Influence of Implant Surfaces on Peri-Implant Diseases - A Systematic Review and Meta-Analysis

OBJECTIVES

The aim of this systematic review and meta-analysis was to evaluate the current literature on the effect of implant surface characteristics on peri-implant marginal bone levels (MBL), soft tissue periodontal parameters, peri-implantitis, and implant failure rates.

MATERIALS AND METHODS

Randomized controlled trials were searched in electronic databases. Risk of bias within the selected studies was assessed using the Risk of Bias Tool 2. Meta-analyses were performed using Review Manager software for studies with similar comparisons reporting same outcome measures.

RESULTS

Ten randomized control trials were included in the present review. The primary outcome of changes in peri-implant MBL favoured implants with machined surfaces, however, the difference was not statistically significant (P = .18). The changes in probing pocket depths significantly favoured the use of machined surfaces (P = .01), while the implant failure rates favoured roughened surface implants. However, the difference was not statistically significant (P = .09).

CONCLUSION

Machined surface implants were favoured in terms of lesser peri-implant MBL, though the difference was not significant. The analysis also demonstrated limited favourable outcomes in terms of periodontal parameters for machined surfaces, with slightly significantly better outcomes in terms of probing pocket depths. However, rough surface implants tended to display a lower implant failure.

Marginal bone loss in dental implants: A literature review of risk factors and treatment strategies for prevention

PURPOSE

Marginal bone loss (MBL) occurs in the periapical cervical bone after dental implant placement and abutment connection. MBL may not result in peri-implantitis; however, it is always accompanied by MBL. Recent studies have demonstrated that early MBL is a predictor of peri-implantitis. In this narrative review, we aimed to provide an evidence base for recommended treatment strategies for clinicians to prevent MBL.

STUDY SELECTION

We reviewed the recent literature and performed a narrative synthesis of the evidence, focusing on available systematic reviews and meta-analyses of implant marginal bone resorption.

RESULTS

The available evidence indicates that certain biological, material, and technical factors can influence MBL and consequently dictate the risk of developing peri-implant disease in later years. The order of the impact of the strength of each factor is unknown. Current recommendations to prevent MBL include controlling patients' smoking and hemoglobin A1c levels to sufficiently low levels before surgery and throughout their lifetime. Regarding the material, a platform-switching, conical-connecting implant system, and an abutment with a height of at least 2 mm should be selected. Placement should be performed using techniques that ensure sufficient soft tissue (keratinized gingival width > 2 mm, supracrestal tissue height > 3 mm), and non-undersized preparations in the cortical bone should be made with connected concave abutments during primary or secondary surgery. Patients should receive supportive peri-implant therapy during maintenance.

CONCLUSIONS

MBL development is multifactorial and can be reduced by considering the biological, material, and technical factors.

Ionizing radiation effects on osseointegration: a pre-clinical study

The purpose of this study was to evaluate the effect of a single dose of ionizing radiation (30 Gy) on the osseointegration of implants in the rabbit tibia. Twenty rabbits received two dental Morse-tapered junction implants and one implant in each tibia. The animals were randomly divided into two groups (n=10), non-irradiated (NoIr) and irradiated (Ir), wherein the Ir group received a single dose of 30 Gy radiation 2 weeks after implant installation. Microtomographic analyses (BV/TV) and histomorphometric assessments (BIC and BABT) were performed 4 weeks after implant installation. One-way ANOVA, Tukey's test, and Student's t-test (α=0.05) were used for data analysis. The results showed that BV/TV did not differ significantly between the Ir and NoIr groups (P = 0.071). In the histomorphometric analysis, neither BIC nor BABT showed significant differences between the NoIr and Ir groups (p>0.05). In conclusion, ionizing radiation in dental implants does not appear to interfere with osseointegration when installed prior to irradiation.

Surface Topography Has Less Influence on Peri-Implantitis than Patient Factors: A Comparative Clinical Study of Two Dental Implant Systems

OBJECTIVES

This study aims to assess the risk of peri-implantitis (PI) onset among different implant systems and evaluate the severity of the disease from a population of patients treated in a university clinic. Furthermore, this study intends to thoroughly examine the surface properties of the implant systems that have been identified and investigated.

MATERIAL AND METHODS

Data from a total of six hundred and 14 patients were extracted from the Institute of Clinical Dentistry, Dental Faculty, University of Oslo. Subject- and implant-based variables were collected, including the type of implant, date of implant installation, medical records, recall appointments up to 2022, periodontal measurements, information on diabetes, smoking status, sex, and age. The outcome of interest was the diagnosis of PI, defined as the occurrence of bleeding on probing (BoP), peri-implant probing depth (PD) ≥ 5 mm, and bone loss (BL). Data were analyzed using multivariate linear and logistic regression. Scanning electron microscopy, light laser profilometer, and X-ray photoelectron spectroscopy were utilized for surface and chemical analyses.

RESULTS

Among the patients evaluated, 6.8% were diagnosed with PI. A comparison was made between two different implant systems: Dentsply Sirona, OsseospeedTM and Straumann SLActive, with mean follow-up times of 3.84 years (SE: 0.15) and 3.34 years (SE: 0.15), respectively. The surfaces have different topographies and surface chemistry. However, no significant association was found between PI and implant surface/system, including no difference in the onset or severity of the disease. Nonetheless, plaque control was associated with an increased risk of developing PI, along with the gender of the patient. Furthermore, patients suffering from PI exhibited increased BL in the anterior region.

CONCLUSION

No differences were observed among the evaluated implant systems, although the surfaces have different topography and chemistry. Factors that affected the risk of developing PI were plaque index and male gender. The severity of BL in patients with PI was more pronounced in the anterior region. Consequently, our findings show that success in implantology is less contingent on selecting implant systems and more on a better understanding of patient-specific risk factors, as well as on implementing biomaterials that can more effectively debride dental implants.

An introduction to dental implants

The use of implants to replace missing teeth is now commonplace and practised by clinicians worldwide in both general and specialist practice. There is an abundance of evidence on the general success of implant treatment. As well as reviewing the history of dental implants, this narrative review will discuss the merits and successful placement of tissue-level verses bone-level implants. Furthermore, the article will evaluate the concept and benefits of platform switching for implant treatment. Finally, with the increased placement of implants, this narrative paper will review how different titanium surfaces impact on the risk of peri-implantitis.

Maxillary Full Arch Restorations - Biological Complications: A Narrative Review Outlining Criteria for Long Term Success

PURPOSE

Patients receiving full arch implant borne maxillary prostheses require functional, esthetic, and long term success. The importance of this review is to document the difficulty with implant maintenance, the prevalence of peri-implant disease, and the improvement in biologic health when using a prosthesis that can be maintained to minimize plaque. The objective is to provide surgeons with a reference to optimize surgical procedures that can result in improved hygiene and long term maintenance, as well as acceptable functional and esthetic goals.

METHODS

Pubmed.gov was the information source. Years reviewed included 1990-2022. Inclusion criteria included only articles in journals referenced in pubmed.gov. The reports excluded were case reports, reports that only included implant survival, and articles without a statistical analysis to generate meaningful conclusions. Biological complications included bone loss, hygiene difficulty, mucositis and recession, the incidence of peri-implantitis, and how complications related to patient co-morbidities. Data collected included outcomes of the study including statistical significance.

RESULTS

The search identified articles for review using terms which included full arch maxillary restorations (n = 736), long term success with full arch maxillary prostheses (n = 22), ceramic full arch restorations (n = 102), and complications with full arch restorations (n = 231). From this search, 53 articles were collated that satisfied the inclusion criteria. Factors found to be significant contributors to biological complications included bone loss and peri-implant disease, difficulty with daily hygiene access, plaque and biofilm coverage, and the need for continued maintenance for long term implant health.

CONCLUSION

The surgeon needs to place implants to allow a full arch maxillary prosthesis to be fabricated with full access to the implants for maintenance, which should decrease the incidence of biological complications. With excellent maintenance full arch implant restorations can have limited peri-implant disease.

Single geometry abutment for narrow and extra-narrow implant systems: Survival and failure modes

The use of identical prosthetic components for all implant diameters could reduce the production costs by companies and the complexity of component selection for the clinician and his team. However, it would imply in reduction of thickness of the cervical walls of tapered internal connection implants, which could compromise the reliability of narrow and extra-narrow implants. Therefore, this study aims to evaluate the probability of survival and failure modes of extra-narrow implant systems with the same internal diameter as standard-diameter implants using the same prosthetic components. It was used eigth different implant system configurations, including narrow (Ø 3.3 mm) (N) extra-narrow (Ø 2.9 mm) (EN) and extra-narrow-scalloped (Ø 2.9 mm) (ENS) implants, both with cementable abutments (Ce) or titanium bases (Tib) and one-piece implants (Ø 2.5 mm and Ø 3.0 mm) (OP) (Medens, Itu, SP, Brazil), comprising the following groups: OP 3.0; OP 2.5; N Ce; N Tib; EN Ce, EN Tib, ENS-Ce and ENS-Tib. The implants were embedded using polymethylmethacrylate acrylic resin in a 15 mm matrix. Standardized maxillary central incisor crowns were virtually designed and milled to fit on the different studied abutments and cemented using a dual self-adhesive resin cement. The specimens were submitted to SSALT (Step Stress Accelerated Life Testing) at 15 Hz in water until failure or suspension of the test, until a maximum load of 500 N. Fractographic analysis of the failed specimens were realized in scanning electron microscopy. All implant systems demonstrated high probability of survival (90-100%) for missions at 50 and 100 N and values of characteristic strength superior to 139 N. Failure modes were restricted to the abutment in all the implant configurations tested. Therefore, the use extra-narrow implants with standardized prosthetic components for different implant diameters is a viable option for the replacement of anterior teeth.

Fracture and Fatigue of Dental Implants Fixtures and Abutments with a Novel Internal Connection Design: An In Vitro Pilot Study Comparing Three Different Dental Implant Systems

The aim of this study was to compare the mechanical behaviors of three dental implant fixtures with different abutment connection designs. Three implant systems were studied: the control (BLX implant), test group 1 (TORX++ implant), and test group 2 (IU implant). Three samples from each group were subjected to static compression to fracture tests to determine the maximum fracture load, and twelve samples were exposed to fatigue tests that measured how many cycles the implants could endure before deformation or fracture. Detailed images of the implant-abutment assemblies were obtained using micro-computed tomography imaging, and fractured or deformed areas were observed using a scanning electron microscope (SEM). The mean maximum breaking loads of 578.45 ± 42.46 N, 793.26 ± 57.43 N, and 862.30 ± 74.25 N were obtained for the BLX, TORX++, and IU implants, respectively. All samples in the three groups withstood 5 × 10⁶ cycles at 50% of the nominal peak value, and different fracture points were observed. All abutment connection designs showed suitable mechanical properties for intraoral use. Microscopic differences in the fracture patterns may be due to the differences in the fixture design or abutment connection, and mechanical complications could be prevented by lowering the overload reaching the implant or preventing peri-implantitis.

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.

Surface Structure of Zirconia Implants: An Integrative Review Comparing Clinical Results with Preclinical and In Vitro Data

Background: The purpose of this review was to analyze and correlate the findings for zirconia implants in clinical, preclinical and in vitro cell studies in relation to surface structure. Methods: Electronic searches were conducted to identify clinical, preclinical and in vitro cell studies on zirconia implant surfaces. The primary outcomes were mean bone loss (MBL) for clinical studies, bone-to-implant contact (BIC) and removal torque (RT) for preclinical studies and cell spreading, cell proliferation and gene expression for cell studies. The secondary outcomes included comparisons of data found for those surfaces that were investigated in all three study types. Results: From 986 screened titles, 40 studies were included for data extraction. In clinical studies, only micro-structured surfaces were investigated. The lowest MBL was reported for sandblasted and subsequently etched surfaces, followed by a sinter and slurry treatment and sandblasted surfaces. For BIC, no clear preference of one surface structure was observable, while RT was slightly higher for micro-structured than smooth surfaces. All cell studies showed that cell spreading and cytoskeletal formation were enhanced on smooth compared with micro-structured surfaces. Conclusions: No correlation was observed for the effect of surface structure of zirconia implants within the results of clinical, preclinical and in vitro cell studies, underlining the need for standardized procedures for human, animal and in vitro studies.

Latest Trends in Surface Modification for Dental Implantology: Innovative Developments and Analytical Applications

An increase in the world population and its life expectancy, as well as the ongoing concern about our physical appearance, have elevated the relevance of dental implantology in recent decades. Engineering strategies to improve the survival rate of dental implants have been widely investigated, focusing on implant material composition, geometry (usually guided to reduce stiffness), and interface surrounding tissues. Although efforts to develop different implant surface modifications are being applied in commercial dental prostheses today, the inclusion of surface coatings has gained special interest, as they can be tailored to efficiently enhance osseointegration, as well as to reduce bacterial-related infection, minimizing peri-implantitis appearance and its associated risks. The use of biomaterials to replace teeth has highlighted the need for the development of reliable analytical methods to assess the therapeutic benefits of implants. This literature review considers the state-of-the-art strategies for surface modification or coating and analytical methodologies for increasing the survival rate for teeth restoration.

Stimulation of dental implant osseointegration by low-Intensity pulsed ultrasound: An in vivo preliminary study in a porcine model

PURPOSES

Several studies have evaluated the interest of Low Intensity Pulsed Ultrasound (LIPUS) in the osseointegration of dental implants in murine or rabbit models. However, the thinness and narrowness bones make it difficult to study the effect of LIPUS. The purpose of this study is to assess the ability of LIPUS to stimulate bone formation in contact with a titanium dental implant in a porcine model.

METHODS

Eight adults mini-pigs were used. An implant is placed on each tibial crest in the metaphysis. The right side was treated with LIPUS at 1 MHz and 300 mW/cm² of acoustic intensity during 15 minutes per day on 5 consecutive days and during 42 days. The left side was not treated. The Bone Volume/Total Volume ratio (BV/TV), the Intersection Surface (IS) of the volume of interest by the binarized bone and the Trabecular bone Thickness (TbTh) around the implant were analyzed.

RESULTS

At 42 days, BV/TV ratio is significantly higher on the treated side (42,1+/-8,76% versus 32,31+/-10,11%, p < 0,02); as well as TbTh with 0,13+/-0,01 mm versus 0,10+/-0,01 mm (p < 0,01). IS is also significantly higher on the treated side (40,7 +/- 12,68 mm² versus 33,68+/-9,44 mm² at 200 μm from the implant surface; p < 0,01).

CONCLUSION

The present study showed that LIPUS can significantly increase bone formation and accelerate the healing process at the bone-implant interface in a porcine model. Its low toxicity, low immunogenicity and non-invasion make it a complementary treatment of choice for improving the bone formation around titanium implants.

Design and surface characterization of micropatterned silica coatings for zirconia dental implants

The use of zirconia as an alternative biomaterial for titanium implants has been increasing due to its biocompatibility, favorable aesthetic features, less potential for early plaque accumulation and mechanical properties. Despite the developed efforts, strategies to promote an effective osseointegration are still enough. In this sense and combining the silica properties to improve bone formation with the micropatterning guidance characteristics, silica coatings with micropatterns were designed and evaluated regarding their hydrophilicity and integrity through resistance to scratch and friction tests against femoral bone plates (simulating implant insertion). A combined sol-gel and soft-lithography techniques were used to produce silica coatings onto zirconia substrates and different techniques were used to characterize the micropatterned silica coatings. The results revealed that the production of lines and pillars micropatterns increases the surface roughness (Ra values) and improves the surface strength adhesion. Through the scratch test, it was possible to verify that the integrity and topography characteristics of all micropatterned coatings were not significantly affected after the friction test meaning that their function is not compromised after implant insertion. Additionally, the lines micropattern was the one that presented the highest hydrophilicity for distilled water, thus being a promising surface to promote improved osseointegration. The combined use of different surface micropatterns could potentially be used to guide bone apposition and avoiding peri-implantitis.

Expression of osteogenic markers after administration of selective estrogen receptor modulators during implant placement in the osteoporotic rat maxilla

PURPOSE

This study examined the effects of raloxifene during bone formation around the dental implant in the ovariectomy-induced osteoporotic rat maxilla.

METHODS

Fifty-four female 10-week-old Sprague-Dawley rats were divided into three groups (n = 18 each); sham-operated (control), ovariectomized (OVX), and ovariectomized and raloxifene-administered (RAL). Eight weeks after ovariectomy, both upper first molars were extracted, and implants were placed 4 weeks post-extraction. The RAL group was given 1 mg/kg of raloxifene per day while the other groups received a vehicle. Six rats in each group were sacrificed at days 4, 7, and 14 and submitted for quantitative reverse transcription polymerase chain reaction and immunohistochemical staining, for evaluation of osteogenic genes expressions.

RESULTS

The alkaline phosphatase expression was upregulated in the RAL group compared to the OVX group at day 4. The osteocalcin expression was significantly higher between the RAL group and the OVX group at day 7. Immunohistochemical staining revealed increased expression during the initial bone-forming process and indicated more active bone formation in the RAL group than in the OVX group.

CONCLUSION

Raloxifene administration enhanced the osteogenic genes and proteins expression in the bone around the implant. Further studies are required to establish the long-term clinical effects of raloxifene administration.

Microbiological and clinical evaluation of ultrasonic debridement with/without erythritol air polishing during supportive periodontal therapy in arches with full-arch fixed implant-supported prostheses: protocol for a randomised controlled trial

INTRODUCTION

Implant-supported prostheses are often successfully used in edentulous patients. However, the incidences of peri-implant mucositis and peri-implantitis increase over time. The accumulation of pathogenic bacteria adjacent to prostheses can induce peri-implant disease. Plaque removal is recommended to prevent and manage peri-implant diseases. The purpose of this study is to compare the plaque removal efficacy of ultrasonic debridement with/without erythritol air-polishing powder around implants and bridges in patients with full-arch fixed implant-supported prostheses as well as the effects of these two methods on the rates of peri-implant mucositis and peri-implantitis, and the submucosal microbiota composition over 5 years in patients undergoing supportive periodontal therapy.

METHODS AND ANALYSIS

We plan to enrol 10 edentulous (maxilla and/or mandible) patients seeking full-arch fixed implant-supported prostheses. The study will use a split-mouth model in which contralateral quadrants are randomly assigned to two groups. Group 1: one contralateral quadrant of full-arch fixed implant-supported prostheses will undergo ultrasonic debridement combined with erythritol air-polishing powder. Group 2: a separate contralateral quadrant of full-arch fixed implant-supported prostheses will undergo ultrasonic debridement. The 5-year trial will involve a total of 10 re-examinations per participant. The mucosal conditions around the implants will be recorded at 6-month intervals after restoration. Peri-implant submucosal plaque will be collected at each re-examination, and the bacterial flora will be analysed by 16s ribosomal RNA gene sequencing. X-ray examinations will be conducted at 12-month intervals to evaluate the marginal bone level around implants.

ETHICS AND DISSEMINATION

This prospective single-centre, randomised controlled trial (PKUSSIRB-202054045) has been approved by the Ethics Committee of Stomatology School and Hospital of Peking University. Data will be registered with the International Clinical Trials Registry Platform. Additionally, we will disseminate the results via publication in scientific journals.

TRIAL REGISTRATION NUMBER

ChiCTR-2000032431.

What is the influence of implant surface characteristics and/or implant material on the incidence and progression of peri-implantitis? A systematic literature review

OBJECTIVES

To answer the focused question, 'In animals or patients with dental implants, does implant surface characteristics and/or implant material have an effect on incidence and progression of peri-implantitis?'

MATERIAL AND METHODS

Pre-clinical in vivo experiments on experimental peri-implantitis and clinical trials with any aim and design, and ≥5 years follow-up, where the effect of ≥2 different type of implant material and/or surface characteristics on peri-implantitis incidence or severity, and/or progression, implant survival or losses due to peri-implantitis, and/or marginal bone levels/loss was assessed.

RESULTS

Meta-analyses based on data of pre-clinical experiments, using the ligature induced peri-implantitis model in the dog, indicated that after the spontaneous progression phase implants with a modified surface showed significantly greater radiographic bone loss (effect size 0.44 mm; 95%CI 0.10-0.79; p = .012; 8 publications) and area of infiltrated connective tissue (effect size 0.75 mm² ; 95%CI 0.15-1.34; p = .014; 5 publications) compared to non-modified surfaces. However, in 9 out of the 18 included experiments, reported in 25 publications, no significant differences were shown among the different implant surface types assessed. Clinical and/or radiographic data from 7605 patients with 26,188 implants, reported in 31 publications (20 RCTs, 3 CTs, 4 prospective cohort, and 4 retrospective studies; 12 with follow-up ≥10 years), overall did not show significant differences in the incidence of peri-implantitis, when this was reported or could be inferred, among the various implant surfaces. In general, high survival rates (90-100%) up to 30 years and no clinically relevant differences in marginal bone loss/levels, merely compatible with crestal remodelling, were presented for the various implant types.

CONCLUSION

Pre-clinical in vivo experiments indicate that surface characteristics of modified implants may have a significant negative impact on peri-implantitis progression, while clinical studies do not support the notion that there is a difference in peri-implantitis incidence among the various types of implant surfaces. No assumptions can be made regarding the possible impact of implant material on incidence and/or peri-implantitis progression due to limited information.

An open, randomised, multi-centre study, comparing straight and tapered apex implants design, in partially and totally edentulous maxillae

The design of the commercially available implant OsseoSpeed^® (control) was changed to a tapered apex with a smaller apical diameter; OsseoSpeed^® TX (test).

OBJECTIVE

The present study evaluated the clinical outcome of marginal bone level as primary outcome, and cumulative implant survival rate, primary stability and condition of the peri-implant mucosa as secondary outcomes, one year after loading.

MATERIAL AND METHODS

92 subjects (150 implants, ten centres), with partially or totally edentate maxillae were randomized to receive either test or control implants. One to six implants were placed in each subject using a one-stage surgical procedure. Subjects received a permanent prosthesis 10-12 weeks after implant placement and were followed for one year.

RESULTS

47 subjects in the test group received 82 implants and 45 subjects in the control group received 68 implants. Marginal bone level alterations from loading to 1-year follow-up was -0.02 × 0.41 mm (mean × SD) and -0.03 × 0.38 mm (mean × SD) for the test and the control group, respectively, indicating no difference between the groups. Non-inferiority was declared as confidence interval for the difference between control and test implants was no worse than 0.5 mm. The CSR was 98.8% in the test group and 100% in the control group, with no statistically significant difference between the groups.

CONCLUSIONS

Change of the apical design of a commercially available implant showed no significant effect on marginal bone level and CSR compared to the control implant. Missing data and many investigators may have influenced on the result. Trial registration number: NCT01324778.

Peri-implant bone-level changes in the second decade of loading with regard to the implant-abutment connection: a retrospective study on implants under systematic aftercare

BACKGROUND

This retrospective study investigates the change in the peri-implant bone level (PBL) during the 2nd decade of intraoral function in patients complying with a 'supportive implant therapy' (SIT) program. The results were statistically analyzed with respect to the implant abutment connection used.

METHODS

In a private practice, only patients with 20-year SIT compliance were identified. Of these, all patients with 10- and 20-year radiographs available were selected. Therefore, no control group was possible and implant losses had to be excluded. Two experienced researchers assessed the peri-implant bone levels. As three different abutment connection concepts (bone-level butt-joint, bone-level conical and tissue-level conical) and two different implant surfaces (machined vs. roughened) were involved, statistical analyses were performed to detect potential differences.

RESULTS

Ninety-three implants from 36 patients with 20-year SIT compliance and available radiographs were included in the study. At study baseline (10 years intraoral), a mean bone loss of - 1.7 mm (median - 1.2; standard deviation [sd] 1.4, range: 0 to - 7.2) was recorded. After 20 years, we found a mean bone loss of - 2.5 mm (median - 2.3, sd 1.79, range: - 0.5 to + 7.4). Furthermore, we found a mean bone loss of 0.8 mm in intraoral function from year 10 to year 20 (mean: 0.08 mm per year); this change was independent of the abutment connection type.

CONCLUSIONS

During the 2nd decade of function, peri-implant bone loss in patients with SIT compliance might be small in value and should not be expected in all implants.

Long-Term Clinical Behavior and Complications of Intentionally Tilted Dental Implants Compared with Straight Implants Supporting Fixed Restorations: A Systematic Review and Meta-Analysis

Simple Summary

Following tooth loosening due to periodontal disease, caries, trauma, or tumoral processes, bone resorption and remodeling of the alveolar ridge makes the insertion of implants difficult. A number of bone augmentation techniques are available to treat atrophic jaws. However, when posterior bone is lacking and extensive bone augmentation surgeries are rejected by the patient, placing distally tilted posterior implants may offer a valid therapeutic option for implant-supported restorations. This treatment modality places the implants in preexisting bone, improving bone anchorage and prosthetic support. Nevertheless, some studies suggest that for tilted implants, bending moments are greater at the level of the angled abutment.

Abstract

The aim of this study was to assess the long-term clinical behavior of straight implants in comparison with intentionally tilted dental implants (ITDI) supporting fixed restorations in partial or total edentulous arches, analyzing implant survival and success rates, complications, and marginal bone loss (MBL) after >5 years of function. An electronic search was conducted in five electronic databases (MEDLINE/Pubmed, Embase, Web of Science, Scopus, and Cochrane Central Register of Controlled Trials) supplemented by a manual search. The electronic and manual search identified 1853 articles, of which 8 articles were selected for analysis. Out of a total of 3987 dental implants, 2036 were axial dental implants and 1951 tilted. Similar results were found in implant survival or overall implant success rates. Moreover, no statistically significant differences were found in MBL (p = 0.369; MD 0.116 mm (−0.137; 0.369) 95% CI) The prosthodontic/biological complications reported in the articles were very diverse and irregularly distributed. This systematic review suggests that there is no difference between tilted compared with straight dental implants in the medium-long term (>5 years). However, further research is needed to generate long-term data and confirm the present review’s findings.

Early peri-implant bone loss as a predictor for peri-implantitis: A 10-year prospective cohort study

PURPOSE

To evaluate the effect of early bone loss (EBL), on long-term bone stability and future peri-implantitis development.

MATERIALS AND METHODS

Patients referred for implant placement between 2005 and 2009 were consecutively treated and followed for 10 years. After 10 years, patients were invited for a scientific diagnostic visit to evaluate implant survival and bone loss. Bone level changes were compared with baseline. Non-parametric testing was performed in cross-tabs (Pearson Chi-square and Fishers's exact test). Kaplan-Meier-estimated survival curves were plotted for different thresholds for EBL at different timepoints. Generalized linear mixed models with binomial distribution and logit link for peri-implantitis were fitted. An adjusted logistic mixed model was made to evaluate peri-implantitis, in relation with smoking status, history of periodontitis, and EBL > 0.5 mm.

RESULTS

Four hundred and seven patients (mean age of 64.86 years [range 28-92, SD 10.11]), with 1482 implants, responded to the 10-year recall invitation. After an average follow-up time of 10.66 years (range 10-14, SD 0.87), implant survival was 94.74%. Mean crestal bone loss after 10 years was 0.81 mm (SD 1.58, range 0.00-17.00). One hundred and seventy five implants in 76 patients had peri-implantitis (11.8% on implant level, 18.7% on patient level). EBL of 0.5, 1, and 2 mm were significant predictors for peri-implantitis and implant loss after 10 years. Implants with EBL ≥0.5 mm during the first year of function showed a 5.43 times higher odds for future peri-implantitis development. Probability in developing peri-implantitis was 52.06% when smoking, Periodontal history and EBL of >0.5 mm was combined.

CONCLUSION

The present study suggests that EBL is a predictor for long-term peri-implant pathology, with a significant higher risk for peri-implantitis when early bone loss exceeds the thresholds of 0.5 and 1 mm, especially when additional risk factors such as smoking or susceptibility for periodontal disease prior to implant treatment are present. Clinical trial registration number B670201524796.

Dimensional accuracy of vinyl polyether and polyvinyl siloxane impression materials in direct implant impression technique for multiple dental implants

Purpose:

The present study compared the dimensional accuracy of vinyl polyether silicone (VPES) and polyvinyl siloxane (PVS) impression materials used for non-splinted (NS) and splinted (S) direct open-tray impression techniques for multiple implants inserted in simulated edentulous mandibles.

Materials and methods:

A mandibular stainless steel model with eight internal connections for implant analogs was fabricated to simulate a clinical scenario. The acrylic resin splinted and non-splinted direct impressions were obtained for both VPES and PVS materials. Seventy-two cast samples were divided into four groups based on the impression techniques and materials used. The dimensional accuracies of the casts were measured in three different axes using a computerized coordinate measuring machine (CMM), and were statistically compared.

Results:

The differences in the distortion values between the VPES and PVS impression materials were not statistically significant. Similarly, the differences between the splinted and non-splinted groups among the VPES and PVS materials were not statistically significant.

Conclusion:

The casts fabricated from VPS or PVS impression materials provide similar dimensional accuracy regardless of the implant splinting method.

An evaluation of peri-implant marginal bone loss according to implant type, surgical technique and prosthetic rehabilitation: a retrospective multicentre and cross-sectional cohort study

To evaluate implant loss (IL) and marginal bone loss (MBL); follow-up period of up to 10 years after prosthetic loading. Retrospective multi-centre cross-sectional cohort study. Double analysis: (1) all the implants (n = 456) were analysed; (2) to allow for possible cluster error, one implant per patient (n = 143) was selected randomly. Statistical analysis: Spearman's correlation coefficient; Kruskal-Wallis (post-hoc U-Mann-Whitney); Chi-square (post-hoc Haberman). (1) Analysing all the implants (456): IL was observed in patients with past periodontitis (6 vs. 2.2%, p < 0.05), short implants (12 vs. 2.8%, p < 0.001) and when using regenerative surgery (11.3 vs. 2.9%, p < 0.001); greater MBL was observed among smokers (0.39 ± 0.52 vs. 0.2 ± 0.29, p < 0.01), maxillary implants (0.28 ± 0.37 vs. 0.1 ± 0.17, p < 0.0001), anterior region implants (0.32 ± 0.36 vs. 0.21 ± 0.33, p < 0.001), external connection implants (0.2 ± 0.29 vs. 0.63 ± 0.59, p < 0.0001), and 2-3 years after loading (p < 0.0001). (2) analysing the cluster (143): IL was observed in smokers (18.8 vs. 3.5%, p < 0.05), splinted fixed crowns (12.9%, p < 0.01), short implants (22.2 vs. 4.0%, p < 0.01) and when using regenerative surgery (19.2 vs. 3.4%, p < 0.01); greater MBL was observed in maxillary implants (0.25 ± 0.35 vs. 0.11 ± 0.18, p < 0.05), in the anterior region (p < 0.05), in the first 3 years (p < 0.01), in external connection implants (0.72 ± 0.71 vs. 0.19 ± 0.26, p < 0.01) and in short implants (0.38 ± 0.31 vs. 0.2 ± 0.32, p < 0.05). There is greater risk in smokers, patients with past periodontal disease, external connection implants, the use of short implants and when regenerative techniques are used. To prevent MBL and IL, implantologists should be very meticulous in indicating implants in patients affected by these host factors.

Prospective randomized clinical trial evaluating the effects of two different implant collar designs on peri-implant healing and functional osseointegration after 25 years

OBJECTIVES

Evaluate the effects of two different machined-collar lengths and designs on peri-implant healing.

MATERIAL AND METHODS

An implant with a microtextured surface and 3.6mm-long internal-connection machined collar was compared to two implants that had an identical 1.2mm-long external-connection machined collar, but one had the microtextured surface while the other's was machined. Participants received the three implants, with microgap at the crest, alternately at five sites between mental foramen, and a full-arch prosthesis. Peri-implant bone levels were measured after 23 to 26 years of function. Keratinized tissue height, plaque, probing depth, bleeding, and purulence were also evaluated. Descriptive and mixed models for repeated\measures analyses were used, with Bonferroni correction for pairwise comparisons.

RESULTS

Twenty-two participants (110 implants) were evaluated at the 25-year examination. Microtextured implants with the longer machined collar had significantly greater mean marginal bone loss (-1.77mm ± 0.18, mean ± SE) than machined (-0.85mm ± 0.18, p < .001) and microtextured (-1.00 ± 0.18mm, p < .001) implants with the shorter machined collar. Keratinized tissue height was greater for internal-connection (0.74mm ± 0.10) versus external-connection (0.51 ± 0.08, p =  0.01) microtextured implants. No differences were observed for plaque (p = 0.78), probing depth (p = 0.42), bleeding (p  = 0.07), and purulence (p = 1.00). Implant survival rate was 99%.

CONCLUSIONS

Implants with the 1.2mm machined collar limited bone loss to 1mm, while those with the longer machined collar showed > 1.5mm loss after 25 years of function with microgap at the crest. Internal-connection design and fixture surface microtexturing did not result in greater bone preservation. ClinicalTrials.gov Identifier: NCT03862482.

Treatment of Full and Partial Arches with Internal-Conical-Connection Dental Implants: Clinical Results after 5 Years of Follow-Up

The aim of the present investigation is to evaluate the implant therapy outcomes over a period of 5 years and to analyze several patient risk factors influencing the stability of the peri-implant tissues. Seventy-eight patients were consecutively treated between 2009 and 2017 and restored with implant-supported fixed prostheses. The following inclusion criteria were considered: partial or complete edentulism; residual bone volume of at least 3.3 mm in diameter and 8 mm in length; a favorable relationship between maxilla and mandible; at least a minimum 5 year follow-up for each implant included in the statistical analysis. Intraoral radiographs were taken at implant loading and every 12 months during the follow-up visits. They were subsequently stored on a personal computer and analyzed to determine the changes in bone level. Seventy-eight patients receiving 209 implants completed a minimum follow-up period of 5 years. One-hundred dental implants were inserted in the maxilla while 109 were placed in the mandible. Eleven (14.1%) out of 78 treated patients who received 29 (13.9%) dental implants were considered as drop-outs. On the whole, peri-implantitis was diagnosed in three implants. The average final pocket probing depth at implant level was 2.5 ± 1.2 mm. The average final bone loss after 5 years was 0.3 ± 0.4 mm, both at the mesial and distal aspect of the implant. The effects of the prosthesis type, sex and implant site did not statistically influence the marginal bone loss; on the contrary, a statistically significant difference regarding marginal bone loss was detected between smoker and non-smoker patients (p = 0.021). Implants with internal-conical abutment connection showed stable peri-implant bone levels at the medium-term follow-up. Nevertheless, further prospective long-term clinical studies are necessary to confirm these data.

Comparison of peri-implant submucosal microbiota in arches with zirconia or titanium implant-supported fixed complete dental prostheses: a study protocol for a randomized controlled trial

Background

The success rate of implant-supported prostheses for edentulous patients is relatively high. However, the incidence of biological complications, especially peri-implant mucositis and peri-implantitis, increases yearly after the placement of prostheses. The accumulation of pathogenic bacteria adjacent to a prosthesis is the main cause of biological complications. Titanium, one of the classical materials for implant-supported prostheses, performs well in terms of biocompatibility and ease of maintenance, but is still susceptible to biofilm formation. Zirconia, which has emerged as an appealing substitute, not only has comparable properties, but presents different surface properties that influence the adherence of oral bacteria. However, evidence of a direct effect on oral flora is limited. Therefore, the aim of the present study was to assess the effects of material properties on biofilm formation and composition.

Methods

The proposed study is designed as a 5-year randomized controlled trial. We plan to enroll 44 edentulous (mandible) patients seeking full-arch, fixed, implant-supported prostheses. The participants will be randomly allocated to one of two groups: group 1, in which the participants will receive zirconia frameworks with ceramic veneering, or group 2, in which the participants will receive titanium frameworks with acrylic resin veneering. Ten follow-up examinations will be completed by the end of this 5-year trial. Mucosal conditions around the implants will be recorded every 6 months after restoration. Peri-implant submucosal plaque will be collected at each reexamination, and bacteria flora analysis will be performed with 16S rRNA gene sequencing technology in order to compare differences in microbial diversity between groups. One week before each visit, periodontal maintenance will be arranged. Each participant will receive an X-ray examination every 12 months as a key index to evaluate the marginal bone level around the implants.

Discussion

The current study aims to explore the oral microbiology of patients following dental restoration with zirconia ceramic frameworks or titanium frameworks. The features of the microbiota and the mucosal condition around the two different materials will be evaluated and compared to determine whether zirconia is an appropriate material for fixed implant-supported prostheses for edentulous patients.

Trial registration

International Clinical Trials Registry Platform (ICTRP) ChiCTR2000029470. Registered on 2 February 2020. http://www.chictr.org.cn/searchproj.aspx?

Allergies to Titanium Dental Implants: What Do We Really Know about Them? A Scoping Review

The purpose of this scoping review was to describe the current state of knowledge and understanding of allergies to titanium dental implants. A scoping review was conducted following the Prisma Extension for Scoping Reviews checklist. An electronic search was performed in five databases complemented by manual and grey literature searches. Fifty-two relevant papers were included for final review. Titanium particles can be released from the surfaces of dental implants in a process called tribocorrosion, which may contribute to bone loss due to inflammatory reaction. Diverse mechanisms have been described that may trigger allergy to titanium, as well as the clinical signs that manifest as the allergy develops. Allergies to titanium are uncommon but represent a real possibility that should not be overlooked in patients requiring prosthodontic rehabilitation with dental implants. Allergy can trigger a range of symptoms. Patients who have already been diagnosed with allergies to other metals will be more predisposed to suffering an allergy to titanium. Further investigation is needed in order to measure the true scope of these allergies.

Marginal Bone Loss in Implants with External Connection versus Internal Conical Connection Prior to Prosthetic Loading. A Randomized Clinical Study

Introduction: The prosthetic connection of implants has been related to the loss of marginal bone. The aim of this study was to evaluate bone loss around external connection (EC) and internal conical connection (ICC) implants prior to prosthetic loading. Material and methods: A randomized clinical trial (RCT) was carried out, with a sample size of 93 implants (31 EC and 62 ICC) placed in 27 patients. Radiological controls were performed and stability was measured by resonance frequency analysis (RFA) on the day of placement, at 1 month and at 4 months after the placement. Results: Bone loss in EC implants was not statistically different than in ICC implants between the time of placement (T0) and the subsequent month (T1): (EC = 0.18 mm and ICC = 0.17 mm). Between one month (T1) and four months (T2): (EC = 0.39 mm and ICC = 0.19 mm) this difference was highly significant (p = 0.00). Bone loss between T0 and T2 was significantly lower in the ICC (EC = 0.57 mm and ICC = 0.36 mm), (p = 0.01). The overall success rate of the implants was 97.8%. The stability of the implants increased from 70.69 (T0) to 73.91 (T1) and 75.32 (T2). Conclusions: ICC showed less bone loss up to the time of prosthesis placement. Such bone loss did not have a significant impact on bone stability. Long term RCTs are needed to demonstrate whether this bone loss, which is more pronounced at the beginning in EC, tends to stabilize and equate to ICC.

Factors associated with the presence of peri-implant buccal soft tissue dehiscences: A case-control study

BACKGROUND

To identify factors associated with the presence of buccal soft tissue dehiscences (BSTD).

METHODS

This cross-sectional observational study assessed 52 cases (CAS) with a minimum of 24 months of loading, with the presence of a BSTD, defined as an exposure of the prosthetic abutment, the implant neck or the implant surface in the anterior maxillae or mandible (premolar-premolar) and 52 carefully selected controls (CON) matched for age and years in function, being the only difference between groups the BSTD. Clinical parameters and radiographic findings from periapical radiographs and Cone Beam Computed Tomographies (CBCT) were analyzed to assess their association with the occurrence of BSTD using a multivariate regression model.

RESULTS

The CAS had a mean keratinzed mucosa (KM) of 1.65 ± 1.31 mm, whereas in the CON KM was 3.27 ± 1.28 mm (P = 0.001). Probing depths were similar in both groups, whereas bleeding on probing and plaque scores were higher in the CAS (P = 0.001). Mean bone level scores in the CAS were 1.71 ± 1.04 mm, and 1.27 ± 1.01 mm in CON (P = 0.143). The first bone to implant contact at the buccal aspect was 4.85 ± 3.12 mm in CAS and 2.15 ± 3.44 mm in CON (P = 0.001). CAS were 1.48 ± 0.93 mm outside the alveolar envelope, whereas the CON were 0.46 ± 0.77 mm. Implants buccally positioned in the CBCT's were 34 times more likely to belong to the case group. The presence of >2 mm of KM at the time of evaluation, presence of adjacent natural teeth, cemented restorations and two-piece implants were protective factors.

CONCLUSION

The bucco-palatal implant position was the most relevant factor related to the presence of BSTD.

Complications of Fixed Full-Arch Implant-Supported Metal-Ceramic Prostheses

We aimed to assess the biological and mechanical-technical complications and survival rate of implants of full-arch metal-ceramic prostheses, during five years of follow-up. 558 implants (of three different brands) retaining 80 full-arch metal-ceramic prostheses were placed in 65 patients, all of whom were examined annually for biological and mechanical-technical complications during the five years of follow-up. Descriptive statistics and univariate logistic regression were calculated. The cumulative survival rate of the implants was 99.8%, and 98.8% prosthesis-based. Mucositis was the most frequent of the biological complications and peri-implantitis was recorded as 13.8% at restoration-level, 16.9% at patient level and 2.0% at implant level. An implant length greater than 10 mm was shown to be a protective factor against biological complications. The mechanical-technical complications were associated with implant diameter, abutment/implant connection and retention system. Loss of screw access filling was the most frequent prosthetic complication, followed by the fracture of the porcelain. Full-arch metal-ceramic prostheses show a high prevalence of implant and prosthesis survival, with few biological and mechanical-technical complications.

Does the prosthesis weight matter? 3D finite element analysis of a fixed implant-supported prosthesis at different weights and implant numbers

PURPOSE

This study evaluated the influence of prosthesis weight and number of implants on the bone tissue microstrain.

MATERIALS AND METHODS

Fifteen (15) fixed full-arch implant-supported prosthesis designs were created using a modeling software with different numbers of implants (4, 6, or 8) and prosthesis weights (10, 15, 20, 40, or 60 g). Each solid was imported to the computer aided engineering software and tetrahedral elements formed the mesh. The material properties were assigned to each solid with isotropic and homogeneous behavior. The friction coefficient was set as 0.3 between all the metallic interfaces, 0.65 for the cortical bone-implant interface, and 0.77 for the cancellous bone-implant interface. The standard earth gravity was defined along the Z-axis and the bone was fixed. The resulting equivalent strain was assumed as failure criteria.

RESULTS

The prosthesis weight was related to the bone strain. The more implants installed, the less the amount of strain generated in the bone. The most critical situation was the use of a 60 g prosthesis supported by 4 implants with the largest calculated magnitude of 39.9 mm/mm, thereby suggesting that there was no group able to induce bone remodeling simply due to the prosthesis weight.

CONCLUSION

Heavier prostheses under the effect of gravity force are related to more strain being generated around the implants. Installing more implants to support the prosthesis enables attenuating the effects observed in the bone. The simulated prostheses were not able to generate harmful values of peri-implant bone strain.

Clinical and patient-reported outcome of implant restorations with internal conical connection in daily dental practices: prospective observational multicenter trial with up to 7-year follow-up

Background

The interpretation of the results of randomized clinical trials is often questioned in relation with daily circumstances in practices. This prospective observational multicenter study was instigated to reflect the need for information in real-life situations with dental implants with internal conical implant-abutment connection (Conelog implant system). The implants were followed up at least 5-year post-loading; survival analysis (Kaplan-Meier), changes of soft tissue, and bone level over time, as well as patient satisfaction were evaluated.

Results

In total, 130 dental implants were placed in 94 patients (64 female, 30 male). Mean age of patients was 50.4 ± 13.7. At 5-year post-loading, 104 implants in 76 patients were available for evaluation. The cumulative implant survival rate was 96.6%. After an initial bone remodeling process post-surgery (bone loss of − 0.52 ± 0.55 mm), the bone level change remained clinically stable from loading to 5-year post-loading (− 0.09 ± 0.43 mm). Patient satisfaction surveyed by questionnaire (comfort, ability to chew and taste, esthetics, general satisfaction) steadily increased towards the end. At the last study follow-up, all the patients rated their general satisfaction as either very satisfied (87.5%) or satisfied (12.5%).

Conclusion

The study implants have shown to be highly effective with reliable peri-implant tissue stability over the 5 to 7 years of observation for both single tooth restorations and fixed partial dentures while used in standard conditions in daily dental practice. The results obtained are comparable with those obtained in controlled clinical trials.

The Long-Term Effect of Smoking on 10 Years' Survival and Success of Dental Implants: A Prospective Analysis of 453 Implants in a Non-University Setting

Background: The purpose of this study was to compare the survival and peri-implant bone loss of implants with a fluoride-modified surface in smokers and non-smokers. Material and Methods: All patients referred for implant treatment between November 2004 and 2007 were scrutinized. All implants were placed by the same surgeon (B.C.). The single inclusion criterion was a follow-up time of at least 10 years. Implant survival, health, and bone loss were evaluated by an external calibrated examiner (S.W.) during recall visits. Radiographs taken at recall visits were compared with the post-surgical ones. Implant success was based on two arbitrarily chosen success criteria for bone loss (≤1 mm and ≤2 mm bone loss after 10 years). Implant survival in smokers and non-smokers was compared using the log-rank test. Both non-parametric tests and fixed model analysis were used to assess bone loss in both groups. Results: A total of 453 implants in 121 patients were included for survival analysis, and 397 implants in 121 patients were included for peri-implant bone-loss analysis. After a mean follow-up time of 11.38 years (SD 0.78; range 10.00–13.65), 33 implants out of 453 initially placed had failed in 21 patients, giving an overall survival rate of 92.7% and 82.6% on the implant and patient level, respectively. Cumulative 10 years’ survival rate was 81% on the patient level and 91% on the implant level. The hazard of implant loss in the maxilla was 5.64 times higher in smokers compared to non-smokers (p = 0.003). The hazard of implant loss for implants of non-smokers was 2.92 times higher in the mandible compared to the maxilla (p = 0.01). The overall mean bone loss was 0.97 mm (SD 1.79, range 0–17) at the implant level and 0.90 mm (SD 1.39, range 0–7.85) at the patient level. Smokers lost significantly more bone compared to non-smokers in the maxilla (p = 0.024) but not in the mandible. Only the maxilla showed a significant difference in the probability of implant success between smokers and non-smokers (≤1 mm criterion p = 0.003, ≤2 mm criterion p = 0.007). Taking jaw into account, implants in smokers experienced a 2.6 higher risk of developing peri-implantitis compared to non-smokers (p = 0.053). Conclusion: Dental implants with a fluoride-modified surface provided a high 10 years’ survival with limited bone loss. Smokers were, however, more prone to peri-implant bone loss and experienced a higher rate of implant failure, especially in the upper jaw. The overall bone loss over time was significantly higher in smoking patients, which might be suggestive for a higher peri-implantitis risk. Hence, smoking cessation should be advised and maintained after implant placement from the perspective of peri-implant disease prevention.

Effect of Implant Platform Connection and Abutment Material on Removal Torque and Implant Hexagon Plastic Deformation

Objectives  The aim of this study was to evaluate the plastic deformation of the hexagonal connection, and the removal torque of the implant-abutment joint of two dental implants combined with internal or external hexagonal connection implants after mechanical cycling.

Materials and Methods  Twenty-four dental implants were used in the study. Half of the implants had internal hexagonal connections (IH; Titamax II Plus) and the other half had external hexagonal connections (EH; Titamax Ti Ex). Four groups of two types of dental implant abutments (titanium: Ti, UCLA II Plus and zirconia: Zr, fabricated by CAD/CAM; n = 6) were investigated. The abutments received a metallic crown and the settings were submitted to mechanical cycling (MC; 10 ⁶ cycles, axial load, 120N). The connection surface area was measured by scanning electron microscope (SEM) images. The removal torque was evaluated and the plastic deformation of the hexagonal surface of the implant was measured by comparing the images before and after MC.

Statistical Analysis  Paired- t test was used to analyze the data statistically at a significance level of α = 0.05.

Results  The torque values decreased for all groups after MC, and the hexagonal surface area decreased due to plastic deformation for IH and EH associated with Zr abutments.

Conclusions  Zirconia abutments showed the worst plastic deformation of the implant connection surface and torque loosening when associated with IH implant.

Achievements in the Topographic Design of Commercial Titanium Dental Implants: Towards Anti-Peri-Implantitis Surfaces

Titanium and its alloys constitute the gold standard materials for oral implantology in which their performance is mainly conditioned by their osseointegration capacity in the host's bone. We aim to provide an overview of the advances in surface modification of commercial dental implants analyzing and comparing the osseointegration capacity and the clinical outcome exhibited by different surfaces. Besides, the development of peri-implantitis constitutes one of the most common causes of implant loss due to bacteria colonization. Thus, a synergic response from industry and materials scientists is needed to provide reliable technical and commercial solutions to this issue. The second part of the review focuses on an update of the recent findings toward the development of new materials with osteogenic and antibacterial capacity that are most likely to be marketed, and their correlation with implant geometry, biomechanical behavior, biomaterials features, and clinical outcomes.

Does the implant-abutment interface interfere on marginal bone loss? A systematic review and meta-analysis

The objective of this systematic review was to compare the conical internal connection (IC) with the external hexagonal connection (EH) on the occurrence of marginal bone loss (ΔMBL). Different databases were used to carry out the selection of the elected studies. The studies were judged according to the risk of bias as "high", "low" and "unclear" risk. For the meta-analysis we included only studies that could extract the data of ΔMBL, survival rate (SR) and probing depth (PD). No statistically significant differences were found for ΔMBL data at one, three- and five-year survival rates between implant connections (p <0.05), however statistically significant differences were found for PD between EH and IC implants (1-year follow-up) -0.53 [95%CI -0.82 to -0.24, p = 0.0004]. This present systematic review demonstrated that there are no significant differences between IC and EH implants for both ΔMBL and SR at 1, 3 e 5 years after functional loading, although better PD values were observed for implants pertaining to the IC connections. Considering the high heterogeneity, more well-delineated, randomized clinical trials should be conducted.

Analysis of trends in implant therapy at a surgical specialty clinic: Patient pool, indications, surgical procedures, and rate of early failures-A 15-year retrospective analysis

OBJECTIVES

To evaluate the patient population over a 3-year period and to compare it to observations of the population at the same clinic over a period of 15 years.

MATERIAL AND METHODS

Records of patients receiving dental implants in the Department of Oral Surgery and Stomatology, University of Bern, between January 2014 and December 2016 were analyzed and then compared with data from patients treated between 2002 and 2004 and between 2008 and 2010. Patients were analyzed for demographics and for indications for therapy, as well as for presence or absence and type of complications. Inserted implants were analyzed for type, length, and diameter, as well as for the number and type of associated tissue regeneration procedures.

RESULTS

Analysis revealed a continuous linear increase in the average age of patients seeking implant treatment. The most common indication for implant therapy was a single-tooth gap (STG) (50.5%), followed by distal extension situations (22.3%) and extended edentulous gaps (20.5%). A total of 60.8% of implants placed needed some type of bone augmentation, and 83.5% of implants placed in the anterior maxilla required simultaneous augmentation. Staged guided bone regeneration (GBR) was only necessary in 7% of the cases. Implant failure rates remained low at 0.6%, with postoperative hematomas being the most common postoperative complication (13.4%).

CONCLUSIONS

The rising demand for dental implants continues as the patient population ages. Single-tooth gaps remained consistently the most common indication for implant therapy in recent years. Proper case selection and evidence-based surgical protocols are essential for high success rates.

Innovative method "DV-PIMS" technique and dental implant design for grafting injectable platelet-rich fibrin around the dental implant - Goat jaw cadaver study

Aims

Dental implants have revolutionized the treatment modality for replacing missing teeth. The ability of implants to osseointegrate with the bone leads to its success. The problem is sometimes there is inadequate bone available for implant. If hygiene is not maintained, biofilms of bacteria can be formed around the dental implant. One approach to this problem has been development of bioactive surgical additives. Platelet-rich fibrin (PRF) appears as an alternative. There are various techniques of using PRF. These techniques need skill and practice to use PRF.

Objective

To evaluate implant stability and flow of injectable PRF (i-PRF) of regular implant and modified innovative design implant.

Materials and Methods

Thirty goat jaw bones were selected. Implants were placed in mandibular posterior region. Fifteen implants were placed using regular dental implant system (Group A) on the left side of jaw bone. The other 15 implants were placed using modified dental implant (Group B) on the right side of jaw bone. The body of these implants at middle has drainage vents to drain/flow the i-PRF-like dye. The dye was injected through regular and modified implants (DV-PIMS technique). Then the stability was checked with the help of Periotest. Cross section was taken 3 cm away from dental implant at the angle of mandible, to check the flow of i-PRF/platelet-rich plasma (PRP)-like dye.

Results

Periotest evaluation showed a mean of 2.3 for implant Group B and a mean of 1.5 for implant Group A. The flow of i-PRF-like dye was seen in Group B, and Group A does not show any flow.

Conclusion

There are various techniques of using PRF. These techniques need skill and practice to use PRF. This (DV-PIMS) method aims to explain new implant design that disperses an i-PRF solution from inside out. The screw section of the new implant is made of a reservoir running vertically down inside. That reservoir is filled with (injectable) PRF, and then a cover screw is placed. The solution will begin to slowly diffuse out, through the vents in implant, keeping biofilms from forming or avoiding at the screw-bone interface and accelerate healing process.

Sandblasting reduces dental implant failure rate but not marginal bone level loss: A systematic review and meta-analysis

INTRODUCTION

Sandblasting is one of the oldest implant surface modifications to enhance osseointegration. Regarding its superiority over machined surface controversies still exist. Our objective was to compare implant failures (IF) and marginal bone level (MBL) changes between sandblasted and machined dental implants by a meta-analysis utilizing the available data. The PROSPERO registration number of the meta-analysis is CRD42018084190.

METHODS

The systematic search was performed in Cochrane, Embase and Pubmed. Inclusion criteria included participants with neither systemic diseases, nor excessive alcohol consumption, nor heavy smoking. We calculated pooled Risk Ratio (RRs) with confidence intervals of 95% (CIs) for dichotomous outcomes (implant failure) and weighted mean difference (WMD) CIs of 95% for continuous outcomes (marginal bone level change). We applied the random effect model with DerSimonian-Laird estimation. I2 and chi2 tests were used to quantify statistical heterogeneity and gain probability-values, respectively.

RESULTS

Literature search revealed 130 records without duplicates. Out of these, seven studies met the inclusion criteria and all were included in data synthesis, involving 362 sand-blasted and 360 machined implants. The results indicate that there is an 80% (RR = 0.2 95% CI:0.06-0.67; I2 = 0.0% p = 0.986) lower among sandblasted compared to machined implants after one year of use and 74% (RR = 0.26 95% CI:0.09-0.74; I2 = 0.0% p = 0.968) five years of use, respectively. In contrast, there is no significant difference in MBL (WMD:-0.10mm, 95% CI:-0.20, 0.01; p>0.05; I2 = 0.0%, p = 0.560 and WMD:-0.01mm, 95% CI:-0.12, 0.09; p>0.05; I2 = 26.2%, p = 0.258) between the two implant surfaces after one and five years of use.

CONCLUSIONS

This meta-analysis reveals that sandblasting is superior over machined surface in implant failure but not in marginal bone level in healthy subjects. It also points out the need for further randomized clinical trials with large sample size for objective determination of the clinical benefits of certain implant surface modifications.

Prevalence of Peri-Implantitis in Implants with Turned and Rough Surfaces: a Systematic Review

Objectives

Moderately-rough implant surface may improve implant therapy in terms of bone integration, but the increased surface roughness might affect the initiation and development of peri-implantitis. The aim of the present review was to compare the prevalence of peri-implantitis in implants with rough and turned (machined) implant surfaces.

Material and Methods

An electronic literature search was conducted of the MEDLINE and EMBASE databases for articles published between 1 January 1990 and 1 March 2018. Clinical human studies in the English language that had reported on prevalence of peri-implantitis in tuned and rough surface implants were searched. The initial search resulted in 690 articles.

Results

Eight articles with 2992 implants were included in the systematic review. The incidence of peri-implantitis for two implant surfaces varied between studies. A meta-analysis was not feasible due to the heterogeneity among studies. Implant with rough surfaces were more favourable for plaque accumulation during short-term follow-up. On a long-term, turned implants surfaces were associated with more plaque and higher peri-implant bone loss. Peri-implant clinical parameters and survival rate for two implant surfaces was similar.

Conclusions

Within the limitations of the present study, rough implant surface does not seem to increase the incidence of peri-implantitis in comparison to turned implants surface.

The influence of prosthetic material on implant and prosthetic survival of implant-supported fixed complete dentures: a systematic review and meta-analysis

PURPOSE

Evaluating the impact of the prosthetic material on implant- and prosthetic survival of implant-supported fixed complete dentures.

STUDY SELECTION

Electronic and hand searches were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to identify clinical studies including at least 10 patients restored with implant-supported dentures. The primary outcome was to evaluate the implant survival rate according to the applied restorative materials. The prosthetic survival rate was evaluated as secondary outcomes.

RESULTS

Forty-one of 2254 studies were finally selected. A statistically significant difference (p = 0.0337) was found between implant survival rates in the main restorative groups (metal-ceramic:97%(95%CI [0.96;0.98]), all-ceramic:99%(95%CI [0.98;1.00]), metal-resin:97%(95%CI [0.96;0.98])). Prosthetic survival rates were: (metal-ceramic:95%(95%CI [0.89;0.97]), all-ceramic:97%(95%CI [0.92;0.99]), metal-resin:97%(95%CI [0.95;0.98]), with no statistically significant difference (p = 0.3796) between the groups. Chipping incidence rates were as follows: metal-ceramic:8%(95%CI[0.03;0.20]), all-ceramic:15%(95%CI [0.06;0.32]), and metal-resin:22%(95%CI [0.13;0.33]). Five types of exact restorative materials were identified (porcelain-fused-to-non-precious alloy, porcelain-fused-to-zirconia, precious-metal-acrylic-resin, non-precious-metal-acrylic resin, and PMMA). Again, implant survival rates were statistically significantly influenced by the applied restorative materials (p = 0.0126), whereas, no significant differences were reported regarding prosthetic survival rate.

CONCLUSIONS

Prosthetic material selection seems to have no clinically relevant influence on implant- and prosthetic survival rate in implant-supported fixed complete dentures. Due to the high chipping rate, quantifying prosthetic survival alone does not seem to be a reliable tool for evaluating the outcome of the restorations and providing recommendations. These results, along with the obvious lack of evidence, suggest that clinicians must exercise caution whenever porcelain-fused-to-zirconia or metal-resin restorations are considered.

Implant supported cantilevered fixed dental rehabilitations in partially edentulous patients: Systematic review of the literature. Part I

OBJECTIVES

To investigate in which clinical situations a cantilever fixed implant supported restorations can be a treatment alternative and which complications are reported.

MATERIALS AND METHODS

Two operators screened the literature (MEDLINE, EMBASE) and performed a hand search on the main journals dealing with implantology and prosthetics until 31 December 2017. Only articles that considered cantilever implant fixed restorations with at least 10 patients and with a mean follow-up of at least 5 year were selected. The outcome variables were survival of implants and prosthesis, mechanical, technical and biological complications, marginal bone loss. The review was performed according to the PRISMA statements. Risk of bias assessment was evaluated. Failure and complication rates were analysed using random effect Poisson regression models to obtain summary estimate of 5- and 10-year survival and complication rates.

RESULTS

A total of nine papers were selected for partially edentulous patients and reported high survival rate of the prosthesis. The estimated survival rate for 5-10 years was calculated to be 98.4% for the implants and 99.2% for the rehabilitations. Mechanical, technical and biological complications were reported with a cumulative 5-10 years complication rate of 28.66% and 26.57% for the patients and for the prosthesis, respectively. Two papers for single implant supporting 2-unit cantilever were not sufficient to draw conclusions.

CONCLUSIONS

There is evidence that cantilever can be successful treatment in partially edentulous patients. In two adjacent edentulous sites, data are not yet sufficient.

How do peri-implant biologic parameters correspond with implant survival and peri-implantitis? A critical review

Objectives

The aim of this critical review was to evaluate whether commonly used biologic diagnostic parameters correspond to implant survival and peri‐implantitis prevalence.

Materials and methods

Publications from 2011 to 2017 were selected by an electronic search using the Pubmed database of the US National Library of Medicine. Prospective and retrospective studies with a mean follow‐up time of at least 5 years and reporting prevalence of peri‐implantitis as well as mean bone loss and standard deviation were selected. The correlation between reported prevalence of peri‐implantitis and reported implant survival, mean follow‐up time, mean bone loss, mean probing depth, and mean bleeding on probing was calculated. Mean bone loss and standard deviation were used for estimation of proportion of implants with bone loss exceeding 1, 2, and 3 mm.

Results

Full‐text analysis was performed for 255 papers from 4,173 available ones, and 41 met all the inclusion criteria. The overall mean weighted survival rate was 96.9% (89.9%–100%) and the reported prevalence of peri‐implantitis ranged between 0% and 39.7%, based on 15 different case definitions. The overall weighted bone loss was 1.1 mm based on 8,182 implants and an average mean loading time ranging from 5 to 20 years. No correlation was found between mean bone loss and the reported prevalence of peri‐implantitis. The estimated prevalence of implants with bone loss above 2 mm was 23%. The overall weighted mean probing depth was 3.3 mm, and mean weighted bleeding was 52.2%. Only a weak correlation was found between survival and function time (r = −0.49). There was no relation between the probing depth or bleeding and the mean bone loss, mean follow‐up time, and reported prevalence of peri‐implantitis.

Conclusion

Biologic parameters mean probing depth and mean bleeding on probing do not correlate with mean bone loss and this irrespective of follow‐up. Case definition for peri‐implantitis varied significantly between studies indicating that an unambiguous definition based on a specified threshold for bone loss is not agreed upon in the literature.

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.

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 dental implants with different collar design and surface modifications: A systematic review on survival rates and marginal bone levels

AIM

The aim of this study was to compare clinical and radiographic outcomes of dental implants with different neck characteristics.

METHODS

A protocol-oriented search aimed at the question: "In patients subjected to tooth replacement with screw-type dental implants does the modification of the implant neck macro- or microgeometry contribute to the improvement of survival rates and maintenance of the peri-implant marginal bone levels?" Primary outcomes were survival and marginal bone level (MBL) changes evaluated on randomized controlled trials with >10 participants and follow-up >1 year. Risk of bias was evaluated using the Cochrane Collaboration's tool. The review follows the PRISMA statement.

RESULTS

Forty-three studies compared: (a) One- versus two-piece implants (N = 7); (b) Two-piece implants with different neck characteristics (machined and rough collars, microthreads, LASER microtexturing) (N = 21); (c) Two-piece implants with macrogeometry modifications (tapering, back-tapering, and scalloping) (N = 6). One- and two-piece implants showed similar survival (RR = 0.45, 95% CI: [0.12, 1.66], p = 0.23) and MBL changes (WMD = 0.09 mm, 95% CI: [-0.27, 0.45], p = 0.64) at 1-year post-loading. Machined collar implants have higher risk of early failure than rough collar implants (RR = 3.96, 95% CI: [1.12, 13.93], p = 0.03) and 0.43 mm higher bone resorption (95% CI: [0.0, 0.86], p = 0.05). Microthreads (WMD = 0.07 mm, 95% CI: [-0.01, 0.15], p = 0.10) and LASER microtexturing (WMD = 0.15 mm, 95% CI: [-0.35, 0.65], p = 0.56) do not reduce bone resorption. Scalloped implants have 1.26 mm higher resorption (95% CI: [0.72, 2.00], p < 0.001).

CONCLUSIONS

One- and two-piece implants have similar survival and MBL changes. Rough collar implants have lower MBL changes than machined collar implants. Additional modifications to rough collars are irrelevant.

Optimal number of implants for complete-arch implant-supported prostheses with a follow-up of at least 5 years: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Consensus is lacking regarding the optimal number of implants for supporting complete-arch prostheses with good survival rates and lower prosthetic complications and marginal bone loss.

PURPOSE

The purpose of this systematic review was to evaluate the influence of the number of implants used for complete-arch prostheses with at least 5 years of follow-up.

MATERIAL AND METHODS

A search was performed in the PubMed/MEDLINE, Scopus, and Cochrane Library databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria and was registered in The International Prospective Register of Systematic Reviews (CRD42016048468). The following was the population, intervention, comparison, outcome (PICO) question: Does the number of implants influence the longevity of complete-arch prostheses?

RESULTS

Nineteen studies including 1006 patients with a mean age of 61.44 years were selected for evaluation. The number of implants per jaw ranged between 2 and 9 in the maxilla, mandible, or both jaws. For implant survival rate in complete-arch prostheses with fewer than 5 implants per jaw, the pooled weighted event rate was 1.4% (I²=25.26%; P=.211) and 4.2% (I²=81.35%; P<.001) for complete arches with more than 4 implants per jaw. For the prosthesis survival rate, the pooled weighted event rate for a complete-arch with fewer than 5 implants per jaw was 1.5% (I²=0%; P=.677) and 9% (I²=17.33%; P=.304) for complete arches with more than 4 implants per jaw. For prosthesis complications for complete arches with fewer than 5 implants per jaw, the pooled weighted event rate was 19.9% (I²=93.5%; P<.001) and 24.5% (I²=88.89; P<.001) for complete arches with more than 4 implants per jaw. The mean marginal bone loss for complete arches with fewer than 5 implants per jaw was 1.22 ±0.49 mm (I²=99.46; P<.001) and 1.46 ±0.46 mm (I²=99.6; P <.001) for more than 4 implants per jaw.

CONCLUSIONS

The current systematic review indicated no relationship of the number of implants used to support a complete-arch prosthesis with implant survival rate, prosthesis survival rate, prosthesis complications, or marginal bone loss in studies with follow-up periods of between 5 and 15 years.

Ten-year survival of immediate-loading implants in fully edentulous mandibles in the Japanese population: a multilevel analysis

PURPOSE

To evaluate the long-term clinical results of and risk factors for immediate-loading implant treatment of completely edentulous mandibles.

METHODS

We retrospectively studied 220 implants in 52 patients who received immediate-loading implants in fully edentulous mandibles. Kaplan-Meier survival analyses, log-rank tests, and multilevel mixed-effects parametric survival analysis was used for statistical analyses.

RESULTS

Thirteen of implants in seven patients failed, and the 10-year cumulative implant survival rate was 93.9 % and significantly (p=0.049) higher in women than in men. None of the predictor variables were significantly associated with implant survival, although sex tended to be associated with implant survival.

CONCLUSIONS

Immediate-loading implant treatment for completely edentulous mandibles had acceptable clinical results in the long term. Although we could not identify significant risk factors, we established a multilevel mixed-effects parametric survival analysis with the immediate-loading implant survival data.