Five-year prospective follow-up report of the Astra tech standard dental implant in clinical treatment

Between 1994 and 1999, 515 Astra standard implants were placed and documented prospectively in 107 patients. Of these implants, 364 were placed in original jawbone, 38 in areas augmented with local osteoplasty, and 113 in bone grafts from the iliac crest. The main indications for implantation were an atrophic edentulous alveolar crest (n = 361) and a shortened dental arch (n = 113). Single-tooth implants were excluded. In a special clinical examination, 56 patients with 258 implants were investigated. The average in situ time of the implants was 34.2 months. Failing osseointegration (n = 10), peri-implantitis (n = 10), and implant fracture (n = 1) in 15 patients resulted in the failure of 21 implants (4.1%). Three patients with 8 implants died from malignant tumor. Currently, 27 implants have been lost to follow-up, and 488 implants remain in situ (95.9%). Under analyses with different implant success criteria, the success rate decreased to 85%. Based on the results in this patient population, this implant was found to be a useful alternative to established implant systems for the indications analyzed.     

Retrospective evaluation of the success of oral rehabilitation using the Frialit-2 implant system. Part 1: Influence of topographic and surgical parameters

PURPOSE: This retrospective longitudinal study evaluated the success of implant-prosthetic rehabilitation with the Frialit-2 implant system. MATERIALS AND METHODS: The study was performed with 504 patients, from two treatment centers, who had received a total of 1,554 implants between May 1990 and May 2001. The data of these patients, who received the implants in various regions and for various indications, were analyzed with respect to clinical, topographic, and radiographic parameters. The mean observation period was 6.2 years, with a maximum of 134 months. RESULTS: A survival rate of 94.8% was found for all implants. The implant survival rate of 92.6% in the maxilla remained constant after 68 months of observation. In the mandible, the implant survival rate of 96.7% showed no changes after 76 months. Kaplan-Meier analysis identified jaw, occurrence of postoperative complications, and region as statistically significant factors influencing implant survival. Multivariate Cox regression showed that gender, occurrence of postoperative complications, and jaw were factors that increased the risk of implant loss. Statistically significant correlations were found between the incidence of implant loss and vertical bone loss adjacent to the implant at the time of second-stage surgery. CONCLUSION: Implant survival rate is influenced by implant site, gender, and occurrence of complications. On the whole, the Frialit-2 system proved successful in all areas of indication after long-term observation.     

Effect of low-power laser irradiation on bony implant sites

This study was designed to examine the effects of low-energy laser irradiation on osteocytes and bone resorption at bony implant sites. Five male baboons with a mean age of 6.5 years were used in the study. Four holes for accommodating implants were drilled in each iliac crest. Sites on the left side were irradiated with a 100 mW low-energy laser (690 nm) for 1 min (6 Joule) immediately after drilling and insertion of four sandblasted and etched (Frialit-2 Synchro) implants. Five days later, the bone was removed en bloc and was evaluated histomorphometrically. The mean osteocyte count per unit area was 109.8 cells in the irradiated group vs. 94.8 cells in the control group. As intra-individual cell counts varied substantially, osteocyte viability was used for evaluation. In the irradiated group, viable osteocytes were found in 41.7% of the lacuna vs. 34.4% in the non-irradiated group. This difference was statistically significant at P < 0.027. The total resorption area, eroded surface, was found to be 24.9% in the control group vs. 24.6% in the irradiated group. This difference was not statistically significant. This study showed that osteocyte viability was significantly higher in the samples that were subjected to laser irradiation immediately after implant site drilling and implant insertion, in comparison to control sites. This may have positive effects on the integration of implants. The bone resorption rate, in contrast, was not affected by laser irradiation.     

上颌前牙区牙槽嵴骨劈开增量同期种植术的临床研究

目的 :评价骨劈开增宽上颌前牙槽嵴 ,同期植入种植体的临床效果。方法 :15例患者 ,缺失上前牙1～4颗 ,有充足的牙槽嵴高度 (>13mm) ,但牙槽嵴骨厚度仅2～3mm ,采用骨劈开术 ,形成唇侧骨瓣。在唇侧骨瓣与腭侧骨板间植入3.4～4.5mm直径的Frialit-2种植体共25枚,骨板间隙充填Bio -Oss骨粉 ,覆盖Bio -Gide胶原膜或纯钛膜 ,无张力下缝合黏骨膜瓣。术后第10天和6个月时拍X线根尖周片观察种植体骨结合状况 ,并于术后6个月时行Ⅱ期手术 ,翻开软组织瓣 ,检查骨增量效果和种植体稳固性 ,测量牙槽嵴骨的宽度和拆除钛膜。结果 :1枚种植体术后1个月脱落 ,其余种植体稳固 ,且完全被骨质包埋 ,X线根尖周片证实种植体骨结合良好 ,牙槽嵴宽度增加达3～5mm ,平均增宽4.4mm。Ⅱ期手术时种植体成活率96 %。24枚种植体完成金属烤瓷修复 ,经2年的追踪观察,无一种植体松动或脱落。结论 :当前牙区牙槽嵴骨厚度2～3mm时 ,采用骨劈开术增宽牙槽嵴 ,使植种植体获得同期植入是一种行之有效的方法。     

108颗牙种植体修复一年后的临床及X线评价

目的评价牙种植体负重1年后的临床疗效,并分析种植体周围粘膜炎症与骨吸收的关系。方法对70例种植义齿修复患者共108颗负重1年以上的IMZ和Frialit-2种植体进行临床及X线检查。结果所有种植体均无松动及种植体周围X线透射影等种植失败症状,牙槽骨高度降低的均值为（0.63±0.78）mm;粘膜有炎症的位点占所有检测位点的32.9%。重度炎症位点的骨吸收值明显高于轻度炎症位点和健康位点（P<0.05）。大多数种植义齿修复患者的口腔卫生及牙周健康状况均较差。结论IMZ和Frialit-2种植体负重1年后的临床效果满意;种植体周围粘膜炎症是种植体骨吸收的主要原因之一;消除或控制粘膜炎症、改善口腔卫生和邻牙的牙周健康状况,是接受种植的患者迫切需要解决的问题。     

拔牙后应用Frialit-2种植体即刻种植的临床研究

目的 探讨 Frialit-2种植体拔牙后即刻种植的方法与体会。方法 对11例因外伤、牙折、龋齿拔牙者即刻种植16颗Frialit-2台阶柱状种植体,5例骨量不足者合用钛膜或人工骨,术后4～6个月更换愈合基台后行义齿修复。结果　10例患者15颗种植体成功,种植体与骨组织结合稳固,1例1颗种植体因缝合减张不够,拆线后伤口裂开,术后1月拆除行常规种植。结论 应严格掌握即刻种植的适应证,拔牙时避免损伤软硬组织,选择适合牙槽窝形状的台阶柱状种植体,轻度骨量不足可联合使用人工骨和骨再生引导膜,应无张力严密封闭创口。     

Single-tooth replacement with the Frialit-2 system: a retrospective clinical analysis of 146 implants

PURPOSE: This study was intended to provide a report of experience and results with Frialit-2 implants used for single-tooth replacement. MATERIALS AND METHODS: Over a 7-year period (1994-2000), 146 single-tooth implants (84 maxilla, 62 mandible) were placed in 112 patients (67 females, 45 males; 31.2 +/- 16.4 years). The sites included maxillary anterior teeth (n = 38) as well as the mandibular premolars and molars (n = 57). Ninety-three crowns were cemented and 53 crowns were screw mounted (22 with vertical, 31 with horizontal screws) on standard abutments. The follow-up time varied between 3 and 80 months (35.8 +/- 16.5 months). RESULTS: Two implants (1.4%) were lost, 1 during early loading and the other after 6 years. The most frequent prosthetic complication was isolated crown loosening of cemented crowns requiring recementation of 9 crowns (9.9%). Crowns with vertical screws showed no crown and/or screw loosening. Four crowns (2.8%) were replaced because of ceramic fracture. DISCUSSION: Peri-implant soft tissue condition, bone resorption, and Periotest values indicated satisfactory results. The cumulative implant survival rate during the follow-up period was 97.3%, and that of the crowns 96.4% (total cumulative survival rate 93.7%). CONCLUSIONS: With the low number of abutment screw loosenings (3.5%), the deep internal hexagonal retention compared favorably to external retention methods. The predominant use of long implants (98.4% > or = 13 mm) allowed a favorable implant/crown ratio with the potential for problem-free, long-term results.     

Bone Graft Healing in Reconstruction of Maxillary Atrophy

Purpose: Evaluate correlations between volume change for iliac crest bone grafts in maxillary reconstruction (graft volume change [GVC]) and bone mineral density (BMD), bone volume fraction (BVF), hematologic bone metabolic factors (I), and identify indicators of implant failure (II). Material and Methods: Forty‐six consecutive patients had their edentulous atrophic maxilla reconstructed with free autogenous bone grafts from anterior iliac crest. Endosteal implants were placed 6 months after graft healing. Computer tomography was performed after 3 weeks and 6 months after grafting. Bone biopsies were taken from the internal table of donor site for calculation (BVF), and blood samples were collected. Implant stability was measured at placement with resonance frequency analysis and expressed as implant stability quotient (ISQ). Implant failure was registered. Results: GVC in onlay bone graft was 37%. The BVF in iliac crest biopsies was 32%. Serum‐IGFBP3 differed with 79% of the samples over normal range. Fifteen patients had one or more implant failures prior to loading (early failures). Forty‐two patients were followed for a minimum of 3 years after implant loading and, in addition, 6/42 patients had one or more implants removed during the follow‐up (late failures). GVC correlated to decreased BMD of lumbar vertebrae L2‐L4 (Kruskal–Wallis test, p = .017). No correlation was found between GVC and hematologic factors (Pearson correlation test) or between GVC and BVF (Kruskal–Wallis test). No correlation was found between ISQ and GVC (Pearson correlation test, p = .865). The association between implant failures and the described factors were evaluated, and no significant correlations were found (unconditional logistic regression). Conclusion: Onlay bone grafts decrease 37% during initial healing period, which correlate to BMD of lumbar vertebrae L2‐L4. No other evaluated parameters could explain GVC. The evaluated factors could not explain implant failure.     

上颌垂直骨劈开法同期种植体植入的临床评估

目的：评估上颌垂直骨劈开法同期植入种植体的临床效果。方法：收集不同时段不同年龄患者40位,使用牙槽骨劈开手术同期种植体植入。6月后,制作固定义齿,并定期随访。结果：使用上颌垂直骨劈开法同期植入种植体共122枚,其中有11枚种植体于观察期间失败,结果显示,Frialit-2与Frialit-synchro存活率87.5%,Fri-alit-XiVE（TPS）与Frialit-XiVE S cellplus存活率96.0%。结论：利用垂直骨劈开法使上颌牙槽嵴扩张,行种植体同期植入,与常规有足量骨量种植相比,存活率相近。     

Clinical and biologic factors related to oral implant failure: a 2-year follow-up study

The purpose of this study is to evaluate urinary biomarkers of bone formation and resorption as predictive factors for oral implant failure, and to contribute to the knowledge of factors related to oral implant failure. A total of 93 patients between 18 and 85 years old, with an indication of oral implant, were eligible in this 2-year prospective, open, and nonrandomized study. Patients who had bone graft before implantation or presented with prosthetic difficulties (implant-to-crown ratio < 1, and/or unfavorable intermaxillary space) were excluded. All patients received either Frialit-2 (Friadent, Mannheim, Germany), cylinder, or screwed implants or IMZ Twin Plus (Friadent), cylinder implants, with FRIOS (Friadent) titanium coating. Serum osteocalcin, and urinary pyridinoline and deoxypyridinoline were measured, together with bone density at implant location. The primary endpoint (implant failure) was the implant removal (radiographic evidence of peri-implant bone loss and/or pockets). Factors related to implant failure were analyzed using multilevel logistic regression models to consider within-patient effects. Of the 93 patients included, 61% were female, and 16% were current smokers. A total of 266 oral implants were placed and analyzed, with a mean number of 3.1 implants by patient. Eleven and 15% of bone locations scored at D1 and D4, respectively, for the Misch bone density scoring. The majority of implants (72%) were placed more than 3 months after tooth extraction, using a Frialit-2 system in 73% of cases. The mean of osteocalcin was 17.3 (+/-9.4) ng/L; those of pyridinoline and deoxypyridinoline were 33.2 (+/-15.8) and 10.2 (+/-11.9) mmol per creatinine mmol, respectively. At one-year, 95.5% (95% confidence interval 92.5-97.5) of implants have not been removed. One year later, no further implant failed. In both univariate and multivariate analysis, osteocalcin, pyridinoline, and deoxypyridinoline were not significant predictive factors of oral implant failure. In multilevel logistic regression analysis, only tobacco consumption and single-tooth replacement or removable prosthesis were independent and significant predictive factors of oral implant failure. Serum osteocalcin, and urinary pyridinoline and deoxypyridinoline were not predictive of oral implant failure in this study. These results suggest that oral implants are more likely to fail for posterior single-tooth replacements and removable prostheses rather than for complete edentulous fixed bridgeworks or overdentures. Tobacco smoking has been identified as a major risk factor of oral implant failure.     

Fully vs. partially rough implants in maxillary sinus floor augmentation: a randomized-controlled clinical trial

OBJECTIVES: To compare implants with a rough surface in their whole length (FR) with implants having a 2 mm coronal machined portion (PR) when used in association with a sinus-lift procedure. MATERIAL AND METHODS: Twenty-six patients with 2 mm< or =x< or =9 mm residual alveolar crest were prosthetically restored with implants after a staged sinus-lift procedure using osteotomes. In 13 randomly chosen patients, no more than one FR implant was placed (test group), while the rest were PR implants. The other 13 patients received only PR implants (control group). For comparisons, only one implant from each patient was used, i.e., from the test group only the 13 FR implants were used, while from the control group, one PR implant was randomly chosen. The presence/absence of plaque, BOP, PPD and REC were registered at the day of delivery of the restorations and after 1 year. Residual alveolar crest height and marginal bone levels around the implants were evaluated on standardized periapical radiographs taken at various stages. RESULTS: Four FR and two PR implants were lost, and the cumulative survival rate was 82.9% (six lost out of 35). There were no significant differences between the two groups. Implant type, residual alveolar crest height, time of osseointegration, time of implant loading and smoking did not seem to influence implant survival. CONCLUSIONS: FR and PR implants placed in augmented sinuses did not differ in their clinical performance.     

Clinical and radiographic evaluation of the papilla level adjacent to single-tooth dental implants. A retrospective study in the maxillary anterior region.

BACKGROUND: The regeneration of gingival papillae after single-implant treatment is an area of current investigation. This study was designed to determine: 1) whether the distance from the base of the contact point to the crest of the bone would correlate with the presence or absence of interproximal papillae adjacent to single-tooth implants, and 2) whether the surgical technique at uncovering influences the outcome. METHODS: A clinical and radiographic retrospective evaluation of the papilla level around single dental implants and their adjacent teeth was performed in the anterior maxilla in 26 patients restored with 27 implants. Six months after insertion, 17 implants were uncovered with a standard technique, while 10 implants were uncovered with a technique designed to generate papilla-like formation around dental implants. Fifty-two papillae were available for clinical and radiographic evaluation. The presence or absence of papillae was determined, and the effects of the following variables were analyzed: the influence of the 2 surgical techniques; the vertical relation between the papilla height and the crest of bone between the implant and adjacent teeth; the vertical relation between the papilla level and the contact point between the crowns of the teeth and the implant; and the distance from the contact point to the crest of bone. RESULTS: When the measurement from the contact point to the crest of bone was 5 mm or less, the papilla was present almost 100% of the time. When the distance was > or = 6 mm, the papilla was present 50% of the time or less. The mean distance between the crest of bone and the most coronal papilla level (interproximal soft tissue height) was 3.85 mm (SD = 1.04). When comparing the conventional and modified surgical technique, the relation shifted from 3.77 mm (SD = 1.01) to 4.01 mm (SD = 1.10), respectively. CONCLUSIONS: These results clearly show the influence of the bone crest on the presence or absence of papillae between implants and adjacent teeth. The data also show a positive influence for the modified surgical technique, aimed at reconstructing papillae at the implant uncovering.     

Long-term study of dental implants placed into alveolar cleft sites.

OBJECTIVE: To evaluate the long-term prognosis of dental implants placed into cleft sites after bone grafting in a relatively large number of cases in order to clarify the usefulness of the modality. PATIENTS: Forty-seven patients with unilateral (dental, n=32) or bilateral (n=15) clefts of the alveolar process were included in this study. INTERVENTIONS: A total of 71 implants, including smooth- or rough-surface titanium, and hydroxyapatite (HA)-coated implants, were placed after bone grafting from the anterior iliac crest and/or mandible. The placed implants were 13 to 15 mm in length. MAIN OUTCOME: The follow-up period was from 21 to 120 months (average=60 months). Implant survival rates were calculated as cumulative survival. Marginal bone loss (MBL) from the implant shoulder was examined, with statistical analyses performed on the influence of simultaneous bone graft and surface characteristics. RESULTS: At the end of the clinical follow-up period, all implants except one were in situ and stable. Thus, the overall survival rate was 98.6% at the end of the first year and remained the same until the end of observation. Titanium implants with smooth surfaces had the lowest MBL with almost negligible regression slope, although some implants had relatively high MBL by the end of the first year. CONCLUSIONS: Implant therapy in the cleft site offers a reliable option for patients. Particular attention should be focused preoperatively on whether bone volume can provide primary implant stability.     

De Novo Bone Induction by Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2) in Maxillary Sinus Floor Augmentation

PURPOSE: This phase II study was designed to evaluate 2 concentrations of recombinant human bone morphogenetic protein-2 (rhBMP-2) for safety and efficacy in inducing adequate bone for endosseous dental implant in patients requiring staged maxillary sinus floor augmentation. MATERIALS AND METHODS: Patients were treated with rhBMP-2 (via an absorbable collagen sponge [ACS]), at concentrations of 0.75 mg/mL (n = 18), 1.50 mg/mL (n = 17), or with bone graft (n = 13). Bone induction was assessed by alveolar ridge height, width, and density measurements from computed tomography scans obtained before and 4 months after treatment and 6 months post-functional loading of dental implants (density only). RESULTS: Mean increases in alveolar ridge height at 4 months after treatment were similar among the groups; 11.3 mm, 9.5 mm, and 10.2 mm, respectively, in the bone graft, 0.75 mg/mL, and 1.50 mg/mL rhBMP-2/ACS treatment groups. Mean increases in alveolar ridge width (buccal to lingual) at the crest of the ridge were statistically different among the treatment groups; 4.7 mm, 2.0 mm, and 2.0 mm, respectively, in the bone graft, 0.75 mg/mL, and 1.50 mg/mL treatment groups (P 相似文献   

Oral implants in combination with bone grafts. A 3-year retrospective multicenter study using the Br?nemark implant system.

A retrospective, multicenter, Scandinavian study of bone grafting of alveolar processes of severely atrophic jaws in combination with implant insertion was conducted with 150 patients. Five different grafting techniques were assessed: local or full onlay; inlay; combination of onlay/inlay grafts; and LeFort I osteotomies. The majority of the patients were treated using a one-stage approach (n = 125) and all had autogenous bone grafts. A total of 781 Br?nemark implants were inserted, of which 624 were placed in bone grafts and alveolar bone. Twenty-five patients (17%) dropped out during the follow-up period of three years. Within the remaining patients, 77% of the inserted implants (n = 516) were still in function at the end of the follow-up period. A further ten implants were kept mucosa-covered, resulting in an overall implant survival rate of around 80%. Onlays, inlays and LeFort I osteotomies showed almost the same success rates (76-84%), whereas the onlay/inlay technique gave rise to less favourable results (60%). Most of the observed losses (n = 131) took place during healing and the first year of loading. More implants were lost when they were inserted simultaneously with the grafting (23%) than when they were placed in a second stage (10%). The latter technique was used mainly in combination with local onlay grafting (16/25). The failure percentage for implants inserted in non-grafted bone (11%) was lower than for those inserted in bone grafts and alveolar bone (25%). The surviving implants of treated and followed patients served, in 88% of the cases (n = 110), to support fixed bridges or overdentures, albeit, in some instances (n = 23), after additional implant placement. In only 15 patients was it necessary to fall back on conventional removable prostheses or fixed partial bridges.     

Onlay bone grafts from iliac crest: a retrospective analysis

This study was performed to address the outcomes of patients treated with onlay grafts from the iliac crest to augment the deficient jaw. The results of 173 consecutive patients who underwent bone grafting prior to implant surgery are presented. The grafts were taken from the anterior iliac crest to repair alveolar bone deficiencies that were too large to be corrected using intraoral bone grafts. Three months postoperatively, 869 implants were placed into 190 onlay grafts (167 grafts in the maxilla, 23 in the mandible). The follow-up ranged from 3 months to 23 years post implantation. All patients received a fixed prosthesis. Parameters examined included healing of the donor site and bone grafts, implant survival, peri-implant condition, and donor site morbidity. The overall survival rate for all implants was calculated to be 95% ± 2.7% according to Kaplan–Meier analysis. The implant survival rate compares favourably with those reported in studies using intraoral and extraoral bone.     

Prospective clinical evaluation of 835 multithreaded tapered screw-vent implants: results after two years of functional loading

Multithreaded tapered screw implants have been used for several years, but lack of clinical documentation about marginal bone stability and survival rates have raised concerns about the design among some clinicians. This study prospectively evaluated the survival rates, success rates, and marginal bone stability of multithreaded tapered screw implants. A total of 835 implants in diameters of 3.7 mm (9%), 4.7 mm (76%), and 6.0 mm (15%) were placed in 328 patients using a single-stage, delayed-loading protocol. The implants were restored with a variety of prostheses and monitored over 2 years of functional loading. Five implants failed and were removed before loading. Cumulative implant survival was 99.4% (n = 835); differences between mandibular (99.0%, n = 408) and maxillary (99.8%, n = 427) implants were not statistically significant (P > .20). Mean marginal bone resorption was 1.66 mm (+/- 0.13 mm). Six implants failed to meet the success criteria by sustaining mesial and distal bone loss below the first implant thread; however, they remained stable and continued functioning without pain or inflammation. Cumulative implant success was 98.6% (n = 835); differences between maxillary (98.6%) and mandibular (98.8%) implants were not statistically significant (P > .20). Success rates by implant diameter were 98.6% (3.7 mm), 98.4% (4.7 mm), and 100% (6 mm). After 2 years of functional loading, survival and success rates for multithreaded tapered implants placed in a nonsubmerged protocol equaled or surpassed those of single-thread, straight-walled implant historical controls.     

Immediate loading of mandibular dental implants in partially edentulous patients: a prospective randomized comparative study

While immediate loading in the edentulous mandible is a well-documented procedure, there are limited scientific data on immediate loading in the partially edentulous mandible. Two-year success rates of immediate loading and conventional delayed loading of dental implants in partially dentate mandibles were compared. Patients were randomized into three groups: group A (n = 40), immediate provisionalization with nonocclusal loading; group B (n = 40), immediate provisionalization with occlusal loading; and group C (n = 37), delayed loading with single-stage surgery. Baseline and 2-year measurements included implant stability quotient, insertion torque, and peri-implant bone crest radiography. Two hundred nine implants were immediately loaded in 80 patients. The 2-year success rates were 93.3% for group B and 100% for groups A and C. Immediate provisionalization provided success rates similar to those for delayed loading only when not loaded in occlusion.     

愈合期埋植型和非埋植型种植体周围牙槽骨吸收情况观察

目的：观察比较愈合期两段式埋植型和非埋植型种植体周围牙槽骨吸收情况是否存在差异。方法：收集种植义齿修复下颌后牙区牙体缺损患者44例共94颗,其中54颗两段式埋植型Frialit-2种植体和40颗两段式非埋植型ITI种植体,根据种植体植入术后和愈合后数字化全景X线片来进行种植体周围牙槽骨高度的测量。结果：显示愈合期两段式埋植型Frialit-2种植体和非埋植型ITI种植体周围骨吸收值不存在统计学差异（p=0．667〉0．05）。结论：在本实验条件下,愈合期埋植型和非埋植型种植体周围牙槽骨骨吸收改变与种植体的植入方式无关。     

Implant survival in mandibles of irradiated oral cancer patients

OBJECTIVE: The aim of this study was to analyze long-term implant survival in the mandible after radiotherapy and radical surgery in oral cancer patients. STUDY DESIGN: Between 1990 and 2003, 71 patients (15 females, 56 males; average age 57.8 years, range 16-84.1 years) were treated with dental implants after radiochemotherapy and ablative surgery of oral cancer. Radiation therapy was delivered in daily fractions of 2 Gy given on 25 days (total dose of 50 Gy). Oral defects were reconstructed microsurgically with jejunal, iliac crest or radial forearm grafts. Thereafter 316 dental implants were placed in the non-irradiated residual bone (84; 27%), irradiated residual bone (154; 49%) or grafted bone (78; 25%) at various intervals (mean interval 1.41 (+/- 1.01) years, range 0.34-6.35 years). RESULTS: The mean follow-up time after implant insertion was 5.42 (+/- 3.21) years (range 0.3-13.61 years). The overall 2-, 3-, 5-, and 8-year survival rates of all implants were 95%, 94%, 91% and 75%. Forty-four implants were lost in 21 patients during the observation period. Irradiation of the mandibular bone showed significantly (P = 0.0028) lower implant survival compared with non-irradiated mandibular bone. The 8-year survival rate in the non-irradiated residual bone (two loss), irradiated residual bone (29 loss) or grafted bone (13 loss) were 95%, 72% and 54%, respectively. Time of implantation after irradiation showed no statistically significant influence. Implant brand, length or diameter or the incidence of resective surgery on the mandible and gender of patients had no statistically significant influence on implant survival. CONCLUSION: Radiation therapy with 50 Gy was significantly related to shorter implant survival in mandibular bone. Survival was lowest in grafted bone. Time of implant placement had no statistically significant influence on survival under the conditions of this study. Although implant survival is lower in irradiated mandibles, implants significantly facilitate prosthodontic treatment and enhance outcome of oral rehabilitation in cancer patients.