Polizzi Giovanni

BACKGROUND: As a complement to the earlier reported 3-year results from a prospective multicenter study of immediate and delayed placement of implants into fresh extraction sockets, the 5-year results are reported. PURPOSE: The purpose of this 5-year report was to evaluate the immediate and long-term success of implants placed into fresh extraction sockets, with respect to implant size and type, bone quality and quantity, implant position, initial socket depth, and reason for tooth extraction. MATERIALS AND METHODS: This paper presents the 5-year results of the original 12 centers that participated with 143 consecutively included patients. A total of 264 implants were placed either immediately after tooth extraction or after a short soft-tissue healing time (3-5 weeks). The patients were divided into five subgroups, depending on the type of insertion method used. RESULTS: The outcome demonstrated that the cumulative implant survival rate after 5 years of loading has not changed and remains 92.4% in the maxilla and 94.7% in the mandible. No difference in failure rates can be seen between the groups when relating the failures to insertion method. CONCLUSION: This prospective study demonstrated that placing Brånemark implants into fresh extraction sites can be successful over a period of 5 years of loading. One of the outcomes of the study shows that there is a clinical correlation between implant failure and periodontitis as a reason for tooth extraction, even if it is difficult to give it a casual association. It can be hypothesized that periodontitis affected tissues might have a negative local influence because of the presence of infrabony defects that could possibly increase the gap between bone and implant or jeopardize achievement of primary stability.

Diagnosis and implant treatment planning in cases where hopeless teeth need to be extracted and immediately replaced with implants are more difficult and challenging than a standard multistage approach. Software and CAD/CAM technologies are becoming increasingly common to help clinicians in their practices. They use data from CT scans of the patient and of a radiographic guide for virtual implant treatment planning on a computer and the successive production of a surgical template, which will facilitate surgery and enable fabrication of a prosthesis to be delivered immediately. These procedures, however, are well-established only for patients who are already edentulous in the area to be treated; they are difficult to apply to a patient whose desire is to keep the hopeless dentition until the day of implant surgery to avoid having to wear a removable partial or complete denture. This article describes the advantages and the technique for fabrication of a novel 2-piece radiographic guide that, in conjunction with CAD/CAM technology, will help clinicians in the diagnosis and implant treatment planning of patients who want to retain their teeth until surgery.

BackgroundVariable-thread tapered implants are designed to achieve high primary stability in demanding situations, such as fresh extraction sitesor regions of low bone quality. In addition to their specialized thread design, these implants can be placed at torques up to 70 Ncm.Continued investigation of these implants placed in challenging situations is necessary to evaluate their long-term survival and clinicalperformance.Aim/HypothesisThe main objective of this retrospective analysis was to evaluate the bone remodeling as a measure of safety and efficacy in patientindications with single crowns or partial bridges restored on variable-thread tapered implants after up to 6.7 years of function.Materials and MethodsPatients with single or partial tooth restorations, who received at least one variable-thread tapered implant (NobelActive, NobelBiocare) between January 2008 and July 2009 were retrospectively evaluated. Bone quality was assessed (Lekholm and Zarb (1985))at time of surgery. Marginal bone levels (MBL) were measured from radiographs at baseline (implant insertion), at 1-year follow-up,and at last follow-up (mean 6.0 years, range 4.7 - 6.7 years). Marginal bone remodelling (MBR) was calculated for paired radiographsfrom baseline to 1-year follow-up, baseline to 6-year follow-up, and from 1-year to 6-year follow-up. Secondary measures reportedinclude presence of plaque, Jemtu2019s papilla index, and implant stability. Statistical analysis was performed with the software SPSSStatistics 24 (IBM, Armonk, NY, USA).ResultsTwenty-four patients (14 female, 10 male; mean age 58 u00b19.9 years) received 35 implants. 94% of implants were placed in the maxilla(n=33). 20 implants were placed in extraction sockets and 15 in healed sites. 32 implants were tightened to torques >35 Ncm (mean59.6 u00b113.2 Ncm). Bone quality was reported as 2 (n=9), 3 (n=18), and 4 (n=8). Graft material was used at time of implant insertion for9 of the 20 extraction sites. Sinus lift was performed in 3 implant sites. All patients received an acrylic provisional prosthetic and 23received final prosthetics at a mean of 1.5 years after implant insertion. Mean MBL were -0.54 u00b10.62 mm, -1.04 mm u00b10.68 mm, and-1.04 u00b10.98 mm at baseline, 1-year follow-up, and 6-year follow-up, respectively. Mean MBR was -0.47 u00b10.64 mm, -0.38 u00b11.22 mm,and -0.11 u00b11.01 mm from baseline to 1-year, baseline to 6-years and 1-year to 6-years, respectively. No adverse events werereported and all implants were stable at final follow-up.Conclusions and Clinical implicationsThis 6-year retrospective analysis showed that variable-thread tapered implants show good long-term outcomes, in terms of survival,stability and MBR, when placed in demanding situations such as extraction sockets or low density bone sites (i.e. in the maxillaryposterior area). Additionally, high insertion torques (>35 Ncm) could be achieved with this protocol with only minor MBR from baselineto 1-year follow-up and stable bone levels from 1-year to up to 6 years of function.