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

A quantification of regenerated bone tissue in human sinus biopsies: influences of anatomical region, age and sex

OBJECTIVES

Sinus augmentation is a standard procedure to increase vertical bone supply for dental implants in the atrophic posterior maxilla. Despite the longstanding application of this method, information about some basic factors that could potentially influence bone regeneration after sinus augmentation is rare. The objective of this study was therefore to quantify the impact of the maxillary region (premolar/molar) and patients' age and sex on bone regeneration after sinus grafting.

MATERIAL AND METHODS

Sinus augmentation procedures were performed in 107 patients (66 female: 52.8 ± 11.0 years, 41 male: 50.6 ± 11.3 years). After 6 ± 1 months, 201 sinus biopsies were harvested and histomorphometrically analysed. Height (oldHt) and bone volume fraction of pristine bone (oldBV/TV), as well as the amount of new bone (newBV/TV) and bone-to-bone substitute contact (BBSC) in the augmentation area, were assessed.

RESULTS

In women, newBV/TV in the augmented sinus decreased significantly by 0.22 ± 0.08% per year. In men, no similar trend was observed. There were strong influences of the maxillary region and the dimensions of the host bone. In the premolar region, newBV/TV was 23.1 ± 7.9% and 25.1 ± 10.1%; in the molar region, newBV/TV averaged 20.4 ± 9.4% and 17.8 ± 8.8% for women and men, respectively. The greater the thickness of the wall of the sinus floor (mainly in the former premolar region), the greater was the amount of new bone tissue formed in the spaces in-between bone substitute particles.

CONCLUSIONS

These empirical results derived from a large human sample, link factors that influence the quality of biomaterial integration to the known clinical risks for the success of dental implants.

Smoking and dental implants: A systematic review and meta-analysis

OBJECTIVE

Recent studies implicate smoking as a significant factor in the failure of dental implants. This review aims to test the null hypothesis of no difference in the implant failure rates, risk of postoperative infection, and marginal bone loss for smokers versus non-smokers, against the alternative hypothesis of a difference.

DATA

Main search terms used in combination: dental implant, oral implant, smoking, tobacco, nicotine, smoker, and non-smoker.

SOURCES

An electronic search was undertaken in September/2014 in PubMed/Medline, Web of Science, Cochrane Oral Health Group Trials Register plus hand-searching.

STUDY SELECTION

Eligibility criteria included clinical human studies, either randomized or not. The search strategy resulted in 1432 publications, of which 107 were eligible, with 19,836 implants placed in smokers, with 1259 failures (6.35%), and 60,464 implants placed in non-smokers, with 1923 failures (3.18%).

CONCLUSIONS

The insertion of implants in smokers significantly affected the failure rates, the risk of postoperative infections as well as the marginal bone loss. The results should be interpreted with caution due to the presence of uncontrolled confounding factors in the included studies.

CLINICAL SIGNIFICANCE

Smoking is a factor that has the potential to negatively affect healing and the outcome of implant treatment. It is important to perform an updated periodic review to synthesize the clinical research evidence relevant to the matter.

Adenoviral vector-mediated overexpression of osteoprotegerin accelerates osteointegration of titanium implants in ovariectomized rats

This study investigated the efficacy of human osteoprotegerin (hOPG) transgene to accelerate osteointegration of titanium implant in ovariectomized (OVX) rats. Bone marrow stromal cells transduced with Ad-hOPG-EGFP could sustainedly express hOPG. Osteoclast precursor RAW264.7 cells treated by the hOPG were examined by tartrate-resistant acid phosphatase (TRAP) staining and bone slice resorption assay. The results showed differentiation and function of osteoclasts were significantly suppressed by hOPG in vitro. Ad-hOPG-EGFP was locally administered to the bone defect prior to implant placement in OVX and sham rats. After 3, 7, 28 days of implantation, the femurs were harvested for molecular and histological analyses. Successful transgene expression was confirmed by western blot and cryosectioning. A significant reduction in TRAP+ numbers was detected in Ad-hOPG-EGFP group. Real-time reverse transcriptase-PCR examination revealed that hOPG transgene markedly diminished the expression of cathepsin K and receptor activator for nuclear factor-κ B ligand in vivo. The transgene hOPG modification revealed a marked increasing osteointegration and restored implant stability in OVX rats (P<0.01), compared with the control groups (Ad-EGFP or sterilized phosphate-buffered saline) 28 days after implantation. In conclusion, hOPG via direct adenovirus-mediated gene transfer could accelerate osteointegration of titanium implants in OVX rats. Osteoprotegerin gene therapy may be an effective strategy to osteointegration of implants under osteoporotic conditions.

Osteoporosis and bisphosphonate-related osteonecrosis in a dental school implant patient population

PURPOSE

Studies have demonstrated an inconsistent association between implant failure and bone mineral density. The prevalence of osteoporosis in US adults has been reported to range from 5% to 10% in women and from 2% to 4% in men. The prevalence of bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) has been reported to range from 0% to 4.3% of patients taking oral BPs. The purpose of this study was to calculate the risk of dental implant loss and the incidence of BRONJ in patients with osteoporosis at the University of Kentucky College of Dentistry (UKCD).

MATERIALS AND METHODS

This study analyzed data collected from patients who had implants placed between 2000 and 2004 at UKCD. Data were gathered from patient interviews regarding implant survival and patient-satisfaction parameters, and interviews were conducted either chairside at a scheduled maintenance appointment or by telephone interview.

RESULTS

Among 203 patients who received 515 implants, the prevalence of osteoporosis was 23.3% for women and 1.2% for men. None of the 20 patients who reported a history of oral BP use exhibited BRONJ, and there were no implant failures in patients with a history of osteoporosis.

CONCLUSIONS

In this study, osteoporosis conferred no risk of implant failure, and oral BP therapy was not associated with BRONJ.

Determination of a critical size calvarial defect in senile osteoporotic mice model based on in vivo micro-computed tomography and histological evaluation

PURPOSE

To evaluate differences in the spontaneous healing capacity of senescence-prone inbred strains (SAMP6) and senescence-resistant inbred strains (SAMR1) and determine the critical defect size in a mouse model of senescence-accelerated osteoporosis.

METHODS

Unilateral full-thickness calvarial defects 2 or 4mm in diameter were made in 6-month-old male SAMP6 and SAMR1. Defects were evaluated in vivo by micro-CT at day 0 and 6 and 12 weeks postoperatively. Calvarial specimens were harvested at 12 weeks for hematoxylin and eosin staining, Masson's trichrome staining, and tartrate-resistant-acid-phosphatase (TRAP) staining.

RESULTS

Less new bone was observed in defects in SAMP6 compared to SAMR1 at 12 weeks postsurgery, with <5% healing in SAMP6 for both 2- and 4-mm defects compared to >5% healing in 2-mm defects in SAMRI (P<0.05). Histological analysis revealed dense connective tissue but little bone healing in 2- and 4-mm defects in SAMP6 and 4-mm defects in SAMR1. New bone was observed at the periphery of the 2-mm defects in SAMR1. Masson's trichrome staining also supported these findings. No obvious TRAP-positive cells were observed at the defect margins, but SAMP6 exhibited greater osteoclast numbers and surface areas in the diploë of contralateral bone compared to smaller osteoblast numbers and surface areas at the defect sites in SAMR1.

CONCLUSIONS

Defects of 2mm or larger in the cranium was critical-size or nonhealing defects in both SAMP6 and SAMR1. The differential findings on micro-CT and histomorphometry for the calvarial defect sites between SAMP6 and SAMR1 may imply different regenerative abilities of intramembranous ossification in these two strains.

Peri-implant evaluation of immediately loaded implants placed in esthetic zone in patients with diabetes mellitus type 2: a two-year study

OBJECTIVES

The aim of this study was to evaluate implant survival and primary stability parameters in patients with diabetes with different levels of glycosylated hemoglobin Alc (HbA1c) treated with immediate placement and provisionalization of implant-supported, single-tooth replacements over 2 years.

MATERIALS AND METHODS

Eighty-five patients were divided into three groups according to their HbA1c levels: 33 patients in Group 1 (<6, control group); 30 patients in Group 2 (6.1-8); and 22 patients in Group 3 (8.1-10). Each patient received one-one-piece implant in the anterior zone of the upper maxillary. The implant survival rate was analyzed for each group, together with three variables to evaluate the general state of peri-implant health: probe depth, bleeding on probing, marginal bone loss.

RESULTS

Marginal bone loss increased in relation with higher HbA1c levels. For marginal bone loss in Group 1, mean resorption values ranged from 0.51 after 6 months to 0.72 after 2 years in comparison with respective values of 1.33 and 1.92 in Group 3. This pattern was repeated for bleeding on probing, both parameters showing significant differences between groups. For bleeding on probing, mean bleeding levels varied from 0.36 in Group I at 6 months after implant placement, to 0.59 in Group 3 (P = 0.041 between the three groups). Peri-implant pocket depth showed the same tendency to increase in relation to HbA1C but differences between groups did not reach statistical significance.

CONCLUSIONS

Patients with diabetes can receive implant-based treatments with immediate loading safely, providing they present moderate HbA1c values.

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.

Immediate placement of implants into infected sites: a systematic review

BACKGROUND

Traditionally, before placing dental implants, the compromised teeth are removed and the extraction sockets are left to heal for several months. To preserve the alveolar bone level from the collapse caused by healing and to reduce treatment time in situations in which tooth extraction precedes implant placement, some clinicians began to install the implant immediately into the postextraction socket without waiting for the site to heal.

PURPOSE

The purpose of this study was to review the literature regarding treatment outcomes of immediate implant placement into sites exhibiting pathology after clinical procedures to perform the decontamination of the implant's site. The following questions were raised: Does the presence of periodontal or endodontic infection affect immediate implant placement success? What is suggested to address the infection in the socket prior to immediate placement?

MATERIALS AND METHODS

An electronic search in PubMed (U.S. National Library of Medicine, Bethesda, MD, USA) was undertaken in March 2013. The titles and abstracts from these results were read to identify studies within the selection criteria. Eligibility criteria included both animal and human studies, and excluded any review and case reports articles. The publication's intervention had to have been implant placement into a site classified as having an infection (periapical, endodontic, perioendodontic, and periodontal).

RESULTS

The search strategy initially yielded 706 references. Thirty-two studies were identified within the selection criteria, from which nine were case reports and review articles and were excluded. Additional hand-searching of the reference lists of selected studies yielded five additional papers.

CONCLUSIONS

The high survival rate obtained in several studies supports the hypothesis that implants may be successfully osseointegrated when placed immediately after extraction of teeth presenting endodontic and periodontal lesions, provided that appropriate clinical procedures are performed before the implant surgical procedure such as meticulous cleaning, socket curettage/debridement, and chlorhexidine 0.12% rinse. However, more randomized controlled clinical trials with a longer follow-up are required to confirm this procedure as a safe treatment. Moreover, the outcome measures were not related to the type of infection; the classification of infection was often vague and varied among the studies. The benefits of antibiotic solution irrigation and systemic antibiotic administration in such conditions are not yet proved and remain unclear.

Effectiveness of implant therapy analyzed in a Swedish population: early and late implant loss

Treatment outcomes in implant dentistry have been mainly assessed as implant survival rates in small, selected patient groups of specialist or university clinical settings. This study reports on loss of dental implants assessed in a large and randomly selected patient sample. The results were aimed at representing evaluation of effectiveness of implant dentistry. Using the national data register of the Swedish Social Insurance Agency, 4,716 patients were randomly selected. All had been provided with implant-supported restorative therapy in 2003. Patient files of 2,765 patients (11,311 implants) were collected from more than 800 clinicians. Information on patients, treatment procedures, and outcomes related to the implant-supported restorative therapy was extracted from the files. In total, 596 of the 2,765 subjects, provided with 2,367 implants, attended a clinical examination 9 y after therapy. Implant loss that occurred prior to connection of the supraconstruction was scored as an early implant loss, while later occurring loss was considered late implant loss. Early implant loss occurred in 4.4% of patients (1.4% of implants), while 4.2% of the patients who were examined 9 y after therapy presented with late implant loss (2.0% of implants). Overall, 7.6% of the patients had lost at least 1 implant. Multilevel analysis revealed higher odds ratios for early implant loss among smokers and patients with an initial diagnosis of periodontitis. Implants shorter than 10 mm and representing certain brands also showed higher odds ratios for early implant loss. Implant brand also influenced late implant loss. Implant loss is not an uncommon event, and patient and implant characteristics influence outcomes (ClinicalTrials.gov NCT01825772).

What is the impact of bisphosphonate therapy upon dental implant survival? A systematic review and meta-analysis

OBJECTIVE

A systematic review and meta-analysis are carried out to assess the scientific evidence that bisphosphonate therapy can decrease the success rate of dental implants.

MATERIAL AND METHODS

The PubMed (Medline) database was used to search for articles published up until February 22, 2014. The meta-analysis was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). The Newcastle-Ottawa scale (NOS) was used to assess study quality.

RESULTS

The combinations of search terms resulted in a list of 256 titles. Fourteen finally met the inclusion criteria and were thus selected for inclusion in the systematic review. Eight studies (six retrospective and two prospective) were included in the meta-analysis, with a total of 1288 patients (386 cases and 902 controls) and 4562 dental implants (1090 dental implants in cases and 3472 in controls). The summary odds ratio (OR = 1.43, P = 0.156) indicates that there is not enough evidence that bisphosphonates have a negative impact upon implant survival. According to the number need to harm (NNH), over 500 dental implants are required in patients receiving bisphosphonate treatment to produce a single implant failure.

CONCLUSION

Our results show that dental implant placement in patients receiving bisphosphonates does not reduce the dental implant success rate. On the other hand, such patients are not without complications, and risk evaluation therefore must be established on an individualized basis, as one of the most serious though infrequent complications of bisphosphonate therapy is bisphosphonate-related osteonecrosis of the jaws. Given the few studies included in our meta-analysis, further prospective studies involving larger sample sizes and longer durations of follow-up are required to confirm the results obtained.

Perioperative use of non-steroidal anti-inflammatory drugs might impair dental implant osseointegration

OBJECTIVE

To appraise whether adverse biological events following oral implant placement may be associated with perioperative use of non-steroidal anti-inflammatory drugs (NSAIDs).

METHODS

All patients treated in a university faculty postgraduate dental clinic between 1979 and 2012 that had experienced a failing and surgically removed dental implant (292 implants in 168 patients) were contacted to solicit additional information about their present dental and medical status and frequency of current and past use of NSAIDs. Potential associations between perioperative NSAIDs use and the occurrence of adverse biological events were explored by the use of 2 × 2 tables and two-tailed Fisher's exact tests.

RESULTS

One hundred and four patients with initially 468 implants had experienced 238 implant failures, of which 197 were due to failing osseointegration (42%). Sixty of the participants, initially with 273 implants, had used NSAIDs perioperatively and experienced 44% implant failures, versus 38% in the non-NSAID cohort. The NSAID cohort experienced 3.2 times more cases of radiographic bone loss greater than 30% of the vertical height of their remaining implants and 1.9 times more cases of cluster failures, defined as failure of 50% or more of the implant(s) placed.

CONCLUSIONS

Notwithstanding that a retrospective study design is open to potential bias, the current data indicate that dental implant osseointegration may be affected negatively by an inhibitory effect of NSAIDs on bone healing in vulnerable patients. Future and better clinical studies than the current should be designed to appraise more precisely the potential effects of NSAIDs on implant osseointegration in study populations that are not limited by stringent medical inclusion and exclusion criteria.

Indications and contraindications of dental implants in medically compromised patients: update

The aim of this study was to review the current scientific literature in order to analyse the indications and contraindications of dental implants in medically compromised patients. A reference research was carried out on PubMed using the key words “implant” AND (oral OR dental) AND (systemic disease OR medically compromised), in articles published between 1993 and 2013. The inclusion criteria were the following: clinical studies in which, at least, 10 patients were treated, consensus articles, reviewed articles and meta-analysis performed in humans treated with dental implants, and which included the disease diagnosis. A total of 64 articles were found, from which 16 met the inclusion criteria. Cardiac systemic diseases, diabetic endocrine pathologies or controlled metabolic disorders do not seem to be a total or partial contraindication to the placement of dental implants. Tobacco addiction, and head and neck radiotherapy are correlated to a higher loss of dental implants. Patients suffering from osteoporosis undergoing biphosphonates therapy show an increased risk of developing bone necrosis after an oral surgery, especially if the drugs are administered intravenously or they are associated to certain concomitant medication.

Key words:Dental implants, medically compromised patient, systemic diseases.

Effects of epigallocatechin-3-gallate on the healing of extraction sockets with a periapical lesion: A pilot study in dogs

The aim of this study was to characterize the healing process of extraction sockets with a periapical lesion following immediate graft with collagenated bovine bone mineral (CBBM) soaked with epigallocatechin-3-gallate (EGCG). Following induction of periapical lesions in premolars in five dogs, treatment of extraction sockets was divided into three groups: control (no treatment) and two test groups, CBBM with or without EGCG. 3D reconstruction and superimposition of the digital images were used to measure the dimensional changes in alveolar ridge. Histologic specimen was evaluated in all groups. The horizontal ridge widths at 4-mm level were wider in both test groups (3.3 ± 1.7 mm in CBBM; 3.0 ± 1.7 mm in CBBM+EGCG) than in the control group (1.7 ± 2.4 mm). Fibrosis and limited new bone formation were observed in the apical regions of test groups; however, the extent of fibrosis was less in the CBBM+EGCG group. Within the limitations of this study, it was conjectured that adjunctive use of EGCG with CBBM can be a candidate biomaterial in grafting of extraction socket with periapical lesion. Bone regeneration at the coronal region of the CBBM grafted socket might not be influenced by the presence of a periapical lesion.

Dental implant survival in diabetic patients; review and recommendations

Rising population of diabetic individuals across the world has become a big concern to the society. The persistent hyperglycemia may affect each and every tissue and consequently results in morbidity and eventually mortality in diabetic patients. A direct negative response of diabetes has been observed on oral tissues with few contradictions however, little are known about effect of diabetes on dental implant treatment and the consequent results. Many studies concerned with osteointegration and prognosis of dental implant in diabetic patients have been conducted and published since 1994. These studies have been critically reviewed to understand the impact of diabetes on the success of dental implant and the factors to improve osseointegration and consequently survival of dental implant in diabetic patients. Theoretical literatures and studies in diabetic animals substantiate high failure rate of implants but most of clinical studies indicated statistically insignificant failure of dental implants even in moderately uncontrolled diabetic patients. Success of dental implant in well and fairly controlled diabetic patients with proper treatment planning, prophylactic remedies and adequate postsurgical maintenance appears as good as normal individuals.

Effects of biomechanical properties of the bone-implant interface on dental implant stability: from in silico approaches to the patient's mouth

Dental implants have become a routinely used technique in dentistry for replacing teeth. However, risks of failure are still experienced and remain difficult to anticipate. Multiscale phenomena occurring around the implant interface determine the implant outcome. The aim of this review is to provide an understanding of the biomechanical behavior of the interface between a dental implant and the region of bone adjacent to it (the bone-implant interface) as a function of the interface's environment. First, we describe the determinants of implant stability in relation to the different multiscale simulation approaches used to model the evolution of the bone-implant interface. Then, we review the various aspects of osseointegration in relation to implant stability. Next, we describe the different approaches used in the literature to measure implant stability in vitro and in vivo. Last, we review various factors affecting the evolution of the bone-implant interface properties.

Peri-implant evaluation in type 2 diabetes mellitus patients: a 3-year study

OBJECTIVE

The aim of this study was to analyze the changes produced in peri-implant tissues in type 2 diabetes mellitus patients with different glycemia levels, measured by monitoring glycated hemoglobin A1c (HbA1c), over a period of 3 years following dental implant placement.

MATERIALS AND METHODS

Sixty-seven patients were divided into four groups according to their HbA1c levels: 21 patients in Group 1 (<6); 24 patients in Group 2 (6.1-8); and 11 patients in Group 3 (8.1-10) and Group 4 (>10.1). Each patient received one implant. All implants were placed in the anterior zone of the maxilla. The variables selected to assess the general state of patients' peri-implant health were as follows: probing depth, bleeding on probing, and marginal bone loss.

RESULTS

Marginal bone loss was found to increase in relation to increases in HbA1c levels. Bleeding on probing showed statistically significant differences between groups. When the peri-implant area was probed, mean levels of bleeding varied from 0.43 in Group 1 at 1 year after implant surgery to 0.62 in Group 4 (P = 0.042 between the four study groups). After the second year, greater bleeding on probing was observed in Group 4 (0.63) in comparison with groups with lower HbA1c levels. Peri-implant pocket depths presented values that were too low to be considered pathological and without statistically significant differences between the study groups.

CONCLUSION

Implant therapies for diabetic patients can be predictable, providing these patients fall within controlled ranges of glycemia over time, assessed by monitoring HbA1c levels.

Dental implant fractures - aetiology, treatment and case report

PURPOSE

This study aimed to investigate the etiology, clinical manifestations, and treatment options of dental implants fractures through a literature review and to relate a clinical report.

METHODS

A literature review was performed using the Medline database and this paper describes a case demonstrating the management of implant fracture. Twenty two articles were selected in the present literature review.

RESULTS

Nowadays the use of dental implants to rehabilitate completely and partially edentulous patients became the best treatment option; however, this treatment is suitable to failure. The fracture of implant body is a possible complication. The fracture of implant body is a late complication and is related to the failure in implant design or material, non-passive fitting of the prosthetic crown and overloading. Clinically, prosthesis instability and spontaneous bleeding are observed. Three options of treatment have been indicated: complete removal of implant fragment, maintenance of implant fragment, and surface preparation of the fragment with insertion of a new abutment.

CONCLUSION

The literature indicates the complete removal of the fragment as the best treatment option.

Production and repair of implant-induced microdamage in the cortical bone of goats after long-term estrogen deficiency

SUMMARY

By using an ovariectomized goat model, we found that estrogen depletion decreases bone quality and makes it susceptible to screw-induced mechanical microdamage. Both diffuse microdamage and linear cracks accumulated up to 3 weeks after screw implantation, and the microdamage was repaired gradually after 4-8 months.

INTRODUCTION

The aim of this study was to observe the effect of long-term estrogen deficiency on the creation and repair of microdamage in cortical bone adjacent to bone screw.

METHODS

Cortical bone screws were placed in the tibial diaphyses 28 months after ovariectomy (OVX) or sham operation (Sham-Op) in female goats. The goats were euthanized at 0 day, 21 days, 4 months, and 8 months after screw implantation. Microdamage morphology and repair were examined in peri-screw bone using histomorphometric method, and the nanomechanical properties of peri-screw bone were examined with nanoindentation testing.

RESULTS

Tibiae from ovariectomized goats in which screws had been placed had significantly higher levels of diffuse microdamage and significantly more linear cracks than those from sham goats, and the diffuse microdamage was more obvious than linear cracks in the region adjacent to the implant. Both diffuse microdamage and linear cracks accumulated up to day 21 and then gradually repaired at 4 and 8 months after surgery. The trend for bone remodeling in each group was consistent with changes in the level of microdamage. Nanoindentation testing showed that both elastic modulus and hardness in peri-screw bone were significantly decreased in OVX group compared to Sham-Op group. The hardness and elastic modulus also showed a downward trend up to 4 months after screw implantation and then exhibited some recovery after 8 months.

CONCLUSIONS

Estrogen depletion decreases bone quality and makes it vulnerable to screw-induced mechanical damage, which may compromise the initial stability of an orthopedic implant.

Hydroxyapatite and collagen combination-coated dental implants display better bone formation in the peri-implant area than the same combination plus bone morphogenetic protein-2-coated implants, hydroxyapatite only coated implants, and uncoated implants

PURPOSE

The objective of this study was to compare peri-implant bone formation among uncoated (UC), hydroxyapatite (HA), collagen plus HA (CH), and collagen, HA, plus bone morphogenetic protein-2 (BMP-2) implant groups.

MATERIALS AND METHODS

Implants in the UC group had acid-etched surfaces. The surface coating was applied using the aerosol deposition method. The coated surfaces were examined by scanning electron microscopy, x-ray diffraction (XRD), and Fourier-transformed infrared absorption analysis. Subsequently, 6 implants from each group (total, 24 implants) were installed in the tibias of rabbits. The animals were sacrificed at 6 weeks after implant installation. Peri-implant bone formation and bone-to-implant contact (BIC) were measured in histologic sections. Significant differences among groups were evaluated using analysis of variance.

RESULTS

Based on the measured XRD patterns, there was a characteristic HA phase (International Centre for Diffraction Data [ICDD], 086-0740) coated on the titanium (ICDD, 089-3725). Subsequent coating processes for collagen and BMP-2 did not display additional diffraction peaks, but maintained the diffraction patterns of the HA-coated titanium. The presence of collagen was verified by infrared absorption analysis. When comparing these modifications with UC surfaces, only the CH coating displayed significantly greater peri-implant bone formation and BIC (P = .003 and P < .001, respectively). Adding BMP-2 to the implant surface did not produce any advantage compared with the CH coating.

CONCLUSIONS

In this study, the CH group displayed significantly greater new bone formation and BIC than the other groups. There was no significant difference among the other groups.

Improved anchorage of Ti6Al4V orthopaedic bone implants through oligonucleotide mediated immobilization of BMP-2 in osteoporotic rats

The aim of the present study was to test the biocompatibility and functionality of orthopaedic bone implants with immobilized oligonucleotides serving as anchor stands for rhBMP-2 and rhVEGF-A conjugated with complementary oligonucleotides in an osteoporotic rat model. Al2O3-blasted acid etched Ti6Al4V implants, carrying oligonucleotide anchor strands and hybridized with rhBMP-2 or rhVEGF-A through complementary 31-mer oligonucleotide stands were inserted into the proximal tibia of ovariectomized rats. At the time of surgery (15 weeks after ovariectomy) microCT analysis showed significantly lower bone mineral density compared to non-ovariectomized animals. Bone-implant contact (BIC) and pullout-force were not negatively affected by non-hybridized anchor strands. Twelve weeks after surgery, a significantly higher pullout force was found for BMP-2 hybridized to the anchor strands compared to non-hybridized anchor strands or native samples, and on histomorphometric analysis BIC was highest in the BMP group. Thus, we could show the biocompatibility and in vivo functionality of this modular, self-organizing system for immobilization and subsequent release of BMP-2 in vivo.

An investigation of antibiotic prophylaxis in implant practice in the UK

BACKGROUND

There is increasing evidence of the inappropriate use of antimicrobials in dentistry and this may contribute to the problem of antimicrobial resistance. The research to date with regard to efficacy of antimicrobial prophylaxis in reducing failure of integration and postoperative complications when placing dental implants remains equivocal. The aim of this study was to investigate how dentists in the UK use antimicrobials prophylactically in implant practice.

METHOD

An e-mail link was provided in 2011 to an anonymous online (Smart-Survey) questionnaire using three databases of dentists who, by being on them, had registered an interest in placing dental implants. Absolute frequencies were used to describe the study sample demographics and examine the distribution of responses for all the variables investigated.

RESULTS

One hundred and nine completed questionnaires were received. Seventy-two percent (n = 76) routinely prescribed prophylactic antibiotics for all procedures. There was a wide variation in the pre-operative and postoperative prescription regimens with the majority (84%) stating that it was to prevent infection at the site of surgery or to reduce a bacteraemia.

CONCLUSIONS

Although this was a small study with a low response rate, wide variations in antibiotic prescribing regimens with respect to drug, dose and duration were found. Further research is needed and guidelines developed to prevent antibiotic overprescribing and misuse.

Rehabilitative considerations for dental implants in the diabetic patient

Diabetes is a serious illness that affects many people, and there are many new cases diagnosed every year in all populations around the world. Dental implant is one of the restorative methods to replace missing teeth. As implants are directly anchored into bones, they provide stability, a more natural appearance, and minimize the risk of bone resorption. Thus, today, there is a high demand of dental implants and it is inevitable to meet diabetics who request implant treatment. However, Diabetes mellitus patients may pose contraindications to dental implants because of microvascular complications leading to slower healing process after surgery. Studies have shown that dental implantation failure rate in diabetic patients is much higher than that in non-diabetic patients. This article reviews the effect of diabetes on the osseointegration of implants and the soft tissue healing. It presents the factors used in assessing the severity of diabetes and its complications, as well as considerations for rehabilitation planning in these patients. In addition, the role of antibiotic prophylaxis has been reviewed since its effect on wound healing in diabetics is controversial. Integration of these factors by the dentist can dictate whether, as well as what type of implant supported prosthesis should be given to the diabetic patient.

Immediate implants placed in fresh sockets associated to periapical infectious processes. A systematic review

Objetives: The development of treated implant surfaces, added to the increase of the aesthetic requirements by the patients has led to a change in the treatment protocols as well as the development of techniques such as the one-fase implants and the immediate prosthetic loading. One of the usual contraindications of the implant treatment is the presence of periapical disease associated to the tooth to be replaced. The aim of this paper is to review the published literature on immediate implant placement in extraction sockets of teeth with periapical pathology, considering the level of scientific evidence, and following the principles of medicine and evidence-based Dentistry. Material and Methods: A search of articles published between 1982 and 2012 was conducted. The search terms immediate, dental implant, extraction, infected, periapical pathology were used. Search was limited to studies in animals and humans, published in english language. Results: 16 articles were selected from a total of 438, which were stratified according to their level of scientific evidence using the SORT criteria (Strength of Recommendation Taxonomy). Studies in both animals and humans presented high rates of implant survival, but human studies are limited to a small number of cases. Discussion and Conclusions: There is a limited evidence regarding implant placement immediately to the extraction of teeth affected by chronic periapical pathology. Following analysis of the articles, and in function of their scientific quality, a type B recommendation is given in favor of the immediate implant placement in fresh sockets associated to periapical infectious processes.

Key words:Immediate implant, periapical pathology.

Chondroitin sulfate and sulfated hyaluronan-containing collagen coatings of titanium implants influence peri-implant bone formation in a minipig model

An improved osseous integration of dental implants in patients with lower bone quality is of particular interest. The aim of this study was to evaluate the effect of artificial extracellular matrix implant coatings on early bone formation. The coatings contained collagen (coll) in conjunction with either chondroitin sulfate (CS) or sulfated hyaluronan (sHya). Thirty-six screw-type, grit-blasted, and acid-etched titanium implants were inserted in the mandible of 6 minipigs. Three surface states were tested: (1) uncoated control (2) coll/CS (3) coll/sHya. After healing periods of 4 and 8 weeks, bone implant contact (BIC), bone volume density (BVD) as well as osteoid related parameters were measured. After 4 weeks, control implants showed a BIC of 44% which was comparable to coll/CS coated implants (48%) and significantly higher compared to coll/sHya coatings (37%, p = 0.012). This difference leveled out after 8 weeks. No significant differences could be detected for BVD values after 4 weeks and all surfaces showed reduced BVD values after 8 weeks. However, at that time, BVD around both, coll/CS (30%, p = 0.029), and coll/sHya (32%, p = 0.015), coatings was significantly higher compared to controls (22%). The osteoid implant contact (OIC) showed no significant differences after 4 weeks. After 8 weeks OIC for controls was comparable to coll/CS, the latter being significantly higher compared to coll/sHya (0.9% vs. 0.4%, p = 0.012). There were no significant differences in osteoid volume density. In summary, implant surface coatings by the chosen organic components of the extracellular matrix showed a certain potential to influence osseointegration in vivo.

Evaluation of implant success: A review of past and present concepts

Dental Implants have become the standard care of rehabilitation of missing teeth. This article intends to review the success criteria for implants from 1979 till date. Earlier days implant success was evaluated by immobility and peri-implant radiolucency. But currently, the width of the attached gingiva, co-existing medical conditions, smoking, and width of the implant also play a role in evaluating implant success. Genetic and immunological markers have also been identified.

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,(1) 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.

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.

Comparative molecular assessment of early osseointegration in implant-adherent cells

OBJECTIVE

The objective of our study is to identify the early molecular processes involved in osseointegration associated with a micro roughened and nanosurface superimposed featured implants.

MATERIALS AND METHODS

Thirty-two titanium implants with surface topographies exhibiting a micro roughened (AT-II) and nanosurface superimposed featured implants (AT-I) were placed in the tibiae of 8 rats and subsequently harvested at 2 and 4 days after placement. Total RNA was isolated from cells adherent to retrieved implants. A whole genome microarray using the Affymetrix Rat Gene 1.1 ST Array followed by validation of select genes through qRT-PCR was used to describe the gene expression profiles that were differentially regulated by the implant surfaces.

RESULTS

While significant differences at the gene level were not noted when comparing the two-implant surfaces at each time point, the microarray identified several genes that were differentially regulated at day 4 vs. day 2 for both implant surfaces. A total of 649 genes were differentially regulated at day 4 vs. day 2 in AT-I and 392 genes in AT-II implants. Functionally relevant categories related to ossification, skeletal system development, osteoblast differentiation, bone development, bone mineralization and biomineral tissue development were upregulated and more prominent at AT-I (day 4 vs. day 2) compared to AT-II. Analysis of the downregulated gene lists (day 4 vs. day 2) with average fold change >2 (were not statistically significant) revealed the biological processes involved with the inflammatory/immune response gene expression. The number of genes that were associated with the inflammatory/immune response category was greater for AT-I than AT-II.

CONCLUSIONS

The presence of nanosurface features modulated in vivo bone response. Gene regulation implicating osteogenesis as well as the inflammatory/immune responses that occur as a function of surface topography may affect bone mass shortly after implant placement.

Success of miniscrews used as anchorage for orthodontic treatment: analysis of different factors

OBJECTIVES

To examine factors involved in clinical success of miniscrew implants used for orthodontic anchorage in the upper jaw.

MATERIALS AND METHODS

One hundred and forty-four patients (93 females and 51 males) were fitted with a total of 324 miniscrew implants of two different morphologies (cylindrical and conical), and of different lengths and diameters. The clinical factors examined were screw length, side of insertion, miniscrew shape and diameter, bone quality, skeletal type, and relationship between bone quality and skeletal type and patient age.

RESULTS

The mean overall success rate of the implants was 91.4%. The length and shape of the miniscrews significantly influenced the success rate, whereas side of insertion (left or right), screw diameter and skeletal type showed no significant effects. Poor (soft) bone quality and good (hard) bone quality are risk factors for miniscrew failure, with the best results obtained when the screws are inserted into bone of medium quality (10-15Ncm).

CONCLUSION

In the posterior areas of the upper jaw, long, conical miniscrews showed a significantly greater success rate. An insertion torque of 10 Ncm to 15 Ncm is also a significant index of higher success rate.

Bone healing around titanium implants in two rat colitis models

OBJECTIVE

Crohn's disease is a chronic inflammatory process that has recently been associated with a higher risk of early implant failure. Herein we provide information on the impact of colitis on peri-implant bone formation using preclinical models of chemically induced colitis.

METHODS

Colitis was induced by intrarectal instillation of 2,4,6-trinitro-benzene-sulfonic-acid (TNBS). Colitis was also induced by feeding rats dextran-sodium-sulfate (DSS) in drinking water. One week after disease induction, titanium miniscrews were inserted into the tibia. Four weeks after implantation, peri-implant bone volume per tissue volume (BV/TV) and bone-to-implant contacts (BIC) were determined by histomorphometric analysis.

RESULTS

Cortical histomorphometric parameters were similar in the control (n = 10), DSS (n = 10) and TNBS (n = 8) groups. Cortical BV/TV was 92.2 ± 3.7%, 92.0 ± 3.0% and 92.6 ± 2.7%. Cortical BIC was 81.3 ± 8.8%, 83.2 ± 8.4% and 84.0 ± 7.0%, respectively. No significant differences were observed when comparing the medullary BV/TV and BIC (19.5 ± 6.4%, 16.2 ± 5.6% and 15.4 ± 9.0%) and (48.8 ± 12.9%, 49.2 ± 6.2 and 41.9 ± 11.7%), respectively. Successful induction of colitis was confirmed by loss of body weight and colon morphology.

CONCLUSIONS

The results suggest bone regeneration around implants is not impaired in chemically induced colitis models. Considering that Crohn's disease can affect any part of the gastrointestinal tract including the mouth, our model only partially reflects the clinical situation.

Patient-related risk factors for implant therapy. A critique of pertinent literature

BACKGROUND

Treatment planning for dental implants involves the assessment of patient-related risk factors prior to formulation of a treatment plan. The aim of this review was to assess relevant literature and provide evidence-based information on the successful surgical placement of dental implants.

METHODS

An electronic search of Medline, PubMed and the Cochrane Databases of Systematic Reviews was undertaken using a combination of MeSH terms and keywords. A handsearch was also performed and cross-referenced with articles cited in papers selected. The primary study parameter was implant failure.

RESULTS

Forty-three studies were selected based on specific inclusion criteria. Many studies contain confounding variables, numbers in subcategories are often too small for meaningful statistical analysis, and follow-up times vary and are often short-term.

CONCLUSIONS

There are many risk factors which the clinician is required to know and understand to advise patients, and consider in planning and treatment provision. Consistent evidence exists to show an increased failure rate with smokers, a history of radiotherapy and local bone quality and quantity. Weaker evidence exists to show a higher incidence of peri-implant disease in patients with a history of periodontitis-related tooth loss. Lack of evidence precludes definitive guidelines for patients with autoimmune disorders where expert opinion recommends caution. Osteoporotic patients show acceptable survival rates; however patients on oral bisphosphonates show a small incidence but high morbidity from osteonecrosis of the jaw. Emerging evidence suggests that there is a correlation between genetic traits and disruption of osseointegration.