Description of a Rat Palatal Acrylic Plate That Can Be Relined.

PURPOSE: The objective of this article is to describe a method to construct an intraoral acrylic device that permits a reline material to be added to the inner surface of the palatal plate. MATERIALS AND METHODS: Fifteen 60-day-old adult female rats (Rattus Norvegicus Albinus Wistar), weighing 150 to 250 g were used for this study and allocated to three groups (n = 5): G1, animals wearing a heat-polymerized acrylic resin palatal plate (Lucitone 550) for 14 days; G2, animals wearing a heat-polymerized acrylic resin palatal plate (Lucitone 550) relined with Tokuyama Rebase II for 14 days; and G3, animals maintained under the same conditions as the experimental groups, without wearing palatal plates for 14 days. The manipulation of the animals followed the guidelines of the Brazilian College of Animal Experimentation, under the approval of the animal ethics committee of the State University of Ponta Grossa. The palatal plates covered the whole palate, were fixed in the molar region with light-cured resin, and were kept there for 14 days. The animals received a paste diet and water ad libitum. Before and after the trial period, the rats were weighed individually on a precision scale. Statistical analysis was performed using a two-way analysis of variance (α = 0.05) test for comparison of the animals' weight (g) at time 0 and after 14 days of using the palatal plate. RESULTS: No statistical differences were observed regarding the weight of the animals among the experimental groups in the study. CONCLUSIONS: The individual master impressions, the molar teeth coverage, and the method of cementation with nonadhesive composite resin provided good stability for the palatal plate showed in this study, not disturbing the eating habits and nutrition of the animals. This model seems reproducible, offering adequate histopathological evaluation. Differences in tissue morphology exist between the animals that used the palatal plate and the animals that did not use this device. Use of these palatal plates could clarify how prostheses bring changes in the palatal mucosa of users.

Histopathological changes by the use of soft reline materials: a rat model study.

AIM: To assess the histopathological changes of rat palatal mucosa exposed to soft reline materials. METHODS: Forty-five adult female Wistar rats with controlled living conditions and fed ad libitum were employed. Palatal appliances of heat-polymerized acrylic resin Lucitone 550 were manufactured and worn by forty animals during 14 days. Five animals did not use the appliances (G1) and were used to control the appliance influence. One experimental group (n = 10) used the appliances without any relining material (G2) to control the material effect. Three experimental groups (n = 10) received the following soft reline materials below appliances: Dentusoft (G3), Dentuflex (G4), and Trusoft (G5). Appliances from half of each experimental group(n = 5) was immersed in water bath at 55°C for 10 min before use. Animals were slaughtered and the palates were fixed in 10% buffered formalin. Hematoxylin and eosin stained sections of 5 µm were analyzed by computerized planimetry. Cellular compartment, keratin and total epithelial thickness, and basement membrane length were measured to histopathological description.Analysis of variance and Tukey post-hoc test were used to data examination(α = 0.05). RESULTS: For heat-treatment groups, G4 showed less elongated ridges at the basal layer interface (p = 0.037) than G2. When comparing the conditions with and without heat-treatment, only G2 showed a significant decrease in the cellular compartment, keratin layer and total epithelium thickness (p<0.05). CONCLUSION: The post-polymerization for Lucitone 550 was an effective method to reduce the changes in the rat palatal mucosa. The soft reline materials tested did not cause significant histopathological changes in the rat palatal mucosa.

Surface roughness of acrylic and silicone-based soft liners: in vivo study in a rat model.

PURPOSE: The aim of this in vivo animal study was to investigate changes in the surface roughness of soft liners over time. MATERIALS AND METHODS: Forty adult Wistar rats (Rattus norvergicus albinus) were fitted with acrylic custom-made palatal plates relined by dynamic impressions and tested with the following soft liners: Dentuflex (DF), Trusoft (TS), Dentusoft (DS), and Ufi Gel P (UG). Half of the animals for each tested material had the plates fitted during the material reline procedure. Their surface roughness was read immediately (IRa group, n = 5). The other half used the palatal plates for 14 days before roughness readings were performed (FRa group, n = 5). The surface roughness (Ra) of the inner surface from the relined dentures was recorded using a Surftest SJ-401 with eight readings per specimen, and mean values were obtained. Data (µm) were analyzed by two-way ANOVA and Tukey's test (α = 0.05). RESULTS: IRa means (2.92 ± 0.87 µm) and FRa means (3.35 ± 0.65 µm) were significantly different (p = 0.016). UG showed a lower (p = 0.01) Ra mean (2.1 ± 0.52 µm) than DF (3.94 ± 0.81 µm), TS (4.12 ± 0.64 µm), and DS (3.27 ± 0.64 µm). CONCLUSIONS: Ufi Gel P showed the smoothest surface among the materials evaluated. The period of use resulted in changes in the surface roughness of the materials tested.

Propiedades de materiales resilientes para rebase de prótesis: [revisión] / Properties of resilient materials used for relining dentures: [review]

La presente revisión de literatura tiene por objetivo mostrar las principales características, ventajas y limitaciones de los rebases blandos con el fin de acercar su utilización al clínico general. Los materiales resilientes para rebase de prótesis han sido desenvueltos para minimizar las posibles molestias causadas por las bases de las prótesis en la mucosa. Estos materiales forman un grupo de materiales elásticos que llenan total o parcialmente la base de las prótesis, con la finalidad de disminuir el impacto de la fuerza masticatoria sobre la mucosa de revestimiento, pudiendo ser utilizados como material temporal o de un carácter más permanente. Los rebases blandos además de clasificarse según el tiempo de uso como provisionales (corta duración) o permanentes (larga duración), estos pueden ser divididos según la base del material: acrílico o silicona. Dentro de las indicaciones se encuentran la estabilización de prótesis después de cirugías, el condicionamiento de tejidos fibromucosos, el rebase de prótesis provisionales durante el periodo de óseo integración de implantes o como medio retentivo para sobredentaduras implanto-soportadas, además pueden ser utilizados como material para impresiones funcionales. A pesar de que los materiales resilientes para rebase de prótesis poseen algunas desventajas, estos pueden ser usados para el rebase de prótesis removible parcial o total con un buen desempeño clínico, al indicarlas correctamente y por un tiempo determinado.

The objective of this literature review is to show the main features, advantages and limitations of soft liners to bring information for the general dentist use. Soft liners have been developed minimize any inconvenience caused by the hard bases of the prosthesis in the mucosa. These materials form a group of elastic materials that fill all or part of the prosthesis denture base, in order to reduce the impact force on masticatory mucosa, this soft liner can be used as temporary or more permanent material. Soft liners can be classified according to time of use as temporary (short term) or permanent (long term), and also these can be divided according to the material: acrylic based or silicone bases. The indications are stabilizing prosthesis after surgery fibromucosous tissue conditioning, the breaching of temporary restorations during the osseointegration of implants to over-retentive implant-supported dentures, it can also be used as material for functional impressions. Although soft liners have some disadvantages, they can be used for the relining of partial or complete removable prosthesis with a good clinical performance, with correct indications and for a given time.