The effect of membranes on small, bone augmentations at dental implant placement

Several systematic reviews report on the success of implants placed in one-stage ridge augmentation procedures (bone augmentation simultaneous with implant placement) (Chiapasco & Zaniboni 2009, Kuchler & von Arx 2014). However, these systematic reviews can’t reach consensus about the beneficial use of a membrane in one-stage ridge augmentation procedures. Currently there are only two randomized controlled trials comparing one-stage ridge augmentations with and without membranes (Fu, et al. 2014, Park, et al. 2008). These two studies concluded that the addition of a barrier membrane prevented horizontal buccal bone resorption and enhanced bone thickness. No effect was seen on implant survival at one year. These studies describe large defects and fail to mention parameters of implant success and soft tissue aesthetics. In our clinical experience, there is no need for membranes in small buccal bony dehiscences, which can be managed by solely using locally harvested autogenous bone and bone substitutes. Therefore the aim of this of this randomized controlled trial is to determine the effect of membranes on small one-stage bone augmentations on implant survival, implant success, clinical and radiographic parameters, aesthetic results and patient satisfaction. The study is designed as a multicenter, prospective, randomized clinical trial (RCT). The study takes place at the University Medical Centre Erasmus MC, Rotterdam and the St. Anna Hospital, Geldrop.

The hypothesis is that small buccal dehiscences after implant placement can be reconstructed with a mixture of a bone substitute and autogenous bone with and without coverage of a membrane.

-Our second hypothesis is that implants with a small buccal bony dehiscence after implant placement reconstructed by one-stage bone augmentation perform equally well as implants completely covered in pristine bone

pre-operative, two weeks post operative, 6 weeks post operative and 1, 6 and > 12 months after placement of the crown.

Group A: the bony defect after implant placement is reconstructed with a mixture of autogenous bone and Straumann bone ceramic and covered with a membrane (Membragel)
Group B: the bony defect after implant placement is reconstructed with a mixture of autogenous bone and Straumann bone ceramic without use of a membrane

Group C: patients without bony dehiscence after implant placement are treated in a control group