Provisional Restoration Research Articles

Fracture Resistance Comparative Analysis of Milled-Derived vs. 3D-Printed CAD/CAM Materials for Single-Unit Restorations.

The aim of this study was to evaluate and compare the fracture resistance of a single-unit fixed prosthesis, using a CAD/CAM PMMA material and two printed materials (3DPPa and 3DPPb). A typodont with a specific preparation for a full crown was used; a digital impression was made with a state-of-the-art scanner (PrimeScanTM, Dentsply-SironaTM, New York, NY, USA), and a full coverage restoration was designed using a biogeneric design proposal by means of specific software (InLAB 22.1, Dentsply-Sirona, NY, USA). Sixty crowns were prepared, divided into three groups according to the material: 3DPPa (n = 20), 3DPPb (n = 20), both 3D-printed from the .STL file with a resolution of 50 μm, and PMMA (n = 20) milled-derived, which were subjected to a thermocycling process. A universal testing machine (Universal/Tensile Testing Machine, Autograph AGS-X Series) with integrated software (TRAPEZIUM LITE X) equipped with a 20 kN load cell was used to determine the fracture resistance. Significant differences were found by Kruskal-Wallis test and multiple comparisons (p < 0.05) in fracture resistance between materials. The fracture resistance for the PMMA material was higher, and the standard deviation was lower (x = 1427.9; sd = 36.9 N) compared to the 3DPPa (x = 1231; sd = 380.1 N) and 3DPPb (x = 1029.9; sd = 166.46 N) prints. The restorations from the milled-derived group showed higher average fracture resistance than the provisional restorations obtained from the printed groups. However, the results demonstrated that all three materials analyzed in single-unit restorations are capable of withstanding the average masticatory forces.

Mechanical properties of 3D-printed and milled composite resins for definitive restorations: An in vitro comparison of initial strength and fatigue behavior.

To evaluate the flexural strength and fatigue behavior of a novel 3D-printed composite resin for definitive restorations. Fifty disc-shaped specimens were manufactured from each of a nanohybrid composite resin (NHC), polymer-infiltrated ceramic network (PICN), and 3D-printed composite resin (3D) with CAD-CAM technology. Biaxial flexural strength (σin ) (n = 30 per group) and biaxial flexural fatigue strength (σff ) (n = 20 per group) were measured using piston-on-three-balls method, employing a staircase approach of 105 cycles. Weibull statistics, relative-strength degradation calculations, and fractography were performed. The results were analyzed with 1-way ANOVA and Games-Howell post hoc test (α = 0.05). Significant differences in σin and σff among the groups (p < 0.001) were detected. The NHC group provided the highest mean ± standard deviation σin and σff (237.3 ± 31.6 MPa and 141.3 ± 3.8 MPa), followed by the PICN (140.3 ± 12.9 MPa and 73.5 ± 9.9 MPa) and the 3D (83.6 ± 18.5 MPa and 37.4 ± 23.8 MPa) groups. The 3D group exhibited significantly lower Weibull modulus (m = 4.7) and up to 15% higher relative strength degradation with areas of nonhomogeneous microstructure as possible fracture origins. The 3D-printed composite resin exhibited the lowest mechanical properties, where areas of nonhomogeneous microstructure developed during the mixing procedure served as potential fracture origins. The clinical indications of the investigated novel 3D-printed composite resin should be limited to long-term provisional restorations. A cautious procedure for mixing the components is crucial before the 3D-printing process, since nonhomogeneous areas developed during the mixing could act as fracture origins.

Effects of postpolymerization time and temperature on the flexural properties and hardness profile of three-dimensional printed provisional resin

Background/purposeThree-dimensional (3D) printing technique was widely used for provisional restorations in clinical use. However, the effects of post-polymerization temperature and time on the flexural properties and hardness profile were not fully elucidated yet. The purpose of this study is to investigate the effects of post-polymerization temperature and time on the flexural properties and hardness profile of the provisional restoration. Materials and methods3D-printing provisional resin was printed and post-polymerized at various temperatures (room temperature, 40 °C, 60 °C and 80 °C) and periods (0, 15, 30, 60, 90 and 120 min of photopolymerization). Afterwards, the flexural strength, flexural modulus, surface hardness, and internal hardness at different depth were evaluated. ResultsThe group post-polymerized without concurrent heating had significantly shallow depth of cure comparing to the heating counterparts. The surface hardness of the groups post-polymerized at different temperatures did not show any difference. All groups with post-polymerization temperature at 40 °C, 60 °C and 80 °C and post-polymerization time ranged between 15 and 90 min, had curing depth between 3 and 4 mm. Group post-polymerized without concurrent heating has significantly shallow depth of cure comparing to the heating counterparts. ConclusionPost-polymerization at an elevated temperature, preferably 60 °C, is suggested. The wall thickness of the 3D-printing provisional prosthesis thinner than 3–4 mm is recommended.

Critical review on bone grafting during immediate implant placement.

In the last 20 years, immediate implant placement has been proposed as a predictable protocol to replace failing teeth. The research conducted in preclinical and clinical studies have focused on soft and hard tissue changes following tooth extraction and immediate implant placement. Different approaches for hard and soft tissue grafting together with provisional restorations have been proposed to compensate tissue alterations. This review analyzed some relevant clinical and preclinical literature focusing on the impact of bone grafting procedures on immediate implant placement in terms of hard and soft tissue changes, aesthetic results, and patient-related outcomes.

Immediate Implant Placement in the Esthetic Zone Using a Novel Tapered Implant Design and a Digital Integrated Workflow: A Case Series.

The purpose of this case series was to assess the application of a novel self-cutting, tapered implant (Straumann® BLX, Institut Straumann AG, Basel, Switzerland) in combination with a digital integrated prosthetic workflow for the immediate placement and restoration. Fourteen consecutive patients, requiring replacement of a single hopeless maxillary or mandibular tooth, meeting the clinical and radiographic indication criteria for immediate implant placement, were treated. All cases followed the same digitally-guided procedure of extraction and immediate implant placement. Immediate temporization with full contoured screw-retained provisionals was performed using an integrated digital workflow. After implant placement and dual-zone bone and soft tissue augmentation, connecting geometries and emergence profiles were finalized. The average implant insertion torque was 53.2 ± 14.9 Ncm and ranged between 35 and 80 Ncm, allowing immediate provisional restoration in all cases. Final restorations were delivered three months after implant placement. An implant survival rate of 100% was observed at the 1-year recall after loading. The results of this case series suggest that immediate placement of novel tapered implants and immediate provisionalization using an integrated digital workflow can result in predictable functional and esthetic results for the immediate transition of failing single teeth in the esthetic area.

Modified Technique to Rehabilitate American Society of Anesthesiology-III Patient, Through Flapless Procedure With Computed Tomography-Guided Surgery.

The aim was to evaluate the safety and effectiveness of a computed tomography-guided surgery implant placement with a flapless technique and immediate functional loading in an American Society of Anesthesiology-III patient. This technical note involved a 64-year-old American Society of Anesthesiology-III patient. Her hopeless teeth were extracted and a restorative evaluation was provided as a prosthetic reference. The surgical procedure was based on the flapless technique that let us to use local anesthesia. The authors used an All-on-4 concept restoration for maxilla and conventional fixed prosthesis procedures for jaw rehabilitation. The authors placed 4 tilted implants in the upper maxilla and 6 right implants in the jaw. Implants were loaded with a provisional prosthesis on the same day of surgery. Five months later, provisional restoration was removed; the authors placed into the ceramic crowns 2 Procera Implant Bridge (Nobel Biocare) frameworks, developed through computer-aided design/computer-aided manufacturing technology. Computed tomography-guided surgery is a minimally invasive technique that allows, through a flapless approach, safer and more predictable procedures. In this technical note, the authors achieved accurate implant placement and precise fit of restoration with natural looking appearance; this patient-oriented-treatment led to a reduced healing time with better compliance.

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.

A novel technique for implant-supported fixed complete rehabilitation based on a dynamic virtual patient

BackgroundA digital workflow for implant-supported fixed complete prostheses (ISFCP) using photogrammetry (PG), virtual articulator (VA), and virtual facebow (VF) data remains a challenge. MethodsThe novel ISFCP technique included four steps: (1) formation of a dynamic virtual patient, (2) integration of PG data, (3) fabrication of a diagnostic ISFCP, and (4) fabrication of a definitive ISFCP and test of the deviation. ResultsDynamic virtual patients were formed by integrating PG, VA, and VF data. The cumulative root mean square deviation between the designed data and actual definitive prosthesis was 140.4 µm. ConclusionsThe novel technique for ISFCP fabrication described in this paper can help optimise the clinical efficiency and quality of ISFCP but requires an initial learning curve. Clinical SignificanceThis technique provides a direct workflow, using PG, VA, and VF data, to fabricate ISFCP based on the provisional restoration.

Influence of aging process and restoration thickness on the fracture resistance of provisional crowns: A comparative study

BackgroundThe advancement of digital dentistry enhanced the fabrication of indirect provisional restorations utilizing durable materials, yet the performance of provisional crowns fabricated with various techniques, and different thickness remains unknown. Thus, this in-vitro study aimed to evaluate the influence of restoration thickness and aging on the fracture behavior of provisional crowns fabricated using different techniques. MethodsA dentiform maxillary first molar was prepared using a highly filled epoxy resin material to construct identical die replicas. Four groups of provisional crowns were fabricated: Group 1 was milled at 1.5 mm occlusal thickness; Group 2 was milled at 0.9 mm thickness; Group 3 was 3D-printed at 1.5 mm occlusal thickness; and Group 4 was 3D-printed at 0.9 mm occlusal thickness. Eight crowns from each group were subjected to a thermocycling process for 5000 cycles between baths held at 5 °C and 55 °C with a dwell time of 30 s and transfer time of 5 s. All crowns (aged and non-aged (control)) were loaded for fracturing using a universal testing machine at a 0.5 mm/min crosshead speed. Data were analyzed using a two-way analysis of variance and multiple comparisons at (α = 0.05). ResultsThe maximum mean force load was found in the non-aged milled group (M1.5) at 1706.36 ± 124.07 N; the minimum mean force load was recorded for the aged 3D-printed group (3D0.9) at 552.49 ± 173.46 N. A significant difference was observed before and after thermocycling (p < 0.01). ConclusionComputer-aided design and manufacture of milled provisional crowns is superior to 3D-printed crowns for fracture resistance.

Provisional restorations (Part 2).

This chapter will emphasise the need to: 1) Provide a provisional restoration following tooth preparation to protect the pulp; secure positional stability, function and aesthetics; and maintain gingival health; 2) Consider using long-term provisional restorations to assess aesthetic, occlusal and periodontal changes before embarking on definitive restorations; 3) Distinguish between preparations for conventional and adhesive restorations when providing provisional restorations; 4) Determine in advance the type of provisional restorations and materials to be used, ideally, while treatment planning; 5) Be aware of materials for making provisional restorations and how to control potential hazards; and 6) Make provisional restorations to a high standard to ensure a predictable restorative outcome.

The natural CAD/CAM anterior implant single tooth restoration: A novel digital workflow.

To report a novel digital workflow to replace an anterior maxillary tooth lost due to trauma with an implant multilayer restoration by using the patient's extracted tooth as a final crown restoration using computer-aided design/computer-aided manufacturing (CAD/CAM) technology. Instead of using the patient's natural tooth as an immediate provisional restoration to achieve predictable results in terms of esthetics and soft tissue structure, a novel digital strategy was performed to obtain a natural final crown restoration by using the patient's tooth associated with a lithium disilicate customized implant abutment. The perspective of using this strategic approach for implant restorative dental treatments in patients with traumatic root fractures in the anterior region has great potential as it helps to maintain the emergence profile of the natural dentition and esthetics. Optimal esthetic outcomes are challenging in implant dentistry regarding soft tissue structure and morphology factors. Using natural teeth from surgery to deliver the final restoration might be beneficial when an anterior tooth is lost due to trauma.

Prosthetic rehabilitation with implant-supported fixed prosthesis in a completely edentulous patient: A clinical report

To present clinical strategies for prosthetic rehabilitation of completely edentulous patients using immediate-loading basal implants.A 58-year-old female patient was referred to the Department of Prosthodontics for restoration of her completely edentulous maxilla and mandible with a fixed full-arch implant-prosthetic rehabilitation. Since the patient lacks adequate bone in the posterior maxilla and is not willing to undergo a removable interim prosthesis, an immediate loading protocol along with 8 single-piece basal implants, including 2 pterygoid implants in the maxillary arch and 6 single-piece basal implants in the mandibular arch, was selected as the treatment option, followed by an acrylic provisional restoration. Four months later, a definitive fixed implant-supported prosthesis was delivered.This treatment strategy may be considered for rehabilitating patients with atrophic ridges demanding fixed provisional prostheses throughout the healing period and can be employed even in immediate implant placement after extraction.

Provisional restorations (Part 1).

This chapter will emphasise the need to: 1) Provide a provisional restoration following tooth preparation to protect the pulp; secure positional stability, function and aesthetics; and maintain gingival health; 2) Consider using long-term provisional restorations to assess aesthetic, occlusal and periodontal changes before embarking on definitive restorations; 3) Distinguish between preparations for conventional and adhesive restorations when providing provisional restorations; 4) Determine in advance the type of provisional restorations and materials to be used, ideally, while treatment planning; 5) Be aware of materials for making provisional restorations and how to control potential hazards; and 6) Make provisional restorations to a high standard to ensure a predictable restorative outcome.

The efficacy of reinforcement of glass fibers and ZrO2 nanoparticles on the mechanical properties of autopolymerizing provisional restorations (PMMA)

Objectiveto investigate and compare the reinforcing effects of glass fibers (GFs) and ZrO2 nanoparticles at different ratios on the Flexural Strength (FS), Microhardness (MH), and Surface Roughness (SR) of autopolymerizing provisional PMMA. MethodsA total of one hundred and twenty specimens of autopolymerizing PMMA were prepared for FS, MH, and SR tests and grouped as follows: no additives (control group), for the tested groups, different ratios of GFs and ZrO2 at 5% of autopolymerizing PMMA were incorporated. The ratios of GFs/ZrO2 nanoparticles were 0%-5%, 1%-4%, 2%-3%, 2.5%-2.5%, 3%-2%, 4%-1% and 5%-0% (n = 5). The FS was evaluated using the three-point bending test, MH was evaluated using the Vickers microhardness tester and SR was evaluated using a contact-type profilometer. Data were analyzed using ANOVA, Tukey’s test, and Person correlation at 0.05 level of significance. ResultsThe unreinforced group had the lowest FS, MH, and SR mean values followed by (0%GFs + 5% ZrO2), (1% GFs + 4% ZrO2), (2% GFs + 3% ZrO2), (2.5% GFs + 2.5% ZrO2), (3% GFs + 2% ZrO2), (4% GFs + 1% ZrO2) and (5% GFs + 0% ZrO2) which had the highest values. ConclusionHybrid reinforcement with GFs, ZrO2 nanoparticles, or a combination of them effectively improved flexural strength and microhardness of autopolymerizing provisional PMMA that would create provisional restorations with extended clinical service. GFs demonstrated superior reinforcing effects compared to ZrO2 nanoparticles. However, reinforcement with 2.5–5% GFs increased the surface roughness for provisional restoration.

Mechanical Properties of Three-Dimensional Printed Provisional Resin Materials for Crown and Fixed Dental Prosthesis: A Systematic Review.

The emergence of digital dentistry has led to the introduction of various three-dimensional (3D) printing materials in the market, specifically for provisional fixed restoration. This study aimed to undertake a systematic review of the published literature on the Mechanical Properties of 3D- Printed Provisional Resin Materials for crown and fixed dental prosthesis (FDP). The electronic database on PubMed/Medline was searched for relevant studies. The search retrieved articles that were published from January 2011 to March 2023. The established focus question was: "Do provisional 3D-printed materials have better mechanical properties than conventional or milled provisional materials?". The systematically extracted data included the researcher's name(s), publication year, evaluation method, number of samples, types of materials, and study outcome. A total of 19 studies were included in this systematic review. These studies examined different aspects of the mechanical properties of 3D-printed provisional materials. Flexural Strength and Microhardness were the frequently used mechanical testing. Furthermore, 3D-printed provisional restorations showed higher hardness, smoother surfaces, less wear volume loss, and higher wear resistance compared to either milled or conventional, or both. 3D-printed provisional resin materials appear to be a promising option for fabricating provisional crowns and FDPs.

Hard and soft tissue healing around teeth prepared with the biologically oriented preparation technique and restored with provisional crowns: An in vivo experimental investigation.

To evaluate the hard and soft tissues healing around teeth prepared with the biologically oriented preparation technique (BOPT) versus the chamfer technique versus non-prepared teeth. Thirty-two teeth in eight beagle dogs were randomly prepared with the BOPT (test = 16) or chamfer (control = 16) techniques and covered with polymethylmethacrylate crowns as provisional restorations. Sixteen negative controls (non-prepared teeth) were also used for comparison. Histological description and histomorphometrical measurements of the periodontal tissues were collected at 4 and 12 weeks in 7 out of 8 dogs, including the soft tissue height and thickness, and the horizontal and vertical bone dimensions. When compared with negative controls, test and control preparation techniques exhibited a more apical location of the free gingival margin with respect to the cement-enamel junction (∆ = 1.1 mm for both groups at 4 weeks (p < .05), 0.99 mm for the test group (p = .043) and 0.20 mm for control group (p = 1.000) at 12 weeks). There were no significant differences between test and control groups with respect to vertical and horizontal histometric measurements. The BOPT and chamfer tooth preparation protocols induced similar qualitative and quantitative changes in the healing of the supra-crestal soft tissue complex, when compared with non-prepared teeth. Despite the limited amount of power, it appeared that differences between the tested preparation techniques were not statistically significant.

Influence of surface treatment on repair bond strength of CAD/CAM long-term provisional restorative materials: an in vitro study

BackgroundThe surface treatment to improve the repair bond strength may vary because CAD/CAM provisional restoration polymers exhibit a variety of microstructures. This study was conducted to evaluate the effect of surface treatments on the repairability of three different CAD/CAM polymers for long-term provisional restorations.MethodsThirty specimens from each provisional restorative materials (CAD-Temp, Everest C-Temp, and PEEK) were divided into three groups: C: surfaces received no treatment; SB: surfaces were airborne particle abraded with 50 μm aluminum oxide; SB-T: surfaces received the same conditions as group SB in addition to thermocycling before and after treatment. Primer and nanohybrid repair resin composite were applied to the prepared CAD /CAM surfaces. The shear bond strength and the mode of failure were assessed. ANOVA and Tukey’s significant difference tests were used to evaluate the data.ResultsThe SB group had significantly higher repair SBS values (p < .001) compared to the other groups (C and SB-T). Everest C-Temp significantly recorded the highest repair SBS (17.84 ± 0.19 MPa) in group SB, while the lowest repair SBS values (5.51 ± 1.14 MPa) for CAD-Temp were recorded in group C. PEEK significantly recorded the second highest repair SBS (15.96 ± 0.18) in the SB group.ConclusionsEverest C-Temp had the highest repair SBS after an airborne abrasion particle. Thermocycling had no significant effect on the repair SBS for PEEK. Everest C-Temp and PEEK are recommended as long-term durable provisional materials for clinical use.

Digital implant placement accuracy: a clinical study on a fully-guided flapless single-unit immediate-loading protocol

AimsThe primary aim of the present study was to measure the discrepancy between the virtual and the actual position of the single-unit implants placed via a digitally-designed fully-guided surgical template using a flapless surgical technique. Prefabricated provisional restorations and periodontal factors were evaluated after the immediate loading of implants and 3 months after the surgery, respectively.Materials and methodsFourteen implants in nine patients were virtually planned after importing intraoral scans and cone-beam computed tomography (CBCT) records into 3D planning software. Accordingly, fully-guided surgical templates, customized abutments, and provisional restorations were designed and fabricated. The implant position after the surgery was compared with its virtual counterpart in terms of angular and apical linear deviations. Implants were immediately loaded after the surgery, and the occlusal level of the delivered provisional restorations was compared with their designed positions. Early implant failure, bleeding on probing, and peri-implant pockets were documented on the 3-month follow-up.ResultsA mean angular deviation of 5.07 ± 2.06° and a mean apical linear deviation of 1.74 ± 0.63 mm resulted. Two out of 14 implants failed within the first 3 months of the surgery, and the occlusal level difference was calculated for nine prefabricated provisional restorations.ConclusionsDIONAVI protocol has been evaluated regarding its accuracy, and an estimation of the expected deviation is presented to the clinicians using this protocol. However, before widespread use, immediate-loading protocols and provisional restorations must be studied further.Trial registrationIRCT, IRCT20211208053334N1. Registered 6 August 2022.

A fully digital workflow to register maxillomandibular relation using a jaw motion tracer for fixed prosthetic rehabilitation: A technical report.

This technique aimed to describe a fully digital workflow to register maxillomandibular relation for fixed prosthetic rehabilitation. Mandibular kinematics could be reproduced in a four-dimensional (4D) virtual patient based on the intraoral scan, facial scan, cone beam computed tomography, and jaw motion trajectory, which helped record centric relation and determine a proper occlusal vertical dimension in a virtual environment. The therapeutic position could be exported directly to the dental computer-aided design software for digital waxing design with a facial scan. The 4D virtual patient was also used to verify the functional and esthetic outcomes of provisional restorations. This novel approach digitized the process of determination, delivery, and double-check of maxillomandibular relation, thus contributing to the establishment of a completely digital workflow for fixed prosthetic rehabilitation. Registration of maxillomandibular relation, including centric relation and occlusal vertical dimension is critical to the success of prosthetic rehabilitation. Traditional procedures are complex and time-consuming, and heavily rely on the clinical experience of dentists. A fully digital approach to creating a 4D virtual patient and registering the maxillomandibular relation is established, which guides to determine a proper occlusal vertical dimension in centric relation. Digital delivery and double-check can simplify the conventional procedure and ensure that the determined maxillomandibular relation is reliable.

Trueness of the Combined Intra- and Extraoral Scanning Technique for Transferring Subgingival Contours from Provisional Restorations to Definitive Restorations

To compare the morphologic trueness of provisional and definitive restorations constructed with conventional custom impression techniques to those constructed with intra- and extraoral scanning (IEOS), which can digitally transfer the subgingival morphology of the provisional restoration to the definitive restoration. Provisional restorations were fabricated on typodonts in which implants were placed. In the conventional method, a customized impression coping was produced by using polymethyl methacrylate resin to transfer the subgingival contour of the provisional restoration. Impressions were taken with silicone impression material, and definitive restorations were made by CAM. The IEOS technique was performed as previously reported. In brief, three individually scanned stereolithography (STL) files were superimposed in CAD software to transfer the morphology of the provisional restoration to the definitive restoration. Definitive restorations were then made by CAM. The provisional and definitive restorations were both scanned by IOS. Scanned data files were superimposed with morphometry software, and the distortions were measured. Student t test was used for statistical analysis. The subgingival morphologies of definitive restorations prepared by the conventional method showed significant negative distortions compared to definitive restorations prepared by the IEOS technique. The IEOS technique can more accurately transfer the subgingival contour of provisional restorations to definitive restorations compared to the conventional customized impression coping technique.