Comparison of removal torques between laser-treated and SLA-treated implant surfaces in rabbit tibiae

An eight-year retrospective study on the clinical outcomes of laser surface-treated implants

PURPOSE

To retrospectively evaluate peri-implant bone loss and health status associated with the long-term use of laser surface-treated implants.

METHODS

For control study, total of 23 titanium ASTM F136 grade 23 implants were placed in the edentulous molar area of the mandible. When the Implant Stability Quotient (ISQ) ≥ 70 and insertion torque value (ITV) ≥ 35-50 Ncm at the insertion site, an immediate provisional restoration was connected to the implant within a week after surgery. The definitive restorations were placed 2 months after surgery for all implants. 13 implants were immediately loaded, while 10 implants were conventionally loaded. For comparative study, Radiographs were taken from third years for and then annually for the subsequent eight years to monitor marginal bone loss.

RESULTS

After eight year of implant installation, the average change in vertical bone loss was 0.009 mm (P < 0.001), while the average change in horizontal bone loss 8 year after implant placement was 0.026 mm (P < 0.001). The mean marginal bone loss was < 0.2 mm on average.

CONCLUSIONS

In this retrospective study, laser-treated implants exhibit a low rate of bone absorption around the implants.

Early Peri-Implant Bone Healing on Laser-Modified Surfaces with and without Hydroxyapatite Coating: An In Vivo Study

(1) Objective: The aim of this study was to assess the biological behavior of bone tissue on a machined surface (MS) and modifications made by a laser beam (LS) and by a laser beam incorporated with hydroxyapatite (HA) using a biomimetic method without thermic treatment (LHS). (2) Methods: Scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM/EDX) was performed before and after installation in the rabbit tibiae. A total of 20 Albinus rabbits randomly received 30 implants of 3.75 × 10 mm in the right and left tibias, with two implants on each surface in each tibia. In the animals belonging to the 4-week euthanasia period group, intramuscular application of the fluorochromes calcein and alizarin was performed. In implants placed mesially in the tibiofemoral joint, biomechanical analysis was performed by means of a removal torque (N/cm). The tibias with the implants located distally to the joint were submitted for analysis by confocal laser microscopy (mineral apposition rate) and for histometric analysis by bone contact implant (%BIC) and newly formed bone area (%NBA). (3) Results: The SEM showed differences between the surfaces. The biomechanical analysis revealed significant differences in removal torque values between the MSs and LHSs over a 2-week period. Over a 4-week period, both the LSs and LHSs demonstrated removal torque values statistically higher than the MSs. BIC of the LHS implants were statistically superior to MS at the 2-week period and LHS and LS surfaces were statistically superior to MS at the 4-week period. Statistical analysis of the NBA of the implants showed difference between the LHS and MS in the period of 2 weeks. (4) Conclusions: The modifications of the LSs and LHSs provided important physicochemical modifications that favored the deposition of bone tissue on the surface of the implants.

Osseointegration in additive-manufactured titanium implants: A systematic review of animal studies on the need for surface treatment

The objective of the systematic review is to find an answer to a question: "Do surface treatments on titanium implants produced by additive manufacturing improve osseointegration, compared to untreated surfaces?". This review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA 2020) and was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42022321351). Searches were performed in PubMed, Scopus, Science Direct, Embase, and Google Scholar databases on March 22nd, 2022. Articles were chosen in 2 steps by 2 blinded reviewers based on previously selected inclusion criteria: articles in animals that addressed the influence of surface treatments on osseointegration in implants produced by additive manufacturing. Articles were excluded that (1) did not use titanium surface, 2) that did not evaluate surface treatments, 3) that did not described osseointegration, 4) Studies with only in vitro analyses, clinical studies, systematic reviews, book chapters, short communications, conference abstracts, case reports and personal opinions.). 1003 articles were found and, after applying the eligibility criteria, 17 were used for the construction of this review. All included studies found positive osseointegration results from performing surface treatments on titanium. The risk of bias was analyzed using the SYRCLE assessment tool. Surface treatments are proposed to promote changes in the microstructure and composition of the implant surface to favor the adhesion of bone cells responsible for osseointegration. It is observed that despite the benefits generated by the additive manufacturing process in the microstructure of the implant surface, surface treatments are still indispensable, as they can promote more suitable characteristics for bone-implant integration. It can be concluded that the surface treatments evaluated in this systematic review, performed on implants produced by additive manufacturing, optimize osseointegration, as it allows the creation of a micro-nano-textured structure that makes the surface more hydrophilic and allows better contact bone-implant.

LASER as a tool for surface modification of dental biomaterials: A review

In recent years, the application of lasers for modifying the surface topography of dental biomaterials has received increased attention. This review paper aims to provide an overview of the current status on the utilization of lasers as a potential tool for surface modification of dental biomaterials such as implants, ceramics, and other materials used for restorative purposes. A literature search was done for articles related to the use of lasers for surface modification of dental biomaterials in English language published between October 2000 and March 2023 in Scopus, Pubmed and web of science, and relevant articles were reviewed. Lasers have been mainly used for surface modification of implant materials (71%), especially titanium and its alloys, to promote osseointegration. In recent years, laser texturing has also emerged as a promising technique to reduce bacterial adhesion on titanium implant surfaces. Currently, lasers are being widely used for surface modifications to improve osseointegration and reduce peri-implant inflammation of ceramic implants and to enhance the retention of ceramic restorations to the tooth. The studies considered in this review seem to suggest laser texturing to be more proficient than the conventional methods of surface modification. Lasers can alter the surface characteristics of dental biomaterials by creating innovative surface patterns without significantly affecting their bulk properties. With advances in laser technology and availability of newer wavelengths and modes, laser as a tool for surface modification of dental biomaterials is a promising field, with excellent potential for future research.

The Affinity of Human Fetal Osteoblast to Laser-Modified Titanium Implant Fixtures

Introduction:

Implant surface modification methods have recently involved laser treatment to achieve the desired implant surface characteristics. Meanwhile, surface modification could potentially introduce foreign elements to the implant surface during the manufacturing process.

Objectives:

The study aimed to investigate the surface chemistry and topography of commercially available laser-modified titanium implants, together with evaluating the cell morphology and cell adhesion of human fetal osteoblast (hFOB) seeded onto the same implants.

Method:

Six (6) samples of commercially available laser-modified titanium implants were investigated. These implants were manufactured by two different companies. Three (3) implants were made from commercially pure grade 4 Titanium (Brand X); and three were made from grade 5 Ti6Al4V (Brand Y). The surface topography of these implants was analyzed by scanning electron microscope (SEM) and the surface chemistry was evaluated with electron dispersive x-ray spectroscopy(EDS). Human fetal osteoblasts were seeded onto the implant fixtures to investigate the biocompatibility and adhesion.

Results & Discussion:

Brand X displayed dark areas under SEM while it was rarely found on brand Y. These dark areas were consistent with their organic matter. The hFOB cell experiments revealed cell adhesion with filopodia on Brand X samples which is consistent with cell maturation. The cells on Brand Y were morphologically round and lacked projections, one sample was devoid of any noticeable cells under SEM. Cell adhesion was observed early at 48 hrs in laser-irradiated titanium fixtures from both the brands.

Conclusion:

The presence of organic impurities in Brand X should not be overlooked because disruption of the osseointegration process may occur due to the rejection of the biomaterial in an in-vivo model. Nevertheless, there was insufficient evidence to link implant failure directly with carbon contaminated implant surfaces. Further studies to determine the toxicity of Vanadium from Ti6Al4V in an in-vivo environment should indicate the reason for different cell maturation.

Clinical outcome of immediately and early loaded implants with laser treated surface: a 3-year retrospective study

PURPOSE

The marginal bone loss of implants with laser treated surface was investigated after six weeks of loading after implant installation to the mandible molar area.

MATERIALS AND METHODS

A total of 23 implants were placed in the edentulous molar area of the mandible: 13 implants were immediately loaded and 10 implants were early loaded. The implants used were made of titanium grade 23, screw shaped, 4.2 mm in diameter, and 10 mm in length. Patients were evaluated with resonance frequency analysis at implant fixture installation and 1, 2 (final prosthesis installation), 3, 5, 8, and 14 months later. X-rays were taken at 2 months after fixture installation and 1, 2, 3 years after to measure the marginal bone loss.

RESULTS

The mean ISQ value measured at the implant installation was over 70 at all-time points. The average of marginal bone loss was average 0.33 mm.

CONCLUSION

Immediate implant loading for laser treated implants would be possible.

Biomechanical evaluation of laser-etched Ti implant surfaces vs. chemically modified SLA Ti implant surfaces: Removal torque and resonance frequency analysis in rabbit tibias

PURPOSE

To compare osseointegration and implant stability of two types of laser-etched (LE) Ti implants with a chemically-modified, sandblasted, large-grit and acid-etched (SLA) Ti implant (SLActive(®), Straumann, Basel, Switzerland), by evaluating removal torque and resonance frequency between the implant surface and rabbit tibia bones. We used conventional LE Ti implants (conventional LE implant, CSM implant, Daegu, Korea) and LE Ti implants that had been chemically activated with 0.9% NaCl solution (LE active implant) for comparison with SLActive(®) implants

MATERIALS AND METHODS

Two types of 3.3×8mm laser-etched Ti implants - conventional LE implants and LE active implants were prepared. LE implants and SLActive(®) implants were installed on the left and right tibias of 10 adult rabbits weighing approximately 3.0kg LE active implants and SLActive(®) implants were installed on the left and right tibias of 11 adult rabbits. After installation, we measured insertion torque (ITQ) and resonance frequency (ISQ). Three weeks (LE active) or 4 weeks (conventional LE) after installation, we measured removal torque (RTQ) and ISQ.

RESULTS

In the conventional LE experiment, the mean ITQ was 16.99±6.35Ncm for conventional LE implants and 16.11±7.36Ncm for SLActive(®) implants (p=0.778>0.05). After 4 weeks, the mean of RTQ was 39.49±17.3Ncm for LE and 42.27±20.5Ncm for SLActive(®) (p=0.747>0.05). Right after insertion of the implants, the mean ISQ was 74.8±4.98 for conventional LE and 70.1±9.15 for SLActive(®) implants (p=0.169>0.05). After 4 weeks, the mean ISQ was 64.40±6.95 for LE and 67.70±9.83 for SLActive(®) (p=0.397>0.05). In the LE active experiment, the mean ITQ was 16.24±7.49Ncm for LE active implants and 14.33±5.06Ncm for SLActive(®) implants (p=0.491>0.05). After 3 weeks, the mean RTQ was 39.25±16.41Ncm for LE active and 41.56±10.41Ncm for SLActive(®) implants (p=0.698>0.05). Right after insertion of the implants, the mean ISQ was 58.64±10.51 for LE active implants and 53.82±15.36 for SLActive(®) implants (p=0.401>0.05). After 3 weeks, the mean ISQ was 63.82±5.88 for LE active and 66.27±6.53 for SLActive(®) (p=0.365>0.05).

CONCLUSION

We observed no significant differences in biomechanical bond strength to bone or implant stability in bone between the conventional LE Ti implant surface and the surface of the SLActive(®) implant or between the chemically activated LE Ti implant surface and the surface of the SLActive(®) implant during the early stage of osseointegration.