In all edentulous cases, fig. 118, it must be determined if the mental bundle is on the crest or below it. In those situations where it is close, the incision must be made lingually so as not to cut off the bundle, fig. 119. Careful reflection of the tissues and exposure of the bone reveals both bundles to be right near the top of the resorbed ridge, fig. 120. Care must be taken not to sever any portion of the bundles going to the cheeks, figs. 121, 122. For extreme accuracy an acrylic tray was moulded directly over the exposed bone and then notched for retention, fig. 123, for the rubber base impression material, fig. 124. The tissues were closed, fig. 125.

Three weeks later the implant was placed over the bone, figs. 126, 127, 128, 129, 130, and the tissues were sutured, fig. 131. Figs. 132, 133 show the acrylic stent. The superstructure

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