Microbiologically compromised patients and impact on oral implants

A retrospective study of the long-term survival of RESTORE® dental implants with resorbable blast media surface

PURPOSE

The aim of this study was to retrospectively evaluate the survival and failure rates of RESTORE® implants over a follow-up period of 10-15 years at a university dental hospital and to investigate the factors affecting the survival rate of these dental implants.

METHODS

A total of 247 RESTORE® dental implants with a resorbable blast media (RBM) surface inserted in 86 patients between March 2006 and April 2011 at the Department of Periodontology of Seoul National University Dental Hospital were included. Patients with follow-up periods of less than 10 years were excluded, and data analysis was conducted based on dental records and radiographs.

RESULTS

Over a 10- to 15-year period, the cumulative survival rate of the implants was 92.5%. Seventeen implants (6.88%) were explanted due to implant fracture (n=10, 4.05%), peri-implantitis (n=6, 2.43%), and screw fracture (n=1, 0.4%). The results of univariate regression analysis using a Cox proportional hazards model demonstrated that implants placed in male patients (hazard ratio [HR], 4.542; 95% confidence interval [CI], 1.305-15.807; P=0.017) and implants that supported removable prostheses (HR, 15.498; 95% CI, 3.105-77.357; P=0.001) showed statistically significant associations with implant failure.

CONCLUSIONS

Within the limitations of this retrospective study, the RESTORE® dental implant with an RBM surface has a favorable survival rate with stable clinical outcomes.

Effects of adjacent periodontitis on osseointegrated dental implants

PURPOSE

This study aimed to investigate whether new-onset periodontitis or apical periodontitis in the adjacent teeth affects osseointegrated dental implants in a beagle dog model.

METHODS

One control group and 2 experimental groups (periodontitis and apical periodontitis groups) were defined based on the presence of experimental periodontitis or apical periodontitis, with 1 beagle dog randomly assigned to each group. The mandibular second and fourth premolars on both sides of the 3 beagles were extracted. Eight weeks after extraction, 4 bone-level implant fixtures, 2 on both sides of each mandible, were placed in each beagle. Six weeks after implant surgery, healing abutments were connected. After sufficient osseointegration, plaque control was performed in the control group, while periodontitis and apical periodontitis were induced in the experimental groups. The beagles were euthanized for histological analyses 20 weeks after induction of experimental periodontitis. Statistical analyses were performed using the Kruskal-Wallis test with the Bonferroni correction to compare the 3 groups.

RESULTS

The implants in the control and apical periodontitis groups were well-maintained, while those in the periodontitis group showed clinical signs of inflammation with bone resorption. The bone-to-implant contact (BIC) and bone area values in the periodontitis group were lower than those in the other groups. The distance between the implant shoulder and the first BIC was significantly greater in the periodontitis group than in the control group (P<0.05).

CONCLUSIONS

The presence of periodontitis in adjacent teeth can pose a risk to dental implants, potentially resulting in peri-implantitis. However, this was not observed for apical periodontitis. Within the limitations of this study, periodontal care is necessary to reduce the impact of periodontitis in adjacent teeth on osseointegrated implants.

Complications in implant dentistry

After tooth loss, an individual may seek tooth replacement so that his/her function and esthetics could be restored. Clinical prosthodontics, during the past decade, has significantly improved and developed according to the advancements in the science and patient's demands and needs. Conventional options in prosthodontics for substituting a missing single tooth include the removable partial denture, partial and full coverage bridgework, and resin-bonded bridgework. Dental implants have gained increasing popularity over the years as they are capable of restoring the function to near normal in both partial and completely edentulous arches. With substantial evidence available, fixed implant-supported prosthesis are fully acknowledged as a reliable treatment option for the replacement of single or multiple missing teeth nowadays. While dental implants are increasingly becoming the choice of replacement for missing teeth, the impediments associated with them are progressively emerging too.

Effect of dental implant surface roughness in patients with a history of periodontal disease: a systematic review and meta-analysis

BACKGROUND

To review the literature on the effect of dental implant surface roughness in patients with a history of periodontal disease. The present review addresses the following focus question: Is there a difference for implant survival, mean marginal bone loss, and the incidence of bleeding on probing in periodontally compromised patients receiving a machined dental implant or rough surface dental implant?

METHODS

Electronic and manual literature searches were conducted on PubMed/MEDLINE and the Cochrane Library on studies published until May 2018 to collect information about the effect of machined, moderately rough, and rough dental implant surfaces in patients with a history of periodontal disease. The outcome variables implant survival, mean marginal bone level, and the incidence of peri-implantitis and bleeding on probing were evaluated. Meta-analysis was performed to obtain an accurate estimation of the overall, cumulative results.

RESULTS

Out of 2411 articles, six studies were included in this systematic review. The meta-analysis of the implant survival and implant mean marginal bone loss revealed a risk ratio of 2.92 (CI 95% 0.45, 18.86) for implant failure and a total mean difference of - 0.09 (CI 95% - 0.31, 0.14) for implant mean marginal bone loss measured in a total group of 215 implants, both not statistically significant.

CONCLUSIONS

Due to lack of long-term data (> 5 years), the heterogeneity and variability in study designs and lack of reporting on confounding factors, definitive conclusions on differences in implant survival, and mean marginal bone loss between machined and moderate rough implants in periodontally compromised patients cannot be drawn. Future well-designed long-term randomized controlled trials are necessary to reveal that machined surfaces are superior to moderately rough and rough surfaces in patients with a history of periodontal disease.

Soft Lithography and Minimally Human Invasive Technique for Rapid Screening of Oral Biofilm Formation on New Microfabricated Dental Material Surfaces

Introduction

Microfabrication offers opportunities to study surface concepts focused to reduce bacterial adhesion on implants using human minimally invasive rapid screening (hMIRS). Wide information is available about cell/biomaterial interactions using eukaryotic and prokaryotic cells on surfaces of dental materials with different topographies, but studies using human being are still limited.

Objective

To evaluate a synergy of microfabrication and hMIRS to study the bacterial adhesion on micropatterned surfaces for dental materials.

Materials and Methods

Micropatterned and flat surfaces on biomedical PDMS disks were produced by soft lithography. The hMIRS approach was used to evaluate the total oral bacterial adhesion on PDMS surfaces placed in the oral cavity of five volunteers (the study was approved by the University Ethical Committee). After 24 h, the disks were analyzed using MTT assay and light microscopy.

Results

In the present pilot study, microwell structures were microfabricated on the PDMS surface via soft lithography with a spacing of 5 µm. Overall, bacterial adhesion did not significantly differ between the flat and micropatterned surfaces. However, individual analysis of two subjects showed greater bacterial adhesion on the micropatterned surfaces than on the flat surfaces.

Significance

Microfabrication and hMIRS might be implemented to study the cell/biomaterial interactions for dental materials.

In vivo evaluation of an antibacterial coating containing halogenated furanone compound-loaded poly(l-lactic acid) nanoparticles on microarc-oxidized titanium implants

To prevent peri-implant infection, a new antibacterial coating containing a halogenated furanone compound, (Z-)-4-bromo-5-(bromomethylene)-2(5H)-furanone-loaded poly(l-lactic acid) nanoparticles, has been fabricated. The current study was designed to evaluate the preventive effect of the antibacterial coating under a simulated environment of peri-implant infection in vivo. Microarc-oxidized titanium implants treated with minocycline hydrochloride ointment were used as positive control group, and microarc-oxidized titanium implants without any treatment were used as blank control group. Three kinds of implants were implanted in dogs’ mandibles, and the peri-implant infection was simulated by silk ligation and feeding high sugar diet. After 2-month implantation, the results showed that no significant differences were detected between the experimental and positive control groups (P>0.05), but the data of clinical measurements of the blank control group were significantly higher than those of the other two groups (P<0.05), and the bone–implant contact rate and ultimate interfacial strength were significantly lower than those of the other two groups (P<0.05). Scanning electron microscope observation and histological examination showed that more new bone was formed on the surface of the experimental and positive control groups. It can be concluded that the antibacterial coating fabricated on implants has remarkable preventive effect on peri-implant infection at the early stage.

Inhibition of initial bacterial adhesion on titanium surfaces by lactoferrin coating

Because dental implant abutments are located at transmucosal sites, their surface should inhibit bacterial accumulation to prevent peri-implantitis. The authors examined the effects of human lactoferrin (LF), an antibacterial protein present in saliva, as an antibacterial coating on the titanium surface and evaluated its effects before and after mucin-containing artificial saliva (AS) incubation. In the control group, titanium disks were soaked in distilled water, whereas in the LF group, titanium disks were soaked in LF solution to coat the disks. In the control-AS and LF-AS groups, half of the control and LF disks were incubated with AS. To confirm LF adsorption, the fluorescence intensity of fluorescein isothiocyanate-labeled LF was measured. The LF and LF-AS groups showed significantly higher intensity than the control and control-AS groups (P < 0.01). There was no significant difference between the LF and LF-AS groups (P > 0.05). The amount of adhered Streptococcus gordonii significantly increased by incubation with AS (P < 0.01) and significantly decreased by adsorption of LF (P < 0.01). There was no interaction between the two factors, LF adsorption and AS incubation (P = 0.561). These results suggest that the adsorbed LF inhibited bacterial adhesion following AS incubation. According to qualitative LIVE/DEAD analysis, viable bacteria appeared to be decreased in the presence of LF and SEM observation indicated that altered morphologies increased in LF and LF-AS groups. These results suggest that the adsorbed LF remained on the titanium surface after incubation with AS, and the remaining LF inhibited bacterial adhesion and exhibited bactericidal effects. Therefore, the adsorption of LF on the abutment material appears to be effective in preventing peri-implantitis.

Fabrication and in vitro release behavior of a novel antibacterial coating containing halogenated furanone-loaded poly(L-lactic acid) nanoparticles on microarc-oxidized titanium

Background

Dental implants have become increasingly common for the management of missing teeth. However, peri-implant infection remains a problem, is usually difficult to treat, and may lead eventually to dental implant failure. The aim of this study was to fabricate a novel antibacterial coating containing a halogenated furanone compound, ie, (Z-)-4-bromo-5-(bromomethylene)-2(5H)-furanone (BBF)-loaded poly(L-lactic acid) (PLLA) nanoparticles on microarc-oxidized titanium and to evaluate its release behavior in vitro.

Methods

BBF-loaded PLLA nanoparticles were prepared using the emulsion solvent-evaporation method, and the antibacterial coating was fabricated by cross-linking BBF-loaded PLLA nanoparticles with gelatin on microarc-oxidized titanium.

Results

The BBF-loaded PLLA nanoparticles had a small particle size (408 ± 14 nm), a low polydispersity index (0.140 ± 0.008), a high encapsulation efficiency (72.44% ± 1.27%), and a fine spherical shape with a smooth surface. The morphology of the fabricated antibacterial coating showed that the BBF-loaded PLLA nanoparticles were well distributed in the pores of the microarc oxidation coating, and were cross-linked with each other and the wall pores by gelatin. The release study indicated that the antibacterial coating could achieve sustained release of BBF for 60 days, with a slight initial burst release during the first 4 hours.

Conclusion

The novel antibacterial coating fabricated in this study is a potentially promising method for prevention of early peri-implant infection.

Oral rehabilitation considerations for partially edentulous periodontal patients

Traditional tooth-supported and implant-supported fixed/removable restorations are currently used to replace teeth lost due to periodontal disease. This article reviews the existing literature for oral rehabilitation of partially edentulous periodontal patients with various designs of removable dental prosthesis (RDP), fixed dental prosthesis (FDP) and implant-supported single crown (SC), by addressing their (a) general features, (b) survival and complication rates, along with considerations for treatment planning in periodontal patients, and (c) preference by patients. To answer these issues, relevant articles were searched and critically analyzed, and their data were extracted. Data reviewed indicated that despite many advantages, implant-supported restorations have higher complication rates than tooth-supported restorations. Systematic reviews on conventional RDPs are lacking, but existing literature reviews provide limited evidence suggesting the use of RDPs with design modifications along with strict periodontal care in periodontal patients. Numerous systematic reviews on conventional FDPs and implant-supported restorations provide a moderate level of evidence favoring their survival in periodontal patients; however, for long-term success of these restorations, the patient's periodontal condition needs to be stabilized. In terms of patient preference, no restoration is superior, as they all are governed by their cost, advantages, and disadvantages. Thus, in the wake of existing weak evidence for prosthodontic rehabilitation of periodontal patients by these restorations (especially, conventional RDPs and for FDPs and SCs in implant-supported restorations), longitudinal studies with standardized treatment protocol and methodology are needed to evaluate and compare tooth-supported and implant-supported restorations in periodontal patients with regard to survival rates, cost, maintenance, and patient-centered outcomes.

Effect of air polishing with glycine powder on titanium abutment surfaces

OBJECTIVE

The aim of the present study was to evaluate morphological changes induced by glycine powder air polishing on titanium surfaces and its effect on bacteria recolonization in comparison with sodium bicarbonate powder.

MATERIALS AND METHODS

5 mm wide and 1 mm thick titanium grade II disks were divided into three groups of treatments: (i) no treatment; (ii) air polishing with glycine powder; (iii) air polishing with sodium bicarbonate powder. Specimens were characterized by laser profilometry, scanning electron microscopy (SEM) and then installed onto removable appliances worn for 24 h by healthy volunteers. Surface contamination was evaluated using SEM and counting the number of colony forming units (CFU).

RESULTS

SEM observation revealed an increased roughness with the formation of craters on samples treated with sodium bicarbonate powder, while not in glycine ones. Statistical analysis failed to show significant differences of both Ra and Rmax parameters in treated groups. SEM observation of specimens surfaces, after 24 h of permanence in the oral cavity, showed a higher contamination of the disks treated with sodium bicarbonate compared with those not treated (P < 0.05). Conversely, the group treated with glycine showed the lower contamination if compared with bicarbonate-treated group (P < 0.05).

CONCLUSIONS

Air polishing with glycine powder may be considered as a better method to remove plaque from dental implant because glycine is less aggressive than sodium bicarbonate powder. Moreover, the use of glycine powder seems to have an active role on the inhibition of bacterial recolonization of implants in a short test period (24 h). Further studies are needed to demonstrate the bacteriostatic properties of glycine, envisaged on the basis of reduced contamination of the disks polished with glycine compared with those not treated.

Biomaterial and antibiotic strategies for peri-implantitis: a review

Dental implants have 89% plus survival rates at 10-15 years, but peri-implantitis or dental implant infections may be as high as 14%. Peri-implantitis can limit clinical success and impose health and financial burdens to patients and health providers. The pathogenic species associated with periodontitis (e.g., Fusobacterium ssp, A. actinomycetemcomitans, P. gingivalis) are also associated with peri-implantitis. Incidence of peri-implantitis is highest within the first 12 months after implantation, and is higher in patients who smoke or have poor oral health as well as with calcium-phosphate-coated or surface-roughened implants. Biomaterial therapies using fibers, gels, and beads to deliver antibiotics have been used in the treatment of Peri-implantitis though clinical efficacy is not well documented. Guided tissue regeneration membranes (e.g., collagen, poly-lactic/glycolic acid, chitosan, ePTFE) loaded with antimicrobials have shown success in reosseointegrating infected implants in animal models but have not been proven in humans. Experimental approaches include the development of anti-bioadhesion coatings, coating surfaces with antimicrobial agents (e.g., vancomycin, Ag, Zn) or antimicrobial releasing coatings (e.g., calcium phosphate, polylactic acid, chitosan). Future strategies include the development of surfaces that become antibacterial in response to infection, and improvements in the permucosal seal. Research is still needed to identify strategies to prevent bacterial attachment and enhance normal cell/tissue attachment to implant surfaces.

Impact of supportive periodontal therapy and implant surface roughness on implant outcome in patients with a history of periodontitis

OBJECTIVE

This review searched for a relationship between susceptibility to periodontitis and peri-implantitis, with implant outcome as the primary outcome variable and supportive periodontal therapy (SPT) and implant surface roughness as confounding factors.

MATERIAL AND METHODS

It is based on a MEDLINE search up to June 2006. Only 16 fulfilled the selection criteria. The heterogeneity of the studies (e.g. periodontal status, SPT, prosthetic design, ...) rendered a meta-analysis impossible. The impact of a history of periodontitis on early implant loss was negligible. Only five papers reported sub-data for patients with different degrees of periodontitis. Four out of five papers indicate a higher incidence of late implant loss and/or marginal bone loss in patients with a history of periodontitis. This difference was most obvious for very rough implants (three papers), and/or when SPT was not organized (one paper). Other confounding factors were often neglected. Another 10 papers only reported the outcome of implants in patients with a history of periodontitis. In case of SPT and when avoiding roughened surfaces, late implant loss remained below 3%, and marginal bone loss remained low.

CONCLUSIONS

These results seem to indicate that periodontally compromised patients can be successfully treated with minimally/moderately rough implants, in the presence of SPT.

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

AIM

The aim of this retrospective study was to assess the influence of systemic and local bone and intra-oral factors on the occurrence of early implant failures, i.e. up to the abutment connection.

MATERIAL AND METHODS

The surgical records of 2004 consecutive patients from the total patient population who had been treated in the period 1982-2003 (with a total of 6946 Brånemark system implants) at the Department of Periodontology of the Catholic University Leuven were evaluated. For each patient the medical history was carefully checked. Data collection and analysis mainly focused on endogenous factors such as hypertension, coagulation problems, osteoporosis, hypo-hyperthyroidy, chemotherapy, diabetes type I or II, Crohn's disease, some local factors [e.g. bone quality and quantity, implant (length, diameter, location), type of edentulism, Periotest value at implant insertion, radiotherapy], smoking habits and breach of sterility during surgery.

RESULTS

A global failure rate of 3.6% was recorded. Osteoporosis, Crohn's disease, smoking habits, implant (length, diameter and location) and vicinity with the natural dentition were all significantly associated with early implant failures (p<0.05).

CONCLUSION

The indication for the use of oral implants should sometimes be reconsidered when alternative prosthetic treatments are available in the presence of possibly interfering systemic or local factors.

Dynamics of initial subgingival colonization of ‘pristine’ peri-implant pockets

BACKGROUND

Periodontitis and peri-implantitis are linked to the presence of several key pathogens. The treatment of these infectious processes therefore involves the reduction/eradication of bacteria associated with periodontitis.

METHODS

This prospective, split-mouth, single-blind study followed the colonization of 'pristine' sulci created in 42 partially edentulous patients during implant surgery (e.g. abutment connection). The hypothesis was that the composition of the maturing subgingival plaque in these 'fresh' peri-implant pockets would soon (within 2 weeks) be comparable to the subgingival microbiota of teeth with similar clinical parameters (reference sites), including the presence of bacteria associated with periodontitis. Per patient, four subgingival plaque samples were taken from shallow and medium pockets around implants (test sites), and teeth within the same quadrant (undisturbed microbiota as control sites), 1, 2, 4, 13, 26 and 78 weeks after abutment connection, respectively. The samples were analysed by either checkerboard DNA-DNA hybridization, or cultural techniques, or real-time polymerase chain reaction (PCR) for intra-subject comparisons (teeth vs. implant, for comparable probing depths).

RESULTS

Checkerboard DNA-DNA hybridization and real-time PCR revealed a complex microbiota (including several pathogenic species) in the peri-implant pockets within 2 weeks after abutment connection. After 7 days, the detection frequency for most species (including the bacteria associated with periodontitis) was already nearly identical in samples from the fresh peri-implant pockets (5% and 20% of the microbiota belonging to red and orange complex, respectively) when compared with samples from the reference teeth. Afterwards (e.g. between weeks 2 and 13), the number of bacteria in peri-implant pockets only slightly increased (+/-0.1 log value), with minor changes in the relative proportions of bacteria associated with periodontitis (8% and 33% of the microbiota belonging to red and orange complex, respectively). Although small differences were seen between teeth and implants at week 2 with cultural techniques, a striking similarity in subgingival microbiota was found with this technique from month 3 on, with nearly identical detection frequencies for bacteria associated with periodontitis for both abutment types.

CONCLUSIONS

This study indicates that the initial colonization of peri-implant pockets with bacteria associated with periodontitis occurs within 2 weeks.