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Two-implant-retained mandibular overdentures with magnetic attachments can provide an effective treatment modality for edentulous patients. In this study, a three-dimensional finite element analysis was used to compare the biomechanical characteristics of three different types of magnetic attachments in two-implant-retained mandibular overdentures. Flat-type, dome-type, and cushion-type of the magnetic attachments were designed to retain the overdenture. Four types of load were applied to the overdenture in each model: 100 N vertical and oblique loads on the right first molar and a 100 N vertical load on the right canine and the lower incisors. The biomechanical behaviors of peri-implant bone, abutment, and mucosa were recorded. In vertical incisors, vertical right canine, and oblique molar loading condition, the flat-type group exhibited the highest levels of maximum equivalent strain/stress in the peri-implant bone. The total deformation of mucosa and the maximum equivalent strain/stress in the oblique molar loading condition are about two times as the vertical molar loading condition. These results suggested that both cushion-type and dome-type of the magnetic attachments are better choices in two-implant-retained mandibular overdentures, and oblique loading is more harmful than vertical loading.

Purpose: To evaluate the use of implant-supported overdentures (IOD) and implant-supported fixed dental prostheses (IFDP) in patients with edentulous mandibles among international prosthodontists., Materials and Methods: A questionnaire was sent by e-mail to all clinically active prosthodontists in the International College of Prosthodontists with questions related to implant treatment of the edentulous mandible performed in 2015., Results: One hundred and sixteen prosthodontists from 33 countries responded to the questionnaire. The vast majority of the responding prosthodontists was faculty or worked in private practice, and the great majority had performed treatment with mandibular implant-supported dental prostheses; however, two thirds of the respondents reported that <20% of the implant patients in their clinic had received treatment related to edentulous mandibles. The majority reported using 2 implants (84%), while 13% used 4 for overdenture retention. There were great variations regarding retention systems used for mandibular IODs; the most common was individual Locator attachments. Cost was considered the most common reason to choose mandibular IOD, There was a wide variation of materials used for mandibular IFDPs. The most common combination included milled titanium frameworks and acrylic resin teeth., Conclusions: This survey, completed by 116 prosthodontists from 33 countries, showed that implant treatment for edentulous mandibles is common, but there was great variation among the respondents regarding amount of treatments performed, design, and materials used for the implant prostheses., (© 2017 by the American College of Prosthodontists.)

Purpose: To evaluate the longitudinal denture maintenance needs of a tooth-supported overdenture population., Materials and Methods: This prospective cohort study was composed of patients who had received tooth-supported overdentures from 1974 to 1994 in the Department of Prosthodontics, University of Iowa. There were 272 persons with 662 abutments who fulfilled the inclusion criteria. To simplify analysis and reduce the number of confounding variables, only those participants wearing complete maxillary dentures and opposing complete mandibular overdentures supported by teeth #22 and #27 were included in this analysis. The denture maintenance needs of these participants were identified and related to age, gender, length of time wearing overdentures, number of medications, and denture-wearing habits. Descriptive statistics and bivariate analyses were used for the statistical analysis (α = 0.05)., Results: Of the 91 participants (mean age = 59.5 ± 10.1 years; 63.7% male) who fulfilled the inclusion criteria at baseline, 48.4% took 1 to 3 medications daily, and 84.6% wore their dentures day and night. The percentages of participants who needed one or more of the following denture treatments were: 91.2% denture base adjustments, 76.9% laboratory processed relines, 61.5% denture remakes, 33% laboratory remount and occlusal adjustment, 22% repaired bases, and 19.8% needed denture teeth replaced. Bivariate analyses indicated that participants who were 65 years and older needed more denture adjustments than patients younger than 65 years (p = 0.0343). Participants who had worn overdentures for more than 5 years were more likely to require denture remakes (p = 0.0304). Participants who wore their dentures only during the day were less likely to require repairs (p = 0.0403). Participants who did not take any medications were significantly less likely to require denture base repairs (p = 0.0258). For the 35 participants who returned for recalls at all 4 time points, males were more likely to need denture teeth repaired or replaced (p = 0.0335) and those aged 50 to 64 were more likely to need 2 or more adjustments (p = 0.0311). No overdenture abutments were lost by the participants in this study., Conclusions: According to the results of this study, age, medication usage, denture-wearing habits, and age of the overdentures were significant factors associated with denture maintenance needs. Persons wearing overdentures need regular recalls, because they have continuing maintenance needs., (© 2018 by the American College of Prosthodontists.)

Objectives: The need for denture treatment in public health will increase as the population ages. However, the impact of dentures on nutrition, particularly overdenture treatment, remains unclear although the physical and psychological effects are known. We investigated whether treatment with a mandibular implant supported overdenture improves nutrient intake and markers of nutritional status better than a conventional complete denture in edentulous patients., Design: Systematic review and meta-analysis., Methods: Medline, EMBASE and the Cochrane Central Register of Controlled Trials were searched for eligible studies published up to April 2016. We included studies which compared the treatment effect of an overdenture to conventional denture on nutrition, in which primary outcomes included changes in intake of macronutrients and/or micronutrients and/or indicators of nutritional status. Two reviewers independently evaluated eligible studies and assessed the risk of bias. We used a fixed effects model to estimate the weighted mean difference (WMD) and 95% CI for change in body mass index (BMI), albumin and serum vitamin B12 between overdenture and conventional denture 6 months after treatment., Results: Of 108 eligible studies, 8 studies involving 901 participants were included in the narrative appraisal. Four studies reported changes in markers of nutritional status and nutrient intake after treatment with a prosthetic, regardless of type. In a meta-analysis of 322 participants aged 65 years or older from three studies, pooled analysis suggested no significant difference in change in BMI between an overdenture and conventional denture 6 months after treatment (WMD=-0.18 kg/m(2) (95% CI -0.52 to 0.16)), and no significant difference in change in albumin or vitamin B12 between the two treatments., Conclusions: The modifying effect of overdenture treatment on nutritional status might be limited. Further studies are needed to evaluate the effectiveness and efficacy of denture treatments., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Objectives: To validate a new questionnaire for evaluating the 'Oral aesthetic-related quality of life (OARQoL)' of prosthetically restored patients. 'OARQoL' assesses the impact of the self-perceived dental aesthetics on patients' well-being., Methods: The 'Quality of Life associated with Dental Aesthetic Satisfaction (QoLDAS)' index was designed. After a pilot trial, 70 patients were distributed into two groups depending on their type of prosthetic rehabilitation: Group 1 (CD; n=34): muco-supported complete dentures, and Group 2 (IO; n=36): implant-retained overdentures. Patients answered the QoLDAS and the Oral Health Impact Profile (OHIP-20sp) questionnaires, and reported their satisfaction on a visual analogue scale (VAS). Socio-demographic and prosthesis-related factors were registered. Psychometric properties of the QoLDAS were investigated. Correlations between both indices were explored using the Spearman's rank test. Descriptive and non-parametric probes were run to evaluate the effect of the study variables on the OARQoL (α=0.05)., Results: The QoLDAS-9 was reliable and valid. The factor analysis confirmed the existence of three dimensions and meaningful inter-correlations among the nine finally included items. Both scales were inversely correlated. The self-reported aesthetic and functional satisfaction and the education level significantly modulated the OARQoL as measured with the QoLDAS-9., Conclusions: The QoLDAS-9 confirmed its psychometric capacity for assessing the OARQoL of CD and IO wearers. Both groups showed comparably high OARQoL. Superior education degrees lead to lower OARQoL., Clinical Significance: The QoLDAS-9 may be recommended for anticipating the effect of prosthetic restorations on OARQoL. CD and IO are predictable treatment options for improving the aesthetic self-perception of edentulous patients., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Statement of Problem: Scientific data about the long-term survival of teeth treated with cast post and cores are scarce. Retrospective studies often use different target events for their analyses. A comparison is therefore complicated. For associated tooth-, jaw-, and patient-related factors little evidence exists as to their effect on survival., Purpose: The purpose of this study was to extend the knowledge on the survival of teeth treated with cast post and cores for observation periods of more than 10 years. A decrease or increase in survival times according to the presence or absence of associated parameters needs to be evaluated., Material and Methods: A retrospective evaluation was conducted of all cast post and cores inserted in 1 university clinic between January 1992 and June 2011. A Kaplan-Meier survival analysis was carried out by using extraction as the target event. The survival curves for different tooth types, the presence or absence of adjacent teeth, and the prosthetic restoration of the respective jaws were compared by using the log-rank test (α=.05). A Cox regression model was calculated for multivariate analyses., Results: A total of 717 cast post and cores for 343 patients were recorded. The mean survival time was 13.5 years. A statistically significant decrease in survival times was found for canines (11.9 years) and premolars (13.4 years) versus molars (14.1 years), no adjacent teeth (10.6 years) versus at least 1 adjacent tooth (13.8 years), and the restoration with removable dental prostheses (12.5 years) versus fixed dental prostheses and single crowns (13.9 years). The largest reduction in survival time was found for teeth being used as an abutment for a double crown-retained removable partial dental prosthesis (telescopic denture) (9.8 years). Tooth type and adjacent tooth status remained as significant variables within the multivariate Cox regression model., Conclusions: Cast post and cores have an acceptable long-term survival time. Because different factors may influence survival, considering these factors in treatment planning may increase the long-term success of these restorations., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Purpose: The purpose of this retrospective clinical study was to evaluate the clinical outcomes of fixed implant-supported dental prostheses (FISDPs) and removable ISDPs (RISDPs) retained by telescopic attachments, the factors influencing survival, and the type and number of maintenance treatments required during the observation period., Materials and Methods: This retrospective clinical study is based on patients who were provided with ISDPs between 2004 and 2010. Patient sex, type of prosthesis, location, opposing dentition, and the effect of continuous follow-up on the probability of a favorable outcome, as well as the number of maintenance treatments, were analyzed. A statistical analysis was performed using the Kaplan-Meier method., Results: A sample of 233 patients with 157 FISDPs and 76 RISDPs supported by a total of 567 implants was randomized and included in the analysis. The mean observation period was 15.9 ± 15.4 months (maximum, 66.0 months). During the observation period, 3.9% of prostheses (7/157 FISDPs and 2/76 RISDPs) ceased to function and 2.3% of implants (13 implants) were lost. The mean survival time was 59.7 ± 2.3 months, with a survival probability of 90.2% after 3 years. Prostheses in the mandible showed significantly higher survival rates than those in the maxilla. Maintenance treatments had to be performed at an earlier stage for patients with RISDPs than for patients with FISDPs. In patients with a conventional removable prosthesis in the opposing arch, the time until maintenance was needed was significantly shorter., Conclusion: Within the limitations of a retrospective study, it can be concluded that the FISDPs and RISDPs show equally good survival rates after 3 years in function. RISDPs showed a greater and earlier need for maintenance treatments during the first years in function.

Statement of Problem: Caries and periodontal disease are the most common cause of tooth loss in overdenture populations. Longitudinal data on attachment loss in this population have not been well reported., Purpose: The purpose of this longitudinal study was to measure periodontal attachment loss in overdenture abutments., Material and Methods: In this longitudinal overdenture study, 272 persons fulfilled all of the inclusion criteria. These persons had 662 teeth, 465 (70.2%) of which were canines. This report focused only on participants with canines who returned for 3 consecutive recalls in the 42 months of the study and included 53 persons with 116 canines. During this 42-month period, 6 teeth were extracted. Attachment loss was measured at baseline and at 6 to 18 months, 19 to 30 months, and 31 to 42 months at the mesial, distal, mid-buccal, and mid-lingual surface of each tooth, and was calculated as the combination of pocket probing depth plus height above the gingiva. Attachment loss was compared at each recall. A single examiner made all the measurements., Results: At baseline, the greatest amount of loss was at the mid-buccal surface (5.43 mm), followed by the mid-lingual (4.95 mm), distal (4.41 mm), and mesial (4.35 mm) surfaces. This pattern of attachment loss did not change over the 3 time periods, except that, at the 6 to 18-month recall, the distal measurement was less than at baseline. This decrease could be due to the wear of the abutment or loss of a restoration due to caries. Attachment loss was greater on the mandibular abutments than on the maxillary abutments and could be due to the greater amount of movement of the mandibular overdenture, especially in a buccolingual direction., Conclusion: Attachment loss varied by arch and by site in patients who wore overdentures., (Copyright © 2014.)

Objectives: The aim of this sub-analysis of two prospective studies was to assess the incidence of peri-implant mucositis and peri-implantitis in fully edentulous patients with an implant-retained mandibular overdenture during a 10-year follow-up period., Material and Methods: One hundred and fifty edentulous patients with two endosseous implants to support a mandibular overdenture were available from two prospective studies. Clinical and radiographic parameters were assessed at 5 and 10 years of functional loading. Incidence of peri-implant mucositis and peri-implantitis were calculated at implant level and patient level following the Consensus of the Seventh European Workshop on Periodontology on peri-implant diseases., Results: Incidence of peri-implant mucositis at patient level was 51.9% after 5 years of evaluation and 57.0% after 10 years. Incidence of peri-implantitis at patient level was 16.9% after 5 years of evaluation and 29.7% after 10 years., Conclusion: Peri-implant mucositis and peri-implantitis do occur in totally edentulous patients and incidence numbers are high., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The aim of this study was to determine the incidence of different Kennedy's classes of partial edentulism during 18 months period., Materials and Methods: Patients were clinically examined for various Kennedy's classes of partial edentulism in the outpatient department (OPD), prosthodontics, GPRDCH, Kurnool (Andhra Pradesh)., Results: Of the total 1,420 OPD patients, Kennedy's class III was the most frequent classification encountered (62%) and followed by Kennedy's class I (18%), class II (11%), and class IV (9%) in decreasing order., Conclusion: The patients with various Kennedy's classes of partial edentulism can be offered various treatment modalities like removable cast partial dentures, fixed partial dentures, over dentures and implant supported dentures. This study can be crucial for screening the population for incidence of tooth loss as a factor of gender and age. Clinical significance: Tooth loss appears to have an important role in the loss of esthetics and mastication. Study of incidence of various classes of partial edentulism provides clinically useful information for dental training and continuing education.

Occlusal performance is a substantial determinant of the quality of dental prosthetic restorations. In the follow-up (SHIP 1) to the Study of Health in Pomerania (SHIP), a representative population of 3300 subjects was studied in the first exploratory evaluation of the occlusion of artificial teeth in the chewing center (first molar region) of partial dentures. A digital analysis of interocclusal records of habitual intercuspation position (ICP) was performed using the Greifswald Digital Analyzing System (GEDAS), a software package that identifies contact points as transparent areas. 562 subjects (280 men aged 61.7 ± 11.9 years and 282 women aged 60.7 ± 10.7 years) had maxillary removable partial dentures (RPDs), and 619 (271 men aged 65.0 ± 11.5 years and 348 women aged 62.4 ± 10.6 years) had mandibular RPDs. Most RPDs were retained with either attachment retainers (11.7% maxilla, 11.7% mandible), cast clasps (38.4% maxilla, 40.7% mandible), telescopes with double crowns (15.7% maxilla, 19.1% mandible), or wrought wire clasps (16.4% maxilla, 8.2% mandible). Some had a combination of different retention elements. The mean number of artificial teeth was 7.8 ± 2.9 in the maxilla and 7.5 ± 3.0 in the mandible. Only the artificial teeth (first molars) in mandibular partial dentures showed differences in the frequency of occlusal contacts between groups (chi-square test). Of these, telescopic crown-retained RPDs had the highest frequency of occlusal contacts (74.4% at tooth 36 and 77.1% at tooth 46), and wrought wire-retained RPDs had the lowest (48.4% at tooth 36 and 45.2% at tooth 46). The results for RPDs with a free-end saddle were comparable and analogous; contact frequencies for those with an interdental saddle did not differ significantly. Notably, the overall frequency of occlusal contacts was greater for tooth 46 (62.9%) than for tooth 36. In conclusion, when replacing teeth in the chewing center, particularly in the mandible, telescopic crown-retained RPDs offer a distinct advantage in terms of occlusal contacts and thus provide better occlusal stability.

The aim of this study was to investigate the production of mandibular implant-supported fixed and removable prostheses among prosthodontic specialists in Sweden and to compare the results with findings in a similar study made in 2001 (17). Questionnaires regarding treatment with mandibular implant prostheses during 20011 were mailed to all specialists in prosthodontics in Sweden (n = 156, according to available data). Of the 156 questionnaires, 129 (83%) were returned and of those 114 were completed. The reported number of treatments with mandibular implant-supported prostheses varied much among the specialists. Fixed implant prostheses were more common than overdentures (means 11 and 3, median values 8 and 2, respectively). However, the range was large for both alternatives. Ten (9%) of the specialists reported no treatment with fixed implant prostheses while 29 (25%) had not made any implant overdenture during 2011. The most common anchorage system for overdentures in 2011 (as well as in 2001) was two un-splinted implants with ball attachments or Locator abutments. The most common reasons for choosing overdenture treatment instead of a fixed implant prosthesis in 2011 were the reduced cost and the patient's main wish to improve denture retention. A majority of the prosthodontists (58%) reported that patients with implant overdentures were as satisfied as those with fixed implant-supported prostheses, whereas 40% claimed they were less satisfied. Two respondents (2%) considered that overdenture patients were more satisfied than those with a fixed prosthesis. It can be concluded that the general attitude among Swedish prosthodontists towards implant overdentures has not changed much during the 10-year period between the present and the previous investigation.An overdenture is still a seldom-used option in implant treatment of patients with edentulous mandibles in Sweden. Instead, a fixed implant-supported prosthesis continues to be the preferred option,

Introduction: This retrospective study evaluated the survival of endodontically treated teeth (ETTs) and investigated factors influencing restoration and tooth survival., Methods: Data from 795 ETTs were recorded, and success (restoration still intact) and survival (restoration intact or failed/repaired/replaced and tooth still in situ) were analyzed using Kaplan-Meier statistics. A multivariate Cox regression analysis was performed to assess the variables influencing success and survival., Results: At the end of the observation period (mean observation time = 4.48 years), 45 teeth had been extracted (annual failure rate for survival = 1.9% at 9.6 years) and 114 restorations had received a restorative follow-up treatment (annual failure rate for success = 4.9% at 9.6 years)., Conclusions: ETTs showed acceptable survival and success in the long-term. Variables showing significant influence on survival were the number of teeth in the dentition and the presence of decay at the moment the patient entered the practice., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: This study aimed to evaluate in a Belgian population the frequence of mucositis and peri-implantitis in patients with implants of at least 5 years of function. Another outcome was to access implants/patients characteristics as possible risk indicators for peri-implantitis., Material and Methods: One hundred and three patients (38 males/65 females) with a total of 266 implants were examined. Implants had been inserted in university hospitals as well as in private clinics and the mean time of implants in function was 8.5 years (±3.2). The average patients' age within the population was 62 years (±13.4). General health informations were recorded as well as habits regarding smoking, maintenance visits and oral hygiene. Full mouth clinical parameters (PlI, BoP, PPD) were assessed and radiographs taken to determine the periodontal status and implants diagnosis., Results: Prevalences of mucositis and peri-implantitis at the patient's level were respectively 31% and 37%. They were 38% and 23% at the implant's level. Subjects older than 65 years (OR = 1.39) and those with active periodontitis (OR = 1.98) were prone to peri-implantitis. The association was stronger for hepatitis (OR = 2.92) and totally edentulous patients (OR = 5.56). Finally, at the implant's level, a significant correlation was found in the multi-level analyses between rough surfaces, overdentures and peri-implantitis., Conclusion: After 8.5 years an important proportion (±60%) of implants presented biological complications. Furthermore, a positive correlation was showed between age, periodontitis, absence of teeth, rough surfaces and peri-implantitis. Consequently, patients with such characteristics should be informed before implant placement and frequently re-called after for maintenance visits., (© 2012 John Wiley & Sons A/S.)

Purpose: The present study provides an inventory of the number of fractures that occurred in conjunction with implant placement in edentulous patients in the Dutch population from 1980 to 2007 and estimates the incidence with which this might occur. The study also sought to define the factors that increase the risk of fracture., Materials and Methods: Questionnaires were sent to all 198 oral and maxillofacial surgeons working in 56 hospitals in the Netherlands. Questions were asked regarding the causes of fractures, the height of the edentulous mandible, and the methods of fracture treatment., Results: Responses were received from 53 of the 56 departments. During the study period, 157 edentulous mandibles fractured in conjunction with implant treatment. All fractures occurred in mandibles with less than 10 mm of height, as measured in the symphysis. An incidence of less than 0.05% was estimated based on an estimated number of 475,000 patients treated with at least two implants during this time to support an overdenture. Reasons for early implant failures were insufficient bone volume, iatrogenic causes, nonintegration, and a narrow arch. Peri-implantitis, trauma, and explantation were associated with fractures occurring 1 year or more after implant placement. Several methods were employed to treat the fractured mandibles, including closed reduction, rigid fixation using osteosynthesis plates, and bone grafts with fixation. In 52% of patients, fracture healing was uneventful; however, in 48% of patients, complications were encountered, including osteomyelitis, nonunion, plate fracture, screw loosening, and dehiscences with subsequent infections., Conclusions: Mandibles with a height of 10 mm or less, as measured at the symphysis, are at risk of fractures and associated complications. The provision of proper informed consent regarding the advantages and disadvantages of placing implants in thin mandibles is essential.

Objective: While most previous epidemiological studies have focused on subject-level risk factors for periodontal destruction, tooth-related factors have not been fully explored. The purpose of this study was to evaluate both tooth-related and subject-related factors affecting periodontal disease progression using a two-level multilevel model., Material and Methods: A longitudinal survey over a period of 10 years was carried out on 286 community-dwelling elderly subjects aged 70 years at baseline. Clinical attachment level (CAL) was measured at six sites per tooth on all teeth present and periodontal disease progression was defined as CAL> or =3 mm., Results: Periodontal disease progression was found in 79% of the subjects and most frequently in maxillary molars. Multilevel logistic regressions revealed that subjects wearing removable dentures were significantly at risk for periodontal disease progression. Abutment teeth for removable/fixed dentures were also significantly more likely to suffer periodontal breakdown. Furthermore, the following tooth-related variables were found to be possible risk factors for periodontal disease progression: maxillary and multirooted teeth., Conclusion: Multirooted teeth and abutments for a fixed denture were possible risk factors for periodontal disease progression.

Statement of Problem: Little has been reported about the demographics of implant placement in the Irish population and the complications that occur. This is important in terms of service planning and providing patient information., Purpose: The purpose of this study was to construct a database of patients who had implants placed in the Dublin Dental School et Hospital from 2000 to 2006. Also, we wanted to compare the complications that occurred in patients who had overdentures to those with a fixed prosthesis., Methods: Hospital records were searched for all patients who had implants placed over a seven-year period and we recorded demographic information, as well as details of the implant site, implant type and restoration. Patients who had four or more implants placed for an implant-supported overdenture or fixed prosthesis were invited to attend for a clinical examination., Results: A total of 1,111 implants were placed in 452 patients over the study period--half of the implants supported single crowns, while the other half supported mainly overdentures and full arch fixed prostheses, with few fixed partial dentures. The 40- to 60-year-olds had the greatest number of implants placed of any age group and most implants were placed in the anterior region. Patients with implant-supported overdentures recorded more complications (52%) compared to those with fixed prostheses (32%). The most common complications associated with both treatments were gingival inflammation and peri-implant mucositis. Overdentures additionally had a significant number of retentive clip fractures., Conclusions: Implant-supported overdentures and fixed prostheses were both clinically successful. However, patients and clinicians should be aware that soft tissue and mechanical complications are common.

Purpose: The mandibular implant overdenture is a popular treatment modality and is well documented in the literature. Follow-up studies with a long observation period are difficult to perform due to the increasing age of patients. The present data summarize a long-term clinical observation of patients with implant overdentures., Materials and Methods: Between 1984 and 1997, edentulous patients were consecutively admitted for treatment with an implant overdenture. The dentures were connected to the implants by means of bars or ball anchors. Regular maintenance was provided with at least one or two scheduled visits per year. Recall attendance and reasons for dropout were analyzed based on the specific history of the patient. Denture maintenance service, relining, repair, and fabrication of new dentures were identified, and complications with the retention devices specified separately., Results: In the time period from 1984 to 2008, 147 patients with a total of 314 implants had completed a follow-up period of >10 years. One hundred one patients were still available in 2008, while 46 patients were not reexamined for various reasons. Compliance was high, with a regular recall attendance of >90%. More than 80% of dentures remained in continuous service. Although major prosthetic maintenance was rather low in relation to the long observation period, visits to a dental hygienist and dentist resulted in an annual visit rate of 1.5 and 2.4, respectively. If new dentures became necessary, these were made in student courses, which increased the treatment time and number of appointments needed. Complications with the retention devices consisted mostly of the mounting of new female retainers, the repair of bars, and the changing of ball anchors. The average number of events and the rate of prosthetic service with ball anchors were significantly higher than those with bars. Twenty-two patients changed from ball anchors to bars; 9 patients switched from a clip bar to a rigid U-shaped bar., Conclusions: This long-term follow-up study demonstrates that implant overdentures are a favorable solution for edentulous patients with regular maintenance. In spite of specific circumstances in an aging population, it is possible to provide long-term care, resulting in a good prognosis and low risk for this treatment modality. For various reasons the dropout rate can be considerable in elderly patients and prosthetic service must be provided regularly.

Aims: The primary aim of this study was to evaluate the 1-year crestal bone loss and success rate of an immediately placed single-stage implant placed and restored by novice operators. A secondary aim was to determine the patient's assessment of the appearance of the final restoration., Methods: Fifty-one patients received a tooth extraction and placement of at least 1 immediate implant by a Graduate Periodontics resident. Clinical and radiographic measurements were taken at the surgical, 4-month, and 1-year follow-up visits. After at least 3 months healing, dental students restored the implants with either a crown or an overdenture. Patient satisfaction was assessed using 5 categories: excellent, very good, good, fair, or poor., Results: Sixty-two immediate implants were placed. The success rate was 100% at the 12-month visit and was subclassified as grade 3 because of the mean first year bone loss of 1.3 +/- 1.0 mm. Using the 2008 classification of Misch et al, 42 implants were classified as success optimum health, 19 as survival satisfactory health, and 1 as survival compromised health. Radiographic bone loss was stratified by implant platform position relative to the alveolar crest and changed from time 0 to time 12 by -1.0 +/- 1.2 mm for the supracrestal group (n = 25, P < 0.05), -1.5 +/- 0.9 mm for the crestal group (n = 31, P < 0.05), and -1.3 +/- 1.2 mm for the subcrestal group (n = 6, P < 0.05). The supracrestal group had significantly less bone loss than either the crestal or the subcrestal group (P < 0.05). The appearance of the final restoration at 1 year was rated excellent by 82% of patients, very good by 16%, and good by 2%., Conclusions: Immediate implant placement by novice operators using routine dental school procedures was a highly predictable procedure as indicated by the 100% success rate at 12 months. Most patients rated the restoration appearance as excellent.

This study sought to quantify the incidence of root canal treatment (RCT) failure and identify its predictors in root canals that were performed or referred by general dentistry practices in a practice-based research network (PBRN). This retrospective cohort study involved 174 endodontically treated teeth. Mean duration from initial therapy to follow-up was 8.6 years. Permanent restorations were ultimately placed in 89% of teeth, although 18% of teeth were ultimately extracted anyway. Receiving a permanent restoration was a significant predictor of treatment failure (in other words, patients who did not receive a permanent restoration were more likely to experience RCT failure), whether failure was determined clinically or radiographically. This study of PBRN practices suggests a higher failure rate compared with studies that utilized highly controlled environments or populations with high levels of dental insurance.

Objective: To investigate primary care practitioner participation in implant-supported mandibular overdenture (ISOD) provision., Design: Postal questionnaire., Setting: Primary dental care, North East England 2007., Subjects and Methods: Two hundred and ninety-five practitioners in North East England were sent questionnaires presenting a case-based scenario of a patient unable to manage a lower denture on an atrophic ridge. The questionnaire led them through the facilitation stages of ISOD provision, asking them to state their anticipated level of participation at each stage. Demographic details were also collected., Results: Two hundred and seventeen responses were received (74%). Most practitioners would consider the option of provision of ISODs (89%) in this case and all who considered would discuss the option with the patient. Of those offering to facilitate treatment, 66% (122/184) would never deliver themselves, with the majority (60%, 111/184) referring within primary care. Statistical analysis showed associations between demographics and behaviour., Conclusions: The majority of practitioners in this study area would facilitate ISOD provision in this case. Practitioners who are male and working in a practice where a framework for the provision of implants already exists are most likely to facilitate provision and/or provide an ISOD within primary care.

Background: The aims of this study were to evaluate the long-term survival rates of short dental implants in posterior areas and to analyze the influence of different factors on implant survival., Methods: A retrospective cohort study design was used. A total of 293 subjects received 532 short implants between 2001 and 2004. All implants were placed by two experienced surgeons, and rehabilitations were done by three prosthodontists. Each implant failure was analyzed carefully. The potential influence of demographic factors, clinical factors, surgery-dependent factors, and prosthetic variables on implant survival was studied. Implant survival was analyzed using a life-table analysis (Wilcoxon [Gehan] test)., Results: The overall survival rates of short implants were 99.2% and 98.7% for the implant- and subject-based analyses, respectively. The mean follow-up period was 31 +/- 12.3 months. Two of 532 implants were lost during the observation period. None of the variables studied were statistically associated with implant failure., Conclusion: Treatment with short implants can be considered safe and predictable if used under strict clinical protocols.

The overdenture is, perhaps, an under-used form of treatment in the primary dental care sector. In this, the final paper in a series of three, the reader will be reminded of the basic concepts concerning overdentures. The author will outline some of the important changes that are likely to influence overdenture provision in the United Kingdom, and describe clinical aspects of this form of treatment.

In an effort to make the implant overdenture more affordable for patients, a pricing package at the University of Alabama at Birmingham School of Dentistry was established. This package includes two implants, two dentures (upper and lower), and two implant abutments, all for $975. It is known as the "2-2-2" implant program. One concern regarding the program was whether patients would complete overdenture treatment or simply receive implants at this relatively low cost and have the implants restored outside the school. The purpose of this retrospective chart review was to determine how many patients in 2004 received implants as part of this program and how many of these patients completed overdenture treatment. Other data (age, distance from school, number of teeth at start of treatment, and gender) were collected to identify variables that might be associated with greater likelihood of completing overdenture treatment. In 2004, fifty-one patients received 102 implants as part of this program. Two patients had a failed implant prior to restoration (two of 102 implants), and one patient was referred to graduate prosthodontics for restoration. Of the remaining forty-eight patients, forty-one completed overdenture treatment (85 percent), and seven (15 percent) were lost to follow-up. The mean age of patients receiving this treatment was 60.7 years. The mean distance traveled to the school was 70.7 miles. While no variables showed significant predictive value, point estimates (estimate of the odds ratio) suggest that older patients and patients who travel greater distance to the school were less likely to complete treatment. The low-cost implant overdenture has been an important addition to our curriculum. The majority of patients who receive implants as part of this program complete overdenture treatment.

Background: Implant-supported overdentures have been a common treatment for edentulous patients for the past 20 years, achieving good clinical results. The purpose of this study was to examine survival and success rates of implants supporting overdentures in the maxilla and mandible and to examine the influence of factors related to patients, implant procedure, implant data, and follow-up period on implant success., Methods: During a 10-year period (1990 to 2000), 285 implants were placed in 62 patients to support 69 overdentures (seven patients had overdentures in both jaws). Patients ranged in age from 45 to 85 years (mean 64.5 years). The files of 61 patients, including 277 implants supporting 68 overdentures (14 maxillary and 54 mandibular), had measurable radiographic post-exposure follow-up (range 6.63 to 110.93 months, mean 37.93 months) for cervical bone loss (CBL) measurements. Bone loss was measured by radiographic examination in which the mean number of exposed threads in mesial and distal sides of the implant was considered. Implants were rehabilitated by overdentures with bar (N = 52) or ball (N = 16) attachments., Results: Implant survival rate was 96.1% (11/285 did not survive) and total 10-year cumulative survival rate was 95.4% (maxilla, 83.5%, mandible, 99.5%). The success rate was 70.4% (maxilla, 41.9%; mandible, 80.8%) when using Albrektsson et al. success criteria. A logistic regression analysis showed that the maxilla (P <0.0001) and a short follow-up period (up to 5 years) (P = 0.017) were the most influencing factors enhancing CBL., Conclusions: 1) Survival of implants supporting overdentures was very high; 2) implants supporting overdentures in the maxilla had greater CBL than in the mandible; and 3) new criteria of implant success should be considered.

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.

The aim was to examine the use of mandibular implant overdentures in Swedish prosthodontic specialist clinics. Questionnaires related to treatment with mandibular implant overdentures during 2001 were sent to the heads of the 30 prosthodontic specialist clinics of the Public Dental Health Service in Sweden. Completed questionnaires were received from 28 (93%). The number of treatments with mandibular implant overdentures varied much among the clinics (0 to 22). Seven clinics had not performed any such treatment, and the median number was 2. The number of fixed implant-supported prostheses was much higher (median value 17, range 4 to 100). The correlation between the number of implant overdentures and fixed implant-supported prostheses in edentulous mandibles was weak (r = 0.33; P = 0.10). The most common anchorage system was ball attachments on two unsplinted implants. The most common reason for the choice of the overdenture treatment was the reduced cost, whereas the patient's main wish to improve denture retention came next. The question whether the demand for implant overdentures had increased during the last few years, was answered with "no" by 19, with "yes" by 5 and with "don't know" by 4 clinics. All but one responded that their attitude to implant overdentures had not changed after the introduction of free pricing in Swedish dentistry. It can be concluded that compared to the rapidly increasing international use of mandibular implant overdentures, this treatment of edentulous patients is rare in Sweden, where fixed implant-supported prostheses still are predominant.

Statement of Problem: In this preliminary study, an attempt was made to measure in vivo forces simultaneously on 5 maxillary implants with different types of superstructure., Material and Methods: Force measurements were carried out on 1 test patient with 5 ITI implants in the edentulous maxilla. A screw-retained fixed complete denture and an overdenture were fabricated for comparative measurements of forces. The overdenture could be mounted to 2 different types of bars. The measuring method was used with piezo-electric force transducers that were directly mounted onto the implants. This allowed for simultaneous measurements of forces in 3 dimensions, ie, in axial and transverse directions. Static and functional forces such as maximum biting (clenching), biting on a bite plate, and chewing food were registered. All measurements were repeated in the same way 2 years later., Results: The registered forces exhibited similar force patterns with both types of superstructure and both types of bars for overdenture connection. The force magnitudes were significantly different for the 3 dimensions (P<.05) with highest forces along the implant axis. On the posterior implants, force magnitudes were significantly higher (P<.05) than on the anterior implants in all 3 dimensions. On the anterior implants, under some test conditions, the transverse force components reached up to 100% of the axial force or even exceeded it during the chewing of food. During maximum biting, no upward force (tensile force) was found on any implant with the fixed complete denture, but upward force was found on one anterior implant with the overdenture. When chewing food, small force magnitudes in upward directions were regularly found with both superstructures. The force patterns between the first and second registrations showed similar trends, and no obvious differences were found., Conclusion: From these results it was concluded that similar patterns of force transmission onto the implants are observed with a fixed complete denture and an overdenture connected to maxillary implants. The bar design did not significantly influence the force pattern.

Statement of Problem: There are few research studies concerning prefabricated posts overdenture attachment systems using multiple pull cycles., Purpose: This study tested 6 prefabricated post overdenture attachment systems (AccessPost Overdenture, ERA white and ERA grey, Flexi-Overdenture, O-SO and ZAAG) measured to simulate wear over a 2000 pull cycle and compared the in vitro retention, measured (pounds)., Material and Methods: Records of the pounds of force necessary to separate each system were made at the beginning of testing, at pull 10 and then at every 50th pull until the 2000th pull was attained. All pulls were performed manually with a Shimpo force gauge. Absolute force (AF) and relative force (RF) were compared, AF being the force required at any pull to separate the overdenture device, whereas RF is the force required at the first pull., Results: There was considerable difference of the force required at pull 1 for the ERA white, O-SO and ZAAG anchor systems, then the AccessPost overdenture, and finally the Flexi-Overdenture and ERA grey attachment systems., Conclusion: At pull 2000, there was no statistical difference between any of the attachments studied. The amount of force necessary to offer functional retention to a specific patient wearing an overdenture may vary considerably, depending on the many factors in fabricating the overdenture, and the age, strength, musculature, and the expectations of the patient.

Statement of Problem: There is insufficient evidence to indicate the functional superiority of mandibular implant-supported overdentures to justify their use in edentulous patients., Purpose: This study compared the benefits perceived by patients who received a new maxillary denture and a mandibular conventional denture (CD) and an implant-supported overdenture (IOD)., Method: New maxillary and mandibular dentures were delivered to 89 diabetic denture wearers with clinically acceptable metabolic control who treated their diabetes either with insulin (IT) or without insulin (NIT). Of the 89 patients, 37 received maxillary and mandibular CDs and 52 received a maxillary CD and an IOD. Two questionnaires with categorical responses were used; the first contained 13 questions to ascertain a patient's absolute assessments of original dentures at entry and study dentures at 6- and 24-months after treatment completion; the second questionnaire had 11 questions that assessed the relative change perceived by patients with study dentures. Of the 78 patients who completed the posttreatment (PT) assessments at 6 months, 68 patients provided longitudinal data for questionnaire I and cross-sectional data for questionnaire II. In addition, 46 patients (18 CD and 28 IOD) also provided PT assessments at 24 months., Results: Both mean scores and percentage distributions of longitudinal data for questionnaire I showed perceptual improvements with both types of study dentures. Improvements were higher in the IOD than in the CD group. Mean scores failed to show any significant differences between the 2 treatment groups. The only significant difference was found in the change in percentage distributions for perceptual chewing ability in favor of the IOD group. Even this advantage was lost at 24 months. With the comparative questionnaire, a higher percentage of patients in the IOD group than in the CD group perceived improvements with study dentures from their original dentures in chewing ability, chewing comfort, and denture security. However, mean differences were statistically significant in favor of the IOD group only for chewing ability and less difficulty to chew hard foods., Conclusion: The mandibular implant-supported overdenture offers same advantage in terms of perceived chewing function over the conventional denture.

This study investigated the experience of endossoseus implants in the U.K. - how success rates compare with other countries; the common causes of failure; early detection, definition and treatment of the failing implant. Information was gathered by means of a questionnaire sent to 120 centres in the U.K. Thirty-nine centres responded to the survey, reporting on a total of 5328 implants which had been placed over an average time period of 6.5 years. A mean failure rate of 4.3% was reported in the mandible with 16% in the maxilla. The survey showed that 11 different implant systems were in use and that implants were used to support an overdenture in 56% of cases, and bridgework in 26%. The definition of the failing implant and the causes of failure were unclear, with a wide range of opinions given. A combination of methods were used to treat the failing implant including surgical techniques and chemotherapeutic agents, but the long-term success of these treatments was uncertain. Failure rates especially in the maxilla at some of the centres appear higher than have been previously suggested in the U.K. or abroad. Universal agreement on the criteria for 'success' and 'failure' of fixtures is needed along with agreed treatment protocols for the failing implant.

This paper reports on 10 years of clinical experience with implant prosthodontic treatment of total edentulism. During this period, of the 735 implants that were inserted, only 19 were lost, a 97.4% success rate. The authors believe that evaluating the success of implant treatment requires examining the health of the peripilastrium with periodontologic methods. The indices the authors used for such an evaluation were plaque accumulation, crevicular fluid flow rate, and sulcus bleeding; crevicular fluid flow proved the most satisfactory for estimating the health of peri-implant tissues. The results demonstrate that peri-implant-tissue health is similar to that of the tissues surrounding nontreated natural teeth and better than that of the tissues surrounding natural teeth wearing crowns.

Sensitivity or pain of the mucoperiosteum covering the mandibular edentulous ridge is often thought to limit bite forces in complete-denture wearers. Therefore, bite forces with mandibular implant-retained overdentures may depend on the degree of implant support. This study analyzed the effects of different degrees of support for the mandibular denture on bite forces measured four years after denture treatment as part of a randomized controlled clinical trial. All subjects had received new maxillary dentures and (1) mainly implant-borne overdentures on a transmandibular implant (TMI), (2) mucosa-borne overdentures on two cylindric permucosal IMZ implants, or (3) new conventional dentures in the mandible. Fifty-three women and 15 men (mean age, 59.1 yrs; range, 41 to 77) participated in this trial. Both unilateral and bilateral bite forces were recorded at different positions with a miniature strain gauge transducer and a mechanical bite fork, respectively. The subjects were asked to bite at three force levels. Results indicated that women had significantly lower maximum bite forces than men. Persons with mandibular implant-retained overdentures had significantly higher unilateral and bilateral maximum bite forces than complete-denture wearers. However, bite forces did not differ between the mainly implant-borne (TMI) and mucosa-implant-borne (IMZ) implant systems. Therefore, it appears that differences in support for the mandibular overdenture by dental implants are not reflected in bite force capabilities.

Although it has been shown that patients are more satisfied with prostheses supported by implants than with conventional dentures, there have been few direct comparisons of the various designs of implant-supported prostheses. This within-subject crossover clinical trial was designed to compare two forms of removable prostheses which are frequently prescribed for the edentulous mandible: a long-bar overdenture supported by 4 implants and a two-implant hybrid overdenture. Sixteen completely edentulous subjects were given a new maxillary conventional denture: Ten of them received the mandibular long-bar prosthesis first and six the hybrid. After a two-month adaptation period, psychometric measures of various aspects of the prostheses and physiological tests of masticatory efficiency were carried out over three weeks. The mandibular prostheses were then changed and the procedures repeated. At the end of the study, subjects were asked to choose the mandibular prosthesis that they wished to keep, and final psychometric measures were taken. In this paper, the results of the psychometric assessment and patient preference are presented. Subjects assessed factors such as general satisfaction, quality of life, stability, retention, comfort, esthetics, ease of cleaning, speaking, and chewing, and how well-chewed foods were before being swallowed. Most of the factors except ease of cleaning and speaking were rated significantly better with long-bar overdentures than with hybrid ones. These results are consistent with the fact that all subjects chose long-bar overdentures, reporting stability, ease of chewing, and comfort as the most important factors influencing their choice. These results suggest that, although subjects assign high ratings for most factors to hybrid overdentures, they find long-bar overdentures to be significantly more stable, comfortable, and easier for chewing.

Statement of Problem: The success of an implant system is often judged on the survival rate of the separate implants. This does not give a complete view of the "real" success of a system. To make that possible the total clinical performance, surgical and prosthetic, has to be considered., Purpose: This study aimed to set up a clinical performance scale for different implant systems retaining mandibular overdentures., Material and Methods: All data regarding surgical and prosthetic complications incurred and treatment procedures needed after implant placement were collected from a group of 90 patients who were treated either with two root form implants connected with a bar and supporting a mandibular overdenture or with a transmandibular implant system that supported an overdenture. All items were scored into five categories on the scale, defined as the "clinical implant performance" scale. The Delphi method was applied to categorize each item. A panel of experts assessed the items., Results: After three rounds there was complete consensus between the experts for 65% of the items for the root form implant systems, and for 87% of the items at least five out of six experts gave the same score. For 55% of the items for the transmandibular implants systems there was complete consensus, and for 85% of the items at least five out of six experts scored in the same way., Conclusions: The Delphi method provides a useful scale for evaluating the clinical performance of implant systems retaining mandibular overdentures. The presented scale makes it possible to compare the overall performance of different implant systems for overdentures.

Treatment with overdentures is an alternative to conventional complete prostheses. Different types of attachments can be placed in natural teeth that act as retainers for overdentures. The photoelastic relationship between the design of the attachment and the distribution of occlusal forces among the abutment teeth and the distal alveolar ridges was examined. The results were used to develop a classification for clinical cases so that the correct attachment design can be selected.

Unlabelled: Dental implants have revolutionized dentistry in every aspect of treatment including surgery, restorative dentistry, and orthodontic treatment planning., Purpose: This retrospective study analyzes the treatment of completely and partially edentulous patients in a prosthodontics practice and the Edmonton Implant Seminar., Material and Methods: All implant surgery was performed by the prosthodontist. The majority of implants (336) were restored by the prosthodontist (71%). A total of 135 restorations were provided by 12 different general practitioners (29%) in a study group environment., Results: Of 471 implants that were placed, 453 (96.2%) integrated successfully. Treatment groups were divided into single implant restoration (19.3%), fixed partial dentures (51%), overdentures (12.3%), and mandibular fixed partial denture cantilever (17.6%). Retention of final prosthesis was 99.4%. Of 18 failures, four occurred between Stage I and II surgeries, 11 occurred between Stage II surgery and final impressions, and three occurred after placement of final restorations. All three restorative failures were single implants., Conclusion: The results indicated that implant placement by a prosthodontist is comparable to the success of previous studies.

Objectives: This report covers a series of three different clinical longitudinal studies on the outcome of overdenture therapy when two (mandible) or four (maxilla) implants retaining a resilient overdenture are used., Conclusions: The resilient mandibular bar-retained overdenture on two implants is a very reliable treatment. Implant failure is low and the stability of the implants improves over time. Marginal bone remains stable once the first year has passed. The applied overdenture design is simple, versatile and very cost effective. In the maxilla such implants do maintain their marginal bone level if splinted by means of a rigidly cast bar and when applied in a resilient overdenture therapy. Correct laboratory fabrication of the prosthesis is critical to the success of treatment. Clinically, overdenture aftercare is limited to renewal of used attachments. Patient satisfaction remains very positive to this form of treatment.

Objectives: In the Netherlands, dental implants have been included in the National Dental Insurance Scheme (NDIS) since 1989. Nowadays, out-of-pocket expenditure is low, making implant treatment financially feasible for a large group of edentulous, potential implant candidates. Treatment can be performed by both oral surgeons and general dentists. Results of implant treatment in the literature are usually obtained in academic and specialized centers. In contrast to this, the present study evaluates the quantitative and qualitative aspects of rehabilitation with oral implants in combination with an overdenture when applied on a nationwide scale., Methods: For this purpose all patients (n = 5410) treated between January 1989 and July 1992 were extensively documented pre-operatively, implant patients (n = 429) were clinically investigated by two independent observers and the effect of treatment on denture complaints was assessed by means of a questionnaire (n = 460)., Results: Only a small proportion of the potential pool of implant candidates is actually being treated, to a constant number of approximately 2000 patients a year. The selected patients have major denture problems and have received relatively high levels of prosthetic care during the last decade. Clinical results are comparable to those reported in the literature, implant survival after 3 years for the lower jaw being 96.3% and for the upper jaw 70.4%. Oral hygiene was frequently considered suboptimal and seen in conjunction with marginal inflammation of the peri-implant mucosa. Subjective results were excellent, patients were quite satisfied with the improvements in the comfort and esthetics of their lower denture., Conclusions: Implant-overdenture treatment, within the guidelines and regulations set by the Dutch NDIS, is a safe and effective treatment alternative, in particular for the rehabilitation of the lower jaw.

This retrospective study aims to identify factors that contribute to either a poor or excellent treatment result in implant-overdenture treatment. A total of 375 implants, in an equal number of patients were included in the study. A clinical examination was performed by 2 observers. Gingival health and oral hygiene were assessed and additional complications were noted, including implant loss. 2 outcome variables, STATUS1 and STATUS2, were constructed that were different with respect to treatment outcome, representing a poor and an excellent result, respectively. Patient variables such as age, gender, medical status and prosthetic history were collected pre-operatively with a questionnaire. Life table analyses were used to test subsets of patient and treatment variables for differences in survival distribution, both for poor or excellent results. With regard to predictors of poor results; implants in the upper jaw were associated with a poorer outcome than those placed in the lower jaw (p = 0.01). When more than 2 implants were placed, the quality of survival was also impaired (p = 0.03). Interestingly, implants in patients with a self-proclaimed history of tooth loss due to periodontitis appear to have a far poorer treatment outcome than implants placed in patients without such a history (p = 0.01). No other variables could be related to a poor result after 3 years. None of the variables could predict an excellent treatment outcome.

There is a controversy among prosthodontists concerning the most favourable superstructure design of a prosthesis supported by implants. Some investigators used the fully extended denture, others used a non extended. This study evaluated the load distribution pattern occurring in implants with the two designs. A real clinical situation which includes 4 osseointegrated implants that are connected to each other with a superstructure bar and support an acrylic dentures was transferred into a 3-D geometric model. With the 3-D FEM it was possible to compare between the two types of acrylic dentures.

Over 6 years of the implant programme in the University of Otago School of Dentistry, the rate of use of osseointegrated implants to support or retain a dental prosthesis has increased. This increased use has been most marked in young adults who have required the restoration of a single space in the anterior maxillae. The treatment outcome is unequivocally positive, with an overall fixture retention rate of over 99 percent.

In order to evaluate the possibility of using endosseal implants (ITI Dental Implant System) and implant-retained prostheses for 65-year-old patients from a medium-sized Finnish city, 431 such patients were examined by means of panoramic radiographs. The population represents 61% of the total age group in the city (born in 1923). The possibility to construct a prosthesis, anchored on implants, was evaluated in three different groups. It was shown that in group I (edentulous maxilla and mandible, 256 patients) all male and 97% of female subjects could have been treated with implant-retained over-dentures in the lower jaw. Corresponding figures in the upper jaw were 62% for males and 59% for females. In patients with edentulous maxilla and dentulous or partially edentulous mandible (group II, 84 subjects) implant-retained overdenture in the maxilla could have been possible in 52% of male and 43% of female participants. In subjects with own teeth left in both jaws (group III, 91 participants) some kind of implant-retained bridge or single implants could have been constructed in 70% in maxilla and in 92% in mandible.

Since 1989 implant dentistry in the Netherlands is a National Dental Insurance (NDI) benefit, thus reducing out-of-pocket expenditures for implant candidates considerably. A nationwide investigation was set up in order to evaluate quantitative, qualitative and financial effects of this new provision. The patient and treatment characteristics of 5410 edentulous implant candidates are discussed. Intensive monitoring of the usage of these new regulations facilitates health care policy making, including future planning. Over a 3 1/2 yr period, two out of every thousand totally edentulous NDI patients were treated in combination with dental implants. This number is being considered small, bearing in mind the number of edentulous patients in the Netherlands and the proportion of dissatisfied denture wearers. Demographic data, prosthetic and pre-prosthetic surgical history reveal that these patients, mostly female and middle-aged, experience severe denture-related problems. In the majority of cases the implants are placed by an oral surgeon and the suprastructure is made by a general dentist or at a centre for special dental care. The treatment itself mostly consists of an implant retained overdenture on two or four permucosal implants and a bar-construction.

The retreatment need was assessed in 148 patients wearing 125 overdentures in the mandible and 56 in the maxilla. The total number of abutment teeth was 512. During the evaluation period 44 abutments were extracted. The endpoints of the survival analysis after 6 yr were 89%, taking the loss of all abutments as the failure criterion for overdentures. During the clinical examination it was found that 31% of the abutments needed treatment while the retrospective part showed a mean yearly restoration need of 17.5%. Caries was the most important reason for retreatment. These data demonstrated that patients with overdentures should be regarded as high risk patients for retreatment of abutments. Therefore a stringent maintenance program, including regular recall appointments and the application of a preventive regimen, is desirable.

The purpose of this study was to determine the effects of implant-overdenture treatment (IOT) on patients' complaints about dentures and the degree to which subjective treatment outcome could be predicted from baseline patient and treatment characteristics. Four groups of patients were distinguished: one pretreatment group, two posttreatment groups (1 year after treatment) and one reference group of denture wearers, who had not applied for any kind of treatment. They finished a questionnaire with 20 statements on denture complaints. Four scales concerning denture complaints could be distinguished and named after their underlying variables. Differences between the groups were analyzed. IOT treatment was shown to be very effective on a wide range of denture complaints. Little change was seen in patient satisfaction with regard to maxillary dentures when measured on the scales, although many patients wanted improvement in retention and stability for the maxillary denture after IOT treatment in the mandible. Sixteen percent of the denture wearers who had not applied for IOT expressed complaints regarding their mandibular dentures that matched or were more severe than those of the patients that had applied for IOT, before the actual start of treatment. Although generally the subjective treatment outcome of IOT was favorable, it could not be individually predicted from baseline patient and treatment characteristics.

This nationwide study was conducted to clinically evaluate treatment with implant-retained overdentures when applied on a large scale and to determine to what degree treatment results could be predicted from patient and treatment characteristics at baseline. A total of 429 patients who had received implant overdenture treatment were clinically investigated by two dentists. Implant survival was high, especially for implants placed in the mandible. Results for the maxilla appeared far less promising. Complications that were observed predominantly concerned inflammation of the peri-implant tissues and poor oral hygiene. The quality of the overdentures, as assessed on three conventional prosthetic parameters, was generally good. Nevertheless, overdentures on oral implants appear to require considerable maintenance. No statistically significant correlation could be found between patient and treatment characteristics at baseline and the clinical treatment outcome. So, although treatment outcome with implant-retained overdentures appeared favorable, clinical results were not individually predictable.

This study reviewed the prosthodontic treatment and aftercare required by 29 patients with 32 implant-supported prostheses (12 fixed and 20 removable) placed on 107 implants. Patients were followed for 4 to 39 months. The majority of implant-supported prostheses (53%) were placed in the mandible. Visual analogue scales were used by the patients to rate their satisfaction with their prostheses and their chewing ability. Approximately one third of the patients studied required three or more relines of their existing dentures between first- and second-stage surgeries, while over half of the definitive implant-supported prostheses required a major adjustment or repair. Removable prostheses required 78% of the total repairs and accounted for 80% of those prostheses that needed repeated repairs. In general, patients were very satisfied with their implant-supported prostheses, but 17% complained of mild speech difficulties and 7% noted slight difficulty in cleaning their fixed prostheses. Overall, the short-term prosthetic management required for the implant-supported prostheses in this study was substantial, particularly with the removable prostheses, and this should be taken into account when evaluating prosthetic options.

In an uncontrolled retrospective recall study of 57 patients treated with conical crown retained dentures, 60 restorations (37 in the maxillae and 23 in the mandible jaw) with a mean wearing time of 30.1 months (range 4 to 76) were evaluated. Of the 248 abutments, eight (3.2%) had been lost. Clinically healthy mucosa was seen in 35 jaws. The marginal fit of the copings was judged to be good. No caries or new restorations were observed in 44 patients. Thirteen patients had 19 surfaces with new restorations and 20 surfaces with caries lesions. Of these 39 surfaces, 38 were located subgingivally.