Immediate repair of bony defects in the posterior mandibular region following removal of a fractured implant: a feasible treatment?

The aim of this study was to assess whether immediate bone reconstruction after removal of a fractured dental implant in the posterior mandible provides a sound base for implant replacement, with a favourable treatment outcome and high patient satisfaction. Eight consecutive patients with a fractured implant neck were included. The implant was removed via osteotomy, following which the site was immediately repaired with a mixture of autogenous bone and bone substitute. After a 4-month healing period, sufficient bone and favourable soft tissue conditions were present, allowing implant placement with adequate primary stability. After a further 3 months, the implants were restored with an all-ceramic restoration. Patient satisfaction, the aesthetic outcome, complications, and postoperative morbidity were assessed using standardized clinical and radiographic examinations up to 5 years after crown placement. No implant failures were observed during the follow-up. Plaque accumulation, the presence of calculus, bleeding tendency, and peri-implant inflammation indices were low, indicating healthy peri-implant conditions. The mean marginal bone level change at the 5-year follow-up was - 0.17 ± 0.46 mm. All patients reported a high level of satisfaction (mean overall score 9.3 ± 0.5). In conclusion, immediate reconstruction of the hard tissue after removal of a fractured dental implant is a viable treatment option. This approach facilitates rehabilitation, reduces morbidity, and leads to favourable aesthetic outcomes.

[Ceramic implants: the state of art]

A multitude of biomaterials have been used for the production of implants through the years. Titanium or titanium alloy have been regarded as the 'gold standard' for years. However, potential risks and disadvantages regarding biocompatibility and aesthetics have also been reported for the use of titanium in dental implantology. As such, there is need for an alternative material. Zirconia may be regarded as a possible alternative. It is a ceramic with high fracture toughness and other positive qualities, such as beings metal-free, biocompatible, and white, which is aesthetically desirable. Short-term study results of contemporary zirconia implants are promising and comparable to titanium implants. Nevertheless, the material is relatively brittle and susceptible to surface defects. However, no long-term clinical results exists and possible complications are unknown. Long-term clinical research is needed before zirconia implants routine use may be endorsed.

Dental implant placement in alveolar cleft patients: a retrospective comparative study on clinical and aesthetic outcomes

The aim of this retrospective study was to assess the clinical and aesthetic outcomes, and patient satisfaction, following dental implant therapy in cleft patients. Implant survival, changes in marginal bone level, pocket probing depths, plaque and bleeding indices, aesthetics, and patient satisfaction were assessed in 17 alveolar cleft patients and 17 matched controls. At follow-up (mean 72.4±46.4 months), one implant had been lost in the cleft group. Mean marginal bone loss at follow-up was -0.4±0.4mm in cleft patients and -0.2±0.4mm in controls. Aesthetics of the peri-implant soft tissues (pink aesthetic score) were less favourable (P=0.025) in cleft patients (5.0±1.9) than in controls (6.5±1.7), while peri-implant parameters were comparable in the two groups. Overall patient satisfaction was 8.6±0.9 in cleft patients and 8.9±1.1 in controls (P=0.331). In cleft patients, no difference in aesthetics was observed between patients who received additional bone augmentation at 3 months prior to implant placement and those who did not (P=0.092). Dental implant therapy in cleft patients is associated with high implant survival, minor marginal bone loss, healthy peri-implant soft tissues, and high patient satisfaction. Only the aesthetics of the soft tissues was worse in cleft patients compared to augmented non-cleft patients.

Health and quality of life differ between community living older people with and without remaining teeth who recently received formal home care: a cross sectional study

Objective

To assess oral health, health, and quality of life (QoL) of care-dependent community-living older people with and without remaining teeth who recently received formal home care.

Materials and methods

For this cross-sectional observational study, community-living older people (≥ 65 years), who recently (< 6 months) received formal home care, were interviewed with validated questionnaires and underwent an oral examination. Oral health, general health, medicines usage, frailty (Groningen Frailty Indicator), cognition (Minimal Mental State Examination), QoL (RAND 36), and oral health-related QoL (Oral Health Impact Profile-14) were assessed.

Results

One hundred three out of 275 consecutive eligible older people (median age 79 [IQR (Inter Quartile Range) 72–85 years] participated in the study. Thirty-nine patients had remaining teeth and 64 were edentulous. Compared with edentulous older people, older people with remaining teeth scored significantly better on frailty, QoL, physical functioning, and general health. No significant differences were seen in cognition. Dental and periodontal problems were seen in more than half of the patients with remaining teeth. Two third of the edentulous patients did not visit their dentist regularly or at all.

Conclusions

Care-dependent home-dwelling older people with remaining teeth generally were less frail, scored better on physical functioning and general health and had better QoL than edentulous older people. Dental and periodontal problems were seen in approximately 50% of the elderly.

Clinical relevance

Notwithstanding their common dental problems, frailty, health, and QoL are better in home-dwelling older people with remaining teeth. To maintain this status, we advise not only dentists, but also health care workers and governments, to encourage people to maintain good oral health.

A systematic review and meta-analysis of 3-unit fixed dental prostheses: Are the results of 2 abutment implants comparable to the results of 2 abutment teeth?

The purpose of the systematic review and meta-analysis was to compare the performance of 3-unit bridges on teeth with 3-unit bridges on implants, evaluating survival of the bridges, survival of the teeth or implants, condition of the hard and soft tissues surrounding the supports, complications and patient-reported outcome measures (PROM) after a mean observation period of at least 1 year. A literature search was conducted using a combination of the search terms: fixed partial denture and fixed dental prostheses (FDPs). An electronic search for data published until January 2017 was undertaken using the MEDLINE, EMBASE and Cochrane Library databases. Eligibility criteria included clinical human studies, either randomised or not, interventional or observational, which evaluated the results of 3-unit FDPs on either 2 implants or 2 abutment teeth. The search identified 1686 unique references. After applying eligibility criteria, 66 articles were included in the analysis. A total of 1973 3-unit FDPs were supported by teeth, and 765 were implant-supported. No significant differences were found either in the survival of the supporting abutments (P = .52; 99% vs 98.7% survival per year) or in the survival of the prostheses (P = .34; 96.4% vs 97.4% survival per year). Both treatments show an almost equally low complication rate, but there is a low level of reporting of hard and soft tissue conditions and PROM. It is concluded that implant-supported 3-unit FDPs seem to be a reliable treatment with survival rates not significantly different from the results of teeth-supported 3-unit FDPs.

Maxillary implant-supported overdentures opposed by (partial) natural dentitions: a 5-year prospective case series study

The aim of this study was to assess the 5-year treatment outcome of maxillary implant-retained overdentures opposed by natural antagonistic teeth. Fifty consecutive patients received maxillary overdentures supported by six dental implants. Implants were placed in the anterior region, if enough bone was present (n = 25 patients) Implant were placed in the posterior region if implant placement in the anterior region was not possible (n = 25 patients). Variables assessed included survival of implants, condition of hard and soft peri-implant tissues and patients' satisfaction. The five-year implant survival rate was 97·0% and 99·3%, and mean radiographic bone loss was 0·23 and 0·69 mm in the anterior and posterior group, respectively. Median scores for plaque, calculus, gingiva, bleeding and mean scores for pocket probing depth were low and stayed low. Patients' satisfaction after treatment was high in both groups. Within the limits of this 5-year study, it is concluded that six dental implants (placed in the anterior or posterior region) connected with a bar and opposed to natural antagonistic teeth result in acceptable results for clinical parameters and good outcomes for marginal bone level changes and patient satisfaction.

Implantology and the Severely Resorbed Edentulous Mandible

Patients with a severely resorbed edentulous mandible often suffer from problems with the lower denture. These problems include: insufficient retention of the lower denture, intolerance to loading by the mucosa, pain, difficulties with eating and speech, loss of soft-tissue support, and altered facial appearance. These problems are a challenge for the prosthodontist and surgeon. Dental implants have been shown to provide a reliable basis for fixed and removable prostheses. This has resulted in a drastic change in the treatment concepts for management of the severely resorbed edentulous mandible. Reconstructive, pre-prosthetic surgery has changed from surgery aimed to provide a sufficient osseous and mucosal support for a conventional denture into surgery aimed to provide a sufficient bone volume enabling implants to be placed at the most optimal positions from a prosthetic point of view. The aim of this paper is to review critically the literature on procedures related to the severely resorbed edentulous mandible and dental implant treatment. The study includes the transmandibular implant, (short) endosseous implants, and reconstructive procedures such as distraction osteogenesis, augmentation of the mandibular ridge with autogenous bone, and bone substitutes followed by the placement of implants. The number of patients participating in a study, the follow-up period, the design of the study, the degree of mandibular resorption, and the survival rate of the dental implants all are considered evaluation parameters. Although numerous studies have described the outcome results of dental implants in the edentulous mandible, there have been few prospective studies designed as randomized clinical trials that compare different treatment modalities to restore the severely resorbed mandible. Therefore, it is not yet possible to select an evidence-based treatment modality. Future research has to be focused on long-term, detailed follow-up clinical trials before scientificaly based decisions in treating these patients can be made. This will contribute to a higher level of care in this field.

Does a large dehiscent implant surface at placement affect the 5-year treatment outcome? An assessment of implants placed to support a maxillary overdenture

The aim of this study was to assess the 5-year clinical and radiographic outcome of implants with a dehiscent surface at implant placement. A total of 26 consecutive patients (mean age 61.6 years; SD 8.0 years) with at least one implant with a dehiscent implant surface of ≥ two thirds of the implant length on the labial side were included. All implants were placed to support a maxillary overdenture. The implants were placed with adequate primary stability and the dehiscent surface was covered with autologous bone, inorganic bovine bone and a resorbable membrane. Outcome measures were soft tissue conditions, change of radiographic marginal bone level and implant survival. Baseline data (at loading, T0) were compared with 1-year (T1) and 5-year (T5) post loading data. Of the 116 implants, 40 implants had no dehiscence, 16 had a buccal dehiscence < two thirds of the implant length, and 60 implants had a dehiscence ≥ two thirds. The peri-implant tissues were healthy and 5-year marginal bone changes were well within normal limits (-0.4 mm; range: -0.8 to -0.1). One implant was lost during the osseointegration period. Even when implants are placed with a dehiscence ≥ two thirds of the buccal implant surface, favorable 5-year peri-implant health can be achieved provided these dehiscences are covered with autologous bone, inorganic bone and a resorbable membrane, and there is good initial stability of the implants.

[Oral health in care-dependent elderly: an inventory in a nursing home in the north of the Netherlands]

When people grow old and dependent on care, it usually becomes increasingly difficult to maintain oral health. The aim of this study was to assess what changes have taken place during the last ten years in oral health and the need for dental care among patients who were admitted to a nursing home between 2002 and 2012. Results revealed that the number of patients with remaining teeth increased significantly, from 7.9% to 28.7%, and that the number of patients with implants increased from 0.0% to 3.2%. More than 80% of the patients had moderate to poor oral health upon arrival. Moreover, almost half of the patients were revealed to be non-cooperative for evaluation and/or treatment, especially those who had remaining teeth. The expectation is that as a result of the increasing number of care-dependent elderly with remaining teeth in combination with poor oral health, the demand for dental care for care-dependent elderly in nursing homes will increase harply in the coming years.

Improving masticatory performance, bite force, nutritional state and patient's satisfaction with implant overdentures: a systematic review of the literature

Oral function with removable dentures is improved when dental implants are used for support. A variety of methods is used to measure change in masticatory performance, bite force, patient's satisfaction and nutritional state. A systematic review describing the outcome of the various methods to assess patients' appreciation has not been reported. The objective is to systematically review the literature on the possible methods to measure change in masticatory performance, bite force, patient's satisfaction and nutritional state of patients with removable dentures and to describe the outcome of these. Medline, Embase and The Cochrane Central Register of Controlled Trials were searched (last search July 1, 2014). The search was completed by hand to identify eligible studies. Two reviewers independently assessed the articles. Articles should be written in English. Study design should be prospective. The outcome should be any assessment of function/satisfaction before and at least 1 year after treatment. Study population should consist of fully edentulous subjects. Treatment should be placement of any kind of root-form implant(s) to support a mandibular and/or maxillary overdenture. Fifty-three of 920 found articles fulfilled the inclusion criteria. A variety of methods was used to measure oral function; mostly follow-up was 1 year. Most studies included mandibular overdentures, three studies included maxillary overdentures. Implant-supported dentures were accompanied by high patient's satisfaction with regard to denture comfort, but this high satisfaction was not always accompanied by improvement in general quality of life (QoL) and/or health-related QoL. Bite force improved, masseter thickness increased and muscle activity in rest decreased. Patients could chew better and eat more tough foods. No changes were seen in dietary intake, BMI and blood markers. Improvements reported after 1 year apparently decreased slightly with time, at least on the long run. Treating complete denture wearers with implants to support their denture improves their chewing efficiency, increases maximum bite force and clearly improves satisfaction. The effect on QoL is uncertain, and there is no effect on nutritional state.

Maxillary sinus floor elevation surgery with BioOss® mixed with a bone marrow concentrate or autogenous bone: test of principle on implant survival and clinical performance

The purpose of this study was to assess implant survival and 1-year clinical performance of implants placed in the posterior maxilla that had been subjected to maxillary sinus floor elevation surgery with bovine bone mineral (BioOss®) mixed with autogenous bone marrow concentrate or autogenous bone. In a randomized, controlled, split-mouth design study, a bilateral sinus floor augmentation procedure was performed in 12 edentulous patients. At random, one side was treated with BioOss® seeded with an iliac crest bone marrow concentrate enriched in mesenchymal stem cells (test side) and the other with BioOss® mixed with autogenous bone (control side). Three to four months after augmentation, 66 implants were placed. Implant survival, plaque, gingival, and bleeding indices, probing depth, and peri-implant radiographic bone levels were assessed at baseline and 12 months after functional loading. During osseointegration, three implants failed on the test side (two patients) and no implants failed on the control side, resulting in 3-month survival rates of 91% and 100%, respectively. No implants were lost after functional loading and no differences in soft tissue parameters or peri-implant bone loss were observed between the control and test sides. After 1 year in function, no clinically relevant differences were observed regarding soft tissue parameters or peri-implant bone loss.

[Treatment of a single-tooth space in the occlusal system]

The space created by the absence of 1 not-free-ending tooth in an occlusal system can be indicated as a single-tooth space. For treating a single-tooth space, several options are available to restore the functions of the occlusal system. Feasible options are a resin-bonded fixed prosthesis, a conventional fixed prosthesis, and an implant-supported restoration. Implant-supported restorations have a good prognosis, high patient satisfaction, and the advantage that adjacent teeth are not involved in the treatment. Anxiety about surgical treatment, the width of the single-tooth space, and financial aspects may be reasons not to consider an implant-supported restoration as first-choice treatment.

Maxillary sinus lift with solely autogenous bone compared to a combination of autogenous bone and growth factors or (solely) bone substitutes. A systematic review

Literature regarding the outcome of maxillary sinus floor elevation to create sufficient bone fraction to enable implant placement was systematically reviewed. Bone fraction and implant survival rate were assessed to determine whether grafting material or applied growth factor affected bone fraction. Trials where sinus floor elevations with autogenous bone (controls) were compared with autogenous bone combined with growth factors or bone substitutes, or solely with bone substitutes (test groups) were identified; 12 of 1124 fulfilled all inclusion criteria. Meta-analyses comparing the bone fraction after applying: autogenous bone; autologous bone with growth factors (platelet rich plasma); or autogenous bone and bone substitutes (bovine hydroxyapatite, bioactive glass, corticocancellous pig bone) revealed no significant differences in bone formation after 5 months. A significantly higher bone fraction was found in the autogenous bone group compared to the sole use of β-tricalciumphosphate (P=0.036). The one-year overall implant survival rate showed no significant difference between implants. Bone substitutes combined with autogenous bone provide a reliable alternative for autogenous bone as sole grafting material to reconstruct maxillary sinus bony deficiencies, for supporting dental implants after 5 months. Adding growth factors (platelet rich plasma) to grafting material and the sole use of β-tricalciumphosphate did not promote bone formation.

[An implant-supported overdenture in an edentulous upper jaw]

An implant-supported overdenture is a good alternative treatment to a conventional denture for patients with complaints about the retention and stability of their removable complete denture. These complaints more often have to do with the mandibular than the maxillary denture. Implant-supported overdentures offer better results in the mandible than in the maxilla. In cases of insujficient bone volume in the maxilla for inserting implants, maxillary sinus floor elevation using an autogenous bone graft from the oral cavity or the iliac crest may be carried out. Treatment of the edentulous maxilla by inserting 6 implants followed by manufacturing a bar-clip mesostructure and an implant-supported overdenture is the most successful, followed closely by the treatment option of inserting 4 implants and fabricating a similar mesostructure and overdenture. Aftercare by routine preventive examinations is required.

[Complications in patients with oral implants. Recommendations for routine preventive inspections]

Oral implantology is a very fast growing and dynamic area of oral healthcare, carried out by an increasing number of oral healthcare providers. Recommendations for routine preventive inspections are needed to control and monitor the quality of treatment. Routine preventive inspection can be divided into inspection of the peri-implant hard and soft tissues and inspection of the prosthetic construction. The most frequently occurring complications, each with its own treatment, are peri-implant mucositis, peri-implantitis, recession of peri-implant tissues, the loosening or fracturing of overdenture attachment components, deterioration of the fit of overdentures, and the loosening of the screw with which a crown is secured on an implant or implant abutment. Carrying out routine preventive inspections will make it possible to detect and treat complications in a timely fashion.

[Risks and liability in complications with respect to implant-supported suprastructures]

Despite high survival percentages of oral implants and suprastructures, various risks threaten the success of oral implant treatments. Four risk categories can be distinguished: complications during surgical treatment, loss or impending loss of the implant, fracture or wearing out of (parts of) the suprastructure, and patient dissatisfaction with the treatment outcome. The question is when a complication can be expected on the basis of present-day knowledge in a certain percentage of cases and when one can speak of negligence. In cases where treatment is carried out in accordance with the most recent protocols, guidelines and recommendations, there can be no question of liability. It is proposed that retreatment is carried out without any costs if an implant or a superstructure is lost within one year post-treatment.

[Prosthetic dilemmas. Choice of superstructure for the edentulous maxilla]

Patients with an edentulous maxilla can experience problems with a full upper denture. The most common problems are a lack of retention and the stability of the denture, but also other factors, such as an extreme gagging reflex, influence satisfaction. Attachment of a prosthesis on dental implants is a reliable solution to solve or diminish the above mentioned problems. The choice of the kind of superstructure, a removable overdenture or a fixed prosthesis, depends on a variety of factors, such as degree of resorption of the maxilla, cleaning possibilities, patients'wishes and financial possibilities

[Recommendations in oral implantology]

Oral implantology is a fast growing and dynamic specialization. An increasing number of dental professionals are carrying out oral implant treatments. Recommendations for oral implant treatments are needed to improve and manage treatment quality. In this article recommendations are proposed for 4 oral implant and superstructure indications in patients without complicating factors. The 4 oral implant indications are a mandibular complete overdenture, a maxillary complete overdenture, a single crown in the maxillary aesthetic region, and crowns and fixed partial dentures in the non-aesthetic region. The recommendations are also related to diagnostics and aftercare.

Bone quality at the implant site after reconstruction of a local defect of the maxillary anterior ridge with chin bone or deproteinised cancellous bovine bone

The purpose of this study was to investigate the quality of bone at grafted implant sites in the anterior maxilla. Grafting of these sites was necessary because of insufficient bone volume in a buccopalatinal direction (width at the top of the crest 1-3mm). Reconstruction was performed with chin bone (N=5), chin bone and a resorbable Bio-Gide GBR membrane (N=5) or Bio-Oss spongiosa granules in combination with a Bio-Gide GBR membrane (N=5). Biopsies were taken prior to implantation, i.e. 3 months after grafting with chin bone, and 6 months after grafting with Bio-Oss. Evaluation was done by assessing the histological and histomorphometric characteristics of full-length biopsies taken from the actual implant site. Both areas with non-vital bone and areas with apposition of bone and remodelling phenomena were observed in the chin bone group at the time of placement of the implants. Similar results were observed at implant sites reconstructed with a chin bone graft covered by a membrane. In the chin bone group without and with a GBR membrane, the mean total bone volume (TBV) was 55.2+/-6.8% and 57.7+/-11.5%, respectively; the marrow connective tissue volume (MCTV) was 44.8+/-6.8% and 42.3+/-11.5%, respectively. Remnants of the resorbable GBR membrane were not detected. In the Bio-Oss((R)) group, at implant placement some newly formed bone was observed in the connective tissue surrounding the Bio-Oss((R)) particles (mean TBV (newly formed bone) 17.6+/-14.5%), but most particles were surrounded by connective tissue. No convincing signs of remodelling were observed (mean remaining Bio-Oss volume 40.5+/-9.3%; mean MCTV 41.9+/-13.1%). No implants were lost during follow up (12 months). At the time of placement of the implants the grafting material (either chin bone or Bio-Oss is still not fully replaced by new vital bone. In case of Bio-Oss, most of the grafting material is even still present. Despite these differences, the 1-year clinical results were very good and comparable between the various grafting techniques applied.

[Oligodontia: treatment plan and therapy]

The aim of this retrospective study was to gain insight in treatment planning and therapy for patients with oligodontia. Records of 58 treated patients with oligodontia were screened using several parameters: gender, year and age of registration, symptoms, case history, treatment plan and therapy. Treatment plans were sorted into the following categories: tooth-supported overdentures, fixed or removable partial dentures and implant-supported restorations. Dependent on the complexity of oligodontia, it is advocated to make a treatment plan before the age of 12 years old and to follow the provided treatment conscientiously until the final prosthetic treatment. After analyzing the 58 treatment plans, the following conclusions could be made: the treatment plan was not in all cases made before the age of 12 years, it was not clear in all cases who was the coordinator of the treatment and dental implants are becoming more and more important in treating patients with oligodontia.

Masticatory function in patients with an extremely resorbed mandible restored with mandibular implant-retained overdentures: comparison of three types of treatment protocols

The objective of the present study was to analyse the effects of implant supported overdentures on masticatory function in patients with an extremely resorbed mandible, and to compare the masticatory function in these patients using three differing types of implant treatment protocols. The mandibular overdentures were retained by a transmandibular implant, by four endosseous implants following augmentation of the mandible, and by four short endosseous implants, respectively. Sixty patients (50 women, 10 men, mean age 59.4 years) were randomly allocated to one of the three treatment groups. Masticatory function was assessed before and after treatment using a questionnaire, a masticatory performance test, and a structured interview. The patient-based masticatory function improved significantly. Concerning these parameters there were no significant differences between the three groups before and after treatment. A significant difference existed between the three groups for the laboratory-assessed masticatory function before treatment, but after treatment this difference was no longer significant. From this study it can be concluded that patients with an extremely resorbed mandible and functional complaints of their lower denture report significant improvement in masticatory function after implant-overdenture treatment. Differences in masticatory function between the three studied modalities were not significant after treatment.

[Implant-retained overdentures compared with complete dentures with or without preprosthetic surgery. A prospective study followed over 10 years]

The aim of this prospective randomized clinical trial was to evaluate and compare a set of clinical items and satisfaction of a group of edentulous patients during a ten-year follow-up. They were treated according to one of the following modalities: 61 patients with a mandibular overdenture on two implants (IMP-group), 60 patients with conventional complete dentures (VP-group) and 28 patients with a complete denture after preprosthetic surgery (MVP-group). It can be concluded that enosseous implants, serving as retention for a mandibular overdenture, have a high survival rate after ten years of follow-up (93%). The mean satisfaction score of the VP-group was lower than that of the IMP-group. The mean satisfaction score of the MVP-group was lower than that of the IMP-group.

[Acceptance and results of electronic implantology instruction]

Aim of this study is the evaluation of a 3-weeks course on dental implants presented in a computer assisted learning program. Evaluation variables are study result, student satisfaction and the use of the program. Fourth grade dental students were divided in a group who received traditional education and a group who received the course by means of an interactive computerprogram. At the end of the experiment there is no difference in study result between the two groups. Students say that the computer assisted learning program is a useful tool in studying the course, but use the program more as a device to obtain information than as a tool to have interactive discussion.

A randomized prospective clinical trial on the effectiveness of three treatment modalities for patients with lower denture problems. A 10 year follow-up study on patient satisfaction

Treatment of lower denture complaints of patients with an edentulous mandible with a height of at least 15 mm can consist of meticulous construction of a new set of dentures (CD), construction of a new set of dentures following preprosthetic surgery to enlarge the denture-bearing area (PPS), or construction of an implant-retained mandibular overdenture (IRO). The aim of this prospective randomized controlled clinical trial was to evaluate the satisfaction of the above mentioned treatment modalities in resolving lower denture related complaints. Ninety edentulous patients (Cawood class IV and V, mean mandibular height 20.7 +/- 2.7 mm) were randomly assigned to one of these treatment modalities. The main outcome parameters were denture satisfaction and chewing ability, which were assessed using validated self-administered questionnaires focusing on denture-related complaints and problems with chewing different types of food. These parameters were measured before treatment, and 1, 5 and 10 years after treatment. Differences among the three groups were tested by applying a one way analysis of variance and a Tukey's test for multiple comparison. At the 1 year evaluation, significantly better scores were observed in the two surgical groups (IRO, PPS) than in the CD group (P<0.05). At 5 year evaluation the 'complaints of the lower denture' showed a significantly better score in the IRO group when compared to the PPS and CD groups (P<0.05). No significant differences were observed between the PPS and CD group. At 10 year evaluation, the intention to treat analysis revealed no significant differences between the three groups, while a per protocol analysis showed that the IRO group was the most satisfied. From this study it is concluded that both on the short and long term denture satisfaction appears most favourable in the IRO group when compared to the PPS and CD groups. Implant-retained overdentures are, therefore, a favourable treatment modality for edentulous patients with lower denture problems.

[Implant-retained overdentures compared with complete dentures with or without preprosthetic surgery. Satisfaction and subjective chewing capabilities]

The aim of this prospective randomized clinical trial was to evaluate and compare a set of clinical items and satisfaction of a group of edentulous patients during a 5-year follow-up. They were treated according to one of the following modalities: 61 patients with a mandibular overdenture on two implants (IMP-group), 60 patients with a conventional complete denture (VP-group) and 28 patients with a complete denture after preprosthetic surgery (MVP-group). It can be concluded that endosseous implants, serving as retention for a mandibular overdenture, have a high survival rate after 5 years of follow-up (93%). The mean satisfaction score of the VP-group was lower than of the IMP-group. The mean satisfaction score of the MVP-group is lower than of the IMP-group.

[Design of custom-shaped abutments for single-tooth crowns on implants]

Single-tooth implants have become a predictable treatment option. Acceptable esthetics are an important factor for success. The emergence profile of the crown in the cervical region is complicated by the discrepancy between the round shape and the small diameter of the implant and the desired anatomical shape of the crown. An abutment on an implant has to provide this natural looking emergence profile and has to support the crown. Custom-shaped abutments are the best option for this task. Many items influence the design. This article discusses a set of guidelines for the design of custom-shaped abutments for single-tooth implants.

Five years of aftercare of implant-retained mandibular overdentures and conventional dentures

The purpose of this multicentre randomized clinical trial was to analyse surgical and prosthetic aftercare and clinical implant performance of edentulous patients with implant-retained mandibular overdentures and of patients with conventional dentures, either or not after pre-prosthetic vestibuloplasty and deepening of the floor of the mouth. The evaluation period was 5 years. The implant systems evaluated were the IMZ implant system, the Brånemark implant system and the Transmandibular Implant system. The centre in Groningen had five groups (n=149) and the centre in Nijmegen had three groups (n=86). The evaluation comprised of surgical and prosthetic aftercare, together with clinical implant performance (CIP). The highest implant loss (29%) is found in the Transmandibular Implant group. All groups had prosthetic revisions and complications according to the CIP-scale. The majority of the patients in the endosseous implant groups were subject to minor complications. The CIP-score of the Transmandibular Implant group is significantly higher than the scores of the other groups, because of the high number of lost posts. In 26;1% of the patients in this group score 4 is given, which means failure of the implant system. From this study it can be concluded that the endosseous implant systems used in this study have less surgical aftercare and a better clinical implant performance than the Transmandibular Implant system and are therefore the systems of choice for the edentulous mandible.