Dentoria

Abstract

Following new trends in medicine, the application of growth factors in regenerative dentistry plays a key role in the osteointegrative process, which is multifactorial, so the use of autologous materials significantly affects the acceleration and success of the final therapy. Modern implantology, on the other hand, allows for a successful level of osseointegration of the implanted dental implant, so that an aesthetic and functional result can be further achieved in the patient. The benefit of local-topical application of platelet concentrate obtained from autologous plasma is widely used in dentistry, as a separate branch for bioactivation of dental implants in the bone-tissue segment, prepared for immediate or delayed loading with a superstructure.

Objective: The primary and main objective of this study is to determine the relationship between the level of early osseointegration and secondary stability in dental implants using autologous platelet concentrate during dental implant placement in all 3 phases, at the time of dental implant placement, after 4 weeks, and after 8 weeks of placement.

Material and Method;

A study was conducted on 32 subjects of both sexes aged 20-64 years. In all subjects with an indication for dental implant placement, venous blood was extracted via venipuncture through a patented 8ml vacuum tube with citrate as an anticoagulant. The tubes were centrifuged at 4000 rpm for 6 minutes, the time required to obtain a plasma concentrate.

In each patient, during the preoperative planning phase, an analysis of two-dimensional and three-dimensional panoramic X-ray images of an intraoperative clinical macroscopic examination was performed, at the intended sites for placement of dental implants in the lower jaw (with total edentulism) using the standardized classification system for the gradation of mandibular bone atrophy according to Lekholm and Zarb.

After the oral surgical procedure, the stability of the placed dental implants was measured using the PenguinRF device on the day of the intervention, 4 weeks after the placement of the dental implant and sulcus formation, and 8 weeks after the placement of the dental implant. The subjective feeling of pain was measured according to a graduated five-point VAS pain scale, using the T-test we analyzed the differences between the PRP and control groups in all four intervals. The differences were tested using the ANOVA test used for repeated measurements (Repeated Measures ANOVA). Additional tests were performed using the Bonferroni Post Hoc Test. Initially, the differences were tested for the entire sample, and then analyses were performed in relation to the PRP group and the control group, each separately. Using the Pearson correlation coefficient, the stability of dental implants and their correlation with the age group of patients were analyzed. The statistical significance of this test is a threshold value of p=0.05. The results obtained showed us that stability is not correlated with the age of the subjects. Using the ANOVA test, we analyzed the relationship of the subjects with D1 and D2 bone tissue in terms of stability of dental implants. Subjects with D3 and D4 are not included in this analysis, due to an insignificant number of subjects in the group itself. It is summarized that subjects with D1 and D2 bone density do not differ statistically significantly in terms of stability of dental implants.

Results In the group of subjects (32) where autologous platelet-rich plasma was used, the primary measurements indicated higher measurements in terms of the stability of the dental implants, as follows: postoperatively 79.59; after 4 weeks with an average value of 80.46 and after 8 weeks (a period that we consider to be the achievement of the level of osseointegration) the average value using the Penguin multi-system is numbered as 84, which does not indicate satisfactory stability and the possibility of timely loading of the dental implant.

Conclusion: According to our results, dental implants placed with platelet concentrate showed a statistically significant difference in stability measured using Penguin-resonant frequency analysis at all three time periods: postoperatively, after 4 weeks and 8 weeks.

Introduction

Modern methods and treatments for using bioactive materials to achieve osseointegration of dental implants may affect osteoblast adhesion to the implant surface. Although it can be said that the technique of placing dental implants has not significantly changed, a sufficient number of studies are investigating the possibility of using and applying platelet concentrate (PRP) derived from plasma, which may affect the improvement of stability and the osseointegration process in placed dental implants.

PRP is actually an “extract” from blood containing various growth factors, which, after centrifugation, is obtained as a final product for clinical application. Thrombin is a substitute for serine protease, which in humans is encoded by the “F2” gene and converts soluble fibrinogen into insoluble fibrin.1 Today, implant therapy is considered a predictive treatment with excellent and long-term results, knowing that the osseointegration process is multifactorial, the use of autologous materials can help accelerate and succeed the therapy, PRP as a method has long been a proven tool for successful therapy in dentistry.

The stability of a dental implant is defined as the ability or condition to absorb appropriate forces coming from multiple directions, from an axial aspect, lateral or rotational movements. Wound healing and bone regeneration require a series of orchestrated sequences of biological factors that can be of crucial importance for the long-term stability of dental implants, for their primary and secondary stability. Perhaps one of the most “candidates” to ensure all of the above is platelet-rich plasma. This can be explained by the fact that: 1) it is of autologous origin; without the risk of disease transmission, and 2) it contains natural growth factors that can influence bone regeneration. 2,3,4

The purpose of this paper is actually to provide a basis for evaluating and influencing the effect of platelet-rich plasma and its seven fundamental protein growth factors in improving dental implant stability in relation to the topographic characteristics of the implant surface.

Material and Method;

Inclusion criteria for this study are:

patients aged 18-64 years.
patients with bone resorption <6 mm in the lower jaw
patients with one or more missing teeth in the posterior/distal region
patients with adequate interocclusal distance and mesio-distal space sufficient for dental implantation
absence of acute or chronic inflammatory symptoms that may affect the success of osseointegration of the dental implant
indication for extraction of carious destroyed teeth for the purpose of replacing dental implants
indication for performing multiple extractions for the purpose of planning and placing dental implants
partial or total edentulism of the lower jaw
patients who signed a written document for the surgical intervention, as well as consent for the placement of dental implants.

In the first group (experimental), dental implants were placed in the lower jaw - right side, with previously prepared and locally applied autologous 'protein-rich plasma with appropriate concentration - PRP' to the implant site, while in the second group (control), in the same patient on the left side of the mandible, only a standard protocol for implant site preparation was used, but without the application of concentrated autologous plasma prepared in a plasmalifting tube with heparin that has a patented separation gel, which through platelet degranulation releases appropriate growth factors and other cytokines that stimulate the growth of bone and soft tissues.

According to the inclusion criteria in the study, patients aged 18-64 years with appropriate inclusion criteria were selected in this double-blind randomized clinical trial. A survey questionnaire was administered to all respondents along with consent for voluntary participation in our study, following the WHO recommendations. With a set indication for implantation of dental implants in the lower jaw, depending on the loss and remodeled bone surface. In the first group (experimental) in the lower jaw-right side, autologous “protein-rich plasma PRP” was previously prepared and locally applied. Concentrated autologous plasma prepared in a plasma lifting tube with citrate as an anticoagulant, which has a patented separation gel, was applied to the implant site, which, through platelet degranulation, releases appropriate growth factors and other cytokines that stimulate the growth of bone and soft tissues, while in the second group (control), in the same patient on the left side of the mandible, only a standard protocol for preparing the implant site was used. To obtain the final product, all aseptic prerequisites for obtaining 8 ml of liquid blood from an antecubital vein were observed. Autologous platelet concentrate was used for each patient. After obtaining the blood, it was transferred to a sterile vacutainer containing 0.5 ml of 3.2% sodium citrate, the action of which is based on the principle of anticoagulantity.

The tubes are centrifuged at 4000 rpm for 6 minutes, after which the necessary plasma is obtained in the upper-superior part of the tube. In the lower part, the erythrocytes, leukocytes and the separation gel are denatured. The obtained plasma was injected before the placement of the implants into the formed place-bed for the implant, on the surface of the implant, as well as after the placement of the implant.

After completion of the oral surgical procedure, the stability of the placed dental implants was measured using a device (Penguin RFA) on the day of the intervention, on the 4th week after placement, and on the 8th week after placement of the implant.

Results

The average age of the patients ranged from Min=31 to Max=77 years. The average age of the total number of patients (sample) was M=54.91±10.45 years. The age of the PRP group was M=54.50±10.45 years, and the control group had a mean value of M=55.39±10.63. These samples of respondents were leveled according to the average value of years (F=0.107, p=0.745).

Female patients are represented by 34.3% (N=11). A total of 65.7% (N=21) are male respondents. If we consider only the observation of dental implants as a statistical unit, then the groups are equivalently equal in terms of gender (χ²=0.033, df=1, p=0.855). The group of respondents with PRP is represented by 56.6% of males and 34.4% of females, and in the control group, males dominate with 67.9% compared to females 32.1%.

Table 1. Dental implant stability – difference between PRP and control group

	Group	N	M	SD	t	df	p
Dental Implant Stability_Postoperative	PRP Group	32	79.59	2.72	3.166	58	*0.002*
Dental Implant Stability_Postoperative	Control Group	28	77.50	2.34	3.166	58	*0.002*
Dental Implant Stability_After 4 Weeks	PRP Group	32	80.46	2.44	3.063	58	*0.003*
Dental Implant Stability_After 4 Weeks	Control Group	28	78.53	2.42	3.063	58	*0.003*
Dental Implant Stability_After 8 Weeks	PRP Group	32	84.00	2.09	2.970	58	*0.004*
Dental Implant Stability_After 8 Weeks	Control Group	28	82.50	1.77	2.970	58	*0.004*

N=number of respondents, M=arithmetic mean, SD=standard deviation, t – t test, df- degree of freedom, p=statistical significance;

Discussion

The stability of dental implants is one of the most important parameters that influence and are an indicator of early loading of the implant, and at the same time affect the success of the osseointegration process with the bone structure and geographical surface of the implant itself. Most studies that have examined the stability of dental implants based on the so-called ISQ - stability quotient, indicate that an implant with a value of ISQ <49 obtained postoperatively should not undergo the next step, which is prosthetic loading, which is actually inversely proportional to values with ISQ >54.

The process of healing and enabling bone regeneration is a kind of orchestra of biological sequences regulated by multiple factors that influence bone healing which is crucial to ensure adequate stability of the implant bed. In order to promote and encourage early osseointegration with qualitative bone formation, companies, and most researchers 5,3,6,7 have proposed several types of modifications of the dental implant which on the other hand will ensure maximum bone-implant contact for the entire period, up to the moment of prosthetic loading. The dental implant provides its first contact in the human organism-recipient (i.e. oral cavity) through the blood. One of the novelties in oral implantology that have been used in recent history is actually the application of autologous platelet concentrate (PRP) on the surface of the dental implant itself, immediately before applying it to the implant bed. In our work, the difference postoperatively between the examined group versus the control group is statistically significant for p=0.002, which indicates a mild stability even at the beginning of the placement of the implants. Thus, according to the first innovator Kingsley 1 of this autologous concentrate, α-granules release growth factors in the first 3-5 days of platelet activation and their stimulation is reflected in the proliferative phase after 10 days of application. In fact, these growth factors activate, i.e. accelerate the healing process only when their level is functional with a reached level of platelet concentrate, which in turn will affect the synthesis of collagen and α-granules through the initial formation of callus in bone tissue. Platelets persist for 7-10 days and are in collision with other platelets, forming a stable fibrin network with a stable plug/thrombus. Dr. Marks 8, in 1998, first used the application of PRP as a basis that supports the reconstructive graft on a bone substrate, and hence a series of studies to prove and apply the postulate followed. Analyzing the experimental studies related to the application of plasma concentrate, most authors emphasize the positive effect in improving bone quality and stability, allowing significantly improved bone regeneration compared to the isolated application of autologous bone graft 9.

The local application of platelet concentrate during dental implant placement is a relatively simple and simplified method that can contribute to ensuring early implant-bone contact. According to a group of authors 10,11,12,13, in their studies whose aim was to see the immediate loading of dental implants in distal segments of the lower jaw, where the probability of the maximum masticatory effect is precisely in those anatomical regions, they suggest that the bioactive potential of platelet concentrate can be influenced directly or indirectly through several selected factors, some of which are: careful selection of the implant site, computer analysis of bone quality and quantity in order to ensure the appropriate length of the implant, ensuring satisfactory primary stability of the placed implants and exclusion of high-risk patients with compromised health, which can affect primary and secondary stability. It follows that our results in this study for loading after 8 weeks show a statistical significance of p=0.004, which is in correlation with some of the conclusions obtained in the study by the above-mentioned group of authors.

The results obtained in our paper are in correlation with some of the conclusions obtained in the study of a group of authors 14,15 where dental implants placed with platelet concentrate showed a statistically significant difference in stability measured using Penguin-resonant frequency analysis in all three time periods: postoperatively (p<0.01), after 4 (p<0.01) and 8 weeks (p<0.01).

Conclusion

According to our results, dental implants placed with platelet concentrate showed a statistically significant difference in stability measured using Penguin-resonant frequency analysis in all three time periods: postoperatively (p<0.01), after 4 (p<0.01) and 8 weeks (p<0.01), which does not indicate satisfactory stability and the possibility of timely loading of the dental implant. The results showed that the stability of dental implants is statistically significant with higher values in relation to primary and secondary stability and after 8 weeks of their placement. Statistically significant differences were observed in the entire sample of respondents, but in the PRP group of patients the satisfactory osseointegration process, which is multifactorial, contributed to the use of autologous materials as the PRP method helping to accelerate and succeed the therapy.

Reference