Quantification of titanium and zirconium elements in oral mucosa around healthy dental implants: a case-control pilot study.

OBJECTIVES: Metallic particles are detected in different sites of the oral cavity, mainly in patients with peri-implantitis lesions. The aim of this pilot study was to analyze the levels of titanium and zirconium elements in the oral mucosa around healthy implants and to investigate the impact of titanium exogenous contamination on the measurements. MATERIALS AND METHODS: Forty-one participants were included in this three-phase study. Two groups of subjects were defined according to presence of titanium or zirconia implants (n: 20) or without any implants nor metallic restorations (n:21). Thirteen patients (n: 5 with zirconia implant; n: 3 with titanium implants; n: 5 control group) took part to the first part designed to optimize and validate the method of detecting titanium (Ti) and zirconium (Zr) elements in the oral mucosa and gingival tissues by the Inductively Coupled Plasma Mass Spectrometry (ICPMS). The second phase compared the levels of Ti and Zr concentrations in patients with implants (n: 12) and without implants (n: 6) who were controlled for their intake of titanium dioxide (TiO2). The last step included ten control subjects without any metallic devices to measure the concentration of Ti and Zr before and after having candies containing TiO2. RESULTS: In the first phase, concentrations of Ti and Zr were below the limit of detection (LOD) in most cases, 0.18 µg/L and 0.07 µg/L respectively. In the titanium group, two out of three subjects displayed concentrations above the LOD, 0.21 µg/L and 0.66 µg/L. Zr element was only found in patients with zirconia implants. After controlling the intake of TiO2, all concentrations of Ti and Zr were below the limit of quantification (LOQ). Moreover, in patients with no implants, the Ti concentration in gingiva cells was superior for 75% of the samples after having a TiO2 diet. CONCLUSIONS: Zirconium was only found in patients with zirconia implants, whereas titanium was detected in all groups even in subjects with no titanium implants. Zirconium and titanium elements were not detected in patients who were controlled for their intake of food and their use of toothpaste irrespective of the presence of implants or not. For 70% of the patients, the titanium detection was directly influenced by the intake of TiO2 contained candies. CLINICAL RELEVANCE: When analyzing titanium particles, it is necessary to pay attention to the risk of contamination bias brought by external products. When this parameter was controlled, no titanium particles were detected around clinically healthy implants.

Two-piece zirconia implants supporting all-ceramic crowns: Six-year results of a prospective cohort study.

OBJECTIVES: The aim of this prospective clinical trial was to present the 6-year outcomes of a two-piece yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) implant system in partially edentulous patients. MATERIAL AND METHODS: Forty-nine two-piece zirconia implants were placed in 32 patients systemically healthy. Zirconia abutments were connected with adhesive resin cement. Single-unit full-ceramic crowns were cemented. The cases have been followed for an average of 82.2 ± 5.86 months after loading (range 74.93-92.26 months). RESULTS: 24 participants with 39 implants were available for examination 6 years after loading. The cumulative implant survival rate was 83%. On an implant level, the cumulative mechanical complication rate was 17.5%, the cumulative technical complication rate was 13%, and the biological complication rate was 8%. After 6 years, subjects reported good satisfaction with the treatment: 3.7 ± 4.4 on a visual analog scale (VAS) from 0 to 100 mm. CONCLUSIONS: Within the limitations of this prospective case series study, two-piece zirconia implants could offer an alternative for treatment of single edentulous spaces in the posterior region. The major complication on the long term of this pioneering system was the abutment fracture; however, due to the versatility of a two-piece implant system, replacement of the broken parts was possible.

Removal of osseointegrated dental implants: a systematic review of explantation techniques.

OBJECTIVES: This systematic review aims to evaluate current literature regarding available techniques for removal of osseointegrated implants in terms of explantation's success, complications, and bone loss. MATERIAL AND METHODS: Two reviewers conducted a systematic literature search through electronic databases (PubMed and EMBASE), complimented by manual and grey literature searches. Successful explantation was defined as the primary outcome. Complications and availability of residual bone for immediate implantation were defined as secondary outcomes. RESULTS: Eighteen articles, comprising 372 implants and 241 patients, were included. Five techniques were identified: reverse torque, trephines, burs, piezosurgery, and laser-assisted explantation. Peri-implantitis was the most common reason for explantation, followed by crestal bone loss, fracture, and malpositioning. The reverse torque was the most frequently reported technique (284 implants) with 87.7% success rate. Burs were used for explantation of 49 implants with a 100% success rate, while trephines were utilized for removal of 35 implants with 94% success. Piezosurgery (11 implants) and Er.Cr:YSGG laser (1 implant) showed 100% success. One study reported perforation of the sinus floor following trephine explantation, while another reported fracture of 3 implants following reverse torque application. Further analysis was hindered by the quality of the available studies and their lack of data. CONCLUSIONS: Reverse torque seems the most conservative, and in the authors' opinion, should be the first choice for explantation despite its inferior success rate. Additional studies with randomized controlled designs and larger sample sizes are required. CLINICAL RELEVANCE: Dental implants have become the leading choice to replace missing teeth with gradually increasing numbers of complications and failures. An effective, conservative, and economic explantation technique is necessary to allow a successive implant placement.

What is the impact of titanium particles and biocorrosion on implant survival and complications? A critical review.

OBJECTIVES: To compile the current evidence regarding the association between the release of titanium particles and biologic complications of dental implants. MATERIAL AND METHODS: This is a critical review. We searched the literature using the terms "corrosion," "allergy," "hypersensitivity," or "particles" together with "titanium," "Ti," "TiO2. " The bibliographies of identified publications and previously published review articles were scanned to find additional related articles. We included clinical studies, in vivo and in vitro experiments. RESULTS: Titanium particles and degradation products of titanium have been detected in oral and nonoral tissues. Particles are released from surfaces of dental implants because of material degradation in a process called tribocorrosion. It involves mechanical wear and environmental factors, notably contact to chemical agents and interaction with substances produced by adherent biofilm and inflammatory cells. In vitro, titanium particles can interfere with cell function and promote inflammation. A temporal association between exposure to titanium and occurrence of tissue reactions suggested hypersensitivity in a limited number of cases. However, there is poor specificity as the observed reactions could be initiated by other factors associated with the placement of implants. Titanium particles are commonly detected in healthy and diseased peri-implant mucosa alike, at low levels even in gingiva of individuals without titanium implants. Rather than being the trigger of disease, higher concentrations of titanium in peri-implantitis lesions could be the consequence of the presence of biofilms and inflammation. CONCLUSION: There is an association between biocorrosion, presence of titanium particles, and biological implant complications, but there is insufficient evidence to prove a unidirectional causal relationship.

Group 4 ITI Consensus Report: Risks and biologic complications associated with implant dentistry.

OBJECTIVES: The aim of Working Group 4 was to address topics related to biologic risks and complications associated with implant dentistry. Focused questions on (a) diagnosis of peri-implantitis, (b) complications associated with implants in augmented sites, (c) outcomes following treatment of peri-implantitis, and (d) implant therapy in geriatric patients and/or patients with systemic diseases were addressed. MATERIALS AND METHODS: Four systematic reviews formed the basis for discussion in Group 4. Participants developed statements and recommendations determined by group consensus based on the findings of the systematic reviews. These were then presented and accepted following further discussion and modifications as required by the plenary. RESULTS: Bleeding on probing (BOP) alone is insufficient for the diagnosis of peri-implantitis. The positive predictive value of BOP alone for the diagnosis of peri-implantitis varies and is dependent on the prevalence of peri-implantitis within the population. For patients with implants in augmented sites, the prevalence of peri-implantitis and implant loss is low over the medium to long term. Peri-implantitis treatment protocols which include individualized supportive care result in high survival of implants after 5 years with about three-quarters of implants still present. Advanced age alone is not a contraindication for implant therapy. Implant placement in patients with cancer receiving high-dose antiresorptive therapy is contraindicated due to the associated high risk for complications. CONCLUSIONS: Diagnosis of peri-implantitis requires the presence of BOP as well as progressive bone loss. Prevalence of peri-implantitis for implants in augmented sites is low. Peri-implantitis treatment should be followed by individualized supportive care. Implant therapy for geriatric patients is not contraindicated; however, comorbidities and autonomy should be considered.

The diagnosis of peri-implantitis: A systematic review on the predictive value of bleeding on probing.

OBJECTIVES: Bleeding on gentle probing (BOP) is the key parameter to the diagnosis of mucositis, while changes in crestal bone levels, along with clinical signs of inflammation, are required for the diagnosis of peri-implantitis. This systematic review and meta-analysis focused on the evaluation of BOP as a predictive measure for peri-implantitis. MATERIALS AND METHODS: An electronic search was performed through Medline and EMBASE databases, followed by a hand search through previous reviews and reference lists. Screening, study selection, data extraction and evaluation of publication bias were conducted by two independent examiners. Clinical studies reporting on the prevalence of peri-implantitis, BOP and/or suppuration (SUP) after more than 1 year of functional loading were selected. Meta-analyses were conducted to combine the proportions of peri-implantitis among BOP- and/or SUP-positive subjects and implants across studies. Subgroups were created and compared to investigate potential sources of heterogeneity. RESULTS: Thirty-one studies were selected for analysis. Inconsistent definitions of peri-implantitis were reported across the studies. Twenty-nine studies reported data on implant-level and twenty publications reported on subject-level. The combined proportion of peri-implantitis was 24.1% (95% CI 19.3-29.7) in BOP-positive implants and 33.8% (95% CI 26.7-41.6) for BOP-positive cases. However, the degree of variability among studies was high; the prediction intervals were 10.3-69.3 and 6.9-57.8, respectively. Evidence of asymmetry or publication bias could not be statistically detected. Short observation periods were significantly associated with lower proportions of peri-implantitis among BOP-positive implants. CONCLUSIONS: For BOP-positive implants, there was a 24.1% chance to be diagnosed with peri-implantitis; while for BOP-positive patients, there was a 33.8% probability to be diagnosed with peri-implantitis. This probability varied across study populations. Clinicians should be aware of the considerable false-positive rate of BOP to diagnose peri-implantitis.

Group 5 ITI Consensus Report: Digital technologies.

OBJECTIVES: Working Group 5 was assigned the task to review the current knowledge in the area of digital technologies. Focused questions on accuracy of linear measurements when using CBCT, digital vs. conventional implant planning, using digital vs. conventional impressions and assessing the accuracy of static computer-aided implant surgery (s-CAIS) and patient-related outcome measurements when using s-CAIS were addressed. MATERIALS AND METHODS: The literature was systematically searched, and in total, 232 articles were selected and critically reviewed following PRISMA guidelines. Four systematic reviews were produced in the four subject areas and amply discussed in the group. After emendation, they were presented to the plenary where after further modification, they were accepted. RESULTS: Static computer-aided surgery (s-CAIS), in terms of pain & discomfort, economics and intraoperative complications, is beneficial compared with conventional implant surgery. When using s-CAIS in partially edentulous cases, a higher level of accuracy can be achieved when compared to fully edentulous cases. When using an intraoral scanner in edentulous cases, the results are dependent on the protocol that has been followed. The accuracy of measurements on CBCT scans is software dependent. CONCLUSIONS: Because the precision intraoral scans and of measurements on CBCT scans and is not high enough to allow for the required accuracy, s-CAIS should be considered as an additional tool for comprehensive diagnosis, treatment planning, and surgical procedures. Flapless s-CAIS can lead to implant placement outside of the zone of keratinized mucosa and thus must be executed with utmost care.

Zirconia dental implants: where are we now, and where are we heading?

Despite decades of titanium as the gold standard in oral implantology, the search for alternatives has been growing. High esthetic standards and increasing incidence of titanium allergies, along with a rising demand for metal-free reconstructions, have led to the proposal of ceramics as potential surrogates. Following numerous experimental studies, zirconium dioxide (zirconia) has earned its place as a potential substitute for titanium in implantology. Yet, despite zirconia's excellent biocompatibility and tissue integration, low affinity to plaque and favorable biomechanical properties, early failures were significantly higher for zirconia implants than for titanium implants. Technical failure as a result of fracture of the material is also a major concern. So far, zirconia implants have been mainly manufactured as one-piece implant systems because of the material's limitations. Nevertheless, various two-piece systems have been progressively emerging with promising results. Screw-retained abutments are desirable but present a major technical challenge. Innovation and technical advances will undoubtedly lead to further improvement in the reliability and strength of zirconia implants, allowing for novel designs, connections and reconstructions. Additional clinical studies are required to identify all relevant technical and biological factors affecting implant success and patients' satisfaction. However, the evidence for a final verdict is, at present, still incomplete.

A systematic review of the clinical survival of zirconia implants.

OBJECTIVES: The aim of this review was to evaluate the clinical success and survival rates of zirconia ceramic implants after at least 1 year of function and to assess if there is sufficient evidence to justify using them as alternatives to titanium implants. MATERIALS AND METHODS: An electronic search in MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Clinical Trials (CENTRAL) databases was performed in April 2015 by two independent examiners to retrieve clinical studies focusing on the survival rate of zirconia implants after at least 1 year of function. Implant survival was estimated using the overall proportion reported in the studies with a Clopper-Pearson 95 % confidence interval (random effect model with a Der-Simonian Laird estimate). RESULTS: Fourteen articles were selected out of the 1519 titles initially screened. The overall survival rate of zirconia one- and two-piece implants was calculated at 92 % (95 % CI 87-95) after 1 year of function. The survival of implants at 1 year for the selected studies revealed considerable heterogeneity. CONCLUSIONS: In spite of the unavailability of sufficient long-term evidence to justify using zirconia oral implants, zirconia ceramics could potentially be the alternative to titanium for a non-metallic implant solution. However, further clinical studies are required to establish long-term results, and to determine the risk of technical and biological complications. Additional randomized controlled clinical trials examining two-piece zirconia implant systems are also required to assess their survival and success rates in comparison with titanium as well as one-piece zirconia implants. CLINICAL RELEVANCE: Zirconia implants provide a potential alternative to titanium ones. However, clinicians must be aware of the lack of knowledge regarding long-term outcomes and specific reasons for failure.

Pro-inflammatory cytokines at zirconia implants and teeth. A cross-sectional assessment.

OBJECTIVES: The aim of this study was to compare the expression of host-derived markers in peri-implant/gingival crevicular fluid (PCF/GCF) and clinical conditions at ceramic implants and contralateral natural teeth. As a secondary objective, we compared zirconia implants with titanium implants. METHODS: One zirconia implant (ZERAMEX® Implant System) and one contralateral natural tooth were examined in 36 systemically healthy subjects (21 males, 15 females, mean age 58). The levels of Il-1ß, Il-1RA, Il-6, Il-8, Il-17, b-FGF, G-CSF, GM-CSF, IFNÉ£, MIP-1ß, TNF-α, and VEGF were assessed in PCF/GCF using the Bio-Plex 200 Suspension Array System. The plaque index (PI), gingival index (GI), probing depth (PD), and bleeding on probing (BOP) were assessed at six sites around each implant or tooth. Titanium implants were also assessed when present (n = 9). RESULTS: The zirconia implants were examined after a loading period of at least 1.2 years (average 2.2 years). The mean PI was significantly lower at zirconia implants compared to teeth (p = 0.003), while the mean GI, PD, and BOP were significantly higher (p < 0.001). A correlation was found in the expression of Il-1RA, Il-8, G-CSF, MIP-1ß, and TNF-α at zirconia implants and teeth. The levels of IL-1ß and TNF-α were significantly higher at zirconia implants than at teeth. No significant differences were found between zirconia and titanium implants. A correlation was found between the levels of IL-1RA, IL-8, GM-CSF, and MIP-1ß at zirconia and titanium implants. CONCLUSIONS: The correlation in the expression of five biomarkers at zirconia implants and teeth, and of four biomarkers at zirconia and titanium implants, is compatible with the existence of a patient-specific inflammatory response pattern. Higher mean GI, PD, and BOP around implants suggests that the peri-implant mucosa may be mechanically more fragile than the gingiva. CLINICAL RELEVANCE: Similar expression of selected biomarkers at zirconia implants and teeth and at zirconia and titanium implants reflects existence of patient-specific inflammatory response patterns.