Bone Quantification Around Chitosan-Coated Titanium Dental Implants: A Preliminary Study by Micro-CT Analysis in Jaw of a Canine Model

Abstract

Surface treatments of Ti in the dental implant industry are performed with the aim of in-creasing its bioactivity and osseointegration capacity. Chitosan (Cht) is a polysaccharide that has been proposed as a promising biomaterial in tissue engineering and bone regeneration, due to its ability to stimulate the recruitment and adhesion of osteogenic progenitor cells. The aim of our preliminary study was to evaluate, by micro-computed tomography (micro-CT), the osseointegration and bone formation around Cht-coated implants and to compare them with conventional surface-etched implants (SLA type). Four im-plants (8.5 mm length × 3.5 mm Ø) per hemiarch, were inserted into the jaws of five dogs, divided into two groups: chitosan-coated implant group (ChtG) and control group (CG). Twelve weeks after surgery, euthanasia was performed, and sectioned bone blocks were obtained and scanned by micro-CT and two bone parameters were measured: bone in contact with the implant surface (BCIS) and peri-implant bone area (PIBA). For BCIS and PIBA statistically significant values were obtained for the ChtG group with respect to CG (p = 0.005; p = 0.014 and p < 0.001 and p = 0.002, respectively). The results, despite the limitations, demonstrated the usefulness of chitosan coatings. However, studies with larger sample sizes and adequate experimental models would be necessary to confirm the results.

The Importance of Chitosan Coatings in Dentistry

“…The released chlorhexidine was active against pathogens for 1 to 2 days (56%-99.5% inhibition), and its cell toxicity was observed on the first day after the application. The potential for local delivering antimicrobial substances was observed; its purpose was to inhibit bacterial growth without toxic effects to host cells/tissues -Release of tetracycline and chlorhexidine from the coatings were sufficient to stop bacterial growth for a few days, which can provide the necessary time for the normal host cells to stick to the implant surface and inhibit bacterial growth -Chitosan coatings may be used as a local drug delivery system for antibiotics Norowski et al [22] Chitosan coating (92.3% deacetylated polymer) -1% chitosan solution in 1% acetic acid was poured on ground titanium pins (rough ground titanium pins) covered with 3-aminopropyltriethoxysilane -As controls uncoated titanium pins and coated with calcium phosphate were used -In the tibias of 16 adult white male rabbits from New Zealand, 2 chitosan coated pins and 1 covered with phosphate calcium and uncoated were implanted -After 2, 4, 8 and 12 weeks histologically an angle healing and bone formation were assessed -Histological assessments of tissues in contact with chitosan coated spikes showed minimal inflammatory and typical response sequence of fibrous healing, bone formation followed by the development of the lamellar bone patterns of healing and development of bone connection with implant were assessed around chitosan-coated implants in a 12-week bone model, the tibia of the rabbit was similar to those in coated titanium pins and uncoated with calcium phosphate -Chitosan coatings can offer benefits in drug and growth factor delivery, compared with traditional ones, coated with calcium phosphate and uncoated implants -Chitosan coatings provide osseointegration of dental implants Bumgardner et al [23] chitosan coating -titanium implants coated with chitosan through dipping in the prepared polymer solution, then dried in a dryer at 25 • C in order to produce a uniform 50% relative humidity films to avoid cracking and shell deformation sterilized with gamma radiation -In the jaws of dogs, four implants were put and 12 weeks after the surgery euthanasia was performed excised bone blocks were taken and assessed for with the help of computed microtomography and two parameters of the bone were measured: bone contact with the implant surface (BCIS) and bone area around the implant (PIBA) -the results confirmed the suitability of the chitosan coatings on titanium surfaces in improving the osseointegration of dental implants López-Valverde et al [24] Chitosan coated liposomes -Liposomes prepared forLipid base: Egg-phosphatidylcholine, Nitrobenzoxadiazol-4yl-phosphocholine, fluorescent phospholipid labelled with fatty acid and lipids, egg Lα-phosphatidylglycerol or Dioleyl-trimethylammoniumpropane forming a lipid film by rotary evaporation of lipid solution in chloroform, then a phosphate film buffer was added (pH 6.8) -Size reduction was obtained by extrusion of double-layer polycarbonate membranes at size 200 nm -…”

Role of chitosan in titanium coatings. trends and new generations of coatings

“…Four of the in vivo studies reviewed (Bumgardner et al, 2007;Kung et al, 2011;Takanche et al, 2018;Zhang et al, 2020;López-Valverde et al, 2021a;López-Valverde et al, 2022) used coating formulations, in our opinion, of a certain complexity in terms of clinical applicability. The fifth study and sixth studies (López-Valverde et al, 2021a;López-Valverde et al, 2022) used a coating process described by Vakili et al (Vakili and Asefnejad, 2020) and Zhang et al (Zhang et al, 2019), with slight modifications, of easy applicability (Table 2). Grosso (Grosso, 2011) recommends immersion methods as a simple and inexpensive coating strategy, easily applicable in preclinical studies applicable in humans.…”

“…Cht as a titanium coating has been studied in depth by different researchers (Bumgardner et al, 2003a;Abarrategi et al, 2008), however, few in vivo studies have been published (Bumgardner et al, 2007;Kung et al, 2011;Takanche et al, 2018;Zhang et al, 2020;López-Valverde et al, 2021a;López-Valverde et al, 2022). On the other hand, when preparing Cht coatings for silanization and attachment to the Ti substrate, toxic Frontiers in Bioengineering and Biotechnology frontiersin.org reagents such as 3 isocyanatopropyltriethoxysilane and glutaraldehyde are used; moreover, these techniques involve complex processing that hinders the deposition of the coating and limits its clinical applicability.…”

Biomaterials science and surface engineering strategies for dental peri-implantitis management

“…Therefore, the inhibition of S. gordonii growth can effectively prevent colonization by P. gingivalis [ 251 ]. Moreover, chitosan-coated dental implants demonstrate the desired capacity to promote new bone formation, making chitosan a promising candidate for developing implants with both antibacterial and osteogenic properties [ 252 ].…”