Effect of Inter-Implant Distance on Fracture Resistance of Implant-Supported Provisional Fixed Dental Prosthesis.

This study aimed to identify the ideal interimplant distance for optimum outcome on immediately loaded implant supported prosthesis. Hence this study was taken up to analyze the effect of varying interimplant distance on fracture resistance of implant supported provisional fixed dental prosthesis (FDP). A total of 24 bis-acrylate composite resin samples were prepared. Interimplant distance was present in the metal die for placement of dummy implants at distances of 14 mm, 21 mm, and 30 mm respectively. Wax-up for 3-unit, 4-unit, and 5-unit implant-supported provisional restoration was made. Silicone molds were used for making multiple interim prostheses using bis-acrylate composite material. All samples were subjected to fracture test in the universal testing machine with a crosshead speed of 1 mm/min. All samples were loaded with gradual force starting from 100 N until it fractured. The load was applied at the center of prosthesis. Data was analyzed by one-way analysis of variance and Bonferroni post hoc test. Mean fracture resistance of 3-unit provisional FDP at 14 mm of interimplant distance showed 1342.61 ± 179.15 N. Mean fracture resistance of 4-unit provisional FDP at 21 mm of interimplant distance showed 1420.44 ± 170.37 N. Mean fracture resistance of 5-unit provisional FDP at 30 mm of interimplant distance showed 791.61 ± 203.59 N. Both 14 mm and 21 mm of interimplant distance are suitable span lengths to be considered for the optimum outcome during immediately loading with implant-supported provisional restorations. Limitations of the study were that force application was static in nature and not dynamic and the arch form was not "U" shaped but longitudinal using Bis-Acryl material only with no cantilever. Future studies can be done to evaluate the fracture resistance of bis-acrylate material considering biomechanics and arch form of natural dentition. Distal cantilever should be considered along with different material for fabricating provisional restoration.

A comparative evaluation of the effect of eugenol exposure time on the bond strength of an etch-and-rinse and a self-etch adhesive to dentin: An in vitro study.

Aim: The study aimed to comparatively evaluate the effect of eugenol exposure time on the micro-shear bond strength (µ-SBS) of etch-and-rinse and a self-etch adhesive to dentin. Materials and Methods: One hundred and twelve teeth samples were prepared from bisectioning 56 freshly extracted human mandibular molars and were randomly divided into 14 subgroups of 8 samples each (n = 8). Three subgroups containing eugenol and a noneugenol-based restorative material were placed on the dentin surface and left for 24 h, 7 days, and 14 days, respectively, and were compared to a control. Two bonding systems were evaluated: one being etch-and-rinse and the other self-etch adhesive. The µ-SBS were calculated and expressed in MPa. Statistical Analysis: The data were analyzed using mixed model analysis of variance. The level of statistical significance was set at 5%. Results: There was a statistically significant reduction in the µ-SBS values when the self-etch adhesive was used, after the removal of eugenol-containing cement placed for 24 h. However, the reduction in the µ-SBS values after 7 days or 14 days was not significant. Conclusion: Exposure to eugenol containing temporary cement for 24 h significantly reduces the µ-SBS of self-etching adhesives to dentin. However, exposure for 1 week or more has minimal effects.

Fracture resistance of CAD/CAM milled versus direct hand-made interim laminate veneers.

Background: Comparative studies of interim veneer restorations crafted using subtractive computer-aided manufacturing (s-CAM) milling technology and traditional direct hand-made approaches are needed. Purpose: This comparative in vitro study evaluated the fracture resistance of two types of provisional veneer restorations for maxillary central incisors: milled (s-CAM) and traditional direct hand-made bis-acryl veneers. Materials and methods: Fifty maxillary right central incisor veneers (25 specimens per group) were fabricated and divided according to the fabrication method: (1) s-CAM milled (Structure CAD, VOCO Dental); and (2) hand-made (Protemp Plus, 3M). The restorations were cemented onto 3D-printed resin dies using temporary cement and subjected to 1000 cycles of thermal cycling between 5° and 55 °C. These restorations subsequently were subjected to compressive loading until fracture occurred. Images of the fractured samples were captured using a scanning electron microscope (SEM). Statistical analysis was performed using the one-way ANOVA test and the Mann-Whitney U test. Results: Significant differences (p < 0.001) in the fracture resistance were observed between the two groups. s-CAM milled interim veneers displayed higher fracture resistance values (439.60 ± 26 N) compared to the traditional method (149.15 ± 10 N). Conclusion: The manufacturing method significantly influences the fracture resistance of interim veneer restorations. s-CAM interim laminate veneer restorations for maxillary central incisors exhibit a fracture resistance superior to that of the traditional method using bis-acryl.Clinical relevanceClinicians should consider CAD/CAM milled veneers for scenarios demanding long-term interim restoration and the withstanding of high occlusal forces.

Physical and structural characterization of bis-acryl composite resin.

During the preparation of fixed prosthesis (including individual bridges and crowns) it is important to select the materials that have the best features and properties to predict a successful clinical treatment. The objective of this study was to determine if the chemical and structural characteristics could cause to increase the fracture resistance, we used four bis-acryl resins Luxatemp, Protemp, Structur and Telio. Three-points bending by Flexural test were performed in ten bars and they were carried out to compare with Anova test. In addition, the bis-acryl resins were analyzed by scanning electron microscopy, to analyze microstructure and morphology and the molecular structure were performed by Infrared Spectroscopy through Attenuated Total Reflectance. A higher flexural strength was found in Luxatemp and Structur with, no significant differences between this study groups. Regarding Protemp and Telio, these study groups showed a lower flexural strength when were compared with Luxatemp and Structur. These results corroborate SEM and ATR analysis because Luxatemp sample showed a regular size particle on the surface and chemically presents a long cross-linkage polymer chain. The presence of CO3, SiO2 and N-H groups as a fillers particle interacting with OH groups cause a higher flexural strength compared with another groups.

Timing implant provisionalization: Decision-making and systematic workflow.

OBJECTIVE: Provisionalization is an important step to achieve esthetic results in implant cases, and many different techniques for provisional restoration fabrication have been described. However, depending on the clinical scenario, the provisionalization strategy will require different approaches and timing. The clinician should modify the provisional restorations efficiently to reduce the number of disconnections from the implant, as repeated disconnections may have biological consequences. This article aims to schematize different scenarios requiring implant provisionalization and propose strategies to help the clinician condition the peri-implant tissues, respecting perio-prosthodontic fundamentals for soft tissue, biological, and esthetic stability. CLINICAL CONSIDERATIONS: The clinical outcomes of modern implant therapy aim to achieve results that emulate natural dentition. Different scenarios may require adjunct therapy, including hard- and soft-tissue grafting, which complicates treatment. The provisionalization strategy will vary depending on the initial condition of the tissues, the need for reconstructive procedures, and the timing of implant placement. Selecting the right strategy based on the case type is necessary to reduce treatment time and complications associated with inadequate prosthetic handling of the soft tissues. CLINICAL SIGNIFICANCE: Proper emergence profile conditioning through provisional restorations will allow for biologically sound and esthetically pleasing outcomes in implant restorations.

The Antibacterial and Antifungal Activity of Chlorhexidine Diacetate Incorporated into Acrylic Resins Used in Provisional Restorations.

Objective: The surface of provisional restorations applied before conventional or implant- supported fixed restorations may cause bacterial or fungal biofilm formation. The aim of this study was to evaluate the antimicrobial activity of acrylic resins used in provisional restorations modified with chlorhexidine diacetate. Methods: 120 cylindrical, auto-polymerized resin samples modified with chlorhexidine diacetate were prepared at concentrations of 0 (control), 1, 3, 5 wt %. The antimicrobial activity was examined against Streptococcus mutans, Enterococcus faecalis, and Candida albicans using Crystal Violet quantification, MTT assay, and Scanning Electron Microscopy. Data were analyzed by ANOVA and paired sample t-tests (α=0.05). Results: The addition of chlorhexidine diacetate influenced the growth rate and metabolic activity of microorganisms. The antimicrobial effect against C. albicans and S. mutans statistically increased with the percentage of chlorhexidine diacetate. E. faecalis bacteria were less affected by chlorhexidine diacetate compared to other pathogens. Conclusion: It has been shown that the effectiveness of CHDA in inhibiting the proliferation of microorganisms correlated positively with increasing concentration levels. More research is needed to confirm the impact of different chlorhexidine concentrations on the mechanical properties, clinical efficacy, and antimicrobial properties of CDHA.

Influence of Popular Beverages on the Fracture Resistance of Implant-Supported Bis-Acrylic Resin Provisional Crowns: An In Vitro Study.

Implant-supported provisional restorations are critical for improving the esthetics and shaping of the peri-implant tissue. The mechanical properties of these provisional materials can be influenced by saliva, food, beverages, and interactions between these materials in the oral environment. Therefore, the integrity of provisional restorations should be preserved throughout the treatment period. This study aimed to evaluate the fracture strength of implant-supported polymethyl methacrylate (PMMA) provisional restorations made of computer-aided design and computer-aided manufacturing when immersed in different solutions at a controlled temperature of 37 °C for 7 days. Each analog-pillar-crown set was submerged in different liquids: 10 pieces were placed in distilled water then in tea, coffee, red wine, and Coca Cola® for 1 week at a controlled oral temperature of 37 °C. The samples were then subjected to fracture forces. The moment of fracture of the crown was recorded and compared with those of the other samples. Specimens immersed in distilled water (control group) had the highest fracture resistance (mean [M] = 1331.00 ± 296.74 N), while those immersed in tea had the lowest mean resistance to fracture (mean [M] = 967.00 ± 281.86 N). Nutritional deficiency and inappropriate eating habits influence the fracture strength of temporary crowns, thereby rendering them more elastic or less resistant to fractures.

The Influence of Saliva pH on the Fracture Resistance of Two Types of Implant-Supported Bis-Acrylic Resin Provisional Crowns-An In Vitro Study.

Temporary restorations play a fundamental role in oral rehabilitation. A properly adapted implant-supported provisional restoration implies better esthetics, contouring and architectural modeling of the upper peri-implant tissue. This study aimed to evaluate the influence of oral pH on the fracture resistance of implant-supported provisional restorations made with two brands of bis-acrylic resin (LuxaCrown® and Protemp™ 4) and to compare the fracture resistance of these two materials. Twenty crowns (ten manufactured using each brand) served as a control, and another forty crowns (twenty of each brand) were aged using artificial saliva with pHs of 4 or 7, for 7 days at 37 °C, in an attempt to simulate the behavior of these materials inside the oral cavity. Subsequently, all crowns were subjected to the application of a force at a constant speed, in a universal testing machine, until fracture was achieved. The LuxaCrown® brand showed greater resistance to fracture than the Protemp™ 4 brand. Salivary pH did not influence the fracture resistance of provisional LuxaCrown® crowns but did influence the fracture resistance of provisional Protemp™ 4 crowns.

Factors affecting flexural strength of 3D-printed resins: A systematic review.

PURPOSE: The strength of 3D-printed resins is affected by different factors, but review articles clarifying these factors are limited. This review lists the factors affecting the strength of 3D-printed resins and the possible correlations between them to answer the study question: What are the factors affecting the flexural strength of 3D-printed resins? METHODS: A database search (PubMed, Google Scholar, and Scopus) was performed, limited to English-language publications between 2010 and February 1, 2022. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used for study selection. The modified Consolidated Standards of Reporting Trials (CONSORT) checklist was used to determine the risk of bias of the included studies in this review. The data analysis was descriptive due to the presence of many variables in the included studies. RESULTS: Out of 123 studies, 26 were reviewed for full-text analysis, and 19 met the inclusion criteria and were thus included in this systematic review. The included studies were divided according to the investigated resin: 5 studies tested provisional restorations, seven tested denture base resins, 2 tested occlusal devices, 3 tested orthodontic appliances, 1 tested denture teeth, and 1 tested surgical guide resins. These studies investigated the flexural strength of 3D-printed resins, with different factors, such as reinforcement with fillers or nanofillers; printing orientation, angulation, and directions; post-polymerization time and temperature; third-party printing (switching between printers and materials); printing layer thickness; and post-printing rinsing time. Most factors significantly affected the flexural strength of 3D-printed resin. CONCLUSIONS: The strength of 3D-printed resins could be improved with one or more of the following factors: filler or nanofiller addition; printing orientation, angulation, or directions; printing layer thickness; and post-polymerization time and temperature. However, further studies combining these factors are recommended.

Effects of nanohybrid flowable resin-based composites on fibroblast viability using different light-curing units.

PURPOSE: To investigate the in vitro cytotoxic effects of Bis-GMA-containing and Bis-GMA-free flowable resin-based composites (RBCs) on primary human gingival fibroblast cells (hGFc) using direct and indirect curing methods and three different light-curing units (LCUs). MATERIALS AND METHODS: Cells were isolated and cultured in vitro in 24-well plates. The plates were divided into treatment (cells with RBC), control (cells only), and blank (media only) groups. In the treatment groups, two types of nanohybrid flowable RBCs were used: Bis-GMA-free and Bis-GMA groups. Each treatment group was subdivided according to the curing method, i.e., direct curing (RBC was injected into the wells and cured directly on the attached cells) and indirect curing (the samples were pre-cured outside of the well plate and then added to the well plate with cells). To vary the LCU, the subgroups were further divided into three groups: multiple-emission peak light-emitting diode, single-emission peak light-emitting diode, and quartz-tungsten-halogen units. Curing was conducted for 20 seconds. The hGFc cytotoxicity was evaluated via 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay after 24, 48, and 72 hours of culturing. RESULTS: The MTT assay results showed that both RBCs were significantly cytotoxic toward hGFc compared to the control group (p < 0.0001). The Bis-GMA group was significantly more cytotoxic to the cells compared to the Bis-GMA-free group. In addition, the curing method and time interval affected cell viability regardless of the LCU used. CONCLUSION: The Bis-GMA flowable RBC and direct curing method had the highest cytotoxic effects on hGFc regardless of the LCU used. Careful selection of flowable RBCs and proper curing techniques are required to decrease the cytotoxic effects on hGFc and improve the clinical handling of oral tissues.

Surface roughness and marginal adaptation of stereolithography versus digital light processing three-dimensional printed resins: An in-vitro study.

Aim: The aim of this study was to assess surface roughness and marginal adaptation of Stereolithographic versus Digital Light Processed three-dimensional (3D) printed provisional resins. Materials and Methods: A 3-unit fixed partial denture (FPD) preparation was done on ideal model irrespective to 44-46. The Model was scanned and a 3-unit FPD was designed using 3-shape software. The STL file was transferred to two different 3D printers - Sprintray digital light processing (DLP) and Formlabs stereolithography (SLA). Eight samples were printed per group (total of 16 samples) using C and B temporary tooth-colored resin and cured according to the manufacturer's instructions. Marginal adaptation was checked for six surfaces per tooth for all the samples using a stereomicroscope. Surface roughness was also calculated for four samples from each group before and after polishing (pumice slurry + rouge and cotton buff) using a contact profilometer. Results: The mean maximum marginal gap overall, was seen for the DLP group on the mesiobuccal surface of the first premolar, i.e., 178.8 ± 8.35 µm, while the minimal marginal gap was seen for the SLA group on the mesiolingual surface of first molar - 32.5 ± 7.07 µm. Furthermore, all the DLP samples showed a statistically significant higher mean marginal gap as compared to SLA samples (P < 0.005). All the samples showed surface roughness within the acceptable range. There was a statistically significant difference noted in Rz (roughness depth) before and after polishing (P < 0.05). Conclusion: 3D printed temporary resin FPD via SLA showed a much better marginal adaptation (49.6 µm mean marginal gap for 46 and 106.8 µm for 44) as compared to those printed via DLP (101.8 µm mean marginal gap for 46 and 157.5 µm for 44). All the samples showed an acceptable surface roughness. Clinical Relevance: 3D printed temporaries have shown good marginal fit and adaptation and are a viable choice in patients where temporaries has to be given for long term before a final prosthesis can be fabricated (especially for full mouth rehabilitations).

Evaluation of biofilm formation on acrylic resins used to fabricate dental temporary restorations with the use of 3D printing technology.

BACKGROUND: Temporary implant-retained restorations are required to support function and esthetics of the masticatory system until the final restoration is completed and delivered. Acrylic resins are commonly used in prosthetic dentistry and lately they have been used in three-dimensional (3D) printing technology. Since this technology it is fairly new, the number of studies on their susceptibility to microbial adhesion is low. Restorations placed even for a short period of time may become the reservoir for microorganisms that may affect the peri-implant tissues and trigger inflammation endangering further procedures. The aim of the study was to test the biofilm formation on acrylamide resins used to fabricate temporary restorations in 3D printing technology and to assess if the post-processing impacts microbial adhesion. METHODS: Disk-shaped samples were manufactured using the 3D printing technique from three commercially available UV-curable resins consisting of acrylate and methacrylate oligomers with various time and inhibitors of polymerization (NextDent MFH bleach, NextDent 3D Plus, MazicD Temp). The tested samples were raw, polished and glazed. The ability to create biofilm by oral streptococci (S. mutans, S. sanguinis, S. oralis, S. mitis) was tested, as well as species with higher pathogenic potential: Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans. The roughness of the materials was measured by an atomic force microscope. Biofilm formation was assessed after 72 h of incubation by crystal violet staining with absorbance measurement, quantification of viable microorganisms, and imaging with a scanning electron microscope (SEM). RESULTS: Each tested species formed the biofilm on the samples of all three resins. Post-production processing resulted in reduced roughness parameters and biofilm abundance. Polishing and glazing reduced roughness parameters significantly in the NextDent resin group, while glazing alone caused significant surface smoothing in Mazic Temp. A thin layer of microbial biofilm covered glazed resin surfaces with a small number of microorganisms for all tested strains except S. oralis and S. epidermidis, while raw and polished surfaces were covered with a dense biofilm, rich in microorganisms. CONCLUSIONS: UV-curing acrylic resins used for fabricating temporary restorations in the 3D technology are the interim solution, but are susceptible to adhesion and biofilm formation by oral streptococci, staphylococci and Candida. Post-processing and particularly glazing process significantly reduce bacterial biofilm formation and the risk of failure of final restoration.

Accuracy of Additively Manufactured and Milled Interim 3-Unit Fixed Dental Prostheses.

PURPOSE: To investigate the accuracy of additive manufacturing (AM) by means of internal fit of fixed dental prostheses (FDPs) fabricated with two AM technologies using different resins and printing modes (validated vs nonvalidated) compared to milling and direct manual methods. MATERIAL AND METHODS: Sixty 3-unit interim FDPs replacing the first mandibular molar were divided into 6 groups (n = 10): manual (Protemp 4), milled (Telio-CAD), and AM groups were subdivided based on AM technology (direct light processing (Rapidshape P30 [RS]) and stereolithography (FormLabs 2 [FL])) and the polymer type (P-Pro-C&B [St] and SHERAprint-cb [Sh]) (RS-St, RS-Sh, FL-St, FL-Sh). Validated (RS-Sh and RS-St) or nonvalidated (FL-St and FL-Sh) modes were adopted for AM. The specimens were scanned to 3D align (GOM inspect) according to the triple scan method. The internal space between the FDPs and preparation surfaces in four sites (marginal, axial, occlusal, and total) was measured using equidistant surface points (GOM Inspect). Statistical analysis was done using Kruskal Wallis and Dunn post-hoc tests. (α = 0.05). RESULTS: One AM group (FL-Sh) and milling exhibited better adaptation compared to manual and RS-St at molar site (p < 0.05). FDPs with St resin (FL-St and RS-St) displayed bigger marginal space than milled, FL-Sh, and RS-Sh. The nonvalidated printing mode showed better mean space results (p < 0.05) with higher predictability and repeatability (p < 0.001). CONCLUSIONS: The AM interim FDPs tested provided valid alternatives to the milled ones in regard to their accuracy results. The printing mode, resin, and the AM technology used significantly influenced the manufacturing accuracy of interim FDPs, particularly at the marginal area. The nonvalidated printing mode with lower-cost 3D printers is a promising solution for clinical applications.

Interleukin-1ß activity in gingival crevicular fluid of abutment teeth with temporary fixed restorations versus final fixed restorations: Prospective observational study.

OBJECTIVE: To compare the effect of temporary fixed restorations to final fixed restorations on gingival health of abutment tooth by evaluating the level of IL-1ß in gingival crevicular fluid (GCF) as an inflammatory biomarker. SUBJECTS AND METHODS: It was a nonrandomized prospective observational study. Samples of GCF were collected from 24 participants with provisional and permanent definitive full-coverage restorations with subgingival margin placements at three intervals for each participant: Interval 1, after preparation and immediately before cementation of temporary fixed restoration. Interval 2, after two weeks of temporization and before receiving the final fixed restoration. Interval 3, after two weeks of final fixed restorations. GCF were collected from gingival crevice of the abutment tooth by pre-prepared filter paper with dimensions of 2mmx13mm. They were prepared for IL-1ß concentration assay by enzyme-linked immuno sorbent assay - analysis (ELIZA). RESULTS: Were analyzed by SAS® software, Descriptive means and medians were used and the repeated ANVOA test was applied (1st interval) showed the highest level of IL-ß (13.587 ± 5.735). In 2nd interval the level of IL-ß was significantly reduced (9.602 ± 3.279). While, in 3rd interval the level of IL-ß was the lowest (6.293 ± 3.279). CONCLUSION: The material and technique of fabrication of both temporary and final fixed restorations are critical for gingival health. PMMA CAD-CAM based temporary restorations showed to be compatible to gingival health by decreasing the level of IL-ß level, but the zirconia as a final fixed restoration showed to have optimum compatible effect on gingival health.

Development of 3D printed resin reinforced with modified ZrO2 nanoparticles for long-term provisional dental restorations.

OBJECTIVE: To characterize and investigate efficacy of loading functionalized ZrO2 nanoparticles in 3-dimensional (3D) printed acrylate ester-based resin subjected to accelerated aging in artificial saliva. As well as to evaluate the effect of ZrO2 nanoparticle volume fraction addition on mechanical and physical properties of printed composite. METHODS: Functionalized ZrO2 nanoparticles were characterized using TEM and Raman spectroscopy. 3D printed dental resin was reinforced, with ZrO2 nanoparticles, in the concentration range (0-5wt.%). The resulted nanocomposites, in term of structure and physical/mechanical properties were evaluated using different mechanical testing, microscopic and spectroscopic techniques. RESULTS: ZrO2 based nanocomposite was successful and formed composites were more ductile. Degree of conversion was significant at the highest level with blank resin and 1wt.%. Sorption revealed reduction associated with volume fraction significant to neat resin, however solubility indicated neat and 4wt.% had the lowest significant dissolution. Vickers represented critical positive correlation with filler content, while nanohardness and elasticity behaved symmetrically and had the maximum strength at 3wt.% addition. In addition, 3wt.% showed the highest fracture toughness and modulus. Improvement of flexural strength was significantly linked to filler concentration. Overall properties dramatically were enhanced after 3 months aging in artificial saliva, especially degree of conversion, microhardness, nanoindentation/elasticity, and flexural modulus. However, significant reduction was observed with flexural modulus and fracture toughness. SIGNIFICANCE: The outcomes suggest that the newly developed 3D printed nanocomposites modified with ZrO2 nanoparticle have the superior potential and efficacy as long-term provisional dental restoration materials.

Comparison of fracture strength after thermo-mechanical aging between provisional crowns made with CAD/CAM and conventional method.

PURPOSE: The objectives of this study were to evaluate the fracture strength and fracture patterns of provisional crowns fabricated from different materials and techniques after receiving stress from a simulated oral condition. MATERIALS AND METHODS: A monomethacrylate-based resin (Unifast Trad) and a bis-acryl-based (Protemp 4) resin were used to fabricate provisional crowns using conventional direct technique. A milled monomethacrylate resin (Brylic Solid) and a 3D-printed bis-acrylate resin (Freeprint Temp) were chosen to fabricate provisional crowns using the CAD/CAM process. All cemented provisional crowns (n=10/group) were subjected to thermal cycling (5,000 cycles at 5°-55℃) and cyclic occlusal load (100 N at 4 Hz for 100,000 cycles). Maximum force at fracture was tested using a universal testing machine. RESULTS: Maximum force at fracture (mean ± SD, N) of each group was 657.87 ± 82.84 for Unifast Trad, 1125.94 ± 168.07 for Protemp4, 953.60 ± 58.88 for Brylic Solid, and 1004.19 ± 122.18 for Freeprint Temp. One-way ANOVA with Tamhane post hoc test showed that the fracture strength of Unifast Trad was statistically significantly lower than others (P<.01). No statistically significant difference was noted among other groups. For failure pattern analysis, Unifast Trad and Brylic Solid showed less damage than Protemp 4 and Freeprint Temp groups. CONCLUSION: Provisional crowns fabricated using the CAD/CAM process and the conventionally fabricated bis-acryl resins exhibited significant higher fracture strength compared to conventionally fabricated monomethacrylate resins after the aging regimen. Therefore, CAD/CAM milling and 3D printing of provisional restorations may be good alternatives for long term provisionalization.

Effect of fiber-reinforcement on the strength of polymer materials for provisional restorations: An in vitro study.

OBJECTIVE: The purpose of this study was to evaluate the effect of three different methods of fiber reinforcement (glass fibers preimpregnated, glass fibers nonpreimpregnated, and polyethylene fibers) on the flexural strength and modulus of elasticity of poly-methyl-methacrylate resin (PMMA) and Bis-Gma materials. MATERIALS AND METHODS: A total of 60 specimens of autopolymerizing PMMA resin specimens were fabricated using a stainless steel matrix with dimensions of (37.5± 2) × (3 ± 0.1) × (3 ± 0.1) mm according to the standards of ISO 10477. The autopolymerizing resins used in this study were: (a) JET, (b) TRIM, (c) PROTEMP. The fibers used in this study were STICK (Glass fiber preimpregnated), POLYDENTIA (Glass fiber nonpreimpregnated), RIBBOND (Polyethylene fiber). The specimens were tested by three-point bending test and the flexural strength and modulus of elasticity were recorded. The data of each resin type were analyzed by analysis of variance using a significance level of 0.05 to determine the mean differences. RESULTS: The integration of reinforcing fibers in the mass of resins for provisional restorations increased both the flexural strength and the modulus of elasticity in all tested combinations compared to control groups. After the three-point bending test, the specimens were not completely fractured and the parts remained together due to the fibers. CONCLUSIONS: Fiber reinforcement is an effective method to increase mechanical properties of provisional restorative resins. Reinforcement with fibers enhances the flexural strength and the modulus of elasticity of the specimens compared to unreinforced (control) group. CLINICAL SIGNIFICANCE: The reinforcement of resin materials used for provisional restorations with fibers can increase mechanical strength and may improve the clinical performance and the longevity of provisional restorations during their clinical function.

"Comparative Evaluation of the Effect of Three Polishing Agents on Staining Characteristics of Provisional Restorative Material:" An in vitro Study.

AIM: The present study aimed to evaluate the effect of three various polishing agents on provisional restorative material on immersion in a staining solutions. OBJECTIVES: The objective of the study is (1) To evaluate the effect of pumice on staining characteristics of provisional restorative material before and after immersion in chlorhexidine. (2) To evaluate the effect of aluminum oxide paste on staining characteristics of provisional restorative material before and after immersion in chlorhexidine. (3) To evaluate the effect of diamond paste on staining characteristics of provisional restorative material before and after immersion in chlorhexidine. (4) To compare and assess the outcome of three polishing agents on staining characteristics of provisional restorative material. MATERIALS AND METHODS: Sixty samples (10 mm × 2 mm) were fabricated of bis-acryl composites (Protemp™ 4) by utilizing a metal mold. The samples were grouped into three groups (n = 20), and various polishing agents were used, including pumice, aluminum oxide paste, and diamond polishing paste. The samples that were not exposed to any polishing agent served as the control group. The samples were kept in a water bath for a day at 37°C and were stained with chlorhexidine mouthwash. The color of all specimens was measured with a spectrophotometer before and after polishing, and color changes (ΔE) were calculated. RESULTS: By using one-way ANOVA, significant difference was found in mean color change in three polishing materials (F = 4.44, P = 0.016). By using Tukey test, statistically significant difference was found among pumice and aluminum oxide paste (P = 0.027), among pumice and diamond paste (P = 0.041) and no significant difference was found among aluminum oxide paste and diamond paste (P = 0.985). CONCLUSION: Pumice exhibited less staining which was statistically significant when compared with aluminum oxide paste and diamond paste. Hence, it can be considered the most efficient polishing agent.

Consideraciones para el incremento de dimensión vertical de oclusión. Reporte de un caso / Considerations for the increase of occlusal vertical dimension. Report of a case

RESUMEN La dimensión vertical de oclusión (DVO) está representada por la distancia entre dos puntos, que no se pierde; sin embargo, puede verse aumentada o disminuida. Depende en buena medida de la dentición presente. Entidades patológicas como la atrición severa pueden influir su condición. La ruta clínica para llegar a la determinación de realizar un incremento de DVO es un proceso meticuloso, parte de un diagnóstico certero, cuantificación de la misma, así como la vía para realizar el procedimiento. Existen múltiples métodos para la terapéutica del incremento de DVO: dispositivos removibles o fijos. La elección del plan de tratamiento será con base en las particularidades de cada paciente. No existe tratamiento universal sino uno ideal para cada situación específica. Este caso describe las consideraciones previas al aumento de DVO en un paciente masculino de 68 años con atrición generalizada. Se evaluó la magnitud de la reducción de DVO, perfil facial y estética mediante análisis fotográfico y video; el esquema oclusal y la estructura dental presente. La literatura propone calcular con diferentes métodos el restablecimiento de la DVO; antes de elegir alguno se requiere definir y especular qué tanto se encuentra disminuida, para ello no basta un análisis estático o de simple apreciación, debe considerarse el aspecto facial, así como la dinámica mandibular. El incremento de la DVO en una sola intención, mediante restauraciones provisionales, mantenidas dentro de los parámetros de comodidad, es un excelente recurso para ejecutarla, el paciente experimenta una fase de adaptación favorable y sin complicaciones sintomáticas.

ABSTRACT Occlusal vertical dimension (OVD) is represented by the distance between two points, which is not lost, however, can be increased or decreased. Depends to a good extent on the present dentition. Pathological entities such as severe attrition can influence their condition. Clinical route to arrive at the determination to perform an increase of OVD is a meticulous process, part of a correct diagnosis, quantifi cation of the same, as well as the way to perform the procedure. There are multiple methods for this treatment: removable or fi xed devices. Choice of treatment will be based on the particularities of each patient. There is no universal treatment but an ideal for each specific situation. This case describes the considerations prior to the increase of OVD in a 68-year-old male patient with generalized attrition. Magnitude of OVD reduction, facial and aesthetic profi le was evaluated by means of photographic and video analysis; the occlusal scheme and the dental structure present. Literature consulted proposes to calculate with different methods the reestablishment of OVD, before choosing one it is necessary to defi ne and to speculate how much it is diminished, for it is not enough a static analysis or of simple appreciation must consider the facial aspect, as well as the mandibular dynamics. Increasing OVD in a single intention, through provisional restorations, maintained within the parameters of comfort, is an excellent resource to execute it, the patient undergoes a phase of favorable adaptation and without symptomatic complications.

Customized Implant Full-Mouth Rehabilitation: A Biomechanical Depiction.

The rationale for implant full-mouth rehabilitation is believed to present the better quality of life to the older population. This type of modalities preserves the soft and hard tissue of oral cavity. It is also helpful to check the temporomandibular joint disease. Literature exposes that implant full-mouth fixed rehabilitation is one of the taxing procedures in the field of prosthodontics. The current clinical report discusses a customized biomechanical approach for the fabrication of implant complete-mouth rehabilitation. A systematic approach in managing this patient can lead to a predictable and favorable prognosis. This article also presents the stages of prosthodontic rehabilitation from diagnosis to final treatment planning as a customized radiographical Gutta Percha template, precise implant surgery of 12 implants (ADIN, Dental Implant System, Israel) over the both the arches and provisional restorations with group function occlusion. Lastly, full-mouth restorations were fabricated as cement-retained (open hole) metal-ceramic restoration. Advocated patient is absolutely happy with customized implant full-mouth rehabilitation.