Fabrication of a removable partial denture of injectable poly (ether-ether-ketone) (PEEK) made partially by a digital workflow: case report

The introduction of computer-aided design and computer-aided manufacturing in rehabilitation with removable partial denture, enabled the emergence of new methods of fabrication of the framework and materials. In view of this, polyether-ether-ketone appears as an alternative to Cobalt-Chromium, due to its aesthetic properties, high resistance and for being non-allergic. In this sense, the present study aimed to report a clinical case where the framework of a removable partial denture was manufactured from a digital workflow, using polyether-ether-ketone as the material of choice, compared to a removable partial denture made with a cobalt-chromium framework. In this case, it was possible to perceive that the use of computer-aided design and computer-aided manufacturing technology for the construction of a removable partial denture framework of polyether-ether-ketone resulted in a denture with adequate adaptation and good aesthetics. Patient satisfaction, comfort, retention, number of follow-up sessions, masticatory performance and quality of life were evaluated. Compared with the conventional denture, the polyether-ether-ketone framework denture provided better satisfaction and comfort. Both prostheses showed similar results in terms of masticatory performance and in terms of quality of life, however the polyether-ether-ketone framework denture showed better results. In conclusion, polyether-ether-ketone proved to be a viable material for making removable partial denture framework. However, controlled and randomized clinical trials are needed to demonstrate the benefits of this treatment as an alternative in relation to the conventional denture

Longitudinal Clinical Evaluation of Undercut Areas and Rest Seats of Abutment Teeth in Removable Partial Denture Treatment

PURPOSE: Adequate preparation of abutment teeth for removable partial denture (RPD) rest seats allows appropriate masticatory force transmission, retention, and stability of supporting structures. It follows that careful preparation will be important for the longevity of the rehabilitation. The present study aimed to clinically evaluate rest seats and undercut areas of abutment teeth in RPD wearers after 2 years of use. MATERIALS AND METHODS: A total of 193 occlusal, incisal, and cingulum rest seats were evaluated in terms of shape, rest adaptation, wear, caries, fractures, and surface type (enamel, composite resin, or amalgam). Two hundred and fourteen undercut areas were evaluated in terms of surface type (enamel or restoration) and integrity. This study was approved by the Research Ethics Committee of the Federal University of Rio Grande do Norte, resolution 196/1996, protocol number 11/05. RESULTS: Intact preparations accounted for 92.2% of the total. Application of the Pearson test (p= 0.289) found no statistically significant differences among the materials on which the rest seats were prepared. For the undercut areas, 20.7% of those obtained on restorative material were nonintact. In addition, Fisher's exact test showed a statistically significant difference (p= 0.001) in surface type; enamel surfaces were shown to be 14 times more stable than restored surfaces. CONCLUSIONS: The results of this study suggest that rest seats are stable, regardless of the material on which they are prepared. Retentive areas were shown to be more stable when they were located in enamel

Conventional and digital impressions for complete-arch implant-supported fixed prostheses: time, implant quantity effect and patient satisfaction.

PURPOSE To evaluate and compare the effect of impression type (conventional vs digital) and the number of implants on the time from the impressions to the generation of working casts of mandibular implant-supported fixed complete-arch frameworks, as well as on patient satisfaction. MATERIALS AND METHODS 17 participants, 3 or 4 implants, received 2 types of digital impression methods (DI) and conventional (CI). In DI, two techniques were performed: scanning with the scan bodies (SC) and scanning with a device attached to the scan bodies (SD) (BR 10 2019 026265 6). In CI, the making of a solid index (SI) and open-tray impression (OT) were used. The outcomes were used to evaluate the time and the participant satisfaction with conventional and digital impressions. The time was evaluated through the timing of the time obtained in the workflow in the conventional and digital impression. The effect of the number of implants on time was also assessed. Satisfaction was assessed through a questionnaire based on seven. The Wilcoxon test used to identify the statistical difference between the groups in terms of time. The Mann-Whitney test was used to analyze the relationship between the time and the number of implants. Fisher's test was used to assess the patient satisfaction (P < .05). RESULTS The time with DI was shorter than with CI (DI, x̃=02:58; CI, x̃=31:48) (P < .0001). The arches rehabilitated with 3 implants required shorter digital impression time (3: x̃=05:36; 4: x̃=09:16) (P < .0001). Regarding satisfaction, the DI was more comfortable and pain-free than the CI (P < .005). CONCLUSION Digital impressions required shorter chair time and had higher patient acceptance than conventional impressions

Effect of acetyl resin retentive arms on the retentive force ofcircumferential clasps: an in vitro study.

PURPOSE: To compare and to evaluate the stability of the retentive force of cobalt-chromium (Co-Cr) circumferential clasps (control) to those with an acetyl resin retentive arm. METHODS: Sixteen specimens with a couple of circumferential clasps were made using Co-Cr over a metal model providing 0.25 mm undercuts. Eight specimens were fabricated without the anterior retentive arm, which was made later using acetyl resin (Dental D). Insertion and removal simulation test was performed through 7250 cycles. The retentive force was recorded in Newtons (N) for periods corresponding to 0, 1, 2, 3, 4, and 5 years. The data were subjected to ANOVA and Tukey test to compare periods and to Student's t test to compare groups (α=0.05). RESULTS: Mean (SD) is presented for Co-Cr and resin groups, respectively: 8.09(3.05) and 2.79(1.57) in period 0; 10.48(4.25) and 3.32(1.92) in 1 year; 10.09(4.15) and 3.47(1.81) in 2 years; 9.87(4.30) and 3.46(1.87) in 3 years; 9.46(3.93) and 3.27(1.59) in 4 years; 9.63(3.79) and 3.41(1.59) in 5 years. There were significant differences for Co-Cr between periods of 0 and 1 (p0.05). Comparisons between the groups showed statistical differences for all tested periods: 0 (p=0.0012), 1 (p=0.0013), 2 (p=0.0019), 3 (p=0.0031), 4 (p=0.0027) and 5 years (p=0.0014). CONCLUSIONS: Acetyl resin retentive arms, even if only in the anterior clasps, can significantly reduce the retentive force, but this force remained stable after 5 years of simulated use

Masticatory afficiency in denture wearers with bilateral balanced occlusion and canine guidance

The maintenance of masticatory function is especially important for patients wearing complete dentures due to their limitations. Thus, the bilateral balanced occlusal concept is used to achieve greater masticatory efficiency. However, a critical review of the literature reveals that there is not sufficient scientific evidence to support bilateral balanced occlusion as the most appropriate occlusal concept in complete dentures. Therefore, the aim of this study was to evaluate the masticatory efficiency in complete dentures wearers with bilateral balanced occlusion and canine guidance. A double-blinded controlled crossover clinical trial was conducted. The sample was composed by 24 edentulous patients who wore sets of complete dentures with both occlusal concepts during equal periods of 3 months. Objective data were collected through the masticatory efficiency test performed by the colorimetric method with the beads, in which capsules of a synthetic material enclosing fuchsine-containing granules were used. Subjective data were recorded by patient&apos;s ratings of their chewing function. No significant statistical difference was found for masticatory efficiency (p=0.095) between the two occlusal concepts studied. The results suggest that bilateral balanced occlusion does not improve the masticatory efficiency in complete denture wearers.A manutenção da função mastigatória tem importância especial em pacientes portadores de prótese total devido às limitações inerentes a esse tipo de prótese. Nesse contexto, a oclusão balanceada bilateral (OBB) é empregada com o intuito de obter-se uma maior eficiência mastigatória. Entretanto, analisando-se a literatura criticamente, observa-se que não existem evidências científicas suficientes que suportem a aplicação da OBB como conceito oclusal ideal em prótese total (PT). Assim, o presente trabalho teve o objetivo de verificar se pacientes portadores de PT dupla com OBB apresentam maior eficiência e capacidade mastigatória que aqueles com desoclusão com guia canino (DGC). Com esse intuito, realizou-se um ensaio clínico controlado duplo-cego do tipo crossover. A amostra foi composta de 24 pacientes portadores de prótese total dupla, onde todos fizeram uso de ambos os conceitos oclusais por períodos iguais de 3 meses. A avaliação da eficiência mastigatória foi realizada através do método colorimétrico com o uso de cápsulas mastigatórias. Não se encontrou diferença estatística significativa para a eficiência (p=0,0952) entre os dois conceitos oclusais estudados. Dessa forma, pode-se concluir que usuários de PT dupla com OBB não apresentam maior eficiência mastigatória que aqueles com DGC

Masticatory Efficiency In Denture Wearers With Bilateral Balanced Occlusion And Canine Guidance.

The maintenance of masticatory function is especially important for patients wearing complete dentures due to their limitations. Thus, the bilateral balanced occlusal concept is used to achieve greater masticatory efficiency. However, a critical review of the literature reveals that there is not sufficient scientific evidence to support bilateral balanced occlusion as the most appropriate occlusal concept in complete dentures. Therefore, the aim of this study was to evaluate the masticatory efficiency in complete dentures wearers with bilateral balanced occlusion and canine guidance. A double-blinded controlled crossover clinical trial was conducted. The sample was composed by 24 edentulous patients who wore sets of complete dentures with both occlusal concepts during equal periods of 3 months. Objective data were collected through the masticatory efficiency test performed by the colorimetric method with the beads, in which capsules of a synthetic material enclosing fuchsine-containing granules were used. Subjective data were recorded by patient's ratings of their chewing function. No significant statistical difference was found for masticatory efficiency (p=0.095) between the two occlusal concepts studied. The results suggest that bilateral balanced occlusion does not improve the masticatory efficiency in complete denture wearers.21165-