Caroliene Meijndert

71 Bone level tapered implants in the maxillary aesthetic zone Comparison of our study’s outcomes with others that used the same bone level tapered implant in healed sites is, to the best of our knowledge, limited to two studies: Levine et al. (2019) and Pariente et al. (2020). They used the implant mainly in the posterior region and with other treatment protocols than the current study. Both studies also reported high survival rates (98%) and stable marginal bone levels (0.3±0.46 mm, Levine et al., 2019, and 0.35±0.23 mm, Pariente et al., 2020) after one and two years. In the absence of studies using the same implant brand, comparison can best be made with other implant systems with a tapered design applied to healed sites in the aesthetic region. De Bruyckere (2018) and Cosyn (2015) used the tapered NobelActive® implants (Nobel Biocare, Gothenburg, Sweden) and reported the same range of bone loss as Levine(2019) and Pariente(2020), one year after implant placement (-0.42±0.36 mm, Cosyn et al., 2015, and -0.48±0.4 mm, de Bruyckere et al., 2018). Zuiderveld (2018) used the NobelReplace CC implant (Nobel Biocare, Gothenburg, Sweden) and recorded bone level changes of +0.06±0.5 mm mesially and -0.01±0.4 mm distally in the time from definitive crown placement to 12 months thereafter. The present study’s results are in the same range as the mentioned studies and the bone level changes are comparable with the peri-implant bone level changes of the other tapered implants in the aesthetic region, including very little bone loss after the first year in function. An alleged benefit of a tapered implant design is a good primary stability due to the self-tapping property combined with underdrilling during osteotomy. Therefore, implant stability, was analysed by measuring the initial fixation (Implant Stability Quotient: ISQ). The implant stability quotient was not measured by Levine (2019) or Pariente (2020). Torroella-Saura et al. (2015) and Moroi et al. (2020) compared ISQ values of tapered implants with cylindrical implants. Although different implant brands were used, and mainly in the molar and mandibular region, they noted mean ISQ values at implant placement of 72.9±2.5 (Torroella-Saura et al., 2015) and 60.2±12.4 (Moroi et al., 2020) for the tapered implants, which were higher than for the cylindrical implants. Our study’s ISQ at implant placement was 73 [68;76], indicating high implant stability (The Ostell ISQ, 2020) and is comparable to the values measured with other implant brands and in the posterior mandibular region by Torroella-Saura (2015) and Moroi (2020). In addition to knowing this, Pariente (2020) did describe the mean insertion toque (IT) value. Being 34±5.3 Ncm. This can be classified as good primary stability (Kotsakis et al., 2014), even though the majority of the implants were placed in poor type III or IV bone (63.3%). At the time the study protocol was drafted, only little was known about the BLT implant, especially in the anterior zone, so it was decided to be careful when subjecting the study participants to immediate loading without knowing beforehand 4