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The authors conducted a study to determine the validity of two commercially available in-office dental unit waterline test kits compared to the gold standard, R2A agar. Samples were collected from the air/water syringes of dental units and cultured on HPC Samplers, Petrifilm AC Plates, and R2A agar plates. HPC Samplers and R2A agar plates were incubated for 7 days and counted manually using magnification. Petrifilm AC Plates were counted after incubation time of 5 and 7 days using an electronic-plate reader. Validity measurements were calculated using a cutoff value < or = 500 colony-forming units per milliliter. The accuracy for the HPC Sampler compared to R2A agar was 71%. The accuracy for the Petrifilm AC Plates at 5 and 7 days was 79% and 87% compared to R2A agar. The Petrifilm AC Plate (7-day incubation) demonstrated higher sensitivity, specificity, predictive values, and accuracy than the HPC Sampler kit. [ABSTRACT FROM AUTHOR]

This study sought to determine how irradiance at various distances affected the hardness of a new silorane-based composite compared to a methacrylate-based composite resin restorative material. A visible-light curing unit was used at low and high irradiances. Plastic molds of various thicknesses (1, 2, 3, and 4 mm) were filled with composite resin and polymerized for 20 seconds at various distances (0, 2, 4, and 6 mm). After 24 hours of storage at 37°C, the microhardness of each specimen was tested at the bottom surface using a microhardness tester. These microhardness values were expressed as a percentage of maximum microhardness and analyzed with ANOVA and Tukey's post-hoc tests. At both low and high irradiances, the silorane-based composite (shade A2) was capable of acceptable (80%) bottom-to-maximum microhardness ratios at increments up to 3 mm and at curing distances up to 4 mm (at low irradiance) and 6 mm (at high irradiance). [ABSTRACT FROM AUTHOR]

Manufacturers often recommend refrigerated storage of self-etching enamel and dentin adhesives. The purpose of this study was to compare the shear-bond strength of composite resin to dentin using two different self-etching adhesives after extended storage at room or refrigerated temperatures. One- and two-step self-etching bonding agents were stored separately at room (23 degrees C) or refrigerated temperatures (5 degrees C) per manufacturer recommendations for 1, 4, or 18 months before testing. After each time period, composite resin was bonded to the dentinal surface of extracted human third molars using a mold and tested in shear on a universal-testing machine. Data were analyzed with analysis of variance/Tukey's test. No significant difference in bond strengths was found on the basis of storage temperature for either adhesive type. The one-step adhesive had a significant loss in bond strength over the 18 months of storage. However, the two-step self-etch adhesive had no loss in bond strength, regardless of storage temperature. [ABSTRACT FROM AUTHOR]

Objective: The goal was to evaluate the effect of high-heat storage of three dental adhesive bonding agents on the bond strength of composite resin to dentin.Methods: Three different adhesive bonding agents were stored for 1 month at the manufacturers' recommended temperatures and simultaneously at high temperatures (43 degrees C). The adhesives and a composite resin restorative material were bonded to the dentinal surface of five sectioned, extracted, human teeth for each of the six groups. The teeth were further sectioned into four beams per tooth (N=20) and separated with a universal testing machine. Data were analyzed with analysis of variance/Tukey's test and Student's t test.Results: One of the three bonding agents had significantly lower bond strength when stored in a high-heat environment (p = 0.0003).Conclusions: High-heat storage conditions, as may occur in areas of deployment in Southwest Asia, may cause a reduction in the performance of some dental adhesives, potentially leading to premature failure of the restoration. [ABSTRACT FROM AUTHOR]

This study sought to determine how repeated applications of a refrigerant spray on various cotton carriers affected the change in pulpal temperature. A thermocouple was placed at the roof of the pulp chamber of a human maxillary canine and connected to a thermometer logging at one-second intervals while the root was immersed in a water bath at 37 degrees C. Four different carrier types were used: large cotton pellets, small cotton pellets, cotton-tip applicators, and cotton rolls. Each carrier was sprayed with 1,1,1,2-tetrafluoroethane and placed on the crown for five seconds. Pulpal temperature change was recorded after each five second application of the same carrier to the tooth until a total of six consecutive sprays and applications of the carrier were applied. Each carrier group consisted of 10 performances of the six sets of readings (n = 10). The difference between baseline and the low temperature reading was calculated to determine the temperature change (in degrees C) in the pulp chamber per application. When the refrigerant spray was used, the large cotton pellet carrier generally produced the largest decrease in pulpal temperature at each repeated application compared to the other types of carriers. However, the same large cotton pellet should not be sprayed with the refrigerant more than two times before it is replaced. [ABSTRACT FROM AUTHOR]

Introduction: Teledentistry, also known as "virtual" dental examinations, is an innovative approach to increasing access to care. The objective of this study was to evaluate the diagnostic inter-rater reliability between virtual and in-person examinations for patients seeking emergency dental care (sick call) at a military dental treatment facility., Materials and Methods: One hundred subjects received both virtual and in-person examinations on the same day, in random order. The virtual examiner and subject were stationed in separate rooms and used only a laptop equipped with a camera, microphone, and speaker to complete the virtual exam. In contrast, the in-person examiner had access to all standard care modalities in a dental treatment room. After the first encounter, the subject proceeded to the corresponding virtual or in-person exam, and both examiners determined a diagnosis. Inter-rater agreement was determined between the two encounters for both diagnosis specialty category and diagnostic code using the Kappa coefficient., Results: The results of the inter-rater analyses showed a Kappa score of 0.644 for the diagnosis specialty category (P < .001) and a Kappa score of 0.714 for diagnostic codes (P < .001). Both analyses indicated "substantial" agreement., Conclusions: We conclude that teledentistry can be an effective tool for determining a diagnosis and improving access to care for dental emergencies at military dental treatment facilities., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2024. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: A core objective of U.S. medical services is to ensure the medical and dental readiness of military personnel. Oral diseases, resulting in pain, infection, or functional impairment, greatly affect the operational effectiveness of military personnel. This study aimed to compare the current causes of dental emergencies and the rates of dental disease nonbattle injuries in a deployed setting with those documented in previous research. Additionally, the study sought to determine if these rates have decreased because of preventive measures or potential improvements in overall oral health., Methods: Each soldier reporting to the health facility for dental care was screened by a dentist to determine the presence of a dental emergency. The reason for seeking care was classified into 1 of 7 categories and the rate of dental emergencies per 1,000 military members per calendar year was calculated., Results: The majority of emergencies (38.60%) were due to tooth fractures and/or caries. The second most common reason for visiting the dental clinic was pain from a tooth requiring endodontic therapy (16.81%). This was followed by musculoskeletal or nonendodontic tooth pain (16.10%), most often associated with stress. Periodontal issues accounted for 14.33% of emergencies. Teeth requiring extraction made up 7.16% of all emergencies, prosthodontic bonding complications accounted for 5.16%, and orthodontic bonding complications affected 1.84% of individuals. The dental disease nonbattle injuries rates determined from the current study were 154 emergencies per 1,000 personnel per year for Air Force members and 264 emergencies per 1,000 personnel per year for Army members, which align with previous research findings., Conclusions: The results of this study confirm that dental emergencies continue to be a threat to overall readiness in deployed environments. The primary etiologic factor in the current study was as a result of tooth fracture and/or caries., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2024. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: The Air Force Dental Service is responsible for ensuring that airmen are dentally ready to support military operations worldwide by delivering top-tier dental care. As the military healthcare landscape undergoes significant changes, the Air Force Dental Service has explored innovative approaches to dental care delivery. One consideration involves the potential use of radiographs as the primary tool for assessing service members' dental conditions, specifically focusing on identifying nondeployable conditions and periodontal health., Materials and Methods: Providers who previously participated as examiners in the 2018 Air Force Recruit Oral Health Study were recruited to re-evaluate randomly selected de-identified records, this time making assessments exclusively based on radiographs. Their evaluations included Dental Readiness Classification (DRC) determinations, total caries counts, and Periodontal Screening and Recording (PSR) index scores, providers also rated their confidence in these conclusions using a 5-point Likert scale. The study then computed sensitivity and specificity to assess the diagnostic performance of providers using radiographs only compared to the original study results that use the gold standard of radiographs with a clinical examination., Results: Providers exceled at ruling out most DRC 3 conditions, with specificities surpassing 70%. Positively identifying those with DRC 3, particularly radiographically identifying periodontal conditions posed challenges with computed sensitivity rates as low as 8%. Discrepancies in PSR scores also accentuated limitations in relying solely on radiographs, where provider's radiographically determined PSR scores that matched less than one third of the time. In general, providers had low to very low confidence in their assessments., Conclusions: The study strongly cautions against relying solely on radiographs for determining the dental health of U.S. Air Force personnel. While providers effectively ruled out the absence of certain conditions, the challenge of positively identifying DRC 3 conditions poses significant risks to oral health if such a workflow was utilized. Particularly, the high probability of false negatives would be detrimental to the operational readiness of military personnel. Therefore, results support the continued use of radiographic and clinical examinations for comprehensive dental exams., (© The Association of Military Surgeons of the United States 2024. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site–for further information please contact journals.permissions@oup.com.)

Limited research is available evaluating whether the reported in vitro benefit of immediate dentin sealing (IDS)-namely, increased bond strength to tooth structure-can be acquired in the era of same-day (SD) dentistry. The purpose of this study was to compare the fracture strengths of ceramic overlays fabricated with a delayed dentin sealing (DDS) technique or an IDS technique under 1-hour SD or 2-week multiple-day (MD) delivery conditions. Forty extracted, healthy maxillary third molars were prepared for a lithium disilicate overlay restoration and divided into 4 groups of 10 teeth each. In the SD-DDS group, the teeth were prepared and then stored for 1 hour in artificial saliva, and the adhesion protocol (bonding agent and resin cement) was applied at the time of delivery of the ceramic overlay. In the SD-IDS group, the teeth were prepared, the adhesive protocol was applied immediately, and the teeth were stored for 1 hour before delivery of the overlay. The protocols for the MD-DDS and MD-IDS groups were identical to SD-DDS and SD-IDS, respectively, except that the teeth were provisionalized and stored for 2 weeks prior to delivery of the overlay. Specimens were thermocycled and subjected to cyclic functional loading before they were loaded to failure in a universal testing machine using a rod resting on the buccal incline of the palatal cusp. Two-way analysis of variance tests revealed no statistically significant differences in fracture strength between the groups based on dentin sealing (P = 0.331) or delivery time (P = 0.314). The specimens demonstrated 2 fracture types; either a portion of the ceramic cohesively fractured, leaving the tooth intact, or the ceramic and part of the tooth fractured. There were no instances in which the restoration itself delaminated during fracture testing. A Kruskal-Wallis test indicated there were no statistically significant differences in fracture modes between the groups. In this in vitro study, IDS did not provide a significant increase in the fracture strength of overlay restorations compared with DDS, regardless of whether the restorations were delivered the same day or after 2 weeks of storage., Competing Interests: No conflicts of interest reported.

Aim: This study aimed to evaluate the marginal microleakage and maximum occlusal fracture loads and fracture modes of two novel class II preparation designs, "infinity edge" and the "2.5 mm cusp reduction" preparations as compared to a traditional class II preparation without cuspal involvement., Materials and Methods: Thirty extracted human mandibular molars were prepared for moderate-sized class II restorations with extensions into all occlusal grooves. Of these, ten class II preparations served as control. Ten were modified for a 2.5 mm even reduction of the cusps adjacent to the interproximal box. An additional 10 preparations were modified with an "infinity edge" bevel on the interproximal and occlusal portions. All teeth were restored utilizing a flowable bulk-fill composite in the apical portion of the interproximal box and 2-4 mm of heated bulk-fill composite in one increment for the remainder. All groups were cyclic loaded and thermocycled, then imaged with microcomputed tomography (µCT) before and after infiltration with a silver nitrate solution. Images were subtracted to obtain volumetric measurements of microleakage and reported as a percentage of the total volume from the apical extent of the proximal box. All groups were loaded to failure and fracture load and mode were recorded., Results: No significant differences were found in microleakage volume as a percentage of total tooth volume; however, the "infinity edge" group had significantly greater microleakage in the proximal box compared to the traditional class II group. No significant differences were found in fracture load or mode between the groups., Conclusion: Traditional class II, 2.5 mm cuspal reduction, and "infinity edge" preparation designs have similar fracture loads as well as volumes of microleakage; however, an "infinity edge" preparation has a higher ratio of microleakage in the proximal box., Clinical Significance: Clinicians should carefully consider the use of "infinity edge" margins, particularly on dentin in the apical extent of the proximal box. How to cite this article: Watson JC, Lien W, Raimondi JC, et al . In Vitro Microleakage and Fracture Resistance of "Infinity Edge" and Cusp Reduction Preparation Designs for Moderate-sized Class II Composites. J Contemp Dent Pract 2024;25(1):3-9.

Background: The purpose of this study was to evaluate the effect of milling speed on the surface roughness, marginal gap, marginal gap volume, marginal offset, and fracture load of zirconia restorations., Material and Methods: A mandibular molar #30 typodont tooth was digitally scanned and an ideal crown preparation for a zirconia restoration was digitally created. A single master model die of the crown preparation was milled out of a resin material. The master die was scanned, and a final restoration was designed using the bio-copy feature of the typodont tooth. Ten zirconia restorations were milled (CEREC Primemill, Dentsply Sirona) per each of three milling speeds (super-fast, fine, and extra-fine), sintered, and seated on the master die. Surface roughness, marginal gap, marginal gap volume, and marginal offset were measured using a non-contact profilometer. Then, all restorations were cemented to the dies and loaded to failure in a material testing device. Data were analyzed with one-way ANOVA and Tukey's post hoc tests per property (alpha=0.05)., Results: Super-fast milling speed resulted in restorations with statistically significant greater surface roughness and marginal gap volume compared to fine and extra-fine milling speeds. No significant difference in marginal gap, marginal offset, and fracture load were found based on milling speed., Conclusions: Zirconia restorations milled at slower speeds may result in similar or slightly better properties compared to super-fast speed. Key words: Milling speed, properties, zirconia restorations., Competing Interests: Conflicts of interest The authors do not have any financial interest in the companies whose materials are discussed in this manuscript., (Copyright: © 2024 Medicina Oral S.L.)

Aim: The purpose of this study was to evaluate the bond strength and fracture mode of universal resin cement to dentin compared to self-adhesive and adhesive resin cement with and without an adhesive bonding agent., Materials and Methods: Seventy-two molar teeth were sectioned to expose coronal dentin, divided into three groups, and assigned to RelyX Universal (universal), RelyX Ultimate (adhesive), or RelyX Unicem 2 (self-adhesive) cements from 3M. The 3 groups were further subdivided into 2 subgroups of 12 specimens each, with or without the use of an adhesive bonding agent. Lithium-disilicate discs were bonded to the dentin surface using the cements, stored for 24 hours in distilled water, and subjected to 2,000 thermocycles before shear bond strength testing and fracture mode analysis., Results: Significant differences in bond strength and fracture mode were found between groups based on cement or the use of a bonding agent. Both the universal and adhesive cements had significantly greater bond strengths to dentin with the use of a bonding agent versus no bonding agent. With the self-adhesive cement, there was no significant increase in bond strength to dentin with the use of a bonding agent., Conclusion: The novel universal resin cement had similar bond strengths to dentin as the adhesive cement with the use of a bonding agent, and similar bond strengths as the self-adhesive cement without the use of a bonding agent. The adhesively bonded universal cement had the greatest percentage of mixed and cohesive fractures., Clinical Significance: When greater adhesion is needed clinically, the novel universal resin cement may be used with an adhesive bonding agent. However, when less adhesion is needed, it could be used without a bonding agent in self-adhesive mode.

Objective: The purpose of this study was to compare the optical and mechanical properties of newer ceramic CAD/CAM materials to more established materials on the market., Methods and Materials: The following ceramic materials were tested: lithium disilicate/lithium-aluminum silicate (Tessera, Dentsply/Sirona), lithium disilicate (Initial LiSi Block, GC), IPS e.max CAD, Ivoclar Vivadent), and 4Y polycrystalline stabilized zirconia (IPS e.max ZirCAD MT, Ivoclar Vivadent; Katana STML, Kuraray; YZ ST, VITA). Optical properties (translucency, opalescence) were determined using a dental spectrophotometer on 0.5-, 1.0-, 1.5-, or 2.0-mm specimens. Mechanical properties (flexural strength, flexural modulus, flexural fatigue strength, Weibull modulus, and characteristic strength) were determined with beams undergoing 3-point bend testing. The data were analyzed with multiple analyses of variance and Tukey's post hoc tests (α=0.05)., Results: Significant differences were found between groups based on type of ceramic or property (p<0.05)., Conclusions: In general, the lithium disilicate based-ceramic materials had greater optical properties and lower mechanical properties than the zirconia-based ceramic materials., (©Operative Dentistry, 2023.)

The purpose of this study was to evaluate the accuracy of an intraoral scanner based on camera sleeve type, decontamination protocol, and calibration status. Five extracted human teeth were set into a gypsum stone model and prepared for various indirect restorations. An optical impression was completed with a benchtop scanner to serve as a reference standard. A total of 160 optical impressions were completed using a sterilizable sleeve, an autoclavable sleeve with a single-use plastic window, or a single-use disposable plastic sleeve attached to a calibrated or an uncalibrated intraoral scanner. For the sterilizable sleeves, 2 decontamination protocols were used--high-level disinfection (HLD) or dry heat sterilization (DHS)--and scans were performed at baseline and after 25 and 50 cycles for each protocol. For the autoclavable (AS) and disposable single-use (SU) sleeves, scans were performed at baseline only. Thus, there were 10 optical impressions per test condition: sleeve type (HLD, DHS, AS, or SU) × decontamination status (baseline, 25 cycles [HLD or DHS], or 50 cycles [HLD or DHS]) × calibration status (calibrated or uncalibrated scanner). The individual optical impressions were compared to the reference standard impression by using 3-dimensional best-fit superimposition with the prepared tooth surfaces as reference points, and 3-dimensional linear differences were calculated for each superimposition. The median positive and absolute value median negative distance measurements were averaged for each impression to generate an average median discrepancy from baseline. The data were analyzed with Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). No statistically significant differences in the median linear distance were found, regardless of sleeve type, decontamination protocol, or calibration status (P > 0.05). All groups demonstrated statistically similar linear disparities, ranging from 11.78 to 14.00 μm. The most precise sleeves were the single-use plastic sleeves, although their results were not significantly different from those of the multiuse sleeve. The results indicated that any of the currently available camera sleeves can provide similar accuracy in a clinical setting and that single-use disposable sleeves are a viable alternative to the currently accepted multiuse sleeves., Competing Interests: No conflicts of interest reported.

The dental setting is regarded as a high-risk environment for aerosol concentrations and transmission of respiratory infectious agents, especially in relation to the COVID-19 pandemic. Although a number of approaches and practices have evolved to reduce the spread of pathogens in the dental setting, the risk of airborne infection remains a concern. Several new extraoral suction (EOS) devices have been marketed recently; further investigation is warranted to determine their clinical effectiveness. The aim of this study was to evaluate the efficacy of a chairside EOS device (PAX 2000 Extraoral Dental Suction System) in reducing aerosol contamination from patients receiving ultrasonic scaling by a registered hygienist as a part of initial or supportive periodontal therapy. The number of colony-forming units (CFUs) was measured with agar plates before, during, and after ultrasonic scaling at 3 different locations in the dental operatory (instrument table, patient chest area, and patient foot area). Forty subjects were randomly allocated into 2 test groups (n = 20) in which ultrasonic scaling was performed with or without the use of the EOS device. The CFUs retrieved after incubation were quantified and identified by their bacterial or fungal taxon. The use of the EOS device reduced the number of CFUs during scaling at all 3 locations, but the difference was only statistically significant (P = 0.018; Mann-Whitney U test) at the patient's chest area, where the highest number of CFUs was present. The aerosols consisted of 74 different taxa of human origin. The results suggest that the tested EOS system may reduce aerosol contamination in the clinical dental setting, especially in proximity to the patient's head, where most aerosols are generated., Competing Interests: No conflicts of interest reported.

The purpose of this study was to compare the performances of 5 different instruments in measuring the irradiance of light-curing units (LCUs). A novel spectrometer-trained radiometer (CheckUp), 2 conventional chairside radiometers (Bluephase Meter I and Bluephase Meter II), and 2 devices considered to be gold standards for measuring irradiance (an integrating sphere spectrometer and a thermopile sensor) were used to evaluate 7 LCUs. The irradiance of each LCU was measured 10 times with each meter. Data were analyzed using linear regression analysis and a 1-way analysis of variance with Tukey post hoc test (α = 0.05). The mean irradiance values of the LCUs differed significantly depending on which meter was used for measurement (P < 0.05). Bivariate regression analysis demonstrated that the highest correlations in the irradiance values were found between the CheckUp meter and both the integrating sphere (r 2 = 0.980) and the thermopile (r 2 = 0.933). The absolute mean (SD) percentage deviation between irradiance measured by the CheckUp instrument and irradiance measured by the other meters was 7.2% (2.0%) for the integrating sphere, 7.0% (3.6%) for the thermopile, 21.5% (16.1%) for Bluephase Meter I, and 13.1% (7.1%) for Bluephase Meter II. Compared with the 2 conventional chairside radiometers, the CheckUp meter provided the highest correlation with and lowest absolute percentage deviation from the irradiance measured by the gold standard spectrometers., Competing Interests: No conflicts of interest reported.

While evidence shows that dental erosion (DE) is often caused by gastroesophageal reflux disease (GERD), the relationship of DE severity to a patient's symptoms and receipt of appropriate medical treatment for GERD is not clearly understood. The purpose of this study was to evaluate the association between DE and GERD. Eighty participants underwent a Basic Erosive Wear Examination for DE and completed the Patient-Reported Outcomes Measurement Information System (PROMIS) survey on symptoms of gastrointestinal reflux (PROMIS Scale v1.0, Gastrointestinal Gastroesophageal Reflux 13a) in English. Patients with observed erosive patterns were referred for gastroenterologic evaluation. The association between DE and GERD was assessed using multiple regression. The results showed that the extent of DE was positively associated with GERD symptoms (B = 0.585; 95% CI, 0.21-0.96), as measured by the PROMIS survey, in participants without a current diagnosis of GERD. Of the 80 patients in the study, 28 with more severe DE were evaluated in the gastroenterology department. A diagnosis of GERD was established for 27 of the 28, 9 of whom denied a past history of the disease. Twenty patients with GERD underwent upper endoscopy, and esophageal lesions were found in 6 patients (erosive esophagitis in 5 and Barrett esophagus in 1). Patients with clinically identified DE may benefit from medical evaluation and, if necessary, management of GERD. For a subset of patients, DE may be the only clinical indication of untreated or undertreated GERD, which could lead to serious esophageal changes. Dentists should consider referring patients with DE to primary care providers or gastrointestinal specialists to ensure that systemic conditions are identified and managed appropriately., Competing Interests: The views expressed are those of the authors and do not reflect the official views or policy of the Uniformed Services University, US Department of Defense, or its components. The authors do not have any financial interest in any companies discussed in this manuscript.

Background: This study investigated the properties (depth of cure, surface hardness, and volumetric shrinkage) of two composite restorative materials when polymerized with a novel "quad" spectrum (PinkWave) light-curing unit (LCU) compared to a tri-spectrum LCU (Valo Grand)., Material and Methods: One Valo Grand LCU was modified to be similar in irradiance to the PinkWave, and a second Valo Grand was utilized at the manufacturer's standard irradiant settings. Depth of cure was evaluated using the scraping technique (ISO 4049). Top and bottom surface hardness and bottom/maximum hardness ratios were determined using a hardness tester. Volumetric shrinkage was determined using a video-imaging device. Additionally, the surface temperature of the light tips of the LCUs was measured using a K-type thermocouple., Results: No significant difference in depth of cure was found with either composite between the PinkWave LCU and the modified Valo Grand LCU at similar irradiance. The unadjusted Valo Grand LCU had slightly less depth of cure. There was no difference in top or bottom surface hardness, bottom/maximum hardness ratios, or volumetric shrinkage between any of the LCU curing modes per composite type. The PinkWave LCU had a significantly greater increase in heat at the tip compared to the modified Valo Grand LCU at similar irradiance and the unadjusted Valo Grand LCU., Conclusions: The new quad-spectrum LCU, PinkWave, had a significant increase in surface temperature without any improvement in the composite properties tested compared to the tri-spectrum LCU, Valo Grand, at similar irradiance. Key words: Light-curing unit, emission spectrum, composite resin, mechanical and physical properties., Competing Interests: Conflicts of interest None declared., (Copyright: © 2022 Medicina Oral S.L.)

Limited research has been published evaluating the failure of zirconia crowns with less retentive tooth preparations. The purpose of this study was to evaluate the effect of axial wall height (AWH) and cement type on the fracture load of cubic phase-containing zirconia crowns. Standardized crown preparations with an AWH of 0, 2, or 4 mm (n = 10) were made in 90 extracted human maxillary third molars. The preparations were scanned, and crown restorations were designed. Cubic phase-containing zirconia crowns were milled and cemented with a resin-modified glass ionomer cement, a self-adhesive resin cement, or an adhesive resin cement. The specimens were subjected to thermocycling and cyclic loading. Each crown specimen was positioned in a universal testing machine so that the long axis of the tooth was at a 60° angle to the testing fixture and loaded until failure using a stainless steel rod resting on the buccal incline of the palatal cusp. Data were found to have a nonnormal distribution and were analyzed with Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). Statistically significant differences in the median fracture loads of the groups were found based on both AWH and cement type (P < 0.05). Regardless of cement type, the median fracture loads were significantly lower in the 0-mm AWH groups than in the 2-mm and 4-mm AWH groups, which were not significantly different from each other. Compared to the other cement types, adhesive resin cement resulted in a significantly greater median fracture load when the AWH was 0 mm. The use of an adhesive resin cement with a cubic phase-containing zirconia crown may provide greater fracture resistance for preparations with minimal AWH., Competing Interests: The views expressed are those of the authors and do not reflect the official views or policy of the Uniformed Services University, US Department of Defense, or its components. The authors do not have any financial interest in the companies whose materials are discussed in this manuscript.

The objective of this study was to evaluate the efficacy of various decontamination methods and subsequent sterilization on contaminated and inoculated diamond-coated burs. One hundred forty new diamond-coated burs and 120 extracted human molars were utilized in this study. The burs were divided into 7 groups (n = 20): 1, positive control; 2, negative control; 3, new, unused burs; and 4 to 7, burs subjected to various combinations of cleaning methods (manual cleaning, use of a cleaning stone, and/or ultrasonic cleaning) after contamination. In all of the groups except group 3, the burs were sterilized and used to abrade the enamel and dentin of the sterilized extracted teeth. In groups 1 and 4 to 7, the burs were subsequently inoculated with 1 of the following microorganisms: Enterococcus faecalis (ATCC 19433), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 15442), or Geobacillus stearothermophilus (ATCC 7953). Twenty-four hours after inoculation, the burs in group 2 and groups 4 to 7 were subjected to the cleaning treatments and sterilized with steam. The burs in all 7 groups were then cultured for bacterial contamination. No growth of any bacterial type was observed in any of the groups except the positive control group. The use of a cleaning stone in combination with manual or ultrasonic cleaning resulted in the least amount of remaining tooth debris on the diamond-coated burs. The contaminated and inoculated diamond-coated burs tested in this study were successfully sterilized, and the tested bacteria were eliminated. If using a diamond-coated bur multiple times, practitioners should consider utilizing debridement with a cleaning stone followed by either manual or ultrasonic cleaning and then by a single cycle of steam sterilization., Competing Interests: The views expressed are those of the authors and do not reflect the official views or policies of the Uniformed Services University, US Air Force, Department of Defense, or US government. The authors report no conflicts of interest pertaining to any of the products or companies discussed in this article.

This study utilized a statistical nanoindentation analysis technique (SNT) to measure the amount of organic and inorganic constituents of twenty different brands of dental resin-based composites (RBCs) and tested whether their macro-property such as flexural modulus could be approximated by the proportions of constituents' micromechanical signatures using various rules of mixtures. The probability density function (PDF) of constitutive moduli per RBC brand were measured for three groups, comprised of different indent arrays and inter-indent spacings. SNT was then applied to deconvolute each PDF, from which the effective filler (μ F ) and matrix (μ M ) moduli and filler (V F ) and matrix (V M ) volume fractions per RBC brand were computed. V F and V M values obtained via SNT were strongly correlated with V F and V M obtained via Thermogravimetric Analysis and Archimedes method. The "observed" flexural modulus (E c FS ) measured under macro-experiment were well associated with "predicted" effective modulus (E c Eff ) measured under nano-experiment, thereby establishing that global modulus was strongly affected by the constituents' micromechanics. However, the "predicted" E c Eff were proportionally higher than the "observed" E c FS . V F was a confounder to E c FS and E c Eff , whereby the influence of V F on both modular ratios (E c FS /μ M and E c Eff /μ M ) was best modeled by an exponential regression., (Published by Elsevier Ltd.)

Objective: CAD-CAM has dramatically advanced dental restorative procedures to include implant-supported crowns. The purpose of this study was to compare the fracture resistance following mechanical loading and thermocycling of various screw-retained and cement-retained ceramic and polymethylmethacrylate material combinations using the TiBase abutment compared to PFM implant-supported crowns., Overview: Twelve implant restorations were fabricated for each of eight groups. Three groups were screw-retained and five groups were cement-retained implant restorations. The ceramic and polymethylmethacrylate restorations were fabricated on the TiBase abutment while the PFM restorations were fabricated on an UCLA abutment. Data were analyzed with a one way Analysis of Variance and Tukey's post-hoc test to evaluate the effect of abutment and crown type on fracture load (alpha = 0.05). A significant difference was found in the maximum fracture load between groups (P < 0.001)., Conclusions: The screw-retained implant restorations demonstrated higher fracture loads than their cement-retained counterparts. The TiBase abutment compared favorably to the UCLA abutment., Clinical Significance: The TiBase abutment is a titanium insert which combines the esthetics of a ceramic abutment with the mechanical properties of a titanium abutment and should be considered a viable clinical alternative to the conventional implant-supported PFM crown based on theses in vitro results and in context of in vivo studies. The lithium disilicate hybrid abutment/crown implant-supported restoration utilizing the TiBase abutment may be an ideal clinical choice due to simplicity, single appointment CAD-CAM, and esthetics., (© 2020 Wiley Periodicals LLC.)

Background: The purpose of this study was to evaluate the use of a stress ball as a distraction technique on stress levels of patients undergoing a dental procedure., Material and Methods: A randomized, split-mouth design was conducted using 20 adult subjects requiring scaling and root planing (Sc/RP) in all four quadrants. Each side of the mouth (maxillary/mandibular) received Sc/RP with local anesthetic with or without the use of a stress-ball distraction over two separate sessions. Subjects completed two pre-procedural questionnaires (Spielberger State-Trait Anxiety Inventory, STAI; Modified Dental Anxiety Scale, MDAS) before and after each treatment session. A Galvanic Skin Response (GSR) sensor (Neulog) was used throughout each session to measure skin conductance or sweat., Results: No significant difference in GSR scores was found during treatment with or without the use of the stress ball. Also, no significant differences in the change in STAI or MDAS scores were found with or without the use of a stress ball., Conclusions: The results of this study found that the use of a stress ball as a distraction technique did not result in any significant reduction in stress levels in subjects undergoing scaling and root planing with local anesthesia. Key words: Anxiety, distraction, stress ball., Competing Interests: Conflicts of interest The authors do not have any financial interest in the companies whose materials are discussed in this manuscript., (Copyright: © 2021 Medicina Oral S.L.)

Statement of Problem: If a composite resin-veneered polyetheretherketone (PEEK) restoration chips or fractures, a repair may be indicated. However, the most appropriate repair protocol for a composite resin-veneered PEEK restoration is unclear., Purpose: The purpose of this in vitro study was to determine the efficacy of airborne-particle abrasion and/or a primer in the repair of composite resin-veneered PEEK prostheses., Material and Methods: PEEK specimens (N=80) were airborne-particle abraded with alumina before being conditioned with a methyl methacrylate-based primer. A thin layer of opaquer was applied, and a split mold was then filled with a veneering resin. The specimens underwent 5000 thermocycles, and then shear bond strength (SBS) was determined and used as the positive control group. Specimens that failed in either mixed or adhesive modes were contaminated with saliva and then exposed to 4 different repair treatment methods: no airborne-particle abrasion, bonded without a primer (negative control group); airborne-particle abrasion, bonded without a primer; no airborne-particle abrasion, bonded with a primer; and airborne-particle abrasion, bonded with a primer. All specimens had opaquer applied before being veneered. Repaired specimens then underwent thermocycling before SBS testing. Data were analyzed via ANOVA with a Newman-Keuls post hoc test (α=.05)., Results: The SBS values for the negative control were significantly lower than those of all other repair groups and the control group (P<.018). No significant differences in the SBS values were found among these other repair groups or the positive control group (P>.05)., Conclusions: Composite resin-veneered PEEK restorations or prostheses repaired with airborne-particle abrasion and/or primer can provide SBS comparable with that of the initial SBS., (Copyright © 2020 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The purpose of this study was to investigate the manufacturer's claims regarding a novel needleless intraligamentary local anesthesia injection device (Numbee, BioDent) to provide effective single tooth anesthesia. Investigators compared the Numbee with a traditional inferior alveolar nerve block (IANB) during a restorative procedure on mandibular teeth. A randomized, split-mouth design was conducted with 15 adult subjects receiving an IANB on one side and a Numbee injection on the same tooth type on the contralateral side. Subjects recorded injection pain using the Visual Analog Scale (VAS) and their preferred injection technique. Anesthesia was considered profound with 2 consecutive electric pulp tester readings of 80. If subjects became symptomatic during the restorative procedure, rescue anesthesia was administered. The difference in VAS scores for injection pain between the Numbee and the IANB was not significant (p = .078). For the IANB, the incidence of profound anesthesia was 46%, and required rescue anesthesia was 20%. For the Numbee, the incidence of profound anesthesia was 0%, and required rescue anesthesia was 60%. Subject preference was evenly split (50/50%) between the 2 techniques. The IANB outperformed the Numbee device for achieving profound anesthesia and requiring less rescue anesthesia., (© 2020 by the American Dental Society of Anesthesiology.)

Aim and Objective: The purpose of this study was to examine the effects of toothbrushing on the change in color of extrinsic characterization of ceramic-polymer materials., Materials and Methods: Two ceramic-polymer materials (CeraSmart, GC; Enamic, VITA) and one lithium-disilicate material (IPS e.max CAD; Ivoclar Vivadent) were tested. Specimens of each material were prepared, characterized, and glazed per manufacturer's instructions. The treated surface of the blocks were then brushed in a toothpaste slurry with artificial saliva using a toothbrush machine with a soft toothbrush. Commission Internationale de L'Eclairage (CIE) L*a*b* values were recorded with a spectrophotometer at baseline and at 3, 6, 9, and 12 simulated years of brushing (7,300 strokes/year). A mean change in color (Δ E *) and standard deviation was determined for each group and brushing interval. Data were analyzed with a two-way repeated measures ANOVA examining the effects of toothbrushing the ceramic materials on Δ E * over time (α = 0.05)., Results: The difference in the Δ E * between CeraSmart and Enamic was significant at 3 years, while the differences between them were not significant at 6, 9, and 12 years of simulated brushing. The Δ E * of IPS e.max CAD was significantly lower than CeraSmart and Enamic at all time points (all p < 0.0001) except for the comparison with Enamic at 3 years., Conclusion: The extrinsic stains on the ceramic-polymer materials may be more susceptible to change from simulated toothbrushing compared to the lithium-disilicate material., Clinical Significance: Toothbrushing may change the color of extrinsic characterization of ceramic-polymer materials. However, the change may remain clinically imperceptible to the naked eye (Δ E * > 1.0) for nearly 6 equivalent years of brushing.

Clinical Relevance: Mechanical surface roughening of the titanium-abutment base is necessary to increase the pull-off bond strength of the lithium disilicate abutment material. Additional chemical surface treatment may further increase the bond strength, but the effects are product specific., (©Operative Dentistry, 2020.)

Aim: The purpose of this study was to evaluate the effects of air abrasion with aluminum oxide or glass beads to three types of zirconia containing various levels of cubic crystalline phases (3Y-TZP, Katana ML; 4Y-PSZ, Katana STML; and 5Y-PSZ, Katana UTML, Noritake) on the shear bond strength of resin cement., Materials and Methods: Thirty block specimens (8 × 8 × 3.5 mm) were milled out of each zirconia material and mounted in plastic pipe. Ten specimens of each of the zirconia materials were air-abraded using 50 μm aluminum oxide particles, ten specimens were abraded using 80 μm glass beads, and ten specimens served as a control and received no surface treatment. A zirconia primer was applied to the surface of the zirconia specimens. Composite disks were bonded using a resin cement and light-cured. The specimens were stored in 37°C distilled water for 24 hours and thermocycled for 2,500 cycles. The specimens were loaded in shear on a universal testing machine. Data were analyzed with one-way and two-way ANOVAs and Tukey's post hoc tests ( α = 0.05)., Results: A significant difference in shear bond strength was found based on the surface treatment ( p < 0.001), but not on the type of zirconia ( p = 0.132)., Conclusion: Air abrasion with glass beads or no surface treatment resulted in significantly lower bond strength of the resin cement to all three zirconia types compared to air abrasion with aluminum oxide., Clinical Significance: Although air abrasion with aluminum oxide may reportedly be more likely to weaken cubic-containing zirconia compared to air abrasion with glass beads, the use of aluminum oxide results in greater bond strength of the resin cement.

The reported advantage of new dual-cured adhesive agents is that they do not require light curing, resulting in a reduced film thickness and improved seating of bonded all-ceramic restorations. The purpose of this study was to determine the effect of dual-cured adhesives on the bond strength of dual-cured resin cement to dentin under different polymerization conditions: with or without light curing of the dual-cured adhesive as well as with or without light curing of the dual-cured resin cement through a lithium disilicate ceramic material. Human molars were sectioned to remove the coronal tooth structure and randomly divided into 3 adhesive groups: Clearfil SE Bond 2, ExciTE F DSC, and Universal Primer. The adhesive agents were applied to the dentin surface with or without light activation. A dual-cured resin cement was applied, and discs of lithium disilicate were cemented to the dentin surface. Half of the discs were light cured from the top surface, and the other half were allowed to self-cure. Shear bond strength was tested after storage in distilled water for 24 hours. The effect of light curing of the adhesive or cement on the shear bond strength of the lithium disilicate discs to dentin was product dependent. Clearfil SE Bond 2 performed significantly better with light curing of both the adhesive and cement. Less significant effects of the various light-curing and self-curing combinations were observed with ExciTE F DSC or Universal Primer. When neither the adhesive nor the cement was light cured, all 3 adhesives performed poorly and had a significant loss in bond strength., Competing Interests: The authors report no conflicts of interest pertaining to any of the products or companies discussed in this article. The views expressed in this article are those of the authors and do not reflect the official policy of the US Air Force, the Department of Defense, Uniformed Services University of the Health Sciences, or the US government.

Aim: The aim of this research was to determine whether sterilization and reutilization of impression copings had an impact on the accuracy of casts made for multiimplant restorations., Materials and Methods: Four master casts embedded with five implant analogs were fabricated. Polyvinyl siloxane (PVS) impressions of the master cast with copings attached to the analogs were made and poured in dental stone. The impression copings were subjected to cleaning and sterilization. These processes were repeated 30 cycles for each of the two groups of five impression copings: one without modification and one with modification that included air abrasion and PVS adhesive. A coordinate measuring machine (CMM) was used to measure relative angles and distances between the reference analog and analogs. The relative angles and distances measured on the stone casts were compared to the master resin cast to obtain positional and angular displacements., Results: For impression copings that were not modified, a significant difference was detected for both positional and angular displacements. For impression copings that were modified, a significant change was observed only for positional displacement. The maximum discrepancies measured for positional and angular displacements after 30 cycles of reuse were only 81 μm and 0.46°, respectively, regardless of the modification., Conclusion: Within the limitations of this study, unmodified impression copings that have undergone 30 cycles of cleaning and sterilization appeared to incur more impression inaccuracy than those impression copings that were modified by airborne-particle abrasion and PVS adhesive., Clinical Significance: Impression copings used in this study can likely be recycled up to 30 times without reducing the accuracy of the impression to a level that may be considered clinically significant.

Aim: The purpose of this study was to survey all United States Air Force (USAF) general dentists regarding their experience with computer-aided design/computer-aided manufacturing (CAD/CAM) while in a dental school. Dental school graduation year and location was compared to the type and amount of CAD/CAM training and clinical experience during dental school to better understand the differences and influence of this technology., Materials and Methods: A survey consisting of six questions was sent through e-mail to 546 general dentists in the AF Dental Corps in 2018 of which 306 replied (56% response rate)., Results: Dentists who graduated in 2005 or earlier and between 2006 and 2009 stated they did not receive CAD/CAM training in dental school, while more respondents in the group of graduation years 2014-2017 stated that they did receive training. About 11% of the respondents who graduated in 2014-2017 completed 6-10 restorations and 9% completed 11 or more restorations compared to the other year groups. More respondents who graduated from a dental school in the southwest and southeast regions of the United States reported completing more restorations compared to other school regions., Conclusion: Computer-aided design/computer-aided manufacturing is now becoming a prevalent curriculum in US dental schools, both as a core requirement and an elective. Its training platforms varied from lectures and literature reviews to preclinical laboratory., Clinical Significance: More respondents in the groups of graduation years 2014-2017 had completed more CAD/CAM restorations compared to other year groups; however, most of the respondents did not feel their training was sufficient enough to use CAD/CAM technology independently.

Aim: Newer zirconia materials may have greater strength degradation under cyclic fatigue with increased yttria and cubic content. The purpose of this study was to evaluate the flexural strength (FS) degradation of newer zirconia materials compared to more traditional tetragonal zirconia materials., Materials and Methods: The following materials were tested: two 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) materials (Lava Plus, 3M ESPE; Katana ML, Kuraray), one 4 mol% partially stabilized zirconia (4Y-PSZ) material (Katana STML, Kuraray), two 5 mol% partially stabilized zirconia (5Y-PSZ) materials (Katana STML, Kuraray; Lava Esthetic, 3M ESPE), and one lithium disilicate material (IPS e.max CAD LT, Ivoclar Vivadent). Thirty beams were milled for each ceramic material with final dimensions of 4.0 × 1.3 × 18.0 mm after sintering or crystallization. Each specimen was placed on a 3-point bend test device on a universal testing machine (Instron, Norwood, MA). Flexural strength was determined on 10 beam specimens per group with a central load applied until fracture. Flexural fatigue strength was then measured on the remaining 20 beam specimens per group using the staircase method for 6,000 cycles at 2 Hz. Data were analyzed with one-way ANOVAs/Tukey post hoc tests ( α = 0.05)., Results: A significant difference was found between groups ( p < 0.001) per property. The 3Y-TZP zirconia materials had the greatest flexural and flexural fatigue strength. The cubic containing zirconia materials performed more moderately. The lithium disilicate material had the lowest strength values. The percent degradation in flexural fatigue strength of the 3Y-TZP zirconia materials was less than the 5Y-PSZ, Katana UTML, and the 4Y-PSZ, Katana STML, cubic containing materials, but similar to the 5Y-PSZ cubic containing material, Lava Esthetic., Conclusion: The amount of strength degradation was material dependent, with the 4Y-PSZ or 5Y-PSZ cubic containing zirconia materials demonstrating greater or similar strength degradation compared to the primarily tetragonal 3Y-TZP zirconia materials., Clinical Significance: The differences in FS degradation between cubic containing materials and traditional zirconia materials could significantly impact the long-term success of these newer materials. Clinicians should be aware that these cubic containing materials may perform differently long-term than the very strong traditional 3Y-TZP materials and to follow manufacturer instructions on required material thickness and indications for use to prevent premature failure of the restoration.

Digital dentistry has led to the success of same-day, single-crown delivery. Unlike traditional convection furnaces for fabrication of zirconia materials, which typically require several hours to complete sintering, a dedicated high-speed sintering furnace that reportedly sinters zirconia in minutes is now available. Sintering times may increase or decrease based on the size of the restoration due to a novel interface between the chairside acquisition unit, milling unit, and furnace. The purpose of this study was to compare the flexural properties (strength and modulus), optical parameters (translucency and opalescence), and grain size of a full-contour tetragonal zirconia material after sintering in either a novel high-speed furnace or a conventional zirconia furnace. Rectangular zirconia beams were milled and sintered using the high-speed induction furnace for 26.2 minutes or a conventional convection furnace for 4.3 hours. Flexural strength and modulus were determined by subjecting the beams to a 3-point bending test in a materials testing machine. Translucency and opalescence were calculated using a spectrophotometer, and grain size was determined by using an atomic force microscope. The dedicated high-speed induction furnace sintered the tetragonal zirconia specimens in substantially less time than the conventional convection furnace, with a statistically significant decrease in grain size and no significant difference in strength or optical properties., Competing Interests: Dentsply Sirona loaned the SpeedFire furnace used in this study as part of a Material Transfer Agreement with the US Air Force. The views expressed in this article are those of the authors and do not reflect the official policy of the US Air Force, the Department of Defense, Uniformed Services University of the Health Sciences, or the US government. The authors do not have any financial interest in the companies whose materials are discussed in this article.

Aim: The purpose of this study was to evaluate the effectiveness of several methods of disinfection and sterilization of computer-aided design/computer-aided manufacturing (CAD/CAM) camera mirror sleeves (Omnicam; Dentsply Sirona)., Materials and Methods: The outer surface of seven groups of mirror sleeves were inoculated by submerging them in suspensions of Staphylococcus aureus and Pseudomonas aeruginosa. Post inoculation, the groups were decontaminated as follows: Group A: no decontamination or sterilization following inoculation (positive control); Group B: surface cleaning with a neutral soap (Dawn Dish Soap, Procter & Gamble) and water only; Group C: surface disinfection with 17% isopropanol (CaviWipes; Metrex). Groups D to F received a different high-level disinfection (HLD) solution in an HLD container (Dentsply Sirona) as follows: Group D: 0.55% ortho-phthalaldehyde (OPA) (Cidex OPA; Johnson & Johnson); Group E: 7.5% hydrogen peroxide (H2O2) (Sporox II; Sultan); Group F: 7.35% H2O2 and 0.23% peracetic acid (PAA) (Compliance; Metrex). Group G received dry-heat sterilization (Rapid Heat Sterilizer; Cox). Also, dry-heat sterilized mirror sleeves that were not exposed to bacteria and not disinfected served as a negative control. The presence of bacteria was tested on the inside and outside of the sleeves by plating samples on TSA II. A percent reduction in CFU/ml from the positive control group was determined per group., Results: All methods of disinfection except Dawn Dish Soap resulted in greater than 99.99% reduction in CFU/ml compared with the positive control group., Conclusions: Both HLD or dry-heat sterilization resulted in no growth of microorganisms in cultures taken from both the outside and inside surfaces of the bacteria-contaminated mirror sleeves.

A new nanofiber-reinforced hybrid composite (NovaPro Fill, Nanova) was recently introduced with reportedly improved mechanical properties. The purpose of this study was to compare the properties (flexural strength/modulus, degree of conversion [DC], depth of cure, and polymerization shrinkage) of the nanofiber composite to those of traditional hybrid composites (Filtek Z250, 3M ESPE; Esthet-X HD, Dentsply). To determine flexural strength and modulus, composite was placed in a rectangular mold, light-cured, stored for 24 hours, and then fractured in a universal testing machine. For degree of conversion, composite was placed in a cylindrical mold, light-cured, and stored for 24 hours. Measurements were made at the top and bottom surfaces using Fourier Transform Infrared Spectroscopy. To determine depth of cure, composite was placed in a cylindrical mold and light-cured. Uncured composite was scraped until polymerized resin was reached. Remaining composite was measured and divided by two. Polymerization shrinkage was determined by placing the composite material on a pedestal in a video-imaging device while light-curing. Shrinkage was determined after 10 minutes. Data were analyzed with one-way analysis of variance and Tukey post hoc test per property (α=0.05). Compared to Filtek Z250, NovaPro Fill had significantly lower flexural strength and modulus, greater volumetric shrinkage, and similar depth of cure, but greater top and bottom DC. Compared to Esthet-X HD, NovaPro Fill had similar flexural strength, shrinkage, and top and bottom DC, but significantly greater depth of cure and flexural modulus.

New ceramic-polymer millable materials that may be less resistant to the abrasive effects of toothbrushing than glass-ceramic materials have been introduced recently. The purpose of this study was to evaluate the polish retention of ceramic-polymer materials after mechanical toothbrush abrasion. Four ceramic-polymer materials (Enamic, Lava Ultimate, CeraSmart, and Block HC) were compared to a lithium disilicate glass-ceramic material (IPS e.max CAD). After 10 specimens of each material were polished, baseline area surface roughness (Sa) measurements were made. Specimens were then placed in a toothbrushing machine for 60,000 strokes, simulating 8 years of brushing. Surface roughness measurements were repeated after 30,000 and 60,000 brush strokes. At the end of the brushing, IPS e.max CAD and Enamic had the lowest mean Sa values (0.50 [SD 0.17] and 0.55 [0.13] µm², respectively), while Block HC had the greatest (1.10 [0.10] µm²). Lava Ultimate and CeraSmart demonstrated intermediate Sa values (0.81 [0.14] and 0.72 [0.11] µm², respectively). Only IPS e.max CAD had no statistically significant increase in surface roughness after toothbrushing., Competing Interests: Disclaimer: The views expressed in this article are those of the authors and do not reflect the official policy of the US Air Force, the Department of Defense, Uniformed Services University of the Health Sciences, or the United States government. The authors report no conflicts of interest pertaining to any of the products or companies discussed in this article.

Objectives: The purpose of this study was to investigate the effect of high-irradiance light-curing-units (LCUs) on the depth-of-cure (DoC) and degree-of-polymerization (DoP) of bulk-fill composites (BFCs)., Methods: The DoC of composites (Beautifil-Bulk, SHOFU; Filtek-Bulk-Fill, 3M ESPE; Tetric-EvoCeram-Bulk-Fill, Ivoclar; Sonic-Fill-2, Kerr; Venus-Bulk-Fill, Heraeus; Z250, 3M-ESPE) were measured according to ISO-4049 using high-irradiance LCUs (FlashMax-P3, CMS-Dental; SPEC3, Coltene) and conventional LCU (Paradigm, 3M-ESPE) for exposure times: 3/9-s, 3/20-s, and 10/20-s respectively. Using FTIR, the DoP per composite was measured at the bottom surface as a function of post-curing times for the LCUs at the same exposure times. Data was analyzed with nonlinear regression and ANOVA/Tukey., Results: Significant differences in DoC were found amongst the LCUs for the various exposure times. All BFCs failed to meet the DoC claimed by manufacturers and failed to satisfy ISO-4049 with the high-irradiance LCUs with 3-s exposures. Standard irradiance and 20-s exposures outperformed all other irradiance-exposure combinations for maximizing the DoC and DoP of BFCs. A minimum of 15.3J/cm 2 radiant exposure was required to achieve an adequate maximum polymerization rate. Venus Bulk exhibited the highest DoC and DoP for any LCU-exposure-time combination., Significance: Among the different combinations of BFCs and LCUs, DoC and DoP were always increased with longer exposure time, but there exists a theoretical radiant-exposure limit beyond which DoP or DoC remains unchanged. However, high DoC or DoP are not always associated with one another. Thus, the exposure-reciprocity law must be approached thoughtfully since irradiance and exposure can independently affect DoP and DoC., (Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.)

Manufacturers have recently introduced surface primers and pretreatment solutions that reportedly simplify the bonding process of resin cements to ceramics through various combinations of etchant and coupling agents. This study evaluated the shear bond strength (SBS) of a resin cement to a lithium disilicate glass-ceramic material pretreated with various new surface treatment solutions and compared the results to those of a control group prepared with the traditional application of hydrofluoric acid (HF) and silane. Resin cement was bonded to pretreated glass-ceramic surfaces, and specimens were tested for SBS after 24 hours of storage in water. Traditional surface treatment of lithium disilicate glass ceramic with HF and silane resulted in a significantly greater mean SBS than did simplified primer solutions. There were no statistically significant differences among the simplified pretreatment groups. In the control group, the majority of failures were due to mixed adhesive-cohesive fracture, while in the simplified treatment groups the failure mode was usually adhesive, suggesting a weaker interface., Competing Interests: Disclaimer: The views expressed in this article are those of the authors and do not reflect the official policy of the US Air Force, the Department of Defense, Uniformed Services University of the Health Sciences, or the US government. The authors report no conflicts of interest pertaining to any of the products or companies discussed in this article.

Purpose: To evaluate the fracture resistance of a newer lithium disilicate abutment material., Materials and Methods: A premolar-shaped implant crown was designed using CAD/CAM software, and four groups of implant and crown combinations were milled: (1) lithium-disilicate hybrid-abutment crown; (2) "screwmentable" lithium-disilicate hybrid abutment/lithium-disilicate crown with screw channel; (3) lithium-disilicate hybrid abutment/lithium-disilicate crown; and (4) zirconia hybrid abutment/lithium-disilicate crown (control). The specimens were cemented to a titanium-base implant system, subjected to thermocycling and cyclic loading, and fractured in a material testing device., Results: The lithium-disilicate hybrid-abutment crown had significantly greater fracture load than all the other groups, which were not significantly different from each other., Conclusions: Based on fracture load, the new lithium-disilicate hybrid-abutment material may serve as a viable alternative to the use of zirconia as a hybrid-abutment material., (© 2018 by the American College of Prosthodontists.)

The purpose of this study was to evaluate the fracture resistance of teeth with standard or extended mesio-occlusodistal (MOD) preparations after restoration with bonded computer-aided design/computer-aided manufacturing (CAD/CAM) materials. Standard or extended MOD cavities were prepared in 60 of 70 extracted, caries-free third molars. In the standard MOD preparations (n = 30), 4.5- mm buccal and lingual/palatal wall thickness remained, and proximal boxes extended 1.0 mm coronal to the cementoenamel junction. In the extended MOD preparations (n = 30), the buccal and lingual/palatal walls were reduced to a thickness of 3.0 mm. A CAD/CAM acquisition unit was used to scan 20 standard and 20 extended preparations. Subsequently, 10 standard and 10 extended preparations were restored with milled lithium disilicate, and 10 of each type were restored with resin nanoceramic. Ten of each preparation type were left unrestored (negative control). An additional 10 third molars were neither prepared nor restored (positive control). After thermocycling and cyclic loading, specimens were fractured in a material testing device. Although bonded CAD/CAM restorations reinforced the tooth structure, the mean fracture loads were significantly lower (P < 0.05) in teeth with restored extended preparations (2642.4 [SD 479.4] N) than in teeth with restored standard preparations (3376.6 [SD 817.9] N). The type of CAD/CAM restorative material did not significantly affect the fracture load. Practitioners should consider covering the cusps with a CAD/CAM restorative material to reduce the potential for fracture in preparations with reduced cuspal thickness, especially in patients with heavier occlusion or functional loads., Competing Interests: Disclaimer: The views expressed in this article are those of the authors and do not reflect the official policy of the US Air Force, Department of Defense, Uniformed Services University of the Health Sciences, or US government. The authors report no conflicts of interest pertaining to any of the products or companies discussed in this article.

The purpose of this study was to compare the depths of cure of a proximal box preparation filled in bulk with various approaches: filled with a bulk-fill or conventional composite; placed with a new perforated metal matrix, a traditional metal matrix, or a clear matrix; and polymerized with either occlusal-only or tri-sited light curing. After tri-sited curing, the use of the new perforated metal matrix band resulted in a depth of cure that was not significantly different from that achieved with the use of metal bands (removed during curing) or transparent matrix bands. Adequate polymerization was obtained at depths of more than 5.0 mm for the bulk-fill composite and more than 4.0 mm for the conventional composite when tri-sited light curing was used. Tri-sited light curing resulted in a significantly greater depth of cure than occlusal-only curing. The perforated metal band may be used as an alternative to the use of solid metal bands or transparent matrix bands to provide similar depths of cure for composite resins, with the possible benefits of malleability and the ability to leave the band in place during tri-sited light curing., Competing Interests: Disclaimer: The views expressed in this article are those of the authors and do not reflect the official policy of the US Air Force, the Department of Defense, Uniformed Services University of the Health Sciences, or the US government. The authors report no conflicts of interest pertaining to any of the products or companies discussed in this article.

Objective: The purpose of this study was to compare the effectiveness of detecting proximal carious lesions utilizing a new near-infrared transillumination (NIRTI) system (CariVu, Dexis) to traditional digital bitewing radiography (BWXR)., Materials and Methods: Thirty patients received four posterior BWXRs and all premolars and molars were individually imaged with the NIRTI device. Sixty-seven proximal carious lesions were classified based on their depth into enamel or dentin for both BWXR and NIRTI images., Results: The caries depth classification between the two systems were strongly correlated (r s  = 0.66; Spearman range: 0.60-0.79 = strong) and significant (P < .001) with a median score of 3 for NIRTI and 2 for BWXR., Conclusions: The new NIRTI system (CariVu) may serve as an adjunct to BWXR in the diagnosis of proximal caries., Clinical Significance: The NIRTI system could serve as an adjunct diagnostic system that could be used in high-caries risk programs where patients are closely monitored with regimented follow-up appointments. NIRTI could also be beneficial with pregnant or pediatric patients, and in situations where radiography may not be available such as remote humanitarian missions., (© 2017 Wiley Periodicals, Inc.)

The purpose of this study was to compare the whitening efficacy of a novel bleaching agent containing a unique tribarrel hydremide-peroxide gel (KöR) with a traditional bleaching system of hydrogen peroxide or carbamide peroxide (Opalescence). Bovine incisors were mounted into a custom resin, arch-shaped mounting device. Four groups of 10 teeth were created using mounting devices containing five teeth each. The in-office and home bleaching gels of KöR and Opalescence were applied to the teeth alone and in trays to simulate a combination of in-office and home bleaching or home bleaching only. Spectrophotometer readings of L* a* b* were performed at baseline, the end of active bleaching (immediate), and three and six months postbleaching. Immediately postbleaching, the use of Opalescence gel resulted in greater change in ΔE* and Δb* (less yellow) for combined and home bleaching techniques compared with KöR. After six months, Opalescence had significantly greater ΔE* and Δb* compared with KöR for home bleaching only. There was no significant difference in ΔL* between Opalescence and KöR at any time period with either technique.

The carving of a complex amalgam restoration may occasionally result in light proximal contact with the adjacent tooth. The purpose of this study was to investigate the strength of complex amalgam restorations repaired with a proximal slot amalgam preparation. Extracted human third molars of similar coronal size were sectioned 1 mm apical to the height of the contour using a saw and were randomly distributed into 9 groups of 10 teeth each. One pin was placed at each line angle of the flattened dentinal tooth surface. A metal matrix band was placed and an admixed alloy was condensed and carved to create a full crown contour but with a flat occlusal surface. A proximal slot was prepared with or without a retention groove and repaired using a single-composition spherical amalgam 15 minutes, 24 hours, one week, or six months after the initial crown condensation. The specimens were stored for 24 hours in 37°C water before fracture at the marginal ridge using a round-ended blade in a universal testing machine. The control group was not repaired. The mean maximum force in newtons and standard deviation were determined per group. Data were analyzed with a 2-way analysis of variance as well as Tukey and Dunnett tests (α=0.05). Significant differences were found between groups based on type of slot preparation (p=0.017) but not on time (p=0.327), with no significant interaction (p=0.152). No significant difference in the strength of the marginal ridge was found between any repair group and the unrepaired control group (p>0.076). The proximal repair strength of a complex amalgam restoration was not significantly different from an unrepaired amalgam crown. Placing a retention groove in the proximal slot preparation resulted in significantly greater fracture strength than a slot with no retention grooves. Time of repair had no significant effect on the strength of the repair.

A new fluoride-releasing sealant system is claimed to allow easier and faster placement while providing high bond strengths without the need for phosphoric acid etching. A study was designed to compare the microleakage and shear bond strength of a self-etching, Giomer-based sealant system with those of a traditional resin sealant. Group 1 received traditional sealant applied after use of a 35% phosphoric acid etchant; group 2 received Giomer sealant after use of a self-etching primer; and group 3 received Giomer sealant after the addition of an initial phosphoric acid etching step and placement of the primer. The sealants were placed in the occlusal pits and fissures of extracted human third molars, thermocycled, placed in dye, and sectioned. The extent of microleakage (dye penetration) was expressed as a percentage of the cross-sectional length of the sealed interface. The sealants were also bonded to the facial enamel of bovine incisors. Specimens were thermocycled and tested in shear mode in a universal testing machine. The new self-etching sealant demonstrated significantly greater microleakage (P < 0.017) and lower bond strength (P < 0.05) than both the traditional sealant system and the new system when placed with phosphoric acid etchant. Phosphoric acid etching significantly improved the shear bond strength and reduced the microleakage of the new sealant., Competing Interests: Disclaimer: The views expressed in this article are those of the authors and do not reflect the official policy of the US Air Force, the Department of Defense, the Uniformed Services University of the Health Sciences, or the US government. The authors do not have any financial interest in the companies whose materials are discussed in this article.

The purpose of this study was to evaluate the translucency and strength of highly translucent monolithic zirconia ceramic materials recently introduced to the market. Four monolithic zirconium oxide materials promoted as having high translucency (BruxZir Shaded 16, BruxZir HT, Lava Plus, and inCoris TZI C) were compared to a high-translucency, lithium disilicate monolithic glass-ceramic material (IPS e.max CAD HT). To evaluate translucency, the materials were sectioned into 0.5-, 1.0-, 1.5-, and 2.0-mm-thick specimens; all were sintered and polished. Translucency parameters were calculated with a spectrophotometer. To evaluate flexural strength and modulus, the ceramic materials were sectioned to create beams and fractured in a universal testing machine. The lithium disilicate had significantly greater translucency than the zirconia materials at each thickness. In general, the translucencies of the zirconia materials were similar at each thickness. However, at the manufacturers' recommended minimal thicknesses, 0.5-mm specimens of BruxZir Shaded 16, inCoris TZI C, and Lava Plus were more translucent than the 1.0-mm-thick specimens of IPS e.max CAD HT. Translucency significantly decreased for each material at each increase in thickness. The flexural strengths of the zirconia materials were similar to each other and significantly greater than that of IPS e.max CAD HT. Flexural moduli were more variable. Of the zirconia materials, BruxZir Shaded 16 had an overall better combination of translucency, strength, and modulus.