Peri-implant conditions and marginal bone loss around cemented and screw-retained single implant crowns in posterior regions: A retrospective cohort study with up to 4 years follow-up.

Hong-Chang Lai,Lin-Feng Fan,Daniele Botticelli,Long-fei Zhuang,Jie-Ni Jie-Ni,Jun-Yu Shi,Xiao-Meng Zhang

doi:10.1371/journal.pone.0191717

Hong-Chang Lai, Lin-Feng Fan + Show 5 more

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https://doi.org/10.1371/journal.pone.0191717

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Journal: PloS one	Publication Date: Feb 5, 2018
Citations: 13	License type: CC BY 4.0

Affiliation: Shanghai Ninth People's Hospital

Abstract

The aim of the present study was to identify the peri-implant conditions (bleeding on probing (BOP), pocket probing depth (PPD), modified plaque index (mPI)) and marginal bone loss (MBL, marginal bone level change between follow-up and occlusal loading) around cemented and screw-retained posterior single crowns on tissue-level implants. The study was a retrospective cohort study with up to 4 years (mean 2.5 years) follow-up. Patients with either cemented or screw-retained crowns in posterior regions were included. Implant survival, technical complications, BOP, PPD, mPI, MBL, biologic complications (peri-implant mocositis and peri-implantitis) were evaluated. Mann-Whitney U test was used to test the difference between the screw-retained group (SG) and cemented group (CG). 176 patients (SG: 94, CG: 82) were included. The implant survival rates were 100% in SG and 98.8% in CG. Prosthetic screw loosening was found in 8 restorations (8.7%) at follow-up visit. Peri-implant mucositis rate was significantly higher in the SG group (42.1%) than that in the CG group (32.2%) (P = 0.04). Six patients (6.38%) in the screw-retained group and 5 patients (6.10%) in the cemented group were diagnosed with peri-implantitis, the difference did not reach statistical significance (P>0.05). No significant difference of PPD, mPI and MBL were found between two groups (P = 0.11, 0.13 and 0.08, respectively). High implant survival rates were achieved in both groups. Cemented single crowns on tissue-level implants showed comparable peri-implant conditions in comparison with two-piece screw-retained crowns. Well-designed prospective cohort or randomized controlled clinical trials with longer follow-up are needed to confirm the result.

Highlights

Dental implants have become a routine treatment strategy in partial and edentulous patients [1]
Cemented prostheses were considered to be accompanied by higher biologic complication rates, while screw-retained prostheses were accompanied by higher technical complication rates[6, 7]
No significant difference of age, gender, implant location, implant diameter, implant length, follow-up, history of periodontitis, opposing occlusion and healing protocol were found between two groups

Summary

Introduction

Dental implants have become a routine treatment strategy in partial and edentulous patients [1]. One of the important clinical decisions in implant treatment was the choice of implant/ abutment connection type connecting restorations and implant abutments: cemented or screw-retained prostheses? Screw-retained prostheses were first introduced for full-arch implant-supported prostheses in edentulous patients[4]. Cemented prostheses were widely applied due to the ease of restorability during the 2000’s [5]. Both screw-retained and cemented retention have been used in connection of implant-supported single crowns, fixed partial denture and full arch prostheses. Larger marginal micro-gaps were found around cemented prostheses than those around screw-retained prostheses, which could lead to more biofilm accumulation and higher prevalence of peri-implant infections It was reported that residual cement might lead to peri-implant infection, especially when cement margins were relatively deep[9]

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