Effect of Crown to Implant Ratio and Anatomical Crown Length on Clinical Conditions in a Single Implant: A Retrospective Cohort Study

• Published in: Clinical implant dentistry and related research Vol. 17; no. 4; pp. 724 - 731
• Main Authors: Sun, Shan-Pao, Moon, Ik-Sang, Park, Kwang-Ho, Lee, Dong-Won
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.08.2015
• Subjects: Adult; Aged; Cohort Studies; crown-to-implant ratio; Crowns; Dental Implants; Dental Prosthesis Design - methods; Female; Humans; Male; marginal bone loss; Middle Aged; Retrospective Studies; single implant; crown-to-implant ratio; marginal bone loss; single implant
• ISSN: 1523-0899; 1708-8208; 1708-8208
• DOI: 10.1111/cid.12175

Purpose The aim of this retrospective cohort study was to evaluate the long‐term influence of the crown‐to‐implant (C/I) ratio and anatomical crown length on clinical conditions around Astra single dental implants placed in the premolar and molar regions. Materials and Methods Seventy‐six subjects were selected from patients who had been treated with single Astra implants for replacement of missing premolars and molars. The peri‐implant marginal bone level change was assessed 1 year after functional loading and 6 years after functional loading. To predict the peri‐implant marginal bone level change using clinical and radiographic data, a multiple linear regression model was applied. The Wilcoxon rank sum test was used to analyze difference median in technical complications. Results The C/I ratio and anatomical crown length were not associated with peri‐implant marginal bone loss or changes in the bone level at 6 years (p = .48, p = .31). However, the modified plaque index, modified sulcus bleeding index, and smoking status influenced the peri‐implant marginal bone loss (p < .05, r2 = 0.54). In addition, the patient with technical complication group did show significantly increased anatomical crown length (p < .05) Conclusions The higher C/I ratio and anatomical crown length did not increase the risk of peri‐implant marginal bone loss during 6 years of functional loading. In addition, higher anatomical crown lengths are associated with higher technical complications.