title: Mathematical evaluation of the influence of multiple factors on implant stability quotient values in clinical practice: a retrospective study.
abstract: OBJECTIVE
  The objective of this study is to mathematically evaluate the influence of multiple factors on implant stability quotient values in clinical practice.
  
  
  METHODS
  Resonance frequency analysis was performed at T1 (measured immediately at the time of implant placement) and at T2 (measured before dental restoration) in 177 patients (329 implants). Using a multivariate linear regression model, we analyzed the influence of the following eleven candidate factors: sex, age, maxillary/mandibular location, bone type, immediate/delayed implantation, bone grafting (presence or absence), insertion torque, I-/II-stage healing pattern, implant diameter, implant length, and T1-T2 time interval.
  
  
  RESULTS
  The following factors were identified to significantly influence the implant stability quotient (ISQ) values at T1: insertion torque, bone grafting, I-/II-stage healing pattern, immediate/delayed implantation, maxillary/mandibular location, implant diameter, and sex. In contrast, the ISQ values at T2 were significantly influenced only by three factors: implant diameter, T1-T2 time interval, and insertion torque.
  
  
  CONCLUSIONS
  Among the eleven candidate factors, seven key factors were found to influence the T1-ISQ values, while only three key factors influenced the T2-ISQ values. Both T1 and T2-ISQ values were found to be influenced by implant diameter and insertion torque. T1 was influenced specifically by the sex of the patient, the location (maxillary or mandibular), the implantation mode (immediate/delayed implantation), the healing stage, and the absence or presence of bone graft materials.
authors: Department of Oral Implantology and Prosthetic Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute, VU University Amsterdam and University of Amsterdam, Amsterdam, Nord-Holland, the Netherlands.
authors: Hairong
authors: H
authors: Huang
authors: Department of Oral Implantology and Prosthetic Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute, VU University Amsterdam and University of Amsterdam, Amsterdam, Nord-Holland, the Netherlands.
authors: Daniel
authors: D
authors: Wismeijer
authors: Best & Easy Dental Clinic, Hangzhou, Zhejiang Province, People's Republic of China.
authors: Xianhong
authors: X
authors: Shao
authors: Department of Oral Implantology and Prosthetic Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute, VU University Amsterdam and University of Amsterdam, Amsterdam, Nord-Holland, the Netherlands.
authors: Gang
authors: G
authors: Wu
keywords: delayed implantation; dental implant; immediate implantation; implant stability quotient; insertion torque; resonance frequency analysis