Visible Light-cured Resin Research Articles

Ocular Prosthesis Fabrication with Visible Light-Cured Resin Custom Tray: A Case Report

A well fitting custom ocular prosthesis warrants an accurate impression of the anopthalmic socket. Problemarises when neither the stock ocular tray nor conformer is available or ill fitting in nature. This case reportelaborates the fabrication of an ocular prosthesis with emphasis on chair side method of custom ocular trayfabrication. Visible light cured resin denture base material has been used for preparation of ocular tray. Thismethod is simple, quick and precise.

可視光線重合型レジンの重合率に関する基礎的研究 : 触媒組成と重合率との関係(I)

可視光線重合型レジンの重合率に関する基礎的研究 : 触媒組成と重合率との関係(I)

可視光線重合型コンポジットレジンのフィラーに関する研究 : I. 機械的性質に及ぼす各種シリカフィラーの影響

To investigate the effect of silica fillers on the mechanical properties of visible light-cured composite resins, Bis-GMA-based composites with four types of silica fillers were prepared. The mechanical properties of the composites with splinter-shaped silica fillers increased with increasing the filler fraction. Although the spherical silica filler could be filled more with resin monomer than the splinter-shaped silica filler, the mechanical properties of spherical silica-filled composite were relatively lower than those of the composite with splinter-shaped silica fillers. The micro particle silica-filled composite showed no obvious increase in the mechanical properties in either the dry or wet conditions. SEM observations of the fractured resin surface revealed that fracture occurred through the resin matrix as well as the resin/filler interface and the mechanical properties of each composite resin were correlated with the nature of crack propagation.

Impression Making and Lab Work Authorization Forms in Fixed Prosthodontics: A Preclinical Exercise.

Making a final impression using a custom tray for fixed prosthodontics is a widely accepted procedure that is taught in many dental schools. As such, achieving competency in impression making and lab communication is a new Commission on Dental Accreditation curriculum requirement for all dental schools in the US. This resource presents an instructional slide show on the clinical steps required in fabricating a custom tray using a visible light-cured resin, making a successful impression, and writing a work authorization form for the fabrication of a fixed dental prosthesis. The presentation also contains a brief overview of alternative techniques and materials used as well as basic points for self-evaluation for the custom tray and the final impression. This activity was conducted as a small-group team-based learning exercise in a preclinical setting, where a self-assessment form was provided for students to evaluate their work. Examiners indicated that students who completed this exercise had a deeper understanding of the sequencing of steps involved in the construction of a fixed partial denture as well as better lab communication skills compared to students from previous classes who did not participate in the exercise. The preclinical setting provided students with a relaxed atmosphere for fabricating a custom tray using visible light-curing material. This exercise is part of a larger preclinical exercise that takes students through all the steps involved in the fabrication of a fixed dental prosthesis, from impression making to the evaluation of the framework made by the lab.

A randomized controlled 27 years follow up of three resin composites in Class II restorations

ObjectiveTo evaluate the durability of three conventional resin composites in Class II restorations during 27 years. MethodsThirty participants, 25 female and 5 male (mean age 38.2 years, range 25–63), received at least three (one set) as similar as possible Class II restorations of moderate size. The three cavities were chosen at random to be restored with a chemical-cured (Clearfil Posterior) and two visible light-cured resin composites (Adaptic II, Occlusin). A chemical-cured enamel bonding agent (Clearfil New Bond) was applied after Ca(OH)2 covering of dentin and enamel etch. Marginal sealing of the restorations was performed after finishing. One operator placed 99 restorations (33 sets). Evaluation was performed with slightly modified USPHS criteria at baseline, 2, 3, 10 and 27 years. ResultsPostoperative sensitivity was observed in 5 patients. Three participants with 11 restorations (11%) could not be evaluated at the 27 year recall. Thirty-seven restorations failed (13 AII, 10 CP and 14 O). The overall success rate after 27 years was 56.5% (AII 55.2%, CP 63.0%, O 51.7%; p=0.70), with an annual failure rate of 1.6%. The main reason for failure was secondary caries (54.1%), followed by occlusal wear (21.6%) and material fracture (18.9%). Non-acceptable color match was seen in 24 (28.3%) of the restorations (AII 2, CP 16, O 6). Cox regression-analysis showed significant influence of the covariates tooth type, caries risk, and bruxing activity of the participants. ConclusionsClass II restorations of the three conventional resin composites showed an acceptable success rate during the 27 year evaluation.

Single Day Complete Denture Using Triad Visible Light Cured (VLC) Resin -A Case Report

A technique is described for construction of complete denture in one appointment using visible light-cured resins. Conventional denture therapy is a physical and psychological trauma for geriatric, medically and physically compromised patients as it requires multiple visits. Also conventional heat cure denture includes hypersensitivity (residual monomer) and increased porosity as added disadvantages. This alternative treatment not only reduces laboratory, dentist, and patient's time but also reduces the porosity and tissue hypersensitivity as it is a monomer free denture. An added advantage is that it gives psychological satisfaction and provides good aesthetic as teeth placement is done directly in the mouth.

Development of a Three-Dimensional Slurry Printing System Using Dynamic Mask Projection for Fabricating Zirconia Dental Implants

This study aims to develop a three-dimensional slurry printing system (3DSP) and to use a two-stage sintering process for the fabrication of zirconia dental implants. Solvent-soluble slurry which is composed of zirconia powder, visible light-curable resin, and methanol is prepared. During layer casting, the liquid slurry penetrates into the pores of the subjacent layers. The fresh layer and the subjacent layer tightly connect when the solvent dries. The mask pattern for the sliced layers is then exposed on a solvent-soluble slurry, for solidification and to form the green part that is embedded in the green block, layer-by-layer. The green block is immersed in a methanol solution, which causes the collapse of the un-exposed part. As a result, the rigid green part is obtained. Two-stage sintering is used to heat the rigid green part to 600°C to produce binder burnout and to 1450°C to sinter the zirconia dental implant part. The results show that sintered parts have an average flexural strength and micro-hardness of 539.1 MPa and 1556 HV, respectively. The zirconia dental implant is successfully fabricated using the 3DSP system developed. The proposed fabrication method using a 3DSP system is briefly described and it is proven that there is a good capacity to fabricate zirconia dental implants.

Randomized clinical evaluation of a light-cured base material for complete dentures

The purpose of this study was to compare plaque adhesion, tissue reaction, and technical complications for complete dentures based on visible light-cured resin (VLCR) or on conventional poly(methyl methacrylate) (PMMA). A stratified randomized cohort study was designed with 52 patients treated with a complete denture in the maxilla (n = 28), the mandible (n = 2), or both (n = 22). Seventy-four dentures were manufactured, 38 of PMMA and 36 of VLCR. Investigators and patients were unaware of the nature of the denture base material. Plaque adhesion, tissue reaction, and technical complications were investigated 4 weeks after denture insertion (baseline). Recall investigations were performed after 6, 12, and 24 months. After 6, 12, and 24 months, plaque adhesion was significantly higher for VLCR dentures than for PMMA dentures. Tissue reaction was comparable for both groups, however. After 6, 12, and 24 months, need for repair was significantly greater for VLCR prostheses. The mean number of additional aftercare sessions per patient after 24 months was 50 % higher for VLCR than for PMMA. Good oral hygiene must be established by patients treated with VLCR dentures, to remove biofilm from these dentures. Increased aftercare must also be taken into account when this material is used. VLCR might be a viable alternative to PMMA for patients with allergic reactions to residual monomer or benzoyl peroxide.

A novel fabrication method of high strength alumina ceramic parts based on solvent-based slurry stereolithography and sintering

The aim of this paper is to develop a novel Solvent-based Slurry Stereolithography and Sintering (4S) process which can fabricate high strength ceramic parts. High performance solvent-based slurry, which was composed of alumina powder as a structure material, visible light curable resin as an organic binder and methanol as a solvent and a dispersant, could be prepared with colloidal processing. During layer casting, the diaphanous slurry can penetrate into pores of the subjacent layers. After drying, the binder in the penetrated liquid could connect the fresh layer and subjacent layers. Eventually, a gel-like green block could be built layer by layer. In the exposed region, the resin contained in the green block was cured to connect the alumina powders to be a part of the rigid green part. However, the un-exposed region remained gel-like and is methanol-soluble. Afterward, the green block was immersed in a methanol solution. Due to dissolving of the resin, the un-exposed region could completely collapse to obtain the rigid green part. The obtained rigid green part was then heated up to 600°C for binder burnout, and then sintered at 1600°C to obtain a dense alumina ceramic part. The results show an average tensile and flexural strength are 327 and 472 MPa, respectively, and a relative density of 98% was achieved. The proposed method of solvent-based slurry was briefly described and it was proved that the good capacity of solidifying thin layer. The results also show that the developed system can fabricate complicated rigid green parts quickly with high accuracy (less than 5 μm).

Clinical performance of a light-cured denture base material compared to polymethylmethacrylate—a randomized clinical study

The aim of this study was to evaluate the clinical long-term performance of a visible light-cured resin (VLCR) denture base material and to compare it to a well-established polymethylmethacrylate (PMMA)-based denture acrylic in a randomized split-mouth clinical long-term study. One hundred removable partial dentures in 90 patients, with at least two saddles each, were investigated. One saddle was made of VLCR, while the other was made of PMMA at random. Plaque adhesion, tissue reaction, and technical parameters of the dentures were assessed 6, 12, and 18 months after treatment. Statistical analysis was performed using the Wilcoxon rank-sum test. Though VLCR showed higher plaque adhesion than PMMA after 6, 12, and 18 months (p < 0.001), there were no important differences with regard to tissue reaction. Concerning plaque adhesion, surface quality with regard to the lower side, interfaces between denture acrylic and metal and the boundary between denture acrylic and denture tooth PMMA was rated higher than VLCR. The surface quality of the upper side of the denture saddles showed no significant differences (p > 0.05). Neither VLCR nor PMMA showed discoloration at any point in time (p > 0.05). It can be concluded that VLCR is a viable alternative for the production of removable dentures. Especially in patients with hypersensitivities to PMMA, VLCR is particularly suitable for clinical use.

A Study on Effect of Surface Treatments on the Shear Bond Strength between Composite Resin and Acrylic Resin Denture Teeth

Visible light-cured composite resins have become popular in prosthetic dentistry for the replacement of fractured/debonded denture teeth, making composite denture teeth on partial denture metal frameworks, esthetic modification of denture teeth to harmonize with the characteristics of adjacent natural teeth, remodelling of worn occlusal surfaces of posterior denture teeth etc. However, the researches published on the bond strength between VLC composite resins and acrylic resin denture teeth is very limited. The purpose of this study is to investigate the effect of five different methods of surface treatments on acrylic resin teeth on the shear bond strength between light activated composite resin and acrylic resin denture teeth. Ninety cylindrical sticks of acrylic resin with denture teeth mounted atop were prepared. Various treatments were done upon the acrylic resin teeth surfaces. The samples were divided into six groups, containing 15 samples each. Over all the treated and untreated surfaces of all groups, light-cured composite resin was applied. The shear strengths were measured in a Universal Testing Machine using a knife-edge shear test. Data were analyzed using one way analysis of variance (ANOVA) and mean values were compared by the F test. Application of bonding agent with prior treatment of methyl methacrylate on the acrylic resin denture teeth resulted in maximum bond strength with composite resin.

Flexural properties of repaired heat‐polymerising acrylic resin after wetting with monomer and acetone

Repair strength can be improved by treating fractured surfaces of a denture. This study investigated flexural properties of heat-polymerised acrylic resin specimens repaired with auto-polymerising and visible light curing (VLC) resins after the repair surfaces were wetted with monomers or acetone. Fifty-four specimens (65 x 10 x 2.5 mm) were prepared and 48 of them were sectioned to simulate denture fracture. Butt-joint designed repair surfaces were wetted with heat-, auto-polymerising monomers and acetone for 180 s and repaired with auto-polymerising and VLC resins. After repairs, specimens were subjected to three-point bending test and flexural strength, strain, fracture load, modulus of elasticity and deflection values were recorded. Data were analysed with Student t and LSD tests (p < or = 0.05). Overall flexural strength, strain, fracture load and deflection values of specimens repaired with VLC resin were significantly higher than the specimens repaired with auto-polymerising resin for all types of wetting agent (p < 0.05). Within the wetting agents, heat- and auto-polymerising monomers produced the best mechanical properties, while wetting with acetone did not provide superior effect over both monomers. In clinical use, wetting the repair surfaces may result in stronger repairs. The use of bonding agent in VLC resin repairs in combination with wetting agent results in improved flexural properties.

Comparative study of the fatigue strength of five acrylic denture resins

The aim of this in vitro study was to compare the fatigue resistance of three kinds of heat-polymerized acrylic resins (conventional heat-polymerized, rapid heat-polymerized, high impact acrylic resin), a kind of visible light-cured resin and a kind of self-cured acrylic resin. A total of 60 notched and un-notched specimens (65 mm × 10 mm × 3 mm) were fabricated, 12 from each material. The fatigue resistance was measured by applying repeated three-point bending deflection to the specimens. For statistical analysis, Kruskal–Wallis test followed by Dunn’s multiple comparison tests were used. The Kruskal–Wallis test revealed significant differences in the fatigue resistance among some groups ( p < 0.05 ). Conventional- and rapid-heat polymerized resins had lower fatigue resistance values than heat-polymerized high impact acrylic resin, but the differences were statistically non-significant according to Dunn’s test ( p > 0.05 ). High impact acrylic resin was also found to have significantly higher fatigue resistance value than that of self-cured resin and light-cured resin ( p < 0.05 ). Further, there was no statistically significant difference between the mean fatigue resistance value of visible light-cured resin and self-cured resin ( p > 0.05 ).

Influence of Background Color on the Chromatic Value of Four All-Ceramic System Core Materials

This study aims to investigate the effect of background color on the chromatic value of four all-ceramic system core materials at clinically appropriate thicknesses. Disc specimens with 15 mm in diameter and thicknesses ranging from 0.5±0.01mm In-Ceram zirconia core, Cercon base zirconia core, and Cercon base color zirconia core) to 0.8±0.01mm (Empress II) were fabricated. A colorimeter (CIE- 1976-Lab) measured the chromatic value of all samples placed on a high-noble metal-ceramic alloy and a visible light-cured dental composite resin (A2 color) background, after which the color difference was calculated. The color difference of Empress II samples was more than 1.5 among different background color groups, while that of Zirconia was less than 1.5. The influence of background color on the Empress II dentin was visible, such that it could be used on a tooth color post. Meanwhile, the influence of background color was invisible for the three kinds of Zirconia core materia1s, such that the materials developed excellent color-masking abilities and could be adapted for use on any color background.

Accelerating fabrication speed in two-laser beam stereolithography system using adaptive crosshatch technique

The aim of this research is to develop a novel two-laser beam stereolithography system. The wavelengths of the two semiconductor laser beams are determined to be 405 nm (blue light) and 532 nm (green light), respectively, according to the relative absorbance rate of used visible light curable resin. The blue light laser is suitable for scanning contour of objects because of its fast absorbance, thus giving a narrow cured depth. The green light laser is better suited for scanning the internal crosshatch for condensing the fabrication time because its high power results in a wide cured width and deep penetration. The influence of the photoabsorber, carbon powder with average diameter of 0.1 µm, is discussed and an optimal weight percentage of 1.5 is specified for controlling cured thickness. An adaptive crosshatch technique is introduced and applied to the fabrication process. In addition, a turbine is fabricated using the proposed approach for comparison with the E-DARTS system in terms of fabrication capability. Results show that the developed system can fabricate objects quickly with high accuracy.

Intraoral Acrylic Resin Coping Fabrication for Making Interocclusal Records

A safe and accurate method for the fabrication of acrylic resin copings to be used for interocclusal registration is described. Copings are fabricated on vital prepared teeth using visible light-cured acrylic resin, and the records are then obtained with autopolymerizing acrylic resin. This allows for an interocclusal recording to be obtained at the final impression appointment.

A comparative study to evaluate the effect of fluoride releasing sealant cured by visible light, argon laers, and light emitting diode curing units: An in vitro study

In Pediatric Dentistry, the use of pit and fissure sealant is one of the essential forms of prevention. Pit and fissure caries may be substantially decreased by obliteration of these developmental defects in occlusal, buccal and lingual surfaces with resin based dental sealants. Visible light-curing units, or LCUs, are an integral part of modern adhesive dentistry" They are used to cure resin based composite restoration materials, resin modified glass-ionomer and pit and fissure sealants, as well as to bond orthodontic teeth. Most recently, the argon laser has been approved for initiating the setting reaction with visible light cured-resins. Argon curing of resin materials has been show to enhance the physical properties and degree of polymerization of the resin, while reducing the polymerization time by 75 percent. The study is undertaken considering the inadequate research reports of regarding the comparison of curing ability using argon laser. LEDs and visible light as well as the resistant towards caries activity of the preventive fluoride releasing pit and fissure sealant cured by above mentioned curing units.

Fabricating a Hollow Obturator with Visible Light‐Cured Resin System

Obturators are routinely used in the rehabilitation of maxillectomy defects. Ideally, obturators should be easily constructed to produce a comfortable and stable prosthesis. This article describes a technique that provides an easy method for the construction of an obturator prosthesis using a visible light-cured (VLC) resin. As a result, technicians can easily construct obturators in little time; this would, in turn, provide patients with light, comfortable, and tolerable prostheses.

Diametral Tensile and Compressive Strengths of Several Types of Core Materials

Compressive and diametral tensile strengths (DTSs) of core materials are thought to be important, because cores usually replace a large bulk of tooth structure and should provide sufficient strength to resist intraoral tensile and compressive forces. This study was undertaken to compare the mechanical properties of materials used for direct core foundations. The differences between the compressive and DTSs of six core materials, including Duralloy (high-copper amalgam), Grandio (visible light-cured nanohybrid resin composite), Admira (organically modified ceramic), Filtek P60 (packable composite resin), Rebilda DC (dual-cure adhesive core material), and Argion Molar (silver-reinforced glass ionomer cement), were tested. A total of 120 specimens, half for the compressive strength (CS) test (6 mm in height, 4 mm in diameter) and the other half for the DTS test (6 mm in diameter, 3 mm in thickness), were prepared. The specimens were stored at room temperature in distilled water for 7 days. The Lloyd testing machine was used to load the specimens at a crosshead speed 0.5 cm/min, and the strength values were determined in MPa. The compressive and DTS test values (in MPa), respectively, of the materials were: Admira (361, 44); Filtek P60 (331, 55); Grandio (294, 53); Rebilda DC (279, 42); Duralloy (184, 40); and Argion Molar (107, 9). Kruskal-Wallis test was computed, and multiple comparisons test discerned many differences among materials (p < 0.05). Packable composite resin (Filtek P60), visible light cured nanohybrid resin composite (Grandio), and organically-modified ceramic (Admira) had higher compressive and DTS values than the other materials.

Effect of chemical surface treatments and repair material on transverse strength of repaired acrylic denture resin

This study was performed to evaluate the transverse strength of a denture base resin (H), repaired with an autopolymerizing acrylic resin (A) or a visible light-curing (VLC) resin (T) following the use of three chemical solvents: methyl methacrylate monomer, aceton or chloroform. Eighty specimens (65.0 x 10.0 x 3.3 mm) of H were fabricated and stored in distilled water at 37 degrees C for seven days. Specimens were divided into eight equal groups of 10. In each group, specimens were sectioned in the middle to create a 10 mm gap. Two groups served as controls and had no surface treatment. They were repaired with A or T materials. In the remaining six experimental groups, specimen surfaces were treated with ac for 30 sec or mma for 180 sec or ch for 5 sec. Then A or T material was placed on the treated surfaces, using the same preparation molds. After seven days' storage at 37 degrees C, the transverse bond strength (MPa) of the specimens was measured using a three-point bending test. A two-way ANOVA and a Tukey HSD were performed to identify significant differences ( P < 0.05). The nature of the failures was noted as adhesive, cohesive or mixed. Significant differences were found between the controls and experimental groups ( P < 0.05). In the control groups, repair with A showed significantly higher strength (60.3 MPa) than those repaired with T (51.3 MPa). Mean transverse strength of experimental specimens repaired with A was (75.06 MPa) which was significantly greater than those repaired with T (67.9 MPa). Although surface treatment increased repair strength, no significant differences were detected between the effects of the chemical etchants. The autopolymerizing resin exhibited significantly higher repair strength than VLC resin. The transverse strength of the repaired specimens was increased significantly after chemical treatments.