International Journal of Oral Implantology, 01/2018

Purpose: To compare the clinical outcome of immediately loaded cross-arch maxillary prostheses supported by zygomatic implants vs conventional implants placed in augmented bone. Materials and methods: A total of 71 edentulous patients with severely atrophic maxillas, who did not have sufficient bone volume to place dental implants or when it was possible to place only two implants in the front area (minimal diameter 3.5 mm and length of 8 mm) and less than 4.0 mm of bone height subantrally, were randomised according to a parallel group design. They (35 patients) received zygomatic implants to be loaded immediately vs grafting with a xenograft, followed, after 6 months of graft consolidation, by the placement of six to eight conventional dental implants, submerged for 4 months (36 patients). To be loaded immediately, zygomatic implants had to be inserted with an insertion torque superior to 40 Ncm. Screw-retained, metal-reinforced, acrylic provisional prostheses were provided to be replaced by definitive Procera Implant Bridge Titanium prostheses (Nobel Biocare, Göteborg, Sweden) with ceramic or acrylic veneer materials 4 months after initial loading. Outcome measures were: prosthesis, implant and augmentation failures, any complications, quality of life (OHIP-14), the number of days that patients experienced total or partial impaired activity, time to function, and number of dental visits, assessed by independent assessors. Patients were followed up to 4 months after loading. Results: No augmentation procedure failed. Three patients dropped out from the augmentation group. Six prostheses could not be delivered or failed in the augmentation group vs one prosthesis in the zygomatic group, the difference being statistically significant (difference in proportions = 15.32%; P = 0.04; 95% CI: 0.23 to 31.7). Eight patients lost 35 implants in the augmentation group vs three implants in one patient from the zygomatic group, the difference being statistically significant (difference in proportions = 21.38%; P = 0.001; 95% CI: 3.53 to 39.61). In total, 14 augmented patients were affected by 20 complications vs 26 zygomatic patients (35 complications), the difference being statistically significant (difference in proportions = 31.87%; P = 0.008; 95% CI: 6.48 to 53.37). The OHIP-14 score was 3.68 ± 5.41 for augmented patients and 4.97 ± 5.79 for zygomatic patients, with no statistically significant differences between groups (mean difference = 1.29; 95%CI -1.60 to 4.18; P = 0.439). Both groups had significantly improved OHIP-14 scores from before rehabilitation (P < 0.001 for both augmented and zygomatic patients). The number of days of total infirmity was, on average, 7.42 ± 3.17 for the augmented group and 7.17 ± 1.96 for the zygomatic group, the difference not being statistically significant (mean difference = -0.25; 95% CI: -1.52 to 1.02; P = 0.692). Days of partial infirmity were on average 14.24 ± 4.64 for the augmented group and 12.17 ± 3.82 for the zygomatic group, the difference being statistically significant (mean difference = -2.07; 95% CI: -4.12 to -0.02; P = 0.048). The mean number of days to have a functional prosthesis was 444.32 ± 207.86 for augmented patients and 1.34 ± 2.27 for zygomatic patients, the difference being statistically significant (mean difference = -442.9; 95% CI: -513.10 to -372.86; P < 0.001). The average number of dental visits was 16.79 ± 10.88 for augmented patients and 12.58 ± 5.21 for zygomatic patients, the difference not being statistically significant (mean difference = -4.21; 95% CI -8.48 to 0.06; P = 0.053). Conclusions: Preliminary 4-months post-loading data suggest zygomatic implants were associated with statistically significantly less prosthetic (one vs six patients) and implant failures (one patient lost three implants versus 35 implants in eight patients) as well as time needed to functional loading (1.3 days vs 444.3 days) when compared with augmentation procedures and conventionally loaded dental implants. Even if more complications were reported for zygomatic implants, which were solved spontaneously or could be handled, zygomatic implants proved to be a better rehabilitation modality for severely atrophic maxillae. Long-term data are essential to confirm or dispute these preliminary results. Keywords: atrophic maxilla, bone augmentation, bone substitute, immediate loading, zygomatic implants Conflict of interest statement: This study was originally supported by Nobel Biocare, the manufacturer of the implants, and the provisional and definitive prosthetic components used in this study, which were provided free for the patients. However, before any results were known, Nobel Biocare withdrew the financial support and recruitment had to be stopped. Tecnoss (Giaveno, Torino, Italy) kindly donated the bone substitutes and the membranes, whereas Global D (Brignais, France) donated the osteosynthesis screws. Data property belonged to the authors and by no means did the manufacturers interfere with the publication of the results.

Purpose: To evaluate whether 4.0 mm short dental implants could be an alternative to augmentation with xenographs in the maxilla and placement of at least 10.0 mm long implants in posterior atrophic jaws. Materials and methods: A group of 40 patients with atrophic posterior (premolar and molar areas) mandibles with 5.0 mm to 6.0 mm bone height above the mandibular canal and 40 patients with atrophic maxillas having 4.0 mm to 5.0 mm below the maxillary sinus, were randomised according to a parallel group design to receive between one and three 4.0 mm long implants or one to three implants of at least 10.0 mm long in augmented bone, at two centres. All implants had a diameter of 4.0 mm or 4.5 mm. Mandibles were vertically augmented with inter-positional equine bone blocks and resorbable barriers. Implants were placed 4 months after the inter-positional grafting. Maxillary sinuses were augmented with particulated porcine bone via a lateral window covered with resorbable barriers, and implants were placed simultaneously. Implants were not submerged and were loaded after 4 months with provisional screw-retained reinforced acrylic restorations replaced after another 4 months by definitive screw-retained metal-composite prostheses. Patients were followed up to 1 year post-loading. Outcome measures were: prosthesis and implant failures, any complication, and peri-implant marginal bone level changes. Results: Three patients dropped out; one from the maxillary augmented group, one from the mandibular augmented group, and one from the maxillary short implant group. In six augmented mandibles (30%) it was not possible to place implants of at least 10.0 mm, so shorter implants were placed instead. In mandibles, one implant from the augmented group failed vs two 4.0 mm implants in two patients from the short implant group. In maxillae, three short implants failed in two patients vs seven long implants in four patients (two long implants and one short implant dropped into the maxillary sinus). Two prostheses on short implants (one mandibular and one maxillary) were placed at a later stage because of implant failures, vs six prostheses (one mandibular and five maxillary) at augmented sites (one mandibular prosthesis not delivered, three maxillary prostheses delivered with delays, one not delivered, and one failed) at augmented sites. In particular, three patients in the augmented group (one mandible and two maxillae) were not wearing a prosthesis. There were no statistically significant differences in implant failures (P (chi-square test) = 0.693; difference in proportion = 0.03; CI 95% -0.11 to 0.17) or prostheses failures (P (chi-square test) = 0.126; difference in proportion = 0.10; CI 95% -0.03 to 0.24). At mandibular sites, nine augmented patients were affected by complications vs two patients treated with short implants (P (chi-square test) = 0.01; difference in proportion = 0.37; CI 95% 0.11 to 0.63), the difference being statistically significant. No significant differences were found for maxillae: nine sinus-lifted patients vs four short implant patients were affected by complications (P (chi-square test) = 0.091; difference in proportion = 0.25; CI 95% -0.03 to 0.53). At 1-year post-loading, average peri-implant bone loss was 0.51 mm at 4 mm long mandibular implants, 0.77 mm at 10 mm or longer mandibular implants, 0.63 mm at short maxillary implants and 0.72 mm at long maxillary implants. The difference was statistically significant in mandibles (mean difference -0.26 mm, 95% CI -0.39 to -0.13, P (ANCOVA) < 0.001), but not in maxillae (mean difference -0.09 mm, 95% CI -0.24 to 0.05, P (ANCOVA) = 0.196). Conclusions: One year after loading 4.0 mm long implants achieved similar results, if not better, than longer implants in augmented jaws, but were affected by fewer complications. Short implants might be a preferable choice over bone augmentation, especially in mandibles, since the treatment is less invasive, faster, cheaper, and associated with less morbidity. However, 5 to 10 years post-loading data are necessary before making reliable recommendations. Keywords: bone substitute, inlay graft, short dental implants, sinus lift, vertical augmentation Conflict-of-interest statement: GlobalD (Brignais, France) partially supported this trial and donated the implants and prosthetic components. However, data properties belonged to the authors and by no means did GlobalD interfere with the conduct of the trial or the publication of the results.

Purpose: To evaluate whether 5.0 × 5.0 mm dental implants with a novel nanostructured calcium-incorporated titanium surface could be an alternative to implants of at least 10.0 mm long placed in bone augmented with bone substitutes in posterior atrophic jaws. Materials and methods: Forty patients with atrophic posterior (premolar and molar areas) mandibles with 5.0 mm to 7.0 mm bone height above the mandibular canal, and 40 patients with atrophic maxillas with 4.0 mm to 6.0 mm below the maxillary sinus, were randomised according to a parallel group design to receive between one and three 5.0 mm implants or one to three at least 10.0 mm-long implants in augmented bone at two centres. All implants had a diameter of 5.0 mm. Mandibles were vertically augmented with interpositional bovine bone blocks covered with resorbable barriers. Implants were placed after 4 months. Maxillary sinuses were augmented with particulated porcine bone via a lateral window covered with resorbable barriers, and implants were placed simultaneously. All implants were submerged and loaded after 4 months with provisional prostheses. Four months later, definitive screw-retained or provisionally cement metal-ceramic or zirconia prostheses were delivered. Patients were followed to 3 years post-loading and the outcome measures were: prosthesis and implant failures, any complication, and peri-implant marginal bone level changes. Results: Seven patients dropped out before the 3-year evaluation (two short mandibles, one short maxilla, two augmented mandibles and two augmented maxillae). In mandibles, two grafted patients were not prosthetically rehabilitated because of multiple complications and two implants failed in the same patient (the second was a replacement implant) vs one patient who lost a short implant and crown 2 years after loading. In maxillas one short implant failed with its provisional crown 3 months post-loading. There were no statistically significant differences in prostheses (difference in proportion = 0.001; 95% CI: -0.12 to 0.13; P = 1.000) and implant failures (difference in proportion = 0.00; 95% CI: -0.13 to 0.13; P = 1.000) up to 3 years after loading. Significantly, more complications occurred at mandibular grafted sites: 17 augmented patients were affected by complications vs eight patients treated with short implants in mandibles (difference in proportion = 0.43; 95% CI: 0.13 to 0.64; P = 0.008). In the maxilla, six sinus-lifted patients vs two patients treated with short implants were affected by complications; the difference not being statistically significant (difference in proportion = 0.21; 95% CI: -0.05 to 0.45; P = 0.232). Patients with mandibular short implants lost on average 1.10 mm of peri-implant bone at 3 years and patients with 10.0 mm or longer mandibular implants lost 1.39 mm. Patients with maxillary short implants lost on average 1.04 mm of peri-implant bone at 3 years and patients with 10 mm or longer maxillary implants lost 1.43 mm. Longer implants showed a greater bone loss up to 3 years after loading than short implants both in maxillae (mean difference: -0.39 mm; 95% CI: -0.70 to -0.07 mm; P = 0.017) and in mandibles (mean difference: -0.29 mm; 95% CI: -0.53 to -0.05 mm; P = 0.020). Conclusions: Three years after loading, 5.0 mm × 5.0 mm implants achieved similar results than longer implants placed in augmented bone. Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster, cheaper and associated with less morbidity. However, 5- to 10-year post-loading data are necessary before making reliable recommendations. Keywords: bone substitutes, inlay graft, short dental implants, sinus lift, vertical augmentation Conflict-of-interest statement: MegaGen (Implant, Gyeongbuk, South Korea) partially supported this trial and donated implants and prosthetic components used in this study, whereas Tecnoss (Giaveno, Italy) donated the bone substitutes and the barriers. Data property belonged to the authors and by no means did the manufacturers interfere with the conduct of the trial or the publication of its results.

Purpose: To compare the clinical outcome of single, partial and complete fixed implant supported prostheses immediately loaded (within 48 h), early loaded at 6 weeks, and conventionally loaded at 3 months (delayed loading). Materials and methods: A total of 54 patients (18 requiring single implants, 18 partial fixed prostheses, and 18 total fixed cross-arch prostheses) were randomised in equal numbers at two private practices to immediate loading (18 patients), early loading (18 patients), and conventional loading (18 patients) according to a parallel group design with three arms. To be immediately or early loaded, implants had to be inserted with a torque superior to 40 Ncm. Implants were initially loaded with provisional prostheses, replaced after 4 months by definitive ones. Outcome measures were prosthesis and implant failures, complications and peri-implant marginal bone levels. Results: Two conventionally loaded patients rehabilitated with cross-arch fixed total prostheses dropped-out up to 1 year post-loading. No implant or prosthesis failed and three complications occurred, one in each loading group. Peri-implant marginal bone loss was 0.19 ± 0.44 mm at immediately loaded implants, 0.18 ± 0.66 mm at early loaded implants and 0.25 ± 0.28 mm at conventional loaded implants. There were no statistically significant differences in complications (P = 1.000) and bone loss (P = 0.806) between the three loading strategies. Conclusions: All loading strategies were highly successful and no differences could be observed for implant survival and complications when loading implants immediately, early or conventionally. Keywords: Calcium-incorporated titanium, early loading, randomised controlled trial, RBM surface, surface modification Conflict of interest statement: This trial was partially funded by MegaGen, the manufacturer of the implants evaluated in this investigation, however data belonged to the authors and by no means did the manufacturer interfere with the conduct of the trial or the publication of its results.

Purpose: To evaluate whether there are aesthetic and clinical benefits to using a newly designed abutment (Curvomax), over a conventional control abutment (GingiHue). Materials and methods: A total of 49 patients, who required at least two implants, had two sites randomised according to a split-mouth design to receive one abutment of each type at seven different centres. The time of loading (immediate, early or delayed) and of prosthesis (provisional crowns of fixed prosthesis) was decided by the clinicians, but they had to restore both implants in a similar way. Provisional prostheses were replaced by definitive ones 3 months after initial loading, when the follow-up for the initial part of this study was completed. Outcome measures were: prosthesis failures, implant failures, complications, pink esthetic score (PES), peri-implant marginal bone level changes, and patient preference. Results: In total, 49 Curvomax and 49 GingiHue abutments were delivered. Two patients dropped out. No implant failure, prosthesis failure or complication was reported. There were no differences at 3 months post-loading for PES (difference = -0.15, 95% CI -0.55 to 0.25; P (paired t test) = 0.443) and marginal bone level changes (difference = -0.02 mm, 95% CI -0.20 to 0.16; P (paired t test) = 0.817). The majority of the patients (30) had no preference regarding the two abutment designs; 11 patients preferred the Curvomax, while five patients preferred the GingiHue abutments (P (McNemar test) = 0.210). Conclusions: The preliminary results of the comparison between two different abutment designs did not disclose any statistically significant differences between the evaluated abutments. However the large number of missing radiographs and clinical pictures casts doubt on the reliability of the results. Longer follow-ups of wider patient populations are needed to better understand whether there is an effective advantage with one of the two abutment designs. Keywords: abutment design, aesthetics, dental implants Conflict of interest statement: This research project was originally partially funded by Biomax (Andover, MA, USA), the manufacturer of the Curvomax abutments evaluated in this investigation. Biomax, under pressure from some investigators, asked to modify the original agreed protocol. In a following phase, Zimmer-Biomet (Palm Beach Gardens, Florida, USA), the manufacturer of the implants and the GingiHue abutments, took over the funding of this project. Data belonged to the authors and the sponsors did not interfere with the publication of results.

Purpose: To present the medium-term results of one-stage guided bone regeneration (GBR) using autologous bone and anorganic bovine bone, placed in layers, in association with resorbable collagen membranes, for the reconstruction of horizontal bony defects. Materials and methods: This study was designed as an uncontrolled prospective study. Partially edentulous patients, having less than 6.0 mm and more than 4.0 mm of residual horizontal bone width were selected and consecutively treated with simultaneously implant installation and bone regeneration by using 2.0 mm of autologous bone and 2.0 mm of anorganic bovine bone that was placed in layers and then covered with a resorbable collagen membrane. Outcome measures were: implant and prosthesis failures, any complications, peri-implant marginal bone level changes, probing pocket depth (PPD) and bleeding on probing (BOP). Results: In total, 45 consecutive patients (20 male, 25 female) with a mean age of 52.1 years each received at least one GBR procedure, with contemporary placement of 63 implants. At the 3-year follow-up examination, no patient had dropped out and no deviation from the original protocol had occurred. No implant or prosthesis failed. In six patients (13.3%) the collagen membrane was slightly exposed 1 to 2 weeks after bone reconstruction. Four of these patients were moderate smokers. Post-hoc analysis using Fisher's exact test found significant association (P = 0.0139) between a smoking habit and early membrane exposure. Mean marginal bone loss experienced between initial loading and 30 months afterwards was 0.60 ± 0.20 mm (95% CI 0.54 - 0.66). The mean BOP values measured at the definitive restoration delivery were 1.23 ± 0.93, while 2 years later they were 1.17 ± 0.78. The difference was not statistically significant (-0.06 ± 0.76; P = 0.569). The mean PPD values measured at the definitive restoration delivery were 2.62 ± 0.59 mm, while 2 years later they were 2.60 ± 0.54 mm. The difference was not statistically significant (-0.03 ± 0.62; P = 0.765). Conclusions: Within the limitations of the present study, the use of a 2.0 mm layer of particulated autologous bone on the implant threads, and a 2.0 mm layer of anorganic bovine to cover the resorbed ridge, in combination with the resorbable collagen membrane, seems to be a viable treatment option for the reconstruction of horizontal bony defects. Keywords: autogenous bone, bone substitute, dental implants, guided bone regeneration Conflict of interest statement: This study was not supported by any company, and there are no conflicts of interest.

Purpose: To identify 100 top-cited articles published in periodontal journals and analyse the research trends by using citation analysis. Materials and methods: 100 top-cited articles published in periodontal journals were retrieved by searching the database of the ISI Web of Science and Journal Citation reports. For each article, the following principal bibliometric parameters: authorship, geographic and institute origin, manuscript type, study design, scope of study, and citation count of each time period were analysed from 1965 to 2015. Results: The identified 100 top-cited articles were retrieved from five periodontal journals and citation counts were recorded between 262 and 1,693 times. For the institute of origin, the most productive institute, in terms of the number of 100 top-cited articles published, was the University of Gothenburg (Sweden) (n = 19), followed by the Forsyth Dental Center (USA) (n = 15). Most manuscripts were original research (n = 74), and the inflammatory periodontal disease (n = 59) was the most frequent topic studied. Interestingly, the trend of increase average citation reached significance for implantology (β = 26.75, P = 0.003) and systemic interactions (β = 29.83, P = 0.005), but not for inflammatory disease (β = -10.30, P = 0.248) and tissue regeneration (β = 9.04, P = 0.081). By using multivariable linear regression in a generalised linear model, suitable published journal (Journal of Clinical Periodontology), geographic regions (Europe), more intense international collaboration, adequate manuscript type (review article) and study design (systematic review) could be attributed to escalating average citation counts in implantology (all P < 0.05). However, for systemic interactions, only geographic region and study design were significantly associated with the increasing citation trend. Conclusions: These principal bibliometric characteristics revealed escalated trends in average citation count in implantology throughout time. Keywords: bibliometrics, citation analysis, implantology, periodontology Conflict-of-interest statement The authors have stated explicitly that there are no conflicts of interest in connection with this article. The study was self-funded by the authors and their institution.

Purpose: To describe a rare case of odontogenic brain abscess. Materials and methods: A healthy, 35-year-old male had two dental implants placed in a simultaneously augmented maxillary sinus. One implant failed and the patient developed a maxillary sinusitis that failed to improve following antibiotic treatment at home. The neglected sinus infection led to formation of a brain abscess. The patient was hospitalised only when he had pan sinusitis with neurological signs. Symptoms were headache attacks, a subfebrile fever and a purulent secretion from the left nostril. The osteomeatal complex was blocked, the maxillary sinus was filled with pus and the Schneiderian membrane thickened. The patient was treated with intravenous antibiotic treatment. Computerised tomography (CT) and magnetic resonance imaging (MRI) scans and functional endoscopic sinus surgery (FESS), were implemented. When his conditions worsened, the patient underwent a left frontal mini craniotomy. Results: Following the craniotomy and antibiotic treatment, there was a gradual resolution and the patient was dismissed after 2 months in hospital with no neurological deficit or signs of sinusitis. Conclusions: Maxillary sinusitis following dental implant insertion and concomitant maxillary sinus elevation should be treated immediately and thoroughly since untreated sinusitis may cause life-threatening situations such as a brain abscess. In case of severe infection, clinicians should refer immediately the patient to hospital specialists. Keywords: brain abscess, dental implant, maxillary sinus augmentation Conflict-of-interest statement: The authors have stated explicitly that there are no conflicts of interest. The manuscript was self-funded.

This section presents a brief review of articles on dental implants considered of special interest for the reader, in order to encourage the development of research, the interest for data analysis and the attention to scientific publications. Your comments are welcome. Please contact Dr Michele Nieri at michelenieri@gmail.com.