Mini-Implants for Mandibular Overdentures: Cost-Effectiveness Analysis alongside a Randomized Trial.

Mandibular overdentures retained by 2 conventional implants have been considered the standard of care for complete edentulism, according to the McGill and York consensuses. However, many patients refuse this treatment modality due to the associated costs and postsurgical discomfort. Mini-implants have the chance to overcome these limitations due to their potentially lower costs and a relatively uncomplicated surgical technique. This study compared treatment costs and incremental cost-effectiveness following the insertion of mini-implants (2 or 4) or 2 standard-size implants for the retention of mandibular overdentures, by means of a randomized clinical trial. In total, 120 edentulous participants (mean age 59.5 ± 8.5 y) were randomly allocated into 3 groups according to treatment received: 4 mini-implants (group 1), 2 mini-implants (group 2), or 2 standard implants (group 3). Treatment costs and outcomes (Oral Health Impact Profile for Edentulous [OHIP-EDENT] and satisfaction with the dentures) were evaluated after 6 mo. Incremental cost-effectiveness ratios (ICERs) were calculated for each intervention in terms of cost per 1-point change in patient outcomes. A 1-way sensitivity analysis was performed considering a 95% confidence interval variation in cost and outcome parameters, represented in tornado diagrams. Overall treatment cost was the lowest for group 2 (average cost: US$318.08), followed by group 1 (US$510.75) and group 3 (US$566.13). Groups did not differ in terms of the length of unscheduled appointments and time spent by participants. In summary, our findings indicate that mandibular overdentures retained by 2 or 4 mini-implants are less costly compared to 2-implant overdentures. Despite the lower costs of overdentures retained by 2 mini-implants, those retained by 4 mini-implants showed further improvement in patient-reported outcomes and reduced costs compared to standard implants ( ClinicalTrials.gov NCT01411683). Knowledge Transfer Statement: This report shows that mini-implant retained overdentures are less costly than overdenture treatment on 2 standard-sized implants. Treatment with 2 mini-implants is an effective procedure to substantially save resources, whereas treatment with 4 mini-implants provides better results from a patient perspective combined with slightly reduced costs compared to the treatment with 2 standard implants. Therefore, mini-implant overdentures may be effective and more accessible than overdentures on 2 standard-size implants for those with limited incomes.

A pilot randomised controlled trial evaluating mini and conventional implant retained dentures on the function and quality of life of patients with an edentulous mandible.

BACKGROUND: Total tooth loss (edentulism) can be a debilitating condition, impacting on ability to chew, speak and interact with others. The most common treatment is with complete removable dentures, which may be successful, but in the lower jaw, bone resorption that worsens over time makes denture-wearing difficult. Two dental implants in the mandible to retain the lower denture has been advocated as the gold standard of treatment, but has not been universally provided due largely to financial constraints and also patient fear. Mini implants (MI) are cheaper and less invasive than conventional implants (CI), but may not have equivalent longevity. Therefore, it is unknown whether they represent a cost-effective treatment modality over time. The aim of this pilot randomised controlled trial was to assess the feasibility of carrying out a trial on this cohort of patients, and to inform the study design of a large multicentre trial. METHODS: Forty-six patients were randomly allocated to receive either two mini implants or two conventional implants in the mandible to retain their lower dentures. Quality of life (QoL) questionnaires, pain and anxiety scores, and an objective "gummy jelly" chewing test were carried out at multiple timepoints, along with detailed health economics information. Implants were placed one-stage, and an early loading protocol was utilised. Patients were reviewed 8 weeks post-placement, and finally at 6 months. Implant failure, recruitment and retention rates were recorded and analysed. RESULTS: The pilot study demonstrated that it is possible to recruit, randomise and retain edentulous (mainly elderly) patients for an implant trial. We recruited to target and retention rates were acceptable. The large number of questionnaires was onerous for participants to complete, but the distribution of scores and feedback from participants helped inform the choice of primary and secondary outcomes in a full trial. The chewing test was time-consuming and inconsistent. Implant failure rate was low (1/46). The data on indirect costs gathered at every visit was viewed as repetitive and unnecessary, as there was little or no change between visits. CONCLUSIONS: The pilot study has shown that acceptable recruitment and retention rates are achievable in this population of patients for this intervention. The results provide valuable information for selection of outcome variables and sample size calculations for future trials. TRIAL REGISTRATION: (ISRCTN): 87342238 Trial registration date: 05/07/2013.

Digital data acquisition for a CAD/CAM-fabricated titanium framework and zirconium oxide restorations for an implant-supported fixed complete dental prosthesis.

This dental technique report describes a digital workflow with digital data acquisition at the implant level, computer-aided design and computer-aided manufacturing fabricated, tissue-colored, anodized titanium framework, individually luted zirconium oxide restorations, and autopolymerizing injection-molded acrylic resin to fabricate an implant-supported, metal-ceramic-resin fixed complete dental prosthesis in an edentulous mandible. The 1-step computer-aided design and computer-aided manufacturing fabrication of titanium framework and zirconium oxide restorations can provide a cost-effective alternative to the conventional metal-resin fixed complete dental prosthesis.

[Cost-effectiveness when treating an edentulous mandible]. / Kosteneffectiviteit bij de behandeling van een edentate onderkaak.

When treating an edentulous patient with complaints of unsatisfactory retention of his complete mandibular denture, various treatment options are available: a new conventional denture, an implant-supported overdenture, and an implant-supported fixed partial denture. Important considerations during the decision-making process are patient satisfaction, cost of denture fabrication, and cost of maintenance. The outcome of the diagnostic procedure will have financial consequences. On that basis, a satisfactory treatment plan can be established and carried out. The need exists for a protocol which takes into account cost-effectiveness and is useful in selecting the appropriate treatment option, adjusted to individual requirements.

A randomized clinical trial comparing patient satisfaction and prosthetic outcomes with mandibular overdentures retained by one or two implants.

PURPOSE: This randomized clinical trial tested hypotheses that there are no differences in patient satisfaction, component costs, or treatment and maintenance times when mandibular overdentures are retained by one or two implants. MATERIALS AND METHODS: Subjects wearing conventional complete dentures were randomized to receive either one midline or two bilateral mandibular implants followed by a mandibular denture reline to incorporate implant retention. They indicated on a visual analog scale satisfaction with their dentures before implants and at 2 months and 1 year after implant retention. Satisfaction outcomes between the two groups were compared using the Wilcoxon/Mann-Whitney nonparametric rank test, while changes within each group were analyzed using signed-rank tests. Component costs and times for surgery, prosthodontic treatment, and maintenance were compared using nonparametric and t tests. RESULTS: Eighty-six subjects enrolled in this study and 85 completed the 1-year follow-up, at which median satisfaction was 93 (maximum 100) in the single-implant group and 94 in the two-implant group (P > .5). Within each group, median improvement in satisfaction was similarly dramatic (approximately 44) and significant (P < .001). Prosthodontic maintenance time was similar for both groups (P > .37), but the single-implant group had significantly lower component costs (P < .001) and lower times for surgery (P = .002), postsurgical denture maintenance (P = .021), and denture reline (P < .001). Five implants failed in four subjects, all in the two-implant group and all before denture reline. CONCLUSION: Lower component costs and treatment times, with comparable satisfaction and maintenance time over the first year, indicate that a mandibular overdenture retained by a single midline implant may be an alternative to the customary two-implant overdenture for maladaptive denture patients.

An eight-year follow-up to a randomized clinical trial of aftercare and cost-analysis with three types of mandibular implant-retained overdentures.

Mandibular implant overdentures increase satisfaction and the quality of life of edentulous individuals. Long-term aftercare and costs may depend on the type of overdentures. One hundred and ten individuals received one of 3 types of implant-retained overdentures, randomly assigned, and were evaluated with respect to aftercare and costs. The follow-up time was 8 years, with only seven drop-outs. No significant differences (Kruskal-Wallis test) were observed for direct costs of aftercare (p = 0.94). The initial costs constituted 75% of the total costs and were significantly higher in the group with a bar on 4 implants, compared with the group with a bar on 2 implants and the group with ball attachments on 2 implants (p = 0.018). The last group needed a significantly higher number of prosthodontist-patient aftercare contacts, mostly for re-adjustment of the retentive system. It can be concluded that an overdenture with a bar on 2 implants might be the most efficient in the long term.

Treatment planning of the edentulous mandible.

Edentulism can be a debilitating handicap. Zarb described endentulous individuals who could not function as 'denture cripples'.(1) Most difficulty with complete denture prostheses arises from the inability to function with the mandibular prostheses. Factors that adversely affect successful use of a complete denture on the mandible include: 1) the mobility of the floor of the mouth, 2) thin mucosa lining the alveolar ridge, 3) reduced support area and 4) the motion of the mandible (Figs 1,2). These factors alone can explain the difficulty of wearing a denture on the mandibular arch compared to the maxillary arch. The maxilla exhibits much less mobility on the borders of the denture than the mandible, moreover having a stable palate with thick fibrous tissues available to support the prostheses and resist occlusal forces. These differences explain most of the reasons why patients experience difficulty with using a complete denture on the mandibular arch compared to the maxillary arch.

A cost-effectiveness analysis of implant overdentures.

Placement of dental implants may improve the retention and stability of complete dentures in edentulous patients. Treatment costs, however, substantially increase with implant treatment. We therefore performed a stochastic cost-effectiveness analysis, comparing implant-supported over-denture prostheses (4 implants), implant-retained overdentures (2 implants), and complete dentures, from the patient's perspective in Switzerland, to assess whether implant treatment in the mandible represents value for money spent. Twenty patients were included in each treatment group and were followed up for three years. Health outcomes were expressed in Quality-adjusted Prosthesis Years, and dental health care costs and time costs were recorded in year 2000 Swiss Francs (CHF 100 = US dollars 61). The cost per Quality-adjusted Prosthesis Year gained for implant treatment was CHF 9100 (2 implants) and CHF 19,800 (4 implants) over 3 years. Over a ten-year period, these threshold ratios were reduced to CHF 3800 (2 implants) and CHF 7100 (4 implants) per Quality-adjusted Prosthesis Year gained.

Two implants for all edentulous mandibles.

Complete dentures have always been a poor substitute for natural teeth. Mandibular complete dentures frequently cause pain and discomfort, accelerated residual bone resorption, while failing to restore effective chewing. The provision of two implants to stabilise the mandibular complete denture can result in significant improvements.

Can general dentists produce successful implant overdentures with minimal training?

OBJECTIVES: This study was carried out to determine whether inexperienced dentists can provide two-implant overdentures that are as satisfactory and of the same cost as those provided by experienced prosthodontists. METHODS: Edentulous elders were enrolled in a randomized controlled clinical trial to compare the effects of mandibular conventional and two-implant overdentures on nutrition. They were randomly assigned to groups that were treated by either an experienced prosthodontist or by a newly-graduated dentist with minimal training in implant treatment. Data for this study were obtained during the treatment of the first 140 subjects enrolled. The change in patient ratings of satisfaction after treatment, laboratory costs and the number of unscheduled visits up to 6 months following prosthesis delivery were compared. RESULTS: Satisfaction was significantly higher with implant overdentures than with conventional dentures, but there were no differences in scores for either prosthesis between the groups treated by experienced specialists or new dentists. Furthermore, six of the seven inexperienced dentists reported that they found the mandibular two-implant overdenture easier to provide than the conventional denture. CONCLUSIONS: The results of this study suggest that general dentists can provide successful mandibular two-implant overdentures with minimal training.

A prospective study on immediate loading of implants with mandibular overdentures: patient-mediated and economic outcomes.

PURPOSE: The aims of this report are to present the patient-based outcomes and associated clinical costs of an immediate loading protocol for mandibular overdentures in edentulous patients. MATERIALS AND METHODS: Two groups of patients were selected. Thirty-five consecutively treated patients received an immediate protocol, while 42 patients treated with a conventional protocol served as a historical control. Patient-based concerns for patients in the immediate group were measured at various stages of treatment with 2 questionnaires: the Denture Satisfaction Scale and the Oral Health Impact Profile. Direct clinical and time costs over a 1-year period were estimated and deflated to 2002 Canadian dollars. Salary rates by occupation, age, and gender were used to evaluate the patients' time costs. Treatment costs were compared between the 2 groups. Additionally, incremental cost-effectiveness ratios for various stages with the immediate protocol were calculated. RESULTS: Significant improvements posttreatment were observed with both the Denture Satisfaction Scale (Wilcoxon signed rank test, P < .05) and the Oral Health Impact Profile (Friedman test, P < .05). The immediate protocol was associated with higher maintenance costs, with resultant higher total costs (Mann-Whitney U test, P < .05). No difference was observed in the time costs associated with the 2 protocols. Within-group analysis of costs at various stages of the immediate protocol suggested that treatment with implant-supported overdentures was more cost-effective than treatment with conventional dentures. CONCLUSIONS: This study suggests that implants in 1 jawbone lead to a substantial improvement in perceived oral health status. Furthermore, the immediate loading protocol was not cheaper than a conventional protocol.

Cost-effectiveness of mandibular two-implant overdentures and conventional dentures in the edentulous elderly.

Implementation of new therapies is usually governed by financial considerations, so efficacy studies should also include cost comparisons. The cost and effectiveness of mandibular conventional dentures (CD, n = 30) and two-implant overdentures (IOD, n = 30) were compared in elderly subjects. Effectiveness (Oral Health Impact Profile, OHIP-20) and cost were measured up to one year post-treatment. Data for subsequent years were estimated by the Delphi method. Using an average life expectancy of 17.9 years, the equalized annual costs (in Canadian dollars) were dollar 399 for CD and dollar 625 for IOD (p < 0.001), and the equalized annual values for the outcome (OHIP-20) were 47.0 for CD and 31.3 for IOD treatment (p < 0.05). These values translate into a yearly additional cost for IOD treatment of dollar 14.41 per OHIP-20 point. These results are key to the implementation of programs to provide this form of therapy for edentulous adults.

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.

An economic evaluation of implant treatment in edentulous patients-preliminary results.

PURPOSE: Edentulous patients with denture problems benefit from implant treatment with overdenture prostheses. The aim of this prospective study was to investigate a method of analyzing cost effectiveness in dentistry. As an example, overdenture treatment with two or four implants was compared to the conventional complete denture (CD). MATERIALS AND METHODS: In a self-selected trial, 20 patients each were treated with implant-retained overdentures (two implants, IRET), implant-supported overdentures (four implants, ISUP), or CDs (control group) in the edentulous mandible. A cost-effectiveness analysis was performed from the patient's perspective, with a time horizon of 6 months. Direct health-care costs were calculated in Swiss Francs (in 2000), and effects were defined as improvements in perceived chewing ability compared with the baseline value before treatment (measured on a VAS). Point estimates for mean incremental cost-effectiveness ratios were complemented with cost-effectiveness acceptability curves to account for uncertainties associated with costs and effects. RESULTS: Mean incremental costs were CHF 4,329 (IRET-CD), CHF 13,360 (ISUP-CD), and CHF 9,031 (ISUP-IRET); these cost differences were all statistically significant. The mean incremental effects at 6 months were 19% (IRET-CD), 23% (ISUP-CD), and 4% (ISUP-IRET). Incremental cost-effectiveness ratios were CHF 228 (IRET-CD), CHF 581 (ISUP-CD), and CHF 2,258 (IRET-ISUP) per percentage increase in chewing ability. CONCLUSION: From an economic point of view, IRETs were more attractive than ISUPs. The latter were associated with a statistically significant improvement in perceived chewing ability compared to CDs, but at substantially higher costs.

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.

Does a prosthodontist spend more time providing mandibular two-implant overdentures than conventional dentures?

PURPOSE: In this article, the time taken by a prosthodontist to fabricate and maintain mandibular overdentures retained by two implants and conventional dentures is compared. MATERIALS AND METHODS: Sixty edentulous patients between the ages of 65 and 75 completed a randomized clinical trial. All received new maxillary conventional dentures and either a mandibular conventional denture (n = 30) or a two-implant overdenture on ball attachments (n = 30). The time spent by the prosthodontist and the number of visits required for treatment, including both scheduled and unscheduled visits, were recorded for each patient from preliminary impressions to 6 months following delivery. Data from the two groups were compared using Mann-Whitney U tests. RESULTS: The prosthodontist spent a mean total time of 296 minutes in treating an implant overdenture patient and 282 minutes on a conventional denture patient during the period from preliminary impressions to the 6-month follow-up. The mean numbers of appointments were 10.1 (implant group) and 10.8 (conventional group). These differences were not significant. CONCLUSION: Although additional knowledge is required to treat patients with implant prostheses, the time required by the prosthodontist to provide two-implant mandibular overdentures with ball attachments was not significantly different than the time needed for conventional denture treatment.

One-year prosthetic outcomes with implant overdentures: a randomized clinical trial.

PURPOSE: This randomized clinical trial examined implant overdenture (IOD) fabrication and maintenance time and costs, adjustment and repair incidence, and patient satisfaction after 1 year. MATERIALS AND METHODS: Sixty-four patients received 2 mandibular implants and an IOD with either a bar with 2 clips or 2 ball attachments for denture retention. RESULTS: Fabrication time, number of appointments, and chair time for adjustments were similar for the 2 denture designs. The most common adjustments for both types were to the IOD contours. Ball-attachment dentures required about 8 times longer for repairs than bar-clip prostheses. Approximately 84% of patients with ball-attachment dentures needed at least 1 repair, versus 20% of those with a bar-clip mechanism. The most common repairs were replacement of the cap spring or cap for the ball-attachment IOD and replacement of a lost or loose clip for bar-clip dentures. DISCUSSION: Patients were equally and highly satisfied with the improvements in function, comfort, and appearance with both types of IOD compared to their original conventional dentures. CONCLUSIONS: Given equivalent levels of patient satisfaction with either method of retention and a much higher repair rate for the ball attachment, it is suggested that a bar-clip design be used rather than the particular ball attachment utilized in this study.

Prosthetic complications in an implant-retained mandibular overdenture population: initial analysis of a prospective study.

STATEMENT OF PROBLEM: The clinical success of implant-retained, tissue-supported mandibular overdenture prostheses has been documented. However, few studies have evaluated the return visits and associated cost required to maintain these prostheses. PURPOSE: The purpose of this investigation was to evaluate the amount of maintenance required to provide acceptable and satisfactory implant-retained mandibular overdentures in a prospective clinical trial. MATERIAL AND METHODS: Fifty-eight patients received new maxillary and mandibular complete dentures followed by placement of microthreaded/TiOBlast implants in the mandibular left and right canine regions. At 3 months, ball abutments were placed, and the mandibular prostheses were relined to receive Dalla Bona-type ball housings (baseline). Prostheses were prospectively evaluated, and adjustments were made at 3-, 6-, 12-, 24-, and 36-month recall visits and at nonscheduled visits for 9 types of prosthetic complications. RESULTS: Of 58 patients, 6 required no adjustments. The remaining 52 patients made 327 return visits (including 194 nonscheduled visits) for prosthesis and/or abutment adjustments. One hundred and fifteen practitioner hours were required to provide prosthetic solutions to patient concerns at the return visits. The total estimated cost for all professional and laboratory services was $12,624.00 ($218.00 per patient). CONCLUSION: Although mandibular implant-supported overdentures with Dalla Bona-type ball attachments are an acceptable treatment option for edentulous patients, routine maintenance is required to ensure successful long-term outcomes.

The cost of dental implants as compared to that of conventional strategies.

The effectiveness of dental implants is widely studied, especially in terms of their clinical outcomes. However, from the policymaker's point of view, variables other than safety and efficacy, such as the costs and effectiveness of dental implants as compared to other treatment alternatives, are vital in decision making. This paper compares the costs of different treatment strategies in a randomized clinical trial in patients with resorbed mandibles and persistent problems with their conventional dentures: treatment with a mandibular overdenture on permucosal dental implants, an overdenture on a transmandibular implant, new dentures after preprosthetic surgery, and new dentures only. Data were gathered on an individual patient level to gain insight into specific cost episodes. Direct costs were subdivided into labor, material, technique, and overhead. Data concerning these components were gathered during the consecutive treatment phases in the first year. Results show that the resources used to treat a patient with an overdenture supported by a transmandibular implant are seven times those of a complete new set of dentures. Comparison of the cost ratio of an implant-retained overdenture supported by permucosal implants and conventional new prostheses proves less unfavorable: 1:3. New dentures after preprosthetic surgery are almost as expensive as treatment with permucosal implants.