title: Marginal bone loss around dental implants with and without microthreads in the neck: A systematic review and meta-analysis.
abstract: BACKGROUND
  Whether microthreads in the crestal portion can reduce the amount of marginal bone loss (MBL) around implants has not yet been determined.
  
  
  OBJECTIVE
  The purpose of this systematic review was to investigate the marginal bone loss around dental implants with and without microthreads in the neck.
  
  
  METHODS
  This review was based on the PRISMA guidelines. An electronic search with no restrictions on language was performed from inception to August 19, 2015, in PubMed, Cochrane Central Register of Controlled Trials, EMBASE, Web of Sciences, and AMED (Ovid) databases. A manual search was also performed. Randomized clinical trials (RCTs) that compared the MBL between implants with and without microthreads in the neck were included. Qualitative synthesis and meta-analysis were performed. MBL was measured by using the mean difference (MD). Review Manager v5.3 software was used for meta-analysis (α=.05).
  
  
  RESULTS
  Five articles were included in the qualitative synthesis, and 3 articles were included in the meta-analysis. Four studies found that a microthread design can significantly reduce MBL under functional loading, whereas 1 study found no signiﬁcant difference. The homogeneity test of meta-analysis confirmed acceptable heterogeneity among the 3 studies (I2=0.49). A random-effects model was used. The result shows that MBL around implants with microthread design can be reduced signiﬁcantly (P=.030; MD: -0.09; CI: -0.18 to -0.01).
  
  
  CONCLUSIONS
  Meta-analysis showed that microthread design in the implant neck can reduce the amount of MBL; however, RCTs included in the review were few and the difference was small. In clinical practice, an implant with a roughened surface and microthreaded neck could be selected to maintain bone level.
authors.affiliation: Associate Professor, Department of Implantology, Xuzhou Stomatological Hospital, Xuzhou City, China.
authors.forename: Wenzhi
authors.initials: W
authors.lastname: Niu
authors.affiliation: Professor, Department of Implantology, Xuzhou Stomatological Hospital, Xuzhou City, China.
authors.forename: Penglai
authors.initials: P
authors.lastname: Wang
authors.affiliation: Resident, Department of Implantology, Xuzhou Stomatological Hospital, Xuzhou City, China.
authors.forename: Shaoyue
authors.initials: S
authors.lastname: Zhu
authors.affiliation: Associate Professor, Department of Periodontology, Xuzhou Stomatological Hospital, Xuzhou City, China.
authors.forename: Zongxiang
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Professor, Department of Prosthodontics, Dental School, University of Shandong, Jinan City, China. Electronic address: 513240446@qq.com.
authors.forename: Ping
authors.initials: P
authors.lastname: Ji
mesh_terms: D016301:Alveolar Bone Loss / Q000209:etiology*; D003758:Dental Implantation, Endosseous / Q000009:adverse effects; D015921:Dental Implants / Q000009:adverse effects*; D006801:Humans
chemical_list: D015921:Dental Implants