Consensus Statements and Recommended Clinical Procedures Regarding Risk Factors in Implant Therapy

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1 Consensus Statements and Recommended Clinical Procedures Regarding Risk Factors in Implant Therapy David L. Cochran, DDS, MS, PhD, MMSci 1 /Søren Schou, DDS, PhD, Dr Odont 2 / Lisa J. A. Heitz-Mayfield, BDS, MDSc, Dr Odont 3 /Michael M. Bornstein, Dr Med Dent 4 / Giovanni E. Salvi, PD, Dr Med Dent 5 /William C. Martin, DMD, MS 6 INTRODUCTORY REMARKS This group was asked to address the available evidence for potential risk factors in implant therapy. The authors were requested to prepare narrative reviews using a systematic approach, and were provided with general topics rather than specific research questions. The four reviews presented for discussion within the group addressed: (1) systemic conditions and treatments as risks for implant therapy, (2) history of treated periodontitis and smoking as risks for implant therapy, (3) mechanical and technical risks in implant therapy, and (4) local risk factors for implant therapy. 1 Professor and Chair, Department of Periodontics, The University of Texas Health Science Center at San Antonio Dental School, San Antonio, Texas, USA. 2 Professor and Chairman, Department of Oral and Maxillofacial Surgery and Oral Pathology, School of Dentistry, Aarhus University, Århus, Denmark. 3 Professor, Centre for Rural and Remote Oral Health, The University of Western Australia, Crawley, WA, Australia. 4 Assistant Professor, Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland. 5 Vice Chairman and Graduate Program Director, Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland. 6 Clinical Associate Professor, Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, Gainesville, Florida, USA. Correspondence to: Prof David L. Cochran, Department of Periodontics, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MSC 7894, San Antonio, TX , USA. Fax: cochran@ uthscsa.edu These statements are part of the Proceedings of the Fourth ITI Consensus Conference, sponsored by the International Team for Implantology (ITI) and held August 26 28, 2008, in Stuttgart, Germany. The group s participants critically reviewed each of the review papers produced by its members, and amendments were made following thorough discussion. The included papers, general conclusions, clinical recommendations, and recommendations for future research were determined by group consensus and following acceptance at plenary sessions. Risk To identify a true risk factor, causality must be established, requiring prospective longitudinal studies. In the four reviews included, the term risk refers to a factor which is associated with the outcomes of implant therapy. It was noted that few risk factors were evaluated as independent variables. In addition, there was inconsistency in reporting of and adjustment for confounding factors. Within each review, considerable heterogeneity among included studies in terms of definitions of patient population and outcome variables was found. There was a wide range in the level of evidence available among the different review papers, ranging from case series to systematic reviews. The group felt that the possibility of publication bias leading to an overestimation of success could be a specific problem where evidence was in the form of case series and reports. In the selected studies, a distinction between different implant designs, implant surfaces, operator experience, and precision of the prosthetic restoration was rarely reported. In general, the evolution of implant dentistry is such that implants currently used are not necessarily those evaluated in the included studies. Many potential risk factors may never be evaluated due to the difficulty in conducting appropriate studies and for ethical reasons. Disclosure None of the participants in this group reported a conflict of interest. 86 Volume 24, Supplement, 2009

2 SYSTEMIC CONDITIONS AND TREATMENTS The aim of this review was to assess various systemic conditions and their treatments as risk factors for implant therapy. Many patients who may benefit from implant placement present with concomitant systemic diseases. For many systemic diseases, there are no reports on the use of oral implants. The largest amount of information exists for diabetes mellitus, osteoporosis, and radiotherapy. Most of the information is in the form of case reports and case series. The possibility of publication bias, leading to an overestimation of success, needs to be considered, and this is a major problem of case reports and case series. The published literature does not allow distinguishing between subtypes of systemic diseases, such as diabetes mellitus type 1 and 2, or primary and secondary osteoporosis. Patients may present with multiple risks that may be interrelated, making the estimation of the impact of a single factor difficult. With respect to systemic conditions and treatments as risk factors for implant therapy, the following recommendations can be made: A thorough medical history is essential to identify potential systemic risks. Risks for implant failure and risks for medical complications should be differentiated and evaluated. In some instances, conditions and their treatments may pose increased risks for implant failure, whereas the risk for the patient may be minimal. As an example, there are no data to support withholding implant treatment for patients with diabetes or osteoporosis. However, these patients need to be informed of the possibility of implant complications. Where there is a potential risk of a medical complication for example, osteonecrosis of the jaw in patients taking oral bisphosphonates and patients undergoing radiotherapy the option of implant therapy should be chosen restrictively, and the patient should be informed specifically, taking into account the current level of uncertainty with regard to the consequences. For patients with a life-threatening systemic disease, implant placement should be postponed until the patient s medical condition is stabilized and has improved. Well-designed prospective, controlled clinical trials are needed in subjects with systemic diseases, especially common chronic diseases. The medical diagnosis, status, comorbidities, and treatments should be reported in detail. With regards to diabetes, assessment of glycemic control should be included. Studies addressing implants placed in patients taking oral bisphosphonates should record the type of the drug, its dosage, and the duration of therapy. Regarding rare and uncommon systemic conditions, clinicians are encouraged to report complications with implant therapy. HISTORY OF TREATED PERIODONTITIS AND SMOKING The aim of this paper was to evaluate cigarette smoking and a history of treated periodontitis, both alone and combined, as risk factors for adverse implant outcomes. Considerable heterogeneity among studies was found, making comparisons of outcomes difficult. The definitions of periodontitis and nonperiodontitis patients differed among studies. Where a description of the type of periodontitis was given, the type of periodontal disease was usually described as chronic periodontitis. While all studies reported that periodontal patients were treated, and the majority of studies reported regular supportive periodontal therapy, the periodontal status was infrequently reported. A range of definitions for smokers, nonsmokers, and former smokers were used in the studies. Few studies reported and adjusted for confounding factors. The outcomes addressed in this review were implant survival, implant success (as defined by the authors), longitudinal radiographic bone levels, and occurrence of peri-implantitis. History of Treated Periodontitis. Three controlled studies reported statistically significantly lower implant survival rates in patients with a history of periodontitis compared to nonperiodontal patients. However, the majority of studies report high implant survival rates (> 90%). There is evidence that patients with a history of periodontitis are at greater risk for peri-implantitis than patients without a history of periodontitis (reported odds ratios ranged from 3.1 to 4.7). The International Journal of Oral & Maxillofacial Implants 87

3 Cochran et al Smoking. There is strong evidence that smoking is a risk factor for adverse implant outcomes. The evidence shows that smokers have an increased risk of peri-implantitis (reported odds ratios ranged from 3.6 to 4.6) and radiographic marginal bone loss (reported odds ratios ranged from 2.2 to 10) compared to nonsmokers. There is some evidence for a dose effect of cigarette smoking. History of Treated Periodontitis and Smoking Combined. There are few studies evaluating the combined effect of smoking and a history of periodontitis. There is some evidence of an increased risk for implant failure and bone loss in smokers with a history of treated periodontitis compared to nonsmokers with a history of treated periodontitis. With respect to a history of treated periodontitis and smoking, the following recommendations can be made: History of Treated Periodontitis. A history of treated periodontitis is not a contraindication for implant placement. However, patients with a history of treated periodontitis should be informed of an increased risk of implant failure and periimplantitis. Patients with a history of periodontitis should receive individualized periodontal maintenance and regular monitoring of peri-implant tissue conditions. Smoking. Smoking is not a contraindication for implant placement. However, patients should be informed that the survival and success rates are lower in smokers. Heavy smokers should be informed that they are at greater risk of implant failure and loss of marginal bone. Patients who smoke should be informed that there is an increased risk of implant failure when sinus augmentation procedures are used. History of Treated Periodontitis and Smoking Combined. Patients who smoke and have a history of treated periodontitis should be informed that they have an increased risk of implant failure and peri-implant bone loss. The impact of the patient s periodontal status at the time of implant placement on implant outcomes needs to be evaluated. A uniform definition of treated periodontitis should be established. The effect of maintaining a periodontally involved tooth on the potential for future implant placement should be assessed. Smoking habits including information on the exposure, dose, and duration should be recorded in future studies of implant survival and success. A uniform definition of a smoker, former smoker, and nonsmoker in relation to implant therapy should be established for future studies. Implant failures need to be differentiated according to the time of occurrence, since the pathogenic mechanisms are different. Studies evaluating the effect of smoking cessation protocols are needed. The combined effect of a history of periodontitis and smoking on implant outcomes needs to be further investigated. MECHANICAL AND TECHNICAL RISKS The review addressing mechanical/technical risks in implant therapy was based solely on controlled studies (ie, with or without exposure to the mechanical/ technical risks). In terms of the quantity of the evidence, for each of the 10 identified mechanical/technical risks, a wide range in the number of included publications was found (eg, between 1 and 14). In terms of the quality of the evidence, the level of evidence ranged from randomized clinical trials to prospective and retrospective cohort studies. A standardized classification of prosthetic complications is lacking. With respect to mechanical/technical risks, the following recommendations can be made: In general, implant reconstructions should be planned to minimize mechanical/technical risks. Patients receiving implant therapy should receive regular maintenance care in order to detect mechanical/technical complications early, particularly in patients with overdentures. Both cemented and screw-retained implant-supported reconstructions can be recommended. Patients should be evaluated for bruxism. Future clinical studies should include detailed listings of the incidence and the frequency of mechanical complications/failures of components, as well as the incidence and the frequency of technical complications/failures of laboratory-fabricated suprastructures or their materials. 88 Volume 24, Supplement, 2009

4 Patient-based and reconstruction-based rates of mechanical and technical complications/failures over a specified time period should be assessed in future studies. Laboratory procedures should be better delineated. The development of devices to measure clinical functional/parafunctional loading of components and laboratory-fabricated suprastructures should be encouraged. The development of materials for components and laboratory-fabricated suprastructures with improved mechanical properties should be encouraged. Studies should be designed to critically evaluate the role of the mechanical/technical risks listed in the present review. LOCAL RISK FACTORS The aim of the review was to assess the influence of various local risk factors on the outcome of implant therapy. Limited data (two prospective clinical trials) exist evaluating the available interdental space as a risk factor for implant survival. Two clinical studies (both prospective clinical trials) show that as the proximity of the implant to the neighboring tooth decreases (< 3 mm), the proximal bone loss on adjacent teeth could increase following implant placement. There is evidence examining the placement of dental implants into infected sites exhibiting apical pathology. Two clinical trials (one randomized clinical trial, one prospective randomized trial) have shown survival rates greater than 92% after 1 year when the implants were placed in debrided sockets and with primary stability. There is no evidence supporting soft tissue thickness as a risk factor in implant survival. While the secondary outcome of gingival recession is important, there was no significant correlation with tissue thickness and recession around dental implants (one retrospective clinical study). In a recent systematic review, methods of bone density and implant stability assessment were not validated and therefore cannot be linked with implant survival. With respect to local risk factors, the following recommendation can be made: Special care should be taken in selection of implant diameter and design in areas with limited interdental space. Recommended Topics for Future Research The effect of implant malposition The effect of soft tissue thickness on mucosal recession The International Journal of Oral & Maxillofacial Implants 89

Consensus Statements and Recommended Clinical Procedures Regarding Loading Protocols

Group 3 Consensus Statements Consensus Statements and Recommended Clinical Procedures Regarding Loading Protocols Hans-Peter Weber, DMD, Dr Med Dent 1 /Dean Morton, BDS, MS 2 /German O. Gallucci, DMD,