Scanning electron microscopy and microbiological approaches for the evaluation of salivary microorganisms behaviour on anatase titanium surfaces: In vitro study

Surface-Mediated Modulation of Different Biological Responses on Anatase-Coated Titanium

Various surface modification strategies are being developed to endow dental titanium implant surfaces with micro- and nano-structures to improve their biocompatibility, and first of all their osseointegration. These modifications have the potential to address clinical concerns by stimulating different biological processes. This study aims to evaluate the biological responses of ananatase-modified blasted/etched titanium (SLA-anatase) surfaces compared to blasted/acid etched (SLA) and machined titanium surfaces. Using unipolar pulsed direct current (DC) sputtering, a nanocrystalline anatase layer was fabricated. In vitro experiments have shown that SLA-anatase discs can effectively promote osteoblast adhesion and proliferation, which are regarded as important features of a successful dental implant with bone contact. Furthermore, anatase surface modification has been shown to partially enhance osteoblast mineralization in vitro, while not significantly affecting bacterial colonization. Consequently, the recently created anatase coating holds significant potential as a promising candidate for future advancements in dental implant surface modification for improving the initial stages of osseointegration.

How MALDI-TOF Mass Spectrometry Technology Contributes to Microbial Infection Control in Healthcare Settings

Healthcare settings have been utilizing matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) since 2010. MALDI-TOF MS has various benefits over the conventional method of biochemical identification, including ease of use, speed, accuracy, and low cost. This approach can solve many of the obstacles to identifying bacteria, fungi and viruses. As technology advanced, more and more databases kept track of spectra, allowing species with similar morphological, genotypic, and biochemical traits to be identified. Using MALDI-TOF MS for identification has become more accurate and quicker due to advances in sample preparation and database enrichment. Rapid sample detection and colony identification using MALDI-TOF MS have produced promising results. A key application of MALDI-TOF MS is quickly identifying highly virulent and drug-resistant diseases. Here, we present a review of the scientific literature assessing the effectiveness of MALDI-TOF MS for locating clinically relevant pathogenic bacteria, fungi, and viruses. MALDI-TOF MS is a useful strategy for locating clinical pathogens, however, it also has some drawbacks. A small number of spectra in the database and inherent similarities among organisms can make it difficult to distinguish between different species, which can result in misidentifications. The majority of the time additional testing may correct these problems, which happen very seldom. In conclusion, infectious illness diagnosis and clinical care are being revolutionized by the use of MALDI-TOF MS in the clinical microbiology laboratory.

SEM-EDX Analysis of Metal Particles Deposition from Surgical Burs after Implant Guided Surgery Procedures

The preparation of the implant site in guided surgery procedure takes place without irrigation, which could lead to increased friction of the drills with the formation and release of debris or metal particles. The presence of metal particles in the peri-implant tissue could represent a trigger for macrophage activity, bone resorption processes, and consequent implant loss. According to the guided surgical protocol, the study aimed to evaluate the presence of metal particles deposited during implant site preparation. Twenty-five adult porcine ribs from the same adult individual were chosen due to their trabecular bone structure, similar to facial bones. The samples were all 8 cm (length) × 3 cm (depth) × 2 cm (width) and were further subdivided to obtain 50 elements of 4 cm × 3 cm × 2 cm. Plexiglass was used to create structures such as surgical guides so that their function could be mimicked, and the guided implant site preparation sequence could be performed with them. The drill kit used in this study is a guided surgery drill kit characterized by high wear resistance, high yield strength, and good corrosion resistance. This same kit was used 50 times in this way to prepare 50 different implant sites and evaluated at different edges and number of preparation (T0-neutral edge, T1-1 full preparation, T2-10, T3-20, T4-30, T5-40, and T6-50) by SEM-EDX to assess the presence of any metal deposition. The presence of metal residues in the implant site increased according to the cycles of use of the drills. We have observed that in the first three groups, there is no presence of metals. This is evident in groups T3 and T4. Finally, the presence of metal residues becomes significant in the study’s last two groups of samples. The study highlighted how the lack of irrigation in the work site leads the deposition of metal particles and in addition to a reduction in the efficiency of the drills, resulting in less precise cutting, altering the shape of the prepared site, and, lastly, reducing the primary stability of the implants.

Subinhibitory Antibiotic Concentrations Enhance Biofilm Formation of Clinical Enterococcus faecalis Isolates

Enterococcus faecalis is a microorganism that can be found in the oral cavity, especially in secondary endodontic infections, with a prevalence ranging from 24-70%. The increase in the ability to form biofilms in the presence of subinhibitory antibiotic concentrations is a phenomenon that is observed for a wide variety of bacterial pathogens and is associated with increased resistance. In this study, therefore, six E. faecalis isolates from an endodontic environment and two control strains were exposed to subinhibitory concentrations of Penicillin G, Amoxicillin, Doxycycline, Fosfomycin, Tetracycline and Vancomycin and examined for their biofilm formation abilities. The minimum inhibitory concentration (MIC) was determined for all E. faecalis isolates. A culture of the isolate was mixed with a serial dilution series of the respective antibiotic, incubated overnight and the biofilm formation was analyzed using a microtiter plate assay. All isolates were able to form biofilms in the absence of an antibiotic. A significant increase in biofilm formation of up to more than 50% was found in the isolates exposed to subinhibitory concentrations of various antibiotics. Most isolates showed a significant increase in Fosfomycin (7/8), Doxycycline (6/8) and Tetracycline (6/8). Three endodontic isolates showed a significant increase in five of the antibiotics examined at the same time. On exposure to Vancomycin, three endodontic isolates and the two control strains showed an increase. The increase in the ability to form biofilms extended over a concentration range from 1/2 to 1/64 of the MIC concentration. Antibiotics may reach certain niches in the oral cavity at subinhibitory concentrations only. This can increase the biofilm formation by enterococci, and in turn lead to decreased susceptibility of these taxa to antibiotics.

Repeated hyperstimulation affects the ultrastructure of mouse fallopian tube epithelium

Controlled ovarian hyperstimulation (COH) is routinary used in assisted reproductive technologies (ARTs) to increase the yields of mature oocytes. The possibility that patients with a history of failures or poor-responders may develop side-effects following these treatments is still debated. Epidemiological studies reported controversial results about pregnancy outcome and the risk of developing gynecological cancers. By using a mouse model, here we compared the ultrastructural features of fallopian tubes (FTs) obtained from mice undergoing or not (control, CTR) four (4R) and eight (8R) rounds of gonadotropin stimulation. Although the morphological characteristics of oviductal layers seemed unaffected by repeated treatments, dose-response ultrastructural alterations in the ampulla appeared in the 4R group and even more in the 8R group. The targets were oviductal ciliated (CCs) and non-ciliated (NCCs) cells, which showed damaged mitochondria and glycogen accumulations in the cytoplasm. The drastic reduction of CCs, evident after 4R, was supported by the absence of cilia. After 8R, glycogen granules were significantly reduced and massive degeneration of mitochondria, which appeared swollen and/or vacuolated, occurred in NCCs. Moreover, disintegrated mitochondria were found at the periphery of mitophagic vacuoles with evident signs of cristolysis. The morphometric analysis evidenced a significant increase in the density and frequency of damaged mitochondria after 4R and 8R. The absence of cilia, necessary to sustain oviductal transport of oocytes, spermatozoa and embryos, may originate from either mitochondrial dysfunction or glycogen consumption. These results suggest that repeated COH treatments could induce alterations impairing fertilization and embryo transport toward the uterus.

Debonding and Clean-Up in Orthodontics: Evaluation of Different Techniques and Micro-Morphological Aspects of the Enamel Surface

There is currently no consensus on the best way to remove adhesive remnants from teeth following debonding. The main objective of this study is to evaluate and compare the effectiveness of four adhesive resin removal (clean-up) techniques, performed with or without the use of an operative microscope. Forty human teeth were duplicated using an epoxy resin for impregnation. Brackets were bonded to teeth and debonded from teeth. Then, the samples were randomly divided into two equal groups-the naked eye group and the magnification group-and further subdivided into four equal subgroups, in order to compare the different techniques used for the clean-up. Each subgroup was formed of five natural teeth with the respective pre- and post-bonding replicas. Macro- and micro-analysis by means of a stereomicroscope and scanning electron microscopy evaluated, qualitatively and quantitatively, the adhesive remnant index and the damage index of the enamel. Overall, the magnification improved the removal of resins compared to the naked eye (p < 0.001), and the use of magnification constantly reduced resin residual and surface damage. Enamel damage and adhesive residual from the clean-up procedures represent an ascertained risk in orthodontics. The use of a magnification system improves the quality of debonding and clean-up techniques in a significant way.

Effects of a derivative of reutericin 6 and gassericin A on the biofilm of Streptococcus mutans in vitro and caries prevention in vivo

It is known that Streptococcus mutans (S. mutans) is the leading cariogenic pathogen. Recently, an increasing number of antimicrobial peptides (AMPs) have been brought into consideration as anti-caries agents. Here, we designed and synthesized an AMP derived from reutericin 6 and/or gassericin A, named LN-7, and explored its effect on biofilm of S. mutans UA159 in vitro and development of dental caries in vivo. Antibacterial assays showed that LN-7 was more active against S. mutans (3.2 μM) than many peptide-based agents, capable of killing other types of Streptococci in oral cavity. In addition, LN-7 presented fast killing kinetics, with more than 97% S. mutans killed within 5 min. The mechanism of the antimicrobial activity mainly lies on the disruption of bacterial membrane. Effects of LN-7 on the biofilm formation and the viability of preformed biofilm were quantified by crystal violet staining, which showed that LN-7 could effectively inhibit the biofilm accumulation of S. mutans. Moreover, the biofilm of S. mutans treated with LN-7 displayed notable changes in bacterial viability and morphology, observed by confocal laser scanning microscopy and scanning electron microscopy. In addition, topical oral treatment with LN-7 could suppress the development of dental caries in vivo, reducing the occurrence of severe dental lesion in a rodent model. These results reveal a new peptide-based agent as a topical treatment for dental caries, opening the door to clinical studies to explore its potential for caries prevention.

Pre-Implantation Mouse Embryos Cultured In Vitro under Different Oxygen Concentrations Show Altered Ultrastructures

Assisted Reproductive Technologies routinely utilize different culture media and oxygen (O2) concentrations to culture human embryos. Overall, embryos cultured under physiological O2 tension (5%) have improved development compared to embryos cultured under atmospheric O2 conditions (20%). The mechanisms responsible for this remain unclear. This study aimed to evaluate the effect of physiologic (5%) or atmospheric O2 (20%) tension on the microscopic ultrastructure of pre-implantation mouse embryos using Transmission Electron Microscopy (TEM). Embryos flushed out of the uterus after natural mating were used as the control. For use as the control, 2-cells, 4-cells, morulae, and blastocysts were flushed out of the uterus after natural fertilization. In vitro fertilization (IVF) was performed using potassium simplex optimized medium (KSOM) under different O2 tensions (5% and 20%) until the blastocyst stage. After collection, embryos were subjected to the standard preparative for light microscopy (LM) and TEM. We found that culture in vitro under 5% and 20% O2 results in an increase of vacuolated shaped mitochondria, cytoplasmic vacuolization and presence of multi-vesicular bodies at every embryonic stage. In addition, blastocysts generated by IVF under 5% and 20% O2 showed a lower content of heterochromatin, an interruption of the trophectodermal and inner cell mass cell membranes, an increased density of residual bodies, and high levels of glycogen granules in the cytoplasm. In conclusion, this study suggests that in vitro culture, particularly under atmospheric O2 tension, causes stage-specific changes in preimplantation embryo ultrastructure. In addition, atmospheric (20%) O2 is associated with increased alterations in embryonic ultrastructure; these changes may explain the reduced embryonic development of embryos cultured with 20% O2.

Preparation, Microstructure, Mechanical Properties and Biocompatibility of Ta-Coated 3Y-TZP Ceramic Deposited by a Plasma Surface Alloying Technique

A Ta coating has been successfully fabricated on the surface of zirconia polycrystals ceramic (3 mol% yttria, 3Y-TZP) by a plasma surface alloying technique. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results showed that a α-Ta coating with a continuous and compact surface morphology which consisted of a deposited layer with a thickness of 390 nm and a diffusion layer with a thickness of 200 nm covered the 3Y-TZP. Due to the effect of inhabitation the t→m transformation by the deposited Ta coating, the biaxial flexural strength caused by the phase transformation during hydrothermal aging is reduced e.g. p < 0.05 after 20 h and/or 100 h. In addition, the Ta coating shows non-cytotoxicity and improved proliferation ability of osteoblasts.

Combining culture and culture-independent methods reveals new microbial composition of halitosis patients' tongue biofilm

Background

Oral malodor is a very discomforting condition deriving from the presence of volatile sulfur compounds in the expired air. In halitosis of intraoral etiology, the volatile sulfur compounds are metabolic products of the oral microorganisms within the biofilm coating the tongue dorsum as well as other tissues in the oral cavity. The aim of this study was to characterize and compare the microbial composition of tongue biofilm in volunteers suffering from halitosis and healthy volunteers by means of both the culture method and culture‐independent cloning technique.

Results

A high bacterial variety (more than 80 different species) was detected using the combination of both methods. A distinct bacterial composition was revealed in the halitosis‐associated biofilms compared with the health‐associated biofilms. Actinomyces graevenitzii was shown to be significantly associated with the halitosis condition. The culture method identified 47 species, included Veillonella rogosae, never isolated from the tongue biofilm of halitosis patients so far. In the healthy condition, the culture‐dependent method showed that the most frequent species were Streptococcus parasanguinis among the aerobes and Veillonella spp. among the anaerobes. The culture‐independent cloning method detected more than 50 species. Streptococci, in particular S. mitis/oralis, S. pseudopneumoniae, and S. infantis as well as Prevotella spp., were found most frequently in halitosis patients. Streptococcus salivarius and Rothia mucilaginosa were found more frequently in the healthy condition.

Conclusions

The combination of the culture‐dependent and culture‐independent cloning techniques allowed for a widespread analysis of the tongue biofilm in halitosis patients. The results can support further pharmacological research for new antimicrobial agents and halitosis therapy strategies.

New Implant Macrogeometry to Improve and Accelerate the Osseointegration: An In Vivo Experimental Study

A new implant design with healing chambers in the threads was analyzed and compared with a conventional implant macrogeometry, both implants models with and without surface treatment. Eighty conical implants were prepared using commercially pure titanium (grade IV) by the company Implacil De Bortoli (São Paulo, Brazil). Four groups were performed, as described below: Group 1 (G1), traditional conical implants with surface treatment; group 2 (G2), traditional conical implants without surface treatment (machined surface); group 3 (G3), new conical implant design with surface treatment; group 4 (G4), new conical implant design without surface treatment. The implants were placed in the two tibias (n = 2 implants per tibia) of twenty New Zealand rabbits determined by randomization. The animals were euthanized after 15 days (Time 1) and 30 days (Time 2). The parameters evaluated were the implant stability quotient (ISQ), removal torque values (RTv), and histomorphometric evaluation to determine the bone to implant contact (%BIC) and bone area fraction occupancy (BAFO%). The results showed that the implants with the macrogeometry modified with healing chambers in the threads produced a significant enhancement in the osseointegration, accelerating this process. The statistical analyses of ISQ and RTv showed a significative statistical difference between the groups in both time periods of evaluation (p ≤ 0.0001). Moreover, an important increase in the histological parameters were found for groups G3 and G4, with significant statistical differences to the BIC% (in the Time 1 p = 0.0406 and in the Time 2 p < 0.0001) and the BAFO% ((in the Time 1 p = 0.0002 and in the Time 2 p = 0.0045). In conclusion, the result data showed that the implants with the new macrogeometry, presenting the healing chambers in the threads, produced a significant enhancement in the osseointegration, accelerating the process.

Effect of Sonic Application of Self-Adhesive Resin Cements on Push-Out Bond Strength of Glass Fiber Posts to Root Dentin

The aim of this study was to evaluate the influence of a sonic application of self-adhesive resin cements on the bond strength of glass fiber posts to root dentin. Eighty bovine incisors were randomly divided into eight groups (n = 10). Four self-adhesive resin cements were used-RelyX U200 (3M/ESPE), Bifix SE (Voco), seT PP (SDI), and Panavia SA (Kuraray). The cements were inserted into the root canal in two different modes-Centrix syringe (control) or with a sonic device (Sonic Smart). The roots were sectioned and taken to a universal test machine (Instron 3342) to perform the push-out test. The fracture pattern was evaluated by stereomicroscope and scanning electron microscope. The bond strength data were analyzed by two-way ANOVA and Tukey tests (α = 0.05). The interaction between the main factors was significant (p = 0.002). The sonic application increased the bond strength in comparison with the conventional application for the RelyX U200 (p < 0.001) and Bifix SE (p < 0.017) cements. However, for the seT PP and Panavia SA cements, the bond strength values did not differ significantly (p > 0.05). The fracture pattern showed adhesive at the interface between the luting cement and the dentin. Using a sonic device in the application of self-adhesive resin cement helpedpromote an increase in the bond strength for RelyX U200 and Bifix SE.

In Vitro Evaluation of Bacterial Adhesion and Bacterial Viability of Streptococcus mutans, Streptococcus sanguinis, and Porphyromonas gingivalis on the Abutment Surface of Titanium and Zirconium Dental Implants

Objective

To evaluate the in vitro adherence and viability of 3 bacterial species Streptococcus mutans (ATCC 25175), Streptococcus sanguinis (ATCC 10556), and Porphyromonas gingivalis (ATCC 33277) on the surfaces of dental implants of titanium, zirconium, and their respective fixing screws.

Methods

Two analysis groups were formed: group 1 with 3 titanium pillars and group 2 with 3 zirconium pillars, each with their respective fixing screws. Each of these groups was included in tubes with bacterial cultures of Streptococcus mutans (ATCC 25175), Streptococcus sanguinis (ATCC 10556), and Porphyromonas gingivalis (ATCC 33277). These samples were incubated at 37°C under anaerobic conditions. Bacterial adherence was assessed by measurement of the change in colony-forming units (CFU), and bacterial viability was evaluated with the colorimetric test of 3-(4,5-dimethylthiazol-2)-2,5 diphenyl tetrazolium bromide (MTT).

Results

The bacterial adhesion in the titanium abutments was higher for Streptococcus mutans (190.90 CFU/mL), and the viability was greater in Porphyromonas gingivalis (73.22%). The zirconium abutment group showed the highest adherence with Streptococcus mutans (331.82 CFU/mL) and the highest bacterial viability with the S. sanguinis strain (38.42%). The titanium fixation screws showed the highest adhesion with S. sanguinis (132.5 CFU/mL) compared to the zirconium fixation screws where S. mutans had the highest adhesion (145.5 CFU/mL). The bacterial viability of S. mutans was greater both in the titanium fixation screws and in the zirconium fixation screws 78.04% and 57.38%, respectively.

Conclusions

Our results indicate that there is in vitro bacterial adherence and viability in both titanium abutments and zirconium abutments and fixation screws for both. Streptococcus mutans is the microorganism that shows the greatest adherence to the surfaces of both titanium and zirconium and the fixing screws of the latter. On the contrary, bacterial viability is greater on the titanium abutments with P. gingivalis than on the zirconium abutments with S. sanguinis. With respect to the fixation screws, in both cases, the viability of S. mutans was greater with respect to the other bacteria. In general, the titanium abutments showed less adherence but greater bacterial viability.

Microbiological and SEM-EDS Evaluation of Titanium Surfaces Exposed to Periodontal Gel: In Vitro Study

Inflammatory diseases affecting the soft and hard tissues surrounding an implant represent a new challenge in contemporary implant dentistry. Among several methods proposed for the decontamination of titanium surfaces, the administration of topical 14% doxycycline gel seems to be a reliable option. In the present study, we evaluated the microbial effect of 14% doxycycline gel applied on titanium surfaces and exposed to human salivary microbes in anaerobic conditions. We also examined the composition of the exposed surfaces to assess the safe use of periodontal gel on titanium surfaces. Six anatase and six type 5 alloy titanium surfaces were used and divided into two groups: The test group and the positive control group. Both were cultured with human salivary samples in anaerobic conditions. On the test groups, 240 mg of periodontal gel was applied. The microbial assessment was performed with a colony-forming unit (CFU) count and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) to identify the species. The surface integrity was assessed using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS). The results demonstrated the microbial efficacy of the 14% doxycycline periodontal gel and its safe use on titanium surfaces. However, the SEM observations revealed the permanence of the gel on the titanium surfaces due to the physical composition of the gel. This permanence needs to be further investigated in vivo and a final polishing protocol on the titanium surface is recommended.

Osteoclastogenesis Behavior of Zirconia for Dental Implant

Zirconia is worth studying as an alternative to dental titanium implants to overcome the disadvantages of titanium. This study investigated the surface characteristics of the zirconia implant material and osteoclastogenesis responses on the surface compared with titanium. Yttrium oxide-stabilized 5% tetragonal zirconia polycrystalline specimens were manufactured, and osteoclast-precursor cells were cultured and differentiated into osteoclasts on the specimens. Surface shape, roughness, and chemical composition were evaluated. After culturing, cell morphologies and differentiation capacity were analyzed using tartrate-resistant acid phosphatase activity (TRACP). mRNA of two critical transcription factors, nuclear factor of activated T-cells 1 (NFATc1) and c-Fos were measured, and protein levels of NFATc1 and c-Fos were investigated. The zirconia specimens had rhomboid-like shapes with smooth surfaces and exhibited no difference in surface roughness compared to the titanium specimens. Morphologies of differentiated osteoclasts on both materials were similar. TRACP activity on the zirconia showed comparable results to that on the titanium. The mRNA value of NFATc1 on the zirconia was higher than that on the titanium at day four. The protein level of c-Fos was expressed thicker on the zirconia when compared to the titanium at day two. The results of this study suggest that zirconia material provides adequate osteoclastogenesis behaviors for dental implant use.

Sustained co-delivery of ibuprofen and basic fibroblast growth factor by thermosensitive nanoparticle hydrogel as early local treatment of peri-implantitis

Objective

The aims of this study were to 1) encapsulate ibuprofen (IBU) and basic fibroblast growth factor (bFGF) in a thermosensitive micellar hydrogel, 2) test the biological properties of this in situ drug delivery system, and 3) study the effect of hydrogel in promoting soft tissue healing after implant surgery and its anti-inflammatory function as an early local treatment of peri-implantitis.

Materials and methods

A thermosensitive micellar hydrogel was prepared from amphiphilic copolymer poly(ε-caprolactone-co-1,4,8-trioxa [4.6]spiro-9-undecanone)-poly(ethylene glycol)-poly(ε-caprolactone-co-1,4,8-trioxa [4.6]spiro-9-undecanone) (PECT) nanoparticles and tested in vitro using a scanning electron microscope, rheometer, UV spectrophotometer, HPLC, and transmission electron microscope.

Results

The bFGF + IBU/PECT hydrogel formed a stable, water-dispersible nanoparticle core shell that was injectable at room temperature, hydrogel in situ at body temperature, and provided sustained release of both hydrophilic and hydrophobic drugs. The hydrogel promoted the proliferation and adhesion of human gingival fibroblasts, upregulated the expression of adhesion factors such as vinculin proteins, and showed anti-inflammatory properties.

Conclusion

In situ preparation of IBU-and bFGF-loaded PECT hydrogel represents a promising drug delivery system with the potential to provide early local treatment for peri-implantitis.

Finite Element Analysis of Novel Separable Fixture for Easy Retrievement in Case with Peri-Implantitis

Peri-implantitis is a common complication following dental implant placement, which may lead to bone loss and fixation failure. With the conventional fixture, it is difficult to perfectly clear-up the infection. To solve this, we have designed a separable fixture of which the top part is replaceable. This study aimed to compare the structural and biomechanical stability of the separable and conventional fixture. A single surgical model corresponding to the first molar in a virtual mandible model and conventional/separable implants were reproduced to compare the biomechanical characteristics of the implants using finite element analysis (FEA). The loading condition was 200N preload in the first step, and 100N (Axial), 100N (15°), and 30N (45°) in the second step. The stress distribution on the cortical bone in the separable implant was lower than the conventional implant. In particular, the Peak von Mises Stress (PVMS) values of the separable implant under lateral load was found to be about twice as low as that of the conventional implant. In this study, we suggest that the separable implant has an equivalent biomechanical stability compared to the conventional implant, is easy to retrieve in the case of peri-implantitis, and has an excellent initial stability after the surgery when used in stage 2.

Short Versus Longer Implants in Mandibular Alveolar Ridge Augmented Using Osteogenic Distraction: One-Year Follow-up of a Randomized Split-Mouth Trial

The aim of this study was to evaluate the reliability of 6-mm-long implants compared with normal-length implants placed in a vertical augmented atrophic posterior mandible, supporting cemented single crowns. Thirty-six patients with bilateral posterior edentulous mandible and presenting a bone availability height less than 9 mm from the mandibular canal were enrolled in this study. Patient hemiarches were randomized to receive both 6-mm-long and normal-length implants (10 mm). The technique used for the vertical bone augmentation was the “sandwich” technique, using a bone substitute block as graft. The data outcomes at 1 year postloading follow-up were the loss of implants and complications. Eighty-six 6-mm-long implants and 84 normal implants were inserted. Five short implants and 13 normal implants were lost. In 28 patients, complications occurred, and in 21 cases, the complication was present on the side of the ridge vertical augmentation. From the statistical analysis, the association between the side of the ridge augmentation and the side of occurrence of the complication was statistically significant (P &lt; .05). The results from this trial suggest short implants can be preferred over vertical bone augmentation for the placement of longer implants in the rehabilitation of edentulous posterior mandibles. These initial results must be confirmed by larger and longer follow-ups of 5 years or more.