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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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Background Regular good denture hygiene by individuals with removable partial dentures (RPDs) is an important component of oral health and in the prevention of further dental problems. These individuals should be provided with advice on the importance of denture care and be aware of this information.Aim To establish deficiencies in patient knowledge surrounding denture hygiene by RPD wearers.Methodology The study was undertaken as an audit. Data was collected from April 2012 to October 2012 via a questionnaire completed by 196 RPD wearers attending as patients at the University Dental Hospital Wales and the dental units at St David’s Hospital and Cynon Valley Hospital. The audit criterion was patients with RPDs should have knowledge of denture hygiene, with the standard set at 100%.Results While 91.8% of participants stated they were provided with instructions on denture hygiene when provided with their current prosthesis, 60.2% were shown to have less than an appropriate level of denture cleanliness, with 9.2% reporting that they slept wearing their prosthesis.Conclusion The audit criterion and standard set were not achieved. A lack of knowledge surrounding denture hygiene was demonstrated among participants. As a part of the audit process the health education of RPD wearers' hygiene needs to be improved and awareness levels of the whole dental team needs to be raised. All partial dentures should receive information and regular reinforcement of key dental hygiene messages.

Concepts: Health, Patient, Prosthesis, Oral hygiene, Dentures, Restorative dentistry, Removable partial denture, Prosthodontology

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This final article in a series of three on producing complete dentures which the patient considers attractive, describes selecting the denture teeth, setting the front teeth at the chairside, the try-in visits, processing, fitting and reviewing the dentures. The role of the patient as captain of the ship, the dental nurse as the patient’s support and liaison officer, and the clinician as the first technical officer is outlined. The use of immediate replay video technology in allowing a patient to see what the trial denture really looks like is described. It is vital that the patient is completely happy with its appearance in every detail before any denture is finished. Dealing with post-fitting aesthetic problems is considered.

Concepts: Teeth, Oral hygiene, Dentures, Human physical appearance, Sexual attraction, Prosthodontology, Prosthodontics, Denturist

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Even dentures exhibiting superb aesthetics are of no use if they visibly move during speech and social intercourse. In this, the second paper of three on removable denture aesthetics, we describe impression making and shaping the wax occlusal record rims. Not only are the impressions important for producing dentures with maximum retention, stability and support, but their extensions and the thickness of their borders have a decisive influence on lip support and profile. This article shows how the contours of the definitive impressions and the wax rims are developed so as to prescribe the overall form of the replacement gums and teeth. Properly trimmed rims are in essence an early three-dimensional rehearsal, an opportunity for developing the patient’s preferred lip support and natural positioning of the denture teeth at subsequent stages. They can also give an early indication of what speech will be like with the new dentures. Without this 3D clinical information, laboratory technicians have to guess where to put the teeth and have little option but to fall back on the stereotypes of their textbook training.

Concepts: Practice, Teeth, Oral hygiene, Dentures, Prosthodontology, Prosthodontics, The Temptations, The Impressions

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The aim of this study was to compare the perceived competence for treating prosthodontic patients of two samples of fourth-year dental students: those educated using traditional methodologies and those educated using problem-based learning (PBL). Two cohorts of fourth-year dental students at a dental school in Spain were surveyed: the traditional methods cohort (n=46) was comprised of all students in academic years 2012 and 2013, and the PBL cohort (n=57) was comprised of all students in academic years 2014 and 2015. Students in both cohorts reported the number of prosthodontic treatments they carried out per year and their perceived level of competence in performing such treatments. The results showed that the average number of treatments performed was similar for the two cohorts, except the number of metal-based removable partial dentures was significantly higher for students in the traditional (0.8±1.0) than the PBL (0.4±0.6) cohort. The level of perceived competence to treat complete denture patients for the combined cohorts was significantly higher (7.3±1.1) than that for partial acrylic dentures (6.7±1.5) and combined dentures (5.7±1.3). Students' clinical competence in prosthodontics mainly depended on number of treatments performed as the operator as well as the assistant. Students in the traditional methods cohort considered themselves to be significantly more competent at treating patients for removable partial and fixed prostheses (7.8±1.1 and 7.6±1.1, respectively) than did students in the PBL cohort (6.4±1.5 and 6.6±1.5, respectively). Overall, however, the study found that practical experiences were more important than the teaching method used to achieve students' perceived competence.

Concepts: Education, Dentures, Restorative dentistry, Removable partial denture, American Dental Association, Prosthodontology, Prosthodontics, Palatal obturator

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Data sourcesMedline/PubMed, Embase, BIOSIS/Ovid, SciSearch/DIMDI, Cochrane library, FIZ Technik Web and hand searches of the journals; Clinical Oral Investigations, International Journal of Prosthodontics, Journal of Prosthetic Dentistry, Deutsche Zahnärztliche Zeitschrift, Swiss Dental Journal, Journal of Dentistry and the Journal of Dental Research.Study selectionRandomised controlled trials, prospective and retrospective studies on survival rates of removable dental prostheses in the moderately reduced dentition with at least 15 participants having an observation period of at least two years, and a dropout rate of less than 25% were considered.Data extraction and synthesisTwo reviewers abstracted data. A qualitative summary of the included studies was carried out. Studies providing data that permitted a Kaplan-Meier analysis were included in meta-analysis.ResultsThe review included 19 studies, six of which were in multiple publications. Cast-metal framework dentures showed failure rates of 33% and 50% after five years. One study with a 25-year observation period reported failure rates of 50%. Proper pretreatment and a good recall scheme improve the results. Bilateral attachment prostheses showed failure rates of 11% and 30% after five years. Unilateral attachment prostheses showed failure rates of 75% after five years. Double-crown prostheses dentures show failure rates of 0% to 21.7% after three to six years.ConclusionsWithin the limitations of this study, it seems that removable partial dentures, (RPD), given suitable pretreatment and follow-up regimes, can provide a satisfactory treatment option. Based on only one paper, they revealed acceptable results even over a very long observation period (25 years).

Concepts: Prosthetics, Dental implant, Prosthesis, Dentures, Removable partial denture, Prosthodontology, Prosthodontics, Palatal obturator

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The purpose of this study was to evaluate whether the use of removable partial dentures affects the periodontal status of abutment teeth. An observational cross-sectional study was done on a sample of patients rehabilitated with removable partial dentures (2010 to 2013). At a recall appointment, a clinical examination was done to collect data related to the rehabilitation and periodontal status of the abutment teeth. Of 145 invited patients, 54 attended the requested follow-up appointment (37.2%). Mean patient age was 59.1 years, and the study population was 42.6% male and 57.4% female. The mean follow-up time for the prosthesis was 26 months. Abutment teeth had higher values in all periodontal variables (P < .001). Occlusal clasps had the worst results in relation to clasps with a gingival approach (P < .005). Significant differences were also found in mandibular abutment teeth of Kennedy Class I and II compared to Class III (P < .048). The periodontal status of the abutment teeth of removable partial dentures is affected by these rehabilitations. A recall program for these patients involving removable prosthodontics and periodontology appointments is mandatory.

Concepts: Sociology, Periodontology, Gingiva, Periodontitis, Dentures, Removable partial denture, Class III railroad, Prosthodontology