Esthetic options for the fabrication of removable partial dentures: a clinical report

Esthetic Clasp Cast Partial Denture

Denture esthetics as defined by Glossary of prosthodontics terms the effect produced by a dental prosthesis that affects the beauty and attractiveness of the person. [1] Removable partial dentures (RPDs) are the widely accepted and treatment of choice for most cases as it is both effective and affordable. Partially edentulous treatment planning includes both esthetics and masticatory function. A prosthesis that is highly esthetic will improve patient's motivation and acceptance. It is a very wrong notion to expect that patients will tolerate unesthetic partial dentures because good masticatory capability has been achieved. Esthetics plays a vital role in the success of partial dentures, and the length and mobility of the patient's lips play a significant role in achieving it. [2] Patients with short lips or highly mobile lips pose problems as esthetics are compromised because most clasp arms, denture borders, and other components will show when the patient smiles or speaks. [3] RPDs can easily look artificial; hence, special emphasis should aim toward restoring function, phonetics, esthetics with a long-term benefits which requires meticulous attention during fabrication. This case reports is an esthetic clasp designed for a cast partial denture for a young girl for esthetic and function.

Volumetric Change as a Parameter for the Accuracy of Impression Materials

In this paper we studied the behavior of some impression materials such as alginate, condensation and addition silicones, considering the following parameters: the reproductive capacity of morphological details - dimensional stability - the ability to reproduce with accuracy the ratio between morphological elements. The essential conditions that an impression material should fulfill are plasticity, fidelity, flexibility, good mechanical strength, dimensional stability, suitable setting time and compatibility with materials from which the models are manufactured.The study results indicated that condensation silicones present the highest volumetric changes, their contraction being the result of the evaporation of volatile byproducts.The dimensional stability of fingerprint materials is one of the variables that contribute to the accuracy or inaccuracy of dental prostheses, other factors being represented by the changes occurring during the preparation of the fingerprint material as well as the fingerprinting techniques.

Oral health-related quality of life in patients with non-metal clasp dentures: a randomised cross-over trial

We investigated the efficacy of non-metal clasp dentures (NMCDs) with regard to the oral health-related quality of life (OHRQoL) and compare the findings with those for conventional metal clasp-retained dentures (MCDs). This single-centre, randomised controlled, two-phase, open label, cross-over trial included 28 partially dentate individuals. The patients were randomised to receive MCDs followed by NMCDs, or the opposite sequence (n = 14 in each group); each denture was worn for 3 months. OHRQoL was evaluated using the Oral Health Impact Profile-Japanese version (OHIP-J) at entry (T-entry; before treatment with the first denture) and at 3 months after treatment with each denture (T3). An examiner evaluated denture stability, oral appearance and surface roughness before denture delivery (T0) and at T3 and denture hygiene at T3. A total of 24 patients completed the trial. There were no complications related to the dentures, abutment teeth or denture-bearing mucosa during the follow-up periods for both dentures. The mean OHIP summary score was lower for NMCDs than for MCDs, and the difference (9 points) was greater than the minimal important difference (6 points), indicating the difference was clinically relevant. The effect size was medium (0·70). Statistical analyses with linear mixed models found a significant effect of the denture type on the OHIP summary score and scores for the Oro-facial appearance, Oro-facial pain and Psychological impact domains (NMCD < MCD; P < 0·05). The results of our study suggest that NMCDs allow for better OHRQoL compared with MCDs.

Scratch test of thermoplastic denture base resins for non-metal clasp dentures

PURPOSE

Several thermoplastic denture base resins have been introduced for the fabrication of non-metal clasp dentures. Although the surface of these materials is easily damaged, the surface roughness and characteristics of scratches created have not been evaluated. The purpose of this study was to evaluate the surface roughness of thermoplastic resins using a scratch test for the development of future materials.

METHODS

Four thermoplastic (polyamide: Valplast(®); VLP and Lucitone FRS(®); FRS, polyethylene terephthalate: EstheShot(®); ES, and polyester: EstheShot Bright(®); ESB) and two conventional acrylic (Heat-polymerizing: Urban(®); HC, and Pour type auto-polymerizing: Pro-Cast DSP(®); PR) denture base resins were examined. Eight specimens, approximately 10mm×10mm×30mm in size, of each material were fabricated. Scratch test was performed by a scratch tester with a diamond indenter of 10-μm radius and cone angle 90°, applying a constant load of 500mN, and 2-mm-long scratches were made. The scratch marks were studied under 3D laser measuring microscope and cross-section profiles at approximately 0.5mm, 1.0mm, and 1.5mm from the starting point were extracted and measured with analysis software. Data from 24 cross-section profiles in each denture base material were analyzed.

RESULTS

The maximum depths of ES, ESB and FRS were greater than VLP, PR and HC, and the scratch widths of ES, ESB, FRS and VPL were greater than PR and HC.

CONCLUSIONS

The results showed that the surface of thermoplastic denture base resins was easily damaged compared to polymethyl methacrylate.

Effect of acetyl resin retentive arms on the retentive force of circumferential 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 (p<0.001), 0 and 2 (p<0.01) and 0 and 3 (p<0.05). In the resin group, no significant differences were found between periods (p>0.05). 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.

A removable partial denture using an esthetically designed round-rest distal clasp on maxillary anterior abutment teeth: a clinical report

A round-rest, distal depression clasp is suggested as an esthetic alternative to a conventional clasp for maxillary anterior teeth serving as abutments for a removable partial denture. A lingual round rest provides support for the prosthesis, and a mesiolingual reciprocating plate is present. A split minor connector engages a distal depression for retention. The facial surface of the abutment displays no metal and provides an esthetic result.

T-bar clasp-retained removable partial denture as an alternative to implant-based prosthetic treatment

This article reports the case of a 55-year-old female patient who presented with unsatisfactory temporary crowns in the right mandibular premolars and molars, and a premolar-to-molar fixed partial denture in the left side. The clinical and radiographic examinations revealed a fracture of the left first premolar that was a retainer of the fixed partial denture and required extraction. Initially, the acrylic resin crowns were replaced by new ones, and a provisional RPD was made using acrylic resin and orthodontic wire clasps to resolve the problem arising from the loss of the fixed partial denture. Considering the patient's high esthetic demands, the treatment options for the definitive prosthetic treatment were discussed with her and rehabilitation with implant-supported dentures was proposed because the clinical conditions of the residual alveolar ridge were suitable for implant installation, and the patient's general health was excellent. However, the patient did not agree because she knew of a failed case of implant-retained denture in a diabetic individual and was concerned. The patient was fully informed that implant installation was the best indication for her case, but the arguments were not sufficient to change her decision. The treatment possibilities were presented and the patient opted for a clasp-retained removable partial denture (RPD) associated with the placement of crowns in the pillar teeth. The temporary RPD was replaced by the definitive RPD constructed subsequently. Although RPD was not the first choice, satisfactory esthetic and functional outcomes were achieved, overcoming the patient's expectations. This case report illustrates that the dentist must be prepared to deal with situations where, for reasons that cannot be managed, the patient does not accept the treatment considered as the most indicated for his/her case. Alternatives must be proposed and the functional and esthetic requirements must be fulfilled in the best possible manner.