Long-term treatment outcomes in edentulous patients with implant overdentures: the Toronto study

PURPOSE: Few long-term studies on overdentures report both implant and prosthodontic outcomes. The aim of this prospective study was to report long-term prosthodontic- and implant-related treatment outcomes of patients treated with design-specific implant-supported overdentures. MATERIALS AND METHODS: Between 1982 and 1992, 45 consecutively treated patients received a total of 47 overdentures (42 mandibular and 5 maxillary) supported by Br?nemark implants. Prospective clinical and radiographic data were collected over the observation period; this study presents the most recent treatment outcomes. RESULTS: Thirty patients (mean age 70 years) with 32 prostheses attended the final recall visit, with 67% of patients followed for 15.53 years (range 10 to 19 years). Six implants failed, and the prosthetic plan and implant cumulative survival rates were both in excess of 90%. Mean marginal bone loss around implants after the first year of loading was small (0.05 mm/year), although the individual variation was high. Linear regression analysis of bone loss indicated that gender, bicortical stabilization, bone quality, and healing time were predictors of bone loss for the first year of loading but not for the ensuing years. Prosthetic maintenance included fractured components, denture relining, and replacement of prostheses. On average, the longevity of overdenture prostheses was 12 years, and laboratory relining was necessary every 4 years. CONCLUSION: This study confirmed the long-term outcome success of patients treated with design-specific overdenture prostheses supported by Br?nemark implants. However, prosthetic maintenance was required, a fact that should be discussed with patients prior to treatment.     

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.     

Implant treatment in the edentulous maxillae: a 15-year follow-up study on 76 consecutive patients provided with fixed prostheses

Background: Few long‐term follow‐up studies are available on implant treatment based on patient level data related to time. Purpose The aim of this study was to report 15‐year patient‐based data in relation to time of follow up after treatment with fixed prostheses supported by implants in the edentulous upper jaw. Materials and Methods Seventy‐six edentulous consecutive patients, provided with 450 turned Brånemark implants, were followed up with regard to maintenance, complications, and radiographs taken during the follow‐up period. Results Forty‐four patients provided with 247 implants were lost to follow up. Patients followed up for 15 years showed as a group a trend of better implant survival than patients lost to follow up (p > .05). Altogether, 37 implants and 5 fixed prostheses failed during the follow‐up period. Most implants were lost at abutment surgery (n? 15) and another nine during the first year of function. The 15‐year implant and fixed prosthesis cumulative survival rate was 90.9 and 90.6%, respectively. Resin veneer fractures caused most problems, more frequent in the earlier stage while severe wear increased in the later stage of follow up. No implant fractures or loosening of abutment/bridge locking screws were noted. The mean marginal bone loss was 0.5 mm (SD 0.47) after 5 years, followed by only minimal average changes during the following years. No radiographic parameter showed any time‐dependent relationship. The percentage of patients presenting at least one implant with more than 2.0‐mm bone loss was 4.9% in the interval from 0 to 5 years and 4.0% between 10 and 15 years. Only 1.3% of implants showed >3.0 mm accumulated bone loss after 15 years. Conclusion Implant treatment in the edentulous upper jaw functions well in a 15‐year time perspective, but an insignificant trend of higher implant failures was observed for patients lost to follow up. Besides wear and fractures of veneers, no other parameter showed any time‐related relationship, indicating an increased risk for more complications during later stages of follow up. However, accumulation of smaller amount of bone loss during the years resulted in an increasing number of implants and patients with bone levels below the third thread, which could be speculated to increase future maintenance after 15 years.     

无牙颌患者种植修复的体会

目的：探讨无牙颌种植覆盖义齿、种植固定义齿修复的临床疗效。方法：对34例单颌、全颌无牙颌患进行了种植修复。单颌无牙颌26例中10例进行了杆卡修复,5例球帽修复,2例磁性固位体修复,9例种植固定修复。全颌无牙颌8例中3例种植固定修复,3例杆卡修复,2例球帽修复。结果：经6～60个月的临床观察,256枚种植体中,除3枚种植体形成纤维愈合(1．17％)外,其余253枚种植体均形成了良好的骨性结合(98．83％),种植义齿功能较好,收到了满意的临床效果。结论：对于无牙颁的患,通过精心的设计、精巧的外科手术及合理的种植修复类型的选择,完成的种植修复体能有效地恢复咀嚼功能,并能使种植体长期稳固于口腔内行使功能。     

Radiation protection prostheses for edentulous patients

A simplified technique for the construction of radiation protection prostheses for edentulous patients was described. A direct wax pattern is formed on a cold-curing acrylic resin base. A direct method for applying radiation shield material in the stent is incorporated in the procedure.     

Palatal lift prostheses for edentulous patients

A palatal lift prosthesis technique for edentulous patients has been described. A movable palatopharyngeal section that elevates the soft palate by the force of orthodontic wires was designed. The prosthesis with the movable palatopharyngeal section improved both speech and swallowing. This method may be useful for some edentulous patients with hypernasal speech.     

全口无牙颌应用种植固定修复后的咬合力分布研究

目的探讨全口无牙颌患者应用种植固定修复后的咬合力分布特点。方法选择15例全口无牙颌应用种植固定修复的患者作为实验组,15例具有天然牙列的实验者作为对照组,采用咬合力测定仪（FPD-705）测定口腔内的咬合力以及前牙区、双尖牙区和磨牙区的咬合力分布情况,分析咬合力重心位置的变化。结果种植组全牙列咬合力明显低于天然牙列,磨牙区咬合力也明显低于天然牙列,但是双尖牙区咬合力明显高于天然牙列,咬合力重心位置明显前移,左右牙列咬合力均衡。结论全口无牙颌应用种植固定修复后,双尖牙区承担了更多的咬合力。     

Masticatory performance in postmaxillectomy patients with edentulous maxillae fitted with obturator prostheses

PURPOSE: Oral cancer develops frequently in older populations. In Japan, the incidence of oral and pharyngeal cancer is 9,201 per year, with such tumors accounting for 1.74% of all cancers. Although obturator prostheses play an important role in the rehabilitation of postmaxillectomy patients, clinicians sometimes experience difficulty in placing obturator prostheses in edentulous maxillae, and criteria for the objective evaluation of treatment outcome have yet to be established. The present study aimed to investigate postsurgical factors influencing the masticatory performance of postmaxillectomy patients with edentulous maxillae fitted with obturator prostheses. MATERIALS AND METHODS: The extent of the hard palate defect, status of the mandibular dentition, mouth-opening distance, and maximum occlusal force were investigated, and masticatory performance was measured using a testing gummy jelly in 27 postmaxillectomy patients with edentulous maxillae fitted with obturator prostheses. The influence of these items was evaluated quantitatively, and theoretical masticatory performance for each subject was calculated using multiple-regression analysis (quantification method type 1). RESULTS: Although average masticatory performance was almost equivalent to that of healthy, independent older patients with occlusal support classified as Eichner C, considerable individual variation was noted among subjects. The order of strength of influence on masticatory performance was identified by category weight: extent of hard palate defect > status of posterior mandibular teeth > maximum occlusal force > mouth-opening distance. A relatively high correlation (R2 = 0.78, P < .01, Pearson correlation coefficient) was evident between theoretical and actual values. CONCLUSION: Masticatory performance could be predicted by evaluating postsurgical factors in patients with edentulous maxillae fitted with obturator prostheses.     

Stability of the screw joints in patients with implant-supported fixed prostheses in edentulous jaws: a 1-year follow-up study

PURPOSE: The purpose of this follow-up study was to evaluate the stability of the screw joint in edentulous patients 1 year after treatment with implant-supported fixed prostheses (Br?nemark system). MATERIALS AND METHODS: A total of 20 patients were included, 10 treated in the maxilla and 10 in the mandible. The fixed prostheses were removed approximately 1 year after insertion, and the stability of the screw joints was evaluated using a rating scale based upon the CDA quality evaluation criteria of dental care. RESULTS: All implant-supported fixed prostheses were recorded as stable before the prosthetic screws (gold screws) were unscrewed. "Unacceptable loosening" was observed in 4% of the prosthetic screws and in 29% of the abutment screws. CONCLUSION: In this study, only a few of the prosthetic screws showed unacceptable loosening after 1 year of function. The clinical relevance of the observed high occurrence of loose abutment screws could be questioned, as all fixed prostheses were initially recorded as stable.     

Oral function in patients treated with prostheses on Branemark osseointegrated implants in partially edentulous jaws: a pilot study

To study the oral function of partially edentulous patients treated with fixed prostheses on osseointegrated implants, recordings of the masticatory efficiency and occlusal perception of thickness were performed. The retrievable fixed partial prostheses were used to study the immediate impact of reduced fixed occlusal support on masticatory efficiency. The masticatory efficiency was subjectively satisfactory but objectively lower when compared to naturally complete dentate persons. Furthermore, the immediate impact of reduced fixed occlusal support was compromised masticatory efficiency, which was more pronounced when the occlusal support was removed on either side.     

Long-term evaluation of osseointegrated dental implants in the treatment of partly edentulous patients

AIM: The aim of this study was to evaluate the clinical, radiographic and microbiological status of implants after 10 years of functional load in patients treated for partial edentulism. METHOD: 15 patients, each successfully treated with 2-6 implants ad modum Br?nemark placed in free-standing fixed prostheses, were included in the study. RESULTS: Clinical evaluation revealed similar degrees of inflammation around teeth and implants. The probing pocket depth (PPD) was significantly greater around implants than around teeth. The mean marginal bone loss during 10 years of functional load was comparable to that found at the time of the 5-year follow-up. 74% of the implants remained free of marginal bone loss exceeding 1 mm. Marginal bone loss exceeding 2 mm, was found at only 5 sites. No marked differences in bacteria were present between teeth and implants. T. denticola, S. intermedia and P. micros were the commonest organisms detected around teeth and implants. The periodontal pathogens A. actinomycetemcomitans, P. gingivalis, P. intermedia, B. forsythus, and T. denticola, were found at implants with a marginal bone loss of more than 2 mm. CONCLUSION: Our study shows that the long-term results with implants in partially dentate patients are similar to those seen in edentulous patients and that no significant change occurred after 5-year follow-up over an additional period of 5 years.     

Long-term follow-up study of osseointegrated implants in the treatment of totally edentulous jaws

This study reviews the long-term outcome of prostheses and fixtures (implants) in 759 totally edentulous jaws of 700 patients. A total of 4,636 standard fixtures were placed and followed according to the osseointegration method for a maximum of 24 years by the original team at the University of G?teborg. Standardized annual clinical and radiographic examinations were conducted as far as possible. A lifetable approach was applied for statistical analysis. Sufficient numbers of fixtures and prostheses for a detailed statistical analysis were present for observation times up to 15 years. More than 95% of maxillae had continuous prosthesis stability at 5 and 10 years, and at least 92% at 15 years. The figure for mandibles was 99% at all time intervals. Calculated from the time of fixture placement, the estimated survival rates for individual fixtures in the maxilla were 84%, 89%, and 92% at 5 years; 81% and 82% at 10 years; and 78% at 15 years. In the mandible they were 91%, 98%, and 99% at 5 years; 89% and 98% at 10 years; and 86% at 15 years. (The different percentages at 5 and 10 years refer to results for different routine groups of fixtures with 5 to 10, 10 to 15, and 1 to 5 years of observation time, respectively.) The results of this study concur with multicenter and earlier results for the osseointegration method.