Dentistry overview
Small Animal Dentistry James Fairs BVSc MSc MRCVS
jfairs@rossvet.edu.kn
Dentistry Course Overview
Importance of Small Animal Dentistry and Education: This section covers the foundational reasons why veterinary professionals must prioritize and understand small animal oral health, including its significant impact on overall patient well-being and clinical practice.
Oral Anatomy and Nomenclature: A comprehensive study of the structures within the oral cavity and the standardized terminology used to describe them, which is crucial for accurate diagnosis, communication, and treatment planning.
Oral Examination and Radiology: Detailed procedures for thorough clinical examination of the oral cavity and interpretation of dental radiographs, essential tools for identifying pathologies often hidden below the gum line.
Developmental Abnormalities: Exploration of congenital or developmental issues affecting tooth and oral structure formation, such as retained deciduous teeth, malocclusions, and missing teeth.
Diseases of Hard Tissues: Focus on conditions affecting enamel, dentin, and cementum, including fractures, attrition, and pulp exposure.
Periodontal Disease - Staging: Classification of periodontal disease severity (e.g., PD0 to PD4) based on clinical and radiographic findings.
Charting: Systematic documentation of all oral findings, including missing teeth, periodontal pockets, and lesions, using standardized dental charts.
Treatment: Therapeutic interventions for periodontal disease, ranging from professional dental cleaning (prophylaxis) to advanced surgical procedures like extractions andGuided Tissue Regeneration (GTR).
Prevention: Strategies and recommendations for clients to maintain optimal oral health in their pets, reducing the incidence and progression of dental disease.
Overview Continued
What does small animal dentistry mean in general practice?: This addresses the practical application of dental knowledge in a typical veterinary clinic, emphasizing routine check-ups, preventive measures, and common treatments.
Reconsideration of the term ‘a dental’: Encourages a shift from simply calling a professional oral care procedure “a dental” to understanding it as a comprehensive approach involving examination, diagnosis, treatment, and follow-up, often requiring anesthesia.
Client communication: Focuses on effective strategies for educating pet owners about the importance of dental health, explaining findings, treatment plans, and home care instructions.
Role of Referrals to Specialists: Discusses when and why a general practitioner should refer complex dental cases, such as advanced periodontal surgery, orthodontics, or intricate restorative procedures, to a board-certified veterinary dentist.
Resources: Identification of essential dental instruments, educational materials, and professional organizations (e.g., AVDC, AVD) that support veterinary dental practice and ongoing education.
7th Semester: Specifies the academic period or curriculum point at which this subject matter is typically covered in a veterinary program.
Why is Small Animal Dentistry Important?
Importance of Small Animal Dentistry
Periodontitis is the most commonly diagnosed disease in small animal veterinary medicine (Niemiec, 2008), underscoring its widespread impact on pet health. This inflammatory condition affects the supporting structures of the teeth.
Affects >87% of dogs older than 2 years (Wiggs & Lobprise, 1997), indicating a prevalent health issue that often goes unnoticed by owners.
98% of Yorkshire Terriers have at least one tooth or aspect with early periodontitis by 37 weeks old, highlighting breed-specific predispositions and the early onset of disease in some cases.
Up to 75% of adult cats are affected by oral resorptive lesions, a painful condition where the tooth structure is progressively destroyed, often requiring extraction.
Clinical signs of periodontal disease can range from mild (e.g., halitosis, mild gingivitis) to severe (e.g., gum recession, tooth mobility, oral pain, difficulty eating), and can be very painful, significantly impacting the animal's quality of life.
The effects of periodontal disease are not limited to the oral cavity, as the bacteria present in diseased gums can lead to a hematogenous spread (spread via the bloodstream) throughout the body, potentially affecting distant organs such as the heart, kidneys, and liver, exacerbating systemic diseases.
Importance: Continued
Periodontitis is not the only dental disease; other conditions like tooth fractures, dental caries (cavities), malocclusions, and oral tumors also significantly impact pet health and welfare.
It has a huge impact on general health & welfare, directly affecting an animal's ability to eat, play, and live without chronic pain, which can lead to behavioral changes and a reduced lifespan.
Role of the General Practitioner: This role is multifaceted and critical:
Welfare: To alleviate pain and improve the overall quality of life for pets suffering from dental disease.
Prevention/Prophylaxis: To advise on and implement strategies for preventing dental disease (e.g., regular brushing, dental diets, professional cleanings).
Education: To inform and empower pet owners about the importance of oral health and home care.
Salvage: To preserve as many healthy teeth as possible through appropriate treatments, while also knowing when extraction is the best course of action.
Very common procedures in general practice and a significant source of revenue, as dental services are frequently needed and can involve both preventive and complex treatments.
33% of practices in the US derive up to 5% of annual revenue from dental care, underscoring the economic significance of providing comprehensive veterinary dental services.
The global pet oral care products market is thought to be around 2 billion, indicating a substantial industry dedicated to maintaining pet oral hygiene, from toothpastes and brushes to specialized dental chews and diets.
Small Animal Dentistry: Anatomy & Nomenclature
James Fairs BVSc MRCVS
jfairs@rossvet.edu.kn
Anatomy & Nomenclature: Learning Objectives
Understand and explain normal dental anatomy, including the structure of teeth (crown, root, enamel, dentin, pulp, cementum) and surrounding periodontium, to recognize healthy oral structures.
Describe tooth development, eruption process, and eruption schedule, detailing how teeth form from tooth buds, emerge through the gingiva, and the typical timelines for deciduous and permanent teeth in dogs and cats.
Differentiate between successive and non-successive teeth, understanding which permanent teeth replace deciduous ones and which erupt without predecessors.
Understand and utilize appropriate oro-dental nomenclature, including anatomical (e.g., buccal, lingual, mesial, distal) and modified Triadan systems, for precise communication and accurate medical record-keeping.
Skull Anatomy
Orbit: (O) The bony cavity that houses the eyeball and associated structures.
Temporomandibular Joint: (TMJ) The hinge joint connecting the mandible to the temporal bone of the skull, crucial for jaw movement.
Nasal Cavity: (NC) The large air-filled space above and behind the nose.
Maxilla: (Mx) The paired bone forming the upper jaw, roof of the mouth, and floor of the orbits.
Mandible: (Md) The lower jawbone, forming the lower part of the oral cavity.
Infraorbital Foramen: (IF) An opening below the orbit in the maxilla, through which nerves and blood vessels pass to supply the upper lip and nose.
Mental Foramina: (MF) Openings on the external surface of the mandible, allowing passage of nerves and blood vessels to the lower lip.
Dental Anatomy: Crown
Crown: The visible portion of the tooth above the gum line, comprising 30-40% of the tooth's total length. It's the functional part that interacts with food and opposing teeth.
Enamel: The hardest tissue in the body, mineralized (hydroxyapatite crystals), appearing white and smooth. It covers the crown, protecting the underlying dentin. Its hardness makes it resistant to wear but also brittle.
Regeneration/Repair: None. Once adult enamel is damaged, it cannot regenerate or repair naturally, making its protection paramount.
Dentin: A dense, porous, calcified tissue that forms the bulk of the tooth, underlying the enamel and cementum. It provides elasticity and support to the enamel and surrounds the pulp cavity.
Regenerative throughout its life. Odontoblasts within the pulp can produce secondary and tertiary (reparative) dentin in response to wear or injury, providing some protective capacity.
Pulp: The innermost part of the tooth, located within the pulp cavity. It contains nerves (providing sensitivity and pain perception), vascular supply (bringing nutrients), lymphatics, and connective tissue. It is responsible for dentine production by odontoblasts and generally thins with age as secondary dentin is continually laid down.
Dental Anatomy: Root
Comprises 60-70% of the tooth and is embedded within the alveolar bone. The root's health is intrinsically associated with most tooth pathologies, particularly periodontal disease.
Dentin: Forms the core structure of the root, just as in the crown, but it is covered by cementum rather than enamel.
Cementum & Cemento-enamel Junction (CEJ): Cementum is a bone-like connective tissue covering the dentin of the root. The CEJ is the anatomical line where the enamel of the crown and the cementum of the root meet, a critical landmark for assessing periodontal health.
Apex: The very tip of the root, which communicates with the external environment via microscopic openings. The apex closes around 8 months in cats and dogs, up to 12 months max; this closure signifies the completion of root development and thickening of dentinal walls. It forms the apical delta with 10-20 microscopic ramifications, through which the neurovascular supply enters the pulp cavity.
Lateral Canals: Small accessory canals branching off the main pulp canal, typically low prevalence in cats & dogs, but significant for endodontics as they can be pathways for infection from periodontal disease to the pulp, and vice-versa.
Alveolus: Refers to the bony socket within the maxilla or mandible that houses the root of the tooth, providing structural support and attachment for the periodontal ligament.
Dental Anatomy: Periodontium
The supporting structure of the tooth, comprising 4 components that secure the tooth in the jaw and absorb masticatory forces:
Gingiva: The gums, composed of mucosal tissue, which surround the teeth and cover the alveolar bone. It acts as a protective barrier.
Cementum: A specialized, avascular, and mineralized connective tissue that covers the root surface, attaching the tooth to the alveolar bone via the periodontal ligament. It thickens with age and continues to form throughout the animal's life.
Alveolar Bone: The part of the jaw bone (maxilla or mandible) that forms the socket (alveolus) for the teeth. It provides rigid support for the tooth roots.
Periodontal Ligament: (PDL) A fibrous connective tissue bundle of collagen fibers (Sharpey's fibers) that serves as the strong but elastic attachment between the cementum of the tooth root and the alveolar bone of the socket. It functions as a shock-absorbing system during chewing, distributes occlusal forces, and contains nerves that provide proprioception. It appears radiolucent in X-rays due to its soft tissue composition.
Dental Anatomy: Soft Tissues
Oral Mucosa: The moist lining of the oral cavity, which is generally thinner and less keratinized than skin, providing a protective and secretory surface.
Gingiva (G): The specialized part of the oral mucosa that covers the alveolar process of the jaws and tightly surrounds the neck of the teeth, acting as a critical barrier against bacterial invasion.
Attached Gingiva: The part of the gingiva that is firmly and tightly attached to the underlying alveolar bone and tooth cementum via Sharpey's fibers. It is typically resilient and stippled.
Free Gingiva: The unattached, knife-edged margin of the gingiva that surrounds the tooth, creating a shallow space known as the gingival sulcus between itself and the tooth surface.
Mucogingival Junction (MGJ): The scalloped line or demarcation point separating the pink, firm, keratinized attached gingiva from the redder, looser, and more elastic alveolar mucosa. It is easily seen in dogs but often harder to identify definitively in cats.
Alveolar Mucosa (AM): The pliable, somewhat loose, and stretchable tissue that covers the bone beyond the attached gingiva, allowing for jaw movement and stretching of the oral cavity.
Radiographic Dental Anatomy
Visual components visible in radiographic images are crucial for diagnostic interpretation:
Pulp (P): Appears radiolucent (dark) due to its soft tissue and non-mineralized nature, providing a visible outline of the pulp cavity within the crown and root.
Dentin (D): Appears radiopaque (gray-white) as it is mineralized, forming the main bulk of the tooth structure around the pulp.
Enamel (E): The most radiopaque (bright white) structure on a radiograph, covering the crown, due to its extremely high mineralization.
Periodontal Ligament (PL): Appears as a thin, radiolucent line surrounding the darker root, representing the space occupied by the soft periodontal ligament fibers.
Alveolar Bone (AB): Appears radiopaque, forming the bony socket around the tooth. Its density and integrity are important indicators of periodontal health.
Cortical Bone (CB): The dense outer layer of bone that appears as a more radiopaque line, typically seen as the lamina dura lining the alveolus.
Cementum: Typically not visible as a distinct layer on radiographs due to its similar radiopacity to dentin and its relatively thin nature, but its health is inferred by the integrity of the periodontal ligament space and alveolar bone.
Oral Nomenclature
Special terminology unique to oral nomenclature is required to accurately describe abnormal anatomy and pathology locations within the oral cavity, ensuring clear and consistent communication among veterinary professionals.
Quadrants of the Mouth: The oral cavity is divided into four sections for ease of identification and charting:
Maxillary Left & Right (Upper Jaw)
Mandibular Left & Right (Lower Jaw)
Oral Nomenclature Continued
Terminology Definitions: These terms are essential for precise localization of dental findings:
Labial: The aspect of the tooth or oral structure facing the lips, typically referring to incisors and canines.
Buccal: The aspect of the tooth (premolars and molars) or oral structure facing the cheeks.
Palatal: The aspect of maxillary teeth or structures facing towards the palate (roof of the mouth).
Lingual: The aspect of mandibular teeth or structures facing towards the tongue.
Mesial: The aspect of the tooth facing the adjacent tooth towards the midline of the dental arch. For incisors, this means closer to the center of the mouth.
Distal: The aspect of the tooth facing the adjacent tooth away from the midline of the dental arch. For the last tooth in the arch, this is the caudal-most surface.
Occlusal: The chewing surface or aspect of the tooth (molars and premolars) that makes contact with the opposing jaw's teeth during mastication.
Coronal: Towards the crown of the tooth or closer to the biting/chewing surface. Used to describe the direction or location of a feature (e.g., coronal pulp exposure).
Apical: Towards the apex (tip) of the root or further into the alveolar bone. Used to describe the direction or location of a feature (e.g., apical abscess).
Additional Abbreviations
Labial (La)
Buccal (B)
Palatal (P)
Lingual (Li)
Mesial (M)
Distal (D)
Occlusal (O)
Tooth Function
Carnivorous Dental Adaptations: The dentition of dogs and cats has evolved to suit their predatory and carnivorous diets, with different tooth types specialized for specific functions in acquiring and processing food.
Incisors (I): Small, single-rooted teeth located at the front of the mouth, primarily used for nibbling, grooming, and delicately grasping objects.
Canines (C): Long, single-rooted, pointed teeth, one set in each quadrant, specifically adapted for tearing, catching, and holding prey, as well as defense.
Pre-molars (PM): Located behind the canines, these teeth vary in size and shape but are generally used for crushing and grinding/chewing food into smaller pieces. They can have one, two, or three roots depending on their position.
Molars (M): Located at the back of the mouth, these teeth are larger and have broader occlusal surfaces, primarily for heavy crushing, grinding, and chewing the toughest parts of food. They typically have multiple roots.
Carnassials: A specialized pair of teeth unique to carnivores, consisting of the last upper premolar (PM4) and the first lower molar (M1). These teeth are adapted with sharp, shearing blades for sectioning and cutting larger pieces of meat and bone, functioning like scissors.
Tooth Functional Diversity
Teeth can possess 1, 2, or 3 roots, a characteristic that varies depending on the tooth type and its position in the jaw, reflecting the different mechanical forces they endure.
Single-rooted teeth generally possess longer roots than 2- or 3-rooted teeth to enhance strength and provide adequate anchorage against occlusal forces, especially in canines and incisors that experience significant pulling or gnawing forces.
Roots are typically longer than crowns and vary in size and number relative to the teeth's functions and the need for stability within the alveolar bone.
Tooth Eruption
For dogs and cats, deciduous (baby) teeth fully erupt between 2-3 months after birth, establishing a temporary dentition for early feeding.
Not all permanent teeth have accompanying deciduous teeth:
Successional Teeth: These are permanent teeth that develop beneath and eventually replace deciduous predecessors. Most canine and feline incisors, canines, and some premolars fall into this category.
Non-successional Teeth: These are permanent teeth that erupt without deciduous predecessors. In both cats and dogs, all molars and the first premolars in dogs are examples of non-successional teeth.
Deciduous Teeth Characteristics
Deciduous teeth are:
Smaller and whiter than permanent teeth, reflecting their temporary nature and less dense mineralization.
Have relatively longer and more fragile roots than permanent teeth, which are designed for natural resorption as the permanent teeth develop beneath them.
Feature wider pulp cavities, making them more susceptible to pulp exposure and infection if fractured.
Permanent Tooth Eruption
All permanent teeth typically erupt lingually or palatally (towards the tongue or palate) to the corresponding deciduous teeth, guiding their path. This natural eruption pattern helps ensure proper alignment.
Exception: maxillary canine teeth, which erupt mesially (towards the midline) to their deciduous predecessors.
Retained Deciduous Teeth: The presence of deciduous teeth persisting in the mouth beyond their normal exfoliation time, alongside their permanent counterparts, is a common developmental abnormality. This condition illustrates the eruption pattern, as the permanent tooth often emerges next to the retained deciduous tooth, leading to crowding and potential malocclusion.
Tooth Eruption Schedule: Dog
Incisors:
Deciduous: 3-4 weeks
Permanent: 3-5 months
Canines:
Deciduous: 3-5 weeks
Permanent: 4-6 months
Premolars:
Deciduous: 4-6 weeks
Permanent: 4-6 months
Molars:
No deciduous set
Permanent: 5-7 months
Tooth Eruption Schedule: Cat
Incisors:
Deciduous: 2-3 weeks
Permanent: 3-4 months
Canines:
Deciduous: 3-4 weeks
Permanent: 4-5 months
Premolars:
Deciduous: 3-6 weeks
Permanent: 4-6 months
Molars:
No deciduous set
Permanent: 4-6 months
Tooth Eruption Influencing Factors
Eruption timing can be influenced by several factors, leading to variations from the standard schedules:
Sex: Females generally erupt teeth earlier than males, though this difference is often subtle.
Size: Larger breeds tend to erupt their permanent teeth earlier than smaller breeds, related to their faster overall growth rate.
Nutritional Status: Poorer nutrition or systemic illness can delay eruption, as adequate nutrients are essential for proper tooth development and emergence.
Permanent Tooth Maturation
As permanent teeth mature after eruption, several important changes occur:
Pulp cavity narrows due to continuous deposition of secondary dentin by odontoblasts throughout the tooth's life.
Dentin thickens, providing increased structural integrity and protection for the pulp.
Apex closes (by 12 months), completing the formation of the root and ensuring a fully developed connection for the neurovascular supply. Before apical closure, the pulp is more vulnerable to infection.
This maturation phase is critical for interpreting dental radiographs, as the appearance of the pulp cavity and apical region differs significantly between immature (wide pulp, open apex) and mature (narrow pulp, closed apex) teeth, informing treatment decisions.
Images illustrate the differences between immature (e.g., wide pulp chamber, open apex, thin dentin walls) and mature canine teeth (e.g., narrow pulp canal, closed apex, thick dentin walls), which is important for prognostication and treatment planning, especially in cases of dental trauma.
Anatomical Dental Formula: Dog
These formulas represent the number of incisors (I), canines (C), premolars (PM), and molars (M) in one half of the upper jaw and one half of the lower jaw, multiplied by 2 for the full mouth.
Deciduous: 2 (I 3/3, C 1/1, PM 3/3) = 28 teeth total.
This means: 3 upper incisors, 3 lower incisors; 1 upper canine, 1 lower canine; 3 upper premolars, 3 lower premolars per half mouth.
Permanent: 2 (I 3/3, C 1/1, PM 4/4, M 2/3) = 42 teeth total.
This means: 3 upper incisors, 3 lower incisors; 1 upper canine, 1 lower canine; 4 upper premolars, 4 lower premolars; 2 upper molars, 3 lower molars per half mouth.
Anatomical Dental Formula: Cat
Deciduous: 2 (I 3/3, C 1/1, PM 3/2) = 26 teeth total.
This means: 3 upper incisors, 3 lower incisors; 1 upper canine, 1 lower canine; 3 upper premolars, 2 lower premolars per half mouth.
Permanent: 2 (I 3/3, C 1/1, PM 3/2, M 1/1) = 30 teeth total.
This means: 3 upper incisors, 3 lower incisors; 1 upper canine, 1 lower canine; 3 upper premolars, 2 lower premolars; 1 upper molar, 1 lower molar per half mouth.
Canine Dental Structure
Canines: The intricate structure of permanent teeth, including the number of roots, varies significantly to accommodate their diverse functions and positions in the jaw.
For example:
Incisors: Typically have one root, well-suited for their lighter functions of nibbling and grooming.
Canine: Usually possess a single, very long, robust root, which provides exceptional anchorage for tearing and holding.
Premolars: The number of roots varies from 1 to 3 depending on their position. Anterior premolars might be single-rooted, while posterior premolars often have 2 or 3 roots to support their crushing function.
Molars: Typically more complex with multiple roots (2 or 3), providing maximum stability for heavy grinding and crushing forces at the back of the mouth.
Modified Triadan System
The accepted standard for dental nomenclature in veterinary dentistry globally, providing a concise and unambiguous way to identify specific teeth. It is essential for accurate charting and documenting abnormal anatomy, pathology locations, and treatment plans in medical records.
Uses three-digit numbers only, ensuring consistency and clarity across different veterinary practices.
Modified Triadan System Quadrants
The first digit denotes the specific quadrant in the mouth, assigning a unique identifier to each section:
Upper Right Maxillary: 1 (for permanent teeth)
Upper Left Maxillary: 2 (for permanent teeth)
Lower Left Mandibular: 3 (for permanent teeth)
Lower Right Mandibular: 4 (for permanent teeth)
For deciduous teeth, the quadrants are numbered consecutively from 5 to 8:
Upper Right Deciduous Maxillary: 5
Upper Left Deciduous Maxillary: 6
Lower Left Deciduous Mandibular: 7
Lower Right Deciduous Mandibular: 8
The following two digits (01-11) denote the specific tooth within that quadrant, numbered sequentially from the most mesial incisors (01) towards the most caudal molars. This universal numbering ensures every tooth can be precisely identified.
For example (Permanent Teeth):
Upper Right: 101 (first incisor), 102, 103, 104 (canine), 105…, 110 (last molar)
Upper Left: 201, 202, 203, 204…, 210
Lower Left: 301, 302, 303, 304…, 311
Lower Right: 401, 402, 403, 404…, 411
Modified Triadan System Nuances
Tips for Use: Understanding these common patterns simplifies the application of the Triadan system:
Canine teeth always end in ‘04’ in their respective quadrant (e.g., 104, 204, 304, 404). This is a reliable landmark.
First molars in dogs usually end in ‘09’ (e.g., 109, 209, 309, 409). In cats, the upper first molar is 109/209, but there is only one lower molar, 309/409.
The numbering is continuous from mesial to distal, even if teeth are absent. The number represents the position in the full dental arch.
Species Differences in the Triadan System
Cats have fewer teeth than dogs in their permanent dentition (30 vs. 42 teeth), but the Triadan numbering system remains consistent; the missing teeth are simply accounted for by skipping their numbers, counted as if they would be present in a complete carnivore dentition.
Missing teeth (non-successional/congenitally absent) in cats include:
1st upper PMs: 105, 205 (often congenitally absent in cats)
1st & 2nd lower PMs: 305, 306, 405, 406 (often congenitally absent in cats)
Cat’s numbering structure therefore skips these numbers, providing a unique sequence:
Upper jaw permanent teeth: 101, 102, 103, 104, 106, 107, 108, 109 (missing 105).
Lower jaw permanent teeth: 301, 302, 303, 304, 307, 308, 309 (missing 305, 306).
Canine Triadan Formula
This formula illustrates the relationships and systematic numbering of canine permanent teeth according to the Triadan system.
Upper Right (Maxillary): 101, 102, 103 (Incisors), 104 (Canine), 105, 106, 107, 108 (Premolars), 109, 110 (Molars)
Upper Left (Maxillary): 201, 202, 203 (Incisors), 204 (Canine), 205, 206, 207, 208 (Premolars), 209, 210 (Molars)
Lower Left (Mandibular): 301, 302, 303 (Incisors), 304 (Canine), 305, 306, 307, 308 (Premolars), 309, 310, 311 (Molars)
Lower Right (Mandibular): 401, 402, 403 (Incisors), 404 (Canine), 405, 406, 407, 408 (Premolars), 409, 410, 411 (Molars)
Feline Triadan Formula
This formula details the structure of feline permanent teeth, explicitly showing the absent teeth while maintaining the consistent numbering of the Triadan system.
Upper Right (Maxillary): 101, 102, 103 (Incisors), 104 (Canine), (105 - absent), 106, 107, 108 (Premolars), 109 (Molar)
Upper Left (Maxillary): 201, 202, 203 (Incisors), 204 (Canine), (205 - absent), 206, 207, 208 (Premolars), 209 (Molar)
Lower Left (Mandibular): 301, 302, 303 (Incisors), 304 (Canine), (305, 306 - absent), 307, 308 (Premolars), 309 (Molar)
Lower Right (Mandibular): 401, 402, 403 (Incisors), 404 (Canine), (405, 406 - absent), 407, 408 (Premolars), 409 (Molar)