Incidence and primary prevention of complications related to the placement of dental implants

Despite high success rate with endosseous titanium implants, failures inevitably occur. At an early stage, lack of primary stability, surgical trauma, peroperative contamination and occlusal overload seem to be the most important causes of implant failure. Many authors have reported that implant failures after primary healing and osseointegration are mainly due to peri-implant infection and/or excessive occlusal stress. Like periodontal disease, peri-implant inflammatory lesions develop as a result of plaque accumulation and exhibit similar clinical and microbiological signs as encountered for periodontitis. Clinicians should therefore enforce preventive measures to decrease the prevalence of such causative agents. Therapeutic attempts should have their rationale in the restoration of a biomechanical and/or host-bacterial equilibrium. The major limitation at this point seems to be the detection of a pathological process. Aside from clinical evaluation, the interpretation of radiographic images is one of the most frequently applied diagnostic procedures in patients with osseointegrated implants. Post-therapeutic maintenance care is an integral part of the entire implant treatment approach.     

One-year follow-up of an implant with early radiographic signs of loss of osseointegration: case report

Background: Failures in dental implant treatment are classified as early and late and depend on certain complications. Proposed preventions and treatment modalities for late complications have been comprehensively reviewed in the literature. Since early implant failures are characterized by lack of Osseointegration, generally, removal of the implant is suggested to prevent extensive bone loss that would further complicate implant placements in future. Purpose: This case report presents the controversy between clinical findings and radiographic examinations in evaluating the nature of contact between an implant surface and the bone during the healing period. Materials and Methods: In one patient scheduled for implant treatment in both jaws, four maxillary and two mandibular implants showed excellent healing, whereas one mandibular implant showed an extensive radiolucent area indicating early failure after 6 weeks of healing. The latter implant was clinically stable and was not removed. Results: Radiographic evaluation 1 year later showed no sign of peri‐implant radiolucency of the mandibular Implant as seen after primary healing. Conclusion: When the bone‐implant interface appears to be compromised radiographically but not clinically, such implants may have a favorable prognosis through a currently unknown biologic host response.     

54颗种植体早期失败原因分析及影响因素研究

目的    分析种植体早期失败原因及可能的影响因素，提高对种植预后的预测性，为临床减少种植体失败提供理论依据。方法    选择中国医科大学附属口腔医院种植中心2005年1月至2017年12月种植体早期失败病例，分析其失败原因并评价与种植体早期失败相关的患者自身、种植体及外科手术因素。结果    自2005年1月至2017年12月，共7250例患者于我科接受种植修复治疗，共计植入种植体11 534颗。截至2018年3月底，明确记录的早期失败患者有47例，共计脱落54颗种植体，其早期失败率为0.47%。在单因素分析中有统计学意义的影响因素分别是性别、种植部位、缺牙原因、缺牙区骨密度、种植体长度、是否行骨挤压术及上颌窦外侧壁开窗术（P < 0.05）。结论    种植体早期失败主要由骨结合不良所致，而经单因素分析提示与其相关的因素多为患者自身因素及外科手术因素。故在临床上应严格筛选适应证，对于高风险者术前应给予充分交代；在手术过程中应严格遵守手术规则，根据患者缺失牙的具体情况来制定个性化的手术方案，选择合适的附加手术，尽可能将种植体失败的风险降到最低。     

Dental implant design and oral and systemic health

Dental implants are now a common treatment for replacing missing teeth, and their success has long been measured by appearance, function, and longevity of placement. Most dental implants provide a natural-looking appearance. However, both patients and dentists should be aware that infectious complications of dental implants may not only affect function and longevity, but also the systemic health of patients. In addition to traditional measures of success, numerous published studies support, as a key outcome, prevention of implants from harboring periodontal pathogens. Known negative outcomes of infection include failure of the implant to integrate with the bone, causing implant loss and possible bone loss. Given the established associations between periodontitis and systemic health, it is possible that infection in and around the implant components may impart risks to systemic health. This article reviews causes for peri-implant infection and implant loss, and evaluates an implant design that decreases the possibility of infection and possible health complications, by preventing bacterial infiltration.     

Early outcome of an implant system with a resorbable adhesive calcium–phosphate coating—a prospective clinical study in partially dentate patients

This study aims to investigate the early outcome of a dental implant with bioactive calcium-phosphate (CaP) coating in the first year of usage in different clinical indications in partially edentulous patients, after early and delayed prosthetic loading. Therefore, in a prospective follow-up study, the cumulative survival and success rate of a conical, self-drilling and self-tapping implant system after 6 months and 1 year post-insertion was evaluated. A total of 311 CaP-coated implants were placed in 124 patients. Seventy-two implants in clinical high-quality bone situation were loaded after 2 weeks post-insertion with the definite restoration; the rest after 6 months. The indication for implant placement was treatment of partial dentate mandible and maxilla. One hundred sixty-three implants were placed in the posterior mandible, 117 in the posterior maxilla. In the frontal maxilla, 25 implants and in the frontal mandible, eight implants were used. In 126 cases (36%), bone augmentation procedures (guided bone regeneration and sinus lift) were performed concomitant with implant placement. The difference between primary and secondary stability (implant stability quotient (ISQ), Periotest, insertion torque), peri-implant clinical parameter as well as survival and success criteria were evaluated. In total, ISQ mean values after 6 months were higher than after implant placement. Periotest values increased in the period of the first 6 months and remained constant afterwards. After 6 months of insertion, the mean bone loss was 0.051 mm. After 12 months, a bone gain with a mean of +0.016 mm was observed; implants in the posterior maxilla showed significant less bone resorption than implants in the posterior mandible (p < 0.0001). In the most of the implants (74%), clinical normal gingival tissue could be observed. In 24%, a mild inflammation was analysed. In 35 implants, a provocation of peri-implant bleeding was possible. In the early loading group, no implant failure was seen. Altogether, one implant in D4 bone has been lost. The cumulative survival rate summed up to 99.7%. In general, implant success assessment analysis according to Albrektsson and Buser displayed success in 99.7% of the implants. With respect to the patient selection including 124 implants with minor and major augmentations as well as early loading prosthetic function, the 1-year clinical use of the studied implant system with CaP coating showed good results, comparable to that of conventional implants without a specific coating. After 1 year, neither special disadvantages nor benefits of CaP-coated implants could be evaluated. Long-term results are further needed.     

Occlusal considerations in implant therapy: clinical guidelines with biomechanical rationale

Due to lack of the periodontal ligament, osseointegrated implants, unlike natural teeth, react biomechanically in a different fashion to occlusal force. It is therefore believed that dental implants may be more prone to occlusal overloading, which is often regarded as one of the potential causes for peri-implant bone loss and failure of the implant/implant prosthesis. Overloading factors that may negatively influence on implant longevity include large cantilevers, parafunctions, improper occlusal designs, and premature contacts. Hence, it is important to control implant occlusion within physiologic limit and thus provide optimal implant load to ensure a long-term implant success. The purposes of this paper are to discuss the importance of implant occlusion for implant longevity and to provide clinical guidelines of optimal implant occlusion and possible solutions managing complications related to implant occlusion. It must be emphasized that currently there is no evidence-based, implant-specific concept of occlusion. Future studies in this area are needed to clarify the relationship between occlusion and implant success.     

The causes of early implant bone loss: myth or science?

The success of dental implants is highly dependent on integration between the implant and intraoral hard/soft tissue. Initial breakdown of the implant-tissue interface generally begins at the crestal region in successfully osseointegrated endosteal implants, regardless of surgical approaches (submerged or nonsubmerged). Early crestal bone loss is often observed after the first year of function, followed by minimal bone loss (< or =0.2 mm) annually thereafter. Six plausible etiologic factors are hypothesized, including surgical trauma, occlusal overload, peri-implantitis, microgap, biologic width, and implant crest module. It is the purpose of this article to review and discuss each factor Based upon currently available literature, the reformation of biologic width around dental implants, microgap if placed at or below the bone crest, occlusal overload, and implant crest module may be the most likely causes of early implant bone loss. Furthermore, it is important to note that other contributing factors, such as surgical trauma and penimplantitis, may also play a role in the process of early implant bone loss. Future randomized, well-controlled clinical trials comparing the effect of each plausible factor are needed to clarify the causes of early implant bone loss.     

Effects of smoking on the outcome of implant treatment: a literature review.

STATEMENT OF PROBLEM: The use of osseointegrated implants as a foundation for the prosthetic replacement of missing teeth has become widespread in the last decade. Owing to the remarkable success of dental implants, there has been growing interest in identifying the factors associated with implant failure. Given the well-documented deleterious effect of smoking on wound healing after tooth extraction and its association with poor quality bone and periodontal disease, a negative effect of tobacco use on implant success is to be expected. PURPOSE: To establish the relationship between smoking and implant-related surgical procedures (i.e, sinus lift procedures, bone grafts and dental implants), including the incidence of complications related to these procedures and the long-term survival and success rates of dental implants among smokers and nonsmokers based on relevant literature.MATERIALS AND METHODS: Relevant clinical studies published in English between 1990 and 2006 were reviewed. The articles were located through Medline and, manually, through the references of peer-reviewed literature. This was supplemented with a hand search of selected dental journals and text books.RESULTS: The majority of the past and current literature implicates smoking as one of the prominent risk factors affecting the success rate of dental implants with only a handful of studies failing to establish a connection. Most of the studies report the failure rate of implants in smokers as being more than twice that in nonsmokers. These findings are difficult to ignore. There is a statistically significant difference between smokers and nonsmokers in the failure rates of dental implants. Smoking also has a strong influence on the complication rates of implants: it causes significantly more marginal bone loss after implant placement, it increases the incidence of peri-implantitis and affects the success rates of bone grafts. The failure rate of implants placed in grafted maxillary sinuses of smokers is again more than twice that seen in nonsmokers.Conclusion: Smokers have higher failure rates and complications following dental implantation and implant-related surgical procedures. The failure rate of implants placed in grafted maxillary sinuses of smokers is more than twice that seen in nonsmokers.     

Risk factors associated with early failure of dental implants. A literature review

The aim of the study was to examine articles published on risk factors associated with early failure of dental implants. We conducted a search on PubMed for articles published between January 2000 and December 2009 using the keywords 'dental implants' and 'early failure'. Seven studies that specified the number of early failed implants and studied the associated risk factors were included. Early failures are caused by the inability of tissue to establish osseointegration prior to prosthetic restoration; however the causal factors and mechanisms are unclear. In the reviewed literature there was a higher percentage of early than late failures; nevertheless, few articles were found that analyzed risk factors associated with early implant failure. In the majority of studies, statistically significant factors associated with early implant failure were smoking, quantity and quality of bone, and posterior implant location. The low number of studies in the literature does not allow definitive conclusions to be drawn.     

Dental implant success-failure analysis: a concept of implant vulnerability

This article shows the factors of importance in the long-term success and failure of oral implants based on literature review. Many factors are attributed to the failure of dental implants. The critical components leading to early and late implant failures are evaluated. The behavior of natural teeth and implants is compared in healthy and unfavorable local and systemic conditions. Similarities and differences among dental implants, healthy natural teeth, and ankylosed teeth are examined. Based on this comparison, the author attempts to draw a conclusion on the vulnerability of dental implants and their prognosis. The importance of ongoing clinical supervision of a patient's implant condition with a good recall program and the necessity to accumulate clinical data concerning implant failures over an extended period of time in a standardized manner are emphasized. It is also suggested that implant practitioners avoid giving guarantees of long-term implant success to their patients.     

Histopathologic observations on late oral implant failures

Background: Despite good success rates of osseointegrated oral implants, failures do occur. To minimize losses, failure mechanisms should be elucidated. Purpose: This study sought to describe the morphology of tissues surrounding late failed Brånemark implants in relation to their clinical and radiographic findings to acquire a better understanding of the etiologic factors. Material and Methods: Ten failed implants and their surrounding tissues were consecutively retrieved from nine patients after prosthesis placement (late losses). On radiographs, a radiolucent line was visible around nine clinically mobile implants. Tightening of the abutment screw evoked pain at seven mobile implants. Clinically, no other visual inflammatory sign or symptom was manifest. A fistula originated from one stable implant, surrounded on radiographs by a diffuse bone rarefaction. Retrieved implants were electrochemically dissolved. Intact tissue‐implant thin (1 μm) and ultrathin (70–80 nm) sections were analyzed with light and transmission electron microscopy. Results: Peri‐implant marginal tissues displayed moderate inflammatory infiltrates located adjacent to and beneath the junctional epithelium. One patient affected by oral lichen planus displayed an intense lymphocyte/plasma cell‐dominated immune reaction. Deep peri‐implant tissues surrounding mobile implants consisted of a dense, fibrous tissue capsule with minimal inflammation. Epithelial downgrowth was observed around four implants. Small areas of nonmineralized bone in contact with the implant were noticed in the apical portion of two implants. One implant was almost entirely colonized by bacterial plaque with the exception of its apical portion, where bone‐implant contact was observed. The stable implant was characterized by bone‐implant contact. Conclusion: Altogether clinical, radiographic, and histologic findings indicated that two major etiologic factors might have been implicated in the failure process of the investigated implants: excessive occlusal load in relation to the bone‐supporting capacity and, in two cases, infection.     

Clinical parameters associated with success and failure of single-tooth titanium plasma-sprayed cylindric implants under stricter criteria: a 5-year retrospective study

PURPOSE: The purpose of this study was to determine the clinical parameters associated with long-term success and failure of single-tooth titanium plasma-sprayed (TPS) cylindric implants. MATERIALS AND METHODS: Thirty-nine implants in 39 subjects were followed for 5 years. The following data were collected: subject age and gender, implant length, implant location, bone density, and implant position in relation to crestal bone. Assessments made at recall intervals included: Gingival Index (GI), probing depth, relative attachment level, and standardized radiographs. Failure was defined as a mean annual attachment loss rate (ALR) of > or = 0.25 mm after the first year of implant function. Between-group differences were assessed nonparametrically using the Mann-Whitney and chi-square tests. RESULTS: Nineteen implants were considered successes and 20 were considered failures with respective mean ALRs of 0.12 +/- 0.07 mm and 0.42 +/- 0.19 mm. The following factors were associated with success: longer implants (P < .001), lower GI (P < .001), higher bone density (P < .0001), and implant position at the crest or supracrestally (P <.0001). Age, gender, probing depth, and implant location were not related to outcome. CONCLUSIONS: A model using attachment loss as a parameter for success and failure has not been previously utilized. Longer implants, lower GI, higher bone density, and implant position at the crest or supracrestally were clinical factors associated with long-term success of single-tooth TPS cylindric implants in this patient population.     

Implant zones of the jaws: implant location and related success rate

The article demonstrates the factors of importance in the early and late failures of dental implants based on literature review. An implant location is one of many factors that can influence a success or failure of dental implants. The author identifies and describe four alveolar jaw regions--functional implant zones--with unique characteristics of anatomy, blood supply, pattern of bone resorption, bone quality and quantity, need for bone grafting and other supplemental surgical procedures, and a location-related implant success rate. The article discusses predisposing factors that can lead to early implant failures in different jaw zones. An implant location is investigated as one of these factors. A prior history of trauma to premaxillary region is described in the context of implant success in anterior maxilla. This zone is being referred by the author as the "traumatic zone." The challenges of mandibular posterior implant reconstruction are presented in the context of blood supply to the mandible. A deficiency of vascularization in this region, especially in elderly and edentulous patients, lead the author to refer to this zone as the "ischemic zone." The concept of relative ischemia of the posterior mandible that can develop with age and tooth loss is discussed. A thorough understanding of specifics of each functional implant zone should help to improve successes and prevent failures of dental implants.     

Timing of implant placement relative to tooth extraction

Summary  In recent years, immediate or early implant placement after tooth extraction has becoming more common. The present review focuses on the clinical outcome of immediate or early implant placement. Only limited knowledge exists about most of the factors with particular significance for this treatment mode. Randomized controlled clinical studies comparing the various treatment protocols are scarce. With the background in the existing literature some conclusions can be drawn with caution. Survival rates for implants placed immediately, early, delayed, or late seem to be similar in the short perspective and amounts to approximately 95%. Successful immediate implant placement may be possible in all regions of the jaws, although replacement of molars is more challenging. Chronic infection is not an absolute contraindication for immediate implant placement. It is controversial whether immediate placement of implants may preserve the alveolar bone. Small gaps between implant surface and socket wall have a potential for spontaneous healing. No consensus exists on the need for bone augmentation in these situations. With the limited information available it may be stated that a good prognosis can be obtained following immediate/early functional or non-functional loading of immediately placed implants. However, higher risk of failures seems to exist compared with a delayed, conventional approach. It is advocated that this treatment modality should be restricted to skilled well-trained teams. Data on the aesthetic outcomes following immediate/early implant placement are inconclusive, but this treatment can offer high patient satisfaction with the aesthetic and functional outcomes.     

Early implant failures in patients treated with Brånemark System titanium dental implants: a retrospective study

Implant failure has been associated with factors such as poor bone quality, insufficient bone volume, implant instability, unfavorable implant loading, and smoking habits. Infections and host responses may also be important factors in dental implant failure. The objectives of the present study were to identify various explanatory factors associated with titanium implant failure. Forty subjects with stage 1 non-osseointegrated titanium dental implants (NOTI) ad modum Br?nemark and 40 age- and gender-matched control subjects with successfully osseointegrated titanium implants (SOTI) were studied. Clinical data and gamma G immunoglobulin (IgG) antibody titers were studied. An independent t test revealed that significantly longer implants were placed in subjects with SOTI (P < .05). Statistically significant differences in bone shape and resorption (BSR) scores were found between SOTI and NOTI (P < .05). Logistic regression analysis identified 3 significant explanatory outcome variables: serum antibody avidity scores for Bacteroides forsythus (P < .0001), serum antibody titers to Staphylococcus aureus (P < .001), and the BSR scores (P < .05). Antibody avidity to B forsythus and antibody titer to S aureus were therefore the 2 most important factors associated with early implant failures and with a significant predictive ability. This indicates that immunologic factors are involved in osseointegration.     

Failure of oral implants: aetiology, symptoms and influencing factors

The use of oral implants opened a wide range of prosthetic treatment possibilities in edentulous patients. Although the reported success rates of oral implants are high, failures do occur. This paper reviews the current knowledge about the aetiology, the signs and symptoms and the possible influencing factors of implant failure. Possible causes of implant failure are thought to be infection of the periimplant tissues, occlusal overload, or a combination of both. Nevertheless, pinpointing one of these as the aetiological factor in a particular case is difficult and should be handled reluctantly. Although the cause might seem obvious, influencing factors could play a role as well. Gaining insight into these processes might stimulate the adoption of preventive action and therefore increase the predictability of the treatment outcome with oral implants. Received: 4 April 1997 / Accepted: 27 November 1997     

Management of Maxillary Cluster Implant Failures with Extra‐Maxillary Implants: A Clinical Report

Late cluster implant failures can be one of the most devasting outcomes of implant therapy for patients. It can have anatomic, functional, psychological and financial consequences for patients, and sometimes the loss of residual bone can preclude subsequent implant placement. Fortunately, management of cluster implant failures in the maxilla can be mitigated by using implant anchorage from remote sites like zygomatic and pterygoid regions. Few reports exist in the literature that have described the management of cluster implant failure using extra‐maxillary implants such as zygomatic and pterygoid implants. This case report describes the management of a female patient with bruxism who experienced late cluster implant failure in the maxilla after 9 years of function with an overdenture. Due to the loss of residual bone, subsequent implant therapy involved the use of bilateral zygomatic, pterygoid and anterior maxillary implants, which were immediately loaded and thereafter used to support a complete arch fixed implant‐supported zirconia prosthesis.     

Factors affecting late implant bone loss: a retrospective analysis

PURPOSE: Prevention of late implant bone loss is a critical component in long-term success of implants. The aim of the present study was to evaluate factors affecting late implant bone loss. MATERIALS AND METHODS: Three hundred thirty-nine endosseous root-form dental implants placed between April 1981 and April 2002 in 69 patients were analyzed. The implants were categorized based on the following factors: (1) surface characteristics (smooth versus rough), (2) length (short [< 10 mm] versus long [> or = 10 mm]), width (narrow [< 3.75 mm], regular [3.75 to 4.0 mm], or wide [> 4.0 mm]), (3) the amount of keratinized mucosa (< or > or = 2 mm), (4) location (anterior versus posterior; maxilla versus mandible), (5) type of prosthesis (fixed versus removable), and (6) type of opposing dentition. The effects of these factors on clinical parameters, especially average annual bone loss (ABL), were evaluated clinically and radiographically by a blinded examiner. The parameters evaluated were modified Plaque Index, Gingival Index, modified Bleeding Index, probing depth, and ABL. RESULTS: Shorter implants, wider implants, implants supporting fixed prostheses, and implants in smokers were found to be associated with greater ABL (P < .05). The random intercept mixed effects model showed that implant length was the most critical factor for maintenance of ABL. CONCLUSIONS: Shorter implants, wider implants, implants supporting fixed prostheses, and implants in smokers were associated with greater ABL. Implant length was the most significant factor in the maintenance of dental implants. Randomized controlled clinical trials are needed to confirm the results obtained from this retrospective clinical study.     

Immediate implant placement in molar regions: risk factors for early failure

Objectives: To identify risk factors for early failure of immediately placed implants in molar regions associated with three bone regenerative techniques. Methods: Ninety‐two patients (44 women and 48 men; mean age 50 years, 35 smokers and 57 non‐smokers) in need of a single implant crown to replace a molar were included. After placing the implant, patients were randomized to one of three treatment groups for bone reconstruction of remaining periimplant defects: Autologous bone (AB) chips, Ossix membrane (OM) or a combination of AB chips and OM. The implant was submerged, and after 4 months of healing a re‐entry surgery was made to connect a healing abutment. Implants with a dehiscence on ≥2 sites (mesial/distal/oral/buccal) together with≥50% visible threads, were judged as failures. A series of simple logistic regression analyses were performed to identify risk factors for failure among the following independent variables: sex, jaw, smoking status, plaque, bleeding on probing, fistula, extraction reason, mean initial periimplant defect size, treatment group, implant length, buccal bone dehiscence (BBD), soft‐tissue dehiscence and infection. The identified risk factors entered a multiple logistic regression analysis. Results: Fifteen implants failed before abutment operation (13 explantations/two non‐osseointegrated). Treatment group had no impact on failure. Risk factors for failure were: Smoking >10 cigarettes/day (odds ratio [OR]=9.29, confidence interval [CI]=1.21–71.16), BBD (OR=11.43, CI=1.34–97.74) and infection (OR=36.7, CI=2.75–489.31). Conclusions: Implants placed immediately after extraction of a molar were associated with a high risk for failure at abutment operation. There was no difference in failure rate between three bone reconstructive techniques. To cite this article:
Urban T, Kostopoulos L, Wenzel A. Immediate implant placement in molar regions: risk factors for early failure.
Clin. Oral Impl. Res. 23 , 2012; 220–227.
doi: 10.1111/j.1600‐0501.2011.02167.x