Persistent primary teeth

23 Persistent primary teeth




INITIAL PRESENTATION


Persistent primary teeth and developing malocclusion.



PATIENT DETAILS


A 20-week-old, female, Yorkshire terrier.



CASE HISTORY


The owner was concerned that ‘she has too many teeth’. She had a poor appetite and would not eat anything other than grilled chicken, cut into small pieces. The case was referred to us for management.



ORAL EXAMINATION – CONSCIOUS


The dog disliked having her face handled. She was tiny (weight 1.8 kg) and difficult to restrain adequately. A cursory conscious examination was performed, which revealed the following:


1. Mixed dentition with numerous persistent primary teeth

2. Generalized moderate to severe gingivitis.


ORAL EXAMINATION – UNDER GENERAL ANAESTHETIC


A thorough oral and dental examination, including investigating periodontal parameters, was performed. All findings were noted on the dental record sheet.


In summary, examination under general anaesthesia identified the following:


1. Skeletal relationship
• The upper and lower jaw seemed to be of normal length and width for breed.

2. Persistent primary teeth
• The primary upper incisors were solidly (no mobility) in place and the permanent counterparts were erupted caudal to them (Fig. 23.1).

• The primary lower incisors had been shed and the erupted permanent lower incisors were occluding between the persistent primary and the permanent upper incisors (i.e. reverse scissor occlusion of permanent incisors).

• All four primary canines were solidly in place. The diastema between the third upper incisor and upper canine was filled by the permanent upper canine erupting in front of the persistent primary canine bilaterally (Fig. 23.2). The permanent lower canines were trapped medial to the persistent primary canines, and were occluding with and traumatizing the palatal mucosa.

• Persistent primary first premolars in all quadrants were causing crowding and rotation of the permanent successors.

3. Generalized moderate to severe gingivitis
• The gingivitis was most severe in regions where there were persistent primary as well as permanent teeth (Fig. 23.2).

image

Figure 23.1 Incisor occlusion. The permanent upper incisors were fully erupted caudal to the persistent primary upper incisors. The primary lower incisors had been exfoliated and the permanent counterparts were fully erupted and occluding between the rows of upper incisors.


image

Figure 23.2 Canine occlusion. The permanent upper canines were erupting in front of the persistent primary canine bilaterally, thus closing the diastema where the permanent lower canines should occlude. Note the severe gingivitis (reddening, swelling and spontaneous haemorrhage of the gingival margin).



FURTHER INVESTIGATIONS


Radiographs were taken of all persistent primary canine teeth (to determine the anatomy of the primary tooth, and the position and stage of development of the permanent counterpart).



RADIOGRAPHIC FINDINGS


The primary teeth were fully developed with closed apices. All permanent teeth were in early development (around half of total root length formed for incisors, around one-third of the total root length formed for the canines and around two-thirds of the estimated total root length for the premolars).

Related posts:

  1. The tooth and its periodontium
  2. Multiple tooth and jaw fracture
  3. Chronic gingivostomatitis as a consequence of periodontitis and iatrogenic injuries
  4. Enamel dysplasia

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Sep 3, 2016 | Posted by in SMALL ANIMAL | Comments Off on Persistent primary teeth

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