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DENTAL FAQs
What Can I Do For a Broken Tooth?
If a patient presents soon after a tooth fracture occurs, there are a number of treatment options available.
Vital pulpotomy - technically this procedure is a partial pulpectomy and direct pulp capping. In most cases, if seen within 48 hrs of the fracture occurring, the pulp will be still be alive and the tooth can potentially be saved. Radiographs are taken to check for root fractures. A vital pulpotomy involves removal of some of the inflamed pulp, then dressing the remaining pulp with calcium hydroxide. This stimulates the formation of a dentinal bridge at the site, sealing the pulp chamber. The site is then filled and restored to permanently seal and protect the pulp cavity. This allows immature teeth to continue to develop and the root apex to close. The tooth is not restored to it’s original height as the restoration will not withstand the forces in the mouth (unless a full crown is manufactured) The tooth should be radiographed every 6-9 months for 2 years to monitor dentinal bridge formation and pulp cavity development. Vital pulpotomy is most successful (about 80%) in immature teeth of young animals (<18months-2 years) within 2 weeks of the fracture occurring. In older animals (>18 months), treatment should be performed within 48 hours of the fracture occurring. After this time, pulp inflammation is usually too severe for the procedure to succeed. If the procedure fails (eg restoration is lost), root canal treatment or extraction is required.
Fractures older than 2 weeks in immature animals or older than 48 hours in older animals require either root canal treatment or extraction.
Root Canal Therapy – in cases of chronic tooth fracture, the pulp is usually irreversibly inflamed or necrotic. The aim of root canal therapy is to completely remove the pulp and any infected tissue from the pulp chamber, to disinfect the pulp chamber then fill it with an inert, antibacterial material, seal the apex then close the fracture or access site. Although the tooth is no longer alive, it is free of infection and should remain stable and functional. While root canal therapy can be performed on any tooth, it is generally most successful in anterior teeth such as incisors or canines in dogs and canine teeth in cats. The upper carnassial tooth (upper 4th premolar) is a tooth that is frequently fractured due to the large forces applied to it. As this is a 3 root tooth, successful cleaning, sterilisation and filling can be difficult. If the chewing behaviour that caused the fracture (ie bones, rocks) persists, the treatment often fails, necessitating extraction.
Immature teeth (ie root length and apex not fully developed) with necrotic pulps usually require an intermediate treatment prior to root canal therapy. After the necrotic pulp tissue is removed, sterile calcium hydroxide is placed into the pulp chamber to stimulate closure of the root apex, which can take 6-24 months. Ideally the tooth should be re-radiographed every 3 months to check for closure of the apex or complications eg infection. The calcium hydroxide dressing may need to be changed every 4-8 months (as fresh dressing provide more stimulus) until the apex is closed. Once apical closure is achieved, the temporary dressing is removed and standard root canal therapy can be performed.
Extraction - if owners do not wish to save a fractured tooth then extraction is recommended. If left intact, the pulp will eventually die and become infected, resulting in chronic inflammation, infection and pain.
What Can I Do For Occlusion Problems?
Base narrow/lingually displaced mandibular canines
This is one of the more commonly seen malocclusions. Causes can include retained deciduous teeth, narrow mandible and abnormal position of the tooth buds. Regardless of cause, the end result is usually trauma to the gingiva and palatal tissues by the deciduous and/or permanent canine teeth. Similarly, animals with a short mandible (brachygnathic) may also develop palatal trauma due to the impact of the mandibular canines. This is a painful condition and if left untreated can result in difficulties eating, mouth-shyness and penetration into the nasal cavity. There are several treatment options for this condition – the most appropriate treatment will depend on the severity, age of the animal and owner compliance
Extraction – Retained deciduous teeth should be always be extracted (there should never be an adult and deciduous tooth present in the socket at the same time). Removal of the permanent canines is the least favourable option as it greatly reduces the strength of the anterior mandible. A better option is -
Crown reduction – removal of the crown of the mandibular canines at the level of the adjacent teeth eliminates the source of trauma yet maintains the jaw strength provided by the tooth roots. The exposed pulp is treated (similar to a vital pulpotomy) and the tooth sealed, retaining its vitality and function. This treatment is successful in about 80% of cases
Ball therapy – if there is adequate space between the maxillary 3rd incisors and canines then ball therapy may be suitable. This treatment uses a firm rubber ball, of the appropriate size, to act as a removable orthodontic appliance. The ball applies lateral force to the mandibular canines when held in the mouth, gently forcing them into a more normal occlusion. Once in this position, the natural interlock of the teeth acts as a retainer. This treatment is most appropriate for young dogs with no major jaw length discrepancies.
Orthodontic appliances – in more severe cases, placement of an acrylic plate/incline plane may be a more suitable treatment option. A fixed acrylic plate is place across the palate (behind the upper incisors) and grooves are created to apply lateral pressure to the canine teeth when the mouth closes. Plates stay in the mouth for several weeks minimum, depending on the rate of jaw growth and teeth movement. Plates may require adjustments (under GA) during the treatment period.
Prognathic mandible
Often referred to as an ‘undershot’ jaw, this problem is usually due to a long mandible (though can be the result of a short maxilla). Although unattractive, this type of malocclusion may not cause oral trauma or pain and is normal for some breeds (eg Boxer, British Bulldog). If teeth are making abnormal contact and causing pain and trauma, treatment is warranted. This may involve removal of the offending teeth or odontoplasty – shaving off a little of the crown to decrease or eliminate contact.
Lance canines
Otherwise known as rostrally deviated maxillary canines, this condition is sometimes seen in Shelties. In cases where the condition is atraumatic, treatment may not be required. There is, however, an increased risk of periodontal disease due to the reduced interdental space. Brushing and homecare is strongly recommended. In cases involving oral trauma, the teeth can be treated orthodontically (brackets and elastic chain) to move them into a more normal position.
Even bite
The incisor teeth should occlude with a scissor bite, that is, the upper incisors sitting in front of the lowers when the mouth is close. Jaw length discrepancies and retained deciduous teeth can disrupt the normal bite, causing some or all of the incisors to occlude crown to crown. This may result in abnormal crown attrition, incomplete tooth eruption and pain. Treatment may include selective extractions and odontoplasty to minimise crown contact. Appropriate cases may be treated orthodontically
Orthodontic procedures should not be performed for cosmetic purposes, or for dogs used for breeding purposes. Orthodontics should only be used to treat and eliminate occlusion problems causing oral pain and trauma.
What Can I Do for a Facial Abscess?
A swelling/abscess to the cheek or side of the face between the nose and eye is often the result of dental disease. The problem frequently involves the maxillary 4th premolar, though can be associated with the maxillary 3rd premolar or first molar. Crown fracture and subsequent tooth root abscess is a common cause. Blunt trauma without crown fracture can also result in tooth death and subsequent infection. Non-dental causes such as neoplasia, foreign bodies, ocular disease etc should be ruled out.
Whilst tooth root abscesses often respond rapidly to antibiotics and anti-inflammatories, the underlying cause must be eliminated to prevent recurrence. This may involve root canal therapy (see previous) or extraction of the offending tooth. As this condition causes low grade chronic pain, medical therapy is recommended until definitive treatment can be performed.
What Can I Do For a Discoloured Tooth?
Tooth discolouration is usually the result of trauma. This can be blunt trauma, such as a blow with a stick or ball, or chronic trauma from chewing eg bones, rocks. Acute trauma generally causes haemorrhage and discolouration within the tooth – from pink initially through to bluish then black/brown (like a bruise). Chronically discoloured teeth are often dead and have the potential to become infected. Tooth vitality is determined by transillumination and intra-oral x-rays. If dead, a tooth should be treated endodontically (if appropriate) or extracted to prevent chronic pain and infection.
What Can I Do For Feline Odontoclastic Resorptive Lesions?
Also known as neck lesions, cervical line lesions etc, these are painful, insidious lesions that erode through the enamel, dentin then into the pulp. Chronic lesions may obliterate the entire crown and affected teeth often have resorbed tooth roots. In the past, treatment has been performed to try and restore affected teeth. Unfortunately this fails as the odontoclastic cells remain active and destruction continues under the restoration. The treatment of choice is tooth extraction. Intra-oral x-rays are recommended to assess root ankylosis and resorption.
What Can I Do For an Oronasal Fistula?
As there is only a thin layer of bone between the maxillary canine socket and the nasal cavity, severe periodontal disease or extraction and bone loss can readily lead to the development of a fistula. When left untreated, oronasal fistulas (ONF) can lead to persistent nasal discharge and infection. Small, acute ONFs can often be treated by creating a mucogingival flap which is closed over the defect and sutured in place. Larger, more chronic ONFs require more extensive treatment as they are often chronically infected and lined with epithelial tissue. Double flap closures using tissue from the palate and lip is usually successful, though repeat treatment may be required in some cases. Fistulas can also be associated with the maxillary 3rd and 4th premolars and molar 1 (oroantral fistula).
What Can I Do for a Displaced Tooth?
Complete (avulsion) or partial (luxation) displacement of a tooth from its socket may occur secondary to trauma. If treated quickly, the affected tooth can often be saved. An avulsed tooth needs to be kept moist (to keep the periodontal ligament alive), ideally in saliva, milk or cold water. The tooth should be cleaned as little as possible to avoid destroying the periodontal ligament cells. Once re-implanted, the tooth needs to be splinted to allow it to stabilise. As the blood supply to the pulp is severed, root canal therapy is recommended about 2 weeks after re-implantation. Splinting may be required for 4-6 weeks.
Although still within the alveolus, luxated teeth usually also have a damaged blood supply and require similar treatment of splinting and root canal therapy.
In cases of severe periodontal disease predisposing to avulsion/luxation, affected teeth should be extracted and the alveolus closed.
Dental Problems in Pocket Pets
Rabbits – incisor malocclusion is a relatively common problem in pet rabbits. Rabbits should have a scissor bite, ie the lower incisors occlude behind the uppers, allowing normal wear of both sets of teeth. If the incisors occlude end to end (even bite) or with the lowers in front of the uppers, normal wear does not occur and the teeth continue to grow. This can lead to root elongation and overgrowth. In the case of the upper incisors, this can result in occlusion of the nasolacrimal duct (runs close to the root) and persistent ‘weepy’ eyes. Overgrowth of the incisors can also result in trauma to the oral soft tissues, jaw abscesses and eventual cheek teeth overgrowth. Incisor malocclusion can be genetic, secondary to trauma (eg broken teeth) and poor diet.
Treatment of incisor and cheek teeth malocclusion often becomes a lifelong prospect. Due to the rapid rate of growth of the teeth, regular tooth shaving is required to maintain a functional occlusion. Incisors can occasionally be shaved under manual restraint using a high speed dental drill. Clipping with nail clippers is not recommended as it can damage the tooth roots, exacerbating the problem. In many cases, a short, light anaesthetic is required to shave the incisors safely. This may need to be performed fortnightly up to monthly or less frequently, depending on the animal. Shaving of the cheek teeth is performed under a short, light GA to allow adequate opening of the mouth. Shaving is usually performed with a slow speed dental handpiece.
Extraction of all the incisor teeth can be performed in rabbits with ongoing incisor problems. Rabbits can cope very well without these teeth, though some dietary modifications are required.
Rats and Mice – also have continuously growing incisor teeth. Incisor malocclusion is often secondary to trauma and incisor fracture. Without an opposing tooth to wear against, the unaffected incisor/s will overgrow, causing soft tissue trauma and difficulty eating. Under a light anaesthetic, the incisors are shaved back to a more normal level, allowing them to occlude and wear. This may need to be repeated several times before the occlusion returns to normal. In less severe cases, increased chewing activity may be sufficient to wear the teeth down. As with rabbits, severe cases may require extraction of all incisor teeth.
Guinea Pigs – have continuously growing incisors and cheek teeth. The mandibular cheek teeth curve toward the tongue (lingual), the maxillary teeth curve towards the lips (buccal). As a result, overgrowth of the lower cheek teeth (may be secondary to incisor problems or poor diet) can entrap or traumatise the tongue, making it almost impossible for the guinea pig to eat. Overgrowth of the upper teeth can result in severe soft tissue trauma and pain. Treatment requires a short anaesthetic to allow good oral access and the overgrown teeth are shave back to as normal a level as possible. Repeat treatment may be required monthly (or more/less frequently) depending on the patient.
If you have any suggestion for future FAQs, please email info@petdentalservices.com.au
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