Background: The cementation of crowns to dental implant abutments is an accepted form of crown retention that requires consideration of the properties of available cements within the applied clinical context. Dental luting agents are exposed to a number of stressors that may reduce crown retention in vivo, not the least of which is occlusal loading. This study investigated the influence of compressive cyclic loading on the physical retention of cast crown copings cemented to implant abutments. Methods: Cast crown copings were cemented to Straumann synOcta titanium implant abutments with three different readily used and available cements. Specimens were placed in a humidifier, thermocycled and subjected to one of four quantities of compressive cyclic loading. The uniaxial tensile force required to remove the cast crown copings was then recorded. Results: The mean retention values for crown copings cemented with Panavia-F cement were statistically significantly greater than both KetacCem and TempBond non-eugenol cements at each compressive cyclic loading quantity. KetacCem and TempBond non-eugenol cements produced relatively low mean retention values that were not statistically significantly different at each quantity of compressive cyclic loading. Compressive cyclic loading had a statistically significant effect on Panavia-F specimens alone, but increased loading quantities produced no further statistically significant difference in mean retention. Conclusions: Within the limitations of the current in vitro conditions employed in this study, the retention of cast crown copings cemented to Straumann synOcta implant abutments with a resin, glass ionomer and temporary cement was significantly affected by cement type but not compressive cyclic loading. Resin cement is the cement of choice for the definitive non-retrievable cementation of cast crown copings to Straumann synOcta implant abutments out of the three cements tested.

Dental implant treatment has established benefits over traditional alternatives. Age-related changes in systemic and oral health in conjunction with social, economic and resource considerations often introduce complexities into dental implant treatment of ageing patients. When time, opportunity, discomfort and maintenance costs are coupled with cost-benefit and quality of life predictions, otherwise simple treatment decisions can become more difficult. Implants for different types of prostheses in both arches and the different types of prostheses themselves present a variety of treatment challenges, risks, benefits and maintenance requirements. This narrative review discusses selective literature pertinent to the provision of dental implant treatment in the ageing population.

Mandibular implant overdentures have established and predictable benefits over traditional mucosa-borne mandibular dentures and now form part of mainstream dentistry. Maxillary implant overdentures present a number of different challenges. This selective review highlights the paucity of evidence and inconsistent findings in the maxillary implant overdenture literature.

No abstract

BackgroundThe purpose of this study was to assess marginal gaps of CAD/CAM lithium disilicate crowns constructed using two different intraoral scanners of different generations.MethodsTwenty four Columbia model lower left molars were prepared for lithium disilicate crowns in a simulated environment by undergraduate students. The crown preparations were scanned by E4D and Trios 3 intraoral scanners and CAD/CAM lithium disilicate crowns designed and manufactured. The crowns were seated onto the original crown preparations and three vertical marginal gap measurements taken at four locations (mid‐buccal, mid‐lingual, mid‐mesial and mid‐distal) using a stereomicroscope. The mean marginal gap (MMG) was calculated for each crown and each individual tooth surface.ResultsThe MMG was not statistically significantly different for the Trios 3 and E4D scanners (P = 0.111). There was no statistically significant effect of measurement location on the tooth on the marginal gap (P = 0.1134).ConclusionsThere was no difference in the MMGs of CAD/CAM lithium disilicate crowns constructed using two different intraoral scanners of different generations. Within the limitations of this study, the advances in scanning technology have produced small and insignificant improvements in the accuracy of crown margins.