Stability, marginal bone loss and survival of standard and modified sand-blasted, acid-etched implants in bilateral edentulous spaces: a prospective 15-month evaluation

Objectives: Chemical modification of the already proven sand‐blasted and acid‐etched (SLA) implant had increased its surface wettability and consequent early‐term osseointegration characteristics. The aim of this clinical trial was to compare the stability changes, success, survival, peri‐implant parameters and marginal bone loss (MBL) of the early‐loaded standard (SLA) and modified sand‐blasted, acid‐etched (modSLA) implants. Material and methods: A total of 96 SLA and modSLA implants were placed in a bi‐lateral, cross‐arch position to the jaws of 22 patients. Resonance frequency analysis (RFA) was used to measure the implant stability in the surgery and following healing after 1, 3 and 6 weeks. At the stage of loading, a panoramic X‐ray was obtained and RFA measurement was repeated for all implants. Implants were restored by metal–ceramic crowns and followed for 1 year to determine the success, survival rate, peri‐implant parameters and MBL. Results were compared by one‐ and two‐way ANOVA, log‐rank test and generalized linear mixed models (P<0.05). Results: One modSLA implant was lost after 3 weeks following the surgery yielding to a 100 and 97.91% success rate for SLA and modSLA implants, respectively (P=0.323). At the loading stage, modSLA implants showed significantly lower MBL (0.18 ± 0.05 mm) than SLA implants (0.22 ± 0.06 mm; P=0.002). In the loading stage, RFA value of the modSLA implants (60.42 ± 6.82) was significantly higher than the both implant types in the surgical stage (55.46 ± 8.29 and 56.68 ± 8.19), and following 1 (56.08 ± 7.01 and 55.60 ± 9.07) and 3 weeks of healing (55.94 ± 5.95 and 55.40 ± 6.50 for SLA and modSLA implants, respectively). Conclusions: modSLA implants demonstrated a better stability and a reduced MBL at the loading stage. Both SLA and modSLA implants demonstrated a favorable success and survival at the end of 15‐month follow‐up. To cite this article :
Karabuda ZC, Abdel‐Haq J. Arιsan V. Stability, marginal bone loss and survival of standard and modified sand‐blasted, acid‐etched implants in bilateral edentulous spaces: a prospective 15‐month evaluation.
Clin. Oral Impl. Res. 22 , 2011; 840–849
doi: 10.1111/j.1600‐0501.2010.02065.x     

Sinus bone formation and implant survival after sinus membrane elevation and implant placement: a 1- to 6-year follow-up study

Objectives: To investigate the long‐term clinical and radiographic results of the maxillary sinus membrane elevation technique where implants were inserted in a void space created by the elevation of the sinus membrane without adding any graft material. Materials and methods: A total of 84 patients were subjected to 96 membrane elevation procedures and simultaneous placement of 239 implants. Changes of intra‐sinus and marginal bone height in relation to the implants were measured in intraoral radiographs taken at insertion, after 6 months of healing, after 6 months of loading and then annually. Computerized tomography was performed pre‐surgically and 6 months post‐surgically. Resonance Frequency Analyses measurements were performed at the time of implants placement, at abutment connection and after 6 months of loading. The implant follow‐up period ranged from a minimum of one to a maximum of 6 years after implants loading. Results: All implants were stable after 6 months of healing. A total of three implants were lost during the follow‐up period giving a survival rate of 98.7%. Radiography demonstrated on average 5.3±2.1 mm of intra‐sinus new bone formation after 6 months of healing. RFA measurements showed adequate primary stability (implant stability quotient 67.4±6.1) and small changes over time. Conclusion: Maxillary sinus membrane elevation and simultaneous placement of implants without the use of bone grafts or bone substitutes result in predictable bone formation with a high implant survival rate of 98.7% during a follow‐up period of up to 6 years. The intra‐sinus bone formation remained stable in the long‐term follow‐up. It is suggested that the secluded compartment allowed for bone formation according to the principle of guided tissue regeneration. The high implant survival rate of 98.7% indicated that the implants sufficiently supported the fixed bridges throughout the study period. This technique reduces the risks for morbidity related to harvesting of bone grafts and eliminates the costs of grafting materials. To cite this article:
Cricchio G, Sennerby L, Lundgren S. Sinus bone formation and implant survival after sinus membrane elevation and implant placement: a 1‐ to 6‐year follow‐up study.
Clin. Oral Impl. Res. 22 , 2011; 1200–1212.
doi: 10.1111/j.1600‐0501.2010.02096.x     

Immediate vs. early loading of dental implants: 3‐year results of a randomized controlled clinical trial

Objectives: The aim of the present study was to test whether or not immediately loaded implants exhibit the same survival rates as early loaded implants. Material and methods: Eleven patients with bilateral free end mandibles were randomly assigned to treatment either with immediately (test) or early loaded implants (control). Test implants received provisionals in occlusion on the day of surgery, control implants 6 weeks later. Parameters assessed included implant stability quotient (ISQ), plaque, prosthesis stability and radiographs at baseline (implant insertion), 1 and 3 years. The statistical analysis was performed by means of Student's paired t‐test and Wilcoxon's signed‐rank test. The level of significance was set at P<0.05. Results: After a mean observation period of 39.8 months (36.7–53.1), three test implants were lost in two patients resulting in a survival rate of 85% compared with 100% for control implants. At baseline, the mean marginal bone level was significantly higher at test implants (mean=0.36 mm, SD ±0.5) compared with control implants (1.08±0.37 mm). For both test and control implants, the bone level significantly decreased from baseline to 3 years (test: 1.51±0.79 mm; control: 0.89±0.94 mm). The bone loss until 3 years was not significantly different between test and control group. There was no significant difference for ISQ both at test and control implants between baseline (test: 63.59±4.62 mm, control: 65.35±7.43 mm) and 3 years (test: 66.47±7.47 mm, control 68.80±8.75 mm). Conclusions: Immediate loading was associated with a lower implant survival rate. Although the test implants were placed with increased sink depth compared with the control implants, the marginal bone levels were not different between test and control at 3 years. To cite this article:
Zembi? A, Glauser R, Khraisat A, Hämmerle CHF. Immediate vs. early loading of dental implants: 3‐year results of a randomized controlled clinical trial.
Clin. Oral Impl. Res. 21 , 2010; 481–489.
doi: 10.1111/j.1600‐0501.2009.01898.x     

Vertical augmentation with interpositional blocks of anorganic bovine bone vs. 7‐mm‐long implants in posterior mandibles: 1‐year results of a randomized clinical trial

Objectives: To evaluate whether 7‐mm‐long implants could be an alternative to longer implants placed in vertically augmented posterior mandibles. Materials and methods: Sixty patients with posterior mandibular edentulism with 7–8 mm bone height above the mandibular canal were randomized to either vertical augmentation with anorganic bovine bone blocks and delayed 5‐month placement of ≥10 mm implants or to receive 7‐mm‐long implants. Four months after implant placement, provisional prostheses were delivered, replaced after 4 months, by definitive prostheses. The outcome measures were prosthesis and implant failures, any complications and peri‐implant marginal bone levels. All patients were followed to 1 year after loading. Results: One patient dropped out from the short implant group. In two augmented mandibles, there was not sufficient bone to place 10‐mm‐long implants possibly because the blocks had broken apart during insertion. One prosthesis could not be placed when planned in the 7 mm group vs. three prostheses in the augmented group, because of early failure of one implant in each patient. Four complications (wound dehiscence) occurred during graft healing in the augmented group vs. none in the 7 mm group. No complications occurred after implant placement. These differences were not statistically significant. One year after loading, patients of both groups lost an average of 1 mm of peri‐implant bone. There no statistically significant differences in bone loss between groups. Conclusions: When residual bone height over the mandibular canal is between 7 and 8 mm, 7 mm short implants might be a preferable choice than vertical augmentation, reducing the chair time, expenses and morbidity. These 1‐year preliminary results need to be confirmed by follow‐up of at least 5 years. To cite this article:
Felice P, Pellegrino G, Checchi L, Pistilli R, Esposito M. Vertical augmentation with interpositional blocks of anorganic bovine bone vs. 7‐mm‐long implants in posterior mandibles: 1‐year results of a randomized clinical trial.
Clin. Oral Impl. Res 21 , 2010; 1394–1403.
doi: 10.1111/j.1600‐0501.2010.01966.x     

Single implants with different neck designs in the aesthetic zone: a randomized clinical trial

Objectives: To compare single implants in the aesthetic zone with different neck designs for marginal bone‐level changes and clinical outcome measures. Materials and methods: Ninety‐three patients with a missing anterior tooth in the maxilla were randomly assigned to be treated with an implant with a 1.5 mm smooth neck (“smooth group”), a moderately rough neck with grooves (“rough group”) or a scalloped moderately rough neck with grooves (“scalloped‐group”). Implants were installed in healed sites and were loaded after 3 months. Follow‐up visits were conducted at 6 and 18 months after implant placement. Results: The scalloped group showed significantly more radiographic bone loss from implant placement to 18 months (2.01 ± 0.77 mm) compared with the smooth group (1.19 ± 0.82 mm) and rough group (0.9 ± 0.57 mm). Furthermore the scalloped group showed significantly deeper pocket depths and a higher bleeding score. There were no between‐group differences in soft tissue levels. Survival rates were 97% for the smooth group and 100% for the rough and scalloped groups (P>0.05). No significant differences in outcome were found between the smooth group and rough group. Conclusion: For anterior tooth replacements, implants with a scalloped neck showed more marginal bone loss and less favourable clinical outcome compared with implants with a 1.5 mm smooth neck or implants with a rough neck. To cite this article:
den Hartog L, Meijer HJA, Stegenga B, Tymstra N, Vissink A, Raghoebar GM. Single implants with different neck designs in the aesthetic zone: a randomized clinical trial.
Clin. Oral Impl. Res. 22 , 2011; 1289–1297.
doi: 10.1111/j.1600‐0501.2010.02109.x     

Crestal bone loss evaluation in osseotite expanded platform implants: a 5-year study

Objective: The aim of this prospective clinical study was to evaluate the survival rates at 5 years of expanded platform implants placed in the anterior zone of the maxilla and immediately restored with single crowns. Materials and methods: Implants incorporating the platform‐switching concept were placed in fresh extraction sockets in the maxillary arch, with each patient receiving a provisional restoration immediately after implant placement. After 15 days, final screwed restorations were inserted. Mesial and distal bone heights were evaluated using digital radiography on the day following implant placement and at 1, 3, 6, 9, 12, 24, 36 months and 5 years. Primary stability was measured with resonance frequency analysis (RFA) using the Osstell Mentor device. Sixty‐four implants were placed in 32 men and 32 women ranging in age between 29 and 60 (mean: 39.64 ± 5.16 years). Results: Mean mesial bone loss was 0.08 mm (SD 0.42). Mean distal bone loss was 0.14 mm (SD 0.56). Over the course of the 5 years, the mean RFA value was 72.5 ± 3.1 SD. Conclusion: The platform‐switched implants remained stable over the course of 5 years and had an overall survival rate of 97.1%. To cite this article:
Calvo‐Guirado J L, Gómez‐Moreno G, López‐Marí L, Guardia J, Negri B, Martínez‐González J M. Crestal bone loss evaluation in osseotite expanded platform implants: a 5‐year study.
Clin. Oral Impl. Res. xx , 2011; 000–000
doi: 10.1111/j.1600‐0501.2010.02130.x     

A 3‐year prospective radiographic evaluation of marginal bone level around different implant systems

Summary The aim of this study was to evaluate the change of marginal bone level radiographically around three different implant systems after 3 years in function. Fifty‐four patients were included and randomly assigned to three treatment groups of rough‐surface implants (TiUnite, n = 37), hybrid of smooth and rough‐surface implants (Restore, n = 38) and rough surface with microthread implants (Hexplant, n = 45). Clinical and radiographic examinations were conducted at the time of implant loading (baseline), 1 and 3 years after loading. A three‐level mixed‐effect analysis of covariance (ancova ) was used to test the significance of the mean marginal bone change of the three implant groups. A total 120 of 135 implants completed the study. None of the implants failed to integrate. Significant differences were noted in the marginal bone loss recorded for the three groups (P < 0·0001). At 3 years, the rough surface with microthread implants had a mean crestal bone loss of 0·59 ± 0·30 mm; the rough‐surface implants, 0·95 ± 0·27 mm; and the hybrid surface implants, 1·05 ± 0·34 mm. Within the limitations of this study, rough‐surface implants with microthread at the coronal part might have a long‐term positive effect in maintaining the marginal bone level against functional loading in comparison with implants without these two features.     

Long‐term,retrospective evaluation (implant and patient‐centred outcome) of the two‐implant‐supported overdenture in the mandible. Part 2: marginal bone loss

Objective: In part 2 of this long‐term, retrospective study on the two‐implant‐supported overdenture in the mandible, the annual marginal bone loss was evaluated in detail and parameters, with a significant effect on the annual bone loss, were verified. Material and methods: For all 495 patients with an overdenture in the mandible at least 5 years in function, data up to their last follow‐up visit had been collected, including long‐cone radiographs (taken at the abutment connection and after years 1, 3, 5, 8, 12 and 16 of loading) and probing data at their last evaluation. General information (medical history, implant data, report on surgery) was retrieved from the patient's file. Two hundred and forty‐eight patients had been clinically examined recently. For the others, information on bone level and probing depths were retrieved from the patient's files, as all patients had been enrolled in our annual follow‐up schedule. Results: The mean annual bone loss on a site level (without considering the first year of bone remodelling) after 3 years of loading was 0.08 mm/year (SD=0.22, n=1105), after 5 years of loading 0.07 mm/year (SD=0.14, n=892), after 8 years of loading 0.06 mm/year (SD=0.12, n=598), after 12 years 0.04 mm/year (SD=0.07, n=370) and 0.05 mm/year (SD=0.05, n=154) after 16 years of loading. Ongoing bone loss was seen in a number of implants (n=26) with the annual bone loss exceeding 0.2 mm. Some factors clearly showed a significant impact on bone loss: smoking (≥10 cigarettes/day), GBR, the presence of dehiscence and bone quantity(the latter only during the first year). The probing data showed a favourable condition, with <1.2% of the approximal pockets being ≥6 mm, and 4.1%=5 mm. Conclusions: The mean annual bone loss over the study period was <0.1 mm/year after the first year of loading. However, a small number (2.5%) of the implants showed continuing bone loss. To cite this article :
Vercruyssen M, Quirynen M. Long‐term, retrospective evaluation (implant and patient‐centred outcome) of the two‐implants‐supported overdenture in the mandible. Part 2: marginal bone loss.
Clin. Oral Impl. Res. 21 , 2010; 466–472.
doi: 10.1111/j.1600‐0501.2009.01902.x     

Narrow‐ and regular‐diameter implants in the posterior region of the jaws to support single crowns: A 3‐year split‐mouth randomized clinical trial

Objectives

The objective of this 3‐year split‐mouth randomized controlled clinical study was to compare narrow‐diameter implants (NDIs) to regular‐diameter implants (RDIs) in the posterior region of the jaws (premolars and molars) in regards to (i) the marginal bone level (MBL) and (ii) implant and prosthesis survival and success rates.

Material and Methods

A total of 22 patients were included in the study. Each patient received at least one implant of each diameter (Ø3.3 and Ø4.1 mm), placed either in the maxilla or mandible to support single crowns. A total 44 implants (22 NDIs and 22 RDIs) were placed and included in the study. Twenty‐one implants were placed in the premolar, whereas 23 were placed in molar areas. Radiographic evaluations to access the MBL were performed immediately after implant placement, 1 and 3 years after implant loading. Peri‐implant clinical variables including probing pocket depth (PPD) and bleeding on probing (BoP) were obtained after crown delivery, 1 and 3 years after loading. Furthermore, the survival and success rates of the implants and prosthesis were also evaluated.

Results

Twenty patients were able to complete the study. There was no statistically significant difference regarding MBL between groups at implant placement (p = .084), 1‐year (p = .794) and 3‐year (p = .598) time intervals. The mean peri‐implant bone loss at 3‐year follow‐up was ?0.58 ± 0.39 mm (95% CI: ?0.751 to ?0.409) and ?0.53 ± 0.46 mm (95% CI: ?0.731 to ?0.329) for NDIs and RDIs, respectively. BoP was present at 15% and 10% of NDIs and RDIs, respectively, at 3‐year follow‐up. PPD >5 mm was observed in 5% and 0% of the implants of NDIs and RDIs, respectively, at 3‐year follow‐up. At the 3‐year examination, the implant success rates were in the NDIs and RDIs sites, respectively, 95% and 100%. The corresponding values for prosthesis success rates were 90% for NDIs and 95% for RDIs.

Conclusion

The present study demonstrated that NDIs placed to support single crowns in the posterior region did not differ to RDIs in regards to MBL, implant survival, and success rates.     

A 10‐year retrospective analysis of radiographic bone‐level changes of implants supporting single‐unit crowns in periodontally compromised vs. periodontally healthy patients

Aim: To compare the 10‐year peri‐implant bone loss (BL) rate in periodontally compromised (PCP) and periodontally healthy patients (PHP) around two different implant systems supporting single‐unit crowns. Materials and methods: In this retrospective, controlled study, the mean BL (mBL) rate around dental implants placed in four groups of 20 non‐smokers was evaluated after a follow‐up of 10 years. Two groups of patients treated for periodontitis (PCP) and two groups of PHP were created. For each category (PCP and PHP), two different types of implant had been selected. The mBL was calculated by subtracting the radiographic bone levels at the time of crown cementation from the bone levels at the 10‐year follow‐up. Results: The mean age, mean full‐mouth plaque and full‐mouth bleeding scores and implant location were similar between the four groups. Implant survival rates ranged between 85% and 95%, without statistically significant differences (P>0.05) between groups. For both implant systems, PCP showed statistically significantly higher mBL rates and number of sites with BL≥3 mm compared with PHP (P<0.0001). Conclusions: After 10 years, implants in PCP yielded lower survival rates and higher mean marginal BL rates compared with those of implants placed in PHP. These results were independent of the implant system used or the healing modality applied. To cite this article:
Matarasso S, Rasperini G, Iorio Siciliano V, Salvi GE, Lang NP, Aglietta M. A 10‐year retrospective analysis of radiographic bone‐level changes of implants supporting single‐unit crowns in periodontally compromised vs. periodontally healthy patients.
Clin. Oral Impl. Res. 21 , 2010; 898–903.
doi: 10.1111/j.1600‐0501.2010.01945.x     

Prospective study with a 2‐year follow‐up on immediate implant loading in the edentulous mandible with a definitive restoration using intra‐oral welding

Objectives: The aim of this prospective study was to evaluate the concept of intra‐oral welding as a suitable technique for the fabrication of a restoration for edentulous mandibles on the same day as surgery using tapered connection implants. Material and methods: Each of 20 patients had an edentulous mandible and received four inter‐foraminal, tapered connection implants. All implants were immediately loaded with a fixed restoration supported by an intra‐orally welded titanium framework. Final abutments were connected to the implants and then a titanium bar was welded to them using an intra‐oral welding unit. This framework was used as a support for the final restoration, which was fitted on the same day as implant placement. Mean marginal bone loss and radiographically detectable alteration of the welded framework were assessed using periapical radiographs immediately after surgery, and at 6‐, 12‐ and 24‐month follow‐up examinations. Results: Seven males and 13 females, with an average age of 56.5 years (SD=15.1; n=20), were consecutively treated with 80 immediately loaded implants. No fracture or radiographically detectable alteration of the welded frameworks was evident. All implants osseointegrated and a 100% implant survival rate was achieved at the 24‐month follow‐up. The accumulated mean marginal bone growth was 0.21 mm (SD 0.25, n=80). The average pocket probing depth was 1.38 mm (SD 0.41). Conclusions: The intra‐oral welding technique applied to the delivery of a final restoration of the edentulous mandible over immediately restored tapered connection implants seems to have no adverse effect on marginal bone loss and implant survival. To cite this article:
Degidi M, Nardi D, Piattelli A. Prospective study with a 2‐year follow‐up on immediate implant loading in the edentulous mandible with a definitive restoration using intra‐oral welding.
Clin. Oral Impl. Res. 21 , 2010; 379–385.
doi: 10.1111/j.1600‐0501.2009.01865.x     

Reconstruction of the atrophic edentulous maxilla with free iliac crest grafts and implants: a 3-year report of a prospective clinical study

Purpose: The purpose of this study was to perform a longitudinal follow-up study of implant stability in grafted maxillae with the aid of clinical, radiological, and resonance frequency analysis (RFA) parameters. Materials and Methods: The atrophic edentulous maxillae in 29 patients were reconstructed with free iliac crest grafts using onlay/inlay or interpositional grafting techniques. The endpoint of the resorption pattern in the maxilla determined the grafting technique used. Endosteal implants were placed after 6 months of bone-graft healing. Implant stability was measured four times using RFA: when the implants were placed, after 6 to 8 months of healing, after 6 months and 3 years of bridge loading. Individual checkups were performed at the two later RFA registrations after removal of the supraconstructions (Procera® Implant Bridge, Nobel Biocare AB, Göteborg, Sweden). Radiological follow up of marginal bone level was performed annually. Results: Twenty-five patients remained for the follow-up period. A total of 192 implants were placed and with a survival rate of 90% at the 3-year follow up. Women and an implant position with a class 6 resorption prior to reconstruction were factors with significant increased risk for implant failure (multivariate logistic regression). Twelve of the 20 failed implants were lost before loading (early failures). The change in the marginal bone level was 0.3 ± 0.3 mm between baseline (bridge delivery) and the 3-year follow up. The implant stability quotient (ISQ) value for all implants differed significantly between abutment connection (60.2 ± 7.3) and after 6 months of bridge loading (62.5 ± 5.5) (Wilcoxon signed ranks test for paired data, p=.05) but were nonsignificant between 6 months of bridge loading and 3 years of bridge loading (61.8 ± 5.5). There was a significant difference between successful and failed implants when the ISQ values were compared for individual implants at placement (Mann-Whitney U test, p=.004). All 25 patients were provided with fixed implant bridges at the time of the 3-year follow up. Conclusion: This clinical follow up using radiological examinations and RFA measurements indicates a predictable and stable long-term result for patients with atrophic edentulous maxillae reconstructed with autogenous bone and with delayed placement of endosteal implants. The ISQ value at the time of placement can probably serve as an indicator of level of risk for implant failure.     

Evaluation of Clinical Outcomes and Bone Loss around Titanium Implants with Oxidized Surface: Six‐Year Follow‐Up Results from a Prospective Case Series Study

Purpose: The aim of this prospective study was to assess long‐term clinical outcomes and peri‐implant bone level changes around oxidized implants supporting partial fixed rehabilitations. Materials and Methods: Twenty‐two partially edentulous patients were included in the study. A total of 33 fixed rehabilitations were placed, supported by 54 titanium implants with oxidized microtextured surface. Prostheses were delivered after 3 and 6 months of implant placement in the mandible and maxilla, respectively. Patients were scheduled for follow‐up at 6 and 12 months and then yearly. At each follow‐up, plaque level and bleeding scores were assessed and periapical radiographs were taken. The main outcomes were prosthesis success, implant survival, implant success, and marginal bone level change. Results: Three patients were excluded from the study because they did not attend the 1‐year follow‐up. Nineteen patients, accounting for 49 implants, were followed for at least 6 years after prosthesis delivery. The mean follow‐up duration was 81.8 months (range 75–96 months). One mandibular single‐tooth implant failed after 1 year in a smoker woman. Cumulative implant survival and success at 6 years were 98.0% and 95.9%, respectively. Prosthesis success was 96.7%. The mean peri‐implant bone loss at 6 years was 0.76 ± 0.47 mm. Not significantly (p = .75) greater bone loss was found in the maxilla (0.78 ± 0.14 mm, n = 19) as compared with the mandible (0.74 ± 0.59 mm, n = 30). In the maxilla, bone loss was significantly greater around implants supporting partial prostheses as compared with single‐tooth implants (p = .03). Full patient satisfaction was reported. Conclusion: Implants with oxidized microtextured surface may achieve excellent long‐term clinical outcomes in the rehabilitation of partial edentulism.     

Clinical Outcomes of an Osteotome Technique and Simultaneous Placement of Neoss Implants in the Posterior Maxilla

Background: Insufficient bone volume often hamper placement of dental implants in the posterior maxilla. Purpose: The aim of the present clinical study was to evaluate retrospectively the clinical outcome of implant placement in the resorbed posterior maxilla using an osteotome technique without adding any grafting material. Materials and Methods: Twenty patients with 5 to 9 mm of residual alveolar bone height in the posterior maxilla received twenty‐nine implants (Neoss Ltd., Harrogate, UK) using an osteotomy technique without bone grafts. Intraoral radiographs were taken before and after implant placement, at the time of loading and after 11 to 32 months of loading (mean 16.4 months), to evaluate bone formation below the sinus membrane and marginal bone loss. Implant stability measurements (Osstell^TM, Gothenburg, Sweden) were performed after implant installation and at abutment connection 5 months later. All implants were installed with the prosthetic platform level with the bone crest. Results: No implant was lost giving a survival rate of 100% after a mean follow‐up time of 16.4 months. The average vertical bone height was 7.2 ± 1.5 mm at placement and 10.0 ± 1.0 mm after 11 to 32 months. The average increase of 2.8 ± 1.1 mm was statistically significant. There was a statistically significant improvement in implant stability from 70.7 ± 9.2 implant stability quotient (ISQ) at placement to 76.7 ± 5.7 ISQ at abutment connection, 5 months later. The mean marginal bone loss amounted to 0.7 ± 0.3 mm after 11 to 32 months of loading. Conclusion: It is concluded that the osteotome technique evaluated resulted in predictable intrasinus bone formation, firm implant stability, and good clinical outcomes as no implants were lost and minimal marginal bone loss was observed.     

Clinical and radiographic performance of delayed-immediate single-tooth implant placement associated with peri-implant bone defects. A 2-year prospective, controlled, randomized follow-up report

Objectives: The aim of the present study was to compare the delayed‐immediate (Im) and the delayed (De) protocols for placement of single‐tooth implants. Material and methods: After allocation to the Im and De groups by random, 46 patients were treated with a single‐tooth implant with acid etched surfaces (Osseotite^®) in the anterior or pre‐molar region of the maxilla or the mandible on average 10 days (Im) or 3 months (De) following tooth extraction, respectively. Forty‐one patients attended a follow‐up visit 2 years after implant placement corresponding to 1½ years of loading of the implant restorations. Peri‐implant and prosthetic parameters were evaluated clinically and marginal bone levels measured on radiographs. Results: Three implants were lost, all before mounting of the crown. None of the implant restorations had failed after 1½ years of function. Probing pocket depths were reduced by up to 1.4 mm on average from the time of loading to the 2‐year follow‐up and at that time, no significant difference between the Im and De groups was found (4.2 versus 4.1 mm). A statistically significant radiographic marginal bone loss had occurred in the Im group (mean=0.8 mm) as well as in the De group (mean=0.7 mm) in the follow‐up period. However, a mean marginal bone level of approx. 1.5 mm in both groups measured from the implant–abutment junction was found to be acceptable. It was demonstrated that probing pocket depths and marginal bone levels after 1½ years of loading of the implant‐retained crowns were not influenced by the presence of peri‐implant bone defects immediately after implant placement. Furthermore, no severe prosthodontic complications, such as screw loosening or porcelain fractures, arose in this study material. Conclusion: High success rates of single‐tooth implants after 1½ years of function were achieved using the delayed‐immediate and delayed implant placement techniques.     

Bone alterations at implant‐supported FDPs in relation to inter‐unit distances: a 5‐year radiographic study

Objectives: The aim of this 5‐year study was to longitudinally evaluate bone alterations around implants with a conical implant–abutment interface in relation to implant–tooth and inter–implant distances. Material and methods: The patient sample comprised 43 partially dentate patients with a total of 48 implant‐supported fixed dental prostheses (FDPs) supported by 130 Astra Tech^® implants. Following FDP placement (baseline), the patients were enrolled in an individually designed supportive care program. Radiographic examinations were performed at the time of FDP installation, 1 and 5 years of follow‐up. Variables regarding implant position and proximal bone topography at tooth/implant units (n=36) and implant/implant units (n=67) were assessed with the use of a software program after scanning of the radiographs. Results: At tooth/implant units, the mean 5‐year marginal bone loss at the tooth, the implant and the mid‐proximal bone crest was 0.1, 0.4 and 0.2 mm, respectively. The mean longitudinal bone loss at the implant/implant units was 0.5 mm at the implants and 0.3 mm mid‐proximally. Multilevel regression analysis revealed that at implant/implant units, the change in the bone‐to‐implant contact level was a significant predictor with regard to the 5‐year mid‐proximal bone‐level change, whereas the horizontal inter‐unit distance showed a borderline significance (P=0.052). At tooth/implant units, no statistically significant associations were identified. Conclusions: The results of this 5‐year study revealed differences between inter‐implant and tooth–implant proximal areas with regard to bone crest alterations and associated factors. To cite this article:
Chang M, Wennström JL. Bone alterations at implant‐supported FDPs in relation to inter‐unit distances: a 5‐year radiographic study.
Clin. Oral Impl. Res. 21 , 2010; 735–740.
doi: 10.1111/j.1600‐0501.2009.01893.x     

A Retrospective Evaluation of the Survival Rates of Splinted and Non‐Splinted Short Dental Implants in Posterior Partially Edentulous Jaws

Background: The aim of the present study is to evaluate the survival rate and bone loss around short implants (≤10 mm) supporting splinted or non‐splinted posterior prostheses during a follow‐up period of 3 to 16 years. Methods: A total of 453 implants from 198 patients was divided into splinted or non‐splinted groups. Implant survival rate was calculated for each group, and potential risk was represented as odds ratio (OR). The final linear distance from implant platform level to the first bone‐to‐implant contact was compared to this same reference just after loading by digital periapical radiographs to determine the marginal bone loss (BL). Results: The splinted group comprised 219 implants in 86 patients, whereas the non‐splinted group included 234 implants from 112 patients. The mean follow‐up period was 9.7 ± 3.7 years. Although different success rates were found for splinted (97.7%) and non‐splinted (93.2%) groups, they exhibited similar BL (1.22 ± 0.95 mm and 1.27 ± 1.15 mm, respectively). The success of splinted implants was associated with no other variable, whereas non‐splinted implants exhibited higher risk of failure when placed in men (OR = 3.2) and when implants shorter than 10 mm were used (OR = 3.6 and 4.1 for 8.5 mm and 7 mm, respectively). Regardless of group, 71.4% of the unsuccessful implants failed before the end of the first year after loading. Conclusion: Non‐splinted posterior short implants had a somewhat lower success rate than splinted short implants, and the failure rate in non‐splinted short implants appeared to be greater in males as well as in implants ≤10 mm.     

Radiological and clinical follow-up of machined- and anodized-surface implants after mean functional loading for 33 months

Abstract: The purpose of this retrospective study was to compare peri‐implant bone loss and mucosal conditions around machined‐surface (MS) and anodized‐surface (AS) interforaminal implants in the mandible at least 30 months after placement. Fifty patients, each treated with four interforaminal screw‐type implants consecutively, were included. Thirty‐one patients (62%) with a total number of 124 implants (64 MS and 60 AS implants, both Brånemark type MKIII) were available for follow‐up. Rotational panoramic radiographs were used for evaluating marginal bone loss. Clinically, marginal plaque index (mPI), bleeding on probing (BOP) and pocket probing depth (PPD) were evaluated. AS implants showed significantly less marginal bone loss than MS implants (−1.17±0.13 vs. −1.42±0.13 mm; P=0.03). Marginal bone loss around distal implants was less pronounced at AS implants (−1.05±0.14 mm) when compared with MS implants (−1.46±0.14 mm; P=0.05). Within the smoking group, there was less peri‐implant bone loss around AS implants than around MS implants (−1.08±0.27 vs. −1.83±0.2; P=0.04). No differences between MS and AS implants were found with respect to mPI (57% vs. 67%), BOP (21% vs. 17%) and mean PPD (2.59±0.29 vs. 2.56±0.28 mm). Overall, both types of implants, in combination with bar‐supported overdentures, can produce excellent long‐term results in the interforaminal edentulous mandible with less peri‐implant bone loss around rough implant surfaces, which had beneficial effects at distal implants and in smokers.     

Immediately restored one-piece single-tooth implants with reduced diameter: one-year results of a multi-center study

Objectives: The aim of the present multi‐center study was to evaluate the treatment outcome of immediately restored one‐piece single‐tooth implants with a diameter of 3 mm after 1 year. Material and methods: A total of 57 one‐piece implants (NobelDirect^® 3.0) were inserted in 47 patients (26 females, 21 males) with a mean age of 31 years (range: 17–76 years) at five different centers. The implants replaced maxillary lateral incisors and mandibular incisors. The implants were placed either in conjunction with tooth extraction or in healed sites, and all implants were immediately restored with a provisional resin crown. If needed, the abutment part of the implant was prepared before crown cementation. The permanent crown was placed after 1.9–14.5 months. Radiographs were taken at implant insertion as well as after 6 and 12 months to evaluate the peri‐implant marginal bone level and bone loss. Moreover, plaque, bleeding on probing and complications were assessed. Results: A total of 44 patients (23 females, 21 males) with 54 implants were available for the 1‐year follow‐up. One implant was lost, thus the 1‐year implant survival was 98%. A statistically significant mean marginal bone loss was observed between baseline and 6 months (1.1 mm, range: ?0.7 to 4.4 mm; n=49) and between baseline and 12 months (1.6 mm, range: ?0.8 to 4.6 mm; n=50). A total of 18% of the implants were characterized by a bone loss of more than 3 mm. No bleeding on probing was observed around 83% of the implants. Plaque was registered at 15% of the implants. The most common complications were related to the provisional crown, i.e. fracture (n=3) and loss of retention (n=3). Conclusions: A high 1‐year implant survival was observed in the present study. However, the excessive peri‐implant marginal bone loss around several implants indicates that this implant should be used with caution until further studies have been conducted. To cite this article:
Zembi? A, Johannesen LH, Schou S, Malo P, Reichert T, Farella M, Hämmerle CHF. Immediately restored one‐piece single‐tooth implants with reduced diameter: one‐year results of a multi‐center study.
Clin. Oral Impl. Res. 23 , 2012; 49–54.
doi: 10.1111/j.1600‐0501.2011.02174.x     

The effect of different implant neck configurations on soft and hard tissue healing: a randomized-controlled clinical trial

Objective: To compare the soft and hard tissue healing and remodeling around tissue‐level implants with different neck configurations after at least 1 year of functional loading. Material and methods: Eighteen patients with multiple missing teeth in the posterior area received two implants inserted in the same sextant. One test (T) implant with a 1.8 mm turned neck and one control (C) implant with a 2.8 mm turned neck were randomly assigned. All implants were placed transmucosally to the same sink depth of approximately 1.8 mm. Peri‐apical radiographs were obtained using the paralleling technique and digitized. Two investigators blinded to the implant type‐evaluated soft and hard tissue conditions at baseline, 6 months and 1 year after loading. Results: The mean crestal bone levels and soft tissue parameters were not significantly different between T and C implants at all time points. However, T implants displayed significantly less crestal bone loss than C implants after 1 year. Moreover, a frequency analysis revealed a higher percentage (50%) of T implants with crestal bone levels 1–2 mm below the implant shoulder compared with C implants (5.6%) 1 year after loading. Conclusion: Implants with a reduced height turned neck of 1.8 mm may, indeed, lower the crestal bone resorption and hence, may maintain higher crestal bone levels than do implants with a 2.8 mm turned neck, when sunk to the same depth. Moreover, several factors other than the vertical positioning of the moderately rough SLA surface may influence crestal bone levels after 1 year of function. To cite this article:
Tan WC, Lang NP, Schmidlin K, Zwahlen M, Pjetursson BE. The effect of different implant neck configurations on soft and hard tissue healing: a randomized‐controlled clinical trial.
Clin. Oral Impl. Res. 22 , 2011; 14–19.
doi: 10.1111/j.1600‐0501.2010.01982.x