Influence of crown-to-implant ratio on periimplant marginal bone loss in the posterior region: a five-year retrospective study

Abstract

PurposeThe aim of this study was to evaluate the influence of the crown-to-implant (C/I) ratio on the change in marginal bone level around the implant and to determine the site-related factors influencing the relationship between the C/I ratio and periimplant marginal bone loss.MethodsA total of 259 implants from 175 patients were evaluated at a mean follow-up of five years. Implants were divided into two groups according to their C/I ratios: ≤1, and >1. Site-related factors having an influence on the relationship between C/I ratio and periimplant marginal bone loss were analyzed according to the implant location, implant diameter, implant manufacturer, prosthesis type, and guided bone regeneration (GBR) procedure.ResultsIt was found that 1) implants with a C/I ratio below 1 exhibited greater periimplant marginal bone loss than implants with a C/I ratio more than 1, 2) site-related factors had an effect on periimplant marginal bone loss, except for the implant system used, 3) the C/I ratio was the factor having more dominant influence on periimplant marginal bone loss, compared with implant diameter, prosthesis type, implant location, and GBR procedure, 4) implants with a C/I ratio below 1 showed greater periimplant marginal bone loss than implants with a C/I ratio greater than 1 in the maxilla, but not in the mandible, 5) and periimplant marginal bone loss was more affected by the implant system than the C/I ratio.ConclusionsWithin the limitations of this study, implants with a higher C/I ratio exhibited less marginal bone loss than implants with a lower C/I ratio in the posterior regions. The C/I ratio was a more dominant factor affecting periimplant marginal bone loss in the maxilla than the mandible. Meanwhile, the implant system was a more dominant factor influencing periimplant marginal bone loss than the C/I ratio.

Influence of Crown/Implant Ratio on Marginal Bone Loss: A Systematic Review

“…Forty‐four of the articles were excluded from the present study by not accomplishing the inclusion criteria as depicted in Figure 2. Only 13 articles were included in this systematic review 10‐13,15,16,27‐33 …”

“…Over the years, several publications reported the C/I ratios of their implant‐supported prosthesis 10‐12 . However, although some authors reported the anatomic C/I ratio, 13,14 others showed the clinical C/I ratio 15,16 . Although the clinical C/I ratio seems to describe a more realistic biomechanical scenario, 17 the anatomic C/I ratio is most commonly found in the literature.…”

“…Although some studies failed to show a correlation between the C/I ratio and MBL, 10,13,17 others reported higher amounts of MBL with increased C/I ratios 12 . Surprisingly, some studies even reported an inverse relationship between the C/I ratio and MBL, finding better results with higher ratios 15,16 . In addition, there is limited literature reporting the incidence of biologic and/or technical complications associated with this topic.…”

Risk Factors Associated With Implant Marginal Bone Loss

“…Misch 23 revealed that a C/I ratio of 0.5 to 1.0 reduces stress on the MBL, thereby preventing bone loss. Lee et al 19 revealed that implants with a C/I ratio below 1 exhibited greater peri-implant MBL than implants with a C/I ratio more than 1. Contrarily, Tawil et al 24 reported that C/I ratio did not prove to be a major biomechanical risk factor, as long as the occlusion is properly adjusted and occlusal contacts are placed as closely as possible to the emerging axis of the implant.…”

Análise da distribuição de tensões do conjunto implante/prótese de implantes de zircônia na região periimplantar

“…Da mesma forma que ocorre uma preocupação em relação à proporção desfavorável coroa-raiz em restaurações de coroa unitária, também existe um certo receio em relação à biomecânica das próteses implantossuportadas de peça única (VERRI et al, 2014). Uma proporção desfavorável coroa-implante (>1:1) poderia mostrar uma desvantagem biomecânica ao longo dos anos, uma vez que tais implantes podem ser menos resistentes a forças oclusais oblíquas, provocando aumento da tensão no tecido ósseo e componentes protéticos (NISSAN et al, 2011;LEE et al, 2012;VERRI et al, 2014;MORAES et al, 2015). O aumento da força oclusal pode causar perda óssea, fratura da porcelana, afrouxamento do parafuso dos pilares ou descimentação ou fratura dos componentes e até a perda da osseointegração (BLANES et al, 2007;BAYRAKTAR et al, 2013;VERRI et al, 2014).…”