Effective Modalities of Periodontitis Induction in Rat Model.

Induction of periodontal disease using the rat model is the preferred model for human periodontal disease studies that are related to gene expression, mechanisms of inflammatory regulation, microbial and host responses, resolution, and the healing process. There are 3 methods that are frequently used to induce periodontal disease, which are: ligature application, oral bacterial inoculation, and the lipopolysaccharide injection technique. In the ligature model, sterile non-absorbable sutures or orthodontic wires are widely used to induce local irritation and bacterial plaque accumulation. Secondly, mono and mixed cultures of periodontal bacteria are inoculated orally by gavage or topical application. Lastly, lipopolysaccharide extracted from pathogenic bacteria can be directly injected into the gingival sulcus to induce inflammation and stimulate osteoclastogenesis and alveolar bone loss. Among these methods, ligature application induces inflammation and alveolar bone resorption more promptly compared to other methods. This review will provide an overview of the main induction methods in experimental periodontal disease, with their advantages and disadvantages.

The Effect of Two Different Doses of Astaxanthin on Alveolar Bone Loss in an Experimental Model of Periodontitis in Diabetic Rats.

This study evaluated the effects of astaxanthin (ASX) on alveolar bone loss, receptor activator of nuclear factor-κB ligand (RANKL), and osteoprotegerin (OPG) activity in ligature-induced periodontitis in diabetic rats. Diabetes mellitus (DM) was induced with 50 mg/kg intraperitoneal streptozotocin in 40 male Wistar rats. The Wistar rats were divided into six experimental groups: non-ligated (NL; n = 6); ligature only (L; n = 6); DM only (D; n = 6); DM + ligature (DP; n = 6); DM + ligature + 1 mg/kg/day ASX (ASX 1 group; n = 8); and DM + ligature + astaxanthin 5 mg/kg/day ASX (ASX 5 group; n = 8). Silk ligatures were placed along the gingival margin of the left mandibular first molar tooth. The study duration was 11 days, after which the animals were euthanised. Changes in alveolar bone levels were clinically measured, and RANKL and OPG activities were immunohistochemically examined. Alveolar bone loss was the most significant in the DP group (p < 0.05). Decreased alveolar bone loss was observed in the ASX 5 group (p < 0.05). Although RANKL activity was highest in the DP group, it was observed at lower levels in the groups to which ASX was administered. OPG activity did not differ between groups (p > 0.05). The results of this study suggested that 1 and 5 mg/kg ASX administration reduced RANKL activity and alveolar bone loss in rats with experimentally induced periodontitis.

Diagnosis and Management of Furcation Lesions in Dogs - A Review.

The furcation is the anatomic area where the roots divide on a multirooted tooth. Periodontal disease causing alveolar bone loss can lead to furcation lesions of various stages. Once furcation involvement has occurred, the area can be more difficult to clean or treat due to the complex anatomy and morphology of furcations. Teeth with short root trunks, longer tooth roots, and roots with wide furcation entrance areas/degrees of separation and wide root divergence are considered better candidates for long term maintenance. Dog teeth possess many of these advantageous anatomic features compared to human teeth. Treatment options for teeth with furcation lesions include: closed debridement, open debridement, furcation plasty, tunneling, partial tooth or root resection, root separation (hemisection or trisection), regenerative therapies, or exodontia. There are many factors to consider in determining treatment options. The favorable and unfavorable characteristics for maintenance of teeth with furcation lesions are summarized. Home care and ongoing professional care are important aspects of periodontal disease control for any patient. Studies of systemic and local antibiotic therapies in human patients have not demonstrated reduction of furcation stages, and probiotic effects at furcation sites have not been specifically examined. Human review studies show that most molar teeth once deemed "hopeless" due to stage 3 furcation lesions can be maintained for at least 5 to 15 years with supportive periodontal therapy. Similar long term studies in dogs are needed to improve the evidence-based management of canine patients with furcation lesions.

Prevalence, Radiographic, and Demographic Features of Buccal Bone Expansion in Cats: A Cross-Sectional Study at a Referral Institution.

Buccal bone expansion (BBE) refers to bulbous enlargement of the periodontium in domestic cats. The origin of BBE is unknown, and some of its epidemiological, clinical, and radiographic features have not been fully characterized. The purpose of this study was to determine whether specific demographic characteristics are associated with BBE in cats; and whether BBE is associated with other relevant radiographic findings. Pertinent data were collected from archived dental radiographs and electronic medical records of 97 client-owned cats. Results showed that BBE is common in cats presented for evaluation and treatment of dental disease; that breed, sex, and age are not associated with BBE; that BBE is not associated with a pattern of horizontal alveolar bone loss/extrusion or tooth resorption; that a pattern of vertical alveolar bone loss is a typical feature of BBE; and that BBE represents a common cause of canine tooth loss in cats.

Qualitative and Quantitative Assessment of Alveolar Bone Destruction in Adult Rats Using CBCT.

Cone-beam computed tomography (CBCT) has strong potential to be utilized in various aspects of veterinary dentistry. Using ex vivo rat maxillary bone and teeth, the purpose of this study was to compare gray value, surface area, and volumetric measurements of teeth with and without experimental periodontitis by CBCT. Periodontitis was induced in 36 molar teeth, while 36 teeth with a healthy periodontium served as control. Images of each specimen along with teeth were obtained using CBCT. The following measurements for each tooth with periodontitis (n = 36) were recorded: gray value measurement, width, height, depth, surface area, and volume of the alveolar bone loss. For the control group (n = 36), gray value measurement, surface area, and volume of the alveolar bone were recorded. All measurements were repeated after 3 weeks. As the gold standard, the rat maxillas were decalcified and paraffin-embedded for further immunocytochemical study. One-way analysis of variance (ANOVA) was used. Significance level was set at P < .05. Correlation values for gray value, width, height, depth, surface area, and volume measurements were 0.983, 0.966, 0.962, 0.880, 0.998, and 0.999, respectively, for the first and second measurements. One way ANOVA showed statistically significant differences between teeth with and without alveolar bone destruction conducted for gray value, surface area, and volume measurements (P = .000). Mean gray value, surface area, and volume measurements decreased 56.46%, 81.89%, and 78.56%, respectively, for teeth with alveolar bone destruction in comparison to healthy teeth. Cone-beam computed tomography provided useful qualitative and quantitative information regarding induced periodontitis in the rat maxilla.

Humic Acid, a Polyphenolic Substance, Decreases Alveolar Bone Loss in Experimental Periodontitis in Rats.

The purpose of this study was to evaluate the biochemical, morphometric, and histopathological changes associated with experimental periodontitis in rats in response to local administration of humic acid. Thirty-eight Wistar rats were divided into 5 experimental groups: nonligated (NL) group, ligature-only (LO) group, and ligature + local administration of humic acid (20, 80, and 150 mg/kg body weight per day for 15 days, respectively; L-20, L-80, and L-150 groups). Changes in alveolar bone levels were clinically measured as the distance from the cementoenamel junction to the alveolar bone crest with a stereomicroscope. Tissues were histopathologically examined to assess the osteoclast numbers, osteoblastic activity, and inflammatory cell infiltration among the study groups. Enzyme-linked immunosorbent assay interleukin1ß (IL-1ß) and IL-10 levels in serum and gingival homogenates were evaluated. At the end of 15 days, the alveolar bone loss was significantly higher in the LO group compared to the NL, L-20, and L-150 groups (P < .05). The osteoclast number in the LO group was significantly higher than the NL, L-20, and L-150 groups (P < .05). Inflammatory cell infiltration was significantly higher in the LO and L-80 groups than the other groups (P < .05). The highest serum and gingival homogenate IL-10 levels were determined in the NL group (P < .05). The serum and gingival homogenate IL-1ß levels in LO group were significantly higher than the NL, L-20, and L-150 groups (P < .05). Within the limits of this study, it can be suggested that humic acid, when administered locally at 20 and 80 mg/kg doses, may prevent alveolar bone loss in the rat model.

Guided Tissue Regeneration Therapy With Bone Augmentation in a Lingual, Infrabony Osseous Defect of a Mandibular Canine.

This case report describes the use of canine demineralized freeze-dried membrane allograft and cancellous bone graft material to treat an infrabony osseous defect along the lingual aspect of a left mandibular canine in a 10-year-old miniature dachshund. Postoperative examination 6 and 12 months postoperatively showed osseous integration at the infrabony defect and improvement in periodontal probing measurements.

Experiment of GBR for repair of peri-implant alveolar defects in beagle dogs.

To guide barrier membrane choice in the treatment of peri-implant alveolar bone defects, we evaluated guided bone regeneration (GBR) using titanium (Ti) mesh or Bio-Gide membrane, independently or in combination, for repair of alveolar bone defects in Beagle dogs. Six months after extraction of the mandibular premolars and first molars from three beagle dogs, we inserted implants assigned into 3 groups and covered with the following membrane combinations: Group A: Implant + Bio-Oss + Ti-mesh, Group B: Implant + Bio-Oss + Bio-Gide, and Group C: Implant + Bio-Oss + Ti-mesh + Bio-Gide. At 6 months, micro-CT revealed that bone volume/total volume (BV/TV), trabecular number (Tb.N), and trabecular thickness (Tb.Th) was significantly greater in Group C than the other two groups, while trabecular separation (Tb.Sp) was significantly lower, suggesting improved bone regeneration. The distance between bands of three fluorescent tracking dyes was significantly greater in Group C, indicating faster deposition of new bone. The Bio-Oss particles were ideally integrated with newly deposited bone and bone thickness was significantly larger in Group C. These findings suggest that combination of Bio-Gide membrane and titanium mesh can effectively repair peri-implant alveolar bone defects, achieving enhanced bone regeneration compared to titanium mesh or Bio-Gide alone, and therefore providing a novel treatment concept for clinical implant surgery.

Diagnostic imaging of oronasal fistulas in a dachshund.

Oronasal fistula development is described anecdotally as a common disease process in the dachshund but little is known about its imaging appearance. This case report describes the clinical presentation, computed tomography (CT) characterisation, dental radiograph confirmation and treatment of bilateral oronasal fistulas in a 14-year-old dachshund.

Dental Implants and Incisor Bridge Placement in a Dog.

Veterinary dentistry has tended to follow the trends and advancements in the human dental field. As for any procedure performed on a patient, whether human or animal, an informed decision is based on the available evidence regarding treatment options. This is certainly true for the more involved treatments in veterinary dentistry which can include the disciplines of endodontics and dental implantology. A number of published case reports have been accepted by the specialty that endodontic therapy is indeed a predictable and a valuable service that can be offered to pet owners. Oral implantology has become an accepted and predictable procedure in the human dental field and can now be offered to pet owners if performed by suitable trained veterinary clinicians. The success rate for endosseous implant osseointegration is very high in humans. Success rates are also very high in animals used for implantology research. Canine studies have shown good bone-to-implant contact of around 73% in osseointegrated endosseous implants based on histological sections. Radiographic and histological findings demonstrate stable alveolar crestal bone levels after loading endosseous implants for up to 12 months in a dog model. This article discusses use of dental implants in the rostral mandible of a companion dog to replace periodontally diseased incisors, their restoration, to return the animal to full dental function and 3-year follow-up.

A modified method for inducing periodontitis in dogs using a silk-wire twisted ligature.

This study was designed to assess the effectiveness of a modified silk ligature twisted with wire for inducing advanced periodontitis. Periodontitis was induced in five premolars and one molar of 20 healthy dogs over a 60-day period. The dogs were divided into four groups according to the ligature-inducing materials used: soft moistened food only, wire ligature (WL), silk ligature (SL) and twisted ligature with silk and wire (SWL). Periodontal indices were recorded, and dental radiographs were taken before and after 60 days of ligation. The ligatures were checked daily and the day the ligature fell out was noted. The period during which the ligatures were maintained was significantly shorter for the SL group compared to the SWL group (p < 0.05). Results of the clinical examination showed that almost all periodontal status parameters including the plaque index, gingival index, clinical attachment level, and bleeding on probing were significantly exacerbated in the SWL group compared to the other groups (p < 0.05). Radiographic evaluation demonstrated that alveolar bone levels were significantly lower in the SWL group than the other groups on day 60 (p < 0.05). These results suggested that experimental periodontitis induced by SWL could be an effective method for investigating periodontitis in canine models.

The development of an oral health charting system for koalas (Phascolarctos cinereus).

The koala is one of Australia's most highly specialized folivores with a diet exclusively of eucalyptus leaves to provide all nutritive needs and therefore requires to be free of oral disease as they are dependent on good dentition for optimal health and quality of life. We developed an oral examination methodology based on protocols for companion animals and human dentistry to chart the oral health of koalas. Thirty free-ranging koalas from South-East Queensland, Australia were examined for general body and oral health. Inspection of the oral cavity was conducted for the presence or absence of the indicators oforal disease such as caries or periodontal disease. Univariate and multivariate analyses were performed on the examination data and a prototype oral health chart developed. The prototype was then trialled and the methodology validated by the Kappa statistic using ten additional koalas examined by four multidisciplinary personnel involved in koala care. Trauma associated fractures, tooth displacement, abnormal occlusion and tooth wear compacted vegetation, extrinsic stain deposits, periodontal bone loss, gingivitis, tooth mobility, and calculus were present in the oral cavities of the examined koalas. A system of scoring between 0 and 3 was constructed in accordance with current koala general health charting formats. Validation of the charting method using Kappa coefficients of agreement statistics indicated that there was a good agreement among observers on recorded results except for inflammation and calculus scoring. Modifications were made and visual aids and index scales produced to further assist observers. Oral health surveillance has been proven in other species to be significant in diagnosing physiological disturbances derived from environmental genetic, and developmental causes. Veterinarians, dental researchers, and koala husbandry personnel will benefit in using this charting method and reporting the oral health of koala populations in their future findings. This unique form of oral health monitoring would be adaptable to other mammals.

Bilateral dentigerous cysts in a dog.

Dentigerous cysts are infrequently seen in veterinary medicine, but the consequences of an undiagnosed dentigerous cyst can be severe. Dentigerous cysts, that can be sub-classified as eruption or follicular, are a type of benign odontogenic cyst. They can cause significant bony and dental destruction associated with expansion if they remain undiagnosed for a period of time. Dentigerous cysts are secondary to embedded or impacted teeth, however not every impacted tooth subsequently forms a dentigerous cyst. Intraoral dental radiographs are necessary to differentiate a missing tooth from an impacted tooth. This case demonstrates the successful surgical management of a dog with bilateral impacted mandibular canine teeth, with secondary dentigerous cyst formation.

Periodontal health status in a colony of 109 cats.

Periodontal disease has not been well characterized in the cat, and it is not known if feline tooth resorptions (TR) are equivalent to those observed in humans and dogs. The aim of this study was to investigate the different patterns of periodontal inflammation in cats, and to evaluate their prevalence in a standardized healthy population (n = 109). Particular emphasis was placed on the potential associations between TR and periodontal parameters, as well as the influence of potential risk factors (including breed, sex, and age). A single complete periodontal examination was performed, including periodontal probing of each tooth and exploration of the tooth surface using a dental explorer; at least 10 radiographs were taken for each cat. Missing teeth with radiographic evidence of root apices were present in 34.0% of cats. Periodontal disease was common, and 13.0% of cats had aggressive periodontitis. All of the cats had some form of periodontal inflammation, and only 4.0% of cats were free from gingival inflammation. Moderate to severe gingivitis was present in 13.0% of teeth. Dental furcation exposure was present in 18.0% of all multi-rooted teeth. Periodontal bone loss was observed in 31.2% of teeth, with the majority (98.2%) of all cats having some form of periodontal bone loss. Breed effects were identified for some variables. Eight of 14 periodontal variables were statistically correlated with Type 1 TR. Two of 14 variables (and age) were statistically correlated with Type 2 TR. In conclusion, the cats of this colony had a wide range of periodontal inflammation, including aggressive periodontitis. Type 1 TR and Type 2 TR were identified to be two significantly different manifestations of TR, with a strong association between Type 1 TR and periodontal disease.

Oral examination and radiographic evaluation of the dentition in wild cats from Namibia.

Feline tooth resorption has been widely reported in domestic cats and sporadically described in other felidae. The goal of the present study was to determine the prevalence of tooth resorption and to report other dental problems in a population of wild felidae. Observations of dental disorders and anomalies were made in skulls from 73 wild felidae (cheetahs, leopards, caracals, African wildcats, and lions) originating from Namibia. In addition, radiographs were taken in 43 cases to determine signs of bone and root pathology. Radiographs showed varying stages of tooth resorption in 16.0% of the specimens. Other dental anomalies found included fused teeth, supernumerary roots, or missing teeth. The prevalence of dental resorption in wild felidae was lower than reported in the domestic cat.