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Concept: Prosthodontology

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A patient exhibited severe abrasion of resin posterior denture teeth including perforation of the denture base. New dentures were provided to explore the application of zirconia teeth for complete dentures. [Correction added to online publication 07 November 2012: “Zirconium” corrected to “Zirconia”.] Traditional denture procedures were combined with fixed prosthodontic CAD/CAM procedures to fabricate custom-designed four-tooth posterior segments in hollow crown form to reduce weight and with a retentive form for interlocking to the denture base. The new dentures were successful in reducing wear of the denture teeth over the short-term follow-up period.

Concepts: Nitrogen, Teeth, Tooth enamel, Dentures, Zirconium dioxide, Prosthodontology, Prosthodontics

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If prosthodontic treatment is considered after periodontal therapy, the questions arise i) does prosthodontic treatment affect the treatment outcome of the dentition in general and ii) which type of prosthesis is related to best treatment outcome of abutment teeth? Our goal was to compare long-term tooth loss after comprehensive periodontal therapy in patients with or without prosthodontic treatment. Ninety patients' charts with a total of 1937 teeth who had received comprehensive periodontal treatment 5-17 years ago by the same periodontist were retrospectively evaluated. Sixty-five patients received fixed dental prostheses (FDP; n = 29) and/or removable partial dentures anchored with clips (RPDC; n = 25) or double crowns (RPDD; n = 25). Twenty-five patients were also periodontally compromised but treated without prosthodontic treatment and served as a control group. A total of 317 teeth and 70 abutment teeth were lost during 9·7 ± 4·1 years of observation. Thereof, 273 teeth and 48 abutment teeth were lost due to periodontal reasons. Mean tooth loss amounted to 1·2 ± 1·5 (controls) and 4·4 ± 3·4 (partial dentures). Abutment tooth loss was 0·4 ± 1·1 (FDP), 1·0 ± 1·2 (RPDC) and 1·3 ± 1·0 (RPDD). Poisson regressions identified prosthodontic treatment, age, socio-economic status, diabetes mellitus, mean initial bone loss and aggressive periodontitis as factors significantly contributing to tooth loss. Age, diabetes and non-compliance contributed to abutment tooth loss. Not considering biomechanical factors, patients with prosthodontic reconstructions under long-term supportive periodontal therapy were at higher risk for further tooth loss than patients without prostheses. Not only the type of partial denture but also the patient-related risk factors were associated with abutment tooth loss.

Concepts: Diabetes mellitus, Periodontology, Periodontitis, Prosthesis, Oral hygiene, Dentures, Removable partial denture, Prosthodontology

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In dental applications, precision attachments have been used to retain removable partial dentures (RPDs) for several decades. Various types of extracoronal attachments are commonly used in combination with fixed partial dentures and RPDs to achieve retention and stability. Fracture of the framework, fracture of the roots or teeth, and irretrievable decrease of retention are common reasons for a failed attachment-retained RPD. Another complication of metal ceramic crowns with precision attachment is decementation of the crowns. When fixed components of the attachment-retained RPD fail, the traditional treatment approach requires remaking both the fixed and removable components of the attachment-retained RPD. This technique describes retrofitting of a metal ceramic crown to a resilient attachment-retained RPD.

Concepts: The Roots, Crown, Oral hygiene, Dentures, Restorative dentistry, Removable partial denture, Prosthodontology, Precision attachment

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Preclinical dental students must demonstrate aptitude in the preparation of teeth for treatment with several types of fixed dental prostheses. The optimal sequence of instruction and examination of these crown preparations in preclinical fixed prosthodontics is unknown. The aim of this study was to determine if grading scores by faculty and students were affected by changing the sequence of crown type preparations. Practical exams of two successive student cohorts (n=89 in 2014; n=92 in 2015) at one U.S. dental school using three crown preparations (full cast, porcelain fused to metal, and all-ceramic) in different order were analyzed by faculty grades and student self-assessment. All of the models indicated that the sequence in which the crown type preparations were taught did have an effect on the grades. The 2014 cohort had overall higher grades and particularly higher grades for the all-ceramic crown preparations. Evaluation scores were affected by the sequence in which the different crown type preparations were taught and tested. Although the overall results suggested that students may perform better if the all-ceramic crown preparation is taught last, this tendency may differ between years.

Concepts: Crown, Dental restoration, Restorative dentistry, CAD/CAM Dentistry, Bridge, Prosthodontology, Inlays and onlays, Fixed prosthodontics

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The authors evaluated and quantified clinically detectable errors commonly seen in impressions sent to commercial laboratories and determined possible relationships between finish line errors and other factors involved.

Concepts: Gold, Crown, Dental restoration, Prosthodontology

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Crowns, fixed partial dentures, and removable dentures are the popular prosthetic dental restorations in current dental practice. Prosthodontic rehabilitation of the mouth, particularly in advanced and complex cases, requires careful planning, adequate clinical skills, and exacting technical standards. While a successful outcome is the ultimate goal for any prosthodontic treatment, complications, injuries, dissatisfaction, and/or failure may occur. When such events develop as a result of negligence or violation of standards of care, they are considered under the term of malpractice and may incur ethical and medico-legal implications. This paper reviews and highlights some aspects of malpractice in prosthodontics. The current state of prosthodontic malpractice on a global level will also be evaluated. Standards of prosthodontic care, current literature of prosthodontic malpractice, where and how prosthodontic malpractice occurs, and recommendations for the future are presented. A thorough understanding of what is quality prosthodontic care and what disrupts this care can be a useful guard against professional litigation and may protect patients from poor quality of dental prosthetic care.

Concepts: Dental implant, Dentures, American Dental Association, Prosthodontology, Prosthodontics, Dental technician, Palatal obturator, Fixed prosthodontics

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This study compared the acceptability and relative effectiveness of case-based learning (CBL) versus traditional lecture-based (LB) instruction in a preclinical removable prosthodontics course in the University of North Carolina at Chapel Hill School of Dentistry DDS curriculum. The entire second-year class (N=82) comprised this crossover study’s sample. Assessments of baseline comprehension and confidence in removable partial denture (RPD) treatment planning were conducted at the beginning of the course. Near the end of the course, half of the class received CBL and LB instruction in an RPD module in alternating sequence, with students serving as their own control group. Assessments of perceived RPD treatment planning efficacy, comprehension, and instruction method preference were administered directly after students completed the RPD module and six months later. Analyses of variance accounting for period, carryover, and sequence effects were used to determine the relative effects of each approach using a p<0.05 statistical significance threshold. The results showed that the students preferred CBL (81%) over LB instruction (9%), a pattern that remained unchanged after a six-month period. Despite notable period and carryover effects, CBL was also associated with higher gains in RPD treatment planning comprehension (p=0.04) and perceived efficacy (p=0.01) compared to LB instruction. These gains diminished six months after the course-a finding based on a 49% follow-up response rate. Overall, the students overwhelmingly preferred CBL to LB instruction, and the findings suggest small albeit measurable educational benefits associated with CBL. This study's findings support the introduction and further testing of CBL in the preclinical dental curriculum, in anticipation of possible future benefits evident during clinical training.

Concepts: Clinical trial, Crossover study, Effectiveness, Education, Statistical hypothesis testing, Dentures, Relative effectiveness factor, Prosthodontology

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Removable partial dentures (RPDs) are widely used to replace missing teeth in order to restore both function and aesthetics for the partially dentate patient. Conventional RPD design is frequently bilateral and consists of a major connector that bridges both sides of the arch. Some patients cannot and will not tolerate such an extensive appliance. For these patients, bridgework may not be a predictable option and it is not always possible to provide implant-retained restorations. This article presents unilateral RPDs as a potential treatment modality for such patients and explores indications and contraindications for their use, including factors relating to patient history, clinical presentation and patient wishes. Through case examples, design, material and fabrication considerations will be discussed. While their use is not widespread, there are a number of patients who benefit from the provision of unilateral RPDs. They are a useful treatment to have in the clinician’s armamentarium, but a highly-skilled dental team and a specific patient presentation is required in order for them to be a reasonable and predictable prosthetic option.

Concepts: Medical terms, Patient, Hospital, Dentures, Restorative dentistry, Removable partial denture, Prosthodontology, St. Louis, Missouri

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Preclinical fixed prosthodontics is taught by Department of Prosthodontics faculty members at Virginia Commonwealth University School of Dentistry; however, 86% of all clinical cases in academic year 2012 were staffed by faculty members from the Department of General Practice. The aims of this retrospective study were to quantify the quality of impressions, accuracy of laboratory work authorizations, and most common errors and to determine if there were differences between the rate of errors in cases supervised by the prosthodontists and the general dentists. A total of 346 Fixed Prosthodontic Laboratory Tracking Sheets for the 2012 academic year were reviewed. The results showed that, overall, 73% of submitted impressions were acceptable at initial evaluation, 16% had to be poured first and re-evaluated for quality prior to pindexing, 7% had multiple impressions submitted for transfer dies, and 4% were rejected for poor quality. There were higher acceptance rates for impressions and work authorizations for cases staffed by prosthodontists than by general dentists, but the differences were not statistically significant (p=0.0584 and p=0.0666, respectively). Regarding the work authorizations, 43% overall did not provide sufficient information or had technical errors that delayed prosthesis fabrication. The most common errors were incorrect mountings, absence of solid casts, inadequate description of margins for porcelain fused to metal crowns, inaccurate die trimming, and margin marking. The percentages of errors in cases supervised by general dentists and prosthodontists were similar for 17 of the 18 types of errors identified; only for margin description was the percentage of errors statistically significantly higher for general dentist-supervised than prosthodontist-supervised cases. These results highlighted the ongoing need for faculty development and calibration to ensure students receive the highest quality education from all faculty members teaching fixed prosthodontics.

Concepts: University, Dentistry, Dentures, Prosthodontology, Prosthodontics, Palatal obturator, Fixed prosthodontics, Virginia Commonwealth University

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The aim of this retrospective study was to quantify differences between general dentists and prosthodontists regarding appointments, treatment time, impressions, and preoperative diagnostic data in teaching predoctoral clinical fixed prosthodontics. Electronic dental records (n=356) of patients treated at one dental school in academic year 2012 were randomly selected for review to obtain the following data: faculty and student demographics, number of appointments and treatment time from preparation to cementation, number of impressions made, completion of oral disease control treatment (ODCT), and presence of preoperative periapical radiographs and diagnostic casts. The results showed that ODCT was completed in 78%, preoperative radiographs were present in 76%, and diagnostic casts made in 53% of the cases reviewed. There was no statistically significant difference in number of appointments, treatment time, or number of final impressions when students were staffed by general dentists or prosthodontists. When students were supervised by multiple faculty members, there was generally an increase in treatment time and number of appointments and final impressions. Although this study found no statistically significant differences between general dentists and prosthodontists regarding the criteria evaluated, the results suggest that faculty development and calibration are needed to ensure ODCT is completed and preoperative radiographs are present prior to initiating fixed prosthodontic procedures.

Concepts: Statistics, Statistical significance, University, Dentistry, American Dental Association, Prosthodontology, Prosthodontics, Fixed prosthodontics