This bachelor thesis has been carried out in collaboration with Maximatecc AB. In their office in Alfta they work with product development of both hardware andsoftware for various kinds of products including display computers and controllers for different kinds of equipment. In the product development process its common that several different kinds of additive manufactured (3D-printed) prototypes are ordered from an external company. The main objective with this thesis is to increase the knowledge about different kinds of additive manufacturing technologies that exists and are relevant for the company and how and why prototypes are important for the product development process. It will also with the help of interviews and observations at the company investigate how additive technologies are used today at Maximatecc and what other needs of the technology that exists. By doing so it will be determined if there is a need to buy an3D-printer or continue to order the service from an external company. A practical part of this thesis is to see if a component manufactured with different kinds of additive technologies is suitable to work as a substitute to an injection molded part in a product during the prototype phase. There could be a need for to buy a 3D-printer that uses FDM (fused depositionmodelling) -technology but it will not replace the need to buy in additive manufactured prototypes from an external company. This is because of the different kinds of desired attributes of the prototypes used during the product development process and the advantages and disadvantages of the different kinds of technologies. It was also concluded that components manufactured with additive technology could be used as a part in a functional product during the prototype phase. This could be used to send fully working prototypes to customers early in the product development process.

Sammanfattning Syfte Studiens syfte var att utvärdera bindningsstyrkan mellan protesbas och protestand beroende på framställningsteknik, med 3D-printning eller fräsning, och efter åldring.Material och metodTotalt framställdes 40 provkroppar varav 20 tillverkades genom 3D-printning (P) med SprintRay EU (SprintRay GmbH, Iserlohn, Tyskland) och 20 genom fräsning (F) med Ivotion (Ivoclar Vivadent AG, Schaan, Liechtenstein). Hälften av de frästa (TF) och 3D-printade provkropparna (TP), det vill säga 10 av varje, utsattes för 5 000 termocykler i temperaturerna 5 och 55 °C (T) och förvarades i destillerat vatten i 48 timmar vid en temperatur på 37° C. Bindningsstyrkan mättes genom ett skjuvkrafttest enligt standardiserade metoder.Envägs-ANOVA och Tukey’s test användes för statistisk utvärdering av resultaten där signifikansnivån sattes till α=0,05. En frakturanalys utfördes för att bedöma frakturtyper. Resultat Resultaten visade att P hade en signifikant högre bindningsstyrka än F (p<0,001). Skillnaden kvarstod även efter åldring. Det var ingen signifikant skillnad (p=0,626) i bindningsstyrkan mellan F och TF. TP uppvisade signifikant lägre bindningsstyrka jämfört med P (p=0,007).Alla F fick en adhesiv och kohesiv blandfraktur. P fick nio kohesiva och en adhesiv fraktur. TF fick sex adhesiva och fyra blandfrakturer. TP fick sju kohesiva och tre blandfrakturer. Slutsats 3D-printade material har en högre bindningsstyrka mellan protesbas och protestand jämfört med frästa. Åldring har en större negativ inverkan på bindningsstyrkan mellan protesbas och protestand om materialen är 3D-printade jämfört med om de är frästa. / Abstract Objective The aim of the study was to evaluate the bond strength between denture base and denture tooth depending on the manufacturing technique, fabricated through either 3D-printing or milling, and after ageing.Material and methods40 specimens were produced, 20 were produced through 3D-printing (P) using SprintRay EU (SprintRay GmbH, Iserlohn, Genmany) and 20 through milling (F) using Ivotion (Ivoclar Vivadent AG, Schaan, Liechtenstein). Half of the milled (TF) and printed specimens (TP), i.e., 10 of each group, underwent 5 000 cycles of thermocycling and were stored in distilled water for 48 hours at a controlled temperature of 37° C. Bond strength was evaluated using a shear bond strength test.One-way ANOVA and Tukey’s test were employed to assess the results with a significance level at α=0.05. Fracture analysis was conducted to evaluate the fracture type. Results The result showed that P had significantly higher bond strength compared to F (p <0.001). The difference remained after the ageing process. The comparison between F and TF yielded non-significant results (p=0.626). P had significantly higher bond strength than TP (p=0.007).All F had mixed fractures of adhesive and cohesive. P had nine cohesive and one adhesive fracture. TF had six adhesive fractures and the remaining were mixed fractures. TP had seven cohesive fractures and three mixed fractures. Conclusion 3D-printed materials have higher bond strength between the denture base and denture tooth compared to milled materials. Ageing has a greater negative impact on the bond strength between the denture base and denture tooth of printed materials compared to milled materials.