IMMEDIATE LOADING OF OCCLUDING DEFINITIVE PARTIAL FIXED PROSTHESES VERSUS NONOCCLUDING PROVISIONAL PROSTHESES: 10-YEAR POST-LOADING RESULTS FROM A MULTICENTRE RANDOMIZED CONTROLLED TRIAL

PURPOSE. To compare the clinical outcomes of dental implants restored with definitive occluding partial fixed prostheses within one week after implant placement versus immediate loading with non-occluding provisional restorations replaced by definitive prostheses after four months.

MATERIALS AND METHODS. Forty partially edentulous patients treated with one to three dental implants, of length at least 8.5 mm and width 4.0 mm and inserted with a torque of at least 35 Ncm, were randomized to two groups of 20 patients each. Patients from one group received one definitive screw-retained metal-ceramic prosthesis in occlusion within one week after placement (occlusion group), while those in the other group received one non-occluding provisional acrylic reinforced prosthesis within 24 hours after implant placement (non-occlusion group); after four months, provisional prostheses were replaced by definitive ones. The follow-up for all patients was 10 years post-loading. Outcome measures were prosthesis and implant failures, any complications, peri-implant marginal bone level changes, aesthetics, patient satisfaction, chairside time and number of visits to the clinic from implant placement to delivery of definitive restorations.

RESULTS. At 10-year follow-up, nine patients had dropped out, four from the non-occlusion group and five from the occlusion group. Two implants from the latter, along with their definitive prostheses, failed early (difference in proportions = 0.1; 95% CI = -0.08 to 0.26; P = 0.487). Five patients from the occlusion group were affected by seven complications versus five patients (five complications) in the non-occlusion group, with no statistically significant difference in proportions (difference in proportions = -0.01; 95% CI = -0.28 to 0.26; P = 1). Ten years after loading, patients subjected to occlusal loading lost an average of 0.94 mm of peri-implant bone versus 0.90 mm in patients initially restored with non-occluding provisional prostheses. There were no statistically significant differences in marginal bone level changes between the two groups (mean difference = 0.17 mm; 95% CI -0.25 to 0.58; P = 0.416). Likewise, there were no significant differences in either pink aesthetic scores (5.32 versus 4.45; P = 0.496) or patients’ satisfaction with aesthetics (Fisher’s exact probability test P = 1), and all patients in both groups declared being fully satisfied with function. However, patients immediately loaded with a definitive prosthesis required significantly less chairside time (mean difference -38.00; 95% CI -58.96 to -17.04; P = 0.001) and fewer visits (mean difference -2.15; 95% CI -2.77 to -1.53; P <0.001).

CONCLUSIONS. Although unable to provide a definitive conclusion due to the insufficient sample size, the results do suggest that immediate loading in occlusion with definitive partial fixed prostheses is not only a viable therapeutic option for patients, but requires fewer appointments and less chairside time.