Direct Resin Research Articles

Enhancement of dentin bond strength of resin cement using new resin coating materials.

The purpose of this study was to investigate combinations of resin coating materials with a dual-cure resin cement for indirect restorations by evaluating microtensile bond strengths (μTBS). Dentin surfaces of human molars were bonded with either a direct or an indirect resin composite with/without the resin coating technique. For the resin coating material, Clearfil SE Bond 2 and either one of Clearfil Protect Liner F, Clearfil Majesty LV, Panavia V5 or an experimental light-cure coating material were used. For the dual-cure resin cement, either Panavia V5 or Panavia F2.0 were used with Panavia V5 Tooth Primer or ED Primer II. Resin coating does not always contribute to the enhancement of μTBS. The highest μTBS was obtained with the resin coating combination of Clearfil SE Bond 2 and Panavia V5, and cementation with Panavia F2.0, which was identical to that of the direct resin composite bonded with Clearfil SE Bond 2.

Long-term clinical evaluation of direct resin composite restorations in vital vs. endodontically treated posterior teeth — Retrospective study up to 13 years

ObjectivesThis retrospective study evaluated and compared the survival rate of Class II posterior direct resin based composite (RBC) restorations made in vital teeth (VT) and endodontically treated teeth (ETT). The influence of risk factors on the long-term performance of restorations was also investigated. MethodsPatients (n=245) receiving RBC posterior restorations between 2004 and 2012 were selected. A total of 597 restorations (485 in VT, 112 in ETT) with minimum 2.5–3mm remaining cusp thickness, made with the same brand of RBC and adhesive, were evaluated using the USPHS criteria. Data were analyzed with Mann–Whitney, Chi-square and Fisher’s Exact Test, Extended Cox-regression and Kaplan–Meier analysis (p<0.05). Relative risk ratio was estimated for each evaluated parameter. ResultsThe mean observation period was 8.6±2.3 years. An annual failure rate in VT and ETT of 0.08% and 1.78%, respectively, was detected. The reasons of failures included restoration fracture, secondary caries in VT; vertical root fracture, cusp fracture, restoration fracture, secondary caries and loss of adhesion in ETT. Significantly better performance was observed in RBCs of VT for each evaluated parameter. Among the evaluated risk factors only occlusal stress affected negatively the survival of RBC in ETT (Hazard Ratio 37.1; CI95% 8.4–163.7). SignificanceAlthough, there is significant difference in the success rate of RBCs in VT (98.97%) and ETT (76.8%), the long-term (6–13 years) durability of Class II RBCs with 2.5–3mm cusp thickness in ETT is also clinically acceptable. The presence of occlusal stress decreases the survival of RBCs in ETT.

Impact of restorative treatment of tooth wear upon masticatory performance

ObjectiveThe restorative treatment of generalized tooth wear involves an increase in vertical dimension of occlusion and a comprehensive alteration of occlusal morphology. The aim of this study was to assess the impact of a direct adhesive restorative treatment on masticatory performance parameters. Materials and methodsA sample of 23 fully dentate adult generalized tooth wear patients (17 male, 6 female, age 41.7 ± 8.3 years) undergoing direct composite restorative treatment was selected. Before and one month after restorative treatment with resin bonded composite restorations, masticatory performance was evaluated using 1) a comminution test, 2) a maximum voluntary bite force recording and 3) the sum score of five items related to eating and chewing from the Oral Health Impact Profile (OHIP-49) questionnaire. Statistical analysis was performed using a paired t-test, and analysis per OHIP item was done by a McNemar test (p < 0.05). ResultsThere was no statistically significant difference in median particle size (X50) calculated before and after treatment (4.19 ± 0.97 and 4.03 ± 0.76, respectively, p = 0.327). Maximum voluntary bite force decreased significantly after treatment (baseline 389 ± 90 N, one month recall 323 ± 173 N, p = 0.028). The sum score of the five OHIP items significantly decreased after treatment (baseline 10.6 ± 4.8, one month recall 6.6 ± 2.5, p = 0.001), with the item regarding unsatisfactory diet showing the largest significance (p = 0.029). ConclusionsThis study indicates that the restorative treatment of generalized tooth wear using direct resin bonded composite has no significant short-term effect on masticatory performance as measured with a comminution test, although the self-reported ability to eat and chew, as measured by the sum score of all pertaining OHIP items, did significantly improve. Clinical significanceOn individual level, food comminution could be influenced by restorative treatment with increase of vertical dimension of occlusion, but at group level no significant effect is observed. Nevertheless, tooth wear patients do perceive improved ability to eat and chew foods, which is clinically relevant.

Simple and Low-Cost Thermal Treatments on Direct Resin Composites for Indirect Use.

The aim of this study was to evaluate the influence of three low-cost additional thermal treatments, available in the dental office, on the mechanical, chemical and optical properties of a light-cured resin composite indicated for direct restorations but used as indirect restorative. The direct resin composite TPH3 (Dentsply) was light-polymerized using a light-emitting diode curing unit and submitted to three experimental additional thermal treatments: dry heat at 170 °C for 5 min, autoclave at 121 °C for 6 min, or microwave oven at 450 W for 3 min. The resin composite without any thermal treatment was used as negative control group. An indirect resin composite (Vita CM LC, Vita Zahnfabrik) was tested as a reference. Flexural strength, elastic modulus, microhardness, degree of C=C conversion, roughness before and after simulated toothbrush abrasion, translucency parameter and color difference (ΔE00) were evaluated. Data were analyzed at α=0.05. The indirect resin composite presented lower C=C conversion and mechanical performance. The flexural strength was significantly higher in the dry oven group compared with the control. The roughness was not different among groups before or after brushing, but the thermal treatments caused an increase in C=C conversion, microhardness, and elastic modulus without affecting the translucency parameter or showing visible color alteration (ΔE00<1.8). These results suggest that the use of additional thermal methods of polymerization represents an economical and simple alternative to enhance the mechanical and chemical properties of direct resin composites when used as indirect restoratives.

Repair bond strength of resin composite to restorative materials after short- and long-term storage

ObjectivesTo investigate short- and long-term bond strength (“repair bond strength”; RBS) of a resin composite to six restorative materials using either a silane and a bonding agent or a universal “one-step self-etch” adhesive system. MethodsSpecimens were produced from an amalgam, a direct resin composite, two indirect resin composites, a hybrid ceramic, and a feldspar ceramic and stored for 3 months in tap water (37 °C). All specimens were then sandblasted (Al2O3; 25 μm) and either treated with Monobond Plus and OptiBond FL Adhesive (MP-OFL) or with Scotchbond Universal (SBU). Filtek Z250 was used as “repair composite”, and RBS was measured by means of a micro shear bond strength test after 24 h or after 1 year. RBS values (n = 15/group) were statistically analyzed (α = 0.05). ResultsRBS (MPa; mean values (standard deviations)) after 24 h for MP-OFL: 18.6 (3.2)–23.9 (5.0) and for SBU: 12.5 (4.9)–18.1 (4.6); after 1 year for MP-OFL: 8.9 (4.6)–19.8 (4.3) and for SBU: 5.6 (2.3)–18.8 (3.5). After 24 h, MP-OFL showed significantly higher RBS to the hybrid ceramic and the feldspar ceramic than did SBU (p ≤ 0.0001) whereas there was no significant difference in RBS for the other four restorative materials. After 1 year, MP-OFL showed significantly higher RBS to the feldspar ceramic than did SBU (p = 0.043) whereas there was no significant difference in RBS for the other five restorative materials. SignificanceThe use of a silane and a bonding agent seems more versatile for repairing restorations than the use of a universal “one-step self-etch” adhesive system.

Fatigue and fracture resistance of minimally invasive ceramic and resin composite veneers with different designs bonded adhesively to severely eroded teeth

This study evaluated the load bearing capacity of minimal invasive restoration alternatives on severely worn teeth after cyclic loading. Sound human maxillary incisors (N = 72, n = 9 per group) were randomly divided into nine experimental groups to receive one of the following restoration types: Group 1: Intact tooth, Group 2: Direct resin composite, Group 3: Lingual: Indirect resin composite, Labial: Ceramic veneer with lingual overlap, Group 4: Lingual: Indirect resin composite with lingual overlap, Labial: Ceramic, Group 5: Lingual: Direct composite, Labial: Ceramic, Group 6: Lingual: Feldspathic Ceramic, Labial: Feldspathic ceramic, Group 7: Lithium disilicate crown, Group 8: Metal-ceramic crown. Teeth were prepared simulating erosion/wear conditions. Specimens were subjected to cyclic loading (1,200,000 cycles, 5–55 °C) and then loaded to failure from the lingual surface at 105° inclination (1 mm/min). Data (Newton) were analyzed using one-way ANOVA, Tukey`s tests and Weibull moduli were calculated (α = 0.05). Significant differences were observed between the groups for the initial (p = 0.006) and maximum fracture load (p = 0.002). Group 3 (55 ± 36) presented significantly lower initial fracture load compared to other groups (79 ± 35–134 ± 36) (p < 0.05). When maximum fracture load is considered, control group (1) (602 ± 355) and from restored groups 2 (449 ± 144) and 4 (495 ± 291) showed significantly higher results (p < 0.05). Weibull modulus for the maximum fracture load was the highest for Group 2 (m = 3.47) among all groups (m = 1.61–4.18). Groups 2, 3, 6 presented the highest incidence of repairable failures. Based on the results, severely worn teeth could be restored with lingual direct resin composite and labial veneering with indirect resin with overlap.

Form ever follows function: the occlusal compass and direct resin composite restorations

Direct composite resins in the posterior dentition are a day-to-day treatment modality for most dental practitioners. It is challenging for many operators to produce a restoration that is both aesthetic and functional in a clinically realistic timeframe. This article helps to address this. CPD/Clinical Relevance: To present a functionally-generated approach to occlusal anatomy based on the DeVreugd Occlusal Compass to simplify the placement of direct composite resin in the Class I and II situation.

Effect of different repair protocols on the micro-shear bond strength of different repair materials to indirect co posite blocks

Aim: This study was carried out to investigate the effect of some surface treatment protocols on bond strength of different types of composites to indirect composite blocks at different aging periodsMaterials and methods: One hundred and eight discs were obtained from indirect esthetic restorative blocks (Grandio Blocs, VOCO GmbH, Germany) which are designed for Cerec CAD/ CAM system, shade A2, size 14. Three millimeters thick discs were obtained by sectioning the blocks using a low speed isomet saw (Isomet 1000, Buehler Ltd., Lake Bluff, IL, USA). The discs were divided into six groups (18 each) according the surface pre-treatment employed. Group 1: no treatment as control, group 2: roughening with diamond stone, group 3: sandblasting and silica coating. Group 4: etching with phosphoric acid 30% for one minute, group 5: combination of roughening and etching and group 6: combination of sandblasting and etching. Each group was further subdivided to three subgroups (6 each) according to the repair material used either nanohybrid composite, bulk fill composite and organically modified ceramic restorative material (Ormocer). Finally each subgroup was divided into two classes (3 each) according to the aging time either 24 hours or 3 months. After surface treatments, Futurabond U (VOCO GmbH, Cuxhaven, Germany) was applied. Before curing, small cylinders were cut from tygon tubes (Norton Performance Plastic Co. Cleveland of USA) with an internal diameter of 0.8 mm and a height of 1 mm. Five cylinders were mounted on the treated surfaces of each disc (n = 30). Finally, the adhesive was light cured for 20 seconds using LED light curing unit. Three repair materials were used in this study. Nano-hybrid resin composite (Grandio) shade A2, regular bulk fill resin composite (x-tra fil) universal shade and organically modified ceramic restorative material (Ormocer) (Admira Fusion). All materials used were of the same manufacturer (VOCO GmbH, Cuxhaven, Germany). Each material was packed into the cylinder lumen using endodontic plugger and light-cured for 20 seconds using the same light curing unit. For the three-month group, the specimens were stored for three months in distilled water at room temperature. Using a universal testing machine (Llyod instruments Ltd, fareham UK), the μ-SBS were measured. A wire of 0.2mm diameter was looped around the resin composite cylinder. Shear force was applied to each specimen at a cross-head speed of 0.5 mm/min until failure occurred. Results: Regarding 24-hour storage time, One-way ANOVA and post-hoc Tukey’s HSD test showed that within Nanohybrid group, Bulk fill group and Ormocer group; Group 6 had the significantly highest µSBS. While Regarding three months storage time, One-way ANOVA and post-hoc Tukey’s HSD test showed that within Nanohybrid group, Bulk fill group; Group 6 had the significantly highest µSBS. Within Ormocer group; Group 5 had the significantly highest µSBS. There were no significant differences in µSBS detected between the different repair material within each surface treatment group Independent Student-t test revealed that within all study groups, µSBS mean values at 24-hour storage time were significantly higher than those of 3-month ageing time (P 0.05).Conclusions: Within the limitation of this invitro study the following conclusions could be drawn: 1- Combination of surface treatment protocols significantly increased the repair bond strength. 2- There was no difference between the three direct resin composite materials on repairing the composite blocks after 24 hours. 3- The bond strength of the repaired composite blocks after 24 hours storage showed higher micro-shear bond strength than after 3 months aging.

Direct Restorations, Endodontics, and Bleaching: Materials and Techniques Used by General Dentists of New Zealand.

Background To investigate the selection and use of direct restorative materials, endodontic techniques adopted, and approaches to bleaching by general dentists in New Zealand. Methods A questionnaire comprising 19 sections and 125 questions was distributed via mail to 351 general dentists in New Zealand who were selected, at random, from the Dental Council of New Zealand's 2016 register. Results A total of 204 questionnaires were returned, of which 188 were usable. Direct resin composite was the most commonly used material for occlusoproximal cavity restorations in premolars (93.7%) and permanent molars (85.2%). Resin-modified glass ionomer cements (34%) and resin composite materials (31.4%) were more commonly used in the restoration of deciduous molars. Home-based vital bleaching was provided by a significant number of dentists (86%), while only 18% provided practice-based bleaching. Cold lateral condensation was the most commonly used obturation technique (55.8%), and 83% of respondents reported using rubber dam for treatments. Conclusions The findings from this study indicate that dentists in New Zealand are adapting to new materials and technologies to provide high quality care to their patients. Aesthetic treatments such as bleaching have become an integral part of general dental practice.

Dental practice in the UK in 2015/2016. Part 3: aspects of indirect restorations and fixed prosthodontics.

This paper reports data which helps identify changes and trends in the provision of indirect fixed prostheses in general dental practice in the UK. To determine by means of an anonymous, self-report questionnaire, the current trend in the provision of fixed prosthodontic treatments, with a special emphasis on the choice of treatment modalities, techniques and materials. The data presented were extracted from the data obtained from a validated,121-question questionnaire distributed at random to general dental practitioners in the UK attending postgraduate meetings in 2015/2016, with a wide distribution of locations. A response rate exceeding 66% was achieved. Amalgam and light-cured composite were the preferred material for core build-up of vital teeth for around 62% of the respondents. Dentine pins were still being used by 66% of the respondents. The vast majority of respondents (92%) used a post and core to restore root-treated teeth. Fibre posts were the most commonly used (63%) type of preformed post among the respondents. Using the opposing and adjacent teeth as a reference to control tooth structure reduction during vital tooth preparation was the most common method, used by 42% of the respondents. Addition-cured silicone impression materials were the most frequently used impression material (78%). The surveyed practitioners were equally split between precious and non-precious metals as the substructure for indirect restorations. Glass-ionomer luting cements (47%) and resin-based cements (52%) were the most commonly used to cement porcelain fused to metal and zirconia indirect restorations, respectively. Laboratory made aesthetic veneers were prescribed by half of the respondents, while a third of them preferred direct resin composite as a veneer material. Within the limitations of the study, it was concluded that there has been an increase in the use of adhesive bonding and metal-free restorations. Amalgam and dentine pinscontinued to be used, contrary to international trends. Studies of the type reported are considered important in investigating trends and developments in dentistry.

Indirect Restorations and Fixed Prosthodontics: Materials and Techniques Used by General Dentists of New Zealand.

Background To investigate the selection and use of materials and techniques for core buildup, indirect restorations, and fixed prosthodontics by general dentists in New Zealand. Methods A questionnaire comprising 19 sections and 125 questions was distributed via mail to 351 general dentists in New Zealand who were selected from the Dental Council of New Zealand's 2016 register. Results The majority of the respondents (68.8%) reported using resin composite light-cured materials for the core buildup of vital posterior teeth. A large number of respondents (52%) did not use dentine pins, with the majority of them (25%) being recent graduates (<10 years). Fibre posts were used by 61.6% of the dentists surveyed. The majority of dentists (54.6%) reported using addition-cured silicone impression material for crown and bridge impressions. Glass-ionomer cements (37.5% of participants) and resin-modified glass-ionomer cements (35.8%) were the most common luting cements used. Direct resin composite veneers were the preferred material of choice rather than indirect restoration of anterior teeth (40.4%). Conclusions The study showed that New Zealand dentists surveyed are using current state-of-the-art materials and techniques, with their choice of material being greatly influenced by clinical indications and patients aesthetic demands.

Wear of direct resin composites and teeth: considerations for oral rehabilitation.

Little is known about the wear rate of enamel and dentin opposing resin composite following restoration of the occlusal surface in patients with tooth wear. Hence, the aim of this invitro study was to evaluate the wear of enamel and dentin surfaces when opposing each of three resin composites in a two-body and three-body wear test. The two-body and three-body wear of dentin, enamel, and three resin composites (Clearfil AP-X, Filtek Z250, and Filtek Supreme) opposing four antagonists (stainless steel and three resin composites) were evaluated using the ACTA wear machine. In addition, all the surfaces were evaluated with scanning electron microscopy. The results showed the lowest wear rate in enamel and the highest in dentine, with the composite showing intermediate wear rates. The three-body wear results were not affected by the antagonist and showed pure wear caused by the abrasive food medium. The invitro enamel/composite wear ratio was 2.5. The results show that tooth wear accelerates as soon as enamel disappears and dentin is exposed to composite resin. Therefore, it is important to protect dentin with a restorative material.

Repair potentiality of CAD/CAM composite block and hybrid ceramic block by direct resin composite restoration with and without surface treatment

Objective: to evaluate microshear bond strength of CAD/CAM composite block and hybrid ceramic block repaired by direct resin composite restoration with and without surface treatment.Materials and Methods: Two different CAD/CAM restorative materials were tested in the present study: hybrid ceramic blocks (Vita Enamic) and resin composite blocks (Grandio). Six sections were prepared from each CAD/CAM blocks. The sections from each block type were randomly divided into three groups according to the surface treatment performed. Control group: the specimens were ground with a grinding machine. Etching gel Group: 37% phosphoric acid etching gel was applied occlusally on the surface of the section and CoJet Group. the surface of all groups were then silanized using Bis-Silane then bonding agent Futura bond DC was applied. A polyethylene micro tubes were prepared that were held in place with a tweezer on the uncured then light cured for 10 seconds Resin composite (Grandioso X-tra) was packed inside the microtubes and light cured. All specimens were prepared by the same operator at 22.0–22.5 ˚C (room temperature) and relative humidity of 50%. The specimens were further divided into two groups according to storage conditions. Half of the specimens were thermocycled in distilled water for 5000 cycles in a 5–55˚C water bath with a dwell time of 30 seconds and a transfer time of 5 seconds. The other specimens were stored in distilled water for 2 days. Microshear bond strength was performed and fractographic analysis to determine the failure mode. Statistical analysis was then performed using a commercially available software program (SPSS 19; SPSS, Chicago, IL, USA). As data were not normally distributed, significance of the difference between different groups within the same surface pretreatment was evaluated using Kruskall Wallis test. Mann Whitney U test was used for pairwise comparisons and to study the effect of surface pre-treatment. The interaction of restoration and type of pretreatment variables was evaluated using 3 ways ANOVA. The level of significance was set at P < 0.05.Results: Three ways ANOVA test revealed that each of the material type (composite/hybrid ceramic), the subgroup type group (control/etching/Cojet) and the thermocycling (Yes/No) variables resulted in a statistically significant difference (p=0.00, p=0.00, p=0.003 respectively). Interaction of the subgroup (control/etching/Cojet) variable with the thermocycling (Yes/No) variable and the material (composite/hybrid ceramic) variable showed a statistically significant difference (P=0.023, p=0.001 respectively). Moreover, interaction of thermocycling and material variable resulted in a significant difference (p=0.034). However, interaction of the 3 study variables (material, subgroup, thermocycling) was not statistically significant (p=0.165). The failure mode of the tested specimens analyzed using Scanning Electron Microscope at magnification 80X was commonly mixed type of failure (adhesive failure between resin composite restoration and CAD/CAM blocks with cohesive failure within resin composite restoration).Conclusions: Grandio composite blocks is very promising materials and their optimum long lasting repair potentiality that offers to the clinicians great chance to easily repair the defective restoration with safety. Surface treatment using Phosphoric acid or Cojet system greatly improve the bond strength between composite repair system and hybrid ceramic or composite blocks. The bond performance of repaired composite blocks was much more greater than than that of repaired hybrid ceramic. Thermocycling affect the bond durability of repaired hybrid ceramic blocks and composite blocks.Further investigations focusing on the effect of different surface treatments to yield results that lead to concrete clinical recommendations are needed to evaluate the long term durability of new CAD/CAM materials.

Diagnostic Wax and Mock-up Technic Use and Property as a Diagnostic Method for the Performing Sector Anterior Composite Resins

En la actualidad las consultas dentales por alteraciones estéticas han ido en aumento, considerándose que los dientes anteriores son los que principalmente se ven cuando una persona habla o sonríe, se deja de manifiesto que éstos son actores esenciales dentro de la estética de un paciente. Sin embargo también debemos preocuparnos de la conservación y/o devolución de guías de desoclusión para así lograr una oclusión mutuamente protegida. Con los avances tecnológicos que ha habido en adhesión esto perfectamente se puede lograr mediante resinas compuestas con una técnica mínimamente invasiva y a un menor costo. Se presenta a consultar una paciente que acaba de terminar su tratamiento de ortodoncia, y a la cual el especialista le indicó que debía tratarse múltiples caries en los molares, pero al realizar la revisión inicial nos encontramos con un grave problema estético en los dientes anterosuperiores, se le ofreció a la paciente tratar dicho problema mediante una técnica de encerado diagnóstico, Mock-up y posteriormente la realización de restauraciones mediante resinas directas. El propósito de presentar este caso clínico es mos- trar una técnica de Mock-up modificado que resulta útil tanto como herramienta diagnóstica como para distintos pasos dentro del mismo tratamiento restaurador.

Direct resin composite restoration of maxillary central incisors using a 3D-printed template: two clinical cases

BackgroundThree-dimensional (3D) printing technology is used widely in dentistry for applications including implant surgery, oral and maxillofacial surgery, orthognathic surgery, endodontics and prosthodontics. Using a 3D-printed template makes performing the repair procedure faster and more convenient. The aesthetic restoration of anterior teeth can recover facial beauty, enhance speaking and chewing functions and improve the quality of life of the patient.Case presentationThis article describes two kinds of clinical cases including fractured teeth and dental caries. In both, a 3D-printed template was used for direct resin composite restoration of maxillary central incisors. A 3D-printed template was built using the following 3-step process: data acquisition was conducted via intra-oral scanning, virtual modeling was performed using an imaging process, and manufacturing was performed using a 3D printer. Aesthetically restoring the maxillary incisors with the assistance of the 3D-printed template achieved the anticipated results, and the patients were very satisfied with the effect.ConclusionsThe direct resin composite restoration of maxillary central incisors using a 3D-printed template represents a rapid, convenient, aesthetic and functional option for treating maxillary central incisors. A 3D-printed template is therefore an acceptable and reliable alternative to traditional direct composite restoration of maxillary central incisors including fractured teeth and dental caries.

Interaction between photoactivators and adhesive systems used as modeling liquid on the degree of conversion of a composite for bleached teeth

Objective: This study analyzed the effect of two light emitting diodes (LEDs) on the degree of conversion (DC) of a composite resin for bleached teeth under the influence of adhesives systems used as modeling liquid. Material and methods: A total of 60 samples of IPS Empress Direct resin (Ivoclar, Vivadent) in BL-L shade were made in a single increment and polymerized for 20 seconds. The treatments were: 1) Type of adhesive used as modeling liquid (Adper Single Bond 2; the bond component of Adper Scotchbond Multi-Purpose; or no adhesive systems used as modeling liquid were used in the control group); and 2) Type of LED (Bluephase, polywave; and Coltolux, monowave). The DC, percentage of monomers converted to polymer during polymerization, was were evaluated using Fourier Transform Infrared Spectroscopy (FTIR) with 10 scans and wavenumber related to 1/? for observation of the peaks at 1608 and 1638 cm-1. Data were statistically analyzed by two-way analysis of variance (ANOVA) with Tukey's test (p&lt; 0.05). Results: There was no statistical difference between LEDs in comparison to the treatments (p&gt; 0.05). However, there was a statistically significant increase in the DC for the adhesive systems tested in comparison to the control group (p&lt; 0.05), with the highest values for Single Bond 2. Conclusion: It is concluded that the use of adhesives as modeling liquid of Empress Direct resin for bleached teeth shade increases the degree of conversion of the composite surface, and that curing with both kinds of LEDs does not interfere in this property. KeywordsComposite resins; Dentin-bonding agents; Surface properties.

Low shrinkage composite resins and occlusal matrix technique: association for direct extensive resin restoration

INTRODUCTION: Ensuring adequate occlusal contacts and anatomy shape and form is always a challenge when placing extensive direct posterior composite resin restorations. The use of a correct technique, such as, an occlusal matrix can reproduce occlusal morphology more precisely. Additionally, recently, silorane-based or bulk fill composite resin present low shrinkage and were specifically designed for restoring posterior teeth.CASE REPORT: This report presents the clinical application of a low shrinkage composite resin system with a preoperative occlusal matrix in extensive composite resin restoration of a molar with hypomineralization. Acrylic resin was applied over the waxed tooth to copy the anatomic details. Cavity was prepared and bonding system was applied. Definitive layer in the occlusal matrix was applied and stabilized in position. Once curing was complete, occlusal matrix and resin excess were removed using a surgical blade.CONCLUSION: The application of these materials with occlusal matrix can provide a simpler technical approach, saving time and improving esthetic results.

Effects of three drying methods of post space dentin bonding used in a direct resin composite core build-up method

PurposeThe purpose of this study was to evaluate drying methods for post space dentin bonding in a direct resin composite core build-up method. MethodsExperiment 1: Four root canal plastic models, having diameters of 1.0 or 1.8mm and parallel or tapered shapes, were prepared. After drying each post space using three drying methods (air drying, paper-point drying, or ethanol drying, which involves filling the space with 99.5 vol% ethanol followed by air drying), the residual liquid in the models was weighed. Experiment 2: Thirty endodontically treated single-root teeth were dried using the above-described drying methods and filled with dual-cure resin composite. The bonded specimens were sectioned into square beams of approximately 1mm2 for microtensile bond strength (μTBS) testing. Nine teeth were observed through transmission electron microscopy (TEM) and micro computed tomography (μCT). The weight of residual liquid and μTBS were analyzed using Scheffé multiple comparison. ResultsExperiment 1: The results of air drying were significantly different from those of paper-point drying (p<0.001) and ethanol drying (p<0.001), and no significant difference was observed between paper-point drying and ethanol drying. Experiment 2: The μTBS significantly decreased in the order of ethanol drying, paper-point drying, and air drying (air drying/ethanol drying: p<0.001, air drying/paper-point drying: p=0.048, ethanol drying/paper-point drying: p=0.032). TEM and μCT observation revealed a sufficient dentin/adhesive interface in the ethanol drying group. ConclusionsEthanol drying was found to be more effective for post space dentin bonding, as compared with air drying and paper-point drying.

Influence of the restorative procedure factors on stress values in premolar with MOD cavity: a finite element study.

In order to investigate the influence of cusp reduction, cavity isthmus width, and restorative material on stress values in premolar with mesio-occlusal-distal (MOD) cavity, numerical simulations were done on three-dimensional (3D) models of a maxillary second premolar designed using computerized tomography (CT) scan images. The use of four restorative materials (direct resin composite, direct resin composite with resin-modified glass-ionomer cement as the base, indirect resin composite, ceramic), three cavity preparation designs (without cusp coverage, 2-mm palatal cusp coverage, 2-mm palatal and buccal cusp coverage), and two cavity isthmus widths (1/2 and 2/3 intercuspal width) were simulated. After applying a static load of 200N on the occlusal surface of the tooth, von Mises stresses in the enamel, dentin, and restoration were calculated using finite element analysis (FEA). Stress values in the enamel were primarily influenced by cavity preparation design, while restorative material showed higher contribution in dentin. The lowest stress values were obtained in models with cusp coverage and indirect restorations. Cavity isthmus width had minimal influence on stress values in tooth structures. None of the investigated factors determined stress values in the restoration. In conclusion, the use of ceramic restoration covering both palatal and buccal cusp provided the most favourable stress distribution of premolars with MOD cavity. Graphical abstract ᅟ.

Comparison of the clinical efficacy of two different types of post systems which were restored with composite restorations.

AIMTo compare the efficacy of resin composite restorations, retained with either polyethylene or zirconia-rich glass fiber posts.METHODSSixty-two single rooted maxillary and mandibular central incisor teeth in forty-four patients (15 males and 29 females; age range 15-32 years) were restored either with an ultrahigh molecular weight polyethylene (UHMWP) fiber post (Bondable Reinforcement Ribbon, DENSE, Ribbond, Seattle, WA, United States) or a zircon-rich glass fiber post (Snowpost, Lot H 040; Carbotech, Ganges, France). Then, direct resin composite restoration (Clearfil AP-X, Kuraray) was performed for both post systems in tooth color suitable. Patients were recalled for routine inspections at 6 mo, 1, 2 and 3 years.RESULTSThe restorations were assessed during each recall evaluation according to predetermined clinical and radiographic criteria (periapical lesion; marginal leakage and integrity; color stability; surface stain and loss of retention of the post or the composite build-up material). The follow-up data showed no significant difference in these criteria between polyethylene fibre posts and zirconia-rich glass fibre posts.CONCLUSIONThe efficacy of resin composite restorations, retained with either polyethylene or zirconia-rich glass fiber posts were similar, suggesting that both types of fiber post can be used successfully to help retain resin composite restorations.