COMPARISON OF HEALED TISSUES ADJACENT TO SUBMERGED AND NON-SUBMERGED UNLOADED TITANIUM DENTAL IMPLANTS - A HISTOMETRIC STUDY IN BEAGLE DOGS

This study involved histometry of the healed tissues around submerged and nonsubmerged dental implants in beagle dogs. In a split-mouth desi gn, 19 submerged and 19 nonsubmerged commercially pure titanium implan ts, titanium plasma-sprayed in the bone anchoring part and smooth in t he transmucosal portion, were placed in the mandibles of 6 dogs. Oral hygiene was performed 3 times weekly. After 3 months of healing, trans mucosal abutments were inserted in the submerged implants. Six weeks a fter second stage surgery, the dogs were sacrificed and specimens obta ined and processed for histology and histometry. Using a light microsc ope and a digitizing pad, the distance from implant top to mucosa bord er (DIM), the extent of epithelial downgrowth (ED), the attachment lev el (AL), the length of connective tissue contact (CTC) and the distanc e of the first coronal alveolar bone contact from the implant top (DIB ) were measured at the mesial and distal aspects. Means+/-standard dev iations for submerged and nonsubmerged implants were calculated, with the dog being the unit of measure. No statistically significant differ ences between submerged and nonsubmerged implants were found for DIM, CTC and DIB. However, significant differences were observed for ED and AL. This study in beagle dogs indicates that the apical extension of the peri-implant epithelium is significantly greater and the attachmen t level significantly lower adjacent to submerged implants with second -stage transmucosal abutments than in nonsubmerged, one-stage implants .