The effect of new acrylic full removable dentures on food taste.

OBJECTIVE: To find out how the use of new acrylic full upper removable dentures changes the perception of four basic tastes: sweetness, sourness, saltiness and bitterness, and to evaluate the influence of age and gender. MATERIAL AND METHODS: This study was performed in LSMU MA Faculty of Odontology Department of Prosthodontics during 2017-09-01 - 2018-02-01. All the patients for whom new acrylic upper removable dentures were made were invited to take part. 30 patients have taken part. Sixteen solutions for basic tastes: sweetness, sourness, saltiness and bitterness; were made. The patients were examined without and with their new dentures. The patients were told to rinse an unknown solution starting from the lowest concentration and to identify the taste. Data analysis was performed using SPSS® (IBM®, Armonk, USA) version 23. RESULTS: Patients with full upper removable dentures felt sweet (p=0.002) and sour (p=0.000) taste weaker than without them, the same tendency was observed with bitter (p=0.063) and salty (p=0.059) taste. The time required to identify the taste was longer with removable dentures than without them (p<0.05). Identification of saltiness became weaker both with and without removable dentures as the age of the patients increased (p<0.05). Bitterness was identified better by women than men both with and without removable dentures (p<0.05). Age and gender had no influence on other basic tastes (p>0.05). CONCLUSION: The results of this study confirm the presumption that acrylic full upper removable dentures weaken the taste perception of the patients.

Stress in the bone and prosthetic components due to "all-on-4" system with polyether-ether-ketone screwing prosthesis. Analysis using 3D finite element method.

OBJECTIVE: To identify and analyze distribution of bone stress in the implant area using a PEEK prosthesis fixed on four dental implants depending on different positions of the functional loading point on a cantilever in a 3D modeled system. MATERIAL AND METHODS: The fragment of the lower jaw with dental implants and over-the-implant prosthetic part was represented by geometrical 3D models and diagonal loads were placed on the distal cantilever of the prosthesis. 3D models were exported to SolidWorks® Student Edition 2018 (Dassault Systemes SE, France) software. Average von Mises stress around the outer perimeter of the implant was measured in MPa. Relative stress was identified using a graded color scale in relative units. A 0.95 confidence level (P), 0.05 significance level (p), maximum error of 10% (Δ) were set. The data was analyzed using Statistical Package for Social Sciences® (IBM, Armonk, USA) version 137. RESULTS: The distal implant on the same side as the point of loading receives 45.01-53.88% of all forces created. Stress at the frontal implants is distributed almost evenly. The pair of implants on the same side of the loading force suffers 66.38-74.68% of all forces. The implant on the opposite side of the loading force receives the smallest stress which is hardly influenced by the length of the console. CONCLUSION: A full arch restoration in an edentulous lower jaw using a four-implant fixed PEEK prosthesis system generates unevenly distributed internal stress in the bone next to the implants but does not go over the critical resistance of the bone.