Milled PMMA, a Material for Long-Term Implant Supported Fixed Complete Dental Prostheses.

Traditionally, metal-ceramics, metal-reinforced acrylics, and more recently full-contour or layered zirconia have been the materials of choice for definitive fixed implant-supported rehabilitations. Polymethyl Methacrylate (PMMA) is commonly used in implant dentistry for the fabrication of implant-supported interim prostheses and as milled or 3D printed prototypes. This article describes a novel protocol to prosthetically restore a completely edentulous patient following a digital workflow, with fixed, screw-retained, implant-supported prostheses fabricated from CAD/CAM milled polymethyl methacrylate (PMMA), with no metal substructure. After two years follow up in terms of esthetics, phonetics, function and biological tissue response, the outcome remains functional and free of mechanical, biomechanical or biological complications. The aim of this article is to illustrate the feasibility of using milled PMMA as viable definitive prosthetic material for the fixed implant rehabilitation of edentulous patients.

Importance of bitewing radiographs for the early detection of interproximal carious lesions and the impact on healthcare expenditure in Japan.

BACKGROUND: Globally, the direct cost of dental caries is approximately $298B yearly, consuming 5-10% of national healthcare budgets. Bitewing radiographs (BWR) are the standard method of diagnosing interproximal dental caries. In Japan, bitewing radiographs are rarely used. This retrospective observational study was conducted to measure the potential economic impact of carious lesions left undiagnosed and untreated due to this omission of bitewing radiographs. METHODS: The total number of existing carious lesions, the number of undiagnosed lesions, and costs of treating these lesions were calculated from the national database of Ministry of Health, Labor and Wellness in Japan between June 2013 and 2017. The number of affected teeth was estimated using prevalence data and undiagnosed lesions were estimated. The expense associated with treating progressed lesions was calculated using the standard Japanese fee structure. BWR trends were assessed, and analyses were performed to understand the differences between states and populations over time. RESULTS: The average number of BWR taken monthly per office was 48.3±1.1 (average ± SD). It was calculated that an average of 6,429,155 lesions went undiagnosed per month, 93.5 teeth per practice, and 1.6 teeth per patient. The cost of treating lesions that went undiagnosed and then progressed into more invasive restorations was estimated to be between $57M-$218M more (difference between NaF varnish and class II restorations), and $150M-$443M more (difference between Class II restoration and crown or crown with RCT). CONCLUSIONS: BWRs are crucial in diagnosing a significant number of carious lesions. There is considerable impact on health and cost to the national health system due to undiagnosed lesions. Practitioners need to be educated on reading and understanding BWR, and policy should be changed to cover BWR.

Admissions data as predictors for student performance in restorative dentistry.

INTRODUCTION: The purpose of the study was to determine the relative predictive power of admissions criteria and predoctoral academic performance in the area of restorative dentistry in order to better understand and guide the dental school admissions process. METHODS: In addition to admissions criteria, student performance in restorative dentistry, such as the Final Restorative Treatment course, the didactic and preclinical examinations, and the objective structured clinical examinations (OSCE), was measured for the 172 predoctoral students representing the graduating classes of 2017-2021. RESULTS: The association between the didactic score in restorative dentistry and grade point average (GPA, p = 0.009) and Dental Admission Test (DAT, p = 0.002) score was statistically significant. Although no statistically significant association was found between preclinical scores and gender, GPA, or DAT, there was a statistically significant association between preclinical scores and the Perceptual Ability Test (PAT) score (p = 0.012). Preclinical scores included laboratory examinations for fixed prosthodontics, such as crown preparation and temporization, representing hand skills assessment. Finally, there was no statistically significant association found between the OSCE score and any of the admissions criteria. CONCLUSION: The dental admissions criteria could play a role in predicting academic performance in the didactic portion and preclinical component of restorative dentistry.

Predoctoral Student Performance in a Restorative Dentistry Course During the COVID-19 Pandemic.

PURPOSE: To compare predoctoral student performance in restorative dentistry related to curricular changes implemented in response to the COVID-19 pandemic and to evaluate the impact of remote education on performance in didactic and preclinical examinations and objective structured clinical examinations (OSCEs). MATERIALS AND METHODS: The study population consisted of 172 students, all members of the DMD graduating classes from 2017 to 2021. Scores in the Final Restorative Treatment (FRTx) course, subdivided into didactic and preclinical lab work, and the OSCEs were assessed and compared between pre-pandemic students and during-pandemic students. RESULTS: Performance in the preclinical lab exercises was statistically significantly higher in the during-pandemic cohort than in the pre-pandemic cohort after adjusting for students' gender and admission scores. Performance in restorative dentistry as measured by the OSCE was not statistically different among during-pandemic students compared to the pre-pandemic students. It was observed that students were more efficient and engaged during the more limited lab sessions with the increased student-to-faculty ratio that allowed for more feedback. CONCLUSION: Although virtual education cannot replace in-person experiences, this model served students satisfactorily during the COVID-19 pandemic, with added support structures such as flexible scheduling, interactive sessions, and additional small-group discussions to maintain academic performance in predoctoral education.

An In Vivo Spectrophotometric Analysis of Gingival Acrylic Shade Guide.

Selecting shades of acrylic gingival restorative material is challenging. This study examined the shade appropriateness of five acrylic gingival restorative materials. The color was analyzed using an intraoral spectrophotometer (Crystaleye®, Olympus). The gingival color of maxillary incisors for eighty-nine patients was measured. CIELAB color coordinates (L*, a* and b*) were obtained, and the color difference ∆E (Coverage Error: CE) between shade tabs and natural gingival color of patient samples for each shade guide system were compared. Repeated ANOVA and post hoc analyses with Tukey's HSD were performed. There was a significant difference among the mean minimum CEs of the tab sets (p < 0.01). GC Acrylic (CE = 5.89 ∆E ± 2.97) and Lucitone 199® (CE = 6.55 ± 3.33) groups exhibited CEs significantly lower than all other groups (all p < 0.001). The IvoCap® system exhibited the highest CE (10.78 ± 3.80), significantly greater than all other groups (p < 0.001). No significant differences were observed based on sex (p = 0.055) or ethnicity (p = 0.327). The GC Acrylic and Lucitone 199® shade guides showed the lowest CEs. All guides had coverage errors above 5.89 ∆E, which is larger than ∆E thresholds of acceptability. Of the materials evaluated in this study, GC Acrylic and Lucitione 199® are best able to reproduce the clinical appearance of the gingival tissue. Many patients have tissue that cannot be reproduced accurately with currently available materials.

A novel technique for guided bone regeneration using platelet-rich plasma and osteogenic progenitor cells: Literature-based rationale and case report.

Achieving predictable guided bone regeneration in critical size defects for future endosseous dental implant therapy poses a great challenge to clinicians. A novel technique utilizing autogenous osteogenic progenitor cells, calcium sulfate activated platelet-rich plasma in addition to particulate allograft was successfully used to augment a severely deficient maxillary anterior edentulous ridge. After 6 months of healing, satisfactory radiographic and clinical bone gain was noted with significant increase in alveolar ridge width. Endosseous implants were placed and restored successfully. The techniques with underlying clinical and biologic rationales are presented and discussed in this report.