Volume gain and stability of peri-implant tissue following bone and soft tissue augmentation: 1-year results from a prospective cohort study

Objectives: The aim of the present study was to evaluate the dimensional changes of peri‐implant tissues obtained by implant placement, bone and soft tissue augmentation, prosthetic reconstruction and 1 year of function using a new, non‐invasive method for volumetric measurements. Materials and Methods: In 16 patients, the missing central or lateral maxillary incisor was reconstructed with an implant‐supported single crown. Impressions were taken before (t1), after implant placement with guided bone regeneration using DBBM and a PTFE membrane (t2), after soft tissue augmentation (t3), immediately after crown placement (t4) and 1 year later (t5). The cast models were optically scanned and digitally superimposed allowing qualitative and quantitative analysis of alterations of the labial peri‐implant tissue contour. In addition, the crown length and papilla height were measured at crown placement (t4) and after 1 year (t5). Results: Fifteen patients were available for recall after 1 year. During therapy, a mean gain in distance in the labial direction of 1.27±0.67 mm was observed after the surgical procedures. One year after crown insertion, a mean loss of 0.04±0.31 mm in the labial direction was recorded. During the same period, the crown length increased by a mean of 0.22±0.57 mm and the papilla height by 0.07±0.61 mm. The degree and pattern of tissue change following crown insertion were highly variable between individuals, irrespective of the amount and quality of previously augmented tissues. Conclusions: The clinical procedures were effective in augmenting peri‐implant tissue volume that remained stable to a high degree within 1 year after crown insertion. Large inter‐individual variations regarding the tissue alterations were observed. To cite this article:
Schneider D, Grunder U, Ender A, Hämmerle CHF, Jung RE. Volume gain and stability of peri‐implant tissue following bone and soft tissue augmentation: 1‐year results from a prospective cohort study
Clin. Oral Impl. Res. 22 , 2011; 28–37.
doi: 10.1111/j.1600‐0501.2010.01987.x     

Immediate Single‐Tooth Implant Placement in Bony Defects in the Esthetic Zone: A 1‐Year Randomized Controlled Trial

Background: This study aims to assess, with regard to marginal bone level (MBL), whether the outcome of immediate implant placement in bony defects in the esthetic zone was non‐inferior to delayed implant placement after 1 year. Methods: Forty patients with a failing tooth in the esthetic zone and a labial bony defect of ≥5 mm after removal of a tooth were randomly assigned for immediate (n = 20) or delayed (n = 20) implant placement. Second‐stage surgery and provisionalization occurred after 3 months of healing. Follow‐up was at 1 month and 1 year after definitive crown placement. The study was powered to detect a difference in MBL of >0.9 mm. Buccal bone thickness, soft tissue peri‐implant parameters, esthetic indices, and patient satisfaction were also assessed. Results: One year after definitive crown placement, MBL loss was 0.56 ± 0.39 mm mesially and 0.74 ± 0.51 mm distally for the immediate placement group and 0.51 ± 0.43 mesially and 0.54 ± 0.45 distally mm for the delayed placement group, respectively (not significant). Regarding differences in means, non‐inferiority was observed after 1 year (difference in mean for immediate versus delayed: mesially 0.04 mm [95% confidence interval (CI) = ?0.22 to 0.30 mm, P = 0.40]; distally 0.21 mm [95% CI = ?0.10 to 0.51 mm, P = 0.58]). No significant differences in the other outcome variables were observed. Conclusions: Immediate implant placement with delayed provisionalization was non‐inferior to delayed implant placement with delayed provisionalization in labial bony defects of ≥5 mm regarding change in MBL. Although not powered for other outcome variables, no clinically relevant differences were observed in these variables.     

The effect of internal versus external abutment connection modes on crestal bone changes around dental implants: a radiographic analysis

Background: To the best of our knowledge, the influence of external versus internal implant–abutment connections on crestal bone remodeling has not been reported. The aim of the present study is to investigate the influence of the abutment connection on peri‐implant crestal bone levels (CBLs) using radiographic recordings. Methods: Radiographic recordings from 40 single‐tooth implants (20 external and 20 internal octagonal connections; one implant/patient) in 40 patients (15 males and 25 females; mean age: 54.3 years) were selected for analyses. The radiographic evaluation included the following: 1) linear bone change (LBC); 2) dimensional change (DC); and 3) angle between the implant and adjacent bone (AIB). Differences in LBC, DC, and AIB between implant placement and 1 year after loading for each system were evaluated using a paired t test. Comparison of LBC, DC, and AIB between systems at 1 year after loading was done using analysis of covariance. The significance level was set at P ≤0.05. Results: Radiographic CBLs (LBCs) were reduced at 1 year after loading compared to those at implant placement to reach statistical significance for the external connection (P = 0.000) but not the internal connection (P = 0.939). CBL changes were significantly greater for the external compared to the internal connection (P = 0.000). Similarly, the DC for the external connection was significantly greater compared to that for the internal connection (P = 0.004). Conclusion: Within the limitations of this study, the implant–abutment connection technology appears to have a significant impact on peri‐implant CBLs, with the external connection paralleled by a significant reduction of CBLs.     

One‐Year Outcomes of Neoss Bimodal Implants. A Prospective Clinical,Radiographic, and RFA Study

Background: The Neoss implant system has been available since 2004. Few studies documenting the clinical performance of this implant are available. Purpose: To study the stability and clinical/radiographic outcomes of Neoss implants 1 year of loading when using a two‐stage protocol. Materials and Methods: Ninety (90) consecutive patients scheduled for implant treatment using a two‐stage procedure were enrolled in a prospective follow‐up study. A total of 218 implants (Neoss System, Bimodal surface, Neoss Ltd, Harrogate, UK) in diameters of 3.5, 4.0, and 4.5 mm and in lengths from 7 to 15 mm were placed to support 29 single tooth replacements, 53 partial bridges, 5 full bridges, and 10 overdentures in both jaws. Abutment connection was made after a healing period of 3–4 months. The patients were followed during 1 year of loading with clinical, radiographic, and resonance frequency analysis (Osstell Mentor?, Osstell AB, Gothenburg, Sweden) examinations. Prostheses were removed at the annual check‐up for individual testing of implant stability. Results: Three implant failures were experienced, giving a survival rate of 98.6% after 1 year. A mean bone loss of 0.6 mm (SD 0.8) was observed after 1 year. There was a significant inverse correlation between implant diameter and marginal bone loss (p < .003). The mean implant stability quotient levels were 73.7 (SD 7.6), 74.4 (SD 6.4), and 76.7 (SD 5.2) at placement, abutment connection, and first annual check‐up, respectively. The stability had increased significantly from placement to 1 year (p < .001) and from abutment to 1 year (p < .0001). Implant stability was higher in the mandible than in the maxilla at all time points. There was a significant correlation between bone quality and stability at placement (p < .0001) and abutment connection (p < .001) but not after 1 year. Conclusions: The use of Neoss implants for prosthetic rehabilitation of consecutive edentate patients with different needs resulted in predictable clinical and radiographic outcomes after 1 year of loading. Implant stability measurements revealed a favorable bone tissue reaction to the implants.     

An Analysis of the Effect of a Vent Hole on Excess Cement Expressed at the Crown–Abutment Margin for Cement-Retained Implant Crowns

Purpose: The labial margins of anterior implant‐retained crowns are often positioned subgingivally for a superior esthetic appearance. One of the consequences of subgingival margins is the increased risk of leaving excess cement behind following cementation. This can lead to potential problems, including peri‐implant inflammation, soft tissue swelling, soreness, bleeding or suppuration on probing, and bone loss. The purpose of this laboratory study was to investigate the effect of placement, location, and diameter of a vent hole on the amount of cement being expressed at the margin of an anterior implant abutment‐retained crown. Materials and Methods: Three implant crown copings were fabricated to fit on the same custom abutment. Three vent diameters (0.75, 1.25, and 1.65 mm) and three locations on the palatal surface of the coping (cervico‐palatally, mid‐palatally, inciso‐palatally) were chosen for vent hole placement. For each test, the coping was cemented onto the abutment under standardized conditions. A preweighed thin coating of cement was applied to the fit surface of the coping. The amount of cement expressed at the margin and vent hole was measured by weight and calculated as a proportion of the amount of cement placed in the coping before seating. The procedure was completed 15 times for each variable. The results were statistically analyzed using univariate ANOVA with post hoc Bonferroni‐adjusted independent samples t‐tests. Results: The presence of a vent hole influenced the proportion of cement expressed at the coping margin (p < 0.05). The location of a vent hole influenced the proportion of cement expressed at the coping margin (p < 0.05), with the exception of the mid‐palatal and inciso‐palatal positioning where there was no significant difference (p= 0.61) between groups. The diameter of the vent hole did not significantly influence the proportion of cement expressed at the coping margin (p= 0.096). Conclusions: When using anterior cement‐retained implant crowns, the use of a 0.75‐mm mid‐palatal or inciso‐palatal vent hole to minimize the amount of cement expressed at the margin during cementation should be considered.     

One-year outcome of narrow diameter blasted implants for rehabilitation of maxillas with knife-edge resorption

Objectives: This study aimed at assessing the clinical outcome of narrow diameter implants in the treatment of knife‐edge edentulous maxillas of adequate bone height but inadequate width (class IV of Cawood and Howell). Material and methods: Twelve consecutive patients (eight women and four men, mean age 58 years) with class IV atrophic edentulous maxillas were included in the study. Seventy‐three microthreaded TiO₂‐blasted implants were placed and the resonance frequency measured. All the implants had a diameter of 3.5 mm. After 6 months of submerged healing, fixed implant‐supported prostheses were delivered to the patients and resonance frequency and radiographic examinations performed. After the first year of loading, the implant outcome was again evaluated clinically, radiographically and with resonance frequency analysis. Results: All the implants were followed up to 1 year of loading and their survival rate was 100%. Bone loss after 1 year of loading was (mean±SD) 0.30±0.13 mm. Stability values were (mean±SD) 63±5.8 ISQ at placement, 60±4.7 ISQ at the abutment connection and 61±5 ISQ after 1 year of loading. A significant difference resulted between placement and abutment connection values (P=0.03). Conclusions: According to the present study, narrow implants may be used to restore edentulous maxillas with atrophies of class IV of Cawood and Howell. When planning the treatment of edentulous maxillas with such a resorption pattern, this possibility has to be considered as an alternative to more demanding grafting techniques.     

Measurements of buccal tissue volumes at single-implant restorations after local bone grafting in maxillas: a 3-year clinical prospective study case series

Purpose: The purpose of this study was to measure changes in buccal and proximal tissue volumes after local bone grafting and single‐implant treatment. Materials and Methods: Ten patients were provided with buccal bone grafts 6 months prior to implant treatment in central upper incisor regions. Following a healing time of 6 months, abutments and single‐implant crowns were installed and followed up for 2 years. Clinical photographs and impressions were taken prior to the surgical intervention as well as after crown placement and at first and second annual checkups. The photographs and study models were analyzed with regard to papilla regeneration and changes in buccal crest volume during the study period by means of a clinical papilla index and optical scanning of study models. Results: All bone grafts healed without problems. A significant reduction of the buccal crest volume (‐50%, p <.01) was observed in the grafted area before abutment connection. However, a significant increase of tissue volume (+100%, p <.05) was noticed at the subsequent crown placement, followed by a second but slow reduction of the volume during the following 2 years of function. The interdental papillae increased significantly (p <.05) in volume during the first year, almost completely filling up the embrasure areas after 2 years. Conclusions: It may be concluded that local bone grafting seems to be a valuable protocol to create sufficient bone volume for implant placement. However, significant resorption of the graft may be present, which reduces the impact of grafting on the esthetic outcome. Instead, placement of the abutment cylinder and the crown seems to play a more important role for reestablishing the tissue volume at the implant‐supported single crowns.     

Immediate implant placement and provisionalisation in the aesthetic zone

The aim of this retrospective study was to assess the outcome of immediate single‐tooth implant placement and provisionalisation in the aesthetic zone regarding hard and soft peri‐implant tissue parameters and patient‐related outcome measures in a private practice. All consecutively treated patients with single‐tooth immediate implant placement and provisionalisation between the period 1 January 2006 and 1 April 2013 in a referral practice in Amsterdam, the Netherlands, were included in the study. Fifty‐one patients of a total of 64 could be examined at follow‐up (T_follow‐up). Radiographs were present from implant placement (T_placement), after definitive crown placement (T_definitive), and new radiographs were taken at the follow‐up appointment (T_follow‐up). Next to this, soft tissue parameters, patients’ satisfaction and professionals’ aesthetic scores were measured at T_follow‐up. Implant survival was 96·9% after a mean follow‐up period of 4 years following implant placement. At definitive crown placement, mean marginal bone‐level loss was 0·25 mm (SD 0·19). Mean marginal bone‐level loss following definitive crown placement was 0·06 mm (SD 0·10) (T_definitive to T_follow‐up) after a mean follow‐up period of 4 years. Plaque index, bleeding index and gingival index scores were low. Patients’ satisfaction was rated very high: 9·0 (SD 0·7). Professionals aesthetic score was 16·49 (SD 1·86). From this study can be concluded that immediate placement of implants followed by immediate provisionalisation resulted in a high survival rate, minimum peri‐implant bone loss, very good aesthetics and satisfied patients after a mean follow‐up period of 4 years.     

Stability of Contour Augmentation and Esthetic Outcomes of Implant‐Supported Single Crowns in the Esthetic Zone: 3‐Year Results of a Prospective Study With Early Implant Placement Postextraction

Background: Early implant placement is one of the treatment options after tooth extraction. Implant surgery is performed after a healing period of 4 to 8 weeks and combined with a simultaneous contour augmentation using the guided bone regeneration technique to rebuild stable esthetic facial hard‐ and soft‐tissue contours. Methods: In this prospective study, 20 patients were treated with an implant‐born single crown and followed for 3 years. Clinical, radiologic, and esthetic parameters were recorded to assess treatment outcomes. Results: At the 3‐year examination, all 20 implants were successfully integrated, demonstrating ankylotic stability and healthy peri‐implant soft tissues as documented by standard clinical parameters. Esthetic outcomes were assessed by the pink esthetic score (PES) and white esthetic score (WES) and confirmed pleasing results overall. WES values were slightly superior to PES values. Periapical radiographs showed minimal crestal bone loss around used bone‐level implants with a mean bone loss of 0.18 mm at 3 years. Only two implants revealed bone loss between 0.5 and 1.0 mm. One of these implants had minor mucosal recession <1.0 mm. Conclusions: This prospective study evaluates the concept of early implant placement and demonstrated successful tissue integration for all 20 implants and stable bone‐crest levels around implant–abutment interfaces according to the platform‐switching concept. The midterm 3‐year follow‐up revealed pleasing esthetic outcomes and stable facial soft tissues. The risk of mucosal recession was low, with only one patient showing minor recession of the facial mucosa. These encouraging results need to be confirmed with a 5‐year follow‐up examination.     

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.     

Peri‐implant soft tissue and bone crest alterations at fixed dental prostheses: a 3‐year prospective study

Objectives: The aim of this 3‐year prospective study involving patients receiving implant‐supported fixed dental prostheses (FDPs) was to longitudinally evaluate soft and hard tissue alterations from the time of implant placement. Material and methods: Sixteen subjects with 18 implant‐supported FDPs on 43 implants were included in the study. Peri‐implant soft and hard tissue assessments were performed at implant placement, 2, 6, 12, 24 and 36 months. Variables describing the peri‐implant soft tissue conditions and topography were assessed by clinical, photographic and study model assessments. Variables of implant position and bone topography were measured in radiographs taken at each examination interval. Multilevel regression models were formulated to identify factors of significance for proximal bone crest alterations and proximal soft tissue height. Results: During the first 6 months after the one‐stage implant placement surgery, the soft tissue margin receded about 0.6 mm at facial implant sites, while a mean increase was observed at tooth‐facing proximal sites (1.1 mm) and no change at inter‐implant sites. Loss in proximal bone crest height was more pronounced at inter‐implant than tooth–implant units at 6 months (0.6 vs. 0.1 mm). Between 6 and 36 months, no further significant soft or hard tissue changes were observed. Multilevel regression analysis revealed that the proximal bone crest level significantly influenced the proximal soft tissue height assessed from the implant/abutment level. Significant predictors for loss in proximal bone crest level over the 3 years were horizontal inter‐unit distance, type of proximal unit (tooth/implant or inter‐implant) and peri‐implant bone‐level change. Conclusions: Soft and hard tissue changes around implant‐supported FDPs took place primarily during the first 6 months after the one‐stage implant installation surgery. The pattern of tissue alterations during the follow‐up differed between tooth–implant and inter‐implant proximal sites. To cite this article:
Chang M, Wennström JL. Peri‐implant soft tissue and bone crest alterations at fixed dental prostheses: a 3‐year prospective study.
Clin. Oral Impl. Res. 21, 2010; 527–534.
doi: 10.1111/j.1600‐0501.2009.01874.x     

Influences of internal tapered abutment designs on bone stresses around a dental implant: three-dimensional finite element method with statistical evaluation

Background: The aim of this study is to determine the effects of various designs of internal tapered abutment joints on the stress induced in peri‐implant crestal bone by using the three‐dimensional finite element method and statistical analyses. Methods: Thirty‐six models with various internal tapered abutment–implant interface designs including different abutment diameters (3.0, 3.5, and 4.0 mm), connection depths (4, 6, and 8 mm), and tapers (2°, 4°, 6°, and 8°) were constructed. A force of 170 N was applied to the top surface of the abutment either vertically or 45° obliquely. The maximum von Mises bone‐stress values in the crestal bone surrounding the implant were statistically analyzed using analysis of variance. In addition, patterns of bone stress around the implant were examined. Results: The results demonstrate that a smaller abutment diameter and a longer abutment connection significantly reduced the bone stresses (P <0.0001) in vertical and oblique loading conditions. Moreover, when the tapered abutment–implant interfaced connection was more parallel, bone stresses under vertical loading were less (P = 0.0002), whereas the abutment taper did not show significant effects on bone stresses under oblique loading (P = 0.83). Bone stresses were mainly influenced by the abutment diameter, followed by the abutment connection depth and the abutment taper. Conclusion: For an internal tapered abutment design, it was suggested that a narrower and deeper abutment–implant interface produced the biomechanical advantage of reducing the stress concentration in the crestal region around an implant.     

A prospective study of Astra single tooth implants

A new design of single tooth implant (AstraTech, Mölndal Sweden) featuring a microthreaded conical neck and TiO blasttm surface was evaluated clinically and radiographically after 2 years in function. Fifteen patients (age range 16 to 48) with missing maxillary anterior teeth (6 central incisors, 8 laterals, 1 bicuspid) had 4,13 mm and 11,15 mm implants placed under local anaesthesia and left for a period of 6 months before exposure and abutment connection/crown fabrication. All patients were seen at 4 to 6 monthly intervals for hygienist maintenance. Radiographs using Rinn holders and a long cone technique were taken at the crown insertion and after 1 year (14 subjects) and 2 years (12 subjects). All implants were successfully integrated at stage 2, and no implants have been lost. The internal conical seal design of the abutment/implant interface facilitated connection and there were no cases of abutment screw loosening. No soft tissue problems were observed, and the gingival morphology/health was well maintained. One crown was recemented after 18 months in function, and 1 crown was replaced because of a fracture to the porcelain incisal edge. At crown insertion, the mean bone level was 0.46 to 0.48 mm apical to the top of the implant and there were no statistically significant changes in the bone level over the 2 years of the study. In conclusion, the single tooth Astra implants were highly successful and bone changes within the first 2 years of function were comparable with other systems reporting high long‐term success rates.     

Effect of platform switching on peri-implant bone levels: a randomized clinical trial

Objective: The concept of platform switching has been introduced to implant dentistry based on observations of reduced peri‐implant bone loss. However, randomized clinical trials are still lacking. This study aimed to test the hypothesis that platform switching has a positive impact on crestal bone‐level changes. Material and methods: Two implants with diameters of 4 mm were inserted epicrestally into one side of the posterior mandibles of 25 subjects. After 3 months of submerged healing, the reentry surgery was performed. On the randomly placed test implant, an abutment 3.3 mm in diameter was mounted, resulting in a horizontal circular step of 0.35 mm (platform switching). The control implant was straight, with an abutment 4 mm in diameter. Single‐tooth crowns were cemented provisionally. All patients were monitored at short intervals over the course of 1 year. Standardized radiographs and microbiological samples from the implants' inner spaces were obtained at baseline (implant surgery), and after 3, 4, and 12 months. Results: After 1 year, the mean radiographic vertical bone loss at the test implants was 0.53±0.35 mm and at the control implants, it was 0.58±0.55 mm. The mean intraindividual difference was 0.05±0.56 mm, which is significantly <0.35 mm (P=0.0093, post hoc power 79.9%). The crestal bone‐level changes depended on time (P<0.001), but not on platform switching (P=0.4). The implants' internal spaces were contaminated by bacteria, with no significant differences in the total counts between the test and the control at any time point (P=0.98). Conclusions: The present randomized clinical trial could not confirm the hypothesis of a reduced peri‐implant bone loss at implants restored according to the concept of platform switching. To cite this article:
Enkling N, Jöhren P, Klimberg V, Bayer S, Mericske‐Stern R, Jepsen S. Effect of platform switching on peri‐implant bone levels: a randomized clinical trial.
Clin. Oral Impl. Res. 22 , 2011; 1185–1192.
doi: 10.1111/j.1600‐0501.2010.02090.x     

锥形束CT辅助美学区种植评价唇侧骨量的应用研究

目的应用锥形束CT(CBCT)比较拔牙后即刻种植与延期种植术后1年唇侧骨量变化的差异,评价CBCT在美学区种植唇侧骨量的诊断价值。 方法选择2009年6月至2013年6月上颌前牙区完成单颗种植的患者22例,共22颗种植体,拔牙后即刻种植与延期种植各11颗。分别在种植术前1周、术后即刻与术后1年进行CBCT影像学检查,根据设计的测量位点评价唇侧骨高度与骨厚度变化,采用SPSS 13.0软件包对测量数据进行统计学分析,采用配对t检验比较所有病例术后即刻与术后1年唇侧骨高度与骨厚度的变化。 结果即刻种植术后1年唇侧牙槽嵴高度变化差异有统计学意义(t=3.316,P=0.009),延期种植差异无统计学意义(t=2.073,P=0.068);两组术后1年唇侧骨厚度在距离种植体基台连接处1 mm处(t=2.369,P=0.042)与种植体中点处(t=3.474,P=0.007)差异均有统计学意义,在距离种植体底1 mm处差异均无统计学意义(t=1.596,P=0.145)。 结论CBCT可用于美学区种植唇侧骨量的价值诊断,可以准确评价拔牙后即刻种植与延期种植术后1年唇侧骨量变化。     

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     

Immediate Placement of Dental Implants in the Esthetic Zone: A Systematic Review and Pooled Analysis

Background: Research interest on immediate placement of dental implants has shifted from implant survival toward optimal preservation of soft and hard tissues. The aim of this study is to systematically assess the condition of implant survival, peri‐implant hard and soft tissue changes, esthetic outcome, and patient satisfaction of immediately placed single‐tooth implants in the esthetic zone. Methods: MEDLINE, EMBASE, and CENTRAL databases were searched for publications up to June 2013. Studies reporting on implant survival, changes in hard and soft peri‐implant tissues, esthetic outcome, and patient satisfaction were considered. A pooled analysis was performed to identify factors associated with survival and peri‐implant tissue changes after immediate implant placement. Results: Thirty‐four studies were considered eligible. Immediate placement of single‐tooth implants in the esthetic zone was accompanied by excellent 1‐year implant survival (97.1%, 95% confidence interval [CI]: 0.958 to 0.980). Mean marginal peri‐implant bone loss was 0.81 ± 0.48 mm, mean loss of interproximal peri‐implant mucosa level was 0.38 ± 0.23 mm, and mean loss of peri‐implant midfacial mucosa level was 0.54 ± 0.39 mm. Regression analysis revealed that delayed provisionalization (odds ratio [OR] 58.03, 95% CI: 8.05 to 418.41, P <0.000), use of a flap (OR 19.87, 95% CI: 10.21 to 38.66, P <0.000), and use of a connective tissue graft (OR 4.56, 95% CI: 1.72 to 12.08, P <0.002) were associated with marginal peri‐implant bone‐level change >0.50 mm. Because of underreporting, esthetic results and patient outcome did not allow for reliable analysis. Conclusion: Immediate placement with immediate provisionalization of dental implants in the esthetic zone results in excellent short‐term treatment outcome in terms of implant survival and minimal change of peri‐implant soft and hard tissue dimensions.     

Clinical and Radiological Outcomes of Two Implants with Different Prosthetic Interfaces and Neck Configurations: Randomized,Controlled, Split‐Mouth Clinical Trial

Background: Peri‐implant bone loss seems to occur following implant placement/loading regardless of all the efforts to eliminate it. Several factors, including surgical trauma, biologic width establishment, lack of passive fit of the superstructures, implant‐abutment microgap, and occlusal overloading, may increase peri‐implant bone loss. Over the years, new interface designs were introduced and clinical studies suggest that internal conical connection and platform shifting may be advantageous for marginal bone preservation. Purpose: To compare clinical and radiological outcomes of two implant designs with different prosthetic interfaces and neck configurations in a randomized, controlled, split‐mouth clinical trial. Materials and Methods: Thirty‐four partially edentate patients randomly received at least one internal conical connection with back‐tapered collar and platform shifting design or external‐hexagon implants with flat‐to‐flat implant‐abutment interface. Primary end point was peri‐implant bone level changes at different time points, failures of implants and/or prosthesis, any complications, implant stability quotient (ISQ) values, and periodontal parameters. Results: No dropout occurred. Marginal bone changes were statistically significantly different with better results for the internal conical connection. No implants and prosthesis failures have been observed, yielding a cumulative survival rate of 100%. A high ISQ value was found for both implants, and no statistically significant difference was found for ISQ mean values between interventions at each time point (p > .05). All implants showed no bleeding on probing and a very slight amount of plaque at the 1‐year‐in‐function visit. Conclusions: Both implant designs investigated performed similarly in terms of failure rates, providing successful results up to 1 year after loading. The back‐tapered neck configuration with conical connection and built‐in platform shifting showed statistically lower marginal bone loss than straight neck configuration with flat‐to‐flat implant‐abutment interface and external‐hexagonal connection.     

Implant Abutment Cleaning by Plasma of Argon: 5‐Year Follow‐Up of a Randomized Controlled Trial

Background: Contamination of implant abutments could potentially influence the peri‐implant tissue inflammatory response. The aim of the present study is to assess the radiographic bone changes around customized, platform‐switched abutments placed according to the “one‐abutment‐one‐time” protocol, with and without plasma of argon cleaning treatment. Methods: Thirty healthy patients with thin gingival biotype (<1 mm) and history of periodontal disease received one maxillary implant each. Immediately before abutment connection, patients were randomly assigned to control group (cleaning protocol by steaming) or test group (plasma of argon treatment). Outcome measures were: 1) success rate of implants and prostheses; 2) biologic and prosthetic complications; 3) peri‐implant marginal bone loss (MBL); 4) esthetic and periodontal parameters; and 5) patient satisfaction. Results: Neither implants nor prostheses were lost in either group at the 5‐year follow‐up examination. Overall, both groups showed a slight amount of peri‐implant bone loss from baseline to 5 years. A statistically higher mean MBL was found in the control group compared with the test group at 6, 24, and 60 months after crown connection. Nevertheless, during the entire follow‐up period, intragroup comparison demonstrated statistically significant mean MBL in the control group, but not in the test group. The test group showed a higher mean gain at the soft tissue margin, but not for the papilla. All implants showed good periodontal parameters, with no significant differences between groups. Conclusion: Plasma of argon could be used to disinfect implant abutments before insertion to minimize future peri‐implant bone resorption.