Oral Surgery – Periodontal Surgery

Oral Surgery – Periodontal Surgery

Heidi B. Lobprise1 and Kevin Stepaniuk2

1 Main Street Veterinary Dental Clinic, Flower Mound, TX, USA

2 Veterinary Dentistry Education and Consulting Services, LLC, Ridgefield, WA, USA

10.1 Introduction

In Chapter 5 – Periodontology – the basic concepts of periodontal disease and management were discussed, including the steps of complete dental assessment, dental cleaning and polishing, and home care. The roles of host modulation in combination with professional care and cleaning outlined the efforts to help manage the patient’s inflammatory response to periodontal disease and how both aspects need to be addressed. Appropriate selection of antibiotics, including perioceutic therapy, was also discussed. This chapter continues periodontal treatment with the topics of periodontal surgery and other advanced therapies.

The goal of all periodontal therapy to arrest the progression of the disease is combined with efforts to minimize attachment loss, including efforts to eliminate periodontal pockets. Preservation of the periodontal tissues, with an emphasis on maintaining the attached gingiva (AG) and underlying tissues, is a primary objective of initial treatment, and efforts to restore or regenerate some of those lost tissues is possible in select cases.

10.1.1 Selection of Cases

The selection of cases, in fact, is a critical factor in determining which teeth should be treated and which teeth should be extracted. The opportunities to treat teeth with advanced lesions will be limitless, but several factors need to be considered, including the tooth/teeth, the patient and the client. Certainly, the extent and type of attachment loss on a tooth is evaluated closely, and the relative importance of the tooth can help determine if the effort is justified. Strategic teeth such as canines and carnassial teeth often deserve special consideration. Less strategic teeth, however, particularly those adjacent to the larger ones, may be selected for extraction to allow better access to the juxtaposed teeth for more effective treatment. Consideration of the quality of the tissues of attachment can influence prognosis as well. Toy breeds have been shown to have significantly thinner gingiva and alveolar bone than larger dogs and these dimensions may be predictors for the potential severity of the disease and can influence clinical outcome [1].

Advanced periodontal therapy will often result in longer and more frequent anesthetic episodes, so patients with increased anesthetic risks may be poor candidate choices. Extracting a potential source of chronic inflammation and infection may be preferable in those patients with ongoing systemic disease. Client education as to the importance of regular and effective home care and more frequent periodontal assessment may help identify those willing and able to commit to the extra work and financial investment to have satisfactory results.

Application of concepts and advanced treatments used in human dentistry has greatly enhanced the level of periodontal care we can provide our veterinary patients. Distinct differences in oral anatomy and function requires us to adjust definitions, classifications, and even anticipated prognoses for our patients. A shorter life span and the emphasis of function over aesthetics should make us question if a procedure that might be possible to perform would actually be best for the patient.

10.2 Goals of Periodontal Therapy

As stated in Chapter 5 – Periodontology – “The goal with periodontal disease is to stop the disease, minimize further attachment loss, and treat compromised teeth,” as well as to “remove the plaque biofilm” and eliminate pockets. Modulating the host response to “address the inflammatory response to the plaque biofilm” is important as well.

The efforts to minimize attachment loss are fundamental in attempting to keep optimal levels of the patient’s attached gingiva, periodontal ligament, alveolar bone and healthy cementum on the root. In Chapter 1 – Oral Anatomy and Physiology – “The attached gingiva is arranged as mucoperiosteum with direct attachment …. The width of the attached gingiva is important in planning periodontal treatment.” While a general guideline of needing a minimal width of attached gingiva for optimal health has been considered, in human patients with good, atraumatic oral hygiene, no minimum width of attached gingiva has been established as a necessary standard [2]. Such hygiene practices are unlikely to occur with veterinary patients, so the presence of keratinized gingiva (minimum of 2–3 mm of attached gingiva) can provide some level of protection.

Another specific consideration in periodontal therapy is to eliminate or minimize pockets, to facilitate healing and treatment. A variety of methods can minimize pocket depth, from reducing inflammation of soft tissue to excising excessive tissue or trying to build back tissues of attachment. Certainly, every effort at periodontal therapy includes the removal of any plaque biofilm or calculus, as well as necrotic or infected tissues in the area.

10.3 Evaluation/Classification of Disease

10.3.1 General Classification of Periodontal Disease

The basic definitions of the stages of periodontal disease are covered well in Chapter 5 – Periodontology – with specific references to the guidelines provided by the American Veterinary Dental College (AVDC). Typically, teeth in stage 3 to stage 4 periodontal disease have attachment loss significant enough to warrant advanced periodontal therapy, but some stage 2 teeth (up to 25% attachment loss) can be classified as stage 3 if stage 2 furcation involvement is present (F2) or as stage 4 with stage 3 furcation involvement (F3).

10.3.2 Attachment Loss Categorization

Determining both the extent and nature of attachment loss is critical in forming the appropriate treatment plan for the tooth or portion of the tooth. Measurement of all pockets/sulci, extent of gingival recession (GR) or marginal tissue recession (MTR), areas of root exposure and furcation involvement, tooth mobility, and evaluation of the remaining attached gingiva are critical parameters. Dental radiography and even advanced imaging will help determine the extent and type of periodontal bone loss (see Chapter 3 – Oral Radiology and Imaging).

Dividing the general groups of attachment loss or periodontal lesions into suprabony and intrabony (infrabony) highlights the special considerations when attachment loss extends apical to the alveolar bone height. In such lesions, there are both the challenges of access, as well as the opportunities for therapy. The descriptions of attachment loss in Chapter 5 include root exposure, suprabony pockets, intrabony(infrabony) pockets, and pseudopockets.

10.3.3 Suprabony Attachment Loss or Periodontal Lesion Suprabony Periodontal Pocket

If there is horizontal bone loss without loss of the gingiva or at a rate greater compared to the loss of gingiva, the progression of attachment loss proceeds through the junctional epithelium (JE) and causes a soft tissue pocket with the base of the pocket coronal to the alveolar bone. Pseudopocket

When there is gingival enlargement with no apical movement of the level of the JE or alveolar bone, the increased gingival height will give the appearance of periodontal pockets. Simple inflammation of the gingival margin can cause an increase in the “pocket” or sulcus depth, but with appropriate cleaning and therapy, the inflammation should subside and the sulcus depth can return to normal. True gingival enlargement (often termed gingival hyperplasia) will cause false pocket formation, which then requires treatment. Gingival Recession – Marginal Tissue Recession

The term gingival recession is used more commonly than MTR, but if the loss of soft tissue extends beyond the mucogingival junction (MGJ), then mucosal tissue is also lost. Multiple classifications of soft tissue loss have been established, most notably Miller’s Classification of MTR and Norland and Tarnow’s classification of the loss of interdental papilla tissue [3, 4]. A newer classification by Kumar includes additional parameters that are not defined well in the Miller classification [5]. These measurements are not always applicable to veterinary cases, as interdental architecture can be quite variable, but basic concepts of how the extent and pattern of attachment loss can affect prognosis can be extrapolated. Root Exposure and Furcation Involvement

If gingival tissue and alveolar bone height are both lost, there is exposure of the root apical to the neck of the tooth. This pattern is generally seen where there is horizontal bone loss around one tooth or several teeth, though focal clefts may occur. In dogs, a Stillman’s cleft (mucogingival triangular‐shaped defect on the buccal surface of a root can sometimes be found on the maxillary canine tooth [6]. If the attachment loss is pronounced at a multirooted tooth, then furcation involvement may be present (Table 10.1) [7]. Any level of furcation involvement can impact the prognosis for the tooth, as they can be more challenging to treat and to provide effective home care.

Table 10.1 Furcation involvement/exposure index – FI [7].

Stage 1 F1, furcation involvement Exists when a periodontal probe extends less than halfway under the crown in any direction of a multirooted tooth with attachment loss.
Stage 2 F2, furcation involvement Exists when a periodontal probe extends greater than halfway under the crown of a multirooted tooth with attachment loss but not through and through.
Stage 3 F3, furcation involvement Exists when a periodontal probe extends under the crown of a multirooted tooth, through and through from one side of the furcation out the other.

In some older cats, chronic osteitis and supereruption of the teeth can also result in root exposure of the canine teeth (particularly the maxillary canines), but is not due to gingival and alveolar recession. These teeth may also have additional pocket formation, so full assessment is needed.

10.3.4 Intrabony (Infrabony) Attachment Loss

When attachment loss of alveolar bone extends in a vertical or angular fashion down the root of a tooth, the intrabony defect has a base that is apical to the surrounding bone margin. This bone loss adjacent to a tooth root is further defined by the pattern of remaining “walls” of bone that surround the pocket. Each pattern – one‐wall, two‐wall, three‐wall, and four‐wall (cup or crater defect) – necessitates selection of appropriate treatment approaches for optimal results. From Chapter 5:

  • Three‐wall infrabony pocket. The defect is formed by the root acting as one wall and three osseous surfaces as the other walls (Figure 10.1a).
  • Two‐wall infrabony pocket. Extends interdentally to communicate with the root of an adjacent tooth; the two tooth surfaces make up two walls and the other two walls are formed by bone on the labial and lingual surfaces (Figure 10.1b). The two walls can also be formed if there is bony dehiscence of a buccal or lingual wall of a three‐walled defect (Figure 10.1c).
  • One‐wall infrabony pocket. The two‐wall infrabony extends to include destruction of the labial or lingual osseous wall resulting in replacement by connective and inflammatory tissue and leaving only one bony surface (Figure 10.1d).
  • Cup defect or four‐wall infrabony pocket. A defect surrounding the tooth like a moat (Figure 10.1e).
  • Combined osseous defect. Number of walls in the apical portion of the defect is often greater than in its occlusal portion [8].
Image described by caption and surrounding text.

Figure 10.1 (a) Three‐wall defect; (b) two‐wall (crater) defect between two teeth; (c) two‐wall defect – dehiscence of three‐wall defect; (d) one‐wall defect; (e) four‐wall (circumferential) defect.

Source: Illustration by Josephine Banyard, DVM, DAVDC, adapted from First Edition.

Bone loss of the thin cortical bone can occur in a focal defect through the overlying periosteum and gingiva as a fenestration, and if this loss extends to the alveolar margin, then a dehiscence defect is present. Such defects may not be readily apparent radiographically and are found once the gingival flap is elevated.

10.4 Periodontal Healing and Treatment Planning

When the complete examination, including radiographs, has mapped out the picture of altered tissues, various factors have to be considered in the process of selecting the course of action.

10.4.1 Initial Prognostic Factors

Keratinized gingiva, as a band of attached gingiva, can be a factor in determining prognosis, particularly if oral hygiene will not be optimal. Teeth with a short root in comparison to crown size may also be a factor that put the tooth at risk for treatment failure, due to the decrease in reserve functional tissues of attachment [9]. Decreased attachment surface area and loss of tissue can lead to mobility, which is distinctly a prognostic risk, as the mobility is not likely to be corrected [9]. While mobile mandibular incisors have been treated successfully in dogs with a periodontal splint [10], the extent of care that is needed with subsequent periodontal therapy and continued home care is often unattainable, so extractions are usually done.

The biggest factor in determining prognosis in the veterinary dental field is likely to be the effectiveness of oral hygiene care that can be provided. Rarely does the patient–client combination exist that can guarantee meticulous control of plaque bacteria, so most procedures should be planned with the concept that a lower level of hygiene will be the reality of the situation compared to human periodontal patients.

10.4.2 Healing Goals/Rationale for Treatment

All efforts in periodontal therapy are aimed at restoring the function, if not the anatomy, of the periodontal structures [11]. Epithelial surfaces should be restored and connective tissue returned such that root cementum is predominantly attached to bone via the periodontal ligament. In addition, supporting bone height is preferred. The balance between formation and resorption of osseous tissues should be maintained. Depending on what tissues remain, and in what state, along with the availability of special materials and techniques, the goals for treatment will help maximize these tissue responses.

The American Association of Periodontists provide a glossary with some of the following terms [12]:

  • Repair. Healing of a wound by tissue that does not fully restore the architecture or function of the part.
  • Regeneration. The reproduction or reconstitution of a lost or injured tissue.
  • Periodontal regeneration. The restoration of lost periodontium or supporting tissues, includes the formation of new alveolar bone, new cementum (NC) and new periodontal ligament (PDL).
  • New attachment. The union of connective tissue or epithelium with a root surface that has been deprived of its original attachment apparatus. This new attachment may be epithelial adhesion or connective tissue adaptation or attachment and may include new cementum.
  • Reattachment. Reunion of epithelial and connective tissue with a root surface (not exposed by disease, but by treatment) [11].
  • Guided tissue regeneration. Describes procedures attempting to regenerate lost periodontal structures through differential tissue responses and typically refers to regeneration of periodontal attachment. Barrier techniques are used for excluding connective tissue and gingiva from the root in the belief that they interfere with regeneration.

In our efforts of periodontal therapy, we remove irritants (bacteria, granulation tissue, debris) that can interfere with natural regeneration and we can encourage selected tissues (PDL, bone, cementum) by excluding gingival connective tissue and epithelial cells into the region by use of barriers and membranes. Melcher’s concept of “compartmentalization,” dividing these tissues into groups, helps us anticipate the healing outcome based on the sequence of events [13]. If the more rapidly growing epithelial cells are allowed to repopulate the defect (they migrate approximately 10 times faster than other periodontal cell type [14], there will be a long junctional epithelium (LJE). With gingival connective tissue healing, the collagen fibers will be parallel to the tooth surface with remodeling of the bone but no attachment to the cementum, with potential exposure for resorption [15]. Repopulation with osteoblasts will at times result in ankylosis and root resorption, while in the presence of PDL cells there can be new formations of cementum and the PDL [11]. In studies of space‐providing membranes, wound stability and space provision are critical to allow the repopulation of the defect with bone and periodontal ligament [16]. Studies have also shown that the “migration rate of periodontal ligament cells is at least as high as that of bone” [15], with possibly even a higher maturation or regeneration potential [16].

10.4.3 Host Modulation Therapy (HMT)

As the understanding of how a host’s immunoinflammatory response determines the extent and severity of tissue destruction, part of any periodontal management should include considerations of modulating this host response [17]. The discussion of host modulation therapy (HMT) was briefly covered in Chapter 5 – Periodontology. The term “perioceutic” was once trademarked, but is now used to discuss the use of pharmacotherapeutic agents (antimicrobials and HMT) in periodontal management. The key is to help control excessive immune and inflammatory response without negating the beneficial effects in response to the bacterial presence. Systemic HMT

Matrix metalloproteinases (MMPs) can degrade the extracellular matrix and modify cytokines and osteoclasts [18]. If unchecked by endogenous inhibitors, substantial tissue destruction can occur. The most common synthetic MMP inhibitor is a subantimicrobial dose of doxycycline (subantimicrobial dose doxycycline (SDD) – doxycycline hyclate 20 mg), used twice daily in humans for at least three months and up to a maximum of nine months [19]. Doxycycline is more effective in inhibiting collagenases than tetracycline or minocycline [20].

Non‐steroidal anti‐inflammatory drugs (NSAIDS) have been shown to inhibit prostaglandin synthesis and slow the rate of alveolar bone loss. This occurs with daily therapy over time, though, if stopped, not only can the improvement be stopped but a rebound effect with accelerated bone loss may occur [19]. Potential side effects of prolonged NSAID therapy should also be considered.

Endogenous lipoxins (LX) can reduce neutrophil infiltration, block cytokines and reactive oxygen species generation [17]. Lipid‐inflammatory mediators (resolvins, protectins, maresins) can also inhibit neutrophil recruitment, helping to counter‐regulate excessive acute inflammation and may help stimulate events that lead to resolution of inflammation [18]. Milk from hyperimmunized cows (HIMF) provides a substance that can decrease the impact of hyperactive neutrophils [21], decrease their recruitment [22], and have an impact in the dysbiotic oral community in periodontitis [23]. Cytokine antagonists bind against specific sites, with multiple anticytokine antibody products available in human medicine [17].

Targeting and disrupting cell‐signaling pathways can help to inhibit the production of pro‐inflammatory cytokines or stimulate anti‐inflammatory cytokine production [17]. Pentoxifylline (PTX) can inhibit cytokine synthesis, particularly tumor necrosis factor (TNF) [24]. Endogenous osteoprotegrin can block the binding of RANKL to RANK (receptor activator of nuclear factor‐kappa B ± ligand) to support a better equilibrium between bone formation and bone destruction [25]. RANKL inhibitors in humans have demonstrated increased bone mineral density and decreased bone resorption [25].

Bisphosphonate compounds disrupt osteoclasts and may interfere with lysosomes, which can lead to a decrease in bone turnover as bone resorption is inhibited [19]. Anticollagenase activity has also been described [26]. In other species, an increase in bone density and decrease in alveolar bone resorption has been demonstrated [27, 28]. Unfortunately, with intravenous products and long‐term oral administration, a bisphosphonate‐related osteonecrosis of the jaw (BRONJ) has been reported in humans [29]. Likewise, bisphosphonates can cause severe deleterious bone‐related osteonecrosis of the jaw in dogs [30, 31]. There are discussions of cases in feline patients as well, but no peer‐reviewed publications are available to date.

Selective estrogen receptor modulators (SERM) and hormone replacement therapy (HRT) are based on osteoporotic effects due to a lack of estrogens in post‐menopausal women [17]. While estrogen may have bone‐sparing effects, the potential side effects of HRT is likely to negate its universal use.

Low levels of nitric oxide maintain homeostasis but when endotoxins increase, inducible nitric oxide synthase enzyme (iNOS), producing NO and peroxynitrite, DNA damage, protein damage and cytokine release may occur. Selective inhibition of iNOS, such as with mercaptoethylguanidine (MEG) has been shown to prevent alveolar bone resorption [32]. Local HMT

Local treatments that are used in periodontal pocket, particularly during surgical treatment, will be discussed in a later section. Other local medicaments may include oral rinse or mouthwashes with compounds such as NSAIDS (ketoprofen) or chlorotaurine [17]. Topical cimetidine has been shown to inhibit neutrophil chemotaxis and superoxide production, down‐regulating cytokines. It has even been shown to inhibit Porphyromonas gingivalis‐elicited periodontal inflammation, modulating tissue destruction and influencing cell population in the infiltrate [33].

10.4.4 Periodontal Treatment Equipment [34]

In addition to some of the basic periodontal equipment discussed in Chapter 5 – Periodontology – probe/explorer, scaler, and curette, additional pieces will facilitate surgical periodontal efforts. Heavier curettes (Prichard curette) and sickle scalers (Ball scaler) can be used to surgically remove tough fibrous and granulation tissue. Gingivectomy knives such as the Kirkland knife provides an entire cutting edge along the periphery of the blade, either single‐ended or double‐ended. For interdental areas, an Orban knife or Merrifield knife has a cutting edge on each side of its spear‐shaped blade (again, single‐ or double‐ended).

The narrow 15C surgical blade can be used to follow scalloped contours, or in interdental spaces. The beak‐shaped 12D blade can also be used interdentally with cutting edges on both sides of the blade. The 15C or 15‐blade can be used to make the releasing and crevicular incisions for debridement or flap design. To elevate flaps after initial incisions are made, the thin edge of a periosteal elevator can be introduced to lift the flap, including the periosteum, from the bone surface. Woodson, Pritchard, or Molt periosteal elevators come in varying sizes. Once the flap is elevated, straight chisels such as the Wedelstadt or Ochsenbein can be used with a push motion to help debride exposed surfaces.

Care of the delicate periodontal tissues can be enhanced by using less traumatic instruments such as DeBakey forceps, appropriately sized and sharpened scissors such as Goldman‐Fox no. 16, and needle‐holders, either regular types or the Castroviejo needle‐holder for precise techniques. The monofilament suture material, poligecaprone 25, is pliable, has low tissue drag, good knot security, ease of handling, and high initial tensile strength and strength‐to‐size ratio. For cutting through keratinized gingiva and mucosa, a reverse cutting needle is useful, while a taper‐cut needle can be used for more delicate tissue [35].

If electrosurgery or radiosurgery is used, whether for electrosection (incising, reverse bevel) or electrocoagulation, the tip should always be moving. Soft tissue diode lasers have been used for treatment of periodontal pockets, to help resect small areas of gingival enlargement or provide hemostasis when larger amounts of tissue need to be removed [36].

10.4.5 Treatment Planning

For any procedure to be moderately successful, deliberate planning with diagnostics, treatment steps, and reassessment are necessary. More advanced lesions require more planning, which can be a challenge in some veterinary practices where clients expect a “one‐stop shop” experience. Adequate communication is essential to determine if the client wants optimal therapy, which may include staged procedures and meticulous home care. Phase I

Before any advanced surgical periodontal therapy is selected, complete dental assessment and radiographs, scaling and root planning (SRP), and conservative management procedures should be done. A surgical attempt should only be performed if there is a lack of resolution in response to the SRP, as in human dentistry, after one to three months of oral hygiene. This first phase will identify those that have the potential of healing with conservative methods, but should also identify those clients that may be less willing to comply with the strict home care guidelines for optimal results. If a client is unwilling to return for regular care and provide home care, the tooth/teeth should be considered for possible extraction, if considered best for the patient’s health. Non‐surgical Periodontal Therapy

Non‐surgical periodontal therapy may be provided during the Phase I period for moderate cases or when return visits are unlikely. They may also be part of the Phase II procedures, particularly when inflamed areas improve after Phase I, but need additional treatment.

Considerations for non‐surgical treatment typically rely on the pocket depth encountered. In human patients, based on outcomes data, the critical probing depth (PD) of 5.4 mm has been used to determine whether or not to proceed to surgical intervention [37]. It was also confirmed that in a pocket of 4–6 mm, SRP resulted in better attachment gain than a surgical procedure [37].

The local delivery of antimicrobial products can be added to the SRP protocol to provide additional antibacterial effects directly at the site, while eliminating the need for patient compliance [38]. Fibers containing tetracycline (no longer available), microspheres that release minocycline (2%) and a 10% doxycycline gel are available as human products, with a similar doxycycline gel (8.5%) labeled for veterinary use. Some, not all, studies show a moderate reduction in pocket depth and gingival bleeding as compared to SRT alone [39]. These are to be used as an adjunct to SRP, not as a standalone treatment, and combining SDD with local antibiotic delivery after a thorough SRP has been shown to be significantly effective [40]. While the complete benefit may be somewhat debatable, since meticulous home care is unlikely in most veterinary patients, the potential benefit may be considered. Phase II

When the probing depth is greater than 5.4 or 6 mm, the decision for surgical intervention is likely to result in better clinical attachment than non‐surgical efforts [41]. This 5 mm standard, as adopted from human dentistry, closely corresponds to the extent that a 5 mm pocket, with bone level situated 2 mm apical to that, adds up to 7 mm of attachment loss in an average tooth length of 13 mm. With only half of the bony support remaining for this compromised human tooth, surgical intervention is often deemed necessary.

In the veterinary field, a 6 mm pocket can signify greater than 50% attachment loss (incisor or small premolar), making extraction the treatment of choice. In a large dog with a pocket on a canine tooth, this could only be considered Stage 2 periodontal disease attachment loss, but a surgical approach would still be needed for adequate access to the site. The variations in the tooth and root size that veterinarians experience is a reason why it is good to rely on the wealth of knowledge from the human dental field, but also to be able to apply the concepts according to the patient’s needs. This will also be addressed in concepts related to interdental tissue involvement.

This is why additional factors must be considered in surgical decisions beyond just the pocket depth [42, 43]. The full extent (amount and character) of bone loss and the root length will help determine the percentage of attachment loss or the tooth. Mobility of the tooth can play a significant role in deciding between treatment and extraction, as a lack of stability will decrease the chance of success. If the location of attachment loss is at a furcation, or between crowded teeth, the effectiveness of SRP may be questionable. Even the relative importance of the tooth and the probability of success (“restorability”) will factor into treatment choices. Beyond the tooth, the patient’s health status should be closely evaluated, due to the likely need for multiple anesthetic procedures. In addition, as stated previously, a dedicated owner will be essential for follow‐up care. Surgical Periodontal Therapy

The objectives of this surgical phase include eliminating pathological changes in the pocket wall to help maintain stable site(s) and to even regenerate periodontal tissues [43]. Surgical techniques first provide access to the area to be treated in order to reduce or eliminate pocket depth and to reshape tissues to help maintain periodontal health [43].

Reduction of pocket depth provides an area that is easier to keep clean and is less favorable to anaerobic bacterial proliferation. An active pocket with inflammation and bone loss can become inactive or quiescent with Phase I therapy, sometimes healing with a long junctional epithelial attachment [43]. While inactive pockets can be maintained with regular SRP and meticulous home care, creating a healthy sulcus (depth) surgically will provide better results.

Pocket depth is closely considered in treatment options: for example, SRP in pockets less than 2.9 mm (critical probing depth value) will induce loss of attachment, but result in a gain of attachment in deeper pockets [44]. The level of attachment in relation to the distance from the cementoenamel junction (CEJ) is even more important in considering the progression of the disease. Deeper pockets can be present in situations with gingival enlargement, with no attachment loss present.

Removal or resolution of the diseased pocket wall is the most common pocket therapy, whether SRP resolves the inflammation and shrinks the pocket depth or by employing surgical methods for removal or resection if needed. An apically repositioned flap with a resective technique will expose more root surface, but provides a pocket/sulcus depth that is easier to maintain. New attachment with regeneration of periodontal tissues is the ideal end result, though advanced techniques and materials are needed. In theory, extraction also treats the pocket by eliminating the tooth – or root.

Aesthetic considerations in human dentistry, particularly for the anterior dentition, are not as critical in veterinary patients, so greater detail can be given to maintaining function and comfort.

10.5 Treatment Considerations

10.5.1 Periodontal Surgical Principles

In order to provide the planned treatment, various principles should be followed, using appropriate techniques. Many techniques used in veterinary dentistry rely on experience in human dentistry, but specific differences must be kept in mind. For human patients, aesthetics in the rostral dentition is as important as function, so techniques such as papillary preservation may not be as critical in our patients. The distance in between teeth can also play a role in trying to extrapolate principles and techniques from the human field. Our goals should be to maximize the health and stability of functional teeth while maximizing our patients’ systemic health.

When starting these procedures, we should keep in mind that we are trying to provide access for the procedure, to reduce pocket depth either with resective or regenerative (additive) techniques and to reshape tissues for a more harmonious topography [43]. The critical zones to evaluate include the soft tissue pocket wall, the tooth surface, the underlying bone, and the attached gingiva [43].

In providing access, tissue either needs to be removed (gingivectomy) or displaced (flaps). Once accessed, the area in question is debrided of all irritants (plaque, calculus, diseased cementum, and soft tissue), treatment performed, and then the flap is closed. No matter what treatment is chosen, it has been shown that a certain pocket depth will recur, unless regenerative steps are taken. Therefore, the minimal goal for resective techniques (pocket reduction) will be to maintain the site without further loss of attachment [45]. One last scenario that will reduce the pocket depth is extraction; with complete removal of the tooth/teeth and pocket(s), the end stage of periodontal disease is accomplished.

10.5.2 Access by Displacement – Incisions

Displacement of a portion of the surrounding soft tissue is a common method of providing access to the depth of the periodontal pocket encountered. Using the parameters of the extent and nature of the pocket, the flap can be designed with keeping the final result – flap closure and pocket reduction – in mind. While adequate access is necessary, a gingival flap should be elevated only as far as is necessary for the approach. There will be a loss of at least 0.5 mm in bone thickness anywhere the periosteum is elevated off the bone surface, so a larger flap is not necessarily better. Mandibular first molars with pockets at the mesial and distal aspects may benefit from two separate flaps (often associated with adjacent tooth extractions) while leaving the interradicular region (furcation area) intact. Starting the coronal portion of the flap at full thickness and then transitioning to partial thickness (sharp dissection) can help preserve the apical portion of exposed bone [46].

Selecting the correct placement and type of incisions will allow you to both access the site and begin removal of affected tissues. Horizontal incisions are performed across the width of the defect to start tissue removal and facilitate flap displacement, and vertical incisions are made mesially and distally to the defect to provide release for flap displacement. It is important to use a new, sharp blade for delicate periodontal surgery. Do not use the same blade that may have been used to create flaps for surgical extractions in the same patient. Horizontal Incisions

Horizontal incisions following the tooth contour will be the internal (reverse) bevel and the crevicular (sulcular) incisions. The internal bevel, or first incision, is started a short distance from the gingival margin (depending on the character of the lesion) and is directed toward the alveolar crest (Figure 10.2). The scalpel blade is directed down toward the bone, following the scalloped contour of the teeth involved in the flap [48]. The second incision, the crevicular incision, is made from the base of the sulcus/pocket to the alveolar crest. These two incisions isolate a wedge‐shaped segment of tissue that is removed once the flap is elevated and the interdental (third) incision is made to separate the tissue from the bone in the interdental spaces, often with an Orban knife [46] (Figure 10.3).

Image described by caption and surrounding text.

Figure 10.2 Reverse bevel incision.

Source: Reprinted with permission from reference [47].

Image described by caption and surrounding text.

Figure 10.3 The three incisions necessary for flap surgery: (a) first (internal bevel) incision; (b) second (crevicular) incision; (c) third (interdental) incision.

Source: Illustration by Josephine Banyard, DVM, DAVDC, adapted from reference [46].

A conservative approach for papilla management (interseptal or interdental incisions) includes incising the tissue between the contact point of the two adjacent teeth, with reflection of the buccal and lingual mucosa [44]. This approach is often done for flaps that will be displaced upon closure (apically, laterally repositioned). Papillary preservation can be performed if there is sufficient interdental space and if the flap will be non‐displaced (closed into its original location). With this, the base of the papilla remains with one of the flaps (buccal or lingual) and is replaced into the interdental space at closure. With interdental lesions, this method is preferred (especially in anterior teeth in humans), because it protects the interdental area more effectively [43]. This can extrapolated to the incisors in dogs, but may not be as crucial in the other regions while sacrificing juxtaposed teeth (e.g., for treatment of the mandibular first molar).

The papillary preservation technique (PPT) uses sulcular incisions with a semi‐lunar incision that dips apically (at least 5 mm from the gingival margin) lingual/palatal to the papillary tissue with full thickness elevation. This keeps the papilla intact with the buccal flap, and is replaced and sutured after treatment is complete. The modified PPT (MPPT) moves the horizontal incision apical to the papilla at the buccal aspect, with an initial horizontal internal crossed mattress suture to relieve tension on tissue closure. A second incision (vertical internal mattress suture) is used for primary closure [49]. A simple papillary preservation technique (SPPT) is used for narrow interdental spaces and extends from the buccal line angle of the affected tooth to the midinterproximal portion of the papilla under the contact point [50].

In many veterinary cases (in the authors’ experiences), this papillary tissue is well‐defined only with healthy tissue where the teeth are closely positioned – at the incisor areas and at the fourth premolars through molar regions. Demonstrating this in cadaver specimens is possible, but once there is a need of periodontal surgery, this tissue is often so damaged that the PPT is of little value.

Incisions in the palatal mucosa are handled differently from buccal or lingual incisions. With keratinized tissue that is all attached, release and repositioning is typically not possible. The primary goal is to create a thin flap that will be replaced at the root–bone region. An internal bevel incision may be adequate or a horizontal incision followed by an internal bevel can be used for internal gingivectomy [51]. Vertical Incisions – Releasing Incisions

Vertical incisions are made to provide additional release of a flap, as far as is needed for conservative therapy, or past the mucogingival line for release of the flap and full displacement, particularly if the flap is to be repositioned. These vertical incisions should be made at a line angle on an adjacent tooth mesial or distal to the area being treated [52]. The term line angle is defined as dividing lines formed at the junction of two of the tooth’s surfaces (e.g., mesiobuccal) (Figure 10.4). Determining the angle can be challenging at times, but the designation is meant to avoid making incisions in areas that would be detrimental to the treatment. By a process of elimination, a close interdental incision would not be chosen, as this would damage the papilla and result in closure in an area difficult to clean. Radicular incisions, at the midpoint of the root, would result in too much tension and difficulty in closure. Interradicular incisions can be made but the furcation area is generally avoided.

Image described by caption.

Figure 10.4 Line angles. Line angles incisions (a) and interradicular incisions (b) are considered appropriate for releasing incisions, while radicular midface incisions (c) and interproximal incisions (d) are not considered appropriate.

Source: Illustration by Josephine Banyard, DVM, DAVDC, adapted from First Edition.

If there is sufficient space (diastema) between the tooth to be treated and the nearest tooth, then the incision can be made just beyond the treatment site, into healthy gingiva of the interdental area [52]. Frequently the site to be treated would benefit from extraction of an adjacent, less strategic tooth. The releasing incision can be made at the extent of the extracted tooth furthest from the treated tooth for optimal access. Common areas that benefit from these selective extractions are the mandibular third incisor extracted to treat mandibular canine; the mandibular first molar treated with extraction of either the fourth premolar or second molar; and the maxillary fourth premolar with the third premolar extracted. Particularly if the defect is interdental to these teeth, extraction of the one allows much better access to treat the other, adequate closure, and minimizing the challenges of keeping the crowded area clean.

In interdental areas with significantly inflamed tissue, an interdental denudation procedure may be beneficial. By removing the papilla and adjacent diseased tissues, this area can be left to heal by secondary intention and often responds well [46]. It cannot be used in areas where a bone graft has been placed.

10.5.3 Access by Displacement – Flaps

Using the incisions just described, there are three categories of flaps, selected depending on the pocket depth and the location of the MGJ. Modified Widman Flap

For access of a root surface for scaling and root planing, and to eliminate the pocket lining, the modified Widman flap is used. Its primary goal is not for pocket reduction, though the pocket depth may decrease as the tissues heal [51]. The internal beveled incision will follow the scalloped outline of the gingiva, 1–2 mm from the margin and teeth, down to the alveolar crest. Vertical releasing incisions are generally not done and an attempt can be made to maintain the thickness of the interdental papilla [51]. The gingiva is reflected and the second (crevicular) incision is made to the apical extent of the pocket epithelium. The third incision horizontal is made in order to remove the supracrestal pocket tissue (not into any deeper pockets). This provides access and visualization for root debridement. Interdental or periodontal sling sutures are placed to keep the trimmed tissue close to the tooth surface [43, 53]. Undisplaced Flap

An undisplaced flap will provide access and help to remove the pocket wall, excising the diseased gingiva, and can be considered an internal bevel gingivectomy. Sufficient attached gingiva must be present once the pocket wall is removed. After marking the depth of the pockets, an internal bevel incision is made to a point apical to the alveolar crest, depending on the thickness of the tissue, if there is enough attached gingiva. If there is less attached gingiva, this internal bevel incision may need to be directed to the alveolar crest instead. This initial incision should attempt to remove as much of the excess thickness of the flap as possible, both buccally and palatally. Once the crevicular and interdental incisions are made, the excess tissue is removed and the pocket debrided (SRP). Vertical releasing incisions are typically not needed. The final flap edge should rest on the root–bone junction, if the incisions are properly planned. If not, the flap edge can be recontoured (if too long) or the bone contoured (if too short). A continuous sling suture (described later) holds the flap edges in place [51]. Apically Repositioned Flap

If there is limited attached gingiva, and a portion or all of the attached gingiva is overexposed root, not bone, then an apically repositioned flap will allow this band of gingiva to be placed over the tooth–bone junction. The initial internal bevel incision is made close to the gingival margin, directed to the crest of the bone [51]. After this is elevated, the crevicular incision is made, followed by interdental incisions and debridement. Vertical incisions are made past the MGJ and the full‐ or split‐thickness flaps are elevated (Figure 10.5). Thorough SRP and osseous recontouring is done prior to closure of the flap in a more apical position (Figure 10.6). Movement of the attached gingiva to a position over the alveolar bone will expose the root(s), but will help reduce the periodontal pocket by transforming the previously unattached keratinized gingiva into attached tissue [51].

Image described by caption.

Figure 10.5 Diagram showing elevation of full‐thickness mucogingival flap to expose several millimeters of bone. The flap is transitioned to a partial thickness flap apically.

Source: Reprinted with permission from reference [47].

Image described by caption.

Figure 10.6 Diagram showing alveolar bone contouring and removal of sharp bone edges to remove all diseased tissues before flap is replaced apically.

Source: Reprinted with permission from reference [47]. Coronally Advanced Flap

In areas of gingival recession, a displaced flap can be repositioned coronally to cover the exposed root. Issues in human dentistry with GR include aesthetics, root hypersensitivity, and challenges in plaque control [54]. The most predictable results in treating minor GR defect (Miller Class I and II) traditionally rely on a coronally advanced flap (CAF) with root conditioning, sometimes the use of a enamel matrix derivative (EMD – discussed later in the chapter), and often with the placement of a connective tissue graft (CTG) [55, 56]. In dog model studies of Class I GR defects, the addition of CTG or collagen membranes (CMs) did not have a significant advantage over CAF alone [57].

While a CAF may be effective in covering the defect, unless EMD products are used, fibroblasts may repopulate more quickly than PDL cells, so the healing will be only a new attachment, with a chance of resorption [55]. The CTG can be harvested from a distal wedge incision or a palatal donor site. Even if complete root coverage (CRC) is obtained, often the flap tissue remains fairly thin, a risk factor for future recession. A modified microsurgical tunnel technique has been described, using tunneling knives that undermine the buccal gingiva (split‐thickness), creating a continuous tunnel. A CTG inserted into the tunnels appears to result in thicker gingiva (0.8 mm for critical flap thickness) and improved clinical outcomes [56]. These delicate flaps require meticulous home hygiene and avoidance of any trauma, including lingual trauma, to the healing graft, which is typically unrealistic in most canine veterinary patients. Determining the relative impact of a shallow gingival recession defect in a veterinary patient should be evaluated when contemplating advanced procedures and considering oral hygiene levels. Lateral Pedicle Sliding Flap (LPSF)

Lateral pedicle sliding flaps (LPSFs) utilize grafting healthy periodontal tissue from a site adjacent to an area of gingival recession or fenestration. Details of the procedure will be covered later in the chapter. Any flap should have a wide base with sufficient harvested tissue to cover 1.5 times the width of the defect itself. Again, the risk to the clinical outcome‐to‐benefit ratio should be determined for any individual patient. Free Gingival Graft

Free gingival grafts (FGG) have been used since the 1960s initially to provide gingival extension, replacing alveolar mucosa with an autogenous graft apical to the area of a thin attached gingival height. It can also be used to cover an exposed root surface and to increase the width and thickness of attached gingiva [58]. Though relatively easy to perform, with a high predictability in human patients, there are issues with acquiring a donor site of sufficient size and leaving the donor site open to heal by second intention [59]. A difference in the color of the donor tissue can impair aesthetics, as well as a mismatch in the gingival width and alignment of the MGJ [58]. Variations of the procedure include developing a gingival unit graft, including marginal and papillary portions (from palatal aspect of molars), with better vasculature potential [58]. In a partially epithelialized FGG, the apical portion of graft (that would lie apical to the MGJ) is de‐epithelialized, to avoid the appearance of a mismatch of the MGJ between donor and recipient tissue. A graft can also be crafted to keep an epithelized “island” of the graft that corresponds to the defect, with the remaining de‐epithelized portion of the graft placed on top of the surrounding connective tissue in a tunneling technique [58]. Once more, the risk‐to‐benefit ratio, including consideration for the level of oral hygiene, should be considered before performing advanced procedures on veterinary patients. Replacement material, such as an acellular dermal allograft (ADM – discussed later in chapter) may not provide quite as much coverage, but can be an alternative to free graft techniques [59]. Crescent Flap

Specific flaps can be developed to manage individual teeth, such as using a crescent shaped flap to access a deep pocket on the palatal aspect of maxillary canine teeth. The initial incision extends mesially from the mesial aspect of the canine tooth, then arcs into the palatal mucosa, to provide a flap that exposes the mesial and palatal aspect of the root once elevated. This flap can incorporate the palatal artery into its base, with ligation at the rostral aspect. Once the pocket is treated, slight debridement of the leading edge of the flap can bring the tissue into close approximation with the tooth, to keep the underlying regenerative material in place. A slight gap may be present at the crescent incision site at the palatal aspect, but this will heal by second intention. Alternatively, releasing incisions at the distal and mesial aspects of the tooth can be made. Oblique Incision

An oblique incision can be made from the gingival margin of a mandibular canine to allow for collar expansion of the attached gingiva when sutured [60]. This is primarily performed for crown lengthening during prosthodontic treatment, but can also be used for apically repositioned flap techniques on the tooth.

10.5.4 Access by Removal – Gingivectomy/Gingivoplasty

If a pseudopocket is formed by gingival enlargement, simple reduction of the excess tissue (gingivectomy) removes the pocket wall and provides access for scaling and root planing [61]. Keratinized tissue will be removed from the external surface using a beveled incision, preserving at least 3 mm of attached gingiva. This can also be used to reduce suprabony pockets and areas of suprabony abscessation. If the pocket depth is apical to the MGJ, or if osseous recontouring is needed, then a flap technique should be employed.

Gingivoplasty refers to the reshaping of the gingiva in the absence of pockets. Small areas of gingival enlargement, clefts, and craters can be recontoured to restore the gingival margins to a healthier state. Scalpel blades, periodontal knives, diamond stones or 12‐fluted burs can be used for this procedure.

Details of these procedures, including wedge resection and crevicular debridement, will be discussed later in this chapter.

10.5.5 Debridement of Irritants

A main objective in surgical periodontal therapy is to provide access to remove all irritants – plaque, calculus, diseased cementum, bone, and soft tissue – from the area to be treated. The basics of closed root planing and subgingival (gingival) curettage were described in Chapter 5 – Periodontology. Further definition separates gingival curettage (removal of the inflamed soft tissue lateral to the pocket wall and the JE) as compared to subgingival curettage that is performed apical to the JE (which is seldom indicated) [61]. The excisional new attachment procedure (ENAP) is definitive subgingival curettage performed with a knife, making an internal bevel incision from the free gingival margin to a point just apical to the bottom of the pocket (Takei CP 577). The excised tissue is removed with curettes and sutures placed if needed. In most human patients, it has been shown that with a thorough SRP, most of the bacteria is eliminated, and the granulation tissue present is slowly resorbed [61].

Removing the chronic granulation tissue and diseased or scarred epithelial lining is essential in flap surgery for better access to underlying surfaces. It is an important step when attempting to encourage new attachment or if aggressive surgical techniques cannot be used to help reduce inflammation. Ultrasonic curettage has been shown to be effective in debriding the epithelial lining of periodontal pockets. Chemical debridement (decontamination) has been proposed [62], but with concerns over a lack of controlled effect, additional tissue destruction may occur.

The concept of root conditioning – demineralizing the scaled root surface to expose collagen fibers to enhance the repopulation of periodontal cells – has been demonstrated in vitro. However, studies are lacking to show any benefit of root conditioning on periodontal surgery outcomes (discussed later in the chapter).

10.5.6 Flap Closure

When a flap is closely adapted to the alveolar process at the tooth/bone junction. there will be minimal inflammatory response, and the space in which the blood clot was formed (present within 24 hours after surgery) gets thinner within one to three days [46]. Gingiva and mucosa heal more rapidly than skin, so the minimal coaptation time is about five days [63].

Suturing techniques will vary according to the function of the closure (extraction versus membrane or flap placement). A simple interrupted pattern is used frequently, with the suture material placed at 2–3 mm from the gingival margin or papilla. In human dentistry, an interrupted pattern is used, with the suture passed from the epithelium to connective tissue on the buccal aspect, and again from the epithelium to connective tissue on the lingual/palatal tissue. This results in good apposition of the two portions of the flap, but the suture material will be in contact with the incision line itself, so should not be used if primary adaptation is needed. A horizontal mattress can be placed to distribute the tension of the suture, either in an external or internal pattern. The internal pattern will result in a smaller amount of external suture material buccally and labially/palatally, but some incision edge eversion may be possible. A further modification carries the needle back through the loop, bringing that portion externally by securing it during the knot placement [65]. The external pattern can have either crossed (cruciate) or parallel suture material resting on top of the interdental tissue [66]. A vertical internal mattress has the suture holes placed 2 and 3 mm from the papilla, with both inversion and eversion to keep the papilla more upright [66].

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Aug 15, 2020 | Posted by in GENERAL | Comments Off on Oral Surgery – Periodontal Surgery

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