Influence of immediate/delayed implant placement and implant platform on the peri-implant bone formation

To determinate the influence of the timing and position of the implant placement, as well as the presence and absence of a buccal gap, associated with different implant platforms on bone formation around implants.

In a first surgical stage, two premolars in one side of the mandibular arch of 07 mongrel dogs were extracted. After a 120-day healing period, a second-stage surgery was performed, in which a full flap was raised and two implants were installed. At this same stage, two contralateral premolars were extracted and two immediate implants were placed into the fresh sockets, through the "palatal approach technique" without flap elevation, totaling four implants per animal. The 28 installed implants constituted groups according to the timing (Immediate or delayed) of placement and the type of surface treatment. After 4 months, samples were collected and histomorphometric analysis was performed to determinate buccal surface BIC, lingual surface BIC, total BIC, buccal area, and lingual area of all implants. Kruskal-Wallis and pared Wilcoxon (P < 0.05) tests were performed for statistical analysis.

After 4-month healing period, the groups of immediate implants presented better BIC scores, mainly on the buccal surface. Data also suggest better bone area formation around the implants of these same groups. Concerning the type of implant platform, better results were found using Morse taper.

The flapless technique with "palatal approach," Morse taper implants, and immediate implant placement all have favorable influence on the bone formation around the implants.