Cost-effectiveness of Mandibular Two-implant Overdentures and Conventional Dentures in the Edentulous Elderly

The edentulous patient: the impact of implants on quality of life

Edentulism (total tooth loss) can be managed with four possible options: no prosthetic replacement, conventional complete dentures, implant-retained overdentures (removable), or implant-supported bridgework (fixed). Selection of these choices is influenced by social, medical, anatomical, technical, and economic factors. The care team involved in the decision-making process (be it patients, clinicians and occasionally commissioners of services) should be aware of the different treatment options and their potential impact on the patient's quality of life (QoL). The cost effectiveness of this impact can also be evaluated. Knowledge of the life-long sequelae of edentulism will also help practitioners guide patients in their treatment planning decisions when they may be approaching an edentulous state, preparing them for the challenges that may lie ahead. This paper aims to address the impact that edentulism has on QoL and the treatment options, focusing on the patient perspective.

Oral-Health-Related Quality of Life in Elderly Edentulous Patients with Full-Arch Rehabilitation Treatments: A Systematic Review

Background: The improvement of oral-health-related quality of life (OHRQoL) with different types of prosthesis for completely edentulous jaws in the elderly population is a critical factor in clinical decision making for these vulnerable patients. This review aims to evaluate the changes in OHRQoL after treatment with different types of full-arch prostheses in the elderly edentulous population to determine the prostheses that result in the greatest improvement in OHRQoL. Materials and Methods: Clinical studies of different types of full-arch prostheses that measured the OHRQoL in edentulous patients 60 years or older were searched for in the PubMed, Embase and Scopus electronic databases, with additional hand searching to summarize the outcomes of the selected studies. Result: Among the 302 identified studies, 10 studies were selected. A total of 504 patients wearing 133 complete dentures, 372 implant overdentures and 39 fixed prostheses were assessed among the selected studies. The overall OHIP and GOHAI scores were evaluated at baseline and in the 3rd, 6th, 12th and 18th months of treatment with the respective prostheses. The improved OHRQoL with overall OHIP scores associated with conventional dentures were 9.21-12.5% from the 3rd month to 1 year after treatment, whereas those associated with implant overdentures and full-arch fixed prosthesis were 9-25.26% at 1 year and 18.53-26.79 at the 18th-month follow-up, respectively. The increased overall GOHAI scores were 21.3-25.43% for conventional dentures, 36.82-41.32% for implant overdentures and 39.48-42.83% for full-arch fixed prosthesis from the 3rd month to the 6th-month follow-up. Conclusion: In general, the improvement in OHRQoL after rehabilitation with implant overdentures declined at one year, and that with full-arch fixed prosthesis declined at the 18th-month follow-up; meanwhile, the OHRQoL associated with conventional dentures improved stably up to one year, but the implant-supported prostheses resulted in an obviously greater improvement in the OHRQoL than that obtained with conventional dentures. However, studies with longer follow-up periods are still required to evaluate the long-term clinical effectiveness.

Surgical safety checklists for dental implant surgeries-a scoping review

OBJECTIVES

In both elective surgeries and aviation, a reduction of complications can be expected by paying attention to the so-called human factors. Checklists are a well-known way to overcome some of these problems. We aimed to evaluate the current evidence regarding the use of checklists in implant dentistry.

METHODS

An electronic literature search was conducted in the following databases: CINHAL, Medline, Web of Science, and Cochrane Library until March 2022. Based on the results and additional literature, a preliminary checklist for surgical implant therapy was designed.

RESULTS

Three publications dealing with dental implants and checklists were identified. One dealt with the use of a checklist in implant dentistry and was described as a quality assessment study. The remaining two studies offered suggestions for checklists based on literature research and expert opinion.

CONCLUSIONS

Based on our results, the evidence for the use of checklists in dental implantology is extremely low. Considering the great potential, it can be stated that there is a need to catch up. While creating a new implant checklist, we took care of meeting the criteria for high-quality checklists. Future controlled studies will help to place it on a broad foundation.

CLINICAL RELEVANCE

Checklists are a well-known way to prevent complications. They are especially established in aviation, but many surgical specialties and anesthesia adopt this successful concept. As implantology has become one of the fastest-growing areas of dentistry, it is imperative that checklists become an integral part of it.

Implant-Retained Mandibular Overdentures: Patient-Related Outcome Measurements after Seven Years of Function

Denture wearers often complain about jeopardized function and reduced quality of life due to lack of prosthesis’ retention. Implant-retained mandibular overdentures, on two non-connected implants (2IOD) are well-proven solutions to overcome these issues. We prospectively assessed 69 patients and scrutinized clinical records until at least seven years of function. Thirty-six were retained on Locator^® Abutments (LA) and thirty-tree on Ball Abutments (BA). Both systems were compared regarding the type, amount, and total cost of required maintenance. One implant was lost, yielding 98.7% survival after seven years. In total, 438 technical issues occurred: 121 (27.35%) in BA and 317 (72.4%) in LA. Out of these, 343 events (78%) were solved chairside: 191 (43.6%) were replacements of retention caps, 113 (25.8%) were minor acrylic repairs, 26 (5.9%) pressure ulcers had to be relieved, and 13 (3%) were related to abutments. LA required 179 insert replacements compared to 12 in the BA group. The overall initial treatment cost was EUR 3850 (base year of the analysis: 2003). The average total maintenance cost in relation to the initial cost for the LA and BA groups was 19.11 (range 0–82.24%) and 18.91% (range 0–113.26%) respectively (p = 0.540). Conclusions: The seven-year maintenance costs for a 2IOD is acceptable when the patient is regularly checked and professionally maintained. Most events are easily solvable chairside, but a few patients required more expensive interventions, regardless of the type of attachment used.

Access to denture restoration services under removable dentures subsidy program for adults aged 65 years and older in Taiwan- an interpretive approach

Background

Access is an important issue in health equality. Availability of dental services and cost subsidies is an important factor affecting access to denture restoration for the elderly. This study aims to explore access to denture restoration services in the elderly removable denture’s subsidy program of  Taiwan.

Methods

Access to the elderly removable dentures subsidy program was measured from two aspects, that is, availability of subsidies and payment for these services and the characteristics of patients and their treatment needs. The first aspect included reimbursements and the number and location of subsidy clinics, and the second aspect included the age and gender distribution of patients and denture types. Information on reimbursement regulations and the number and location of dental clinics providing subsidized services were obtained from the website of the Taoyuan City Public Health Bureau, Taoyuan Hospital, Department of Statistics and Ministry of Health and Welfare. Data on patient characteristics and denture type were obtained through a retrospective survey. We selected individuals who participated in the elderly removable denture’s subsidy program from 2015 to 2018 at the Geriatric Dentistry Department of Taoyuan Hospital. We conducted data analysis using an interpretive approach.

Results

This study found that reimbursement amounts are inadequate, and the availability of subsidized services is low. Moreover, the proportion of male applications is slightly higher than that of females. In addition, among the applicants, removable partial dentures for single or two arches are the most common.

Conclusions

Problems of insufficient numbers of contracted hospitals and low reimbursement amounts are observed in the subsidy program, which are the key factors affecting access to denture restoration services among the elderly. Policymakers should exclude wealthy individuals and offer subsidy only to low-income elderly individuals with missing teeth who are in dire need of financial support to improve their dental health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-022-07504-6.

What is the evidence on the added value of implant-supported overdentures? A review

Background

Implant‐supported overdentures (IODs) have been reported to increase patients' oral health‐related quality of life (OHRQoL) in comparison with conventional dentures (CDs); however, the conclusiveness of evidence on the clinical effectiveness and value for money of IODs versus CDs remains unclear.

Purpose

To review how the added value of IODs is demonstrated in the literature.

Materials and methods

MEDLINE, EMBASE, and the Cochrane Database were searched for randomized control trials, controlled clinical trials, and prospective cohort studies containing evaluations of the economic and health benefits and costs of IODs. Information about the clinical effectiveness, such as magnitude of bite forces or chewing efficacy, OHRQoL, costs, and cost‐effectiveness of IODs, was extracted.

Results

A total of 17 articles were included, reporting 15 economic evaluations: 11 cost‐utility analyses (CUAs), 2 of which were combined with a cost‐effectiveness analysis (CEA), and 2 cost–benefit analyses (CBAs). Seven CUAs used the Oral Health Impact Profile (OHIP) questionnaire while four used satisfaction questionnaires to assess the OHRQoL. One study applied quality‐adjusted prosthesis years (QAPYs) for this purpose. The CBAs expressed both the beneficial outcome and the costs of the IOD in monetary terms. The included studies employed a large variety of economic evaluation methods, which limited cross‐study comparability.

Conclusions

On the basis of existing economic evaluations, IODs have frequently been suggested to be a cost‐efficient treatment alternative to CDs; however, the comparability between the various economic evaluation studies was limited due to the different outcome measures used. In addition, it remains unclear whether the additional health benefits of IODs outweigh the higher costs. This is largely dependent on the decision maker's valuation of oral health outcomes. Future research is encouraged to further elucidate patient willingness to pay for IODs and the societal return on investing in IODs more generally.

General health status of Dutch elderly receiving implant-retained overdentures: A 9-year big data cross-sectional study

Background

Very little information is available on the general health of elderly who are provided with an implant‐retained overdenture (IOD).

Purpose

The general health status of three groups of elderly (≥75 years) were compared: those with a natural dentition (ND), those treated with an implant‐retained overdenture (IOD), and those wearing a conventional denture (CD).

Materials and methods

Data on healthcare costs were obtained from records of Dutch health insurers that are collected by Vektis. Data on general health (chronic diseases, medication use, and polypharmacy) were acquired for elderly patients with a ND, an IOD, and a CD in 2009 and 2017. Data on the general health of elderly who received an IOD were also acquired from 2010 through 2016.

Results

On average, the general health of elderly who received an IOD was comparable to general health of elderly with a ND and was better than the general health of elderly with a CD (lower prevalence of diabetes, cardiac disease, and hypertension). The general health profile of elderly receiving an IOD was consistent during all years.

Conclusions

The general health of elderly with a ND or IODs is better than those with CDs.

Cost-effectiveness of three different concepts for the rehabilitation of edentulous mandibles: Overdentures with 1 or 2 implant attachments and hybrid prosthesis on four implants

BACKGROUND

There are scarce data regarding the combined assessment of the costs and effects of implant treatments for edentulous patients when multiple options are available.

AIM

This randomised clinical trial aimed to assess the cost-effectiveness of three different concepts for treatment: mandibular overdenture retained by a single (Group I; n = 11) or two implants (Group II; n = 13) and fixed hybrid prosthesis on four implants (Group III; n = 13).

METHODS

Treatment effectiveness was measured as the 1-year before-after changes in patient satisfaction with the mandibular prosthesis. Costs were prospectively quantified from the perspective of the health provider, including all direct cost items attributed to the delivery of treatments and up to the 1-year follow-up, using a "bottom-up" costing estimation method.

RESULTS

Patient satisfaction after treatment improved significantly for the three groups. The overall costs were R$ 2370.66, R$ 3185.21 and R$ 5739.52 for Groups I, II and III, respectively (P < .001). Analysis of incremental cost-effectiveness ratios suggested that the overdentures retained by one or two implants were more cost-effective than the fixed implant treatment, considering the mean cost and effectiveness values and the ±20% one-way sensitivity analysis.

CONCLUSION

This study suggests that the incremental costs for the fixed hybrid prosthesis, compared to the overdenture treatments, is not proportional to the respective gain in effectiveness. Therefore, although all treatment options had satisfactory outcomes, the use of implants to retain a mandibular overdenture, irrespective of the use of one or two implants, is more cost-effective than the fixed implant treatment for the edentulous mandible.

A questionnaire study on the impact on oral health-related quality of life by conventional rehabilitation of edentulous patient

Purpose

This study aimed to determine whether complete dentures improve the oral health-related quality of life (OHRQoL) of edentulous patients, and to assess any associations related to age, gender, and OHRQoL.

Material and methods

Hundred edentulous patients who required conventional complete denture treatment were selected for this study. The following inclusion criteria were established: edentulous in both jaws with no previous history of denture treatment and no significant medical history. The patients were selected who satisfied the criteria associated with the class I prosthodoctic diagnostic index. OHRQoL of the patients were assessed twice, once pre treatment (at the first visit) and once post treatment (8 weeks post insertion of dentures) using an instrument called OHIP-EDENT-N. Significant differences in the OHIP-EDENT-N scores between pre treatment and post treatment were calculated using the Wilcoxon Signed-Rank test. Gender differences were assessed using the Mann–Whitney test.

Results

After provision of new complete dentures, all domains of the OHIP-EDENT-N showed significant improvements except physical pain and social disability.

Conclusions

The results of this study indicated that conventional complete denture improved the OHRQoL of edentulous patients.

Functional oral health-related quality of life impact: A systematic review in populations with tooth loss

Patients perceive the impact of oral disorder in four major areas, the dimensions of oral health-related quality life (OHRQoL) Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact. The functional aspect is essential given the need of chewing, biting, speech and swallowing. The objective of this study was to identify OHRQoL information for dental subjects with functional oral health problems. In a systematic review, distinct and clinically relevant groups of dental subject samples, in this study called "population groups," with such functional OHRQoL information based on the Oral Health Impact Profile (OHIP) were identified (PROSPERO registration: CRD42017064033). The search strategy was "Oral Health Impact Profile" or OHIP. Searches were conducted in the PubMed interface of the Medline database, EMBASE, Cochrane, CINAHL and PsyINFO on 8 June 2017 and updated on 14 January 2019. Published OHIP domain data of different versions were recalculated into OHIP-14`s Physical Disability domain score, characterising the subject's Oral Function impact. 3,653 potentially abstracts were screened. We identified 78 publications reporting dimensional information on 154 subject samples with 52 populations. A typical mean functional impact for partially dentate subjects was 1.6 units on a 0 to 8 unit metric, while for edentate subjects, the mean functional impact was 2.6 units. The functional impact score ranged from 0 to 7.9 units with 50% of the patient samples located between 0.8 and 2.6 units. For the first time, we provide normalised and therefore comparable metric information about the functional OHRQoL impact for a substantial number of functional oral conditions.

Cost-effectiveness analysis of two attachment systems for mandibular overdenture

Objectives

This study analysed the cost‐effectiveness of two different attachments for the 2‐implant overdenture (2IOD) in edentulous mandibles.

Materials and methods

When considering alternative treatments, cost‐effectiveness analysis is an important factor for stakeholders (patient, clinician, social security, insurance company, etc.). A general practice population (n = 116) was treated between 2003 and 2013 with a mandibular 2IOD with 2 different ball/stud attachment systems, one spherical (Group D) and one cylindrical (Group L). Patient well‐being was assessed with OHIP‐14‐Total (OHIP‐14‐T), at intake and annually up to 5 years, to calculate the health effect. Initial and maintenance costs of both treatments were inventoried. The cost‐effectiveness was compared. Annual discount rates of 4% and 1.5% were applied to future costs and health outcomes, following Dutch guidelines. Prices were adjusted to the year 2003. To offset the uncertainty in relevant input parameters, a sensitivity analysis was performed using bootstrap analysis. Significance was set at p < .05.

Results

The health effect was 6.36 (SD 5.32) for Group D and 8.54 (SD 5.63) for Group L. The sum of the discounted costs up to 5 years was EUR 4,210.98 (SD 634.75) for the D and EUR 3,840.62 (SD 302.63) for the Group L (p = .005). The bootstrapping reports that L abutment clearly dominates the D abutment in terms of cost‐effectiveness.

Conclusions

The 2IOD on the L abutment is dominant compared to the 2IOD on D abutment, in a 5‐year perspective.

A comparison of cost and cost-effectiveness analysis of two- implant-retained overdentures versus other removable prosthodontic treatment options for edentulous mandible: A systematic review

Aim:

The aim of this study was to examine systematically the data published on the cost and cost-effectiveness of mandibular two-implant-retained overdentures compared to other removable prosthodontic treatment options for edentulous mandible.

Settings and Design:

It is a systematic review which analyses the available data from the prospective and retrospective studies and randomized clinical trials to find out costs and cost effectiveness of different removable treatment modalities for completely edentulous mandible. The study protocol was decided according to PRISMA guidelines.

Materials and Methods:

The search was limited to English literature only and included an electronic search through PubMed Central, Cochrane Central Register of Controlled Trials, and complemented by hand-searching. All clinical trials published up to August 2019 were included (without any starting limit). Two independent investigators extracted the data and assessed the studies.

Statistical Analysis Used:

No meta-analysis was conducted because of the high heterogeneity of data.

Results:

Out of the initial 509 records, only nine studies were included. The risks of bias of individual studies were assessed. Six studies presented data on cost and cost analysis only. The rest three articles provided data on cost-effectiveness. The overall costs of implant overdentures were higher than the conventional complete dentures. However, implant overdentures were more cost-effective when compared to conventional complete dentures. Single-implant overdentures are also less expensive than two-implant overdentures. Overdentures supported by two or four mini-implants were also reported as more cost-effective than conventional two-implant-supported overdentures.

Conclusions:

Two-implant-retained overdentures are more expensive but cost-effective than the conventional complete dentures. Two- or four-mini-implant-retained overdentures are less expensive than two-implant-retained overdentures, but there is a lack of long-term data on aftercare cost and survival rate of mini-implants. Single-implant overdentures are also less expensive than the two-implant-retained overdentures. The differences of the aftercare costs of different attachment systems for implant overdentures were not significant. There is a need of further studies on comparative cost-effectiveness of different types of implant overdentures.

A cross sectional study of dental implant service provision in British and Irish dental hospitals

Introduction There are multiple ways in which treatment using dental implants is provided in a secondary care setting, not only in terms of the groups of patients treated, but also the clinicians who provide that care.Methods An online survey was circulated to speciality registrars in restorative dentistry in all UK dental hospitals and to postgraduate students in prosthodontics in the Republic of Ireland, consisting of nine questions aimed at understanding which patient groups are treated using dental implants in a hospital setting, how cases are planned, executed and to explore the underlying reasons for each unit's method of provision.Results Completed surveys were received from 67% of dental hospitals in Britain and Ireland. Treatment planning was undertaken by the restorative team alone in 64% of units in patients with hypodontia, 57% with trauma and 71% with an atrophic edentulous ridge and by a multi-disciplinary team in 50% of units for patients with cleft lip and palate (CLP) and 45% with head and neck (H&N) cancer. The restorative team place all or most of the implant fixtures in 50% of units in patients with CLP, 71% in trauma patients, 71% in hypodontia patients, 64% in edentulous patients and 43% in H&N oncology patients. Stents are produced and used by the restorative team in 64% of units for edentulous patients, 79% of patients with hypodontia, 79% of those suffering trauma, 58% of CLP patients and 50% of patients with H&N cancer. Twenty-one percent of responding units had stents made by the restorative team and used by the surgical team. The median percentage of implant-supported restorations that are screw retained is 90% (SD: 4.93, range: 25-95%) and the median percentage of zirconia abutments being used is 22.5% (SD: 5.24, range: 0-50%). Use of zygomatic implants varies hugely between responding units with 43% of them not placing any zygomatic implants.Conclusions There is a wide range of protocols and team members involved in the provision of dental implant rehabilitations throughout the British Isles reflecting the lack of any single evidence-based approach. A multi-disciplinary team approach with the restorative dentist as a key member is likely to yield the most favourable long term outcomes.

Income or education, which has a stronger association with dental implant use in elderly people in Japan?

OBJECTIVES

Although inequalities in dental implant use based on educational level have been reported, no study has used income as a proxy for the socioeconomic status. We examined: (i) income inequalities in implant use; and (ii) whether income or education has a stronger association with implant use in elder Japanese.

METHODS

In 2016, a self-reported questionnaire was mailed to participants aged 65 years or older living across Japan as part of the ongoing Japan Gerontological Evaluation Study. We used data from 84,718 respondents having 19 or fewer teeth. After multiple imputation, multi-level logistic regression estimated the association of dental implant use with equivalised income level and years of formal education. Confounders were age, sex, and density of dental clinics in the residential area.

RESULTS

3.1% of respondents had dental implants. Percentages of dental implant use among the lowest (≤ 9 years) and highest (≥ 13 years) educational groups were 1.8 and 5.1, respectively, and among the lowest (0 < 12.2 '1,000 USD/year') and highest (≥ 59.4 '1,000 USD/year') income groups were 1.7 and 10.4, respectively. A fully adjusted model revealed that both income and education were independently associated with dental implant use. Odds ratios for implant use in the highest education and income groups were 2.13 [95% CI = 1.94-2.35] and 4.85 [95% CI = 3.78-6.22] compared with the lowest education and income groups, respectively. From a model with standardised variables, income showed slightly stronger association than education.

CONCLUSION

This study reveals a public health problem that even those with the highest education but low income might have limited accessibility to dental implant services.

Oral health-related quality of life and satisfaction of edentulous patients using conventional complete dentures and implant-retained overdentures: An umbrella systematic review

BACKGROUND

Loss of teeth has a negative influence on essential oral functions. It is important to understand edentulous patients' perceptions about the impacts of treatment options on their oral health-related quality of life (OHRQoL) and satisfaction.

AIMS

To appraise the systematic reviews (with/without meta-analysis) that investigate the impacts of complete conventional dentures (CCDs) and/or implant-retained overdentures (IRODs) on the oral health-related quality of life (OHRQoL) and satisfaction among edentulous patients.

METHODS

The Joanna Briggs Institute (JBI) methodology for conduct of an umbrella systematic review was followed. Three database systems were used: Medline, Google Scholar and Cochrane Library. PROSPERO was searched for ongoing or recently completed systematic reviews. The reviews must report OHRQoL and patients' satisfaction as outcomes.

RESULTS

A total of eight reviews were included in data synthesis (six were systematic reviews without meta-analysis, one was systematic review with meta-analysis, and one was meta-analysis). The level of evidence of all included reviews based on the Scottish Intercollegiate Guidelines Network ranged between 1+ and 1-.

CONCLUSION

The results of this umbrella systematic review demonstrate the superiority of using IRODs compared with CCDs on the OHRQoL and patients' satisfaction outcomes. However, this positive impact is more accentuated when patients demand implant treatment or cannot adapt to CCDs treatment. Financial factors and adaptive capability indeed affect patient tolerance to both treatment modalities.

A within-subject clinical trial on the conversion of mandibular two-implant to three-implant overdenture: Patient-centered outcomes and willingness to pay

OBJECTIVES

To examine the impact of adding a third midline implant with stud attachment to a mandibular two-implant overdenture on patient-oriented outcomes.

METHODS

In this pre-post design clinical trial, following the standard procedures, mandibular two-implant overdentures of 17 edentulous individuals (61.9 ± 6.6 years) were converted to three-implant overdentures by adding a stud attachment to an unloaded midline implant. Patient-oriented outcomes included patient expectations and satisfaction with implant overdenture as well as willingness to pay the cost of conversion. Data were collected at baseline and at the 6-week follow-up using visual analog and binary scales as well as open-ended questions. Statistical analysis included descriptive statistics, Spearman's correlation, Fisher exact test, Mann-Whitney U test, and the exact sign test.

RESULTS

After connecting the third midline implant to the mandibular two-implant overdenture, there was a statistically significant decrease in the anteroposterior movement (p = 0.005) as evaluated by clinicians. Moreover, study participants reported an increase in perceived stability of the overdenture (95% CI; 0.68-1.00, p = 0.002) and in their ability to speak (95% CI; 0.63-1.00, p = 0.008). The addition of a third implant met the expectations of 94% of patients in regard to lower denture stability, 100% for retention, and 82.4% for comfort. The mandibular three-implant overdenture increased patient general satisfaction over a short period of time, but this improvement was not statistically significant. About 80% of patients would recommend this type of prosthesis to their peers but only 47% of them would agree to pay a large increase in the cost of treatment compared to a two-implant overdenture.

CONCLUSIONS

The addition of a midline third implant to an existing mandibular two-implant overdenture resulted in several improved patient-reported outcomes.

Success of Complete Denture Treatment, Detailed Investigation of Construction Protocols, Occlusal Schemes and Evaluation Questionnaires

Background/Aim: The successful outcome of conventional complete denture treatment can be defined with the use of both subjective and objective criteria. Denture satisfaction determinants may include denture quality, oral tissue condition, patient-dentist relationship, patient’s attitude toward dentures, patient’s personality and socioeconomic factors. Purpose: The aim of the current review was to identify and analyze the different construction protocols and occlusal schemes that contribute to the success of complete denture rehabilitation through the use of evaluation questionnaires.

Material and Methods: A comprehensive literature search was performed through electronic databases (MEDLINE via PubMed) using the appropriate key words (complete denture construction, complete denture fabrication, complete denture occlusion and complete denture occlusal scheme). The related to the subject scientific papers were selected and evaluated for eligibility utilizing a predefined review process (English, full text articles, published from January 2000 up to April 2017).

Results: None of the analyzed studies identified significant differences between dentures constructed with simplified, CAD/CAM and traditional protocols in terms of general satisfaction and Oral Health Related Quality of Life scales. The same condition applied to the studies which compared complete dentures with bilateral balanced, lingualized, monoplane and canine guided occlusion.

Conclusions: Current scientific evidence suggested that patients could adapt comfortably to any type of bilateral balanced occlusal scheme and to complete dentures been fabricated with all types of complete denture construction protocol. Disease-specific questionnaires could be considered valuable tools and should be used to assess the outcome of any treatment modality.

Are UK graduates equipped with the skill set required to meet the demands of the UK's edentulous population?

As the UK witnesses a decline in the number of edentulous adults, there is a simultaneous reduction in the number of cases available to undergraduate dental students for the teaching of complete dentures. When edentulous adults are unable to function with conventional complete dentures, particularly pertaining to the mandibular denture, an implant-supported mandibular overdenture has been evidenced as the gold standard for edentulous patients. The evidence in favour of mandibular implant-supported overdentures is one of the most robust evidence bases for any clinical treatment and similarly it has been shown that undergraduate students are equally as capable in the provision of implant-supported overdentures as experienced prosthodontists. Yet there appears to be a disparity in the General Dental Council's undergraduate learning outcomes pertaining to care for edentulous adults. Furthermore, the UK seems to be falling behind in this respect in comparison to our European, American and Australian colleagues. This review looks at the evidence for the provision of implant-supported overdentures in the setting of the undergraduate dental curriculum, the potential barriers within this teaching forum and how well prepared UK undergraduates are for the clinical management of edentulous patients in the future.

Technical Quality of Complete Dentures: Influence on Masticatory Efficiency and Quality of Life

PURPOSE

To evaluate the effect of the technical quality of conventional complete dentures (CD) on masticatory efficiency and quality of life (QoL) of denture wearers during a 1-year follow-up.

MATERIALS AND METHODS

A prospective clinical trial with 32 edentulous patients (mean age of 60.2 years) wearing mandibular and maxillary dentures was conducted. All patients were evaluated wearing their preexisting dentures and after 3, 6, and 12 months postinsertion of new dentures. A reproducible method for objective evaluation of the technical quality of CDs was employed. Masticatory efficiency was evaluated by the colorimetric method using beads as artificial testing food. The oral health impact on patient QoL was measured using the OHIP-EDENT (Oral Health Impact Profile in Edentulous Adults) questionnaire. The nonparametric Wilcoxon test was applied to reveal any differences in technical quality between the preexisting and new dentures. The Friedman test was used to detect differences in masticatory efficiency and oral health impact on QoL. Spearman's correlation was applied to reveal correlation between the variables.

RESULTS

Comparing preexisting and new dentures, significant improvement was found in technical quality between the dentures (p < 0.001). There was no statistically significant difference in masticatory efficiency. A significant decrease was found in the total OHIP-EDENT scores after denture replacement. A positive correlation was found between technical quality and OHIP in the new denture wearers (p = 0.011).

CONCLUSIONS

According to the results of this study, denture quality significantly improved patients' oral health-related QoL; however, insertion of new dentures did not influence masticatory efficiency.

Cost-effectiveness analysis of two impression methods for the fabrication of mandibular complete dentures

OBJECTIVES

To compare the cost and to evaluate cost-effectiveness of fabricating mandibular complete dentures (CDs) using two different impression methods.

METHODS

A crossover randomized controlled trial including 27 edentulous participants was performed. Mandibular CDs were fabricated using two different impression methods, as follows: (i) conventional method using a custom tray border moulded with impression compound and silicone and (ii) simplified method using a stock tray and alginate. Cost analysis was performed from a clinical practitioner's perspective. The total cost included labor cost, which was calculated using the time spent by dentists and technicians in fabricating CDs and their hourly wages, and the material costs, which were calculated using purchase prices. To evaluate cost-effectiveness, we used general patient satisfaction as an indicator of effectiveness and calculated the incremental cost effectiveness ratio (ICER). ICER represents the cost per one unit of effectiveness.

RESULTS

The trial was completed by 24 participants. The total cost was 43,904 Japanese Yen (JPY) (330.91 EUR / 395.78 USD) for the conventional method and 39,792 JPY (299.93 EUR / 358.70 USD) for the simplified method, and this difference was statistically significant (p<0.001). The ICER showed a cost of 633 JPY (4.77 EUR / 5.70 USD) for every one point change in general patient satisfaction.

CONCLUSIONS

The results indicated that the total cost of the conventional method was significantly higher than that of the simplified method (p<0.001).

CLINICAL SIGNIFICANCE

The conventional impression method for fabricating mandibular CDs, which took additional 633 JPY (4.77 EUR / 5.70 USD) for improvement of general satisfaction, is supposed to be clinically meaningful¹.

Comparison of implant supported mandibular overdentures and conventional dentures on quality of life: a systematic review and meta-analysis of randomized controlled studies

BACKGROUND

Conventional complete dentures and implant supported overdentures are commonly used by dentists to treat completely edentulous mandibular arches. There have been problems associated with retention and stability while treating completely edentulous mandibular arches compared to maxillary arches. Many factors have been attributed to this, primarily focusing on the decreased area available for support and increased resorption. Implant supported overdentures have increased the treatment options for resorbed ridges, especially the mandible. However, no reports have proved the superiority of one treatment option over the other, especially in terms of patient-centric outcome measures such as the Oral Health Impact Profile (OHIP). Hence, this meta-analysis was conducted.

METHODS

A literature search of Medline (via PubMed), the Cochrane Central Register of Clinical Trials (CENTRAL) and the Database of Abstracts of Reviews of Effects (DARE) was performed. The reviewers screened titles, abstracts and performed full-text screening of eligible studies. The references from these studies were further screened for additional relevant studies. A random effects model was applied to measure the significance of the per cent mean difference in OHIP scale improvement between implant and conventional dentures. The Cochrane Risk of Bias Tool was applied to assess the selection, ascertainment and selective reporting biases.

RESULTS

Five studies were reviewed and identified. Results of 441 patients (228 implant and 213 conventional) were pooled for analysis of primary outcome and other secondary outcomes. A forest plot of total OHIP scores and for secondary outcomes were obtained between the interventions. Results of 441 patients (228 implant and 213 conventional) were pooled for analysis of primary outcome with a mean difference [95% confidence interval] in the score of -30.72[-48.39, -13.05]; mean difference [95% confidence interval] in the score of -26.45[-43.56, -9.35] for functional limitation; -29.16[-60.89, 2.56] for physical pain; -77.61[-154.63, -0.60] for psychological discomfort; -33.70[-47.96, -19.44] for physical disability; -41.17[-55.93, -26.40] for psychological disability; -17.27[-29.44, 5.10] for social disability; and -28.45[-33.97, -22.92] for handicap. A statistically significant difference favouring the implant group was obtained except for physical pain.

CONCLUSIONS

The implant overdenture group performed better in regard to patient satisfaction as measured using the OHIP questionnaire. Further studies are required to identify superiority between the two treatment options.

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.

Clinical guidelines and procedures for provision of mandibular overdentures on 4 mini-dental implants

This article describes the flapless placement of mini-dental implants (MDI) to retain mandibular overdentures. Clinical inclusion/exclusion criteria and clinical protocols for the flapless placement of MDIs and for retrofitting the overdenture are presented. A minimum bone height of 13 mm and a minimal flap are recommended. After drilling, the 4 implants are placed with a self-tapping process. A minimum of 15 Ncm of resistance upon final insertion indicates that immediate loading can be performed. The metal housings with O-rings are incorporated into the prosthesis using autopolymerizing resin. The technique and protocol for immediately loaded 4-mini-implant mandibular overdentures is minimally invasive and cost effective.

Does a mandibular overdenture improve nutrient intake and markers of nutritional status better than conventional complete denture? A systematic review and meta-analysis

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.

Reliability and Validity of a Nepalese Version of the Oral Health Impact Profile for Edentulous Subjects

PURPOSE

To assess the reliability and to validate the translated Nepalese version of the Oral Health Impact Profile (OHIP-EDENT-N) in Nepalese edentulous subjects.

MATERIALS AND METHODS

The international guidelines for translation and cross-cultural adaption of OHIP-EDENT were followed, and a Nepalese version of the questionnaire was adapted for this study. Eighty-eight completely edentulous subjects were then selected for the study and completed their responses for the questionnaire. The reliability of the OHIP-EDENT-N was evaluated using internal consistency. Validity was assessed as construct and convergent validity. Construct validity was determined using exploratory factor analysis (EFA). The correlation between OHIP-EDENT-N subscale scores and the global question was investigated to test the convergent validity.

RESULTS

Cronbach's alpha for the total score of OHIP-EDENT-N was 0.78. Construct validity was assessed by factor analysis: 70.196% of the variance was accountable to five factors extracted from the factor analysis. Factor loadings above 0.40 were noted for all items. In terms of convergent validity, significant correlations could be established between OHIP-EDENT-N and global questions.

CONCLUSIONS

This study has been able to establish the reliability and validity of the OHIP-EDENT-N, and OHIP-EDENT-N can be a considered a reliable tool to assess the oral health related quality of life in the Nepalese edentulous population.

Novel CBCT and optical scanner-based implant treatment planning using a stereolithographic surgical guide: a multipronged diagnostic approach

This report describes the use of the combination of 2 technologies (Cone-beam computed tomography and Optical 3-dimensional scan) to maximize accuracy of implant placement in an area where previous implants failed and had to be removed. This report also stresses the increased efficiency of combining technologies to fabricate stereolithographic surgical guide which, when used intraoperatively, can improve precision of placement.

Cost-effectiveness of implant-supported mandibular removable partial dentures

OBJECTIVES

The aim of this study was to conduct a cost-effectiveness analysis comparing conventional removable partial dentures (RPDs) and implant-supported RPDs (ISRPDs) treatment in patients with an edentulous maxilla and a bilateral free-ending situation in the mandible.

MATERIAL AND METHODS

Thirty subjects were included. A new RPD was made and implant support was provided 3 months later. Treatment costs (opportunity costs and costs based on tariffs) were calculated. Treatment effect was expressed by means of the Dutch Oral Health Impact Profile questionnaire (OHIP-NL49), a chewing ability test (Mixing Ability Index, MAI) and a short-form health survey measuring perceived general health (SF-36), which was subsequently converted into quality-adjusted-life-years (QALYs). The incremental cost-effectiveness ratio (ICER) was the primary outcome measure of cost-effectiveness, comparing both treatment strategies.

RESULTS

The mean total opportunity costs were €981 (95% CI €971-€991) for the RPD treatment and €2.480 (95% CI €2.461-€2.500) for the ISRPD treatment. The total costs derived from the national tariff structure were €850 for the RPD treatment and €2.610 for the ISRPD treatment. The ICER for OHIP-NL49 and MAI using the opportunity costs was €80 and €786, respectively. When using the tariff structure, corresponding ICERs were €94 and €921. The effect of supporting an RPD with implants when expressed in QALYs was negligible; hence an ICER was not determined.

CONCLUSIONS

It is concluded that depending on the choice of outcome measure and monetary threshold, supporting an RPD with implants is cost-effective when payers are willing to pay more than €80 per OHIP point gained. Per MAI point gained, an additional €786 has to be invested.

Systematic Review and Quality Appraisal of Economic Evaluation Publications in Dentistry

Economic evaluation (EE) studies have been undertaken in dentistry since the late 20th century because economic data provide additional information to policy makers to develop guidelines and set future direction for oral health services. The objectives of this study were to assess the methodological quality of EEs in oral health. Electronic searching of Ovid MEDLINE, the Cochrane Library, and the NHS Economic Evaluation Database from 1975 to 2013 were undertaken to identify publications that include costs and outcomes in dentistry. Relevant reference lists were also searched for additional studies. Studies were retrieved and reviewed independently for inclusion by 3 authors. Furthermore, to appraise the EE methods, 1 author applied the Drummond 10-item (13-criteria) checklist tool to each study. Of the 114 publications identified, 79 studies were considered full EE and 35 partial. Twenty-eight studies (30%) were published between the years 2011 and 2013. Sixty-four (53%) studies focused on dental caries prevention or treatment. Median appraisal scores calculated for full and partial EE studies were 11 and 9 out of 13, respectively. Quality assessment scores showed that the quality of partial EE studies published after 2000 significantly improved (P = 0.02) compared to those published before 2000. Significant quality improvement was not found in full EE studies. Common methodological limitations were identified: absence of sensitivity analysis, discounting, and insufficient information on how costs and outcomes were measured and valued. EE studies in dentistry increased over the last 40 y in both quantity and quality, but a number of publications failed to satisfy some components of standard EE research methods, such as sensitivity analysis and discounting.

What constitutes an ideal dental restorative material?

Intense environmental concerns recently have prompted dentistry to evaluate the performance and environmental impact of existing restoration materials. Doing so entices us to explore the 'what if?' innovation in materials science to create more ideal restorative materials. Articulating a specification for our design and evaluation methods is proving to be more complicated than originally anticipated. Challenges exist not only in specifying how the material should be manipulated and perform clinically but also in understanding and incorporating implications of the skill of the operator placing the restoration, economic considerations, expectations patients have for their investment, cost-effectiveness, influences of the health care system on how and for whom restorations are to be placed, and global challenges that limit the types of materials available in different areas of the world. The quandary is to find ways to actively engage multiple stakeholders to agree on priorities and future actions to focus future directions on the creation of more ideal restorative materials that can be available throughout the world.

Two-Year Success Rate of Implant-Retained Mandibular Overdentures by Novice General Dentistry Residents

The purpose of the present study was to evaluate the clinical success and patient satisfaction when dental implant–retained mandibular overdentures are placed and restored by novice general dentistry residents. A total of 50 subjects who were dissatisfied with their mandibular complete dentures were enrolled in the study. Two dental implants were placed in the anterior mandible between the mental foramina by novice general dentistry residents under the direct supervision of the principal investigator. The resident attached the denture to the implants 3 to 4 months later using locator attachments. The implant success rate was determined by measuring bone loss, mobility, pocket probing depth, and gingival and plaque indices. Subjects were asked to complete a satisfaction questionnaire with the prosthesis at 3 months, 1 year, and 2 years after overdenture delivery. A total of 100 implants were placed in the 50 study subjects. Of these, 2 implants were lost in 1 subject, and 1 subject died due to unrelated causes. Of the 48 remaining subjects, 45 have had their implants restored with overdentures. The subjects' overall satisfaction with fit and ability to chew hard foods with their mandibular overdentures improved significantly (P &lt; .05) following the denture attachment to the dental implants. We conclude that novice general dentistry residents can successfully place mandibular implants and restore them with overdentures under direct supervision, subsequently enhancing the subjects' satisfaction with their mandibular dentures.

Patients' expectations, satisfaction, and quality of life with immediate loading protocol

OBJECTIVES

To examine patients' expectations, the level of satisfaction, and the oral health-related quality of life (OHRQoL) with regard to the implants' immediate loading protocol (ILP) in edentate individuals.

METHODS

This pilot trial used a pre-post design to assess patient-centered outcomes in 18 edentate individuals (mean age 62.4 ± 7.7 years) who have received a 2-implant (unsplinted) mandibular overdenture through an ILP. Visual analog scales, the McGill denture satisfaction questionnaire, and the oral health impact profile (OHIP-20) questionnaire were used to evaluate patients' expectations, satisfaction, and OHRQoL at baseline, 2 weeks, 1 month, and 4 months after surgery. Personality trait and socio-demographic information were obtained using the revised NEO personality inventory and a self-administered questionnaire, respectively. Non-parametric methods and Brunner-Langer approach were used to analyze the data.

RESULTS

The participants had a wide range of expectations regarding the ILP. Expectations included short-term positive impact on aesthetics (83.3%) and social life (55.7%), as well as negative effects on comfort (5.6%), the ability to chew (11.1%), and the ability to clean the lower denture (11.1%). The ILP satisfied 94.4% of the participants, regardless of socio-demographic and personality profiles. There was a statistically significant improvement in overall satisfaction, comfort, perceived aesthetics, stability of the overdenture, and ability to chew from baseline to 2-week, 1-, and 4-month follow-up (P < 0.001). There was 100% agreement among patients on recommending this procedure to others. There was a statistically significant decrease in the total OHIP scores and all its domains (P < 0.001) from baseline to 2 weeks. These differences remained statistically significant at 4-month follow-up. The ILP improved patients' OHRQoL, regardless of the implant loss, the socio-demographic characteristics, and personality traits.

CONCLUSIONS

The ILP of two unsplinted implants with a mandibular overdenture significantly improved satisfaction and short-term OHRQoL, and appears to meet expectations in edentulous elders. There was 100% agreement among patients on recommending this procedure to others.

The 'anatomically difficult' denture case

Complete loss of teeth from one or both arches is a disabling condition which is usually managed by a conventional removable denture. Rehabilitation may be poorly tolerated by patients, particularly in the lower jaw, and is more difficult in situations when the anatomy of the denture-bearing area is less favourable. These situations may require specific prosthodontic or surgical techniques, or a combination of both. Prosthodontic solutions involve special impression techniques and the use of soft linings and it is vitally important to manage patient expectations in such cases. This article describes prosthodontic management options for dealing with the fibrous (flabby) anterior ridge and bony exostoses.

CLINICAL RELEVANCE

Although tooth loss in the UK is diminishing, it is nevertheless important that dental practitioners are able to demonstrate good prosthodontic skills for managing an ageing population. Surgical correction of anatomical defects may occasionally be employed.

A randomized trial on simplified and conventional methods for complete denture fabrication: cost analysis

PURPOSE

This study aimed to quantify the costs of complete denture fabrication by a simplified method compared with a conventional protocol.

MATERIALS AND METHODS

A sample of edentulous patients needing conventional maxillary and mandibular complete dentures was randomly divided into group S, which received dentures fabricated by a simplified method, and group C, which received conventionally fabricated dentures. We calculated direct and indirect costs for each participant including unscheduled procedures. This study assessed 19 and 20 participants allocated into groups S and C, respectively, and comparisons between groups were conducted by the Mann-Whitney and Student's t-test (α = 0.05).

RESULTS

Complete denture fabrication demanded median time periods of 173.2 and 284.5 minutes from the operator for groups S and C respectively, and 46.6 and 61.7 minutes from the dental assistant (significant differences, p < 0.05). There was no difference between groups regarding postinsertion adjustments. Group S showed lower values for costs with materials and time spent by patients than group C during the fabrication stage, but not during adjustments.

CONCLUSIONS

The median direct cost of complete denture treatment was 34.9% lower for the simplified method. It can be concluded that the simplified method is less costly for patients and the health system when compared with a conventional protocol for the rehabilitation of edentulous patients.

Are people who still have their natural teeth willing to pay for mandibular two-implant overdentures?

AIM

Oral health in Canada and most developed and developing countries is funded by private payers, whose acceptance of treatment depends on their valuation of it. This study aims to determine how dentate individuals in Quebec, Canada, would value the benefits of mandibular two-implant overdentures based on their willingness to pay (WTP) for the treatment, either directly or with insurance/government coverage.

METHODS

A total of 39 individuals (23-54 years) completed a Web-based WTP survey that consisted of three cost scenarios: (a) out-of-pocket payment; (b) private dental insurance coverage; and (c) public funding through additional taxes. Variations in WTP amounts were measured using regression models.

RESULTS

Among respondents who were dentate or missing some teeth, average WTP out of pocket for implant overdentures was CAD$5419 for a 90% success rate. They were willing to pay an average CAD$169 as one-time payment for private dental insurance, with a one in five chance of becoming edentate. WTP amounts increased substantially with the probability of success of implant overdenture therapy. The results of regression analyses were consistent with theoretical predictions for education level and income (P < 0.05).

CONCLUSIONS

The results of this study, within its limitations, suggest that dentate individuals would be willing to pay a significant amount to receive mandibular two-implant overdentures if and when they become edentate.

A randomised trial of a simplified method for complete denture fabrication: patient perception and quality

Complete denture fabrication involves a series of complex technical procedures. Nevertheless, simplified methods may be as effective as conventional ones albeit the lesser use of time and resources, without disadvantage for the patient. This study compared a simplified method for complete denture fabrication to a conventional protocol in terms of oral health-related quality of life (OHRQoL), patient satisfaction and denture quality. Forty-two edentulous patients requesting treatment with complete dentures were randomly allocated into two study groups. Group S received dentures fabricated by a simplified method and Group C received conventionally fabricated dentures. Before interventions and after three and 6 months following insertion, OHRQoL and patient satisfaction were analysed by specific instruments. A prosthodontist assessed denture quality 3 months after delivery. Groups presented no difference for OHRQoL, denture quality and general satisfaction. Differences regarding patient satisfaction with some aspects of the dentures were found after 3 months (S > C), but were insignificant at 6 months. It was concluded that the simplified method is able to produce dentures of a quality comparable to those produced by the conventional method, influencing OHRQoL and patient satisfaction similarly.

Contemporary issues in the provision of restorative dentistry

This review highlights current issues in the provision of restorative dentistry both in primary and secondary care settings. Current challenges in the provision of restorative procedures are reviewed and methods in improving care and efficiency are proposed. Possible changes to the infrastructure and delivery of care are suggested in order to improve effectiveness and the patient pathway.

SINGLE IMPLANT–RETAINED DENTURES: LOADING OF VARIOUS ATTACHMENT TYPES UNDER OBLIQUE OCCLUSAL FORCES

The primary clinical assessments show that single implant–retained dentures (SIDs) are not worse than two implant–retained dentures (TIDs), although the determination of SID biomechanics is still insufficient. The aim of this work was to determine the loading of commonly used denture attachments that occurs while bearing occlusal forces on SIDs. Finite element method analyses, which took into account the possibility of dentures detaching and sliding on the mucous membrane surface, were used. In the contact calculations conducted, an augmented multiplier Lagrangian method with a classical linear friction model was used. We assumed denture-loading conditions that included oblique mastication forces. The distribution of the occlusal loads between the mucous membrane–bearing area and a denture attachment was examined for economical denture solutions with solitary attachments. Variations in denture movement restrictions among the most typical ball, stud, and axially resilient attachments only insignificantly influenced lateral loads borne by single implantological supports. Axial mobility does not reduce the load on the attachments because mastication loads induce denture settlement that is oblique to the implant axis. The assumption of denture loading with vertical forces leads to a serious underestimation of the loads on implantological supports.