Suture materials and biomaterials

Chapter

7 

Suture materials and biomaterials Anson J. Tsugawa & Frank J.M. Verstraete

GENERAL PRINCIPLES Sutures placed intraorally are exposed to tissues of high vascularity, a constant bathing of saliva, bacteria, fluctuations in temperature and pH and masticatory trauma.1 The tissue reaction to the placement of sutures in the mouth is different from that seen in other regions of the body.2 Peak tissue reactions have been reported to occur between the second and seventh days for tissues other than the oral cavity.3 The physical character of the suture material is the most important consideration in determining intraoral tissue reactivity; in general, monofilament and nonabsorbable sutures are less reactive than multifilament and absorbable suture materials.2,3 The capillarity of a suture material, the process by which fluid and bacteria are trapped in the interstices of multifilament materials, is also an important consideration for the intraoral placement of sutures, as multifilament sutures are more likely to contribute to the wicking of bacteria and oral fluids deep into the wound.2,4 Suture materials intended for intraoral use should accumulate little or no bacterial plaque.1 Furthermore, absorbable suture materials are favored over nonabsorbable materials because they enhance patient comfort and eliminate the need for removal. The additional manipulations required during intraoral suture removal may predispose to bacteremia and endocarditis in the high-risk cardiac patient.5 The primary objective of dental suturing is to achieve apposition of wound edges to promote optimal healing.6 Blood and serum that accumulate beneath the inappropriately apposed flap delay the healing process.6 Sutures function to appose wound edges until the supported tissues have regained sufficient strength to withstand tensile forces. When their strength is no longer needed, the suture material should absorb completely and predictably to prevent additional delays in healing.1 The ideal time for suture loss specific to the oral tissues has not been clearly defined.1 It has been suggested, however, that 4 days is the optimum time for suture removal; by 72 hours, a stratified squamous keratinized epithelial layer has formed in the attached gingiva.7,8 Connective tissue healing with type III and type I collagen occurs by 96 hours.9,10 When selecting a suture material, the surgeon should consider the physical properties of the suture material (capillarity, size, tensile strength, absorbability surface characteristics and tissue reactivity) and © 2012 Elsevier Ltd DOI: 10.1016/B978-0-7020-4618-6.00007-5

the rate of wound healing in the area.3 All too often, however, the selection of suture material by the surgeon is based on handling properties alone. The minimal requirements for an intraoral suture material are outlined in Table 7.1.

SUTURE CHARACTERISTICS Suture materials may be absorbable or nonabsorbable, and monofilament or multifilament (see Table 7.1). Absorbable suture materials have been defined by the United States Pharmacopeia (USP) as strands of collagen or synthetic polymers that are capable of absorption in mammalian tissue. In contrast, nonabsorbable sutures are strands of material that are resistant to absorption. Monofilament suture materials are composed of a single strand of material, and multifilament sutures are braided or woven from multiple strands of material.

Physical properties Handling characteristics The handling characteristics of a suture material are intimately associated with the intrinsic stiffness of the material. Suture materials that are more pliable and of smaller diameter have favorable handling characteristics to stiff suture materials of large diameter.11 When cut, the sharp ends of stiff suture materials (e.g., stainless steel or nylon) can result in the mechanical irritation of tissues. As a general rule, multifilament sutures have better handling characteristics than monofilament sutures, as well as uncoated sutures compared to coated ones. Related to stiffness is elasticity. Most suture materials exhibit limited elongation when exposed to increasing loads. Notable exceptions are polypropylene and polybutester, which are relatively elastic. The surface of uncoated braided materials such as polyglycolic acid is rough and causes considerable friction and trauma when going through tissues.

Capillarity The degree of bacterial transport along suture filaments is determined by the fluid absorption and capillarity of the suture material.12 Monofilament sutures withstand contamination better than multifilament

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Table 7.1  Minimal physical and biological requirements for intraoral suture materials 1. Fast absorption with minimal tissue reactivity 2. Good short-term tensile/knot strength with sutures of small diameter 3. Minimally plaque retentive 4. Low capillarity and fluid absorption 5. Knots with good security and without injury to the soft tissues 6. Low tissue drag 7. High pliability for favorable handling in confined areas

sutures, and tissue reactivity is minimized with monofilament suture materials.13 Multifilament sutures have a five- to eightfold higher affinity for bacterial adherence than monofilament nylon sutures.14

Tensile strength, knot-pull tensile strength and knot security The tensile strength of a suture material refers to the strength required to break an untied portion of suture when a force is applied along its length (Table 7.2).15 Thicker-diameter sutures have greater strength than smaller-diameter sutures, but the thickness also increases the total amount of foreign material in the wound and the severity of associated tissue reaction.16 The knot is mechanically the weakest link of the suture loop, tension forces are converted into shearing forces at the knot, and the initial tensile strength of a suture is reduced by at least one third.17,18 Knot-pull tensile strength is defined as the force in pounds that is required to break a knotted strand of suture material, whereas knot security refers to the knot holding capacity of a suture material expressed as a percentage of the tensile strength. The knot-pull tensile strength is related to the diameter of the suture, the type of suture material and the size of the suture loop.18,19 Knot security is influenced by the suture diameter, coefficient of friction and the quality of the knot.18–20 When induced to failure, secure knots break rather than untie due to slippage of the knot.21 In general, the use of larger-diameter sutures and the placement of additional throws in the knot will increase the security and reliability of the knot.16 More specifically, catgut, poly­ glycolic acid, polyglactin 910 and polypropylene require three throws to ensure knot security; four throws are necessary for polydioxanone and polyamide.21

Biologic properties Suture materials may be derived from natural or synthetic sources. Synthetic sutures account for almost all of the currently used suture materials, and the only naturally derived examples discussed here include catgut and silk (see Table 7.2). Natural and synthetic sutures differ in their mechanism of absorption. Natural sutures are degraded and absorbed by the proteolytic enzymes supplied by macrophages, and synthetic sutures are degraded by hydrolysis in tissue fluid.

Biofilm Biofilms are complex communities of surface-associated cells enclosed in a polymer matrix containing open water channels that can develop on many different medical devices, including suture materials.22 Biofilms serve as a reservoir for bacteria. Bacteria growing on the surface of a biofilm have been shown to display a unique phenotype with increased resistance.23 Within biofilms, bacteria are hidden from the

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host immune system and are less susceptible to antibiotics.22 Complete elimination of bacteria from biofilms on suture material may be impossible.22 The bacteremia created by suture removal and the potential risk of endocarditis has led to the suggestion of antibiotic prophylaxis at the time of suture removal in compromised patients but this is controversial.24

Tissue reactivity All suture materials elicit a foreign body cellular reaction when they are implanted into tissues, but natural sutures exhibit greater tissue reactivity than their synthetic counterparts, and the inflammatory phase of wound healing is prolonged (see Table 7.2). The most inert materials are monofilament synthetics such as nylon and steel. The more material that is implanted in a wound, the greater the tissue reaction, and the knotted portion of the suture loop contains the highest density of foreign material.25 Suture size contributes more to tissue reaction than extra throws to the knot.16

Influence of wound infection The placement of foreign material in an infected wound can exacerbate or perpetuate infection; therefore, whenever possible, the surgeon should avoid placing sutures in heavily contaminated wounds that require immediate closure.26 Sutures may potentiate infection by inducing an exudative foreign body response with local tissue auto­ lysis and by physically shielding the bacteria from the host defense.26 For this reason, multifilament sutures are not recommended for use in contaminated wounds, as the clearance of bacteria from the interstices of multifilament materials is slower than with monofilament materials.26 Although the physical and chemical structure of a suture material influences the degree of infection, proper surgical technique and wound care also play important roles in minimizing wound infection.26

Influence of pH The pH level in tissues and body fluid varies by location (e.g., gastric juice, 0.9 to 1.5; and pancreatic juice in the duodenum, 7.5 to 8.2), and is influenced by the presence of infection and inflammation. Proteus, a urea-splitting bacterium, dissociates urea to ammonia and elevates the pH of urine. The pH of inflamed tissue is generally acidic.27 The pH of a tissue can affect the retention of tensile strength of suture materials. The degradation of natural absorbable sutures is accelerated in both acidic and alkaline pH but, in general, only alkaline conditions have a significant effect on synthetic absorbable sutures.27 Polydioxanone is a notable exception, as it degrades faster in acidic solutions.28 Silk is the most vulnerable of nonabsorbable sutures to fluctuations in pH, but nylon also exhibits a degradation in tensile strength in acidic environments.27,28 Polypropylene, a synthetic nonabsorbable suture material, retains its initial tensile strength over a wide range of pH.28

SUTURE MATERIALS Catgut Plain catgut is a natural suture material derived from the submucosa of sheep intestine or the serosa of cattle intestine. Chromic catgut is a modification of plain catgut that is tanned with chromic salts to improve strength and delay dissolution.29 Gut is absorbed by phagocytosis, and is associated with a marked tissue inflammation that can

Absorbable Multifilament Absorbable Multifilament Absorbable Multifilament

Surgical guta Chromic gutb

Dexon Sb (uncoated) Dexon IIb (coated)

Vicryla

Catgut (chromic)

Polyglycolic acid

Polyglactin 910

Absorbable Monofilament Absorbable Monofilament Nonabsorbable Monofilament/ multifilament

Nonabsorbable Monofilament Nonabsorbable Monofilament Nonabsorbable Monofilament Nonabsorbable Multifilament

Nonabsorbable Monofilament/ multifilament

Nonabsorbable Multifilament

Maxonb

Monocryla Monocryl Plusa

Ethilona (monofilament) Nurolona (multifilament) Dermalonb (monofilament) Surgilonb (multifilament)

Novafilb

Prolenea Surgiprob Surgipro IIb

Pronovaa

Mersilenea (uncoated) Ethibond Excela (coated) Ti-cronb Surgidacb

Surgical Stainless Steela (monofilament) Surgical Stainless Steela (multifilament) Steelb (monofilament) Flexonb (multifilament)

Perma-Handa Sofsilkb

Polytrimethylene carbonate

Poliglecaprone 25

Polyamide

Polybutester

Polypropylene

HexafluoropropyleneVDF

Polyester

Stainless steel

Silk

Proteolytic enzymes and phagocytosis

N/A

N/A

N/A

N/A

N/A

Hydrolysis (slow)

Hydrolysis

Hydrolysis

Hydrolysis

Hydrolysis

Hydrolysis (phagocytosis)

Hydrolysis

Hydrolysis

Proteolytic enzymes and phagocytosis

Degradation

Severe

Minimal acute

Minimal acute

Minimal acute

Minimal acute

Minimal acute

Minimal acute

Minimal acute

Minimal

Slight

Minimal acute

Minimal acute

Moderate

Tissue reactivity

70% after 14 d; 50% after 30 d

N/A

N/A

N/A

N/A

N/A

15–20% loss after 365 d, retains remaining 80% indefinitely

50–60% after 7 d; 20–30% after 14 d; 0% within 21 d

81% after 14 d; 59% after 28 d; 30% after 42 d

74% after 14 d; 58% after 28 d; 41% after 42 d

>28 48

75% after 14 d

50% after 5 d; 0% at 14 d

75% after 14 d

65% (55% sizes 7–0 or smaller) after 14 d; 35% (20% sizes 7–0 or smaller) after 21 d

Unpredictable

Tensile strength retention (%)

2830

31

2830

7–1448; 16–2035

3–748; 7–1035 (variable, shorter in infected wounds)

Intraoral survival time (days)*

Gradual encapsulation by fibrous tissue

N/A

Gradual encapsulation by fibrous tissue

N/A

N/A

N/A

Gradual encapsulation by fibrous tissue

91–119

180

180

56–70

42

56–70

60–90

45–60

Complete absorption (days)

Chapter

*Spontaneous loss a Ethicon, Inc., Somerville, NJ b U.S. Surgical, Norwalk, CT

Absorbable Monofilament

PDS II PDS Plusa

Polydioxanone

a

Coated Vicryl Plusa

Vicryl Rapidea

Type

Trade name

Suture

Table 7.2  General characteristics of suture materials used in veterinary oral and maxillofacial surgery

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be detrimental to healing. Conversely, tissue inflammation may lead to a more rapid breakdown of catgut. Plain gut has a median survival time of 4 days in the oral cavity, whereas chromic gut retains its strength for 2 to 3 weeks.26,30 In moist environments such as the oral cavity, the strength of gut is reduced by 20–30%.31 Gut is a stiff material that must be moistened in alcohol, and forms knots that can be irritating to the oral tissues.32,33 Infection rates may increase with the use of gut.34 The advent of synthetic materials preferable to gut, with less tissue reactivity and more predictable resorption, has almost made catgut obsolete.25

Synthetic absorbable suture materials Polyglycolic acid Polyglycolic acid is a multifilament suture material derived from a homopolymer of glycolic acid (hydroxyacetic acid), and is available uncoated (Dexon S, U.S. Surgical, Norwalk, CT) or coated (Dexon II, U.S. Surgical, Norwalk, CT) with polycaprolate, a copolymer of glycolide and ε-caprolactone. Polyglycolic acid is absorbed by hydrolysis with less associated tissue inflammation than silk, plain or chromic catgut.35 The median survival time of polyglycolic acid in the oral mucosa is 15 days (16 to 20).30,35 The initial tensile strength of polyglycolic acid exceeds that of silk and gut, but is decreased appreciably when placed in oral tissue.36 The handling characteristics of polyglycolic acid are favorable, similar to silk, but its knot security is poor.37 Polyglycolic acid also has a tendency to cut through friable tissue, which is not a favorable quality for suturing gingival tissues.21 Poly­ glycolic acid has been shown to inhibit bacterial transmission due to the release of monomers.37

Polyglactin 910 Polyglactin 910 is a braided suture material that is a copolymer of glycolic and lactic acid. The lactic acid provides water repellence, delaying the loss of tensile strength. Vicryl (Vicryl, Ethicon, Inc., Somerville, NJ) is coated with polyglactin 370 and calcium stearate to decrease tissue drag and bacterial adherence. It is absorbed by hydrolysis, and its intraoral survival rate is approximately 28 days.30 Complete resorption may take up to 40 to 60 days.38 Because polyglactin 910 persists much longer than is necessary for intraoral wound healing, it is not an ideal suture material for periodontal procedures.38 The long absorption time of polyglactin 910 also makes it a potential nidus for infection. Vicryl Rapide (Vicryl Rapide, Ethicon, Inc., Somerville, NJ) is an irradiated form of polyglactin 910 that is lost from the skin as early as 10 to 14 days. Intraorally, the median time for suture loss of Vicryl Rapide is 3 days.1 Gamma radiation alters the molecular structure of polyglactin 910 and enhances its in vivo absorption rate.39 In contrast to nonirradiated polyglactin, Vicryl Rapide may also be absorbed by phagocytosis.39 Vicryl Rapide remains in the skin longer than 5 days and is not recommended for facial skin closure.40 Irradiated polyglactin 910, however, satisfies many of the minimal physical and biological requirements for an intraoral suture outlined in Table 7.1; these include fast absorption, ease of handling, good knot security and minimal inflammatory reaction of the surrounding tissues.41 Although Vicryl Rapide is favorable in terms of its enhanced absorption rate, it has a tendency to be more brittle than nonirradiated polyglactin 910, and break if tugged on suddenly.41 Coated Vicryl Plus (Coated Vicryl Plus, Ethicon, Inc., Somerville, NJ) is a recent addition to the Vicryl suture material family that contains the synthetic broad-spectrum antimicrobial agent triclosan (2,2,4′-trichloro-2′-hydroxy-diphenyl ether).42 Triclosan is an anti­ microbial agent found in many personal/oral healthcare products,

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and is a potent inhibitor of enoyl acyl carrier protein (ACP) reductase, an essential enzyme in bacterial fatty acid biosynthesis.43 In general, triclosan is considered more effective against Gram-positive than Gram-negative species.43 Coated Vicryl Plus exhibits the same physical and functional handling properties as Coated Vicryl and the only difference between the two products is the addition of 100–500 ppm of triclosan to the coating.44 The addition of triclosan to Coated Vicryl was found to affect neither wound healing nor its absorption pattern.42 Coated Vicryl Plus exhibits in vitro antimicrobial activity against Staphylococcus aureus and S. epidermidis, the most prevalent organisms associated with surgical wound infection, for up to 7 days in an aqueous environment.45 Triclosan has shown sustained antimicrobial activity during the period of wound reepithelialization within the early postoperative period.46 The antimicrobial efficacy of triclosancoated suture material was unhindered when coated with biologic substrates, 20% bovine serum albumin, that mimics the tissue proteins recruited to the margins of a surgical wound.46 Besides the obvious bactericidal benefit of antibacterial-coated sutures, coated sutures have also demonstrated an ability to significantly reduce bacterial adherence compared to noncoated suture material.46 The usefulness of Coated Vicryl Plus in the oral cavity is related to triclosan’s ability to control oral plaque, and is supported by studies showing the effectiveness of triclosan in oral rinses and dentrifices.43 Incorporation of antibacterial agents such as triclosan into suture materials, however, is not without controversy; species such as Pseudomonas aeruginosa have already been found to be resistant to various antiseptic agents, including triclosan.46

Polydioxanone PDS (PDS II, Ethicon, Inc., Somerville, NJ) is a polyester of the monomer paradioxanone. PDS is hydrolyzed much slower than other absorbable suture materials, and retains 74% of its original tensile strength at 2 weeks, 58% at 4 weeks and 41% at 6 weeks.47 In a comparison study of suture materials in the feline oral cavity, PDS was found to be intact at day 28.48 When used on the gingiva, the hard ends of the suture material may be abrasive to the buccal mucosa that comes into contact with them. PDS is useful in wounds where a long healing time and extended tensile strength are required.47,48 Although PDS was developed for use as a resorbable suture material, it has also successfully been used as a resorbable alternative to stainless steel wire in transosseous fixation.49 Similar to Vicryl Plus, an antibacterial version of PDS, PDS Plus (PDS Plus, Ethicon, Inc., Somerville, NJ), has recently been introduced. PDS Plus inhibits bacterial colonization of the suture by S. aureus, S. epidermidis, Escherichia coli and Klebsiella pneumoniae.

Polytrimethylene carbonate Maxon (Maxon, U.S. Surgical, Norwalk, CT) is derived from a copolymer of glycolide and trimethylene carbonate. Maxon is very similar to PDS in terms of tensile strength and long tissue retention but is less rigid.26 Because of its long retention time, Maxon is less desirable as a suture material for routine intraoral use. Maxon retains 81% of its original tensile strength at 2 weeks, 59% at 28 days and 30% at 42 days.47 Resorption occurs by hydrolysis between 180 and 210 days.50

Poliglecaprone 25 Monocryl (Monocryl, Ethicon, Inc., Somerville, NJ) is an extremely pliable monofilament suture material that is derived from a segmented copolymer of ε-caprolactone and glycolide.51 The pliability of Monocryl contributes to its excellent handling characteristics.52 Monocryl loses 20–30% of its original tensile strength after 2 weeks,

Suture materials and biomaterials and is completely absorbed by hydrolysis in 90 days.51 Similar to other absorbable sutures that resorb via hydrolysis, Monocryl exhibits minimal tissue reaction that is characterized by macrophages, fibroblasts, lymphocytes, plasma cells and giant cells.51,52 Monocryl has superior tensile strength and is less reactive than polyglactin 910.52 In a recent study involving human patients undergoing dentoalveolar surgery, microbial adherence to Monocryl was shown to be significantly lower than nonresorbable multifilament and monofilament sutures.53 A triclosan-coated version of Monocryl, Monocryl Plus (Monocryl Plus, Ethicon, Inc., Somerville, NJ), is also available.

Synthetic monofilament nonabsorbable suture materials Polyamide Nylon (Ethilon, Ethicon, Inc., Somerville, NJ) is a synthetic polyamide polymer fiber that is a popular suture for cutaneous closure. Nylon is classified as a nonabsorbable suture, but does exhibit some absorption by hydrolysis and loses 15–20% of its tensile strength per year.26,29 The hydrolysis of nylon is influenced by the acidity of the milieu, as acids catalyze the hydrolysis of the amide linkages in nylon.29 The tissue reactivity of nylon is minimal, but its knot security is poor, and multiple throws are required to properly seat a suture. If used as an intraoral suture material, the sharp cut ends of nylon can be irritating to the patient and injurious to the oral soft tissues.42 Soaking in alcohol may improve pliability.26

Polybutester Novafil (Novafil, U.S. Surgical, Norwalk, CT) is a copolymer composed of polyglycol and polybutylene terephthalate. Compared to nylon, Novafil is less stiff and has a lower memory. Novafil also has greater elasticity then either nylon or polypropylene, and the unique feature of being able to stretch 50% of its length under low loads; as a result, Novafil is able to passively accommodate wound edema, reducing suture marks and cut-throughs.26,54 Although synthetic nonabsorbable sutures are rarely used intraorally, Novafil can be used safely in the mouth with less patient discomfort than nylon.55

Polypropylene Prolene (Prolene, Ethicon, Inc., Somerville, NJ) is a synthetic nonabsorbable monofilament that is derived from the polymerization of propylene. The absorption of Prolene is virtually nonexistent. Its tissue reactivity is low, and is preferable for treating contaminated sites. In comparison to nylon, Prolene has better knot security, elasticity, and pulls smoothly through tissues. The plasticity of Prolene sutures accommodates tissue swelling and reduces trauma to the sutured tissue.26

Hexafluoropropylene-VDF Pronova (Pronova, Ethicon, Inc., Somerville, NJ) is a new synthetic nonabsorbable monofilament that is uniquely composed of two polymers: polyvinylidine fluoride homopolymer and polyvinylidine fluoride hexafluoropropylene copolymer. Pronova is comparable to polypropylene in terms of biocompatibility, and its advantages are reduced package memory, easier handling, greater tensile and knot strength, and greater resistance to instrument damage. Pronova has been marketed for use in cardiovascular, ophthalmic and neuro­ surgery, but can also be used for general soft tissue wound closure and ligation.

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Synthetic multifilament nonabsorbable suture materials Polyester Polyester is a braided suture material that is available uncoated (Mersilene, Ethicon, Inc., Somerville, NJ) or coated (Ethibond Excel, Ethicon, Inc., Somerville, NJ) with polytetrafluoroethane. The coating minimizes capillarity and allows for tissue passage with less friction, but the coating may crack off after knots are tied, resulting in deposition of foreign material in the wound.3 Because polyester is braided, its handling characteristics are better than monofilament nylon but, as a result, it is predisposed to greater bacterial adherence. Polyester has low tissue reactivity, and is retained within the wound in a fibrous cartilaginous capsule.56 Due to its high tensile strength and knot security, polyester is an excellent suture for mobile facial areas, tracheal anastomosis and respiratory tract surgery.26,56

Stainless steel Stainless steel sutures are composed of low-carbon, iron-alloy strands, and are available as either a monofilament or a multifilament.30 Stainless steel has low tissue reactivity, and good tensile strength and knot security. Monofilament stainless steel is difficult to handle, and is used infrequently as a suture material in periodontal surgery, but is occasionally used around the lips to prevent suture removal in dog and cat patients.39 Its characteristics are very similar to monofilament synthetic nonabsorbable suture materials, and it is used more commonly for the internal fixation of fractures. Multifilament stainless steel is easier to work with, but gives rise to the same problems as multifilament nonabsorbable suture materials, namely wound infection due to capillary action and sinus tract formation when used internally.

Silk Modern silk sutures are composed of 70% natural silk and 30% extraneous materials (gum, beeswax and silicone).32 Silk is classified as a nonabsorbable suture material, but it loses 50% of its original strength within 1 month, and is completely absorbed by proteolysis in 2 years.26 Tensile strength is lost in 1 year.53 Silk has excellent handling characteristics and knot security, and is still occasionally used in oral surgery, but is known to cause substantial tissue inflammation. Host tissue reactions may lead to encapsulation by granulation tissue.57 Silk has high capillarity, and should generally be avoided in contaminated sites.

SUTURE SIZE Currently, the common standard for suture size diameter is that issued by the USP. Size is designated by a numerical code, 11–0 being the smallest size available and 6 the largest. The size of the suture material selected should correlate with the tensile strength of the tissue being sutured, and the smallest diameter suture sufficient to adequately appose the wound margins should be used to minimize the trauma incurred from the passage (friction) of the suture through the tissues and the foreign body reaction created by the material that is retained in the wound.58 Size 3–0 and 4–0 sutures are the most commonly used sizes for oral and maxillofacial surgical procedures in humans.58 In most dogs and cats, 5–0 suture material is indicated.

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SUTURE NEEDLES The modern suture needle is constructed of corrosion-resistant surgicalgrade stainless steel, and consists of three basic parts: attachment end (swaged or closed eye), body and needle point. Needles for use in oromaxillofacial surgery are of the swaged-on variety, where the needle has been permanently crimped onto the suture material, as swaged needles facilitate suture handling and reduce tissue trauma during suturing compared to eyed needles.58 The body shape of the needle may be straight, curved or a combination of both (curved-ended straight) (Fig. 7.1). Needles are further divided into cuticular and plastic varieties; the latter is sharpened 36 times, and is designed for cosmetic closures.59 Selection of needle shape is based on accessibility of the area to be sutured and surgeon’s preference. For the purposes of oromaxillofacial surgery, the 3 8 -circle needle is the most commonly used, as it requires significantly less wrist pronation and supination in comparison to the other commonly used needle in veterinary medicine ( 1 2 -circle). As a general rule, curved needles with a comparatively greater arc ( 1 2 - or 5 -circle) are more suited for suturing small, deep wounds in confined 8 areas (e.g., vestibule or caudal oropharynx).59 Cutting, tapered and tapercut are the three basic types of needle points (Fig. 7.1). As their name suggests, cutting needles possess sharp edges (two opposing cutting edges and a third cutting edge along the curvature of the needle) that facilitate penetration through tough keratinized tissues such as the gingiva or skin. Cutting needles may be further subdivided

into conventional- and reverse-cutting needles. Although both are triangular in cross-section, the reverse-cutting needle has a flat surface along its inner curvature; preventing the inadvertent cutting of tissue ‘cut-out’ as the needle is passed through tissue. The reverse-cutting shape also increases the strength of the needle by 32%.59 Because of the predisposition for ‘cut-out’ with conventional-cutting needles, their use is limited within the oral cavity, and the reverse-cutting needle is the most commonly selected needle for general use in dentistry and oromaxillofacial surgery. Tapered point needles are round in cross-section, and result in less tissue damage than cutting point needles, but are poorly suited for use in tough tissues, such as gingiva. Tapercut needles combine the cutting action of the reverse-cutting needle at its tip and the round body of the taper for atraumatic passage through delicate tissues. The tapercut needle is recommended for use in mucogingival surgery.

SUTURE RECOMMENDATIONS FOR SPECIFIC TISSUES Intraoral tissue Size 5–0 Monocryl and Vicryl Rapide are currently the most compatible suture materials for intraoral use. For vestibular flap closure following maxillectomy, however, polypropylene is recommended.60 Both Monocryl and Vicryl Rapide have rapid absorption times that

A

B

C

D

E

Fig. 7.1  Shapes of surgical needles and types of needle points. (A) Straight needle; (B) Conventional-cutting 3 -circle needle; (D) Tapered 1 -circle; (E) Tapercut 5 -circle needle. 8 2 8

74

1 4

-circle needle; (C) Reverse-cutting

Suture materials and biomaterials approximate the optimum time for removal of nonabsorbable suture materials. The benefits of Monocryl include improved tensile strength, knot security, smoothness and minimal tissue reactivity, previously found only in synthetic monofilament nonabsorbable suture materials. Vicryl Rapide offers the improved handling characteristics of a multifilament, but has a rougher surface and less initial tensile strength, and is more expensive and reactive than Monocryl.54

Skin and subcutaneous tissue The closure of facial skin wounds in the dog or cat is best performed with size 4–0 synthetic monofilament nonabsorbable suture materials such as nylon or polypropylene. A simple interrupted suture pattern is recommended for the most cosmetic closure.26 Skin sutures placed in areas other than the face are traditionally removed at between 3 and 10 days.59 Facial skin sutures should be removed in 4 to 6 days to prevent epithelialization of the suture track.59 The subcutaneous tissues should be approximated with size 4–0 synthetic absorbable suture in a running continuous suture pattern. The use of a continuous suture pattern has the advantage of reducing the quantity of suture buried in the wound.

SURGICAL ADHESIVE TAPE Cutaneous tapes (Steri-Strips, 3M, St. Paul, MN) are microporous surgical adhesive tapes with a backing of viscous rayon fibers coated with an acrylic copolymer, and are available in 1 8 -, 1 4 - and 1 2 -inch wide strips.57 The closure of skin wounds with adhesive tape results in excellent wound healing because the skin is not penetrated with a needle, and there is less intrinsic tension on the wound.26 Approximation of deep tissues cannot be achieved with tape alone, and tape closure is often combined with subcuticular running or interrupted sutures.26,57 In animals, however, these materials have found little or no application because they are easily removed by the patient. Tincture of benzoin can be applied to the skin surface to enhance adhesion.26

SURGICAL STAPLES Skin clips or staples are useful to expedite closure of scalp or abdominal wounds where cosmesis is less of a concern.57 Staples maintain wound edges in eversion, but may result in necrosis and edema if used with excessive pressure.57

Chapter

|7|

Fibrin tissue adhesive Tisseel VH fibrin sealant (Tisseel VH, Baxter Healthcare Corporation, Westlake Village, CA) is a combination of human fibrinogen and bovine thrombin applied with a sterile delivery device.65 Within 3 to 5 minutes of delivery a solid fibrin clot forms that firmly adheres to soft tissues and promotes hemostasis. It is fully absorbed within 10 to 14 days. It has been used extensively in human surgery, including maxillofacial surgery. Applications include mucogingival flap surgery, cancellous bone grafts, cleft palate repair and oronasal fistula closure.65,66 It is especially useful for closure of extraction wounds or following cyst enucleation in patients with coagulopathies.67 Fibrin adhesives do not interfere with wound healing and may, in fact, promote healing.65,68 Autologous preparations of fibrin sealants may be prepared by centrifugation of a patient’s own whole blood or, if larger quantities are desired, from a cryoprecipitate. As a bioadhesive for the repair of oral mucosal defects, autologous fibrin sealants have been shown to be safe and well-tolerated in cats.69 Similar to its xenogenous counterpart, autologous fibrin sealants may be used as a hemostatic, but also as an promoter of bone graft healing.70–72 The substrate provided by the combined interaction of fibronectin, fibrin and factor XIII encourages the migration and growth of mesenchymal cells, accelerates revascularization and slows the multiplication of microorganisms.70 Healing is accelerated with factor XIII, and fibroblast and osteoblast growth are stimulated by fibrin.70,73,74 Autologous platelet-rich plasma gel is a modification of autologous fibrin sealants that is formed by mixing platelet-rich plasma from centrifuged autologous whole blood with thrombin and calcium chloride.75 The primary difference between fibrin sealants and platelet-rich plasma gel is the higher concentration of platelets and a native concentration of fibrinogen in the latter.75

BIOMATERIALS FOR HEMOSTASIS Hemorrhage following flap reflection and exodontia can usually be controlled with aspiration and pressure with moistened gauze, but slow, persistently oozing lesions may require the use of a hemostatic agent. Many hemostatic agents are also used as extraction socket dressings to reduce the volume of the blood clot that is formed and the chance of premature clot dissolution.76 These agents include bone wax, absorbable gelatin sponge, oxidized cellulose, oxidized regenerated cellulose, microfibrillar collagen and hemostatic sealants.

Bone wax TISSUE ADHESIVES Cyanoacrylates Cyanoacrylates (Ethibond Excel, Ethicon, Inc., Somerville, NJ) are liquid adhesives that polymerize in the presence of moisture, and have been used as hemostatic dressings for tongue lacerations, extraction wounds and periodontal surgery.61–63 Cyanoacrylates are well tolerated by oral tissues, promote healing, and may have bacteriostatic properties.63 The butyl and isobutyl cyanoacrylates are the most suitable for use in the oral cavity, and the isobutyl form is the least cytotoxic.39,64 Butyl or isobutyl cyanoacrylates that are applied to mucogingival tissues are exfoliated in 4 to 7 days; however only partial phagocytosis of the adhesive occurs when used in deeper tissues, and may result in granuloma formation.39

The present-day formulation for bone wax is a highly purified beeswax that contains isopropyl palmitate as a softening and conditioning agent.77 The wax functions as a mechanical hemostatic by blocking the vascular openings with plugs of blood and wax.78 Bone wax is especially useful as a hemostatic during periapical surgery.77 After hemostasis has been achieved, the bone wax should be removed, as the retained wax will initiate an intense foreign body reaction, characterized by giant cells, plasma cells and fibrous granulation tissue, that will inhibit osteogenesis.79,80

Absorbable gelatin sponge Gelfoam (Gelfoam, Pharmacia & Upjohn, Kalamazoo, MI) is a porous matrix gelatin sponge prepared from partially hydrolyzed pork skin that is intended for use as a hemostatic agent. Gelfoam is provided

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by the manufacturer in a powder that forms a paste when mixed with a sterile sodium chloride solution. The gelatin sponge is applied directly to the bleeding surface, and is absorbed in 4 to 6 weeks.81 Due to the potential for embolization, Gelfoam should be used with caution in intravascular compartments. Cube-sized gelatin sponges (Vetspon, Novartis Animal Health US Inc., Greensboro, NC) designed for use in extraction sockets are also available. The use of Gelfoam in extraction sockets is controversial, and has actually been shown to block cancellous bone replacement in dogs.82 It may also potentiate bacterial growth and serve as a nidus for infection and abscess formation.

Oxidized cellulose Oxycel (Oxycel, Becton Dickinson and Company, Franklin Lakes, NJ) is a chemically altered form of surgical gauze that functions as an artificial clot.81 Oxycel should be applied dry and removed from the wound prior to closure. Oxycel inhibits osteogenesis and epithelialization, and should not be used as a surface dressing or placed adjacent to bone.81 Oxycel will resorb to completion in 1 to 6 weeks.81

Oxidized regenerated cellulose Surgicel (Surgicel, Johnson & Johnson, New Brunswick, NJ) is an absorbable glucose polymer-based sterile knitted fabric that acts as a matrix for clot formation and as a clot stabilizer.82 Surgicel is prepared by the oxidation of regenerated cellulose, and its function as a hemostatic is dependent upon the bonding of hemoglobin to oxycellulose.82 Surgicel is resorbed in 7 to 14 days with minimal inflammation, but can swell by up to 135%, resulting in patient discomfort if used as an extraction site packing material.83 Surgicel has been marketed to control capillary, venous and small arterial hemorrhage, and, because it does not impede epithelialization, can be used as a surface dressing. Surgicel is bactericidal to a wide range of Gram-negative and Grampositive aerobes and anaerobes, and has been used successfully as a scaffolding material to fill bony defects (e.g., small to moderate-sized clefts of the palate).84,85

Microfibrillar collagen Avitene (Avitene, Davol, Inc., Cranston, RI) is an effective hemostatic agent for use on bleeding surfaces and in extraction sockets that is prepared from edible bovine corium as a water-insoluble, partial acid salt of natural collagen.86 This microfibrillar collagen product is also useful in the face of certain clotting factor deficiencies and heparinization, and has been reported to shorten the reaction time of the intrinsic clotting pathway by 60%.87 Avitene, however, does not accelerate

new bone formation when implanted in bone defects, and is more prone to bacterial contamination than oxidized cellulose.86,88

Thrombin-based hemostatic agents Bovine-derived thrombin is available in liquid or powder form as a topical hemostat. Thrombin is an enzyme that is active at the end of the coagulation cascade that converts fibrinogen to fibrin. Thrombin products bypass the need for functional platelets, and are useful in thrombocytopenic or thrombocytopathic patients. Since the thrombin is bovine derived, bovine thrombin should be avoided in patients with documented allergic reactions to bovine products.81 The significance of antibody development to bovine thrombin in veterinary patients is unknown. Synthetic alternatives to bovine thrombin, such as thrombin receptor agonist peptide-6 (TRAP), a synthetic hexapeptide that mimics the effects of thrombin, have been investigated.90 FloSeal (FloSeal, Baxter Healthcare Corporation, Westlake Village, CA) is a granular cross-linked collagen-derived matrix that is combined with thrombin to create a flowable gel. In comparison to other topical hemostats (Gelfoam and Surgicel), FloSeal granules swell by only 10–20% upon contact with blood, decreasing patient discomfort when used in extraction sockets. The thrombin that is incorporated with the FloSeal granules converts fibrinogen into a fibrin polymer that forms a clot surrounding the collagen-derived matrix. FloSeal is completely resorbed by the body in 6 to 8 weeks. In a comparison study of FloSeal and Gelfoam plus thrombin for the control of intraoperative hemorrhage, FloSeal provided more rapid and effective hemostasis, 93% of first-site applications, compared to 76% for Gelfoam plus thrombin.91

Microporous polysaccharide hemospheres Microporous polysaccharide hemosphere (MPH) powder (Arista AH, Medafor, Inc., Minneapolis, MN) is a hemostatic wound dressing composed of purified cross-linked starch (potato) particles ranging in size from 10 to 200 micrometers in diameter.92 When topically applied to a wound bed, the fluid components of blood (low molecular weight) are absorbed into the controlled-size pores of the particles.92 The high-molecular-weight solids of blood (platelets, red blood cells, albumin, thrombin and fibrinogen) are concentrated between and on the surface of the particles to provide a viscous barrier to blood seepage.92 Hemostasis with MPH can occur as quickly as 30 seconds. MPH particles are degraded by enzymatic hydrolysis within 24 to 48 hours by endogenous alpha amylase.92 Potential applications in veterinary oral surgery include placement in areas of diffuse hemorrhage such as oozing extraction sockets and nasal conchae bleeding following maxillectomy.

REFERENCES 1. McCaul LK, Bagg J, Jenkins WM. Rate of loss of irradiated polyglactin 910 (Vicryl Rapide) from the mouth: a prospective study. Br J Oral Maxillofac Surg 2000; 38:328–30. 2. Lilly GE. Reaction of oral tissues to suture materials. Oral Surg Oral Med Oral Pathol 1968;26:128–33. 3. Macht SD, Krizek TJ. Sutures and suturing – current concepts. J Oral Surg 1978;36: 710–12.

76

4. Lilly GE, Armstrong JH, Salem JE, et al. Reaction of oral tissues to suture materials. II. Oral Surg Oral Med Oral Pathol 1968; 26:592–9. 5. King RC, Crawford JJ, Small EW. Bacteremia following intraoral suture removal. Oral Surg Oral Med Oral Pathol 1988;65:23–8. 6. Silverstein LH, Christensen GJ. Principles of dental suturing: the complete guide to surgical closure. Mahway, NJ: Montage Media Corp; 1999. p. 8–11.

7. Selvig KA, Torabinejad M. Wound healing after mucoperiosteal surgery in the cat. J Endod 1996;22:507–15. 8. Mittleman HR, Toto PD, Sicher H. Healing in human attached gingiva. Periodontics 1964;2:106–14. 9. Harrison JW, Jurosky KA. Wound healing in the tissues of the periodontium following periradicular surgery. I. The incisional wound. J Endod 1991;17: 425–35.

Suture materials and biomaterials 10. Harrison JW. Healing of surgical wounds in oral mucoperiosteal tissues. J Endod 1991;17:401–8. 11. Chu CC, Kizil Z. Quantitative evaluation of stiffness of commercial suture materials. Surg Gynecol Obstet 1989;168:233–8. 12. Blomstedt B, Osterberg B, Bergstrand A. Suture material and bacterial transport. An experimental study. Acta Chir Scand 1977; 143:71–3. 13. Metz SA, Chegini N, Masterson BJ. In vivo and in vitro degradation of monofilament absorbable sutures, PDS and Maxon. Biomaterials 1990;11:41–5. 14. Katz S, Izhar M, Mirelman D. Bacterial adherence to surgical sutures. A possible factor in suture induced infection. Ann Surg 1981;194:35–41. 15. Fossum TW, Hedlund CS, Hulse DA, et al. Small animal surgery. 2nd ed. St. Louis, MO: Mosby; 2002. p. 43–59. 16. van Rijssel EJ, Brand R, Admiraal C, et al. Tissue reaction and surgical knots: the effect of suture size, knot configuration, and knot volume. Obstet Gynecol 1989; 74:64–8. 17. Holmlund DE. Knot properties of surgical suture materials. A model study. Acta Chir Scand 1974;140:355–62. 18. Stashak TS, Yturraspe DJ. Considerations for selection of suture materials. Vet Surg 1978;2:48–55. 19. Thacker JG, Rodeheaver G, Moore JW, et al. Mechanical performance of surgical sutures. Am J Surg 1975;130:374–80. 20. Herrmann JB. Tensile strength and knot security of surgical suture materials. Am Surg 1971;37:209–17. 21. Rosin E, Robinson GM. Knot security of suture materials. Vet Surg 1989;18: 269–73. 22. Otten JE, Wiedmann-Al-Ahmed M, Jahnke H, et al. Bacterial colonization on different suture materials – a potential risk for intraoral dentoalveolar surgery. J Biomed Mater Res B Appl Biomater 2005;74: 627–35. 23. Marsh PD. Plaque as a biofilm: Pharmacological principles of drug delivery and action in the sub- and supragingival environment. Oral Dis 2003;1:16–22. 24. Giglio JA, Rowland RW, Dalton HP, et al. Suture removal-induced bacteremia: A possible endocarditis risk. J Am Dent Assoc 1992;123:69–70. 25. Hendler BH, Kempers KG. Soft tissue injuries. In: Fonseca RJ, editor. Oral and maxillofacial surgery. Philadelphia, PA: WB Saunders Co; 2000. p. 341–68. 26. Boothe Jr HW. Selecting suture materials for small animal surgery. Compend Contin Educ Pract Vet 1998;20:155–63. 27. Chu CC, Moncrief G. An in vitro evaluation of the stability of mechanical properties of surgical suture materials in various pH conditions. Ann Surg 1983; 198:223–8.

28. Tomihata K, Suzuki M, Ikada Y. The pH dependence of monofilament sutures on hydrolytic degradation. J Biomed Mater Res 2001;58:511–18. 29. Rockwood DP, Miller RI. Characteristics of currently available suture materials. Gen Dent 1988;36:489–93. 30. Shaw RJ, Negus TW, Mellor TK. A prospective clinical evaluation of the longevity of resorbable sutures in oral mucosa. Br J Oral Maxillofac Surg 1996; 34:252–4. 31. Chung H, Weinberg S. Suture materials in oral surgery: a review. Oral Health 1978; 68:31–4. 32. Horton CE, Adamson JE, Mladick RA, et al. Vicryl synthetic absorbable sutures. Am Surg 1974;40:729–31. 33. Laufman H, Rubel T. Synthetic absorbable sutures. Surg Gynecol Obstet 1977;145:597–608. 34. McGeehan D, Hunt D, Chaudhuri A, et al. An experimental study of the relationship between synergistic wound sepsis and suture materials. Br J Surg 1980;67:636–8. 35. Wallace WR, Maxwell GR, Cavalaris CJ. Comparison of polyglycolic acid suture to black silk, chromic and plain catgut in human oral tissues. J Oral Surg 1970;28: 739–46. 36. Moser JB, Lautenschlager EP, Horbal BJ. Mechanical properties of polyglycolic acid sutures in oral surgery. J Dent Res 1974;53:804–8. 37. Lilly GE, Osbon DB, Hutchinson RA, et al. Clinical and bacteriologic aspects of polyglycolic acid sutures. J Oral Surg 1973;31:103–5. 38. Levin MP. Periodontal suture materials and surgical dressings. Dent Clin North Am 1980;24:767–81. 39. Duprez K, Bilweis J, Duprez A, et al. Experimental and clinical study of fast absorption cutaneous suture material. Ann Chir Main 1988;7:91–6. 40. Martelli H, Catena D, Rahon H, et al. Skin sutures in pediatric surgery. Use of a fast-resorption synthetic thread. Presse Med 1991;20:2194–8. 41. Aderriotis D, Sandor GK. Outcomes of irradiated polyglactin 910 Vicryl Rapide fast-absorbing suture in oral and scalp wounds. J Can Dent Assoc 1999;65:345–7. 42. Barbolt TA. Chemistry and safety of triclosan, and its use as an antimicrobial coating on Coated VICRYL* Plus Antibacterial Suture (coated polyglactin 910 suture with triclosan). Surg Infect (Larchmt) 2002;3(Suppl 1):S45–53. 43. Gilbert P, McBain AJ. Literature-based evaluation of the potential risks associated with impregnation of medical devices and implants with triclosan. Surg Infect (Larchmt) 2002;3(Suppl 1):S55–63. 44. Storch M, Scalzo H, Van Lue S, et al. Physical and functional comparison of Coated VICRYL* Plus Antibacterial Suture (coated polyglactin 910 suture with

Chapter

|7|

triclosan) with Coated VICRYL* Suture (coated polyglactin 910 suture). Surg Infect (Larchmt) 2002;3(Suppl 1):S65–77. 45. Rothenburger S, Spangler D, Bhende S, et al. In vitro antimicrobial evaluation of Coated VICRYL* Plus Antibacterial Suture (coated polyglactin 910 with triclosan) using zone of inhibition assays. Surg Infect (Larchmt) 2002;3(Suppl 1):S79–87. 46. Edmiston CE, Seabrook GR, Goheen MP, et al. Bacterial adherence to surgical sutures: Can antibacterial-coated sutures reduce the risk of microbial contamination. J Am Coll Surg 2006; 203:481–9. 47. Katz AR, Mukherjee DP, Kaganov AL, et al. A new synthetic monofilament absorbable suture made from polytrimethylene carbonate. Surg Gynecol Obstet 1985;161: 213–22. 48. DeNardo GA, Brown NO, Trenka-Benthin S, et al. Comparison of seven different suture materials in the feline oral cavity. J Am Anim Hosp Assoc 1996;32:164–72. 49. Quayle AA, El-Badrawy H. Clinical and experimental studies with resorbable transosseous ligature. Br J Oral Maxillofac Surg 1984;22:24–9. 50. Rodeheaver GT, Powell TA, Thacker JG, et al. Mechanical performance of monofilament synthetic absorbable sutures. Am J Surg 1987;154:544–7. 51. Bezwada RS, Jamiolkowski DD, Lee I-Y, et al. Monocryl suture, a new ultra-pliable absorbable monofilament suture. Biomaterials 1995;16:1141–8. 52. LaBagnara Jr J. A review of absorbable suture materials in head & neck surgery and introduction of Monocryl: a new absorbable suture. Ear Nose Throat J 1995;74:409–15. 53. Banche G, Roana J, Mandras N, et al. Microbial adherence on various intraoral suture materials in patients undergoing dental surgery. J Oral Maxillofac Surg 2007;65:1503–7. 54. Rodeheaver GT, Borzelleca DC, Thacker JG, et al. Unique performance characteristics of Novafil. Surg Gynecol Obstet 1987;164:230–6. 55. Pinheiro AL, de Castro JF, Thiers FA, et al. Using Novafil: would it make suturing easier? Braz Dent J 1997;8:21–5. 56. Holt GR, Holt JE. Suture materials and techniques. Ear Nose Throat J 1981;60: 12–8. 57. Selvig KA, Biagiotti GR, Leknes KN, et al. Oral tissue reactions to suture materials. Int J Periodont Rest Dent 1998;18:474–87. 58. Hupp JR. Principles of surgery In: Peterson LJ, Ellis III E, Hupp JR et al, editors. Contemporary oral and maxillofacial surgery. 4th ed. St. Louis, MO: Mosby; 2003. p. 42–8. 59. Powers MP, Beck BW, Fonseca RJ. Management of soft tissue injuries In: Fonseca RJ, Walker RV, Betts NJ et al, editors. Oral and maxillofacial trauma.

77

Section

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Philadelphia, PA: WB Saunders Co; 1997, p. 792–854. 60. Salisbury SK, Thacker HL, Pantzer EE, et al. Partial maxillectomy in the dog: comparison of suture materials and closure techniques. Vet Surg 1985; 14:265–76. 61. Ochstein AJ, Hansen NM, Swenson HM. A comparative study of cyanoacrylate and other periodontal dressings on gingival surgical wound healing. J Periodontol 1969;40:515–20. 62. Bhaskar SN, Jacoway JR, Margetis PM, et al. Oral tissue response to chemical adhesives (cyanoacrylates). Oral Surg 1966;22:394–404. 63. Bhaskar SN, Frisch J, Cutright DE, et al. Effect of butyl cyanoacrylate on the healing of extraction wounds. Oral Surg Oral Med Oral Pathol 1967;24:604–16. 64. Forrest JO. The use of cyanoacrylates in periodontal surgery. J Periodontol 1974;45:225–9. 65. Fattahi T, Mohan M, Caldwell GT. Clinical applications of fibrin sealants. J Oral Maxillofac Surg 2004;62:218–24. 66. Davis BR, Sandor GK. Use of fibrin glue in maxillofacial surgery. J Otolaryngol 1998; 27:107–12. 67. Bodner L, Weinstein JM, Baumgarten AK. Efficacy of fibrin sealant in patients on various levels of oral anticoagulant undergoing oral surgery. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;86:421–4. 68. Yucel EA, Oral O, Olgac V, et al. Effects of fibrin glue on wound healing in oral cavity. J Dent 2003;31:569–75. 69. Gaboriau HP, Belafsky PC, Pahlavan N, et al. Closure of mucosal defects over exposed mandibular plates using fibrin glue. Arch Facial Plast Surg 1999;1: 191–4. 70. Tayapongsak P, O’Brien DA, Monteiro CB, et al. Autologous fibrin adhesive in mandibular reconstruction with particulate cancellous bone and marrow. J Oral Maxillofac Surg 1994;52:161–6.

78

71. Wepner F, Fries R, Platz H. The use of the fibrin adhesion system for local hemostasis in oral surgery. J Oral Maxillofac Surg 1982;40:555–8. 72. Carter G, Goss AN, Lloyd J, et al. Local haemostasis with autologous fibrin glue following surgical enucleation of a large cystic lesion in a therapeutically anticoagulated patient. Br J Oral Maxillofac Surg 2003;41:275–6. 73. Yucel EA, Oral O, Olgac V, et al. Effects of fibrin glue on wound healing in oral cavity. J Dent 2003;31:569–75. 74. Matras H. Fibrin seal: the state of the art. J Oral Maxillofac Surg 1985;43:605–11. 75. Whitman DH, Berry RL, Green DM. Platelet gel: an autologous alternative to fibrin glue with applications in oral and maxillofacial surgery. J Oral Maxillofac Surg 1997;55:1294–9. 76. Olson RA, Roberts DL, Osbon DB. A comparative study of polylactic acid, Gelfoam, and Surgicel in healing extraction sites. Oral Surg Oral Med Oral Pathol 1982;53:441–9. 77. Selden HS. Bone wax as an effective hemostat in periapical surgery. Oral Surg Oral Med Oral Pathol 1970;29:262–4. 78. Geary JR, Frantz VK. New absorbable hemostatic bone wax. Ann Surg 1950; 132:1128–37. 79. Finn MD, Schow SR, Schneiderman ED. Osseous regeneration in the presence of four common hemostatic agents. J Oral Maxillofac Surg 1992;50:608–12. 80. Ibarrola J, Bjorenson J, Austin B, et al. Osseous reactions to three hemostatic agents. J Endod 1985;11:75–83. 81. Klokkevold PR, Carranza FA, Takei HH. General principles of periodontal surgery. In: Newman MG, Takei HH, Carranza FA, editors. Carranza’s clinical periodontology. 9th ed. Philadelphia, PA: WB Saunders Co; 2002. p. 725–36. 82. Howard PE, Wilson JW, Ribble GA. Effects of gelatin sponge implantation in cancellous bone defects in dogs. J Am Vet Med Assoc 1988;192:633–7.

83. Halfpenny W, Fraser JS, Adlam DM. Comparison of 2 hemostatic agents for the prevention of postextraction hemorrhage in patients on anticoagulants. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;92:257–9. 84. Petersen JK, Krogsgaard J, Nielsen KM, et al. A comparison between 2 absorbable hemostatic agents: gelatin sponge (Spongostan) and oxidized regenerated cellulose (Surgicel). Int J Oral Surg 1984;13:406–10. 85. Thilander BL, Stenstrom SJ. Bone healing after implantation of some hetero- and alloplastic materials: an experimental study on the guinea pig. Cleft Palate J 1970;7:540–9. 86. Skoog T. The use of periosteum and Surgicel for bone restoration in congenital clefts of the maxilla. A clinical report and experimental investigation. Scand J Plast Reconstr Surg 1967;1: 113–30. 87. Hunt LM, Benoit PW. Evaluation of microcrystalline collagen preparation in extraction wounds. J Oral Surg 1976;34:407–14. 88. Abbott WM, Austen WG. Microcrystalline collagen as a topical hemostatic agent for vascular surgery. Surgery 1974;75: 925–33. 89. Scher KS, Coil JA, Jr. Effects of oxidized cellulose and microfibrillar collagen on infection. Surgery 1982;91:301–4. 90. Landesberg R, Burke A, Pinsky D, et al. Activation of platelet-rich plasma using thrombin receptor agonist peptide. J Oral Maxillofac Surg 2005;63:529–35. 91. Weaver FA, Hood DB, Zatina M, et al. Gelatin-thrombin-based hemostatic sealant for intraoperative bleeding in vascular surgery. Ann Vasc Surg 2002;16: 286–93. 92. Tan SR, Tope WD. Effectiveness of microporous polysaccharide hemospheres for achieving hemostasis in Mohs micrographic surgery. Dermatol Surg 2004;30:908–14.