Impact of local and systemic factors on the incidence of oral implant failures, up to abutment connection

Biomimetic surface modification of titanium surfaces for early cell capture by advanced electrospinning

The time required for osseointegration with a metal implant having a smooth surface ranges from three to six months. We hypothesized that biomimetic coating surfaces with poly(lactic-co-glycolic acid) (PLGA)/collagen fibers and nano-hydroxyapatite (n-HA) on the implant would enhance the adhesion of mesenchymal stem cells. Therefore, this surface modification of dental and bone implants might enhance the process of osseointegration. In this study, we coated PLGA or PLGA/collagen (50:50 w/w ratio) fiber on Ti disks by modified electrospinning for 5 s to 2 min; after that, we further deposited n-HA on the fibers. PLGA fibers of fiber diameter 0.957 ± 0.357 µm had a contact angle of 9.9 ± 0.3° and PLGA/collagen fibers of fiber diameter 0.378 ± 0.068 µm had a contact angle of 0°. Upon n-HA incorporation, all the fibers had a contact angle of 0° owing to the hydrophilic nature of n-HA biomolecule. The cell attachment efficiency was tested on all the scaffolds for different intervals of time (10, 20, 30 and 60 min). The alkaline phosphatase activity, cell proliferation and mineralization were analyzed on all the implant surfaces on days 7, 14 and 21. Results of the cell adhesion study indicated that the cell adhesion was maximum on the implant surface coated with PLGA/collagen fibers deposited with n-HA compared to the other scaffolds. Within a short span of 60 min, 75% of the cells adhered onto the mineralized PLGA/collagen fibers. Similarly by day 21, the rate of cell proliferation was significantly higher (p ⩽ 0.05) on the mineralized PLGA/collagen fibers owing to enhanced cell adhesion on these fibers. This enhanced initial cell adhesion favored higher cell proliferation, differentiation and mineralization on the implant surface coated with mineralized PLGA/collagen fibers.

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.

Removal torque analysis of implants in rabbit tibia after topical application of simvastatin gel

The aim of this study was to evaluate the effects of topical application of simvastatin gel (7.5 mg) on the removal torque of titanium implants in the rabbit tibia. A total of 32 surgeries were performed on 16 New Zealand rabbits for the placement of 2 implants in 1 tibia of each rabbit. Only 1 of the surgical defects was injected with 30 mg/mL of simvastatin gel before implant placement. The initial torque was set at 20 N.cm, and removal torque testing was performed 28 and 56 days postoperatively with a Tonishi torque wrench. Surgical defects were divided into 4 groups: group IG-28 (test, 28 days), group IG-56 (test, 56 days), group I-28 (control, 28 days), and group I-56 (control, 56 days). Removal torque values were higher in group IG-56 than in groups IG-28, I-28, and I-56 (P < .05). Groups IG-28, I-28, and I-56 showed similar values (P > .05). Removal torque force increased under the influence of simvastatin, indicating that topical administration of a 7.5-mg dose of simvastatin gel is effective in improving the torque force required to remove implants inserted in the rabbit tibia.

[Diabetes mellitus and periodontitis. Bidirectional relationship and clinical implications. A consensus document]

Diabetes and periodontitis are chronic diseases with an increasing prevalence in the German population. There is a bi-directional relationship between both diseases. Diabetes promotes the occurrence, the progression and the severity of periodontitis. Periodontitis complicates the glycemic control of diabetes, increases the risk of diabetes-associated complications and possibly even of its onset. In view of the existing evidence, that is still not sufficiently communicated within the medical community, an expert panel consisting of four diabetologists and four periodontists has addressed the following questions: What is the effect of diabetes mellitus on periodontitis and on periodontal therapy? What is the effect of periodontitis on diabetes mellitus? What are the practical consequences, that result for interdisciplinary treatment strategies? The treatment of periodontal infections should become an integral part of the management of diabetes, whereas glycemic control is a prerequisite for successful periodontal therapy.

Peri-implantitis and late implant failures in postmenopausal women: a cross-sectional study

AIM

Systemic bone loss is a major cause of fractures in postmenopausal women and may also affect the jawbone; however, its consequences on the success of dental implants remain poorly understood.

MATERIALS AND METHODS

In this cross-sectional study, the relation between self-reported osteoporosis and the success rate of dental implants in an adult female population was evaluated. The primary outcome parameters were the occurrence of peri-implantitis and late implant failures. Women with unknown bone status were excluded from the study. The potential confounders age, recipient site, smoking, periodontal disease and time of loading were recorded.

RESULTS

Data from 203 women with a mean age of 63 ± 9 years and 967 dental implants were investigated. The patients were classified according to their medical history into one of three groups: osteoporosis (47 women), osteopenia (16 women) and healthy controls (140 women). Patients with unknown bone status (n=26) were excluded. The multi-level statistical analysis showed no association between peri-implantitis [odds ratio (OR) 2.1; p=0.6] or implant failure [hazards ratio (HR) 2.5; p=0.2] and systemic bone loss.

CONCLUSIONS

No relation was found between osteoporosis and peri-implantitis in an adult female population.

The effect of hierarchical micro/nanosurface titanium implant on osseointegration in ovariectomized sheep

Hydrofluoric etching and anodized hierarchical micro/nanotextured surface titanium implant was placed in mandibles of ovariectomized sheep for 12 weeks, and it showed improved osseointegration by resonance frequency analysis (RFA), microcomputed tomography (micro-CT) evaluation, histomorphometry, and biomechanical test.

INTRODUCTION

This study aimed to investigate the effects of micro/nanotextured titanium implant on osseointegration in ovariectomized (OVX) sheep.

METHODS

The hierarchical micro/nanotextured surface of titanium implant was fabricated by acid in 0.5% (w/v) hydrofluoric (HF) and anodized in HF acid electrolytes with a DC power of 20 V, and the machined surface implants with no treatment served as control group. The implants were placed in mandibles of OVX sheep, respectively. Twelve weeks after implantation, RFA, microcomputed tomography, histomorphometry, and biomechanical tests were applied to detect the osseointegration of the two groups.

RESULTS

The implant stability quotient (ISQ) values, the maximum pull-out forces, and the bone-implant contact (BIC) were 65.5 ± 6.3, 490.6 ± 72.7 N, and 58.31 ± 5.79% in the micro/nanogroup and 58.3 ± 8.9, 394.5 ± 54.5 N, and 46.85 ± 5.04% in the control group, respectively. There was no significant difference between the two groups in ISQ values (p > 0.05), but in the micro/nanogroup, the maximal pull-out force and the BIC were increased significantly (p < 0.05 or p < 0.01). Micro-CT analysis showed that the bone volume ratio and the trabecular number increased significantly (p < 0.01), and the trabecular separation decreased significantly (p < 0.05) in the micro/nanogroup.

CONCLUSION

Implant modification by HF acid etching and anodization to form a hierarchical micro/nanotextured surface could improve titanium implant osseointegration in OVX sheep 12 weeks after implantation.

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.

The effects of cortical bone thickness and trabecular bone strength on noninvasive measures of the implant primary stability using synthetic bone models

PURPOSE

This study investigated how the primary stability of a dental implant as measured by the insertion torque value (ITV), Periotest value (PTV), and implant stability quotient (ISQ) is affected by varying thicknesses of cortical bone and strengths of trabecular bone using synthetic bone models.

MATERIALS AND METHODS

Four synthetic cortical shells (with thicknesses of 0, 1, 2, and 3 mm) were attached to four cellular rigid polyurethane foams (with elastic moduli of 137, 47.5, 23, and 12.4 MPa) and one open-cell rigid polyurethane foam which mimic the osteoporotic bone (with an elastic modulus 6.5 MPa), to represent the jawbones with various cortical bone thicknesses and strengths of trabecular bone. A total of 60 bone specimens accompanied with implants was examined by a torque meter, Osstell resonance frequency analyzer, and Periotest electronic device. All data were statistically analyzed by two-way analysis of variance. In addition, second-order nonlinear regression was utilized to assess the correlations of the primary implant stability with the four cortex thicknesses and five strengths of trabecular bone.

RESULTS

ITV, ISQ, and PTV differed significantly (p < .05) and were strongly correlated with the thickness of cortical bone (R(2) > 0.9) and the elastic modulus of trabecular bone (R(2) = 0.74-0.99).

CONCLUSIONS

The initial stability at the time of implant placement is influenced by both the cortical bone thickness and the strength of trabecular bone; however, these factors are mostly nonlinearly correlated with ITV, PTV, and ISQ. Using ITV and PTV seems more suitable for identifying the primary implant stability in osteoporotic bone with a thin cortex.

Multiple myeloma and bisphosphonate-related osteonecrosis of the mandible associated with dental implants

Multiple myeloma (MM) is a malignant plasma cell disorder and more than 30% of patients with this pathology develop osteolytic lesions in the jaw. Either pamidronate or zoledronic acid is recommended in patients with MM who have one or more lytic lesions. However, bisphosphonate-related osteonecrosis of the jaws (BRONJ) has been described as a complication associated with their use. Otherwise, the use of endosseous implants in oral rehabilitation is a well-established procedure, with good long-term success although systemic factors may affect the bone healing around dental implants. We report the first case reported of MM adjacent to a mandibular dental implant in a patient who developed BRONJ in the same area after intravenous zoledronate treatment. We discuss possible pathogeny of this particular and interesting phenomena.

Sex dependent regulation of osteoblast response to implant surface properties by systemic hormones

Background

Osseointegration depends on the implant surface, bone quality and the local and systemic host environment, which can differ in male and female patients. This study was undertaken in order to determine if male and female cells respond differently to titanium surfaces that have micron-scale roughness and if interactions of calciotropic hormones [1α,25(OH)₂D₃ and 17β-oestradiol (E₂)] and microstructured surfaces on osteoblasts are sex dependent.

Methods

Osteoblasts from 6-week old Sprague-Dawley rats were cultured on tissue culture polystyrene (TCPS) or on titanium (Ti) disks with two different surface topographies, a smooth pretreated (PT) surface and a coarse grit-blasted/acid-etched (SLA) surface, and treated with 1α,25(OH)₂D₃, E₂, or E₂ conjugated to bovine serum albumin (E₂-BSA).

Results

Male and female cells responded similarly to Ti microstructure with respect to cell number and levels of osteocalcin, transforming growth factor-β1, osteoprotegerin and prostaglandin E₂ in their conditioned media, exhibiting a more differentiated phenotype on SLA than on PT or TCPS. E₂ and E₂-BSA increased differentiation and local factor production, an effect that was microstructure dependent and found only in female osteoblasts. 1α,25(OH)₂D₃ increased osteoblast differentiation and local factor production in female and male cells, but the effect was more robust in male cells.

Conclusions

Male and female rat osteoblasts respond similarly to surface microstructure but exhibit sexual dimorphism in substrate-dependent responses to systemic hormones. Oestrogen affected only female cells while 1α,25(OH)₂D₃ had a greater effect on male cells. These results suggest that successful osseointegration in males and females may depend on the implant surface design and correct levels of calciotropic hormones.

Influence of bisphosphonates on alveolar bone loss around osseointegrated implants

The relationship between bisphosphonates (BP) and dental implant failure has not been fully elucidated. The purpose of this retrospective radiographic study was to examine whether patients who take BP are at greater risk of implant failure than patients not using those agents. Treatment records of 362 consecutively treated patients receiving endosseous dental implants were reviewed. The patient population consisted of 227 women and 135 men with a mean age of 56 years (range: 17-87 years), treated in the University at Buffalo Postgraduate Clinic from 1997-2008. Demographic information collected included age, gender, smoking status, as well as systemic conditions and medication use. Implant characteristics reviewed included system, date of placement, date of follow-up radiographs, surgical complications, number of exposed threads, and implant failure. The relationship between BP and implant failure was analyzed using generalized estimating equation (GEE) analysis. Twenty-six patients using BP received a total of 51 dental implants. Three implants failed, yielding success rates of 94.11% and 88.46% for the implant-based and subject-based analyses, respectively. Using the GEE statistical method we found a statistically significant (P  =  .001; OR  =  3.25) association between the use of BP and implant thread exposure. None of the other variables studied were statistically associated with implant failure or thread exposure. In conclusion, patients taking BP may be at higher risk for implant thread exposure.

Factors associated with failure of surface-modified implants up to four years of function

OBJECTIVES

The relative impact of innovative treatment concepts on the failure of surface-modified implants is not well understood. This retrospective study aimed to explore this using data obtained in a university postgraduate training center.

MATERIAL AND METHODS

Patients treated with implants for a variety of indications over a 3-year period were included. All implants had been at least 1 year in function. Clinical records were evaluated for implant failure and in reference to implant length/diameter/location, time from tooth loss to implant placement, bone condition (native/grafted), surgical protocol (two-/one-stage), loading protocol (delayed/early/immediate), type of prosthesis (removable/fixed), surgeon's experience level (resident/trainee) and specialty (periodontist/oral surgeon). The impact of each covariate on failure was tested using the Fisher's exact test. Kaplan-Meier survival functions were constructed and Mantel-Cox log-rank tests were used to compare survival functions. To correct for possible interaction, Cox proportional Hazards regression was adopted.

RESULTS

Forty-one of 1,180 (3.5%) implants were lost in 34/461 (7.4%) patients (245 ♀, 216 ♂; mean age 51, range 18-90). Factors showing significant impact on failure on the basis of univariate analyses were implant location (p = .015), surgical protocol (p = .002), loading protocol (p = .002), surgeon's experience level (p = .035) and specialty (p = .001). When controlling for other covariates, only the loading protocol had a significant influence (p = .049) with early loading more prone to failure (p = .014) when compared with delayed loading. Immediate loading and delayed loading showed comparable implant survival (p = .311).

CONCLUSIONS

Implant therapy may be highly successful in a training center where inexperienced clinicians are strictly monitored and personally guided. Implant specific variables do not affect implant survival but early loading is a risk indicator for implant failure, whereas immediate loading is not.

Implant location and radiotherapy are the only factors linked to 2-year implant failure

SUBJECTS

The subjects in this retrospective case series were derived from a review of 700 patient files within the implant practice of the Department of Periodontology, University Hospital, Catholic University of Leuven. Inclusion criteria were met by 412 patients (240 females, 172 males) receiving a total of 1514 Nobel Biocare dental implants. These patients were included based on data availability for the time period 2 years after abutment surgery (considered to represent late implant failure).

KEY EXPOSURE/STUDY FACTOR

Given the concern of the authors to assess the probability of late implant failure among clinic patients with certain local and systemic factors, the potential factors were multiple. The local factors included the following: implant length and diameter, bone quality and quantity, insertion site, type of edentulism, antibiotic use perioperatively, dehiscence and/or perforation of the site during surgery, and stability at insertion (measured by Periotest values). The related health and behavioral factors included the following: medications, smoking (<10 cigarettes/day, 10-20 cigarettes/ day, >20 cigarettes/day), hypertension, ischemic cardiac problems, coagulation anomalies, gastric ulcers, thyroid disorders, hypercholesterolemia,rheumatoid arthritis, asthma, diabetes (types 1 and 2), Crohn's disease, and chemotherapy.

MAIN OUTCOME MEASURE

The primary outcome was described as "late implant failure." The current study, which follows a similar study on early implant failure, aims to identify negative influences on maintenance of integration. The authors used the clinical experience related to the 412 patients with 1514 implants to identify whether the observed failure rates were influenced by local and systemic factors. Failure was defined as "late" when occurring between abutment connection surgery and 2 years after this date. Patients/implants that were not available for this interval of time were not included. However, even when records were available, not all patient records provided all data sought.

MAIN RESULTS

Regarding local factors, the authors reported that implant diameter and location were relevant to late implant loss, whereas implant length was not (P value = .01, = .34, respectively; univariate generalized estimating equation [GEE] logistic regression). Regarding implant diameter, significantly more loss was noted for 5.00-mm implants when compared with the 4.00-mm or 4.75-mm implants. Failure related to location revealed that the maxilla compared with the mandible, posterior jaws compared with anterior jaws, and the posterior maxilla compared with all other oral locations were associated with more late failures (Table 1). Assessment of systemic factors revealed radiotherapy to be related to more late implant loss (P = .003). Neither systemic disease nor smoking exposure was associated with late failure.

CONCLUSIONS

The authors concluded that late implant failure was influenced by the local factor "implant location" and the systemic factor "radiotherapy." Neither smoking nor systemic health factors were found to adversely influence implant integration from abutment connection through 2 years' performance.

Zirconia: Established facts and perspectives for a biomaterial in dental implantology

Currently, zirconia is widely used in biomedical area as a material for prosthetic devices because of its good mechanical and chemical properties. Largely employed in clinical area for total hip replacement, zirconia ceramics (ZrO(2)) are becoming a prevalent biomaterial in dentistry and dental implantology. Although titanium is used in dental implantology currently, there is a trend to develop new ceramic-based implants as an alternative to monolithic titanium. This article reviews the evolution and development of zirconia through data published between 1963 and January 2008 in English language. Articles were identified via a MEDLINE search using the following keywords: zirconia, zirconia/biocompatibility, zirconia/osseointegration, zirconia/periointegration, zirconia/review, and zirconia/bacterial adhesion or colonization. This review of the literature aims at highlighting and discussing zirconia properties in biological systems for their future use in dental implantology. In conclusion, zirconia with its interesting microstructural properties has been confirmed to be a material of choice for the "new generation" of implants, thanks to its biocompatibility, osseoconductivity, tendency to reduce plaque accumulation, and interaction with soft tissues, which leads to periointegration. However, scientific studies are promptly needed to fulfill gaps like long-term clinical evaluations of "all zirconia implants," currently leading to propose an alternative use of "hybrid systems" (i.e., titanium screw with zirconia collar) and also bacterial colonization of zirconia. Moreover, there is a permanent need for consistent information about topography and chemistry of zirconia allowing easier cross-product comparisons of clinical devices.

Impact of local and systemic factors on the incidence of failures up to abutment connection with modified surface oral implants

AIM

This study aimed to assess the influence of systemic and local bone and intra-oral factors on the occurrence of early TiUnite implant failures.

MATERIAL AND METHODS

A total of 283 consecutive patients (187 females; mean age 56.2), who received a total of 720 TiUnite implants, at the Department of Periodontology of the University Hospital of the Catholic University of Leuven, were prospectively followed. The following aspects were particularly assessed: hypertension, cardiac problems, gastric problems, osteoporosis, hypo- or hyperthyroid, hypercholesterolaemia, asthma, diabetes types I or II, Crohn's disease, rheumatoid arthritis, chemotherapy, hysterectomy and intake of medication (antidepressants, steroids, hormone replacement), radiotherapy of the concerned area, breach of sterility during surgery, implant parameters, bone (quality, quantity, dehiscence or perforation), type of edentulism, antibiotics prescription, fenestration of the implant in the sinus/nasal cavity, immediate implant placement, apical lesion detection and insertion torque.

RESULTS AND CONCLUSION

A global failure rate of 1.9% was recorded. Owing to the very few failures, no definitive conclusion concerning statistical significance can be achieved. However, a tendency for more failures was noticed for apical lesions, vicinity with natural dentition, smoking, hormone replacement, gastric problems, Crohn's disease, diabetes I and radical hysterectomy.