Determination of Caries Lesion Activity: Reflection and Roughness for Characterization of Caries Progression

Used by permission. © Operative Dentistry, Inc. Transmission or reproduction of protected items beyond that allowed by fair use requires the written permission of Operative Dentistry, Inc.Caries lesion progression is difficult to determine with visual and tactile examinations. The hypothesis of this study was that reflection and roughness measurements could determine caries progression. Ground/polished sound human enamel specimens were analyzed at baseline (sound) and after two four-day demineralization periods for reflection using optical reflectometry (ORef) and for roughness using optical surface profilometry (SPro). Specimens were demineralized using a microbial–Streptococcus mutans aries model. Comparisons among the periods for ORef and SPro were performed using repeated measures analysis of variance. Two-sample t-tests were used for differences in transverse microradiography. The integrated mineral loss and depth of the four-day demineralization period were significantly smaller than those for the eight-day demineralization period (p<0.01). With increased demineralization time, reflection was significantly decreased and roughness was significantly increased (p<0.01). Correlation between ORef and SPro was moderate (r=−0.63). Both reflection and roughness can be characterized for nondestructive longitudinal assessment of caries lesion progression

The roles of wedging and friction in the mechanics of dental occlusal contacts

Objective: The primary aim of this project is to elucidate the basic mechanical engineering principles that govern and explain unexpected and counter-intuitive occlusal contact force measurements. Methods: Forces were measured on matched pairs of first molar denture, ceramic and stainless steel crowns during occlusion and disclusion, with human saliva and dry (control). The weighted maxillary assembly, guided by a precision slide, was lowered onto, and raised from, the mandibular crown. The forces experienced by the mandibular tooth were continuously measured by the load cell that supported it. Statistical analyses included LOESS smoothing splines and generalized additive models. Principles of basic statics and classic friction were applied to explain and validate the results. Results: It was determined that within the span of a single chomp, the in-occlusal plane force component (Flateral) on the tooth is highly variable in direction and/or magnitude. The most salient observations were that Flateral was higher in disclusion than in occlusion, and the largest Flateral did not necessarily occur when the bite force was maximum. Furthermore, saliva significantly affected the results. Conclusions: The results demonstrated that contacting teeth experience complex transient mechanical environments that can be readily explained with elementary engineering principles involving wedging and friction at the occlusal contacts

Comparative Effectiveness of Structural versus Regulatory Protein Gene Transfer on Articular Chondrocyte Matrix Gene Expression

OBJECTIVE: The production of extracellular matrix is a necessary component of articular cartilage repair. Gene transfer is a promising method to improve matrix biosynthesis by articular chondrocytes. Gene transfer may employ transgenes encoding regulatory factors that stimulate the production of matrix proteins, or may employ transgenes that encode the proteins themselves. The objective of this study was to determine which of these 2 approaches would be the better choice for further development. We compared these 2 approaches using the transgenes encoding the structural matrix proteins, aggrecan or type II collagen, and the transgene encoding the anabolic factor, insulin-like growth factor I (IGF-I). METHODS: We transfected adult bovine articular chondrocytes with constructs encoding type II collagen, aggrecan, or IGF-I, and measured the expression of type II collagen ( COL2A1) and aggrecan ( ACAN) from their native genes and from their transgenes. RESULTS: IGF-I gene ( IGF1) transfer increased the expression of the native chondrocyte COL2A1 and ACAN genes 2.4 and 2.9 times control, respectively. COL2A1 gene transfer did not significantly increase COL2A1 transcripts, even when the transgene included the genomic COL2A1 regulatory sequences stimulated by chondrogenic growth factors. In contrast, ACAN gene transfer increased ACAN transcripts up to 3.4 times control levels. IGF1, but not ACAN, gene transfer increased aggrecan protein production. CONCLUSION: Taken together, these results suggest that the type II collagen and aggrecan production required for articular cartilage repair will be more effectively achieved by genes that encode anabolic regulatory factors than by genes that encode the matrix molecules themselves

In Vitro Performance of Near Infrared Light Transillumination at 780-nm and Digital Radiography for Detection of Non-Cavitated Approximal Caries

Objectives To evaluate the ability of a Near Infrared Light Transillumination (NILT) device to detect non-cavitated approximal caries lesions; and to compare its performance to Digital Radiography (DR). Methods Thirty human extracted premolars (sound to lesions into the outer one-third of dentin) were selected. Lesion depth was confirmed by micro-computed tomography (μ-CT). Teeth were mounted in a custom-made device to simulate approximal contact. DR and NILT (CariVu™, DEXIS, LLC, Hatfield, PA, USA) examinations were performed and repeated by three trained and calibrated examiners. Sensitivity, specificity, area under ROC curve (Az), inter- and intra-class correlation coefficients (ICCs) for each method, and correlation among the methods were determined. Results ICCs for intra-/inter-examiner agreement were substantial for NILT (0.69/0.64), and moderate for DR (0.52/0.48). Sensitivity/specificity for NILT and DR were 0.68/0.93 and 0.50/0.64, respectively. Az for NILT was 0.81, while for DR it was 0.61. Spearman correlation coefficient with μ-CT for NILT (0.65, p<0.001) demonstrated moderate association, while that of DR suggested no association (0.19, p = 0.289). Conclusion Within the limitations of this in vitro study, NILT demonstrated a potential for early approximal caries detection. NILT and DR performed the same regarding the accuracy for non-cavitated approximal caries detection; however, NILT was superior to DR in terms of repeatability, agreement and correlation with μ-CT

Predictive Validity of a Caries Risk Assessment Model at a Dental School

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153638/1/jddjde019017.pd

Assessment of the Calibration of Periodontal Diagnosis and Treatment Planning Among Dental Students at Three Dental Schools

Calibration in diagnosis and treatment planning is difficult to achieve due to variations that exist in clinical interpretation. To determine if dental faculty members are consistent in teaching how to diagnose and treat periodontal disease, variations among dental students can be evaluated. A previous study reported high variability in diagnoses and treatment plans of periodontal cases at Indiana University School of Dentistry. This study aimed to build on that one by extending the research to two additional schools: Marquette University School of Dentistry and West Virginia University School of Dentistry. Diagnosis and treatment planning by 40 third- and fourth-year dental students were assessed at each of the schools. Students were asked to select the diagnosis and treatment plans on a questionnaire pertaining to 11 cases. Their responses were compared using chi-square tests, and multirater kappa statistics were used to assess agreement between classes and between schools. Logistic regression models were used to evaluate the effects of school, class year, prior experience, and GPA/class rank on correct responses. One case had a statistically significant difference in responses between third- and fourth-year dental students. Kappas for school agreement and class agreement were low. The students from Indiana University had higher diagnosis and treatment agreements than the Marquette University students, and the Marquette students fared better than the West Virginia University students. This study can help restructure future periodontal courses for a better understanding of periodontal diagnosis and treatment planning

Assessing the Medical Emergency Preparedness of Dental Faculty, Residents, and Practicing Periodontists: An Exploratory Study

With the increased number of elderly and medically compromised individuals receiving dental care and the presence of systemic comorbidities and associated treatment modalities in this patient population, it is imperative that dentists be prepared to manage a variety of medical emergencies. The aim of this study was to assess the knowledge of and preparedness to manage common medical emergencies of cohorts of practicing periodontists, specialty residents, and faculty members, both for comparative purposes and as an aid to refining a dental school’s standardized case scenarios. The study, conducted in 2017, was designed for four groups of randomly selected participants with at least 20 in each group; the actual number of voluntary participants was 28 private practice periodontists, 22 residents in specialty programs, 21 specialist faculty members, and 24 general practice faculty members. Participants were asked to evaluate ten clinical emergency cases and identify the diagnosis and indicated intervention for each. Groups were also evaluated for differences among correct responses for each case. Overall, there were no statistically significant differences for number of correct diagnoses or interventions among the four groups. However, several cases had varying degrees of incorrect diagnoses and management across all groups. Participants who had recently graduated or were still in school were able to treat cases appropriately more often than the other participants. Further refinement of cases to assess provider preparedness to correctly diagnose and manage medical emergencies is needed, specifically establishing case-specific features and addressing areas of potential confusion before the cases are used for educational purposes

Role of Hemin and Growth Media on the Autofluorescence of Streptococcus mutans

poster abstractAbstract Carious lesions fluoresce under blue light. The primary cariogenic bacterium Streptococcus mutans has been shown previously to fluoresce within blue light wavelengths. In this study we wanted to determine the role of hemin and various growth media on the fluorescing properties of S. mutans under planktonic (total biomass) and biofilm (biofilm mass) growth conditions. UA159 was grown for 24 h at 37ºC in Tryptic Soy Broth (TSB), Brain Heart Infusion (BHI) and Todd Hewitt broth (THB) with and without hemin in 5% CO2. Biofilm was grown for 24 h in a 96 well sterile microplate in the above described media with and without hemin. A stock solution of Protoporphyrin –IX was prepared and diluted to concentrations ranging from 1.6-3.1×10-4 g/ml. A SpectraMax (M3) was used to determine the fluorescence from UA159. RFU of total biomass and biofilm mass was assessed by exciting at fixed wavelengths of 385 and 405 nm at a spectral band width of 10 nm. Emission spectra at 770 nm were observed with 385 nm and an emission of 800 and 810 nm with 405 nm. ANOVA on the ranks of the measurements was used, with four different factors including wavelength (770, 800 and 810 nm); total biomass or biofilm mass; various growth media (TSB, BHI, THB) and the presence/absence of hemin and interactions among the factors. The analysis allowed each media-hemin combination to have different variances. Hemin decreased the amount of fluorescence; regardless of the levels of the other factors (p≤0.0001). Without hemin, BHI had more fluorescence than THB (p≤0.0003) and TSB (p≤0.0001). However with hemin, THB had more fluorescence than BHI (p≤0.0001) and TSB (p≤0.0001). The role of hemin and porphyrin-related compounds in the metabolism of S. mutans should be elucidated

The effects of salivas on occlusal forces

Contacting surfaces of opposing teeth produce friction that, when altered, changes the contact force direction and/or magnitude. As friction can be influenced by several factors, including lubrication and the contacting materials, the aim of this study was to measure the occlusal load alterations experienced by teeth with the introduction of different salivas and dental restorative materials. Pairs of molar teeth were set into occlusion with a weighted maxillary tooth mounted onto a vertical sliding assembly and the mandibular tooth supported by a load cell. The load components on the mandibular tooth were measured with three opposing pairs of dental restorative materials (plastic denture, all-ceramic and stainless steel), four (human and three artificial) salivas and 16 occlusal configurations. All lateral force component measurements were significantly different (P < 0·0001) from the dry (control) surface regardless of the crown material or occlusal configuration, while the effects of the artificial salivas compared to each other and to human saliva depended on the crown material

Adenoma Detection Rate in Asymptomatic Patients with Positive Fecal Immunochemical Tests

Background and Aims The adenoma detection rate (ADR) is a powerful measure of screening colonoscopy quality. Patients who undergo colonoscopy for the evaluation of a positive fecal immunochemical test (FIT) have increased prevalence of colorectal neoplasia, but it is not known whether separate quality benchmarks are required. The aim of this study was to compare the conventional ADR to the ADR of colonoscopies performed for the evaluation of positive FIT, in asymptomatic average-risk patients. Methods Patients ≥ 50 years old who underwent colonoscopy for the evaluation of a positive FIT between January 1, 2013, and July 31, 2014, at a tertiary Veterans Affairs Medical Center were identified. FIT performed for any indication other than average-risk screening was excluded. The comparison group included average-risk patients ≥ 50 years old undergoing screening colonoscopy during the same time frame. The two groups were compared for ADR, advanced neoplasm [adenoma ≥ 10 mm, tubulovillous, high-grade dysplasia, CRC, sessile serrated polyp (SSP) ≥ 10 mm], CRC, and SSP detection after propensity score adjustment using a logistic regression model adjusted for endoscopist. Results There were 207 patients in the FIT group and 601 in the screening colonoscopy comparison group. After propensity score adjustment, ADR (72.9 vs. 50.0%, p = 0.003), number of adenomas per colonoscopy (3.3 ± 3.6 vs. 1.4 ± 2.3, p = 0.033), and advanced neoplasm detection rate (32.4 vs. 11.0%, p < 0.0001) were significantly higher in the FIT group. There were no significant differences in the number of CRC and the SSP detection rate. Conclusions In this cohort of average-risk Veterans, the ADR of colonoscopies performed for the evaluation of a positive FIT was higher than the ADR of screening colonoscopies. Patients with a positive FIT also had significantly more adenomas per colonoscopy and advanced neoplasms. These findings suggest that the quality of colonoscopies performed for a positive FIT is insufficiently assessed by the conventional ADR and requires additional quality metrics