Prospective cohort study to evaluate narrow diameter implants for the restoration of a missing maxillary lateral incisor in patients with a cleft palate: Five-year results.

Statement of problem: The maxillary lateral incisor is often congenitally missing in patients with a cleft palate. The congenital cleft presents the practitioner with challenges including quantity and quality of bone, a surgically managed cleft correction, and limited clinical space.

Purpose: The purpose of this investigation was to calculate the 5-year success and survival rate of narrow-diameter implants used to restore a missing lateral incisor in patients with a cleft palate.

Material and methods: Fourteen study participants with a cleft palate and a missing maxillary lateral incisor were enrolled based on established criteria. Seventeen narrow-diameter implants (AstraTech OsseoSpeed 3.0S and OsseoSpeed TX 3.5 mm) were placed using a 2-stage protocol and restored with a custom titanium abutment and a cement-retained crown. Clinical and radiographic examinations were performed annually for 5 years. Four probe depth measurements were measured and evaluated using an analysis of covariance (ANCOVA) with Tukey-Kramer multiple comparisons tests. Radiographic marginal bone loss was measured annually using a digital subtraction technique and evaluated with ANCOVA, and the least square mean was derived. The restoration was evaluated using Pink (PES) and White (WES) Esthetic scores.

Results: Regarding probing depth measurements, a significant variance was found between the 4 locations (P<.001), and a linear effect of year was also found (P=.005). The multiple comparisons tests showed the mean buccal probe depth was lower compared with the mean at each of the other 3 locations (P≤.039) from baseline to 5-year follow-up. The least square mean ±standard deviation of the marginal bone loss over the 5-year entire study was 0.55 ±0.088 mm. Regarding prosthesis evaluation, the mean score for PES was 6.15 and 6.63 for the WES with a maximum score of 10. The level for clinical acceptance was set at a total score of 6. To meet the criteria for success over the 5-year period, no more than 2.3 mm of total bone loss was acceptable. The number of implants that met the criteria for success at 5 years was 92%. Regarding survival, the number of implants still in place, functional, and asymptomatic at 5 years was 100%.

Conclusions: Based on the findings, the peri-implant soft tissue probe depths exhibited significant change during the 5-year investigation. Regarding esthetic outcomes, single tooth NDI for replacing a lateral incisor in the cleft patient is a clinically acceptable treatment. Narrow-diameter implants may be a reliable treatment for replacing a missing lateral incisor in patients with a cleft at 5-year follow-up with an implant survival rate of 100% and a success rate of 92%.