Veterinary Dentistry Dentisterie vétérinaire Periodontology: An overview of alveolar bone expansion Jérôme D’Astous
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ith chronic infection involving osseous tissue, there is bone remodeling which involves bone destruction and also bone formation. Bone formation will sometimes be extensive and may result in a hard mass of osseous tissue. In periodontal disease, areas of bone formation are found immediately adjacent to sites of active bone resorption and also along trabecular surfaces at a distance from the inflammation in an apparent effort to reinforce the remaining bone (i.e., buttressing bone formation) (1). When buttressing occurs on the external surface of the alveolar bone, it may cause bulging (1). This thickening of the alveolar bone is known as alveolar bone expansion (ABE) or alveolar osteitis (2). The alveolar margin will gradually expand, usually on the buccal aspect of the tooth, and a hard gingival enlargement can be seen clinically. This should not be confused with a different condition in humans also called alveolar osteitis, or dry socket, which represents a painful delayed healing of an
extraction and which is not associated with infection (3). Cats are more frequently seen with ABE than dogs; although this condition can develop in any tooth, it is most commonly found in canine teeth. Alveolar bone expansion will not result at every site of periodontal disease and the underlying processes resulting in ABE are unknown (4).
Figure 1. Photograph of an 8-year-old, neutered, male domestic cat presented for its first complete professional dental consultation. The patient had no concomitant disease and complete blood analyses were within normal limits. All canine teeth showed severe gingivitis with purulent sulcular discharge, mild gingival recession or extrusion, various degrees of attachment loss on probing, and alveolar bone expansion (ABE). The following figures show treatment of this patient and follow-up photographs of these teeth.
Figure 2. Oblique intraoral dental radiograph of the maxillary right canine (104). There was deep probing on the palatal aspect of this tooth and about 50% attachment loss radiographically (black arrowheads). Alveolar bone expansion (ABE) was large, mainly bucco-distally, with a mottled appearance on radiograph (white arrowheads). A draining tract was also present buccodistally on the gingiva. Surgical extraction was performed.
Centre Vétérinaire D.M.V., 2300 54e Avenue, Lachine, Québec H8T 3R2. Address all correspondence to Dr. Jérôme D’Astous; e-mail: [email protected] Use of this article is limited to a single copy for personal study. Anyone interested in obtaining reprints should contact the CVMA office ([email protected]) for additional copies or permission to use this material elsewhere. CVJ / VOL 56 / MARCH 2015
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Figure 3. Intraoral dental radiographs of the rostral mandible. Preoperative (A), immediately postoperative (B), 9 months postoperative (C), and 28 mo postoperative (D) radiographs are shown. The right canine (404) was extracted because of a deep lingual periodontal pocket (black arrowheads). The left canine (304) showed more ABE labially than tooth 404 (white arrowhead) but no attachment loss lingually. Tooth 304 was treated with an apically repositioned flap and bone contouring (resective surgery). Note the reestablishment of a normal topography of the alveolar margin labially with a tapered margin. Follow-up radiographs showed that more remodelling occurred resulting in an even smoother knife-edge alveolar margin. Extraction of the second and third left incisors (302, 303) was done initially to facilitate periodontal surgery on 304. The retained root of the first right incisor (401) and the second right incisor (402; root fracture) were also extracted at 28 mo after the initial surgery. 296
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Figure 4. Photographs of tooth 304 preoperative (A), immediately postoperative (B), 9 mo postoperative (C), and 28 mo postoperative (D). Mild gingivitis persisted on this tooth at 9 mo but there was no periodontal pocket on probing (initially 3 mm mesially and labially); gingiva was healthy at 28 mo after surgery. This patient received amoxicillin/clavulanic acid initially for 2 wk after surgery. The owner did not follow homecare instructions of daily tooth brushing, starting 4 wk after the surgery, which could have compromised the success of the procedure. Complete professional dental care including scaling and polishing was performed at 9 and 28 mo after surgery.
Diagnosis During oral examination, in addition to the thickening of the alveolar bone and gingiva, signs of periodontal disease that will usually be present include gingivitis, gingival recession, periodontal pocket detected by probing, and/or tooth mobility (Figure 1). Generally, the larger the ABE, the more advanced is the periodontal disease. Abnormal tooth extrusion (or supereruption) may also be noted. On intra-oral dental radiograph, the alveolar margin will appear thickened and more radiolucent. Large lesions may have a mottled appearance, mimicking rough and large trabeculae (Figure 2). Vertical alveolar bone loss is usually present with a widening of the adjacent periodontal ligament space. The bony defect is frequently apical to the alveolar margin, thus forming an infrabony pocket (Figure 3). In a study looking at the radiographic pattern of periodontitis in cats, the authors found that 53% of cats had expansion of the buccal alveolar bone (. 1 mm) at 1 or more canine teeth (4). Mild buccal bone expansion (1 to 2 mm) was seen with several patterns of bone loss or in cats with normal alveolar bone height. Moderate and severe cases (. 2 mm) were almost always associated with severe CVJ / VOL 56 / MARCH 2015
vertical bone loss. Mild ABE may develop with chronic gingival inflammation before attachment loss. Some cats with ABE and severe periodontitis may present with oral pain, ptyalism, and an inability to completely close the mouth. This happens when a severely infected tooth is luxated or displaced and prevents complete occlusion due to contact with dental structures in the opposite arcade. This situation is occasionally confused with a temporo-mandibular luxation and/or caudal mandibular fracture. Severe periodontal disease of the maxillary canine teeth may also result in oro-nasal communication and nasal discharge. Alveolar bone expansion is typically associated with chronic periodontal disease but other conditions may cause expansion of the alveolar bone (e.g., osteolytic/ osteoproliferative disease such as a malignant tumor, the most frequent in cats being a squamous cell carcinoma). If necessary, a biopsy should be harvested for histological differentiation.
Treatments Most cases of ABE are detected late with advanced periodontal disease and the only treatment option is exodontia (2, Figure 2). Even if many teeth with severe periodontitis and ABE can be 297
DE NTI STE R I E VÉTÉR I NAI R E
Figure 5. Oblique intraoral dental radiographs of the left maxillary canine (204). Preoperative (A), immediately postoperative (B), 9 mo postoperative (C), and 28 mo postoperative (D) radiographs are shown. Alveolar bone expansion (ABE) was mild (white arrowheads) and present only distally with a 3 mm periodontal pocket. This tooth was treated in the same way as tooth 304 (Figure 4) with similar results.
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Figure 6. Preoperative (A), immediately postoperative (B), 9 mo postoperative (C), and 28 mo postoperative (D) photos of tooth 204.
extracted non-surgically, it is recommended to close the alveolus with sutures to prevent postoperative infection or delayed healing (5). A full-thickness mucoperiosteal flap is often necessary; however, it is more difficult to elevate such a flap over ABE because of the thickened gingival tissue that is attached firmly to the underlying bone or to the thick pocket lining. Once the ABE is exposed, it can be reduced and smoothed to help proper and tension-free closure; the alveolus should also be debrided of diseased epithelium at this time (5). For maxillary canine tooth extractions in cats with ABE, bone should be removed only as needed in order to minimize the risk of maxillary lip entrapment by the mandibular canine tooth postoperatively. Releasing the periosteum is helpful to mobilize the flap. Remodelling of ABE after extraction is usually minimal and it is common to see persistent bulged bone after surgery. If the diagnosis is made before the disease becomes too advanced, other treatment options can be considered. For suprabony periodontal pocket, ABE is minimal and careful scaling and root planing (SRP) is the treatment of choice. Root planing is mostly performed with a combination of hand and ultrasonic instrumentation. An ultrasonic scaling device should be used subgingivally with proper settings and specific subgingival tips. Compared to hand instruments, ultrasonic scalers appear to have an additional bactericidal effect from cavitational CVJ / VOL 56 / MARCH 2015
activity and acoustic microstreaming (1). The periodontal condition should then be maintained with home oral hygiene (e.g., everyday tooth brushing) and regular professional dental care. With ABE, most periodontal pockets will be infrabony. The morphology of the infrabony defect is evaluated with careful probing, intraoral dental radiographs, and eventually surgical exposure of the areas. Knowing the morphology of the defect (i.e., the number of adjacent osseous walls) is important to determine proper treatment and prognosis. For mild ABE and infrabony defects, advanced periodontal surgery (resective or reconstructive) should be considered in addition to SRP to recover normal periodontal topography. Resective surgery usually consists of the following steps: i) a full-thickness mucoperiosteal flap is created to expose the defect; ii) the root surface is scaled and gentle root planing is performed; iii) the defect is debrided, removing all granulation tissue; iv) alveoloplasty is performed to resect the infrabony pocket and to contour the alveolar bone with a physiological tapered margin; v) the flap is finally apposed apically compared to its original position (Figures 3 to 6). Reconstructive surgery involves bone grafting, guided tissue regeneration using membranes, or a combination of both. The osseous defect is not removed but treated to regenerate bone and new attachment, ideally creating a new periodontium. With proper case selection, these treatments have 299
DE NTI STE R I E VÉTÉR I NAI R E
a very good prognosis; however, they are very technique-sensitive and should only be performed by a veterinary dental specialist. Home oral hygiene and regular professional dental care are also very important following periodontal surgery (periodontal maintenance).
Conclusion Alveolar bone expansion is common and is easily diagnosed with meticulous oral examination and intraoral dental radiographs. It usually develops with chronic periodontal disease and could thus be prevented with home oral hygiene and regular professional dental care. Early diagnosis is important as more therapeutic options are then available, other than exodontia. Veterinarians are encouraged to do more frequent oral examinations under sedation or anesthesia to allow probing and intraoral dental radiographs. This kind of examination should not only be done when there is obvious need for scaling, as periodontitis will often start before this point or be undetected during conscious
300
oral examination. A complete oral examination is mandatory to evaluate treatment options but other factors should also influence decision-making (e.g., owner compliance with homecare and future professional dental care). It is recommended that you consult with a veterinary dental specialist when considering advanced periodontal surgery for one of your patients.
References 1. Newman MG, Takei HH, Klokkevold PR, Carranza FA. Carranza’s Clinical Periodontology. 12th ed. St. Louis, Missouri: Saunders, 2015: 875 p. 2. Beebe DE, Gengler WR. Osseous surgery to augment treatment of chronic periodontitis of canine teeth in a cat. J Vet Dent 2007;24:30–38. 3. Hupp JR, Tucker MR, Ellis E. Contemporary Oral and Maxillofacial Surgery. 5th ed. St. Louis, Missouri: Mosby Elsevier, 2008:714 p. 4. Lommer MJ, Verstraete FJ. Radiographic patterns of periodontitis in cats: 147 cases (1998–1999). J Am Vet Med Assoc 2001;218:230–234. 5. Verstraete FJM, Lommer MJ. Oral and Maxillofacial Surgery in Dogs and Cats. New York, New York: Saunders, 2012:1.
CVJ / VOL 56 / MARCH 2015
W
ith chronic infection involving osseous tissue, there is bone remodeling which involves bone destruction and also bone formation. Bone formation will sometimes be extensive and may result in a hard mass of osseous tissue. In periodontal disease, areas of bone formation are found immediately adjacent to sites of active bone resorption and also along trabecular surfaces at a distance from the inflammation in an apparent effort to reinforce the remaining bone (i.e., buttressing bone formation) (1). When buttressing occurs on the external surface of the alveolar bone, it may cause bulging (1). This thickening of the alveolar bone is known as alveolar bone expansion (ABE) or alveolar osteitis (2). The alveolar margin will gradually expand, usually on the buccal aspect of the tooth, and a hard gingival enlargement can be seen clinically. This should not be confused with a different condition in humans also called alveolar osteitis, or dry socket, which represents a painful delayed healing of an
extraction and which is not associated with infection (3). Cats are more frequently seen with ABE than dogs; although this condition can develop in any tooth, it is most commonly found in canine teeth. Alveolar bone expansion will not result at every site of periodontal disease and the underlying processes resulting in ABE are unknown (4).
Figure 1. Photograph of an 8-year-old, neutered, male domestic cat presented for its first complete professional dental consultation. The patient had no concomitant disease and complete blood analyses were within normal limits. All canine teeth showed severe gingivitis with purulent sulcular discharge, mild gingival recession or extrusion, various degrees of attachment loss on probing, and alveolar bone expansion (ABE). The following figures show treatment of this patient and follow-up photographs of these teeth.
Figure 2. Oblique intraoral dental radiograph of the maxillary right canine (104). There was deep probing on the palatal aspect of this tooth and about 50% attachment loss radiographically (black arrowheads). Alveolar bone expansion (ABE) was large, mainly bucco-distally, with a mottled appearance on radiograph (white arrowheads). A draining tract was also present buccodistally on the gingiva. Surgical extraction was performed.
Centre Vétérinaire D.M.V., 2300 54e Avenue, Lachine, Québec H8T 3R2. Address all correspondence to Dr. Jérôme D’Astous; e-mail: [email protected] Use of this article is limited to a single copy for personal study. Anyone interested in obtaining reprints should contact the CVMA office ([email protected]) for additional copies or permission to use this material elsewhere. CVJ / VOL 56 / MARCH 2015
295
DE NTI STE R I E VÉTÉR I NAI R E
Figure 3. Intraoral dental radiographs of the rostral mandible. Preoperative (A), immediately postoperative (B), 9 months postoperative (C), and 28 mo postoperative (D) radiographs are shown. The right canine (404) was extracted because of a deep lingual periodontal pocket (black arrowheads). The left canine (304) showed more ABE labially than tooth 404 (white arrowhead) but no attachment loss lingually. Tooth 304 was treated with an apically repositioned flap and bone contouring (resective surgery). Note the reestablishment of a normal topography of the alveolar margin labially with a tapered margin. Follow-up radiographs showed that more remodelling occurred resulting in an even smoother knife-edge alveolar margin. Extraction of the second and third left incisors (302, 303) was done initially to facilitate periodontal surgery on 304. The retained root of the first right incisor (401) and the second right incisor (402; root fracture) were also extracted at 28 mo after the initial surgery. 296
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Figure 4. Photographs of tooth 304 preoperative (A), immediately postoperative (B), 9 mo postoperative (C), and 28 mo postoperative (D). Mild gingivitis persisted on this tooth at 9 mo but there was no periodontal pocket on probing (initially 3 mm mesially and labially); gingiva was healthy at 28 mo after surgery. This patient received amoxicillin/clavulanic acid initially for 2 wk after surgery. The owner did not follow homecare instructions of daily tooth brushing, starting 4 wk after the surgery, which could have compromised the success of the procedure. Complete professional dental care including scaling and polishing was performed at 9 and 28 mo after surgery.
Diagnosis During oral examination, in addition to the thickening of the alveolar bone and gingiva, signs of periodontal disease that will usually be present include gingivitis, gingival recession, periodontal pocket detected by probing, and/or tooth mobility (Figure 1). Generally, the larger the ABE, the more advanced is the periodontal disease. Abnormal tooth extrusion (or supereruption) may also be noted. On intra-oral dental radiograph, the alveolar margin will appear thickened and more radiolucent. Large lesions may have a mottled appearance, mimicking rough and large trabeculae (Figure 2). Vertical alveolar bone loss is usually present with a widening of the adjacent periodontal ligament space. The bony defect is frequently apical to the alveolar margin, thus forming an infrabony pocket (Figure 3). In a study looking at the radiographic pattern of periodontitis in cats, the authors found that 53% of cats had expansion of the buccal alveolar bone (. 1 mm) at 1 or more canine teeth (4). Mild buccal bone expansion (1 to 2 mm) was seen with several patterns of bone loss or in cats with normal alveolar bone height. Moderate and severe cases (. 2 mm) were almost always associated with severe CVJ / VOL 56 / MARCH 2015
vertical bone loss. Mild ABE may develop with chronic gingival inflammation before attachment loss. Some cats with ABE and severe periodontitis may present with oral pain, ptyalism, and an inability to completely close the mouth. This happens when a severely infected tooth is luxated or displaced and prevents complete occlusion due to contact with dental structures in the opposite arcade. This situation is occasionally confused with a temporo-mandibular luxation and/or caudal mandibular fracture. Severe periodontal disease of the maxillary canine teeth may also result in oro-nasal communication and nasal discharge. Alveolar bone expansion is typically associated with chronic periodontal disease but other conditions may cause expansion of the alveolar bone (e.g., osteolytic/ osteoproliferative disease such as a malignant tumor, the most frequent in cats being a squamous cell carcinoma). If necessary, a biopsy should be harvested for histological differentiation.
Treatments Most cases of ABE are detected late with advanced periodontal disease and the only treatment option is exodontia (2, Figure 2). Even if many teeth with severe periodontitis and ABE can be 297
DE NTI STE R I E VÉTÉR I NAI R E
Figure 5. Oblique intraoral dental radiographs of the left maxillary canine (204). Preoperative (A), immediately postoperative (B), 9 mo postoperative (C), and 28 mo postoperative (D) radiographs are shown. Alveolar bone expansion (ABE) was mild (white arrowheads) and present only distally with a 3 mm periodontal pocket. This tooth was treated in the same way as tooth 304 (Figure 4) with similar results.
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Figure 6. Preoperative (A), immediately postoperative (B), 9 mo postoperative (C), and 28 mo postoperative (D) photos of tooth 204.
extracted non-surgically, it is recommended to close the alveolus with sutures to prevent postoperative infection or delayed healing (5). A full-thickness mucoperiosteal flap is often necessary; however, it is more difficult to elevate such a flap over ABE because of the thickened gingival tissue that is attached firmly to the underlying bone or to the thick pocket lining. Once the ABE is exposed, it can be reduced and smoothed to help proper and tension-free closure; the alveolus should also be debrided of diseased epithelium at this time (5). For maxillary canine tooth extractions in cats with ABE, bone should be removed only as needed in order to minimize the risk of maxillary lip entrapment by the mandibular canine tooth postoperatively. Releasing the periosteum is helpful to mobilize the flap. Remodelling of ABE after extraction is usually minimal and it is common to see persistent bulged bone after surgery. If the diagnosis is made before the disease becomes too advanced, other treatment options can be considered. For suprabony periodontal pocket, ABE is minimal and careful scaling and root planing (SRP) is the treatment of choice. Root planing is mostly performed with a combination of hand and ultrasonic instrumentation. An ultrasonic scaling device should be used subgingivally with proper settings and specific subgingival tips. Compared to hand instruments, ultrasonic scalers appear to have an additional bactericidal effect from cavitational CVJ / VOL 56 / MARCH 2015
activity and acoustic microstreaming (1). The periodontal condition should then be maintained with home oral hygiene (e.g., everyday tooth brushing) and regular professional dental care. With ABE, most periodontal pockets will be infrabony. The morphology of the infrabony defect is evaluated with careful probing, intraoral dental radiographs, and eventually surgical exposure of the areas. Knowing the morphology of the defect (i.e., the number of adjacent osseous walls) is important to determine proper treatment and prognosis. For mild ABE and infrabony defects, advanced periodontal surgery (resective or reconstructive) should be considered in addition to SRP to recover normal periodontal topography. Resective surgery usually consists of the following steps: i) a full-thickness mucoperiosteal flap is created to expose the defect; ii) the root surface is scaled and gentle root planing is performed; iii) the defect is debrided, removing all granulation tissue; iv) alveoloplasty is performed to resect the infrabony pocket and to contour the alveolar bone with a physiological tapered margin; v) the flap is finally apposed apically compared to its original position (Figures 3 to 6). Reconstructive surgery involves bone grafting, guided tissue regeneration using membranes, or a combination of both. The osseous defect is not removed but treated to regenerate bone and new attachment, ideally creating a new periodontium. With proper case selection, these treatments have 299
DE NTI STE R I E VÉTÉR I NAI R E
a very good prognosis; however, they are very technique-sensitive and should only be performed by a veterinary dental specialist. Home oral hygiene and regular professional dental care are also very important following periodontal surgery (periodontal maintenance).
Conclusion Alveolar bone expansion is common and is easily diagnosed with meticulous oral examination and intraoral dental radiographs. It usually develops with chronic periodontal disease and could thus be prevented with home oral hygiene and regular professional dental care. Early diagnosis is important as more therapeutic options are then available, other than exodontia. Veterinarians are encouraged to do more frequent oral examinations under sedation or anesthesia to allow probing and intraoral dental radiographs. This kind of examination should not only be done when there is obvious need for scaling, as periodontitis will often start before this point or be undetected during conscious
300
oral examination. A complete oral examination is mandatory to evaluate treatment options but other factors should also influence decision-making (e.g., owner compliance with homecare and future professional dental care). It is recommended that you consult with a veterinary dental specialist when considering advanced periodontal surgery for one of your patients.
References 1. Newman MG, Takei HH, Klokkevold PR, Carranza FA. Carranza’s Clinical Periodontology. 12th ed. St. Louis, Missouri: Saunders, 2015: 875 p. 2. Beebe DE, Gengler WR. Osseous surgery to augment treatment of chronic periodontitis of canine teeth in a cat. J Vet Dent 2007;24:30–38. 3. Hupp JR, Tucker MR, Ellis E. Contemporary Oral and Maxillofacial Surgery. 5th ed. St. Louis, Missouri: Mosby Elsevier, 2008:714 p. 4. Lommer MJ, Verstraete FJ. Radiographic patterns of periodontitis in cats: 147 cases (1998–1999). J Am Vet Med Assoc 2001;218:230–234. 5. Verstraete FJM, Lommer MJ. Oral and Maxillofacial Surgery in Dogs and Cats. New York, New York: Saunders, 2012:1.
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