International Journal of Oral Implantology, 03/2018

Purpose: To summarise systematic reviews that assess the effects of different interventions for implant prosthetic rehabilitation in partially edentulous patients with the presence of bone atrophy. Materials and methods: Only systematic reviews of randomised controlled trials (RCTs) dealing with partially edentulous adult patients presenting bone defects were included. Treatments of interest were bone augmentation procedures, use of short, tilted or zygomatic implants, sinus lift and transposition of the inferior alveolar nerve. Outcome variables considered were: prosthetic and implant failure, complications, radiological and clinical peri-implant bone level variation, aesthetic and functional satisfaction, and vestibular peri-implant soft tissue recession. A search of systematic reviews of RCTs selected from MEDLINE, the Cochrane Database of Systematic Review, and the Prospero register published in the past 5 years (May 2012 - May 2017) was performed. Systematic reviews were also manually searched. Independent data extraction by two authors using predefined data fields, including ROBIS risk of bias, was executed. Results: A total of 12 systematic reviews of RCTs were identified for inclusion in the overview. Eight reviews were considered at low risk of bias. Short implants (≤ 8 mm) were associated with a notable decrease in complications compared to long implants with bone augmentation procedures. Many trials compared different sinus lift procedures and different bone augmentation techniques. None of these indicated that one procedure could reduce prosthetic or implant failures when compared to the other. The use of a membrane can contribute to the regeneration of the hard tissue in horizontal augmentation. Different membranes or bone substitutes did not give substantially different results. No data are available regarding comparisons involving zygomatic implants or tilted implants or transposition of the alveolar nerve. Conclusions: Overall, the evidence is not sufficiently robust to determine the best treatment for implant prosthetic rehabilitation in partially edentulous patients presenting bone atrophy. In terms of vertical defects, if the short implants can be used they should be used because the number of complications are reduced compared to longer implants with sinus lift or bone augmentation. Nevertheless, caution should be exercised because long-term follow-up studies were not available. No conclusions can be drawn regarding the comparison between different vertical bone augmentation techniques in atrophic posterior mandible because quantitative meta-analyses were not performed. With regards to horizontal defects, the use of a membrane appears to increase the regeneration of the hard tissue but no differences were detected in prosthesis or implant failures or in complications. Keywords: bone regeneration, dental implants, overview of systematic review, umbrella review

Purpose: The aim of this study was to compare survival and success rates of 6 mm-long and 10 mm-long implants in partially edentulous posterior areas. Materials and methods: Twenty-four patients with a partially edentulous area were included in the study. Patients were randomly allocated according to a parallel group design to receive 6 mm or 10 mm-long implants. A total of 54 implants were placed (26 × 6 mm implants). Patients were followed for 10 years after prosthetic loading. Outcome measures were prosthesis and implant survival, marginal bone level changes and complications. Results: After 10 years, 17 patients (eight with 6 mm implants and nine with 10 mm implants) were available: three 6 mm and four 10 mm patients were lost to follow-up. One 6 mm implant failed during the healing period and its related prosthesis could not be placed. No implants were lost after loading. Nine patients in the 6 mm group registered a total of 15 complications: two mucositis, six decementations and seven chippings. Ten patients in the 10 mm group registered a total of 13 complications: five mucositis, two decementations and six chippings. Overall the difference for complications between the two groups was not statistically significant (P = 0.22; difference in proportion = -0.02; 95% CI: -0.31 to 0.27). Decementations in the 6 mm group were statistically significant higher than the 10 mm group (P = 0.04; difference in proportion = 0.39; 95% CI: 0.03 to 0.74). Marginal bone loss at 10 years was 0.84 and 0.37 mm with the 6 mm and 10 mm groups, respectively (difference between the two groups 0.49 mm; 95% CI -0.31; 1.29; not statistically significant: t test P = 0.22). Conclusions: Rehabilitations supported by 6 mm or 10 mm-long implants showed similar clinical outcomes in terms of survival and success rates, although 6 mm implants had more decementations. Keywords: complications, partial edentulism, posterior edentulous jaw, randomised control trial, short dental implant Conflict of interest statement: The present study was supported by grant 369_2004 from ITI, Basel, Switzerland used to provide free implants and prosthetic components to the patient. The authors declare no conflict of interest.

Purpose: To compare the outcome of cross-arch prostheses supported either by 5 mm long or 11.5 mm long implants placed flapless and immediately restored with a metal-resin screw-retained cross-arch prostheses. Materials and methods: Thirty patients with edentulous or to-be- rendered edentulous mandibles, and 30 with edentulous maxillas, having sufficient bone to allow the placement of four and six implants respectively, of at least 11.5 mm long, were randomised according to a parallel group design into two equal groups and received either 5 mm or 11.5 mm long implants at one centre. Implants had a diameter of 5 mm, were to be placed flapless, and with an insertion torque of at least 50 Ncm. Mandibles received four implants between the mental foramina. Implants were to be immediately loaded with metal-resin definitive prostheses the same day as implant placement. Patients were followed to 5 years post-loading and the outcome measures were: prosthesis and implant failures, complications, and peri-implant marginal bone level changes. Results: Four patients per group dropped out. Two prostheses were remade, one on short maxillary implants and one on long mandibular implants (difference in proportions = 0; 95% CI: -0.15 to 0.15; P = 1.000). Three patients lost six short implants vs three patients who lost four long implants (difference in proportions = 0; 95% CI: -0.19 to 0.19; P = 1.000). Four short implant patients were affected by complications vs five patients with long implants (difference in proportions = 0.04; 95% CI: -0.17 to 0.25; P = 1.000). There were no statistically significant differences for prostheses failures, implant failures and complications. Patients with mandibular short implants lost on average 0.22 mm of peri-implant bone at 5 years while patients with long mandibular implants lost 0.83 mm. Patients with maxillary short implants lost on average 0.30 mm of peri-implant bone at 5 years and patients with long maxillary implants lost 0.89 mm. Short implants showed less bone loss when compared with long implants and the differences up to 5 years were statistically significant both in maxillae (mean difference = 0.59 mm, 95% CI: 0.33 to 0.86 mm, P .0001) and in mandibles (mean difference = 0.61 mm, 95% CI: 0.36 to 0.86 mm, P 0.0001). Conclusions: Flapless-placed 5 mm long implants achieved similar results as 11.5 mm long implants when supporting immediately loaded cross-arch prostheses both in maxillae and mandibles up to 5 years after loading. These results must be confirmed by other trials, and 10 years post-loading data is necessary before making reliable recommendations. Keywords: edentulous jaw, flapless implant placement, immediate loading, short dental implants Conflict of interest statement: This study was completely self-financed and no financial support has been sought or obtained, not even in the form of free materials.

Purpose: To compare the clinical outcome of dental implants restored with definitive occluding partial fixed prostheses within 1 week after implant placement with immediate non-occluding provisional restorations to be replaced by definitive prostheses after 4 months. Materials and methods: Forty partially edentulous patients treated with one to three dental implants, at least 8.5 mm long and 4.0 mm wide, inserted with a torque of at least 35 Ncm, were randomised in two groups of 20 patients each, to be immediately loaded with partial fixed prostheses. Patients in one group received one definitive screw-retained, metal-ceramic prosthesis in occlusion within 1 week after placement. Patients in the other group received one non-occluding provisional acrylic reinforced prosthesis within 24 h of implant placement. Provisional prostheses were replaced by definitive ones after 4 months. The follow-up for all patients was 3 years post-loading. Outcome measures were prosthesis and implant failures, any complications, peri-implant marginal bone level changes, aesthetic evaluation by a dental practitioner, patient satisfaction, chair time and number of visits at the dental office from implant placement to delivery of definitive restorations. Results: Three patients dropped out, one from the non-occlusal group and two from the occlusal group. Two immediately occlusally loaded implants with their related definitive prostheses failed early (difference in proportions = 0.10; 95% CI = -0.03 to 0.23; P = 0.488). Five patients from the occlusally loaded group were affected by six complications vs three patients (three complications) in the non-occlusally loaded group. The difference in proportions was not statistically significant (difference in proportions = 0.08; 95% CI = -0.17 to 0.34; P = 0.697). Three years after loading, patients subjected to occlusal loading lost an average of 1.13 mm of peri-implant bone vs 1.03 mm of patients restored with non-occluding definitive partial fixed prostheses. There were no statistically significant differences for marginal bone level changes between the two groups (mean difference = 0.10 mm; 95% CI -0.62 to 0.82; P = 0.779). No significant were the differences for pink aesthetic scores (7.09 vs 6.90; P = 0.873); for aesthetics evaluated by patients (Mann-Whitney U test P = 0.799) and function satisfaction (Mann-Whitney U test P = 0.578). Significantly less chair time (mean difference -38.00; 95% CI -58.96 to -17.04; P = 0.001) and number of visits (mean difference -2.15; 95% CI -2.77 to -1.53; P < 0.001) were required for the immediate definitive prosthesis group. Conclusions: This study did not provide a conclusive answer, but suggests that immediate occlusal loading by manufacturing immediate definitive partial fixed prostheses decreases chair time and number of visits. Keywords: immediate loading, non-occlusal loading, partial edentulism Conflict of interest statement: Zimmer-Biomet, the manufacturer of the implants, bone substitutes and resorbable membranes used in this investigation, supported this trial, however data belonged to the authors and by no means did the sponsor interfere with the conduct of the trial or the publication of its results.

Purpose: To evaluate the outcome of three (fixed-on-3 = Fo3) vs four (fixed-on-4 = Fo4) implants immediately restored with metal-resin screw-retained cross-arch prostheses in fully edentulous jaws. Materials and methods: Forty-eight edentulous or to be rendered edentulous patients were randomised in six centres (eight patients per centre) to the Fo3 group (24 patients: 12 maxillae and 12 mandibles) and to the Fo4 group (24 patients: 12 maxillae and 12 mandibles) according to a parallel group design. To be immediately loaded, implants had to be inserted with a minimum torque of 40 Ncm. Outcome measures were prosthesis and implant failures, complications and peri-implant marginal bone level changes evaluated up to 1 year post-loading. Results: One maxillary prosthesis per group was delayed loaded because implants could not be placed with a torque of at least 40 Ncm. Ten patients in the Fo3 group and four in the Fo4 group had implants placed flapless. One year after loading no drop out occurred. One patient of the Fo3 group lost three implants vs three patients of the Fo4 group who lost four implants, the difference being no statistically significant (risk difference = -0.08; 95% CI: -0.27 to 0.10; Fisher's exact test P = 0.609). One mandibular Fo3 and one maxillary Fo4 prosthesis failed. Six Fo3 patients were affected by complications vs three Fo4 patients (risk difference = 0.12; 95% CI: -0.10 to 0.34; Fisher's exact test; P = 0.461). Both groups lost marginal bone in a statistically significant way (0.22 ± 0.20 mm for Fo3 patients and 0.40 ± 0.21 mm for Fo4 patients), with Fo3 group showing less marginal peri-implant bone loss than Fo4 group (estimate of the difference = -0.18 (standard error: 0.06) mm; 95% CI: -0.30 to -0.06; P = 0.005). There were no differences in clinical outcomes between the six operators. Conclusions: These preliminary results suggest that immediately loaded cross-arch prostheses of both jaws can be supported by only three dental implants at least up to 1 year post-loading, though longer follow-ups are definitively needed. Keywords: dental implants, full edentulism, immediate loading, randomised controlled trial Conflict of interest statement: Sweden & Martina, the manufacturer of the implants used in this investigation, supported this trial, however data belonged to the authors and by no means did the sponsor interfere with the conduct of the trial or the publication of its results.

Purpose: To compare the outcome of immediately loaded and one-stage conventionally loaded variable-thread tapered implants in the posterior maxilla. Materials and methods: This study was designed as a split-mouth randomised controlled trial. Twenty-six patients missing teeth bilaterally in the posterior maxilla received three to four implants in each of the posterior sextants. Bone quality was recorded based on Misch criteria (D1-D4) and insertion torque values were measured using a manual wrench. The implants on one side were immediately loaded with a temporary resin fixed partial denture on definitive multi-unit abutments. The implants in the contralateral side received definitive multi-unit abutments according to the one-stage unloaded protocol. Three to 3.5 months following implant placement, the implants were restored with metal-ceramic fixed prostheses. Outcome measures were implant and prosthesis failure rates, complications, and peri-implant bone level changes at 1 year following delivery of the definitive prostheses. Results: Two patients dropped out prior to the delivery of definitive prostheses. Four implants supporting a four-unit immediately loaded prosthesis failed in one patient, 3 months following delivery of the definitive prostheses. None of the conventionally loaded implants or prostheses failed. There were no significant differences in the proportions of implant and prosthesis failures (difference = 4.2%; 95% CI -4.2 to 12.6%; P = 0.999). In the immediately loaded group, four early prosthetic complications occurred during the provisionalization phase (three small resin chippings and one prosthetic screw loosening). No other complications were reported. The difference in the rate of complications between the two interventions was not statistically significant (difference = 16.7%; 95% CI -1.2% to 35.6%; P = 0.125). The 1-year peri-implant marginal bone level changes were evaluated in 23 patients (77 immediately loaded and 76 conventionally loaded implants). On average, patients lost 0.42 mm at the immediately loaded and 0.46 mm at the conventionally loaded implants, the difference being statistically not significant (difference = 0.044 mm; 95% CI -0.27 to 0.18 mm; P = 0.701). Conclusions: Immediate loading of 3- to 4-unit fixed partial prostheses supported by variable-thread implants in the posterior maxilla can yield good and similar 1-year results to one-stage conventionally loaded implants. Keywords: immediate loading, insertion torque, maxilla, randomised controlled trial, variable thread tapered implant Conflict-of-interest statement: This study was independently designed by the investigators but was supported by Nobel Biocare Services AG, Kloten, Switzerland (grant number 2010-954) in the form of free surgical kits, implants and prosthetic components. No other financial contribution was received by any of the authors or their institutions. The authors declare that there is no affiliation or any other conflict of interest to the sponsor and that Nobel Biocare did not in any way interfere with the conduct of the trial or the publication of its results.

Purpose: The present study evaluated the hypothesis that implants inserted at bone level or supracrestally have different outcomes in single tooth replacements against the alternative hypothesis of no difference. Materials and methods: This study was designed as a randomised, split-mouth, controlled pilot trial. Ten patients, each missing two bicuspids or molars, were treated with 20 implants featuring 0.75 mm of machined collar. Each patient randomly received one implant inserted at bone level (BL) and one inserted 0.75 mm to 1 mm above the alveolar crest (SC), measured with a periodontal probe during surgery. All the implants were inserted into healed healthy bone with an insertion torque ranging between 35 Ncm and 45 Ncm. Both implants were loaded with screw-retained acrylic-resin temporary crowns 3 months after implant insertion and 3 months later with screw-retained zirconia-ceramic definitive crowns. Outcome measures were implant/crown failures, biological and prosthetic complications, radiographic marginal bone level changes (MBL), probing pocket depth (PPD) and bleeding on probing (BOP). Clinical data were collected at baseline (implant insertion) and 1 year after implant placement (9 months after initial loading). Results: After 1 year of follow-up, no patients dropped out, no implants failed, and no complications occurred. The mean MBL at the 1-year follow-up was 0.28 ± 0.21 mm in the SC group and 0.93 ± 0.37 mm in the BL group. While the difference in MBL was statistically significant between the two treatment groups (difference 0.65 ± 0.34; 95% CI = 0.59 to 1.01; P = 0.0001), the soft-tissue parameters were not statistically different. The mean PPD was 2.63 ± 2.4 in the SC group and 2.40 ± 0.70 in the BL group (P = 0.419) and mean BOP was 0.50 ± 0.71 in the SC group and 0.40 ± 0.70 in the BL group (P = 0.754). Conclusions: The smooth-collar implants inserted supracrestally showed 0.7 mm less radiographic marginal bone loss compared with implants inserted at the bone level 9 months after loading. Keywords: bone level, dental implants, machined collar. single implant, supracrestally Conflict of interest statement: This study was partially supported in term of products by Nobel Biocare (Grant 2013-1215).

Purpose: The primary objective of the present controlled study was to determine the accuracy and precision of intraoral radiography in assessing interproximal bone defect morphology in patients suffering from periodontal disease as well as in patients with peri-implantitis. A secondary objective was to evaluate the possible impact of clinical experience on accuracy and precision. Materials and methods: The study sample comprised a total of 99 interproximal bony defects (40 patients) needing surgical treatment. Forty-nine defects were periodontal (17 patients), while the remaining 50 were peri-implant defects (23 patients). Following reflection of a mucoperiosteal flap and removal of granulation tissue, the type of bone defect as classified by Goldman and Cohen (1958) was determined. This intrasurgical registration was considered the true bone defect morphology. An intraoral radiograph was taken for each interproximal site. Twenty clinicians determined the bone defect morphology on each intraoral radiograph twice, with a washout period of 3 months. Results: Using the Goldman and Cohen (1958) classification, the overall accuracy of intraoral radiography in assessing interproximal bone defect morphology was slight for teeth/implants (κ = 0.132; 95% CI: 0.091 to 0.173/κ = 0.126; 95% CI: 0.091 to 0.162). Duplicate evaluation indicated fair precision (κ = 0.369; 95% CI: 0.308 to 0.430/κ = 0.355; 95% CI: 0.230 to 0.414). Pooling one-, two- and three-wall defects into one category had a positive impact on accuracy (κ = 0.254; 95% CI: 0.201 to 0.307/κ = 0.387; 95% CI: 0.340 to 0.435), as well as on precision (κ = 0.504; 95% CI: 0.423 to 0.584/κ = 0.560; 95% CI: 0.463 to 0.657). A significant difference between experienced clinicians and trainees was not found (P ≥ 0.285). Conclusions: Intraoral radiography lacks accuracy for assessing interproximal bone defect morphology around teeth and implants. Clinical experience does not seem to influence this. Keywords: bone defect, bone morphology, intraoral radiography, peri-implantitis, periodontal disease

This section presents a brief review of articles on dental implants considered of special interest for the reader, in order to encourage the developing 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.