Clinical abstract: proximal contact loss

This article was first published in the ADA's News Bulletin, April 2023.

An abstract by Dr Scott Davis for the Dental Instruments, Materials and Equipment Committee on: Liang CH, Nien CY, Liang HL, Hsiao CC, Peng YC, Hsu KW. Recurrence Rate of Proximal Contact Loss Between Implant Restorations and Adjacent Teeth After Proximal Contact Repair: A Retrospective Study. Int J Oral Maxillofac Implants. 2022;37:579-585.

Proximal contact loss (PCL) between implant- supported fixed dental prostheses (FDPs) and adjacent teeth has been reported as a common complication of implant therapy. The prevalence of PCL and its potential risk factors have been extensively studied. However, few studies have discussed the recurrent PCL after intervention to restore the proximal contacts. Thus, this retrospective study aimed to evaluate the recurrence rate of PCL and its potential risk factors.

Materials and methods

This study included patients who had: (1) received implant- supported FDPs in the posterior region from May 2002 through to September 2018; (2) experienced PCL between implant restorations and adjacent teeth and received a contact repair treatment (first intervention); and (3) routinely returned for recall examination with an interval of 6 to 12 months between November 2002 and December 2020. This study included 41 patients (with 45 implants in the posterior region). Recurrent PCL was recorded and evaluated during routine follow-ups. The recurrence rates and time were measured. The potential influential factors of PCL were also assessed. Fisher exact test, T test, univariate logistic regression analyses, and multivariate logistic regression model were utilised to identify factors influencing PCL.

Results

The recurrence rates of mesial PCL were high (> 50%) and the recurrence time became progressively rapid after each repair (5, 3.2, and 2.2 years). Implants with the first PCL recurrence were more likely to be splinted than those implants without recurrence (54.5% vs 18.8%; P = .032). In addition, patients with the first recurrence were slightly older than those without recurrence (55.8 vs 50.1 years; P = .087). Age, implant restoration (splinted vs single), frequent use of interdental brushes, and time to first complaint were the candidate factors associated with recurrent PCL in the univariate logistic regression analysis. The multivariate logistic regression model revealed that only splinted implant restoration was independently associated with a higher risk of recurrence (odds ratio 4.99; 95% confidence interval 1.02-24.31; P = .047).

Conclusion

The recurrence rates of mesial PCL were high and associated with the splinted-type design. Also, the recurrence time of PCL accelerated after each repair. Therefore, routine follow-up monitoring PCL and carefully assessing patient compliance after implant therapy are recommended. Also, selection of retrievable restorations such as screw retained restorations or cementation with interim cements provides the advantage of facilitating repair of an open contact. In addition, use of an occlusal retainer may help to prevent or reduce PCL.