Feline chronic gingivostomatitis is characterized by chronic, severe inflammation of the gingiva, buccal mucosa, and caudal aspect of the oral mucosa; the palate, oropharynx, and tongue are also occasionally involved.1,2 Presence of caudal stomatitis (also called caudal mucositis; often incorrectly referred to as faucitis) differentiates FCGS from other inflammatory oral mucosal diseases.2 Hyperglobulinemia is reported in up to 50% of cases.3,4 Other clinical signs such as inappetence, weight loss,5,6 and unkempt hair7 may also be present, particularly at more advanced stages.
Feline chronic gingivostomatitis is considered to have a multifactorial etiology, with viral,5,8 bacterial,6,9 and immune5 factors suggested as causal. Conditions such as periodontitis and FRLs have also been suggested to play a role in FCGS.2 Diagnosis can be made on the basis of clinical findings, but determining the full extent of the dental lesions requires probing and full-mouth dental radiography.10 The diagnosis of FCGS may be confirmed with histologic analysis of affected tissues, typically revealing a lymphoplasmacytic infiltrate in the mucosa and submucosa.5 Although the soft tissue aspects of FCGS are well characterized, limited data are available regarding the degree and extent of hard tissue involvement.
The veterinary literature contains no systematic, controlled investigations that include evaluation of dental radiographs of a large number of cats with FCGS. It has been reported that only cats severely affected by FCGS have periodontal disease, whereas most have no dental disease11; there is no indication whether this claim was based on probing and dental radiography or solely on clinical appearance. Other investigators4 provide a vague description of the degree of dental disease in cats with FCGS and report that few patients studied required and underwent dental treatment.
A limited number of reports of case series that include radiographic findings of cats with FCGS have been published.7,12,13 Periodontitis has been reported in certain subtypes of FCGS, whereas other subtypes were described as free of periodontal disease.7,12 Retained roots12 and FRL7,12 are also reported in association with FCGS. A common issue in these reports is that not all cats with FCGS are described as having caudal stomatitis,10,12 or the results are not reported separately for cats with and without caudal stomatitis.7 Other reports11 do not provide details of radiographic findings. One study13 of cats with caudal stomatitis reported radiographic findings consisting of horizontal bone loss with high prevalences of FRL and retained roots. An increased OR for retained roots has been reported in cats with FCGS.14
Dental radiography is used to evaluate the presence and extent of lesions involving the hard tissues of the dentoalveolar complex. The distance between the alveolar margin and the CEJ is the most widely used criterion to evaluate periodontal health,15,16 with a distance > 1 mm considered abnormal in cats.15,17 Alveolar bone loss in periodontal disease can be classified as horizontal or vertical. Horizontal bone loss is characterized by a reduction in alveolar margin height relative to the CEJ, with the alveolar margin remaining perpendicular to the long axis of the tooth roots.18 Vertical bone loss occurs in an oblique direction so that the base of the defect is located apical to the surrounding bone.18 In multirooted teeth, progression of either type of bone loss can result in involvement of the furcation area.18 Buccal bone expansion is an idiopathic condition in cats associated with vertical bone loss; this appears as an increase in the thickness (> 2 mm)15 of the alveolar bone and widening of the periodontal ligament space buccal to the canine teeth.
In addition to alveolar bone loss, dental hard tissue abnormalities may include several types of tooth resorption. In humans and dogs, 7 types of tooth resorption, each with different radiologic characteristics, are known19; a similar evaluation has not been performed for cats. In addition, FRLs occur in cats and are characterized by idiopathic resorption of tooth substance,20 commonly starting at the CEJ,21 leading to tooth weakening and potentially fracture of the tooth and loss of the tooth crown. Retained roots are often a result of FRL and may contribute to persistent local inflammation.15,22 Of the 7 types of tooth resorption that occur in dogs, the 2 most common are external inflammatory root resorption and external replacement resorption.19 External inflammatory root resorption is a distinct entity occurring in response to periodontal ligament injury or inflammation.19 This appears radiographically as loss of root substance associated with evidence of periodontitis or periapical inflammation.19 External replacement resorption, in which the periodontal ligament is progressively replaced with alveolar bone, results in fusion of the cementum with the surrounding bone.19 The prevalences of external inflammatory root resorption and external replacement resorption in cats with FCGS have not been investigated. According to the American Veterinary Dental College's tooth resorption classification guidelines,23 type 1 resorption refers to a tooth with focal or multifocal radiolucency with an intact periodontal ligament, whereas type 2 resorption refers to a tooth with alteration of the periodontal ligament space and decreased radioopacity in part of the tooth. Feline resorption lesions may be classified as type 1 or 2, which to some extent overlaps with external inflammatory or external replacement resorption, respectively. Fracture of the crown of a tooth generally occurs because of trauma and can be classified as complicated (with pulp exposure) or uncomplicated (without pulp exposure).
Periodontitis is a progressive disease characterized by cyclic activity and quiescence,24 which results in loss of periodontal attachment and, eventually, tooth loss. In addition, the inflammatory process in periodontitis can affect the integrity of tooth structure and may be seen radiographically as external inflammatory root resorption.19 Feline chronic gingivostomatitis, on the other hand, is a chronic inflammatory process considered to be clinically continuous and progressive in the absence of treatment. As such, it is reasonable to conclude that FCGS would contribute to the progression of periodontitis.
The purposes of the study reported here were to determine the distribution, patterns, and severity of alveolar bone loss and prevalence of FRL, tooth fractures, retained roots, and external inflammatory root resorption or external replacement resorption in cats with FCGS, compared with cats with other oral diseases. Feline resporptive lesions have been reported in association with FCGS, and evaluation of these specific types of resorption lesions would allow comparison of prevalence of resorption of an inflammatory cause (external inflammatory root resorption) with that of a noninflammatory cause (external replacement resorption). A secondary aim was to determine whether age, sex, or breed was associated with FCGS.
Materials and Methods
Case and control selection criteria—Medical records of all cats examined by the Dentistry and Oral Surgery Service at the William R. Pritchard Veterinary Medical Teaching Hospital, University of California-Davis, between January 2002 and February 2012 were reviewed. Conventional full-mouth radiographs were routinely obtained for all new adult feline patients undergoing dental treatment during this period. Cats with FCGS for which full-mouth dental radiographs were obtained, along with age-matched cats without FCGS treated for another oral disease within 1 year, were included. Other oral diseases included periodontal disease, FRL, head trauma, oral mass, tooth fracture, gingival enlargement, and cleft palate.
The diagnosis of FCGS was made on the basis of history and clinical findings of caudal stomatitis, gingivitis, and buccal mucositis, with or without involvement of the palate, pharynx, and tongue. Presence of caudal stomatitis was required for inclusion in the FCGS group.2 For cats examined more than once, only the first set of full-mouth radiographs obtained during this time period was included in the study.
Procedures—The age, sex, and breed of each cat were obtained from medical records. Cats were grouped according to breed (mixed breed vs purebred) and age (1 to 4 years, 5 to 8 years, 9 to 12 years, and ≥ 13 years). Although detailed radiology reports were available, these reports were not used as the basis for data collection. To ensure consistency in evaluating data, all full-mouth radiographs were reviewed and data were recorded by the primary author; most of these were also reviewed by the second author. Radiographs were evaluated on a medical-grade radiographic viewer with a magnifying loupe.22,a
All radiographs obtained during this time period were on size 0, 2, or 4 conventional dental radiographic films.b Standardized radiographic techniques25 were used to prevent elongation or foreshortening and to allow accurate measurements of bone loss for assessment of periodontal status. Ten views were obtained for each cat evaluated.25 As described,25 the bisecting angle technique was used to obtain occlusal views of the maxillary and mandibular incisor and canine teeth and lateral views of the maxillary and mandibular canine teeth. The extraoral near-parallel technique was used to obtain images of the maxillary premolar and molar teeth, and the parallel technique was used to obtain images of the mandibular premolar and molar teeth.
Dental radiographs were evaluated to determine the presence, patterns, extent, and severity of periodontitis. Number of teeth involved and measurements of horizontal and vertical bone loss were recorded to determine extent and severity. Extent and severity were determined on the basis of criteria that used the number of teeth present for each cat, extrapolated from the classification used in humans.26 Extent of periodontitis was categorized as focal disease affecting 1 tooth, localized disease affecting < 25% of teeth present, semigeneralized disease affecting 25% to 50% of teeth present, and generalized disease affecting > 50% of teeth present. Severity of periodontitis was determined by recording the degree of bone loss at the most severely affected tooth (or teeth): mild disease, < 25% alveolar bone loss; moderate disease, 25% to 50% alveolar bone loss; and severe disease, > 50% alveolar bone loss. Numbers of teeth affected by horizontal and vertical bone loss were also recorded. In addition, presence or absence of bone loss affecting at least 1 mandibular first molar tooth, number of teeth with furcation involvement, and whether BBE was absent, present at 1 canine tooth, or present at > 1 canine tooth were recorded.
Number of teeth affected by resorption (FRL, external inflammatory root resorption, or external replacement resorption) and number of teeth with crown fractures (complicated and uncomplicated) were recorded for each cat. When retained roots were present, the number of teeth affected, rather than the number of root remnants present, was recorded. A tooth with at least 1 retained root was included in the number of teeth counted per cat. The authors considered the use of the American Veterinary Dental College's classification system for tooth resorption. However, one of the goals of the study was to differentiate external inflammatory resorption, external replacement resorption, and FRL to achieve the goal of assessing prevalence of these lesions in cats with FCGS.
For the American Veterinary Dental College's tooth resorption classification, external inflammatory resorption is type 1, external replacement resorption is type 2, and FRL can be classified into either category. Because of this overlap in classification, it was decided to use terminology historically used for classification of dog and human resorption lesions (external inflammatory and external replacement resorption). In addition, the term FRL, rather than the American Veterinary Dental College–recommended term tooth resorption, was used to avoid confusion with the other resorptive lesions.
Statistical analysis—Comparison of matched case and control data with respect to age, breed, sex, extent of and severity of alveolar bone loss, numbers of teeth per cat affected by horizontal and vertical bone loss, whether alveolar bone loss was present at 1 or both mandibular first molar teeth, numbers of teeth per cat affected by furcation involvement, BBE, FRL, external inflammatory root resorption, external replacement resorption, complicated and uncomplicated crown fracture, and retained roots was made by means of conditional logistic regression. Prevalence ORs and 95% CIs are reported for all significant differences. For all comparisons, P < 0.05 was considered significant. Data for extent and severity of periodontal disease and bone loss at mandibular first molar teeth are presented as frequency distributions. Data for number of teeth present, patterns of bone loss, furcation involvement, BBE, FRL, external inflammatory resorption lesions, external replacement resorption lesions, and tooth fractures are presented as median (range). Cats missing both mandibular first molar teeth were excluded from statistical analysis of bone loss at this site.
Results
One hundred one cats with FCGS and 101 age-matched controls without FCGS treated within 1 year were included in the study. In 35 (35%) cats with FCGS, this diagnosis was made on the basis of clinical findings alone, and in 66 (65%) cats, the clinical diagnosis was confirmed on histologic evaluation. Of the cats without FCGS, 77 cats were treated for periodontal disease (53 with periodontal disease alone, 19 also with FRL, 4 also with tooth fracture, and 1 also with oronasal fistula), 10 were treated for head trauma, 3 were treated for FRL without periodontal disease, 3 were treated for malocclusion, 3 were treated for oral masses, 2 were treated for tooth fracture, 2 were treated for gingival enlargement, and 1 was treated for cleft palate. Of 101 cats with FCGS, 54 (53%) were neutered males, 2 (2%) were sexually intact females, and 45 (45%) were spayed females; 85 (84%) were mixed breed, and 16 (16%) were purebred. Of 101 cats without FCGS, 1 (1%) was a sexually intact male, 56 (55%) were neutered males, 2 (2%) were sexually intact females, and 42 (42%) were spayed females; 82 (81%) were mixed breed, and 19 (19%) were purebred. Of purebred cats with FCGS, 3 each of Himalayan Persian, Maine Coon, and Siamese breeds were present. One each of Abyssinian, American Curl, British Shorthair, Manx, Persian, Ragdoll, and Tonkinese were present. Cats had a median age of 6 years (range, 1 to 16 years), with 36 (36%) cats 1 to 4 years of age, 36 (36%) 5 to 8 years, 22 (22%) 9 to 12 years, and 7 (7%) 13 to 16 years. There were no differences between cats with and without FCGS with respect to sex or breed.
For the cats with FCGS, 2,656 teeth were examined, whereas for cats without FCGS, 2,838 teeth were examined. Cats with FCGS had a median of 28 teeth present (range, 4 to 30 teeth), whereas cats without FCGS had a median of 29 teeth present (range, 17 to 30 teeth); this difference (OR, 0.86; 95% CI, 0.76 to 0.94) was significant (P < 0.001).
All cats with FCGS had some degree of alveolar bone loss. Of cats with FCGS, 23 (23%) had localized bone loss, 42 (42%) had semigeneralized bone loss, and 36 (36%) had generalized bone loss. Of cats without FCGS, 25 (25%) had no bone loss, 13 (13%) had focal bone loss, 35 (35%) had localized bone loss, 20 (20%) had semigeneralized bone loss, and 8 (8%) had generalized bone loss. The median distribution of alveolar bone loss in cats with FCGS was semigeneralized and ranged from localized to generalized, whereas the median distribution in cats without FCGS was localized and ranged from absent to generalized. Compared with matched cats without FCGS, cats with FCGS had semigeneralized (OR, 47.94; 95% CI, 7.71 to ∞) and generalized (OR, 78.50; 95% CI, 11.77 to ∞) alveolar bone loss significantly (P < 0.001) more often than cats without FCGS. More cats without FCGS had localized alveolar bone loss (P < 0.001; OR, 17.51; 95% CI, 2.91 to ∞), compared with cats that had FCGS. Because no cats with FCGS had focal disease, comparisons could not be made for this extent category.
Alveolar bone loss (periodontitis) was more severe in cats with FCGS than those without. Eight (8%), 35 (35%), and 58 (57%) cats with FCGS had mild, moderate, and severe bone loss, respectively, whereas 25 (25%), 38 (38%), 19 (19%), and 19 (19%) cats without FCGS had absent, mild, moderate, and severe bone loss, respectively. Cats with FCGS had significantly (P < 0.001) higher prevalences of moderate (OR, 43.22; 95% CI, 6.75 to ∞) and severe (OR, 54.02; 95% CI, 8.77 to ∞) alveolar bone loss than cats without FCGS. Although not significant (P = 0.076), cats without FCGS had a higher prevalence of mild alveolar bone loss (OR, 6.06; 95% CI, 0.85 to ∞) than cats with FCGS.
Numbers of teeth per cat affected by horizontal alveolar bone loss (Figures 1 and 2) also differed significantly (P < 0.001) between groups (OR, 1.23; 95% CI, 1.13 to 1.33), with more cats with FCGS affected than those without. Cats with FCGS also had more teeth affected by vertical alveolar bone loss than cats without FCGS (OR, 1.18; 95% CI, 0.98 to 1.44), although the difference was not significant (P = 0.064). Cats with FCGS had medians of 10 (range, 0 to 31) and 1 (range, 0 to 10) teeth affected by horizontal and vertical bone loss, respectively, whereas those without FCGS had medians of 4 (range, 0 to 28) and 0 (range, 0 to 8) teeth affected, respectively. Cats with FCGS were significantly (P < 0.001) more likely to have teeth with furcation involvement than cats without FCGS (OR, 1.35; 95% CI, 1.18 to 1.56). Of cats with FCGS, the median number of teeth with furcation involvement was 3 (range, 0 to 10), whereas cats without FCGS had a median of 0 (range, 0 to 10).
Representative lateral radiographic view of the left mandible of a cat affected by horizontal alveolar bone loss. Notice mild (white arrow), moderate (black arrow), and severe (arrowhead) horizontal bone loss at the left mandibular fourth premolar tooth, the left mandibular third premolar tooth, and distal root of the left mandibular first molar tooth, respectively.
Citation: Journal of the American Veterinary Medical Association 244, 3; 10.2460/javma.244.3.339
Representative lateral radiographic view of the left mandible of a cat affected by horizontal alveolar bone loss. Notice mild (white arrow), moderate (black arrow), and severe (arrowhead) horizontal bone loss at the left mandibular fourth premolar tooth, the left mandibular third premolar tooth, and distal root of the left mandibular first molar tooth, respectively.
Citation: Journal of the American Veterinary Medical Association 244, 3; 10.2460/javma.244.3.339
Representative lateral radiographic view of the left mandible of a cat affected by horizontal alveolar bone loss. Notice mild (white arrow), moderate (black arrow), and severe (arrowhead) horizontal bone loss at the left mandibular fourth premolar tooth, the left mandibular third premolar tooth, and distal root of the left mandibular first molar tooth, respectively.
Citation: Journal of the American Veterinary Medical Association 244, 3; 10.2460/javma.244.3.339
Representative lateral radiographic view of the left mandible of a cat affected by vertical alveolar bone loss. Notice vertical bone loss (white arrow) at the mesial root of the left mandibular first molar tooth with external inflammatory root resorption (black arrow) and calculus (white arrowhead), vertical and horizontal bone loss with furcation involvement (black arrowhead), and FRL (open arrow) at the mesial aspect of the crown adjacent to the furcation of the left mandibular fourth premolar tooth.
Citation: Journal of the American Veterinary Medical Association 244, 3; 10.2460/javma.244.3.339
Representative lateral radiographic view of the left mandible of a cat affected by vertical alveolar bone loss. Notice vertical bone loss (white arrow) at the mesial root of the left mandibular first molar tooth with external inflammatory root resorption (black arrow) and calculus (white arrowhead), vertical and horizontal bone loss with furcation involvement (black arrowhead), and FRL (open arrow) at the mesial aspect of the crown adjacent to the furcation of the left mandibular fourth premolar tooth.
Citation: Journal of the American Veterinary Medical Association 244, 3; 10.2460/javma.244.3.339
Representative lateral radiographic view of the left mandible of a cat affected by vertical alveolar bone loss. Notice vertical bone loss (white arrow) at the mesial root of the left mandibular first molar tooth with external inflammatory root resorption (black arrow) and calculus (white arrowhead), vertical and horizontal bone loss with furcation involvement (black arrowhead), and FRL (open arrow) at the mesial aspect of the crown adjacent to the furcation of the left mandibular fourth premolar tooth.
Citation: Journal of the American Veterinary Medical Association 244, 3; 10.2460/javma.244.3.339
Of 101 cats with FCGS, 95 had at least 1 mandibular first molar tooth present; 100% of these teeth had alveolar bone loss. Of the 101 cats without FCGS, 97 had at least 1 mandibular first molar tooth present; only 42% of these teeth had alveolar bone loss. This difference (OR, 80.27; 95% CI, 14.66 to ∞) was significant (P < 0.001).
There was no significant difference in number of teeth affected by BBE (Figure 3) between cats with and without FCGS. Of cats with FCGS, 44 (44%) had no teeth affected by BBE, 8 (8%) had 1 tooth affected, and 49 (49%) had ≥ 2 teeth affected, whereas of cats without FCGS, 50 (50%) had no teeth affected, 11 (11%) had 1 tooth affected, and 40 (40%) had ≥ 2 teeth affected. Both groups of cats had a median of 1 (range, 0 to 2) tooth affected by BBE.
Representative occlusal radiographic view of the maxilla of a cat affected by BBE. Notice BBE at the right and left maxillary canine teeth (white arrows), root fracture at the right maxillary first incisor tooth (open arrow), and retained root (arrowhead) at the left maxillary first incisor tooth.
Citation: Journal of the American Veterinary Medical Association 244, 3; 10.2460/javma.244.3.339
Representative occlusal radiographic view of the maxilla of a cat affected by BBE. Notice BBE at the right and left maxillary canine teeth (white arrows), root fracture at the right maxillary first incisor tooth (open arrow), and retained root (arrowhead) at the left maxillary first incisor tooth.
Citation: Journal of the American Veterinary Medical Association 244, 3; 10.2460/javma.244.3.339
Representative occlusal radiographic view of the maxilla of a cat affected by BBE. Notice BBE at the right and left maxillary canine teeth (white arrows), root fracture at the right maxillary first incisor tooth (open arrow), and retained root (arrowhead) at the left maxillary first incisor tooth.
Citation: Journal of the American Veterinary Medical Association 244, 3; 10.2460/javma.244.3.339
Regarding tooth resorption, 62 (61%), 49 (49%), and 13 (13%) cats with FCGS had at least 1 tooth affected by FRL (Figures 2 and 4), external inflammatory resorption (Figure 2), or external replacement resorption, respectively; 65 (64%), 24 (24%), and 19 (19%) cats without FCGS had at least 1 tooth affected by FRL, external inflammatory resorption, or external replacement resorption, respectively. These differences were significant (P = 0.001) only for external inflammatory root resorption (OR, 1.62; 95% CI, 1.23 to 2.25), with more lesions per cat in cats with FCGS. Of cats with FCGS, the median number of teeth with FRL, external inflammatory resorption, and external replacement resorption per cat was 1 (range, 0 to 16), 0 (range, 0 to 8), and 0 (range, 0 to 8), respectively. Cats without FCGS had a median of 2 (range, 0 to 14) teeth affected by FRL, 0 (range, 0 to 5) teeth affected by external inflammatory resorption, and 0 (range, 0 to 9) teeth affected with external replacement resorption.
Representative occlusal radiographic view of the mandibles of a cat affected by FRL. Notice FRL at the right mandibular canine tooth (white arrow) and BBE at both mandibular canine teeth (open arrows; right more affected than left).
Citation: Journal of the American Veterinary Medical Association 244, 3; 10.2460/javma.244.3.339
Representative occlusal radiographic view of the mandibles of a cat affected by FRL. Notice FRL at the right mandibular canine tooth (white arrow) and BBE at both mandibular canine teeth (open arrows; right more affected than left).
Citation: Journal of the American Veterinary Medical Association 244, 3; 10.2460/javma.244.3.339
Representative occlusal radiographic view of the mandibles of a cat affected by FRL. Notice FRL at the right mandibular canine tooth (white arrow) and BBE at both mandibular canine teeth (open arrows; right more affected than left).
Citation: Journal of the American Veterinary Medical Association 244, 3; 10.2460/javma.244.3.339
The presence of dental fractures and retained roots (Figure 3) differed between the 2 groups. Of cats with FCGS, 5 (5%) had at least 1 complicated crown fracture, 9 (9%) had at least 1 uncomplicated crown fracture, and 57 (56%) had at least 1 tooth with retained roots. In cats that did not have FCGS, 14 (14%) had at least 1 complicated crown fracture, 21 (21%) had at least 1 uncomplicated crown fracture, and 28 (28%) had at least 1 tooth with retained roots. Cats without FCGS had significantly more teeth affected by crown fractures (complicated [OR, 0.47; 95% CI, 0.21 to 0.86; P = 0.008] and uncomplicated [OR, 0.42; 95% CI, 0.14 to 0.93; P = 0.029]) than cats with FCGS. Cats with FCGS had medians of 0 (range, 0 to 2) teeth per cat affected by both complicated and uncomplicated crown fractures, whereas cats without FCGS had medians of 0 (range, 0 to 5) and 0 (range, 0 to 3) teeth per cat affected by complicated and uncomplicated crown fractures, respectively. By contrast, cats with FCGS, with a median of 1 (range, 0 to 14) tooth with retained roots, were significantly (P < 0.001) more likely to have retained roots than cats without FCGS (median, 0 [range, 0 to 8]; OR, 1.46; 95% CI, 1.20 to 1.87).
Discussion
The diagnosis of FCGS can often be made on the basis of clinical findings alone2,8,12,27 and rarely requires biopsy.28 This was supported in the present study by the high proportion of cats with FCGS in which a diagnosis of FCGS was histologically confirmed.
With respect to signalment, the findings were consistent with another study29 regarding lack of sex predilection for FCGS. Historically, an increased prevalence of FCGS in Siamese, Abyssinian, Persian, Himalayan Persian, and Burmese cats has been reported.11,30 In the present study, there was no difference between FCGS and control groups regarding breed representation, and similar to previous findings,29 breeds represented by > 1 cat were among the more popular cat breeds. Of cats with FCGS, 35.5% were ≤ 4 years old, and another 35.5% were 4 to 8 years old, resulting in 71% being 8 years old or younger. Because the control group was selected on the basis of age, there were no age differences between the 2 groups. Previous investigators29 report peaks at 1 to 5 years and 10 to 13 years in the age distribution of cats with FCGS. This pattern was not apparent in the present study.
Cats with FCGS had more than twice the number of radiographically absent teeth than did cats without FCGS. The finding of more teeth missing in cats with FCGS appears to be consistent with increased severity of periodontitis. Although there are several other causes for tooth loss, such as FRL and previous tooth extractions, FRLs were not found at increased rates in cats with FCGS. Because retained roots were not counted as absent teeth in the present study, the increased prevalence of retained roots in cats with FCGS did not appear to be the immediate cause of the larger number of missing teeth in cats with FGCS, unless complete resorption of the roots had occurred.
Cats affected by FCGS typically have inflammation of the oral mucosa that is disproportionally severe, compared with visible dental disease.29 Limited radiographic data are available in the veterinary literature from cats with FCGS, mostly from small case series and uncontrolled studies. Cats with FCGS with no evidence of alveolar bone loss have been described,7,12 although none were found in the present study. Results of the present study suggested that FCGS was associated with more advanced and widespread alveolar bone loss than was present in cats without FCGS. The present study revealed not only that all cats with FCGS had periodontitis, but also that the periodontitis was either moderate or severe and semigeneralized to generalized in most of these cats. The absence of alveolar bone loss in some cats with FCGS reported by some authors may be explained by the fact that case selection criteria in the present study limited entry to cats with caudal stomatitis, eliminating cats with other oral inflammatory diseases with similar appearance. Evolution of patterns of case referral to a tertiary hospital may have also occurred. It is possible that, during the past decade, referring veterinarians have been more inclined to treat cats with FCGS medically for extended periods, allowing underlying periodontal disease to progress prior to referral for surgical treatment. Also, radiographic technique and interpretation in the present study were focused on detecting early evidence of lesions, and radiographs were viewed under optimal conditions with a magnifying loupe22; these conditions may or may not have been the same for other reports.
In this study, radiographic periodontal findings in cats with FCGS were dominated by a pattern of horizontal alveolar bone loss, similar to that reported for cats in general.13 The alveolar bone loss was more severe and the distribution was more generalized in cats with FCGS than the age-matched cats with other oral diseases. Although horizontal bone loss was predominant and affected significantly more teeth per cat in cats with FCGS than those without, vertical bone loss was also present to a larger degree in cats with FCGS than those without, although this finding was not significant. As a result of this increased bone loss, cats with FCGS also had higher numbers of teeth affected by furcation exposure. These differences may be further illustrated by evaluating the distribution of periodontitis as absent or focal or localized versus semigeneralized or generalized and evaluating the severity as absent or mild versus moderate or severe. In this investigation, 77% of cats with FCGS had semigeneralized or generalized alveolar bone loss, whereas only 28% of cats without FCGS had this distribution. With respect to severity, 93% of cats with FCGS had moderate or severe disease, compared with 38% of cats that did not have FCGS.
Cats with FCGS more consistently had bone loss at the mandibular first molar teeth than cats without FCGS, a finding that was also reported by Harvey13 in 1990, but with a lower frequency. The finding that 100% of cats with FCGS had alveolar bone loss at the mandibular first molar teeth likely reflected the degree of inflammation of the caudal portion of the oral cavity affecting both soft and hard tissues.
The etiology of BBE in cats has not been established. This phenomenon is commonly associated with periodontitis.31 Given that there was no difference in frequency of BBE between cats with and without FCGS, it appears that BBE was not associated with FCGS. This was consistent with the typical clinical finding of caudal oral inflammation with less frequent involvement of canine teeth.
As would be expected with widespread and severe periodontitis, cats with FCGS also had a higher prevalence of external inflammatory root resorption than cats without FCGS. This finding has important clinical implications because external inflammatory root resorption may predispose to root fractures during extraction. Because retained root fragments are a potential cause of persistent stomatitis following premolar-molar or full-mouth extractions, complete extraction of all teeth and root remnants is recommended.10,27 If pre-extraction radiographs are routinely obtained in cats with FCGS, identification of teeth with external inflammatory root resorption will allow modification of the surgical plan with consideration to prevent root fractures.
Retained roots are an outcome of root fracture. This may be caused by tooth weakening due to FRL or trauma (either iatrogenic from tooth extraction procedures or from head trauma). Because determining the cause of tooth fracture is not possible on the basis of radiographic findings, retained roots were reported as such. It is plausible to speculate that, given that there were no significant differences between the groups regarding FRL and given that cats with FCGS had fewer crown fractures, this increased prevalence of retained roots in cats with FCGS could have been caused by tooth weakening associated with the higher number of teeth affected by external inflammatory root resorption in these cats. It is also possible that retained roots resulted from previous extraction attempts; information regarding previous treatment was not collected in the present study, so comparison of frequency of retained roots in cats that had previously undergone extractions, versus those that had not, could not be performed.
The finding of an increased prevalence of dental fractures in cats without FCGS may be attributable to inclusion criteria, because 10 cats in this group were evaluated for head trauma and 2 for tooth fracture specifically. Alternately, cats with FCGS may be less active and therefore less predisposed to participate in activities that may result in tooth fracture.
The present study found no significant difference in prevalence of FRL between cats with and without FCGS, consistent with previously reported findings in cats with FCGS; Lommer and Verstraete32 found no significant difference in prevalence of FRL between cats with (59%) and without (46%) FCGS. Other studies33,34 have revealed similar prevalences of FRL (61% to 67%, based on radiographic findings) in cats without FCGS. It is possible that some of the retained roots observed more frequently in cats with FCGS than those without may have been a result of FRL, but because the prevalence of FRL was the same for both groups, it is expected that the number of retained roots caused by FRL would be the same for both groups.
The frequency and variety of dental lesions documented radiographically, even in cats without FCGS, reinforced the conclusion of a previous study14 highlighting the importance of full-mouth radiographs for adequate diagnosis of dental disease, most of which is not visible on oral examination. Several variables assessed in this investigation indicated that the persistent oral inflammation in cats with FCGS was associated with substantial alveolar bone loss and external inflammatory root resorption. Full-mouth dental radiography is a crucial component of the diagnostic testing for cats being treated for FCGS.10,12
ABBREVIATIONS
| BBE | Buccal bone expansion |
| CEJ | Cementoenamel junction |
| CI | Confidence interval |
| FCGS | Feline chronic gingivostomatitis |
| FRL | Feline resorptive lesion |
PEAK magnifying loupe, 0.1 mm, GWJ Co, Hacienda Heights, Calif.
Intraoral E-speed film, Kodak Dental, Rochester, NY.
References
1. Johnessee JS, Hurvitz AI. Feline plasma cell gingivitis-pharyngitis. J Am Anim Hosp Assoc 1983; 19: 179–181.
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