Activated Charcoal Dental Products: Evidence of Effectiveness Is Lacking.

With society trending toward the avoidance of artificial components, so-called "natural" products have been gaining space and people's attention in recent years. Activated charcoal-based dental products are a prominent example of this movement because of their promise of removal of extrinsic stains or whitening of teeth by a natural means. Such products have gained popularity among patients, and companies have explored this market, launching charcoal-based and activated charcoal-based dentifrices, mouthrinses, toothbrushes, and whitening products that can be easily found at nearby stores and on the internet.1.

Errors in light-emitting diodes positioning when curing bulk fill and incremental composites: impact on properties after aging.

OBJECTIVES: This study aimed to evaluate the effect of improper positioning single-peak and multi-peak lights on color change, microhardness of bottom and top, and surface topography of bulk fill and incremental composites after artificial aging for 1 year. MATERIALS AND METHODS: Bulk fill and incremental composites were cured using multi-peak and single-peak light-emitting diode (LED) following 4 clinical conditions: (1) optimal condition (no angulation or tip displacement), (2) tip-displacement (2 mm), (3) slight tip angulation (α = 20°) and (4) moderate tip angulation (α = 35°). After 1-year of water aging, the specimens were analyzed for color changes (ΔE), Vickers hardness, surface topography (Ra, Rt, and Rv), and scanning electron microscopy. RESULTS: For samples cured by single-peak LED, the improper positioning significantly increases the color change compared to the optimal position regardless of the type of composite (p < 0.001). For multi-peak LED, the type of resin composite and the curing condition displayed a significant effect on ΔE (p < 0.001). For both LEDs, the Vickers hardness and bottom/top ratio of Vickers hardness were affected by the type of composite and the curing condition (p < 0.01). CONCLUSIONS: The bulk fill composite presented greater resistance to wear, higher color stability, and better microhardness than the incremental composite when subjected to improper curing. The multi-peak LED improves curing under improper conditions compared to single-peak LED. Prevention of errors when curing composites requires the attention of all personnel involved in the patient's care once the clinical relevance of the appropriate polymerization reflects on reliable long-term outcomes.

Improper Light Curing of Bulkfill Composite Drives Surface Changes and Increases S. mutans Biofilm Growth as a Pathway for Higher Risk of Recurrent Caries around Restorations.

How dentists cure a resin-based material has deleterious effects on the material's properties and its interaction with surrounding dental tissues. Biofilm accumulation has been implicated in the pathogenesis of carious lesions around dental restorations, with its composition manifesting expressed dysbiosis in patients suffering from dental caries. To evaluate the influence of varying radiant exposure on the degree of conversion (DC%), Streptococcus mutans biofilm growth, and surface roughness of bulk-fill composites under different light-curing conditions. Two light-curing units (LCU) at 600 and 1000 mW/cm2 were used to simulate curing conditions with different angulations (∢20° and ∢35°) or 2 mm-distance displacements of the LCU tip. The radiant exposure (RE) was assessed, and the composites were analyzed for DC%. Biofilm formation was induced over the bulk-fill composites and analyzed via colony-forming units counting and scanning electron microscopy (SEM). The surface roughness was analyzed via a profilometer and SEM after biofilm formation. Curing conditions with different angulation or displacement decreased RE compared to the "optimal condition". The moderately (∢35°) angulated LCU tip and low (600 mW/cm2) radiant emittance significantly reduced the DC% (p < 0.05). The difference in DC% between the top and bottom of the composites ranged from 8 to 11% for 600 mW/cm2 and 10 to 20% for 1000 mW/cm2. Greater S. mutans biofilm and surface changes were found in composites with non-optimal RE delivery (e.g., tip displacement and angulation) (p < 0.05). Inadequate polymerization of bulk-fill composites was associated with more biofilm accumulation and surface topography changes. Overall, non-optimally performed curing procedures reduced the amount of delivered RE, which led to low DC%, more biofilm formation, and higher surface roughness. The improper light-curing of bulk-fill composites compromises their physicochemical and biological properties, which could lead to inferior clinical performance and reduced restorative treatments' longevity.

Hands-on training based on quantifying radiant exposure improves how dental students cure composites: Skill retention at 2-year follow-up.

INTRODUCTION: The durability and longevity of composite restoration are much dependent on the accurate delivery of the energy required to polymerise the material. This study aimed to investigate the extent to which undergraduate dental students acquire and retain light-curing skills following hands-on training. MATERIALS AND METHODS: Hands-on training comprises faculty tutoring for critical aspects of the light-curing procedure, such as distance and angulation of the light-curing tip. Assessments of the students' ability to deliver a specified radiant exposure to class III and I simulated RBCs using a dental simulator (MARC-PS® ) at three different time points after the training. Data were analysed using repeated measure ANOVA. RESULTS: Immediately after the training, students' performance on curing was improved (p < .05). Overall, the radiant exposure increased after training, but the students lost some of the benefits with time. For curing in the anterior section (anterior sensor-class III), the mean radiant exposure values increased by approximately 20% after the training. After 2 years, the values were 15% greater than baseline values. For curing in the posterior section (posterior sensor-class I), the mean radiant exposure values increased by approximately 150% after the training. A significant decrease (p < .05) was observed; however, the radiant exposure values were still 82% greater than the baseline after 2 years. CONCLUSION: A hands-on training dedicated to light-curing procedures facilitated acquisition and retention up to a 2-year follow-up of skill on how light cure composite inside the mouth. The training was more relevant for curing in posterior areas, where orientation can significantly impact light-curing. A hands-on training where the radiant exposure can be measure gave objective measurement metrics to guide the curing performance. This approach is an effective means of teaching practical skills to dental students.

Assessment of the radiant emittance of damaged/contaminated dental light-curing tips by spectrophotometric methods.

OBJECTIVES: This study investigated the effects of physically damaged and resin-contaminated tips on radiant emittance, comparing them with new undamaged, non-contaminated tips using 3 pieces of spectrophotometric laboratory equipment. MATERIALS AND METHODS: Nine tips with damage and/or resin contaminants from actual clinical situations were compared with a new tip without damage or contamination (control group). The radiant emittance was recorded using 3 spectrophotometric methods: a laboratory-grade thermopile, a laboratory-grade integrating sphere, and a portable light collector (checkMARC). RESULTS: A significant difference between the laboratory-grade thermopile and the laboratory-grade integrating sphere was found when the radiant emittance values of the control or damaged/contaminated tips were investigated (p < 0.05), but both methods were comparable to checkMARC (p > 0.05). Regardless of the method used to quantify the light output, the mean radiant emittance values of the damaged/contaminated tips were significantly lower than those of the control (p < 0.05). The beam profile of the damaged/contaminated tips was less homogeneous than that of the control. CONCLUSIONS: Damaged/contaminated tips can reduce the radiant emittance output and the homogeneity of the beam, which may affect the energy delivered to composite restorations. The checkMARC spectrophotometer device can be used in dental offices, as it provided values close to those produced by a laboratory-grade integrated sphere spectrophotometer. Dentists should assess the radiant emittance of their light-curing units to ensure optimal curing in photoactivated, resin-based materials.

Underperforming light curing procedures trigger detrimental irradiance-dependent biofilm response on incrementally placed dental composites.

OBJECTIVES: Insufficient radiant exposure (J/cm2) may provide an early trigger in a cascade of detrimental responses on incrementally-place composite, especially the bottom layer. This study aimed to assess the influence of poor radiant exposure, the degree of conversion (%DC), water sorption/ solubility and S. mutans biofilm formation on conventional, incrementally placed composites and to establish a relationship between these factors. METHODS: Two light units operating at 600 and 1000 mW/cm2 and four most common operator-dependent curing conditions had the radiant exposure (RE) recorded. All the specimens were subjected to S. mutans biofilm model for 14 days. The %DC, biofilm formation expressed by colony-forming units (CFU), water sorption/ solubility and surface roughness/ SEM were assessed. Data were submitted to two-way ANOVA and Tukey post-hoc test (α = 0.05). Pearson correlation was also determined. RESULTS: The influence of RE on S. mutans CFU values and DC are dependent on the curing conditions and irradiance (p < 0.05). A negative relationship was observed between RE and biofilm formation. The operator-dependent curing conditions have shown RE reduction varying from 49.4% to 73.5% in relation to control. The difference in DC between top/bottom of cylinder varied from 13% to 21% for 1000 mW/cm2and from 29% to 53% for LCU600. The roughness, solubility and salivary sorption were greater for low RE. CONCLUSION: Poor, deficient curing procedures provide an early trigger in a negative pathway of events for incrementally-place dental composite including a biological response by increased biofilm formation by S. mutans, a relevant factor for secondary caries development. SIGNIFICANCE: The susceptibility to variation in the outcomes was RE -dependent. The optimization of the curing procedures ensures the maximum performance in the chain of events involved in the light curing process of resin-based materials and potentially reduce the risk factors of secondary caries development.

Current Concepts and Best Evidence on Strategies to Prevent Dental Erosion.

Dental erosion is a multifactorial condition associated with chemical, biological, and behavioral factors whereby a non-bacterial chemical process leads to an irreversible loss of dental structure. Consequences of this erosive process include painful sensitivity, susceptibility to further erosion, mechanical wear, changes in occlusion, exposure of dental pulp, and poor esthetics. Substantial evidence has revealed new insights to diagnosing early stages of dental erosion and enabling novel preventive approaches to control its progression. In the context of outpatient medical/dental practice, clinicians often encounter patients with progressive dental erosion. This article summarizes published research in this area of dentistry to suggest guidelines that are clinically oriented but scientifically fundamental. It is aimed at helping clinicians effectively integrate this information into their professional evaluations of dental erosion with regard to diagnosis, risk factors, clinical signs, assessment, and clinical preventive strategies and treatment. Clinicians should address patient diet habits, educate patients on prevalence data, and inform them regarding potential acidic interactions, such as medically induced acidic conditions, that may ultimately lead to tooth destruction. Prevention of dental erosion, including the recognition of initial erosive lesions and the implementation of the early intervention, involves the clinical expertise of both the dentist and physician.

Factors influencing success of radiant exposure in light-curing posterior dental composite in the clinical setting.

PURPOSE: (1) To conduct a comprehensive review of the literature on factors influencing the radiant exposure of resin-based composite (RBC) restorations and (2) To fully understand the appropriate way of using the light curing units (LCUs) to perform restorations with optimal mechanical/physical properties. METHODS: A PubMed search identified recent publications in English that addressed the factors affecting the longevity of the RBC restorations and the optimal usage of LCUs. RESULTS: RBCs require light-induced polymerization of methacrylate monomers present in its composition to reach acceptable mechanical and physical properties. Complete polymerization of the RBC is never reached, and the maximum degree of conversion (DC) varies from 40 to 80%. The amount of radiant exposure (Joules/cm²) required for the commencement of polymerization becomes a core driver for the quality of the RBCs. Insufficient radiant exposure may lead to low strength behavior and susceptibility to degradation, thereby shortening the lifespan of restorations inside the mouth. This suggests that there are factors affecting the radiant exposure during clinical procedures; these factors can be categorized as material-related, LCU-related and operator-related factors. CLINICAL SIGNIFICANCE: Proper light-curing techniques are critical for delivering an adequate amount of radiant exposure to RBCs. Adequate light curing decreases the number of underexposed RBC restorations, improves their mechanical and physical properties and accordingly, increases their clinical longevity.

Effect of instruction, light curing unit, and location in the mouth on the energy delivered to simulated restorations.

PURPOSE: To determine the amount of energy (Joules/cm²) delivered by students to simulated restorations in a patient simulator based on the restoration location, the curing light unit used, and before vs. after instruction on how to improve their light curing technique. METHODS: 30 dental students "light cured" two simulated restorations (that were 1-mm deep anterior and 4-mm deep posterior) using three light-curing units (LCUs) : VALO, Bluephase G2, and Optilux 401. A MARC Patient Simulator was used to measure the irradiance (mW/cm²) received by the restorations in real-time to calculate the radiant exposure (J/cm²) delivered during a 20-second exposure. At first, students were asked to use the light curing technique that they had been previously taught. They were then given 5 minutes of additional verbal instructions and a practical demonstration on proper curing technique using the patient simulator. They then light cured the restorations again. Based on a literature review, 16 J/cm² was considered the minimum acceptable radiant exposure. RESULTS: Before receiving instruction using the simulator, some students delivered as little as 4 J/cm² to the restoration. A mixed model test determined that the radiant exposure delivered to the anterior restoration was significantly greater than that delivered to the posterior restoration (Plt; 0.001). Additionally, when the locations were compared for each LCU individually, a paired t-test determined that before the students received the additional instruction, the anterior restoration received a significantly greater radiant exposure than the posterior restoration, for all three LCUs. Further paired t-tests and Wilcoxon signed-rank tests determined that after instruction, the radiant exposure improved significantly at both the anterior and posterior locations, for all three LCUs. The Bluephase G2 and the VALO each individually delivered 45% more radiant exposure than the Optilux 401 (P< 0.001 for both). The Bluephase G2 and VALO lights delivered similar mean radiant exposures (25.4 J/cm² and 25.7 J/cm², respectively). This difference was not significant. Depending on the light unit used, at the posterior location, there was a 24 to a 52% increase in the mean radiant exposure that was delivered after instruction compared to before instruction. CLINICAL SIGNIFICANCE: Prior to using the patient simulator, students and their instructors thought that the students were delivering an adequate amount of energy when light curing. This was not always the case. The location of the restoration, the curing light output, its size and shape and how it is used all affected the amount of energy delivered to a restoration. Dental professionals and educators should be aware that appropriate training can improve the amount of energy delivered, and that restorations in posterior teeth will require longer exposure times than those in anterior teeth.

The dental curing light: A potential health risk.

Powerful blue-light emitting dental curing lights are used in dental offices to photocure resins in the mouth. In addition, many dental personnel use magnification loupes. This study measured the effect of magnification loupes on the "blue light hazard" when the light from a dental curing light was reflected off a human tooth. Loupes with 3.5x magnification (Design for Vision, Carl Zeiss, and Quality Aspirator) and 2.5x magnification (Design for Vision and Quality Aspirator) were placed at the entrance of an integrating sphere connected to a spectrometer (USB 4000, Ocean Optics). A model with human teeth was placed 40 cm away and in line with this sphere. The light guide tip of a broad-spectrum Sapphire Plus (Den-Mat) curing light was positioned at a 45° angle from the facial surface of the central incisor. The spectral radiant power reflected from the teeth was recorded five times with the loupes over the entrance into the sphere. The maximum permissible cumulative exposure times in an 8-hr day were calculated using guidelines set by the ACGIH. It was concluded that at a 40 cm distance, the maximum permissible cumulative daily exposure time to light reflected from the tooth was approximately 11 min without loupes. The weighted blue irradiance values were significantly different for each brand of loupe (Fisher's PLSD p < 0.05) and were up to eight times greater at the pupil than when loupes were not used. However, since the linear dimensions of the resulting images would be 2.5 to 3.5x larger on the retina, the image area was increased by the square of the magnification and the effective blue light hazard was reduced compared to without the loupes. Thus, although using magnification loupes increased the irradiance received at the pupil, the maximum cumulative daily exposure time to reflected light was increased up to 28 min. Further studies are required to determine the ocular hazards of a focused stare when using magnification loupes and the effects of other curing lights used in the dental office.

Effects of water-aging on self-healing dental composite containing microcapsules.

OBJECTIVES: The objectives of this study were to develop a self-healing dental composite containing poly(urea-formaldehyde) (PUF) shells with triethylene glycol dimethacrylate (TEGDMA) and N,N-dihydroxyethyl-p-toluidine (DHEPT) as healing liquid, and to investigate the mechanical properties of the composite and its self-healing efficacy after water-aging for 6 months. METHODS: PUF microspheres were synthesized encapsulating a TEGDMA-DHEPT healing liquid. Composite containing 30% of a resin matrix and 70% of glass fillers by mass was incorporated with 0%, 2.5%, 5%, 7.5% and 10% of microcapsules. A flexural test was used to measure flexural strength and elastic modulus. A single edge V-notched beam method was used to measure fracture toughness (KIC) and self-healing efficacy. Specimens were water-aged at 37 °C for 1 day to 6 months and then tested for self-healing. Fractured specimens were healed while being immersed in water to examine self-healing efficacy, in comparison with that in air. RESULTS: Incorporation of up to 7.5% of microcapsules into the resin composite achieved effective self-healing, without adverse effects on the virgin mechanical properties of the composite (p>0.1). An excellent self-healing efficacy of 64-77% recovery was obtained (mean±sd; n=6). Six months of water-aging did not decrease the self-healing efficacy compared to 1 day (p>0.1). Exposure to water did not decrease the healing efficacy, compared to that healed in air (p>0.1). CONCLUSIONS: A composite was developed with excellent self-healing efficacy even while being immersed in water. The self-healing efficacy did not decrease with increasing water-aging time for 6 months. CLINICAL SIGNIFICANCE: The novel self-healing composite may be promising for dental applications to heal cracks, resist fracture, and increase the durability and longevity.

Using fiber-optic transillumination as a diagnostic aid in dental practice.

Fiber-optic transillumination (FOTI) is a well-accepted and valuable adjunctive diagnostic tool with a wide range of clinical applications. In dentistry, FOTI has been primarily associated with caries diagnosis and has been corroborated through research studies to be a valid indicator of the histological presence or absence of bacterially infected tooth structure. In this review, techniques for using FOTI for tooth evaluation are presented along with examples of how FOTI can be effectively used as a supplemental diagnostic aid.

The effectiveness of using a patient simulator to teach light-curing skills.

BACKGROUND: The authors evaluated the effectiveness of using a patient simulator (MARC Patient Simulator [MARC PS], BlueLight analytics, Halifax, Nova Scotia, Canada), to instruct dental students (DS) on how to deliver energy optimally to a restoration from a curing light. Five months later, the authors evaluated the retention of the instruction provided to the DS. METHODS: Toward the end of the DS' first year of dental education, the authors evaluated the light-curing techniques of one-half of the class of first-year DS (Group 1) before and after receiving instruction by means of the patient simulator. Five months later, they retested DS in Group 1 and tested the remaining first-year DS who were then second-year DS and who had received no instruction by means of the patient simulator (Group 2). They gave DS in Group 1 and Group 2 MARC PS instruction and retested them. The authors also the tested fourth-year DS (Group 3) and dentists (Group 4) by using the MARC PS before giving any instruction by means of the MARC PS. RESULTS: The results of one-way analysis of variance (ANOVA) showed that there were no significant differences in the ability of dentists and DS to light cure a simulated restoration before they received instruction by means of the patient simulator (P = .26). The results of two-way ANOVA and Fisher protected least significant difference tests showed that after receiving instruction by means of the patient simulator, DS delivered significantly more energy to a simulated restoration, and this skill was retained. There were no significant differences between DS in Group 1 and Group 2 after they had received instruction by means of the patient simulator. CONCLUSIONS: The abilities of dentists and DS to light cure a simulated restoration were not significantly different. Hands-on teaching using a patient simulator enhanced the ability of DS to use a curing light. This skill was retained for at least five months. PRACTICAL IMPLICATIONS: The education provided to dentists and DS is insufficient to teach them how to deliver the optimum amount of energy from a curing light. Better teaching and understanding of the importance of light curing is required.

Fixed prosthodontics provisional materials: making the right selection.

Clinicians have many choices when selecting an appropriate material for interim restorations for both single crowns and multi-units. Interim restorations serve as a diagnostic as well as biologic and biomechanical component of fixed prosthodontics treatment; in the anterior, they are also important in evaluating the esthetics for the definitive restoration. Factors to be considered when choosing provisional materials are physical properties, handling characteristics, patient response to the appearance of the interim restoration, durability of the restoration, and the cost of the material. Practitioners should, therefore, base their choice on the clinical needs for each situation.

Nanocomposite containing CaF(2) nanoparticles: thermal cycling, wear and long-term water-aging.

OBJECTIVES: Fluoride (F) releasing dental restoratives are promising to promote remineralization and combat caries. The objectives of this study were to develop nanocomposite containing calcium fluoride nanoparticles (nCaF(2)), and to investigate the long-term mechanical durability including wear, thermal-cycling and long-term water-aging behavior. METHODS: Two types of fillers were used: nCaF(2) with a diameter of 53 nm, and glass particles of 1.4 µm. Four composites were fabricated with fillers of: (1) 0% nCaF(2)+65% glass; (2) 10% nCaF(2)+55% glass; (3) 20% nCaF(2)+45% glass; (4) 30% nCaF(2)+35% glass. Three commercial materials were also tested. Specimens were subjected to thermal-cycling between 5°C and 60°C for 10(5) cycles, three-body wear for 4×10(5) cycles, and water-aging for 2 years. RESULTS: After thermal-cycling, the nCaF(2) nanocomposites had flexural strengths in the range of 100-150 MPa, five times higher than the 20-30 MPa for resin-modified glass ionomer (RMGI). The wear scar depth showed an increasing trend with increasing nCaF(2) filler level. Wear of nCaF(2) nanocomposites was within the range of wear for commercial controls. Water-aging decreased the strength of all materials. At 2 years, flexural strength was 94 MPa for nanocomposite with 10% nCaF(2), 60 MPa with 20% nCaF(2), and 48 MPa with 30% nCaF(2). They are 3-6 fold higher than the 15 MPa for RMGI (p<0.05). SEM revealed air bubbles and cracks in a RMGI, while composite control and nCaF(2) nanocomposites appeared dense and solid. SIGNIFICANCE: Combining nCaF(2) with glass particles yielded nanocomposites with long-term mechanical properties that were comparable to those of a commercial composite with little F release, and much better than those of RMGI controls. These strong long-term properties, together with their F release being comparable to RMGI as previously reported, indicate that the nCaF(2) nanocomposites are promising for load-bearing and caries-inhibiting restorations.