implants - internationalmagazine of oral implantology

I clinical study _ flapless implant surgery 12 I implants4_2011 fection and reduced stability. The resulting overall survivalratewas99.7%.Ofthe236Straumannim- plants, 235 were clinically controlled with a mean follow-up period of 5.4 (0.75–8) years. The corre- spondingsurvivalrateforStraumannimplantswas therefore 99.6%. The mean follow-up period for the 102 Thommen implants was two (0.25–9.7) years. No Thommen implant had failed when this article was written. In this subgroup, one case of bisphosphonate-related osteonecrosis of the jaw (ONJ) was discovered, surprisingly, at the final fol- low-up. The two implants were retained following local and antibiotic treatment, i.e. were deemed survivors. None of the Z-Systems implants failed during the mean follow-up period of two (0.8–3.8) years. Sulcus bleeding on careful probing was ob- servedin19%oftheimplants(n=67).Withregard to the different manufacturers, BOP was observed in 14.9% of the Straumann implants (n = 35) and in 38.2% of the Thommen implants (n = 32). The differencewasstatisticallysignificant(Fisher’sex- act test, p<0.05). None of the nine Z-Systems im- plants showed BOP (Fig. 5). The evaluation re- vealed 89% of implants (n = 308) with a PD of be- tween 1 and 3 mm. A PD of 4 to 6 mm was found in 10% of implants (n=34). (The PD value distribu- tion for Straumann and Thommen implants is showninFig.6.)OnlyonefemalepatientwithaPD of 8 mm and 9 mm was documented (ONJ). No dif- ferences were found in PD between the three im- plant types. The mean PD of all 346 implants was 2.4 mm irrespective of the implant design. Ofallimplants,70%(n=244)weresurrounded by keratinised, attached gingiva (AG). This was the case for 68.5% of the Straumann implants (n=161),72.5%oftheThommenimplants(n=74) and 89% of the Z-Systems implants (n = 8; Fig. 7). Based on the results observed, an attempt was made to establish a correlation between: 1. AG and BOP; and 2. AG and PD. Attachedgingivaandbleedingonprobing The influence of soft tissue on peri-implant health is not conclusively elucidated. Of the 346 implants studied, 244 were surrounded by AG and only 27.9% (n = 68) of these exhibited BOP. Of the 236 Straumann implants, 161 were surrounded by AG and 26.4% (n = 38) of these were BOP positive. Of the 102 Thommen implants, 74 were sur- rounded by AG and 30.6% (n = 22) of these were deemed BOP positive. Of the nine Z-Systems im- plants, eight were surrounded by AG and all of them were BOP negative (Fig. 8). The difference in the number of patients with AG and positive BOP between Straumann and Thommen implants was statistically significant (p<0.05; 26.4 compared with 30.3%). Also the converse relationship, i.e. the correlation between the absence of AG and positiveBOP,wasalsoevaluated.Thiswasfoundin 67.9% of the Straumann implants (n = 38), com- pared with 64.7% of the Thommen implants (n = 22). The difference was statistically signifi- cant (p<0.05). Attachedgingivaandprobingdepth The mean PD for the 244 implants surrounded by AG was 2.4 (± 0.9) mm. The 102 implants with- outAGhadanidenticalPDof2.4(±0.7)mm.Asta- tistically non-significant trend was seen in the Thommen implants. The 74 Thommen implants surrounded by AG showed a PD of 2.2 (± 1.1) mm, whereas the 34 implants without AG showed a mean PD of 2.8 (± 1.4) mm. The eight Z-Systems implants surrounded by AG had a mean PD of 1.5mm.ThesingleimplantwithoutAGhadaPDof 2 mm (Fig. 9). Fig. 7_Attached gingiva. Fig. 8_Bleeding on probing for implants with AG. Fig. 7 Fig. 8