Peel bond strength between 3D printing tray materials and elastomeric impression/adhesive systems: A laboratory study.

OBJECTIVES: The present study aimed to evaluate the bonding between three 3D printed custom tray materials and three elastomeric impression/adhesive systems using the peel test. METHODS: Test blocks were 3D printed by three different technologies using Dental LT, FREEPRINT tray, and polylactide (PLA) tray materials. The reference test blocks were conventionally fabricated with Zeta Tray LC, a light-curing resin. The surface topographies of the four tray materials were investigated by scanning electron microscopy (SEM) analyses and roughness measurements. The peel bond strength between the four tray materials and three impression/adhesive systems, vinylsiloxanether (VSXE), vinyl polysiloxane (VPS), and polyether (PE), was measured (n=12 per group). The peeling failure modes and rupture sites were identified microscopically. RESULTS: The four tray materials featured different surface topographies. The peel bond strength was not significantly different with VSXE and PE, but PLA and the reference showed higher peel bond strength with VPS than the Dental LT and FREEPRINT tray (p<0.05). The rupture site of adhesive failure in all groups was partly at the adhesive-impression material interface and partly within the adhesive but never at the adhesive-tray material interface. SIGNIFICANCE: The 3D printed tray materials can achieve satisfactory chemical compatibility with the adhesives of VSXE, VPS, and PE. Surface topographies generated by the 3D printing technologies may affect bonding. Generally, 3D printed tray materials can provide clinically adequate bond strength with the elastomeric impression/adhesive systems. PLA is recommended for bonding with VPS when severe impression removal resistance is detected.

[What do General Practitioners and Dentists Report about their Cooperation? A Qualitative Exploration]. / Was berichten Hausärzte und Zahnärzte über ihre Zusammenarbeit? Ergebnisse aus einer qualitativen Exploration.

OBJECTIVE: Against the background of well-described associations between oral and general health, the cooperation between general practitioners (GPs) and dentists is crucial. Besides treatment, this includes prevention. Administrative referral between these two professions is not provided by statute. Thus, the study addresses the question: How do dentists and GPs integrate the associations between oral and systemic health in daily routine? METHODS: A total of 28 semi-structured interviews were conducted with GPs and dentists from 3 structurally different regions in the Federal State of Baden-Wurttemberg. Participants were visited in their office. The interviews were recorded, transcribed and analysed by 2 dentists and sociologists using Mayrings' qualitative content analysis. RESULTS: Associations between general and oral health are partially known to both practitioners. However, contact between them is limited. GPs send patients directly to dentists, without contacting them - mainly due to a desolate dental status, rarely due to therapy-resistant headache or facial pain. Dentists contact GPs to clarify mainly medication or anticoagulation medications taken by patients prior to invasive procedures. Preventive aspects play a minor part. Consultation essentially depends on acquaintanceship. CONCLUSION: Separation by statute determines the cooperation. Oral cavity in daily care is demarcated. Holistic patient care is hindered by a lack of knowledge and daily routines.