Performance of low shrinkage Bis-EFMA based bulk-fill dental resin composites.

OBJECTIVES: The purpose of this study was evaluating the performance of new Bis-EFMA based bulk-fill composites with common methacrylate based composites and commercial dental composites. METHODS: The Bis-EFMA monomer was synthesized and the novel Bis-EFMA based bulk-fill composites were prepared. The resin composite samples were co-cultured with human gingival epithelial cells and human dental pulp stem cells to test the biocompatibility. The edge adaptation was observed under a combination of stereoscope and scanning electron microscope. The internal hardness was measured using a Vickers microhardness tester after one-time filling of cavities prepared in extracted teeth. After friction and wear test on the surface of the resin composites, the surface morphology and volume wear of each group were measured by the optical profilometer. The color stability was measured by a colorimeter. RESULTS: Direct contact with human gingival epithelial cells and human dental pulp stem cells did not cause significant changes in their growth density and morphology, indicating good biocompatibility of Bis-EFMA group (p > 0.05). The continuous margin proportion of the Bis-EFMA group was as good as commercial bulk-fill composites (p > 0.05). The sectional microhardness results showed that the Bis-EFMA group had the highest microhardness. After the friction and wear test, the volume wear of the Bis-EFMA group was minimal, indicating its good wear resistance and mechanical strength. Color changes in all resin groups after 28 days of immersion were within the clinically acceptable range. SIGNIFICANCE: The addition of Bis-EFMA demonstrated excellent biocompatibility, edge adaptation and color stability comparable to commonly used clinical bulk-fill composites, along with preferable mechanical strength, friction and wear resistance. Bis-EFMA based bulk-fill composites have the potential to be employed as a bulk filling material in commercial dental composite applications.

Effect of clinical and laboratory techniques of cementation on the assessment of marginal and internal fit of prosthetic elements

Aim: The aim of this in vitro study was to compare machine and manual cementation of prosthetic elements by measuring internal and marginal fits. Methods: Eighteen anatomic prefabricated abutments were used to manufacture zirconia copings in the Ceramill (n=9) and Lava systems (n=9). The copings were cemented with a fluid consistency addition silicone using a machine (n=18) and manually (n=18) according to the replica technique. They were then cut in the buccal-palatal and mesial-distal directions. The film thickness was photographed using an optical microscope and measured in the internal and marginal regions. The data collected were analyzed by repeated measures ANOVA and Bonferroni's multiple comparison test (∂=.05). The Bland-Altman test was performed to evaluate the agreement between the methods. Results: In the evaluation of the internal and marginal misfits, the mean values observed for the cementation performed with the aid of a machine and manually, were as follows: angular regions, 76.7 µm and 76.2 µm; linear regions, 60.6 µm and 60.7 µm; incisal region, 144.8 µm and 145.2 µm; marginal region, 40.1 µm and 40.2 µm; and overall mean, 80.4 µm and 80.6 µm, respectively. No significant differences were found between the 2 methods, for any of regions and systems (P>.05). The Bland-Altman test showed agreement between the methods (P>.05) and that the limits of agreement found were clinically acceptable. Conclusions: Within the limitations of this in vitro study, we can conclude that cementation using manual techniques or mechanical aid produces the same cement films

The effect of aging on the accuracy of marginal adaptation and fracture resistance of CAD/CAM PEEK single crown restoration

Aim: In recent years, great advances have been made in the use of CAD/CAM to prepare fixed restorations. The marginal and internal fit of these restorations is a principal determinant for their clinical success. In addition, the nature of the oral environment affects the mechanical properties of these restorations. Therefore, this study aimed to investigate the effect of aging process under conditions that simulate the oral environment on the marginal adaptation, and, fracture resistance of crowns fabricated from polyether ether ketone (PEEK) using CAD/CAM methods. Methods: Twenty identical crown restorations were fabricated by using CAD/CAM methods to mill polyether ether ketone (PEEK) material. These crowns were produced by using a software design of an epoxy resin replica of the prepared maxillary first premolar tooth. All PEEK crowns were cemented and randomly divided into two equal groups (A, B). Each group was divided into subgroups (A1, A2 and B1, B2). Group A1 and A2 were used to measure marginal adaptation and fracture resistance, respectively, before aging, while group (B1 and B2) were measured after aging. The cemented crowns were mounted in resin molds to facilitate the sectioning process. The measurements of the marginal gap were performed after sectioning at four points using a stereomicroscope. The fracture resistance of the crowns was investigated using a universal testing machine. A statistical analysis was performed using the GraphPad Prism® software version and unpaired Student's t-test. Results: The results revealed that aging affected the marginal gap, and the fracture resistance of the PEEK crowns. While aging, negatively affected the conditions under investigation, however the least significant difference of marginal gap was found in the margin region. Conclusions: PEEK-CAD/CAM is considered as a good alternative prosthodontic material for fixed prostheses. The CAD/CAM technique used to make PEEK crown restorations in our study offers the advantages of high marginal accuracy and fracture resistance for long-term performance in the oral environment

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)

Adaptación marginal e interna de cofias fabricadas por métodos convencionales, CAD/CAM de fresado y sinterizado por láser / Marginal and internal adaptation of copings manufactured by conventional methods, CAD/CAM milling and laser sintering

Introducción: la adaptación marginal e interna de nuestras restauraciones fabricadas por fundición sistemas de fresado y sinterización láser es uno de los factores clínicos más importantes para el éxito de las prótesis fijas, previniendo el riesgo de microfiltración y enfermedad periodontal. Objetivo: evaluar la adaptación marginal e interna de cofias metálicas en aleación Cr-Co confeccionadas por técnicas convencionales, CAD/ CAM de fresado y sinterizado por láser. Material y métodos: estudio de tipo experimental, comparativo e in vitro. Se imprimió un modelo maestro en Cr-Co, proveniente del escaneo de un premolar preparado para corona completa, sobre el cual se diseñaron 30 cofias divididas en tres grupos: el primero que corresponde al grupo cofias fundidas fresadas en disco de cera A (A = 10), el segundo grupo cofias fresadas en disco de metal presinterizado B (B = 10) y el tercer grupo cofias impresas por sinterización láser C (C = 10). Se empleó la réplica de silicona, colocando silicona al interior de cada cofia, sobre el modelo maestro, simulando al cemento, mediante una máquina de ensayo universal se realizó una compresión de 50 N. Luego de retirar cada cofia se rellenaron con silicona pesada de adición, obteniendo una réplica de silicona. Se efectuaron dos cortes transversales en sentido vestíbulolingual y mesiodistal. Se observó el espesor de silicona VPS (vinil poliéter silicona) mediante un estereomicroscopio (Nikon SMZ745T), obteniendo valores en micrómetros. Para el análisis estadístico se utilizó el software SPSS 25 con el fin de realizar la prueba de normalidad y ANOVA de dos vías bajo un nivel de confianza del 95%. Resultados: el menor gap lo obtuvo el grupo de fresadas, seguido de las impresas y por último las fundidas por métodos convencionales. ANOVA de dos vías reveló diferencias estadísticamente significativas entre los tres grupos (p < 0.0001). Conclusiones: se encontró que el gap varía con cada método de fabricación, la técnica convencional de fundido mostró un mayor gap, ninguna excediendo el rango clínicamente aceptable (AU)

Introduction: the marginal and internal adaptation of our restorations manufactured by casting, milling systems and laser sintering is one of the most important clinical factors for the success of fixed prostheses, preventing the risk of microleakage and periodontal disease. Objective: evaluate the marginal and internal adaptation of metal copings in Cr-Co alloy made by conventional techniques, CAD/CAM milling and laser sintering. Material and methods: an experimental, comparative and in vitro study, a Cr-Co master model was printed from the scan of a premolar prepared for a full crown. An experimental, comparative and in vitro study, a Cr-Co master model was printed from the scan of a premolar prepared for a full crown, on which 30 caps divided into three groups were designed; the first group corresponds to the cast copings milled on a wax disc A (A = 10), the second group milled copings on a presintered metal disc B (B = 10) and the third group printed by laser sintering copings C (C = 10). The silicone replica was used, placing silicone inside each coping, on the master model, simulating cement, using a universal testing machine, a 50 N compression was performed. After removing each coping, they were filled with heavy addition silicone, obtaining a silicone replica. Two cross-sections were made in the buccolingual and mesiodistal direction., observing the thickness of the VPS (vinyl polyeter silicone) silicone using a stereomicroscope (Nikon SMZ745T), obtaining values in micrometers. For the statistical analysis, the SPSS 25 software was used in order to perform the normality and two-way ANOVA tests under a 95% confidence level. Results: the smallest gap was obtained by the milled group, followed by the printed ones and finally those cast by conventional methods. Two-way ANOVA revealed statistically significant differences between the three groups (p < 0.0001). Conclusions: the gap was found to vary with each fabrication method, the conventional casting technique showed a larger gap, none exceeding the clinically acceptable range (AU)

Comparative evaluation of internal fit and marginal gap of endocrowns using lithium disilicate and polyether ether ketone materials - an in vitro study.

BACKGROUND: The aim of the study was to investigate the effect of material and occlusal preparation design on the internal fit and marginal gap of endocrowns made of Polyether ether ketone (PEEK) and lithium disilicate. METHODS: 32 endocrowns were fabricated on prepared mandibular molars and divided into two groups (n = 16) according to the material. Group L: lithium disilicate and Group P: PEEK. Each group was further subdivided into two subgroups (n = 8) according to the occlusal preparation design: full occlusal coverage (LF and PF) and partial occlusal coverage (LP and PP). Samples were analyzed using microcomputed tomography (µCT) with a voxel size of 6 µm to evaluate internal fit, and an optical microscope was used to evaluate the marginal gap. Data were collected, tabulated, and statistically analyzed. Numerical data were described as mean and standard deviation and compared using the ANOVA test. The level of significance was set at α P ≤ 0.05. RESULTS: All groups' internal fit and marginal gaps values were within the acceptable clinical range. However, the lithium disilicates group recorded statistically significantly higher mean internal gap values than the PEEK groups. Regardless of the material, the difference between the two occlusal designs was not statistically significant in both internal fit and marginal gap records. CONCLUSION: Within the limitations of this study, PEEK endocrown restorations revealed better internal fit and marginal gap than lithium disilicate endocrown restorations. The marginal and internal fit of both lithium disilicate and PEEK endocrown restorations were within the clinically acceptable range. The occlusal preparation design had no influence on the internal fit and marginal gap of the endocrown restoration.

Evaluation of a novel restorative protocol to treat non-carious cervical lesion associated with gingival recession: a 2-year follow-up randomized clinical trial.

OBJECTIVE: To compare 2 different resin composites and 2 adhesive systems used in a new restorative protocol (partial restoration) to treat non-carious cervical lesions associated with gingival recession type 1 (RT1). MATERIAL AND METHODS: Eighty combined defects (CDs) were treated with a partial restoration and periodontal plastic surgery for root coverage. The CDs were randomly assigned to one of the following groups: NP + TE (n = 20), nanofilled composite and 2-step total-etch adhesive system; NP + UA (n = 20), nanofilled composite and universal adhesive system; MH + TE (n = 20), microhybrid composite and 2-step total-etch adhesive; MH + UA (n = 20), microhybrid composite and universal adhesive. Restorations were assessed using the United States Public Health Service (USPHS) criteria at 1 week (baseline) and 6, 12, and 24 months. Survival rate, periodontal parameters, dentin hypersensitivity (DH), and aesthetics were also evaluated. RESULTS: After 24 months, only the MH + TE group did not lose any restoration, with no significant differences between groups. For surface roughness parameter, MH presented 83.3% of the restorations scoring Bravo, whereas NP presented 48.5% of the restorations scoring Bravo. All groups presented restorations with marginal discoloration. All periodontal parameters behaved similarly, regardless of the restorative material. All groups presented significant reductions of dentin hypersensitivity and improved aesthetic perceptions (p < 0.05). CONCLUSION: Both resin composites and adhesives tested can be combined for partial restorations to treat CDs. CLINICAL RELEVANCE: This new restorative-surgical protocol to treat CDs presents satisfactory outcomes. The partial restorations can be successfully executed with both combinations of adhesives and resin composites evaluated in this investigation. TRN : ClinicalTrial.gov: NCT03215615; registration date July 12, 2017.

Influence of marginal incision and Le Fort I osteotomy on periodontal tissues: a prospective longitudinal study.

The purpose of this prospective study was to evaluate whether the surgical protocol involving marginal incision and Le Fort I osteotomy affects the periodontal outcome. Twenty-nine patients requiring surgical correction of maxillary dysgnathia were selected for this study. Periodontal conditions of maxillary anterior teeth were assessed prior to the surgery (T0), one month (T1), and 6 months (T2) after the surgical procedure. Interdental papillae loss, periodontal parameters and aesthetic outcomes in the anterior zone were assessed. Statistical analysis was performed with Friedman´s test and within ANOVA (p ≤ 0.05) followed by post-hoc tests. Papilla height decreased from T0 to T1 (p = 0.003), followed by an increase from T1 to T2 (p = 0.040). PPD (T0 = 1.72 ± 0.46; T2 = 2.13 ± 0.43) and CAL (T0 = 1.24 ± 0.55; T2 = 1.99 ± 0.70) increased after 6 months. There were statistically significant differences in aesthetic score among T0, T1 and T2. Periodontal changes after orthognathic surgery were within acceptable biological levels. Although a change in papillae height was reported after the surgery, initial values were recovered after 6 months. Surgical incision design might improve the outcome of Le-Fort I osteotomy. Anterior aesthetic zone may benefit from a marginal incision design, as it respects vascularization principle and may ensure a wound healing without complications.

The Effect of Immediate Dentin Sealing on the Marginal Adaptation of LithiumDisilicate Overlay Restorations using different types of luting agents / Efeito do selamento imediato da dentina na adaptação marginal de restaurações overlay de dissilicato de lítio utilizando diferentes tipos de agentes de cimentação: estudo in vitro

Objective:This study evaluated the effect of immediate dentin sealing on the marginal adaptation of lithium disilicate overlays with three different types of resin-luting agents: preheated composite, dual-cure adhesive resin, and flowable composite. Materials and Methods: Forty-eight maxillary first premolars of similar size were prepared with a butt joint preparation design. The teeth were separated into two primary groups, each with twenty-four teeth: Group DDS: Delay dentin sealing (non-IDS) teeth were not treated. Group IDS: dentin sealing was applied immediately after teeth preparation. Each group was subsequently separated into three separate subgroups. Subgroups (DDS+Phc, IDS+Phc): cemented with preheated composite (Enamel plus HRi, Micerium, Italy), Subgroups (DDS+Dcrs, IDS+Dcrs): cemented with dual-cured resin cement (RelyX Ultimate, 3M ESPE, Germany) and Subgroups (DDS+Fc, IDS+Fc): Cemented with flowable composite (Filtek supreme flowable, 3M ESPE, USA). Using a digital microscope with a magnification of 230x, the marginal gap was measured before and after cementation at four different locations from each surface of the tooth, and the mean of measurements was calculated and analyzed statistically using the independent t-test, one-way ANOVA test, Bonferroni correction at a significance level of 0.05. Results: The samples that were immediately sealed with dentin bonding agent showed lower marginal gaps than delayed dentin sealing, both pre-and post-cementation for all subgroups, with a statistically significant difference (p˂0.01). The marginal gap was significantly lower in the IDS+Fc (48.888 ±5.5 µm) followed by the IDS+Dcrs group (53.612 ±5.8 µm) and IDS+Phc (79.19 9±6.9 µm) respectively, while the largest marginal gaps were observed in the DDS+Phc group (86.505 ±5.4 µm). Conclusion: Generally, the teeth with IDS showed better marginal adaptation than teeth without IDS. The marginal gap was smaller with flowable composite and dual-cure resin cement than with preheated composite (AU)

Objetivo:Esse estudo avaliou o efeito do selamento imediato da dentina na adaptação marginal de overlays em dissilicato de lítio com três tipos diferentes de agentes de cimentação resinosos: resina composta pré-aquecida, adesivo resinoso dual e resina fluida. Materiais e métodos: Quarenta e oito primeiros pré-molares maxilares com tamanho similar foram preparados com término em ombro. O dente foi separado em dois grupos primários, cada um com vinte e quatro dentes: Grupo DDS: retardado selamento da dentina (non-IDS) dente não foi tratado. Grupo IDS: selamento dentinário foi aplicado imediatamente após a preparação do dente. Cada grupo foi separado de modo subsequente em três subgrupos. Subgrupo (DDS+Phc, IDS+Phc): cimentado com resina pré-aquecida (Enamel plus HRi, Micerium, Italy), Subgrupo (DDS+Dcrs, IDS+Dcrs): cimentado com cimento resinoso dual (RelyX Ultimate, 3M ESPE, Germany) e Subgrupo (DDS+Fc, IDS+Fc): cimentado com resina fluida (Filtek supreme flowable, 3M ESPE, USA). Usando um microscópio digital com magnificação de 230x, o gap marginal foi medido antes e após a cimentação em quatro diferentes localizações de cada superfície do dente e a média das medidas foi calculada e estatisticamente analisada através do uso do teste ANOVA um-fator e teste independente de Tukey e correção Bonferroni com nível de significância de 0,05. Resultado: As amostras que foram imediatamente seladas com agente adesivo dentinário apresentaram menores gaps marginais do que o selamento dentinário retardado, ambos pré e pós cimentação para todos os subgrupos apresentaram diferença estatística significante (p˂0.01). O gap marginal foi significativamente menor para IDS+Fc (48.888 ±5.5 µm) acompanhado do IDS+Dcrs group (53.612 ±5.8 µm) e IDS+Phc (79.19 9 ±6.9 µm) respectividamente, enquanto o maior gap marginal foi observado no grupo DDS+Phc (86.505 ±5.4 µm). Conclusão:Geralmente, o dente com IDS apresentou melhor adaptação marginal do que o dente sem IDS. O gap marginal foi menor com resina fluida e cimento resinoso dual do que com a resina composta pré-aquecida (AU)

Evaluating the Marginal and Internal Discrepancy of Nickel-Chrome Copings Made on Fixed Partial Denture Implants with Conventional and 3D Printing Techniques.

AIM: This study aimed to evaluate the marginal and internal discrepancy of nickel-chrome (Ni-Cr) copings made on implant bridges with conventional and 3D printing techniques. MATERIALS AND METHODS: 30 three-unit Ni-Cr FDPs (60 copings) were made by 3D-printing technique (PolyJet group), lost-wax method with die spacer technique (die spacer group), and lost-wax method with burn-out the cap (burn-out cap group). Then, the frames obtained from the three methods were checked to examine the marginal discrepancy by stereomicroscope after preparation and polishing. The silicon replica method was used to investigate the internal discrepancy at 6 points (buccal portion of occlusal surface, lingual portion of occlusal surface, middle area of the axial surface in the lingual, middle area of the axial surface in the buccal, cervico-buccal area, and cervico-lingual area). Kolmogorov-Smirnov test was performed first to estimate the normality of data distribution. A one-way ANOVA and post hoc Tukey test were done for comparing marginal and internal discrepancies between groups. The significant level was considered p < 0.05. RESULTS: The mean ± standard deviation of marginal discrepancy in the PolyJet group, die spacer group, and burn-out cap group was 37.9 ± 15, 68.8 ± 31.8 and 42.7 ± 3.6 µm for buccal margins and 40.4 ± 12.3, 64 ± 21.7, and 42.4 ± 2.1 µm for lingual margins, respectively. The means of buccal and lingual marginal discrepancy in the burn-out cap group and PolyJet group were significantly lower than the die spacer group (p < 0.001). Marginal discrepancy was not statistically different between the burn-out cap group and the PolyJet group. The mean ± standard deviation of overall internal discrepancy in the PolyJet group, die spacer group, and burn-out cap group was 64.6 ± 3.7, 72 ± 22.2, and 58.7 ± 2 µm, respectively. There was a significant difference between the mean of internal discrepancy between three groups (p = 0.001). The mean of internal discrepancy of the burn-out cap group was significantly lower than the die spacer group (p = 0.001) and PolyJet group (p = 0.005). Internal discrepancy was not significantly different between the PolyJet group and the die spacer group (p = 0.168). CONCLUSION: The marginal and internal gap rates of the three groups were within clinically acceptable limits. The 3D printing technique and lost-wax method with burn-out the cap had the lowest buccal and lingual marginal discrepancies. The burn-out cap method had better fitness and less internal discrepancy than 3D printing and die spacer groups. CLINICAL SIGNIFICANCE: Lower marginal discrepancy of copings fabricated by using 3D printed patterns may improve clinical success of implant restoration. How to cite this article: Ziaei M, Bajoghli F, Sabouhi M, et al. Evaluating the Marginal and Internal Discrepancy of Nickel-Chrome Copings Made on Fixed Partial Denture Implants with Conventional and 3D Printing Techniques. J Contemp Dent Pract 2023;24(11):826-833.

Influence of restorative materials on occlusal and internal adaptation of CAD-CAM inlays

Aim: To evaluate the occlusal and internal marginal adaptation of inlay restorations made of different materials, using CAD-CAM. Methods: Preparations were made for MOD inlays of one-third intercuspal width and 4 mm depth in 30 third human molars. The teeth were restored using CAD-CAM materials (n=10) of nanoceramic resin (Lava Ultimate), polymer-infiltrated ceramic network (VITA ENAMIC), or lithium disilicate glass-ceramic (IPS e.max CAD). The specimens were cemented with dual resin cement and sectioned at the center of the restoration, after which the two halves were evaluated, and photographed The occlusal and internal discrepancy (µm) was determined at five points: cavosurface angle of the occlusal-facial wall (CA-O); center of the facial wall (FW); faciopulpal angle (FPA); center of the pulpal wall (PW); and center of the lingual wall (LW). The data were submitted to the Kruskal-Wallis and the Dunn tests (α=0.05). Results: No difference was observed among the materials regarding the occlusal discrepancy at the CA-O, FPA, or PW internal points. The e.max CAD measurement at FW showed larger internal discrepancy than that of Lava (p=0.02). The internal discrepancy at LW was greater for e.max CAD than VITA ENAMIC (p=0.02). Conclusion: Lithium disilicate glass-ceramic presented greater internal discrepancy in relation to the surrounding walls of the inlay preparations

Fit of metal-ceramic crowns: effect of coping fabrication method and veneering ceramic application

Aim: To evaluate the influence of cobalt-chromium (Co-Cr) coping fabrication methods and ceramic application on the marginal and internal fit of metal-ceramic crowns. Methods: Co-Cr copings for metal-ceramic crowns were prepared by lost wax casting or CAD-CAM machining of sintered blocks. The fit was analyzed using the silicone replica technique at four assessment points: marginal gap (MG), axial wall (AW), axio-occlusal (AO) angle, and central occlusal (CO) wall. After the initial analysis, the copings were ceramic-veneered with the layering technique, and the fit was again determined. Data were statistically analyzed by paired and unpaired Student's-t test (α=0.05). Results: Marginal and internal fit before ceramic application according to the coping manufacturing method showed significant differences only at CO (p < 0.001), with milled copings (137.98±16.71 µm) showing higher gap values than cast copings (112.86±8.57 µm). For cast copings, there were significant differences at MG (before 109.13±8.79 µm; after 102.78±7.18 µm) and CO (before 112.86±8.57 µm; after 104.07±10.63 µm) when comparing the fit before and after ceramic firing. For milled copings, there was significant difference only at AO (before 116.39±9.64 µm; after 108.54±9.26 µm). Conclusion: This study demonstrated that the coping fabrication method influenced the internal fit. Ceramic firing maintained or improved the fit of the metal-ceramic crowns. The marginal discrepancy of all restorations, before and after ceramic firing, can be considered clinically acceptable

The Effect of Radiotherapy on the Marginal Adaptation of Class II Direct Resin Composite Restorations: A Micro-computed Tomography Analysis.

This laboratory study was designed to evaluate the marginal adaptation of Class II mesio-occlusodistal (MOD) restorations at the cervical region with micro-computed tomography (micro-CT). Two groups of restorations were compared: 1) those that had been exposed to radiotherapy before restoration was performed using a universal adhesive in etch-and-rinse and self-etch modes; and 2) those that had previously been restored using a universal adhesive in etch-and-rinse and self-etch modes and had subsequently undergone radiotherapy. Sixty intact human molars were randomly divided into groups according to irradiation status: no radiotherapy (control group); radiotherapy followed by restoration (radiotherapy-first group); and restoration followed by radiotherapy (restoration-first group). These three groups were then subdivided into two groups each on the basis of adhesive application type (etch-and-rinse and self-etch modes), for a total of six groups (n=10/group). Standardized Class II MOD cavities were prepared. A universal adhesive (Clearfil Universal Bond Quick, Kuraray, Okayama, Japan) was applied. The teeth were restored with resin composite (Estelite Posterior Quick, Tokuyama, Tokyo, Japan). The radiotherapy protocol was conducted with 60 gray (Gy) at 2 Gy/day, five days a week for six weeks. Adhesive defects were analyzed in distal and mesial views and evaluated with micro-CT (SkyScan 1174v2, Kontich, Antwerp, Belgium) on the basis of the volume of black spaces between the cavity walls and the restorative materials (mm3). The data were analyzed using the Kruskal-Wallis, Mann Whitney U and Wilcoxon tests (p<0.05). The radiotherapy protocol did not affect the marginal adaptation of the universal adhesive at the cervical regions. Regarding the application modes, for the radiotherapy-first group, the self-etch mode caused significantly higher adhesive defects than the etch-and-rinse mode at the dentin margin. For the no-radiotherapy group, the adhesive defects at the dentin margin were significantly higher than at the enamel margin with the application of the etch-and-rinse mode.

Internal Adaptation and Marginal Accuracy of Two Different Techniques-based Poly (ether ether ketone) Single Crowns: An In Vitro Study.

PURPOSE: The goal of this study was to evaluate how different fabrication techniques affected the marginal accuracy and internal adaptability of poly (ether ether ketone) (PEEK) molar single crowns. MATERIALS AND METHODS: Twenty PEEK crowns were constructed using two different fabrication techniques, and they were divided into two main groups (PEEK-CAD and PEEK-pressed). PEEK-CAD crowns were numbered from 1 to 10. PEEK-pressed crowns were numbered from 11 to 20. Each group had 10 PEEK crowns, and both were constructed over a master die. For internal fit measurements, silicone replica bodies were built and cut into two halves buccolingually. Marginal accuracy was measured using three evenly spaced landmarks along the specimen's cervical circumference on each surface using a Leica L2 APO* microscope. RESULTS: In terms of marginal accuracy, the Press group had a statistically significant greater mean marginal gap value than the computer aided-designing (CAD) group. While in terms of internal fit, there was no statistically significant difference in internal fit between the CAD and Press groups. At a significance level of two-tailed p-value = 0.21 (p > 0.05). CONCLUSION: PEEK-CAD crowns demonstrated higher marginal accuracy and nearly similar internal fit when compared to PEEK-pressed crowns. CLINICAL SIGNIFICANCE: PEEK material could be used as a substitute for zirconia for a full coverage posterior restoration.

Impact of head and neck radiotherapy on the longevity of dental adhesive restorations: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Established restorative protocols for patients after head and neck radiotherapy are lacking, increasing the failure rates of dental adhesive restorations. PURPOSE: The purpose of this systematic review and meta-analysis was to analyze the evidence regarding the impact of head and neck radiotherapy on the longevity of dental adhesive restorations. MATERIAL AND METHODS: A search was performed using PubMed, Scopus, and Embase in May 2018 (updated in November 2020). Data extraction was performed regarding the percentage of restoration failure among dental adhesive materials, including glass ionomer cements, resin-modified glass ionomer cements, and composite resins. Risk of bias was assessed by the meta-analysis of statistics assessment and review instrument (MAStARI). Confidence in cumulative evidence was evaluated by the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) protocol. RESULTS: Four studies met the inclusion criteria. All included studies were classified as having a moderate risk of bias and reported results regarding class V restorations. Overall, composite resins presented lower failure rates at 2 years (30%) when compared with resin-modified glass ionomer (41%) and glass ionomer cements (57%). Meta-analysis showed that the risk of failure with glass ionomer cements was greater than with resin-modified glass ionomer cements (RR: 1.71, P<.001). Composite resins presented lower risk of failure when compared with glass ionomer (RR: 2.29, P<.001) and resin-modified glass ionomer cements (RR: 1.30, P=.03). Three studies reported results regarding fluoride compliance, which had a negative effect on the survival rates of glass ionomer and resin-modified glass ionomer cements and a positive effect on composite resin restorations. CONCLUSIONS: The results suggest that composite resin restorations associated with fluoride gel compliance seems to be the best alternative for restoring class V lesions in patients after head and neck radiotherapy. However, the results showed moderate certainty of evidence, which justifies the need for more randomized clinical trials regarding this subject.

In Vitro Microscopic Evaluation of Metal- And Zirconium-Oxide-Based Crowns' Marginal Fit

ABSTRACT Objective To evaluate the marginal adaptation of computer-aided designing and computer-aided machining (CAD/CAM) fabricated cobalt-chromium and zirconium-oxide-based ceramic crowns compared to those produced by a conventional method. Material and Methods The study consists of three groups; 45 crowns fabricated from cobalt-chromium (CAD-CoCr) and 45 crowns manufactured from zirconium CAD/CAM technology (CAD-Z), and 45 control (C) which consists of conventional metal-ceramic crowns. The marginal discrepancies in vertical dimensions were assessed utilizing a microscope in four surfaces (mesial, distal, vestibular, and oral) for each crown. On completion of the microscopic evaluation, multivariate analysis of variance (MANOVA) was used to study the difference in the four surfaces, considered altogether. Two-way ANOVA revealed the effect of three systems used for gap measurements of each landmark. The differences observed were considered significant at p<0.05. Results There were no differences in the four surfaces revealed by АNOVА in the three groups when considered altogether. Two-way ANOVA of each surface discovered no differences among all groups as well. Conclusion The CAD/CAM crowns revealed a comparable and satisfactory marginal adaptation compared to conventional metal-ceramic crowns.

Effect of Light-Curing Unit Type and Bulk-Fill Composite Resins with Different Photoinitiators on Marginal Gaps of Class II Restorations

Abstract Objective: To evaluate the effect of two types of light-curing units (second and third generations) and two types of bulk-fill composite resins with different photoinitiators - Tetric N-Ceram Bulk Fill (TNCB) and Xtra Fil (XTF) on gap formation at the gingival margins of Cl II restorations. Material and Methods: Fifty-six standard Cl II cavities were prepared on the mesial and distal surfaces of premolar teeth, with the gingival margin of the cavities 1 mm apical to the CEJ. The samples were randomly assigned to two groups based on the composite resin type and two subgroups based on the light-curing unit type and restored. After 5000 rounds of thermocycling, gingival margin gap in each sample was measured in µm under an electron microscope at ×2000 magnification. Data were analyzed by two-way ANOVA and Tukey tests (α=0.05). Results: Marginal gaps of TNCB composite resin were significantly smaller than those of XTF composite resin (p<0.001). There were no significant differences between the two light-curing units in each group (p=0.887 with XTF and p=0.999 with TNCB). Conclusion: The gaps at gingival margins of Cl II cavities with TNCB bulk-fill composite were smaller than XTF composite resin. Both composite resins can be cured with both the second- and third-generation LEDs (AU).

Do Bulk-Fill Resin Composites Present More Susceptibility to Marginal Degradation in Different Clinical Scenarios? A Systematic Review and Meta-Analysis

Abstract Objective: To compare the marginal degradation (susceptibility to marginal adaptation and marginal discoloration) of composite restorations placed in class II and V cavities using conventional and bulk-fill resin composites. Material and Methods: This study was approved by PROSPERO database (#42020201596). PubMed, Scopus, Embase, Web of Science, Lilacs, Cochrane, Open Grey, Clinical Trials, and Rebec databases were searched by three independent investigators using MeSH terms, supplementary concepts, synonyms, and free keywords, based on the PICOS strategy (P, population: restoration in permanent teeth; I, intervention: bulk-fill resin composite; C, comparison: conventional resin composite; O, outcome: marginal discoloration and adaptation; and S, study design: randomized and non-randomized clinical trials). The risk of bias was evaluated according to the Cochrane Collaboration's tool, the meta-analyses by RevMan software, the certainty of evidence by the Grading of Recommendations Assessment, Development, and Evaluation, and the leave-one-out sensitivity test. The prevalence of successful events and the total number of restorations were used to calculate the risk difference at a confidence interval of 95%, according to a fixed-effect model. The heterogeneity was evaluated using the I2 index. Results: 16 from 10,780 studies were selected and included for qualitative and quantitative analysis. Two studies were considered as high risk of bias, one showing some concerns, and 13 as low risk of bias. Four meta-analyses evaluated the marginal adaptation and marginal discoloration in class II and V cavities, with a nonsignificant heterogeneity (I2 = 0%, p>0.05). The certainty of evidence was considered high, except for two subgroups of each outcome. Conclusion: There is evidence that composite restorations using conventional and bulk-fill resin composites present similar clinical performance related to marginal degradation (AU).

Evaluation of the marginal adaptation of class II restorations carried out in a Faculty in the State of Espírito Santo / Avaliação da adaptação marginal das restaurações classe II realizadas em uma Faculdade no Estado do Espírito Santo

Introduction: composite resins are materials widely used for Class II restorations, to restore the anatomization of the dental element. However, there are several factors that can interfere with the quality of a good restoration. Objective: the objective of the present study is to carry out a retrospective evaluation of the clinical performance of Class II restorations performed by undergraduate students of Dentistry at the Escola São Francisco de Assis (ESFA), and to identify the main errors. Material and method: we selected the medical records of patients treated in the disciplines of Dentistry II, Integrated I and II in the Dentistry clinic at ESFA, which presented detailed information on the Class II procedure, as well as initial radiographic examinations, using the FDI method. The sample consisted of 33 medical records that included 72 teeth. Result: it was observed that more than 80% of the restorations were classified as acceptable. And, only 19.44% of the restorations were unacceptable, failing due to functional and biological properties. Conclusion: it was found that undergraduate students in Dentistry at ESFA, who are guided by professors to perform treatments following pre-established clinical protocols, are capable of carrying out quality restorative procedures.

Introdução: as resinas compostas são materiais muito utilizados para restaurações Classe II, com função de restabelecer a anatomização do elemento dental. No entanto, diversos são os fatores que podem interferir na qualidade de uma boa restauração. Objetivo: o objetivo do presente estudo é realizar uma avaliação retrospectiva do desempenho clínico de restaurações Classe II executadas por alunos da graduação de Odontologia da Escola São Francisco de Assis (ESFA) e identificar as principais falhas cometidas. Material e método: foram selecionados os prontuários dos pacientes atendidos nas disciplinas de Dentística II, Integrada I e II na clínica de Odontologia da ESFA, que apresentaram as informações detalhadas do procedimento de Classe II, bem como exames radiográficos iniciais, usando o método FDI. A amostra foi composta por 33 prontuários que incluíam 72 dentes. Resultado: observou-se que mais de 80% das restaurações foram classificadas como aceitáveis. Visto que, apenas 19,44% das restaurações estiveram inaceitáveis, pecando para as propriedades funcionais e biológicas. Conclusão: constatou-se que os alunos da graduação em Odontologia da ESFA, os quais são orientados por professores a realizar tratamentos seguindo protocolos clínicos pré-estabelecidos, são capazes de confeccionar procedimentos restauradores de qualidade.

Avaliação do tipo de retenção e o uso de diferentes intermediários na adaptação de próteses unitárias sobre implantes / Evaluation of the type of retention and the use of different abutments in the adaptation of single prostheses on implants

Atualmente, devido a perda do elemento dentário e a procura por um tratamento estético e principalmente funcional, a reabilitação com próteses sobre implante tem sido amplamente empregada, com elevada previsibilidade a longo prazo. Com isso, muito tem sido relatado na literatura acerca das possíveis complicações dessa modalidade de tratamento, principalmente relacionado às possibilidades de falhas mecânicas das próteses implantossuportadas. Por isso, o objetivo do presente projeto foi avaliar a influência na adaptação marginal e interna, da utilização do intermediário protético e do tipo de retenção das próteses (parafusada e cimentada) em implantes cone morse submetidos à ciclagem mecânica. Foram confeccionados 40 corpos de prova, no qual cada um tinha a presença de um implante, com as dimensões de 4mm de diâmetro e 11,5mm de comprimento cone morse (n = 40). Dessa forma, foi avaliado a influência da utilização do intermediário e dos sistemas de retenção em cada conexão de maneira específica. Metade dos corpos de prova de cada sistema de conexão foram confeccionados em UCLA (n=20, sendo 10 parafusadas e 10 cimentadas), enquanto que a outra metade foi utilizado um intermediário pré-fabricado (Pilar Universal (n=20, sendo 10 parafusadas e 10 cimentadas). Os corpos de prova foram submetidos à ciclagem mecânica submersos em água destilada simulando um tempo clínico de cinco anos. Além disso, foram avaliados quanto ao torque e destorque (N) e adaptação marginal e interna (µm) antes e após a ciclagem mecânica. Os dados provenientes das mensurações foram organizados em tabela em formato Excel (Microsoft Office Excel, Redmond, WA, Estados Unidos) e submetidos ao software SigmaPlot (SigmaPlot, San Jose, CA, EUA) versão 12.0. Todos os dados foram analisados inicialmente com a utilização da estatística descritiva. Em seguida, os dados para intrusão (valores positivos), extrusão (valores negativos), destorque inicial, destorque final, e descimentação foram analisados em relação a distribuição de normalidade (teste Shapiro-Wilk e igualdade de variância) e, posteriormente, foi adotada a Análise de Variância (ANOVA) a um fator (Grupos diferentes materiais: G1 a G4), quando houve normalidade dos dados, o pós teste de Tukey foi adotado para as comparações múltiplas, quando não foi identificado uma distribuição normal, empregou-se o teste de Kruskall-Wallis e pós-teste de Dunn's ou Tukey, semelhantemente foi realizada a análise específica das variáveis pilares (UCLA e Pilar Universal) e sistemas de retenção (Parafusado e Cimentado). Para todos os testes aplicou-se nível de significância de 5% (α=0,05). A análise gráfica foi considerada através de um gráfico de barras para os dados que apresentaram normalidade com valores de média e desvio padrão, e as demais análises que não apresentaram normalidade foi considerado a confecção de um boxplot para cada grupo comparativo. As próteses sobre implante utilizando pilares em zircônia tem ganhado cada vez mais espaço, além do estudo in vitro, foi realizada uma revisão sistemática para comparar a perda óssea marginal e as complicações próteticas de reabilitações utilizando pilares de zircônia cimentado e parafusado. Em relação as próteses cimentadas e parafusadas, devido as evidências conflitantes e a presença de muitas revisões sistemáticas sobre o tema, foi realizada uma overview de revisões sistemáticas, com o objetivo de compilar as informações disponiveis e avaliar a qualidade metodologica desses estudos a respeito das complicações presentes nas próteses sobre implante cimentadas ou parafusadas(AU)

Currently, due to the loss of the dental element and the search for an aesthetic and mainly functional treatment, rehabilitation with implant prostheses has been widely used, with high long-term predictability. Thus, much has been reported in the literature about the possible complications of this treatment modality, mainly related to the possibility of mechanical failure of implant-supported prostheses. Therefore, the objective of the present project was to evaluate the influence on the marginal and internal adaptation, the use of the prosthetic intermediate and the type of retention of the prostheses (screwed and cemented) in morse taper implants submitted to mechanical cycling. 40 specimens were made, in which each one had an implant, with dimensions of 4 mm in diameter and 11.5 mm in length (n = 40). In this way, the influence of the use of intermediaries and retention systems in each connection was evaluated in a specific way. Half of the specimens of each connection system were made in UCLA (n=20, being 10 screwed and 10 cemented), while the other half was used a prefabricated intermediate (Universal Abutment (n=20, being 10 screwed) and 10 cemented). The specimens were submitted to mechanical cycling submerged in distilled water simulating a clinical time of five years. In addition, they were evaluated for torque and detorque (N) and marginal and internal adaptation (µm) before and after mechanical cycling. Data from measurements were organized in a table in Excel format (Microsoft Office Excel, Redmond, WA, USA) and submitted to SigmaPlot software (SigmaPlot, San Jose, CA, USA) version 12.0. All data were initially analyzed using descriptive statistics. Then, data for intrusion (positive values), extrusion (negative values), initial detorque, final detorque, and debonding were analyzed in relation to dist determination of normality (Shapiro-Wilk test and equality of variance) and, later, the one-way Analysis of Variance (ANOVA) was adopted (Different material groups: G1 to G4), when there was normality of the data, the Tukey post test was adopted for multiple comparisons, when a normal distribution was not identified, the Kruskall-Wallis test and Dunn's or Tukey post-test were used, similarly the specific analysis of the pillar variables (UCLA and Universal Pillar) and systems retainer (Screwed and Cemented). For all tests, a significance level of 5% (α=0.05) was applied. The graphical analysis was considered through a bar graph for the data that presented normality with mean and standard deviation values, and the other analyzes that did not present normality was considered the creation of a boxplot for each comparative group. Implant prostheses using zirconia abutments have gained more and more space, in addition to the in vitro study, a systematic review was performed to compare marginal bone loss and prosthetic complications of rehabilitations using cemented and screwed zirconia abutments. Regarding cemented and screw-retained prostheses, due to conflicting evidence and the presence of many systematic reviews on the subject, an overview of systematic reviews was performed, with the objective of compiling the available information and evaluating the methodological quality of these studies regarding complications present in cemented or screw-retained implant prostheses(AU)