Essentials for Primary Dental Care Cleet Griffin, DVM, DABVP, DAVDC/Eq Dept. of Large Animal Clinical Sciences Texas A&M University INTRODUCTION Veterinarians performing oral examinations and primary dental care should have up-to-date equipment available, including a dental speculum and bright source of light. A dental mirror or oral endoscope is necessary in order to closely examine the cheek teeth and associated oral soft tissues. INSTRUMENTATION Basic requirements

• Veterinarians should possess the proper dental instruments in order to perform an oral examination and corrective procedures in a safe and efficient manner

• Improper use of dental floating instruments may potentially damage the horse’s teeth, gums, cheeks and tongue

• A full mouth dental speculum is essential for performing a detailed examination and precise corrective procedures

• A bright source of light is very important for optimal visualization of the oral cavity • The sedated horse’s head should be supported in a comfortable position for dental procedures by

using an adjustable head stand or dental halter Oral Irrigation Equipment

• Large dose syringes are used to rinse the mouth and are available with either a pistol grip or in a plunger style

• The patient’s mouth should be rinsed before the intra-oral portion of the dental examination in order to facilitate proper visualization of the teeth and associated soft tissues

• The rounded blunt end of the nozzle on the large nylon dose syringes helps prevent accidental oral injury during flushing

• The addition of 10-20 mls of chlorhexidine gluconate 2% solution per gallon of water creates a useful oral rinse solution for horses and will prevent fogging of the dental mirror

• A high flow pressure pump attached to a hose and spray handle with right angle tip is very useful for removal of debris from the interproximal spaces of the cheek teeth

Dental Speculum A dental speculum is utilized to visually and manually evaluate the mouth, and several configurations are readily available. These instruments work via insertion into the mouth between the upper and lower incisors teeth or within the interdental space. Two types of specula are needed:

• a full mouth speculum is recommended for cheek teeth examination and procedures • one-sided metal gags inserted between the cheek teeth are not recommended because they may

fracture a tooth or lacerate the major palatine artery.

Fig. 1. Pump unit, hoses and spray handle used by the author for irrigation of the oral cavity.

Full mouth specula A full mouth dental speculum is absolutely essential for performing both complete, detailed dental examinations and precise corrective procedures (Fig 2). All specula can deliver serious injury if the horse swings its head

unexpectedly. For safety, it is a good idea for the examiner and assistant to keep a hand on the speculum as a brace in the event the horse lunges or swings the head. Everyone in the work area must be continuously aware of the horse’s attitude. Owners or any other personnel not directly involved with the procedures should be at a safe distance away.

• All full mouth specula work on the same principle: plates inserted on the incisor occlusal surfaces hold the mouth open by ratchets, screws, locking pins or friction clamps

• There are three basic categories of full mouth specula: • ratchet speculum • compound-action, hinged-type speculum • screw-type speculum

Fig. 2. Ratchet speculum (left); compound action-hinged speculum (center); screw-type speculum (right).

Light sources

• Dim or poorly designed lights create frustration and difficulty for the examiner. Any practitioner performing primary dental care procedures in horses should have a bright light source.

• Durability, comfort, and ease of use are very important considerations. With DC powered lights, extra batteries should be available, especially when working in an ambulatory setting. It is a good idea to have a backup light source available in case the primary light source fails during a procedure.

• Basic categories of light sources for equine dentistry include: o Headlamps (Fig. 3) o Battery-powered speculum lights (Fig. 4)

Fig. 3. Examples of battery powered headlamp for dentistry

Fig. 4. Magnetic light Special Equine Dental Instruments

• Dental mirrors are readily available and are necessary for closer inspection of the gums and cheek teeth in horses (Fig 5)

• Periodontal probe - necessary to measure the depth of pockets in the gum and exploring suspicious areas around the tooth (Fig 6)

• Dental explorer - necessary to confirm the presence exposed pulp (Fig 6) • Cheek retractors can be useful for improving visualization by pulling/pushing the cheeks and tongue

slightly away from the adjacent teeth.

Fig. 5. The dental mirror is being used to better visualize the lower cheek teeth and periodontal tissues.

Fig. 6. Periodontal probe (top) and dental explorer (bottom)

Canine Tooth Instruments • Nippers and cutters should not be used on canine teeth. Fracturing the tooth or opening the pulp or dentinal tubules can lead to pain, pulpitis and tooth death • To avoid over reduction of the canines, small files or diamond disc grinders (at low speed) should be used only for blunting the most coronal aspect of a sharp canine tooth • Calculus accumulation can usually be removed without difficulty using small forceps or a dental scaler

Head Stands and Dental Suspension Halters

• Dental head supports and head stands vary in cost and complexity and come in many styles (Fig. 7) • Manufactured head stands have several advantages that include rapid adjustment of height, good

stability, and often, heavy padding as well as a washable cover on which the mandibles can rest. • There are a variety of manufactured, rigid dental halters available that work very well - a single rope

placed over the noseband of the halter with a quick release device is very convenient method to adjust the height of the horse’s head

Fig. 7. Adjustable head rest (left); dental halter (right) Dental Charting

• A medical record of the findings should be accomplished using a pictorial graph of the patient’s mouth. (Fig. 8)

• The front side of the chart should contain the information obtained on the exam. The chart should correspond to the components of the oral exam

• The back side of the chart should include a place to record the oral problems, the treatment plan, and recommended follow up treatments.

Fig 8. Example dental chart front side (left) back side (right)

Photo documentation

• Standard cameras can be used to document oral findings. Cannon Elph1 is a good choice. • Oral endoscopy can be performed with a ridged endoscope at a 70-90 degree angle2. (Fig. 9) • Specific equine oral cameras have been designed3.

Fig. 9. Using a rigid endoscope for oral examination of a horse (left photo); close-up image of a mandibular cheek

tooth (right photo)

Instrumentation for Odontoplasty • Hand Floats or rasps. Two types of hand grips either straight or pistol grip. The working head can

have several different angles that are used on specific teeth in the dental quadrants. The cutting surface is generally machined carbide blades or carbide chip. The blades have different levels of cutting ability depending on the operator’s choice and generally are labeled as fine, medium and coarse. Most can be re-sharpened. These are still a good choice for practitioners performing a limited to moderate number of procedures or practitioners with limited experience.

• Power Reciprocating - The function of these instruments is the same as hand floats with an electric motor providing the force to move the shaft of the float. There are different shaft/head configurations similar to hand floats that are utilized on specific teeth in the dental quadrant. The blades are often identical to hand floats. There is a battery operated variation of the reciprocating instruments made specifically for the hard to access buccal surface of the 109,110,111 teeth4. It has a 1 inch carbide blade in an upward angle with a shortened stroke. This is a safe, economical option for practitioners performing a moderate amount of dentistry.

• Rotating bur with carbide or diamond abrasive- These instruments are generally driven by a flex drive cable and motor. The headpieces are of different lengths and guard configurations to protect the soft tissues. The bur has a cutting surface the is rotating parallel to the tooth surface and increases the ability of the instrument to walk off of the tooth and damage soft tissue especially when double cut carbide burs are utilized. Diamond grit coated burs are the safest, friendly to soft tissues, and are the least aggressive to the tooth. There is a risk to thermal injury of the tooth if excessive tooth material is removed and the operator fails to periodically rinse the tooth surface with water. This type of instrumentation has resurfaced with the advent of battery electric motors connected to the flex shaft and worn on a belt or harness by the operator. They provide adequate power with a very lightweight instrument in the oral cavity some also equipped with the option of water cooling56.

• Right angle drive with flat disk and apple core with carbide chip or diamond abrasive. These instruments have a right angle gearbox on the end of a shaft that turns a 1 inch carbide chip or diamond disk. This type of instrument is soft tissue friendly and easier to control on the tooth surface. They are often driven with a drill motor style electric motor or flex shaft connected to an electric motor7. One unit has a changeable angle of the cutting surface, water cooling, suction and a battery driven motor8. The instrument without suction or water cooling can produce a substantial amount of tooth dust that the operator should avoid inhaling. These instruments are the easiest to use, are purpose built for equine dentistry but also carry the largest price tag.

Special considerations: Management of sharp enamel points Commonly performed procedures in horses involve identification and management of dental elongations and sharp enamel points. Modern, motorized instrumentation allows for accuracy and safety if used properly.

Figure 2 Sharp enamel points maintain close contact with the mucosal lining of the cheek (green arrows) and tongue (blue arrows).

• Odontoplasty is a term that can be used to describe contouring of the tooth surface (e.g., dental floating)

• Occlusal adjustment encompasses odontoplasty of sharp enamel points as well as reduction of tooth elongations that involve dentin, cementum, and occlusal enamel (dental elongations resulting from abnormal physiological dental attrition).

• Crown reduction procedures are performed in order to alleviate: Mastication problems Shifting of teeth to an abnormal position due to traumatic occlusion Premature attrition of the crown.

• Sharp dental points can be alleviated using hand held files (‘floats’) and / or motorized instruments • Hand instruments - the floating procedure is performed ‘by feel’ with the horse’s head at the level of

the operator’s waist or chest. This requires minimal sedation and works well for most horses with relatively normal occlusion that needs only odontoplasty of sharp points of the cheek teeth. The horse’s head can be periodically elevated and the oral cavity visually evaluated during the procedure.

• Motorized instruments- the veterinarian performs the floating procedure with the animal’s head elevated at a height that allows visualization of the mouth while maintaining a comfortable working position. Visual dentistry has some advantages over dentistry by feel, especially in horses with dental pathology or severe wear abnormalities.

• With manual or motorized tools, the most difficult areas to access are the buccal aspect of the upper caudal molars and the lingual aspect of the lower caudal molars

• It is important to palpate the teeth after floating to ensure the procedure has been successful in removing sharp points

Fig. 3. Positioning the floats correctly will remove sharp points and create a smooth, contoured buccal/lingual edge. It is important to preserve the normal slope of the chewing surface.

Management of deciduous premolar teeth

• Worn crowns of the deciduous premolar teeth (caps) become loose and subsequently either displaced or shed into the mouth; Retained, split, or displaced deciduous premolars can cause irritation and inflammation

Permanent cheek tooth (Triadan designation)

Age of eruption

06 2.5 yr.

07 3 yr.

08 4 yr.

09 10-12 months

10 2 yr.

11 3.5 yr.

Approximate eruption ages for the permanent cheek teeth

• Generally, the deciduous cap can be extracted safely if the permanent tooth has erupted and a line of demarcation is visible between the cap and erupting tooth

• In order to remove a premolar cap, use forceps to grasp and roll the cap toward the palate/tongue • When caps are removed, the underlying permanent tooth will continue eruption and should be in wear

in 3–4 months Management of wolf teeth (PM1)

Fig. 6. Basic instrumentation for extracting wolf teeth (left); infiltration of local anesthetic using a butterfly catheter (center); using an elevator to loosen the attachments of a wolf tooth (Triadan 105).

• Wolf teeth usually erupt during the first year of life • The majority of wolf teeth do not cause problems • Displaced or sharp-crowned wolf teeth can cause buccal pain and ulceration when pressure is placed

on the cheeks • It is customary to extract wolf teeth in young performance horses • Wolf teeth should never be extracted without the use of sufficient analgesia; this includes intravenous

sedation/analgesia and local anesthetic • Wolf teeth are loosened with a small luxator to disrupt the periodontal ligament attachments, and

extruded from the socket with a forceps after loosening • In some instances, sudden excessive hemorrhage occurs during wolf tooth extraction as a result of

damage to the major palatine artery o If this occurs, the extraction procedure is immediately discontinued and the horse’s head

should be elevated to about the level of the withers. In the majority of cases, hemorrhage can be controlled using direct pressure for several minutes with a gauze compress

Management of canine teeth • Teeth 104, 204, 304, and 404 are usually present in most male horses over 5 years of age • Canine teeth normally cause few if any problems • It is common to detect calculus accumulation around the canine teeth which is easily removed with a

small forceps, hand scalers, or mechanical scalers. • The practice of shortening the clinical crown of the canine teeth is discouraged; however conservative

blunting of the most coronal aspect of the clinical crown can be performed safely on a tall, sharp canine tooth with a file or motorized instrument

• Erupting canine teeth in 4–6-year-old horses can cause subgingival pain and irritation that has been manifested by head shaking or other bad habits

Assessment of chewing function A simple method of assessing cheek teeth occlusion involves raising and supporting the horse’s head, then sliding the mandible to the left and right while retracting the cheek for viewing. As the examiner slides the mandible laterally the cheek teeth on the ipsilateral side normally slide into occlusion. Using this technique the veterinarian can feel and/ or visualize areas that may interfere with mastication (i.e., an overlong tooth or protuberance). Rucker determined a method to evaluate cheek teeth occlusion by measuring the distance that the mandible can be moved to the left or right until the cheek teeth come into occlusion (‘Excursion to Molar-Contact Distance, or EMC distance’). Measurement of EMC distance has been used in calculations involving masticatory function

• When the horse’s poll is flexed the mandible protrudes rostrally, and when the poll is extended the mandible retracts caudally. Rostral-caudal mobility of the mandible (RCM) is determined by measuring the distance the labial edge of the mandibular incisor moves in relation to the opposite maxillary incisor during the range of motion. Normal RCM distance is about 4-5mm, and increases slightly immediately following dental floatation.

SUMMARY

By current standards, proper instrumentation for carrying out dental examination in horses includes a dental speculum, bright source of light, and dental mirror. Equine dentistry should include a thorough examination, documentation, and the necessary instrumentation for odontoplasty or occlusal adjustment. Product Notes 1 Cannon PowerShot ELPH 350HS www.shop.usa.cannon.com 2 Storz 70Degree 35cm rigid endoscope and camera www.pferdefit-dental.de 3 Equine EZ view camera www.veterinarydental products.com 4 De-MaX III Reciprocating Float www.equinedentalinstruments.com 5 Power Handles MAI Animal Health www.maianimalhealth.com 6 Horse Dental Equipment,www.horse-dental-equipment.us 7 Power Floathttp://www.powerfloat.net 8 Flexi-Float Equine Dental systemwww.veterinarydentalproducts.com Bibliography

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• O'Leary, J. M., et al. (2013). "Pulpar temperature changes during mechanical reduction of equine cheek teeth: comparison of different motorised dental instruments, duration of treatments and use of water cooling." Equine Vet J 45(3): 355-360.