Risk Factors Associated With Infraposition of Implant Supported Single Crowns in the Anterior Maxilla

Losing a tooth in the front part of the upper jaw can affect both appearance and the ability to bite and chew. Treatment to replace missing teeth is therefore often required. Such treatment may be burdensome for the individual and can involve substantial costs for both the patient and society. A common treatment option is placement of a titanium screw (dental implant) in the jawbone. After a healing period, the implant is restored with a crown designed to resemble a natural tooth.

Replacement of missing teeth with dental implants in the anterior maxilla can be particularly challenging. Over time, the crown of an implant may appear shorter than the adjacent natural teeth. This occurs because natural teeth may continue to change position throughout adulthood, whereas dental implants remain fixed within the bone. As a result, the implant-supported crown may appear to sink relative to neighboring teeth, a phenomenon referred to as infraposition. The prevalence of infraposition and the factors contributing to its development are not yet fully understood.

The aim of this study is to determine the frequency and extent of infraposition and to identify potential contributing factors in individuals treated with a single implant-supported crown in the anterior maxilla. The study also aims to evaluate the aesthetic outcome after treatment from both the patient and the clinician perspective.

The study hypothesis is that infraposition occurs in a clinically relevant proportion of patients and that certain factors, such as age at implant placement or individual dental characteristics, may increase the likelihood of its occurrence. It is further hypothesized that infraposition of the implant-supported crown may influence aesthetic appearance and that these changes may be perceived differently by patients and dental professionals.

Through longitudinal follow-up and comparison of repeated digital scans, the study seeks to improve understanding of the occurrence of infraposition, its contributing factors, and its potential impact on the aesthetic outcome of implant-supported crowns over time.