Marginal Bone Preservation in Single-Tooth Replacement: A 5-Year Prospective Clinical Multicenter Study

BackgroundFew long-term studies are available comparing immediate and conventional loading protocols of implant-supported single-tooth replacement. PurposeThe aim of the present randomized controlled clinical trial was to evaluate prospectively the 5-year clinical and radiological outcome of immediate functional loading implants used in single-tooth replacement. Materials and MethodsOne hundred fifty-one subjects, who required single-tooth rehabilitation in the area from position 15 to 25 and from 35 to 45, were enrolled in eight private clinics in Italy. A randomization protocol was applied to allocate the implants in three treatment groups: one control group and two test groups. In the control group, implant placement was performed according to a conventional drilling procedure, and the implants were submerged for 3 months before abutment connection and loading. Implants allocated in the test group 1 and 2 followed an immediate functional loading protocol. While in test group 1, implant placement was performed according to conventional drilling procedure, in test group 2, a modified implant installation procedure (osteotome technique) was applied. Clinical and radiographic examinations were performed during the 5-year follow-up, and technical and biological complications were registered. ResultsAlthough four implants (three in the test group 2 and one in the test group 1) were lost in the immediate functional loading groups in the first year of follow-up, no further implant loss occurred in any of the treatment groups in the following monitoring period up to 5 years. No significant differences on marginal bone level changes were observed between the treatment groups. About 52% of all implants showed bone gain in the period from 1-year to 5-year follow-up. The percentage of all implants that in the same interval of time showed bone loss was about 28%. Although few technical complications were recorded in the period of time up to 5 years, implants showing biological complication were 5.7%. ConclusionIt is suggested that implants installed with a conventional installation technique together with an immediate functional loading protocol may be considered as a valid treatment alternative in a long-term perspective when used in a single-tooth replacement in an esthetic area.