Flapless surgery and immediately loaded implants: a retrospective comparison between implantation with and without computer-assisted planned surgical stent.

OBJECTIVES: Computer planned flapless surgery and immediate loading are the most recent topics in implantology. One new computer-planned implant system uses a three-dimensional parallelometer able to transfer the implant position from the virtual project to the master model. The aim of this study was to verify if the new medical device gives an advantage in term of implant failures and/or crestal bone remodeling.

MATERIAL AND METHODS: A retrospective study was planned to analyze a series of 193 immediately loaded fixtures inserted by means of flapless surgery. From those sixty six implants were inserted with computer planning whereas 127 were inserted "free-hand". Several variables related to patient, anatomy, implant, surgery and prosthesis were investigated. To detect the clinical outcome implant' failure and peri-implant bone resorption were considered. Kaplan-Meier algorithm and Cox regression were then performed to detect those variables statistically associated with the clinical outcome.

RESULTS: Implant length and diameter ranged from 10 to 16 mm and from 3.75 to 6.0 mm, respectively. Implants were inserted to replace 46 incisors, 30 cuspids, 75 premolars and 42 molars. The mean follow-up period was 15 months. Seven implants were lost (survival rate 96.4%) but no studied variable has a statistical impact on failures. On the contrary, implants inserted in sites with completed bone healing, wide diameter fixtures and implants inserted in totally edentulous jaw had a significantly lower crestal bone resorption. The other variables (age, gender, upper/lower jaws, tooth site, implant' type and length, number of prosthetic units antagonist condition) did not have impact on crestal remodeling.

CONCLUSION: Computer-planned and cast model transferred implantology is a reliable technology that provides a slightly higher clinical outcome than "free hand" technique at least in healed sites, wider implants and totally edentulous jaws.