Cost and effectiveness of 3-dimensionally printed model using three different printing layer parameters and two resins.

STATEMENT OF PROBLEM: When 3-dimensional printing casts, the operator can change the type of resin and the printing layer thickness, reducing the fabrication time. However, how these parameters affect the accuracy of 3-dimensionally printed casts is unknown. PURPOSE: The purpose of this in vitro study was to evaluate the accuracy of 3-dimensionally printed casts by using a stereolithography (SLA) 3-dimensional printer (Forms2) with 3 different layer thickness (25, 50, and 100 µm) and 2 different resins (Gray and Cast) and by comparing the time to obtain each cast. MATERIAL AND METHODS: One master cast was scanned, and a single file was printed several times. The printed casts were then scanned by using a laboratory scanner. The standard tessellation language (STL) files provided by the laboratory scanner were superimposed and compared by using a software program (Geomagic Control; 3D Systems). The 2-way ANOVA test was used for the trueness evaluation, followed by the Tukey test to identify differences among the groups (α=.05). RESULTS: No statistically significant differences in accuracy were found among the 3 different layers for either resin (P>.05). Printing time doubled as layer thickness decreased. CONCLUSIONS: This study showed that when printing casts, the fastest printing settings can be used without losing accuracy and that the laboratory digital workflow can be accelerated with selection of the resin and cast layer, as the type of resin and layer thickness did not influence the quality of the casts.

Hydrophilic titanium surface modulates early stages of osseointegration in osteoporosis.

OBJECTIVE: Using a mouse osteoporotic model, this study aimed to determine the influence of hydrophilic titanium surfaces on gene expression and bone formation during the osseointegration process. BACKGROUND: Based on the previous evidence, it is plausible to assume that osteoporotic bone has a different potential of bone healing. Therefore, implant surface modification study that aims at enhancing bone formation to further improve short- and long-term clinical outcomes in osteoporosis is necessary. MATERIAL AND METHODS: Fifty female, 3-month-old mice were included in this study. Osteoporosis was induced by ovariectomy (OVX, test group) in 25 mice. The further 25 mice had ovaries exposed but not removed (SHAM, control group). Seven weeks following the ovariectomy procedures, one customized implant (0.7 × 8 mm) of each surface was placed in each femur for both groups. Implants had either a hydrophobic surface (SAE) or a hydrophilic treatment surface (SAE-HD). Calcium (Ca) and phosphorus (P) content was measured by energy-dispersive X-ray spectroscopy (EDS) after 7 days. The femurs were analyzed for bone-to-implant contact (BIC) and bone volume fraction (BV) by nano-computed tomography (nano-CT) after 14 and 28 days. Same specimens were further submitted to histological analysis. Additionally, after 3 and 7 days, implants were removed and cells were collected around the implant to access gene expression profile of key osteogenic (Runx2, Alp, Sp7, Bsp, Sost, Ocn) and inflammatory genes (IL-1ß, IL-10, Tnf-α, and Nos2) by qRT-PCR assay. Statistical analysis was performed by ANOVA and paired t test with significance at P < .05. RESULTS: The amount of Ca and P deposited on the surface due to the mineralization process was higher for SAE-HD compared to SAE on the intra-group analysis. Nano-CT and histology revealed more BV and BIC for SAE-HD in SHAM and OVX groups compared to SAE. Analysis in OVX group showed that most genes (ie, ALP, Runx2) involved in the bone morphogenetic protein (BMP) signaling were significantly activated in the hydrophilic treatment. CONCLUSION: Both surfaces were able to modulate bone responses toward osteoblast differentiation. SAE-HD presented a faster response in terms of bone formation and osteogenic gene expression compared to SAE. Hydrophilic surface in situations of osteoporosis seems to provide additional benefits in the early stages of osseointegration.

A fully digital approach for implant fixed complete dentures: A case report.

INTRODUCTIONS: Intraoral scanner has been widely used for implant impression in partially edentulous cases; however, its accuracy in the impression of full-arch implant is still questionable. CLINICAL REPORT: This clinical report presents a technique to check the accuracy of intraoral scanning for complete-arch implant restorations using an implant index cast (The Glossary of Prosthodontic Terms 9th Edition) and a three-dimensional printed cast. A clinical case of immediate loading on a maxillary edentulous patient illustrates the application of an implant index cast in implant fixed complete dentures (IFCDs). DISCUSSION: The implant index cast was fabricated based on the immediate interim prosthesis and provides effective control of the fit of scanned files and printed models. Therefore, this approach allows a more predictable and accurate fit of the final prosthesis. CLINICAL SIGNIFICANCE: In this article, we present a technique to check the accuracy of the final prosthesis without the need for a conventional impression and final cast in a digital workflow. This proposed approach is demonstrated through a case report of a maxillary edentulous patient restored with immediate loaded IFCDs.

Denture scanning technique for computer-guided implant-supported restoration treatment of edentulous patients.

The traditional protocol for guided surgery in a completely edentulous patient is time-consuming, requiring the fabrication of a radiographic guide and a dual cone beam computed tomography (CBCT) scan. Using intraoral scanners to scan the edentulous ridge and the existing denture has been advocated to simplify the process. This technique offers a versatile, precise, and predictable method for the digital planning workflow in edentulous patients for either a fixed or removable restoration. In addition, this approach can help improve the quality of the guide produced by reducing CBCT artifacts associated with the existing denture, as well as capture the soft-tissue contour to further improve the fit of the surgical guide.

Influence of operator experience, scanner type, and scan size on 3D scans.

STATEMENT OF PROBLEM: Intraoral scanners (IOSs) have some inherent distortions caused by optical and/or software imperfections. However, how other factors such as operator experience, scan time, scanner type, and scan size influence scan accuracy is not clear. PURPOSE: The purpose of this in vitro study was to evaluate the trueness and precision of scans performed by 3 professionals with different levels of experience by using 2 IOSs. MATERIAL AND METHODS: Three operators with low, medium, and high levels of experience scanned a master model 10 times by using 2 IOSs (CEREC Omnicam; Dentsply Sirona and TRIOS 3; 3Shape), resulting in 10 standard tessellation language files for each group (N=60). Each standard tessellation language file was divided into 2 areas (prepared teeth and complete arch). Precision was evaluated by comparing the 10 scans from each examiner for each system. Trueness was evaluated by comparing each scan file with a reference scan obtained from a laboratory scanner (D2000; 3Shape). A 3D analysis software program (Geomagic Control; 3D Systems) was used to perform all the comparisons and superimpositions. The 3-way ANOVA test followed by the Tukey HSD test were used to assess precision and trueness. The 2-way ANOVA followed by the Tukey HSD test was used to assess scan time. The Pearson correlation test was performed between scan time and trueness for both scanners. An additional correlation was performed between scan time and number of images, as well as between number of images and trueness for the TRIOS 3. RESULTS: Statistically significant influences of operator (P<.001), scanner (P<.001), scan size (P<.001), operator and scan size (P<.001), and scanner and scan size (P<.001) were observed. The TRIOS 3 group reported higher precision than the CEREC Omnicam group for complete-arch scans (P<.001), although no difference was observed for scans of the prepared tooth. Medium- (P=.002) and low-experience operators (P<.001) reported lower precision for complete-arch scans performed with CEREC Omnicam when compared with TRIOS 3. The low-experience operator reported significantly worse results for complete-arch scans in comparison with the medium- (P=.008 and P<.001) and high-experience operators (P<.001 and P=.001), by using TRIOS 3 and CEREC Omnicam, respectively. Medium- and high-experience operators reported similar results among themselves. The CEREC Omnicam scanner reported lower trueness for complete-arch scans when compared with the prepared tooth (P<.001); for TRIOS 3, a difference was only observed for the low-experience operator when compared with the high-experience operator (P<.001). The CEREC Omnicam reported lower trueness than the TRIOS 3, except for the medium-experience operator with the prepared tooth scan. Comparing the trueness between operators and considering the same scanner and scan size, all groups were similar. The low-experience operator had a longer scanning time than the medium- and high-experience operators. For TRIOS 3, the low-experience operator obtained the highest number of images during each scan. CONCLUSIONS: The accuracy of intraoral scans was influenced by operator experience, type of IOSs, and scan size. More experienced operators and smaller scan sizes made for more accurate scans. In addition, more experienced operators made faster scans, and the TRIOS 3 was more accurate than the CEREC Omnicam for complete-arch scans.

Influence of fabrication method on the marginal fit of temporary restorations.

Computer-aided manufacturing (CAM) technology allows the use of different manufacturing techniques. This in vitro study aimed to evaluate the marginal fit of temporary restorations manufactured using conventional chairside methods, milling, and three-dimensional printing. Fifteen 3-element temporary restorations specimens were produced and categorized into three groups: non-digital, obtained using the conventional chairside method (GC); milled (GM); and three-dimensionally printed (GP). Marginal fit was assessed using scanning electron microscopy (SEM) performed under two conditions: one with only the central screw tightened, and the other with all three screws tightened. Horizontal misfit values were categorized as over-, equal-, and under-extended and qualitatively analyzed. Statistical analysis was performed using the Tukey-Kramer test (α=0.05). In the vertical assessment, three-dimensionally printed restorations demonstrated greater misfit than restorations obtained by milling and the conventional chairside method (P<0.05). In the horizontal assessment, the misfit in the GP group was significantly higher than that in the GM and GC groups. Restorations obtained using the conventional chairside method and milled provisional restorations showed more favorable results than three-dimensionally printed restorations.

Accuracy of Conventional and 3D-Printed Casts for Partial Fixed Prostheses.

PURPOSE: To evaluate and compare the accuracy of conventional and 3D-printed casts using five different 3D printers. MATERIALS AND METHODS: In the control group (CG group, n = 5), five conventional impressions using light- and heavy-body polyvinyl siloxane were obtained from the master model, resulting in five stone models. In the test groups, five different scans were performed by a well-trained and experienced clinician using a TRIOS intraoral scanner. All data were exported in STL file format, processed, and sent to five 3D printers. Five casts were manufactured in each printer group: SG (CARES P20, Straumann); FG (Form 2, Formlabs); WG (Duplicator 7, Wanhao); ZG (Zenith D, Zenith); and MG (Moonray S100, Moonray). Measurements of the accuracy (trueness and precision) of the casts obtained from conventional elastomeric impressions and 3D-printing methods were accomplished using a 3D analysis software (Geomagic Control). RESULTS: The FG group showed the lowest values for trueness (indicating a value closer to real dimensions), which were similar to the SG group only (P > .05). MG, WG, and ZG groups presented higher values and were similar compared to each other. Data on precision demonstrated that all 3D-printed groups showed lower values for precision (smaller deviation) when compared to the CG. CONCLUSIONS: The trueness depends on the chosen 3D printer. All of the tested 3D printers were more precise than cast models obtained from conventional elastomeric impressions.

Accuracy of conventional and 3D printed casts for partial fixed prosthesis.

PURPOSE: To evaluate and compare the accuracy of conventional and 3D-printed casts using five different 3D printers. MATERIALS AND METHODS: In the control group (CG group, n = 5), five conventional impressions using light- and heavy-body polyvinyl siloxane were obtained from the master model, resulting in five stone models. In the test groups, five different scans were performed by a well-trained and experienced clinician using a TRIOS intraoral scanner. All data were exported as an STL file format, processed, and sent to five 3D printers. Five casts were manufactured in each group: SG (CARES P20, Straumann); FG (Form 2, Formlabs); WG (Duplicator 7, Wanhao); ZG (Zenith D, Zenith); and MG (Moonray S100, Moonray). Measurements of the accuracy (trueness and precision) of the casts obtained from conventional elastomeric impressions and 3D-printing methods were accomplished using a 3D analysis software (Geomagic Control). RESULTS: The FG group showed the lowest values for trueness (closer to real dimensions), which were similar to the SG group only (P > .05). Groups MG, WG, and ZG presented higher values and were similar compared to each other. Data on precision demonstrated that all 3D-printed groups showed lower values for precision (smaller deviation) when compared to the control group. CONCLUSION: The trueness depends on the chosen 3D printer. All of the tested 3D printers were more precise than cast models obtained from conventional elastomeric impressions.

Four-Session Protocol Effectiveness in Reducing Cervical Dentin Hypersensitivity: A 24-Week Randomized Clinical Trial.

Objective: A single-blind randomized clinical trial was conducted to evaluate the effectiveness of desensitizing agents with different action mechanisms in reducing cervical dentin hypersensitivity (CDH) after four application sessions, with 24-week follow-up. Materials and methods: Sixty patients with CDH were selected in the study and were allocated in three groups of treatment: Desensibilize KF 2%, Clinpro XT Varnish, and Photon Lase III (100 mW, 4 J/cm2-1 J/cm2 each point, 10 sec per point with wavelength of 808 nm). There were four application sessions performed, with a 48-h interval between each one. The evaporative stimuli and visual analog scale were used to evaluate the CDH level at baseline, immediately after treatment, and at 2, 4, 8, and 24 weeks after the application. Mixed-model effects test was used for comparison (α = 0.05).Results: All three groups showed significant reduction in CDH from baseline to each all-subsequent follow-up. All the groups maintained the CDH reduction, and presented no statistical differences between each other after treatment (p = 0.885), 2 (p = 0.857), 4 (p = 0.928), 8 (p = 0.206), and 24 weeks (p = 0.073) of follow-up.Conclusions: The four-session protocol was an effective approach in reduction of CDH (even after 24 weeks), regardless of desensitization mechanism.

A long-term evaluation of experimental potassium oxalate concentrations on dentin hypersensitivity reduction: A triple-blind randomized clinical trial.

OBJECTIVE: The aim of this split-mouth, triple-blind, randomized clinical trial was to evaluate the long-term clinical efficacy of experimental potassium oxalate concentration (10%) in relieving dentin hypersensitivity (DH), after a four-session application protocol. METHODS: Potassium oxalate gels with different concentrations (5 and 10%) were randomly assigned to half of the 31 patients from the sample in a split-mouth design. The desensitizers were applied following a four-session protocol, one session every 48 h. The primary outcome was the assessment of pain level with the visual analog scale (VAS, 0-10), at baseline, immediately after each desensitizing session, and also after the seventh day and along 1-,3-, 6-, 9- and 12-months follow-ups. Statistical analyses were performed using Friedman repeated measures and Wilcoxon signed rank tests (α = 0.05). RESULTS: For both groups, the minimum of three sessions were required for the achievement of lower DH levels. Regardless of the concentration, the desensitizing effect was maintained all the way to the end of the 6-month follow-up. The 10%-potassium oxalate group was more effective for both 9 and 12-months follow-up periods (p < 0.001). No complications and adverse effects were observed. CONCLUSIONS: When a four-session protocol is applied, both concentrations of potassium oxalate (5 and 10%) proved to be effective on DH reduction for up to six months. However, the higher concentration promoted better long-term results. CLINICAL SIGNIFICANCE: The DH is an increasing condition in clinical practice, which affects the patient's life quality. This study provides primary clinical evidence, suggesting that multiple application sessions and higher concentrations of potassium oxalate may result in maintenance of the desensitizing effect for more extended periods. Trial registered under number: ClinicalTrials.gov NCT03083496.

Reabilitação oral de paciente com redução de dimensão vertical de oclusão utilizando prótese parcial removível overlay: relato de caso / Oral rehabilitation of patient with reduced vertical dimension of occlusion using overlay removable partial denture: case report

A reabilitação oclusal de pacientes parcialmente desdentados com redução da dimensão vertical de oclusão (DVO) representa um grande desafio para o cirurgião-dentista. Normalmente envolve procedimentos complexos, demorados e de elevado custo. A prótese parcial removível (PPR) do tipo overlay representa uma alternativa reabilitadora que pode ser utilizada para esta finalidade. Por meio do relato de um caso clínico, este trabalho teve por objetivo descrever a técnica de utilização da PPR overlay, bem como discutir a viabilidade clínica e efetividade desta modalidade de tratamento. No caso em questão, diagnosticada a redução da DVO, inicialmente a reabilitação oral foi feita de forma provisória, utilizando PPR overlay provisória no arco superior e PPR provisória convencional no arco inferior. O restabelecimento das posições mandibulares possibilitou a reconstrução dos dentes anteriores desgastados com resina composta e a confecção de PPR overlay com recobrimento metálico como tratamento "definitivo". As PPRs de recobrimento (overlays) representam uma excelente e eficiente alternativa no restabelecimento das relações maxilomandibulares. São procedimentos menos onerosos que os procedimentos fixos convencionais, normalmente utilizados na reabilitação de pacientes com diminuição da DVO, mais conservadores e bem indicados para pacientes que tiveram desgastes em função de hábitos parafuncionais.

The occlusal rehabilitation of partially edentulous patients with reduced vertical dimension of occlusion (VDO) represents a great challenge for the dentist. Normally, involving complex, time-consuming and expensive procedures. The removable partial denture (RPD) overlay type represents a rehabilitative alternative that can be used for this purpose. Through the report of a case, this study aimed to describe the use of the RPD overlay technique as well as discuss the clinical feasibility and effectiveness of this treatment modality. In this case, diagnosed the VDO reduction, initially, the oral rehabilitation was made provisionally, using provisory overlay RPD on the upper arch and conventional provisory RPD in the lower arch. The restoration of mandibular positions made possible the reconstruction of the worn anterior teeth with composite resin and the production of the overlay RPD with metallic covering as the "definitive" treatment. The covering RPDs (overlays) are an excellent and efficient alternative on the restoration of the maxillomandibular relations. They are less costly procedures than conventional fixed procedures, normally used in the rehabilitation of patients with decreased VDO, more conservative and well suited for patients who had wear due parafunctions habits.

Esthetic rehabilitation with minimally invasive feldspathic ceramic veneers: 30 months of clinical follow-up / Reabilitação estética com facetas em cerâmicas feldspáticas minimamente invasivas: 30 meses de acompanhamento clínico

Diastemas among maxillary incisors and gingival contour disharmony are common findings among patients in dental practice. Ceramic veneers are indicated for esthetic rehabilitation of anterior diastemas due their predictable results, optical characteristics, fracture resistance and tooth structure conservation. However, because it is a friable material and have a brittle behavior, fractures occurrences are related to trauma, oclusal overload, parafunctional habits and material fatigue. This article describes 30 months follow-up of an esthetic and functional rehabilitation diastemas closure using feldspathic veneers associated with periodontal surgery and a ceramic repair with composite resin. Gingivectomy and frenectomy needs were found and the surgical procedures performed guided by new anatomic aspects of the crowns. Mock-up was performed after waxing and reverse planning. All anterior teeth underwent minimally invasive preparation. Feldspathic ceramic veneers were made, tried using try in paste and luted with light-cure resin cement. After 24 months, a fracture occurred on the right maxillary canine veneer. The ceramic restoration repair was performed with nano-hybrid composite resin, after the conditioning with 5% hydrofluoric acid, 37% phosphoric acid and silane couple agent. The combination between ceramic veneers and gingivectomy enables to obtain conservative treatments and esthetic success. After six months of the repair, resulting 30 months of follow-up, the anterior restorations were aesthetically and functionally satisfactory.

Presença de diastemas entre os incisivos superiores e desarmonia do contorno gengival são achados comuns entre os pacientes atendidos na rotina clínica. Facetas cerâmicas são indicadas para reabilitação estética de diastemas anteriores devido a previsibilidade de resultados, características óticas, resistências à fratura e conservação de estrutura dentária. Entretanto, por este ser um material frágil e apresentar comportamento friável, fraturas podem estar relacionadas a episódios de trauma, sobrecarga oclusal, hábitos parafuncionais e fadiga do material. Este artigo descreve um acompanhamento clínico de 30 meses de reabilitação estética e funcional de fechamento de diastema utilizando facetas minimamente invasivas confeccionadas com cerâmicas feldspáticas associadas à cirurgia periodontal e necessidade de reparo da cerâmica com resina composta. A indicação de plastia gengival e frenectomia foram constatadas e o procedimento cirúrgico guiado pelo planejamento da nova anatomia das coroas dentárias. Todos os dentes anteriores superiores foram minimamente preparados. O mock-up foi realizado depois do enceramento e do planejamento reverso. Facetas em cerâmicas feldspáticas foram confeccionadas, a cor do cimento resinoso selecionada com pastas testes e a cimentação concluída com cimento de polimerização exclusiva física. Depois de 24 meses de acompanhamento, ocorreu fratura da faceta do canino superior direito. O reparo da restauração cerâmica foi realizado com resina nanohibrida, depois da cerâmica condicionada com ácido fluorídrico 5%, ácido fosfórico 37% e aplicação de agente de união silano. A combinação entre facetas cerâmicas e cirurgia de plastia gengival permite alcançar tratamento conservador e sucesso estético. Posteriormente seis meses do reparo, resultando em 30 meses de acompanhamento clínico, as restaurações anteriores permaneciam estética e funcionalmente satisfatórias.

Analysis of bleaching products associated with desensitizing agents in experimental whitening gel ­randomized clinical trial / Análise de produtos clareadores associados com agentes dessensibilizantes em gel clareador experimental ­ ensaio clínico randomizado

The objective of this clinical study was to determine the effect of adding desensitizing agents in homemade experimental whitening gel Carbamide peroxide 16%. 60 young patients were selected (between 18-28 years), who used randomly (by lottery) the whitening gel DA (with desensitizing agent) or whitening gel CO (without desensitizing agent) characterized as control of a double-blind study, ie the patient and the evaluator did not know the product that was being used. Teeth 15, 14, 13, 12, 11, 21, 22, 23, 24 and 25 were bleached. The guidelines of how to apply the bleaching agents were performed by an experienced and calibrated team, and the application accompanied by examiners in several phases. To measure the color we used a Visual Range Vita Classical through visual inspection by the evaluators and patient information. A comparative test regarding each individual stimulation caused by mechanical attrition and thermal probe with clinical test was done (air syringe) in order to verify the presence of sensitivity in three phases: before treatment, after 7 and 14 days. Data were collected using Visual Analogue Scale (VAS) adapted to four criteria: no pain, mild pain, moderate pain and severe pain. The correlation of the data x teeth sensitivity were obtained separately, and tabulated for further comparative analysis. The results showed that there was no difference between the groups in terms of bleaching effect. In the post-operative sensitivity test, the subjects who used the product without desensitizing showed higher levels of sensitivity in different types of teeth, regardless of sex or age. It was concluded that the addition of desensitizing agent in the carbamide peroxide 16% whitening gel produced less post-bleaching sensitivity index. We emphasize that from the teeth evaluated, the premolars showed higher sensitivity index, followed by the canines and incisors. There was no difference in the bleaching capacity of the products used, demonstrating that the addition of desensitizing did not affect the efficacy of the treatment.

O objetivo deste estudo clínico foi determinar o efeito da adição de agentes dessensibilizantes em gel clareador experimental caseiro Peróxido de Carbamida 16%. Foram selecionados 60 pacientes jovens (entre 18 a 28 anos), que utilizaram aleatoriamente (através de sorteio) o gel clareador DA (com dessensibilizante) gel clareador CO (sem dessensibilizante), caracterizado como grupo controle de um estudo duplo-cego, ou seja o paciente e o avaliador não conheciam o produto que estava sendo utilizado. Foram clareados os dentes 15, 14, 13, 12, 11, 21, 22, 23, 24 e 25. As orientações de como aplicar os agentes clareadores foram realizadas por uma equipe experiente e calibrada, e a aplicação acompanhada por examinadores em diversas fases. Para mensuração da cor foi utilizada uma Escala Visual Vita Clássica através de inspeção visual pelos avaliadores e informações dos pacientes. Foi feito um teste comparativo considerando cada estímulo individualmente provocado por atrito mecânico com sonda clínica e teste térmico (seringa de ar), a fim de verificar a presença de sensibilidade em três fases: antes do tratamento, após 7 e 14 dias. Os dados foram coletados utilizando Escala Visual Analógica (EVA) adaptada a quatro critérios: ausência de dor, dor leve, dor moderada e dor intensa. A correlação dos dados dentes x sensibilidade foram obtidos separadamente, e tabulados para posterior análise comparativa. Os resultados demonstraram que não existiu diferença entre os grupos em termos de efeito clareador. Já no teste de sensibilidade pós-operatória, os sujeitos que utilizaram o produto sem o dessensibilizante mostraram maiores níveis de sensibildade, em diferentes tipos de dentes, independente de gênero ou idade. Pode-se concluir que a adição do agente dessensibilizante no gel clareador peróxido de carbamida 16% gerou menor índice de sensibilidade pósclareamento. Destacamos que dentre os dentes avaliados, os pré-molares apresentaram maior índice de sensibilidade, seguido pelos caninos e incisivos. Não houve diferença na capacidade de clareamento dos produtos empregados, demonstrando que a adição do dessensibilizante não comprometeu a eficácia do tratamento.