Placement of two-part implants in sites with different buccal and lingual bone heights

Recipient sites for implants often exhibit a vertical discrepancy between the buccal and lingual bone crest. The potential to preserve the lingual bone when placing the implant within the dimension determined by the buccal bone in such sites remains to be evaluated.

Five dogs were included in this study. The premolars were extracted on one side of the mandible, and a buccal defect was prepared by the resection of a 2-mm-high portion of the buccal bone wall. Three months later, two test (surface modification on the shoulder part of the implant) and two control implants were placed within the area of the buccal bone defect. Following placement, the implant margin at the buccal side coincided with the buccal bone crest, whereas the implant margin at the lingual side was in a subcrestal position. Regular abutments with a turned surface were connected to the control implants, whereas experimental abutments with a modified surface were connected to the test implants. A plaque-control program was initiated. Four months later, biopsies were obtained and prepared for histologic analysis.

The marginal bone level was located at a more coronal position at the lingual aspect than at the buccal aspect of the test implants, whereas the buccal and lingual bone levels were similar at control implants.

It is suggested that different marginal bone levels are obtainable at the lingual and buccal aspects when two-part implants with suitable surface characteristics are placed in sites with different buccal and lingual bone heights.