Comparison of implant survival with implants placed in acceptable and compromised bone: a literature review

Background  Survival rates for conventional dental implant systems are relatively high in normal healthy bone. However, there are subgroups of patients that are at an increased risk of implant failure. In particular, patients with compromised quantity or quality of bone present a significant challenge to the dental implantologist. Objective  To perform a review of the literature in an attempt to quantify the relative risk of implant failure in compromised bone compared to good or acceptable bone and to identify whether certain anatomical regions are at greater risk. Search Strategy  We conducted a systematic electronic database search of Medline, Cinhahl and the Cochrane Library through March 2006 identifying articles meeting the eligibility criteria. Results  We calculated an increased risk of implant failure in compromised bone compared to healthy bone in both the maxilla and the mandible using conventional dental implant systems. Relative risks ranged from 2 to 12 with the highest risk of failure in the maxilla. Conventional systems are often used in combination or after bone augmentation procedures or more innovative methods for stimulating bone growth in patients with compromised bone. These approaches do have their limitations including high costs, the accumulation of the surgical risks, and delayed time to loading. Discussion  Quantifying the risk of implant failure in patients with compromised bone should assist the implantologist in treatment decision making and patient counseling. Alternative methods for treating patients with compromised bone include zygomatic and lateral implants, neither of which typically require bone augmentation procedures. More studies are needed to evaluate their safety and efficacy.     

Immediate loading of mandibular implants in compromised patients: preliminary results

To minimize the number of implant surgical procedures, a total of 72 single-stage, transgingival Frialoc implants (Friadent) were placed in the mandibles of 18 patients who required implant restoration. The patients' ability to undergo surgical implant treatment was restricted because of either poor general medical health or psychologic conditions. All implants were immediately loaded with a bar-retained overdenture. Only 4 of the 72 immediately loaded Frialoc implants (in one patient) failed over a control period of 29 months. The cumulative implant survival rate was 94.4%. Apart from an initial increase in bone resorption at two posterior implants supporting a cantilever bar (the cantilevers were removed 13 months after delivery of the prosthesis) and serious lip swelling in one patient, there were no further serious surgical, prosthetic, or general medical problems during the treatment period. The initial results of the study indicate that the single-stage Frialoc System allows fast prosthetic mandibular restorations. Because there is only one operation, the risk of local or general health complications in compromised patients is reduced.     

Outcomes of dental implants placed in a surgical training programme

Background: This study evaluates surgical outcomes and survival rates of implants placed in a multidisciplinary implant teaching programme. Methods: A retrospective review of all implant surgery performed over a 6‐year period by accredited oral and maxillofacial surgery trainees at the Royal Dental Hospital of Melbourne was undertaken. Patients were reviewed for a minimum of 6 months post‐implant placement. Implant survival was defined as those implants which were not removed, were clinically integrated as assessed by torque testing and in an appropriate position to receive a subsequent prosthesis. Kaplan‐Meier analysis was used to assess overall survival and univariate factors affecting survival. Multivariate analysis used Cox proportional hazards models. Results: Over 6 years, 127 patients were treated. Follow‐up data were present for 105 patients with 236 implants placed. Survival of implants at 1 and 5 years was 94 per cent and 92.8 per cent, respectively. The only univariate and multivariate factor which affected implant survival was perioperative bone grafting. All failed implants were single stage. Other factors such as patient age, smoking status, implant site, anaesthetic type, immediate or delayed placement, implant length and diameter, and medical comorbidities did not significantly affect implant survival. Conclusions: A satisfactory implant survival rate was found in a tertiary teaching centre. Perioperative bone grafting significantly increased the risk of implant failure.     

Dental implants retrieved from humans: a diagnostic light microscopic review of the findings in seven cases of failure.

With the increased use of dental implant systems, an increase in the number of implants removed from patients has also been observed. This investigation attempted to elucidate some underlying causal determinants of implant failure employing light microscopic analyses. Valuable data can be obtained from implants retrieved from patients. Implant success is predicted on proper patient selection and treatment planning, careful surgical procedures, careful prosthodontic management, and continued oral hygiene maintenance.     

Hydroxyapatite coatings in implant dentistry.

Hydroxyapatite coatings have shown promise due to the enhanced integration of osseous tissues to coated implant surfaces. When compared with healing around commercially pure or titanium alloy implant surfaces, hydroxyapatite-coated implants appear to be superior in sites which are compromised in either quantity or quality of bone. In spite of these encouraging findings, the long-term stability of the hydroxyapatite/bone interface has been challenged. Microbiologically, the hydroxyapatite-coated implant surface may be at an increased risk to bacterial plaque. However, after 8 years of clinical utilization, the hydroxyapatite-coated implant surface has not been shown to be predisposed to increased long-term failure. Available research as it pertains to this controversial area of implant dentistry is reviewed.     

Maxillary sinus augmentation as a risk factor for implant failure

PURPOSE: The investigators sought to determine whether maxillary sinus augmentation (MSA) was an independent risk factor for implant failure. MATERIALS AND METHODS: Using a retrospective cohort study design, the investigators enrolled a sample composed of subjects having 1 or more implants placed in the posterior maxilla. The primary predictor variable was MSA status at the time of implant placement (MSA present or absent). MSA consisted of a lateral window (external) or an osteotome (internal) procedure. The outcome variable was implant failure defined as implant removal. Demographic, health status, anatomic, implant-specific, abutment-specific, prosthetic, and perioperative variables were also examined. Overall implant survival was estimated using Kaplan-Meier analysis. Risk factors for implant failure were identified using Cox proportional hazard regression models. RESULTS: The sample consisted of 318 patients and 762 posterior maxillary implants. The mean duration of follow-up was 22.50 +/- 19.06 months. The 5-year survival rates for implants in the ungrafted and grafted posterior maxilla were 88.0% and 87.9%, respectively (P = .08). After adjustment for covariates, MSA status was not an independent risk factor for implant failure (P = .9). Tobacco use (P < .001), implants replacing molars (P < .001), and 1-stage implants (P < .001) were statistically associated with an increased risk for implant failure. DISCUSSION: MSA status was not associated with implant failure risk. This finding may be subject to selection bias, as successful MSA was requisite prior to implant placement. CONCLUSION: MSA status was not associated with an increased risk for implant failure. Of the 3 factors associated with an increased risk for failure, tobacco use and implant staging may be modified by the clinician to enhance outcome.     

Multicenter retrospective analysis of 201 consecutively placed camlog dental implants

Camlog tube-in-tube implants were introduced several years ago. This multicenter retrospective analysis evaluated the success rate of Root-Line and Screw-Line tube-in-tube implants in daily use. A total of 201 implants were placed in 96 patients with different indications and implantation procedures. Implants were analyzed retrospectively after a functional loading period of 12 to 78 months. At the end of the observation period, all but 1 implant fulfilled the success criteria, resulting in an implant survival rate of 99.5%. Individual case analysis of implants in special indications, such as immediate loading, short implants, and tilted implants, did not indicate any increased risk of implant failure.     

The medically compromised patient: Are dental implants a feasible option?

In healthy subjects, dental implants have evolved to be a common therapy to solve problems related to stability and retention of dentures as well as to replace failing teeth. Although dental implants are applied in medically compromised patients, it is often not well known whether this therapy is also feasible in these patients, whether the risk of implant failure and developing peri‐implantitis is increased, and what specific preventive measures, if any, have to be taken when applying dental implants in these patients. Generally speaking, as was the conclusion by the leading review of Diz, Scully, and Sanz on placement of dental implants in medically compromised patients (J Dent, 41, 2013, 195), in a few disorders implant survival may be lower, and the risk of a compromised peri‐implant health and its related complications be greater, but the degree of systemic disease control outweighs the nature of the disorder rather than the risk accompanying dental implant treatment. So, as dental implant treatment is accompanied by significant functional benefits and improved oral health‐related quality of life, dental implant therapy is a feasible treatment in almost any medically compromised patient when the required preventive measures are taken and follow‐up care is at a high level.     

Dental implants in the medically compromised patient

Objective

It has been suggested that some local and systemic factors could be contraindications to dental implant treatment. The objective of this paper was to evaluate whether success and survival rates of dental implants are reduced in the medically compromised patient.

Data/sources

An extensive literature search was conducted using PubMed/Medline, Scopus, Scirus and Cochrane databases up to November 8, 2012.

Conclusions

There are very few absolute medical contraindications to dental implant treatment, although a number of conditions may increase the risk of treatment failure or complications. The degree of systemic disease-control may be far more important that the nature of the disorder itself, and individualized medical control should be established prior to implant therapy, since in many of these patients the quality of life and functional benefits from dental implants may outweigh any risks.     

Combined periodontal and implant treatment of a case of aggressive periodontitis

Aggressive periodontitis renders a great challenge to clinicians with regards to treatment and prosthodontic rehabilitation. A compromised remaining dentition and a tendency toward refractory disease make it difficult to establish a treatment plan that renders an adequate long-term prognosis. Although the use of implants has become a common treatment modality, limited data are available on the use of dental implants in patients with aggressive periodontitis, especially for cases necessitating the use grafting procedures preceding implant placement. In this case report the successful treatment of a patient with aggressive periodontitis by the combined use of periodontal and implant treatment necessitating preceding augmentive procedures is described.     

Dental implant treatment in a severely compromised (irradiated) patient.

When faced with a patient with relative medical or psychological contra-indications, the practitioner may be tempted to withhold dental implant treatment because of the risks. Yet, for some highly motivated but compromised patients, the potential benefits of implant treatment can be an overriding consideration. In the case presented here, a 56-year-old patient who had undergone two series of radiation therapy and surgery for recurring cancer of the tongue was treated first with a subperiosteal, and, when the subperiosteal was removed after six years, the patient was treated with endosseous implants. This treatment significantly improved the patient's life without further negative effect on her medical condition.     

Time dependent failure rate and marginal bone loss of implant supported prostheses: a 15-year follow-up study

This study deals with 4971 implants (Brånemark system) installed in 1315 patients, either fully or partially edentulous, and followed from implant installation up to the last control. A predominance of female patients (61%) and a nearly equal number of upper and lower jaws characterised the study group. Patients were scheduled each 6–12 months for recall. The observation time varied from 0.5 to 15 years (mean 5.1). The whole cohort was split up into compromised (n=59) and non-compromised (n=1256) patients. The former are defined as grafted (autologous bone) and patients irradiated in the head and neck area. In the compromised patients 24 out of 59 patients (40.6%) showed failures, in whom 59 out of 310 (19%) implants failed. In the non-compromised patients, implant failures were observed in 11.6% of the patients, which corresponds to 5.9% of the installed implants, excluding iatrogenic failures. Failures were further divided chronologically into early (up to 1 year after abutment connection) and late failures. There were early implant failures in 12.5% of the compromised patients and in 3.4% of the others. Late implant failures occurred in 7.4 and 2% of the two patients groups, respectively. While gender did not affect the failure rate, implant lengths, corresponding to the available bone height did, since a 21.5% failure rate for the 7-mm implants contrasts with 4.1 and 3.8% for 13- and 15-mm implants, respectively. Early as well as annual late failures are more frequently found in the maxilla. Implant fractures only occurred in the fixed (both partial and full) prosthesis group but never surpassed the 0.2% annual level. Marginal bone loss, exceeding the third screw thread occurred in 1.8% of the implants at the last control. It appears that this type of implant configuration offers a high long-term predictability. Failures occur before, at or during the first year after abutment connection and in very short implants. Marginal bone as a whole is very stable over the years.     

A comparison of characteristics of implant failure and survival in periodontally compromised and periodontally healthy patients: a clinical report

PURPOSE: This study compares implant survival and patterns of implant failure in periodontally compromised and periodontally healthy patients. MATERIALS AND METHODS: In a private periodontal practice, over a 13-year period, implants were placed in both periodontally compromised and periodontally healthy patients. Implants were classified in 5 different groups according to surface texture. Survival rates in each group were compared according to implant location, diameter, length, and phase of treatment. RESULTS: A total of 1,511 implants were placed in 334 patients. One hundred fifty-one of these patients, classified as periodontally compromised patients (PCP), received 923 implants. The remaining 183 patients, classified as periodontally healthy patients (PHP), received 588 implants. The overall survival rate for implants placed in the PHP group was 93.7%, compared to 90.6% in the PCP group. The survival rate of hydroxyapatite-coated implants was 92.6% in the PHP group and 81% in the PCP group. The survival rate of the turned-surface implants was similar in both groups. DISCUSSION: Two types of implant failure were identified. The first was failure of the implant to osseointegrate. This type of failure occurred early in treatment and appeared to be related to smooth-surface implants placed in bone of low density. Failures of this type were distributed equally between the PHP and PCP groups. The second type of failure was related to peri-implantitis. It was observed most often with implants with hydroxyapatite surfaces, occurred as the result of a progressive condition, and was most prevalent in the PCP group. CONCLUSION: Further long-term controlled investigations are needed to determine the influences of implant suface and host susceptibility on implant failure in both PHP and PCP.     

Immediate dental implant placement in post-extraction-infected sites decontaminated with Er,Cr:YSGG laser: a retrospective cohort study

Dental implants placed in fresh extraction alveoli provide several advantages, including shorter treatment periods and improved patient comfort. After a compromised tooth extraction, the Er,Cr:YSGG laser can considerably reduce bacterial concentration. The objective of this controlled study conducted after at least 1 year of follow-up was to compare the use of immediate post-extraction implants in infected sites treated with laser (test group) versus conventional implants in edentulous sites (control group) through an analysis of pre- and post-operative radiographs. The study was based on a series of patients treated between 2014 and 2019, with a 1-year minimum follow-up, and up to over 4 years. An analysis of the clinical history of the treated patients and pre- and post-operative radiographs was performed to evaluate the implant success and to measure the marginal bone level (MBL). Overall, 149 implants were studied. There was only one failure in the test group (1%) and no failures in the control group. The test group gained 0.1 mm of the MBL compared to the baseline, while the control group lost 0.1 mm of the MBL. The difference between the two groups of only 0.2 mm was not statistically significant (P = 0.058). Immediate dental implants in infected sockets debrided and decontaminated using Er,Cr:YSGG laser do not appear to enhance the likelihood of failure; however, peri-implantitis and associated problems must be avoided by following a certain set of protocols and procedures.

     

Hydrophilic implants generated using a low-cost dielectric barrier discharge plasma device at the time of placement exhibit increased osseointegration in an animal pre-clinical study: An effect that is sex-dependent

ObjectivesIncreased wettability of titanium and titanium alloy surfaces due to processing and storage methods increases osteoprogenitor cell differentiation and osseointegration compared to microroughness alone. Implants that are exposed to air have a hydrophobic surface due to adsorption of atmospheric hydrocarbons, which can limit overall implant success. Dielectric barrier discharge plasma (DBD) is one method to increase surface hydrophilicity. Although current DBD methods yield a hydrophilic surface, adsorbed hydrocarbons rapidly restore hydrophobicity. We demonstrated that application of DBD to implants previously packaged in a vacuum, generates a hydrophilic surface that supports osteoblastic differentiation in vitro and this can be done immediately prior to use. In the present study, we tested the hypothesis that DBD treatment to alter surface wettability at the time of implant placement will improve osseointegration in vivo.Materials and methodsTwenty male and sixteen female rabbits were used in a preclinical trans-axial femur model of osseointegration. Control and DBD treatment implants were inserted randomized per hind limb in each rabbit (1 implant/hind-limb). At 6 weeks post-surgery, bone-to-implant contact, adjacent bone volume, and torque to failure were assessed by micro-CT, calcified histology, and mechanical testing.ResultsDBD plasma treatment of vacuum-sealed implants increased surface wettability and did not change surface chemistry or roughness. Peak torque and torsional energy, and bone-to-implant contact increased with DBD treatment in males. In contrast, female rabbits showed increased osseointegration equal to DBD treated male implants regardless of DBD plasma treatment.ConclusionDBD treatment is an effective method to enhance osseointegration by increasing surface wettability; however, this response is sex dependent. In healthy female patients, DBD treatment may not be necessary but in older patients or patients with compromised bone, this treatment could be an effective measure to ensure implant success.     

Titanium endosteal dental implants in the mandibles of beagle dogs: a 2 year study.

Forty of 44 vented endosteal blade implants were well tolerated by the mandibular tissues of beagle dogs, as demonstrated clinically, radiographically, and histologically. Infection and inflammation were not observed. The epithelium did not invade along the neck of the implants more than 2 mm. below the mandibular crest. After 3 to 6 months, except for increasing density of bone at the metal interface, no distinct pattern of reaction could be discerned histologically. Except for heavy collagenous investment in three dogs, there was no sign of the implants being treated as sterile foreign bodies. In this study, histology did not provide good criteria for evaluating the failure of vented endosteal blade implants. In four implants which failed, the most reliable signs of failure were increased mobility and/or sulcus depth around the neck of the abutments. Radiographic evaluation of implants provided the best means of determining bone resorption. Bone resorption was apparent 3 to 6 months after implantation, did not appear to be progressive, and did not indicate implant failure or impending implant failure in those animals in which it occurred. Radiolucent areas observed in 29 of the specimens contained connective tissue, marrow spaces, thin bone trabeculae, and nonpathologic tissues. Although in some of the dogs stress on implants did not cause failure, there is a need for further experimentation involving vented endosteal blades subjected to occlusal loading.     

Non-grafted sinus implants in periodontally compromised patients: a time-to-event analysis

This study reports the results of implant therapy involving a sinus membrane lift and of conventional implant therapy in 68 periodontally compromised patients treated between June 1990 and June 2002. Patients had at least two implants inserted, one of which was placed in the maxillary sinus region following fenestration of the lateral sinus wall and lifting of the sinus membrane. Two implant systems were used: a two-stage system (Astra) and a one-stage system (ITI). Annual follow-up visits included recording of plaque, probing pocket depth and measurement of the radiographic distance in millimeter from the implant shoulder to the alveolar crest. Survival analysis showed that the proportion of implants that had not been explanted after 5 years ranged between 88.7% for ITI sinus implants and 97% for ASTRA conventional implants. After 10 years, the proportion of implants remaining in situ ranged between 59% for ITI conventional implants and 97% for ASTRA conventional implants. Cox regression analyses showed that the factors influential for implant explantation were implant type (HR(ITI) = 2.8), implant length (HR(< or = 10 mm) = 3.1), patient being a smoker (HR(smoking) = 2.2) and patient having at least 20 natural teeth (HR(> or = 20 teeth) = 3.8). Our results demonstrate that sinus implants may be inserted with the same success as conventional implants in periodontally compromised patients.     

Solutions for Severely Angulated Implants in the Mandibular Overdenture: A Clinical Report

Results of randomized clinical trials have confirmed that implant overdentures provide patients with better outcomes than do conventional complete dentures. Several designs have been introduced for the mandibular implant-retained removable prosthesis. The most commonly used prosthesis design for the mandibular overdenture is two implants in the canine areas with a stud attachment mechanism (i.e., ball attachments). This design is the least expensive, and therefore can service more patients and is now considered to be the "Standard of Care" for the mandibular edentulous patient. Proper treatment planning and execution lead to favorable implant placement and a successful prosthetic restoration and ultimately patient satisfaction; however, implant malposition may occur, which can lead to an unsuccessful prosthesis. This clinical report describes an implant overdenture design used for severely angled implants. Prosthodontic techniques that enabled this patient to have a successful outcome included the use of cast-to attachments and abutments along with a sectional matrix used to locate these components within the bulk of the prosthesis. For this patient the prosthodontic compromises were preferred over another surgical procedure with the additional time, discomfort, increased cost, and possible surgical morbidity. It is important that the patient understand the compromises and potential problems when implant placement is not ideal, especially the potential for implant overload and failure.     

Risk factors for endosseous dental implant failure

Failures of endosseous dental implants are rare and tend to cluster in patients with common profiles or risk factors. Clinical trials indicate that factors related to implant devices, anatomy, occlusion,systemic health or exposures, microbial biofilm, host immuno-inflammatory responses, and genetics may increase the risk for im-plant complications or loss. In general, factors associated with the patient appear more critical in determining risk for implant failure than those associated with the implant itself. Several risk factors can be modified. For example, the patient can modify smoking and the clinician can modify implant selection, site preparation,and loading strategy. In identifying these factors and making appropriate interventions, clinicians can enhance success rates while improving oral function, esthetics, and patient well-being.