in dental acrylic resin: a systematic review of in vitro studies.

This study aimed to answer the question formulated according to the PICO strategy: 'Which essential oils show antimicrobial activity against biofilms formed on dental acrylic resin?' composed by population (dental acrylic resin), intervention (application of essential oils), comparison (denture cleansers, antifungal drugs, chlorhexidine, and oral mouthwashes), and outcome (antibiofilm activity). In vitro experimental studies evaluating the activity of EOs on biofilm formed on acrylic resin were included. PRISMA guidelines were followed, and the search was performed in the PubMed, Science Direct, Embase, and Lilacs databases and in the gray literature using Google Scholar and ProQuest in December 2023. A manual search of the reference lists of the included primary studies was performed. Of the 1467 articles identified, 37 were selected for full-text reading and 12 were included. Twelve EOs were evaluated, of which 11 showed activity against Candida spp., 3 against Staphylococcus aureus, and 1 against Pseudomonas aeruginosa. The EOs of Cymbopogon citratus, Cinnamomum zeylanicum, and Cymbopogon nardus showed higher action than chlorhexidine, C. nardus higher than Listerine, C. citratus higher than nystatin, and Melaleuca alternifolia higher than fluconazole and nystatin. However, chlorhexidine was more effective than Lippia sidoides and Salvia officinalis, sodium hypochlorite was more effective than L. sidoides, nystatin was more effective than Zingiber officinale, Amphotericin B more effective than Eucalyptus globulus and M. alternifolia. In conclusion, the EOs of C. zeylanicum, C. citratus, C. nardus, and M. alternifolia showed antimicrobial activity to reduce biofilm on dental acrylic resin.

Complete dentures associated with frailty among edentulous older Japanese people: A prospective analysis.

OBJECTIVE: This study aimed to explore the cross-sectional and prospective associations between self-reported functionality of complete dentures (FCD), satisfaction with complete dentures (SCD) and the ability to chew hard food (ACHF) on the one hand and the frailty index (FI) on the other hand among edentulous community-dwelling older Japanese people. METHODS: The study examined 770 edentulous participants of the Nihon University Japanese Longitudinal Study of Aging. The self-reported FCD, SCD and ability to chew six groups of food (from hardest to softest) with complete dentures were the independent variables at the baseline. The FI was computed including 40 deficits as the dependent variable at the baseline and 4 years later. Cross-sectional and prospective generalized linear regression models were fitted controlling for age, gender, marital status, education, working status and area of residence. RESULTS: The use of non-functional complete dentures and dissatisfaction with complete dentures were both associated with a higher FI cross-sectionally (3.9% [95% CI 2.2-5.6] and 3.2% [95% CI 1.5-4.9], respectively) and prospectively (3.9% [95% CI 2.0-6.0] and 3.3% [95% CI 1.3-5.3], respectively). Regarding the ability to chew, a higher FI at baseline was observed among those able to chew food of Group 2 (1.9%, [95% CI 0.1-3.7]) and Groups 4-6 (1.9%, [95% CI 0.1-3.7]), and a progressive increment in the FI, as the participants reported being able to chew softer groups of food at the follow-up (Group 2: 2.2% [95% CI 0.05-4.3]; Group 3: 3.6% [95% CI 1.2-6.0]; and Groups 4-6: 3.4 [95% CI 0.7-6.1]). CONCLUSION: Self-reported use of non-functional complete dentures, dissatisfaction with dentures and a reduced ACHF with complete dentures were associated with a higher FI both cross-sectionally and prospectively.

The effect of the interproximal contour of single external hexagon implant restorations on the prevalence of peri-implantitis: A retrospective study.

PURPOSE: The objective of this retrospective study was to evaluate the effect of the interproximal contour of single external hexagon implant restorations on the prevalence of peri-implantitis. MATERIAL AND METHODS: Records of 96 patients and 148 external hexagon (EH) implants with time in function ranging from 1 to 17 years were included in the study. The most recent clinical and radiographic data were collected from records and the prevalence of peri-implantitis was defined according to the 2017 World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions. Marginal bone level (MBL), emergence angle (EA), emergence profile (EP), and crown/implant platform horizontal ratio (CIHR) were obtained from periapical radiographs. Dichotomous variables at the patient- and implant level were compared with association tests. Mann-Whitney U-Test was performed to compare continuous quantitative values between the studied groups. Binomial logistic regression was conducted to identify risk indicators associated with the peri-implantitis event at the patient- and implant level, with the significance level set at 5% for all tests. RESULTS: Nineteen patients (19.2%) and 24 implants (16.2%) with a mean time in function of 5.0 ± 4.7 years were classified as having peri-implantitis. No statistically significant differences concerning gender, mean age, implant location in the jaw, or time in function were observed between patients with or without peri-implantitis (p > 0.05). Of 24 implants with peri-implantitis 10 (41.7%) displayed EA ≤ 30° (16.4%) while 14 (58.3%) presented EA > 30° with no statistical difference between the groups (p > 0.05). No statistically significant associations were identified between EA, EP, or CIHR and the prevalence of peri-implantitis. CONCLUSION: The findings seem to indicate that the EA, EP, and CIHR of single restorations over external hexagon implants are not associated with the presence of peri-implantitis. However, prospective studies with larger samples are required to better ascertain such an association in the long term.

An in vitro study using confocal laser scanning microscopy to evaluate the marginal misfits of different implant-supported frameworks.

PURPOSE: This study aimed to develop and evaluate a simple, non-destructive method for assessing the misfit and passivity of implant-retained prostheses frameworks. MATERIALS AND METHODS: To simulate the rehabilitation of a mandible posterior partially edentulous area using 3-unit screw-retained frameworks supported by two implants were fabricated and divided into the following five groups (n = 10 in each group): OP = one-piece framework cast in Co-Cr with the conventional method (control-group); Co-Cr frameworks sectioned and welded by laser (=LAS) or tungsten inert gas (=TIG); Co-Cr CAD-CAM = milled Co-Cr framework; Zir CAD-CAM = milled zirconia framework. The horizontal |X| and vertical |Y| misfits were measured using confocal laser scanning microscopy with one or both screws tightened. Data were analyzed by a two-way ANOVA with repeated measures and Bonferroni correction (α = 0.05). RESULTS: The greatest |X| misfit was observed in the OP group with both screws tightened (290 µm) and one screw tightened (388 and 340 µm). The conventional casting groups sectioned and welded by laser or TIG had lower mean values (235.35 µm, both screws tightened; and 275 µm, one screw tightened) than the OP framework. However, these values still exceeded those of the milled Co-Cr and zirconia frameworks (190 and 216 µm with both screws tightened). Across all reading conditions, every framework subjected to testing consistently maintained vertical |Y| misfit levels below the threshold of 53 µm; however, the milled frameworks exhibited higher vertical misfits than the frameworks obtained by the conventional cast method. CONCLUSIONS: The frameworks, whether cast and sectioned with laser welding or milled from Co-Cr, exhibit improved marginal misfit and enhanced passive fit when compared to other fabrication methods. Additionally, the use of confocal laser scanning microscopy is highly effective for passivity and misfit analysis.

O acesso à prótese dentária na atenção primária no Brasil / Access to dental prosthesis in primary care in Brazil / Acceso a prótesis dental en atención primaria en Brasil

Este artigo tem como objetivo avaliar o acesso à prótese dentária na Atenção Primária em Saúde (APS) no Brasil. É um estudo transversal, em que foram utilizados dados do Programa de Melhoria do Acesso e da Qualidade Atenção Básica (PMAQ-AB), segundo e terceiro ciclos, com enfoque em saúde bucal e atendimento à prótese dentária por estado brasileiro. Ao comparar as Unidades Básicas de Saúde (UBS) que fazem instalações de prótese nos dois ciclos de avaliação, foi observada diferença estatisticamente significativa (teste Mann Whitney, p = 0,04), mostrando maior número de instalações no terceiro ciclo. O percentual de UBS que instalavam prótese dentária no segundo ciclo foi de 8,4% e no terceiro ciclo, 14,1%. Ao se avaliar os locais em que os pacientes fizeram a prótese dentária, verifica-se que a maioria fez suas próteses no serviço privado. Conclui-se, então, que a APS não consegue suprir a demanda por prótese dentária.

This cross-sectional study evaluates access to dental prosthesis in Primary Health Care (PHC) in Brazil. Data were obtained from the Access and Quality Improvement Program (PMAQ-AB), second and third cycles, focusing on oral health and dental care provided by the Brazilian State. Comparison of the Basic Health Units (BHU) that perform prosthesis installations in the two evaluation cycles (Mann Whitney test, p = 0.04) revealed a statistically significant difference, showing a greater number of installations in the third cycle. In the second and third cycles 8.4% and 14.1% of UBS, respectively, installed dental prostheses. When evaluating where patients acquired their dental prosthesis, most sought the private service. In conclusion, PHC cannot meet the demand for dental prosthesis.

Este artículo tuvo por objetivo evaluar el acceso a las prótesis dentales en la atención primaria de salud (APS) en Brasil. Se trata de un estudio transversal que utiliza datos del Programa de Mejoramiento del Acceso y Calidad de la Atención Primaria (PMAQ-AB, por sus siglas en portugués), segundo y tercer ciclo, con foco en salud bucal y atención con prótesis dental por estado brasileño. Al comparar las Unidades Básicas de Salud (UBS) que instalan prótesis en los dos ciclos de evaluación, se observó diferencia estadísticamente significativa (prueba de Mann Whitney, p = 0,04), con un mayor número de instalaciones en el tercer ciclo. El 8,4% de las UBS instalaron prótesis dental en el segundo ciclo, y el 14,1% en el tercer ciclo. En cuanto a los locales donde los pacientes hicieron su prótesis dental, la mayoría fue realizada por el servicio privado. Se concluye que la APS no logra satisfacer la demanda de prótesis dentales.

Splinting or non-splinting of fixed prostheses on adjacent implants: A critical review.

PURPOSE: The present study aimed to identify, through a critical review of the literature, the success factors associated with the splinting of fixed prostheses on adjacent implants of the posterior sectors in partially edentulous patients compared with those not splinted. STUDY SELECTION: A MEDLINE strategy was implemented based on a research question to systematically search and extract information from databases (PubMed and Scopus) using MeSH terms/keywords identified for each domain. Systematic reviews, clinical and in vitro studies were selected and classified according to eligibility criteria based on the research question and level of evidence using the PRISMA flowchart. RESULTS: A total of 32 studies were selected for data extraction and analysis according to study design (three systematic reviews, 14 clinical studies, and 15 in vitro studies). Overall, the studies found no significant difference in the association between the survival rate and prosthesis type. In clinical studies, there have been no differences in marginal bone loss between splinted and non-splinted prostheses, and the influence of peri-implant status and restorative materials has been poorly evaluated. The distribution of stress and loads determined in the in vitro studies showed results that could favor splinted prostheses; however, are generally associated with implant design. CONCLUSIONS: The need for splinted or non-splinted adjacent implant-supported prostheses remains controversial. The reviewed evidence indicates that factors such as implant size and its relationship with coronal height could be important in decision-making.

Biomechanical influence of narrow-diameter implants placed at the crestal and subcrestal level in the maxillary anterior region. A 3D finite element analysis.

PURPOSE: To evaluate the tendency of movement, stress distribution, and microstrain of single-unit crowns in simulated cortical and trabecular bone, implants, and prosthetic components of narrow-diameter implants with different lengths placed at the crestal and subcrestal levels in the maxillary anterior region using 3D finite element analysis (FEA). MATERIALS AND METHODS: Six 3D models were simulated using Invesalius 3.0, Rhinoceros 4.0, and SolidWorks software. Each model simulated the right anterior maxillary region including a Morse taper implant of Ø2.9 mm with different lengths (7, 10, and 13 mm) placed at the crestal and subcrestal level and supporting a cement-retained monolithic single crown in the area of tooth 12. The FEA was performed using ANSYS 19.2. The simulated applied force was 178 N at 0°, 30°, and 60°. The results were analyzed using maps of displacement, von Mises (vM) stress, maximum principal stress, and microstrain. RESULTS: Models with implants at the subcrestal level showed greater displacement. vM stress increased in the implant and prosthetic components when implants were placed at the subcrestal level compared with the crestal level; the length of the implants had a low influence on the stress distribution. Higher stress and strain concentrations were observed in the cortical bone of the subcrestal placement, independent of implant length. Non-axial loading influenced the increased stress and strain in all the evaluated structures. CONCLUSIONS: Narrow-diameter implants positioned at the crestal level showed a more favorable biomechanical behavior for simulated cortical bone, implants, and prosthetic components. Implant length had a smaller influence on stress or strain distribution than the other variables.

Efeito do desenho de preparo e do material restaurador na distribuição de tensões, sobrevivência e carga média de fratura em fadiga de restaurações do tipo overlay / Effect of preparation desings and restorative material on the fatigue behavior and stress distribution of complete coverage onlays

Este estudo avalia o comportamento em fadiga e distribuição de tensões de três desenhos de preparo para overlays (n=21) (com preparo de istmo [IST], com preparo não retentivo [nRET] e sem preparo de istmo [sIST]) e o efeito do material restaurador (resina composta [Tetric CAD] e cerâmica vítrea reforçada por leucita [Empress CAD]) cimentados sobre resina epóxi G10. Com o objetivo de determinar os perfis de carregamento para o ensaio de vida acelerado step-stress (SSALT)), três espécimes de cada grupo foram testados monotônicamente, e os demais foram ensaiados até a fratura, em uma máquina de simulação de mastigação. O número de ciclos e a respectiva carga em que cada espécime falhou foi utilizado para análise de sobrevivência, assim como os dados de espécimes sobreviventes ao teste. Foi realizada a análise de probabilidade Weibull. O modo de falha dos espécimes foi avaliado por estereomicroscopia e microscopia eletrônica de varredura. O comportamento biomecânico foi avaliado utilizando a análise por elementos finitos, e a distribuição de tensão foi avaliada considerando os modelos isotrópicos, linearmente elásticos e homogêneos; uma carga axial (200 N) foi aplicada à superfície oclusal dos molares. A concentração de tensão nas restaurações, interfaces adesivas e estrutura dental foi analisada pelo critério de Tensão Máxima Principal. Houve diferença estatística no SSALT entre nRET-RC (1840,46N) e os demais grupos de estudo, no FEA os grupos LEU absorveram maiores picos de tensão e RC os menores. Os diferentes desenhos de preparo para overlay influenciam a resistência à fratura e a distribuição de tensões em restaurações de cerâmica reforçada com leucita e resina composta para CAD/CAM.(AU)

This study assessed the fatigue behavior and stress distribution of three preparation designs for overlays (n=21) (with isthmus preparation [IST], with non-retentive preparation [nRET], and without isthmus preparation [sIST]) and the effect of the restorative material (composite resin [Tetric CAD] and leucite-reinforced glass ceramic [Empress CAD]) cemented on G10 epoxy resin. To determine the loading profiles for the step-stress accelerated life test (SSALT), three specimens from each group were tested monotonically, and the remainder were tested until fracture, in a chewing simulation machine. The number of cycles and the corresponding load at which each specimen failed were used for survival analysis, along with data from surviving specimens. Weibull probability analysis was performed. The failure mode of the specimens was evaluated through stereomicroscopy and scanning electron microscopy. Biomechanical behavior was assessed using finite element analysis, and stress distribution was evaluated considering isotropic, linearly elastic, and homogeneous models; an axial load (200 N) was applied to the occlusal surface of the molars. Stress concentration in restorations, adhesive interfaces, and dental structure was analyzed using the Maximum Principal Stress criterion. There was a statistical difference in SSALT between nRET-RC (1840.46N) and the other study groups. In FEA, the LEU groups absorbed higher stress peaks, and RC groups absorbed lower ones. The different preparation designs for overlays influence the fracture resistance and stress distribution in leucite-reinforced ceramic and composite resin restorations for CAD/CAM.(AU)

Marginal gap of zirconia and lithium disilicate frameworks produced by the CAD-CAM technique through a comparator microscope ­ in vitro analysis / Fenda marginal de estruturas de zircônia e dissilicato de lítio produzidas pela técnica CAD-CAM através de um microscópio comparador ­ análise in vitro

Objective: The aim of this study was to evaluate the marginal gap of frameworks produced using the CAD-CAM system, from zirconia and lithium disilicate blocks, adapted to a tooth preparation and a gypsum die. Material and Methods: For this study, a human first molar tooth was used as a master model with a full crown preparation. It was molded 20 times to obtain the gypsum die and randomly divided into 2 groups (n=10) for the fabrication of zirconia and lithium disilicate frameworks. The frameworks were made using pre-sintered zirconia blocks and lithium disilicate blocks, both CAD-CAM systems. The marginal gap was measured in µm at four points (buccal, palatal, mesial, and distal) using a comparator microscope with 30x magnification, with the framework seated on the master model (tooth), and on the gypsum die. Marginal gap data (µm) were evaluated using two-way analysis of variance and Tukey's test with a significance level of 5%. Results: The results showed that there was no statistically significant interaction between the factors studied (p=0.223) or isolated factors (ceramic factor p=0.886 and die factor p=0.786). Conclusion: Both ceramics produced using the CAD-CAM technique did not exhibit statistical differences in marginal adaptation on the two types of substrates, both on tooth preparation and on the gypsum die (AU)

Objetivo: O objetivo deste estudo foi avaliar o espaço marginal de estruturas produzidas usando o sistema CAD-CAM, a partir de blocos de zircônia e dissilicato de lítio, adaptadas a um preparo sobre dente e a um troquel de gesso. Material e Métodos: Para este estudo, um dente molar humano foi utilizado como modelo mestre com preparo para coroa total. Este foi moldado 20 vezes para obter o troquel de gesso e dividido aleatoriamente em 2 grupos (n=10) para a fabricação de estruturas de zircônia e dissilicato de lítio. As estruturas foram feitas usando blocos de zircônia pré-sinterizados e blocos de dissilicato de lítio, ambos sistemas para CAD-CAM. O espaço marginal foi medido em µm, em quatro pontos (bucal, palatal, mesial e distal), utilizando um microscópio comparador com ×30 de ampliação e com a estrutura assentada no modelo mestre (dente) e no troquel de gesso. Os dados de espaço marginal (µm) foram avaliados usando análise de variância bidirecional e teste de Tukey com um nível de significância de 5%. Resultados: Os resultados mostraram que não houve interação estatisticamente significativa entre os fatores estudados (p=0,223) ou isoladamente (fator cerâmica p=0,886 e fator troquel p=0,786). Conclusão: Ambas as cerâmicas produzidas usando a técnica CAD-CAM não apresentaram diferenças estatísticas em relação à adaptação marginal nos dois tipos de substratos, tanto na preparação dentária quanto no troquel de gesso(AU)

Relationship between permanent upper anterior teeth and anthropometric facial measures in different populations: a narrative review

Aim: The main purpose of this study was to conduct a narrative review investigating the possible relationship between permanent maxillary anterior teeth and anthropometric facial parameters in different populations. Methods: Searches were performed in the PubMed, BVS (Biblioteca Virtual em Saúde) and SciELO databases to identify relevant scientific articles using the following search terms: "maxillary anterior teeth", "facial measurements" and "anthropometry", in such a way that 218 publications were found. After application of inclusion and exclusion criteria, 13 publications remained for full-text reading. Results: All studies involved male and female samples and it was notorious that male measurements were unanimously higher than those obtained in the opposite sex. The age of the analyzed participants ranged from 17 to 60 years; however, a mean age of 18 to 25 years was the most investigated in literature. In addition, facial measurements including the bizygomatic width, interpupillary distance, intercanthal distance, interalar width and intercommissural width have been proposed to help determine the correct size of anterior teeth. Conclusion: It was concluded that despite the limited number of studies, some factors that influence dental and facial dimensions, such as sex and age, can be identified. However, there is no standardization of the facial or dental parameters used in the studies, a fact that makes it difficult to establish a universal ratio for clinical dental practice

Self-perceived oral health: a study with patients wearing removable dentures

Aim: This study aimed to investigate the relationship between self-perceived oral health and the prosthetic status of individuals who seek care in prosthodontics clinics. Methods: Self-perceived oral health was analyzed through the Geriatric Oral Health Assessment Index (GOHAI). Abutment tooth mobility was assessed, and denture status was determined by clinical assessment of stability, retention, occlusal balance, vertical dimension, and integrity of dentures. The frequency of individuals in each variable was determined for the low and very low GOHAI conditions. Chi-square, Pearson, and stepwise logistic regression tests were used for the statistical analyses (α = 0.05). Results: Ninety wearers of removable dentures with a mean age of 55.1±9.1 years were evaluated. None of the variables was related to GOHAI values (p > 0.05). The regression analysis showed that age predicts (p = 0.006) the variation of GOHAI conditions (OR = 0.924, CI = 0.873- 0.978), showing only 7.6% protective effect against very low GOHAI. Unsatisfactory stability showed the opposite effect (p = 0.034) and the individuals with this characteristic are more likely (OR = 3.055) to have very low GOHAI scores (CI = 1.085- 8.602). Conclusions: The self-perceived oral health of wearers of removable dentures worsens with age and unsatisfactory stability of dentures

Total removal of the buccal flange in maxillary prosthetic preparation: a necessity?: case report / Remoção total do flange vestibular no preparo protético de maxila: uma necessidade?: relato de caso

ABSTRACT Fixed implant-supported complete maxillary dentures aim to rehabilitate aesthetic, phonetic, and functional aspects of edentulous arches. A previous prosthetic preparation without a flange in the anterior sector makes it possible to evaluate the labial support and the existing space for the future prosthesis. Thus, it allows the most appropriate choice of the type of rehabilitation and surgical technique. However, follow-up studies have shown that when proceeding this way, problems in the posterior sector are still occurring, such as the lack of vertical space for an adequate bar design and concave internal designs, which make access to hygiene difficult. Faced with the problem, the aim of this study is to report a clinical case in which the previous prosthetic preparation included the removal of the flange also from the posterior sector during the teeth try-in and the duplication of this assembly in a transparent multifunctional guide that allowed the visualization of the amount of bone removal needed. The osteotomy, performed before the installation of the implants, provided enough space for the bar, acrylic, and prefabricated denture teeth in the prosthesis that was installed, an important fact considering that this is an area with greater chewing efforts. It also allowed for correct internal design in the prosthesis, which will ensure access to correct hygiene. Based on the analysis of the rehabilitated case, it seems fair to conclude that the total removal of the buccal flange at the time of testing the wax try-in of the teeth and its duplication is a differential in the approach of cases and should always be adopted to ensure a lower margin of error and greater longevity in the proposed rehabilitative treatment.

RESUMO Próteses totais fixas implantossuportadas objetivam reabilitar arcos edêntulos nos aspectos estético, fonético e funcional. Um preparo protético prévio sem flange no setor anterior permite avaliar o suporte labial e o espaço presente para a futura prótese, auxilinado na escolha do tipo de reabilitação e da técnica cirúrgica mais adequada. No entanto, estudos de acompanhamento tem mostrado que ao proceder dessa maneira ainda estão ocorrendo problemas no setor posterior, como falta de espaço vertical para um desenho adequado da barra e desenhos internos côncavos, que dificultam o acesso à higienização. Frente ao problema, o objetivo do presente trabalho é relatar um caso clínico no qual o preparo protético prévio incluiu a remoção do flange também do setor posterior durante a prova dos dentes e a duplicação dessa montagem em um guia multifuncional transparente permitindo a visualização da quantidade de remoção óssea necessária. A osteotomia, realizada antes da instalação dos implantes, proporcionou espaço suficiente para a barra, acrílico e dentes de estoque na prótese que foi instalada, fato importante considerando ser essa uma zona com maiores esforços mastigatórios. Também permitiu a confecção de desenho interno correto na prótese, que garantirá o acesso para correta higiene. Com base na análise do caso reabilitado, parece lícito concluir que a remoção total do flange vestibular no momento da prova dos dentes em cera e sua duplicação é um diferencial na abordagem dos casos e que deveria sempre ser adotada para garantir menor margem de erros e maior longevidade no tratamento reabilitador proposto.

How reverse planning and the use o digital devices revolutionize implantology? ­ Case report / Como o planejamento reverso e o uso de ferramentas digitais revolucionam a implantodontia? ­ Relato de caso

Objectives: The aim of the study was to demonstrate how digital devices can be applied in the field of implant dentistry. By integrating data from computed tomography, panoramic radiography, and intraoral scanning into software, it is feasible to perform virtual planning of prosthetic rehabilitation and implant placement predictably. The adoption of reverse planning increases the chances of treatment success. Material and Methods: In this case report, oral rehabilitation of the area of tooth 36 was conducted through implant placement. The implant was installed based on the virtual planning done in the software, followed by the production of a rigid static guide and guided surgery. Results: It was noted that there is a learning curve associated with the use of these technologies, requiring professionals to have theoretical and practical knowledge of digital devices. By using software and surgical guides obtained through 3D printing, it was possible to achieve high precision and preserve vital structures such as blood vessels and nerves, resulting in aesthetic and functional satisfaction for the patient. Conclusion: The use of digital devices in implant dentistry offers speed and predictability in treatment.(AU)

Objetivos: O objetivo do estudo foi evidenciar como as ferramentas digitais podem ser aplicadas na área da implantodontia. Ao integrar dados de tomografia computadorizada, radiografia panorâmica e escaneamento intraoral em um software, é viável realizar o planejamento virtual da reabilitação protética e implante de forma previsível. A adoção do planejamento reverso aumenta as probabilidades de sucesso do tratamento. Material e Métodos: Neste relato de caso, a reabilitação oral da área do dente 36 foi conduzida por meio da instalação de um implante. O implante foi instalado com base no planejamento virtual realizado no software, seguido pela produção de um guia estático rígido e cirurgia guiada. Resultados: Notou-se que há uma curva de aprendizado associada ao uso dessas tecnologias, exigindo que os profissionais possuam conhecimento teórico e prático dos dispositivos digitais. Ao utilizar softwares e guias cirúrgicos personalizados obtidos por impressão 3D, foi possível alcançar alta precisão e preservar estruturas vitais como vasos sanguíneos e nervos, resultando em satisfação estética e funcional para o paciente. Conclusão: O emprego de ferramentas digitais na implantodontia oferece rapidez e previsibilidade no tratamento.(AU)

Dimensional accuracy of provisional complete crown made by the 3D printing method / Acuidade dimensional de coroas totais provisórias confeccionadas pelo método de impressão 3D

Objective: This study evaluated the dimensional accuracy of provisional complete crowns printed with photopolymerizable resin using an LCD-type 3D printer through optical metrology, varying the printing angle and the number of complete crowns printed at once on a single-build platform. Material and Methods: The complete crowns were printed with temporary crown resin, A2 temporary (Wilcos do Brasil), divided into four groups with n=12: Group A - 3 complete crowns positioned at 150° on the x-axis; Group B - 4 complete crowns positioned at 150° on the x-axis; Group C - 3 complete crowns positioned at 180° on the x-axis; and Group D - 4 complete crowns positioned at 180° on the x-axis. Dimensional accuracy was assessed by overlaying images in the Gom Inspect measurement software, where the STL of each complete crown was aligned and compared to the master model. For statistical analysis, one-way ANOVA and Shapiro-Wilk tests were used. Results: No significant statistical difference was observed between the differentangles, or the number of complete crowns printed at once. Conclusion: Based on dimensional accuracy, the printing of provisional complete crowns with an LCD-type 3D printer shows no significant statistical difference with either the 150 or 180-degree angle variations, and there is also no difference when printing 3 or 4 complete crowns at once.(AU)

Objetivo: Este estudo avaliou a acuidade dimensional de coroas totais provisórias impressas com resina fotopolimerizável por uma impressora 3D tipo LCD por meio da metrologia optica, variando angulação de impressão e número de coroas impressas por vez em uma única plataforma de construção. Material e Métodos: As coroas foram impressas com resina para coroa provisória, A2 temporário (Wilcos do Brasil), divididas em quatro grupos com n=12: Grupo A - 3 coroas posicionadas a 150° no eixo x; Grupo B - 4 coroas posicionadas a 150° no eixo x; Grupo C - 3 coroas posicionadas a 180° no eixo x e Grupo D - 4 coroas posicionadas a 180° no eixo x. A acuidade dimensional foi feita com a sobreposição de imagens no programa de aferição Gom Inspect, em que o STL de cada coroa foi alinhado e comparado ao modelo mestre. Para análise estatística, foram utilizados os testes ANOVA um fator e Shapiro-Wilk. Resultados: Não foi verificada diferença estatística significativa entre as diferentes angulações ou quantitadade de coroas impressas em uma única vez. Conclusão: Com base na acuidade dimensional, a impressão de coroas provisórias com impressora 3D tipo LCD não apresenta diferença estatística significative com nenhuma das duas variações angulação de 150 ou 180 graus e não há diferença também ao fazer a impressão de 3 ou 4 coroas de uma única vez.(AU)