Turned versus anodised dental implants: a meta-analysis

Multiscale Hierarchical Micro- and Nano-Surface Induced by High-Repetition-Rate Femtosecond Laser Promote Peri-Implant Osseointegration

Micro- and nanomorphological modification and roughening of titanium implant surfaces can enhance osseointegration; however, the optimal morphology remains unclear. Laser processing of implant surfaces has demonstrated significant potential due to its precision, controllability, and environmental friendliness. Femtosecond lasers, through precise optimization of processing parameters, can modify the surface of any solid material to generate micro- and nanomorphologies of varying scales and roughness. Inspired by the multiscale micro- and nanostructures of natural bone tissue, this study employed a high-repetition-rate femtosecond laser to fabricate three distinct micro- and nanomorphologies on titanium implant surfaces, characterized by low (LTi), medium (MTi), and high (HTi) roughness, exhibiting multiscale coexistence. Comprehensive characterization of the modified surfaces included analysis of morphology, roughness, wettability, and elemental composition. Furthermore, in vitro and in vivo experiments were conducted to evaluate osteogenic differentiation and osseointegration capabilities. Results revealed that the HTi surface, exhibiting high roughness, presents a multiscale hierarchical micro- and nanostructure composed of micrometer-sized spheres, submicrometer-sized corrugations, and nanometer-sized particles. In vitro studies demonstrated that the HTi surface promoted earlier adhesion, spreading, and enhanced osteogenic differentiation of osteoblasts, while in vivo studies indicated improved bone formation and osseointegration. In conclusion, multiscale hierarchical micro- and nanosurfaces with high roughness generated by high-repetition-rate femtosecond laser processing hold considerable promise for titanium implant applications.

The Influence of Osteoporosis and Diabetes on Dental Implant Stability: A Pilot Study

Background and Objectives: Dental implants are a reliable solution for tooth loss; however, systemic conditions like osteoporosis and diabetes, which affect bone quality, healing, and stability, underline the importance of understanding their impact on enhanced outcomes. This study evaluated the comparative effects of osteoporosis and diabetes on dental implant stability over 12 months, utilizing objective implant mobility and stability measures. Materials and Methods: This prospective cohort study involved 50 patients, divided into 21 with type 2 diabetes and 29 with osteoporosis, with implant stability assessed at 6 and 12 months using Osstell ISQ and Periotest M devices and statistical analysis identifying differences between groups and time intervals at a significance level of p < 0.05. Results: At 6 months, the osteoporosis group showed higher initial stability (mean ISQ: 67.04 ± 5.42) compared to the diabetes group (mean ISQ: 62.10 ± 5.46; p = 0.0215)), and by 12 months, both groups showed significant improvements in ISQ scores (osteoporosis: 68.93 ± 4.83; diabetes: 65.79 ± 3.87), with Periotest values indicating more significant reductions in implant mobility, particularly in diabetic patients (osteoporosis: -3.34 ± 1.59; diabetes: -2.81 ± 1.44; p = 0.0001). Conclusions: Osteoporosis and diabetes significantly impact implant stability through distinct osseointegration pathways, emphasizing the need for personalized treatment plans to improve patient outcomes.

Clinical Outcomes of Maxillary Sinus Floor Perforation by Dental Implants and Sinus Membrane Perforation during Sinus Augmentation: A Systematic Review and Meta-Analysis

The aim of the present systematic review was to investigate the clinical outcomes after the perforation of the maxillary sinus by dental implants, or after maxillary sinus membrane perforation during sinus lift procedure. Twenty-nine publications were included. Failure rates of implants in cases where perforation of sinus floor had happened (11 studies) was generally low, and only one case of transient sinusitis was reported. The estimated failure rate of these implants was 2.1% (SE 1.0%, p = 0.035). There were 1817 implants (73 failures) placed in augmented sinuses in which the sinus membrane was perforated and 5043 implants (274 failures) placed in sinuses with no perforated membrane, from 18 studies. The odds of implant failure difference between the groups were not significant (OR 1.347, p = 0.197). log OR of implant failure between perforated and non-perforated membrane groups did not significantly change with the follow-up time (-0.004/month; p = 0.500). In conclusion, implant failure rate is generally low either for implants penetrating in the floor of the maxillary sinus or implants placed in augmented sinuses in which the sinus membrane was perforated. The prevalence of postoperative infection/sinusitis is low, and it may depend either on the dimensions of the perforation or on the anatomical predisposition.

Clinical outcomes of zirconia implants: a systematic review and meta-analysis

PURPOSE

To assess the clinical outcomes of zirconia dental implants based on an updated systematic literature review.

METHODS

An electronic search was performed in three databases, last updated in June 2023, supplemented by hand searching. The eligibility criteria were clinical studies reporting patients rehabilitated with zirconia implants. The cumulative survival rate (CSR) of implants was calculated. A meta-analysis for marginal bone loss (MBL) under different follow-up times and a meta-regression assessing the relationship between mean MBL and follow-up were done.

RESULTS

Twenty-five studies were included (4017 implants, 2083 patients). Seven studies had follow-up longer than 60 months. 172 implants failed, after a mean of 12.0 ± 16.1 months (min-max 0.3-86.0), of which 47 early failures, and 26 due to implant fracture, the majority in narrow-diameter implants. The 10-year CSR was 95.1%. Implants with coronal part prepared by drills presented statistically significant lower survival than non-prepared implants (p < 0.001). Two-piece implants presented lower survival than one-piece implants (p = 0.017). Implants discontinued from the market presented lower survival than the commercially available ones (p < 0.001). The difference in survival was not significant between implants in maxilla and mandible (p = 0.637). The mean MBL fluctuated between 0.632 and 2.060 mm over long periods of observation (up until 132 months). There was an estimated MBL increase of 0.005 mm per additional month of follow-up.

CONCLUSION

Zirconia implants present high 10-year CSR and short-term low MBL. The review was registered in PROSPERO (CRD42022342055).

CLINICAL RELEVANCE

The clinical outcomes observed for zirconia dental implants are very promising, although these have not yet been extensively studied as titanium alloy implants.

Difference in marginal bone loss around implants between short implant-supported partial fixed prostheses with and without cantilever: a retrospective clinical study

PURPOSE

To investigate the influence of cantilever prosthetic arm on the marginal bone loss (MBL) over time around dental implants supporting short fixed partial dentures (FPDs), in a record-based retrospective study.

METHODS

All cases of 3-unit implant-supported FPDs, supported by 2-3 implants, from the database of cases treated at one specialist clinic were considered for inclusion. Only implants with a minimum of 36 months of radiological follow-up were considered. Univariate linear regression models were used to compare MBL over time between 12 clinical covariates, after which a linear mixed-effects model was built.

RESULTS

One-hundred-thirty-nine patients (64 men, 75 women) with 164 3-unit implant-supported FPDs (333 implants supporting non-cantilevered FPDs, 94 supporting cantilevered FPDs) were included in the study. The patients were followed up clinically and radiographically for a mean of 154.1 ± 78.0 (min-max, 37.3-364.6) and 132.9 ± 77.3 months (min-max, 36.8-329.9), respectively. The total number of marginal bone level double measurements (mesial and distal sides of each implant) was 2909. FPDs with cantilever presented an estimated greater MBL over time compared to FPDs without cantilever. Bruxism, sex (women), implant (modified) surface, and (poor) bone quality were also associated with higher MBL over time.

CONCLUSIONS

The use of a cantilever extension is suggested to negatively affect the bone marginal level over time around implants supporting 3-unit FPDs. Due to the small difference of the estimated MBL over long periods of follow-up between the groups, it is a matter of debate if the observed negative effect may be of clinical significance.

Laser-Induced µ-Rooms for Osteocytes on Implant Surface: An In Vivo Study

Laser processing of dental implant surfaces is becoming a more widespread replacement for classical techniques due to its undeniable advantages, including control of oxide formation and structure and surface relief at the microscale. Thus, using a laser, we created several biomimetic topographies of various shapes on the surface of titanium screw-shaped implants to research their success and survival rates. A distinctive feature of the topographies is the presence of "µ-rooms", which are special spaces created by the depressions and elevations and are analogous to the µ-sized room in which the osteocyte will potentially live. We conducted the comparable in vivo study using dental implants with continuous (G-topography with µ-canals), discrete (S-topography with μ-cavities), and irregular (I-topography) laser-induced topographies. A histological analysis performed with the statistical method (with p-value less than 0.05) was conducted, which showed that G-topography had the highest BIC parameter and contained the highest number of mature osteocytes, indicating the best secondary stability and osseointegration.

Dental Implants: Enhancing Biological Response Through Surface Modifications

Surface characteristics are an important factor for long-term clinical success of dental implants. Alterations of implant surface characteristics accelerate or improve osseointegration by interacting with the physiology of bone healing. Dental implant surfaces have been traditionally modified at the microlevel. Recently, researchers have actively investigated nano-modifications in dental implants. This review explores implant surface modifications that enhance biological response at the interface between a bone and the implant.

In vitro antimicrobial effect of titanium anodization on complex multispecies subgingival biofilm

Anodization is a routine industrial galvanic method that produces a titanium oxide layer on the surface of titanium. Considering the possibility that this technique could influence microbial adsorption and colonization, this in vitro study was conducted to evaluate the impact of a process of anodization applied to a titanium surface on the microbial profile of multispecies subgingival biofilm. Titanium discs produced by using two different processes-conventional and Anodization-were divided into two groups: conventional titanium discs with machined surface (cpTi) Control Group and titanium discs with anodic oxidation treatment (anTi) Test Group. Subgingival biofilm composed of 33 species was formed on the titanium discs that were positioned vertically in 96-well plates, for 7 days. The proportions and the counts of microbial species were determined using a DNA-DNA hybridization technique, and data were evaluated using Mann-Whitney test (p < 0.05). Mean total bacterial counts were lower in Test Group in comparison with Control Group (p < 0.05). Nine bacterial species differed significantly, and were found in higher levels in Control Group in comparison with Test Group, including T. forsythia, E. nodatum, and F. periodonticum. In conclusion, titanium discs with anodization could alter the microbial profile of the biofilm formed around them. Further clinical studies should be conducted to confirm the clinical impact of these findings.

Diabetes Mellitus and Dental Implants: A Systematic Review and Meta-Analysis

The present review aimed to evaluate the impact of diabetes mellitus on dental implant failure rates and marginal bone loss (MBL). An electronic search was undertaken in three databases, plus a manual search of journals. Meta-analyses were performed as well as meta-regressions in order to verify how the odds ratio (OR) and MBL were associated with follow-up time. The review included 89 publications. Altogether, there were 5510 and 62,780 implants placed in diabetic and non-diabetic patients, respectively. Pairwise meta-analysis showed that implants in diabetic patients had a higher failure risk in comparison to non-diabetic patients (OR 1.777, p < 0.001). Implant failures were more likely to occur in type 1 diabetes patients than in type 2 (OR 4.477, p = 0.032). The difference in implant failure between the groups was statistically significant in the maxilla but not in the mandible. The MBL mean difference (MD) between the groups was 0.776 mm (p = 0.027), with an estimated increase of 0.032 mm in the MBL MD between groups for every additional month of follow-up (p < 0.001). There was an estimated decrease of 0.007 in OR for every additional month of follow-up (p = 0.048). In conclusion, implants in diabetic patients showed a 77.7% higher risk of failure than in non-diabetic patients.

Retrospective study comparing the clinical outcomes of bar-clip and ball attachment implant-supported overdentures

The aim of this study was to compare the clinical outcomes of implant-supported overdentures (ODs) with either bar-clip or ball attachments. The implant, prosthesis failure, and technical complications were the outcomes analyzed in this retrospective clinical study conducted in a specialty clinic. Seventy-five patients with 242 implants supported by 76 ODs (36 maxillary, 40 mandibular) were included in the study and followed up for 88.8 ± 82.9 months (mean ± standard deviation). Bar-clip and ball attachments were used in 78.9% and 21.1% of the cases, respectively. Forty-three implant failures (17.8%) in 17 prostheses (17/76; 22.4%) were observed in this study. The average period of implant failure was 43.3 ± 41.0 months, and most of them were maxillary turned implants. The bar-clip system demonstrated more complications in the attachment parts compared to the ball attachment system. Poor retention of the prosthesis was similar between the two systems. Loss of implants resulted in the failure of 10 ODs in this study. ODs opposed by natural dentition or fixed prostheses presented with more complications. The Cox proportional hazards model did not show a significant effect on prosthesis failure for any of the factors. These findings indicated that patients with ODs need constant maintenance follow-ups to address the technical complications and perform prosthodontic maintenance regardless of the attachment system used.

Retrospective clinical evaluation of 2- to 6-unit implant-supported fixed partial dentures: Mean follow-up of 9 years

BACKGROUND

Implant-supported fixed partial dentures (ISFPDs) are one of the most common options to rehabilitate partially edentulous patients.

PURPOSE

To assess the clinical outcomes of ISFPDs.

METHODS

This retrospective study included all patients treated with ISFPDs with 2 to 6 prosthetic units at one specialist clinic. Implant/prosthesis failure and technical complications were the outcomes analyzed.

RESULTS

Six hundred and forty-two patients with 876 ISFPDs (2241 implants) were included, followed up for 108.0 ± 76.2 months. Eighty-eight prostheses and 112 implants (26 before, 86 after prosthesis installation) failed. The estimated CSR of ISFPDs at 30 years was 72.7%. Smokers presented lower implant survival than nonsmokers. Two hundred and ninety-nine ISFPDs (33.2%) presented technical complications. Bruxism was a factor to exert a higher risk of screw and implant fracture, and ceramic chipping. ISFPDs with cantilever presented higher risk of failure, and screw loosening/fracture. Prostheses supported by implants with internal abutment connection or with two pontics had higher risk of presenting ceramic chipping. Extension of the prosthesis did not seem to exert influence on prosthesis failure/complications.

CONCLUSIONS

ISFPDs presented good long-term prognosis. Implant failure was the main reason for ISFPD failure. The results suggest that bruxism and the presence of cantilever may contribute to the increased rate of mechanical complications and prosthesis failure.

Comparison between flapless and open-flap implant placement: a systematic review and meta-analysis

No consensus has been reached regarding the influence of the flapless and open-flap surgical techniques on the placement of dental implants. This systematic review compared the effects of flapless implant placement and implant placement with elevation of the mucoperiosteal flap in terms of marginal bone loss, implant survival rate and complications rates. This review followed PRISMA guidelines and was registered in PROSPERO with the registration number CRD42017071475. Two independent reviewers performed a comprehensive search of the PubMed/MEDLINE, Scopus, and Cochrane Library databases for studies published until December 2017. The search identified 559 references. After a detailed review, 24 studies were assessed for eligibility. A total of 1025 patients who had received a total of 1873 dental implants were included. There were no significant differences between the flapless and open-flap surgical techniques in terms of implant survival rates (P=0.34; risk ratio (RR): 1.36; confidence interval (CI): 0.72-2.56), marginal bone loss (P=0.23; MD: -0.20; CI: -0.52-0.13), or complication rates (P=0.67; RR: 1.10; CI: 0.70-1.73). The current meta-analysis showed that the implant survival rate, marginal bone levels, and complications of flapless surgery were similar to those of open-flap surgery over a mean follow-up period of 21.62 months.

Modifications of Dental Implant Surfaces at the Micro- and Nano-Level for Enhanced Osseointegration

This review paper describes several recent modification methods for biocompatible titanium dental implant surfaces. The micro-roughened surfaces reviewed in the literature are sandblasted, large-grit, acid-etched, and anodically oxidized. These globally-used surfaces have been clinically investigated, showing survival rates higher than 95%. In the past, dental clinicians believed that eukaryotic cells for osteogenesis did not recognize the changes of the nanostructures of dental implant surfaces. However, research findings have recently shown that osteogenic cells respond to chemical and morphological changes at a nanoscale on the surfaces, including titanium dioxide nanotube arrangements, functional peptide coatings, fluoride treatments, calcium–phosphorus applications, and ultraviolet photofunctionalization. Some of the nano-level modifications have not yet been clinically evaluated. However, these modified dental implant surfaces at the nanoscale have shown excellent in vitro and in vivo results, and thus promising potential future clinical use.

Al2O3 Particles on Titanium Dental Implant Systems following Sandblasting and Acid-Etching Process

Dental implants with moderately rough surfaces show enhanced osseointegration and faster bone healing compared with machined surfaces. The sandblasting and acid-etching (SA) process is one technique to create moderately rough dental implant surfaces. The purpose of this study was to analyse different commercially available implant systems with a SA-modified surface and to explore the widespread notion that they have similar surface properties regarding morphology and cleanliness. SA-modified surfaces of nine implant systems manufactured by Alpha-Bio Tec Ltd, Camlog Biotechnologies AG, Dentsply Sirona Dental GmbH, Neoss Ltd, Osstem Implant Co. Ltd, Institute Straumann AG, and Thommen Medical AG were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) and examined for surface cleanliness. Six implants from three different lots were selected per each implant system. Mean particle counts for each implant and the mean size of the particles were calculated from three different regions of interest and compared using ANOVA and Tukey's test. SEM analysis showed presence of particles on the majority of analyzed implant surfaces, and EDX evaluations determined that the particles were made of Al₂O₃ and thus remnants of the blasting process. SPI®ELEMENT INICELL® and Bone Level (BL) Roxolid® SLActive® implant surfaces showed the highest mean particle counts, 46.6 and 50.3 per area, respectively. The surface of BL Roxolid® SLActive® implant also showed the highest variations in the particle counts, even in samples from the same lot. The mean size of particles was 1120±1011 μm², measured for USIII CA Fixture implants, while the biggest particle was 5900 μm² found on a BL Roxolid® SLActive® implant. These results suggest that not all manufacturers are able to produce implant surfaces without particle contamination and highlight that the surface modification process with the SA technique should be appropriately designed and controlled to achieve a clean and consistent final medical device.

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.

Safety and efficacy of a novel anodized abutment on soft tissue healing in Yucatan mini-pigs

BACKGROUND

It is well established that electrochemical anodization of implant surfaces contributes to osseointegration and long-term implant survival. Few studies have investigated its effect on soft tissue healing.

PURPOSE

To evaluate the safety and efficacy of a novel abutment surface prepared by electrochemical oxidation compared to commercially available machined titanium abutments.

MATERIALS AND METHODS

Twelve 16-19 months-old, Yucatan mini-pigs received three dental implants in each mandibular jaw quadrant. Each side was randomized to receive either an anodized or a machined titanium abutment. Titanium healing caps were placed on both abutments. Animals were euthanized at 6 and 13 weeks. Radiographic and histological analyses were performed.

RESULTS

No significant differences were observed histologically between groups in regard to inflammation, epithelium length, mucosal height, bone-to-implant contact, or bone density for any time point. Radiographically, crestal bone level change from baseline to 6 weeks was significantly lower for anodized than machined abutments (P = 0.046); no significant differences were observed at 13 weeks (P = 0.12).

CONCLUSIONS

The novel anodized abutment showed a comparable effect on soft and hard tissue healing/remodeling and inflammation reaction to standard titanium abutments. Clinical studies should confirm these findings and explore the positive radiographic results observed at the early time point.

Should the restoration of adjacent implants be splinted or nonsplinted? A systematic review and meta-analysis

STATEMENT OF PROBLEM

The decision to splint or to restore independently generally occurs during the planning stage, when the advantages and disadvantages of each clinical situation are considered based on the proposed treatment. However, clinical evidence to help clinicians make this decision is lacking.

PURPOSE

The purpose of this systematic review and meta-analysis was to assess the marginal bone loss, implant survival rate, and prosthetic complications of splinted and nonsplinted implant restorations.

MATERIAL AND METHODS

This study was designed according to the Cochrane criteria for elaborating a systematic review and meta-analysis and adopted the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Also, this review was registered at the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42017080162). An electronic search in the PubMed/MEDLINE, Cochrane Library, and Scopus databases was conducted up to November 2017. A specific clinical question was structured according to the population, intervention, comparison, outcome (PICO) approach. The addressed focused question was "Should the restoration of adjacent implants be splinted or nonsplinted?" The meta-analysis was based on the Mantel-Haenszel and inverse variance methods to assess the marginal bone loss, implant survival, and prosthetic complications of splinted and nonsplinted implant restorations.

RESULTS

Nineteen studies were selected for qualitative and quantitative analyses. A total of 4215 implants were placed in 2185 patients (splinted, 2768; nonsplinted, 1447); the mean follow-up was 87.8 months (range=12-264 months). Quantitative analysis found no significant differences between splinted and nonsplinted restorations for marginal bone loss. The assessed studies reported that 75 implants failed (3.4%), of which 24 were splinted (99.1% of survival rate) and 51 were nonsplinted (96.5% of survival rate). Quantitative analysis of all studies showed statistically significant higher survival rates for splinted restorations than for nonsplinted restorations. Ceramic chipping, screw loosening, abutment screw breakage, and soft tissue inflammation were reported in the selected studies. The quantitative analysis found no statistically significant difference in the prosthetic complications of splinted and nonsplinted restorations.

CONCLUSIONS

Within the limitations of this systematic review and meta-analysis, it was concluded that there was no difference in the marginal bone loss and prosthetic complications of splinted and nonsplinted implant restorations; this is especially true for restorations in the posterior region. However, splinted restorations were associated with decreased implant failure.