International Journal of Oral Implantology, 02/2014

Purpose: To compare the effectiveness of two different techniques to lift the maxillary sinus via a crestal approach: the Summers versus the Cosci technique. Materials and methods: Fifteen partially edentulous patients missing bilaterally maxillary molars and/ or premolars, having 4 to 7 mm of residual crestal height and at least 5 mm thickness below the maxillary sinuses measured on CT scans, were randomised to have implants placed in sinuses crestally lifted according to the Cosci or the Summers techniques, with bone substitutes according to a split-mouth design. Implants were left to heal submerged for 6 months. Implants were loaded with acrylic provisional crowns/prostheses. Screw-retained definitive metal-ceramic prostheses were delivered 4 months after provisional loading. Outcome measures were: prosthesis and implant failures; any complications; operation time; operator preference; patient preference and peri-implant marginal bone level changes assessed by a blinded outcome assessor. All patients were followed to 3 years after implant loading. Results: Nineteen study implants were placed according to each technique. Three years after loading, 3 patients dropped out and no implant failed. No discomfort/complications occurred at sites treated with the Cosci technique, whereas 12 patients reported discomfort during the augmentation procedure at the side treated with the Summers technique; this was statistically significant (P = 0.0005). In one of these patients, a perforation of the sinus membrane occurred. Postoperatively, headache was reported by 9 patients and swelling occurred in 3 of these patients at the Summers treated sides. Statistically significant less time (9.7 mins, SD = 4.0, P < 0.001, 95% CI -11.9 to -7.5) was required to place implants according to the Cosci technique (33 versus 24 mins on average). The 2 operators and 14 out of 15 patients preferred the Cosci technique 1 month after surgery (P = 0.001), and 1 year after surgery (13 out of 15 patients, P = 0.007). The ceramic layer of one prosthesis of the Summers' group and one abutment screw of the Cosci's group loosened between 1 to 3 years post-loading. After 3 years, implants inserted according to the Cosci technique lost 1.39 mm of peri-implant bone versus 1.54 mm for the implants placed with the Summers technique. There were no statistically significant differences for marginal bone level changes between the two groups (difference 0.15 mm, 95% CI -0.11 to 0.41, P = 0.24). Conclusions: Both crestal sinus lift techniques produced successful results over a 3-year follow-up period, but the Cosci technique required less surgical time, determined less intra- and postoperative morbidity and was preferred by patients. Keywords: bone augmentation, crestal sinus lift, patient morbidity, patient preference, surgical techniques Conflict of interest statement: This was an investigator-initiated trial, however the trial was partially supported by Zimmer Dental Italy, Vittorio Veneto (TV), Italy. One of the authors (Dr Cosci), who treated 8 patients in this study, is the inventor of the Cosci technique and his partipation was a prerequisite of the sponsor to support the trial.

Purpose: To compare immediately loaded post-extractive single implants using a definitive abutment versus provisional abutment later replaced by custom-made abutment. Materials and methods: In two private clinics, 28 patients in need of one single post-extractive implant in the maxilla or mandible from the left second premolar to the right second premolar area were randomised shortly before tooth extraction to provisional abutment (PA) and definitive abutment (DA) groups. Three patients had to be excluded for buccal wall fracture after tooth extraction. In the PA group, implants were immediately restored using a platform-switched provisional titanium abutment and definitive platform-switched titanium abutments were used in the DA group. In both groups, a non-occluding provisional single crown was provided. Implants were definitively restored after 4 months. In the PA group, the abutment was removed and the impression was made directly on the implant platform. In the DA group an impression of the abutment was made using a retraction cord. Outcome measures were: implant failures; complications; and marginal peri-implant bone level changes. Patients were followed up to 1 year after loading. Results: Twelve patients were randomised to the DA group and 13 patients to the PA group. At the 12-month follow-up, no implant failed. One biological complication occurred in the DA group and one mechanical complication occurred in the PA group. All complications were successfully treated. One year after loading, implants in the DA group lost an average of 0.11 mm (SD: 0.06) of periimplant bone and implants in PA group about 0.58 mm (SD: 0.11). At the 12-month follow-up, there was a statistically significant difference in bone level change between groups (mean difference: 0.48 mm, CI 95% 0.40; 0.55, P < 0.0001). Conclusions: Within the limits of this study, the non-removal of abutments placed at the time of surgery resulted in the maintenance of 0.5 mm more bone levels around immediately restored postextractive single implants than repeated abutment removal, although this amount of bone maintenance may not have a clinical impact. Keywords: abutment dis/reconnection, bone loss, implant-abutment interface, platform switching, post-extractive implants Conflicts of interest notification: Dr Tommaso Grandi and Dr Paolo Guazzi serve as consultants for JDentalCare. This study was completely self-financed and no funding was sought or obtained, not even in the form of free materials.

Objectives: To compare the effectiveness of onlay bone blocks of equine origin (test or XB group) with autogenous bone blocks (control or AB group) harvested from the ramus or the iliac crest for the rehabilitation of partially or fully edentulous atrophic jaws with implant supported prostheses. Materials and methods: Forty patients with partially or fully edentulous atrophic jaws having less than 5 mm of residual crestal bone height and/or less than 3 mm of bone thickness, as measured on computerised tomography (CT) scans, were randomised into two groups according to a parallel group design, either to be augmented with autogenous onlay bone blocks (20 patients; AB group) from the mandibular ramus or the iliac crest, or with onlays blocks of spongious bone of equine origin (20 patients; XB group). Two centres treated 20 patients each. Six XB blocks were modelled on lithographic models of the jaws before grafting. The blocks were fixed with screws and osteosynthesis plates and were covered with resorbable barriers made of equine cortical bone and fixed with tacks. The autogenous bone grafts were left to heal for 4 months and the xenografts for 7 months before placing implants, which were submerged. After 4 months, either bar-retained overdentures or provisional reinforced acrylic prostheses were delivered. Provisional prostheses were replaced, after 4 months, by definitive fixed prostheses. Outcome measures were: prosthesis and implant failures; complications; patient satisfaction; pain recorded 3 and 10 days post-augmentation; number of days of hospitalisation, total and partial infirmity days. All patients were followed for 4 months after loading. Results: All patients could be rehabilitated with implant-supported prostheses and none dropped out. Twenty-eight patients were augmented in the maxilla (15 with AB and 13 with XB) and 12 in the mandible (5 with AB and 7 with XB). No AB graft failed totally versus 10 XB grafts (difference = 0.5; 95% CI 0.23 to 0.68; P = 0.0004). In particular, all 7 XB mandibular grafts and 5 out of 6 XB blocks (3 in mandibles and 2 in maxillas), which were previously modelled on lithographic models of the jaws failed. One implant failed in one AB patient versus 11 implants in 4 XB patients (P = 0.3416). All but 1 prostheses were loaded in time in the AB patients, versus 4 prostheses which were loaded with delays in XB patients because of graft and implant failures (P = 0.3416). Four complications occurred in 4 AB patients versus 15 complications in 12 XB patients (difference = 0.4; 95% CI 0.09 to 0.63; P = 0.0225). Fourteen AB patients reported moderate pain 3 days postoperatively versus 6 XB patients (P = 0.0562); at 10 days, 10 AB patients reported moderate pain versus 1 XB patient (difference = -0.45; 95% CI -0.65 to -0.17; P = 0.0033). The 14 patients harvested from the iliac crest were hospitalised for an average of 3.1 nights, whereas 7 patients treated with XB were hospitalised on average for 1.4 nights (P 0.0001). The number of total and partial infirmity days was 126 for theAB group and 43 for the XB group, and 220 for the AB group and 93 for the XB group, respectively (mean day difference = -4.15; 95% CI -7.35 to -0.95; P = 0.0134 and mean day difference = -5.7; 95% CI -10.01 to -1.39; P = 0.0116, respectively). Seventeen AB patients versus 19 XB patients were fully satisfied with function of their prostheses (P = 0.6050), 18 AB patients versus 12 XB patients were fully satisfied with aesthetics of their prostheses (P = 0.0648), and 5 and 3 patients, respectively would not undergo the same procedure again (P = 0.6948). There were no differences between the outcomes of the two centres with exception of prosthesis failures and complications in the maxilla. Conclusions: Autogenous onlay bone blocks are superior to equine onlay bone blocks, especially in mandibles, where all equine blocks failed, therefore we strongly discourage the use of onlay bone blocks of equine origin in mandibles. Keywords: atrophic jaw, autogenous bone, bone substitutes, blocks, iliac crest Conflict of interest statement: Bioteck, Arcugnano (VI), Italy, partially supported this trial, however data belonged to the authors.

Objectives: To evaluate the outcome of immediately loaded distally cantilevered mandibular full-arch prostheses according to the 'all-on-four' concept supported by implants placed in both fresh extraction and healed sites. Material and methods: A prospective study was conducted in 24 patients with extraction of all remaining mandibular teeth and placement of 4 implants per patient (2 mesial axial and 2 distal tilted) for full-arch mandibular restorations. Implants were inserted in fresh extraction sockets 2.3 ± 1.0 per patient and 1.7 ± 1.0 implants in healed sites. Implants placed in fresh extraction sites (n = 55) were significantly (P 0.01) more deeply inserted than implants (n = 41) placed in healed sites (peri-implant alveolar crest: +1.6 ± 0.8 mm vs +0.6 ± 0.7 mm). Patients received an immediate provisional fixed dental prosthesis and, 3 months later, a definite resin veneered prosthesis with metal framework. At the 12-and 24-month follow-up, patients were evaluated for implants and prosthesis success, for prosthodontic maintenance efforts and patient satisfaction. At both follow-up examinations, peri-implant marginal bone level, implant pocket depth, plaque, bleeding, gingival and calculus indices were evaluated and compared between implants placed in fresh extraction and healed sites. Results: At the 24-month follow-up, no implant failed and all prostheses were stable. There were five fractures of the provisional prosthesis in 5 patients but no fracture of the definite prostheses. For the definite prostheses, 15 acrylic teeth had to be renewed/repaired (in 10 patients) and 18 patients presented the need for the implant-supported prosthesis to be rebased. Peri-implant marginal bone level after 12 and 24 months was -0.18 ± 0.20 mm and -0.40 ± 0.29 mm for all implants (P 0.001) representing bone level differences of 0.35 mm between implants placed in healed and post-extractive sites at both the 1st year (95%-CI:-0.49 to -0.20) and the 2nd year (95%-CI: -0.57 to -0.14) assessment. Plaque (1st year: 1.17 ± 0.48 versus 0.5 ± 0.6; P 0.001; 2nd year: 1.21 ± 0.51 versus 0.55 ± 0.6; P 0.001) and calculus indices (1st year: 0.92 ± 0.28 versus 0.45 ± 0.51; P 0.001; 2nd year: 1.00 ± 0.42 versus 0.5 ± 0.51; P 0.001) were significantly higher for implants placed in fresh extraction than in healed sites. Patients' subjective satisfaction score rating assessed by 5 items was high at the 1- (score: 4.6 ± 0.4) and 2-year evaluation (score: 4.7 ± 0.36). Conclusion: Within the limits of this study, immediately loaded full-arch prostheses can be supported by four implants placed simultaneously into healed and fresh extraction sites. Keywords: edentulous mandible, extraction sites, fixed full arch prostheses, immediate implant placement, immediate loading Conflict of interest statement: Prof Gerald Krennmair was supported by a grant from Camlog Foundation to conduct this research.

Purpose: The aim of this prospective multicentre study was to evaluate the clinical outcome of immediately loaded single implants. Materials and methods: Patients were recruited at six clinical centres. Inclusion criteria were singletooth replacement in fully healed sites or post-extraction sockets with adequate bone height and width, to place an implant of at least 3.5 mm in diameter and 10.0 mm in length. All implants (AnyRidge, MegaGen, Gyeongbuk, South Korea) were functionally loaded immediately after placement. After 3 months, final crowns were delivered. All implants were followed for 1 year. Outcome measures were: implant stability; complications; peri-implant marginal bone level changes; probing pocket depth. Results: Fifty-seven implants (38 in the maxilla and 19 in the mandible) were placed in 46 patients (23 males, 23 females, aged between 18 to 73 years). Ten implants were placed in post-extraction sockets. Two patients (two implants) withdrew from the study and were classified as drop-outs. At the end of the study, only one implant was lost in a healed site. All the surviving implants were stable, giving an overall 1-year survival rate of 97.7% (patient-based). A few complications (one patient experienced swelling after surgery, two had loosened abutments and another patient had a ceramic crown fracture) were encountered. After 1 year of functional loading, the patients had lost an average of 0.32 mm (± 0.22) of peri-implant marginal bone; the mean probing pocket depth (PPD) was 2.16 mm (± 0.68). Conclusions: Within its limit (limited number of patients treated and self-evaluation of the outcomes), this study supports the concept that immediate functional loading of single dental implants can be a successful treatment procedure, with satisfactory clinical outcomes. Keywords: dental implants, immediate loading, single implant Conflict-of-interest statement: MegaGen Implant Co., Gyeongbuk, South Korea, the manufacturer of the implants used in this investigation, partially supported this study by donating the implants and prosthetic components; however, the research data belonged to the authors and by no means did Megagen interfere with the conduct of the study or the publication of the results.