Crowns in Veterinary Patients

In human dentistry, a “crown” (a metal or metal-covered-by-ceramic covering, cemented to the crown of a damaged or abnormal tooth) is commonly used to improve the appearance of abnormal teeth and to restore function and strength to a tooth that has been damaged.

A crown is rarely medically necessary in veterinary patients, except when function is essential, as in working dogs (e.g. military, police or security dogs), although a crown may reduce the risk of failure of a restoration and recurrence of endodontic disease. Placing a crown requires an additional anesthetic episode for cementation of the crown following completion of endodontic (root canal) treatment and preparation of the tooth; this involves additional expense.


Fig 1. Metallic crown placed to help protect the tooth treated by root canal therapy. 
 

Fig 2. Tooth-colored ceramic crown on a mandibular canine tooth.

The most common crown materials for veterinary patients are cast metal alloys. They provide superior strength and require the least removal of tooth material when preparing the tooth for the crown, compared with a ceramic-covered (tooth-colored) crowns.

Information for Owners

Good oral health is an important part of good general health for your pet.

Signs of oral and dental diseases in dogs and cats:
- Bad breath.
- Loose teeth or teeth that are discolored or covered in tartar.
- Your pet shies away from you when you touch the mouth area.
- Drooling or dropping food from the mouth.
- Bleeding from the mouth.
- Loss of appetite or loss of weight (this combination can result from diseases of many organs, and early veterinary examination is important).
If you think your pet needs dental care, the College recommends that you make an appointment with your veterinarian, who will recommend a referral to an AVDC diplomate if indicated, or you may contact an AVDC Veterinary Dentist directly. Please note that the AVDC does not respond to enquiries about individual patients.

Plaque and Tartar Control

Prevention of the most common oral disease in pets (and in people!) consists of frequent removal of the dental plaque and tartar that forms on teeth that are not kept clean. The Veterinary Oral Health Council (VOHC®) awards its Seal of Acceptance to products that successfully meet pre-set criteria for effectiveness in controlling plaque and tartar deposition in dogs and cats. The VOHC is an entity of the American Veterinary Dental College. If you would like information on products that will help control deposition of dental plaque and tartar on the teeth of your pet, click Veterinary Oral Health Council.

National Pet Dental Health Campaign!

AVDC is proud to partner with the American Veterinary Dental Society, the Academy of Veterinary Dentistry, the American Veterinary Medical Association, Hill's Pet Nutrition, Inc. and the Veterinary Oral Health Council, in sponsoring activities that will help to increase understanding of the importance of oral health for our pets. For information, click National Pet Dental Health Campaign

Bite relationships in cats

This bite is right!
There are characteristics of normal occlusion in cats.  It is most important for the occlusion to be functional and comfortable.



Front view of a comfortable bite.  Dr.
Kressin was holding this cat and the
right upper canine became hidden by
the lower lip.  Note the position of the
upper and lower incisors and the
relationship between the canine teeth.



Right side view. Note the interdigitation
of the premolar teeth.



Left side view.

Dr. Kressin recommends that owners and their veterinarians routinely examine their cat's mouths during the developmental period and throughout life.  Make it a habit to brush your cat's teeth as you do your own!  Notice the relationship of the upper and lower jaws and how the teeth align.  This is called the bite evaluation or the occlusal evaluation.  Malocclusion is an abnormal occlusion (abnormal bite).

Does your cat have the normal number of teeth?  You can view a dental chart we use for cats and read additional information about bite evaluation.  Sometimes extra teeth or supernumerary teeth can result in abnormal bite relationships.  Supernumerary teeth may contribute to tooth crowding and to the development of periodontal disease.  Occasionally, teeth grinding may result from supernumerary teeth.

Is the bite right and does it matter?

The bite is absolutely important.  Our goal is to make the bite right and confortable for pets!

The occurance of malocclusions in cats is less common than in dogs; however, they do occur.  The resulting malocclusion may be minor and functional or major malocclusions can result in traumatic bites to the cat's oral tissues.  The trauma from teeth hitting teeth or teeth hitting soft tissue can be uncomfortable or even result in other problems.  When the bite is not right, teeth crowding or gingival trauma may contribute to the development of periodontal disease.

This bite is not right!



Harry Potter; wry bite.  Both lower mandibles (jaws)
are shorter than normal.  The left lower mandible
is shorter than right mandible.  The lower right
secondary (adult) canine strikes the palate (roof
of the mouth).  The left lower canine has not
erupted completely.  This traumatic occlusion can
result in a hole in the palate.

Harry Potter's owners and veterinarian noticed the problem developing.  Surgical extraction of the primary (baby) canines helps avoid the interlock between upper and lower teeth.  This allows (but does not guarantee) for normal jaw growth.  The interlock prevents normal jaw growth and development.

This bight is not right.


Both mandibles are longer than normal
resulting in a traumatic malocclusion.



The left upper canine interferes with the
left lower canine.  The lower canine is
malpositioned as a result of the trauma.

         

A traumatic malocclusion.                          Alternate view.



Alternate view of the lower canine
teeth striking the upper lip.  There is
a disparity in jaw length.  The upper
jaws are relatively shorter than the lower
jaws.  The lower canines traumatize
the upper lip!

         

Disparity of jaw length.                            The mandibles appear longer than the maxillas.

         

Oral mass developed secondary to                       Alternate view.
the traumatic occlusion.

Open mouth jaw locking is an emergency.  Dr. Kressin has seen this occur from super-eruption of the upper canine teeth in cats.  It is usually associated with chronic periodontal disease and alveolar osteitis.  The upper canine tooth and the lower canine tooth came into occlusal contact and the cat was unable to close the mouth.

Open mouth jaw locking may also be due to TMJ dysplasia, TMJ luxation or the entrapment of the mandibular coronoid process with the zygomatic arch.  Dental radiography or computed tomography can be very helpful in evaluation of the TMJ.  This is not a common condition in cats but has been reported in the oriental breeds.

A dental consultation is recommended if there are persistent primary teeth, dental interlock or a traumatic malocclusion

Brush my Dog's WHAT?

Proper position of toothbrush against tooth

What would happen if you stopped brushing your own teeth? Even if you only ate hard food as most dogs do, there still would be problems. You should be brushing your dog's teeth at least twice weekly, daily if you can manage it. It's not as difficult as you might imagine.
What are the benefits? Brushing removes the daily accumulation of plaque from the teeth. Even though dogs do not commonly get cavities, they do suffer from periodontal disease. If untreated the gum disease can lead to pain and loss of teeth.

Dental technician brushing dog's teeth

How to brush teeth? Step one is to pick an appropriate pet toothbrush. Save yourself time by not buying a child's toothbrush which is usually too hard for dogs. The ideal dog toothbrush will have a long handle, an angled head to better fit the mouth and extra soft bristles. Another option is the finger toothbrush that fits over the tip of your finger.
Step two is to select an appropriate toothpaste. The best pet toothpastes contain enzymes that help control plaque. Try to avoid toothpastes with baking soda, detergents, or salt sometimes found in human pastes. Fluoride may be incorporated to help control bacteria. Rather than placing the paste on top of the brush try to place it between the bristles. This allows the paste to spend the most time next to the teeth.
Step three is to get the brush with paste into your dog's mouth and all the teeth brushed. Most pets accept brushing if they are approached in a gentle manner. If you can start when they are young, it's quite easy, but even older pets will accept the process. Start slowly, you can use a washcloth or piece of gauze to wipe the teeth, front and back in the same manner you will eventually be using the toothbrush. Do this twice daily for about two weeks and your dog or cat should be familiar with the approach. Then take the pet toothbrush, soak it in warm water and start brushing daily for several days. When your pet accepts this brushing, add the toothpaste.
The toothbrush bristles should be placed at the gum margin where the teeth and gums meet at a 45 degree angle. The movement should be in an oval pattern. Be sure to gently force the bristle ends into the area around the base of the tooth as well as into the space between the teeth. Ten short back-and-forth motions should be completed, then the brush should be moved to a new location. Cover three to four teeth at a time. Most attention should concentrated on the outside of the upper teeth.
In summary, small animal home care should include daily (or at least every other day) brushing, using an enzymatic pet toothpaste. Taking an active role in the care of your dog's dental care will help reduce dental disease, bad breath and potential life threatening heart and kidney disease. Everyone wins.

Dental Anatomy

Incisors -- Dog There are four types of teeth in small animals: incisor, canine, premolar, and molar. Nature designed each to serve a special function. Incisors are named first, second and third; or central, intermediate, and lateral, based on their location in the mouth. There should be six incisors in the maxilla (upper jaw) and six in the mandible (lower jaw). Incisor teeth are used for shearing and grooming. Normally, the lower canine should intersect the upper lateral incisor and upper canine There are two large canine teeth located in the mandible and two in the maxilla. The canines are designed to grasp and tear with great pressure. Premolar teeth have sharp edges used for shearing. In the dog, there are four premolar teeth on either side of the upper and lower jaws. Dogs have four molars in the upper jaw and six in the lower. Molars have a flat surface used for grinding. Normal interdigitation of premolars Lower first and second molars effected with periodontal disease Lower canine, third and fourth premolars, and molar in a cat The cat has three premolars on each side of the upper jaw identified as second, third, and fourth; and two lower premolars on each side of the lower jaw, called third and fourth. Cats have one upper and lower molar on each side. The primary or deciduous incisors erupt at one to three weeks of age while the primary canines erupt at three to four weeks. The remaining temporary premolars and molars should emerge by ten weeks. The first premolar and all the molars erupt only as adult teeth. The remaining premolars, canines, and incisors appear in the oral cavity first as primary (temporary, deciduous, or baby) teeth. Secondary (adult) teeth usually appear at four months. Adult incisors appear first followed by canines, premolars, and molars. The complete adult dentition should be present in most breeds by eight months of age. Upper third and fourth feline premolars A tooth is composed of a portion above the gum line called crown and a section below the gum line called the root. Enamel, the hardest mineralized tissue found in the body, covers the crown. Cementum, which is attached to the periodontal ligament, covers the root. Dentin, softer than enamel, makes up the bulk of the tooth. Inside, the pulp is composed of live tissue, that contains nerves, blood vessels and lymphatics.

 

Twelve Steps of the Professional Teeth-Cleaning Visit

Qualified veterinary dental technician ultrasonically cleaning dog's teeth

No other procedure performed on small animals does more to help patients than periodic teeth cleaning and after care. The dental visit for cleaning must be performed in a methodical manner. All twelve steps are important and interlinked. When one step is not performed, long term patient benefit suffers.
1) Oral examination on the unanesthetized animal. Begin with the face. Check for swellings and painful areas. Look at the eyes, are they the same size? Is there swelling under one eye? Open and close the mouth to check for pain or crepitus in the temporomandibular joints. Examine the teeth and gingiva for pathology. Examine each tooth rather than the mouth globally. If there is even a small amount of tartar touching the gingiva this is disease and needs immediate removal.

Severe Bone Loss, Rear Root Mandibular 1st Molar Tooth Due to Periodontal Disease

2) Oral examination under general anesthesia. We examine individual teeth for mobility, fractures, malocclusion, and periodontal disease (probe for pocket depths after calculus is removed).
3) Supragingival (above the gumline) plaque and tartar removal using calculus removing forceps, hand instruments, and power scaling equipment.
Supragingival deposits are removed from buccal, lingual, and interproximal surfaces of the teeth.

Ultrasonic Cleaning

When used properly, the ultrasonic scaler removes plaque and tartar from the teeth. Heat generated by an ultrasonic scaler can cause severe damage to the tooth and periodontal support. Ultrasonic units must be used on crowns and exposed root surfaces only.
The ability to remove tartar and potential damage by an ultrasonic scaler depends on power settings, time of exposure, amount of pressure applied, and sharpness of the tip.
Regardless of the type of power scaler, use a feather light touch, keeping the water-cooled tip moving in constant sweeping motion to avoid thermal injury. Use the side of the tip not the point to remove tartar.
4) Subgingival (below the gumline) scaling, root planing, curettage. Curettes are used to remove subgingival deposits. If indicated, the three parts of this step include:

Cleaning calculus from below the gumline

Root scaling: removal of plaque and calculus from the root surface. The goal is to disorganize and lavage bacteria living subgingivally. This creates a healthier environment for healing and reattachment. Curettes, or slim ultrasonic tips are used.
Root planing: the smoothing of roughened root surfaces by debriding diseased cementum and removing embedded calculus produces a clean smooth surface free of endotoxin. Root planing is performed with a curette used in overlapping strokes. Crosshatch planing creates a smooth surface while maintaining root anatomy.
Removal of all exposed cementum may not be helpful to periodontal health. Cementum contains chemicals that enhance re-attachment of periodontal ligament. Bacteria do not penetrate into the cementum. Stripping cementum by root planning removes potential reattachment resources.
Subgingival Curettage is removal of the gingival pocket’s diseased soft tissue inner surface. The rationale for the procedure is to convert chronically inflamed ulcerated lesions in the soft tissue wall of a periodontal pocket, into a clean surgical wound. This promotes healing and readaptation of tissue to the tooth surface.
Subgingival curettage is done without direct visualization of the root surface. It is performed with a curette held in the reverse position, placing the blade against the soft tissue for epithelial removal. The curette tip is used to remove remains of the epithelial junction. This allows for optimal reattachment and reduction of the periodontal pocket.

Polishing Teeth

5) Polishing. Regardless of how careful we are during the scaling/curettage phase of teeth cleaning, minor defects of the tooth surface occur. Polishing smoothes out the defects and removes plaque missed during previous steps. Pumice or polishing paste is used on a polishing cup for the procedure.
When polishing, use firm pressure until the cup edge flares. Overheating is prevented by relieving pressure slightly as the cup moves over each tooth.
6) Irrigation. With irrigation, diseased tissue and plaque are removed from the pocket or sulcus. Water spray and/or a 0.1-0.2% Chlorhexidine gluconate solution are commonly used. Blunted 23G needles are available for manual irrigation. Power irrigation is supplied on many delivery systems.

Fluoride used to decrease discomfort and harden enamel

7) Fluoride is placed on dry teeth and allowed to remain undisturbed for at least four minutes.
  

Intraoral x-rays taken to evaluate degree of periodontal disease

8) Post cleaning examination and diagnostics. After cleaning, teeth are examined individually via periodontal probing, compressed air application to the gingiva to examine for retained calculus, Shepherd’s hook exploration, disclosing solution, and radiology (if indicated).
9) Charting. Record disease present before therapy. Charting must include missing , loose, fractured , and discolored teeth, as well as feline oral resorptive lesions, periodontal pocket depths, gingival recession, and other significant lesions.

Certified veterinary technician examining each tooth after cleaning

10) Therapy to treat lesions noted above.
After treatment records must include:

	Dental care performed
	Follow up recommendations
	Antibiotics dispensed
	When the next radiographs are recommended
	When the next dental exam recommended
	Home care instructions

11) Home care instructions. The pet owner is an integral part of our dental team. The dental visit is not complete until discussion is held on maintaining and improving oral health. Home care is the single most important procedure the owner can do to maintain oral health. If performed regularly, daily brushing will dramatically increase the interval between teeth cleaning appointments.
Plaque is constantly being made and deposited in the mouth. Humans have a buildup of plaque in the morning, that makes our breath smell bad. Proper home care can keep plaque buildup under control. People brush their teeth several times daily to remove plaque -- why not our pets?
The goal of dental home care is to remove plaque from tooth surfaces and gingival sulci before it mineralizes into calculus, a process that occurs within days of a teeth cleaning. Success depends on the owner's ability to daily brush the teeth, as well as the dog or cat’s acceptance of the process. True oral cleanliness can only be achieved through the mechanical action of toothbrush bristles above and below the gingiva.
Home care is best started at a young age before the adult teeth erupt. The perfect time to introduce dental home care is at the first puppy or kitten visit. The client-animal bond as well as the client-veterinary bond is enhanced when daily brushing is performed following instructions given at the animal hospital.
Our staff members are knowledgeable about tooth brushing techniques. Each teeth cleaning visit concludes with review of tooth brushing techniques. Nothing beats "hands on" instruction.
Clients often ask, "doesn’t hard food keep teeth clean?" Some believe when their dog or cat chews on hard food or biscuits, mineral deposits are broken down and the teeth stay clean. This is not true. True, animals on soft diets accumulate plaque more readily than those on dry foods, but the only way to keep teeth clean above and below the gum line is by daily brushing.
Brushing instructions must be more than telling you it would be a good idea for you to brush your pet’s teeth, then selling a toothbrush. We will show you how to properly use the tooth brush and paste, and observe you perform the procedure.
How to get the pet to accept tooth brushing. Proper technique involves applying the bristles at a 45 degree angle to the gingiva. Use small circular motions around the outside of the teeth, being sure to get the bristles under the gumline. It is not as important to brush the inside of the teeth, as dogs and cats do not have the buildup of tartar on the palatal or lingual sides of their teeth as people do.
The most important area to keep clean is the sulcus under the free gingival margin. It is plaque and tartar underneath the gumline, that is removed by daily home care. Adding products such as Oxyfresh to the drinking water or rubbing the teeth with dentifrice impregnated pads may help in home care, but understand that periodontal disease begins in the gingival sulcus. Home care is most effective when the dentifrice is brushed below the gumline.
Start with a healthy comfortable mouth. Untreated problems can cause pain, and a non-compliant patient. Dental pathology must be cared for first.

Finger Toothbrushes

Choose a proper toothbrush and toothpaste. Toothbrushes have bristles that reach under the gumline and clean the space that surrounds each tooth. Plaque accumulates in this space. Devices such as gauze pads, sponge swabs, or cotton swabs remove plaque above the gumline, but cannot adequately clean this space below the gumline.
The size of toothbrush chosen is important. There are specially made brushes to fit into the large mouths of long muzzled dogs as well as small brushes for cats.
Each dog or cat must have his or her own brush. Sharing brushes may result in cross contamination of bacteria from one pet to another.
Introduce the toothpaste and tooth brush. When you sense the pet is anxious to the brushing procedure, give reassurance by talking and try again. Expect progress not perfection. Reward progress immediately with a treat, or a play period after each cleaning session
Take time. Each pet is different. Some will be trained in one week while others will take a month or more. The payoff is well worth the learning curve.
The degree and type of home care products dispensed depends on:

	Type of dental periodontal pathology
	Stage one and two-daily brushing with dentifrice
	Stage three where periodontal disease has been established: Daily brushing with fluoride containing toothpaste, or Dentivet toothpaste plus twice weekly application of stannous fluoride gel Pulse therapy antibiotics
	Stage four-advanced periodontal disease homecare includes: zinc ascorbate spray 3-4 times daily HexaRisne (Vibrac) twice daily Or CHX-Guard (VRx Products)-combination of Chlorhexidine gluconate and zinc Pulse therapy antibiotics

At the end of two weeks, Stannous fluoride gel twice weekly can be substituted for the chlorhexidine spray.
12) Follow-up progress visits are as essential as any of the preceding steps. The time between oral exams is based on the degree of disease and the client’s ability to provide home care. Some severe periodontal cases are rechecked monthly, while pets that have been treated for grade one gingivitis, and their teeth brushed once or twice daily, can be rechecked every six months. The reminder interval for recheck can be linked to degree of periodontal disease in the computer.