Implant failure predictors in the posterior maxilla: a retrospective study of 273 consecutive implants

Survival analysis of implants placed simultaneously with lateral sinus floor elevation in severely atrophic maxilla: A 3- to 12-year retrospective cohort study

OBJECTIVES

To retrospectively evaluate whether implants placed simultaneously with lateral sinus floor elevation (LSFE) in severely atrophic maxilla (residual bone height [RBH] ≤3 mm) could achieve long-term survival and comprehensively analyze the factors influencing their survival rates.

MATERIALS AND METHODS

A total of 123 patients receiving LSFE and simultaneous implant placement from 2010 to 2019 and their 123 implants in sites with RBH ≤3 mm were included in this study. Basic characteristics of patients and implants were collected from the medical record system and cone-beam computed tomography (CBCT) images. Kaplan-Meier survival curves were applied to estimate cumulative survival rates (CSRs) and Cox proportional hazards regression models were used to detect factors influencing implant survival.

RESULTS

The 6-year and 12-year CSR of implants placed in sites with RBH ≤3 mm were 95.7% (95% confidence interval [CI]: 92.1%-99.5%) and 76.6% (95% CI: 58.1%-100%), respectively. Eight patients presented late implant failure. Univariate and multivariate Cox regression analyses demonstrated that RBH ≤2 mm (hazard ratio [HR]: 20.63, p = 0.000) and smoking habit (HR: 6.055, p = 0.024) were significantly associated with long-term implant survival. Specifically, the 10-year CSR of implants in sites with RBH ≤2 mm (53.3%, 95% CI: 27.5%-100%) was dramatically lower than those in sites with RBH >2 mm (92.9%, 95% CI: 81.7%-100%, p = 0.000).

CONCLUSIONS

Implants placed simultaneously with LSFE in sites with RBH ≤3 mm can achieve long-term survival. However, caution is required especially for implantation in sites with RBH ≤2 mm. Besides, the smoking habit is also considered a risk factor jeopardizing long-term implant survival.

Implant site development requirements in an advanced dental education program: A series of 290 implants

PURPOSE

Our purpose was to assess the frequency and impact of various site development procedures provided before, during, and after implant placement in an advanced dental education program.

METHODS

We evaluated all implant cases completed by two residents in each of three consecutive periodontics residency classes. Dependent variables included implant failure, complication occurrence, presence of radiographic bone loss, and need for tissue augmentation. We analyzed these outcomes against a panel of explanatory covariates.

RESULTS

Our study sample involved 370 site development procedures at 290 implant sites in 160 patients. Three factors exhibited statistically significant associations with need for tissue augmentation: alveolar ridge preservation (ARP) (odds ratio [OR] 0.28; 95% confidence interval [CI] 0.13, 0.57), immediate implant placement (IIP) (OR 0.21; 95% CI 0.10, 0.47), and implant submergence (OR 8.3; 95% CI 4.5, 15.3). Four factors predicted treatment complications: ARP (OR 6.1; 95% CI 1.3, 29.1), IIP (OR 6.1; 95% CI 1.06, 35.3), implant submergence (OR 5.3; 95% CI 1.1, 24.9), and mandibular arch (OR 31.3; 95% CI 1.9, 500). Anterior sites (OR 2.7; 95% CI 1.3, 5.8) were more likely to receive IIP.

CONCLUSIONS

In the evaluated sample, implant placement at a site exhibiting a favorable volume of native bone was rare. Seventy-eight percent of sites received hard tissue grafting during the treatment phase. The use of ARP or IIP at tooth extraction reduced subsequent tissue augmentation requirements. Education and training in ARP and other site development procedures may enhance the clinical practice and treatment outcomes of implant surgeons.

Effects of Magnetic Stimulation on Dental Implant Osseointegration: A Scoping Review

This PRISMA-ScR driven scoping review aims to evaluate the influence of magnetic field stimulation on dental implant osseointegration. Seven databases were screened adopting ad-hoc strings. All clinical and preclinical studies analyzing the effects of magnetic fields on dental implant osseointegration were included. From 3124 initial items, on the basis of the eligibility criteria, 33 articles, regarding both Pulsed ElectroMagnetic Fields (PEMF) and Static magnetic Fields from permanent Magnets (SFM) were finally included and critically analyzed. In vitro studies showed a positive effect of PEMF, but contrasting effects of SFM on bone cell proliferation, whereas cell adhesion and osteogenic differentiation were induced by both types of stimulation. In vivo studies showed an increased bone-to-implant contact rate in different animal models and clinical studies revealed positive effects on implant stability, under magnetic stimulation. In conclusion, although positive effects of magnetic exposure on osteogenesis activity and osseointegration emerged, this scoping review highlighted the need for further preclinical and clinical studies. More standardized designs, accurate choice of stimulation parameters, adequate methods of evaluation of the outcomes, greater sample size and longer follow-ups are needed to clearly assess the effect of magnetic fields on dental implant osseointegration.

Etiology, occurrence, and consequences of implant loss

Implant therapy aims at providing the patient with a functional and esthetically pleasing rehabilitation in a long‐term perspective. The loss of an implant constitutes a major complication, which may have an impact on the treatment plan and/or jeopardize the longevity of the restoration. Implant loss may occur during the phase of osseointegration (early) or at a later time when the previously achieved osseointegration is lost (late). The present work evaluates the evidence on the occurrence of both events and discusses etiology, risk factors, and consequences.

Long-Term Comparison of Survival and Marginal Bone of Implants with and without Sinus Augmentation in Maxillary Molars within the Same Patients: A 5.8- to 22-Year Retrospective Study

Maxillary sinus floor augmentation (MSFA) is widely used and considered a predictable procedure for implant placement. However, the influence of MSFA on implant survival and marginal bone loss (MBL) is still inconclusive. The purpose of this retrospective observational study is to evaluate the long-term genuine influence of MSFA on the survival and MBL of implants by comparing those with and without MSFA only in maxillary molars within the same patients. Thirty-eight patients (28 male and 10 female), with a total of 119 implants, received implants with and without MSFA, and were followed up for 5.8 to 22 years. Patient- and implant-related factors were assessed with a frailty model for implant survival and with generalized estimation equations (GEE) for MBL around the implant. No variables showed a statistical significance for implant failure in the frailty model. In GEE analysis for MBL, MSFA did not show any statistical significance. In conclusion, MSFA demonstrated no significant influence on implant failure and MBL in posterior maxilla in this study.

The risk factors of early implant failure: A retrospective study of 6113 implants

BACKGROUND

The risk factors of early implant failure were controversial among previous studies, especially for implants in different sites.

PURPOSE

To analyze the rate and risk factors of early implant failure occurring before the placement of final prosthesis.

MATERIALS AND METHODS

A retrospective study was conducted based on electrical medical records of patients who received dental implant placement from 2015 to 2019. Generalized estimation equation analyses were used to explore potential risk factors influencing early implant failure.

RESULTS

Overall, 6113 implants in 3785 patients were included. The rate of early implant failure was 1.6% at patient level and 1.2% at implant level. The early implant failure was significantly associated with implants in the posterior maxilla, with specific surface modifications and in previously augmented sites (p < 0.05). Risk factors for maxillary implants included surface modification and bone augmentation procedures (p < 0.01), whereas risk factors for mandibular implants included gender and bone augmentation procedures (p < 0.05). For implants placed in previously augmented sites, implants placed in the anterior mandible had a higher risk of early failure (p < 0.05).

CONCLUSIONS

The risk factors for early implant failures varied among different sites; hence, they should be comprehensively considered in presurgical treatment plan.

Evaluation of the Association of Early Implant Failure With Local, Environmental, and Systemic Factors: A Retrospective Study

PURPOSE

This study aimed to assess the association of early implant failure (EIF) with demographic, local, environmental, and systemic factors.

METHODS

Clinical charts of 594 individuals with 2,537 dental implants were assessed. EIF was characterized by implant loss before and up to the abutment connection. Logistic regression analysis was used to verify the association between EIF and local, environmental, and systemic factors at the individual and implant levels. The chosen level of significance was 5%.

RESULTS

EIF occurred in 144 implants (5.68%) and in 97 individuals (16.3%). At the individual level, smoking habits (odds ratio [OR] = 2.54; 95% confidence interval [CI] = 1.00 to 6.47; P = .05), absence of postoperative antibiotic therapy (OR = 2.73; CI = 1.22 to 6.13; P = .02), and bone augmentation (OR = 1.83; CI = 1.17 to 2.85; P = .01) were significantly associated with EIF. At the implant level, smoking habits (OR = 2.90; CI = 1.60 to 5.26, P < .001), absence of postoperative antibiotic therapy (OR = 2.77; CI = 1.36 to 5.63, P = .005), postoperative complications (OR = 28.35; CI = 6.79 to 118.45, P < .001), implant length ≤8.5 mm (OR = 1.79; CI = 1.07 to 2.99; P = .03), and diameter <3.75 mm (OR = 1.65; CI = 1.08 to 2.52, P = .02) were associated with EIF. Age, sex, alcohol abuse, diabetes, hypertension, and long-term medication use were not associated with EIF at both individual and implant levels (P ≥ .12).

CONCLUSIONS

Smoking habits, absence of antibiotic therapy, bone augmentation, postoperative complications, implant diameter <3.75 mm, and implant length ≤8.5 mm were associated with EIF. Clinicians should be aware of these associations that should be controlled for when feasible. Future cohort studies are required to confirm the risk factors.

The impact of the alveolar bone sites on early implant failure: a systematic review with meta-analysis

Dental implants are the first option for replacement of missing teeth. Failure usually involves additional cost and procedures. As a result, the physician should limit the risk factors associated with implant failures. Implant site is one of many factors that can influence the success or failure of dental implants. The association between early implant failure (EIF) and implant site has yet to be documented. This review aims to estimate the impact of insertion site on the percentage of EIFs. An electronic and manual search of studies that reported early failure of dental implants based on collection site. A total of 21 studies were included in the review and examined for the association between EIF and alveolar site. Subgroup analysis, including a comparison between implants inserted in four alveolar ridge regions of both jaws was performed. The early failure rate was higher for maxillary implants (3.14%) compared to mandibular implants (1.96%). Applying a random effect, risk ratio (RR), and confidence interval (CI) of 95% revealed higher failure in the maxilla compared to the mandible (RR 1.41; 95% CI [1.19, 1.67]; P<0.0001; I²=58%). The anterior maxilla is more critical for early implant loss than other alveolar bone sites. Implants in the anterior mandible exhibited the best success rate compared of the sites.

Do Dietary Supplements and Nutraceuticals Have Effects on Dental Implant Osseointegration? A Scoping Review

Several factors affect dental implant osseointegration, including surgical issues, bone quality and quantity, and host-related factors, such as patients' nutritional status. Many micronutrients might play a key role in dental implant osseointegration by influencing some alveolar bone parameters, such as healing of the alveolus after tooth extraction. This scoping review aims to summarize the role of dietary supplements in optimizing osseointegration after implant insertion surgery. A technical expert panel (TEP) of 11 medical specialists with expertise in oral surgery, bone metabolism, nutrition, and orthopedic surgery performed the review following the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) model. The TEP identified micronutrients from the "European Union (EU) Register of nutrition and health claims made on foods" that have a relationship with bone and tooth health, and planned a PubMed search, selecting micronutrients previously identified as MeSH (Medical Subject Headings) terms and adding to each of them the words "dental implants" and "osseointegration". The TEP identified 19 studies concerning vitamin D, magnesium, resveratrol, vitamin C, a mixture of calcium, magnesium, zinc, and vitamin D, and synthetic bone mineral. However, several micronutrients are non-authorized by the "EU Register on nutrition and health claims" for improving bone and/or tooth health. Our scoping review suggests a limited role of nutraceuticals in promoting osseointegration of dental implants, although, in some cases, such as for vitamin D deficiency, there is a clear link among their deficit, reduced osseointegration, and early implant failure, thus requiring an adequate supplementation.

Bone regeneration in diabetic patients. A systematic review

Background

Oral bone regeneration techniques (OBRT) attempt to provide the appropriate bone volume and density to correctly accomplish dental implant treatments. The objective was to determine whether differences exist in the clinical outcomes of these techniques between diabetic and non-diabetic patients, considering the level of scientific evidence.

Material and Methods

A systematic review following PRISMA statements was conducted in the PubMed, Scopus and Cochrane databases with the search terms: “Diabetes Mellitus”, “guided bone regeneration”, “bone regeneration”, “alveolar ridge augmentation”, “ridge augmentation”, bone graft*, “sinus floor augmentation”, “sinus floor elevation”, “sinus lift”, implant*. Articles were limited to those published less than 10 years ago and in English. Inclusion criteria were: human studies of all bone regeneration techniques, including at least 10 patients and the using OBRT in diabetic and non-diabetic patients. Non-human studies were excluded. They were stratified according to their level of scientific evidence related to SORT criteria (Strength of Recommendation Taxonomy).

Results

The initial search provided 131 articles, after reading the abstracts a total of 33 relevant articles were selected to read the full text and analyzed to decide eligibility. Finally, seven of them accomplished the inclusion criteria: two controlled clinical trials, one cohort study and four case series.

Conclusions

A low grade of evidence regarding the use of OBRT in diabetic patients was found. The recommendation for this intervention in diabetic patients is considered type C due to the high heterogeneity of the type of diabetic patients included and the variability of the techniques applied.

Key words:Diabetes Mellitus, guided bone regeneration, bone regeneration.

Survival of dental implants at sites after implant failure: A systematic review

STATEMENT OF PROBLEM

Despite an overall high survival rate for dental implants, the effectiveness of implant retreatment remains unclear.

PURPOSE

The purpose of this systematic review was to examine the survival rate of implants placed at sites which had an implant failure and to investigate factors that might affect outcomes after retreatment.

MATERIAL AND METHODS

A search of electronic databases limited to English language articles was conducted using the following MeSH terms: "dental implants," "dental implantation," or "dental restoration failure," combined with "retreatment," "replacement," or "reoperation." A hand search of selected journals was also performed. Of the retrieved 668 publications, 8 retrospective clinical studies met the inclusion criteria, providing the survival outcome for 673 implants in 557 patients after retreatment. Implant- and patient-related characteristics related to implant failures were assessed.

RESULTS

The weighted mean survival rate for implants after retreatment was 86.3%, with follow-up ranging from less than 1 year to over 5 years. The survival rates of smooth-surfaced and rough-surfaced implants were compared in 217 retreated implants, revealing a significantly higher survival rate for rough-surfaced implants than for smooth-surfaced implants (90% versus 68.7%). Insufficient data were available to evaluate the effect of patient- or treatment-related characteristics on the survival of implants after retreatment.

CONCLUSIONS

The survival rate of retreated implants is lower than that generally reported after initial implant placement. Higher survival rates were reported with rough-surfaced implants than with smooth-surfaced implants in retreatment. An overall implant survival rate of 86.3% after retreatment suggests that most initial implant failures are likely attributable to modifiable risk factors, such as implant architecture, anatomic site, infection, and occlusal overload.

Simultaneous and delayed direct sinus lift versus conventional implants: Retrospective study with 5-years minimum follow-up

Background

To compare the radiological parameters and success of posterior maxillary direct sinus lift with simultaneous or delayed implant placement, or implant placement in native bone, after a minimum follow-up period of 5 years.

Material and Methods

A retrospective cohort study was carried out in a university clinic, selecting patients subjected to implant treatment in the posterior maxilla between the years 2005 and 2011. The patients were divided into three groups: 1) implants placed in native bone; 2) direct sinus lift with simultaneous implant placement; and 3) direct sinus lift with delayed implant placement. Bone crest level, bone loss, vertical bone gain, and implant success and survival after a minimum follow-up period of 5 years after prosthetic loading were analyzed.

Results

A total of 163 patients and 329 implants were included in the study. The mean duration of follow-up was 7.0 ± 1.9 years. Bone loss and implant success and survival were very similar in all three groups, with no significant differences among them. Graft reabsorption was greatest during the first 12 months, though graft stabilization was confirmed after 5 years of follow-up.

Conclusions

Bone loss and percentage success and survival proved very similar for the implants placed in native bone and for sinus lift with simultaneous or delayed implant placement. The height of the graft material decreased mainly in the first 12 months, and continued until stabilization after 5 years, with no significant variations thereafter.

Key words:Sinus lift, pristine bone, native bone, dental implants, marginal bone loss, radiological study, implant survival, implant success.

Dental Implant Rehabilitation in Patients Suffering from Mucocutaneous Diseases: A Systematic Review and Meta-Analysis

Objective:

Dental implantations are widely used for oral rehabilitation of edentulous patients. Despite high success rate, there are some risk factors that have been associated with failures. Oral mucocutaneous diseases are one of these risk factors for implant insertion due to the immunosuppressive therapy.

There are limited studies that have dealt with the subject of dental implantology in oral mucosal disorders mainly with patients with oral lichenplanus, pemphigoid, pemphigus vulgaris, and systemic lupus erythematosus. In order to assess the result of implantations in such patients, we have reviewed the studies.

Materials and Methods:

We searched PubMed, Science Direct, and Cochrane databases for articles published from Jan 2000 to Dec 2017, using key search word “dental implants”, “oral lichen planus”, “pemphigoid”, “pemphigus vulgaris” and ”systemic lupus erythematosus”.

Results:

The random effects analysis result shows overall failure rates of 22% in patients with oral lichen planus. A systematic review revealed some failures that are not definitely related to these diseases.

Conclusion:

Due to the lack of adequate studies, a meta-analysis was only possible for oral lichen planus. Presently, there is no definite guideline regarding the placement of implant in patients suffering from mucocutaneous diseases; nevertheless, we should always consider that these patients are specific cases and need more attention in the first step of treatment and follow-ups. So there is a need to further clinical studies in order to evaluate more risk factors accurately and make a definitive conclusion.

The use of mineralized bone allograft as a single grafting material in maxillary sinus lifting with severely atrophied alveolar ridge (1-3 mm) and immediately inserted dental implants. A 3- up to 8-year retrospective study

OBJECTIVE

The primary aim of our study was to evaluate the efficacy of mineralized bone allograft alone in sinus floor augmentation with simultaneous implant placement in cases with severe atrophy of the residual maxillary bone (bone height < 4 mm).

METHODS

Thirty-five dental implants were placed in 29 patients who underwent sinus augmentation via traditional lateral window technique from 2008 to 2013. Patients with residual alveolar height between 1 and 3 mm at the site of implantation were included in the study. The height of residual bone was initially estimated by plain panoramic X-ray and reevaluated intraoperatively by precise micrometric measurement at the site of implantation. Implants of 13 mm height and 3.5 or 4.3 mm in diameter were inserted simultaneously. Mineralized bone allograft was used alone to augment the sinus floor.

RESULTS

No wound dehiscence was recorded. In one case there was a postoperative site infection which subsided with antibiotics without implant failure. One implant migrated during the postoperative period to the maxillary sinus and was removed. One implant failed. The remaining 33 implants were successfully loaded. Follow-up ranged from 3 to 8 years.

CONCLUSIONS

Maxillary sinus lift in severely absorbed alveolar ridges with simultaneous implant placement could be safely performed using mineralized allograft alone, rendering the procedure less invasive and less time-consuming.

Analysis of mineral apposition rates during alveolar bone regeneration over three weeks following transfer of BMP-2/7 gene via in vivo electroporation

Alveolar bone is not spontaneously regenerated following trauma or periodontitis. We previously proposed an animal model for new alveolar bone regeneration therapy based on the non-viral BMP-2/7 gene expression vector and in vivo electroporation, which induced the formation of new alveolar bone over the course of a week. Here, we analysed alveolar bone during a period of three weeks following gene transfer to periodontal tissue. Non-viral plasmid vector pCAGGS-BMP-2/7 or pCAGGS control was injected into palatal periodontal tissue of the first molar of the rat maxilla and immediately electroporated with 32 pulses of 50 V for 50 msec. Over the following three weeks, rats were double bone-stained by calcein and tetracycline every three days and mineral apposition rates (MAR) were measured. Double bonestaining revealed that MAR of alveolar bone was at similar level three days before BMP-2/7 gene transfer as three days after gene transfer. However, from 3 to 6 days, 6 to 9 days, 9 to 12 days, 12 to 15 days, 15 to 18 days, and 18 to 20 days after, MARs were significantly higher than prior to gene transfer. Our proposed gene therapy for alveolar bone regeneration combining nonviral BMP-2/7 gene expression vector and in vivo electroporation could increase alveolar bone regeneration potential in the targeted area for up to three weeks.

Bone augmentation as an adjunct to dental implant rehabilitation in patients with diabetes mellitus: A review of literature

The aim of the present article is to review the success of bone augmentation performed as an adjunct to dental implant rehabilitation in patients with diabetes mellitus. A literature review was conducted in PubMed on this topic, which yielded a total of 102 publications. For inclusion, publications had to be human studies, written in English language and should report on the success of bone augmentation as an adjunct to dental implant rehabilitation in diabetic patients. After screening the titles and abstracts, 11 full texts publications were obtained, of which seven were included in the review. These studies provided data on various bone augmentation techniques such as sinus floor elevation (SFE), guided bone regeneration (GBR), and onlay bone grafting. Even though the current review revealed that there are not many studies reporting data relevant to the analyzed topic, the data obtained suggests that; (1) staged GBR technique should be considered more feasible and predictable for bone augmentation, (2) clinicians must take meticulous care when planning and conducting SFE, and (3) block bone augmentation technique should be avoided.

Risk Factors in Early Implant Failure: A Meta-Analysis

BACKGROUND

Clinicians should be able to weigh the role of the main risk factors associated with early implant failure.

PURPOSE

The aim of this meta-analysis was to assess the influence of different patient-related and implant-related risk factors on the occurrence of early implant failure.

MATERIALS AND METHODS

In July, 2014 the main electronic databases were searched for studies reporting on early failures. Relevant papers were selected by 2 independent authors using predefined selection criteria. Three authors independently scored the included studies for quality assessment. The estimated odds ratios of the main risk factors from the selected papers were subjected to meta-analysis.

RESULTS

Nine studies were included. A total of 18,171 implants were meta-analyzed, of which 10,921 were analyzed for smoking, 15,260 for implant diameter, 16,075 for implant length, and 16,711 for implant location (maxilla vs mandible). The main significant risk factors for early implant failures were the smoking habit (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.3, 2.3), implants shorter than 10 mm (OR, 1.6; 95% CI, 1.2, 2.2) and implants placed in the maxilla (OR, 1.3; 95% CI, 1.0, 1.6).

CONCLUSIONS

Clinicians should be aware of the increased risk of early failure in the presence of smokers, implants with reduced length, and implant-supported maxillary rehabilitation.

An oral multispecies biofilm model for high content screening applications

Peri-implantitis caused by multispecies biofilms is a major complication in dental implant treatment. The bacterial infection surrounding dental implants can lead to bone loss and, in turn, to implant failure. A promising strategy to prevent these common complications is the development of implant surfaces that inhibit biofilm development. A reproducible and easy-to-use biofilm model as a test system for large scale screening of new implant surfaces with putative antibacterial potency is therefore of major importance. In the present study, we developed a highly reproducible in vitro four-species biofilm model consisting of the highly relevant oral bacterial species Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar and Porphyromonas gingivalis. The application of live/dead staining, quantitative real time PCR (qRT-PCR), scanning electron microscopy (SEM) and urea-NaCl fluorescence in situ hybridization (urea-NaCl-FISH) revealed that the four-species biofilm community is robust in terms of biovolume, live/dead distribution and individual species distribution over time. The biofilm community is dominated by S. oralis, followed by V. dispar, A. naeslundii and P. gingivalis. The percentage distribution in this model closely reflects the situation in early native plaques and is therefore well suited as an in vitro model test system. Furthermore, despite its nearly native composition, the multispecies model does not depend on nutrient additives, such as native human saliva or serum, and is an inexpensive, easy to handle and highly reproducible alternative to the available model systems. The 96-well plate format enables high content screening for optimized implant surfaces impeding biofilm formation or the testing of multiple antimicrobial treatment strategies to fight multispecies biofilm infections, both exemplary proven in the manuscript.

Analysis of implant-failure predictors in the posterior maxilla: a retrospective study of 1395 implants

The aim of this study was to analyze predictors for dental implant failure in the posterior maxilla. A database was created to include patients being treated with dental implants posterior to the maxillary cuspids. Independent variables thought to be predictive of potential implant failure included (1) sinus elevation, (2) implant length, (3) implant diameter, (4) indication, (5) implant region, (6) timepoint of implant placement, (7) one-vs. two-stage augmentation, and (8) healing mode. Cox regression analysis was used to evaluate the influence of predictors 1-3 on implant failure as dependent variable. The predictors 4-9 were analyzed strictly descriptively. The final database included 592 patients with 1395 implants. The overall 1- and 5-year implant survival rates were 94.8% and 88.6%, respectively. The survival rates for sinus elevation vs. placement into native bone were 94.4% and 95.4%, respectively (p = 0.33). The survival rates for the short (<10 mm), the middle (10-13 mm) and the long implants (>13 mm) were 100%, 89% and 76.8%, respectively (middle-vs. long implants p = 0.62). The implant survival rates for the small- (<3.6 mm), the middle- (3.6-4.5 mm) and the wide diameter implants (>4.5 mm) were 92.5%, 87.9% and 89.6%, respectively (p = 0.0425). None of the parameters evaluated were identified as predictor of implant failure in the posterior maxilla.

Posterior partially edentulous jaws, planning a rehabilitation with dental implants

AIM: To discuss important characteristics of the use of dental implants in posterior quadrants and the rehabilitation planning.

METHODS: An electronic search of English articles was conducted on MEDLINE (PubMed) from 1990 up to the period of March 2014. The key terms were dental implants and posterior jaws, dental implants/treatment planning and posterior maxilla, and dental implants/treatment planning and posterior mandible. No exclusion criteria were used for the initial search. Clinical trials, randomized and non randomized studies, classical and comparative studies, multicenter studies, in vitro and in vivo studies, case reports, longitudinal studies and reviews of the literature were included in this review.

RESULTS: One hundred and fifty-two articles met the inclusion criteria of treatment planning of dental implants in posterior jaw and were read in their entirety. The selected articles were categorized with respect to their context on space for restoration, anatomic considerations (bone quantity and density), radiographic techniques, implant selection (number, position, diameter and surface), tilted and pterygoid implants, short implants, occlusal considerations, and success rates of implants placed in the posterior region. The results derived from the review process were described under several different topic headings to give readers a clear overview of the literature. In general, it was observed that the use of dental implants in posterior region requires a careful treatment plan. It is important that the practitioner has knowledge about the theme to evaluate the treatment parameters.

CONCLUSION: The use of implants to restore the posterior arch presents many challenges and requires a detailed treatment planning.

Key local and surgical factors related to implant failure

The concept of osseointegration has revolutionized the treatment options for the replacement of missing teeth in both partially and completely edentulous patients. Dental implants are widely used because clinical practice and studies have documented its successful outcomes. However, implants can occasionally fail, and such failures can be classified as early or late. Measures that can aid in the early recognition of failing osseointegrated implants are needed, as are measures that can facilitate appropriate treatment methods aimed at saving failing implants by determining the probable etiologic factors. This article summarizes our current understanding of the local factors that can be linked to implant failure.

Lactotransferrin Gene (LTF) Polymorphisms and Dental Implant Loss: A Case-Control Association Study

BACKGROUND

Dental implants have been widely used to replace missing teeth, accomplishing aesthetics and function. Due to its large use worldwide, the small percentage of implant loss becomes significant in number of cases. Lactotransferrin (LTF) is a pleiotropic protein, expressed in various body tissues and fluids, which modulates the host immune-inflammatory response and bone metabolism, and might be involved in dental implant osseointegration. Recently, a few studies have been investigating genetic aspects underlying dental implant failure.

PURPOSE

This case-control study aimed to investigate the association of genetic markers (tag SNPs) in LTF gene and clinical parameters with dental implant loss.

MATERIAL AND METHODS

278 patients, both sexes, mean age 51 years old, divided into 184 without and 94 with implant loss, were genotyped for sixteen tag SNPs, representative of the whole LTF gene. Also, clinical oral and systemic parameters were analyzed. Univariate and Multivariate Logistic Regression model were used to analyze the results (p < .05).

RESULTS

No association was found between the tag SNPs and implant loss in the study population. Clinical association was found with medical treatment, hormonal reposition, edentulism, number of placed implants, plaque, calculus, and mobility.

CONCLUSION

Clinical variables, but not LTF gene polymorphisms, were associated with implant loss.

Long-term survival rate of implants placed in conjunction with 246 sinus floor elevation procedures: results of a 15-year retrospective study

OBJECTIVES

The aim of the present long-term study was to retrospectively evaluate the survival rate of implants placed in regenerated maxillary sinuses and to assess the influence of hypothetical predictors of implant failure.

METHODS

A database including 218 patients who received dental implants after sinus lift procedures was analyzed. The following variables were systematically included and evaluated: type of graft material used, number of surgeries performed, and use of membranes to cover the lateral antrostomy and/or to repair accidental Schneiderian membrane perforations. The Kaplan-Meier estimator was used for comparisons among the groups.

RESULTS

A total of 589 dental implants were positioned in 246 grafted sinuses and were in function for 3-186 months. The Kaplan-Meier cumulative survival rate was 98.3% after 15.5 years of follow-up. All implant losses occurred within 52 months (4.3 years) after augmentation. According to the log-rank test, no statistically significant difference was shown between each patient/implant variable (p>0.05).

CONCLUSIONS

Despite the limitations inherent in this type of study, no statistically significant differences between the groups could be found. Intraoperative Schneiderian membrane perforations did not affect the outcome of the implants positioned.

CLINICAL SIGNIFICANCE

The present long-term study is intended as a reference for clinicians approaching sinus floor elevation surgery in order to provide them with relevant operative findings. Since all the drawbacks occurred within the first 5 years, medium-term follow-up studies could be suitable for further retrospective evaluations.

A clinical prospective study on alveolar bone augmentation and dental implant success in patients with type 2 diabetes

OBJECTIVES

The objective of this prospective, controlled clinical study was to determine the outcomes of dental implant therapy with staged guided bone regeneration procedures in patients with type 2 diabetes.

PATIENTS AND METHODS

Twenty-four patients were included in the study. Half of the patients were diagnosed with type 2 diabetes mellitus (group 1) while the other half (group 2) of the patients consisted of patients without diabetes. The edentulous maxillary anterior/premolar regions with sufficient vertical height but inadequate horizontal width were treated with staged guided bone regeneration technique and with one or two implant-supported fixed restorations. The patients were followed up at least for 12 months. The parameters that were evaluated were radiographic evaluations on CBCT images and periapical radiographs, histomorphometric analysis, resonance frequency analysis (RFA) and wound-healing parameters. The data were analyzed statistically.

RESULTS

A total of 43 implants were placed in 24 patients (22 implants in group 1 and 21 implants in group 2). The survival rates of implants were 100% for both groups. The success rate of implants was 95% for group 1 and 100% for group 2. None of the parameters including CBCT findings, RFA values, success rates and wound-healing scores showed a significant difference between the two groups.

CONCLUSION

Staged guided bone regeneration is a feasible augmentation procedure for the treatment of horizontal bone deficiencies of the maxillary anterior/premolar regions in well-controlled type 2 diabetic patients.

Treatment of the edentulous atrophic maxilla using zygomatic implants: evaluation of survival rates over 5-10 years

The aim of this retrospective observational cohort study was to analyse and report the 5-10-year survival rates of endosseous zygomatic implants used in the rehabilitation of the atrophic maxilla. Forty-three consecutive zygomatic implant placements in 25 patients were evaluated over a 5-10-year period. All zygomatic implant surgery was carried out under general anaesthesia. Nobel Biocare zygomatic machined-surface implants were used, and placement was undertaken using the modified sinus slot method. The main outcome measures and determinants for success were survival of the restored implants and the proportion of originally planned prostheses delivered to patients. Of the 25 patients treated, 12 were male and 13 were female; 19 were non-smokers, and the mean age at time of surgery was 64 years. Patients were treatment-planned for implant-retained bridgework, a removable prosthesis retained by fixed cast gold or milled titanium beams, or magnet-retained removable prostheses. A combination of zygomatic and conventional implants was used in all but one patient. In this study it was shown that the overall success rate for zygomatic implants was 86%, with six of the implants either failing to integrate or requiring removal due to persistent infection associated with the maxillary sinus. All patients received their planned prosthesis, although in six cases the method of retention required modification. This study illustrates that zygomatic implants are a successful and important treatment option when trying to restore the atrophic maxilla, with the potential to avoid additional augmentation/grafting procedures and resulting in a high long-term success rate.

Radiographic outcomes of transcrestal sinus floor elevation performed with a minimally invasive technique in smoker and non-smoker patients

OBJECTIVES

To evaluate the association between smoking status and the outcomes of transcrestal sinus floor elevation (tSFE) performed with a minimally invasive technique (Smart Lift).

METHODS

Forty-five implants were placed in 25 non-smoker (NS) and 20 smoker (S) patients in conjunction with the tSFE procedure. In all cases, an additional graft, chosen among different hydroxyapatite-based or ß-tricalcium phosphate-based biomaterials, was pushed into the sinus by gradual increments. Immediately after surgery, residual bone height, implant penetration into the sinus, extent of sinus lift (SL) and the height of the graft apical to the implant apex (aGH) were assessed on periapical radiographs. At 6 months after surgery, SL and aGH were reassessed.

RESULTS

(i) The Smart Lift procedure resulted in substantial 6-month SL and aGH in both treatment groups; (ii) smoking status did not significantly affect the 6-month radiographic outcomes; (iii) a similarly low incidence of intra- and postoperative complications was observed in NS and S patients.

CONCLUSIONS

Smoking has a limited impact on the outcomes of tSFE performed with the Smart Lift technique.

Immediate versus conventional loading of post-extraction implants in the edentulous jaws

PURPOSE

This retrospective study deals with the issue of how to realize the transition from a failing dentition to an implant-supported prosthesis. The main aim was to assess the reliability of immediate implant and immediate loading (IL) protocols in the edentulous jaws. A further aim was to investigate the role of patient-related, implant-related, and surgery-related secondary variables in the occurrence of implant failure.

MATERIALS AND METHODS

Patients with at least a 4-year post-loading follow-up undergoing the transition from a failing dentition to an implant-supported prosthesis were retrospectively investigated. Primary variables of implant failure were immediate placement and IL. Secondary variables were categorized as demographic, anatomic, site, and prosthetically related. Cumulative survival rates (CSRs) were compared using the Kaplan-Meier survival estimate method. Predictors of failure were included in a multivariate Cox regression model to evaluate the simultaneous effects of multiple covariates and control for correlated observation. Crestal bone loss was also measured at the delayed and the immediately loaded implants.

RESULTS

Five hundred nineteen implants rehabilitating 91 jaws in 80 patients were followed. The Kaplan-Meier survival estimate method showed that immediate implant and IL decreased the CSR significantly in the maxilla but not in the mandible. Some secondary variables were found to affect the CSR: maxillary location, age over 70 years, prostheses supported by only immediate implants or a majority of them, temporary cementation, implant diameter, and length. Crestal bone loss was not significantly related to the outcomes.

CONCLUSIONS

The present data may provide clinical recommendations to the practitioner treating the transitional patient. In the mandible, the use of immediate implants and IL does not increase the failure rate. In the maxilla however, combining immediate placement and IL may significantly increase the failure rate.

Survival of implants placed with the osteotome technique: an update

A literature review is made to analyze the survival of implants placed with the osteotome technique. A PubMed search was made based on the key words "osteotome AND dental implants", corresponding to publications between 1998-2008. The inclusion criteria were: a) a minimum of 10 patients; b) a minimum follow-up of 6 months; c) implants placed using the osteotome technique with or without indirect sinus lift; and d) specification of the implant number and survival rate. Sixty-four articles were identified, of which 20 met the inclusion criteria. A total of 2006 implants were placed in 1312 patients using the osteotome technique. The duration of follow-up after prosthetic loading ranged from 6-144 months. Indirect sinus lift was carried out in all but one of the studies. The residual crest height ranged from 2.8-12 mm, with a mean gain in bone after sinus lift of 2.5-5.1 mm. The time from implant placement to prosthetic loading varied from 1.5-9 months. The percentage implant survival rate was 85.1-100%. The survival rate of implants placed with the osteotome technique is high and does not differ with respect to implant placement with the conventional technique.

A critical review of diabetes, glycemic control, and dental implant therapy

OBJECTIVES

To systematically examine the evidence guiding the use of implant therapy relative to glycemic control for patients with diabetes and to consider the potential for both implant therapy to support diabetes management and hyperglycemia to compromise implant integration.

MATERIAL AND METHODS

A systematic approach was used to identify and review clinical investigations directly assessing implant survival or failure for patients with diabetes. A MEDLINE (PubMED) database search identified potential articles for inclusion using the search strategy: (dental implants OR oral implants) AND (diabetes OR diabetic). Inclusion in this review required longitudinal assessments including at least 10 patients, with included articles assessed relative to documentation of glycemic status for patients.

RESULTS

Although the initial search identified 129 publications, this was reduced to 16, for inclusion. Reported implant failure rates for diabetic patients ranged from 0% to 14.3%. The identification and reporting of glycemic control was insufficient or lacking in 13 of the 16 studies with 11 of these enrolling only patients deemed as having acceptable glycemic control, limiting interpretation of findings relative to glycemic control. Three of the 16 studies having interpretable information on glycemic control failed to demonstrate a significant relationship between glycemic control and implant failure, with failure rates ranging from 0% to 2.9%.

CONCLUSIONS

Clinical evidence is lacking for the association of glycemic control with implant failure while support is emerging for implant therapy in diabetes patients with appropriate accommodations for delays in implant integration based on glycemic control. The role for implants to improve oral function in diabetes management and the effects of hyperglycemia on implant integration remain to be determined.

Early dental implant failure: risk factors

The objective of this prospective study was to estimate the incidence of early loss of dental implants and the potential risk factors. The predictive variables were classified as being patient, implant, anatomical, or operation-specific. The outcome variable was early failure of the implant. The significance of differences was assessed using bivariate analyses, and then a multivariate logistic regression model to identify independent predictors for early loss of implants. A total of 169 patients, 116 women and 53 men, mean age 47 (range 16-80) years, had 399 implants inserted. Fifteen implants were lost in 14 patients (8%). The early loss of dental implants was significantly associated with width of keratinised gingiva (p=0.008), the use polyglactin sutures (p=0.048), and the use of narrow implants (p=0.035). Multivariate logistic regression analysis established the significance of narrow keratinised gingiva (OR=4.7, p=0.005) and the use of polyglactin sutures (OR=3.8, p=0.042), which we conclude are probably the strongest predictors of early failure of implants.

Implant survival after sinus elevation with Straumann(®) BoneCeramic in clinical practice: ad-interim results of a prospective study at a 15-month follow-up

OBJECTIVES

Elevation of the sinus floor with Straumann(®) BoneCeramic gave promising results in some recent clinical studies. However, no study has evaluated the long-term survival of implants after this surgical procedure. We are conducting a prospective, observational study to evaluate the long-term implant survival after this surgical procedure in clinical practice. We present here an ad-interim report of this study, including only patients with ≥12-month follow-up after implant placement.

METHODS

This prospective cohort study will last until a follow-up of 5 years will be achieved in at least 50 patients. Inclusion criteria are: age ≥18 years; presence of a maxillary partial unilateral or bilateral edentulism involving the premolar/molar areas; elective rehabilitation with oral implants; and physical capability to tolerate conventional surgical and restorative procedures. Patients are treated according to the two-stage technique and the preparation is filled with Straumann(®) BoneCeramic. Implant survival is evaluated every 3 months for the first 2 years, and then every 6 months up to 5 years.

RESULTS

Fifteen patients are considered in this ad-interim analysis. Mean follow-up was 14.9 ± 3.1 (range: 6-18 months). In total, three implants failed, in one single patient, 6 months after insertion. The cumulative implant survival rate was 92.5% (95% confidence interval: 83.0-100%).

CONCLUSIONS

This ad-interim analysis suggests that the elevation of the sinus floor with Straumann(®) BoneCeramic may be an effective clinical option over >1-year follow-up. A longer term follow-up will allow a deeper characterization of these preliminary findings.

Outfracture osteotomy on lateral maxillary wall as a modified sinus graft technique

PURPOSE

The purpose of this study was to provide feasibility of a new technique of sinus graft: outfracture osteotomy sinus graft.

MATERIALS AND METHODS

The author modified the window opening method from the original trapdoor technique to an outfracturing and readaptation technique. It provides a few advantages in dental implant treatment of atrophic maxillary posterior edentulous alveolar ridges: 1) in combined cases of height and width problems; 2) in cases with anatomic problems such as sinus septum, thick lateral sinus wall, and intrabony bleedings; 3) possible use of the outfractured bony segment as a covering membrane.

RESULTS

The follow-up of 34 patients (40 cases; 6 bilateral cases) revealed good results without a case of graft failure and showed excellent survival and function of the dental implants.

CONCLUSION

The sinus graft technique was modified as the author outfractured and readapted the bony lateral window, with several advantages as mentioned above. This new outfracture osteotomy sinus graft technique has excellent results as an alternative to the original trapdoor technique.