A prospective randomized clinical study comparing implant-supported fixed prostheses and overdentures in the edentulous mandible: prosthodontic production time and costs

Purpose

This work compared implant-supported fixed prostheses and overdentures in the edentulous mandible in a randomized prospective study of treatment results, clinical working hours, laboratory working hours, and laboratory costs including materials.

Materials and Methods

Seventeen subjects agreed to participate. Three standard Brånemark implants were placed between the mental foramina in each patient. After the connection of standard abutments, subjects were randomly assigned to the fixed prosthesis group (n=11) or overdenture group (n=6). Subjects in the fixed group were provided with prostheses according to the All-in-One concept. Subjects in the overdenture group received a conventional denture retained by a Dolder bar system.

Results

One implant was lost in the fixed prosthesis group after 1 year. A new implant was placed, and the prosthesis was refitted. Mean clinical working hours were 3.1 in the fixed prosthesis group and 4.1 in the overdenture group. Mean laboratory working hours were 12.5 in the fixed prosthesis group and 7.7 in the overdenture group. Total laboratory costs, including materials, were on average about 1,700 US dollars for the fixed prosthesis and 1,350 US dollars for the overdenture.

Conclusion

A fixed implant-supported prosthesis in the edentulous mandible could be provided at about the same cost as an overdenture using the method described. Provided that the early survival results prove to be long lasting, the choice between a fixed and a removable prosthesis need not be a matter of economy.—Reprinted with permission of Quintessence Publishing.     

Restoration with implants in patients with recessive dystrophic epidermolysis bullosa and patient satisfaction with the implant-supported superstructure

PURPOSE: The use of endosseous implants in the prosthetic restoration of edentulous patients with recessive dystrophic epidermolysis bullosa (RDEB) may provide improved outcomes when compared with traditional prosthetic methods. The aim of this study was to evaluate the feasibility of placing endosseous implants in patients with RDEB and to compare the treatment outcomes of fixed and removable implant-supported restorations in the edentulous maxilla or mandible with the main emphasis on patient response. MATERIALS AND METHODS: Six patients with RDEB were treated with implants. All patients were completely edentulous in either the maxilla or mandible and had marked oral involvement, with alterations in the soft and hard tissues in all cases. Three patients were treated with fixed, screw-retained implant-supported prostheses, and 3 were treated with removable implant-supported prostheses. Six months after prosthetic restoration, patients were given a questionnaire to assess their psychologic well-being and satisfaction with the implant-supported restoration marked on a visual analog scale. RESULTS: A total of 38 dental implants (21 maxillary, 17 mandibular) were placed in 6 patients. The implant success rate was 97.9%. The average follow-up from implant placement was 5.5 years (range, 1 to 9). The fixed and removable implant-supported prostheses were associated with improvements in comfort and retention, function, esthetics and appearance, taste, speech, and self-esteem. The level of satisfaction was slightly higher in patients with a fixed prosthesis. CONCLUSION: These findings suggest that endosseous implants can be successfully placed and provide support for prostheses in patients with RDEB. Patients with fixed prostheses and overdentures were satisfied with their implant-supported prostheses in the edentulous maxilla and mandible.     

Long-term treatment costs associated with implant-supported mandibular prostheses in edentulous patients

PURPOSE: The study's aim was to report long-term costs in edentulous patients treated with mandibular implant-supported prostheses. MATERIALS AND METHODS: Ninety patients were divided into four groups based on the type of implant prosthesis (fixed or overdenture) and treatment year. Records were obtained from dental charts, and an economic analysis from the patient's perspective was conducted. Clinical time associated with various procedures was measured and applied to the four groups. Salary rates by age, occupation, and gender were used to value patients' time. Direct clinical and time costs over 10 years were converted to 2002 Canadian dollars using the Consumer Price Index and discounted at a 3% rate. A sensitivity analysis at an equal salary rate was carried out to test the robustness of the time costs. RESULTS: Initial treatment and maintenance costs over the observation period were significantly higher for fixed compared to overdenture prostheses. A significant improvement in maintenance costs for the first patient group treated with fixed prostheses was observed over the follow-up period. Longer term (15 years) treatment costs for the initial two groups were significantly higher for the fixed group. The sensitivity analysis at an equal salary rate demonstrated the same trend: Time costs were significantly higher for the fixed groups. CONCLUSION: Long-term treatment costs indicated that the mandibular overdenture was a less expensive treatment compared to the fixed implant prosthesis.     

Full-arch restoration of the jaw with fixed ceramo-metal prosthesis: late implant placement

BACKGROUND: The completely edentulous patient has few treatment options in conventional dentistry. When implants are considered, treatment plans range from a 2-implant overdenture to a completely implant-supported prosthesis. Fixed prosthesis is often the preferred selection of the edentulous patient. This study assesses the 5-year cumulative survival rate of implants placed to support full-arch fixed restoration. METHODS: During 1990 to 1995, 171 implants were placed in 22 completely edentulous jaws of 20 patients. All patients were discharged wearing immediate dentures. The implants were analyzed as to the number of implants per jaw, implant location, length, and diameter. RESULTS: The 5-year cumulative survival rate was 89.9%. The mean number of implants per jaw was 7.7 for the maxilla and 8 for the mandible. In the maxilla, the preferred implant locations were the canines, centrals, laterals, and first premolars; in the mandible, they were the canines, laterals, and first molars. The mean implant length was 14.2 mm for the mandible and 13.2 mm for the maxilla. The mean implant diameter was 3.6 mm for the maxilla and 3.8 for the mandible. CONCLUSIONS: The results of the present study indicate that fixed full-arch ceramo-metal restorations can be a predictable implant treatment modality for the edentulous patient.     

A review of clinical and technical considerations for fixed and removable implant prostheses in the edentulous mandible

PURPOSE: The aim of the present article is to review some of the technical treatment options for implant prostheses restoring the edentulous mandible, mainly based on the Br?nemark system. MATERIALS AND METHODS: Clinical and technical aspects are discussed for the three established concepts: (1) implant-supported fixed prosthesis, (2) removable implant-supported overdenture, and (3) combined implant-retained and soft tissue-supported overdenture prosthesis. RESULTS: The framework of an implant-supported fixed screw-retained prosthesis can be processed in gold, Co-Cr alloy, or titanium with casting, laser-welding, or milling techniques. To improve the stability and retention of a conventional complete denture, one to four implants are indicated, and unsplinted (single attachments) or splinted designs (bar systems) can be applied. The design of the overdenture prosthesis must be carefully planned according to the requirements to ensure adequate stability and optimal form, contour, and esthetics, and the patient's best comfort. CONCLUSION: A large variety of different treatment modalities exist for both the fixed and removable mandibular implant prosthesis. Clinical and technical aspects should be considered at the beginning of the treatment to: (1) select the optimal implant position, (2) establish an adequate number of functional units, (3) select the appropriate retainers, and (4) apply the best technique for framework processing and veneering.     

Treatment outcomes of fixed or removable implant-supported prostheses in the edentulous maxilla. Part I: patients' assessments

STATEMENT OF PROBLEM: Distinct clinical parameters determine whether fixed or removable implant-supported prostheses are indicated to restore the edentulous maxilla. However, there is a strong belief that fixed implant prostheses meet with greater patient acceptance and satisfaction, but this may differ from the patients' perceptions, their psychological responses to treatment, and their assessments of the treatment outcome. PURPOSE: This prospective clinical study compared the treatment outcomes of fixed and removable implant-supported restorations in the edentulous maxilla with the main emphasis on the patient's point of view.Material and methods: Twenty patients who requested an implant-supported superstructure to restore the edentulous maxilla were asked to complete a questionnaire measuring their satisfaction with the present situation and the psychologic impact of their oral health status with their responses marked on a Visual Analog Scale (VAS). Ten patients were treated with a fixed, screw-retained implant prosthesis (group 1), and 10 were treated with a removable, implant-supported and bar-retained overdenture (group 2). Six months after prosthetic rehabilitation, patients were again given the questionnaire to assess their psychologic well-being and satisfaction with the implant-supported restoration. RESULTS: Both prosthesis designs were associated with significant improvements in comfort and retention, function, esthetics and appearance, taste, speech, and self-esteem. No difference was found between the 2 groups with respect to how the patients assessed the implant therapy. However, the results indicated that patients in group 2 experienced greater differences between pretreatment and posttreatment scores for the parameters esthetics, taste, and speech. Treatment costs per unit were significantly higher in group 1 than in group 2. CONCLUSION: Patients in groups 1 and 2 were similarly satisfied with their implant-supported prostheses in the edentulous maxilla with regard to their well-being and the cost-utility, irrespective of whether the restoration was fixed or removable.     

A survey of the use of mandibular implant overdentures in 10 countries

PURPOSE: This preliminary international survey compared provision of implant-retained overdentures to fixed implant-supported prostheses for edentulous mandibles. MATERIALS AND METHODS: Questionnaires based on a 2001 Swedish study were sent to prosthodontists and specialist clinics in nine additional countries. RESULTS: Response rate varied from 53% to 100% in 10 national surveys and should allow careful comparison of results. The relationship between implant overdentures and fixed implant-supported prostheses in treatment of edentulous mandibles varied much; in Sweden, the proportion of overdentures was 12%, whereas it was 93% in The Netherlands. In all countries, the most common reason for choice of the overdenture was reduced cost. In all but two countries, the majority of respondents thought that patients with implant overdentures were equally or more satisfied with overdentures as those with fixed implant-supported prostheses. CONCLUSION: There were great differences among the 10 countries in choice of implant treatment of the edentulous mandible. The relative proportion of mandibular overdentures to fixed prostheses was low in Sweden and Greece and varied from one to two thirds in the other countries, except The Netherlands.     

Long-term marginal periimplant bone loss in edentulous patients

PURPOSE: The aim of this study was to examine the long-term periimplant bone loss in patients treated with implant-supported fixed prostheses in both jaws. MATERIALS AND METHODS: The participants comprised 44 edentulous patients who have been followed for a 15-year period after treatment with a fixed implant-supported prosthesis in the mandible. Thirteen of them also received an implant-supported fixed prosthesis in the maxilla, on average 4.5 years after the mandibular treatment. The periimplant bone level was measured on intraoral radiographs. RESULTS: The long-term results of the implant treatment were successful, and only 1% (3/273) of the implants were lost in the mandible and 7% (5/75) in the maxilla. All but one of the failures occurred before the connection of the prostheses. The mean marginal bone loss around the implants was small (less than 1 mm for a 10-year period after implant placement), and was of similar magnitude in both jaws. However, the individual variation was relatively great. There was no significant difference in marginal bone loss between those who had a maxillary complete denture during the entire observation period and those who had received a fixed implant-supported maxillary prosthesis. Smokers lost more periimplant bone than did the nonsmokers; the difference was significant in the mandible but small and nonsignificant in the maxilla. CONCLUSION: The long-term periimplant bone loss was small and of similar magnitude in the mandible and the maxilla in subjects who had received implant-supported fixed prostheses in both jaws. The prosthetic status in the maxilla, i.e., complete denture or fixed implant-supported prosthesis, had no significant influence on the mandibular periimplant bone loss.     

种植体支持切削杆固位无牙颌种植修复体的临床应用和加工技术研究

目的：探讨种植体支持切削杆固位覆盖义齿的临床效果及工艺特点.方法：28例无牙颌患者（男12例,女16例,年龄22-71岁）,共31个修复体,植入种植体168枚.所有病例在种植体植入4-6个月后开始种植修复,均采用切削杆固位的覆盖义齿修复.修复后追踪最长39个月,最短12个月.观察方法为临床检查和x线片检查.结果：31个修复体固位力好、稳定.23例患者对修复效果非常满意,5例满意.5例患者由于口腔卫生差导致种植体周围软组织炎,4例经过局部冲洗上药,炎症消退,1例在修复后五年发展为种植体周围炎,最终修改修复设计,改用磁性基台固位.X线片示27例患者的160枚种植体周围骨组织稳定,无骨吸收,1例8颗种植体周围骨吸收2-4 mm.28例患者中2例在修复后一年发生修复体树脂基托断裂,2例在修复后四年发生修复体树脂基托断裂,修补后重新使用,无需重做修复体.所有病例在修复后至最后一次复查未见种植体脱落.结论：应用种植体支持切削杆固位修复无牙颌的修复效果满意,种植体受力均匀,但加工工艺及设备要求较高,材料成本高,是该技术推广应用不足之处.     

Steri-Oss种植体支持固定和可摘义齿修复牙列缺失患者的临床回顾研究

目的：研究十年观察期内用Steri-Oss种植体修复牙列缺失患者种植体生存率和影响因素。方法：自1995-2006年,共有57例无牙颌患者接受种植与修复治疗,共353颗Steri-Oss种植体。其中81颗种植体（22.95%）做固定修复,272颗种植体（77.05%）做可摘义齿修复,观察性别、种植体部位和修复类型对种植体成功率的影响。结果：其中有9例病人24颗种植体脱落,种植体成功率93.20%,女性病人的种植体生存率略低,但性别没有显著的差异（P〉0.05）。累计的种植体生存率上颌骨92.64%,略低于下颌骨93.68%,但统计学上的没有显著差异（P〉0.05）。种植体支持的固定修复的十年成功率是97.5%,种植体固位的可摘义齿成功率99.02%,累计的种植体生存率在可摘与固定义齿修复之间没有显著性差异（P〉0.05）。结论：确认了种植体支持无牙颌病人修复学中长期成功率。种植体固位的可摘全口义齿治疗方式在种植体生存率上和种植体支持的固定义齿的结果是相同的。     

The implant-supported overdenture as an alternative to the complete mandibular denture

BACKGROUND: Approximately one-third of Americans older than 65 years of age are fully edentulous, requiring replacement of missing teeth. While the conventional denture may meet the needs of many patients, others require more retention, stability, function and esthetics, especially in the mandible. The implant-supported prosthesis is an alternative to the conventional removable denture. METHODS: This article describes the strengths of the implant-supported mandibular overdenture. The authors also outline the risks of this approach. They performed a review of recent literature to summarize the reported success rate of implants used to support a mandibular overdenture. RESULTS: The literature review indicates that implants placed in the anterior mandible (anterior to the foramen) have a success rate better than 95 percent. Patients have reported a high degree of satisfaction with the implant-supported overdenture. CONCLUSIONS: The literature indicates that implant-supported overdentures in the mandible provide predictable results with improved stability, retention, function and patient satisfaction compared with conventional dentures. Implants placed in the anterior mandible have a success rate equal to or greater than 95 percent. CLINICAL IMPLICATIONS: When planning treatment for patients with edentulous mandibles, clinicians should consider the implant-supported prosthesis.     

Placement of posterior mandibular and maxillary implants in patients with severe bone deficiency: a clinical report of procedure

The purpose of this investigation was to modify the method for implant placement in the posterior parts of the arches for fixed implant-supported prostheses using minimally invasive surgery. Eighty-six implants were placed posterior to the mental foramina in patients with severely resorbed mandibles, and 75 implants were placed in the posterior severely resorbed maxilla. Bone grafting from the mandible to the maxillary sinus was performed in 9 patients with severely atrophic maxillae. In all patients, optimal use of the anatomic features of the arch was achieved by tilting the implants. Patients were followed up for 12 to 123 months after prosthesis connection (mean 18 months). Three maxillary implants were lost at the time of abutment connection: 1 in the pterygoid plate, 1 close to the posterior sinus wall, and 1 placed in the palatal cortex. One implant was mobile approximately 1 year later, apparently because of an ill-fitting prosthesis. In the mandible, no implants were lost. The method described for the treatment of edentulous arches represents an alternative therapy to several others currently in use. This minimally invasive surgical procedure should be applicable in an outpatient clinic for treatment of severely resorbed posterior portions of the arches with implant-supported prostheses.     

A survey of implant-retained superstructure types in the edentulous mandible in The Netherlands

Treatment of mandibular edentulousness with endosseous permucosal implants has evolved to a common treatment option during the last decades. In The Netherlands, the relative cheap prosthetic treatment of implant-supported overdentures is considered a qualitatively adequate treatment. The aim of the study described in this article was to survey the treatment of edentulous mandibles by fixed implant-supported prostheses and implant-supported overdentures, and to register the different mesostructures used. All clinics of special dental care and all larger clinics for implant dentistry in The Netherlands received a questionnaire. The data provided showed that more than 90% of patients treated with implants because of mandibular edentulousness, were provided with an overdenture. In 85% of cases a bar-clip mesostructure was used. Cost control was the most important reason to choose an overdenture above a fixed implant-supported prosthesis.     

Neuromuscular coordination of masticatory muscles in subjects with two types of implant-supported prostheses

OBJECTIVES: To compare the electromyographic (EMG) characteristics of masticatory muscles in patients with fixed implant-supported prostheses and implant overdentures. MATERIAL AND METHODS: Nineteen subjects aged 45-79 years were examined. Fourteen were edentulous and had been successfully rehabilitated with (a) maxillary and mandibular implant-supported fixed prostheses (seven patients); (b) mandibular implant overdentures and maxillary complete dentures (seven patients). Five control subjects had natural dentition or single/partial (no more than two teeth) tooth or implant fixed dentures. Surface EMG of the masseter and temporal muscles was performed during unilateral gum chewing and during maximum teeth clenching. To reduce biological and instrumental noise, all values were standardized as percentage of a maximum clenching on cotton rolls. RESULTS: During clenching, temporal muscle symmetry was larger in control subjects and fixed implant-supported prosthesis patients than in overdenture patients (analysis of variance, P=0.005). No differences were found in masseter muscle symmetry or in muscular torque. Muscle activities (integrated areas of the EMG potentials over time) were significantly larger in control subjects than in implant-supported prosthesis patients (P=0.014). In both patient groups, a poor neuromuscular coordination during chewing, with altered muscular patterns, and a smaller left-right symmetry than in control subjects were found (P=0.05). No differences in masticatory frequency were found. CONCLUSION: Surface EMG analysis of clenching and chewing showed that fixed implant-supported prostheses and implant overdentures were functionally equivalent. Neuromuscular coordination during chewing was inferior to that found in subjects with natural dentition.     

Immediately loaded implants supporting fixed prostheses in the edentulous maxilla: a preliminary clinical and radiologic report

PURPOSE: To evaluate the survival rate of immediately loaded ITI sand-blasted, large-grit, acid-etched (SLA) solid-screw dental implants in the edentulous maxilla after 8 months of loading. MATERIALS AND METHODS: Twenty-eight patients (mean age 63 years) with edentulous maxillae each received 6 implants and 1 implant-supported fixed provisional prosthesis within 24 hours after surgery. After a mean healing time of 15 weeks, the patient received a definitive, screw-retained, implant-supported fixed prosthesis. A total of 168 implants were placed. Clinical parameters were registered after 1 month of loading with the implant-supported fixed prostheses as well as 8 months after implant placement. Radiologic examinations and assessments were made at implant placement and after 8 months. RESULTS: The mean marginal bone level at implant placement was 1.6 mm (range 0 to 5.1; SD 1.1) apical of the reference point (the implant shoulder). The mean marginal bone level at the 8-month follow-up was 3.2 mm (range 0.4 to 5.9; SD 1.1) apical of the reference point. Three implants failed during the healing period. DISCUSSION: The improved results in the present study might be a result of the positive effect of splinting the implants immediately after placement. CONCLUSION: ITI SLA solid-screw implants immediately loaded (ie, loaded within 24 hours of placement) and supporting fixed prostheses had successful survival rates after 8 months. The present results constitute a solid baseline for future follow-up studies.     

A comparison of hydroxylapatite coated implant retained fixed and removable mandibular prostheses over 4 to 6 years

In a 6-year prospective clinical study, 181 hydroxylapatite coated endosseous dental implants were placed into the anterior mandible of 48 patients. Twenty-one patients were treated with fixed prostheses and 27 patients with an overdenture. When the implants were exposed all 181 had integrated. To date, there is 100% survival of all implants and they all retain a functioning prostheses. The initial results were very promising, in both groups the interval success was over 95% in the first 4 years of the study. However, by year 6, the interval success rates had fallen to 83% for both the fixed and removable groups. This study also compares the construction and maintenance complications for the two types of restorations. The clinical time taken, after implant exposure, to construct the prostheses was similar whether the fixed (mean of 8 visits) or removable option (mean of 7 visits) was chosen. However, the removable restoration cost less than half the price of the fixed when both technical time and implant component costs were evaluated. Maintenance for both groups was higher than expected, but patients required more appointments in the removable group both in the first year and beyond. Regarding the prostheses itself, the incidence of remakes, relines and general adjustments was higher in the removable group. This study has shown that the overdenture offers an effective and initially a more economical alternative to the fixed prostheses, in the treatment of the edentulous mandible. However, long-term maintenance of such a prosthesis can be significant.     

A cost minimization analysis of implant treatment in mandibular edentulous patients

PURPOSE: This study aimed to determine if implant-supported overdentures are a long-term economically efficacious therapy for edentulous patients when compared to fixed osseointegrated prostheses. MATERIALS AND METHODS: Clinical records of 25 patients from two long-term studies (fixed and overdenture) were included in this analysis. A cost minimization analysis from the patient perspective was employed. Direct clinical and time costs incurred over the 9-year period were deflated to 1995 Canadian dollars using the Consumer Price Index. National salary rates by occupation and gender were used to value patients' time, and a sensitivity analysis was carried out to assess the robustness of the results when an equal mean salary rate across treatment groups was assumed. RESULTS: The mean total, clinical, and time costs were significantly higher (Ps .05) for the fixed restoration group (dollars CAD10,748, dollars CAD10,094, and dollars CAD654, respectively) when compared to the overdenture group (dollars CAD3,665, dollars CAD3,343, and dollars CAD322, respectively). The initial, maintenance, and clinical visit costs were also significantly higher (P < or = .05) in the fixed restoration group (dollars CAD7,567, dollars CAD2,527, dollars CAD542, respectively) than in the overdenture group (dollars CAD2,505, dollars CAD830, dollars CAD292, respectively). The sensitivity analysis demonstrated that the time cost for the fixed prosthodontic group (dollars CAD488 vs dollars CAD322) was still significantly higher (P = .002), even after an equal mean salary rate was assumed. CONCLUSION: Overdenture therapy for edentulous patients is a more cost-effective treatment compared to fixed prosthodontic treatment.     

A cost comparison of mandibular two-implant overdenture and conventional denture treatment

PURPOSE: This article compares the cost of mandibular two-implant overdenture treatment to that of conventional denture treatment in an academic teaching hospital. MATERIALS AND METHODS: Sixty edentulous patients (aged 65 to 75 years) participated in a randomized clinical trial. All patients received a new maxillary complete denture and either a mandibular conventional denture (n = 30) or an implant overdenture on two unsplinted implants (n = 30). Resource-based microcosting of direct and indirect costs (eg, expenses and time cost to patients) of all scheduled and unscheduled visits was conducted through 1 year following delivery of the prostheses. RESULTS: Mean direct costs (1999 CD dollars) for scheduled visits in the implant and conventional groups were 2,332 dollars and 814 dollars, respectively, and mean indirect costs were 1,150 dollars and 810 dollars, respectively. Differences between the two groups were significant. Twenty-six patients in each group had unscheduled visits during the study at a median direct cost for the overdentures of 85 dollars and 64 dollars for the conventional dentures. Median indirect costs for unscheduled visits were 163 dollars and 202 dollars, respectively. These differences were not significant. Mean total costs of the overdentures were 4,245 dollars and 2,316 dollars for the conventional dentures, and the between-group difference was significant. CONCLUSION: The direct cost of mandibular two-implant overdenture treatment was 2.4 times higher than that of conventional denture treatment. When indirect costs were added, the implant-to-conventional total cost ratio estimate was 1.8. These cost data can now be combined with estimates of the efficacy of the two types of prosthesis so practitioners and patients can make informed decisions about these prosthodontic treatment concepts.     

Maintenance requirements of implant-supported fixed prostheses opposed by implant-supported fixed prostheses, natural teeth, or complete dentures: a 5-year retrospective study

PURPOSE: The purpose of this study was to compare the maintenance requirements of implant-supported fixed prostheses with cantilever arms in edentulous jaws when opposed by fixed prostheses of similar design, by natural teeth, or by complete dentures. MATERIALS AND METHODS: The maintenance requirements for the 5-year follow-up period were obtained by examining the dental records of 37 people. Six were provided with fixed prostheses in both arches, 22 with a fixed prosthesis in the mandible opposed by a complete denture, and 9 with a fixed prosthesis opposed by natural teeth. Everyone was treated with Nobel Biocare implants using standard implant and prosthetic protocols. RESULTS: The denture teeth and acrylic resin were repaired on 44 occasions in the group with implants in both jaws, on 14 occasions in the group with implants opposed by natural teeth, and twice in the group in which the implants were opposed by a complete denture. The group with implants in both jaws was more likely to fracture the gold-alloy framework, which occurred on six occasions. The group with implants in both jaws was significantly different from the other two groups in relation to higher incidence of fracture of the teeth and gold-alloy framework. CONCLUSION: The maintenance requirements of implant-supported fixed prostheses with cantilever arms opposed by fixed prostheses of similar design were much greater than when opposed by natural teeth or complete dentures.     

A survey of the use of mandibular implant overdentures in 10 countries

Purpose

This preliminary international survey compared provision of implant-retained overdentures to fixed implant-supported prostheses for edentulous mandibles.

Materials and Methods

Questionnaires based on a 2001 Swedish study were sent to prosthodontists and specialist clinics in nine additional countries.

Results

Response rate varied from 53% to 100% in 10 national surveys and should allow careful comparison of results. The relationship between implant overdentures and fixed implant-supported prostheses in treatment of edentulous mandibles varied much; in Sweden, the proportion of overdentures was 12%, whereas it was 93% in the Netherlands. In all countries, the most common reason for choice of the overdenture was reduced cost. In all but two countries, the majority of respondents thought that patients with implant overdentures were equally or more satisfied with overdentures as those with fixed implant-supported prostheses.

Conclusion

There were great differences among the 10 countries in choice of implant treatment of the edentulous mandible. The relative proportion of mandibular overdentures to fixed prostheses was low in Sweden and Greece and varied from one to two thirds in the other countries, except the Netherlands.