A meta-analysis of implants in partial edentulism

Does the referral and selection for NHS-funded dental implant treatment in the UK follow National Guidelines?

INTRODUCTION

The Royal College of Surgeons of England (RCSE) has provided a national guideline document detailing specific selection criteria for National Health Service (NHS) dental implant therapy in the UK. The aim of this study was to investigate whether these guidelines are being observed both in the referral and selection of patients.

PATIENTS AND METHODS

Information was collected prospectively from 8 consecutive implant assessment clinics at Guy's and St Thomas' Hospital Trust over a 6-month period, via a questionnaire concerning the reason for referral for implant treatment, dental/smoking/radiotherapy status, and the consultant decision on whether an application would be made for NHS implant funding.

RESULTS

Of the 103 referred patients who attended the appointment, 83 (80.6%) fell within the established priority groups for NHS implant therapy: in particular, hypodontia and teeth lost through trauma. However, up to a quarter of patients had untreated caries or periodontitis (n = 23, 22.3% and n = 26, 25.2%, respectively), a contra-indication for NHS implant therapy. The proportion of patients with caries was more than double for general dental practitioner-referred (28.3%) than hospital-referred subjects (12.5%) with the difference approaching statistical significance (P = 0.061). Selection for implant funding application was highly dependent on whether or not a patient belonged to a priority group of the national guidelines (P < 0.001).

CONCLUSIONS

Although in most respects there is good adherence to the RCSE national guidelines both in the referral and selection of patients for NHS implant therapy, about a quarter of patients particularly those referred from general dental practitioners rather than hospitals, would be contra-indicated from NHS therapy because of untreated caries or periodontitis.

Alveolar zygomatic buttress: A new donor site for limited preimplant augmentation procedures

PURPOSE

Augmentation of anterior maxillary alveolar bone defects before placement of endosseous implants still poses a clinical challenge. Previous traumatic loss of upper anterior teeth is often concomitant with significant bone loss. The aim of augmentation is to reconstitute as far as possible the original hard tissue contour. This is a prerequisite for later optimal positioning of the dental implants in accordance with prosthodontic and functional principles.

MATERIALS AND METHODS

This article describes a new method for the reconstruction of small anterior maxillary alveolar bone defects using donor bone from the zygomatic buttress region.

RESULTS

This region provides harvested bone with a natural convex shape, which is ideally suited for the anterior alveolar process region. Later fibrous tissue transplantation to provide more anterior projection to the anterior dental area is also avoided.

CONCLUSION

Bone harvesting was done with the piezoelectric device, which avoids trauma to the mucosal membrane of the maxillary sinus.

Factors that affect individual tooth prognosis and choices in contemporary treatment planning

A clinician evaluates a tooth for its quality of health. Once accomplished an estimate of longevity and survival is estimated. With current knowledge about the survival and success of implants a decision is made as to whether to extract or to treat and maintain the tooth. Questions and doubts abound in the decision making process in regards to the prognosis of an individual tooth. Unfortunately in dentistry, as in all biologic sciences, there are no straightforward answers to questions. This article will attempt to review the literature in this area to aid the practitioner in the decision making process with regards to the compromised tooth. The article will focus on the single tooth or implant restoration. Other factors such as the strategic value of a tooth and financial limitations in relation to long-term prognosis will also be discussed.

Failures in implant dentistry

This article describes the many failures and complications that can occur when using implants to support restorations. Most of these failures can be prevented with proper patient selection and treatment planning. Implant failures can be largely classified into four main categories: 1) loss of integration, 2) positional failures 3) soft tissue defects, and 4) biomechanical failures. Each of these will be discussed with examples to illustrate the problem.

Three-year treatment outcomes with three brands of implants placed in the posterior maxilla and mandible of partially edentulous patients

STATEMENT OF PROBLEM

Survival rates of implants in posterior regions vary among clinical studies. Problems occur more often in the posterior segment of the maxilla due to proximity of the maxillary sinus and reduced quality or quantity of alveolar bone.

PURPOSE

This clinical study evaluated the treatment outcomes of 3 brands of implants in the posterior maxillae and mandibles of 63 patients. Treatment outcomes of all implants were assessed according to implant type, location, patient gender, periodontal status, and prosthesis type.

MATERIAL AND METHODS

A total of 203 implants-105 ITI (ITI), 53 Camlog (CAM), and 45 Frialit (FRI)-were placed in 63 patients (38 women, 25 men). One hundred twelve implants were located in the posterior mandible and 91 in the posterior maxilla. All implants were longer than 10 mm and had a diameter larger than 3.5 mm. Implants in the ITI group were placed in a 1-stage surgery. The CAM and FRI groups were treated with a 2-stage surgical protocol. Implants were not loaded until osseointegration was complete, which was determined clinically and radiographically. At that point, implants were restored with 50 single crowns and 81 fixed partial dentures (FPDs). While 11 FPDs connected implants to natural teeth, 70 FPDs were supported by implants only. Standardized radiographs were made, and clinical parameters were recorded at prosthesis insertion (baseline) and at each recall evaluation (6, 12, 24, and 36 months). Plaque index (PI), sulcus bleeding index (SBI), peri-implant probing depth (PD), and radiographic marginal bone loss (MBL) levels were recorded at baseline, along with any biological and mechanical complications. Repeated-measures ANOVA, Kruskal-Wallis test, Wilcoxon signed rank test, and paired samples tests were used for statistical analysis (alpha=.05).

RESULTS

One implant was lost during the osseointegration period in 1 woman due to infection. The cumulative implant treatment outcome was 99.3%. At the 3-year recall, plaque accumulation was significantly higher than baseline scores (P=.01, Wilcoxon signed rank test). Eight percent of the patients presented>2 mm PD at 2-year recall. The influence of observation time was found to be significant for the mean MBL values between groups (P=.001). When MBL values were compared between groups, no significant differences were found. For 1 patient in the FRI group, abutment loosening was observed and both the crown and the abutment were replaced. Patient satisfaction in all groups was high.

CONCLUSION

The 3 brands of implants evaluated in this study exhibited similar positive treatment outcomes after 3 years.

Prognostic model for tooth survival in patients treated for periodontitis

BACKGROUND

In patients with periodontitis, a quantitative prognostic assessment is needed in order to make evidence-based decisions about retaining teeth or extracting and replacing them with a dental prosthesis.

METHODS

One hundred and ninety eight patients receiving active periodontal treatment in 1989 or 1990 and complying with supportive periodontal therapy (SPT) over an average of 11.8+/-2.3 years were included in the study. A generalized linear model was established and fitted via generalized estimating equations to identify predictors for tooth loss during SPT.

RESULTS

Of the 4559 teeth present at baseline, 166 (3.6%) were extracted during active treatment and 249 (5.5%) during SPT. Baseline findings of diabetes mellitus (OR=4.17), reduced alveolar bone levels (OR=1.04 for each 1% increment), increased tooth mobility (III versus 0: OR=5.52), multiple roots (OR=1.82), and non-vital pulp (OR=2.24) were significant (p<0.05) predictors for tooth loss during SPT. Based on these parameters, a prognostic model was constructed that provides estimates of tooth survival probability when periodontal therapy is rendered.

CONCLUSION

Using a multivariate approach, a prognostic model was developed that may be of value for clinical decision making.

A 5-Year Prospective Study of Single-Tooth Replacements Supported by the Astra Tech® Implant: A Pilot Study

BACKGROUND

Implant-supported single-tooth replacements are an increasingly used method to replace teeth, especially in young patients. Therefore, long-term validation of different treatment modalities with different implant systems is of great importance.

PURPOSE

The aim of the present study was to make a biologic, technical, and aesthetic evaluation of single-tooth replacement supported by the Astra Tech implant (Astra Tech AB, Mölndal, Sweden) during a 5-year period.

MATERIALS AND METHODS

Twenty patients were divided into two consecutively treated groups. In group A the implants were placed "early" in the extraction sockets, and standard single-tooth abutments were used. In group B the implants were placed "delayed," and preparable abutments were used. Clinical examinations including registration of plaque, bleeding, crown lengths, soft tissue marginal level, papilla height, complications, and radiography were performed yearly. At the 3-year control examination the patient and a dentist evaluated aesthetic appearance with a visual analog scale.

RESULTS

An implant survival rate of 100% and a crown survival rate of 95% over a period of 5 years were found. The mean loss of marginal bone adjacent to implants and neighboring teeth was less than 0.5 mm during the 5-year period, and there was no significant difference after crown placement between the treatment modality for group A and that for B. There were fewer clinical complications and repairs in group B than in group A. Soft tissue dimensions were more natural around implant crowns in group B as compared to group A, but this was not reflected in the patients' satisfaction with aesthetic appearance. On the other hand the dentist judged the restorations in group B higher concerning aesthetics than in group A.

CONCLUSION

Implant-supported single-tooth replacement with the Astra Tech system is a reliable treatment resulting in a good 5-year prognosis and only few complications.

The use of a dental implant as an abutment in three unit implant-tooth supported fixed partial denture: a case report and 32 month follow-up

The combined use of dental implants and teeth as abutments in fixed partial dentures may offer advantages to both patients and practitioners in certain clinical situations. An implant-tooth retained prosthesis may reduce surgical intervention and cost to the patient. It may also mean that anatomical restrictions to the provision of an implant-retained fixed prosthesis may be overcome. In this case report, the steps in provision of a three unit implant-to-tooth fixed partial denture are described and the treatment planning and prognosis of a restoration of this type are discussed.

Implants in the esthetic zone

To achieve a successful esthetic result and good patient satisfaction,implant placement in the esthetic zone demands a thorough under-standing of anatomic, biologic, surgical, and prosthetic principles. The ability to achieve harmonious, indistinguishable prosthesis from adjacent natural teeth in the esthetic zone is sometimes challenging. Placement of dental implants in the esthetic zone is a technique-sensitive procedure with little room for error. Guidelines are presented for ideal implant positioning and for a variety of therapeutic modalities that can be implemented for addressing different clinical situations involving replacement of missing teeth in the esthetic zone.

Retrospective Cross Sectional Comparison of Initial Nonsurgical Endodontic Treatment and Single-Tooth Implants

Initial root canal treatment and the replacement of a single tooth with implants are both viable treatment options, but various success rates have been reported for each treatment modality. This study compared 196 implant restorations and 196 matched initial nonsurgical root canal treatment (NSRCT) teeth in patients for four possible outcomes- success, survival, survival with subsequent treatment intervention and failure. Cross classifications/tabulations were analyzed using Pearson's chi(2) test for association of the two classifications (endo vs. implant and outcome). Polytomous regression with likelihood ratio tests were used in testing association with tooth location and outcome. Outcomes were as follows for implants and NSRCT outcomes, respectively: success 73.5% and 82.1%; survival with no intervention 2.6% and 8.2%; survival with intervention 17.9% and 3.6%; and failure 6.1% and 6.1%. Location of the restoration in the mouth did not affect outcome. This study suggests that restored endodontically treated teeth and single-tooth implant restorations have similar failure rates, although the implant group showed a longer average and median time to function and a higher incidence of postoperative complications requiring subsequent treatment intervention.

Endodontic or dental implant therapy

BACKGROUND

Clinicians are confronted with difficult choices regarding whether a tooth with pulpal and/or periapical disease should be saved through endodontic treatment or be extracted and replaced with an implant.

METHODS

The authors examined publications (research, literature reviews and systematic reviews) related to the factors affecting decision making for patients who have oral diseases or traumatic injuries.

RESULTS

The factors to be considered included patient-related issues (systemic and oral health, as well as comfort and treatment perceptions), tooth- and periodontium-related factors (pulpal and periodontal conditions, color characteristics of the teeth, quantity and quality of bone, and soft-tissue anatomy) and treatment-related factors (the potential for procedural complications, required adjunctive procedures and treatment outcomes).

CONCLUSIONS

On the basis of survival rates, it appears that more than 95 percent of dental implants and teeth that have undergone endodontic treatment remain functional over time.

CLINICAL IMPLICATIONS

Clinicians need to consider carefully several factors before choosing whether to perform endodontic therapy or extract a tooth and place an implant. The result should be high levels of comfort, function, longevity and esthetics for patients.

Evidence-based decision-making: implants versus natural teeth

The clinician is increasingly confronted with the dilemma of whether to use implants or so-called "traditional" dental interventions. Given the high predictability of implants, their use should be considered routine. The survival and success rates reported by many investigators often exceed the success rates of some forms of heroic treatment. Findings from well-designed trials must be used to guide clinical decision-making. In this article, the authors review studies of outcomes related to one particular implant system and compare these results to those reported for various forms of endodontic therapy and tissue-supported mandibular complete dentures. The results suggest that implant restorations of the system in question have a level of predictability equal to or greater than that for traditional dental treatment.

Rationale for dental implants

The clinical replacement of lost natural teeth by osseointegrated implants has represented one of the most significant advances in restorative dentistry. Two decades ago, a majority of dentists were sceptical about implants and rejected them entirely. Today it is rare to find a practitioner who does not work with dental implants or who is not actively participating in one of the many seminars or courses offered by universities, professional societies and implant manufacturers.

Immediate Load Protocol for Anterior Maxilla With Cortical Bone From Mandibular Ramus

OBJECTIVE

To evaluate the concept of a nonfunctional immediate load protocol with single implants placed in the anterior maxilla that has been bone grafted with autogenous, block cortical grafts harvested from the ramus of the mandible.

METHODS

There were 19 hydroxyapatite-coated dental implants surgically placed in 19 patients, and immediately loaded between 48 hours and 3 days later with a custom acrylic provisional restoration that was placed out of functional occlusion. After 12 weeks, the definitive ceramo metal restoration was cemented to the custom abutment.

RESULTS

Over a 1-year observation period, all implants continue to function.

CONCLUSION

The preliminary results of this clinical study indicate that immediate, nonfunctional load with single implants is a predictable protocol in the bone grafted anterior maxilla in select cases.

Profilometric and standard error of the mean analysis of rough implant surfaces treated with different instrumentations

PURPOSE

This study evaluated, in vitro, the effects of different instrumentations used in the treatment of peri-implantitis on implant surfaces coated with hydroxyapatite or titanium plasma spray (TPS).

MATERIALS AND METHODS

There were 14 cylindrical rough implants used, including 7 hydroxyapatite and 7 TPS coated. Split in 2 parts for a total of 24 experimental surfaces, implants were treated with a stainless-steel curette, plastic curette, ultrasonic scaler tip, and air-powder-water spray. There was 1 hydroxyapatite and 1 TPS implant used as controls. Profilometry and scanning electron microscopy were used to examine instrumented surfaces for variations in surface topography.

RESULTS

All experimental procedures determined changes on tested rough implant surfaces. Such alterations were related to the implant coating material, and the procedure consisting in coating removal and/or leveling of surface roughness.

CONCLUSION

Although a plastic curette and air-powder-water spray induced less implant surface alterations, these instrumentations left deposits on the surface that may affect, in vivo, the tissue healing process.

Fracture resistance of single-tooth implant-supported all-ceramic restorations: An in vitro study

STATEMENT OF PROBLEM

High-strength ceramic materials can be used to fabricate esthetic and stable implant-supported single-tooth restorations. No study was identified that compared the fracture resistance of individual components of single-tooth implant-supported all-ceramic restorative systems after artificial aging.

PURPOSE

The purpose of this in vitro study was to evaluate the fracture resistance of single-tooth implant-supported all-ceramic restorations consisting of alumina all-ceramic restorations on different implant abutments and to identify the weakest component of the restorative system.

MATERIAL AND METHODS

Forty-eight standardized maxillary central incisor alumina crowns (Procera) were fabricated for each of the 3 test groups (n = 16) (Control group Ti, titanium abutments; Group Al, alumina abutments; Group Zr, zirconia abutments) for the Replace implant system. The crowns were adhesively luted using a resin luting agent (Panavia 21) and artificially aged through dynamic loading and thermal cycling. Afterwards, all specimens were tested for fracture resistance using compressive load on the palatal surfaces of the crowns. Kruskal-Wallis analysis of variance and post hoc Wilcoxon rank sum tests were performed to test for differences in fracture resistance values (alpha = .05).

RESULTS

All test specimens survived the artificial aging process using simulated oral conditions. No screw loosening was recorded. The median fracture resistance was 1454 N, 422.5 N, and 443.6 N for groups Ti, Al, and Zr, respectively. Significant differences were found for the fracture resistance comparisons of group Ti with groups Al and Zr (Kruskal-Wallis test, P < .001). The test results for the comparison of groups Al and Zr were not significant.

CONCLUSION

All 3 implant-supported restorations have the potential to withstand physiologic occlusal forces applied in the anterior region.

Bond strength of resin cements to H2O2-treated titanium plates

OBJECTIVE

This study investigated the effects of H(2)O(2)-treatment of titanium surfaces on cement shear bond strengths, and characterized H(2)O(2)-treated titanium surfaces.

METHODS

Using 34.5% hydrogen peroxide solution, cp Ti plates (10 mm x 10 mm x 1 mm) were treated by (1) an immersion method, and (2) halogen irradiation while immersed in H(2)O(2) for varying times. A cylindrical block (6 mm diameter, 4 mm height) of four different cements was bonded onto H(2)O(2)-treated surfaces. The cement bond strengths were evaluated under shear mode. Treated surfaces were also characterized for color change, wettability, AC impedance, and transmission electron diffraction of stripped oxide film.

RESULTS

The cement shear bond strength of cp Ti treated with H(2)O(2) and halogen for 160 s was the highest and was approximately 14 times higher than the un-treated control cp Ti plates. Bond strengths are correlated linearly to wettability. The more surface wetted with the cement material, the higher the resultant shear bond strength value.

SIGNIFICANCE

These results suggest that a combined treatment of hydrogen peroxide and halogen light irradiation provides an effective surface condition with appropriate oxide film thickness to enhance the cement bond strength.

Indications for Splinting Implant Restorations

PURPOSE

The purpose of this article was to review the literature concerning the need to splint implants together when restoring them with a provisional restoration immediately after implant placement.

METHODS

The literature is reviewed concerning the rationale for splinting teeth and reports concerning the efficacy of splinting implants together. Based on this team's experience with a prospective series of consecutive 2 to 5 unit provisionalization cases, guidelines are included with case examples for understanding the technique.

CONCLUSION

As long as canine guidance is present, and occlusion is stable, multiunit single quadrant restorations do not need to be splinted when provisionalized.

Treatment planning for multiunit restorations--the use of diagnostic planning to predict implant and esthetic results in patients with congenitally missing teeth

Patients afflicted with congenitally missing teeth are a unique patient population for consideration of treatment with osseointegrated implants. Frequently, these patients have limited development of the alveolar process and differences in spatial position relative to the opposing arch, which places emphasis on ancillary treatment with orthodontics and oral surgery. A thorough diagnostic workup should include an interdisciplinary approach to ensure optimal treatment and timing of treatment in those who are developing. This article outlines considerations for treating these types of patients and scenarios of treatment paths frequently taken to restore the partially dentate and edentulous to esthetics and function.

Oral implant restoration for enhanced oral function

1. The present paper reviews the clinical applications of implant-anchored restorations replacing teeth and defects of the craniofacial skeleton resultant from congenital, traumatic and surgical tissue loss. 2. Different categories of tooth and tissue loss were treated in controlled multicentre prospective clinical trials. More recent developments have been the subject of limited pilot studies. 3. Long-term results and meta-analysis reviews have shown that osseointegrated implant-supported restorations were at least equal to, and in some applications superior to, traditional treatment methods. 4. Based on the outcome of a 30 year research and development programme and validation in numerous clinical trials, osseointegrated implant dental rehabilitation has become a viable treatment alternative for missing teeth and, for some applications, is considered to be a standard of care.

A systematic review of the survival and complication rates of fixed partial dentures (FPDs) after an observation period of at least 5 years. II. Combined tooth-implant-supported FPDs

OBJECTIVES

The objective of this systematic review was to assess the 5- and 10-year survival of combined tooth-implant-supported fixed partial dentures (FPDs) and the incidence of biological and technical complications.

METHODS

An electronic MEDLINE search supplemented by manual searching was conducted to identify prospective and retrospective cohort studies on FPDs with a mean follow-up time of at least 5 years. Patients had to have been examined clinically at the follow-up visit. Assessment of the identified studies and data abstraction was performed independently by two reviewers. Failure and complication rates were analyzed using random-effects Poisson regression models to obtain summary estimates of 5- and 10-year survival proportions.

RESULTS

From a total of 3844 titles and 560 abstracts, 176 articles were selected for full-text analysis, and 13 studies met the inclusion criteria. Meta-analysis of these studies indicated an estimated survival of implants in combined tooth-implant-supported FPDs of 90.1% (95 percent confidence interval (95% CI): 82.4-94.5%) after 5 and 82.1% (95% CI: 55.8-93.6%) after 10 years. The survival rate of FPDs was 94.1% (95% CI: 90.2-96.5%) after 5 and 77.8% (95% CI: 66.4-85.7%) after 10 years of function. There was no significant difference in survival of tooth and implant abutments in combined tooth-implant FPDs. After an observation period of 5 years, 3.2% (95% CI: 1.5-7.2%) of the abutment teeth and 3.4% (95% CI: 2.2-5.3%) of the functionally loaded implants were lost. After 10 years, the corresponding proportions were 10.6% (95% CI: 3.5-23.1%) for the abutment teeth and 15.6% (95% CI: 6.5-29.5%) for the implants. After a 5 year observation period, intrusion was detected in 5.2% (95% CI: 2-13.3%) of the abutment teeth. Intrusion of abutment teeth were almost exclusively detected among non-rigid connections.

CONCLUSION

Survival rates of both implants and reconstructions in combined tooth-implant-supported FPDs were lower than those reported for solely implant-supported FPDs (Pjetursson et al. 2004). Hence, planning of prosthetic rehabilitation may preferentially include solely implant-supported FPDs. However, anatomical aspects, patient centered issues and risk assessments of the residual dentition may still justify combined tooth-implant-supported reconstructions. It was evident from the present search that tooth-implant-supported FPDs have not been studied to any great extent and hence, there is a definitive need for more longitudinal studies examining these reconstructions.

Implant Survival in Periodontally Compromised Patients

BACKGROUND

Relatively little is known on the long-term prognosis of implants inserted in partially edentulous, periodontally compromised patients.

METHODS

A total of 258 conventional implants, 57 two-stage and 201 one-stage implants, which were inserted in 32 and 108 patients, respectively, between June 1988 and June 2002 were followed with respect to their survival, as well as the periodontal parameters bone loss, probing depth, and bleeding on probing. All patients were periodontally compromised who had undergone periodontal surgery and were considered able to maintain a high standard of oral hygiene.

RESULTS

The 5-year survival rates were 97% and 94%, respectively, for the two- and the one-stage implants. The 10-year survival rate remained high at 97% for the two-stage implants, but had dropped to 78% for the one-stage implants. Smoking, short implant length, and insertion during the later period (1995-2002) were found to be associated with an increased failure rate.

CONCLUSIONS

Implants placed in patients with a history of periodontitis have a 5-year survival similar to that observed for implants installed in non-diseased persons. Although the 10-year survival of the one-stage implants was somewhat lower than has been observed for non-diseased patients, implant placement remains a good treatment alternative also for periodontally compromised patients.

Fixed partial denture or single-tooth implant restoration? Statistical considerations for sequencing and treatment

The choice to replace a single missing tooth can be based on the primary decision that the restorability of the tooth is in doubt. Many teeth are decimated by incipient or recurrent caries, trauma, endodontic complications, or periodontal disease which requires extraction. It is our objective to familiarize the participant with literature comparing success rates of fixed partial dentures and single-tooth implant restorations and a repertoire of prosthodontic techniques used in replacement of single missing teeth with osseointegrated dental implants. The fixed partial denture (FPD) has been regarded as the standard of care for some time in replacement of single and multiple missing teeth. Many studies surveying long term survival have been compiled and analyzed to arrive at a generalized outcome. Most of these studies arrive at common conclusions. Studies surveying success of single-tooth implant-supported restorations are not comparably abundant nor survey for comparable time as those for FPDs. Although, many of the outcomes are statistical survival estimates such as Kaplan-Meier survival tables, implant restorations in partially dentate patients are a predictable means of tooth replacement. There are certain factors which make FPD more appropriate and conversely factors which make an implant restoration more appropriate. Indications and contraindications for each treatment scenario will also be reviewed based on the literature and clinical experience. It is hoped that the practitioner will be able to appropriately identify those cases in which either an FPD or an implant restoration is the appropriate treatment option.

Oral rehabilitation with implant-supported fixed partial dentures in periodontitis-susceptible subjects. A 5-year prospective study

BACKGROUND

Comparatively few studies with at least 5 years of follow-up are available that describe the use of implants in prosthetic rehabilitation of partially edentulous patients. Randomized, controlled clinical studies that evaluated the effect of different surface designs of screw-shaped implants on the outcome of treatment are also sparse.

OBJECTIVE

To determine, in a prospective randomized, controlled clinical trial, the outcome of restorative therapy in periodontitis-susceptible patients who, following basic periodontal therapy, had been restored with implants with either a machined- or a rough-surface topography.

MATERIAL AND METHODS

Fifty-one subjects (mean age, 59.5 years), 20 males and 31 females who, following treatment of moderate-to-advanced chronic periodontitis, required implant therapy for prosthetic rehabilitation were recruited. Seventeen of the patients were current smokers. Following the active treatment, all subjects were included in an individually designed maintenance program. A total of 56 fixed partial dentures (FPDs) and a total of 149 screw-shaped, and self-tapping implants (Astra Tech implants) -- 83 in the maxilla and 66 in the mandible -- were installed in a two-stage procedure. Each patient received a minimum of two implants and by randomization every second implant that was installed had been designed with a machined surface and the remaining with a roughened Tioblast surface. Abutment connection was performed 3-6 months after implant installation. Clinical and radiographical examinations were performed following FPD connection and once a year during a 5-year follow-up period. The analysis of peri-implant bone-level alterations was performed on subject, FPD and implant levels.

RESULTS

Four patients and four FPDs were lost to the 5 years of monitoring. One implant (machined surface) did not properly integrate (early failure), and was removed at the time of abutment connection. Three implants were lost during function and a further eight implants could not be accounted for at the 5-year follow-up examination. The overall failure rate at 5 years was 5.9% (subject level), 5.3% (FPD level) and 2.7% (implant level). Radiographic signs of loss of osseointegration were not found at any of the implants during the 5-year observation period. During the first year in function there was on average 0.33 (SD, 0.61) mm loss of peri-implant marginal bone on the subject and FPD levels and 0.31 (0.81) mm on the implant level. During the subsequent 4 years, the peri-implant bone-level alterations were small. The calculated annual change in peri-implant bone level was -0.02 (0.15) on subject and FPD levels and -0.03 (0.20) on the implant level. Thus, the mean total bone-level change over the 5-year interval amounted to 0.41 mm on all three levels of analysis. In the interval between baseline and 5 years, the machined and the Tioblast implants lost on average 0.33 and 0.48 mm, respectively (p>0.05).

CONCLUSION

The present randomized, controlled clinical trial that included partially edentulous periodontitis-susceptible subjects demonstrated that bone loss (i) during the first year of function as well as annually thereafter was small and (ii) did not vary between implants with machined- or rough-surface designs.

Functional behaviour of bone around dental implants

Achieving a long-term stable implant interface is a significant clinical issue when there is insufficient cortical bone stabilisation at implant placement. Clinical outcomes studies suggest that the higher risk implants are those placed in compromised cortical bone (thin, porous, etc.) in anatomical sites with minimal existing trabecular bone (characterised as type IV bone). In establishing and maintaining an implant interface in such an environment, one needs to consider the impact of masticatory forces, the response of bone to these forces and the impact of age on the adaptive capacity of bone. These forces, in turn, have the potential to create localised changes in interfacial stiffness through viscoelastic changes at the interface. Changes in bone as a function of age (e.g. localised hypermineralised osteopetrosis and localised areas of osteopenia) will alter the communication between osteocytes and osteoblasts creating the potential for differences in response of osteoblastic cells in the older population. A key to understanding the biomechanical and functional behaviour of implants in the older population is to control the anticipated modelling and remodelling behaviour through implant design that takes into account how tissues respond to the mechanically active environment.

Functional and Esthetic Considerations for Single-tooth Ankylos Implant-crowns: 8 Years of Clinical Performance

PROBLEM

Following the loss of an anterior natural tooth, the mucogingival complex begins to collapse. The early placement of endosseous dental implants can prevent or reduce the extent of this collapse. If there is a long interval between the loss of the natural tooth and the placement of the implant prosthetic replacement, this collapse tends to increase significantly.

PURPOSE

This paper will report on the clinical success of this implant product in the fabrication of esthetic, functional, and harmonious replacements for missing single, natural teeth for a period of 8 years.

METHOD

A total of 275 single Ankylos implant tooth restorations in the anterior and posterior jaw regions were placed and monitored for 8 years. Of these, 264 implants were restored using the titanium Balance abutments, and only 11 were restored using ceramic abutments. The final restorations were either metal-ceramic or full-ceramic crowns and were cemented with glass ionomer cement.

RESULTS

The survival rate was 98.2%, with only 5 implants being lost during the healing phase. There were no other implant losses in the postloading period that averaged 3.2 years. To date, there have been no mechanical complications associated with the prosthetic components (ie, screw loosening, screw breaking, or crown breaking) for either the titanium or the ceramic abutments.

CONCLUSIONS

Experience with the Ankylos system with single-tooth replacement indications may be considered positive with regard to the esthetic and functional results of the treatment. The lack of mechanical complications and problems with the hard and soft tissue in the loading phase of the implants suggests the functional safety of the tapered connection between implant and abutment.

Long-Term Tooth Survival Following Regenerative Treatment of Intrabony Defects

BACKGROUND

The longevity of the clinical benefits of guided tissue regeneration (GTR) has not been fully explored. The aim of this investigation was to assess the long-term survival of GTR treated sites in terms of clinical attachment level (CAL) stability and tooth loss.

METHODS

A total of 175 patients with one deep intrabony defect were selected for a retrospective investigation of tooth retention and CAL stability. All sites had been treated with GTR more than 2 years previously and had received full periodontal examinations every 2 years for up to 16 years. Definitions of events for survival analyses were tooth loss, loss of > or = 2 mm compared with the CAL observed before GTR treatment, and loss of > or = 2 mm compared with the CAL observed 1 year after completion of GTR.

RESULTS

Teeth were severely compromised by the presence of CAL loss of 10.7 +/- 2.4 mm, probing depths of 8.7 +/- 2.3 mm and deep intrabony defects (average depth 6.6 +/- 2.1 mm). After GTR, CAL gains were 4.6 +/- 2 mm. Average follow up was 8 +/- 3.4 years; 66.9% of subjects strictly complied with a periodontal maintenance program. Tooth survival was greater than 96% more than 10 years after GTR. CAL was equal or coronal with respect to pretreatment in 92% of cases followed for 15 years after treatment, while loss of CAL compared to the 1-year post-GTR result was observed in 37.8% of cases. Cox proportional hazard models indicated that incidence-free survival was negatively affected by smoking and positively affected by full compliance with a periodontal maintenance program in a specialist practice.

CONCLUSIONS

Within the limits of this study, data suggest that tooth retention and clinical improvements following GTR treatment of intrabony defects can be maintained long term in the great majority of cases and thus that regenerative periodontal treatment represents an important alternative for the management of severely compromised teeth.

Effect of implant design on survival and success rates of titanium oral implants: a 10-year prospective cohort study of the ITI Dental Implant System

AIM

The aim of this 10-year study (observation time 8-12 years, mean: 10 years) was to compare the survival rates, success rates and incidences of biological complications using three different implant designs of the ITI Dental Implant System.

MATERIAL AND METHODS

In 89 dental patients treated comprehensively, a total of 112 hollow screw (HS), 49 hollow cylinder (HC) and 18 angulated hollow cylinder (AHC) implants were installed depending on the available bone volume and according to prosthetic needs. One and 10 years after surgical placement, clinical and radiographic parameters were assessed. The incidences of peri-implantitis according to various thresholds were registered over 10 years of maintenance.

RESULTS

Success criteria at 10 years were set at: pocket probing depth (PPD)< or =5 mm, bleeding on probing (BoP)-, bone loss < 0.2 mm annually. The survival rate for HS was 95.4%, for HC 85.7% and for AHC 91.7%. Ninety percent of all the HS, 71% of the HC and 88% of the AHC did not present with an incidence of peri-implantitis over the 10 years, HC having significantly higher incidence of peri-implantitis than HS (P< 0.004). With the success criteria set above, a success rate for HS of 74%, for HC of 63% and for AHC of 61% was identified at 10 years. However, including a definition of PPD< or =6 mm, BoP - and bone loss < 0.2 mm annually for success, the rates for HS were 78%, for HC 65% and for AHC 67%, respectively. Basing success criteria purely on clinical parameters (without radiographic analysis), such as: PPD< or =5 mm and BoP-, the success rates increased to 90%, 76% and 89%, respectively. With PPD< or =6 mm and BoP - as success criteria chosen, the respective rates were 94%, 82% and 94% for HS, HC and AHC implants, respectively.

CONCLUSIONS

A significantly higher survival rate as well as a significantly lower incidence of peri-implantitis was identified for hollow screw design ITI Dental Implants after 10 years of service when compared to hollow cylinder design ITI Dental Implants (95.4% vs. 85.7%; 10% vs. 29%). Depending on the setting of the threshold criteria for success, success rates are highly variable and hence, reporting of success rates with elaboration on the criteria set appears crucial for comparison of different studies.

Survey of systematic reviews in dentistry

BACKGROUND

Although systematic reviews are the backbone of evidence-based dentistry, they have appeared infrequently in the clinical dental literature and their importance may not be recognized by dentists. The authors describe the steps taken in systematic reviews and perform a literature survey to identify published systematic reviews of topics relevant to clinical dentistry.

METHODS

The authors searched MEDLINE and the Cochrane databases of systematic reviews and abstracts of reviews of effectiveness, as well as identified reviews that were known to the authors but not found in the searches. Systematic reviews included in this survey stated the intention to identify all relevant articles within predefined limitations, applied defined exclusion and inclusion criteria, and presented complete raw or synthesized data from included studies.

RESULTS

This literature survey identified 131 systematic reviews, 96 of which had direct clinical relevance. During the past 14 years, clinically relevant systematic reviews have been published with increasing frequency. These reviews vary in the types of studies included and the assessment of those studies. The results of the reviews also varied in their definitiveness, with 17 percent finding the evidence to be insufficient to answer the key question. An additional 50 percent of the 96 reviews hedged in answering the key question, by noting that the supporting evidence was weak in quality or limited in quantity.

CONCLUSION

The number of systematic reviews that address clinical topics in dentistry is small but growing. However, the authors of more than one-half of these reviews believed that the evidence available to answer the key question was not strong.

CLINICAL IMPLICATIONS

As systematic reviews continue to grow, dentistry will become better informed about the adequacy and congruence of the scientific evidence underpinning clinical practice.

Association between periodontal and peri-implant conditions: a 10-year prospective study

OBJECTIVES

The aims of this study were to (1) compare prospectively the clinical and radiographic changes in periodontal and peri-implant conditions, (2) investigate the association of changes in periodontal parameters and peri-implant conditions over a mean observation period of 10 years (8-12 years) after implant installation, and (3) evaluate patient risk factors known to aggravate the periodontal conditions for their potential influence on the peri-implant tissue status.

MATERIALS AND METHODS

Eighty-nine partially edentulous patients with a mean age of 58.9 years (28-88 years) were examined at 1 and 10 years after implant placement. The patients contributed with 179 implants that were placed after comprehensive periodontal treatment and restored with crowns or fixed partial dentures. One hundred and seventy-nine matching control teeth were chosen as controls. Also, the remaining teeth (n=1770) in the dentitions were evaluated. Data on smoking habits and general health aspects were collected at 1 and 10 years as well.

RESULTS

At 10 years, statistically significant differences existed between implants and matching control teeth with regard to most of the clinical and radiographic parameters (P<0.01) with the exception of plaque index (PII) and recession. Multiple regression analyses were performed to associate combinations of periodontal diagnostic parameters to the peri-implant conditions: probing attachment level (PAL) at implants at 10 years was associated with implant location, full-mouth probing pocket depth (PPD) and full-mouth PAL (P=0.0001, r2=0.36). PPD at implants at 10 years correlated to implant location, full-mouth PPD and full-mouth PAL (P<0.001, r2=0.47). Marginal bone level at implants at 10 years was significantly associated to smoking, general health condition, implant location, full-mouth PAL and change over time in full-mouth PPD (P<0.001, r2=0.39).

CONCLUSIONS

These results present evidence for the association between periodontal and peri-implant conditions and the changes in these tissues over 10 years in partially edentulous patients.

Representative marketing-oriented study on implants in the Austrian population. I. Level of information, sources of information and need for patient information

The number of dental implants inserted annually worldwide has been estimated to come close to a million. But the level of information available to patients about realistic, evidence-based treatment options by implants is often enough more than fragmentary, and what is disseminated by the media and the industry does not always reflect evidence-based empirical data. This survey of 1000 adults presented with 18 questions was designed to shed light on several points. These were (1). level of subjective patient information, (2). sources of information and prejudices, (3). future demand for implant treatment and target groups for patient information campaigns, and (4). potential misinformation, information deficits, discrepancies of information and how these come about. Of those questioned, 20% said unprompted that implants were a possibility to replace missing teeth. When prompted, 72% said that they knew about dental implants. Most of those questioned felt poorly informed about the options for replacing missing teeth and many knew less about implants than about other alternatives. The dentist was said to be the desired source of information, but 77% of those questioned reported that their dentists did not practice implant dentistry. More than 79% of those questioned did not know whether their dentist worked with implants. Forty-four percent thought that implants should only be placed by specially trained doctors. Sixty-one percent were of the opinion that dentists who provide implant dentistry were better qualified than their nonimplanting colleagues. Half of those questioned attributed implant failures to allergies and incompatibilities, the other half to poor medical care. Only 29% incriminated poor oral hygiene as a cause of implant failure. Future strategies should be geared to more professional public relations and patient information. Internationally operating qualified implant institutions could contribute much to balance discrepant information.

The assessment of systematic reviews in dentistry

The aim of this study was to assess the quality of systematic reviews of effectiveness of interventions in dentistry. The Database of Abstracts of Reviews of Effectiveness and the Cochrane Database of Systematic Reviews were searched to identify systematic reviews examining the effectiveness of interventions for oral, dental and craniofacial disorders and diseases. Sixty-five reviews were identified and assessed independently by two reviewers. The area most frequently evaluated within the reviews was pain relief/prevention (20/65, 31%) followed by caries and oral medicine. The quality assessment of the identified systematic reviews highlighted key areas where improvements could be made. One major weakness of the reviews was that the search strategies employed were not always adequate. Only 12 reviews (19%) demonstrated an attempt to identify all relevant studies. Other areas of weakness include the screening and quality assessment of primary studies, the pooling of data and examination of heterogeneity, and the interpretation of findings. This investigation shows that the quality of systematic reviews in dentistry could be improved. If future clinical decisions are to be based upon systematic reviews, it is imperative that the reviews address clinically relevant, focused questions and follow a 'transparent', well-designed protocol.

Nonsubmerged and submerged implants in the treatment of the partially edentulous maxilla

BACKGROUND

Dental implants vary in design and surfaces. In addition, different surgical techniques have been used for implant insertion. The ITI Dental Implant System (Straumann AG, Waldenburg, Switzerland) has always required a one-stage technique, whereas the Brånemark System (Nobel Biocare AB, Gothenburg, Sweden) requires a two-stage technique.

PURPOSE

The aim of this study is to compare the outcome of fixed partial bridges in the maxilla supported by both ITI and Brånemark implants in a split-mouth design.

MATERIALS AND METHODS

Twenty-eight patients with a residual anterior dentition in the maxilla were included in this split-mouth study. The Brånemark implants were used on one side and the ITI implants on the other side of the residual dentition according to a randomization procedure. A blocking size of four was used, giving equal probability of placing ITI or Brånemark implants in the right or left side of the jaw. The surgical and prosthetic procedures followed the guidelines given by the manufacturers. The prosthetic treatment with the two-implant systems was performed at the same time, and for that reason the healing period was 6 months for both systems. The observation period for all patients was 1 year after loading.

RESULTS

Two Brånemark implants (in one patient) were lost before loading, and one ITI implant was lost 1 year after loading. There was no significant difference in survival rate. Radiographic examination of the bone level was performed at the time of delivery of the bridge and after 1 year. The mean marginal bone level at baseline was situated 1.9 mm from the reference point for the Brånemark implants and 1.5 mm for the ITI implants. With regard to the insertion depth used, these bone levels indicate that bone loss had taken place before baseline. However, between baseline and the 1-year examination, there was no significant change of the marginal bone (0.2 +/- 0.08 mm at the Brånemark implants and 0.1 +/- 0.11 mm at the ITI implants). The difference between results with the two implants was not statistically significant. Crater-form bone destructions were seen at some ITI implants, indicating periimplantitis. However, at only two implants were there clinical signs of periimplantitis.

CONCLUSIONS

No significant difference in survival rate or in marginal bone change could be demonstrated between the two systems. At some ITI implants (18%), crater-form bone loss was observed.

Outcome of implant therapy in relation to experienced loss of periodontal bone support: a retrospective 5- year study

PURPOSE

The aim of this retrospective study was to analyse bone level alterations over a 5-year period at implants in the maxillary posterior segments in patients with varying experience of periodontal bone loss in the natural dentition before implant placement.

MATERIALS AND METHODS

97 partially dentate patients with a total of 346 Brånemark oral implants in the maxillary posterior segments were included. By assessing the degree of radiographic marginal bone loss in the remaining natural dentition at time of the implant therapy, an age-related bone loss score (ArB-score) was calculated for description of the patient's experience of periodontal destruction. The two end quartiles of the distribution of the subjects with regard to the ArB-score were defined as Non-Perio subjects and Perio subjects, respectively. The primary outcome variables were implant losses (implant failures) and radiographic peri-implant bone loss over the 5-year observation period.

RESULTS

A total of 18 implants were lost during the 5 years, resulting in an overall failure rate of 5.2%. The corresponding failure rate was 3.3% for the Non-Perio and 8.0% for the Perio patients. The peri-implant bone loss from the time of abutment connection to 5 years averaged 1.8 mm (SD 0.7). Of the patients, 34% showed a mean bone loss of > 2 mm and 39% of all implants had experienced a bone loss of 2 mm at the 5-year examination. The Non-Perio and Perio patients showed a mean bone loss of 1.7 mm (0.8) and 2.2 mm (0.8), respectively. Multiple regression analysis revealed a statistically significant relationship between the ArB-score and the peri-implant bone level change from abutment connection to 5 years (P < 0.05). In all, 64% of Perio patients had a mean peri-implant bone loss of > 2 mm from the time of abutment connection, compared to 24% for the Non-Perio patients (P < 0.01). The percentage of implants showing 2 mm of bone loss between abutment connection and 5 years was 62% and 44% in the Perio and Non-Perio groups, respectively (P = 0.055).

CONCLUSION

The results indicate that longitudinal bone loss around implants is correlated to previous experience of loss of periodontal bone support and that periodontitis susceptible subjects may show an increased implant failure rate.

Biologic outcome of implant-supported restorations in the treatment of partial edentulism. part I: a longitudinal clinical evaluation

The purpose of this study was to predict the outcome of implant restorations in the treatment of partial edentulism, taking into account implant interdependency and the effect of several confounding variables. Between December 1982 and June 1998, 1956 Brånemark system implants (1212 and 744 in the maxilla and mandible, respectively, 846 distal to first premolars) were installed in 660 patients (248 males) at the Department of Periodontology of the University Hospitals of the Catholic University of Leuven. Of the 810 restorations installed at the Department of Prosthetic Dentistry of the same hospital, 235 were single crowns, 166 were supported by implants and teeth and 409 were free-standing fixed partial prostheses. An additional 87 restorations was placed in private dental offices and were not included. The patients were followed from implant installation until June 1999. The estimated cumulative survival rates were 91.4% for all implants and 95.8% for all restorations over a period of 16 years. Estimated cumulative survival rates from loading for implant-tooth connected and free-standing implants were, respectively, 93.6% and 97.2%. Neither jaw site nor implant position (anterior-posterior) had any significant effect on the outcome. Short implant length, high number of implants per patient, low number of implants per prosthesis, implants loaded by acrylic-veneered restorations and implants combined with bone grafting present a higher risk hazard for implant failure. The idea of not splinting the implants in a fixed partial prosthesis is promising but needs replication before accepting it.

The single-tooth implant: a viable alternative for single-tooth replacement

BACKGROUND

The use of dental implants for single-tooth replacement cases introduces a challenge to the performance of these restorations. Clinical data suggest that single-tooth implant restorations do not benefit from lateral support from the surrounding dentition as do bridged implants, and that these restorations are subjected to greater masticatory forces. Therefore, single-tooth implants are exposed to an increased risk of failure. This prospective clinical trial was designed to evaluate the cumulative success rate of dual acid-etched single-tooth replacement implants in two clinical centers.

METHODS

The study protocol included 59 patients between 19 and 73 years. Implants were evaluated for mobility, infection, and crestal bone loss from 30.9 to 60 months.

RESULTS

Seventy-one (71) implants were placed in 59 patients, 20 male and 39 female. Forty-seven (47) were placed in the maxilla and 24 in the mandible. The percentages of anterior and posterior implants were 45.1% and 54.9%, respectively. A total of 13 (18.4%) implants were placed in soft, poor quality (Type IV) bone. Beginning 1 month post-implant placement, cases were followed for 30.9 to 60 months with a mean follow-up of 45.9 months. One implant failed (peri-implant infection) yielding an overall success rate of 98.6%.

CONCLUSIONS

This success rate for single-tooth replacement dual acid-etched implants compares favorably with bridged implants and with success rates of other single-tooth implant studies. Dual acid-etched implants performed well even under conditions of poor quality bone, where concomitant bone augmentation was performed, and when used for immediate replacement of extracted teeth.

Long-term clinical effectiveness of oral implants in the treatment of partial edentulism. Seven-year life table analysis of a prospective study with ITI dental implants system used for single-tooth restorations

One hundred and eight-seven ITI implants were prospectively followed from November 1992 to July 2000, in order to evaluate the clinical efficiency and the long-term prognosis in 109 partially edentulous patients (69 women and 40 men; average age 41.3 years). Of these 187 implants, 69.5% were placed in the mandible and 30.5% in the maxilla. After a healing period that ranged from three to six months, the osseointegrated implants (n = 184) were restored with single crowns. Three implants were extracted prior to loading the fixture and were considered early failures. Each implant was reassessed on a yearly basis, both clinically and radiographically. The results of the investigation, which were evaluated according to predefined success criteria, were reviewed in accordance with a life table method. During the follow-up, six cases were deemed to be late failures. In each of these cases, a suppurative infection of the peri-implant tissue was diagnosed: in one implant, the infection could not be eradicated and the implant was removed. When 11 drop-outs were included in the analysis, the cumulative survival and success rates for the whole sample group were 96.77% and 93.6%, respectively. When only prosthetically loaded implants were considered, the results increased to 99.35% for the cumulative survival rate and 96.18% for the cumulative success rate. The analysis on disaggregated data showed better results for maxillary restorations (survival rate 100%) in comparison to mandible restorations (survival rate 95.11%). It was concluded that, under standard anatomic conditions (bone site height > 8 mm, thickness > 6 mm), prosthetic restoration of partially edentulous patients with the ITI system can be described as a reliable and efficient therapy in the long term.

Implant versus tooth-implant supported prostheses in the posterior maxilla: a 2-year report

When implants are used for restoration of a jaw with a residual dentition, the possibility of combining implants with natural abutments may be considered. In a longitudinal comparative study, 26 patients (15 women & 11 men, age 49-84 years) with residual anterior dentitions were treated with two different designs of fixed partial dentures bilaterally in the posterior maxilla. On one side the reconstruction was supported by implants only, while on the contralateral side an implant and a tooth in combination were used. The patients were followed at intervals of 3, 6, 12 and 24 months after loading of the implants. 95 implants were placed, of which 11 non-loaded. A total of 10 implants failed, 7 prior to loading and three within the first three months of service (88.0+/-SE 6.7% cumulative survival for tested implants after two years' follow-up). There was no difference in failure rate for the implants in the two different prosthesis designs. The total mean loss of marginal bone height close to the implants was within acceptable standards, but was more pronounced at the implants not combined with teeth. The results indicate a correlation between the prosthesis design and the loss of marginal bone.

Tilted implants as an alternative to maxillary sinus grafting: a clinical, radiologic, and periotest study

BACKGROUND

Owing to mechanical and anatomic difficulties, implant treatment in the atrophic maxilla represents a challenge. The maxillary sinus floor augmentation procedure is still not universally accepted because of its complexity and its unpredictability.

PURPOSE

In this study, a combination of tilted and axial implants was used in patients with severely resorbed posterior maxillae as an alternative to sinus grafting.

MATERIALS AND METHODS

Twenty-five patients were rehabilitated with 29 fixed partial prostheses supported by 101 Brånemark System implants. Fifty-nine implants were installed in an axial and 42 in a tilted direction. The average follow-up period was 37 months (range: 21-87 mo post loading).

RESULTS

After 5 years, the implant cumulative success rate was 95.2% (survival: rate 100%) for the tilted implants and 91.3% (survival rate: 96.5%) for the axial implants, and the prosthesis survival rate was 100%. At the fifth year, the average marginal bone loss was 1.21 mm for the tilted implants and 0.92 mm for the axial ones. The mean Periotest values (PTV) at loading time were -2.62 and -3.57, and after 5 years the PTVs were -4.73 and -5.00 for the tilted and the axial implants, respectively. During the follow-up, all prostheses but two were mechanically stable, retightening of 18 abutment screws and of 5 gold screws in 14 prostheses was done, and fracture of two abutment screws and two occlusal surfaces was experienced.

CONCLUSIONS

Results indicate that the use of tilted implants is an effective and safe alternative to maxillary sinus floor augmentation procedures.

Clinical evaluation and prosthetic complications of single tooth replacements by non-submerged implants

The aim of the present study was to evaluate single tooth replacements by non-submerged implants. In the time period from 1990 to 1998, 72 patients were consecutively admitted for treatment with a total of 109 solid screw ITI-implants supporting single crowns. All crowns were ceramic to metal fused with a ceramic occlusal surface and mounted to the octa-abutment. The mean observation time was 4.3 years, ranging from >1 to 9 years. The implants were monitored regularly by periimplant parameters. Periapical radiographs using the parallel technique were taken after the healing period and in 1999 for comparative measurements. No implant was lost during the healing phase, while 3 failures occurred after a loaded period of 2.5 and >5 years, respectively. The 5-year cumulative survival rate was 99.1%. In the course of the study, only 2 implants exhibited marginal inflammation that required treatment. The radiographically measured distance (DIB) from the implant shoulder to the first implant-bone contact was significantly increased in 1999 and different between the two readings. However, this difference in DIB was not significant between implants with a short (1 year) and long (>5 years) observation period. It was concluded that changes in the crestal bone level occur mostly in the first postsurgical year. Prosthetic complications were rare, mostly encountered in the first year after loading and often limited to re-tightening of the occlusal screw.

Biological and technical complications and failures with fixed partial dentures (FPD) on implants and teeth after four to five years of function

The aim of this study was to compare the frequency of biological and technical complications with fixed partial dentures (FPDs) on implants, teeth and as mixed tooth-implant supported FPDs over 4 to 5 years of function. All implants belonged to the ITI Dental Implant System. Group I-I (implant FPD) included 33 patients with 40 FPDs, group T-T (tooth FPDs) 40 patients with 58 FPDs, group I-T (mixed tooth-implant FPDs) 15 with 18 FPD. Of the bridge abutments 144 were teeth and 105 were implants. The median number of units replaced by the FPDs was 3 (range 2-14). The mean age of the patients was 55.7 years (range 23-83). Complete failures resulted in the loss of one FPD in each group. Two implants were lost due to fracture secondarily to development of a bone defect. One tooth had a vertical fracture and 1 tooth was lost due to periodontitis. Biological complications (peri-implantitis, PPD > or = 5 mm and BOP+) occurred at 9.6% (10) of the implants. This number was, however, reduced to 5% if the threshold for definition of peri-implantitis was set at PPD > or = 6 mm and BOP+. Biological complications occurred in 11.8% (17) of the abutment teeth (NS compared to implants); 2.8% (4) had secondary caries, 4.9% (7) endodontic problems and 4.1% (6) had periodontitis (PPD > or = 5 mm, BOP+). Ten out of 32 patients with a general health problem indicated a biological complication, whereas 9 out of 53 patients with no general health problem had a biological complication (chi 2: NS). Statistically significantly more technical complications were found in FPDs on implants (chi 2, P < or = 0.05). The technical complications were associated with bruxism. Out of 10 bruxers 6 had a technical complication whereas 13 out of 75 non-bruxers had such a complication (chi 2 < or = 0.01). Extensions were associated with more technical complications (13 out of 35 with extensions versus 9 out of 81 without). In conclusion, favourable clinical conditions were found at tooth and implant abutments after 4-5 years of function. Loss of FPD over 4-5 years occurred at a similar rate with mixed, implant or tooth supported reconstructions. Significantly more porcelain fractures were found in FPDs on implants. Impaired general health status was not significantly associated with more biological failures but bruxism as well as extensions were associated with more technical failures.

The provision of dental implants in the National Health Service Hospital dental services--a national questionnaire

OBJECTIVE

To assess the activity of consultants in restorative dentistry in the United Kingdom in the provision of osseointegrated dental implants within the National Health Service Hospital service and to evaluate their attitudes concerning the relevant medical and oral factors considered in patient selection for implant treatment.

DESIGN/SETTING

Anonymous postal questionnaire in the United Kingdom.

SUBJECTS

Consultants in restorative dentistry.

RESULTS

Out of the sample of 145, 109 consultants (75%) completed the questionnaire in 1999. 54 of the 109 consultants (49.5%) are involved in the provision of osseointegrated implant treatment, treating an average of 29 cases/year (range 2-150). However, over one third of the respondents treated 10 or less cases/year. 89% worked with oral surgeons as an implant team. 68% used Branemark (Nobel Biocare) implants as their main system. The majority of consultants felt that smoking, psychoses and previous irradiation were the most important medical factors that contra-indicated implant retained restorations whilst untreated periodontitis, poor oral hygiene and uncontrolled caries were the most important oral contra-indications. Many centres were experiencing significant problems with the funding of implant treatment with one centre receiving no funding. The implications for patient care and specialist training are discussed.

CONCLUSIONS

There is a marked variation in the number of patients treated with endosseous dental implants within the United Kingdom National Health Service hospitals. Many consultants treat 10 or fewer patients each year. In the main, there is agreement about the factors that contra-indicate implant treatment; these are in line with national guidelines.

Survival of various implant-supported prosthesis designs following 36 months of clinical function

BACKGROUND

The use of endosseous dental implants to replace natural teeth lost to trauma, dental caries, or periodontal disease has become a predictable form of prosthetic treatment since gaining popularity in the early 1980s. While numerous clinical studies have focused on the survival of implants, few address the survival of different prosthesis designs.

METHODS

Beginning in 1991, 882 prostheses supported by more than 2,900 implants (687 patients) were placed by the Department of Veterans Affairs Dental Implant Clinical Research Group (DICRG). These prostheses were divided into five research strata based on arch location. The recommended design for each stratum was: bar-supported overdenture (maxillary completely edentulous); screw-retained hybrid denture (mandibular completely edentulous); screw-retained fixed partial denture (mandibular and maxillary posterior partially edentulous); and cemented single crown (maxillary anterior single tooth). Alternative overdenture designs were utilized in the edentulous arches when the recommended prosthesis could not be fabricated. Prosthesis success rates for the research strata were calculated for an observation time of up to 36 months following prosthesis placement.

RESULTS

Success rates for the maxillary edentulous stratum ranged from 94.6% for the bar-retained overdenture supported by five to six fixtures to 81.8% for the cap-retained overdenture. The mandibular edentulous strata produced success rates of 98.1% for the fixed hybrid prosthesis to 91.7% for the cap-retained prosthesis. Success rates for maxillary and mandibular posterior fixed partial dentures were 94.3% and 92.6%, respectively, while the maxillary anterior single-tooth prosthesis yielded a success rate of 98.1% for the 36-month observation period.

CONCLUSIONS

The recommended prosthesis designs investigated in this study proved to be reliable, with encouraging success rates for an observation period of 36 months following placement.

Biologie Outcome of Single-Implant Restorations as Tooth Replacements: A Long-term Follow-up Study

BACKGROUND

The replacement of a single tooth or several teeth by means of single-implant restorations is an increasingly used method that needs long-term validation.

PURPOSE

The goal of this study was to evaluate the outcome of single-implant restorations by means of fixed restorations and to define the prognosis through marginal bone level estimations.

MATERIALS AND METHODS

From November 1986 to June 1998, 270 Brånemark implants (215 in the upper jaw) were installed in 219 patients (106 males). Both anterior and posterior sites were involved. Of the 263 single restorations, 28 were placed in private dental offices. The patients were followed until June 1999.

RESULTS

Twelve implants failed before or at abutment connection or within 6 months afterward. Only four implants failed later. The cumulative success rates were 93% for the implants and 96.5% for the restorations over a period of 11 years. The marginal bone loss during the first 6 months after abutment connection reached 0.71 mm and then dropped to 0.036 mm annually over a period of 10 years.

CONCLUSIONS

Single-implant restorations (Brånemark System) are a reliable treatment with a good long-term prognosis. Failures were concentrated during the healing period and early loading phase.

Tooth loss and implant replacement

Osseointegrated dental implants are increasingly used to replace missing teeth in a variety of situations ranging from the missing single tooth to complete edentulism. The implant possibility must be carefully considered because treatment involves extended time frames, considerable expense and is not without risk. Accordingly, treatment-planning decisions should have an evidence-based strategy with appropriate risk assessment. Implant systems need to be adequately tested before they are released for general use and success rates should be assessed from peer review scientific publication data and not commercial promotional literature. It is the responsibility of the dentist to ensure the patient is educated so an informed decision can be made on difficult treatment alternatives. The clinical decision making process must respect the issues to assure quality of care and reduction of liability for negligent care. Today, the three-unit fixed bridge can no longer be considered as the standard of care for restoration of a single missing tooth. The evidence has accumulated that the single tooth implant supported replacement is more conservative, more cost-effective and more predictable with respect to long-term outcome in uncomplicated cases.

Influence of Prosthesis Material on the Loading of Implants That Support a Fixed Partial Prosthesis: In Vivo Study

BACKGROUND

Since loading is increasingly believed to be a determining factor in the treatment outcome with oral implants, there is a need to expand the knowledge related to the biomechanics of oral implants and its influencing factors.

PURPOSE

The aim of this study was to investigate the influence of prosthesis material on the distribution and magnitude of load on oral implants carrying a fixed partial prosthesis by in vivo quantification and qualification of this load.

METHODS

Eight patients with in total nine three-unit fixed partial prostheses on three implants and three patients with in total four two-unit fixed partial prostheses on two implants were selected. Both metal and acrylic resin prostheses were made. Strain gauged abutments were used to measure the load on the supporting implants during controlled load application of 50 N on several positions along the occlusal surface of the prostheses and during maximal biting in maximal occlusion. Additional tests were conducted when the three-unit prostheses were supported only by two implants, thereby creating an extension pontic.

RESULTS

A significantly better distribution of bending moments with the metal prostheses in comparison to the acrylic resin prostheses was observed in the case of the three-unit prostheses on two implants. No other difference in load or load distribution with the different prosthesis materials was noted.

CONCLUSION

The clinical significance of the study reveals an increased risk for bending overload of the implants that are closest to the point of load application only in the case of acrylic resin long span prostheses or acrylic resin prostheses with extensions.