The International Journal of Oral & Maxillofacial Implants, 06/2007

Purpose: A large microgap at the implant-abutment interface has been reported to result in adverse effects, including screw loosening, abutment rotation, and abutment fracture. However, a standardized classification of the implant-abutment interface has not been established. The purposes of this investigation were (1) to propose a classification system based on the horizontal and vertical microgap of the implant-abutment interface and (2) to compare the implant-abutment interface in 4 groups of abutments. Materials and Methods: Forty-eight randomly selected external hexagonal implants were paired with (1) machined titanium abutments, (2) premachined palladium abutments cast-on with palladium alloy, (3) plastic burnout abutments cast with nickel chromium alloy, and (4) plastic burnout abutments cast with cobalt chromium alloy. A comparison of the horizontal and vertical microgaps at the implant-abutment interface was completed at 8 locations on each specimen to the nearest micrometer using an optical microscope with a magnification of 1503. Group means and significant differences between groups were determined by analysis of variance and Tukey multiple-comparisons post-hoc analysis. P .05 was the threshold for statistical significance. Results: There was no significant difference between groups with respect to vertical misfit. For horizontal misfit, machined titanium abutments presented significantly higher horizontal misfit compared to other groups (P .001). Premachined cast-on abutments had significantly higher horizontal misfit than cast NiCr abutments (P .001). In the proposed classification system, 23% of all sites measured at the implant-abutment interface had an ideal relationship, 34% had a horizontal discrepancy only, 4% had a vertical discrepancy only, and 39% had both vertical and horizontal discrepancies. Conclusion: The proposed implant-abutment classification system demonstrated a way to characterize and compare the microgap at the implant-abutment interface. Schlagwörter: implant-abutment interface, microgap

Purpose: This study evaluated the effect of primary stability on the osseointegration of turned and acid-etched screw implants in a rabbit model. Materials and Methods: One pair of turned and acid-etched implants (3.75 in diameter, 5.5 mm long) was placed in each tibia of 15 rabbits. In the right tibial metaphysis the implants were inserted according to a standard surgical protocol. In the left tibia, the osteotomy sites were enlarged using a sequence of drills, and 2 implants were placed with reduction of primary stability. Animals were sacrificed 9 weeks after surgery. Histomorphometric and removal torque analyses were performed to evaluate bone-implant contact and strength of osseointegration. Results: Surface texture had a significant effect on percentage of bone-implant contact (P = .001). Acid-etched implants with high primary stability showed the highest percentage of bone-implant contact (77%), followed by acid-etched implants with low primary stability (61%), turned implants with low primary stability (56%), and turned implants with high primary stability (46%). For removal torque, acid-etched implants had higher peak mean values than turned implant groups (P .001). Reduction of primary stability was not significant to either percentage of bone-implant contact (P = .645) or removal torque values (P = .214). Conclusion: Acid-etched implants had higher bone response and implant fixation than turned implants, regardless of primary stability. Schlagwörter: dental implant, osseointegration, primary stability, surface treatment

Purpose: To test whether there is a difference in success rates between immediately, early, and conventionally loaded implants. Materials and Methods: All randomized controlled clinical trials (RCTs) of root-form osseointegrated oral implants having a follow-up of 6 months to 1 year comparing the same osseointegrated root-form oral implants loaded immediately (within 1 week); early (between 1 week to 2 months); or conventionally (after 2 months) were eligible. An exhaustive search was conducted with no language restriction on January 15, 2007. Outcome measures were prosthesis failures, implant failures, and marginal bone levels measured on intraoral radiographs. Screening of eligible studies, quality assessment, and data extraction were conducted in duplicate. Authors were contacted for any missing information. Results were expressed as random effects models using weighted mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals. The statistical unit of the analysis was the patient. Results: Twenty RCTs were identified, and 11 trials including a total of 300 patients were included. Six trials compared immediate versus conventional loading, 3 early versus conventional loading, and 2 immediate versus early loading. None of the meta-analyses revealed any statistically significant differences. Conclusions: It is possible to successfully load dental implants immediately or early after their placement in selected patients, although not all clinicians may achieve optimal results. A high degree of primary implant stability (high value of insertion torque) seems to be 1 of the prerequisites for a successful immediate/early loading procedure. More well-designed RCTs are needed. Priority should be given to trials comparing immediately versus early loaded implants. These trials should be reported according to the CONSORT guidelines (www.consort-statement.org). Schlagwörter: dental implants, early loading, immediate loading, randomized controlled clinical trial, systematic review

Purpose: In reconstructive procedures harvested bone grafts are often temporarily stored in extraoral media while the recipient site is prepared. The aim of the present study was to analyze histomorphometrically osteocytes in calvarial bone grafts stored in either physiologic saline solution or platelet-poor plasma (PPP). Materials and Methods: Calvarial bone fragments were obtained from 12 rabbits and fixed immediately in formalin (control) or stored in PPP or in saline solution for 30 minutes prior to fixation. All specimens were decalcified and embedded in glycol methacrylate. A differential osteocyte count (normal osteocytes, abnormal osteocytes, and empty lacunae) was performed for the sections and submitted to analysis of variance (ANOVA) and the Fisher least-square-difference (LSD) test. P .05 was considered significant. Results: The histomorphometric analysis demonstrated statistically significant differences among the groups (control, PPP, saline) for all analyzed parameters (P .05). The median number of normal osteocytes observed was 31.8 ± 2.3 for the control group, 29.7 ± 4.2 for the PPP group, and 19.1 ± 4.6 for the saline group. The median number of abnormal osteocytes observed was 14.7 ± 3.9 for the saline group, 8.7 ± 2.3 for the PPP group, and 7.0 ± 2.3 for the control group. The median number of empty lacunae observed was 12.9 ± 4.7 for the saline group, 8.5 ± 2.4 for the PPP group, and 6.9 ± 2.3 for the control group. Conclusion: The current study has shown that PPP is a better storage medium for osteocyte preservation than physiologic saline solution. The best results were observed in the control group. (More than 50 references.) Schlagwörter: bone graft, osteocyte, platelet-poor plasma, platelet-rich plasma, rabbit

Purpose: The purpose of this study was to derive alternative implant shapes which could minimize the stress concentration at the shoulder level of the implant. Materials and Methods: A topological shape optimization technique (soft kill option), which mimics biological growth, was used in conjunction with the finite element (FE) method to optimize the shape of a dental implant under loads. Shape optimization of the implant was carried out using a 2-dimensional (2D) FE model of the mandible. Three-dimensional (3D) FE analyses were then performed to verify the reduction of peak stresses in the optimized design. Results: Some of the designs formulated using optimization resembled the shape of a natural tooth. Guided by the results of the optimization, alternative implant designs with a taper and a larger crestal radius at the shoulder were derived. Subsequent FE analyses indicated that the peak stresses of these optimized implants under both axial and oblique loads were significantly lower than those observed around a model of commercially available dental implant. Conclusion: The new implant shapes obtained using FE-based shape optimization techniques can potentially increase the success of dental implants due to the reduced stress concentration at the bone-implant interface. Schlagwörter: crestal bone loss, dental implant, finite element analysis, shape optimization

Purpose: The aim of this study was to evaluate the effect of 2 surface conditioning methods and 2 luting-gap sizes on the retention and durability of zirconia ceramic copings bonded to titanium abutments. Materials and Methods: Zirconia ceramic copings (Camlog Biotechnologies, Winsheim, Germany) with a luting-gap size of either 30 µm or 60 µm were bonded to titanium abutments (Camlog Biotechnologies) using the composite resin cement Panavia F (Kuraray, Osaka, Japan). The bonding surfaces of the zirconia ceramic copings were either (a) pretreated with airborne particle abrasion and cleaned with alcohol or (b) just cleaned with alcohol, whereas the bonding surfaces of all titanium abutments had been abraded and cleaned. After the specimens had been stressed for either 1, 30, 60, or 150 days by water and thermal cycling, retention was measured. Results: The surface conditioning method, luting-gap size, and storage time significantly (P = .001; 3-way analysis of variance [ANOVA]) influenced retention. Air abrasion increased the retention significantly. Failure modes were predominantly adhesive. Air-abraded copings bonded with 30-µm luting gap achieved significantly greater retention than those bonded with a 60-µm luting gap. Conclusion: Surface conditioning methods and the size of the luting gap have a significant influence on the retention of Camlog zirconia ceramic copings bonded to Camlog titanium abutments. Schlagwörter: abutment, air abrasion, resin bond, retention, titanium, zirconia

Purpose: The specific aims of this study were to measure the implant and abutment hexagonal dimensions, to measure the rotational misfit between implant and abutments, and to correlate the dimension of the gap present between the abutment and implant hexagons with the rotational misfit of 5 abutment-implant combinations from 2 manufacturers. Materials and Methods: Twenty new externally hexed implants (n = 10 for Nobel Biocare; n = 10 for Biomet/3i) and 50 new abutments were used (n = 10; Procera Zirconia; Procera Alumina; Esthetic Ceramic Abutment; ZiReal; and GingiHue post ZR Zero Rotation abutments). The mating surfaces of all implants and abutments were imaged with a scanning electron microscope before and after rotational misfit measurements. The distances between the corners and center of the implant and abutment hexagon were calculated by entering their x and y coordinates, measured on a measuring microscope, into Pythagoras' theorem. The dimensional difference between abutment and implant hexagons was calculated and correlated with the rotational misfit, which was recorded using a precision optical encoder. Each abutment was rotated (3 times/session) clockwise and counterclockwise until binding. Analysis of variance and Student-Newman-Keuls tests were used to compare rotational misfit among groups (a = .05). Results: With respect to rotational misfit, the abutment groups were significantly different from one another (P .001), with the exception of the Procera Zirconia and Esthetic Ceramic groups (P = .4). The mean rotational misfits in degrees were 4.13 ± 0.68 for the Procera Zirconia group, 3.92 ± 0.62 for the Procera Alumina group, 4.10 ± 0.67 for the Esthetic Ceramic group, 3.48 ± 0.40 for the ZiReal group, and 1.61 ± 0.24 for the GingiHue post ZR group. There was no correlation between the mean implant-abutment gap and rotational misfit. Conclusions: Within the limits of this study, machining inconsistencies of the hexagons were found for all implants and abutments tested. The GingiHue Post showed the smallest rotational misfit. All-ceramic abutments without a metal collar showed a greater rotational misfit than those with a metal collar. Schlagwörter: ceramic abutment, metal abutment, misfit, rotational freedom, screw

Purpose: The aim of this work was to evaluate the bone-repair process after implantation of homogenous demineralized dentin matrix (HDDM) slices in surgical defects created in the parietal bones of rabbits with alloxan-induced diabetes. Materials and Methods: Forty-eight rabbits were selected and divided into 4 groups of 12 rabbits: the control group, diabetic rabbits (D), diabetic rabbits with a PTFE barrier (D-PTFE), and diabetic rabbits with a PTFE barrier and with slices of homogenous demineralized dentin matrix (D-PTFE+HDDM). The diabetic animals received a single dose of alloxan monohydrate (90 mg/kg) intravenously on the marginal ear vein, and their blood glucose was verified daily. The rabbits were sacrificed after 15, 30, 60, and 90 days. The histologic findings show both better bone structure and significantly greater bone density, as determined by histomorphometric analysis, for the D-PTFE + HDDM group than for the other 3 groups (P .01). It was also observed that the mean bone density increased gradually from 15 to 90 days (except in the D-PTFE group). Conclusion: It was concluded that the HDDM was biocompatible with the bone repair of diabetic rabbits and that HDDM slices stimulated bone tissue formation. Facilitation of bone repair with HDDM could be useful in diabetic patients. Schlagwörter: bone repair, diabetes mellitus, homogenous demineralized dentin matrix, monohydrated alloxan

Purpose: The purpose of this study was to compare patterns of crestal bone remodeling with 2 sintered porous-surfaced dental implant designs during a 14-month functional period. Materials and Methods: Two root-form press-fit dental implants were evaluated in healed extraction sites in dog mandibles. The standard (control) design was a press-fit implant with a 2-mm machined collar; the remainder of the implant had a sintered porous surface. The test or "hybrid" design had 3 coronal machined threads instead of a machined collar; the remainder of the implant had a sintered porous surface. Results: Standardized radiographs indicated significantly less crestal bone loss (0.82 to 0.93 mm versus 1.45 to 1.5 mm) with the hybrid design and a slower approach toward an apparent steady state (12 to 14 months for the hybrid versus 7 months for the standard design). Morphometric assessment of back-scattered scanning electron micrographs confirmed that crestal bone loss was significantly less for the hybrid design on all but the lingual implant aspect. Conclusion: The addition of coronal threads to an implant relying on a sintered porous surface geometry for its long-term osseointegration reduced the extent of crestal bone loss compared to a machined collar region. Schlagwörter: coronal threaded collar, crestal bone loss, implant design, machined smooth collar

Purpose: The aim of this study was to evaluate the clinical and radiographic outcome of dental implants immediately placed and loaded into fresh extraction sockets after 18 months. Materials and Methods: Twenty-seven patients, 15 women and 12 men, received a total of 160 implants; 150 were placed immediately after extraction. The sockets in the study had fully preserved walls, and 10 were placed in healed sites. Immediately after surgical procedure, all patients received the temporary prosthetic reconstruction in occlusion. Five months postsurgery, definitive metal-ceramic restorations were cemented on abutments. Follow-up visits were performed for the assessment of clinical parameters. Intraoral digital radiographic examinations were performed 3 and 18 months after implant placement. Results: Minor swelling of the gingival mucosa was observed, but no mucositis or flap dehiscence with suppuration were found. Mean marginal bone loss 1 year 18 months after immediate loading was 0.65 ± 0.58 mm to the mesial side and 0.84 ± 0.69 mm to the distal side in the maxilla and 1.13 ± 0.51 mm mesially and 1.24 ± 0.60 mm distally in the mandible. There was no difference between splinted and nonsplinted implants with respect to marginal bone loss. Discussion and Conclusion: Within the limits of this clinical study, the results indicate that immediate loading of implants placed in immediate extraction sites can be carried out successfully. (Case Series) Schlagwörter: fresh extraction socket, immediate implants, immediate loading

Purpose: The purpose of this study was to report the long-term (8- to 10-year) results of hydroxyapatite (HA) -coated dental implants and compare them to the 5-year results as well as to long-term results of both HA and titanium dental implants reported in the literature. Materials and Methods: Patients were recruited, screened, and accepted or rejected sequentially based on specific inclusion/exclusion criteria. Implant placement was performed according to the manufacturer's instructions, followed by prosthetic reconstruction. Routine follow-up examinations were performed for a 5-year period. At 10 years all patients were contacted by mail and invited to participate in a longer-term follow-up of dental implants. All participants provided informed consent and underwent a complete history, including clinical and radiographic examination. The data obtained were statistically analyzed using life tables. Results: A total of 302 implants were placed in 90 patients whose average age was 54.3 years (SD 13.2 years). Of these, 114 implants in 40 patients were examined at 10 years, 88 in the mandible and 26 in the maxilla. The cumulative survival rate was 85.40% in the mandible and 70.59% in the maxilla. The total survival rate was 81.97%. Conclusions: The 10-year success rate of HA-coated dental implants was 82%. The success rate is higher in the mandible as compared to the maxilla. The 10-year results are inferior to the 5-year results. (Clinical Trial) Schlagwörter: coated implants, dental implants, hydroxyapatite

Purpose: The aim of the present study was to analyze the 2 molecular measures of inflammation: (1) the nitrite, an end metabolite of nitric oxide (NO) oxidation and (2) myeloperoxidase (MPO). Both are found in peri-implant sulcus fluid (PISF) of implants and gingival crevicular fluid (GCF) of natural teeth in healthy or diseased states. Materials and Methods: A total of 109 tooth or dental implant sites, either healthy/noninflamed, inflamed (Gingival Index [GI] > 0), or affected by periodontitis, were classified, and GCF/PISF samples were obtained. GCF/PISF MPO and nitrite levels were spectrophotometrically determined. For comparison of clinical parameters and PISF/GCF nitrite and MPO levels, Kruskal-Wallis analysis followed by Mann-Whitney test with Bonferroni correction was performed. Healthy/noninflamed, slightly inflamed, moderate/severely inflamed sites were also analyzed using the Kruskal-Wallis test followed by the Mann-Whitney test with Bonferroni correction. The correlation between nitrite and MPO levels and clinical inflammatory status were analyzed with Spearman's correlation coefficient. Results: Clinical parameters, including both the GCF and PISF volumes, demonstrated gradual increases with the presence of gingival/peri-implant inflammation (P .05). Despite the higher PISF than GCF volume at healthy sites (P = .001), there were no volumetric differences at inflamed sites (P = .771). PISF from inflamed sites (P = .025) and GCF from gingivitis and periodontitis sites presented higher total MPO levels (P .05) than samples from noninflamed sites. Despite the relatively stable GCF nitrite levels at healthy and diseased sites, PISF from inflamed sites had higher nitrite content than noninflamed sites (P .05). Conclusions: The present study demonstrated the volumetric similarities of PISF and GCF in terms of response to inflammation. However, some differences between the 2 biochemical measures of inflammation and their presence in PISF and GCF were also observed. PISF is likely to have a considerable diagnostic potential for reflecting the biologic changes around load-bearing endosseous dental implants. (Cohort Study) (More than 50 references.) Schlagwörter: dental implants, inflammation, myeloperoxidase, natural teeth, nitric oxide

Purpose: The aim of this study was to determine the clinical and histologic results of a porous synthetic hydroxyapatite (HA) compared with bovine-derived HA used in maxillary sinus augmentation. Materials and Methods: A total of 100 titanium implants were placed in 40 patients. Patients in need of maxillary sinus augmentation were divided into 2 groups. Group 1 received bovine-derived HA (20 patients with 50 implants), while group 2 received a porous synthetic HA (20 patients with 50 implants). After a healing period of 6 months, second-stage surgery was carried out. In 50 cases (25 from group 1 and 25 from group 2), bone cores were harvested from grafted areas and processed for histologic examination. Results: Four implants that failed to osseointegrate were removed at the second-stage surgery (2 from a patient from group 1, and 2 from a patient from group 2). All patients were followed for at least 1 year after loading. Histologically, most of the HA particles from both groups were surrounded by newly formed bone. No statistically significant differences were found with respect to percentage of newly formed bone between the 2 groups (P = .031); however, the groups did differ significantly with respect to the percentage of residual graft material observed (P = .001). Conclusion: This study demonstrates that both bovine-derived and porous synthetic HA can be used successfully as graft materials for maxillary sinus augmentation. The clinical performance of the 2 materials was similar. (Clinical Trial) Schlagwörter: anorganic bovine bone, hydroxyapatite, sinus augmentation

Purpose: The aim of this retrospective study was to evaluate implant survival rate, peri-implant conditions, and prosthodontic maintenance for implant-supported mandibular overdentures rigidly retained with a milled bar. Materials and Methods: Patients with 4 interforaminal implants (cylindric or screw-type) supporting an overdenture on a milled bar treated between 1996 and 2004 were asked to participate in a retrospective study. The cumulative implant survival rate and peri-implant conditions (marginal bone loss, pocket depth, Plaque Index, Gingival Index, Bleeding Index, and calculus presence) were evaluated and compared between cylindric and screw-type implants. The incidence and type of prosthodontic maintenance and subjective patient satisfaction rating were also evaluated. Results: Fifty-eight of 67 patients (87.3%) and 232 implants (76 cylindric, 156 screw-type) were available for follow-up examination after a mean period of 59.2 ± 26.9 months. The cumulative implant survival rate was 99%, and no differences in peri-implant soft tissue conditions were noted between the different implant types used. The cylindric implants showed more pronounced marginal bone resorption than the screw-type implants (1.9 ± 0.6 mm vs 2.2 ± 0.6 mm; P = .02) but the difference was not clinically significant. A low incidence of prosthodontic maintenance evenly distributed throughout the overall follow-up period and a high subjective satisfaction rating by the patients were noted. Conclusion: Interforaminal screw-type and cylindric implants supporting a milled bar for rigid overdenture anchorage were associated with a high survival rate and excellent peri-implant conditions. The incidence of prosthodontic maintenance was low and evenly distributed throughout the follow-up period as a result of rigid denture stabilization by the milled bar. Rigid anchorage of a mandibular overdenture with a milled bar unites the prosthodontic advantages of removable and fixed prostheses. (Clinical Trial) (More than 50 references.) Schlagwörter: edentulous mandible, implant-supported overdentures, milled bar, prosthodontic maintenance

Purpose: The purpose of this article is to evaluate the soft- and hard-tissue response to immediately placed implants. In addition, assessment was conducted of the soft tissue response to a transmucosal abutment which was narrower than the implant platform. Materials and Methods: This study was conducted to evaluate 10 consecutively placed immediately loaded implants placed in extraction sockets in maxillae without compromised bone tissue. The infection control phase of periodontal therapy was completed in the areas of hopeless teeth prior to extraction. Implants with a 6-mm-platform diameter were placed immediately into the fresh extraction sockets. A provisional 4-mm-diameter transmucosal abutment was subsequently connected, and a provisional crown was adapted and adjusted for nonfunctional immediate positioning. Three months following implant placement, definitive prosthetic rehabilitation was performed. At the time of prosthesis insertion (baseline) and every 6 months thereafter, radiographic assessments, pocket probing depth (PPD), recession, and papilla height were measured. An image analysis software application was used to compare the radiographic bone crestal bone heights at the mesial and distal aspects of the implants. Results: Nine patients with 10 sites were treated. Mean follow-up time was 22 months (range, 18 to 36 months). All 10 implants were found to be clinically osseointegrated. Software analysis of radiographic films showed a bone resorption of 0.78 ± 0.36 mm. The mean values were significantly lower (P ? .005) than a mean reference value of 1.7 mm. PPD did not exceed 3 mm in any site (average, 2.8 mm). Rather than recession, there was a mean gain in the buccal margin of 0.2 mm and a mean gain in papilla height of 0.25 mm. Conclusion: This proof-of-concept study suggests that immediate loading with platform switching can provide peri-implant hard tissue stability with soft tissue and papilla preservation. (Case Series) Schlagwörter: dental implants, immediate implants, immediate loading, platform switching, marginal bone loss

This paper reports an implant periapical lesion (IPL) with a previously unreported etiology. The presence of an osteolytic area around the apex and around the middle portion of a stable Straumann hollow-screw implant was found on periapical radiographs 3.5 years after implant placement. Case management involved curettage of the soft tissue surrounding the implant apex as well as resection of the nonosseointegrated portion of the implant. Histopathologic examination revealed a connective fibrous tissue containing a dense chronic inflammatory infiltrate with a foreign-body material. Polarized light microscopy and Fourier transform infrared microspectroscopy identified the foreign-body material as starch particles. Etiology of this IPL was thus related to a foreign-body reaction to starch particles. This exogenous contamination probably originated from starch-coated gloves during the surgical procedure. This case report suggests that IPL may successfully be treated by debridement and implant resection instead of implant removal. Peri-implant apical soft tissue should be systematically submitted for histopathologic examination. Schlagwörter: apical peri-implantitis, dental implants, granuloma, implant failure, radiolucency, starch

Computed-assisted surgery (CAS) has been designed to improve oral implant planning and positioning and to increase safety and operator comfort. This is especially important in the esthetic zone, at sites with bone deficiency, and when minimally invasive implant placement is the therapy of choice. Current available CAS systems are relatively large and expensive and require a lengthy learning period. This report presents a novel tactile imaging and registration concept that enables the operation of a newly developed computerized implant locating system. An intraoral bone-sounding device maps the surface of the jaw through the soft tissue. Bone contour data are registered over the computerized tomographic image. Guided by treatment preplanning software, a chairside robotic manipulator fabricates guiding sleeves that direct the drill and implant during the osteotomy and implant placement, respectively. The authors' clinical experience shows that tactile registration based the Implant Locating System is simple to use and provides accurate implant design and placement that requires only basic computer experience, minimal operational space, and low infrastructure investment. The system allows final adjustments at the time of operation, transforming each implant surgery into a fully monitored procedure. Schlagwörter: computer-assisted surgery, dental implants, flapless implant surgery, navigation, registration process

Piezoelectric bone surgery is based on ultrasonic vibration of a device functioning as an osteotome. This device allows precise cuts to be made in bone structures without provoking lesions of adjacent soft tissues and at the same time offering excellent visibility within the surgical field. The use of this technique in alveolar distraction osteogenesis is described. Piezoelectric surgery appears to make the cutting of the transport segment easier and safer. Schlagwörter: bone surgery, distraction osteogenesis, piezoelectric surgery

Severe bone atrophy in the mandible may result in weakening of the jaw, unstable dentures, and dysfunction of the inferior alveolar nerve. These conditions were diagnosed in a 65-year-old woman who presented with a severely resorbed mandible. The interforaminal region of the mandible was augmented with an onlay graft harvested from the iliac crest. Four dental implants stabilized the graft by anchoring it inferiorly to the residual mandibular basal bone. Implants later served as abutments for a fixed 12-unit implant-supported prosthesis. The patient was followed for 17 years, during which the mandibular prosthesis was replaced twice. Despite the initial questionable prognosis, oral rehabilitation was successful, with no detectable clinical signs of bone loss over the 17-year follow-up period. Schlagwörter: dental implants, iliac bone graft, mandibular severe resorption