In his article, “Assessing the space limitation inside a complete denture for implant attachments” J Prosthet Dent 2003;89:82-5, Dr. Nopsaran Chaimattayompol, describes the following technique for visualizing the actual space available for attachments.

Either create a new wax up, or use the existing prosthesis, which satisfies all the criteria of the final prosthesis in terms of cosmetics and function. Using a silicone putty, create a cast of the arch by placing the material in the denture or wax up. In this way, the denture will seat well on the model, and there is only a short wait for material set. After confirming that the denture fits on the model, notches are cut in the base of the silicone model. The denture and base are lightly vaselined and a second mix of silicone putty is placed over the denture and model, engaging the notches thus becoming a mild of the denture in relation to the ridge.

By sectioning the mold of the denture at critical spots and repositioning it on the model via the notches, an accurate representation of the space available for restorative parts can be obtained. Preoperative utilization of this technique will allow for alterations in either the surgical or prosthodontic treatment plans when the available space is too close. This type of technique is also valid for fixed prosthetics.

Prosthetic fractures and metal show through can hopefully be avoided by confirming the actual space there is to work with. There is nothing worse than continuous breakage on a recently completed case with no way to correct it.

Trimmed silicone putty cast	A, Silicone putty adapted over acceptable existing mandibular complete denture. B, Negative impression of existing complete denture made from silicone mold.
Existing complete denture on trimmed silicone putty cast. Note multiple notches scored on borders of putty cast (arrows)	A, Sectioned silicone mold over area of anticipated implant positions engaging multiple notches. Space limitation can be measured before implant surgury. B, Anticipated independant implant over denture attachment can be "tried in" by turning upside down to fit within space.

A, Mandibular silicone putty cast with sectioned silicone mold over healing abutment (arrow) after implant surgury. B, Example of selected independant implant over denture attachment with metal housing placed upside down to fit into space.