Current speed sintering and high-speed sintering protocols compromise the translucency but not strength of yttria-stabilized zirconia.

OBJECTIVES: To investigate the impacts of speed and high-speed sintering on the densification, microstructure, phase composition, translucency, and flexural strength of yttria-stabilized zirconia (YSZ). METHODS: A total of 162 disc-shaped specimens (n = 18) were cold-isostatically pressed from 3YSZ (Zpex), 4YSZ (Zpex 4), and 5YSZ (Zpex Smile) powders (Tosoh Corporation) and sintered according to the following protocols: conventional (control, ∼12 h), speed (∼28 min for 3YSZ; ∼60 min for 4YSZ and 5YSZ), and high-speed (∼18 min) sintering. Dimensions of zirconia specimens after sintering and polishing (1-µm diamond grit finish) were Ø13.75 × 1 mm. Density, microstructure, phase content, translucency parameter, and biaxial flexural strength were evaluated using Archimedes', SEM, XRD, spectrophotometric, and piston-on-3-ball methods, respectively. Data were analyzed with either one-way ANOVA and Tukey's test or Kruskal-Wallis with Dunn's test (α = 0.05). RESULTS: For all YSZ compositions, conventional sintering yielded the highest density followed by speed then high-speed sintering. All sintering protocols resulted in similar strength values; however, speed and high-speed sintering protocols afforded significantly lower translucency relative to conventional sintering. XRD analysis revealed similar spectra for YSZs sintered by various protocols. The speed sintered specimens had the smallest grain size whereas the high-speed sintered 5YSZ possessed the largest grain size among all groups. SEM examination of all YSZ compositions revealed that the average pore size was an order of magnitude smaller than the average grain size. SIGNIFICANCE: Speed and high-speed sintering of YSZs yield similar strength but diminished density and translucency relative to their conventionally sintered counterparts.

Exploring dental students' attitudes toward patient-centered management of dental fear.

PURPOSE/OBJECTIVES: A patient-centered care (PCC) paradigm undergirds modern dental education. PCC is particularly relevant in the management of patient dental fear. The aims of this study were three-fold: (a) to examine the preliminary psychometric properties of an author-designed survey administered to explore dental fear knowledge and perceptions, (b) to assess how 4th-year dental students regard dental fear, (c) and to investigate the relationship between students' knowledge and perceptions of dental fear and their clinical behavior. METHODS: In 2022, 4th-year dental students (N = 453) participated in a cross-sectional study. Participants completed a 16-item survey that assessed (a) knowledge and perceptions about dental fear, (b) common biases in patient fear assessment, and (c) patient management behaviors when fear is encountered. Exploratory factor analysis, descriptive statistics, and logistic regressions were run to address the study's aims. RESULTS: Exploratory factor analysis revealed three factors, with the two strongest factors pertaining to beliefs about the importance of dental fear (α = 0.87) and self-efficacy in managing fear (α = 0.74). Participants indicated that it is important to assess for dental fear and rated their self-efficacy in ability managing it as high. Ratings on both factors slightly increased the odds of engaging in routine patient screening for dental fear. Students also displayed assessment biases commonly seen among practicing dentists. CONCLUSION(S): Results indicate educational gaps within the current behavioral-science training for dental students. Changes to improve advanced dental students' appreciation of their patients' dental fear are warranted.

Leveraging technology to increase the disseminability of evidence-based treatment of dental fear: An uncontrolled pilot study.

OBJECTIVES: U.S. and global estimates indicate that over 30% of adults fear receiving dental care, including over 20% who have visited a dentist in the last year, leading to avoidance and degraded oral and systemic health. Although evidence-based cognitive-behavioral treatments for dental fear (CBT-DF) exist, they have little impact on the millions who seek dental care annually because they are not disseminable (6 h of in-chair time, delivered only in person at a few sites). We developed a disseminable CBT-DF stepped-care treatment comprising (Step 1) a mobile-health application and, for those who remain fearful, (Step 2) a 1-h, one-on-one psychological treatment session that allows practice during exposure to the patient's most-feared stimuli. We hypothesized that the treatment would (a) be rated highly on usability and credibility and (b) result in clinically consequential (i.e., lowering fear into the 0-3 "no/low fear" zone) and statistically significant changes in global dental fear. METHOD: Racially/ethnically diverse patients (N = 48) with moderate to severe dental fear were recruited; all completed Step 1, and n = 16 completed Step 2. RESULTS: As hypothesized, users found the stepped-care treatment highly usable, credible, and helpful. Critically, this stepped-care approach produced reductions in patients' dental fear that were both clinically consequential (with half no longer fearful) and statistically significant (d = 1.11). CONCLUSIONS: This usable, credible, stepped-care approach to dental fear treatment holds promise for liberating evidence-based CBT-DF from specialty clinics, allowing broad dissemination.

Changes in Dental Outcomes After Implementation of the Philadelphia Beverage Tax.

INTRODUCTION: Beverage taxes are associated with declines in sugar-sweetened beverage sales and consumption, but few studies have evaluated the associations of these taxes with health outcomes. This study analyzed changes in dental decay after the implementation of the Philadelphia sweetened beverage tax. METHODS: Electronic dental record data were obtained on 83,260 patients living in Philadelphia and control areas from 2014 to 2019. Difference-in-differences analyses compared the number of new Decayed, Missing, and Filled Teeth with that of new Decayed, Missing, and Filled Surfaces before (January 2014-December 2016) and after (January 2019-December 2019) tax implementation in Philadelphia and control patients. Analyses were conducted in older children/adults (aged ≥15 years) and younger children (aged <15 years). Subgroup analyses stratified by Medicaid status. Analyses were conducted in 2022. RESULTS: The number of new Decayed, Missing, and Filled Teeth did not change after tax implementation in Philadelphia in panel analyses of older children/adults (difference-in-differences= -0.02, 95% CI= -0.08, 0.03) or younger children (difference-in-differences=0.07, 95% CI= -0.08, 0.23). There were similarly no post-tax changes in the number of new Decayed, Missing, and Filled Surfaces. However, in cross-sectional samples of patients on Medicaid, the number of new Decayed, Missing, and Filled Teeth was lower after tax implementation in older children/adults (difference-in-differences= -0.18, 95% CI= -0.34, -0.03; -22% decline) and younger children (difference-in-differences= -0.22, 95% CI= -0.46, 0.01; -30% decline), with similar results for number of new Decayed, Missing, and Filled Surfaces. CONCLUSIONS: The Philadelphia beverage tax was not associated with reduced tooth decay in the general population, but it was associated with reduced tooth decay in adults and children on Medicaid, suggesting potential health benefits for low-income populations.

Debulking different Corona (SARS-CoV-2 delta, omicron, OC43) and Influenza (H1N1, H3N2) virus strains by plant viral trap proteins in chewing gums to decrease infection and transmission.

Because oral transmission of SARS-CoV-2 is 3-5 orders of magnitude higher than nasal transmission, we investigated debulking of oral viruses using viral trap proteins (CTB-ACE2, FRIL) expressed in plant cells, delivered through the chewing gum. In omicron nasopharyngeal (NP) samples, the microbubble count (based on N-antigen) was significantly reduced by 20 µg of FRIL (p < 0.0001) and 0.925 µg of CTB-ACE2 (p = 0.0001). Among 20 delta or omicron NP samples, 17 had virus load reduced below the detection level of spike protein in the RAPID assay, after incubation with the CTB-ACE2 gum powder. A dose-dependent 50% plaque reduction with 50-100 ng FRIL or 600-800 µg FRIL gum against Influenza strains H1N1, H3N2, and Coronavirus HCoV-OC43 was observed with both purified FRIL, lablab bean powder or gum. In electron micrographs, large/densely packed clumps of overlapping influenza particles and FRIL protein were observed. Chewing simulator studies revealed that CTB-ACE2 release was time/dose-dependent and release was linear up to 20 min chewing. Phase I/II placebo-controlled, double-blinded clinical trial (IND 154897) is in progress to evaluate viral load in saliva before or after chewing CTB-ACE2/placebo gum. Collectively, this study advances the concept of chewing gum to deliver proteins to debulk oral viruses and decrease infection/transmission.

Penntorship: The value of mentoring during a pandemic.

COVID-19 presented learning and social challenges for dental and high-school students alike due to isolating environments with fewer interpersonal interactions. After recognizing these challenges, two pre-doctoral dental students developed Penntorship, a program at University of Pennsylvania, School of Dental Medicine, where dental students' mentor students at West Philadelphia High School (WPHS) utilizing online technology. PURPOSE: This survey study explored the benefits of a newly developed mentoring program, Penntorship, for mentors and mentees. METHODS: Seventy dental students volunteered to mentor WPHS students throughout the 2020-2021 school year. After receiving training by Mentor Independence Region, mentors coordinated weekly meetings with mentees on Zoom to assist with homework assignments, discuss interests, and assess mentee's career goals. Over six months, 185 mentor meetings were held by 56 dental students with 28 different high-school students participating in the program. Surveys were distributed and analyzed to determine outcomes of the program. RESULTS: Survey results revealed that both dental students and high-school students gained new friendships, improved communication skills, and developed a positive perspective during the pandemic. CONCLUSION: With online learning formats and social distancing during the pandemic, dental students expressed a need for more social interaction. Penntorship served to support dental students during this challenging year and filled a social need for young individuals in the community. Both mentors and mentees benefited from the program and will continue to work together in the coming academic year. *IRB approval obtained 8/30/2021.

Residual stresses explaining clinical fractures of bilayer zirconia and lithium disilicate crowns: A VFEM study.

OBJECTIVE: To understand the stress development in porcelain-veneered zirconia (PVZ) and porcelain-veneered lithium disilicate (PVLD) crowns with different veneer/core thickness ratios and cooling rates. To provide design guidelines for better performing bilayer restorations with the aid of Viscoelastic Finite Element Method (VFEM). METHODS: The VFEM was validated by comparing the predicted residual stresses with experimental measurements. Then, the model was used to predict transient and residual stresses in the two bilayer systems. Models with two different veneer/core thickness ratios were prepared (2:1 and 1:1) and two cooling protocols were simulated (Fast: ∼300 °C/min, Slow: ∼30 °C/min) using the heat transfer module, followed by stress analysis in ABAQUS. The physical properties of zirconia, lithium disilicate, and the porcelains used for the simulations were determined as a function of temperature. RESULTS: PVLD showed lower residual stresses than PVZ. The maximum tensile stresses in PVZ were observed in the cusp area, whereas those in PVLD were located in the central fossa. The 1:1 thickness ratio decreased stresses in both layers of PVZ. Slow cooling slightly decreased residual stresses in both systems. However, the cooling rate effect was more evident in transient stresses. SIGNIFICANCE: Slow cooling is preferable for both systems. A thinner porcelain layer over zirconia lowers stresses throughout the restoration. The different stress distributions between PVZ and PVLD may affect their failure modes. Smaller mismatches in modulus, CTE, and specific heat between the constituents, and the use of low Tg porcelains can effectively reduce the deleterious transient and residual tensile stresses in bilayer restorations.

Radiology of Dental Caries.

Dental caries is a dynamic, preventable, reversible, complex biofilm-mediated, multifactorial disease that involves a series of demineralization/neutrality/remineralization of dental hard tissue in primary and permanent dentition. An imbalance in the continuum with a net demineralization over time results in the initiation of caries lesions. Visual inspection and intraoral radiographs are vital in caries detection, although they are of suboptimal sensitivity for early caries lesions. Shifting toward a conservative, noninvasive approach to caries management has resulted in the development of innovative-sensitive technologies. These newer techniques may serve as adjunct for the dental practitioner in detecting earliest changes in tooth structure.

Diagnosis of Biofilm-Associated Peri-Implant Disease Using a Fluorescence-Based Approach.

Dental implants have become a routine component of daily dental practice and the demand for dental implants is expected to increase significantly in the future. Despite the high success rates of dental implants, failures do occur, resulting in discomfort, rampant destruction of the oral health, or painful and costly surgical replacement of a failed implant. Peri-implant diseases are inflammatory conditions affecting the soft/hard tissues surrounding a functional dental implant. Plenty of experimental evidence indicates that the accumulation of dental plaque at the soft tissue-implant interface and the subsequent local inflammatory response seems to be key in the pathogenesis of the peri-implant mucositis. Such peri-implant-soft tissue interface is less effective than natural teeth in resisting bacterial invasion, enhancing vulnerability to subsequent peri-implant disease. Furthermore, in certain individuals, it will progress to peri-implantitis, resulting in alveolar bone loss and implant failure. Although early diagnosis and accurate identification of risk factors are extremely important to effectively prevent peri-implant diseases, current systematic reviews revealed that a uniform classification and diagnostic methodology for peri-implantitis are lacking. Recent progress on fluorescence-based technology enabled rapid diagnosis of the disease and effective removal of plaques. Here, we briefly review biofilm-associated peri-implant diseases and propose a fluorescence-based approach for more accurate and objective diagnoses. A fluorescence-based diagnosis tool through headlights combined with special-filtered dental loupes may serve as a hands-free solution for both precise diagnosis and effective removal of plaque-biofilms.

Patient aggression toward dentists.

BACKGROUND: Workplace violence toward health care professionals is both widespread and widely overlooked. Only 4 studies of aggression toward dentists have been published-none in the United States-with the prevalence of aggression ranging from 29% through 80%. The purpose of this study was to provide an initial estimate of rates of patient aggression in dental practices in the United States. METHODS: The authors surveyed 98 dentists recruited from the faculty and alumni network of a college of dentistry. Participants completed a confidential online survey assessing whether they had experienced any of 21 specific types of aggressive behaviors from their patients. RESULTS: Past-year aggression prevalence was 22.2%, 55.0%, and 44.4% for physical, verbal, and reputational aggression, respectively. Career prevalence was 45.5%, 74.0%, and 68.7% for physical, verbal, and reputational aggression, respectively. Rates did not differ by sex, race, ethnicity, specialty, age, years practicing, or average number of patients treated per day. CONCLUSIONS: Participants reported levels of physical, verbal, and reputational aggression at rates comparable with those of other health care professionals in the United States and abroad. Additional research with larger representative samples of dentists in the United States is necessary to confirm these prevalence estimates. Future research should also investigate predictors and outcomes of patient aggression and prevention and intervention strategies. PRACTICAL IMPLICATIONS: Substantial rates of patient aggression highlight the need to address this problem in dental practices. The authors discuss implications for the dental profession, including proactive steps that could be taken to reduce patient aggression in dental offices.

Patient aggression toward dental students.

Aggression from patients is one of the risks faced by healthcare workers during a typical work week. This risk begins during training. Although rates of patient aggression have been estimated for nursing students and medical residents, studies of aggression toward dental students have not been conducted. To begin to address this knowledge gap, we surveyed 160 D.D.S. student dentists in their third- or fourth years who were attending a large urban college of dentistry during the 2018-2019 academic year. Each class had approximately 375 students, leading to a response rate of 21%. Approximately 28% of students reported experiencing at least 1 instance of physical aggression, 86% reported experiencing at least 1 instance of verbal aggression, and 36% reported experiencing at least 1 instance of reputational aggression. There were no differences in rates of experienced aggression by age or gender, but Hispanic or Latinx students were more likely to experience physical and reputational aggression than non-Hispanic White or Asian students. We discuss implications for dental education, including modifications to training clinic procedures and curriculum additions or modifications that may help prepare students to prevent and address patient aggression within the dental clinic environment.

Evidence-based clinical practice guideline on nonrestorative treatments for carious lesions: A report from the American Dental Association.

BACKGROUND: An expert panel convened by the American Dental Association Council on Scientific Affairs and the Center for Evidence-Based Dentistry conducted a systematic review and formulated evidence-based clinical recommendations for the arrest or reversal of noncavitated and cavitated dental caries using nonrestorative treatments in children and adults. TYPES OF STUDIES REVIEWED: The authors conducted a systematic search of the literature in MEDLINE and Embase via Ovid, Cochrane CENTRAL, and Cochrane database of systematic reviews to identify randomized controlled trials reporting on nonrestorative treatments for noncavitated and cavitated carious lesions. The authors used the Grading of Recommendations Assessment, Development and Evaluation approach to assess the certainty in the evidence and move from the evidence to the decisions. RESULTS: The expert panel formulated 11 clinical recommendations, each specific to lesion type, tooth surface, and dentition. Of the most effective interventions, the panel provided recommendations for the use of 38% silver diamine fluoride, sealants, 5% sodium fluoride varnish, 1.23% acidulated phosphate fluoride gel, and 5,000 parts per million fluoride (1.1% sodium fluoride) toothpaste or gel, among others. The panel also provided a recommendation against the use of 10% casein phosphopeptide-amorphous calcium phosphate. CONCLUSIONS AND PRACTICAL IMPLICATIONS: Although the recommended interventions are often used for caries prevention, or in conjunction with restorative treatment options, these approaches have shown to be effective in arresting or reversing carious lesions. Clinicians are encouraged to prioritize use of these interventions based on effectiveness, safety, and feasibility.

Dentists: Critical aspects of their own and their community's disaster preparedness plan.

The weather-related disasters in 2017 in Texas, Florida, Puerto Rico, the 2017-2018 wildfire seasons in California and Hurricanes Florence and Michael in 2018 have challenged all healthcare professionals, to have plans in place to protect their facility, patients, and staff from all possible hazards. These were "slowly developing" events, with enormous media coverage, and yet the results were still horrific. The need to have both a good evacuation plan and a good shelter-in-place plan has previously been dramatically demonstrated. When planning for disasters, it is critical for healthcare providers to understand the nature of a particular event and its possible consequences. When the concern arises about either an individual medical facility, or a whole community's well-being, a proper response requires significant levels of preparedness, education, and training. Comprehension of the threat and an understanding of the resources available to combat an event can significantly mitigate the possible damage. This article reviews a dental school curriculum to prepare students to respond to such contingencies while describing the goals, and sources for a disaster preparedness syllabus.

"You Get Beautiful Teeth Down There": Racial/Ethnic Minority Older Adults' Perspectives on Care at Dental School Clinics.

To help eliminate reported racial/ethnic and socioeconomic inequities in oral health care, listening to the perspectives of racial/ethnic minority older adults on their experiences with dental school clinics is needed. The aim of this study was to examine the experiences of African American, Puerto Rican, and Dominican older adults who attend senior centers in upper Manhattan, New York City, regarding the care received at dental school clinics. Focus groups were conducted from 2013 to 2015 with 194 racial/ethnic minority men and women aged 50 years and older living in upper Manhattan. All of the 24 focus group sessions were digitally audiorecorded and transcribed for analysis. Groups conducted in Spanish were transcribed first in Spanish and then translated into English. Analysis of the transcripts was conducted using thematic content analysis. Seven subthemes were manifest in the data related to these adults' positive experiences with dental school clinics: excellent outcomes and dentists, painless and safe treatment, affordable care, honest and reputable, benefits of student training, accepting and helpful, and recommended by family and friends. Negative experiences centered around four subthemes: multiple visits required for treatment, loss of interpersonal communication due to use of technology, inconvenient location, and perceived stigma with Medicaid. This study provided novel evidence of the largely positive experiences with dental schools of racial/ethnic minority senior center attendees. Interventions targeted at the organization and provider level, including organizational motivation, resources, staff attributes, climate, and teamwork plus payment programs and services, insurance and affordability, and provider- and system-level supports, may improve health care processes and patient experiences of care.

Dental Fear and Avoidance in Treatment Seekers at a Large, Urban Dental Clinic.

PURPOSE: The prevalence and correlates of dental fear have been studied in representative population studies, but not in patients presenting for dental treatment. We hypothesized that dental fear among patients presenting at a large, urban college of dentistry would be similar to that of the population (e.g. 11% high dental fear, 17% to 35% moderate or higher fear) and that fear would be associated with avoidance of routine dental care, increased use of urgent dental care and poor oral health. MATERIALS AND METHODS: Participants were 1070 consecutive patients at a large, urban dental care center. All patients completed a clinical interview, including demographics, medical history, dental history and presenting concerns, and behavioral health history. Patients were also asked to rate their dental anxiety/fear on a 1 (none) to 10 (high) scale. RESULTS: Over 20% of patients reported elevated anxiety/fear, of which 12.30% reported moderate and 8.75% high fear. Severity of dental anxiety/fear was strongly related to the likelihood of avoiding dental services in the past and related to myriad presenting problems. CONCLUSIONS: As hypothesized, the prevalence of moderate or higher fear in dental patients was considerable and closely matched that found in general population surveys. Thus, the 'dental home' is an ideal location to treat clinically significant dental anxiety/fear.

A pilot study of dentists' assessment of caries detection and staging systems applied to early caries: PEARL Network findings.

The International Caries Detection and Assessment System (ICDAS II) and the Caries Classification System (CCS) are caries stage description systems proposed for adoption into clinical practice. This pilot study investigated clinicians' training in and use of these systems for detection of early caries and recommendations for individual tooth treatment. Patient participants (N = 8) with a range of noncavitated lesions (CCS ranks 2 and 4 and ICDAS II ranks 2-4) identified by a team of calibrated examiners were recruited from the New York University College of Dentistry clinic. Eighteen dentists-8 from the Practitioners Engaged in Applied Research and Learning (PEARL) Network and 10 recruited from the Academy of General Dentistry-were randomly assigned to 1 of 3 groups: 5 dentists used only visual-tactile (VT) examination, 7 were trained in the ICDAS II, and 6 were trained in the CCS. Lesion stage for each tooth was determined by the ICDAS II and CCS groups, and recommended treatment was decided by all groups. Teeth were assessed both with and without radiographs. Caries was detected in 92.7% (95% CI, 88%-96%) of the teeth by dentists with CCS training, 88.8% (95% CI, 84%-92%) of the teeth by those with ICDAS II training, and 62.3% (95% CI, 55%-69%) of teeth by the VT group. Web-based training was acceptable to all dentists in the CCS group (6 of 6) but fewer of the dentists in the ICDAS II group (5 of 7). The modified CCS translated clinically to more accurate caries detection, particularly compared to detection by untrained dentists (VT group). Moreover, the CCS was more accepted than was the ICDAS II, but dentists in both groups were open to the application of these systems. Agreement on caries staging requires additional training prior to a larger validation study.

Experimental and finite element study of residual thermal stresses in veneered Y-TZP structures.

The main complications of zirconia-based laminated systems are chipping and delamination of veneering porcelain, which has been found to be directly associated with the development of residual thermal stresses in the porcelain layer. This study investigates the effects of cooling rate and specimen geometry on the residual stress states in porcelain-veneered zirconia structures. Bilayers of three different shapes (bars, semi-cylindrical shells, and arch-cubic structures) with 1.5 mm and 0.7 mm thickness of dentin porcelain and zirconia framework, respectively, were subjected to two cooling protocols: slow cooling (SC) at 32 °C/min and extremely-slow cooling (XSC) at 2 °C/min. The residual thermal stresses were determined using the Vickers indentation method and validated by finite element analysis. The residual stress profiles were similar among geometries in the same cooling protocol. XSC groups presented significantly higher tensile stresses (p = 0.000), especially for curved interfaces. XSC is a time-consuming process that showed no beneficial effect regarding residual stresses compared to the manufacturer recommended slow cooling rate.