Periodontal disease is a common acquired condition in dogs that can cause substantial morbidity and related health-care costs.1 Untreated periodontal disease can lead to tooth loss, jaw fractures, facial abscesses, and oronasal fistulas2 and can contribute to or worsen concomitant conditions.3
Periodontal disease is categorized in stages, ranging from stage 0 (no disease) to stage 4 (end-stage or severe disease). Stage 1 periodontal disease (also known as gingivitis) is generally reversible through home care and professional dental care. In contrast, stage 2 periodontal disease, which is characterized by the beginning of alveolar bone loss, can be controlled and stabilized but cannot be reversed without professional treatment.4,5 On oral examination of non-sedated dogs, stages 1 and 2 are often indistinguishable from one another. Intraoral examination coupled with dental probing and intraoral radiography are required for proper staging. General anesthesia is required to accomplish this safely and effectively in dogs. Stages 3 and 4 are characterized by increasing loss of alveolar bone and represent moderate and severe periodontal disease, respectively, requiring advanced surgical treatment or tooth extraction.
Periodontal disease is believed to result from a complicated interaction between bacteria in the plaque biofilm, the immune response of the host, and the structure and microstructure of the teeth, gingiva, periodontal ligament, and supporting bones.6 Risk factors for periodontal disease in dogs include tooth crowding, large tooth-to-jaw ratios in small breed dogs, persistent primary teeth, malocclusions, developmental anomalies, trauma, nonabrasive diets, and genetic factors.4
Development of effective strategies to manage this serious condition in dogs has been hampered by a lack of clinical trials designed to evaluate and compare the effects of various treatments. Closed root planing has been shown to help reduce periodontal pocket depth for pockets with depths > 3 to < 6 mm and is the accepted standard of care.4,7 Current recommendations for the management of stage 2 periodontal disease include professional dental scaling, CRP, local antimicrobial gel application, and dental sealant application following cleaning. In addition, home care protocols that include frequent tooth brushing, diets formulated for dental benefits, dental chews, and water additives are recommended.8
Closed root planing of periodontal pockets involves use of a hand curette or ultrasonic scaler tip to completely remove all plaque and calculus within the pocket and can be effective for dogs with periodontal pockets between 3 and 6 mm deep. Pockets deeper than 6 mm, which are usually categorized as stage 3 periodontal disease, require open root planing, which involves creation of a gingival flap to provide complete visibility of and access to the bottom of the pocket.7
Two antimicrobial gels are commercially available to veterinarians for the local treatment of periodontal pockets: one containing 8.5% doxycycline hyclate and the other containing 2% clindamycin hydrochloride.9 The doxycycline product consists of an antimicrobial powder contained within a slowly dissolving polymer gel, and the clindamycin product consists of a hydrated salt in a matrix that gels at body temperature. Both are approved by the US FDA for use in nonpregnant or lactating dogs > 1 year of age. Although concerns about transient pain, sensitivity, or allergic reactions have been reported for humans,10 these drugs are considered safe for dogs. Nevertheless, little evidence exists regarding the efficacy of these agents, and to the authors’ knowledge, the benefit of CRP alone has not been simultaneously compared with the benefits of multiple adjunctive local antimicrobial treatments to manage periodontal disease.
The purpose of the study reported here was to compare the effectiveness of 3 contemporary treatments—CRP alone, CRP plus 8.5% doxycycline gel application, and CRP plus 2% clindamycin gel application—for the treatment of dogs with periodontal pockets between 3 and 6 mm deep by comparing gingival index, plaque index, calculus index, and periodontal pocket depth measurements. We hypothesized that there would be no significant difference among treatments in the amount of improvement in periodontal disease severity observed between before and 12 weeks after treatment.
Materials and Methods
Dogs
The protocol for this randomized, blinded, controlled clinical trial was approved by the Institutional Animal Care and Use Committee of the Caspary Institute at the Animal Medical Center. Dogs brought to the Animal Medical Center in New York, NY, for treatment of periodontal disease between December 1, 2014, and July 1, 2016, were considered for inclusion in the study. Dogs between 1.5 and 13 years of age and of any breed, sex, or body weight were eligible for participation. American Society of Anesthesiologists physical status was assessed on the basis of medical history, physical examination findings, and results of CBC and serum biochemical analysis performed ≤ 1 month prior to treatment, and dogs with any status other than 1 or 2 were excluded. Dogs were also excluded if they had gingival hyperplasia (to avoid inclusion of pseudopockets), neoplasia, autoimmune disease, or uncontrolled systemic disease or had received antimicrobials (other than as assigned in this study) or corticosteroid drugs within 60 days before or after treatment or at any point within the 12 weeks following treatment. Additional exclusion criteria were applied after initial periodontal measurements were made. Owner consent was obtained for all participating dogs.
Measurements
Measurements of periodontal disease severity were performed by 2 licensed veterinary technicians before treatment, while dogs were anesthetized (0 weeks), and 12 weeks after treatment, while the dogs were sedated. These technicians were blinded to treatment assignment. Drug protocols for general anesthesia and sedation were selected by the attending anesthesiologist on the basis of dog temperament, age, and overall health.
Before inclusion in the study, each dog was thoroughly screened to ensure it had periodontal pockets with depths ranging from 3.5 to 5.5 mm affecting 1 to 3 teeth, and dogs failing to meet these criteria were excluded from the study. Both technicians graded the severity of periodontal disease on a scale of 0 to 3 for each of 3 indices (gingival, plaque, and calculus indices11; Appendix and measured the periodontal pocket depths in millimeters with a standard periodontal probe. The data recorded by each technician for each tooth were then combined to yield a mean result for each measured variable. If a dog had > 3 teeth with periodontal disease, then the 3 deepest periodontal pockets (still < 6 mm deep) were selected for inclusion.
Pocket depths were measured with a Marquis probea (with markings at 3, 6, 9, and 12 mm) or a Williams probea (with markings at 1, 2, 3, 5, 7, 8, 9, and 10 mm). At the authors’ facility, the 2 probes are used interchangeably. To measure the pocket depth, the probe was gently inserted into the sulcus of each tooth at 8 circumferential locations that encompassed mesial, mesiobuccal, buccal, distobuccal, distal, distopalatal-distolingual, palatal-lingual, and mesiopalatal-mesiolingual surfaces. For each tooth, the location and depth (rounded to the nearest 0.5-mm increment) of the deepest periodontal pocket were recorded, as measured from the bottom of the deepest part of the pocket to the gingival margin (Figure 1).
Photographs of a 7-year-old spayed female Yorkshire Terrier before (A) and 12 weeks after (B) treatment for periodontal disease. Pocket depth was assessed by gently inserting the tip of a periodontal probe into the periodontal pocket and using the probe gradations to measure the distance from the bottom of the pocket (asterisk) to the gingival margin. Prior to CRP, a Marquis periodontal probe was used, revealing a pocket depth of 3.5 mm surrounding the right mandibular canine tooth (A). Twelve weeks after treatment, a Williams periodontal probe was used, revealing that the depth of this pocket had decreased to 2.0 mm (B). The gingival margin prior to treatment is indicated (arrow).
Citation: Journal of the American Veterinary Medical Association 254, 3; 10.2460/javma.254.3.373
Photographs of a 7-year-old spayed female Yorkshire Terrier before (A) and 12 weeks after (B) treatment for periodontal disease. Pocket depth was assessed by gently inserting the tip of a periodontal probe into the periodontal pocket and using the probe gradations to measure the distance from the bottom of the pocket (asterisk) to the gingival margin. Prior to CRP, a Marquis periodontal probe was used, revealing a pocket depth of 3.5 mm surrounding the right mandibular canine tooth (A). Twelve weeks after treatment, a Williams periodontal probe was used, revealing that the depth of this pocket had decreased to 2.0 mm (B). The gingival margin prior to treatment is indicated (arrow).
Citation: Journal of the American Veterinary Medical Association 254, 3; 10.2460/javma.254.3.373
Photographs of a 7-year-old spayed female Yorkshire Terrier before (A) and 12 weeks after (B) treatment for periodontal disease. Pocket depth was assessed by gently inserting the tip of a periodontal probe into the periodontal pocket and using the probe gradations to measure the distance from the bottom of the pocket (asterisk) to the gingival margin. Prior to CRP, a Marquis periodontal probe was used, revealing a pocket depth of 3.5 mm surrounding the right mandibular canine tooth (A). Twelve weeks after treatment, a Williams periodontal probe was used, revealing that the depth of this pocket had decreased to 2.0 mm (B). The gingival margin prior to treatment is indicated (arrow).
Citation: Journal of the American Veterinary Medical Association 254, 3; 10.2460/javma.254.3.373
Treatment
After initial measurements were made, dogs were randomly assigned by drawing of lots from a bag to receive 1 of 3 treatments: CRP alone (n = 10), CRP plus 8.5% doxycycline hyclate gelb (12), or CRP plus 2% clindamycin hydrochloride reverse-polymer hydrogelc (12). All treatments were performed by the principal investigator (DPM), who was not blinded to the treatment group allocation.
Closed root planing of periodontal pockets was performed with a combination of ultrasonic and hand instruments. Ultrasonic scaling was performed by use of an ultrasonic piezoelectric scalerd with a universal tip. The power setting was set to 60% to avoid causing excessive damage to the delicate subgingival tissues. A sharp universal hand curettee was then used to perform root planing on all areas of the exposed root surface and to perform subgingival curettage of the soft tissue portion of the periodontal pockets. A pocket was deemed to be appropriately cleaned by visual inspection and a smooth tactile sensation.
After CRP was complete, dogs assigned to receive doxycycline or clindamycin gel were treated further and the remaining dogs were allowed to recover from anesthesia. The assigned antimicrobial gel was applied within each periodontal pocket in accordance with the manufacturer's recommendations. The doxycycline gel and powder were mixed via the supplied 2-part interlocking mixing syringes (material exchanged between syringes > 100 times), and the mixed contents were then injected into the cleaned pocket via the supplied metal canula until the pocket was just filled. Afterward, a small amount of water was lightly sprayed onto the gel for 30 seconds to cure the gel. A plastic filling instrument was then used to fully compress the gel into the pocket, ensuring all parts were below the gingival margin. The clindamycin reverse-polymer gel (no premixing required) was applied within the previously cleaned pocket until the pocket was just filled, and the gel was left to harden on its own.
Statistical analysis
Measurement and other numerical data are reported as mean ± SD or median (range). Statistical softwaref was used to compare age and body weight as well as differences in measurements between 0 and 12 weeks after treatment among treatment groups by means of ANOVA, followed by false discovery rate adjustment. Normality of the error residuals was confirmed via the Kolmogorov-Smirnoff test and visual inspection. Values of P < 0.05 were considered significant.
Results
A total of 34 dogs with 67 affected teeth were included in the study. Mean ± SD age of included dogs was 7.4 ± 2.7 years, and median body weight was 5.4 kg (11.9 lb; range, 0.6 to 35 kg [1.3 to 77 lb]). Neither age nor body weight differed significantly among the 3 treatment groups.
Canine teeth were the most common tooth type among the 67 affected teeth (n = 32 [48%]), followed by incisor (18 [27%]), premolar (10 [15%]), and molar (7 [10%]) teeth. Periodontal pockets most commonly involved the palatal aspect of the maxillary canine tooth (Supplementary Table S1, available at avmajournals.avma.org/doi/suppl/10.2460/javma.254.3.373).
Except for gingivitis index, no significant differences were identified among the 3 treatment groups in the amount of improvement in periodontal measurements between before and 12 weeks after treatment (Table 1). The overall degree of improvement in periodontal measurements during the 12-week study period corresponded to the severity of initial pocket depth. Teeth that were initially more severely affected (pocket depths of 5.0 to 5.5 mm) had significant improvement to the greatest degree, and teeth with less severe initial pocket depths (4.0 to 5.0 mm) also had significant improvement, but to a lesser extent. On the other hand, teeth with only mildly high initial pocket depths (3.5 to 4.0 mm) had even less improvement that was not significant (Table 2).
Mean ± SD improvements (decreases in values) in periodontal measurements between before and 12 weeks after treatment for 34 client-owned dogs (67 teeth) with periodontal disease treated by CRP of the affected tooth or teeth or CRP plus 8.5% doxycycline gel or 2% clindamycin reverse-polymer hydrogel applied to the periodontal pockets.
| Measurement | CRP (n = 10 dogs) | CRP + doxycycline gel (n = 12 dogs) | CRP + clindamycin gel (n = 12 dogs) |
|---|---|---|---|
| Gingival index | 1.0 ± 0.8 | 1.3 ± 0.9* | 1.0 ± 0.8 |
| Plaque index | 1.5 ± 0.9 | 1.3 ± 0.8 | 1.3 ± 0.9 |
| Calculus index | 1.1 ± 0.6 | 1.1 ± 0.5 | 1.2 ± 0.9 |
| Periodontal pocket depth (mm) | 1.5 ± 0.8 | 1.4 ± 0.6 | 1.3 ± 0.7 |
Indicated value differs significantly (P ≤ 0.006) from that for CRP alone or CRP plus clindamycin gel.
The 3 indices were scored from 0 to 3, with 0 generally representing healthy and 3 representing severe.
Mean ± SD decreases in mean periodontal pocket depth (mm) between before and 12 weeks after treatment for the dogs in Table 1, grouped by initial pocket depth.
| CRP (n = 10 dogs) | CRP + doxycycline gel (n = 12 dogs) | CRP + clindamycin gel (n = 12 dogs) | All dogs (n = 34) | |||||
|---|---|---|---|---|---|---|---|---|
| Initial pocket depth (mm) | No. of teeth | Value | No. of teeth | Value | No. of teeth | Value | No. of teeth | Value |
| 3.5 | 2 | 0.8 ± 0.6a | 2 | 0.9 ± 0.6a | 3 | 0.6 ± 0.2a | 7 | 0.8 ± 0.5a |
| 4.0–1.5 | 10 | 1.4 ± 0.8a | 17 | 1.2 ± 0.5a | 14 | 1.5 ± 0.4b | 41 | 1.3 ± 0.6b |
| 5.0–5.5 | 9 | 2.1 ± 0.5b | 4 | 2.0 ± 0.4b | 6 | 1.9 ± 0.8c | 19 | 2.0 ± 0.6c |
Within a column, values with different superscript letters differ significantly (P ≤ 0.03).
See Table 1 for remainder of key.
Discussion
The aim of the present study was to evaluate and compare 3 commonly used approaches to treating periodontal pockets > 3 but < 6 mm deep in dogs.
The results indicated no significant difference among the 3 treatment groups in posttreatment improvements for any measured variable except gingivitis index. Additionally, greater improvement in the depth of periodontal pockets was obtained when the initial pocket depth was at the higher end of the evaluated range (3.5 to 5.5 mm), but this improvement was similar for all 3 treatment groups. For example, an initial mean pocket depth of 5.0 to 5.5 mm had a larger degree of improvement (overall mean decrease in depth, 2.0 mm) than an initial mean pocket depth of 4.0 to 4.5 mm (overall mean decrease in depth, 1.3 mm) for all 3 treatment groups combined as well as for each group separately.
Few clinical data exist regarding the effectiveness of locally applied doxycycline gel for the treatment of periodontal disease in dogs.12,13 The 8.5% doxycycline hyclate product is a powder that, when mixed with a polymer gel, transforms to a viscous syrup and then hardens into an opaque, off-yellow, waxy periodontal pocket–conforming substance. It slowly dissolves over a period of approximately 3 to 6 weeks when applied adjacent to healthy gingival tissues, such as those present in a cleaned periodontal pocket. The doxycycline gel acts as a physical barrier to limit pocket contamination and has anticollagenase effects on the local tissues, helping to delay scar formation and encourage healthy tissue regrowth.
To the authors’ knowledge, the first report12 of local doxycycline gel application for treating periodontal disease in dogs was that of a pilot study in which a product labeled for use in humans was used. That study involved 8 research Beagles with advanced periodontal disease allocated to 2 treatment groups. One group of 4 dogs received 10% doxycycline hyclate gel applied to three 4-mm-deep periodontal pockets, without prior root planing. The other 4 dogs received a nonmedicated vehicle gel (control treatment) applied to 3 similarly sized periodontal pockets. After 7 days, the gels were removed from all dogs. Gingival index, periodontal pocket depth, and degree of gingival attachment loss were assessed at various points, revealing a mean reduction in periodontal pocket depth of 2.5 mm in the doxycycline group 16 weeks after treatment application, compared with 0.2 mm in the control group (P < 0.001).12
In a second preliminary study13 of local application of doxycycline hyclate gel to treat periodontal disease, 6 research Beagles and a veterinary doxycycline product were used. All dogs underwent ultrasonic dental scaling and polishing while anesthetized. Then, half of each dog's mouth (each containing 4 periodontal pockets) was assigned to the treatment group and the other half to the control group. Closed root planing was performed on the control side, and CRP plus 8.5% doxycycline gel was applied on the doxycycline-treated side. Gingival index, periodontal pocket depth, gingival crevicular fluid, and degree of attachment loss were measured at various points, revealing a mean reduction in periodontal pocket depth of 0.96 mm on the doxycycline-treated side 12 weeks after treatment application, compared with 0.62 mm on the control side (P = 0.001).13
The 2% clindamycin hydrochloride product evaluated in the present study is supplied premixed with a hydrogel, which is a thin, syrupy substance at room temperature and turns into a thick gel at body temperature. The clindamycin gel remains in the periodontal pocket for approximately 7 to 10 days, acting as a physical barrier to pocket contamination, but the gel has no anticollagenase effect. The antimicrobial effect of this product reportedly persists for up to 12 weeks.14 To the authors’ knowledge, the only reported study14 of the use of 2% clindamycin hydrochloride hydrogel to treat periodontal disease involved 48 client-owned dogs that were randomly assigned to 2 groups. The control group of 16 dogs was treated with ultrasonic dental scaling and polishing and CRP of all periodontal pockets with depths between 3 and 6 mm, and the treatment group was similarly treated with the addition of clindamycin gel application. Gingival index, periodontal pocket depths, and the number of suppurative sites were assessed before and 12 weeks after treatment, revealing an overall 19% improvement in pocket depths and gingivitis index values and an overall 64% decrease in the number of suppurative sites after treatment. Clindamycin-treated dogs had a mean reduction in periodontal pocket depth of 0.7 mm, compared with 0.1 mm in control-treated dogs.14
In human medicine, research has shown that antimicrobial treatments provide a significant mean reduction in periodontal pocket depth reduction of 0.4 mm over that achieved with CRP alone.15 However, whether the oral environment of dogs is similar enough to that of humans to allow extrapolation of this finding to dogs is unknown. Moreover, many reports16 of local antimicrobial efficacy involve studies in which no blinding was used, giving rise to speculation that true clinical benefit of local antimicrobial use may be negligible or that the effect of the local antimicrobial treatment dissipates quickly for most of the currently used compounds. Other investigators have suggested that nanoparticles of polyethylene glycol and lactic acid laced with antimicrobials can provide a sustained release and may work more effectively.17 These potential effects remain to be evaluated in dogs with periodontal disease.
The progressively worsening stages of periodontal disease in dogs are characterized by the percentage of alveolar bone loss.18 The most accurate method for estimating this bone loss requires the use of complicated subtraction radiography techniques.19,20 Analysis of periodontal pocket depth, as performed in the present study, could be considered a less reliable technique for assessing the severity of periodontal disease. For example, a small dog with a 5-mm-deep maxillary canine periodontal pocket could be expected to have more severe periodontal disease than a larger dog with a similarly sized pocket. The benefits of analyzing changes in periodontal pocket depth to monitor periodontal disease are that it is the most commonly used technique in clinical practice and is also the primary technique used to determine when treatments such as CRP and local antimicrobial application should be pursued. In addition, pocket depth has been used in several previous studies12–14 to track periodontal health. In the present study, measurements of periodontal pocket depth were made with a standard periodontal probe and rounded to the nearest 0.5 mm. It can be difficult to determine exactly where a 0.5-mm mark lies on a periodontal probe, but we believe that use of the mean of 2 technicians’ readings improved measurement accuracy, with surprisingly high precision. Small differences in changes in periodontal pocket depth may not be clinically important but, collectively, were useful to test the null hypothesis that treatment type would have no significant effect on outcome. Although the scoring system used in the present study was inherently subjective, we believe that we controlled for this subjectivity by combining the 2 sets of data from the 2 technicians.
The present study had several limitations. No placebo-treated control group was used owing to ethical concerns, given that root planing is considered the standard of care for periodontal disease in dogs. The use of research dogs instead of client-owned dogs would have eliminated the potential influence on the results of any interventions attempted at home during the 12-week follow-up period. However, we believe that the owners of participating dogs provided no such interventions during that period. Owners were advised to avoid brushing their dog's teeth and to offer softened food for 7 to 10 days following treatment, but no other attempts were made to control other types of home dental care. We decided against the split-mouth approach to treatment evaluation because many antimicrobials, including doxycycline, are known to disperse through oral fluids, potentially providing exposure of the whole mouth to the drugs.21
An important aspect of periodontal disease treatment is proper removal of the biofilm from the periodontal pockets. In our experience, careful use of both a sharp curette and ultrasonic dental scaler provides the most complete removal of plaque and calculus. One concern, particularly with local antimicrobial application, is that a practitioner may be less likely to thoroughly clean a periodontal pocket when planning to use local antimicrobial treatment because of a belief that such treatment will eliminate any residual biofilm. Although the present study was not designed to investigate whether local antimicrobial gel application can be used to treat a biofilm, such removal would be unlikely given that the glycoproteins that comprise the plaque scaffold protect the bacteria from any substantial exposure to antimicrobials.
Antimicrobial gel application to periodontal pockets in dogs may provide a longer duration of action than CRP alone, but a study with a follow-up period longer than 12 weeks would be necessary to investigate this possibility. Other than minor differences in improvement in gingivitis severity between CRP alone and CRP plus the evaluated antimicrobial gels, no significant differences were identified among treatments in dogs with periodontal pockets with a mean depth of 3.5 to 5.5 mm. We believe that these findings suggested that the added expense associated with local antimicrobial gel application may not justify its use in addition to CRP for the treatment of periodontal disease in dogs.
Acknowledgments
Supported by the American Kennel Club Canine Health Foundation (grant No. 2161-A).
The authors declare that there were no conflicts of interest.
The authors thank Christine Chevalier and Christina Marrero for performing periodontal measurements and Stephen Riback for logistical support in completing this study.
ABBREVIATIONS
| CRP | Closed root planning |
Footnotes
Hu-Friedy, Chicago, Ill.
Doxirobe, Zoetis Inc, Kalamazoo, Mich.
Clindoral, TriLogic Pharma, Montgomery, Ala.
Newtron, Acteon, Mount Laurel, NJ.
Universal Langer, Hu-Friedy, Chicago, Ill.
SAS, version 9.4, SAS Institute Inc, Cary, NC.
References
1. Lund EM, Armstrong PJ, Kirk CA, et al. Health status and population characteristics of dogs and cats examined at private veterinary practices in the United States. J Am Vet Med Assoc 1999;214:1336–1341.
2. Wiggs RB, Lobprise HB. Oral exam and diagnosis. In: Wiggs RB, Lobprise HB, eds. Veterinary dentistry principles and practice. Philadelphia: Lippincott-Raven, 1997;351–394.
3. Pavlica Z, Petelin M, Juntes P, et al. Periodontal disease burden and pathological changes in organs of dogs. J Vet Dent 2008;25:97–105.
4. DeBowes L. Problems with the gingiva. In: Niemiec BA, ed. Small animal dental, oral & maxillofacial disease: a color handbook. London: Manson Publishing Ltd, 2010;159–181.
5. Stepaniuk KS, Gingerich W. Evaluation of an osseous allograft membrane for guided tissue regeneration in the dog. J Vet Dent 2015;32:226–232.
6. Preshaw PM, Ryan ME, Giannobile WV. Host modulation agents. In: Newman MG, Takei HH, Klokkevold PR, et al, eds. Carranza's clinical periodontology. 11th ed. St Louis: WB Saunders Co, 2006;813–827.
7. Pattinson AM, Pattinson GL. Scaling and root planing. In: Newman MG, Takei HH, Klokkevold PR, et al, eds. Carranza's clinical periodontology. 11th ed. St Louis: WB Saunders Co, 2006;749–797.
8. Harvey CE. Management of periodontal disease: understanding the options. Vet Clin North Am Small Anim Pract 2005;35:819–836.
9. Beebe DE. How local antimicrobials can help manage periodontal disease. Clinician's Brief 2012;11:75–78.
10. Ryan ME. Nonsurgical approaches for the treatment of periodontal diseases. Dent Clin North Am 2005;49:611–636.
11. Wiggs RB, Lobprise HB. Periodontology. In: Wiggs RB, Lobprise HB, eds. Veterinary dentistry principles and practice. Philadelphia: Lippincott-Raven, 1997;186–231.
12. Polson AM, Southard GL, Dunn RL, et al. Periodontal pocket treatment in Beagle dogs using subgingival doxycycline from a biodegradable system. J Periodontol 1996;67:1176–1184.
13. Zetner K, Rothmueller G. Treatment of periodontal pockets with doxycycline in Beagles. Vet Ther 2002;3:441–452.
14. Johnston PJTP, Mondal P, Pal D, et al. Canine periodontal disease control using a clindamycin hydrochloride gel. J Vet Dent 2011;28:224–229.
15. Matesanz-Pérez P, García-Gargallo M, Figuero E, et al. A systematic review on the effects of local antimicrobials as adjuncts to subgingival debridement, compared with subgingival debridement alone, in the treatment of chronic periodontitis. J Clin Periodontol 2013;40:227–241.
16. Matthews D. Local antimicrobials in addition to scaling and root planing provide statistically significant but not clinically important benefit. Evid Based Dent 2013;14:87–88.
17. Lee BS, Lee CC, Wang YP, et al. Controlled-release of tetracycline and lovastatin by poly(d,l-lactide-co-glycolide acid)-chitosan nanoparticles enhances periodontal regeneration in dogs. Int J Nanomedicine 2016;11:285–297.
18. American Veterinary Dental College. Stages of periodontal disease. Available at: www.avdc.org/Nomenclature/Nomen-Perio.html#periostages. Accessed Dec 4, 2016.
19. Hausmann E. Radiographic and digital imaging in periodontal practice. J Periodontol 2000;71:497–503.
20. Corbet EF, Ho DK, Lai SM. Radiographs in periodontal disease diagnosis and management. Aust Dent J 2009;54:S27–S43.
21. Baker PJ, Evans RT, Coburn RA, et al. Tetracycline and its derivatives strongly bind to and are released from the tooth surface in active form. J Periodontol 1983;54:580–585.
Appendix
Scoring system used to grade the severity of periodontal disease in dogs (adapted from Wiggs and Loprise11).
| Score | Clinical finding |
|---|---|
| Gingival index | |
| 0 | Normal gingiva |
| 1 | Mild inflammation, slight change in color, slight edema, and no bleeding on probing |
| 2 | Moderate inflammation, redness, edema, and glazing; bleeding on probing |
| 3 | Severe inflammation |
| Plaque index | |
| 0 | No plaque |
| 1 | Thin film along gingival margin |
| 2 | Moderate accumulation and plaque in sulcus |
| 3 | Abundant soft material in sulcus |
| Calculus index | |
| 0 | No calculus |
| 1 | Supragingival calculus extending only slightly below the free gingival margin |
| 2 | Moderate amount of supragingival and subgingival calculus |
| 3 | Abundance of supragingival or subgingival calculus |
