CN119792485B - Antibacterial repair-promoting hydrogel dressing and preparation method thereof - Google Patents

Abstract

The application belongs to the technical field of dental dressing, and particularly relates to a bacteriostatic repair-promoting hydrogel dressing and a preparation method thereof. The application discovers for the first time that the compound A has remarkable antibacterial activity on common bacteria in the oral cavity, and still has antibacterial activity after the compound A is prepared into temperature-sensitive hydrogel dressing. And the implant is injected around the implant, so that the reduction of alveolar bones can be prevented, the vertical bone regeneration at the surrounding part of the implant is stimulated, the bone quantity is increased to improve the stability of the implant, the fusion of wounds between the alveolar bones and the implant is finally promoted, and the service life of the implant is prolonged.

Description

Antibacterial repair-promoting hydrogel dressing and preparation method thereof

Technical Field

The invention belongs to the technical field of dental dressing, and particularly relates to a bacteriostatic repair-promoting hydrogel dressing and a preparation method thereof.

Background

Loss of teeth/dentition is the most important group of diseases in oral clinical work. The loss of natural teeth can degrade the normal chewing function of the oral and jaw system, and simultaneously bring about the change of facial appearance, thereby affecting the beauty. The instability and the loss of the occlusion relationship can cause disorder and even pathological changes of the temporomandibular joint part, seriously affect the life quality of patients and influence the physiological and psychological functions. The implant denture restoration can greatly improve the chewing efficiency after restoration treatment under the condition of not damaging adjacent teeth, has the characteristics of high comfort level, durability and the like which are not possessed by the conventional restoration methods, and becomes a preferential choice in the tooth loss restoration treatment process more and more.

The origin of modern dental implant repair techniques can be traced back to the middle 50-60 s of the last century, and the Branemark professor from sweden and his colleagues have first proposed bone-joining phenomena and pure titanium implants, i.e. after the pure titanium implant is implanted in the body and healed, a tightly bonded interface is created between the pure titanium implant and the surrounding bone tissue, and a direct structural and functional connection is provided. This physiological phenomenon is also the basis for the implant to remain stable and function in bone tissue. Over long-term development, the variety of oral implants has tended to be diversified. The implant can be divided into a one-stage implant and a two-stage implant according to different implantation time and modes, and can be divided into an intraosseous implant, a zygomatic implant and the like according to implantation sites of the implant, and can be divided into a columnar implant, a conical implant, a root-shaped implant and the like according to different general forms of the implant.

As an implantable medical device, implant materials should have high biocompatibility and exhibit specific physiological functions on the basis of good biosafety. In addition, the material has excellent mechanical and corrosion resistance aiming at the special physical and chemical environment in the oral cavity, and can meet the practical application. In particular to the clinical situation that the jaundice has smaller mandible quantity and the planting space is insufficient than those of European americans and a large amount of implants with narrow diameters are needed, and the novel implant material should meet the characteristics of high (mechanical) strength, low (elastic) modulus and narrow diameter. Such clinical demands also put new demands and directions for development and research of implant materials.

Pure titanium material is used as a basic stone in the development process of the implant and is the main stream material of the current implant system. Along with the progress of material science and processing technology, various materials with good performance are developed and utilized to further improve the comprehensive performance of the implant, the application range and the application scene of the implant are enlarged, and the method has important research significance and practical value. Currently, the novel implant materials are endlessly layered and mainly comprise metal materials, ceramic materials, organic polymer materials and the like, wherein the metal materials are represented by pure titanium and alloy thereof. These materials have different biological and mechanical properties.

Titanium and titanium alloy are used as biological inert materials to face the challenge of insufficient osteoinductive capacity in clinical application, and the osteointegration performance of the titanium and titanium alloy is required to be improved by a multidimensional technology. The construction of the micro-nano topological structure on the surface of the implant can simulate the three-dimensional pore characteristics of natural bone tissue, promote the directional migration and mineralization deposition of osteoblasts, and the related technology is verified ‌ in the high-precision part processing in the field of aviation. The hydroxyapatite coating is formed by a plasma spraying technology, so that not only is the bone conductivity of the implant enhanced, but also an osteogenic signal path can be activated by calcium-phosphorus ion gradient release, and the technical principle has similarity ‌ with the preparation technology of the spacecraft thermal protection coating.

The chemical grafting technology can fix bioactive molecules on the titanium-based surface, for example, arginine-glycine-aspartic acid (RGD) polypeptide sequences are introduced, cell adhesion behavior is regulated by specifically recognizing integrin receptors, and the molecular modification strategy has been successfully applied to the treatment of flexible sensor substrates.

The temperature-sensitive hydrogel system realizes gelation packaging at physiological temperature by utilizing the phase change characteristics of temperature-sensitive materials such as poly-N-isopropyl acrylamide and the like, and precisely controls the slow release kinetics of bone growth promoters such as Bone Morphogenetic Protein (BMP) and the like, wherein the controlled release mechanism has technical commonality ‌ with the intelligent response characteristics of high-end engineering plastics.

The temperature sensitive hydrogel system can bring about a number of clinical advantages and provide a suitable environment for local bone regeneration around the implant. Because the temperature sensitive hydrogel system has high water content, bone growth promoters such as BMP-2 and the like can be easily loaded in a solution state by a simple mixing method. The system has a temperature-dependent gelling property, so that it can be conveniently applied to a human body at room temperature. In addition, it requires neither surgery nor additional external factors to form the hydrogel. This temperature sensitive and injectable property is very convenient for the patient. In addition, the hydrophilic environment and high porosity of the hydrogel system facilitates cell infiltration, vascularization and subsequent bone regeneration.

The particular physiological structure and environment of the oral cavity makes oral administration difficult. Thus, there is an urgent need for a pharmaceutical carrier to address the problem of oral administration. The polyoxyethylene-polyoxypropylene copolymer (poloxamer 407) or carbomer can form a thermo-sensitive biogel with good mechanical properties and mucoadhesive properties. Such a biogel may be designed as a drug supply platform for an oral implantable drug delivery system. Topical administration is commonly used to treat periodontitis, oral eruptions, and other oral diseases. The main advantages of this drug delivery approach are that it allows for the delivery of the bioactive agent directly to the affected site, maintains the desired drug concentration for a considerable period of time, and ensures good residence at the site of administration. Below the sol-gel transition temperature, the flowability and compression characteristics of the formulation are very low. In contrast, above the sol-gel transition temperature, these formulations exhibit a wide range of viscoelastic, mechanical and mucoadhesive properties, which will facilitate their application to specific sites in the oral cavity. The high elasticity and mucoadhesion will make poloxamer 407 containing formulations an effective platform for controlling the local drug delivery in the mouth. At present, temperature-sensitive gel dressings have been widely used for treating various periodontal diseases, and the formulation variety is wide. For example, research into the treatment of periodontitis with moxifloxacin hydrochloride in situ gel, injectable in situ curcumin gel for the treatment of periodontal pockets, thermo-sensitive gel for the treatment of oral herpes infections, and clinical cases of thermo-sensitive gel as a stent encapsulation system.

The Xu Wenfang teaching of Shandong university conducted research on L-isoserine tripeptide derivatives as aminopeptidase inhibitors to obtain a series of L-isoserine tripeptide derivatives, and the related research results are published in Journal of Enzyme Inhibition AND MEDICINAL CHEMISTRY, entitled Design,synthesis and biological evaluation of novel L-isoserine tripeptide derivatives as aminopeptidase N inhibitors,, and the novel L-isoserine tripeptide derivatives are used as aminopeptidase N inhibitors for designing, synthesizing and evaluating biological activity.

The article extends around the research of novel L-isoserine tripeptide derivatives as aminopeptidase N (APN) inhibitors, covers various contents such as design, synthesis, biological activity evaluation and the like, and aims to develop novel anticancer drugs. The compound 14b is used as a lead in the research, and the novel L-isoserine tripeptide derivative is designed and synthesized. Other target compounds except compound 16j were inhibitory. In-vitro APN inhibitory Activity Compound 16l has the strongest inhibitory ActivitySlightly better thanTyrosine groups may enhance interactions with APN through hydrogen bonding, with the R1-position phenyl group being more beneficial than benzyl to increase activity. The series 2 compounds have similar inhibitory activity to the series 1 compounds, but the water solubility is significantly reduced. The results of the cell level experiment are substantially consistent with the enzyme level experiment, but the inhibition activity of compound 16l on a549 cells is weak, possibly related to the difference of the binding characteristics of APN in different species.

In terms of antiproliferative activity, some compounds showed similar or even better antiproliferative effects on different tumor cell lines than Bestatin, but compound 16l did not show outstanding activity in antiproliferative experiments. And compounds which perform well in an APN inhibition experiment, the antiproliferative activity on cells which express APN in high levels does not protrude from cells which express APN in low levels, suggesting that the antiproliferative mechanism of these compounds may be different from the mechanism of APN inhibition. Through molecular docking, it was found that the binding pattern of compounds 16L and Bestatin is similar, the L-isoserine moiety thereof coordinates to the zinc ion of APN, the phenyl moiety of phenylalanine and tyrosine residues inserts into the S1 pocket of APN, the leucine moiety inserts into the S1 'pocket and forms hydrogen bonds with multiple amino acid residues, enhancing binding affinity, while chloramphenicol amine residues of compound 16j do not enter the S1' pocket, resulting in a difference in activity.

16J synthesized in the article, chemical formulaMolecular weight 426.18, chemical name 2- (3-amino-2-hydroxypropyl-amido) -3-hydroxy-3- (4-nitrophenyl) propionylleucine, chemical structure is as follows:

。

however, there is no report on other activities or uses of the 16j structure (hereinafter simply referred to as compound a) described above in the prior literature and patent.

Disclosure of Invention

As an stomatologist, the inventors have made intensive studies on a dressing for promoting local bone regeneration around an implant. The compound A can be used as a main component of a dressing to prepare a temperature-sensitive hydrogel dressing for promoting local bone regeneration around an implant, so that after implantation, repairing of an alveolar bone wound is promoted, and the compound A has remarkable antibacterial effect and remarkable antibacterial effect on common bacteria in an oral cavity.

The application discloses the application of the compound A in preparing a dressing for promoting local bone regeneration around an implant for the first time.

The chemical structure of the compound A is as follows:

。

The implant material is one of titanium, titanium alloy and ceramic.

The implant material is one of titanium, titanium alloy and ceramic with surface modified.

The application further discloses the use of compound a for the preparation of a dressing for inhibiting bacterial growth around an implant.

The dressing is a hydrogel dressing.

The mass percentage concentration of the compound A in the dressing is 0.1% -5%.

The mass percentage concentration of the compound A in the dressing is 1.5%.

The mass percentage concentration of the compound A in the dressing is 2%.

The dressing is a temperature sensitive hydrogel dressing.

The temperature sensitive hydrogel dressing is injected around the implant through an injector, and plays roles of inhibiting bacteria, promoting growth of alveolar bone, promoting wound fusion between the alveolar bone and the implant and prolonging service life of the implant.

Poloxamer 407 is used as a hydrogel matrix in the temperature-sensitive hydrogel dressing.

The preparation method of the temperature-sensitive hydrogel dressing comprises the following steps:

1) Dissolving a compound A in phosphate buffer solution;

2) Adding poloxamer 407 into the solution obtained in the step 1), stirring while adding, and adding into phosphate buffer solution to fix the volume after the poloxamer 407 is completely dissolved;

3) And 2) taking the gel solution obtained in the step 2), subpackaging the gel solution into penicillin bottles, adding rubber plugs, and rolling an aluminum cover to obtain the gel.

The application has the beneficial effects that the compound A has remarkable antibacterial activity on common bacteria in the oral cavity for the first time, and still has antibacterial activity after being prepared into the temperature-sensitive hydrogel dressing. And the implant is injected around the implant, so that the reduction of alveolar bones can be prevented, the vertical bone regeneration at the surrounding part of the implant is stimulated, the bone quantity is increased to improve the stability of the implant, the fusion of wounds between the alveolar bones and the implant is finally promoted, and the service life of the implant is prolonged.

Abbreviation description:

TSB medium-trypticase Soytone liquid Medium (TRYPTICASE SOY BROTH, TSB);

BHI medium-brain heart infusion medium ‌ (‌ Brain Heart Infusion Medium ‌);

RPMI1640 medium, no. 1640 medium prepared by Rockwell Pake souvenir institute (Roswell Park Memorial Institute, RPMI);

MH medium ‌ Mueller-Hinton medium.

Drawings

FIG. 1 promotion of alveolar osteogenesis around titanium implant by example 3-5 hydrogel dressing and comparative dressing (n=4)

FIG. 2 effect of the hydrogel dressings of examples 3-5 and the comparative examples on the vertical growth height of bone around titanium implant (n=4)

Detailed Description

The present invention is further illustrated below with reference to specific examples, which are not intended to limit the invention in any way. Unless specifically stated otherwise, the reagents, methods and apparatus employed in the present invention are those conventional in the art.

Reagents and materials used in the following examples are commercially available unless otherwise specified.

EXAMPLE 1 preparation of Compound A hydrogel dressing

1) 0.1G of Compound A was dissolved in 70ml of phosphate buffer (pH 7.4,100 mM).

2) Adding 15.0g of poloxamer 407 into the solution obtained in the step 1), stirring while adding, adding into phosphate buffer (pH 7.4,100 mM) after the poloxamer 407 is completely dissolved, and fixing the volume to 100ml;

3) And (3) taking the gel solution obtained in the step (2), sub-packaging the gel solution into penicillin bottles, adding rubber plugs into each bottle, and rolling an aluminum cover to obtain the penicillin bottle.

Comparative example:

a 15% poloxamer 407 hydrogel dressing was prepared as a comparative example, following the preparation procedure of example 1, without compound a.

EXAMPLES 2-6 preparation of hydrogels of Compound A at different concentrations

According to the preparation process of example 1, only the addition amount of the compound A in the step 1) was changed, and hydrogel dressings containing 0.5%, 1.0%, 1.5%, 2.0% and 5.0% were prepared in order, respectively, and were defined as hydrogel dressings of examples 2 to 6 in order.

Example 7 antibacterial experiments on Compound A (see Chinese patent CN 113679632B)

7.1, Experimental methods

(1) Strain culture

Candida albicans Candida albicans ATCC SC, 5314 in RPMI 1640 medium, 37 ℃ and humidity 80%,Is incubated under the condition of (2);

Staphylococcus aureus Staphylococcus aureus ATCC 6538 in TSB medium, 37C, Is incubated under the condition of (2);

methicillin-resistant staphylococcus aureus metacilin-RESISTANT STAPHYLOCOCCUS AUREUS 18908 (MRSA 18908) in TSB medium at 37C, Is incubated under the condition of (2);

porphyromonas gingivalis GINGIVALIS ATCC 33277 is cultured under strict anaerobic conditions at 37 ℃ by adding hemin (haemin, 5 μg/mL) and vitamin K (menadione, 1 μg/mL) into BHI medium;

streptococcus mutans Streptococcus mutans CLARKE ATCC UA159 was cultured on brain heart infusion agar medium at 37deg.C, Culturing under the condition;

Streptococcus sanguis Streptococcus sanguis ATCC 10556 in brain heart infusion agar medium at 37deg.C, Culturing under the condition.

(2) Sample of

Compound a was dissolved in distilled water to a concentration of 10mg/mL, and 20mL was prepared in total and cooled in a 4 ℃ refrigerator for use.

(3) Determination of Minimum Inhibitory Concentration (MIC)

Compound a was assayed for Minimal Inhibitory Concentration (MIC) against different microorganisms by a mini-broth double dilution method, with reference to the Clinical and Laboratory Standardization Institute (CLSI) specifications. The method is a recognized effective method of Clinical and Laboratory Standardization Institute (CLSI), has wide and common application range, can rapidly realize the detection of the interaction effect of the medicine in a short time, can obtain a reliable conclusion through further analysis of experimental data, and has stable result and high repeatability.

For candida albicans ATCCSC5314, the test strain was brought to concentration using physiological salineThereafter, the bacterial suspension is diluted in RPMI1640 medium toThe strain liquid to be tested is prepared. 200. Mu.L of the bacterial liquid to be tested is added into the first hole of the flat bottom 96-well plate, and 100. Mu.L of the bacterial liquid to be tested is added into each hole. Adding 2 mu L of a compound stock solution to be tested (the concentration of the compound A in the hole is 100 mu g/mL) into the first hole, blowing and mixing uniformly, taking 100 mu L of a uniform suspension, adding the second hole, blowing and mixing uniformly, repeating until the last hole, and discarding the redundant bacterial solution. The MIC was defined as the minimum drug concentration that could inhibit microbial growth by visual observation when the 96-well plate was incubated at 37 ℃ for 24 hours. The experiment was repeated in three groups and econazole was selected as a positive control.

For staphylococcus aureus ATCC 6538 and methicillin-resistant staphylococcus aureus 18908, the tested strain was brought to concentration using MH mediumPreparing the strain liquid to be tested. 200. Mu.L of the bacterial liquid to be tested is added into the first hole of the flat bottom 96-well plate, and 100. Mu.L of the bacterial liquid to be tested is added into each hole. Adding 2 mu L of a compound stock solution to be tested (the concentration of the compound A in the hole is 100 mu g/mL) into the first hole, blowing and mixing uniformly, taking 100 mu L of a uniform suspension, adding the second hole, blowing and mixing uniformly, repeating until the last hole, and discarding the redundant bacterial solution. The 96-well plate was set at 37C,Incubation for 24 hours under conditions, MIC was defined as the minimum drug concentration that could inhibit microbial growth observed visually. The experiment was repeated in three groups and vancomycin was used as a positive control.

For Streptococcus mutans ATCC UA159 and Streptococcus sanguis ATCC 10556, the test strain was brought to a concentration using BHI mediumPreparing the strain liquid to be tested. 200. Mu.L of the bacterial liquid to be tested is added into the first hole of the flat bottom 96-well plate, and 100. Mu.L of the bacterial liquid to be tested is added into each hole. Adding 2 mu L of a compound stock solution to be tested (the concentration of the compound A in the hole is 100 mu g/mL) into the first hole, blowing and mixing uniformly, taking 100 mu L of a uniform suspension, adding the second hole, blowing and mixing uniformly, repeating until the last hole, and discarding the redundant bacterial solution. The 96-well plate was set at 37C,Incubation for 24 hours under conditions, MIC was defined as the minimum drug concentration that could inhibit microbial growth observed visually. The experiment was repeated in three groups and vancomycin was selected as a positive control.

To Porphyromonas gingivalis ATCC33277, a test strain was adjusted to a concentration of 1. Mu.g/mL by adding chlorhexidine (5. Mu.g/mL) and vitamin K (1. Mu.g/mL) using BHI mediumPreparing the strain liquid to be tested. 200. Mu.L of the bacterial liquid to be tested is added into the first hole of the flat bottom 96-well plate, and 100. Mu.L of the bacterial liquid to be tested is added into each hole. Adding 2 mu L of a compound stock solution to be tested (the concentration of the compound A in the hole is 100 mu g/mL) into the first hole, blowing and mixing uniformly, taking 100 mu L of a uniform suspension, adding the second hole, blowing and mixing uniformly, repeating until the last hole, and discarding the redundant bacterial solution. 96-well plates were incubated at 37 ℃ for 24 hours under strictly anaerobic conditions, MIC being defined as the minimum drug concentration that could inhibit microbial growth observed visually. The experiment was repeated in three groups and chlorhexidine was selected as a positive control.

7.2 Results of antibacterial experiments

TABLE 1 minimum inhibitory concentration MIC values for Compound A

。

Table 1 shows the antibacterial results of the compound A on common oral bacteria, and from the results in the table, the compound A has remarkable antibacterial effects on candida albicans, staphylococcus aureus, MRSA, streptococcus mutans, streptococcus sanguinis and porphyromonas gingivalis, and the MIC value is between 12.5 and 50 mug/mL.

Example 8 gelation of examples 1-6 and comparative temperature sensitive hydrogel dressing

When the temperature changes, the aqueous solution of poloxamer 407 hydrogel undergoes a thermosensitive phase change. The solution remained in solution at room temperature. After the temperature rises, gelation occurs, and the gel viscosity increases sharply. The viscosities of the hydrogel dressings obtained in the comparative examples and examples 1 to 6 were all greatly changed when the temperature was increased to 37 ℃. Gel formation under body temperature conditions was confirmed by tilting.

In addition, the supported drug may change the hydrophobic/hydrophilic ratio, and thus the gelation properties may be affected by the supported drug. Thus, the loading of compound a affects the temperature sensitive properties of poloxamer 407 hydrogel. In order to confirm the gelation properties of poloxamer 407 hydrogels loaded with compound a at body temperature, the gel permeation temperatures of the hydrogel dressings obtained in examples 1to 6 and comparative example were studied. The results show that the gel temperature of the hydrogel dressings obtained in examples 1-6 did not significantly change compared to the poloxamer 407 hydrogel without compound a (comparative).

The hydrogel dressings obtained in examples 1 to 6 and comparative example were gradually warmed up (warming rate was 0.5 ℃ per minute) with continuous stirring (rotational speed was 100 rpm). The temperature was set by means of a thermostatic water bath and the temperature inside the sample was controlled using a precision thermometer (precision + -0.1 deg.c). When the stirrer (length 25 mm, diameter 6 mm) stopped moving due to gelation, the temperature shown at this time was recorded as the temperature at which the solution was converted into gel, i.e., the gelation temperature.

Table 2 gel temperatures of the hydrogel dressings obtained in examples 1 to 6 and the hydrogel dressing of comparative example

。

EXAMPLE 9 Single injection of the hydrogel dressings from examples 1-6 and comparative example in situ bone formation studies

Male C57BL/6 mice of 18-20 g in weight at 6 weeks of age were randomly divided into eight different groups of 5 animals each. The hydrogel dressings and physiological saline obtained in examples 1 to 6 and comparative example were respectively administered. After shaving each mouse, 200 μl of hydrogel dressing or saline of different formulation was injected subcutaneously in the back. After 8 weeks, mice were sacrificed by carbon dioxide asphyxiation and specimens of each group were collected at and around the injection site. Samples were carefully removed, fixed in 10% neutral buffered formalin for 24 hours, and then transferred to 70% ethanol.

The osteogenic capacity of the hydrogel dressings obtained in examples 1-6 and comparative example was evaluated in situ by a single injection.

Eight weeks after injection, the bone produced was evaluated by soft X-ray and micro-computed tomography (μ -CT). Irregularly spherical osteogenesis was observed at the injection site.

Increased bone tissue volume = bone tissue volume observed for the administration of dressing group-bone tissue volume observed for the control group per cubic millimeter, as per the formula. Experimental data are as follows:

table 3 increased bone tissue volume in each group of experimental mice

。

As the concentration of compound a in the hydrogel dressing increased, the bone tissue formed became progressively larger, but after the concentration increased to 2%, i.e., when the concentration increased to 5%, the bone tissue formed did not significantly increase compared to the hydrogel dressing with the concentration of 2%. No bone-like tissue was observed in the control group.

Eight weeks after injection, all the hydrogel formed completely disappeared. No inflammatory response was observed in any of the experimental groups. These non-toxic reactions indicate that the hydrogel dressings obtained in examples 1-6 have excellent biocompatibility. Surrounding cells can infiltrate well into the hydrogel dressing, and sustained release of compound a from the hydrogel dressing aids in cell survival, differentiation and bone tissue formation.

Example 10 experiment of oral titanium implant for beagle

10.1 Implantation of titanium implant:

all procedures were performed under general and local anaesthesia under sterile conditions using cimetidine hydrochloride, cefazolin sodium, dexmedetomidine, a mixture of telitamine/zolazepam. Isoflurane and 100% pure oxygen were used to maintain anesthesia.

After extracting the mandibular teeth from the first premolars to the first molars of the two beagle dogs, the incision site was sutured with 4-0 nylon wire. After 8 weeks, 4 bone defects 3mm in height and 16mm in length were made on the left and right mandibles, respectively, using a water-cooled rotary dental drill. A total of 16 titanium implants were implanted, 2 per bone defect and 8 per dog. The distance between the implants was about 4mm, and the upper 4mm of the implant was exposed outside the alveolar bone. Control (four implants) were each used with 250 μl of the hydrogel dressing prepared in the comparative example at the bone defect, and immediately after gelation, the wound was sutured with 4-0 nylon wire. The experimental groups were treated with 250 μl of the compound a hydrogel dressing prepared in examples 3-5, four implants per example group, respectively, at the bone defect site where the remaining twelve implants were located. Immediately after gelling the polymer solution by body temperature, the wound was sutured with 4-0 nylon wire.

Amoxicillin and meloxicam were orally administered twice daily for 7 consecutive days after surgery, the latter once daily. During the experiment, the oral cavity was rinsed daily with 2% chlorhexidine gluconate to maintain oral hygiene.

10.2 Clinical observations

The operation process of the animal is smooth. Animals were checked daily for health status, dogs were normal in activity and the healing process was natural. Tooth extraction, alveolar ridge trimming, and placement of titanium implants were completed according to the study protocol.

The experimental design is summarized in table 4. Defects of 3mm height and 4 x 16mm in area were made on the mandible of beagle dogs using a water-cooled rotary dental drill. After placement of the titanium implant, freshly prepared example 3-5 hydrogel dressing was spread over it to completely cover the bone defect and titanium implant. After a few seconds, it was confirmed that a solid gel was formed. The exposed tissue is then sutured. Within 12 weeks after treatment, all jaw quadrants healed completely, with no wound healing failure or inflammatory response.

Table 4 beagle titanium implant experimental design

。

10.3 Imaging and observing:

at weeks 4 and 12 post-surgery, two-dimensional images of the mandible were monitored using a portable X-ray machine. For three-dimensional analysis, each specimen was scanned by micro-CT in cone-beam acquisition mode. The volume and mineral density of the new bone was measured using a CT analysis program. Three-dimensional surface rendered images were made using the Mimics14.0 version of imaging software.

After the teeth are missing, alveolar ridge bone resorption and reduction of alveolar bone height are expected to occur, which may reduce stability of the implant, reduce life of the implant, cause trouble of secondary planting to the patient, and even more, fail to perform secondary planting due to the reduction of alveolar bone height. The compound A hydrogel dressing prepared by the application is expected to prevent alveolar bone from decreasing, stimulate the vertical bone regeneration of the surrounding parts of the implant, and increase the bone mass so as to improve the stability of the implant.

After treatment of critical defect sites around implants with the hydrogel dressings of examples 3-5, changes in alveolar bone defects over time were monitored by intraoral X-ray. In the control group, slight bone resorption and implant exposure occurred at the peri-implant sites over time. In comparison with the control group, the hydrogel dressing group loaded with compound a prepared in examples 3 to 5 observed significant bone regeneration, the exposed screw threads of the implant were completely covered with new bone, and the degree of screw thread coverage with new bone increased with increasing content of compound a in the dressing.

10.4 Histological observation:

The effect of the hydrogel dressings of examples 3-5 on bone regeneration was evaluated by X-ray and microcomputerized tomography (CT) after 12 weeks of treatment.

For histological analysis, the mandible, including the implant, was removed using a high-speed water-cooled diamond saw and EXAKT cutting system.

The extent of bone regeneration was studied by X-ray and micro CT scanning. Bone tissue surrounding the four groups of implants was significantly different in height. In fact, the exposed areas of the control group were rarely covered by regenerated bone. However, examples 3-5 showed significant bone regeneration around the implant wall after hydrogel dressing treatment and increased with increasing content of compound a in the dressing. Examples 3-5 hydrogel dressing sets most of the area of implant screw thread was wrapped with vertically grown bone tissue. The hydrogel dressing sets of examples 3-5 had significantly increased bone volume compared to the control set. Examples 3-5 hydrogel dressings the bone volume in the region of interest (bone volume measured from the innermost point of the implant screw thread to 0.5 mm from the starting point) was 34.86mm3,35.74mm3 and 35.81mm3, in that order, with bone tissue completely covering the screw thread. Whereas the control bone volume was only 23.73mm3, implant screw threads were still observed. In summary, the bone regeneration effect of the hydrogel dressings of examples 3-5 was improved by 1.47-fold, 1.50-fold and 1.55-fold, respectively, compared to the control group. In addition, there was also a difference in bone mineral density (measured from the innermost point of the implant screw to 0.5 mm from the starting point) between the hydrogel dressings of examples 3-5 and the control. The specific experimental data are as follows:

TABLE 5 promotion of alveolar osteogenesis around titanium implants by hydrogel dressings of examples 3-5 and comparative examples

。

10.5 Tissue morphometric analysis:

All specimens were dehydrated through a series of gradient concentrations of alcohol. After dehydration, the specimens were embedded in acrylic resin. Longitudinal slice samples containing tissue and implants were obtained using a high speed water cooled diamond saw and EXAKT cutting system.

Histomorphometric analysis was performed using an optical microscope and Image-Pro Plus Image analysis system. The center section of each implant was used for histomorphometric analysis. The induced bone height (mm) was measured at 0.5mm, 1.0 mm and 2.0mm from the implant.

Histomorphometric analysis was performed to assess the extent of regenerated bone. Quantitative evaluation showed that bone tissue surrounding the implants of the four test groups had significant differences in vertical bone growth. Vertical bone augmentation was measured at each point 0.5mm,1.0mm,2.0mm from the implant wall. The control group had limited bone regeneration along the implant wall from the defect interface. However, the hydrogel dressing sets of examples 3-5 were significantly higher in bone height at all measurement points than the control set.

Examples 3-5 the vertical growth height of bone, measured from the hydrogel dressing set, was 0.33-0.44mm from the implant wall surface to 2.0mm from the implant. Examples 3-5 hydrogel dressing sets were much higher in bone height from each point than the control. The specific experimental data are shown in table 6.

TABLE 6 effects of example 3-5 and comparative hydrogel dressings on bone vertical growth height around titanium implants

。

The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.

Claims (7)

1. Use of a compound a for preparing a hydrogel dressing for promoting local bone tissue regeneration around a titanium implant, characterized in that the mass concentration of the compound a in the hydrogel dressing is 1.0% -2.0%, the chemical structure of the compound a is as follows:

。

2. Use according to claim 1, wherein compound a is used for the preparation of a hydrogel dressing for inhibiting bacterial growth around an implant.

3. The use according to claim 1, wherein the dressing is a hydrogel dressing.

4. The use according to claim 2, wherein the concentration of compound a in the dressing is 1.5% by mass.

5. The use according to claim 2, wherein the concentration of compound a in the dressing is 2% by mass.

6. Use according to any one of claims 3 to 5, wherein the dressing is a temperature sensitive hydrogel dressing.

7. Use according to claim 6, wherein the dressing is prepared by the following method:

step 1), dissolving a compound A in phosphate buffer solution;

Step 2) taking poloxamer 407, adding the poloxamer 407 into the solution obtained in the step 1), stirring while adding, and adding the poloxamer 407 into phosphate buffer solution after the poloxamer 407 is completely dissolved, and fixing the volume to the full volume;

and 3) taking the gel solution obtained in the step 2), sub-packaging the gel solution into penicillin bottles, adding rubber plugs, and rolling an aluminum cover to obtain the gel solution.