DENTISTRY DENTISTERIE

Dentistry on deciduous teeth: What, when, and how Loic F.J. Legendre

This article reviews the various procedures that should be performed on deciduous teeth. Too often problems with deciduous teeth are ignored and treatment delayed, resulting in serious conditions. Knowing what to do and when to do it can often correct problems before they cause damage. Pathology and treatment In dogs and cats, the deciduous teeth erupt between 3 and 6 wk (1) and are usually lost by the time the animal is 6 mo old. Therefore, these teeth are in use for an aver- age of only 4 mo. Nevertheless, deciduous teeth have their own set of problems, which require accurate and timely treatment. Figure 1: The left upper deciduous canine is fractured, Normally, a missing deciduous does not repre- exposing the chamber. sent a problem, but since the deciduous tooth gives rise to the corresponding permanent tooth, the adult tooth will also be missing (2). An intraoral radiograph quickly allows you to verify the presence or absence of the permanent tooth. One missing tooth is considered to be a developmental mistake. Several missing teeth, especially when bilateral, indicate a genetic involvement (3). A fractured deciduous tooth almost always presents with a pulp exposure (Figure 1). Leaving the fractured tooth alone and waiting for it to fall out usually results in a periapical abscess. The abscess, in turn, may dam- age the bud of the permanent tooth and progress to an osteomyelitis or a fistula. A timely extraction is the treatment of choice, but before you carefully elevate the ~~~~~~~~-Z.^....I tooth, take a radiograph to ascertain the position and pres- Figure 2: Following extraction, the site is flushed and left ence of the adult tooth bud. The maxillary and mandibu- unsutured to avoid creating scar tissue that would interfere with lar canine teeth are those most commonly fractured. the normal eruption of the adult tooth. The permanent buds of the teeth are located rostral (mesially) to the deciduous teeth, and the necessary to retrieve the root. Always warn the owner that no matter how permanent buds of the teeth are carefully the extraction is done, the located caudal and medial (distolingually) to the decid- adult tooth may be discolored, its enamel may be pitted, and it may be or even uous teeth. Therefore, when extracting a maxillary malpositioned, unerupted, have root dysplasia (3). After the been deciduous canine, you should be careful to avoid the ros- tooth has extracted, the area is flushed with an and tral surface of the tooth; similarly, when extracting a antibacterial solution the extraction site is mandibular canine, you should be careful to avoid the left unsutured (Figure 2). Oral antibi- mediocaudal surface of the tooth. Right-sized eleva- otics should be given postoperatively, if there is sign of tors and patience are required to successfully extract infection. deciduous canines. Elevation and rotation should be When the primary shows some abnormali- such as narrow or a gentle, avoiding extreme gouging. If you break the ties, base mandibular canines class II tooth, you should remove the retained fragment. (overshot), extractions need to be per- formed as soon as Sometimes a small gingival flap and osteoplasty are possible. In the above examples, the mandibular canines contact and damage the palate Westview Veterinary Services Ltd., 726-2601 Westview (Figure 3); this adverse interlock interferes with the Drive, North Vancouver, British Columbia V7N 3X4 growth of the . As the growth of mandible CanCanVeVet JJ-VolumeVoue3,Dcme-94935, December 1994 793 .. :...... s.

Figure 3: The mandible is short in relation to the Figure 5: The retained deciduous maxillary canine (black (brachygnathia). This causes the mandibular deciduous canines arrow) is forcing the adult canine (white arrow) to erupt ros- to penetrate the palate. The resulting holes are plainly visible trally. This narrows the space between the maxillary lateral on this picture. and the maxillary canine where the mandibular canine normally fits.

Figure 4: After the mandibular deciduous canines have been Figure 6: The retained deciduous mandibular canine (black removed, the animal is not traumatizing itself when it closes arrow) is displacing the adult canine (white arrow) to erupt cau- its , and its is able to grow, since it is no longer stuck domedially (distolingually). The mandibular canine ends up in position when the mouth is closed. damaging the palate because it is unable to flare laterally to clear the edges of the palate. and maxilla are not continuous or simultaneous, leaving deviation of their permanent counterparts, which results the mandibular canines in situ can result in a severe short- in (Figure 5,6). These teeth should be ening and bowing of the mandible. Extraction of the removed as soon as they are seen. They force the per- mandibular canines helps in two ways; it eliminates manent tooth bud to alter its eruptive pathway, and the damage caused to the palate (Figure 4) and it allows once disrupted, it rarely regains its normal position the growth of the mandible to attain its hereditary poten- (5). tial. In other words, an animal destined genetically to Deciduous dentistry is quite simple as long as one fol- have a short jaw will end up with a short jaw, but a nor- lows certain rules: always take a radiograph before mal mandible will end up growing fully. The sooner you proceeding, elevate as atraumatically as possible, and extract the damaging teeth, the greater the chance of end- warn the owner that there is a small risk that the per- ing up with a normal . For best results, extrac- manent tooth may be affected, no matter how careful you tion should be performed between 6 and 8 wk of age (cer- are. tainly before 12 wk); even then, correction of the bite is obtained in only 20% of cases. In most cases, you need References to extract the canines and of the shorter jaw to 1. Emily P, Penman S. Small Animal Dentistry, 2nd ed. Oxford: prevent further interference (3,4). The technique is the Pergamon Press, 1994: 4-5. same as described above. 2. Emily P. Adolescent dentistry. Proc Vet Dent 1991; 1 17-120. 3. Lobprise HB. Pedodontics. Proc Vet Dent 1993; 25-28. No two teeth of the same type should be at the same 4. Ross DL. Orthodontics for the dog. Vet Clin North Am Small place at the same time. Retained deciduous teeth cause Anim Pract 1986; 16: 939-954.

794 Can Vet J Volume 36, January 1995