Frequency of peri-implant diseases and associated factors

Enhancing Bone Implants: Magnesium-Doped Hydroxyapatite for Stronger, Bioactive, and Biocompatible Applications

Hydroxyapatite (HAp) with the chemical formula Ca10(PO4)6(OH)2 is an inorganic material that exhibits morphology and composition similar to those of human bone tissues, making it highly desirable for bone regeneration applications. As one of the most biocompatible materials currently in use, HAp has undergone numerous attempts to enhance its mechanical strength. This research focuses on investigating the influence of magnesium (Mg) incorporation on the structural and mechanical properties of synthesized magnesium-doped hydroxyapatite (MgHAp) samples. Apart from its biocompatibility, Mg possesses a density and elasticity comparable to those of human bone. Therefore, incorporating Mg into HAp can be pivotal for improving bone formation. Previous studies have not extensively explored the structural changes induced by Mg substitution in HAp, which motivated us to revisit this issue. Hydrothermal synthesis technique was used to synthesize MgHAp samples with varying molar concentrations (x = 0, 0.5, 1.0, and 1.5). Theoretical simulation of HAp and MgHAp for obtaining 3D structures has been done, and theoretical X-ray diffraction (XRD) data have been compared with the experimental XRD data. Rietveld analysis revealed the alteration and deviation of lattice parameters with an increase in the Mg content, which ultimately affect the structure as well the mechanical properties of prepared samples. The findings revealed an increase in compressive stress and fracture toughness as the Mg concentration in the composition increased. Furthermore, using a finite-element analysis technique and modeling of the mechanical testing data, the von Mises stress distribution and Young's modulus values were calculated, demonstrating the similarity of the prepared samples to human cortical bone. Biocompatibility assessments using NIH-3T3 fibroblast cells confirmed the biocompatible and bioactive nature of the synthesized samples. MgHAp exhibits great potential for biomedical applications in the dental, orthopedic, and tissue engineering research fields.

Treatment of peri-implant mucositis: Adjunctive effect of glycine powder air polishing to professional mechanical biofilm removal. 12 months randomized clinical study

INTRODUCTION

To evaluate the adjunctive effect of glycine-powder air-polishing (GPAP) to full-mouth ultrasonic debridement (Fm-UD) in the treatment of peri-implant mucositis, and to determine the impact of implant and patient-level variables for disease resolution.

METHODS

Individuals with a diagnosis of peri-implant mucositis were consecutively included in this randomized parallel arm clinical study. All the participants received a session of Fm-UD. Only implants allocated to the test group were additionally treated with GPAP. Clinical assessments were recorded at baseline, at 3 and at 12 months following intervention. The primary outcomes were complete disease resolution (DR1), defined as absence of bleeding sites at probing per implants, and partial disease resolution (DR2), measured as the presence of less than two bleeding sites at probing per implant. A final logistic multivariate regression model was built to evaluate the predictive role of implant and patient-level variables on DR.

RESULTS

Fifty two patients and 157 implants were included. Both groups displayed significant reduction in the extent of bleeding on probing and plaque levels. At 12 months, DR1 was achieved in 16% and 27% of participants for the test and the control group respectively. IDR1 was best predicted by the number of bleeding sites (OR = 2.7, p = 0.04) and the greatest PPD value (OR = 2.7, p = 0.05), while IDR2 by the prosthetic connection (OR = 2.59, p = 0.02), the mean PPD (OR = 2.23, p = 0.04), the FMBS (OR = 4.09, p = 0.04), and number of implants (OR = 4.59, p = 0.02).

CONCLUSIONS

Despite significant improvements of clinical signs of peri-implant inflammation, the use of GPAP appears to have no adjunctive effect as compared with Fm-UD alone in the achievement of DR. Elevated initial levels of bleeding and PD predicted inferior likelihood of reaching disease resolution. The present randomized parallel arm clinical study was registered on Clinicaltrials.gov and received the following registration number: NCT05801315. This clinical trial was not registered prior to participant recruitment and randomization (https://register.

CLINICALTRIALS

gov/prs/app/action/SelectProtocol?sid=S0009965&selectaction=Edit&uid=U0004FXM&ts=2&cx=fje7l8).

Clinical, Bacterial, and Prosthodontic Parameters After Implant Abutment Disinfection Using Nd:YAG, Er,Cr:YSGG, Chlorhexidine, and Conventional Steam Before Prosthesis Delivery

Objective: This 1-year prospective clinical trial was designed to assess the microbial, clinical, radiographic, and prosthetic parameters after disinfection of the implant abutment connection using Er,Cr:YSGG (erbium, chromium-doped: yttrium, scandium, gallium, and garnet) and Nd:YAG (neodymium-doped yttrium, aluminum, garnet). Materials and methods: All the patients were divided into four groups; Group I: Nd:YAG laser, Group II: Er,Cr:YSGG laser, Group III: 0.2% chlorhexidine (CHx), and Group IV: steam disinfection. Peri-implant parameters assessed included peri-implant bleeding scores (PIBS), peri-implant plaque scores (PIPS), peri-implant pocket depth (PIPD), and crestal bone loss (CBL). The peri-implant plaque samples were acquired to perform microbiological analysis to assess Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia, respectively. All measurements were completed at baseline, 6 months, and 12 months postsurgery. Multiple groups were compared with the help of the Bonferroni post-hoc adjustment test (p < 0.01). Logistic regression models were utilized to assess the association between age, oral hygiene practices (brushing and flossing), and duration of implant function. Results: At the baseline level, there were no discernible differences in the peri-implant parameters between the study groups (p > 0.05). At the 6-month (p < 0.01) and 12-month (p < 0.001) follow-ups, all four study groups demonstrated a significant improvement in PIPS and PIBS, with no significant differences between the groups at baseline (p > 0.05). Based on an intergroup comparison, Group I (Nd:YAG) showed a significant decrease in PIBS when compared with the other groups. Group II showed a considerable decrease in PIPD and enhancements in CBL when compared with Groups I, III, and IV (p < 0.01). At the 6- and 12-month follow-up periods, P. gingivalis and T. denticola reduction were found to be statistically higher in Group II, whereas P. gingivalis and T. forsythia mean log CFU/mL were found to be statistically higher in Group I. Conclusions: Nd:YAG and Er,Cr:YSGG lasers both outperformed CHx and steam disinfection in terms of clinical, peri-implant, and prosthetic results when used to clean implant abutments.

Influence of Periodontal Status and Prosthetic Treatment on Survival and Success Rates in Implant Therapy: A 5-Year Retrospective Follow-Up Study

The objective of the present study was to evaluate the 5-year outcome of dental implant therapy and assess the survival, success, and biological and technical complications. A periodontal and prosthetic-oriented evaluation was conducted on the variables that can influence the long-term predictability of implant therapy. A total of 615 patients and 1427 dental implants from a private clinic (MedArtis Dent, Cluj-Napoca, Romania) were enrolled in the study. The study was a longitudinal cohort with data collected retrospectively from physical/digital dental records in combination with a cross-sectional clinical/radiological examination. Results showed that periodontal diagnosis at baseline had a significant impact on the marginal bone loss prediction. Data showed that the cylindrical implant with an internal 45° medium taper connection experienced a higher rate of bone resorption compared to the tapered implant with the 5° internal connection. Screw-retained restorations and overdentures showed a statistical decrease in the marginal bone level height when compared to the cemented restorations. Data from our study suggest that not only is there a powerful association between recall visits and the rate of complications in dental implant treatment, but a lack of professional maintenance predicts a higher bone level loss during the 5-year interval.

Primordial and primary prevention of peri-implant diseases: A systematic review and meta-analysis

AIM

This systematic review and meta-analysis aims to assess the efficacy of risk factor control to prevent the occurrence of peri-implant diseases (PIDs) in adult patients awaiting dental implant rehabilitation (primordial prevention) or in patients with dental implants surrounded by healthy peri-implant tissues (primary prevention).

MATERIALS AND METHODS

A literature search was performed without any time limit on different databases up to August 2022. Interventional and observational studies with at least 6 months of follow-up were considered. The occurrence of peri-implant mucositis and/or peri-implantitis was the primary outcome. Pooled data analyses were performed using random effect models according to the type of risk factor and outcome.

RESULTS

Overall, 48 studies were selected. None assessed the efficacy of primordial preventive interventions for PIDs. Indirect evidence on the primary prevention of PID indicated that diabetic patients with dental implants and good glycaemic control have a significantly lower risk of peri-implantitis (odds ratio [OR] = 0.16; 95% confidence interval [CI]: 0.03-0.96; I² : 0%), and lower marginal bone level (MBL) changes (OR = -0.36 mm; 95% CI: -0.65 to -0.07; I² : 95%) compared to diabetic patients with poor glycaemic control. Patients attending supportive periodontal/peri-implant care (SPC) regularly have a lower risk of overall PIDs (OR = 0.42; 95% CI: 0.24-0.75; I² : 57%) and peri-implantitis compared to irregular attendees. The risk of dental implant failure (OR = 3.76; 95% CI: 1.50-9.45; I² : 0%) appears to be greater under irregular or no SPC than regular SPC. Implants sites with augmented peri-implant keratinized mucosa (PIKM) show lower peri-implant inflammation (SMD = -1.18; 95% CI: -1.85 to -0.51; I² : 69%) and lower MBL changes (MD = -0.25; 95% CI: -0.45 to -0.05; I² : 62%) compared to dental implants with PIKM deficiency. Studies on smoking cessation and oral hygiene behaviors were inconclusive.

CONCLUSIONS

Within the limitations of available evidence, the present findings indicate that in patients with diabetes, glycaemic control should be promoted to avoid peri-implantitis development. The primary prevention of peri-implantitis should involve regular SPC. PIKM augmentation procedures, where a PIKM deficiency exists, may favour the control of peri-implant inflammation and the stability of MBL. Further studies are needed to assess the impact of smoking cessation and oral hygiene behaviours, as well as the implementation of standardized primordial and primary prevention protocols for PIDs.

Long‐term impact of patients' compliance to peri‐implant maintenance therapy on the incidence of peri‐implant diseases: An 11‐year prospective follow‐up clinical study

OBJECTIVE

To prospectively evaluate the incidence of peri-implant diseases and the associated risk factors during 11 years of peri-implant maintenance therapy (PIMT).

MATERIAL AND METHODS

A sample of 80 partially edentulous individuals rehabilitated with dental implants was invited to participate in a PIMT program (T1-prior to entering the PIMT program). After 11 years, 51 individuals remained regularly or irregularly adherent to PIMT (T2-last recall after 11 years) and were classified as regular (RC; n = 27) or irregular (IC; n = 24) compliers. Data of interest were analyzed using univariate and multivariate logistic regression analyses.

RESULTS

The incidence of peri-implant mucositis and peri-implantitis observed at T2 in the IC group (70.8% and 37.5%, respectively) were significantly higher than those observed in the RC group (37.0% and 11.1%, respectively). The incidence of peri-implant diseases was mostly attributable to potentially modifiable risk factors, as such: RC group-PM (p = 0.013); IC group-high plaque index (p < 0.001), irregular compliance (p < 0.001), the presence of PM (p = 0.015) and periodontitis (p < 0.039).

CONCLUSION

Regular compliance during PIMT had a strong effect in minimizing the incidence of peri-implant diseases. Increasing regular dental visits and improving oral hygiene would provide benefits for preventing peri-implant diseases.

What is the prevalence of peri-implantitis? A systematic review and meta-analysis

Background

Peri-implantitis is a usual finding but estimates of its prevalence fluctuate very much. This may be due to the wide variety of disease definitions. This systematic review aims to estimate the overall prevalence of peri-implantitis and the effect of different study designs, function times and use of probing depth on prevalence rate.

Methods

Following electronic and manual searches of the literature published from January 2005 to December 2021, data were extracted from the studies fitting the study criteria. Fifty-seven articles were included in this study.

Results

Prevalence of peri-implantitis was 19.53% (95% CI 12.87–26.19) at the patient-level, and 12.53% (95% CI 11.67–13.39) at the implant-level and it remains highly variable even following restriction to the clinical case definition. The use of probing depth like diagnostic criteria affected the prevalence data.

Conclusion

The results indicate that it remains essential the identification of the diagnostic markers for more accurate disease classification.

Prolonged Inhibition of Streptococcus mutans Growth and Biofilm Formation by Sustained Release of Chlorhexidine from Varnish Coated Dental Abutments: An in Vitro Study

Background

It has been confirmed that bacterial biofilm covering dental implants is the main microbial source causing preimplant infectious and inflammatory diseases. The purpose of this study was to evaluate the antibacterial/antibiofilm effect of chlorhexidine, incorporated into a sustained-release varnish of chlorhexidine (SRV-CHX) coating, on dental abutments.

Materials and Methods

Three kinds of dental abutments were used: a high-performance semi-crystalline engineering thermoplastic polyetheretherketone (PEAK) healing abutment, a titanium healing abutment, and a titanium permanent abutment. These abutments were coated with SRV-CHX or SRV-placebo and exposed daily to fresh cultures of Streptococcus mutans. The effect of SRV-CHX on S. mutans growth on agar plates was studied by measuring the zone of inhibition (ZOI) around each tested abutment every day for a period of 36 days. Biofilm formation on the SRV-CHX/placebo-coated abutments was detected using confocal laser scanning microscopy (CLSM) and high-resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray analysis (EDX), and monitored by crystal violet (CV) staining.

Results

SRV-CHX-coated abutments 2 and 3 were able to inhibit S. mutans growth for 34 days, while abutment 1 inhibited growth for 32 days. Abutment-associated biofilm formation was notably inhibited by SRV-CHX coating after 13 days of incubation with S. mutans. Finally, the biofilm formed around SRV-CHX-coated abutments was completely inhibited up to 12 days of abutment exposure to S. mutans.

Conclusion

Coating of dental abutments with SRV-CHX demonstrated long-term effective inhibition of S. mutans growth and biofilm formation on the abutment surface.

Longitudinal study on the effect of keratinized mucosal augmentation surrounding dental implants in preventing peri-implant bone loss

Background

Dental implant therapy is a well-established method of prosthetic rehabilitation of missing teeth. To maintain the health of the surrounding tissue, management of risk factors/indicators and daily maintenance are important. It still remains controversial whether a certain amount of keratinized mucosal width is essential for maintaining the health of peri-implant tissue. The purpose of this multicenter retrospective study was to assess the correlation between bone loss around dental implant and the amount of keratinized tissue width.

Methods

A total of 1,644 implants were evaluated. Data was collected about participants' general and dental history, as well as implant details. Bone resorption around implant was calculated from intra-oral radiographs taken after 1 year and more than 3 years of function. Implants were classified into three groups; received free gingival graft or apically repositioned flap surgery for increasing the keratinized mucosa ≥2 mm width (group A), keratinized mucosa width ≥2 mm (group B), and keratinized mucosa width <2 mm (group C). These data were analyzed by propensity score analysis and a generalized linear regression analysis was performed to compare the bone resorption among groups.

Results

Mean functional time was 55.8 months (SD = 20.5) in group A, 67.6 months (SD = 28.1) in group B, and 74.5 months (SD = 32.9) in group C. Mean bone resorption of groups A, B, and C were 0.08 mm (SD = 0.40), 0.18 mm (SD = 0.66), and 0.44 mm (SD = 0.40). Groups A and B had significantly lower bone resorption than group C.

Conclusion

The results in this study show the importance of keratinized mucosa in maintaining the peri-implant bone. Our findings also suggest that mucosal transplantation is useful, as opposed to narrowing of the keratinized mucosa.

In it together: Candida-bacterial oral biofilms and therapeutic strategies

Under natural environmental settings or in the human body, the majority of microorganisms exist in complex polymicrobial biofilms adhered to abiotic and biotic surfaces. These microorganisms exhibit symbiotic, mutualistic, synergistic, or antagonistic relationships with other species during biofilm colonization and development. These polymicrobial interactions are heterogeneous, complex and hard to control, thereby often yielding worse outcomes than monospecies infections. Concerning fungi, Candida spp., in particular, Candida albicans is often detected with various bacterial species in oral biofilms. These Candida-bacterial interactions may induce the transition of C. albicans from commensal to pathobiont or dysbiotic organism. Consequently, Candida-bacterial interactions are largely associated with various oral diseases, including dental caries, denture stomatitis, periodontitis, peri-implantitis, and oral cancer. Given the severity of oral diseases caused by cross-kingdom consortia that develop hard-to-remove and highly drug-resistant biofilms, fundamental research is warranted to strategically develop cost-effective and safe therapies to prevent and treat cross-kingdom interactions and subsequent biofilm development. While studies have shed some light, targeting fungal-involved polymicrobial biofilms has been limited. This mini-review outlines the key features of Candida-bacterial interactions and their impact on various oral diseases. In addition, current knowledge on therapeutic strategies to target Candida-bacterial polymicrobial biofilms is discussed.

Cross-kingdom microbial interactions in dental implant-related infections: is Candida albicans a new villain?

Candida albicans, an oral fungal opportunistic pathogen, has shown the ability to colonize implant surfaces and has been frequently isolated from biofilms associated with dental implant-related infections, possibly due to its synergistic interactions with certain oral bacteria. Moreover, evidence suggests that this cross-kingdom interaction on implant can encourage bacterial growth, leading to increased fungal virulence and mucosal damage. However, the role of Candida in implant-related infections has been overlooked and not widely explored or even considered by most microbiological analyses and therapeutic approaches. Thus, we summarized the scientific evidence regarding the ability of C. albicans to colonize implant surfaces, interact in implant-related polymicrobial biofilms, and its possible role in peri-implant infections as far as biologic plausibility. Next, a systematic review of preclinical and clinical studies was conducted to identify the relevance and the gap in the existing literature regarding the role of C. albicans in the pathogenesis of peri-implant infections.

Design and Evaluation of Web-Based Dental Implant Registry (DIR) for Better Clinical Outcomes

Introduction

Identification of dental implant system in undocumented patients is a major challenge for dentists due to the vast variety of tools and technologies that are used in dental care. It also takes a long time to identify the type of connection or length and diameter of implant. To obtain accurate and timely information, it is necessary to have a Dental Implant Registry (DIR). In the present study, a DIR was designed, developed, and evaluated at the Dental Implant Research Center of Tehran University of Medical Sciences.

Materials and Methods

This is an applied, developmental, and cross-sectional study that was conducted between 2018 and 2020. In the present study, after determining the objectives of DIR system, its conceptual model was designed by EDraw Max 7.9 software. Then, the registry was developed in Visual Studio 2018 environment with the C# programming language and, finally, it was evaluated by Nielsen's ten principles of usability assessment.

Results

After creating the registry, its data entry search and report functions were tested. Also, in the exploratory evaluation, the highest number of problems related to the principles of system clarity and compatibility between the system and real world was identified.

Conclusion

The web-based DIR created in C# programming language has the ability to gather data, provide report with different access levels, and send text messages to patients for follow-up. This tool enables physicians to quickly identify the components of dental implant. The web-based DIR also provides support for health research, quality assessment, and dental performance assessment.

Anti-inflammatory effects of the immobilization of SEMA4D on titanium surfaces in an endothelial cell/macrophage indirect coculture model

In this study, we established a procedure to prepare a Semaphorin4D (SEMA4D)-immobilized titanium surface and explored its effects on macrophage behaviors in an endothelial cell/macrophage indirect coculture model. The SEMA4D-bovine serum albumin complex was immobilized onto a preprocessed poly L-lysine titanium surface through NaOH hydrothermal treatment and self-assembly technology. All titanium specimens were examined for surface microstructure, surface element composition, and surface wettability by field emission scanning electron microscopy, x-ray photoelectron spectroscopy (XPS), and water contact angle measurement, respectively. Subsequently, we constructed an endothelial cell/macrophage indirect coculture model and evaluated the activation of NF-κB signaling pathway and the expression of proinflammatory cytokines (TNFα, IL-6, and IL-1β) in macrophages. In XPS analysis, the SEMA4D-immobilized titanium surface appeared as a loose porous structure covered with uniform film, which exhibited better hydrophilicity than the control smooth titanium surface. In the indirect coculture model, SEMA4D attenuated the activation of NF-κB signaling pathway of lipopolysaccharide-stimulated THP-1 macrophages, thereby downregulating the expression of proinflammatory cytokines in macrophages. In conclusion, SEMA4D could be immobilized on titanium surfaces through NaOH hydrothermal treatment and self-assembly technology. Meanwhile, SEMA4D immobilization altered the characteristics of the titanium surfaces, which negatively regulated macrophage behaviors in the endothelial cell/macrophage indirect coculture model.

Effectiveness of implant-supported fixed partial denture in patients with history of periodontitis: A systematic review and meta-analysis

AIM

This systematic review investigates the effectiveness of implant-supported fixed partial denture (IS-FPD) in patients with history of periodontitis (HP) vs. patients with no history of periodontitis (NHP).

METHODS

A literature search was performed on different databases on May 2020. Prospective and retrospective studies assessing survival (primary outcome), success and biological/mechanical complications of IS-FPDs in HP vs. NHP patients at ≥1 year after implant loading were evaluated. Meta-analyses were conducted by estimating hazard ratio (HR), risk ratio (RR) and standardized mean differences (SMD) with 95% confidence intervals (CI) using random effect models.

RESULTS

Of the initially identified 4096 articles, 349 underwent a full-text evaluation. Finally, 17 were included. Pooled data analyses showed that overall implant survival was significantly higher in the NHP than the HP group (HR = 2.06; 95% CI = 1.37-3.09; I²  = 0%). This difference was noted when follow-up ≥5 years. The risk of peri-implantitis was higher in HP than NHP patients (RR = 3.3; 95% CI = 1.31-8.3; I²  = 0%), whereas the mean marginal bone level change over time was not different between the groups (SMD = -0.16 mm; 95% CI = -1.04-0.73; I²  = 98%).

CONCLUSIONS

In partially edentulous patients receiving IS-FPDs, a history of periodontitis is associated with poorer survival rate and higher risk of peri-implantitis during a 5-10 years period after implant loading.

Prevalence and risk indicators for peri-implant diseases: A literature review

Peri-implant diseases are known as undesirable conditions that can occur after implant therapy. Although several risk indicators are becoming clear, the causes of peri-implant diseases have not been completely investigated. The purpose of this review was to summarize the prevalence and risk indicators for peri-implant diseases by referring to current papers from various angles. Many studies have reported the varied prevalence of peri-implant mucositis (23.9%-88.0% at the patient level and 9.7%-81.0% at the implant level) and peri-implantitis (8.9%-45% at the patient level and 4.8%-23.0% at the implant level). Additionally, several studies concluded that poor oral hygiene and lack of regular maintenance were strongly correlated with the development of both peri-implant mucositis and peri-implantitis. Diabetes and a history of periodontitis were revealed as risk indicators for peri-implantitis. However, there was no definitive conclusion about the correlations between peri-implant diseases and other factors such as smoking, the shape of the implant superstructure, and the condition of the keratinized mucosa. Further studies useful for evidence-based decision-making are needed for predictable implant therapy in the long term.

A Cross-Sectional Analysis on Factors Associated With Peri-Implant Pathologies at the Implant Level

Pathologies in peri-implant tissues are common and may disturb long-term implant supported rehabilitation. We aimed to evaluate the occurrence of such peri-implant diseases and their associated factors in this study. Peri-implantitis and mucositis were diagnosed based on clinical and radiological findings. Statistical analysis was performed with the X2 and logistic regression. Peri-implant mucositis and peri-implantitis were observed in 43.4% and 13.8% of patients with implants evaluated, respectively. Univariate analysis found associations with systemic changes (P = .016; yes), medication use (P = .010; yes), implant location (P < .0001; upper jaw), implant region (P = .008; posterior), previous augmentation procedure (P = .023; yes), time of prostheses use (P < .0001; >2 years), keratinized mucosa (P < .0001; absence); and gingival bleeding index (P = .005; >30%). In the multiple analysis, independent predictors were: >2 years of prostheses use (P < .0001; PR = 1.720), upper jaw location (P < .0001; PR = 1.421), gingival bleeding index >30% (P = .001; PR = 1.496), and use of medication (P < .0001; PR = 1.261). The frequency of peri-implant pathologies is high (approximately 57.2%) with several aspects of the occurrence being related to the patients' prosthesis. Prostheses type and the complexity of rehabilitation are worth highlighting. Factors include the location of the dental implant, gingival bleeding index, patient's use of medication(s), and the time of prostheses use.

Diagnosis of Biofilm-Associated Peri-Implant Disease Using a Fluorescence-Based Approach

Dental implants have become a routine component of daily dental practice and the demand for dental implants is expected to increase significantly in the future. Despite the high success rates of dental implants, failures do occur, resulting in discomfort, rampant destruction of the oral health, or painful and costly surgical replacement of a failed implant. Peri-implant diseases are inflammatory conditions affecting the soft/hard tissues surrounding a functional dental implant. Plenty of experimental evidence indicates that the accumulation of dental plaque at the soft tissue-implant interface and the subsequent local inflammatory response seems to be key in the pathogenesis of the peri-implant mucositis. Such peri-implant-soft tissue interface is less effective than natural teeth in resisting bacterial invasion, enhancing vulnerability to subsequent peri-implant disease. Furthermore, in certain individuals, it will progress to peri-implantitis, resulting in alveolar bone loss and implant failure. Although early diagnosis and accurate identification of risk factors are extremely important to effectively prevent peri-implant diseases, current systematic reviews revealed that a uniform classification and diagnostic methodology for peri-implantitis are lacking. Recent progress on fluorescence-based technology enabled rapid diagnosis of the disease and effective removal of plaques. Here, we briefly review biofilm-associated peri-implant diseases and propose a fluorescence-based approach for more accurate and objective diagnoses. A fluorescence-based diagnosis tool through headlights combined with special-filtered dental loupes may serve as a hands-free solution for both precise diagnosis and effective removal of plaque-biofilms.

Exploring the relationship among dental caries, nutritional habits, and peri-implantitis

BACKGROUND

A study was made of the prevalence, co-occurrence and association among caries, nutritional habits, and peri-implant disease, with an analysis of the influence of other patient and implant factors upon peri-implant disease.

METHODS

The included subjects underwent a clinical examination and were asked to complete a questionnaire. Demographic data and potential lifestyle/behavioral variables were collected. Clinical and radiographic assessment allowed calculation of the decayed, missing and filled teeth (DMFT) index and peri-implant diagnosis. Uni- and multivariate multinomial logistic regression analyses were applied to identify predictors of peri-implant disease.

RESULTS

A total of 169 patients with 311 implants were studied. At patient level, 92.2% of the subjects presented at least one carious lesion, whereas 22.5% and 56.2% were diagnosed with peri-implantitis and mucositis, respectively. Those patients with more than two caries had a higher risk of mucositis (OR = 3.33). Statistically significant associations for peri-implantitis included full mouth periodontal indexes, sugar-rich diets, keratinized mucosa width, number of missing teeth and interproximal untreated caries or fillings adjacent to implants.

CONCLUSION

High caries risk profiles and mucositis/peri-implantitis tended to accumulate within subjects. A sugar-enriched diet and untreated caries or fillings adjacent to implant sites may be further considered as risk indicators of peri-implantitis.

Osteoclast-mediated biocorrosion of pure titanium in an inflammatory microenvironment

Titanium (Ti) and alloys thereof are commonly utilized in biomedical settings owing to their desirable mechanical properties and good biocompatibility. However, when exposed to biological systems for extended periods of time, Ti still undergoes corrosion. In the present study, we therefore explore the impact of osteoclasts (OC) on the surface characteristics and corrosion of commercially pure Titanium (cpTi) in the context of lipopolysaccharide (LPS)-induced inflammation. We utilized tartrate resistant acidic phosphatase (TRAP) and fluorescence staining to assess OC properties, while scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), optical profilometer, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization tests, and inductively coupled plasma atomic emission spectrometry (ICP-AES) were used to evaluate metal microstructure, surface composition and roughness, electrochemical corrosion properties, and metal ion release. SEM findings demonstrated that the surface of cpTi exhibited micro-pitting as well as the presence of viable OCs. Correspondingly, cpTi that had been exposed to OCs exhibited reduced levels of Ti, oxygen, and oxides within the corroded regions relative to smooth Ti as measured via EDS and XPS. OC exposure was also associated with significant changes in cpTi surface roughness, a significant decrease in corrosion resistance, and a significant increase in the release of Ti ions into the surrounding medium. In summary, these findings indicate that OC culture on the surface of cpTi can directly corrode titanium and lead to the release of Ti ions.

Risk indicators for mucositis and peri-implantitis: results from a practice-based cross-sectional study

Purpose

This practice-based cross-sectional study aimed to investigate whether common risk indicators for peri-implant diseases were associated with peri-implant mucositis and peri-implantitis in patients undergoing supportive implant therapy (SIT) at least 5 years after implant restoration.

Methods

Patients exclusively restored with a single implant type were included. Probing pocket depth (PPD), bleeding on probing (BOP), suppuration, and radiographic bone loss (RBL) were assessed around implants. The case definitions were as follows: peri-implant mucositis: PPD ≥4 mm, BOP, no RBL; and peri-implantitis: PPD ≥5 mm, BOP, RBL ≥3.5 mm. Possible risk indicators were compared between patients with and without mucositis and peri-implantitis using the Fisher exact test and the Wilcoxon rank-sum test, as well as a multiple logistic regression model for variables showing significance (P<0.05).

Results

Eighty-four patients with 169 implants (observational period: 5.8±0.86 years) were included. A patient-based prevalence of 52% for peri-implant mucositis and 18% for peri-implantitis was detected. The presence of 3 or more implants (odds ratio [OR], 4.43; 95 confidence interval [CI], 1.36-15.05; P=0.0136) was significantly associated with an increased risk for mucositis. Smoking was significantly associated with an increased risk for peri-implantitis (OR, 5.89; 95% CI, 1.27-24.58; P=0.0231), while the presence of keratinized mucosa around implants was associated with a lower risk for peri-implantitis (OR, 0.05; 95% CI, 0.01-0.25; P<0.001).

Conclusions

The number of implants should be considered in strategies to prevent mucositis. Furthermore, smoking and the absence of keratinized mucosa were the strongest risk indicators for peri-implantitis in patients undergoing SIT in the present study.

Is oral lichen planus a risk factor for peri-implant diseases? A systematic review and meta-analysis

Background

To evaluate whether oral lichen planus (OLP) is a risk factor for peri-implant diseases (PIDs) with a systematic review and meta-analysis.

Methods

Five electronic databases including Medline, Embase, Web of Science, the Cochrane Library and Scopus were searched. The included studies are observational human studies written in English. The population of interest included those with/without OLP who received dental implant treatment. The follow-up time after implantation was from 1 month to 20 years. The quality of the included articles regarding risk of bias and methodology were assessed with the Newcastle-Ottawa Scale or the Agency for Healthcare Research and Quality. The data involving exposure (OLP), primary outcomes (implants having PIDs) and secondary outcomes (probing depth/PD, bleeding on probing/BOP and bone loss/BL) and potential confounders were extracted. Heterogeneity was assessed by I² test. Dichotomous data are expressed as the risk ratio (RR) and 95% confidence interval (CI) which were calculated with a fixed effect model.

Results

Of the 66 articles, two studies were enrolled and evaluated as high quality, which totally contained 68 participants receiving 222 (OLP vs. non-OLP, 112 vs. 110) implants with 12 to 120-month follow-up time. Proportions of implants with PIDs between OLP and non-OLP groups were as follows: 19.6% (22/112) vs. 22.7% (25/110) for PIM and 17.0% (19/112) vs. 10.9% (12/110) for PI. The meta-analysis revealed no recognizable difference in number of implants with PIDs (PI: RR = 1.49, 95% CI 0.77–2.90, P = 0.24; PIM:RR = 0.88, 95% CI 0.53–1.46, P = 0.61; PIDs: RR = 1.08, 95% CI 0.75–1.55, P = 0.68) or BOP (RR = 0.90, 95% CI: 0.70–1.15, P = 0.40) between OLP and non-OLP groups.

Conclusions

Available articles regarding the effects of OLP on PIDs remains very limited. Existing evidence does not support OLP as a suspected risk factor for PIDs. Large-scale prospective trials are required to validate the findings.

Changing the Focus to the Whole Patient instead of One Oral Disease: The Concept of Individualized Prevention

Oral diseases are highly prevalent and a global burden. Accordingly, their prevention appears essential. Recently, different strategies have been developed, mainly focusing on the presence of singular oral diseases or conditions. This article aims to construct a contemporary concept of individualized preventive care in dentistry whereby the focus is switched from viewing oral health in isolation to viewing the patient as a whole. The basis for individualized prevention measures is the case-oriented profile, including the synthesis of risk- and need-oriented parameters. The risk profile comprises different risk factors within the fields of systemic diseases, medications, and lifestyle that inherently pose a potential risk of complications (e.g., infectious endocarditis) and/or oral diseases (e.g., periodontitis). The needs profile includes factors originating from the aspects of oral diseases, dental restorations/appliances, and dental results with a potential risk of pathogenesis (e.g., the de novo development of caries) and/or the potential progression of oral diseases (e.g., an existing caries lesion). Based on these parameters, the general framework and content of prevention measures, as well as the maintenance interval, should be adapted to the individual patient. The implications of this concept might increase the safety, effectiveness, and efficiency of prevention in dental care. A further area of focus is primary prevention, that is, a focus on the preservation of oral health instead of a disease-related approach. However, clinical validation is needed to prove the benefits of the model presented. Individualized prevention promotes a shift from a disease-focused model to a whole-patient-focused model and provides a potential approach for establishing a contemporary concept for preventive care in dentistry.

Salivary Levels of Titanium, Nickel, Vanadium, and Arsenic in Patients Treated with Dental Implants: A Case-Control Study

Background: Recent articles have hypothesized a possible correlation between dental implants dissolution products and peri-implantitis. The null hypothesis tested in this case-control study was that there would be no differences in salivary concentrations of titanium (Ti), vanadium (V), nickel (Ni) and arsenic (As) ions among patients with dental implants, healthy (Group A) or affected by peri-implantitis (Group B), compared to subjects without implants and/or metallic prosthetic restorations (Group C). Methods: Inductively coupled plasma mass spectrometry was used to analyze saliva samples. One-way repeated-measure analysis of variance (ANOVA) was used to identify statistically significant differences in the salivary level of Ti, V, Ni and As between the three groups. Results: A total of 100 patients were enrolled in the study (42 males and 58 females), distributed in three groups: 50 patients in Group C, 26 patients in Group B and 24 patients Group B. In our study, concentrations of metallic ions were higher in Group A and B, compared to the control group, with the exception of vanadium. However, there were no statistically significant differences (p > 0.05) for metallic ions concentrations between Group A and Group B. Conclusions: Based on our results, there are no differences in titanium or other metals concentrations in saliva of patients with healthy or diseased implants.

Effect of cobalt ions on the interaction between macrophages and titanium

Inflammation and bone reduction around dental implants are described as peri‐implantitis and can be caused by an inflammatory response against bacterial products and toxins. Titanium (Ti) forms aggregates with serum proteins, which activate and cause release of the cytokine interleukin (IL‐1β) from human macrophages. It was hypothesized that cobalt (Co) ions can interact in the formation of pro‐inflammatory aggregates, formed by titanium. To test this hypothesis, we differentiated THP‐1 cells into macrophages and exposed them to Ti ions alone or in combination with Co ions to investigate if IL‐1β release and cytotoxicity were affected. We also investigated aggregate formation, cell uptake and human biopsies with inductively coupled plasma atomic emission spectroscopy and electron microscopy. Co at a concentration of 100 µM neutralized the IL‐1β release from human macrophages and affected the aggregate formation. The aggregates formed by Ti could be detected in the cytosol of macrophages. In the presence of Co, the Ti‐induced aggregates were located in the cytosol of the cultured macrophages, but outside the lysosomal structures. It is concluded that Co can neutralize the Ti‐induced activation and release of active IL‐1β from human macrophages in vitro. Also, serum proteins are needed for the formation of metal‐protein aggregates in cell medium. Furthermore, the structures of the aggregates as well as the localisation after cellular uptake differ if Co is present in a Ti solution. Phagocytized aggregates with a similar appearance seen in vitro with Ti present, were also visible in a sample from human peri‐implant tissue. © 2018 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A:2518–2530, 2018.

A prospective study of the clinical outcomes of peri-implant tissues in patients treated for peri-implant mucositis and followed up for 54 months

BACKGROUND

Peri-implant mucositis is very common and, when left untreated, can progress to the more serious condition of peri-implantitis. Therefore, early diagnosis, adequate treatment and, in particular, adherence to a peri-implant supportive therapy are extremely important for the management of peri-implant mucositis.

PURPOSE

Characterize the clinical conditions of peri-implant tissues in patients diagnosed with peri-implant mucositis after undergoing peri-implant supportive therapy for 54 months.

MATERIALS AND METHODS

Thirty-eight patients (131 dental implants) who received peri-implant supportive therapy, associated with oral hygiene instructions, were assessed at baseline and at 54 months for visible plaque and gingival bleeding indexes, probing depth and bleeding on probing. Data were statistically analyzed using the Chi-square test and relative risk assessment using a significance level set at 5%.

RESULTS

None of the independent variables evaluated (age, gender, smoking, type of prosthesis, time using the prosthesis, keratinized mucosa, phenotype peri-implant, classification of visible plaque index and classification of gingival bleeding index) presented significant associations with "worsening" or "improvement" of clinical parameters.

CONCLUSION

The implementation of peri-implant support therapy was not sufficient for the resolution of peri-implant mucositis, although reductions in clinical parameters with respect to baseline were observed and maintained during follow-up.

The prevalence of peri-implant diseases in patients with metabolic syndrome: a case-control study on an Italian population sample

BACKGROUND

The correlation of peri-implantitis with systemic diseases is still highly debated and controversial in literature. The objective of this work was to evaluate the possible association between peri-implant diseases and metabolic syndrome.

METHODS

In this case-control study, subjects healthy or affected by metabolic syndrome, with at least one dental implant with >5 years of functional loading were screened to detect peri-implant health or diseases. A complete full mouth periodontal and peri-implant examination at six sites was performed for each implant and standardized periapical X-ray were taken to evaluate marginal bone loss. Diagnostic Criteria of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions were applied. The analysis of variance (ANOVA) was used to compare means of recorded variables between the two groups, with a P<0.05 value considered statistically significant. Sub-group analysis was performed for smoking (smokers vs. non-smokers), sex (males vs. females), implant site (maxillary vs. mandible) and type of prostheses (single crown vs. bridge).

RESULTS

Forty-one patients were enrolled, divided into two groups, for a total of 132 dental implants: 71 in the metabolic syndrome group and 61 in the control group. The overall prevalence of peri-implant diseases (peri-implantitis + mucositis) in the two groups was, respectively, 93% vs. 63%, with an odds ratio (OR) of 7.4462 (95% CI: 2.6092; 21.2496) for the metabolic syndrome group (P<0.001).

CONCLUSIONS

Despite the limited sample, our results showed a statistically significant higher prevalence of peri-implant diseases in patients with metabolic syndrome compared to healthy patients. Further longitudinal studies are needed to verify this relationship.

Inhibition of the receptor for advanced glycation inhibits lipopolysaccharide-mediated High mobility group protein B1 and Interleukin-6 synthesis in human gingival fibroblasts through the NF-κB signaling pathway

AIMS

We investigated the effect of a specific inhibitor of the receptor for advanced glycation (FPS-ZM1) against lipopolysaccharide (LPS)-induced increase in expressions of high mobility group protein B1 (HMGB1) and interleukin-6 (IL-6) in human gingival fibroblasts (HGFs). Furthermore, we explored the potential molecular mechanisms and assessed the involvement of the NF-κB pathway in mediating the changes in the expressions of HMGB1 and IL-6 expression in response to LPS and FPS-ZM1.

METHODS

HGFs were cultured with enzymatic digestion-tissue explants method. The proliferation of LPS-stimulated HGFs pretreated with FPS-ZM1 at 24, 48, and 72 h was determined by cell counting kit 8 assay. The expressions of HMGB1 and IL-6 were measured using quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. Western blot analysis was used to assess the expressions of receptor for advanced glycation end products (RAGE) and NF-κB.

RESULTS

LPS enhanced the protein expression of RAGE in HGFs. At the same time, LPS stimulated mRNA and protein expressions of HMGB1 and IL-6 in HGFs. However, pretreatment with FPS-ZM1 attenuated these effects. Pretreatment with FPS-ZM1 (250, 500 nM) significantly inhibited the LPS-induced NF-κB activity.

CONCLUSION

FPS-ZM1 down-regulated the LPS-induced HMGB1 and IL-6 expression in HGFs through blocking NF-κB activation. FPS-ZM1 is a promising therapeutic agent for inflammatory diseases caused by oral bacteria.

Current weight of evidence of viruses associated with peri-implantitis and peri-implant health: A systematic review and meta-analysis

The pathological role of human herpesviruses (HHVs) (Epstein-Barr virus [EBV], Human cytomegalovirus [CMV], and Herpes simplex virus [HSV]) in peri-implant health needs clarification quantitatively. To determine the weight of evidence for HHVs in patients with peri-implantitis (PI) and substantiate the significance of HHVs in peri-implant inflammation, electronic databases including EMBASE, MEDLINE, Cochrane Oral Health Group Trials Register, and Cochrane Central Register of Controlled Trials were searched from 1964 up to and including November 2018. Meta-analyses were conducted for prevalence of HHVs in PI and healthy controls. Forest plots were generated that recorded risk difference (RD) of outcomes and 95% confidence intervals (CI). Five clinical studies were considered and included. Four clinical studies reported data on EBV while three clinical studies reported data on CMV. Considering the risk of these viruses in PI, significant heterogeneity for CMV (χ²  = 53.37, p < 0.0001, I²  = 96.25%) and EBV (χ²  = 14.14, p = 0.002, I²  = 78.79%) prevalence was noticed between PI and healthy control sites. The overall RD for only EBV (RD = 0.20, 95% CI, 0.01-0.40, p = 0.03) was statistically significant between both groups. Frequencies of the viruses were increased in patients with PI compared with healthy nondiseased sites. However, the findings of the present study should be interpreted with caution because of significant heterogeneity and small number of included studies.

The effect of antiresorptive drugs on implant therapy: Systematic review and meta-analysis

OBJECTIVES

A considerable portion of the adult population has received and/or is receiving treatment with antiresorptive drugs (ARDs). It is thus relevant to assess possible side effects of ARD intake in connection to various aspects of implant therapy. The aim of this study was to answer the focused question "In patients with systemic intake of ARDs, what is the outcome and complication rate of implant therapy including associated bone grafting procedures comparing to patients without systemic intake of ARDs?"

MATERIALS AND METHODS

Original studies fulfilled predefined inclusion criteria (e.g., case series, cohort studies, case-control studies, and controlled and/or randomized controlled clinical trials; retro- or prospective design; and ≥10 patients with systemic intake of ARDs). Various patient-, medication-, and intervention-related parameters [i.e., implant loss, grafting procedure complication/failure, peri-implant marginal bone levels/loss, medication-related osteonecrosis of the jaws (MRONJ), and peri-implantitis] were extracted, and meta-analyses and quality assessment were performed.

RESULTS

Twenty-four studies with bisphosphonate (BP) intake (mainly low dose for osteoporosis treatment) and seven studies on hormone replacement therapy (HRT), including ≥10 patients, and controls not taking the medication were identified. Furthermore, seven studies on MRONJ associated with implants were included. Meta-analyses based on four studies reporting on patient level and eight studies reporting on implant level showed no significant differences in terms of implant loss between patients on BPs (mainly low dose for osteoporosis treatment) and controls. Furthermore, low-dose BP intake did not compromise peri-implant marginal bone levels. Based on two studies, no negative effect of HRT was observed on the implant level, while HRT appeared to exert a marginally significant negative effect regarding implant survival on the patient level and regarding peri-implant marginal bone levels. Based on six studies reporting single-patient data, MRONJ in patients on BP for osteoporosis appeared in 70% of the cases >36 months after start of drug intake, while in patients with cancer, MRONJ appeared in 64% of the cases ≤36 months after first BP intake.

CONCLUSION

Low-dose oral BP intake for osteoporosis treatment, in general, does not compromise implant therapy, that is, patients on ARDs do not lose more implants nor get more implant-related complications/failures comparing to implant patients without BP intake. There is almost no information available on the possible effect on implant therapy of high-dose BPs or other widely used ARDs (e.g., denosumab), or on the success or safety of bone grafting procedures. Patients with high-dose ARD intake for management of malignancies, patients on oral BP over a longer period of time, and patients with comorbidities should be considered as high-risk patients for MRONJ.

A Peri-Implant Disease Risk Score for Patients with Dental Implants: Validation and the Influence of the Interval between Maintenance Appointments

Background: There is a need for tools that provide prediction of peri-implant disease. The purpose of this study was to validate a risk score for peri-implant disease and to assess the influence of the recall regimen in disease incidence based on a five-year retrospective cohort. Methods: Three hundred and fifty-three patients with 1238 implants were observed. A risk score was calculated from eight predictors and risk groups were established. Relative risk (RR) was estimated using logistic regression, and the c-statistic was calculated. The effect/impact of the recall regimen (≤ six months; > six months) on the incidence of peri-implant disease was evaluated for a subset of cases and matched controls. The RR and the proportional attributable risk (PAR) were estimated. Results: At baseline, patients fell into the following risk profiles: low-risk (n = 102, 28.9%), moderate-risk (n = 68, 19.3%), high-risk (n = 77, 21.8%), and very high-risk (n = 106, 30%). The incidence of peri-implant disease over five years was 24.1% (n = 85 patients). The RR for the risk groups was 5.52 (c-statistic = 0.858). The RR for a longer recall regimen was 1.06, corresponding to a PAR of 5.87%. Conclusions: The risk score for estimating peri-implant disease was validated and showed very good performance. Maintenance appointments of < six months or > six months did not influence the incidence of peri-implant disease when considering the matching of cases and controls by risk profile.

Covalently-Linked Hyaluronan versus Acid Etched Titanium Dental Implants: A Crossover RCT in Humans

Biochemical modification of titanium surfaces (BMTiS) entails immobilization of biomolecules to implant surfaces in order to induce specific host responses. This crossover randomized clinical trial assesses clinical success and marginal bone resorption of dental implants bearing a surface molecular layer of covalently-linked hyaluronan in comparison with control implants up to 36 months after loading. Patients requiring bilateral implant rehabilitation received hyaluronan covered implants in one side of the mouth and traditional implants in the other side. Two months after the first surgery, a second surgery was undergone to uncover the screw and to place a healing abutment. After two weeks, the operator proceeded with prosthetic procedures. Implants were evaluated by periapical radiographs and the crestal bone level was recorded at mesial and distal sites—at baseline and up to 36 months. One hundred and six implants were positioned, 52 HY-coated, and 48 controls were followed up. No differences were observed in terms of insertion and stability, wound healing, implant success, and crestal bone resorption at any time considered. All interventions had an optimal healing, and no adverse events were recorded. This trial shows, for the first time, a successful use in humans of biochemical-modified implants in routine clinical practice and in healthy patients and tissues with satisfactory outcomes.

Prevalence of peri-implant disease and risk indicators in a Japanese population with at least 3 years in function-A multicentre retrospective study

OBJECTIVES

The aim of this study was to evaluate the prevalence of peri-implant disease and analyze risk indicators in Japanese subjects with ≥3 years of implant function.

MATERIAL AND METHODS

Five hundred and forty-three subjects treated with 1,613 implants were evaluated. Information was collected about the patients' physical and dental history, as well as implant details. Peri-implant evaluation included probing depth, bleeding on probing (BoP), suppuration (Sup), and keratinized tissue width. Bone loss was calculated from intra-oral radiographs taken after 1 year and more than 3 years of function. Implants were classified into three groups: healthy, peri-implant mucositis (BoP without bone loss), and peri-implantitis (BoP and/or Sup with bone loss >1 mm). These data were analyzed by multivariable multinomial logistic regression.

RESULTS

The prevalence of peri-implant mucositis and peri-implantitis at the subject level was 23.9% and 15.8%, respectively. An association was found between peri-implant mucositis and plaque control record (PCR) >20% and keratinized tissue width <2 mm. Peri-implantitis was associated with PCR >20%, smoking, insertion in the maxilla, and keratinized tissue width <2 mm.

CONCLUSIONS

Within the limitations of this study, the prevalence of peri-implant diseases was elucidated in a Japanese population. Peri-implant mucositis was associated with poor oral hygiene and less keratinized tissue. Poor oral hygiene, smoking, insertion in the maxilla, and less keratinized tissue were risk indicators for peri-implantitis.

The role of bacterial biofilm and mechanical forces in modulating dental implant failures

Currently many assume that bacteria are the primary etiological factor associated with failure of titanium dental implants. However, emerging data indicates a possible role for mechanical forces in implant failure. This study is based on the hypothesis that the synergistic effect of mechanical forces and bacterial biofilm can lead to surface damage resulting in in vivo release of metallic particles. The primary aim of the study was to develop a dynamic fatigue test method for dental implants immersed in wet environments such as; (i) 0.01 M phosphate buffer saline (PBS); (ii) lactic acid (pH = 5); (iii) bacterial polyculture. Four dental implants each were subjected to fatigue loading from 45 N to 450 N at 4 Hz for 2 million cycles while immersed in (i) PBS (negative control); (ii) bacterial culture (test); and (iii) lactic acid (positive control). Post-testing, optical microscopy, x-ray photoelectron spectroscopy, and electrochemical corrosion tests were performed to evaluate the surface morphology, chemistry, and potential, respectively, of titanium implants. Post-testing, surface discoloration was evident in all three groups. However, the surface damage was further established in XPS analyses of test specimens, which showed that the interplay of bacterial biofilm and mechanical forces resulted in thinning of the TiO₂. Lower corrosion potential (Ecorr) of the test specimens compared to positive and negative controls also illustrated damage to the oxide layer. However, other electrochemical parameters such as linear polarization resistance (LPR) and corrosion rate (CR) were comparable among the groups indicating the corrosion resistance post-testing. The synergistic effect of cyclic occlusal loading and bacteria biofilm could negatively affect the surface of titanium dental implants.

Longitudinal study on risk indicators for peri-implantitis using survival-time analysis

PURPOSE

The purpose of this study was to evaluate the incidence of peri-implantitis and to identify potential associated risk indicators.

METHODS

This longitudinal study included 477 patients treated with 1420 implants. Medical and dental histories were evaluated in all patients. The location, size, connection type, surgical protocol, use of prosthesis splinting and fixation type were evaluated for each implant. In peri-implant evaluation, minimum keratinized tissue width around implants, peri-implant probing depths, peri-implant bleeding and peri-implant suppuration were assessed. Bone resorption around implants was evaluated with intraoral radiographs at baseline and at follow-up examinations. The study endpoint was peri-implantitis, which was defined as the presence of bleeding on probing and/or suppuration with bone resorption >1mm, in accordance with previous studies. Data were analyzed with mixed-effects Cox models.

RESULTS

Peri-implantitis occurred in 15.3% of patients and 9.2% of implants. The overall 5- and 10-year cumulative implant survival rates were 0.95 (95% confidence interval [CI]: 0.93-0.96) and 0.83 (95% CI: 0.8-0.87), respectively. Age (hazard ratio [HR]=0.94, 95% CI: 0.90-0.98, p<0.01), plaque control record >20% (HR=2.61, 95% CI: 1.02-6.67, p=0.04), maxillary placement (HR=1.90, 95% CI: 1.11-3.23, p=0.02) and number of occlusal supports (HR=0.87, 95% CI: 0.77-0.99, p=0.03) were significantly correlated with peri-implantitis development.

CONCLUSIONS

Within the limitations of this longitudinal study on risk indicators for peri-implantitis, age, inadequate plaque control, insertion in the maxilla and less occlusal support of natural teeth correlated with peri-implantitis development.

Titanium release in peri-implantitis

OBJECTIVES

The aim of this study was to investigate the titanium (Ti) content of biopsies from patients with severe peri-implantitis or controls without Ti exposure.

BACKGROUND

Peri-implantitis is considered to be an infectious disease, but recent studies have shown that Ti can aggravate inflammation in combination with bacterial products. The Ti content of peri-implantitis and periodontitis (controls) tissue is unknown.

METHODS

Thirteen patients referred for peri-implantitis and eleven for periodontitis treatment were included in the study. Disease severity was obtained from dental records. Biopsies were taken from both groups and chemically analysed with inductively coupled plasma mass spectrometry for Ti content. Additionally, two patients with peri-implantitis and two with periodontitis were recruited and their biopsies were analysed microscopically with light microscopy, transmission electron microscopy and scanning electron microscopy with element analysis to investigate the presence of particulate Ti.

RESULTS

All patients lost one or more implants despite undergoing peri-implant or treatment. Peri-implantitis tissue contained significantly higher concentrations of Ti than control samples with a mean ± SD of 98.7 ± 85.6 and 1.2 ± 0.9 μg/g, respectively. Particulate metal was identified in peri-implantitis and control biopsies, but element analyses could confirm only the presence of Ti in peri-implantitis tissue.

CONCLUSION

We showed that high contents of particulate and submicron Ti were present in peri-implantitis tissue. These high Ti contents in peri-implant mucosa can potentially aggravate inflammation, which might reduce the prognosis of treatment interventions.

Investigation of peri-implant tissue conditions and peri-implant tissue stability in implants placed with simultaneous augmentation procedure: a 3-year retrospective follow-up analysis of a newly developed bone level implant system

Background

Guided bone regeneration (GBR) has been proven to be a reliable therapy to regenerate missing bone in cases of atrophy of the alveolar crest. The aim of the present retrospective analysis was to assess peri-implant tissue conditions and document peri-implant tissue stability in C-Tech implants when placed simultaneously with a GBR augmentation procedure.

Methods

A total of 47 implants, which were placed simultaneously with a GBR procedure with a synthetic bone substitute material in 20 patients, were investigated clinically and radiologically at least 3 years after loading. Implant survival, the width and thickness of peri-implant keratinized gingiva, probing depth, bleeding on probing (BOP), the Pink Esthetic Score (PES), peri-implant bone loss, and the presence of peri-implant osteolysis were determined.

Results

The follow-up investigation revealed a survival rate of 100% and only low median rates for probing depths (2.7 mm) and BOP (30%). The mean PES was 10.1 from the maximum value of 14. No osseous peri-implant defects were obvious, and the mean bone loss was 0.55 mm.

Conclusions

In conclusion, implants placed in combination with a GBR procedure can achieve long-term stable functionally and esthetically satisfying results for replacing missing teeth in cases of atrophy of the alveolar crest.

A novel non-surgical method for mild peri-implantitis- a multicenter consecutive case series

AIM

The aim of the present study was to evaluate the effect on peri-implant mucosal inflammation from the use of a novel instrument made of chitosan in the non-surgical treatment of mild peri-implantitis across several clinical centers.

MATERIALS AND METHODS

In this 6-month multicenter prospective consecutive case series performed in six different periodontal specialist clinics, 63 implants in 63 patients were finally included. The subjects had mild peri-implantitis defined as radiographic bone loss of 1-2 mm, pocket probing depth (PPD) ≥4 mm and a positive bleeding on probing (mBoP) score. The patients were clinically examined at baseline and after 2, 4, 12 and 24 weeks, and radiographs were taken at baseline and at 3 and 6 months. Treatment of the implants with the chitosan brush seated in an oscillating dental drill piece was performed at baseline and at 3 months. Reductions in the clinical parameters (PPD and mBoP) were compared between baseline and the later examination time points.

RESULTS

Significant reductions in both PPD and mBoP were observed at all time points compared with the baseline clinical measurements (p < 0.001). The mean PPD and mBoP at baseline were 5.15 mm (4.97; 5.32) and 1.86 (1.78; 1.93), respectively, whereas the mean PPD and mBoP at 6 months were 4.0 mm (3.91; 4.19) and 0.64 (0.54; 0.75), respectively. Stable reductions in PPD and mBoP were evident up to 6 months after the initial treatment and 3 months after the second treatment. All 63 implants were reported to have stable radiographic levels of osseous support.

CONCLUSIONS

This case series demonstrated that an oscillating chitosan brush is safe to use and seems to have merits in the non-surgical treatment of dental implants with mild peri-implantitis. To measure the effectiveness of the method, a multicenter randomized clinical trial needs to be undertaken.

Function of Platelet-Induced Epithelial Attachment at Titanium Surfaces Inhibits Microbial Colonization

The aim of this study was to evaluate the barrier function of platelet-induced epithelial sheets on titanium surfaces. The lack of functional peri-implant epithelial sealing with basal lamina (BL) attachment at the interface of the implant and the adjacent epithelium allows for bacterial invasion, which may lead to peri-implantitis. Although various approaches have been reported to combat bacterial infection by surface modifications to titanium, none of these have been successful in a clinical application. In our previous study, surface modification with protease-activated receptor 4–activating peptide (PAR4-AP), which induced platelet activation and aggregation, was successful in demonstrating epithelial attachment via BL and epithelial sheet formation on the titanium surface. We hypothesized that the platelet-induced epithelial sheet on PAR4-AP–modified titanium surfaces would reduce bacterial attachment, penetration, and invasion. Titanium surface was modified with PAR4-AP and incubated with platelet-rich plasma (PRP). The aggregated platelets released collagen IV, a critical BL component, onto the PAR4-AP–modified titanium surface. Then, human gingival epithelial cells were seeded on the modified titanium surface and formed epithelial sheets. Green fluorescent protein (GFP)–expressing Escherichia coli was cultured onto PAR4-AP–modified titanium with and without epithelial sheet formation. While Escherichia coli accumulated densely onto the PAR4-AP titanium lacking epithelial sheet, few Escherichia coli were observed on the epithelial sheet on the PAR4-AP surface. No bacterial invasion into the interface of the epithelial sheet and the titanium surface was observed. These in vitro results indicate the efficacy of a platelet-induced epithelial barrier that functions to prevent bacterial attachment, penetration, and invasion on PAR4-AP–modified titanium.