Implant-Supported Immediately Loaded Fixed Full-Arch Dentures: Evaluation of Implant Survival Rates in a Case Cohort of up to 7 Years

A Retrospective Evaluation of 5 Years of Clinical Results of Metal-Ceramic vs. Monolithic Zirconia Superstructures in Maxillary All-on-4TM Concept

The aim of the current study was to present the clinical and radiological outcomes of monolithic zirconia superstructures compared to the metal-ceramic ones in the All-on-4 concept for the prosthetic rehabilitation of the maxillae. A total of 30 patients were subdivided into groups according to their superstructure type (metal-ceramic (n = 15) or monolithic zirconia (n = 15)). All implants were functionally loaded within 24 h after insertion with provisional acrylic superstructures. Prosthetic complications, marginal bone loss, plaque accumulation, probing pocket depth, bleeding on probing, and bite force were documented over a period of 5 years. Marginal bone loss around the implants of the ceramic group remained well over the five years (1.21 ± 0.23 mm). However, marginal bone loss was significantly lower around the implants in the monolithic zirconia group (0.22 ± 0.14 mm) (p < 0.001). Bleeding on probing, plaque accumulation, and probing pocket depth values were correlated with marginal bone loss. Among all evaluated parameters, no differences could be detected in terms of the angulation of the implants. Detachment or chipping was observed in seven cases in the metal-ceramic superstructure group. In all cases, dentures were removed and repaired in the laboratory. In the monolithic zirconia group, chipping was detected after one year in two cases, after two years in four cases, and after five years in one case and could be managed by polishing in situ. Monolithic zirconia superstructures presented superior results regarding the parameters evaluated.

Critical evaluation of YouTube videos regarding the all-on-4 dental implant treatment concept: A content-quality analysis

STATEMENT OF PROBLEM

Rehabilitation of complete edentulous arches by using the all-on-4 dental implant treatment concept is a well-established procedure. Considering the popularity of YouTube as a source for health-related information, a thorough investigation of the content-quality and reliability of videos regarding the all-on-4 concept is lacking.

PURPOSE

The purpose of this cross-sectional analysis was to critically appraise the content-quality and reliability of YouTube videos regarding the all-on-4 dental implant treatment concept as a source of information for patients, students, and dentists.

MATERIAL AND METHODS

A comprehensive search was performed on the YouTube website using the specific keyword "All-on-4," which was identified as the most appropriate search term by the Google Trends website. Only English language videos regarding the all-on-4 dental implant treatment concept were included for systematic analyses. Following the eligibility criteria, the included videos were assessed for their demographic characteristics and quality-content. Based on the content score, the videos were categorized as low content (LC) and moderate + high content (MHC) groups. Further, qualitative analyses were performed by using the DISCERN tool and a global quality (GQ) scale. Statistical analyses were conducted by using the Mann-Whitney U test and the Spearman correlation analysis (α=.05).

RESULTS

Of 250 screened videos, only 73 were eligible for final analyses. The included videos presented an average 123 846 (range, 4 to 3 182 404) views with a mean duration of 528 (range, 12 to 1699) seconds. In addition, the average number of likes was 1122 (range, 0 to 3300), but, remarkably, none of the included videos received any dislikes. Overall, the mean content-quality score was 6.2 ±3.8, thus indicating low-quality content. The average DISCERN and GQ scores were 47.73 ±9.94 and 3.41 ±0.95, with the Spearman rank correlation test showing a strong positive correlation (r=.732; P<.001) among the total obtained scores. Moreover, statistically significant differences were reported between the LC and MHC groups for both DISCERN and GQ scores (P<.001).

CONCLUSIONS

The reliability of YouTube videos regarding the all-on-4 dental implant treatment concept is questionable, as they exhibit poor content-quality, thus making them an unreliable source for patients, students, and dentists seeking accurate information.

Mesenchymal stem cells and dental implant osseointegration during aging: from mechanisms to therapy

Dental implants are widely used to replace missing teeth, providing patients with unparalleled levels of effectiveness, convenience, and affordability. The biological basis for the clinical success of dental implants is osseointegration. Bone aging is a high-risk factor for the reduced osseointegration and survival rates of dental implants. In aged individuals, mesenchymal stem cells (MSCs) in the bone marrow show imbalanced differentiation with a reduction in osteogenesis and an increase in adipogenesis. This leads to impaired osseointegration and implant failure. This review focuses on the molecular mechanisms underlying the dysfunctional differentiation of aged MSCs, which primarily include autophagy, transcription factors, extracellular vesicle secretion, signaling pathways, epigenetic modifications, microRNAs, and oxidative stress. Furthermore, this review addresses the pathological changes in MSCs that affect osseointegration and discusses potential therapeutic interventions to enhance osseointegration by manipulating the mechanisms underlying MSC aging.

The All-on-four concept for fixed full-arch rehabilitation of the edentulous maxilla and mandible: a longitudinal study in Japanese patients with 3-17-year follow-up and analysis of risk factors for survival rate

PURPOSE

Implant-supported immediately loaded fixed full-arch rehabilitation via All-on-four treatment yields good long-term results for both the maxilla and the mandible. However, the risk factors affecting long-term implant survival are unknown, and the long-term prognosis of All-on-four concept procedures in Japanese individuals has not been elucidated. We aimed to determine the cumulative implant survival rate after 3-17-year follow-up and identify the associated risk factors.

METHODS

We analysed 561 cases (307 maxillae, 254 mandibles) with 2364 implants (1324 maxillae, 1040 mandibles) that received All-on-four treatment. We investigated the cumulative implant- and patient-level survival rates and various risk factors for implant failure. Statistical analysis was performed using the log-rank test for differences in Kaplan-Meier curves, univariate analysis using the Chi-square test, and multivariate analysis for risk factors affecting the survival rate.

RESULTS

The cumulative survival rate was 94.4% by patient level and 97.4% by implant level for the maxilla, and 96.7% by patient level and 98.9% by implant for the mandible, with up to 17 years of follow-up. The maxillary survival rate at the implant level was significantly lower (p < 0.05). Furthermore, the maxillary survival rate within 24 months was significantly lower at the implant level (p < 0.01). Multivariate analysis revealed that the maxilla was the most significant risk factor (p < 0.01).

CONCLUSIONS

All-on-four treatment yielded high long-term survival rates in Japanese patients. However, the maxilla showed a significantly lower cumulative survival rate than the mandible, while early failure was significantly higher. Furthermore, the maxilla was a significant risk factor influencing the survival rate.

The oral microbiome of implant-abutment screw holes compared with the peri-implant sulcus and natural supragingival plaque in healthy individuals

PURPOSE

An implant-supported prosthesis consists of an implant fixture, an abutment, an internal screw that connects the abutment to the implant fixture, and the upper prosthesis. Numerous studies have investigated the microorganisms present on the implant surface, surrounding tissues, and the subgingival microflora associated with peri-implantitis. However, there is limited information regarding the microbiome within the internal screw space. In this study, microbial samples were collected from the supragingival surfaces of natural teeth, the peri-implant sulcus, and the implant-abutment screw hole, in order to characterize the microbiome of the internal screw space in healthy subjects.

METHODS

Samples were obtained from the supragingival region of natural teeth, the peri-implant sulcus, and the implant screw hole in 20 healthy subjects. DNA was extracted, and the V3-V4 region of the 16S ribosomal RNA was sequenced for microbiome analysis. Alpha diversity, beta diversity, linear discriminant analysis effect size (LEfSe), and network analysis were employed to compare the characteristics of the microbiomes.

RESULTS

We observed significant differences in beta diversity among the samples. Upon analyzing the significant taxa using LEfSe, the microbial composition of the implant-abutment screw hole's microbiome was found to be similar to that of the other sampling sites' microbiomes. Moreover, the microbiome network analysis revealed a unique network complexity in samples obtained from the implant screw hole compared to those from the other sampling sites.

CONCLUSIONS

The bacterial composition of the biofilm collected from the implant-abutment screw hole exhibited significant differences compared to the supra-structure of the implant. Therefore, long-term monitoring and management of not only the peri-implant tissue but also the implant screw are necessary.

Avoiding implant-related complications in medically compromised patients with or without unhealthy lifestyle/Elevated oxidative stress

Increased human life expectancy broadens the alternatives for missing teeth and played a role in the widespread use of dental implants and related augmentation procedures for the aging population. Though, many of these patients may have one or more diseases. These systemic conditions may directly lead to surgical complications, compromise implant/bone healing, or influence long-term peri-implant health and its response to biologic nuisances. Offering patients credible expectations regarding intra- and postoperative complications and therapeutic prognosis is an ethical and legal obligation. Clear identification of potential types of adverse effects, complications, or errors is important for decision-making processes as they may be related to different local, systemic, and technical aspects. Therefore, the present review structures the underlying biological mechanisms, clinical evidence, and clinical recommendations for the most common systemic risk factors for implant-related complications.

Study on Overdenture of Immediate Implant Placement and Function

OBJECTIVE

This study aims to investigate the bone remodelling and resorption in immediate implantation and restoration of clinical implant-supported overdentures.

MATERIALS AND METHODS

Six adult domestic dogs were divided into 2 groups: In the experimental group, 6 implants were immediately placed in each mandible, the distal end implants were inclined distal to the long axis of the tooth at an angle of 30 degrees, and restored immediately. As the control group, the animals underwent immediate implant placement with single denture restoration, respectively, nontilting and tilting at 30 degrees in the long axis of the tooth. The osseointegration index (OI) and rate of bone ingrowth fraction were measured, and the peri-implant bone remodelling was observed. The marginal bone loss was measured in the slices of bone-implant and analyzed.

RESULTS

New bone regenerated and had remodelled in each group. The experimental group had no statistically significant differences, when compared with other groups, except the tilted implant control group, in terms of the OI and bone ingrowth fraction.

CONCLUSION

Obvious bone absorption did not statistically significantly occur in implant-supported overdenture of immediate implant placement and function with satisfactory new bone and OI.

Marginal Bone Level and Biomechanical Behavior of Titanium-Indexed Abutment Base of Conical Connection Used for Single Ceramic Crowns on Morse-Taper Implant: A Clinical Retrospective Study

The goal of this retrospective clinical study was to evaluate the behavior of Morse-taper indexed abutments by analyzing the marginal bone level (MBL) after at least 12 months of function. Patients rehabilitated with single ceramic crowns between May 2015 and December 2020 received single Morse-taper connection implants (DuoCone implant) with two-piece straight abutment baseT used for at least 12 months, presenting periapical radiograph immediately after crown installation were enrolled. The position of the rehabilitated tooth and arch (maxilla or mandible), crown installation period, implant dimensions, abutment transmucosal height, installation site (immediate implant placement or healed area), associated with bone regeneration, immediate provisionalization, and complications after installation of the final crown were analyzed. The initial and final MBL was evaluated by comparing the initial and final X-rays. The level of significance was α = 0.05. Seventy-five patients (49 women and 26 men) enrolled had a mean period of evaluation of 22.7 ± 6.2 months. Thirty-one implant-abutment (IA) sets had between 12–18 months, 34 between 19–24 months, and 44 between 25–33 months. Only one patient failed due to an abutment fracture after 25 months of function. Fifty-eight implants were placed in the maxilla (53.2%) and 51 in the mandible (46.8%). Seventy-four implants were installed in healed sites (67.9%), and 35 were in fresh socket sites (32.1%). Thirty-two out of these 35 implants placed in fresh sockets had the gap filled with bone graft particles. Twenty-six implants received immediate provisionalization. The average MBL was −0.67 ± 0.65 mm in mesial and −0.70 ± 0.63 mm in distal (p = 0.5072). The most important finding was the statistically significant difference comparing the values obtained for MBL between the abutments with different transmucosal height portions, which were better for abutments with heights greater than 2.5 mm. Regarding the abutments’ diameter, 58 had 3.5 mm (53.2%) and 51 had 4.5 mm (46.8%). There was no statistical difference between them, with the following means and standard deviation, respectively, −0.57 ± 0.53 mm (mesial) and −0.66 ± 0.50 mm (distal), and −0.78 ± 0.75 mm (mesial) and −0.746 ± 0.76 mm (distal). Regarding the implant dimensions, 24 implants were 3.5 mm (22%), and 85 implants (78%) had 4.0 mm. In length, 51 implants had 9 mm (46.8%), 25 had 11 mm (22.9%), and 33 implants were 13 mm (30.3%). There was no statistical difference between the abutment diameters (p > 0.05). Within the limitations of this study, it was possible to conclude that better behavior and lesser marginal bone loss were observed when using abutment heights greater than 2.5 mm of transmucosal portion and when placed implants with 13 mm length. Furthermore, this type of abutment showed a little incidence of failures within the period analyzed in our study.

Immediate loaded fixed complete dentures supported by implants in patients with a history of periodontitis: A retrospective cohort study of 2 to 7 years

STATEMENT OF PROBLEM

The outcome of implant-supported fixed complete dentures in edentulous patients with a history of periodontitis is unclear.

PURPOSE

The purpose of this retrospective clinical study was to assess the clinical outcomes of immediate loaded fixed complete dentures in individuals with a history of periodontitis and to analyze risk factors related to implant failure.

MATERIAL AND METHODS

A total of 642 implants (146 prostheses) in 119 patients were included. The follow-up period ranged from 2 to 7 years. Implant survival rates, marginal bone loss, mechanical complications, biologic complications, and patient satisfaction were evaluated. The Pearson chi-square test, independent samples t test, and multivariate generalized estimating equation were performed for statistical analysis (α=.05).

RESULTS

Eleven implants in 9 patients failed, leading to overall survival rates of 98.3% at the implant level and 92.4% at the patient level. The mean ±standard deviation marginal bone loss was 0.62 ±0.86 mm, and marginal bone loss did not differ significantly between axial and tilted implants (P>.05). Mechanical complications were detected in 55 (37.7%) definitive prostheses; biologic complications were detected in 318 (49.5%) implants. Smokers had a significantly lower survival rate than nonsmokers (odds ratio: 6.880, P=.013). Bruxers had a significantly higher incidence of mechanical complications than nonbruxers (P<.001).

CONCLUSIONS

The immediate loaded fixed complete denture supported by implants is a suitable treatment option for edentulous patients with a history of periodontitis, with high survival implant rates. Smoking is a risk factor for implant failure. Bruxism may increase the incidence of mechanical complications with implant-supported fixed complete dentures, and the overall biologic complication incidence is comparatively high.

Systemic Diseases and Biological Dental Implant Complications: A Narrative Review

The relationship between periodontitis and such systemic disorders as diabetes, cardiovascular disease and obesity has been extensively investigated. There is less scientific evidence available, however, regarding the influence of systemic diseases on the risk of late failure of dental implant rehabilitation due to peri-implantitis. The aim of the present study was to review the literature on the role of several common systemic disorders (diabetes, obesity, cardiovascular disease, hypertension and osteoporosis) in the onset of peri-implantitis. A database search initially yielded 2787 studies of potential interest published up to 1 March 2022 (993 in PubMed; 908 in Web of Science; and 886 in Scopus). After removing 1190 duplicate articles and checking the titles, abstracts and full texts for relevance, 70 articles were selected for the present analysis. Only cohort, case-control studies and clinical case series were considered. Most of the literature concludes for no association between diabetes, cardiovascular disease, hypertension or osteoporosis and the risk of peri-implantitis. On the other hand, almost all the studies that investigated obesity as a risk factor for implant rehabilitation found a positive association between the two. Further longitudinal studies are needed to better understand the effects of systemic diseases on rehabilitation with dental implants.

Immediate flapless full-arch rehabilitation of edentulous jaws on 4 or 6 implants according to the prosthetic-driven planning and guided implant surgery: A retrospective study on clinical and radiographic outcomes up to 10 years of follow-up

OBJECTIVES

to retrospectively evaluate clinical and radiographic outcomes of immediate, flapless full-arch prostheses, supported by 4/6 implants according to prosthetic-driven planning and guided surgery.

MATERIALS AND METHODS

The study involved 28 edentulous patients (20 female/8 males; average age 67.75 ± 8.627 years), 32 prostheses (17 all-on-4/15 all-on-6) and 164 implants. The Implants survival, prostheses success/survival, peri-implant marginal bone loss, incidence of biological and prosthetic complications were evaluated. Multiple linear regression analysis was performed to analyze the influence of implant and patient characteristics on marginal bone loss.

RESULTS

Cumulative implant survival rate was 89.7% for all-on-four (seven failures) and 99.0% for all-on-six (one failure) after a mean follow-up of 6.46 ± 2.236 years (range 1-10 years). Cumulative prosthesis success rate was 51.5% (58.8% for all-on-four/ 43.8% for all-on-six). Prosthesis survival rate was 88.2% for all-on-four. No failure was registered in all-on-six. Mean value of marginal bone loss was 1.38 ± 0.1.28 mm at 5-year and 2.09 ± 0.56 mm at 10-year follow-up. No difference was found in the mean value of marginal bone resorption between all-on-four (1.56 ± 1.61 mm) and all-on-six (1.20 ± 0.85 mm) (p = 0.104) and between tilted (1.22 ± 1.29 mm) and axial implants (1.44 ± 1.27 mm) (p = 0.385) after 5-year follow-up. The incidence of biological complications was 1.0% in all-on-six (one mucositis) and 10.3% in all-on-four (two peri-implantitis). Prosthetic complications affected teeth of final rehabilitations with 3 detachments, 10 chippings or fractures, and 3 severe occlusal wears.

CONCLUSIONS

Based on the results and within the limitations of the present study, the implant-supported hybrid prosthesis according to prosthetic-driven planning and guided surgery showed to be an efficient, safe, and effective approach to rehabilitate edentulous jaws.

Immediate Functional Loading with Full-Arch Fixed Implant-Retained Rehabilitation in Periodontal Patients: Clinical Study

(1) Background. The immediate functional loading of implants is a clinical procedure used for treating periodontal edentulous patients. This clinical study aimed to evaluate the clinical outcomes of the immediate functional loading of implants with fully fixed rehabilitations in compromised periodontal patients. (2) Methods. Three hundred and five implants IPX screw implants were placed in 27 periodontal patients using an immediate functional loading protocol with fixed rehabilitations. All patients had a previous history of periodontitis, four patients (14.8%) were smokers and seven patients (25.9%) suffered from chronic medical conditions. (3) Results. Implant and prosthetic clinical findings were evaluated during a mean period of 41.3 ± 19.6 months. No implants were lost during the clinical follow-up. The cumulative survival rate for all implants was 100%. Regarding the prostheses designed, a total of 54 fixed prostheses were placed in the 27 patients immediately after the surgery. Forty-four hybrid fixed prostheses (81.5%) and 10 fixed rehabilitations (18.5%) were placed in the patients. The mean marginal bone loss was 1.51 ± 1.16 mm, ranging from 0 to 3.5 mm during the follow-up evaluation. Thirty-one implants (10.2%) in 10 patients (37%) were associated with peri-implantitis. Five patients (18.5%) showed some kind of technical complications (loss/fracture of the prosthetic screw, acrylic resin fracture, ceramic chipping). (4) Conclusions. The clinical outcomes of this study demonstrate that fixed rehabilitation by immediate functional loading of implants is considered a predictable procedure.

Digitally prefabricated versus conventionally fabricated implant-supported full-arch provisional prosthesis: a retrospective cohort study

Background

To evaluate and compare the clinical outcomes of digitally prefabricated and conventionally fabricated implant-supported full-arch provisional prostheses.

Methods

In this retrospective study, a total of 39 patients (22 males and 17 females) who underwent implant-supported full-arch rehabilitation using the All-on-4 concept with an immediate loading protocol were included: 20 patients treated with digitally prefabricated provisional prostheses were assigned into Group A, and 19 patients treated with conventionally fabricated provisional prostheses were assigned into Group B. Implant/provisional prosthesis survival rates and complications were reviewed. Marginal bone loss (MBL) was investigated by CBCT. Surgical time, restorative time, and total operative time were analyzed. Postoperative pain and swelling were evaluated with the visual analog scale (VAS). The oral health impact profile (OHIP) questionnaire was administered before and after surgery.

Results

The implant/provisional prosthesis survival rate was 100%, and complications appeared with low frequency in both groups, while the mean MBL was 0.30 ± 0.29 mm in Group A and 0.31 ± 0.41 mm in Group B after 3~ 6 months (P > 0.05). The average restorative time in Group A (116.16 ± 16.61 min) was significantly shorter than that in Group B (242.11 ± 30.14 min) (P < 0.05). Patients in Group A showed lower pain/swelling VAS scores after surgery than Group B (P < 0.05). Low OHIP scores with high satisfaction with the overall effects were shown in both groups.

Conclusion

Prefabricated prostheses reduced the prosthetic time and postoperative discomfort in patients whose immediate rehabilitation was based on the All-on-4 concept. This prefabrication technology may be a predictable alternative to improve the short-term clinical outcome of implant-supported full-arch provisional rehabilitation.

Efficacy of rehabilitation of stage IV periodontitis patients with full-arch fixed prostheses: Tooth-supported versus Implant-supported-A systematic review

OBJECTIVES

To evaluate the efficacy of implant-supported in comparison to tooth-supported full-arch prostheses in patients with stage IV periodontitis.

MATERIALS AND METHODS

Systematic electronic search (CENTRAL/MEDLINE/SCOPUS) up to March 2020 was conducted to identify randomized controlled trials and cohort-like studies comparing/evaluating fixed full-arch rehabilitation on teeth or implants in patients with stage IV periodontitis. The primary outcome measure was loss of teeth/implants and restorations. Data extraction was performed to create evidence tables, and meta-analyses were carried out as appropriate.

RESULTS

A total of 26 studies (31 publications) were identified but none addressed the scientific question in a controlled and randomized design. The risk of bias throughout the included studies was judged to be high, and meta-analyses demonstrated a high degree of heterogeneity. Mean-weighted observation periods in studies on tooth-supported restorations were significantly longer than in studies on implant-supported restorations. The predicted loss of teeth and tooth-supported full-arch restorations over 10 years was 1% and 5%, respectively. The 15-year estimates were 10% and 13%. Corresponding predictions for implants and implant-supported restorations for 10 years amounted to 4% and 6%, respectively. Technical complications were the most commonly reported and affected 8% of tooth-supported restorations (during 7.2 years) and 42% of implant-supported structures (during 2.6 years). Peri-implantitis- or peri-implantitis-like symptoms were observed at an estimated 9% of implants (after 3.1 years).

CONCLUSIONS

Based on observational studies on full-arch rehabilitation of stage IV periodontitis patients, 10-year estimates of tooth loss were lower than the corresponding estimates for implants. Estimated loss of tooth- and implant-supported restorations at 10 years was similar. Technical complications were more prevalent at implant-supported when compared to tooth-supported restorations.

Survival rates of axial and tilted implants in the rehabilitation of edentulous jaws using the All-on-four™ concept: A systematic review

Aim:

The aim of this review was to evaluate the survival rate of axial and tilted implants in rehabilitation of edentulous jaws using all on four concept.

Setting and Design:

Systematic Review.

Materials and Methods:

A literature review was performed in MEDLINE, PubMed Central (PMC), Google scholar, Embase, Cochrane Central Register of Controlled Trials. Hand searches were conducted of the bibliographic of related journals and systematic reviews. A total of 380 articles were obtained from the intial screening process. Of these articles, 25 articles fulfilled the inclusion criteria. The authors performed evaluation of articles independently as well as data extraction and quality assessment.

Statistical Analysis Used:

Qualitative analysis.

Results:

The major prosthetic complication was the fracture of the acrylic prosthesis. The mean cumulative survival rate of implants (72-132 months) were 94% to 98%. The prosthesis survival rate (12 months) was between 99% to 100%. The averaged bone loss was 1.3 ±0.4 mm (12-60 months). No Significant difference was found between survival rates of axial and tilted implants nor between maxilla and mandible.

Conclusion:

All on four concept can be employed successfully in the edentulous patients with resorbed ridges while improving their quality of life and reducing morbidity. However,randomized clinical trials with large sampling size and long term follow up should be incorporated.

Coating Polyelectrolyte Multilayers Loaded with Quercetin on Titanium Surfaces by Layer-By-Layer Assembly Technique to Improve Surface Osteogenesis Under Osteoporotic Condition

Titanium (Ti) and its alloy implants are widely used in the field of orthopedics, and osteoporosis is an important reason for implantation failure. This study aimed to establish a quercetin (QTN) controlled release system on the surface of titanium implants and to study its effects on osteogenesis and osseointegration on the surface of implants. Polyethylenimine (PEI) was first immobilized on a titanium substrate as the base layer, and then, hyaluronic acid/chitosan-quercetin (HA/CS-QTN) multilayer films were assembled on the PEI layer by a self-assembly technique. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and contact angle measurements were used to characterize and analyze the samples. The release characteristics of QTN were studied by release assays. The osteogenic ability of the samples was evaluated by experiments on an osteoporosis rat model and MC3T3-E1 cells. The FTIR, SEM, and contact angle measurements all showed that the PEI substrate layer and HA/CS-QTN multilayer film were successfully immobilized on the titanium matrix. The drug release test showed the successful establishment of a QTN controlled release system. The in vitro results showed that osteoblasts exhibited higher adhesion, proliferation and differentiation ability on the coated titanium matrix than on the pure titanium surface. In addition, the in vivo results showed that the HA/CS-QTN coating significantly increased the new bone mass around the implant. By depositing a PEI matrix layer and HA/CS-QTN multilayer films on titanium implants, a controlled release system of QTN was established, which improved implant surface osseointegration under osteoporotic conditions. This study proposes a new implant therapy strategy for patients with osteoporosis.

Six-year clinical outcomes of implant-supported acrylic vs. ceramic superstructures according to the All-on-4 treatment concept for the rehabilitation of the edentulous maxilla

The aim of the current study was to document the long-term clinical results of the use of two prosthetic techniques for the rehabilitation of completely edentulous maxillae according to the “All-on-Four” concept: Fixed, screw-retained prosthesis mounted on a chrome-molybdenum framework with (1) metal-ceramic veneers and (2) Acrylic prosthesis with acrylic resin prosthetic teeth. A total of 34 patients were assigned to subgroups according to their own preference of the superstructure type (ceramics [n: 17] or acrylic resin [n: 17]). Prosthetic complications, marginal bone loss, plaque accumulation, bleeding on probing, bite force and oral-health-related quality of life were assessed over a period of 6 years. Marginal bone loss around implants of the ceramic group remained well within the limits for ‘success’, as defined by the 2007 Pisa consensus over the time (1.43 ± 0.35 mm). However, marginal bone loss was significantly more pronounced around the implants in the acrylic group (2.15 ± 0.30) and the difference between two groups was statistically significant (p: 0.00). Bleeding on probing and plaque accumulation showed also positive correlation with marginal bone loss. Both acrylic and ceramic suprastructures appeared to be equivalent after 6 years; however, ceramic suprastructures revealed superior clinical results in terms of bone loss and plaque accumulation. Current study determines the long-term clinical outcomes of different prosthetic management alternatives in All-on-Four and aids to increase dental professionals’ ability to meet the patients’ expectations.

Patient-reported outcome measures and clinical assessment of implant-supported overdentures and fixed prostheses in mandibular edentulous patients: A systematic review and meta-analysis

STATEMENT OF PROBLEM

A consensus based on patients' perceptions as to whether to use overdentures or fixed prostheses to rehabilitate mandibular edentulous arches is limited.

PURPOSE

The purpose of this systematic review and meta-analysis was to compare the patient-reported outcome measures (PROMs) and clinical outcomes associated with implant-supported overdentures and fixed prostheses in edentulous mandibles.

MATERIAL AND METHODS

Nine electronic databases were searched for randomized clinical trials (RCTs) and nonrandomized clinical trials (N-RCTs). The risk of bias was assessed by the revised Cochrane risk of bias tool for RCTs (RoB 2) and N-RCT (ROBINS-I). Data sets for oral health-related quality of life (OHRQoL), satisfaction, survival rate, implant probing depth, and marginal bone loss were plotted, and the appropriate analyses were applied by using the Rev Man 5.3 software program. Certainty of evidence was also evaluated by means of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

Ten eligible trials were included and evaluated quantitatively. For 3 domains of OHRQoL, fixed prostheses showed significantly higher quality of life when compared with overdentures regarding functional limitation (P<.001), physical disability (P=.001), and physical pain (P=.003). Fixed prostheses also improved satisfaction, when compared with overdentures for comfort (P=.02), ease of chewing (P<.001), retention (P<.001), and stability (P<.001). The same pattern was observed for overall OHRQoL (P=.01) and satisfaction (P=.01) in which fixed prostheses improved patient satisfaction. Only ease of cleaning presented greater satisfaction for the overdenture group. Clinical parameters did not differ statistically (P>.05) between both types of prosthesis.

CONCLUSIONS

Fixed rehabilitations for mandibular edentulous patients seem to be a well-accepted treatment from the patients' oral health perspective. However, mandibular overdentures are no less efficient than fixed prostheses in terms of clinical outcomes.

Implant and prosthesis survival rates of full-arch immediate prostheses supported by implants with and without bicortical anchorage: Up to 2 years of follow-up retrospective study

OBJECTIVES

To compare implant and prosthesis survival rates between full-arch immediate prostheses supported by 4 hydrophilic implants with bicortical anchorage and by 5 or 6 hydrophilic implants placed without bicortical anchorage.

MATERIAL AND METHODS

The sample was retrospectively selected and comprised completely edentulous patients treated with full-arch immediate prostheses supported by Morse Taper hydrophilic implants. The selected patients were divided into four groups, according to the region of implant placement and type of anchorage. Differences in implant and prosthesis survival rates between groups, as well as the influence of bicortical anchorage on implant primary stability, were verified using Fisher's exact tests (significant at p < .05).

RESULTS

The sample comprised 392 implants, 72 were placed in the maxilla with bicortical anchorage, and 85 were placed without. In the mandible, 140 implants were placed with and 95 were placed without bicortical anchorage. The follow-up period was up to 24 months. A 98.8% implant survival rate was observed for the group of implants placed without bicortical anchorage in the maxilla, and of 100% for the other groups. The overall implant survival rate was 99.7% (391 of 392 implants). Prosthesis survival rate was 100% for all groups. No differences were observed between groups with respect to implant and prosthesis survival rates. Significantly higher primary stability was observed for implants placed with bicortical anchorage in both jaws.

CONCLUSION

Predictable results and high survival rates were achieved within the period evaluated by the present retrospective study, with immediate full-arch prostheses when only four hydrophilic implants are placed bicortically.

All-on-4 Concept Update

Over the past 17 years, the All-on-4 treatment concept has been a reliable and predictable modality to rehabilitate edentulous jaws with immediate function as full-arch prostheses. This article highlights clinically relevant data compiled by numerous All-on-4 investigators including complications and their remedies, occlusion and cantilever trends, implant size utilization, and controversial topics. We provide insights for navigating the complexities of medically diverse populations, faced by our daily practice, with a focus on patient avoidance, risk factors for implant and prosthetic failures, in hopes to minimize complications so clinicians would choose this treatment with confidence.

Surface Modified Techniques and Emerging Functional Coating of Dental Implants

Dental implants are widely used in the field of oral restoration, but there are still problems leading to implant failures in clinical application, such as failed osseointegration, marginal bone resorption, and peri-implantitis, which restrict the success rate of dental implants and patient satisfaction. Poor osseointegration and bacterial infection are the most essential reasons resulting in implant failure. To improve the clinical outcomes of implants, many scholars devoted to modifying the surface of implants, especially to preparing different physical and chemical modifications to improve the osseointegration between alveolar bone and implant surface. Besides, the bioactive-coatings to promote the adhesion and colonization of ossteointegration-related proteins and cells also aim to improve the osseointegration. Meanwhile, improving the anti-bacterial performance of the implant surface can obstruct the adhesion and activity of bacteria, avoiding the occurrence of inflammation related to implants. Therefore, this review comprehensively investigates and summarizes the modifying or coating methods of implant surfaces, and analyzes the ossteointegration ability and anti-bacterial characteristics of emerging functional coatings in published references.

Five-year survival rates for implants placed using digitally-designed static surgical guides: a systematic review

Digitally-designed static surgical guides provide an acceptable level of accuracy and predictability for the placement of dental implants. However, to our knowledge, few published studies have compared the long-term survival of implants placed in this way with those placed using other methods. A systematic search of electronic databases using a population, intervention, comparison, and outcome (PICO) framework was conducted of Medline and EMBASE, as well as grey literature and hand searches, to obtain all relevant work pertaining to the survival of dental implants placed by guided surgery. The studies were required to have at least 10 patients with a follow up of at least five years. A total of 621 titles were screened. Four studies met the inclusion criteria for quantitative analysis, and they all reported the exclusive use of Nobel Biocare implants and the NobelGuide system (Nobel Biocare Services). Cumulative survival rates ranged from 94.5% to 100% over five years. The survival rates of implants placed using digitally-designed static surgical guides are comparable to the estimated overall survival rate (95.6% over five years), despite the complex nature of the treatments done with guided surgery. Clinicians who do these operations should, however, have the experience and ability to revert to conventional freehand techniques if complications arise.

Prevalence and risk factors of peri-implant mucositis and peri-implantitis after at least 7 years of loading

Purpose

This study examined the prevalence and risk factors of peri-implant disease after at least 7 years of dental implant loading.

Methods

A total of 111 patients with 218 dental implants were treated. The follow-up period for all implants was at least 7 years. The patients' dental records were collected and risk factors of peri-implant disease were investigated through logistic regression analysis.

Results

The overall implant survival rate was 95.87%, because 9 of the 218 implants failed. The prevalence of peri-implant mucositis and peri-implantitis was 39.7% and 16.7%, respectively. As risk factors, smoking and prosthetic splinting showed significant associations with peri-implantitis (P<0.05).

Conclusions

Within the limits of this study, no significant correlations were found between any risk factors and peri-implant mucositis, but a significantly elevated risk of peri-implantitis was observed in patients who smoked or had splinted prostheses in 2 or more implants.

Are There Alternatives to Invasive Site Development for Dental Implants? Part II

Despite improvements in bone preservation following tooth extraction, edentulous sites are often deficient in bone volume for conventional dental implant therapy. Missing bone volume is often recaptured by surgery and grafting. This article discusses noninvasive alternatives to bone grafting. Part I of this topic discussed the use of short and narrow diameter implants. Part II discusses three additional alternatives: the use of tilted implants, the use of four or fewer tilted and axially-loaded implants to support a full-arch fixed-dental-prosthesis (FAFDP), and the use of zygomatic implants to restore the severely-atrophic edentulous maxillae lacking adequate bone for conventional treatment.

Clinical performance of intentionally tilted implants versus axially positioned implants: A systematic review

OBJECTIVES

The aim of this review was to determine the clinical performance of dental implants that are intentionally tilted when compared with implants that are placed following the long axis of the residual alveolar ridge.

MATERIALS AND METHODS

A systematic review of the scientific literature using a predefined research question (PICO) and search strategy was undertaken. This search included five electronic databases. Two independent reviewers examined electronic databases and performed a manual review following search strategy to accomplish the item generation and reduction. Included articles were evaluated to determine the level of evidence. Data were extracted only from level I and level II studies, based on the Oxford Centre for Evidence-based Medicine-Levels of Evidence (March 2009). If included studies were homogeneous in nature, data were to be accumulated. However, if included studies were heterogeneous in nature, only descriptive data would be reviewed and analyzed.

RESULTS

A total of 811 articles were identified through the PICO question and search strategy. Detailed review of the abstracts and articles resulted in further item reduction, and 46 articles were included for full-text review. A total of 42 articles were then selected for inclusion in the systematic review. The identified articles included two level I and 20 level II studies. In addition, 15 level IV, one gray literature, and four previous systematic reviews with meta-analyses were also used in the study. The extracted data from the included studies demonstrated heterogeneity that prevented quantitative assessment, and only one level II study directly compared tilted and axially placed implants. Assessment of the descriptive data demonstrated no differences in implant survival, marginal bone loss, prosthesis survival, or patient-reported outcome measures (PROMs) whether implants are placed axially or with intentional inclination of the coronal aspect of the implant toward the distal aspect of edentulous jaws.

CONCLUSIONS

Based upon the systematic review of the literature, an analysis of the descriptive data suggested no differences in clinical performance between implants that are placed in an axial position relative to the residual alveolar ridge when compared with implants that are intentionally tilted toward the distal aspect of edentulous jaws.

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.

Implant-supported overdentures with different clinical configurations: Mechanical resistance using a numerical approach

STATEMENT OF PROBLEM

Implant-supported overdentures (IODs) are a treatment option for patients with complete edentulism. However, this treatment increases the possibilities of peri-implant complications, characterized by inflammation or partial loss of surrounding hard and soft tissues.

PURPOSE

The purpose of this finite element analysis study was to evaluate the mechanical performance of different bar-IOD designs under different clinical configurations by comparing the stress and strain distribution on the bone during secondary stabilization.

MATERIAL AND METHODS

A finite element model of the mandible representing a patient with complete edentulism was developed. Different designs of bar-IODs were modeled and compared. The parameters studied were the material properties (cobalt-chromium, zirconium dioxide, titanium grade 5, and titanium grade 4), diameter and bar-IOD cross-sectional shape, tilt of the posterior implants (30 degrees), presence of a distal extension cantilever in the bar-IODs (12 mm), and number of implants (4 or 6). Two different mastication loading conditions were analyzed. One- and 2-way ANOVAs and the Tukey honestly significant differences post hoc test (α=.05) were used to determine the significant von Mises stress and strain values in the bone.

RESULTS

The 4 materials tested in the bar-IOD did not have a significant mechanical effect on the bone (P<.05). A smaller diameter and structure of the bar-IOD led to significantly higher bone stress (P<.001). A distal extension cantilever led to an increased stress concentration (model M1 versus model M3: P<.001), which reached 50% in the event of tilting of the posterior implants (model M2 versus model M4: P<.001). Tilting of the posterior implants alone, without extension, had a nonsignificant effect (model M3 versus model M4: P=.999). Model M5 supported with 6 implants reduces the stress transferred to the bone compared with model M3 supported with 4 implants (P<.05).

CONCLUSIONS

Distal extensions in bar-IODs, the tilt of the posterior implants, and the low amount of material in the cross-sectional area in the bar-IOD were the most influential parameters on the mechanical resistance of dental implants in the mandibular bone.

Satisfaction analysis of patients with single implant treatments based on a questionnaire survey

Background: The factors influencing satisfaction of the patients with implant treatments are still unclear. This study aims to evaluate the patients' satisfaction and to identify influencing factors, which will improve the medical quality of oral implantology. Materials and methods: Patients who lost single teeth and received implant treatments were enrolled in Nanjing Stomatological Hospital between February 2016 and March 2018. A questionnaire survey was performed to assess patient satisfaction and data were collected at four time points. Information included gender, age, educational level, application of bone augmentation, type of prosthetic restoration, period of teeth loss, dentist qualification, and tooth position. Meanwhile, the satisfaction of the patients was evaluated by visual analog scale. Results: A total of 373 patients completed the questionnaires. The mean of overall satisfaction score was 69.05±7.10. Lower overall satisfaction score was found in patients who received bone augmentation (P<0.001) and those with a longer period of teeth loss (P<0.05). In the bone augmentation group, the elements of pain and complication were significantly associated with a decrease in the median satisfaction score (P<0.001), and a similar result was obtained form the duration of operative time and healing response (P<0.001). On the other hand, the satisfaction scores for elements including the duration of operative time and healing response (P<0.05), aesthetics and psychology (P<0.05), and chewing function (P<0.05) decreased with an extended period of teeth loss. Meanwhile, over half of respondents were more concerned about the survival time (40.70%) and success rate (20.49%) of implants. Conclusion: Bone augmentation and the period of teeth loss are negative factors affecting patient satisfaction, and the success rate and survival time of implants are considerable aspects for patients. It is essential to raise general awareness of oral hygiene and optimize the dental implant therapeutic process.

The all-on-four treatment concept: Systematic review

Objectives

To systematically review the literature on the “all-on-four” treatment concept regarding its indications, surgical procedures, prosthetic protocols and technical and biological complications after at least three years in function.

Study Design

The three major electronic databases were screened: MEDLINE (via PubMed), EMBASE, and the Cochrane Library of the Cochrane Collaboration (CENTRAL). In addition, electronic screening was made of the ‘grey literature’ using the System for Information on Grey Literature in Europe - Open Grey, covering the period from January 2005 up to and including April 2016.

Results

A total of 728 articles were obtained from the initial screening process. Of these articles, 24 fulfilled the inclusion criteria. Methodological quality assessment showed sample size calculation to be reported by only one study, and follow-up did not include a large number of participants - a fact that may introduce bias and lead to misleading interpretations of the study results.

Conclusions

The all-on-four treatment concept offers a predictable way to treat the atrophic jaw in patients that do not prefer regenerative procedures, which increase morbidity and the treatment fees. The results obtained indicate a survival rate for more than 24 months of 99.8%. However, current evidence is limited due the scarcity of information referred to methodological quality, a lack of adequate follow-up, and sample attrition. Biological complications (e.g., peri-implantitis) are reported in few patients after a mean follow-up of two years. Adequate definition of the success / survival criteria is thus necessary, due the high prevalence of peri-implant diseases.

Key words:All-on-four, all-on-4, tilted implants, dental prostheses, immediate loading.