Cancellous Bone Block Allografts for the Augmentation of the Anterior Atrophic Maxilla

Background: Pre‐implant augmentative surgery is a prerequisite in many cases in the anterior maxilla to achieve a stable, long‐term esthetic final result. Purpose: The aim of the present study was to evaluate the outcome of ridge augmentation with cancellous freeze‐dried block bone allografts in the anterior atrophic maxilla followed by placement of dental implants. Materials and Methods: Thirty‐one consecutive patients were included in the study. A bony deficiency of at least 3 mm horizontally and up to 3 mm vertically according to computerized tomography (CT) served as inclusion criteria. Sixty‐three implants were inserted after a healing period of 6 months. Nineteen of sixty‐three implants were immediately restored. Bone measurements were taken prior to bone augmentation, during implant placement, and at second‐stage surgery. Results: Forty‐six cancellous allogeneic bone blocks were used. The mean follow‐up was 34 ± 16 months. Mean bone gain was 5 ± 0.5 mm horizontally, and 2 ± 0.5 mm vertically. Mean buccal bone resorption was 0.5 ± 0.5 mm at implant placement, and 0.2 ± 0.2 mm at second‐stage surgery. Mean bone thickness buccal to the implant neck was 2.5 ± 0.5 mm at implant placement, and 2.3 ± 0.2 mm at second‐stage surgery. There was no evidence of vertical bone loss between implant placement and second‐stage surgery. Block and implant survival rates were 95.6 and 98%, respectively. All patients received a fixed implant‐supported prosthesis. Conclusion: Cancellous block allografts appear to hold promise for grafting the anterior atrophic maxilla.     

Early loading of endosseous implants in the augmented maxilla: a 1-year prospective study

In 10 patients, 68 endosseous implants were inserted in the augmented edentulous maxilla using a one-stage implant placement technique. Three months before implant insertion, the width and height of the alveolar crest were augmented with autologous bone grafts from the iliac crest. In all cases, the resulting bone volume was sufficient for implant insertion. According to an early loading protocol, the implant-supported overdenture was fabricated 2 months after insertion of the implants. Evaluation was performed according to a standardised protocol immediately and 1 year after fabrication of the prosthetic construction. The protocol included assessment of both clinical (bleeding score, pocket depth, implant mobility) and radiographic (marginal bone level on standardised radiographs) parameters. Three implants in two patients in the upper jaw were lost (survival rate: 95.6%). The peri-implant tissues had a healthy appearance and bone loss was minimal. Overall, the patients were very satisfied with the prosthetic construction. From this preliminary study, it is concluded that in selected cases, early loading of implants may develop into a predictable treatment modality after augmentation of the maxilla.     

Stability and marginal bone level measurements of unsplinted implants used for mandibular overdentures: a 1-year randomized prospective clinical study comparing early and conventional loading protocols

Objectives: The aim of this study was to compare the performance of two non‐splinted implants used as retention for a mandibular overdenture when applying conventional or early loading protocols. Material and methods: Twenty edentulous patients were treated with two unsplinted and non‐submerged implants (15 mm long, TiUnite RP, Brånemark System) in the anterior mandible. The patients were randomly allotted into two groups: (i) test group (Group A), in which the overdenture was connected 1 week after surgery, and (ii) control group (Group B), in which the overdenture was connected after 12 weeks of healing. Resonance frequency analyses (RFA) for implant stability measurements were performed at implant surgery and after 1, 3, 6, 9 and 12 months. Marginal bone levels were evaluated at implant surgery and after 6 and 12 months. Results: No implant from either group was lost and all implants showed less than 1 mm of marginal bone resorption during the first year. The mean implant stability quotient (ISQ) values at implant surgery were 76.2±2.8 for Group A and 75.6±4.5 for Group B. The 12‐month measurements showed 76.4±2.5 ISQ and 76.4±2.8 ISQ for Groups A and B, respectively. There were no statistically significant changes between or within the groups with time. There were no differences in marginal bone loss, which was on average 0.3 mm for both groups after 1 year. Conclusion: Although a limited number of patients were followed for 1 year only, the results of the present study indicate that early loading of two unsplinted 15 mm long implants with an overdenture does not negatively affect implant stability or marginal bone conditions when compared with implants subjected to 12 weeks of healing before loading.     

A prospective multicenter clinical study of the Osseotite implant: four-year interim report

This article reports the 4-year interim results of a multicenter study evaluating the clinical performance of the Osseotite dental implant. At 4 study centers, 485 Osseotite implants were consecutively placed in 181 patients (219 were placed in the mandible and 266 in the maxilla). A total of 355 implants were placed in posterior regions. Short implants (10 mm or less) represented 31.5% (n = 153) of all implants placed in this study. Patients were restored with 210 restorations, distributed as 123 short-span prostheses, 58 single-tooth replacements, 28 long-span prostheses, and 1 maxillary overdenture. At this 4-year interim evaluation, the mean time from implant placement to the most recent evaluation was 52.6 +/- 3.0 months, with a mean loading time of 43.3 +/- 3.8 months. Of the 485 implants placed, there have been 6 failures. All implant failures occurred prior to loading and were categorized as early implant failures. Five of the 6 failures occurred in the maxilla. Only one of the 153 short implants failed to integrate. Baseline radiographs were obtained at prosthesis connection. Radiographic analysis 1 year post-restoration showed a mean bone loss of 0.09 +/- 0.7 mm. From baseline to the end of the second year of function, an overall mean bone loss of 0.13 +/- 0.8 mm was recorded, indicating no additional bone was lost after the first year of implant function. At 4 years, the cumulative implant success rate for all implants placed in this study was 98.7%, with a 99.4% success rate in the posterior mandible and 98.4% success rate in the posterior maxilla. Results of this 4-year interim analysis indicate that this implant achieved a high success rate in posterior regions and that all failures with this implant in this patient population occurred prior to implant loading. When the clinical success of implants 10 mm or shorter was compared to that of implants greater than 10 mm in length, the shorter implants in this study performed similarly to longer implants.     

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.     

Immediate dental implant placement in calvarial bone grafts to rehabilitate the severely resorbed edentulous maxilla: A prospective pilot study

Purpose

The aim of this study was to describe the surgical technique of immediate dental implant placement in calvarial grafts for augmentation of the severely resorbed maxilla and to assess the treatment results.

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.     

Survival Rate for Implants Placed in the Posterior Maxilla With and Without Sinus Augmentation: A Comparative Cohort Study

Background: The reduced bone height and proximity of the maxillary sinus are the most common limitations for placement of dental implants in the posterior maxilla. Reconstruction of the atrophic posterior maxilla can be performed with a sinus augmentation procedure. The aim of this cohort study is to compare the survival rate of implants placed in augmented sinus to implants placed in native bone in the posterior maxilla. Methods: This study was designed as a prospective cohort study and included consecutively treated patients. Patients who required the sinus augmentation (test group) were treated according to the two‐stage technique. Patients were scheduled for follow‐up evaluation at 3, 6, and 12 months after implant placement and then every 6 months for ≤6 years. Results: One hundred and five patients with 393 implants were enrolled in the study. Two hundred and one implants were placed after preliminary sinus floor grafting in 41 patients. The control group contained 64 patients with 192 implants that were placed in pristine bone of the posterior maxilla. The cumulative implant survival rates were 86.1% and 96.4%, respectively. The difference between the two groups was highly significant (P <0.005). Conclusions: These findings show that implants placed in augmented sinuses had a lower survival rate compared to implants placed in pristine bone. All the implant failures in the augmented sinuses occurred before the prosthetic rehabilitation. Moreover, it should be considered that most of the failures were observed in few patients, thus suggesting cluster behavior.     

Management of Maxillary Cluster Implant Failures with Extra‐Maxillary Implants: A Clinical Report

Late cluster implant failures can be one of the most devasting outcomes of implant therapy for patients. It can have anatomic, functional, psychological and financial consequences for patients, and sometimes the loss of residual bone can preclude subsequent implant placement. Fortunately, management of cluster implant failures in the maxilla can be mitigated by using implant anchorage from remote sites like zygomatic and pterygoid regions. Few reports exist in the literature that have described the management of cluster implant failure using extra‐maxillary implants such as zygomatic and pterygoid implants. This case report describes the management of a female patient with bruxism who experienced late cluster implant failure in the maxilla after 9 years of function with an overdenture. Due to the loss of residual bone, subsequent implant therapy involved the use of bilateral zygomatic, pterygoid and anterior maxillary implants, which were immediately loaded and thereafter used to support a complete arch fixed implant‐supported zirconia prosthesis.     

Influence of residual alveolar bone height on osseointegration of implants in the maxilla: a pilot study

Aims/Background: For sinus floor augmentation and simultaneous implant placement, a minimum of 5 mm of residual bone height has been recommended empirically. This study was designed to test this assumption in an experimental animal trial. Material and methods: In eight mini pigs, three premolars and two molars were removed on one side of the maxilla. Three months later, the animals were assigned to four groups of two animals each. A cavity was created at the base of the alveolar process so that the residual bone height was reduced to 2, 4, 6 and 8 mm, respectively. Six implants were installed and an inlay augmentation procedure was carried out using a particulated iliac bone graft. Implants were loaded with fixed provisional restorations after a healing period of 6 months. The animals were sacrificed after 6 months of functional loading. Histologic specimens were prepared and histomorphometric analysis was performed [bone‐to‐implant contact (BIC) ratio, interthread bone area, peri‐implant bone area, crestal bone resorption (CBR)]. Results: Two implants were lost during follow‐up and fibrous encapsulation was detected in one additional implant. All failures occurred in one animal with a residual alveolar height of 2 mm. On the buccal aspect, BIC turned out to be significantly higher for 6 mm when compared with 2/4 mm (75.8 ± 26.1 vs. 58 ± 23.2/53.9 ± 22.8; P<0.05), while on the palatal aspect, BIC was significantly higher for 6/8 mm when compared with 2/4 mm (80 ± 17.8/78.9 ± 10.3 vs. 55.8 ± 26.5/55.6 ± 21.3; P<0.05). For an alveolar height of 8 mm, CBR tended to be significantly lower than for bone heights of 2/4 mm (3.8 ± 2.3 vs. 5.3 ± 2.6/5.8 ± 3.9; P<0.05). Correlation analysis revealed a significant association of BIC and interthread bone area as well as a negative association to CBR on the palatal aspect. Conclusion: The results of the present study show that the combination of maxillary inlay grafting and simultaneous implant placement does not hinder osseous integration even though the alveolar crest has been reduced to a residual height of 4 mm and below. However, according to histomorphometry, the highest predictability is gained in sites with residual bone heights of 6 and 8 mm.     

Peri-implant conditions in periodontally compromised patients following maxillary sinus augmentation. A long-term post-therapy trial

Augmentation of the maxillary sinus in the atrophied edentulous posterior maxilla is an integral part of implant prosthodontics. This study examined the clinical outcome in 50 periodontally compromised successfully treated subjects with severe maxillary atrophy following oral implantation with Bråemark. IMZ or Frialit-2 endosseous implants between 1991 and 1994. Simultaneous sinus augmentation was achieved using auto-genous bone grafts harvested from the anterior mandible. Oral implants in 37 periodontally healthy patients directly placed in the stable local maxillary bone served as controls. The oral rehabilitation included implant supported restorations or removable superstructures over a period between 3 and 5 years. The peri-implant status of implant abutments inserted in the periodontal compromised augmented maxilla resulted in values comparable to the local maxillary bone except for the GCF rates with enhanced levels of 63.9±49.9 (controls 37.9±40.7). The average peri-implant Periotest values in the augmented maxillary sinus (test group) were ?3.1 PT and +0.2 PT in the controls. The Periotest scores in the sinus area ranked between ?7.0 and +5.0 with mean PT values of ?1.5 for IMZ, ?3.2 for Bråemark and ?4.0 for Frialit-2 abutments. The functional integration of oral implants following sinus augmentation with autologous bone grafts and conventionally placed endosseous implants in the local bone was similar. The additional implant stabilization within the mandibular cortical bone grafts resulted in very low Periotest scores. In periodontally compromised subjects treated for chronic adult periodontitis with minimal maxillary bone height less than 5 mm the endosseous implantation with simultaneous sinus augmentation is recommended as an appropriate technique for long-term oral implant rehabilitation.     

Influence of residual alveolar bone height on implant stability in the maxilla: an experimental animal study

Aims/Background: Empirically, for implant placement associated with sinus floor augmentation, a minimum of five mm of residual crestal bone height has been recommended in order to achieve sufficient initial implant stability. It has been the aim of the study to test this assumption in an experimental animal trial. Material and methods: In eight mini pigs, three premolars and two molars were removed on one side of the maxilla. Three months later the animals were assigned to four groups of two animals each. A cavity was created at the base of the alveolar process so that the residual bone height was reduced to 2, 4, 6 and 8 mm, respectively. The coronal part of the alveolar crest remained unchanged. An inlay augmentation procedure was carried out using a particulated autogenous bone graft from the iliac crest, and six implants (Xive, diameter 3.8 mm, length 13 mm) were placed. Implant stability was assessed by resonance frequency analysis at the time of implant placement (T0), after 6 months of unloaded healing (T1) and after 6 months of functional loading (T2). Results: During follow‐up, two implants were lost in sites with a residual alveolar bone height of 2 mm. At the time of implant placement, resonance frequencies were 6754.4±268, 6500.3±281.5, 6890.3±255.4 and 7877.9±233.7 Hz for residual bone heights of 2, 4, 6 and 8 mm, respectively. At stage‐two surgery and after 6 months of functional loading, resonance frequencies were 6431.7±290.8, 6351.8±437.6, 6213.4±376.2 and 6826.8±458.9 Hz vs. 6171±437.4, 6047±572.4, 6156.7±272.6 and 6412.8±283.5 Hz. Statistical analysis revealed an association of residual alveolar height and implant stability at T0 and T1 only (P<0.01), while bone height was not found to influence implant survival. Conclusion: The results of the present trial demonstrate an association of alveolar bone height and implant stability at the time of implant placement and stage‐two surgery. Yet the assumption that 5 mm of residual crestal bone height is a relevant threshold for simultaneous implant placement and sinus floor augmentation is not supported from an experimental point of view.     

Single‐Tooth Implants with Different Neck Designs: A Randomized Clinical Trial Evaluating the Aesthetic Outcome

Aim: To evaluate the aesthetic outcome of single‐tooth implants in the aesthetic zone with different neck designs from a professional's and patient's perception. 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 smooth neck, a rough neck with grooves or a scalloped rough neck with grooves. Implants were installed in healed sites. One year after definitive crown placement (18 months post‐implant placement), photographs were taken and the aesthetic outcome was assessed according to two objective aesthetic indexes: pink esthetic score/white esthetic score (PES/WES) and implant crown aesthetic index (ICAI). A questionnaire was used to assess the aesthetic outcome and general satisfaction from a patient's perception. Standardized radiographs were taken to measure marginal bone level changes. Results: One implant was lost. Although there was a significant difference in marginal bone loss between the different implant neck designs (smooth neck 1.19 ± 0.82 mm, rough neck 0.90 ± 0.57 mm, scalloped neck 2.01 ± 0.77 mm), there were no differences in aesthetic outcome. According to the professional's assessments using PES/WES and ICAI, 79.3% and 62% of the cases showed acceptable crown aesthetics, and 59.8% and 56.5% of the cases showed acceptable mucosa aesthetics. Overall, patients were satisfied about the aesthetics of the mucosa (81.5%) and crown (93.3%), and general patient satisfaction was high (9.0 ± 1.0 out of a maximum of 10). According to the professional's assessment, a pre‐implant augmentation procedure was associated with less favorable aesthetics of the mucosa. Conclusion: This study shows that the aesthetics of single‐tooth implants in the maxillary aesthetic zone appears to be independent of the implant neck designs applied but dependent on the need for pre‐implant surgery.     

Osteotome sinus floor elevation and simultaneous placement of implants--a 1-year retrospective study with Astra Tech implants

Background: The bone support for implants in the posterior part of the maxilla is often poor. This condition may be treated with augmentation of the maxillary sinus floor. The most common technique used is to elevate the sinus floor by inserting a bone graft through a window opened in the lateral antral wall, although less invasive techniques with osteotomes have been used since 1994. Purpose: The aim of this study was to evaluate the clinical and radiographic outcome of implants placed in the posterior maxilla with the osteotome sinus floor elevation (OSFE) technique without grafting. Materials and Methods: The study population comprised 36 consecutive patients in whom 53 implants were inserted with the OSFE technique. The indication for sinus floor elevation was that the bone height below the maxillary sinus was considered to be 10 mm or less. Results: The mean height of the alveolar process in the intended implant sites was 6.3 ± 0.3 mm, and the mean elevation of the sinus floor was 4.4 ± 0.2 mm. At the 1‐year follow‐up, two implants had been lost, both in edentulous patients. The remaining 51 implants inserted were in function, giving a 1‐year cumulative survival rate of 96%. Implants used in single‐tooth replacements and in partially edentulous cases had a 100% survival rate. The mean marginal bone level at the time of loading of the implants was 0.1 ± 0.04 mm below the reference point. One year later, the corresponding value was 0.5 ± 0.06 mm. The mean bone loss between the two examinations was 0.4 ± 0.05 mm. Conclusions: The OSFE technique, without bone grafts, was found to produce predictable results in the treatment of 36 patients with restricted bone volume in the posterior part of the maxilla.     

Multicenter Randomized Clinical Trial: Early Loading of Implants in Maxillary Bone

Purpose: The aim of this study was to show prognostic equivalence between implant loading in the maxilla after 12 weeks versus 4 weeks. Materials and Methods: One hundred four patients, from four centers in this open‐labeled randomized multicenter prospective controlled clinical trial, were assigned to either 12 weeks or 4 weeks of unloaded healing. Two hundred sixty‐nine implants (sand blasted large‐grid, acid etched [SLA] surface, ≥4.1 mm diameter; ≥10 mm length) were inserted and evaluated during an individual 5‐year follow‐up. Primary outcome was implant success after 12 months; prognostic equivalence was characterized by a maximum difference of ±5% in implant failure rates. Results: Implant‐wise 1‐year failure rates were estimated 3.1% (5/163 implants) in the 4 weeks group versus 3.6% (4/112 implants) in the 12 weeks group (95% confidence interval [CI] for the difference ?3.2 –+4.2%); implant‐wise evaluation demonstrated statistically significant prognostic equivalence of 4 and 12 weeks loading. Patient‐wise 1‐year failure rates were estimated 6.7% (n = 4 patients) in the 4 weeks group versus 5.1% (n = 2 patients) in the 12 weeks group (95% CI for the difference ?9.6 –+6.5%). All implant failures occurred within the first 3 months of the individual observation period. Prior bone augmentation, underdimensioned drilling, bone quality, implant type, implant length, implant diameter, residual teeth, and fixing of the restoration did not reveal associations with the implant outcome: trial site, posterior jaw region, and splinting were associated with a higher failure rate. Resonance frequency analysis did not serve as a predictor of implant failures at the time of implant insertion. Conclusion: Loading of standard SLA implants in the maxilla 4 weeks versus 12 weeks after insertion resulted in statistically equivalent failure patterns within a 1‐year follow‐up period; nevertheless, the observed patient‐wise failure patterns of the interim analysis requires further understanding of patient‐individual aspects of the early loading concept.     

A Double-Blind Randomized Controlled Trial (RCT) of Titanium-13Zirconium versus Titanium Grade IV Small-Diameter Bone Level Implants in Edentulous Mandibles - Results from a 1-Year Observation Period

Background: The use of endosseous dental implants has become common practice for the rehabilitation of edentulous patients, and a two‐implant overdenture has been recommended as the standard of care. The use of small‐diameter implants may extend treatment options and reduce the necessity for bone augmentation. However, the mechanical strength of titanium is limited, so titanium alloys with greater tensile and fatigue strength may be preferable. Purpose: This randomized, controlled, double‐blind, multicenter study investigated in a split‐mouth model whether small‐diameter implants made from Titanium‐13Zirconium alloy (TiZr, Roxolid?) perform at least as well as Titanium Grade IV implants. Methods and Materials: Patients with an edentulous mandible received one TiZr and one Ti Grade IV small‐diameter bone level implant (3.3 mm, SLActive®) in the interforaminal region. The site distribution was randomized and double‐blinded. Outcome measures included change in radiological peri‐implant bone level from surgery to 12 months post‐insertion (primary), implant survival, success, soft tissue conditions, and safety (secondary). Results: Of 91 treated patients, 87 were available for the 12‐month follow‐up. Peri‐implant bone level change (?0.3 ± 0.5 mm vs ?0.3 ± 0.6 mm), plaque, and sulcus bleeding indices were not significantly different between TiZr and Ti Grade IV implants. Implant survival rates were 98.9 percent and 97.8 percent, success rates were 96.6 percent and 94.4 percent, respectively. Nineteen minor and no serious adverse events were related to the study devices. Conclusion: This study confirms that TiZr small‐diameter bone level implants provide at least the same outcomes after 12 months as Ti Grade IV bone level implants. The improved mechanical properties of TiZr implants may extend implant therapy to more challenging clinical situations.     

Extra short dental implants supporting an overdenture in the edentulous maxilla: a proof of concept

Objectives: This study investigates the outcome of short implants additionally placed with longer implants to support a maxillary overdenture. Materials and methods: Twelve patients received six implants to support a maxillary overdenture. Only one patient still had two molars in the maxilla, while the others had no remaining teeth. The status of the opposing arch was diverse. The distal implant in each quadrant was 6 mm in height (S) and the middle implants ranged between 10 and 14 mm (L). All implants were placed following a one‐stage procedure and early loaded (6 weeks). Clinical and radiological parameters were assessed 6, 12 and 24 months after loading. Results: One short implant failed 2 weeks after surgery, probably due to early mobilization by the provisional prosthesis. The mean bone loss on the rough part of the implant was 0.7 mm (S) vs. 1.3 mm (L) during the first year and 0.3 mm (S) vs. 0.2 mm (L) during the second year after loading. The mean implant stability quotient values were 67 (S) vs. 70 (L) at placement and 75 (S) vs. 78 (L) after 1 year. At the 2‐year follow‐ up, all prostheses were still stable and comfortable. Conclusion: An overdenture on six implants, of which two have a reduced length, might represent a successful treatment option. No significant difference could be found between both implant lengths at 2 years' follow‐up. However, bone loss with short implants may increase the likelihood of failure.     

Osteotome Sinus Floor Elevation without Bone Grafts – A 3‐Year Retrospective Study with Astra Tech Implants

Background: The bone support for implants in the posterior part of the maxilla is often poor. This condition may be treated with augmentation of the maxillary sinus floor. The most common technique used is to elevate the sinus floor by inserting a bone graft through a window opened in the lateral antral wall. In 1994, a less‐invasive technique using osteotomes was suggested by Summers. Purpose: The aim of this study was to evaluate the clinical and radiographic outcome of implants placed in the posterior maxilla with the osteotome sinus floor elevation (OSFE) technique without grafting. Materials and Methods: The study population comprised 36 consecutive patients in whom 53 implants were inserted with the OSFE technique. The indication for sinus floor elevation was that the bone height below the maxillary sinus was considered to be 10 mm or less. Results: The mean height of the alveolar process in the intended implant sites was 6.3 ± 0.3 mm, and the mean elevation of the sinus floor was 4.4 ± 0.2 mm. Two implants in edentulous patients were lost at the 1‐year follow‐up, and one more at the 3‐year examination. The remaining 50 implants inserted were in function, giving a 3‐year cumulative survival rate of 94%. Implants used in single‐tooth replacements and in partially edentulous cases had a 100% survival rate. The marginal bone level at the time of loading of the implants was 0.1 ± 0.04 mm below the reference point. One year later, the corresponding value was 0.5 ± 0.06 mm. The mean bone loss between the two examinations was 0.4 ± 0.05 mm. At the final examination after 3 years, the mean bone level was situated 0.6 ± 0.09 mm below the reference point, indicating a nonsignificant change between 1 year and 3 years. Conclusions: The OSFE technique, without bone grafts, was found to produce predictable results in the treatment of 36 patients with restricted bone volume in the posterior part of the maxilla.     

Treatment of patients with extreme maxillary atrophy using sinus floor augmentation and implants: preliminary results

Twenty consecutive patients with extreme maxillary atrophy underwent bilateral sinus floor augmentation, either with autogenous bone from the iliac crest or with a combination of autogenous bone and hydroxyapatite. One patient was treated using autogenous bone from the chin region. After a period of three to eight months, three to four implants were placed in each posterior maxilla. Only 10 out of 155 inserted implants were located in the anterior non-augmented maxilla. During the observation period of one to six years, four implants (one of them located in the anterior maxilla) had to be removed prior to prosthetic treatment. Another three implants were lost during the follow up period. This corresponds to a Kaplan-Meier survival probability of 95.4% after 70 months. No statistically significant difference in implant success was observed between women and men (P=0.16). All prosthetic suprastructures are still in function despite these implant losses. Mean peri-implant bone resorption was 1.34 mm with no statistically significant difference between implants placed more mesially and those placed more distally in the augmented area, though a trend could be observed (P=0.058) for a more pronounced bone resorption around implants placed in the premolar region. When a mean mesial and distal bone resorption of >2 mm was considered in the calculation of the success prognosis, the survival probability dropped to 74.7% after 70 months.     

Nasal floor elevation combined with dental implant placement

Objectives: The aim of the present study was to report on the survival of dental implants placed in conjunction with nasal floor elevation. Methods: A retrospective cohort of 32 consecutive patients from two private practices was evaluated. All patients presented with alveolar bone height deficiency in the anterior region, which was not sufficient to place a dental implant according to a computed tomography (CT) scan preformed prior to implantation. Elevation and augmentation of the nasal mucosa was performed simultaneously with dental implant placement. Data collection included demographic information, as well as records of the pre‐operative available bone height, implant dimensions, bone addition following nasal floor augmentation, and survival of the implants at last follow‐up. Results: Overall, 32 patients received 100 implants that were performed in conjunction with nasal floor elevation. The average pre‐operative available bone height according to a CT scan that was preformed prior to implantation was 9.1 ± 0.9 mm and ranged from 7.3 to 11.2 mm. Bone addition following nasal floor augmentation was 3.4 ± 0.9 mm and ranged between1.1 and 5.7 mm. The mean follow‐up time was 27.8 ± 12.4 months, and during that follow‐up period, no implant failure was recorded, resulting in 100% implant survival. Conclusion: Nasal floor elevation might serve as a predictable procedure, which allows implant placement in areas with significant atrophy together with increased implant stability due to the bicortical support.