European Journal of Oral Implantology最新文献

Aim: To review available evidence in scientific literature on oral implants of severely reduced length or diameter.

Materials and methods: Electronic and hand searches up to May 2017 were performed in order to identify clinical investigations providing implant survival and/or marginal bone resorption data for extra-short implants < 7.0 mm in length and extra-narrow implants < 3.5 mm in diameter (excluding one-piece mini-implants).

Results: A total of 2929 extra-short implants and 3048 extra-narrow diameter implants were investigated in 53 and 29 clinical studies, respectively. Shorter implants between 4.0 mm and 5.4 mm in length showed comparable results to implant lengths of 5.5 mm to 6.5 mm (95.1% vs. 96.4%, P = 0.121) and no difference regarding marginal bone resorption (0.7 mm vs 0.5 mm, P = 0.086). Implant lengths of 5.5 mm to 6.5 mm, however, performed significantly better in the mandible compared with the maxilla (P = 0.010). Smaller diameters between 3.0 mm and 3.25 mm yielded a significantly lower survival rate of 94.3% than wider implants of 3.3 mm to 3.4 mm diameter (97.7%, P < 0.001), while marginal bone resorption did not differ (0.4 mm vs 0.5 mm, P = 0.447).

Conclusions: The results of the present literature review suggest that extra-short and extra-narrow-diameter implants show satisfactory survival rates of around 95% and little marginal bone resorption of around 0.5 mm after a mean follow-up of 3 years. However, implant lengths < 7 mm in the maxilla and < 5.5 mm in the mandible as well as diameters < 3.3 mm may increase early failure rates.

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.

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.

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% 0.1

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.

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.

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.

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.

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.