OBJECTIVES: To report the clinical, radiographic, aesthetic and patient-reported outcomes after placement of a newly developed Narrow-Diameter Implant (NDI) in patients with congenitally Missing Lateral Incisors (MLIs).

MATERIALS AND METHODS: Patients with MLIs with a mesio-distal distance between the canine and the central incisor of 5.9-6.3mm received a dental implant with a diameter of 2.9mm (Test), while a diameter of 3.3mm (Control) was used when the distance was 6.4-7.1mm. After healing, a cement-retained bi-layered zirconia crown was fabricated. At the 1-year follow-up (T2), implant survival rate, marginal Crestal Bone Level (CBL) changes, biological and technical complications were registered. The aesthetic outcome was assessed by using the Copenhagen Index Score, and the patient-reported outcomes were recorded using the OHIP-49 questionnaire.

RESULTS: One-hundred patients rehabilitated with 100 dental implants Ø2.9mm (n = 50) or Ø3.3mm (n = 50) were included. One Ø3.3mm implant was lost and 7 patients dropped out of the study, yielding an implant survival rate of 99% (p = 1.000). At T2 a CBL of -0.19 ± 0.25 mm (Test) and -0.25 ± 0.31 mm (Control) was detected, with no statistically significant difference between the groups (p = 0.342). Good to excellent aesthetic scores (i.e. 1-2) were recorded in most of cases. Technical complications (i.e. loss of retention, abutment fracture, chipping of veneering ceramic) occurred once in three patients with no statistically significant difference between the groups (p > 0.05). OHIP scores did not differ significantly at follow-ups between groups (p = 0.110).

CONCLUSION: The use of Ø2.9mm diameter implants represents as reliable a treatment option as Ø3.3mm implants, in terms of CBL changes, biological and technical complications. Favorable aesthetics and patient-reported outcomes were recorded for both groups.