The impact of Bis-GMA free and Bis-GMA containing resin composite as posterior restoration on marginal integrity: a randomized controlled clinical trial.

BACKGROUND: There have been concerns surrounding the utilization of Bis-GMA, a type of bisphenol A (BPA) derivative, within the dental industry. The aim of this study was to compare the performance of bulk fill Bis-GMA-free resin composite class II restorations in respect of its marginal integrity in comparison to bulk fill Bis-GMA-containing resin composite class II restorations over a 12-month period in a parallel clinical trial utilizing a split-mouth, double-blind, randomized strategy. METHODS: 20 patients participated in this study. Each patient has received one pair of class II posterior restorations, Bis-GMA-free (Admira fusion x-tra), and Bis-GMA containing (x-tra fil) on each side of the mouth (split-mouth strategy), (n = 40). The restorations' marginal integrity was evaluated based on Ryge's criteria (modified USPHS) at baseline (after 1 week), as well as 1 month, 3 months, 6 months, 9 months, and after 12 months of follow-up by two calibrated examiners. The statistical analyses utilizing the Friedman and Wilcoxon tests, the significance level was adjusted to 0.05. RESULTS: Following the 12-month period, all patients attended the recall visits to evaluate the restorations. The Wilcoxon signed-rank and Friedman tests, revealed that both types of bulk fill had 100% of Alpha (A) scores at baseline and after 1 month with no significant statistical differences. After 3, 6, 9, and 12 months, both tested bulk fill restorations showed Bravo (B) score with Bis-GMA free 10% and 5% for Bis-GMA containing with no statistically significant difference (p ≤ 0.05) for clinical marginal integrity parameter in USPHS criteria. CONCLUSIONS: Bis-GMA-free resin composites demonstrated satisfactory, marginal integrity compared with Bis-GMA-containing resin composites within 12 months. TRIAL REGISTRATION: The protocol of the current study was registered at www. CLINICALTRIALS: gov , with the identification number NCT05480852 on 29/07/2022. All procedures involving human participants were performed in accordance with the ethical standards of the Research Ethics Committee of the Faculty of Dentistry, Minia University, Egypt, under the approval number 419 on 27/06/2020.

Multidisciplinary management of a tooth with severe root dilaceration and enamel hypoplasia: a case report.

Dental trauma in primary teeth can cause irreversible changes in the development of permanent tooth germs, including enamel hypoplasia, crown dilaceration, and root dilaceration. This article discusses multidisciplinary treatment of enamel hypoplasia and root dilaceration in the maxillary left central incisor of an 11-year-old girl. A 10-year follow-up is reported to demonstrate the long-term clinical outcomes. At the initial presentation, the patient's mother reported that the child had an accident at the age of 2 years, resulting in intrusive luxation of the primary maxillary left central incisor. After the accident, the patient was monitored for eruption of the permanent successor tooth, and different approaches were proposed during each period of the patient's development on the basis of the clinical diagnosis of root dilaceration and enamel hypoplasia. The crown was restored with composite resin, and the root defect was restored with resin-modified glass ionomer cement. After 10 years, the clinical outcomes highlight that the multidisciplinary approach was successful in preserving the natural tooth with good periodontal health conditions.

Survival and success of composite resin restorations in endodontically treated maxillary incisors with minimal structure loss.

The primary aim of this study was to evaluate the clinical performance of nanofilled composite resin restorations in traumatized, endodontically treated maxillary incisors with structural loss of 40% or less. The performance of the restorations was assessed in terms of longevity (survival) and esthetics (success) over a 20-month period. The secondary objective was to employ a novel digital method to quantify preoperative tooth structure loss. Sixty-one fractured maxillary incisors in 55 patients were included in the study. The teeth were photographed with a digital single-lens reflex camera equipped with a macro ring flash. The amount of lost tooth structure was calculated with digital photography software. The teeth were restored with a nanohybrid composite resin and self-etching adhesive system bonding agent. To assess esthetics, color change in the blue-yellow axis (Δb*) of the composite resin restoration was evaluated digitally with the Commission Internationale de l'Eclairage (CIE) L*a*b color system. The Wilcoxon signed-rank test was used to assess Δb*, and a Kaplan-Meier survival analysis was used to assess the longevity of the restorations. The study findings showed a statistically significant difference between pretreatment and posttreatment b* values (P < 0.05), but the difference was too small to be clinically perceptible to the human eye. A total of 5 restorations (9.8%) failed. The remaining restorations survived for a mean (SD) period of 18.6 (4.4) months. The log-rank test did not show any significant association between the amount of residual tooth structure and success of the restoration. The results of this study showed that use of direct composite resin restorations in endodontically treated maxillary incisors resulted in acceptable survival and success rates. Trial registration: Clinical Trial Registry of India No. CTRI/2020/01/023019.

Evaluation of shade matching of a novel supra-nano filled esthetic resin composite employing structural color using simplified simulated clinical cavities.

OBJECTIVE: To evaluate the shade matching ability of a novel supra-nano filled esthetic resin composite employing structural color technology using simplified simulated clinical cavities. Filler morphology and light transmittance characteristics were also evaluated. MATERIALS AND METHODS: One-hundred and twenty frames of resin composite were built in A1, A2, A3, and A4 shades to simulate Class I cavities (diameter = 4 mm, height = 2 mm). For each shaded frame, cavities were filled with three different types of filler containing resin composites (n = 10): supra-nano filled (SN filled) resin composite, microhybrid filled (MH filled) resin composite, and clustered-nano filled (CN filled) resin composite. Color parameters were calculated using CIELAB (△Eab ) and CIEDE2000 (△E00 ). Data were analyzed using one-way analysis of variance (ANOVA), followed by Duncan's test (α = .05). Filler morphology and light transmittance characteristics were measured to explore the role of structural color on shade matching. RESULTS: △Eab and △E00 of SN filled resin composite were significantly lower in A2, A3, and A4 shades (P < .05). CONCLUSIONS: The SN filled resin composite showed better shade matching with A2, A3, and A4 shades of resin composite frames compared to MH filled resin composite, and CN filled resin composite. CLINICAL SIGNIFICANCE: Universal-shade resin composites, which were expected to match nearly all shades, simplify the restorative procedure. Resin composite, which contained spherical supra-nano filler particles, could contribute most to its shade matching by stimulating structural color. Structural color technology may provide additional benefits for shade matching of resin composites.

Treatment of severely decayed anterior primary teeth with short-post technique (Mushroom Restorations) under general anesthesia.

AIMS: The aim of this study was to evaluation the treatment success of the short post technique (mushroom restoration) using a composite resin in severely decayed primary anterior teeth after 6, 12, and 18 months after treatment. METHODS: Eighteen children aged 3-5 years with severely decayed primary maxillary anterior teeth (60 anterior maxillary primary teeth in total) were included. Patients were treated under general anesthesia (GA). After pulpectomy, a "mushroom shape" was formed in the root canals for the purpose of retention, and the root canals were filled with zinc oxide-eugenol (ZOE), and the teeth were restored with composite resin. The status of treatment was evaluated clinically and radiographically for periapical radiolucency, pathological root resorption, marginal fracture, and loss of restoration for each treated tooth. All findings were recorded. RESULTS: As a result of the evaluation criteria, the success rates at 6, 12 and 18 months were 86%, 80%, and 71%, respectively. None of the teeth showed apical radiolucency or pathological root resorption at the end of the 18th month period. CONCLUSION: The short-post (mushroom restorations) technique is a clinically acceptable alternative method for restoration of severely decayed primary teeth. This study supports the feasibility of treatment with this technique for pediatric patients treated under GA.

Gingival tissue reaction to direct adhesive restoration: A preliminary study.

INTRODUCTION: It is debated whether composite resin marginal/submarginal direct restoration can be usefully performed without inflammatory consequences. This histological study is the first human analysis aimed to compare, in the same tooth, the gingival tissue close to composite resin restorations with gingival tissue close to hard tissue. METHODS: Eight healthy patients with almost a residual strategic tooth needing endodontic therapy, and post-and-core restoration, then indirect prosthetic restoration, were selected. Direct margin relocation with composite resin was necessary to perform endodontic treatment. The crown lengthening with a secondary flap harvested was necessary to perform prosthetic rehabilitation. Three months after marginal relocation, the secondary flap was harvested, embedded in PMMA, 4-µm sectioned, and stained to analyze the inflammation degree. RESULTS: All patients completed post-and-core reconstruction and the planned prosthetic therapy, maintaining the stringent hygienic protocol plan. The inflammation level comparison, slightly lower in gingiva close to the teeth (3.62 ± 0.38) than in gingiva close to the composite (3.75 ± 0.26), results in a p-value of 0.11 after Wilcoxon test. CONCLUSIONS: Results highlight a minimal, statistically not significant difference in the inflammation degree after margin relocation, conceivably due to patients, teeth and cases selection, together with adopted stringent methodological and supportive measures.

A Clinical Evaluation of Deproteinization and Different Cavity Designs on Resin Restoration Performance in MIH-Affected Molars: Two-Year Results.

BACKGROUND: The aim of this study was to evaluate the clinical effects of deproteinization of the hypomineralized enamel and different cavity designs on the performance of the composite resin restorations(CRRs) placed into the cavities of MIH (molar incisor hypomineralization)-affected molars. STUDY DESIGN: 95 MIH-affected permanent first molars (PFMs) and 31 caries but not MIH-affected PFMs (126 teeth in total) were included in the study. The MIH-affected molars were divided into three groups. In Group I, all hypomineralized tissue was removed until healthy enamel was reached. In Group II, carious and cheesy hypomineralized tissue was removed until a reasonable resistance was detected in the hypomineralized tissue. In Group III, cavities designed as Group II, differently from this group deproteinization of the left hypomineralized tissue was performed prior to the placement of CRRs. Group IV served as the control group consisting of unaffected carious PFMs. Restorations were evaluated according to modified USPHS criteria for 24 months. RESULTS: The retention rates were 93.7% for Group I, 80.7% for Group II, 93.5% for Group III and 100% for Group IV. The success rate for the restorations in Group II proved significantly lower (p<0.05) than that of the other three groups. No significant difference in success rates was observed between Group I, Group III and Group IV (p>0.05) at the end of 24 months. CONCLUSIONS: Failure of the restorations was predominant in the group that the hypomineralized tissue was left surrounding the cavities. Deproteinization of the hypomineralized enamel was found to enhance the retention rates of CRRs.

Intrusion of supraerupted maxillary molar using a high interim restoration on the defective opposing tooth: a clinical report.

Wear, extraction, or fracture of all or part of a mandibular first molar can lead to the supraeruption of the opposing maxillary molar, resulting in occlusal interference and lack of restoration space. This report describes a method to gain sufficient vertical space for permanent restoration. A direct composite resin restoration was placed on the occlusal surface of a lower molar, intentionally making the interim restoration high and intruding the maxillary molar. After 6 weeks, the extruded tooth returned to the desired position, and functional occlusion was restored, enabling a ceramic restoration on the mandibular molar. No marked adverse sensory reaction was reported in this therapeutic process, and no deleterious signs were detected in the teeth, periodontium, or temporomandibular joints. The simple treatment type was effective, noninvasive, and time saving, while also preserving maximum tooth structures.

Effects of stamp material and restoration depth on the accuracy of direct composite resin restorations using stamp technique.

OBJECTIVES: To evaluate the effects of different stamp materials and restoration depths on the accuracy of direct composite resin restorations using stamp technique. METHODS: Eighty standard resin teeth were divided into four groups based on different stamp materials: flowable composite resin (FR), vinyl polydimethyl siloxane (VPS) for bite registration (VB), VPS for impression (VI) and transparent VPS (TV). Each material group was further divided into two subgroups based on restoration depth (1 and 2 mm; n = 10). Standardized Class I cavities were prepared and restored with the corresponding stamps. Pre- and post-treatment scans of each tooth were fitted using Geomagic Control X software, generating deviation distribution maps of the occlusal surface. The accuracy indicators, including mean height variation (MHV), root mean square (RMS), and proportions of height variation with different ranges (PHVrange), were recorded to evaluate the accuracy of restorations. Analysis of variance (ANOVA) were used for statistical analysis (α=0.05). RESULTS: The type of stamp material significantly affected all accuracy indicators, while restoration depth did not show a significant effect on any of the indicators. MHV values ranged from 29.70 ± 5.88 µm to 63.52 ± 9.58 µm, and RMS values ranged from 62.78 ± 8.76 µm to 101.79 ± 13.17 µm, displaying a trend of FR0.2mm values (0.70 ± 0.50 % for 1 mm, 0.94 ± 0.47 % for 2 mm). In contrast, the TV groups exhibited the lowest PHV<0.05mm values (59.69 ± 10.23 % for 1 mm, 59.67 ± 5.70 % for 2 mm), while the VI groups showed the highest PHV>0.2mm values (7.34 ± 1.58 % for 1 mm, 8.20 ± 3.16 % for 2 mm). CONCLUSIONS: The accuracy of direct composite resin restorations using stamp made of flowable composite resin was higher than that of all tested VPS materials, thereby reducing the need for occlusal adjustment and improving clinical efficiency. Besides, restoration depth had no significant impact on the accuracy of stamp technique, regardless of the stamp material used. CLINICAL SIGNIFICANCE: The accuracy of direct composite resin restorations using stamp technique with different stamp materials varies. The flowable composite resin stamp exhibits higher accuracy compared with VPS stamps, reducing the need for occlusal adjustments.

Evaluation of plasma treatment effects on improving adhesive-dentin bonding by using the same tooth controls and varying cross-sectional surface areas.

The objective of this study was to evaluate and verify the effectiveness of plasma treatment for improving adhesive-dentin interfacial bonding by performing microtensile bond-strength (µTBS) testing using the same-tooth controls and varying cross-sectional surface areas. Extracted unerupted human third molars were used after removal of the crowns to expose the dentin surface. One half of each dentin surface was treated with a non-thermal argon plasma brush, whilst the other was shielded with glass slide and used as an untreated control. Adper Single Bond Plus adhesive and Filtek Z250 dental composite were then applied as directed. The teeth thus prepared were further cut into micro-bar specimens, with cross-sectional sizes of 1 × 1 mm², 1 × 2 mm², and 1 × 3 mm², for µTBS testing. The test results showed that plasma-treated specimens gave substantially stronger adhesive-dentin bonding than their corresponding same-tooth controls. Compared with their untreated controls, plasma treatment gave statistically significant higher bonding strength for specimens with a cross-sectional area of 1 × 1 mm² and 1 × 2 mm², with mean increases of 30.8% and 45.1%, respectively. Interface examination using optical and electron microscopy verified that plasma treatment improved the quality of the adhesive-dentin interface by reducing defects/voids and increasing the resin tag length in dentin tubules.

Bond strength of conventional versus modified methods for Class IV restorations in primary incisors: An in vitro study.

Background. Aesthetic restorations of severely decayed anterior primary teeth are challenging due to the small size of the teeth and the large pulp chambers. Therefore, this study evaluated and compared the tensile and shear bond strengths of conventional versus modified methods (slot technique) of Cl IV restorations in primary incisors. Methods. A total of 120 extracted intact maxillary primary central and lateral incisors were divided into two groups. In group A, conventional Cl IV cavities were prepared. In group B, after conventional cavity preparation, four and three incisal slots were prepared on the incisal edges of the central and lateral incisors, respectively. All the teeth were restored using composite resin, and then the tensile and shear bond strengths were evaluated. Results. A statistically significant increase in the tensile bond strength of restorations was recorded in the modified technique compared to the conventional method (P=0.001). Although an increase in the shear bond strengths was found in the modified method, the value did not reach a statistically significant level (P=0.158). The most frequent fracture type was adhesive in the conventional group and cohesive in the modified group, considering the tensile and shear bond strength tests. In both groups, the highest average tensile bond strength was recorded in teeth with the cohesive fracture in dentin, and the lowest average was seen in the adhesive type. Conclusions. Incisal slots could increase the tensile bond strengths of Cl IV composite resin restorations in primary teeth.

Treatments Performed on First Permanent Molars in a Sample of Lebanese Children: A Five-Year Retrospective Analysis.

Background: Dental caries remains one of the most prevalent worldwide chronic diseases and an expensive burden to healthcare services despite significant preventative measures Objective: Dental caries is a multifactorial chronic disease that occurs in early childhood and persists until adulthood. The first permanent molars (FPMs) are the earliest permanent molars to erupt what makes them vulnerable to caries among children and adolescents. Objective: The aim of this study is to determine the prevalence of different types of treatments performed on FPMs in 7-10-year-old Lebanese patients. Methods: In this retrospective study, a convenience sample obtained from the dental electronic health record system of 753 patients, aged between 7 and 10 years old who attended the department of Pediatric Dentistry at the Faculty of Dental Medicine-Lebanese University, between 2015 and 2019 was assessed. Preventive procedures (fissure sealants and preventive resin restorations) as well as therapeutic ones (apexogenesis, composite restoration, extraction, pulp capping, radicular treatment, pulpotomy, stainless steel crown, surgery and emergency) were investigated. Data collected was statistically analyzed using SPSS version 25.0 (Armonk, NY: IBM Corp). Results: The 753 patients were divided into 364 girls (48.3%) and 389 boys (51.7%). These patients underwent a total of 2145 procedures. Procedures were equally divided between therapeutic procedures and preventive ones (51.6% versus 48.4%, respectively). The most commonly performed procedure was composite restoration (41.9%), followed by fissure sealant (34.5%) and preventive resin restorations (14%). Treatments corresponded to a similar sex distribution with slightly higher male patients (53.6%). No statistical association was found between sex and procedure type (p=0.7). Conclusion: In the present study, therapeutic treatments prevalence is relatively high. Thus, educating the parents and teachers on the importance of FPMs would reflect in increased preventive treatments at the expense of decreased therapeutic ones.

Effective Protocol for Daily High-quality Direct Posterior Composite Restorations. The Interdental Anatomy of the Class-2 Composite Restoration.

The importance of the interdental anatomy of a class-2 direct composite restoration is one of the most underestimated topics in direct posterior composite restorations. The proximal emergence profile of the restoration and the contact area should be designed to maximize arch continuity and to minimize food impaction. Other restorative criteria that must be fulfilled are marginal adaptation compatible with the dental and periodontal integrity, and geometry of the marginal ridge compatible with the mechanical integrity of the restoration under load. Shortcomings will result in masticatory discomfort, caries, periodontal problems and undesired movement of teeth. In vitro and in vivo studies showed that the use a contoured sectional metal matrix band with a separation clamp results in the tightest contact point. However, this matrix system also has shortcomings and does not give the expected result in all class-2 cavities. The variation in depth, width of the box, distance between the cervical cavity margin and the adjacent tooth requires customization of the interproximal space. In order to realize this, sectional matrix bands with several profiles of curvature, variation of wedges and separation clamps, and the use of teflon tape are required. In addition, dentists should follow a protocol allowing them to build a proximal composite surface that fulfills the required restorative criteria. Pre-wedging, space evaluation, interproximal clearance, correct selection, positioning and stabilization of the matrix band are important steps in this protocol.

Training and experience effect on light-curing efficiency by dental practitioners.

BACKGROUND: Light-curing is a crucial step during the application of composite resin restorations. Composite's success depends on delivering enough light energy to the resin to achieve adequate polymerization. However, dentists are not recognizing the importance of proper light-curing technique. OBJECTIVES: To measure light energy delivered to simulated restorations by preclinical dental students and dentists in internship year. To evaluate the effect of experience and training on the clinician's ability to light-cure composite restorations. METHODS: A group of 50 preclinical dental students and a group of 50 internship dentists light-cured for 10 seconds, a simulated class III and class I restorations positioned in a patient simulator (MARC-Patient Simulator [BlueLight Analytics Inc., Canada]) that measured the irradiance and energy delivered by the curing light. Then participants received individualized training on optimizing their light-curing technique. They were retested after the training. Statistical analysis was done with two-way ANOVA and Tukey's test. RESULTS: Participants delivered an average of 60% more energy after the instructions, which is a significant improvement (P < 0.05). The number of participants that failed to deliver the minimum amount of energy (6 J/cm²) decreased significantly from 37.5% to 2.5%. There was a significant difference in the amount of energy delivered by the Preclinical and Internship groups (P < 0.05). CONCLUSION: Initially, many participants were not using the curing light properly. Light-curing technique improved with training and using a patient simulator. Experience can enhance the operator's ability to light-cure composite restorations. However, a training session can improve light-curing performance more than years of experience.

Management of a Patient with Hypomineralized Teeth from the Mixed to Permanent Dentition Stage - A Case Report with 6-year Follow-up.

PURPOSE: This case report presents the management of molar incisor hypomineralization (MIH) from the mixed to the permanent dentition stage. Shortly after eruption of hypomineralized teeth, masticatory forces frequently cause rapid enamel breakdown. The MIH Treatment Need Index (MIH-TNI) provides guidelines for the treatment of MIH in relation to how severely the teeth are affected. Clinical considerations: An 11-year-old patient with permanent teeth affected by MIH was referred to us by his orthodontist for conservative dental treatment before planned orthodontic treatment. The restorative treatment varied according to the degree of severity of the affected teeth and included indirect composite resin restorations on teeth #17 (MIH-TNI 4c), #35 (MIH-TNI 4c) and #37 (MIH-TNI 4b), direct composite resin fillings on teeth #26 (MIH-TNI 2b), #27 (MIH-TNI 2a) and #16 (MIH-TNI 4c) and fissure sealants on teeth #16, 15, 14, 24, 25, 34, 36, 44, 45, 46 and 47. Orthodontic treatment was already started during the restorative phase with a bite-jumping appliance. With the conclusion of the second phase of mixed dentition at age 12, the orthodontist was able to start fixed orthodontic treatment of the maxillary and mandibular arches with all of the child's permanent teeth adequately restored. Orthodontic treatment was completed at age 14. At present, 6 years after initiation of dental treatment, all teeth are still free of decay. CONCLUSION: A carefully supervised recall program with early comprehensive care at frequent intervals and adequate, defect-driven restorations depending on how severely the teeth are affected are the basis for a favorable long-term prognosis in patients with MIH.

Human neutrophils compromise the restoration-tooth interface.

Neutrophils, cells of the innate immune system, enter the mouth and release factors that are hypothesized to contribute to the degradation of tooth dentin, methacrylate resin composites, and adhesives at the restoration-tooth-dentin interface. The objectives were to characterize neutrophils' degradation towards resin composite, self-etch (SE) and total-etch (TE) adhesives, SE and TE resin-dentin interfaces and to identify proteins that could contribute to the degradation process. Neutrophils' degradation of cured resin composite, and SE and TE adhesives, was quantified by measuring the specific resin degradation by-product, bishydroxy-propoxy-phenyl-propane (bisHPPP), released after 30 days incubation of the materials with the cells. Neutrophils' degradative effect on resin-dentin interfaces was examined by recording the interfacial fracture toughness (FT), and surface analysis of the fracture mode following incubation of SE and TE miniature short-rod (mini-SR) specimens with the cells. Neutrophils increased degradation of polymerized resin composite, and TE adhesive, but not SE adhesive over 30 days (p < 0.05). Incubation of SE and TE resin-dentin interfaces with neutrophils led to a reduction in FT over time (p < 0.05). The effect was more pronounced for TE interfaces. Neutrophils also affected the fracture mode of SE and TE resin-dentin interfaces. Several proteins that could contribute to the degradative activity of neutrophils, including Neutrophil collagenase (MMP-8), Matrix metalloproteinase- 9 (MMP-9), Cathepsin G, Neutrophil- gelatinase associated lipocalin (NGAL) and Myeloperoxidase, were isolated. The ability of neutrophils to degrade resin, tooth dentin, and reduce the bond strength of resin-dentin interfaces suggest neutrophils' potential role in primary and recurrent caries and dental restoration failure.

Volumetric polymerization shrinkage and its comparison to internal adaptation in bulk fill and conventional composites: A µCT and OCT in vitro analysis.

OBJECTIVE: To quantify the volumetric polymerization shrinkage (VPS) of different conventional and bulk fill resin composites, through micro-computed tomography (µCT), and qualitative comparison of gap formation through optical coherence tomography (OCT). METHODS: Box-shaped class I cavities were prepared in 30 third-molars and divided into 5 groups (n=6): G1- Filtek Z100 (Z100); G2- Tetric Evoceram Bulk Fill (TEC); G3- Tetric EvoFlow Bulk fill (TEF); G4- Filtek Bulk fill (FBU); and G5- Filtek Bulk fill Flowable (FBF). All groups were treated with Adper Single Bond Plus adhesive and light cured (Bluephase 20i). Each tooth was scanned three times using a µCT apparatus: after cavity preparation (empty scan); after cavity filling (uncured scan) and after light curing of the restorations (cured scan). The µCT images were imported into a three-dimensional rendering software, and volumetric polymerization shrinkage percentage was calculated (%) for each sample. In the same images, interfacial gaps in the pulpal floor were qualitatively evaluated. After µCT evaluation, the pulpal floor from each tooth was polished until a thin tooth structure was obtained and OCT images were obtained by scanning the pulpal portion. Gap formation was observed and qualitatively compared to the µCT images. RESULTS: VPS means ranged from 2.31 to 3.96% for the studied resin composites. The bulk fill materials, either high viscosity or flowable, were not statistically different from each other (p>0.05). The conventional resin composite Z100 presented statistically higher VPS than both high viscosity bulk fill materials studied (p<0.05), although it was statistically similar to the flowable bulk fill materials studied (p>0.05). Both µCT and OCT methodologies enabled gap formation visualization, and images from both technologies could be associated. Gap formation was mostly observed for G1-Z100, G4-FBU, and G5-FBF. VPS% and pulpal gap formation could not be completely associated with each other for all groups and samples. Voids were observed in most of the resin composite fillings, and most VPS were observed in the occlusal area of the samples. SIGNIFICANCE: Volumetric polymerization shrinkage was material-dependent, although bulk fill materials did not differ from each other. Both µCT and OCT enabled interfacial pulpal gap formation visualization. VPS and gap formation cannot be completely associated with one another.

Influence of restorative procedures on endodontically treated premolars: Finite element analysis of a CT-scan based three-dimensional model.

An endodontically treated tooth with mesial-occlusal-distal (MOD) cavity is often restored with composite resin. Palatal and buccal cusp reduction (MODP, MODPB), and/or fiber-reinforced composite posts (P), are used in an attempt to improve the longevity of the restoration. The aim of this study was to determine the effects of these procedures on von Mises stress values and distribution in dental tissues and restorative materials using finite element analysis. Based on CT scans of an extracted second upper premolar, six 3D endodontically treated tooth models (MOD, MODP, MODPB, MOD+P, MODP+P, MODPB+P) were created. Each model was subjected to a summary force of 150 N on the occlusal surface simulating the normal biting pattern and maximal von Mises stresses were calculated. MODP seems to reduce von Mises stress values in dental tissues and P seems to transfer some of the stresses from dental tissues to the composite filling.

Cross-infection control in clinical training: Development of a device for storing a composite resin in restorative dentistry.

This study presented a biosafety device for the hygienic storage of composite resin during restorative procedures in teaching clinics, RESTAURASAFE, and to compare the color stability, surface hardness, and degree of conversion of the composite resin made with the proposed device to those of conventionally made resins. Esthet-X HD composite was manipulated directly from the syringe, fractionated doses, dappen dish or RESTAURASAFE. Disc-shaped specimens were immersed in artificial saliva and coffee for 60 days and the color stability and the Vickers surface hardness were evaluated during 60 days. Degree of conversion was assessed after immersing specimens in saliva (baseline). The surface morphology analysis of composite resin has taken by scanning electron microscopy (SEM). The data were evaluated statistically by repeated measures ANOVA (α=.05). No difference of color stability was observed for saliva and coffee regardless of storing devices. The resin manipulated directly from the syringe presented lower hardness, and fractionated doses presented lower degree of conversion than the RESTAURASAFE. SEM analysis showed that after artificial aging in coffee for 60 days, the specimens prepared with fractionated doses of resin displayed the fewest changes in surface morphology, followed by those prepared with the RESTAURASAFE. We conclude that RESTAURASAFE allows to obtain similar color stability, higher hardness, and degree of conversion of the composite in comparison to the other storing devices.