[Contribution and limitations of MIS(®) screwed expanders in the jaws: illustration from clinical cases and comparison of the osseous volume from three-dimensional radiographic pictures].

Screwed expanders are non-traumatic easy-to-use tools. They can be inserted like implants because they have a good self-tapping effect. Their use is more secure in narrow spaces; they are more comfortable for the patient than impacted expanders use. They allow increase of cancellous bone density, which improves primary stability in case of low density bone. Bone volume preservation and avoiding bone grafts can shorten the implant treatment procedure and decrease costs for the patient. Unfortunately, this technique does not allow alveolar ridge height increase. If this is required, onlay graft or guided tissue generation are the best alternatives.