Crestal Bone Remodeling around Platform Switched, Immediately Loaded Implants Placed in Sites of Previous Failures

Abstract

The possibility to insert immediately-loaded implants in post-extraction sites where previously inserted implants had failed and had never received a prosthesis has not been sufficiently studied to the present day. Only few articles in the literature address this problem. The aim of the present study was to evaluate crestal bone remodeling around implants with a platform-switched design inserted and loaded immediately after the failure ofthe previous implants. This study has a follow-up of 36 months. Failed implants that had never received a prosthesis have been removed in 68 patients. In the present study 10 patients, whose bone crest measured at least 8 mm in width, were selected and 16 immediately loaded implants with a platform-switched design and a sandblasted and acid etched SLA surface, (Winsix®, Biosaf sri, Italy) were placed. Statistically significant differences were observed in crestal bone remodeling between 12 and 36 months (p<0.05) and between 24 and 36 months (p<0.001), although no statistically significant differences were found between 12 and 24 months (p>0.05). The values of periodontal indices have sometimes been borderline, although they returned normal later on. The cumulative success-rate of all the 16 implants inserted was of 93.75%, while the survival rate was 100%. Results show that immediately loaded platform-switched implants are a practicable solution for the rehabilitation of sites of early failed implants.Many studies describe the success of implants in time (1-4), but only a small number investigate the causes of implant failure, while studies describing the possibility to insert new implants used for a fixed prosthetic rehabilitation in the site of implants previously failed, (for various reasons) are even fewer (5-6). Very often in the past, patients who had suffered implant failure were treated with an overdenture to avoid additional implant surgery which was not predictable at that time. Only one article treated the insertion of implants in sites where previously inserted implants had failed, but the surgery was performed after 9 to 12 months after the removal of the failed implants (7). Today clinicians may choose between various implant designs, such as macro-implants, short implants, which allow implant insertion where bone volume is insufficient. It has been proven that in conventional dental implants, consisting in a fixture and an abutment, the peri-implant bone resorbs between 1 to 2 mm after -prosthetic loading, when the implant platform is positioned at a crestal level(8). Some investigators have demonstrated that when the implant platform is positioned at a sub-crestallevel, bone resorption increases (9). According to certain authors, crestal bone remodeling is caused by masticatory stress (10). Another hypothesis suggests that soft tissue inflammation may cause the crestal bone to resorb (11). Some researchers have demonstrated that in all two-piece implant systems there is a gap between the implant and the abutment. The gap measures approximately 10 urn and is respo...

A systematic review and meta-analysis of the survival rate of implants placed in previously failed sites

“…Replacement implants were followed for less than 1 year in two studies, 23,25 and for at least 1 year in seven studies. 18,19,20,21,10,27,24 In of one study, the observation period of replacement implants was not reported 26 (Table 2).…”

“…Only three studies reported on success rates of implants placed in sites with history of one implant failure. 20,27,25 The random effects model revealed a weighted success rate of 85.0% for NR= not reported; PCS = prospective case series; RCC= retrospective cohort study. Reported data limited to early failures only; +Data limited to failed implants that were replaced by another implant; ♦ Data limited to failed implants that were replaced twice by implants.…”

“…Success criteria, however, was not disclosed in one study, 25 and the other two studies adopted distinct success classifications: Wang et al 20 considered success as absence of pain, mobility, history of exudates, and bone loss around implants not exceeding 2 mm; while Quaranta et al 27 used the criteria proposed by Albrektsson et al 31 Studies reporting exclusively on implants placed in sites with history of one early implant failure revealed a weighted implants survival rate of 91.8% (95%CI: 85.1-95.6; I 2 = 48,80%, p = 0,14) ( Figure 2C). 20,27,26 Implant success rate in these studies varied from 71 to 93.75% (Table 2). 20,27 None of the studies reported the outcomes of implants placed exclusively in sites with history of late implant failure.…”

“…20,27,26 Implant success rate in these studies varied from 71 to 93.75% (Table 2). 20,27 None of the studies reported the outcomes of implants placed exclusively in sites with history of late implant failure.…”

“…Nonetheless, implant replacement still represents a challenging scenario. 18 Although a number of retrospective cohort studies 18,19,20,21,10,22,23,24,25,26 and one prospective clinical trial 27 have evaluated survival rates of implants placed at sites with history of implant failure, these studies included limited numbers of patients. As such, the precise prognosis of implants placed at failed sites remains unclear.…”