Spontaneous early exposure of submerged endosseous implants resulting in crestal bone loss: A clinical evaluation between stage I and stage II surgery

Spontaneous early exposure of submerged implants during the osseointegratio n healing phase may be a harmful factor that results in early crestal bone loss around the implants. The objective of this study was to assess the eff ect of spontaneous early exposure on crestal bone loss around submerged imp lants, with special attention given to the relationship between the degree of exposure and the amount of peri-implant bone loss. Crestal bone level re lative to the shoulder of the implant was measured at the time of placement and at the time of exposure 4 to 5 months later During the period between stage I and stage II surgery, implant sites were observed, and each implant site in which spontaneous early exposure was detected was recorded. Perfor ations were classified according to the degree of implant exposure from Cla ss 0 (no perforation) to Class IV (complete exposure), Measurements from 20 6 implants in 64 patients produced 85 groups valid for statistical comparis on; each of these contained at least 2 lesions of different types. There wa s a statistically significant difference between bone loss associated with intact mucosa (Class 0) and Class I, Class II, and Class III lesions, and b etween Class I and II lesions. There were no significant differences betwee n Class I and III and between Class II and III. In Class II and III lesions , there was more bone loss associated with the buccal aspect of the implant s. Of the 115 perforated sites, 10 were associated with bone loss exceeding 2 mm, 2 presented 3 to 4 mm bone loss, 1 showed more than 4 mm, and 1 disp layed more than 5 mm. In view of the clinical implications that spontaneous early exposure may have on the success of osseointegration, prematurely pa rtially exposed implants should be exposed as soon as possible after the pe rforation is observed.