Guided-welded approach planning using digital scanning technology for combined screw- and conometric-retained implant-supported maxillary prosthesis.

AIM: The goal of this case series was to evaluate the clinical outcome at the 2-year follow-up of immediately loaded combined screw- and conometric-retained implant-supported full-arch restorations virtually planned using digital scanning technology. MATERIALS AND METHODS: This series included 12 patients presenting hopeless teeth in the maxilla treated with computer-guided flapless implant placement. A total of 72 implants were inserted. All implants were immediately loaded with a complete-arch restoration supported by an intraorally welded framework. Digital scanning technology was used to virtually plan a combined screw and conometric retention of the frameworks. Clinical parameters were assessed at 1 week and at 1, 3, 6, 12, and 24 months follow-up. RESULTS: The survival rate after 2 years was 98.6%, as one implant failed during the osseointegration period. No major prosthetic complications were observed such as issues with mobility, unscrewed abutments, disconnected conometric copings, and prosthetic fracture. Only one patient registered the chipping of a prosthesis. CONCLUSION: Based on the results of the present study, the use of combined screw and conometric retention for fixed immediate restorations properly planned using digital scanning technology seems to be a viable treatment alternative to screw or conometric retention alone for immediately loaded rehabilitations.

Conometric retention for complete fixed prosthesis supported by four implants: 2-years prospective study.

OBJECTIVE: The aim of this study was to verify the reliability of a conometric system for a fixed retention of complete prostheses (CPs) on four implants followed for 2 years. MATERIAL AND METHODS: Twenty-five patients received four implants and only one CPs for a total of 100 implants followed. Each prosthesis was supported by four implants. An immediate loading surgical protocol was used. The CPs were provided to be fixed to conometric abutments without prostheses removal by the patients, to test this retention for a fixed instead of a removable rehabilitation. Clinical and radiographical parameters were assessed at the yearly follow-up visit. A follow-up of 2 years was observed for each patient. Moreover, biological and technical complications were recorded. Changes overtime of clinical and radiographic parameters were analyzed as well as the satisfaction degree for each patient. RESULTS: No patient was classified as "dropout." The following results were observed after 2 years of follow-up: all the implants supporting the 25 CPs completed the follow-up examination. No implant, reconstruction, and abutment failure were recorded; therefore, the prosthetic survival was 100% for all the abutments and restorations. No significant differences in biological indexes were observed when compared with the baseline. No significant change of the mean marginal bone level (MBL) was found between the baseline and the last follow-up. No loss of retention was recorded for the CPs. No technical complications referred to abutments and frameworks were observed: a prosthetic survival rate of 100% can be recorded. Mucositis was recorded for two implants and successfully treated with interceptive supportive therapy. No significant differences (P < 0.05) were found between plaque index and MBi parameters at baseline and after 2 years of function. Similar results were recorded for the mean probing pocket depth Index at baseline (1.2 mm with SD of 0.3 mm) and after 2 years of function (1.2 mm with SD of 0.2 mm). CONCLUSIONS: The present implant-supported conometric retention system can be used to give a fixed retention to a CPs supported by four implants immediately loaded. Furthermore, costs reduction and simplified treatment procedures were provided by such a clinical approach.

Five-year prospective study on conometric retention for complete fixed prostheses.

PURPOSE: To evaluate the reliability of a conometric system for fixed retention of complete prostheses (CPs) on four implants after 5 years of function. MATERIALS AND METHODS: Twenty-five patients with a completely edentulous mandible received four implants supporting a CP. A total of 100 implants were immediately loaded with CPs on conometric abutments. A follow-up of 5 years was observed for each patient. Outcome measures were prosthesis and implant success, complications, probing pocket depth changes, marginal bleeding and plaque changes, and patient satisfaction. RESULTS: One patient dropped-out. In total, 96 implants supporting the 24 CPs completed the follow-up examination at 5 years. No implant failed. Two framework fractures occurred after 4 and 5 years of function. No loss of retention was recorded for the CPs. Mucositis was recorded for two implants after 1 year of prostheses function for two patients, for one implant after 3 years and for two implants after 4 years in different patients and successfully treated with interceptive supportive therapy. No significant differences were found between Plaque Index (PI) at baseline and after 2 years (P = 1.0); similar findings were calculated between PI at baseline and after 5 years (P = 0.6) of function. At baseline, after 2 and after 5 years, respectively, 69%, 64% and 56% of implants showed a PI of 0; 31%, 36% and 44% of implants showed a PI between 1 and 3. Modify Bleeding Index (MBI) was not significantly different both between baseline and after 2 years of function (P = 1.0) and between baseline and 5 years of function (P = 0.5). At baseline, after 2 and after 5 years, respectively, 69%, 65% and 61% of implants showed a MBI of 0; 27%, 28% and 29% of implants showed a MBI of 1; and 4%, 7% and 10% of implants showed a MBI of 2. The mean probing pocket depth was 1.2 ± 0.4 mm at baseline, 1.2 ± 0.4 mm after 2 years and 1.4 ± 0.5 mm after 5 years of function. The differences were not statistically significant between baseline and 2 years (P = 1.0) and between baseline and 5 years (P = 0.1). From the patient satisfaction questionnaire, 85% percent of patients were satisfied from both aesthetic and functional points of view after 5 years of conometric prostheses function. CONCLUSIONS: The present implant-supported conometric retention system can be used to give fixed retention to a CP supported by four implants. An adequate metal framework should be provided to the definitive restoration in order to avoid fractures in the long term.