The Influence of Vertical Implant Position on the Marginal Bone Loss in Thick Versus Thin Phenotype.

Multiple clinical studies have established high survival rates and tremendous predictability of dental implant treatment (Schiegnitz and Al-Nawas 2018). However, a pleasant esthetic outcome is the patient's primary expectation regarding implants in the esthetic zone (Vermylen et al. 2003)and several esthetic factors have been evaluated to contribute to an esthetic appearance. Among these, the midfacial soft tissue level is considered to be one of the most important factors; Cosyn and co-workers reported that among factors including soft tissue phenotype, the midfacial recession was associated with the position of the implant (Cosyn et al. 2012).

Therefore, subcrestal implant placement has been advocated as it has been associated with the reduction of crestal bone loss in cases with decreased soft tissue thickness. If the vertical soft tissues on the crest of the alveolar ridge are 2 mm or less at the time of implant placement, implants will undergo unavoidable bone resorption by establishing sufficient biologic protection. Another option was proposed by Linkevicius et al, who introduced the subcrestal implant placement as a method to accommodate the problem of thin soft tissues.(Linkevicius et al. 2020).

Limiting the extent of peri-implant bone loss has been recognized for decades to be an important aspect of long-term implant success, and stable peri-implant bone conditions play an important role in maintaining esthetics (Laurell and Lundgren, 2011).

The opinion expressed widely in the scientific literature has been that subcrestal implant placement leads to increased crestal bone resorption. However, clinical studies addressing the implant placement depth in relation to crestal bone have been rare. Data on subcrestal versus crestal placement have mostly come from animal studies. Even fewer data are available regarding the effects of crestal versus subcrestal positioning of platform-switched implants (Cochran et al., 2009).

This study aims to compare the effect of different vertical implant position with immediate provisionalization on marginal bone loss thin and thick vertical tissue biotype.