Longevity of composite restorations is definitely not only about materials

Evaluating mechanical and surface properties of zirconia-containing composites: 3D printing, subtractive, and layering techniques

This study assessed the monotonic and fatigue flexural strength (FS), elastic modulus (E), and surface characteristics of a 3D printed zirconia-containing resin composite compared to subtractive and conventional layering methods. Specimens, including discs (n = 15; Ø = 15 mm × 1.2 mm) and bars (n = 15; 14 × 4 × 1.2 mm), were prepared and categorized into three groups: 3D printing (3D printing - PriZma 3D Bio Crown, Makertech), Subtractive (Lava Ultimate blocks, 3M), and Layering (Filtek Z350 XT, 3M). Monotonic tests were performed on the discs using a piston-on-three-balls setup, while fatigue tests employed similar parameters with a frequency of 10 Hz, initial stress at 20 MPa, and stress increments every 5000 cycles. The E was determined through three-point-bending test using bars. Surface roughness, fractographic, and topographic analyses were conducted. Statistical analyses included One-way ANOVA for monotonic FS and roughness, Kruskal-Wallis for E, and Kaplan-Meier with post-hoc Mantel-Cox and Weibull analysis for fatigue strength. Results revealed higher monotonic strength in the Subtractive group compared to 3D printing (p = 0.02) and Layering (p = 0.04), while 3D Printing and Layering exhibited similarities (p = 0.88). Fatigue data indicated significant differences across all groups (3D Printing < Layering < Subtractive; p = 0.00 and p = 0.04, respectively). Mechanical reliability was comparable across groups. 3D printing and Subtractive demonstrated similar E, both surpassing Layering. Moreover, 3D printing exhibited higher surface roughness than Subtractive and Layering (p < 0.05). Fractographic analysis indicated that fractures initiated at surface defects located in the area subjected to tensile stress concentration. A porous surface was observed in the 3D Printing group and a more compact surface in Subtractive and Layering methods. This study distinguishes the unique properties of 3D printed resin when compared to conventional layering and subtractive methods for resin-based materials. 3D printed shows comparable monotonic strength to layering but lags behind in fatigue strength, with subtractive resin demonstrating superior performance. Both 3D printed and subtractive exhibit similar elastic moduli, surpassing layering. However, 3D printed resin displays higher surface roughness compared to subtractive and layering methods. The study suggests a need for improvement in the mechanical performance of 3D printed material.

Alternative Direct Restorative Materials for Dental Amalgam: A Concise Review Based on an FDI Policy Statement

Dental restorative procedures remain a cornerstone of dental practice, and for many decades, dental amalgam was the most frequently employed material. However, its use is declining, mainly driven by its poor aesthetics and by the development of tooth-coloured adhesive materials. Furthermore, the Minamata Convention agreed on a phase-down on the use of dental amalgam. This concise review is based on a FDI Policy Statement which provides guidance on the selection of direct restorative materials as alternatives to amalgam. The Policy Statement was informed by current literature, identified mainly from PubMed and the internet. Ultimately, dental, oral, and patient factors should be considered when choosing the best material for each individual case. Dental factors include the dentition, tooth type, and cavity class and extension; oral aspects comprise caries risk profiles and related risk factors; and patient-related aspects include systemic risks/medical conditions such as allergies towards certain materials as well as compliance. Special protective measures (eg, a no-touch technique, blue light protection) are required when handling resin-based materials, and copious water spray is recommended when adjusting or removing restorative materials. Cost and reimbursement policies may need to be considered when amalgam alternatives are used, and the material recommendation requires the informed consent of the patient. There is no single material which can replace amalgam in all applications; different materials are needed for different situations. The policy statement recommends using a patient-centred rather than purely a material-centred approach. Further research is needed to improve overall material properties, the clinical performance, the impact on the environment, and cost-effectiveness of all alternative materials.

Clinical performance of posterior restorations using a universal adhesive over moist and dry dentin: A 36-month double-blind split-mouth randomized clinical trial

OBJECTIVES

To evaluate the influence of dentin moisture on the clinical behavior of a universal adhesive on posterior teeth after 36 months of follow-up.

METHODS

Forty-five patients participated in this study. Following a split-mouth design, three operators placed 90 Class I/Class II restorations over moist dentin (MD) or dry (DD) (n = 45) with resin composite (Filtek Bulk Fill) and a universal adhesive used in the etch-and-rinse mode (Single Bond Universal). Each restoration was evaluated according to the FDI and USPHS criteria (postoperative sensitivity, fracture and retention, marginal staining, marginal adaptation, and recurrence of caries) at baseline and after 6-, 12-, and 36 months. For statistical analysis, Kruskal Wallis analysis of variance rank (α = 0.05) and Kaplan-Meier survival analysis were used.

RESULTS

No significant difference between groups was observed in each FDI criterion after 36 months of clinical evaluation (p > 0.05). The retention rates (confidence interval 95 %) were 97.37 % (86.5 - 99.5) for both MD and DD without significant difference between them (p > 0.05). Eight restorations (MD = 4; DD = 4) showed minimal marginal staining defects (p > 0.05). Two restorations were lost (MD = 1; DD = 1). Fifteen restorations (MD = 8; DD = 7) presented minor marginal discrepancies according to the FDI criteria (p > 0.05).

CONCLUSION

The clinical performance of the universal adhesive when applied in etch-and-rinse mode was not influenced by dentin moisture in posterior bulk-fill composite restorations.

CLINICAL SIGNIFICANCE

The level of dentin moisture appears not to influence the clinical efficacy of a universal adhesive when applied using the etch-and-rinse technique in posterior composite resin restorations.

Advances in clinical diagnosis and management of amelogenesis imperfecta in children and adolescents

OBJECTIVE

To summarize studies published between 2017 and 2023 examining the clinical diagnosis and restorative management of amelogenesis imperfecta (AI) in children and adolescents.

DATA

The review incorporated publications on clinical diagnosis, patient-reported outcomes, clinical trials, cohort studies, and case reports that included individuals below 19 years of age with non-syndromic AI.

SOURCES

A literature search was conducted across electronic databases, PubMed, Web of Science, and CINAHL, including papers published between 2017 and 2023. The search yielded 335 unique results, of which 38 were eligible for inclusion.

RESULTS

New evidence on the genetic background of AI makes it now advisable to recommend genetic testing to supplement a clinical AI diagnosis. The discussions of the dental profession and the public on social media do not always incorporate recent scientific evidence. Interview studies are finding that the impact of AI on quality of life is more severe than previously appreciated. New evidence suggests that single-tooth ceramic crowns should be the first choice of treatment. Due to incomplete reporting, case reports have been of limited value.

CONCLUSION

In young patients with AI symptoms of pain and hypersensitivity decreased, and aesthetics were improved following all types of restorative therapy. Resin composite restorations were mainly performed in cases with hypoplastic AI and mild symptoms. Single tooth ceramic crown restorations have a high success rate in all types of AI and can be used in young individuals with AI.

CLINICAL SIGNIFICANCE

Prosthetic rehabilitation in adolescents with severe AI is cost effective, improves esthetics, reduces tooth sensitivity, and improves oral health-related quality of life.

5-year Clinical Performance of Ceramic Onlay and Overlay Restorations Luted with Light-cured Composite Resin

OBJECTIVES

This prospective clinical trial evaluated the clinical performance of ceramic partial coverage indirect adhesive restorations (PCIARs) in posterior teeth luted with a light-cured composite resin.

METHODS

From April 2016 to January 2017, a total of 60 patients (27 males, 33 females; mean age: 42.2±10.86 years old) received 83 glass-ceramic PCIARs (26 onlay, 57 overlay) made of IPS Emax CAD (Ivoclar Vivadent). All restorations were luted with a light-cured composite resin (Filtek Z250, 3M ESPE) by two operators. Two independent calibrated examiners blinded to the operators performing the treatment evaluated the restorations at baseline, 1-year, and 5-year following FDI World Dental Federation criteria including esthetic, functional, and biological properties. Data were analyzed with the Friedman test and the Wilcoxon sign test (p<0.05).

RESULTS

None of the restorations failed due to fracture or retention loss. One restoration was clinically unsatisfactory because of secondary caries. Marginal staining (p:0.000), marginal adaptation (p:0.018) showed significant differences between 1-year and 5-year recall.

CONCLUSIONS

The PCIARs demonstrated excellent clinical performance at 1-year period. The degradation parameters appeared as minor staining and minor irregularities after 5-year, without any affect on the clinical performance.

CLINICAL SIGNIFICANCE

Our findings provide evidence that the clinical performance of PCIARs luted with a light-cured composite resin was clinically acceptable after a five-year evaluation period. Due to secondary caries, only one restoration was considered clinically unsatisfactory.

Assessing one-shade composite resin color stability in response to everyday drinks

OBJECTIVE

The aim of our study was to measure the color changes in one-shade composite resins when exposed to common drinks, such as tea, cola and coffee.

MATERIALS/METHODS

In our study, Omnichroma, Vitrra APS Unique, GC A'chord and Charisma Diamond One composite resins were used. Composite resins were placed in stainless steel molds with depths of 2 mm and diameters of 5 mm. Ten specimens were immersed in tea, 10 specimens were immersed in coffee, 10 specimens were immersed in cola and 10 specimens were immersed in distilled water in an incubator at 37 °C for 14 days. Color measurements were performed at the beginning of the study and after 24 h and 14 days. Color values ​​were measured using a CIE L*a*b* system with a spectrophotometer device. Color and translucency changes were calculated and data analyzed using one-way ANOVA, two-way ANOVA, and post-hoc Tukey test (p < 0.05).

RESULTS

The greatest color changes occurred in the tea and coffee groups; the smallest color change occurred in the control group. After 14 days, the greatest color change was observed in the Charisma + Coffee group; the smallest color change was observed in the Omnichroma + Water group. The transparency and contrast ratios changed in all groups, and the smallest change occurred in the Omnichroma control group.

CONCLUSION

Significant differences were found in the composite color changes after immersion in beverages. The color variations significantly differed depending on the beverage in which the specimens were immersed. The initial contrast ratio was markedly different from the examined materials.

CLINICAL SIGNIFICANCE

The study emphasizes the significance of common beverages on the color stability of one-shade composite resins, underlining the need of appropriate material selection for long-term aesthetic effects in one-shade composite resin restorations.

Effect of dentin conditioners on dentin bond strength: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Although composite resin restorations have been widely used for dental restorations, the durability of the bond affects the rate of restoration failure. However, how multiple strategies for enhancing the resin-dentin bond affect durability is unclear.

PURPOSE

The purpose of this systematic review and meta-analysis was to evaluate the impact of dentin conditioners on resin-dentin bond strength with different pretreatments before the application of adhesives.

MATERIAL AND METHODS

The PubMed, Web of Science, EMBASE, and Cochrane Library databases were searched from 2013 to July 2023 for in vitro studies that evaluated the impact of dentin conditioners on resin-dentin bond strength. The meta-analysis was conducted using a random-effects model with pooled effect as standardized mean differences (α=.05).

RESULTS

A total of 23 studies met the inclusion criteria for qualitative analysis, of which 15 were used for quantitative analysis. The results demonstrated that, under dry bonding conditions, selective extrafibrillar demineralization dentin conditioners significantly enhanced the immediate bond strength (P<.001). The long-term bond strength was limited by the sample size of the subgroup, but a significant effect was found after using selective extrafibrillar demineralization dentin conditioners (P<.001). However, metal salt-based dentin conditioners improved the immediate bond strength only under wet bonding conditions (P=.010). Notably, acid-based dentin conditioners significantly improved the long-term bond strength under both dry and wet bonding conditions (P<.001 and P=.006).

CONCLUSIONS

The application of acid-based dentin conditioners significantly improved resin-dentin bond durability under both wet and dry bonding conditions. Furthermore, selective extrafibrillar demineralization dentin conditioners demonstrated remarkable effectiveness in improving resin-dentin bond durability under dry bonding conditions; however, more data are needed to support their use.

Diagnostic Strategies for Restorations Management: A 70-Month RCT

We aimed to evaluate the impact of 2 visual diagnostic strategies for assessing secondary caries and managing permanent posterior restorations on long-term survival. We conducted a diagnostic cluster-randomized clinical trial with 2 parallel groups using different diagnostic strategies: (C+AS) based on caries assessment, marginal adaptation, and marginal staining aspects of the FDI (World Dental Federation) criteria and (C) based on caries assessment using the Caries Associated with Restorations or Sealants (CARS) criteria described by the International Caries Detection and Assessment System (ICDAS). The treatment for the restoration was conducted based on the decision made following the allocated diagnostic strategy. The restorations were then clinically reevaluated for up to 71 mo. The primary outcome was restoration failure (including tooth-level failure: pain, endodontic treatment, and extraction). Cox regression analyses with shared frailty were conducted in the intention-to-treat population, and hazard ratios (HRs) and 95% confidence intervals (95% CIs) were derived. We included 727 restorations from 185 participants and reassessed 502 (69.1%) restorations during follow-up. The evaluations occurred between 6 and 71 mo. At baseline, C led to almost 4 times fewer interventions compared with the C+AS strategy. A total of 371 restorations were assessed in the C group, from which 31 (8.4%) were repaired or replaced. In contrast, the C+AS group had 356 restorations assessed, from which 113 (31.7%) were repaired or replaced. During follow-up, 34 (9.2%) failures were detected in the restorations allocated to the C group and 30 (8.4%) allocated to the C+AS group in the intention-to-treat population, with no significant difference between the groups (HR = 0.83; 95% CI = 0.51 to 1.38; P = 0.435, C+AS as reference). In conclusion, a diagnostic strategy focusing on marginal defects results in more initial interventions but does not improve longevity over the caries-focused strategy, suggesting the need for more conservative approaches.

The influence of copper-doped mesoporous bioactive nanospheres on the temperature rise during polymerization, polymer cross-linking density, monomer release and embryotoxicity of dental composites

OBJECTIVES

Composites with copper-doped mesoporous bioactive nanospheres (Cu-MBGN) were developed to prevent secondary caries by imparting antimicrobial and ion-releasing/remineralizing properties.

METHODS

Seven experimental composites containing 1, 5 or 10 wt% Cu-MBGN, the corresponding inert controls (silica) and bioactive controls (bioactive glass 45S5) were prepared. The temperature rise during light curing, cross-linking density by ethanol softening test, monomer elution and their potential adverse effects on the early development of zebrafish Danio rerio was investigated.

RESULTS

Materials combining Cu-MBGN and silica showed the highest resistance to ethanol softening, as did the bioactive controls. Cu-MBGN composites showed significant temperature rise and reached maximum temperature in the shortest time. Bisphenol A was not detected, while bis-GMA was found only in the control materials and TEGDMA in the eluates of all materials. There was no increase in zebrafish mortality and abnormality rates during exposure to the eluates of any of the materials.

CONCLUSIONS

The composite with 5 wt% Cu-MBGN combined with nanosilica fillers showed the lowest ethanol softening, indicating the polymer's highest durability and cross-linking density. Despite the TEGDMA released from all tested materials, no embryotoxic effect was observed.

A Historical Perspective on Dental Composite Restorative Materials

This review article will discuss the origin of resin-based dental composite materials and their adoption as potentially useful adjuncts to the primary material used by most dentists for direct restorations. The evolution of the materials, largely driven by the industry's response to the needs of dentists, has produced materials that are esthetic, strong, and versatile enough to be used in most areas of the oral cavity to replace or restore missing tooth structures. Significant advancements, such as the transition from chemical to light-curing materials, refinements in reinforcing particles to produce optimum polishing and wear resistance, formulating pastes with altered viscosities to create highly flowable and highly stiff materials, and creating materials with enhanced depth of cure to facilitate placement, will be highlighted. Future advancements will likely reflect the movement away from simply being a biocompatible material to one that is designed to produce some type of beneficial effect upon interaction within the oral environment. These new materials have been called "bioactive" by virtue of their potential effects on bacterial biofilms and their ability to promote mineralization of adjacent tooth structures.

Performance of low shrinkage Bis-EFMA based bulk-fill dental resin composites

OBJECTIVES

The purpose of this study was evaluating the performance of new Bis-EFMA based bulk-fill composites with common methacrylate based composites and commercial dental composites.

METHODS

The Bis-EFMA monomer was synthesized and the novel Bis-EFMA based bulk-fill composites were prepared. The resin composite samples were co-cultured with human gingival epithelial cells and human dental pulp stem cells to test the biocompatibility. The edge adaptation was observed under a combination of stereoscope and scanning electron microscope. The internal hardness was measured using a Vickers microhardness tester after one-time filling of cavities prepared in extracted teeth. After friction and wear test on the surface of the resin composites, the surface morphology and volume wear of each group were measured by the optical profilometer. The color stability was measured by a colorimeter.

RESULTS

Direct contact with human gingival epithelial cells and human dental pulp stem cells did not cause significant changes in their growth density and morphology, indicating good biocompatibility of Bis-EFMA group (p > 0.05). The continuous margin proportion of the Bis-EFMA group was as good as commercial bulk-fill composites (p > 0.05). The sectional microhardness results showed that the Bis-EFMA group had the highest microhardness. After the friction and wear test, the volume wear of the Bis-EFMA group was minimal, indicating its good wear resistance and mechanical strength. Color changes in all resin groups after 28 days of immersion were within the clinically acceptable range.

SIGNIFICANCE

The addition of Bis-EFMA demonstrated excellent biocompatibility, edge adaptation and color stability comparable to commonly used clinical bulk-fill composites, along with preferable mechanical strength, friction and wear resistance. Bis-EFMA based bulk-fill composites have the potential to be employed as a bulk filling material in commercial dental composite applications.

Challenges in conducting clinical research in primary care dentistry

The integration of dentistry into primary health care is crucial for promoting patient well-being. However, clinical studies in dentistry face challenges, including issues with study design, transparency, and relevance to primary care. Clinical trials in dentistry often focus on specific issues with strict eligibility criteria, limiting the generalizability of findings. Randomized clinical trials (RCTs) face challenges in reflecting real-world conditions and using clinically relevant outcomes. The need for more pragmatic approaches and the inclusion of clinically relevant outcomes (CROs) is discussed, such as tooth loss or implant success. Solutions proposed include well-controlled observational studies, optimized data collection tools, and the integration of artificial intelligence (AI) for predictive modelling, computer-aided diagnostics and automated diagnosis. In this position paper advocates for more efficient trials with a focus on patient-centred outcomes, as well as the adoption of pragmatic study designs reflecting real-world conditions. Collaborative research networks, increased funding, enhanced data retrieval, and open science practices are also recommended. Technology, including intraoral scanners and AI, is highlighted for improving efficiency in dental research. AI is seen as a key tool for participant recruitment, predictive modelling, and outcome evaluation. However, ethical considerations and ongoing validation are emphasized to ensure the reliability and trustworthiness of AI-driven solutions in dental research. In conclusion, the efficient conduct of clinical research in primary care dentistry requires a comprehensive approach, including changes in study design, data collection, and analytical methods. The integration of AI is seen as pivotal in achieving these objectives in a meaningful and efficient way.

5.5-year-survival of CAD/CAM resin-based composite restorations in severe tooth wear patients

OBJECTIVES

Aim of this prospective study was to assess full mouth rehabilitation of severe tooth wear patients using minimally invasive CAD/CAM resin-based composite (RBC) restorations and direct veneers by evaluating restoration survival up to 5.5-years.

METHODS

Twenty-two patients with generalized severe tooth wear with functional and/or esthetic problems were included. Following minimally invasive preparation, CAD/CAM RBC restorations (LAVA Ultimate,3M) were adhesively luted, direct RBC veneers (Filtek Supreme XTE, 3M) were applied in the aesthetic region. Patients were recalled after 1m,1y,3y,5y and seen in between recalls by their general dentists or at the clinical study center if complaints occurred. Failures were categorized as F1 (severe deficiencies requiring replacement/extraction), F2 (localized deficiencies requiring re-cementation/repair) and F3 (small chippings requiring refurbishment/monitoring). Survival of indirect restorations was evaluated using lifetables and Kaplan-Meier-graphs, distinguishing between failure categories and tooth type (front teeth=FT, premolars=PM, molars=M). F1 + F2 and F1 + F2 + F3 failures were analyzed using Cox regression on the variables tooth type/ location, age, gender and VDO increase (p < 0.05).

RESULTS

568 indirect restorations and 200 direct veneers in 21 patients evaluated for up to 5.5-years. For indirect restorations, 96 failures were recorded (F1:6;F2:41;F3:49) and annual failure rates were 0.29%(FT), 1.56%(PM), 2.93%(M) for F1 +F2 and 0.53%(FT), 2.42%(PM), 6.11%(M) for F1 + F2 + F3. Reasons for failure were chipping fracture (48), adhesive fracture (32), complete debonding (7), caries (4), endodontic treatment (1) and reasons unknown (documentation general dentists, 4). Molar tooth type had a statistically significantly increased probability of failure compared with front teeth and premolars for F1 + F2 + F3 (p < 0.006). Direct veneer restorations showed 18 failures (F1:2;F2:9;F3:7).

SIGNIFICANCE

Minimally invasive CAD/CAM RBC restorations combined with direct RBC veneers showed an acceptable clinical mid-term survival for restorative rehabilitation of severely worn dentitions.

Longevity of composite restorations in posterior teeth placed by dental students: a 12-year retrospective study

OBJECTIVES

To evaluate the longevity of resin composite restorations placed in posterior teeth by dental students, using data from electronic records from 2008 to 2019.

MATERIALS AND METHODS

Demographic (gender and age) and clinical variables (dental group, position in dental arch, and the number of restored surfaces) were evaluated. The 5-year follow-up was assessed according to the day the restoration was placed. Kaplan-Meier curves were generated to calculate the annual failure rate. Data were analyzed by Chi-Square, Kruskal-Wallis, and Mann-Whitney tests (α = 0.05).

RESULTS

In total, 3.883 records relative to return periodicity were analyzed. The final sample consisted of 900 restorations from 479 patients. The majority were females, aged between 31 and 60. In total, 256 failures were reported (success rate = 78%), showing an annual failure rate of 2.05%. The main reasons for failures were restoration replacement (55.5%), endodontics (21.9%), prosthetics (14.5%) and extraction (8.2%). There was a higher risk of failure in restorations involving three or more surfaces (p = 0.000) and in patients over 60 years (p < 0.001). In females (p = 0.030), molars (p = 0.044), and maxillary teeth (p = 0.038) failed in a shorter time.

CONCLUSIONS

Resin composite restorations placed in permanent posterior teeth by dental students had high survival rates. The main reason for failure was the replacement of restorations. The age group and the number of restored surfaces significantly affected the success of the restorations.

CLINICAL RELEVANCE

The electronic health records over 12 years showed that 78% of the resin restorations in posterior teeth placed by dental students were successful for a minimum of five years.

Clinical evaluation of posterior restorations over wet and dry dentin using an etch-and-rinse adhesive: A 36-month randomized clinical trial

OBJECTIVES

To evaluate the clinical performance of posterior restorations over wet and dry dentin with an etch-and-rinse adhesive after 36 months of clinical service.

METHODS

Forty-five participants were recruited, each one had at least two posterior teeth that needed restoration. Ninety restorations were placed on Class I or Class II cavities. For the restoration protocol, a simplified etch-and-rinse adhesive (Adper Single Bond 2) was applied over wet (WD) or dry dentin (DD) and later restored with a bulk-fill composite (Filtek Bulk Fill) under rubber dam isolation. Each restoration was evaluated using the World Dental Federation (FDI) criteria after 6, 12, and 36 months of clinical service, regarding the following principal restoration characteristics: postoperative sensitivity, marginal discoloration, marginal adaptation, fracture of material and retention, and recurrence of caries. Kruskal Wallis analysis of variance rank (α = 0.05) and Kaplan-Meier survival analysis were used for statistical analysis.

RESULTS

After 36 months of clinical evaluation, no significant difference between groups was observed in each FDI criterion (p > 0.05). Twenty restorations (WD=10, DD=10) showed minor marginal staining, and twenty-two restorations (WD=11, DD=11) presented small marginal adaptation defects (p > 0.05). Four restorations were lost (WD = 2, DD = 2) and the fracture rates (95% confidence interval) were 94.9% for each one, without significant difference between wet and dry dentin (p > 0.05).

SIGNIFICANCE

The degree of dentin moisture does not seem to affect the clinical performance of a simplified etch-and-rinse adhesive in posterior restorations when the adhesive is applied vigorously over the dentine surface.

Detection of caries around restorations on bitewings using deep learning

OBJECTIVE

Secondary caries lesions adjacent to restorations, a leading cause of restoration failure, require accurate diagnostic methods to ensure an optimal treatment outcome. Traditional diagnostic strategies rely on visual inspection complemented by radiographs. Recent advancements in artificial intelligence (AI), particularly deep learning, provide potential improvements in caries detection. This study aimed to develop a convolutional neural network (CNN)-based algorithm for detecting primary caries and secondary caries around restorations using bitewings.

METHODS

Clinical data from 7 general dental practices in the Netherlands, comprising 425 bitewings of 383 patients, were utilized. The study used the Mask-RCNN architecture, for instance, segmentation, supported by the Swin Transformer backbone. After data augmentation, model training was performed through a ten-fold cross-validation. The diagnostic accuracy of the algorithm was evaluated by calculating the area under the Free-Response Receiver Operating Characteristics curve, sensitivity, precision, and F1 scores.

RESULTS

The model achieved areas under FROC curves of 0.806 and 0.804, and F1-scores of 0.689 and 0.719 for primary and secondary caries detection, respectively.

CONCLUSION

An accurate CNN-based automated system was developed to detect primary and secondary caries lesions on bitewings, highlighting a significant advancement in automated caries diagnostics.

CLINICAL SIGNIFICANCE

An accurate algorithm that integrates the detection of both primary and secondary caries will permit the development of automated systems to aid clinicians in their daily clinical practice.

Shedding light on the problem: Proficiency and maintenance practices of light-curing units among dental assistants

BACKGROUND

Proper light curing is crucial for the success of restorative dentistry and to bond brackets to teeth, yet the responsibility is often delegated to dental assistants (DAs). This study assessed the proficiency and maintenance protocols of DAs when using light-curing units (LCUs) in Saudi Arabia.

METHODS

Self-administered questionnaires were distributed to practicing DAs. The questionnaire contained sections on knowledge, adherence to best practices, and how to maintain the LCU. Demographic data were collected as well. Descriptive statistics and linear regressions at a significance level of (p = 0.05) were conducted to identify any relationships that influenced the DAs' LCU knowledge, practice, and maintenance protocols.

RESULTS

Among the surveyed DAs, 66% were responsible for using the LCU during treatment, 16% used their fingers for support when light curing, 50% held the LCU tip 1-2 mm from the restoration during curing, and 51% did not have a specific maintenance protocol at their workplace. 70% did not know the output from the LCU, and their educational background correlated with knowledge (b = -14.42, p < 0.001). The type of institution type correlated with adherence to best practices (b = -13.65, p = 0.011), and level of knowledge and adherence to maintenance protocols showed a direct correlation (b = 0.002, p = 0.041).

CONCLUSIONS

The findings revealed that a significant percentage of the DAs who replied had insufficient knowledge and did not follow the best practices and maintenance protocols for the LCUs they were using. Their educational background and workplace factors influenced this knowledge gap, while the absence of a maintenance protocol and suboptimal practices were associated with the type of institution.

CLINICAL SIGNIFICANCE

To maintain the best practice, clinicians and institutions should improve the education and training of DAs. Otherwise, inadequate light curing by the DAs may jeopardize the long-term success of many dental procedures.

The power of light - From dental materials processing to diagnostics and therapeutics

Harnessing the power of light and its photonic energy is a powerful tool in biomedical applications. Its use ranges from biomaterials processing and fabrication of polymers to diagnostics and therapeutics. Dental light curable materials have evolved over several decades and now offer very fast (≤ 10 s) and reliable polymerization through depth (4-6 mm thick). This has been achieved by developments on two fronts: (1) chemistries with more efficient light absorption characteristics (camphorquinone [CQ], ~30 L mol-1 cm1 [ʎmax 470 nm]; monoacylphosphine oxides [MAPO], ~800 L mol-1 cm-1 [ʎmax 385 nm]; bisacylphosphine oxide [BAPO], ~1,000 L mol-1 cm-1 [ʎmax 385 nm]) as well mechanistically efficient and prolonged radical generation processes during and after light irradiation, and; (2) introducing light curing technologies (light emitting diodes [LEDs] and less common lasers) with higher powers (≤ 2 W), better spectral range using multiple diodes (short: 390-405 nm; intermediate: 410-450 nm; and long: 450-480 nm), and better spatial power distribution (i.e. homogenous irradiance). However, adequate cure of materials falls short for several reasons, including improper selection of materials and lights, limitations in the chemistry of the materials, and limitations in delivering light through depth. Photonic energy has further applications in dentistry which include transillumination for diagnostics, and therapeutic applications that include photodynamic therapy, photobiomodulation, and photodisinfection. Light interactions with materials and biological tissues are complex and it is important to understand the advantages and limitations of these interactions for successful treatment outcomes. This article highlights the advent of photonic technologies in dentistry, its applications, the advantages and limitations, and possible future developments.

Influence of surface sealants on the quality of posterior restorations with bulk-fill composites: A 4-year randomized clinical trial

OBJECTIVES

The aim of this study was to evaluate the clinical performance of surface sealants associated with a bulk-fill composite in posterior restorations after 4 years.

METHODS

A total of 174 posterior restorations were performed on 57 participants using a self-etch adhesive system and a bulk-fill composite. The groups were then divided into the following categories: 1) without surface sealant (NoS), 2) with surface sealant Biscover (Bisco, SBi), and 3) with surface sealant Permaseal (Ultradent, SPe). Restorations were evaluated using FDI criteria at baseline and after 1 and 4 years. Statistical analysis was conducted using Kaplan-Meier survival analysis and the Chi-square test (α = 0.05).

RESULTS

After 4 years, only one restoration was lost (1 in the NoS group). The fracture/retention rate (with 95% confidence interval) was 98% for NoS and 100% for both SBi and SPe (p = 0.76). The majority of secondary outcomes showed minor defects, with no significant differences among the groups (p > 0.05). However, significant differences were observed among the groups in terms of marginal staining and marginal adaptation (p = 0.03). In both items, twelve restorations (nine in NoS, one in SBi, and two in SPe) showed minor marginal discrepancies favoring the sealant groups (SBi and SPe).

SIGNIFICANCE

Regardless of the use of surface sealants, the bulk-fill composite restorations showed excellent clinical performance after 4 years. However, the groups that received sealants showed better marginal adaptation and less marginal discoloration compared to those that did not receive sealants.

Current trends in placing posterior composite restorations: Perspectives from Palestinian general dentists: A questionnair study

Aim

The success of composite restorations relies on material selection and practitioner-related factors that shape the overall outcome. This study explores the practices of Palestinian general dental practitioners in placing posterior composites, examining the impact of work sector, experience, and gender on their choices.

Materials and Methods

The study was conducted as an online cross-sectional questionnaire and involved 351 participants, with a response rate of 69.8%. The survey comprised 18 closed-ended questions covering demographics, material selection, and composite placement in special cases, techniques, and factors influencing the choices. Statistical analyses included descriptive statistics, chi-squared tests, and Fisher's exact tests.

Results

Composite was the predominant choice for small-size (83.7%) and large-size posterior cavities (60.4%). Practitioners commonly opted for composite restorations in cases involving occlusal parafunctional activity (60%), poor oral hygiene (78%), and subgingival cavities (72.2%). Only 19.6% and 5.3% reported occlusal and gingival beveling, respectively. Rubber dams for isolation stood at 30%, one-step self-etch adhesives at 44.9%, and the oblique layering technique at 51%. Light-emitting diode curing units were popular (97.55%), but monitoring output with a radiometer was infrequent (93.5%). Tofflemire metal matrix usage was 46.1%, whereas a sectional matrix system was employed by 29.8%. A 2 mm layer exposure to light curing for 20 s was reported by 62%, and 27.75% utilized additional light-curing postmatrix band removal.

Conclusion

The study highlights the need for Palestinian dental professionals to update their clinical approaches in placing composite restorations in posterior teeth. Gender, work sector, and experience influence practitioners' choices, emphasizing the importance of tailored continuing education programs for improving clinical practices.

Longevity of dental restorations in Sjogren's disease patients using electronic dental and health record data

BACKGROUND

Decreased salivary secretion is not only a risk factor for carious lesions in Sjögren's disease (SD) but also an indicator of deterioration of teeth with every restorative replacement. This study determined the longevity of direct dental restorations placed in patients with SD using matched electronic dental record (EDR) and electronic health record (EHR) data.

METHODS

We conducted a retrospective cohort study using EDR and EHR data of Indiana University School of Dentistry patients who have a SD diagnosis in their EHR. Treatment history of patients during 15 years with SD (cases) and their matched controls with at least one direct dental restoration were retrieved from the EDR. Descriptive statistics summarized the study population characteristics. Cox regression models with random effects analyzed differences between cases and controls for time to direct restoration failure. Further the model explored the effect of covariates such as age, sex, race, dental insurance, medical insurance, medical diagnosis, medication use, preventive dental visits per year, and the number of tooth surfaces on time to restoration failure.

RESULTS

At least one completed direct restoration was present for 102 cases and 42 controls resulting in a cohort of 144 patients' EDR and EHR data. The cases were distributed as 21 positives, 57 negatives, and 24 uncertain cases based on clinical findings. The average age was 56, about 93% were females, 54% were White, 74% had no dental insurance, 61% had public medical insurance, < 1 preventive dental visit per year, 94% used medications and 93% had a medical diagnosis that potentially causes dry mouth within the overall study cohort. About 529 direct dental restorations were present in cases with SD and 140 restorations in corresponding controls. Hazard ratios of 2.99 (1.48-6.03; p = 0.002) and 3.30 (1.49-7.31, p-value: 0.003) showed significantly decreased time to restoration failure among cases and positive for SD cases compared to controls, respectively. Except for the number of tooth surfaces, no other covariates had a significant influence on the survival time.

CONCLUSION

Considering the rapid failure of dental restorations, appropriate post-treatment assessment, management, and evaluation should be implemented while planning restorative dental procedures among cases with SD. Since survival time is decreased with an increase in the number of surfaces, guidelines for restorative procedures should be formulated specifically for patients with SD.

Survival analysis of posterior composite restorations in National Dental PBRN general dentistry practices

OBJECTIVE

Quantify the survival of posterior composite restorations (PCR) placed during the study period in permanent teeth in United States (US) general dental community practices and factors predictive of that survival.

METHODS

A retrospective cohort study was conducted utilizing de-identified electronic dental record (EDR) data of patients who received a PCR in 99 general dentistry practices in the National Dental Practice-Based Research Network (Network). The final analyzed data set included 700,885 PCRs from 200,988 patients. Descriptive statistics and Kaplan Meier (product limit) estimator were performed to estimate the survival rate (defined as the PCR not receiving any subsequent treatment) after the first PCR was observed in the EDR during the study time. The Cox proportional hazards model was done to account for patient- and tooth-specific covariates.

RESULTS

The overall median survival time was 13.3 years. The annual failure rates were 4.5-5.8 % for years 1-5; 5.3-5.7 %, 4.9-5.5 %, and 3.3-5.2 % for years 6-10, 11-15, and 16-20, respectively. The failure descriptions recorded for < 7 % failures were mostly caries (54 %) and broken or fractured tooth/restorations (23 %). The following variables significantly predicted PCR survival: number of surfaces that comprised the PCR; having at least one interproximal surface; tooth type; type of prior treatment received on the tooth; Network region; patient age and sex. Based on the magnitude of the multivariable estimates, no single factor predominated.

CONCLUSIONS

This study of Network practices geographically distributed across the US observed PCR survival rates and predictive factors comparable to studies done in academic settings and outside the US.

CLINICAL SIGNIFICANCE

Specific baseline factors significantly predict the survival of PCRs done in US community dental practices.

Internal Adaptation of Composite Fillings Made Using Universal Adhesives-A Micro-Computed Tomography Analysis

This study aimed to evaluate internal tooth-filling interfaces of composite fillings made using universal adhesives using micro-computed tomography (µCT). Sixty class V cavities were randomly assigned into six groups: Peak Universal etch and rinse (PER), Peak Universal self-etch (PSE), Adhese Universal etch and rinse (AER), and Adhese Universal self-etch (ASE). Two further adhesives considered gold standards were used as control groups: OptiBond FL (OER) for the etch and rinse technique and Clearfil SE for the self-etch technique (CSE). All teeth were subjected to thermomechanical loading and four-year water storage. Next, they were analyzed using µCT to investigate the internal tooth-filling interfaces. The proportions between the gap volume (GV) at the tooth-filling interface and the volume of applied composite filling (FV), between the gap and cavity volumes (CV), and between the gap volumes at the tooth-filling interface of the external (EGV) and internal (IGV) parts were calculated. Adhese Universal achieved the significantly lowest gap-to-filling- and gap-to-cavity-volume ratios for both types of etching techniques comparing to those of the Peak Universal and control groups. Significant differences between the gaps in external and internal parts of the tooth-filling interface were only noted in the control groups. Internal gap formation and development at the tooth-filling interface depend on the material as well as the type of its application.

Color Match of a Universal-shade Composite Resin for Restoration of Non-carious Cervical Lesions: An Equivalence Randomized Clinical Trial

PURPOSE

The objective of this double-blind, split-mouth, randomized clinical trial was to evaluate the color match of a single-shade composite resin Admira Fusion X-tra in comparison with a multi-shade composite resin Admira Fusion in non-carious cervical lesion restorations (NCCLs).

METHODS AND MATERIALS

One hundred and twenty restorations were performed on NCCLs with two restorative materials (n=60). After prophylaxis, the teeth were isolated with a rubber dam, and one universal adhesive was applied in the selective enamel etching strategy. For both groups, the restorations were inserted incrementally and light-cured. The values of the coordinates L*, a*, and b* in the cervical third before vs after the restorations and cervical vs middle third after the restorations were evaluated using a digital spectrophotometer after the coordinate values were used to calculate the CIEDE (ΔE00). The restorations were evaluated at baseline and after 7 days of clinical performance according to the FDI criteria. Statistical analysis was performed using the Chi-square test for all parameters. Color change was analyzed by Student t-test for paired samples (α=0.05).

RESULTS

All restorations were evaluated after 7 days. Regarding the color measurement, no significant difference was observed when Admira Fusion was compared to Admira Fusion X-tra for any of the comparisons performed (p>0.05). However, the values of ΔE00 in the cervical third before vs after the restorations were higher when compared with ΔE00 observed when the cervical vs middle third after restorations were compared. All restorations received the score "clinically very good" after 7 days for all outcomes, including the subjective color match, when evaluated for FDI criterion.

CONCLUSIONS

The single-shade composite resin used achieves the same color match when compared to a multi-shade composite resin after 7 days in NCCLs.

Hydroxyapatite-based dental inserts: Microstructure, mechanical properties, bonding efficiency and fracture resistance of molars with occlusal restorations

This study aimed to (1) comparatively analyze properties of Sr- and Mg-substituted hydroxyapatite (HAP)-based dental inserts; (2) evaluate insert bonding to restorative materials, and (3) evaluate the effect of doped HAP inserts on fracture resistance (FR) of human molars with large occlusal restorations. By ion-doping with Sr or Mg, 3 insert types were obtained and characterized using XRD, SEM, Vickers hardness and fracture toughness. Shear bond strength (SBS) was determined between acid etched or unetched inserts and following materials: Maxcem cement (Kerr); Filtek Z250 (3M) bonded with Single Bond Universal (SBU; 3M) or Clearfil Universal (Cf; Kuraray). Modified Class I cavities were prepared in 16 intact molars and restored using insert + composite or composite only (control) (n = 8/group). FR of restored molars was determined by static load until fracture upon thermal cycling. Fracture toughness was similar between Sr/Mg-doped inserts (0.94-1.04 MPam-1/2 p = .429). Mg-doped inserts showed greater hardness (range 4.78-5.15 GPa) than Sr6 inserts (3.74 ± 0.31 GPa; p < .05). SBS for SBU and Cf adhesives (range 7.19-15.93 MPa) was higher than for Maxcem (range 3.07-5.95 MPa) (p < .05). There was no significant difference in FR between molars restored with insert-containing and control restorations (3.00 ± 0.30 kN and 3.22 ± 0.42 kN, respectively; p > .05). HAP-based inserts doped with Mg/Sr had different composition and mechanical properties. Adhesive bonding to inserts resulted in greater bond strength than cementation, which may be improved by insert acid-etching. Ion-doped HAP inserts did not affect FR of restored molars. In conclusion, HAP-based dental inserts may potentially replace dentin in large cavities, without affecting fracture resistance of restored teeth.

Considerations about Cytotoxicity of Resin-Based Composite Dental Materials: A Systematic Review

The dental material industry is rapidly developing resin-based composites (RBCs), which find widespread use in a variety of clinical settings. As such, their biocompatibility has gained increasing interest. This literature review presents a summary of research into the cytotoxicity of methacrylate-based composites published from 2017 to 2023. Subject to analysis were 14 in vitro studies on human and murine cell lines. Cytotoxicity in the included studies was measured via MTT assay, LDH assay, and WST-1 assay. The QUIN Risk of Bias Tool was performed to validate the included studies. Included studies (based entirely on the results of in vitro studies) provide evidence of dose- and time-dependent cytotoxicity of dental resin-based composites. Oxidative stress and the depletion of cellular glutathione (GSH) were suggested as reasons for cytotoxicity. Induction of apoptosis by RBCs was indicated. While composites remain the golden standard of dental restorative materials, their potential cytotoxicity cannot be ignored due to direct long-term exposure. Further in vitro investigations and clinical trials are required to understand the molecular mechanism of cytotoxicity and produce novel materials with improved safety profiles.

Clinical longevity of direct and indirect posterior resin composite restorations: An updated systematic review and meta-analysis

OBJECTIVES

To answer the PICO(S) question: Is there a difference in clinical longevity between direct and indirect resin composite restorations placed on permanent posterior teeth?

DATA

Randomized controlled clinical trials (RCTs) investigating direct and indirect resin composite restorations in posterior permanent teeth were considered.

SOURCES

Several electronic databases were searched, with no language or date restrictions. The revised Cochrane Collaboration's tool for assessing risk of bias (RoB-2) was used to analyze the studies; meta-analyses were run and the certainty of evidence was assessed by the GRADE tool. A subgroup meta-analysis was performed for resin composite restorations placed on posterior worn dentition.

STUDY SELECTION

Twenty-three articles were included in qualitative synthesis, while 8 studies were used for meta-analyses. According to the RoB-2 tool, 5 studies were ranked as "low risk", 7 had "some concerns", while 11 papers were rated as "high risk" of bias. There were no statistically significant differences in short-term (p = 0.27; RR=1.54, 95% CI [0.72, 3.33]), medium-term (p = 0.27; RR=1.87, 95% CI [0.61, 5.72]) and long-term longevity (p = 0.86; RR=0.95, 95% CI [0.57, 1.59]). The choice of restorative technique had no influence on short-term survival of resin composite restorations placed on worn dentition (p = 0.13; RR=0.46, 95% CI [0.17, 1.25]). The certainty of evidence was rated as "very low".

CONCLUSIONS

Direct and indirect resin composite restorations may show similar clinical longevity in posterior region, regardless of the observation period or substrate (wear-affected and non-affected dentition). The very low quality of evidence suggests that more long-term RCTs are needed to confirm our results.

Clinical evaluation of lithium disilicate versus indirect resin composite partial posterior restorations - A 7.8-year retrospective study

OBJECTIVE

To evaluate retrospectively the longevity of lithium disilicate ceramic (LidiSi) vs. laboratory-processed resin-based composite (RBC) inlay/onlay/overlay restorations and risk factors associated with restoration deficiencies and failures.

METHODS

Patients (n = 91) receiving LidiSi (73.1%) and RBC (36.9%) inlays/onlays/overlays between 2007 and 2017 were selected. The restorations were evaluated using the modified U.S. Public Health Service criteria. The survival of the restorations was analyzed using the Kaplan-Meier method and log rank test. Factors affecting the occurrence of deficiencies were examined by logistic regression analysis. This was performed with the use of the Generalized Estimating Equation model including Repeated measurements (GEER), with the consideration that the same patient had several teeth in the sample. Risk estimation was conducted for each evaluated criterion (p < 0.05).

RESULTS

The survival of LidiSi and RBC restorations were 96.8% and 84.9%, respectively after a mean observation period of 7.8 ± 3.3 years. The annual failure rate was 0.2% for LidiSi and 1.0% for RBC. The probability of survival was above 98% for both restorations in the first 6 years, however, it dropped to 60% for RBC by the end of the 15th year. For both materials the reasons for failure included secondary caries, restoration fracture, and endodontic complication. In addition, LidiSi also failed due to tooth fracture, while RBC due to marginal gap formation and loss of retention. Among the evaluated risk factors, material of restoration (OR=6.8, CI95%:3.1-14.9), oral hygiene (OR=8.0, CI95%: 2.9-22.1], and bruxism (OR=1.9, CI95%: 1.1-3.3) showed a significant impact on the evaluated criteria.

SIGNIFICANCE

LidiSi and RBC restorations showed similarly excellent 6-year survival, however, in the long term significantly more failures should be expected for RBCs.

Probing the micro- and nanoscopic properties of dental materials using infrared spectroscopy: A proof-of-principle study

The preservation of oral health over a person's lifespan is a key factor for a high quality of life. Sustaining oral health requires high-end dental materials with a plethora of attributes such as durability, non-toxicity and ease of application. The combination of different requirements leads to increasing miniaturization and complexity of the material components such as the composite and adhesives, which makes the precise characterization of the material blend challenging. Here, we demonstrate how modern IR spectroscopy and imaging from the micro- to the nanoscale can provide insights on the chemical composition of the different material sections of a dental filling. We show how the recorded IR-images can be used for a fast and non-destructive porosity determination of the studied adhesive. Furthermore, the nanoscale study allows precise assessment of glass cluster structures and distribution within their characteristic organically modified ceramic (ORMOCER) matrix and an assessment of the interface between the composite and adhesive material. For the study we used a Fourier-Transform-IR (FTIR) microscope and a quantum cascade laser-based IR-microscope (QCL-IR) for the microscale analysis and a scattering-type scanning near-field optical microscopy (s-SNOM) for the nanoscale analysis. The paper ends with an in-depth discussion of the strengths and weaknesses of the different imaging methods to give the reader a clear picture for which scientific question the microscopes are best suited for. STATEMENT OF SIGNIFICANCE: Modern resin-based composites for dental restoration are complex multi-compound materials. In order to improve these high-end materials, it is important to investigate the molecular composition and morphology of the different parts. An emergent method to characterize these materials is infrared spectroscopic imaging, which combines the strength of infrared spectroscopy and an imaging approach known from optical microscopy. In this work, three state of the art methods are compared for investigating a dental filling including FTIR- and quantum cascade laser IR-imaging microscopy for the microscale and scattering-type scanning near-field optical microscopy for the nanoscale.

Compositional boundaries for functional dental composites containing calcium orthophosphate particles

OBJECTIVES

To investigate the interrelationships among handling, degree of conversion (DC), mechanical behavior and Ca2+ release of composites containing dicalcium phosphate dihydrate (DCPD, CaHPO4.2H2O), as a function of total inorganic content and DCPD: glass ratio.

METHODS

Twenty-one formulations (1 BisGMA: 1 TEGDMA, in mols) with inorganic fractions ranging from zero to 50 vol% and different DCPD: glass ratios were evaluated for viscosity (parallel plate rheometer, n = 3), DC (near-FTIR spectroscopy, n = 3), fracture toughness/K1C (single-edge notched beam, n = 7-11) and 14-day Ca2+ release (inductively coupled plasma optical emission spectroscopy, n = 3). Data were analyzed by ANOVA/Tukey test (except viscosity, where Kruskal-Wallis/Dunn tests were used, α: 0.05).

RESULTS

Viscosity and DC increased with DCPD: glass ratio among composites with the same inorganic content (p < 0.001). At inorganic fractions of 40 vol% and 50 vol%, keeping DCPD content at a maximum of 30 vol% did not compromise K1C. Ca2+ release showed an exponential relationship with DCPD mass fraction in the formulation (R2 = 0.986). After 14 days, a maximum of 3.8% of the Ca2+ mass in the specimen was released.

CONCLUSION

Formulations containing 30 vol% DCPD and 10-20 vol% glass represent the best compromise between viscosity, K1C and Ca2+ release. Materials with 40 vol% DCPD should not be disregarded, bearing in mind that Ca2+ release will be maximized at the expense of K1C.

Microleakage of Restorative Materials Used for Temporization of Endodontic Access Cavities

A tight temporary seal applied to an access cavity is thought to improve endodontic outcomes. This study aims to assess the bacterial and glucose microleakage of different types and combinations of temporary restorations. Human-extracted incisors were instrumented, dressed with a calcium hydroxide paste, and sealed with Cavit W (CW), CW/Ketac Molar (CW/KM), CW/Smart Dentin Replacement (CW/SDR), Intermediate restorative material/KM (IRM/KM), or Clip F (CF). Standardized 3D-printed hollow test specimens were manufactured and temporized in the same manner. The specimens were examined for bacterial and glucose leakage for 28 days. Data were analyzed using a Kaplan-Meier survival analysis. CW/SDR and CF showed the least bacterial and glucose leakage over time. CW, CW/KM, and IRM/KM had similarly high levels of glucose leakage, but CW/KM and IRM/KM provided a tighter seal against bacterial penetration than CW. CW/SDR and CF should be considered for the sealing of access cavities of teeth previously restored with methacrylate-based materials.

Evaluation of contact angle and mechanical properties of resin monomers filled with graphene oxide nanofibers

This in vitro study synthesized hybrid nanofibers embedded in graphene oxide (GO) and incorporated them into experimental resin composite monomers to evaluate their physical-mechanical properties. Inorganic-organic hybrid nanofibers were produced with precursor solutions of 1% wt. GO-filled Poly (d,l-lactide, PLA) fibers and scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) characterized the morphology and chemical composition of the spun fibers. Resin composite monomers were developed and a total of 5% nanofibers were incorporated into the experimental materials. Three groups were developed: G1 (control resin monomers), G2 (resin monomers/PLA nanofibers), and G3 (resin monomers/inorganic-organic hybrid nanofibers). Contact angle (n=3), flexural strength (n=22), elastic modulus (n=22), and Knoop hardness (n=6) were evaluated. The mean of the three indentations was obtained for each sample. The normality of data was assessed by QQ Plot with simulated envelopes and analyzed by Welch's method (p<0.05). Overall, SEM images showed the regular shape of nanofibers but were non-aligned. Compositional analysis from EDS (n=6) revealed the presence of carbon and oxygen (present in GO composition) and Si from the functionalization process. The results of contact angle (°) and hardness (Kg/mm2) for each group were as follow, respectively: G1 (59.65±2.90; 37.48±1.86a), G2 (67.99±3.93; 50.56±1.03b) and G3 (62.52±7.40; 67.83±1.01c). The group G3 showed the highest Knoop hardness values (67.83 kg/mm2), and the flexural strength of all groups was adversely affected. The experimental resin composite composed of hybrid nanofibers with GO presented increased hardness values and hydrophilic behavior.

Injectable Resin Technique as a Restorative Alternative in a Cleft Lip and Palate Patient: A Case Report

Objective: The objective of this study is to present a case report in which the injectable composite resin technique was used as a restorative alternative for dental re-anatomization in a patient with cleft lip and palate and aesthetic complaints. Materials and Methods: The treatment plan included the re-anatomization of the maxillary premolars and canines using a flowable composite resin. This resin was injected and cured through a transparent matrix, which was a copy of the diagnostic wax-up model. Some parameters such as application time and marginal adaptation were also observed when performing the restorations. Additionally, old composite resin restorations on the upper lateral incisors were replaced using the incremental technique with conventional resins, which helped to assess color stability and fracture/wear deterioration for both restorative techniques. Results: The clinical case report shows that the injectable technique was a simple and quick method for restoring the anatomy of teeth (shape and contour) in one session, since the injectable resin can be easily applied in interproximal areas without the need to manually sculpt the resin. In this case, no clinical, visual, or photographic differences were found in marginal discoloration, color stability, and fracture/wear deterioration for the two restorative techniques after one year of follow-up. Conclusions: The professional may have another clinical option for restorative treatment in the case of small re-anatomizations. In addition, the injectable technique seems to require less operator skill and chair time and better marginal adaptation in cases of small anatomical changes.