Displacement of Simulated Flabby Tissue by Different Tray Designs and Impression Materials

Integration of an intraoral scan and a conventional impression for fabricating complete dentures for a patient with flabby tissues

Inflammatory movable tissues in the maxillary anterior region are the result of excessive stimulation of the anterior alveolar ridge, as the maxillary denture habitually rotates anteriorly and upward during mastication. The pressure required for a functional impression makes it difficult to obtain the accurate anatomy of the inflamed mucosal tissues. An intraoral scanner can be used to record the movable tissues in an immobile state. However, for removable dentures, the oral scanner is limited by the difficulty in evaluating the denture borders or the posterior palatal seal area accurately. The fabrication of a complete denture by combining the use of an oral scanner to capture an anatomic impression without exerting pressure on the maxilla, including the movable tissues, and a traditional functional impression using the closed-mouth technique is described.

Management of Flabby Edentulous Ridge Using the Window Impression Technique

Flabby ridge, also known as a mobile or displaceable ridge, is a common clinical challenge encountered in dental practice. The flabby ridge lacks firmness and stability, causing dentures to become loose and unstable. This can lead to discomfort, difficulty in speaking and eating, and a decreased quality of life for denture wearers. The flabby ridge often lacks the necessary contour and resilience to create an effective seal and maintain suction between the denture base and the underlying tissues. This compromises the retention of dentures, making them prone to dislodgement during normal oral functions. In this report, a modified window technique is presented for the impression of the anterior maxillary flabby ridge. The window ensures that no or little pressure is exerted on the flabby tissue. Therefore, this technique can be easily carried out by general dental practitioners, enabling them to manage flabby ridge complete denture cases within a primary dental care setting.

Managing Fibrous Maxillary Ridge: A Case Series of Impression Techniques

Fibrous ridges on the edentulous maxillary arch are commonly found in combination syndrome or due to ill-fitting dentures. Often, these cases are managed conservatively using modified impression techniques to achieve better support and peripheral seal without displacing the movable tissue. Many impression techniques were proposed and justified with their respective ideologies, but some may complicate both the clinical and laboratory procedures. In this report, two simplified techniques are demonstrated to make an impression of the maxillary arch with fibrous ridges. Laboratory steps in custom tray fabrication are also emphasised for a successful and predictable impression.

Custom double tray for a special impression technique for flabby maxillary residual ridge: Case report

The construction of a removable dental prosthesis for patients with compromised residual alveolar ridges is a challenge for prosthodontists. Flabby anterior ridges and hypermobile tissues in completely edentulous arches require special considerations during prosthetic management, especially when natural dentations remain on the opposite side. Previous studies have revealed that the displacement of flabby tissue can be reduced during impressions by controlling the applied forces via changes in factors such as the tray design, scraping of impression trays, impression material, window technique, and seating velocity of the impressions. However, there may still be some forces applied during impression or there is no even space because there are no trays supporting the vinyl polysiloxane (VPS) impression material in the open window area. Using a custom double tray with even gap between these trays and injecting light body impression material may eliminate these forces and provide accuracy due to even space for the impression material. This article is a clinical report of a patient who presented with an anterior flabby maxillary edentulous ridge opposing the remaining anterior natural teeth. A custom double tray was fabricated using the principle of the window technique. The gap between the double trays allows mucostatic impressions of flabby ridge tissue to be made with accuracy. The maxillary single denture, which was made with a custom double tray, satisfied the patient.

Quantitative analysis of the selective pressure impression technique using CAD-CAM technology: A pilot clinical study

STATEMENT OF PROBLEM

Quantitative 3D clinical analysis of the selective pressure impression technique directly measuring tissue displacement during impression making for complete maxillary dentures is lacking.

PURPOSE

The purpose of this clinical study was to digitally compare impressions made of the edentulous maxillary ridge by using the selective pressure impression technique with different amounts of relief incorporated into custom tray designs.

MATERIAL AND METHODS

Nine participants receiving maxillary complete dentures were enrolled in the study. An initial custom tray was fabricated in urethane dimethacrylate by using the alternative border molding technique without relief and scanned to create a standard tessellation language (STL) file from which 3 groups of custom trays were designed and 3D printed with 0.0-mm (no relief), 1.0-mm, and 3.0-mm relief over the anterior ridge and median palatal suture. Definitive impressions using each of the 4 custom trays were made with a consistent volume of light-body polyvinyl siloxane impression material. The definitive impressions were scanned, and the STL files were superimposed to investigate the topographical differences among the groups, each with respect to the no relief, 3D-printed custom tray definitive impression. Mean volumetric differences for all 3 groups were measured in areas where relief was used and statistically analyzed with the Friedman test (α=.05).

RESULTS

No significant difference was found among any of the 3 groups of superimposed impressions in areas of no relief, 1.0-mm, and 3.0-mm relief (P=.558). The mean difference ±standard deviation for each comparison in regions of the anterior ridge and median palatal suture were 0.07 ±0.06 mm for no relief, -0.03 ±0.07 mm for the 1.0-mm tray relief, and -0.04 ±0.09 mm for the 3.0-mm tray relief. The negative values in mean difference indicated less compression of underlying tissues compared with the reference border molded urethane dimethacrylate custom tray impression.

CONCLUSIONS

Although results showed less compression when compared with that of the control group, custom tray relief of 1.0 mm and 3.0 mm over the anterior residual alveolar ridge and median palatal suture did not significantly impact the resulting impression topography when compared with no relief custom trays.

Determining the Effects of Eugenol on the Bond Strength of Resin-Based Restorative Materials to Dentin: A Meta-Analysis of the Literature

The aim of this study was to determine whether the residual presence of eugenol in coronal dentin may compromise the bond strength of resin-based restorative materials. A search was performed on MEDLINE/Pubmed, Scopus, and by hand search for relevant papers. No restriction was applied for language and publication date. The studies selected for analysis tested specimens with reduced size (micro-shear bond strength (µSBS) and micro-tensile bond strength (µTBS)) of adhesive systems and resin-based restorative materials applied to coronary dentin “contaminated” with eugenol-based materials. The search provided 335 articles, but only 10 studies met the inclusion criteria. The pooled global analysis showed a significant influence of eugenol, as it negatively influenced the bond strength of resin-based restorations (5.79 (3.31–8.28) MPa, p < 0.00001). The subgroup analyses for conventional etch-and-rinse (p = 0.003) and self-etch (p < 0.0004) adhesive systems, as well as for µSBS (p = 0.01) and µTBS (p < 0.0001), showed a negative influence of eugenol on the bond strength. Data were statistically heterogeneous. However, it was possible to observe that eugenol could negatively affect the bonding of resin-based restorative materials to dentin. Further evidence is necessary in order to acquire more accurate information about this issue and confirm that the residual presence of eugenol in dentin compromises the bond strength of resin-based materials.