Showing papers in "Clinical Oral Implants Research in 2012"

Systematic review of the survival rate and the incidence of biological, technical, and aesthetic complications of single crowns on implants reported in longitudinal studies with a mean follow-up of 5 years

Abstract: Objective To assess the 5-year survival of implant-supported single crowns (SCs) and to describe the incidence of biological, technical, and aesthetic complications. The focused question was: What is the survival rate of implants supporting single crowns and implant-supported crowns with a mean follow-up of 5 years and to which extent do biological, technical, and aesthetic complications occur? Methods A Medline search (2006–2011) was performed for clinical studies focusing on implant-supported SCs with a mean follow-up of at least 5 years. The search was complemented by an additional hand search and the inclusion of 24 studies from a previous systematic review (Jung et al. 2008a). Survival and complication rates were analyzed using random-effects Poisson's regression models to obtain summary estimates of 5- and 10-year proportions. Results Forty-six studies derived from an initial search count of 1083 titles and the complementary publications from the previous systematic review (Jung et al. 2008a) were selected and the data were extracted. Based on the meta-analysis, survival of implants supporting SCs at 5 years amounted to 97.2% (95% CI: 96.3–97.9%), and at 10 years amounted to 95.2% (95% CI: 91.8–97.2%). The survival of implant-supported SCs was 96.3% (95% CI: 94.2–97.6%) after 5 years and 89.4% (95% CI: 82.8–93.6%) after 10 years. For biological complications, a 5-year cumulative soft tissue complication rate of 7.1% (95% CI: 4.4–11.3%) and a cumulative complication rate for implants with bone loss >2 mm of 5.2% (95% CI: 3.1–8.6%) were calculated. Technical complications reached a cumulative incidence of 8.8% (95% CI: 5.1–15.0%) for screw-loosening, 4.1% (95% CI: 2.2–7.5%) for loss of retention, and 3.5% (95% CI: 2.4–5.2%) for fracture of the veneering material after 5 years. The cumulative 5-year aesthetic complication rate amounted to 7.1% (95% CI: 3.6–13.6%). Conclusions The outcomes of the meta-analysis demonstrated high implant survival rates for both the single tooth implants and the respective single crowns after 5 and 10 years. However, technical, biological, and aesthetic complications were frequent.

A systematic review of the survival and complication rates of implant-supported fixed dental prostheses (FDPs) after a mean observation period of at least 5 years.

Abstract: Objectives The objective of this systematic review was to assess the 5- and 10-year survival of implant-supported fixed dental prostheses (FDPs) and to describe the incidence of biological and technical complications. Methods An electronic Medline search complemented by manual searching was conducted to identify prospective and retrospective cohort studies and case series on FDPs with a mean follow-up time of at least 5 years. Patients had to have been examined clinically at the follow-up visit. Failure and complication rates were analyzed using standard and random-effects Poisson regression models to obtain summary estimates of 5-year and 10-year survival and complication rates. Results The updated search provided 979 titles and 257 abstracts. Full-text analysis was performed for 90 articles resulting in a total 32 studies that met the inclusion criteria. Meta-analysis of these studies indicated an estimated survival of implants supporting FDPs of 95.6% after 5 years and 93.1% after 10 years. When machined surface implants were excluded from the analysis and only rough surface implants included, the survival rate increased to 97.2% after 5 years. The survival rate of implant-supported FDPs was 95.4% after 5 years and 80.1% after 10 years of function. When the analysis was done exclusively for metal–ceramic FDPs, hence the old gold–acrylic FDPs were excluded, the survival rate increased significantly. The survival rate of metal–ceramic implant-supported FDPs was 96.4% after 5 years and 93.9% after 10 years. Only 66.4% of the patients were free of any complications after 5 years. The most frequent complications over the 5-year observation period were fractures of the veneering material (13.5%), peri-implantitis and soft tissue complications (8.5%), loss of access hole restoration (5.4%), abutment or screw loosening (5.3%), and loss of retention of cemented FDPs (4.7%). Conclusion It may be concluded that implant-supported fixed dental prostheses (FDPs) are a safe and predictable treatment method with high survival rates. However, biological and technical complications were frequent (33.6%). To minimize the incidence of complications, dental professionals should make great effort in choosing reliable components and materials for implant-supported FDPs and the patients should be placed in well-structured maintenance system after treatment.

A systematic review of post-extractional alveolar hard and soft tissue dimensional changes in humans.

Abstract: Background Removal of teeth results in both horizontal and vertical changes of hard and soft tissue dimensions. The magnitude of these changes is important for decision-making and comprehensive treatment planning, with provisions for possible solutions to expected complications during prosthetic rehabilitation. Objectives To review all English dental literature to assess the magnitude of dimensional changes of both the hard and soft tissues of the alveolar ridge up to 12 months following tooth extraction in humans. Methods An electronic MEDLINE and CENTRAL search complemented by manual searching was conducted to identify randomized controlled clinical trials and prospective cohort studies on hard and soft tissue dimensional changes after tooth extraction. Only studies reporting on undisturbed post-extraction dimensional changes relative to a fixed reference point over a clearly stated time period were included. Assessment of the identified studies and data extraction was performed independently by two reviewers. Data collected were reported by descriptive methods. Weighted means and percentages of the dimensional changes over time were calculated where appropriate. Results The search provided 3954 titles and 238 abstracts. Full text analysis was performed for 104 articles resulting in 20 studies that met the inclusion criteria. In human hard tissue, horizontal dimensional reduction (3.79 ± 0.23 mm) was more than vertical reduction (1.24 ± 0.11 mm on buccal, 0.84 ± 0.62 mm on mesial and 0.80 ± 0.71 mm on distal sites) at 6 months. Percentage vertical dimensional change was 11–22% at 6 months. Percentage horizontal dimensional change was 32% at 3 months, and 29–63% at 6–7 months. Soft tissue changes demonstrated 0.4–0.5 mm gain of thickness at 6 months on the buccal and lingual aspects. Horizontal dimensional changes of hard and soft tissue (loss of 0.1–6.1 mm) was more substantial than vertical change (loss 0.9 mm to gain 0.4 mm) during observation periods of up to 12 months, when study casts were utilized as a means of documenting the changes. Conclusions Human re-entry studies showed horizontal bone loss of 29–63% and vertical bone loss of 11–22% after 6 months following tooth extraction. These studies demonstrated rapid reductions in the first 3–6 months that was followed by gradual reductions in dimensions thereafter.

The epidemiology of peri-implantitis.

Abstract: Aim To review the literature on the prevalence and incidence of peri-implantitis. Methods Out of 322 potentially relevant publications we identified 29 articles concerning 23 studies, with information on the presence of signs of peri-implantitis in populations of at least 20 cases. Results and conclusions All studies provided data from convenience samples, typically from patients who were treated in a clinical center during a certain period, and most data were cross-sectional or collected retrospectively. Based on the reviewed papers one may state that the prevalence of peri-implantitis seems to be in the order of 10% implants and 20% patients during 5-10 years after implant placement but the individual reported figures are rather variable, not easily comparable and not suitable for meta-analysis. Factors that should be considered to affect prevalence figures are the disease definition, the differential diagnosis, the chosen thresholds for probing depths and bone loss, differences in treatment methods and aftercare of patients, and dissimilarities in the composition of study populations. Smoking and a history of periodontitis have been associated with a higher prevalence of peri-implantitis.

Surgical protocols for ridge preservation after tooth extraction. A systematic review.

Abstract: Objective This systematic review aims to evaluate the scientific evidence on the efficacy in the surgical protocols designed for preserving the alveolar ridge after tooth extraction and to evaluate how these techniques affect the placement of dental implants and the final implant supported restoration. Material and methods A thorough search in MEDLINE-PubMed, Embase and the Cochrane Central Register of controlled trials (CENTRAL) was conducted up to February 2011. Randomized clinical trials and prospective cohort studies with a follow-up of at least 3 months reporting changes on both the hard and soft tissues (height and/or width) of the alveolar process (mm or %) after tooth extraction were considered for inclusion. Results The screening of titles and abstracts resulted in 14 publications meeting the eligibility criteria. Data from nine of these 14 studies could be grouped in the meta-analyses. Results from the meta-analyses showed a statistically significant greater ridge reduction in bone height for control groups as compared to test groups (weighted mean differences, WMD = −1.47 mm; 95% CI [−1.982, −0.953]; P < 0.001; heterogeneity: I2 = 13.1%; χ2P-value = 0.314) and a significant greater reduction in bone width for control groups compared to the test groups (WMD = −1.830 mm; 95% CI [−2.947, −0.732]; P = 0.001; heterogeneity: I2 = 0%; χ2P-value = 0.837). Subgroup analysis was based on the surgical protocol used for the socket preservation (flapless/flapped, barrier membrane/no membrane, primary intention healing/no primary healing) and on the measurement method utilized to evaluate morphological changes. Meta-regression analyses demonstrated a statistically significant difference favoring the flapped subgroup in terms of bone width (meta-regression; slope = 2.26; 95% IC [1.01; 3.51]; P = 0.003). Conclusions The potential benefit of socket preservation therapies was demonstrated resulting in significantly less vertical and horizontal contraction of the alveolar bone crest. The scientific evidence does not provide clear guidelines in regards to the type of biomaterial, or surgical procedure, although a significant positive effect of the flapped surgery was observed. There are no data available to draw conclusions on the consequences of such benefits on the long-term outcomes of implant therapy.

Cemented and screw‐retained implant reconstructions: a systematic review of the survival and complication rates

Abstract: OBJECTIVES: To assess the 5-year survival rates and incidences of complications of cemented and screw-retained implant reconstructions. METHODS: An electronic Medline search complemented by manual searching was conducted to identify randomized controlled clinical trials (RCTs), and prospective and retrospective studies giving information on cemented and screw-retained single-unit and multiple-unit implant reconstructions with a mean follow-up time of at least 1 year. Assessment of the identified studies and data abstraction were performed independently by three reviewers. Failure rates were analyzed using Poisson regression models to obtain summary estimates and 95% confidence intervals of failure rates and 5-year survival proportions. RESULTS: Fifty-nine clinical studies were selected from an initial yield of 4511 titles and the data were extracted. For cemented single crowns the estimated 5-year reconstruction survival was 96.5% (95% confidence interval (CI): 94.8-97.7%), for screw-retained single crowns it was 89.3% (95% CI: 64.9-97.1%) (P = 0.091 for difference). The 5-year survival for cemented partial fixed dental prostheses (FDPs) was 96.9% (95% CI: 90.8-99%), similar to the one for screw-retained partial FDPs with 98% (95% CI: 96.2-99%) (P = 0.47). For cemented full-arch FDPs the 5-year survival was 100% (95% CI: 88.9-100%), which was somewhat higher than that for screw-retained FDPs with 95.8% (95% CI: 91.9-97.9%) (P = 0.54). The estimated 5-year cumulative incidence of technical complications at cemented single crowns was 11.9% and 24.4% at screw-retained crowns. At the partial and full-arch FDPs, in contrast, a trend to less complication at the screw-retained was found than at the cemented ones (partial FDPs cemented 24.5%, screw-retained 22.1%; full-arch FDPs cemented 62.9%, screw-retained 54.1%). Biological complications like marginal bone loss >2 mm occurred more frequently at cemented crowns (5-year incidence: 2.8%) than at screw-retained ones (5-year incidence: 0%). CONCLUSION: Both types of reconstructions influenced the clinical outcomes in different ways, none of the fixation methods was clearly advantageous over the other. Cemented reconstructions exhibited more serious biological complications (implant loss, bone loss >2 mm), screw-retained reconstructions exhibited more technical problems. Screw-retained reconstructions are more easily retrievable than cemented reconstructions and, therefore, technical and eventually biological complications can be treated more easily. For this reason and for their apparently higher biological compatibility, these reconstructions seem to be preferable.

A systematic review on survival and success rates of implants placed immediately into fresh extraction sockets after at least 1 year

Abstract: Background Type I immediate implant placement has gained popularity because it may reduce treatment time, number of surgeries and post-extraction bone loss. However, this is potentially challenged by inadequate keratinized mucosa for flap adaptation and difficulties in achieving primary stability. Moreover, it has been proven that post-extraction bone loss is an inevitable biological process, which affects treatment outcomes. Objectives To estimate survival and success rates of implants and the implant-supported prostheses, the prevalence of biological, technical and aesthetic complications, and the magnitude of soft and hard tissue changes following implant placement immediately into fresh extraction sockets. Material and methods An electronic search in MEDLINE (PubMed) and the Cochrane Library from 1991 to July 2010 was performed to include prospective studies on immediate implants with a mean follow-up time of at least 1 year. The survival rates were computed using the STATA statistical software. Weighted means of soft and hard tissue changes were obtained by the inverse variance method. Results A total of 46 prospective studies, with a mean follow-up time of 2.08 years, were included. The annual failure rate of immediate implants was 0.82% (95% CI: 0.48–1.39%), translating into the 2-year survival rate of 98.4% (97.3–99%). Among the five factors analysed (reasons for extraction, antibiotic use, position of implant [anterior vs. posterior, maxilla vs. mandible), type of loading], only the regimen of antibiotic use affected the survival rate significantly. Lower failure rates were found in groups that were provided with a course of post-operative antibiotics. The success of implant therapy was difficult to assess due to scarce reporting on biological, technical and aesthetic complications. Soft tissue changes occurred mostly in the first 3 months after the provision of restoration, and then stabilized towards end of the first year. Marginal bone loss predominantly took place in the first year after implant placement, with a magnitude generally less than 1 mm. Controversy on hard tissue preservation with platform-switching technique remained unsolved. Conclusions Despite the high survival rate observed, more long-term studies are necessary to determine the success of implant treatment provided immediately after tooth extraction. Special attention has to be given to aesthetic outcomes.

Evidence-based knowledge on the biology and treatment of extraction sockets.

Abstract: Objectives The fresh extraction socket in the alveolar ridge represents a special challenge in everyday clinical practice. Maintenance of the hard and soft tissue envelope and a stable ridge volume were considered important aims to allow simplifying subsequent treatments and optimizing their outcomes in particular, when implants are planned to be placed. Material and Methods: Prior to the consensus meeting four comprehensive systematic reviews were written on two topics regarding ridge alteration and ridge preservation following tooth extraction and implant placement following tooth extraction. During the conference these manuscripts were discussed and accepted thereafter. Finally, consensus statements and recommendations were formulated. Results: The systematic reviews demonstrated that the alveolar ridge undergoes a mean horizontal reduction in width of 3.8 mm and a mean vertical reduction in height of 1.24 mm within 6 months after tooth extraction. The techniques aimed at ridge preservation encompassed two different approaches: i) maintaining the ridge profile, ii) enlarging the ridge profile. Regarding timing of implant placement the literature showed that immediate implant placement leads to high implant survival rates. This procedure is primarily recommended in premolar sites with low esthetic importance and favorable anatomy. In the esthetic zone, however, a high risk for mucosal recession was reported. Hence, it should only be used in stringently selected situations with lower risks and only by experienced clinicians. In molar sites a high need for soft and hard tissue augmentation was identified. Conclusions: Future research should clearly identify the clinical and patient benefits resulting from ridge preservation compared with traditional procedures. In addition, future research should also aim at better identifying parameters critical for positive treatment outcomes with immediate implants. The result of this procedure should be compared to early and late implant placement.

Reversibility of experimental peri-implant mucositis compared with experimental gingivitis in humans

Abstract: To monitor clinical, microbiological and host-derived alterations occurring around teeth and titanium implants during the development of experimental gingivitis/mucositis and their respective healing sequence in humans.

E.A.O. guidelines for the use of diagnostic imaging in implant dentistry 2011. A consensus workshop organized by the European Association for Osseointegration at the Medical University of Warsaw.

Abstract: Diagnostics imaging is an essential component of patient selection and treatment planning in oral rehabilitation by means of osseointegrated implants. In 2002, the EAO produced and published guidelines on the use of diagnostic imaging in implant dentistry. Since that time, there have been significant developments in both the application of cone beam computed tomography as well as in the range of surgical and prosthetic applications that can potentially benefit from its use. However, medical exposure to ionizing radiation must always be justified and result in a net benefit to the patient. The as low a dose as is reasonably achievable principle must also be applied taking into account any alternative techniques that might achieve the same objectives. This paper reports on current EAO recommendations arising from a consensus meeting held at the Medical University of Warsaw (2011) to update these guidelines. Radiological considerations are detailed, including justification and optimization, with a special emphasis on the obligations that arise for those who prescribe or undertake such investigations. The paper pays special attention to clinical indications and radiographic diagnostic considerations as well as to future developments and trends.

Does residual cement around implant‐supported restorations cause peri‐implant disease? A retrospective case analysis

Abstract: Objectives The purpose of this study was to determine the relationship between patients with a history of periodontitis and development of cement-related peri-implant disease. Materials and methods Seventy-seven patients with 129 implants for this retrospective analysis were selected from completed implant cases that were scheduled for regular maintenance or had experienced mechanical or biological complications between years 2006 and 2011 in private practice. Implants with extracoronal residual cement and implants without cement remnants were analyzed. The selected cases were further divided into two groups – implants in patients with history of periodontitis (1) and implants in periodontitis-free individuals (2). The selection of these groups was made on the basis of treatment history and orthopantomograph. As a control group, a set of 238 screw-retained implant restorations, delivered to 66 patients during the same period of time was examined. The incidence of peri-implant disease among implants in all groups was calculated. Results Peri-implant disease was evident in 62 of 73 implants with cement remnants (85%). All implants in group 1 developed peri-implantitis – 4 early and 35 delayed disease cases. In the periodontally healthy group, 20 of 31 implants were diagnosed with peri-implant mucositis, 3 implants had early peri-implantitis, and 11 implants with cement remnants did not develop biological complications. In the group of implants without cement remnants, peri-implant disease was diagnosed in 17 of 56 cases (30%). In contrast, only two occurrences of peri-implant disease were registered in the control group of screw-retained restorations (1.08%). Conclusions Implants with cement remnants in patients with history of periodontitis may be more likely to develop peri-implantitis, compared with patients without history of periodontal infection.

Accuracy of computer‐aided implant placement

Abstract: Aim To assess the accuracy of static computer-guided implant placement. Material and methods Electronic and manual literature searches were conducted to collect information on the accuracy of static computer-guided implant placement and meta-regression analyses were performed to summarize and analyse the overall accuracy. The latter included a search for correlations between factors such as: support (teeth/mucosa/bone), number of templates, use of fixation pins, jaw, template production, guiding system, guided implant placement. Results Nineteen accuracy studies met the inclusion criteria. Meta analysis revealed a mean error of 0.99 mm (ranging from 0 to 6.5 mm) at the entry point and of 1.24 mm (ranging from 0 to 6.9 mm) at the apex. The mean angular deviation was 3.81° (ranging from 0 to 24.9°). Significant differences for all deviation parameters was found for implant-guided placement compared to placement without guidance. Number of templates used was significant, influencing the apical and angular deviation in favour for the single template. Study design and jaw location had no significant effect. Less deviation was found when more fixation pins were used (significant for entry). Conclusion Computer-guided implant placement can be accurate, but significant deviations have to be taken into account. Randomized studies are needed to analyse the impact of individual parameters in order to allow optimization of this technique. Moreover, a clear overview on indications and benefits would help the clinicians to find the right candidates.

Osseointegration – communication of cells

Abstract: Background The article provides the scientific documentation for the 3D animated film – “Osseointegration – Communication of cells”. Aim The aim of this article and of the film is to visualise the molecular and cellular events during the healing of an osseous wound after installation of a dental implant with special emphasis on the process of osseointegration. Material and Results In this review article for didactic reasons the concept of the four phases of a healing soft tissue wound was transferred to a bone wound after insertion of a dental implant: haemostasis, inflammatory phase, proliferative phase and remodelling phase. Wound healing throughout these phases is the result of a coordinated action of different cell types which communicate with each other by their interaction using signalling molecules like cytokines, extracellular matrix proteins and small molecules. A regular sequence of cell types controlled by adequate concentrations of signalling molecules results in undisturbed healing. Disturbed healing is associated with a continuation of the early inflammatory phase and the development of a toxic wound environment. The latter is characterized by high counts of polymorphnuclear cells, high concentrations of toxic radicals and proteolytic enzymes and low concentrations of growth factors and extracellular matrix molecules. Clinically the development of a toxic wound environment should be avoided, e.g. by antibacterial measures. Discussion and Conclusion Experiencing implant osseointegration as a biological process may provide the clinician new targets to improve the therapy with dental implants.

Residual periodontal pockets are a risk indicator for peri-implantitis in patients treated for periodontitis.

Abstract: Objectives The aim of this retrospective study was to compare the clinical outcomes of implant treatment in periodontally compromised and periodontally healthy patients (PHP), with a minimum follow-up period of 5 years. Methods Thirty treated periodontally compromised patients (PCP) and 30 PHP, with a total of 117 Straumann implants (PCP = 56, PHP = 61) were matched for age, gender, smoking and implant characteristics. The PCP group was further stratified with patients having at least one periodontal pocket ≥6 mm at follow-up examination allocated to a “residual periodontitis” (RP) group, while the remaining patients were assigned to a “no residual periodontitis” (NRP) group. These groups were compared with respect to probing pocket depth (PPD), bleeding on probing (BOP) and marginal bone loss. Results The mean follow-up period in the PCP and PHP groups was 7.99 years (range 5.04–14.40) and 8.20 years (range 5.00–13.46) respectively. There was no difference in mean PPD between the PCP and PHP groups, but the prevalence of implants with PPD ≥5 mm + BOP was greater in the PCP group than in the PHP group, at both implant- (27% vs. 13%) and patient- (37% vs. 17%) level analyses. Mean implant PPD was significantly greater in the RP group (3.18 mm) than in both the NRP (2.67 mm) and PHP (2.81 mm) groups. Mean bone loss was also significantly greater in the RP group (0.68 mm) than in the NRP (0.23 mm) and PHP groups (0.26 mm). The prevalence of bone loss and PPD ≥5 mm + BOP at the implant level was significantly greater for the RP group compared with both the NRP and PHP groups. Conclusions Implants in PCP with residual pocketing at follow-up had increased PPD and bone loss compared with implants placed in PHP and PCP without residual pocketing. Hence, it is the maintenance of periodontal health rather than a previous history of periodontitis that is the critical determinant of increased risk of peri-implantitis, highlighting the importance of effective periodontal therapy and maintenance in patients with a history of periodontitis.

Internal vs. external connections for abutments/reconstructions: a systematic review

Abstract: The objectives of the review were (1) to evaluate the accuracy of implant-level impressions in cases with internal and external connection abutments/reconstructions, and (2) to evaluate the incidence of technical complications of internal and external connection metal- or zirconia-based abutments and single-implant reconstructions.

Is there a need for keratinized mucosa around implants to maintain health and tissue stability

Abstract: Aim The objective of the present review was to analyze the literature with regard to the need for keratinized mucosa around implants to maintain health and tissue stability. Methods Human and animal studies were identified through electronic and hand searches. Predetermined outcome measures were (i) implant loss, (ii) peri-implant health, (iii) oral hygiene, (iv) soft-tissue recession, (v) change in marginal bone level, and (vi) patient-centered outcomes. With respect to outcome variables, change in “attachment level”, soft-tissue recession and change in peri-implant bone level were only retrieved from longitudinal studies. For remaining parameters, cross-sectional studies were also considered. Results Nineteen relevant publications were identified (17 human and 2 animal studies). Due to marked heterogeneity in study design and reported data, no statistical analysis of retrieved data was feasible. Twelve human studies reported plaque scores for sites with “adequate” (≥2 mm) and “inadequate” (<2 mm) width of keratinized mucosa, and in five studies, an “inadequate” width was associated with a significant higher plaque score. Half of the studies showed significantly higher bleeding scores at implants with < 2 mm of keratinized mucosa, while the majority of publications (8 of 10) found no differences for probing depths. Two of three longitudinal studies reporting on recessions described no long-term differences with regard to the amount of keratinized mucosa. Evidence on the effect of keratinized mucosa on bone-level changes or implant loss was scarce, and no conclusions could be drawn. No article reporting patient-centered outcomes could be identified. Conclusion Collectively, the findings of this review show that evidence in support of the need for keratinized tissues around implants to maintain health and tissue stability is limited.

Peri-implantitis susceptibility as it relates to periodontal therapy and supportive care

Abstract: To assess the long-term survival of implants inserted in periodontally susceptible patients and to investigate the influence of residual pockets on the incidence of peri-implantitis and implant loss.

Clinical advantages of computer-guided implant placement: a systematic review.

Abstract: Objectives To systematically scrutinize the current scientific literature regarding the clinical advantages of computer guidance of implant placement. Materials and methods Four electronic databases were searched using specified indexing terms. The reference lists of publications were also searched manually. For inclusion, publications had to meet pre-established criteria. Results The searches yielded 1028 titles and abstracts. After data extraction and interpretation, 28 publications and 2 systematic reviews remained for inclusion. Fifteen studies were prospective observational and four were retrospective observational. Nine studies included a control group (controlled clinical trials) of which seven were prospective and two retrospective. Only three of the prospective studies were randomized (RCT's). A total of 852 patients were treated with 4032 implants using computer-guided implant surgery. The number of patients included in each study ranged from 6 to 206. The age ranged from 16 to 92 years and the follow-up period varied between 1 and 49 months. Conclusions The limited scientific evidence available suggests that guided placement has at least as good implant survival as conventional protocols. However, several unexpected procedure-linked adverse events during guided implant placement indicate that the clinical demands on the surgeon were no less than those during conventional placement. A clinical advantage with flapless guided surgery is that the technique is likely to decrease pain and discomfort in the immediate postoperative period.

Does bone mineral density influence the primary stability of dental implants? A systematic review

Abstract: Objective: The aim of this systematic review was to investigate the influence of bone mineral density on the primary stability of dental implants. Material and methods: A search of health science databases (Cochrane Library, MEDLINE-PubMed, ISI Web of Knowledge, EMBASE, LILACS) and grey literature was performed, including papers published until January 2011. The main key words used were “bone density” (MeSH/DeCS), “dental implant” (MeSH/DeCS), “implant stability”, “implant stability quotient”, “ISQ”, “resonance frequency analysis”, “RFA”, “Osstell”, “Periotest value”, “PTV”, “Periostest”, “insertion torque”, “placement torque”, “cutting torque”. The inclusion criteria comprised observational clinical studies performed in patients who received dental implants for rehabilitation; studies that evaluated the association between bone mineral density and implant primary stability; bone density assessment performed by measurement of Hounsfield units using cone beam computed tomography; and dental implant primary stability evaluated by ISQ value, PTV value or insertion torque measurement. The articles selected were carefully read and classified as low, moderate and high methodological quality, and data of interest were tabulated. Results: Ten articles met the inclusion criteria, but only seven were included because of overlapping patients. They were classified as low or moderate methodological quality and control of bias, and presented positive association between primary stability and bone density. Conclusions: There is a positive association between implant primary stability and bone mineral density of the receptor site. However, the methodological quality and control of bias of the studies should be improved to produce stronger evidences. To cite this article: Marquezan M, Osorio A, Sant'Anna E, Souza MM, Maia L, Does bone mineral density influence the primary stability of dental implants? A systematic review. Clin. Oral Impl. Res. 23, 2012; 767–774. doi: 10.1111/j.1600-0501.2011.02228.x

Implant survival and complications. The Third EAO consensus conference 2012

Abstract: OBJECTIVES: The task of this working group was to analyze biological, technical and aesthetic complications of single crowns on implants and fixed dental prostheses with or without cantilevers on implants over 5 years or more. In addition, the group analyzed economic aspects on such implant treatment. MATERIALS AND METHODS: A systematic search of the relevant literature was conducted and critically reviewed. Four manuscripts were presented to cover the topics. RESULTS: The consensus statements prepared by the group and later accepted at the plenary session as well as suggestions for future research are presented in this article. The four reviews by Jung et al., Pjetursson et al., Romeo & Storelli and Scheuber et al. are printed separately and present detailed analyses of the research topics.

Peri-implant tissue destruction. The Third EAO Consensus Conference 2012.

Abstract: Objective The task of this working group was to update the existing knowledge base regarding the prevalence of peri-implant tissue destruction, the role of occlusal overload, and the outcome of non-surgical and surgical treatment. Materials and methods The literature was systematically searched and critically reviewed. Four manuscripts were presented in key areas deemed to be essential for the current understanding of the magnitude of the clinical entity peri-implantitis. The role of overload as an etiological component was reviewed. Also available data on the results from non-surgical and surgical interventions for the control of tissue destruction were presented. Results The consensus statements following plenary session approval, clinical implications, and directions for future research based on the group discussions are presented in this article. The results and conclusions of the systematic review process are presented by the respective authors in the subsequent papers.

Clinical and microbiological characteristics of peri-implantitis cases: a retrospective multicentre study.

Abstract: Objectives The aim of this study was to follow patient cases retrospectively in a longitudinal manner from the time of implant placement to the time they were diagnosed with peri-implant disease, and to identify associated clinical and microbiological features of peri-implant disease. Material and methods A total of 281 patient cases were chosen from the archives of the Oral Microbiological Diagnostic Laboratory, Gothenburg, Sweden, based on bacterial samples taken from diseased implants. A form was designed and filled in separately for each case including data on patient, implant and disease profile. Results Most cases were severe peri-implantitis cases (91.4%). In 41.3% of the patients, peri-implantitis was developed early, already after having implants in function less than 4 years. The type of implant surface was significantly associated with the time in years implants were in function, before disease was developed (P < 0.05). The microbiological results by both culture and checkerboard analysis, although failed to fully correspond to the severity of the disease in terms of magnitude, proved to show that peri-implantitis is a polymicrobial anaerobic infection with increased number of AGNB (aerobic Gram-negative bacilli) in 18.6% of the patients. Conclusions Peri-implantitis is a biological complication of implants in function that poses a threat to their long-term survival. It may develop earlier around implants with rough surfaces and it may represent a true infection. Microbiological sampling methods should be improved and uniformed so as to fully unveil the microbiological profile of the disease.

Ten‐year results of a three arms prospective cohort study on implants in periodontally compromised patients. Part 2: clinical results

Abstract: Objectives The aim of this study was to compare long-term outcomes of implants placed both in patients treated for periodontitis and in periodontally healthy patients (PHP). Material and methods One hundred and twelve partially edentulous patients were consecutively enrolled in private specialist practice and divided into three groups according to their initial periodontal condition: PHP, moderately periodontally compromised patients (PCP) and severely PCP. Implants were placed to support fixed prostheses, after successful completion of initial periodontal therapy [full-mouth plaque score (FMPS) <25%, full-mouth bleeding score (FMBS) <25%]. At the end of active periodontal treatment (APT), patients were asked to follow an individualized supportive periodontal therapy (SPT) program. Diagnosis and treatment of peri-implant biological complications was performed according to cumulative interceptive supportive therapy. At 10 years, clinical measures were recorded by two calibrated operators, blinded to the initial patient classification, on 101 patients, as 11 were lost to follow-up. The number of sites treated according to therapy modalities C and D (antibiotics and/or surgery) during the 10 years was registered. Results Eighteen implants were removed for biological complications. Antibiotic and/or surgical therapy was performed in 10.7% of cases in PHP, in 27% of cases in moderate PCP and in 47.2% cases in severe PCP, with a statistically significant differences between PHP and severe PCP (P = 0.002). At the final examination, the percentage of implants, with at least one site which presented a PD ≥6 mm, was respectively 1.7% for PHP, 15.9% for moderate PCP and 27.2% for severe PCP, with a statistically significant difference between PHP and moderate PCP (P = 0.005) and PHP and severe PCP (P = 0.0001). Conclusion Patients with a history of periodontitis presented a statistically significant higher number of sites which required additional treatment. Therefore, patients with a history of periodontitis should be informed that they are more at risk for peri-implant disease. This underlines the value of the SPT in enhancing long-term outcomes of implant therapy, particularly in subjects affected by periodontitis. Therefore, the approach for multiple preventive dental extractions and implant placement, based on the assumption the implants perform better than teeth, should be followed with extreme caution.

Ridge preservation after tooth extraction.

Abstract: Background Following tooth extraction, the alveolar ridge will undergo dimensional changes. This change may complicate the subsequent restorative procedure when oral implants are chosen. “Alveolar ridge preservation” has been assessed in various studies. Aim To evaluate the more recent studies on this topic and to explore new insights under this topic. Material and methods Animal studies and clinical studies have addressed different techniques. Results and conclusions Implants placed into the fresh extraction sockets do not prevent the resorption of the alveolar bone. Simultaneous guided bone regeneration could partially resolve alveolar bone resorption. The use of root-formed implants does not preserve alveolar ridges. Moreover, various bone substitutes have been tested: magnesium-enriched hydroxyapatite, human demineralized bone matrix, and deproteinized bovine bone mineral have been shown to be effective in ridge preservation. Applying the guided bone regeneration principle using bone substitutes together with a collagen membrane has shown clear effects on preserving alveolar ridge height as well as ridge width. Soft tissue grafts or primary closure did not show beneficial effect on preserving the alveolar bone.

Maxillary sinus floor augmentation with Bio-Oss or Bio-Oss mixed with autogenous bone as graft: a systematic review

Abstract: Aims: The objective of the present systematic review was to test the hypothesis of no differences in the implant treatment outcome when Bio-Oss or Bio-Oss mixed with autogenous bone is used as graft for the maxillary sinus floor augmentation (MSFA) applying the lateral window technique. Material and methods: A MEDLINE (PubMed) search in combination with a hand search of relevant journals was conducted by including human studies published in English from January 1, 1990 to June 1, 2010. The search provided 879 titles and 35 studies fulfilled the inclusion criteria. Considerable variation in the included studies prevented meta-analysis from being performed and no long-term study comparing MSFA with the two treatment modalities was identified. Also, the survival of suprastructures after the two augmentation procedures was not compared within the same study. Results: The 1-year implant survival was compared in one study demonstrating no statistically significant difference. The implant survival was 96% with Bio-Oss and 94% with a mixture of 80% Bio-Oss and 20% autogenous mandibular bone. Addition of a limited amount of autogenous bone to Bio-Oss seemed not to increase the amount of new bone formation and bone-to-implant contact compared with Bio-Oss. Conclusions: Therefore, the hypothesis of no differences between the use of Bio-Oss or Bio-Oss mixed with autogenous bone as graft for MSFA could neither be confirmed nor rejected. To cite this article: Jensen T, Schou S, Stavropoulos A, Terheyden H, Holmstrup P. Maxillary sinus floor augmentation with Bio-Oss or Bio-Oss mixed with autogenous bone as graft: a systematic review. Clin. Oral Impl. Res. 23, 2012; 263–273 doi: 10.1111/j.1600-0501.2011.02168.x

Tissue changes of extraction sockets in humans: a comparison of spontaneous healing vs. ridge preservation with secondary soft tissue healing.

Abstract: Introduction As a consequence of extraction, the height of the buccal wall tends to decrease and results in the disappearance of bundle bone. To modify bone remodelling after extraction, various ridge preservation techniques have been proposed. The present research was drawn up with the following considerations in mind: to evaluate and to compare changes of hard and soft tissues in post-extraction sockets which received a ridge preservation procedure, with post-extraction sockets which had healed naturally. Materials and methods Each patient was randomly allocated to a test or control group using a specific software package. After extraction, the sockets were carefully inspected and any granulation tissue was removed. The control sites received silk sutures to stabilize the clot without any grafting material. The test sites were grafted with corticocancellous porcine bone and a collagen membrane. All experimental sites had the membranes left exposed to the oral cavity with a secondary wound healing. The thickness of the buccal alveolar bone, if present, was carefully measured at the time of tooth extraction using a calliper at 1 mm from the edge of the wall. The following clinical parameters were evaluated at baseline and after 4 months at implant placement: vertical bone changes, horizontal bone changes and width of keratinized gingiva. The length, diameter and need for additional bone augmentation were assessed for both groups at the time of implant insertion. Results The control group showed vertical bone resorption of 1 ± 0.7 mm, 2.1 ± 0.6 mm, 1 ± 0.8 mm and 2 ± 0.73 mm at the mesial, vestibular, distal and lingual sites respectively. Moreover, changes in horizontal dimension showed an average resorption of 3.6 ± 0.72 mm. The test sites showed a horizontal bone remodelling of 0.3 ± 0.76 mm, 1.1 ± 0.96 mm, 0.3 ± 0.85 mm, 0.9 ± 0.98 mm at the mesial, vestibular, distal and lingual sites respectively. The horizontal bone resorption at the test sites was 1.6 ± 0.55 mm. The keratinized gingiva showed a coronal shift of 0.7 mm in the control group when compared to 1.1 mm in the test group. In addition, 42% of sites in the control group required an additional bone augmentation at implant placement, when compared to 7% in the test sites. Conclusions This study clearly points out that an alveolar ridge preservation technique performed with collagenated porcine bone and a resorbable membrane – according to the procedure reported in this study – was able to limit the contour changes after tooth extraction. Finally, the test sites showed a better preservation of facial keratinized tissue when compared to control sites; grafted sites allowed the placement of longer and wider implants when compared to implants inserted in non-grafted sites.

Occlusal overload and bone/implant loss

Abstract: Aim The aim of this search was to assess the biological consequences that overload might have on already osseointegrated oral implants through a systematic screening of the scientific literature. Method Detailed searches through PUBMED, OVID, EMBASE and LILACS databases were made. Articles published up to December 2011 and those reported on the clinical, radiographic and/or histological outcome of oral implants subjected to so-called overload were considered eligible for inclusion. Identified studies were assessed by one non-blinded reviewer according to well-defined inclusion and exclusion criteria. When doubt arose, the co-authors were counselled until final agreement was obtained. The PICO questions formulated was:“what is the effect of overload vs. no overload on bone/implant loss in clinically stable implants?” Results The database searches as well as additional hand searching, resulted in 726 potentially relevant titles. Eventually, 16 clinical and 25 animal studies were considered relevant to the topic. After inclusion/exclusion criteria assessment, all clinical studies and all but three animal studies and one systematic review were considered at high risk of bias and excluded. The included animal studies did not reveal an association between overload and peri-implant bone loss in the absence of peri-implant inflammation, whereas in its presence, overload seemed to aggravate the peri-implant tissue breakdown. Conclusions The effect of implant overload on bone/implant loss in clinically well-integrated implants is poorly reported and provides little unbiased evidence to support a cause-and-effect relationship. The PICO question remained unanswered. At the animal level, “overload”, mimicked by supra-occlusal contacts acting in an uninflamed peri-implant environment, did not negatively affect osseointegration and even was anabolic. In contrast, supra-occlusal contacts in the presence of inflammation significantly increased the plaque-induced bone resorption.

How successful are small-diameter implants? A literature review

Abstract: Background Edentulism is an important issue and will remain so due to high numbers of edentate individuals worldwide. For many years, complete dentures have been the only treatment option for this population. Implant overdentures have been shown to have many advantages over conventional complete dentures. However, although dissatisfied with their mandibular dentures, some edentate elders are reluctant to undergo even simple implant treatment due to factors such as cost and fear of surgery. To address these obstacles, this paper reports on a review of small-diameter implant (SDI) studies that were performed in the last two decades. The aim of this study is to (i) determine the survival of narrow diameter implants, (ii) determine whether survival is dependent on whether these implants are placed using a flap or flapless approach, and (ii) determine whether there is a relationship between length and implant survival in SDIs. Methods In this review, studies were included that (i) involve implants with 3.5 mm diameter or less, (ii) have a randomized clinical trial, retrospective or prospective cohort design with human subjects, (iii) provide a follow up duration of at least 5 months following implant placement, (iv) include data on the survival rate of the implants. Results Forty one studies meeting the above criteria were published between 1993 and 2011 using SDIs from a variety of companies and surface characteristics with diameters of 1.8 mm to 3.5 mm and lengths of 8 mm to 18 mm. A total of 10,093 SDIs were inserted in approximately 2762 patients. Twenty-six studies involved flap reflection techniques for implant placement, six studies used a flapless technique and two studies used both techniques; in the remaining studies, the technique was not specified. Follow up duration varied from 5 months to over 9 years. The survival rate reported in all screened studies was over 90%, including eight studies in which a 100% survival rate was reported. In 22 studies, the reported survival rate ranged from 95% to 99.9%. Failure was reported most often in short SDIs (less than or equal 13 mm) (n = 88) compared to longer ones (more than 13 mm). Conclusion Survival rates reported for SDI are similar to those reported for standard width implants. These survival rates did not appear to differ between studies that used flapless and flap reflection techniques. The failure rate appeared to be higher in shorter SDIs than in longer ones in the studies in which the length of the failed implants was reported. SDIs could be considered for use with fixed restorations and mandibular overdentures, since their success rate appears to be comparable to that of regular diameter implants. They might also be an efficient, low-cost solution for elders who wish to reduce problems with denture instability.

Relationship between the bone density estimated by cone-beam computed tomography and the primary stability of dental implants

Abstract: OBJECTIVES The aims of this study were to objectively assess bone quality with density values obtained by cone-beam computed tomography (CBCT) and to determine the correlations between bone density and primary stability of dental implants. MATERIAL AND METHODS Eighteen Straumann implants were inserted into 18 fresh femoral heads of swine. The bone densities of implant recipient sites were preoperatively determined by the density value using CBCT. The maximum insertion torque value of each implant was recorded using a digital torque meter. Resonance frequency, which represented a quantitative unit called the implant stability quotient (ISQ), was measured using an Osstell Mentor immediately after the implant placement. Spearman's correlation coefficient was calculated to evaluate the correlations among density values, insertion torques, and ISQs at implant placement. RESULTS The density values ranged from 98 to 902. The mean density value, insertion torque, and ISQ were 591 ± 226, 13.4 ± 5.2 Ncm, and 67.1 ± 8.1, respectively. Statistically significant correlations were found between the density values and insertion torque (r(s) =0.796, P<0.001), density values and ISQ (r(s) =0.529, P=0.024), and insertion torque and ISQ (r(s) =0.758, P<0.001). CONCLUSIONS The bone quality evaluated by specific CBCT showed a high correlation with the primary stability of the implants. Hence, preoperative density value estimations by CBCT may allow clinicians to predict implant stability. Whether the density values obtained by the CBCT device used in the present study could be applied to other devices requires further elucidation.

Anti-infective surgical therapy of peri-implantitis. A 12-month prospective clinical study

Abstract: The aim of this prospective cohort study was to evaluate an anti-infective surgical protocol for the treatment of peri-implantitis.