Resin Restorations Research Articles

A digital workflow for layering composite resin restorations by using 3-dimensionally printed templates to replicate the contralateral tooth accurately and rapidly

This article described a digital workflow for layering composite resin restorations by using a digital software program and 3-dimensionally printed templates. To mimic the appearance of the natural tooth, the computer-aided design was used to copy the shape of the contralateral tooth. Three-dimensionally printed templates to replicate the contralateral tooth accurately and rapidly can help dentists build different layers of dentin and enamel composite resin, achieving layered esthetic outcomes. This workflow provides an efficient and accurate procedure, reduces chairside time, and simplifies the application of the technically sensitive composite resin layering technique.

Effect of Wet and Dry Polishing Conditions by Two Finishing and Polishing Systems on the Surface Roughness and Color Changes of Two Composite Resin Restoratives: An In Vitro Comparative Study

Purpose: The study aimed at evaluating the effect of wet and dry polishing systems on the resin composites’ surface roughness and color change. Materials and Methods: In the study, samples were prepared using nanoceramic (Ceram.x one) and nanohybrid (GrandioSO) resin composites. Two different finishing and polishing systems were used in the polishing of resin composites. Resin composite surfaces were finished and polished under wet and dry conditions. The initial surface roughness values (Ra) of the samples were measured using a profilometer, whereas the color changes were measured using a spectrophotometer. Then, the colors of the samples kept in coffee were measured on the 7th and 30th days. Surface roughness and color change values (ΔE00) were measured and statistically analyzed using the one-way analysis of variance (ANOVA) test ( P < .05). Results: Wet or dry use of polishing systems did not show a statistically significant difference between the surface roughness values of the resin composite ( P < .05). Wet and dry use of polishing systems showed similar color changes on the composite resins ( P < .05). Diamond-containing spirals on composite resins showed statistically less color change than aluminum-oxide-containing discs ( P < .05). Wet or dry use of polishing systems did not reduce the color change of the composite resins below the acceptability threshold (AT). Conclusion: Wet or dry use of polishing systems on composite resins did not affect surface roughness and color change. The use of diamond-containing polishing spirals that cause less color change can increase clinical success.

Development and Assessment of Bioactive Coatings for the Prevention of Recurrent Caries Around Resin Composite Restorations.

To develop hydrophilic resin-based surface coatings containing bioactive agents (proanthocyanidins from Vitis vinifera and calcium silicate) and assess their protective role at the dentin and enamel margins of cervical restorations against demineralization under simulated conditions of high and low caries activity. Suboptimal resin composite restorations were placed on cervical cavity preparations on buccal and lingual surfaces of thirty-two molars after a contamination protocol. Groups were divided according to the resin-based coatings (n=8): resin without bioactive (C), resin containing 2% enriched Vitis Vinifera (VVE), and resin coat containing 10% calcium silicate (CaSi). The control group did not receive a resin (NC). To simulate a hydrolyticenzymatic degradation, specimens were subjected to 2-month storage followed by incubation in esterase at 37°C for 8 days. Afterwards, recurrent caries was induced using a pH-proteolytic model on half of the specimens to simulate high caries activity, and the other half remained in simulated body fluid (SBF). Measurements of cross-section microhardness (KHN) and infiltration with rhodamine-B assessed the micropermeability (MP), the extent of demineralization (ED), and the demineralization area (DA). Data were analyzed using analysis of variance (ANOVA) and post-hoc tests (α=0.05). VVE and CaSi presented higher cross-sectional KHN values for enamel and dentin (p<0.001). The bioactive coatings resulted in lower MP, ED, and DA compared to NC (p<0.005) in enamel and dentin. CaSi coating preserved the enamel from demineralization (p=0.160). The application of bioactive coatings represents a potential strategy to protect the enamel-dentin margins of resin restorations.

NaOCl Application after Acid Etching and Retention of Cervical Restorations: A 3-Year Randomized Clinical Trial

This study evaluated the retention of composite resin restorations in noncarious cervical lesions (NCCLs) performed with or without pretreatment with 10% NaOCl solution (deproteinization). A randomized, controlled, split-mouth, double-blinded trial was carried out. Thirty patients with at least two NCCLs were included in the study. The NCCLs were randomly allocated into two treatment groups: control (acid etching with 37% phosphoric acid + placebo solution + Adper Single Bond 2/3M Oral Care + Filtek Z350/3M Oral Care) or experimental group (acid etching with 37% phosphoric acid + 10% NaOCl solution + Adper Single Bond 2 + Filtek Z350). A calibrated examiner evaluated the restorations at baseline (1 week) and recalls (6, 12, 24, and 36 months) using the FDI criteria. The primary outcome evaluated was retention of the restorations. Data were analyzed by the Kaplan-Meier method and the log-rank test (α=0.05). After 3 years, 64 restorations were evaluated in 23 patients. The annual failure rate was 9% for the control group and 17.8% for the experimental group (deproteinization technique). Considering the failures and their distribution among the characteristics of the patients and NCCLs, no statistically significant differences were observed for the control and experimental treatment groups (p=0.077) or the number of teeth in the mouth (p=0.320). Restorations in the mandible (p=0.039) and premolars (p=0.013) showed significantly lower clinical survival rates. The deproteinization pretreatment with a 10% NaOCl solution did not promote additional retention of restorations in NCCLs. (clinicaltrials. gov: NCT03086720).

Life changing dentistry with Full Mouth Rehabilitation – a case report

Tooth wear is caused by a variety of reasons, many of which are unknown. Tooth wear management is difficult and complex. For effective treatment, accurate measurement of occlusal vertical dimension (OVD), interocclusal rest space, and centric relation records are required. The analysis of facial soft tissue contours is very crucial. A clinician must remember two things before treating a case with full mouth rehabilitation; severe wear does not always cause loss of OVD and it also does not eliminate all defective occlusal interferences. A systematic method may be beneficial in achieving a predictable and desirable result. This paper describes the step-by-step treatment of a 63-year-old patient who had lost occlusal vertical dimension due to parafunctional habits. Making occlusal overlay bilateral splints in acrylic resin and provisional restorations in mandibular teeth for the healing of the intermaxillary distance was the first strategy for oral rehabilitation. The ultimate rehabilitative therapy evolved into direct composite resin restorations associated with all-ceramic crowns fortified by lithium disilicate after the patient's adaption and muscle stability to the new occlusal situation. We established that all teeth had solid connections with similar intensity in centric relation, as well as anterior guiding in line with functional jaw movement. Update Dent. Coll. j: 2022; 12(1): 40-44

Youtube as an Information Source for Practitioners on Direct Diastema Closure Procedures

Background: The aim of the study was to analyze the content and quality of clinical diastema closure videos related to the direct resin composite restoration technique available on YouTubeTM. Materials and Methods: The videos were determined using the words “diastema closure,” “teeth gap fill,” and “teeth gap close” in the YouTube™ search section. 300 videos were reviewed, and 55 of them were included in the study. Demographics of videos, interaction index, and viewing rates were evaluated. The videos were analyzed in three parameters in terms of content score (CS), technical features (TF), and global quality scale (GQS). Results: The dentist accounts took the first place (51%) in the distribution of those who uploaded the videos. The mean values of the videos from the evaluation criteria were 8.3/15p for CS, 3.1/5p for TF, and 2.7/5p for GQS. There was a statistically significant positive correlation between the viewing rates, TF, and GQS values (P &lt; 0.05). Conclusion: Operational videos of diastema closure with direct composite resin restoration treatments should be uploaded to YouTube™ after approval by experts. In addition, the TF of operational videos needs to be better. Students should be warned about videos which contain insufficient information.

Impact of different light curing modes on the cuspal deflection of maxillary premolars restored with nanohybrid resin restoration

INTRODUCTION: The influence of various light-curing modes may lead to polymerization shrinkage resulting in contraction stresses in composite resin. These stresses leads to linear movement of the cusp tips of the tooth as a result of interactions between polymerization shrinkage stress of the composite and adherence of the cavity wall of the tooth. That may lead to restoration failure. AIM: Comparative evaluation of the effect of different light-curing modes on the cuspal deflection of class II Mesio-occlusal-distal cavity restored with Nano-hybrid composite resin restorative material. METHOD: Thirty-six standardized MOD preparations were prepared on maxillary first premolars. Three groups(n=12) were divided according to different light-curing modes of Blue phase LED curing light- Group 1: soft-start curing mode; Group 2: pulse curing mode; Group 3: continuous curing mode. 1mm diameter glass beads were fixed to each cusp tip as a reference point for intercuspal distance to measure initial cuspal deflection for each group. MOD Preparations were etched and bonded with adhesive resin to provide micromechanical attachment and restored with Nano-hybrid composite restoration using the incremental technique. The cuspal deflection was then measured with the Digital micrometer gauge and the mean difference was measured for each group.

Effect of Different Cavity Dimensions and Curing Systems on Cuspal Deflection of some types of Composite Resin Restorations

The cuspal deflection of different composite resin restorations cured with different systems and restoring different cavity dimensions were investigated using a total 60 freshly extracted human maxillary premolars. These teeth were divided into three main equal groups, based upon the tested restorative materials. Group (I) used T-Econpm Plus, Group (A1) (II) used Filtek Z250 XT (A2), and Group (III) used Filtek P90 (A3). Each group was subdivided into two subgroups based upon the prepared cavity dimensions. Each subgroup was further subdivided into two groups whether cured with Halogen (C1), or LED (C2). MOD cavity with two different dimensions, each restorative material was packed according to the manufacturer's instructions and cured. Dye penetration technique was used and specimens were sectioned in mesiodistal direction and examined by stereomicroscope. Collected data was statistically analyzed. The result showed T-Econom plus had statistically significant higher microleakage value, while Filtek P90 had statistically significant lower microleakage value. There was no statistically significant difference between groups cured with Halogen and LED. It can be concluded that silorane based composite, LED curing system, and smaller cavity dimension could significantly decreased cuspal deflection.

3-Year Survival of direct composite resin restorations of permanent first molars with excessive material loss in children

Aim: The aim of this retrospective study was to determine survival rates of direct composite resin (DCR) restorations of permanent first molars (PFMs) with excessive material loss at the end of 3 years. Material and methods: Children between the ages of 7-14 whose PFMs had 3-surfaced DCR restoration were included in the study. In restorations Ionofil Molar glass ionomer cement (VOCO,Cuxhaven,Germany) as base material, Clearfil SE Bond adhesive agent and Clearfil Majesty Posterior composite resin (Kuraray Noritake Dental Inc.,Okayama,Japan.) were used. Survival rates of the restorations after 3 years were evaluated using The United States Public Health Service criteria and the presence of symptoms indicating irreversible pulp damage and the need for root canal treatment such as provoked or spontaneous pain, percussion, abscess, fistula in the related teeth were examined clinically and radiographically. Chi-square and Kruskal Wallis analyzes were used for the statistical analysis. Results: Totally 58 DCR restorations of PFMs of 34 patients who agreed to come for the control visit at the end of 3 years were examined. The survival rate of restorations was 70.69% and findings indicating irreversible pulp damage were found in 15.5% of the restorations examined. Conclusion: Survival rate of DCR restorations applied to PFMs with excessive material loss is not satisfactory after 3 years, however it is thought that DCR applications will continue in PFMs with excessive material loss thanks to the developments in adhesive systems and composite resins. Therefore, long-term randomized controlled clinical studies on this subject should be continued.

Bibliometric analysis of composite resin restorations from 2000-2020

Aim: To indentify the most effective actors(authors, countries, and journals) about composite resin restorations in the period 2000-2020. Material and Methods: An electronis research was conducted in the Scopus database by selecting the words ‘composite resin’ and ‘restoration and English language, article and review types, dentistry field. Their bibliometric data including publication title, authorship, citation count, citation dentistry, year of publication, country and institution of origin, journal of publication, study design, and keywords were extracted and analyzed. Results and Discussion: To our knowledge, this is the first bibliometric article on composite resin restorations. This study provides information about authors, institutions and countries that contribute to significant improvements in composite resin restorations. From 2000 to 2020, there were 7118 articles published from 99 countries.Articles originate primarily from the USA and Brazil. Results indicate that the USA, Brazil, Germany, Turkey, the United Kingdom, Japan, Swtizerland, Italy, Netherlands and India are the leading countries in composite resin restoration research and account for 51.8% of the total number of publications. The total number of citations are 158.404, corresponding to 22 citations per paper publication. During the time period examined, 776 hot articles and 228 classic articles on composite resin restorations were found.The journal with the most publications is ‘Operative Dentistry’. The publishing houses of the top 10 journals are from 4 countries: USA(6),Netherlands(2),Germany(1),Japan(1). The most cited article within the boundaires of this study is Ferracane’s article titled ‘Resin composite-State of the art’, which was published in Dental Materials in 2011 and received 913 citations. Conclusion: This article is the first known bibliometric analysis of composite resin restorations. Studies on composite resin restorations are increasing in parallel with the increasing demand for aesthetics. The analysis of the most influential factors of these publications will give an idea for the studies to be done.

Effect of magnification factor by Galilean loupes on working posture of dental students in simulated clinical procedures: associations between direct and observational measurements.

ObjectivesTo determine the effect of different levels of Galilean loupe magnification on working posture as measured by compliance with ergonomic posture positions, angular deviation from the neutral position of the neck, and muscle activation in the neck and upper back region during simulated clinical conditions.MethodsAn experimental laboratory study was performed in which the dependent variables were compliance with ergonomic posture requirements while performing simulated restorative procedures in Restorative Dentistry, angular deviation from the neutral position of the neck, and muscle activation in the neck and upper back. The independent variable was the level of Galilean loupe magnification, which was tested at four levels (naked eye, 2.5× magnification, 3.0× magnification, and 3.5× magnification). The cavity preparations and Class I composite resin restorations were performed on artificial first molars on a mannequin in a dental chair. The Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP) was used for the postural analysis; as was an analysis of the angular deviation from the neutral position of the neck and surface electromyography. Working posture was recorded on video over the course of the procedure. Participants were filmed from three different angles. The Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP) assessed compliance with ergonomic posture requirements. A locally produced posture assessment software analyzed angular deviation. Surface electromyography bilaterally assessed activation of the sternocleidomastoid, descending trapezius and ascending trapezius muscles. Two-factor analysis of variance (ANOVA) and either Tukey’s post-hoc test or the Games-Howell post-hoc test were performed (α = 0.05).ResultsDuring the cavity preparations and restorations, the use of Galilean loupes at all magnifications positively influenced working posture as measured by participants’ compliance with ergonomic posture positions (p < 0.01) and neck angulation (p < 0.01); the use of these loupes did not affect muscle activation in the regions evaluated (p > 0.05).ConclusionThe use of Galilean loupes had a positive effect on dental students’ working posture during the restoration procedures performed.

Evaluation of composite restorations in primary molars subjected to selective caries removal associated with antimicrobial photodynamic therapy: A randomized controlled trial.

Antimicrobial photodynamic therapy (aPDT) has been used as an adjunct treatment of deep caries lesions; however, studies on the effects of aPDT on the longevity of restorations are still limited. To evaluate the clinical performance of composite restorations in primary molars subjected to selective caries removal (SCR) associated with aPDT. A randomized clinical trial was designed. Primary molars of patients (mean age 6.15years) with deep caries lesions without signs and symptoms of pulpal involvement were selected. A total of 64 teeth were randomly divided into groups G1 (SCR, 32 teeth) and G2 (SCR+aPDT, 32 teeth) for treatment, restored with composite, and evaluated after a week (T0 ), 6months (T1 ), and 12months (T2 ) according to the criteria of FDI. Groups were compared using the Rao-Scott chi-squared test and the logistic regression analysis for complex designs to account for multiple observations per subject (alpha=0.05). From all FDI criteria evaluated, the marginal adaptation for the SCR+aPDT group was significantly better in comparison with the SCR group at T0 and T2 in the logistic regression analysis (T0: OR=0.151; 95% CI=0.03-0.068, P=.015; and T2: OR=0.201; 95% CI=0.05-0.79, P=.022). The marginal adaptation of primary molar resin restorations was positively affected by aPDT after 12months of follow-up.

ANALYZE OF THE EFFECTIVENESS AND VERSATILITY OF THE COMPOSITE RESIN STRATIFICATION TECHNIQUE FOR REHABILITATING AESTHETIC TREATMENT - CLINICAL CASE REPORT

The search for the patterns of beauty and perfection of dental shapes and dimensions has provided a greater appreciation of the appearance of individuals of all ages, because the media has overestimated aesthetics. The composite resins have mechanical properties suitable for use in all types of cavity preparations. However, there are still concerns when the materials are used in situations of high stress, which can cause fracture of the restoration as well as wear, staining, marginal infiltration, translucency and patient satisfaction. Therefore, the objective of this project is to evaluate the proservation of composite resin in complex aesthetic restorations in anterior teeth, through two clinical cases, diastema closure and reanatomization of conidial teeth performed 6 years ago through Federation Dental International indices. It is concluded that the correct execution allied to the dental anatomy domain and knowledge of the properties of the composites achieved satisfactory results that exceeded the expectations of the patients.

Effect of a fiber-reinforcing technique for direct composite restorations of structurally compromised teeth on marginal microleakage.

To evaluate if the marginal microleakage of extensive Class I composite resin restorations can be affected by applying ultra-high-molecular-weight polyethylene (UHMWPE) fibers with the wallpapering technique combined with different restorative materials and methods. A 120 human molars were selected and one extensive Class I cavity was prepared on the occlusal surface of each tooth. The specimens were divided into 12 groups (n=10) according to the type of restorative material (Filtek Z550, Beautifil II LS or Beautifil Bulk Restorative), the use or not of reinforcing fibers (ribbond) and the applied restorative technique (incremental or bulk). The specimens were subjected to thermocycling and then immersed into a 50 wt% silver nitrate solution following a dying protocol. Subsequently, the teeth were prepared for SEM observations to evaluate the extent of marginal microleakage. Three-way ANOVA revealed that the type of material, the use of ribbond fibers and the type of restorative technique significantly affected marginal microleakage (p < 0.001). Application of ribbond fibers decreased marginal microleakage to all tested restorative materials, regardless of the restorative technique, in a range of 31.2-81.4%. In the groups with no-use of ribbond fibers, among the materials there were no significant differences in microleakage when the teeth were restored with the incremental technique (p > 0.05). The use of UHMWPE fibers with wallpapering technique in Class I composite restorations may be an effective method to reduce marginal microleakage, regardless of the selected restorative technique or the material. Clinicians may be encouraged to utilize reinforcing fiber restorative techniques for direct restorations of structurally compromised teeth as a valid alternative to indirect restorations.

Mechanical characterization and adhesive properties of a dental adhesive modified with a polymer antibiotic conjugate

This study is a follow up investigation on recent work by our group demonstrating synthesis, release and strong antibacterial character of resins modified with penicillin V (PV)-based polymer-antibiotic conjugates (PACs). Here, we aimed to evaluate the mechanical, bonding, and other relevant biomedical properties of a commercial adhesive resin modified with PV-PAC. Single Bond Plus (SB+) was modified with PAC containing 1.8 wt% conjugated PV. Adhesive resins were bonded to dentin from extracted human molars and restorative resin added. Beams of cross-sectional area of 0.9 ± 0.1 mm (Kutsch and Young, 2011) (n = 20) were obtained from the molars and tested for micro-tensile bond strength (μTBS) at 24 h and 4 months. For cohesive strength, hourglass beams (10 × 2 × 1 mm; n = 10) were assessed for ultimate tensile strength (UTS), beam-shaped specimens (25x2x2 mm; n = 10) evaluated for flexural strength and modulus (FS/FM) via three-point bending, and cylindrical specimens (3 × 2 mm; n = 10) assessed for ultimate compressive strength (UCS). For surface micro-hardness (MH), cylindrical specimens (3 × 2 mm; n = 6) were assessed before and after an EtOH challenge. The degree of conversion (DC) (5 × 1 mm; n = 6) was determined based on changes in absorbance ratio between peaks at ∼1637 cm-1 and ∼1608 cm-1 before and after curing of adhesive resins using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. To monitor water uptake and diffusion kinetics over a 28-day period, specimens (5 × 1mm) were desiccated, weighed and stored in deionized water. Control and PV-PAC modified adhesive resins demonstrated similar μTBS at 24 h and 4 months; both showing decrease in values after 4 months (p = 0.001 and 0.004). No significant differences between adhesive resins were shown in UTS, FS/FM or UCS (p<0.05). MH of PV-PAC adhesive resin was significantly reduced relative to the control (p<0.001). The DC values of the adhesive resins were not significantly different. While sorption and solubility were no different between materials, the diffusion coefficient of PV-PAC modified adhesive resin was higher than the control (p<0.001). We conclude that incorporation of PV-PAC with 1.8 wt% PV into an adhesive resin does not adversely affect its mechanical, bonding, and physical properties, thus providing a promising option for materials with long-term antibacterial character and on-demand release.

The aesthetic management of a midline diastema with direct composite using digital smile design, putty index and button shade technique: A case report

Background: A diastema is the distance or space between two or more adjacent teeth. This abnormality can interfere with the aesthetics of a patient, and 97% of diastemas occur in the maxilla. Various treatments can be performed for diastema closure in patients, one of which is composite resin restoration. Purpose: To explain the aesthetic procedure for diastema closure. Case: A 20-year-old female patient presented with complaints of the distance between her anterior teeth (Class I Angle occlusion with normal overjet and overbite). The labial frenum associated with the diastema was normal in size and position. The patient was not amenable to invasive procedures. Case Management: Management of midline diastema closure using the direct composite technique with DSD, the putty index method and button shade technique. Conclusion: The closure of a midline diastema with direct composite using DSD, the putty index method and button shade technique provides aesthetic results with less cost and time due to the absence of laboratory procedures.

Promoting mineralization at biological interfaces Ex vivo with novel amelotin-based bio-nano complexes

Interfacial failure at the resin-dentin interface is a significant disadvantage of resin-based dental restoration. In this study, we created bio-inspired bio-nano complexes using the enamel protein amelotin (AMTN) or AMTN with an engineered collagen-binding site (AMTN-Col) to coat hydroxyapatite nanoparticles (HANP). The resulting nano-bio complexes, AMTN-HANP and AMTN-Col–HANP, were evaluated for their ability to promote collagen mineralization. Our study comprises three separate phases.In phase I, developing a method for functionalizing HANP with AMTN/AMTN-Col was explored. HANP were synthesized and characterized using TEM, SAED-TEM, XRD and ATR-FTIR. The nanoparticles were functionalized with AMTN or AMTN-Col. The successful coating of the nanoparticles with the proteins was confirmed using a TEM image of immunogold-labelled samples.In phase II of the study, the mineralization potential of the synthesized bio-nano complexes was studied using model systems consisting of simulated body fluid (SBF), polymerized collagen gels, and dentin disks prepared from human extracted molars. Mineral formation in SBF was recorded with a light scattering assay using a microplate reader on 8 replicates of each sample per study time point. Statistical analysis was performed using one-way ANOVA and the Tukey test. Significance was assigned at P ​< ​0.01. The extent of mineral formation on collagen gel and remineralization of demineralized dentin was studied with SEM. Accelerated mineral formation collagen mineralization of bio-nano complexes treated samples were observed in all model systems.In phase III of the study, the clinical utilization of AMTN/AMTN-Col coated HANP in bio-integration and enhancing the bond strength of a resin-based dental restoration and the dentin interface was investigated. The bio-nano complexes were applied as a pretreatment on dentin disks prepared from human extracted molars prior to the composite resin restoration. The micro-shear bond strength test was done on 8 samples per treatment group (a total of 32 samples). Statistical analysis on shear bond strength was performed using one-way ANOVA and the Tukey test. Significance was assigned at P ​< ​0.01. Shear bond strength values indicated that pretreatment of dentin with the bio-nano complexes before adhesive application significantly improved shear bond strength.ConclusionWe have shown that AMTN based bio-nano complexes promote mineral formation on collagenous interfaces. Our findings can be the basis of new bio-inspired, bio-nano materials that may improve dental restoration longevity by enhancing the stability and integrity of the dentin-composite resin interface.

Microleakage assessment using 7th generation bonding agent with micro-hybrid composite restoration immersed in a carbonated drink – an in vitro study

Introduction: Restored teeth in the course of chewing or when exposed to thermal stimuli may lead to sensitivity. One of the significant reasons for sensitivity is microleakage. The repercussion of unaddressed microleakage leading to secondary caries and further on. The purpose of this study was to compare the microleakage of amongst different types of restorative materials which were silver amalgam and micro-hybrid composite resin with 7th generation bonding agent. And also to examine the effect of carbonated drink on microleakage. Materials and method: Forty extracted premolars were used for the study. Class V cavities were prepared on the buccal surfaces of the teeth, 1mm above the cementoenamel junction cervico-occlusal. Twenty cavities were restored with silver amalgam, and the remaining with composite resin. Group I and Group II both comprised of 10 teeth with silver amalgam restoration and ten teeth with composite resin restoration were immersed in the carbonated drink and water respectively for 15 minutes for ten days. The teeth were later immersed in methylene blue, sectioned and evaluated under a microscope. Statistical analyses used were Fisher's exact test. Result: Silver amalgam showed highest microleakage tendency in the carbonated drink, (P &gt; 0.05). In water, silver amalgam had the least tendency for microleakage. However, composite resin did not statistically significant microleakage in both carbonated drink and water. Conclusion: The silver amalgam restorations showed microleakage in both carbonated drink and water. The microleakage was significantly higher in the carbonated beverage. On the other hand, composite resin restoration showed microleakage neither in carbonated drink nor water.

3D-printed resins for provisional dental restorations: Comparison of mechanical and biological properties.

To characterize the mechanical and biological properties of three commercially available resins, which are currently used for provisional restorations and to compare them to an experimental resin intended for definitive fixed dental prostheses. Three commercially available resins: Crowntec (CT, Saremco), Temporary C&B (FL, Formlabs), C&B MFH (ND, Nextdent), and the experimental resin: Permanent Bridge (PB, Saremco) were printed and subjected to biaxial flexural strength test, finite element analysis, Weibull analysis, scanning electron microscopy, cell proliferation, immunohistochemistry and cytotoxicity assays. Samples from CT, PB, and ND were provided directly from the manufacturers ensuring ideal workflow. FL was printed using the workflow as recommended by the manufacturer, using a Formlabs 2 printer and their post-processing units Form Wash and Form Cure. From the tested resins, PB yielded the best overall results in terms of mechanical properties. Cell proliferation and cytotoxicity did not show any significant differences among materials. PB showed higher values for probability of survival predictions (35%) when subjected to 250 MPa loads, whereas the other materials did not reach 10%. Despite mechanical differences between the evaluated materials, the outcomes suggest that 3D printed provisional resins may be used in clinical settings, following the manufacturers indications. New materials intended for long-term use, such as the PB resin, yielded higher mechanical properties compared to the other materials. Alternative printing and post-processing methods have not yet been evaluated and should be avoided until further literature is available. 3D printed resins for provisional restorations have become popular with the emergence of new technologies. In this study, we evaluated three different commercially available resins for provisional restorations and one new experimental resin. The results from this study indicate that commercially available resins could be used in clinical settings under certain conditions and limited periods of time. Following the manufacturers protocols is of paramount importance to not compromise these properties.

Sealants for preventing dental caries in primary teeth.

Sealants for preventing dental caries in primary teeth.