Biomedical subjects

Marco Antonio Compagnoni

Publications and source records attributed to Marco Antonio Compagnoni.

5 recordsLinked to original sources

PubMed2004

Kinesiographic study of complete denture movement related to mucosa displacement in edentulous patients.

The mucosa that covers the residual ridges of edentulous patients may present some distortion or displacement when occlusal loading is applied in complete dentures. This distortion and movement of the denture can result in acceleration of residual ridge resorption and loss of retention and stability. The aim of this study was to analyze the pattern of upper complete denture movement related to underlying mucosa displacement. A sample of 10 complete denture wearers was randomly selected, which had acceptable upper and lower dentures and normal volume and resilience of residual ridges. The kinesiographic instrument K6-I Diagnostic System was used to measure denture movements, according to the method proposed by Maeda et al.7, 1984. Denture movements were measured under the following experimental conditions: (A) 3 maximum voluntary clenching cycles and (B) unilateral chewing for 20 seconds. The results showed that under physiological load, oral mucosa distortion has two distinct phases: a fast initial displacement as load is applied and a slower and incomplete recovery when load is removed. Intermittent loading such as chewing progressively reduces the magnitude of the denture displacement and the recovery of the mucosa is gradually more incomplete.

Aged↗

PubMed2004

The effect of polymerization cycles on porosity of microwave-processed denture base resin.

STATEMENT OF PROBLEM: Although most of the physical properties of denture base resin polymerized by microwave energy have been shown to be similar to resins polymerized by the conventional heat polymerization method, the presence of porosity is a problem. PURPOSE: This study evaluated the effect of different microwave polymerization cycles on the porosity of a denture base resin designed for microwave polymerization. MATERIAL AND METHODS: Thirty-two rectangular resin specimens (65 x 40 x 5 mm) were divided into 3 experimental groups (A, B, and C; Onda-Cryl, microwave-polymerized resin) and 1 control group (T; Clássico, heat-polymerized resin), according to the following polymerization cycles: (A) 500 W for 3 minutes, (B) 90 W for 13 minutes+500 W for 90 seconds, (C) 320 W for 3 minutes+0 W for 4 minutes+720 W for 3 minutes, and (T) 74 degrees C for 9 hours. Porosity was calculated by measurement of the specimen volume before and after its immersion in water. Data were analyzed using 1-way analysis of variance (alpha=.05). RESULTS: The mean values and SDs of the percent mean porosity were: A=1.05%+/-0.28%, B=0.91%+/-0.15%, C=0.88%+/-0.23%, T=0.93%+/-0.23%. No significant differences were found in mean porosity among the groups evaluated. CONCLUSION: Within the limitations of this study, a denture base resin specifically designed for microwave polymerization tested was not affected by different polymerization cycles. Porosity was similar to the conventional heat-polymerized denture base resin tested.

Acrylic Resins↗

PubMed2004

A variation on split-cast mounting for complete denture construction.

This article describes a variation of the split-cast mounting technique wherein the border of the definitive cast is wrapped with masking tape to form a container for the dental plaster normally used to affix the cast to the articulator. The entire inferior surface of the cast is coated with a thin film of petroleum jelly, and the cast is mounted in the articulator. After the dental plaster has set, the cast is retained by means of the masking tape. The cast is separated from the dental plaster simply by removing the masking tape.

Adhesives↗

PubMed2002

Changes in occlusal vertical dimension in microwave processing of complete dentures.

This study investigated the effect of different microwave curing cycles on the changes in occlusal vertical dimension of complete dentures. Four test groups with 12 maxillary dentures each were evaluated. Groups 1, 2 and 3 were polymerized with different cycles by microwave radiation and Group 4 was the control and cured by water bath. The average pin opening for all groups was less than 0.5 mm. There was no significant difference between the groups polymerized by the microwave method and the control group. However, analyses of the vertical dimension changes showed statistically significant differences between groups 2 (0.276 +/- 0.141 mm) and 3 (0.496 +/- 0.220 mm).

Acrylic Resins↗

PubMedDate not supplied

Relation between speaking space of the /s/ sound and freeway space in dentate and edentate subjects.

The purpose of this study is to assess the relation between the speaking space of the /s/ sound and the freeway space in two subject groups. One group had natural dentition (Group I, n = 61) and the other comprised complete denture wearers (Group II, n = 33). The analysis was done by means of a jaw-tracking device (K6-I Diagnostic System, Myotronics Research Inc., Seattle, WA, USA). Freeway space was determined by asking the subjects to occlude from the postural rest position. Speaking space of /s/ was measured during the pronunciation of the word "seis" and comprised the mean distance from the /s/ speaking position to maximal intercuspation. A weak correlation was found between the speaking space of /s/ and the freeway space in Group I (r = 0.41, p < 0.01), but in Group II, the correlation was stronger (r = 0.75, p < 0.01). The speaking space of /s/ and freeway space were different in Group I, but statistically similar in Group II (paired t-test, alpha = 0.05). It can be suggested that anatomic changes following prosthetic procedures caused a functional adaptation which resulted in more similar values for the speaking space of /s/ and the freeway space.

Adult↗