Clinical outcomes of conversion prosthesis in immediately loaded implants: A retrospective study.

Purpose: The primary objective of this retrospective study was to evaluate the survival outcomes of immediately loaded acrylic resin complete arch fixed implant-supported prosthesis (CAFIP) fabricated from the denture conversion protocol. The secondary objective was to evaluate the early implant survival outcomes associated with these prostheses.

Material and methods: A retrospective chart review was conducted to study the clinical outcomes data of immediately loaded conversion prostheses and immediately loaded implants. All patients who had been treated with immediately loaded acrylic resin CAFIP using the denture conversion protocol over a 9-year period were included in the study. All dentures were fabricated by conventional processing using compression molded or injection molded techniques. These patients were treated by numerous clinicians but adhering to the same protocol, over the entire 9-year follow-up period. Clinical outcome data related to the number of early fractures during the initial implant healing period of 4 months, early implant failures, late fractures (after 4 months), late implant failures (after 4 months), technical complications, number and type of implants placed, the arch in which the implants and prosthesis were placed and the type of opposing dentition were recorded and analyzed. A p-value < 0.05 was determined to be statistically significant.

Results: A total of 153 prostheses (97 in maxilla, 56 in mandible) in 117 patients (60 males, 57 females) and 768 implants (298 in maxilla, 470 in mandible) were evaluated. All conversion prostheses were followed up for a minimum of 4 months (range of 4-20 months). There were a total of 15 implant failures yielding a survival rate of 98% survival rate during the observation period with the conversion prostheses. Only 3 of the failed implants were associated with a failure (crack or fracture) of the conversion prosthesis (maxilla) during the 4-month healing period. There were a total of 9 conversion prostheses with cracks or fractures during the 4-month healing period (early critical complication), yielding a complication-free survival rate of 94.1%. There were 6 additional early noncritical prosthetic complications such as tooth debonding or chipping during the 4-month period. Only the early critical prosthetic complication rates comparing maxilla and mandible were statistically significant (p = 0.037).

Conclusions: The findings from this retrospective study revealed a high early survival rate for dental implants (98%) and for the immediately loaded acrylic resin CAFIP fabricated from the denture conversion protocol (94%). There were minimal additional implant failures and noncritical complications related to the conversion prosthesis. The denture conversion protocol is a simple evidence-based technique and serves as an excellent and predictable method for the immediate loading of dental implants.