Management of the extraction socket and timing of implant placement: Consensus report and clinical recommendations of group 3 of the XV European Workshop in Periodontology.

BACKGROUND: The transition from a tooth requiring extraction to its replacement (with a dental implant) requires a series of clinical decisions related to timing, approach, materials, cost-effectiveness and the assessment of potential harm and patient preference. This workshop focused on the formulation of evidence-based consensus statements and clinical recommendations. METHODS: Four systematic reviews covering the areas of alveolar ridge preservation/bone grafting, immediate early and delayed implant placement and alveolar bone augmentation at the time of implant placement in a healed ridge formed the basis of the deliberations. The level of evidence supporting each consensus statement and its strength was described using a modification of the GRADE tool. RESULTS: The evidence base for each of the relevant topics was assessed and summarized in 23 consensus statements and 12 specific clinical recommendations. The group emphasized that the evidence base mostly relates to single tooth extraction/replacement; hence, external validity/applicability to multiple extractions requires careful consideration. The group identified six considerations that should assist clinicians in clinical decision-making: presence of infection, inability to achieve primary stability in the restoratively driven position, presence of a damaged alveolus, periodontal phenotype, aesthetic demands and systemic conditions. CONCLUSIONS: A substantial and expanding evidence base is available to assist clinicians with clinical decision-making related to the transition from a tooth requiring extraction to its replacement with a dental implant. More high-quality research is needed for the development of evidence-based clinical guidelines.

Guidelines for development of Implant Dentistry in the next 10 years regarding innovation, education, certification, and associations.

BACKGROUND: During the third Summer Camp of European Association of Osseointegration (EAO), 40 junior representatives from various European societies and associations were brought together to discuss and explore the following topics in Implant Dentistry in the next 10 years: (I) certification, (II) societies and associations, (III) continuing education, and (IV) innovations. AIMS: The aims of all working groups were to identify and outline the present situation in the area of the selected topic and to propose improvements and innovations to be implemented in the following 10 years. MATERIALS AND METHODS: Four different groups were assigned randomly to one of the four working units. The method to discuss the selected topics was World Cafè. The summaries of four topics were then given to all participants for peer review. RESULTS AND CONCLUSIONS: All four groups presented the conclusions and guidelines accordingly: (I) The recognition for Implant Dentistry and accreditation of training programs would lead to an improvement of the quality of care to the benefit of the patients; (II) Dental associations and societies have to continuously improve communication to meet needs of dental students, professionals, and patients (III) European Dental Board should be installed and become responsible for continue dental education; (IV) dental engineering, peri-implant diseases, and digital workflow in dentistry currently have limited tools that do not guarantee predictable results.

Digital technologies to support planning, treatment, and fabrication processes and outcome assessments in implant dentistry. Summary and consensus statements. The 4th EAO consensus conference 2015.

OBJECTIVE: The task of this working group was to assess the existing knowledge in computer-assisted implant planning and placement, fabrication of reconstructions applying computers compared to traditional fabrication, and assessments of treatment outcomes using novel imaging techniques. MATERIAL AND METHODS: Three reviews were available for assessing the current literature and provided the basis for the discussions and the consensus report. One review dealt with the use of computers to plan implant therapy and to place implants in partially and fully edentulous patients. A second one focused on novel techniques and methods to assess treatment outcomes and the third compared CAD/CAM-fabricated reconstructions to conventionally fabricated ones. RESULTS: The consensus statements, the clinical recommendations, and the implications for research, all of them after approval by the plenum of the consensus conference, are described in this article. The three articles by Vercruyssen et al., Patzelt & Kohal, and Benic et al. are presented separately as part of the supplement of this consensus conference.

Guided surgery: accuracy and efficacy.

Different computer-assisted implant-placement procedures are currently available. These differ in software, template manufacture, guiding device, stabilization and fixation. The literature seems to indicate that one has to accept a certain inaccuracy of ±2.0 mm, which seems large initially but is clearly smaller than for nonguided surgery. A reduction of accuracy to below 0.5 mm seems extremely difficult. A common shortcoming identified in the studies included in this review is inconsistency in how clinical data and outcome variables are reported. Another limitation is the small number of comparative clinical studies. In order to find the best guiding system or the most important parameters for optimal accuracy, more randomized clinical trials are necessary. Information on cost-effectiveness and patient-centered evaluations (i.e. questionnaires and interviews) must also be included.

Aetiology, microbiology and therapy of periapical lesions around oral implants: a retrospective analysis.

OBJECTIVE: The aim of this study was: (i) to evaluate whether an endodontic pathology on the extracted tooth or adjacent teeth of an implant site has an influence on the emergence of a periapical lesion, (ii) to retrospectively analyse the outcome of different treatment strategies, (iii) to determine which bacteria were present in periapical lesions. METHODS: The endodontic status of the tooth at the implant site and the adjacent teeth was explored and linked to the periapical status of the implant. For all the lesions treated since 2000, their survival was assessed. Finally, microbial samples (culturing) from the periapical lesions, were analysed. RESULTS: If an endodontic treatment or a periapical lesion at the apex of a tooth is present, a periapical lesion around the implant can be detected in 8.2% up to 13.6% (OR 7.2). For periapical pathology at the adjacent teeth, the percentage rises to 25% (OR 8.0). The best treatment option could not be found. Bacteria were found in 9/21 lesions. The most prominent species was P. gingivalis. CONCLUSIONS: When an endodontic pathology is present on the extracted or neighbouring teeth, it is significantly more likely that a periapical lesion will develop around a future implant.

RCT comparing implants with turned and anodically oxidized surfaces: a pilot study, a 3-year follow-up.

AIM: This 3-year prospective randomized controlled trial compared the clinical, microbiological and biochemical outcome of minimally (Turned, Tur) and moderately rough (TiUnite(®) , TiU) implant surfaces in a split-mouth design. MATERIAL AND METHODS: The study population included 14 subjects: nine fully edentulous and five partially edentulous subjects with a history of periodontitis. Implants (n = 78, 39 Tur and 39 TiU) were installed randomly in each patient. Peri-implant clinical parameters and intra-oral radiographs were recorded after 3 years of loading. Subgingival plaque and peri-implant crevicular fluid samples were collected and analysed using culture and quantitative polymerase chain reaction for the biofilm, and enzyme-linked immunosorbent assay for the concentration of osteoprotegerin and receptor activator of nuclear factor kappa-B ligand, respectively. RESULTS: No statistically significant differences in clinical, microbiological and biochemical parameters could be observed when comparing the Tur and TiU implant surfaces. CONCLUSION: After 3 years of loading, in periodontitis susceptible patients, the moderately rough, TiU implants demonstrated a similar clinical outcome compared with the smoother, turned implants. Longer follow-up and studies using different implant types are needed to confirm the statement that minimally and moderately rough implant surfaces perform similar, both from a clinical and from a microbiological point of view.

Microbial changes after full-mouth tooth extraction, followed by 2-stage implant placement.

BACKGROUND: Recent studies showed that qPCR could detect bacteria related to periodontitis and peri-implantitis in a low concentration after full-mouth tooth extraction. This study monitored the microbiota from tooth extraction, over 9 months of full edentulism, up to 1 year after abutment connection. MATERIAL AND METHODS: Ten patients with severe periodontitis were recruited. Six months after tooth extraction, implants were inserted. Three to 6 months later, they were connected to abutments. Plaque samples were collected from the tongue dorsum, saliva, and subgingival area (teeth/implants) before extraction up to 1 year after abutment connection, and analysed via culture, qPCR, and checkerboard technology. RESULTS: A reduction in the total amount of aerobic and anaerobic CFU/ml was observed. The concentration of Porphyromonas gingivalis and Tannerella forsythia (qPCR and checkerboard) in the saliva and, to a lower extent, on the tongue dorsum reduced. For Prevotella intermedia, changes were negligible and no changes could be detected for Aggregatibacter actinomycetemcomitans. The pristine subgingival niches were quickly colonized by key pathogens. Their final concentration remained low, while the detection frequencies remained very high over time. CONCLUSION: Complete edentulation results in a significant reduction of bacteria related to periodontitis and peri-implantitis, with the exception of A. actinomycetemcomitans, which might indicate that key pathogens can survive without pockets.

Characterisation of additional mental foramina through cone beam computed tomography.

Variations in jaw bone neurovascularisation must be identified to decrease the potential risk for haemorrhages and neural disturbances during surgical procedures such as implant placement and orthognatic surgeries. The aim of this study is to characterise additional mental foramina (AMF) through cone beam computed tomography (CBCT) images, by describing their frequency, size, location and direction of their associated bony canals, as well as to assess their corresponding ipsilateral and contralateral mental foramina (MF). CBCT images from 285 patients were analysed. Prevalence of AMF was 9·4%. From 0 to 2 AMF were observed, with two bilateral cases. Two cases of unilateral absence of MF were registered. Patients presenting AMF did not differ significantly from those without AMF regarding gender, age or ethnicity. Diameters of AMF and their corresponding ipsilateral and contralateral MF were 1·9 mm (±0·7 mm), 3·8 mm (±0·6 mm) and 4·1 mm (±0·6 mm), respectively. Ratios between diameters of AMF and corresponding ipsilateral MF ranged between 0·24 and 0·99. Location of AMF was variable, with most cases located posteriorly, posterior-inferiorly, posterior-superiorly or anterior-superiorly to their respective MF. Significant anatomical variability regarding neurovascularisation was observed among patients and CBCT examinations presented as a valuable tool for individually assessing these anatomical features.

A split-mouth comparative study up to 16 years of two screw-shaped titanium implant systems.

INTRODUCTION: Many studies have dealt with the clinical outcome of oral implants, yet none applied a randomized split-mouth design for a long-term follow-up of similar implant systems. AIM: To evaluate two oral implant systems with different surface characteristics in a randomized split-mouth design and to radiologically analyse peri-implant bone level and density over an up to 16-year period. MATERIALS AND METHODS: The study comprised clinical and radiographic records of 18 partially edentulous patients treated with both implant types randomly placed in either left or right jaw sides. Outcome was evaluated over time. RESULTS: Clinical and radiographic parameters showed no significant differences over time for both systems. Ten years after implant placement, a significantly increasing peri-implant bone density was noted, while Periotest values were found to be significantly decreasing. Fifteen years after implant loading, mean bone loss was 0.02 mm (range -1.15 to 1.51; SD 0.45) for Astra Tech® implants (n=24) and 0.31 mm (range -0.98 to 2.31; SD 0.69) for Brånemark® implants (n=23). CONCLUSIONS: The study failed to demonstrate significant differences in the outcome of the peri-implant bone for two implant systems with different surface characteristics. The marginal bone level around oral implants changed <0.5 mm after 15 years of loading.

Relationship between cortical bone thickness or computerized tomography-derived bone density values and implant stability.

AIMS: To explore the relationship between primary implant stability and different parameters related to implant or bone properties. MATERIALS AND METHODS: Twenty-four patients received a total of 136 Straumann SLActive implants. Resonance frequency analysis (RFA) was performed at implant placement, and RFA and Periotest (PTV) were scored at loading. Bone density [Hounsfield (HU) scores] and coronal cortical thickness at osteotomy sites were measured from pre-operative computerized tomography scans. RESULTS: Implant length, diameter or the presence of bony dehiscence did not have a significant effect on the mean RFA scores at implant insertion. Significant linear relations were found between RFA or PTV scores and HU values (P<0.05), or cortical bone thickness (P<0.05), both at insertion as well as at loading. CONCLUSION: RFA and PTV scores can be predicted based on implant and especially bone related factors.

Do periodontopathogens disappear after full-mouth tooth extraction?

AIM: To monitor the intra-oral microbiological changes after full-mouth extraction using quantitative polymerase chain reaction (qPCR). MATERIAL AND METHODS: Nine patients with severe, aggressive periodontitis, for whom a full-mouth tooth extraction was the only remaining treatment option were recruited. Before and 6 months after extraction, microbial samples were obtained (tongue, saliva and subgingival plaque) and analysed by qPCR. RESULTS: The elimination of subgingival niches, by extraction of all natural teeth, resulted in a 3-log reduction of Porphyromonas gingivalis and Tannerella forsythia, and more modest reductions of Aggregatibacter actinomycetemcomitans and Prevotella intermedia. However, the detection frequencies of these periodontopathogens in saliva and on the tongue remained unchanged after full-mouth tooth extraction. CONCLUSION: In contrast to what has been believed so far, full-mouth tooth extraction does not result in eradication of all periodontopathogens but only in a significant reduction. The clinical consequences of this observation remain speculative.

Correlation between early perforation of cover screws and marginal bone loss: a retrospective study.

AIM: This retrospective study aimed to determine the consequence of early cover screw exposure on peri-implant marginal bone level. MATERIAL AND METHODS: Sixty Astra Tech MicroThread implants installed in partially edentulous jaws were compared: 20 implants were placed following a two-stage procedure and were unintentionally exposed to the oral cavity (two-stage exposed), 20 implants were placed following a two-stage procedure and were surgically exposed after a subgingival healing time of 3-6 months (two-stage submerged), and 20 implants were placed following a one-stage surgical protocol (one-stage). Digital radiographs were taken at implant placement for all implants, and after abutment surgery for the two-stage exposed and two-stage submerged groups or after 3 months for the one-stage group. Bone loss mesially and distally was measured with an on-screen cursor after calibration. RESULTS: Mean bone re-modelling was 1.96 mm (range: 0.2-3.2 mm) around the two-stage exposed implants, 0.01 mm (range: 0.0-0.3 mm) around the two-stage submerged implants and 0.14 mm (range: 0.0-1.2 mm) around the one-stage implants. CONCLUSION: The unintentional perforation of two-stage implants resulted in significant bone destruction, probably because the biological width was not considered.

How does the timing of implant placement to extraction affect outcome?

PURPOSE: To systematically review the current literature on the clinical outcomes and incidence of complications associated with immediate implants (implants placed into extraction sockets at the same surgery that the tooth is removed) and early implants (implants placed following soft tissue healing). MATERIALS AND METHODS: A MEDLINE search was conducted for English papers on immediate/early placement of implants based on a series of search terms. Prospective as well as retrospective studies (randomized/nonrandomized clinical trials, cohort studies, case control studies, and case reports) were considered, as long as the follow-up period was at least 1 year of loading and at least 8 patients and/or at least 10 implants had been examined. Screening and data abstraction were performed independently by 3 reviewers. The types of complications assessed were implant loss; marginal bone loss; soft tissue complications, including peri-implantitis; and esthetics. RESULTS: The initial search provided 351 abstracts, of which 146 were selected for full-text analysis. Finally, 17 prospective and 17 retrospective studies were identified, with observation times generally between 1 and 2 years for the prospective studies and around 5 years for the retrospective studies. The heterogeneity of the studies (including postextraction defect characteristics, surgical technique with or without membrane and/or bone substitute, implant location in socket, inclusion and exclusion criteria, and prosthetic rehabilitation), however, rendered a meta-analysis impossible. Most papers contained only data on implant loss and did not provide useful information on failing implants or on hard and soft tissue changes. In general, the implant loss remained below 5% for both immediate and early placed implants (range, 0% to 40% for immediate implants and 0% to 9% for early placed implants), with a tendency toward higher losses when implants were also immediately loaded. CONCLUSION: Because of the lack of long-term data, questions regarding whether peri-implant health, prosthesis stability, degree of bone loss, and esthetic outcome of immediate or early placed implants are comparable with implants placed in healed sites remain unanswered.

Effect of material characteristics and/or surface topography on biofilm development.

BACKGROUND: From an ecological viewpoint, the oral cavity, in fact the oro-pharynx, is an 'open growth system'. It undergoes an uninterrupted introduction and removal of both microorganisms and nutrients. In order to survive within the oro-pharyngeal area, bacteria need to adhere either to the soft or hard tissues in order to resist shear forces. The fast turn-over of the oral lining epithelia (shedding 3 x/day) is an efficient defence mechanism as it prevents the accumulation of large masses of microorganisms. Teeth, dentures, or endosseous implants, however, providing non-shedding surfaces, allow the formation of thick biofilms. In general, the established biofilm maintains an equilibrium with the host. An uncontrolled accumulation and/or metabolism of bacteria on the hard surfaces forms, however, the primary cause of dental caries, gingivitis, periodontitis, peri-implantitis, and stomatitis. OBJECTIVES: This systematic review aimed to evaluate critically the impact of surface characteristics (free energy, roughness, chemistry) on the de novo biofilm formation, especially in the supragingival and to a lesser extent in the subgingival areas. METHODS: An electronic Medline search (from 1966 until July 2005) was conducted applying the following search items: 'biofilm formation and dental/oral implants/surface characteristics', 'surface characteristics and implants', 'biofilm formation and oral', 'plaque/biofilm and roughness', 'plaque/biofilm and surface free energy', and 'plaque formation and implants'. Only clinical studies within the oro-pharyngeal area were included. RESULTS: From a series of split-mouth studies, it could be concluded that both an increase in surface roughness above the R(a) threshold of 0.2 microm and/or of the surface-free energy facilitates biofilm formation on restorative materials. When both surface characteristics interact with each other, surface roughness was found to be predominant. The biofilm formation is also influenced by the type (chemical composition) of biomaterial or the type of coating. Direct comparisons in biofilm formation on different transmucosal implant surfaces are scars. CONCLUSIONS: Extrapolation of data from studies on different restorative materials seems to indicate that transmucosal implant surfaces with a higher surface roughness/surface free energy facilitate biofilm formation.

Randomized controlled trial to compare two bone substitutes in the treatment of bony dehiscences.

AIM: This in vivo split-mouth randomized controlled trial compared a synthetic bone substitute with a bovine bone mineral to cover bone dehiscences after implant insertion. MATERIALS AND METHODS: Fourteen patients received four to six implants to support an overdenture. Two comparable dehiscences within the same patient were first covered with a layer of autogenous bone, followed by a layer of either Bio-Oss® (group 1; Geistlich Pharma AG, Wolhusen, Switzerland) or Straumann BoneCeramic® (group 2; Institut Straumann AG, Basel, Switzerland) and sealed by a resorbable membrane. The change in vertical dimension of the defect was measured at implant placement and at abutment connection (6.5 months). Clinical and radiological parameters were evaluated up to 1 year of loading. RESULTS: The vertical size of the defect at surgery was 6.4 ± 1.6 mm for group 1 and 6.4 ± 2.2 mm for group 2 sites, measured from the implant shoulder. After 6.5 months, the depth of the defect was reduced to 1.5 ± 1.2 mm and 1.9 ± 1.2 mm for group 1 and group 2 sites, respectively (p > 0.05). No implants failed during follow-up. Mean marginal bone loss over the SLActive surface was 0.94 mm (group 1), 0.81 mm (group 2), and 0.93 mm (group 3, no dehiscence) after 1 year of loading. CONCLUSION: Both bone substitutes behaved equally effectively.

Microbiological outcome of two screw-shaped titanium implant systems placed following a split-mouth randomised protocol, at the 12th year of follow-up after loading.

PURPOSE: To compare the subgingival microbiota around two differently designed implant systems that were in function for more than 12 years in a randomised split-mouth study design, and to compare the outcome with natural dentition. MATERIALS AND METHODS: A total of 18 partially edentulous patients received at least two TiOblast™ (Astra Tech) and two Brånemark (Nobel Biocare) implants following a split-mouth design. At the last follow-up visit, periodontal parameters (probing depth, bleeding on probing and plaque) were recorded and intraoral radiographs were taken to calculate bone loss. Subgingival plaque samples were collected for culture, qPCR and checkerboard DNA-DNA hybridisation analysis. These data were related to implant design and bone loss. This study setup allowed a comparison of 34 Astra Tech (Impl A) with 32 Brånemark (Impl B) implants. RESULTS: During the 12-year follow up, five patients dropped out. One Brånemark implant was lost before abutment connection in a dropout patient. Mean bone loss between loading and year 12 was 0.7 mm (range: -0.8-5.8) (Impl A), and 0.4 mm (range: -1.1-4.1) (Impl B). No significant microbiological differences (qualitative and quantitative) could be observed between both implant types. Compared to teeth, subgingival plaque samples from implants did not reach the concentration of pathogens, even after 12 years of function. CONCLUSIONS: These data show that both implant systems (with differences in macro-design and surface characteristics), in patients with good oral hygiene and a stable periodontal condition, can maintain a successful treatment outcome without significant subgingival microbiological differences after 12 years of loading. The presence of periodontopathogens did not necessarily result in bone loss.

Impact of supportive periodontal therapy and implant surface roughness on implant outcome in patients with a history of periodontitis.

OBJECTIVE: This review searched for a relationship between susceptibility to periodontitis and peri-implantitis, with implant outcome as the primary outcome variable and supportive periodontal therapy (SPT) and implant surface roughness as confounding factors. MATERIAL AND METHODS: It is based on a MEDLINE search up to June 2006. Only 16 fulfilled the selection criteria. The heterogeneity of the studies (e.g. periodontal status, SPT, prosthetic design, ...) rendered a meta-analysis impossible. The impact of a history of periodontitis on early implant loss was negligible. Only five papers reported sub-data for patients with different degrees of periodontitis. Four out of five papers indicate a higher incidence of late implant loss and/or marginal bone loss in patients with a history of periodontitis. This difference was most obvious for very rough implants (three papers), and/or when SPT was not organized (one paper). Other confounding factors were often neglected. Another 10 papers only reported the outcome of implants in patients with a history of periodontitis. In case of SPT and when avoiding roughened surfaces, late implant loss remained below 3%, and marginal bone loss remained low. CONCLUSIONS: These results seem to indicate that periodontally compromised patients can be successfully treated with minimally/moderately rough implants, in the presence of SPT.