*3.7.1.3 Sticky bone with i-PRF*

This method has two main advantages:


To prepare sticky bone, already prepared i-PRF is mixed with a bone graft. Thanks to physiologic coagulation processes, the mixture becomes gelatinous after some time. To accelerate the coagulation process and to enhance density and firmness, adding 1–2 fibrin clots to the mixture can be considered (**Figure 5**).

*PRF and Sticky Bone as Regenerative Materials in Oral Surgery DOI: http://dx.doi.org/10.5772/intechopen.108807*

#### **Figure 5.**

*Making sticky bone. A) Adding i-PRF into the bone substitute. B) Gel starting to form. C) Gelling completed. D) Sticky bone.*

Sticky bone can be also prepared in a way that uses scissors to cut one or two PRF membranes into pieces. This is followed by adding a required amount of bone graft, thereby making a mixture. This should be thoroughly mixed all together with a PRF exudate. The PRF exudate is a liquid that is segregated upon PRF clot compression in the process of PRF membrane preparation. It contains autologous thrombin that stimulates coagulation as well as gelatinization. This gel-like mass can further be shaped in the desired shape. Every few seconds, i-PRF should be added to it drop by drop. In several minutes, the mass becomes gelatinous, and the sticky bone formed in this is ready for use.

#### **3.8 BIO-bone**

Bio-bone is a variant of sticky bone. It has improved characteristics and was patented by Richard Miron. Bio-bone is, in fact, a combination of Alb-gel, bone graft, and injectable PRF. In other words, in this autologous biomaterial, bone graft and ALB-PRF membrane with prolonged viability (4–6 months) are found together.

A Bio-PRF preparation protocol is identical to the ALB-PRF membrane preparation protocol. However, there is one distinction: after pouring one part of a liquid PRF (CGF) over a cooled ALB-gel, a layer of bone graft (preferably allograft)

should be added to it. Furthermore, the rest of the PRF (CGF) should be poured over this construction. It takes 15 minutes for this mass to become gelatinous and ready for use.

Thanks to the prolonged viability of the ALB-PRF membrane, sticky bone prepared in this way can be used in augmentative procedures without the usage of a collagenous membrane, consequently reducing the financial costs of the procedure.

### **4. PRF preparation equipment**

#### **4.1 Centrifuge**

The concept of PRF preparation is based on full blood centrifugation, which results in blood components' separation (for simpler understanding: red and yellow fractions). Relative centrifugation force (rcf) is the key in this process rather than rotations per minute (rpm) that represents a variable parameter dependable on centrifuge design and radius [41].

Nowadays, there are different protocols for PRF preparation that use centrifuges with different rotors, test tube angulation and design [42]. These protocols are based on the rpm values rather than rcf values. Although there are numerous articles addressing PRF, they cannot be adequately compared simply due to the heterogeneity in rcf reporting [41]. In other words, the very same protocol that utilizes different centrifuges provides us with different results. For this reason, it is highly important to use certified centrifuges such as the Intraspin device for L-PRF protocol (that has a fixed centrifuge angle of 33°), Duo Quatro centrifuge for A-PRF+ protocol (that has a fixed centrifuge angle of 40°), and Bio-PRF centrifuge for Bio-PRF protocol (that has horizontal centrifugation adjustment) (**Figure 6**) [42].

#### **4.2 Vacuum test tubes for platelet concentrate preparation procedures**

In the process of obtaining platelet concentrates, vacuum test tubes (also known as vacutainer tubes) are used. There are two types of test tubes: glass- and plastic-made test tubes (**Figure 7**).

The advantage of using glass test tubes lies in the glass' ability to stimulate coagulation [43]. Considering that a modern approach to PRF preparation entails the avoidance of additives and anticoagulants, empty glass test tubes are the ideal choice for PRF membrane and plug preparation. In case we opt for plastic test tubes, they should be equipped with a clot activator that accelerates the coagulation process. Such activators are micronized silica particles that coat the inside surface of vacutainers. If a test tube is coated with a clot activator, then its wall is blurred. Regardless of that, it has recently been reported that silica particles have side effect [44]. It is mostly related to a possible negative effect on tissue regeneration, cytotoxic effect, cell apoptosis, and PRF clot size [44–46]. Albeit no serious side effects have been reported up to date, it is recommended to use test tubes without any chemical additives [44–46].

Plastic vacuum test tubes without additives are made of polyethylene terephthalate (PET) plastic [47]. In contrast to glass and silica particle-coated plastic test tubes with a red cap that are hydrophile, these plastic test tubes are hydrophobic. In these test tubes, the yellow fraction (liquid PRF) remains in a liquid state for 30 minutes under the hermetic conditions upon centrifugation. In conclusion, these test tubes are used

*PRF and Sticky Bone as Regenerative Materials in Oral Surgery DOI: http://dx.doi.org/10.5772/intechopen.108807*

**Figure 6.** *Fixed angle and horizontal centrifuge.*

#### **Figure 7.**

*Blood collection tubes. (A) 10 ml glass vacuum red cap tubes for PRF membranes. (B) 10 ml silica-coated plastic tube with no additive for PRF membranes. (C) 13 ml, 10 ml, and 9 ml PET tubes with no additive added for sticky bone, large PRF membranes, and facial esthetics.*

in liquid PRF, CGF, and sticky bone preparation. Liquid PRF nowadays is frequently used in facial esthetic procedures.

A correct test tube selection is of vital importance for obtaining safe and highquality PRF products. Oftentimes this may be an issue considering that there are test tubes of low and ambiguous quality in the market. For this reason, clinicians are recommended to use test tubes from safe and trustworthy retailers.
