Crossley-Studien

• Crossley, DA: Blood testing chinchillas. In: Vet. Rec. 1998 Mar 21;142(12):316 - Link
• Crossley, DA et al: Caries and odontoclastic resorptive lesions in a chinchilla (Chinchilla lanigera). In: Veterinary Record 1997;141:13 337-339 - Link
  

Summary:

It is well recognised that domesticated chinchillas (Chinchilla lanigera) suffer from a range of dental problems, the most frequent of which is the result of reduced and uneven coronal wear of the premolar and molar (cheek) teeth with resultant root elongation and secondary malocclusion (Crossley 1995 + 1997). Although rarely detected clinically, destruction of dental hard tissue can often be recognised at post-mortem and in prepared skulls. This paper reports the histological confirmation of caries and odontoclastic resorptive lesions in a chinchilla.

• Crossley, DA: Clinical aspects of rodent dental anatomy - In: J Vet Dent, 12(4):131-135, 1995 - Link

Summary:

The order Rodentia is vast, encompassing a large number of species with significant anatomical variations developed during natural adaptation to differing habitats. Many veterinarians have little knowledge of the a natomy of species other than the commoner domestic large herbivores and small carnivores. Clinicians require a basic knowledge of the relevant anatomy of species they are likely to be asked to treat. This article provides sufficient working knowledge of the oral and dental anatomy of those rodents commonly kept as pets to enable veterinarians to interpret clinical and radiographic findings when investigating suspected dental disease.

• Crossley, DA: Dental disease in chinchillas. In: Vet. Rec. 1997 May 10;140(19):512 - Link; Inhalte online nicht mehr verfügbar, Zitate aus Degupedia:
  

  Zitat :

  Realising that premolar and molar tooth elongation was significant, Kennedy (1952) attempted to increase tooth wear by the addition of pumice powder to pelleted rations. This had little if any effect on the incidence of "malocclusion", presumably the short duration of chewing when fed pelleted rations was insufficient to increase tooth wear significantly.

  Zitat :

  A recently performed small-scale investigation (Kupzac 1997) provides useful observations on the feeding behaviour of caged chinchillas when they are given a typical diet of hay and pelleted food, the proportion of feeding time devoted to eating hay being significantly greater. The effect of increasing the proportion of hay is likely to be two fold, firstly increased tooth wear due to the greater time chewing and, secondly, a reduction in boredom as a greater proportion of waking time is devoted to feeding.

  Zitat :

  As most chinchillas receive at least part of their diet as commercially produced pellets which are supplemented with calcium, other essential minerals and vitamins A and D, and as very high vitamin D levels were present in most of the blood samples tested whilst the vast majority showed no disturbance of bone formation, nutrient deficiency is not likely to be a problem for most of the population. It is probable that wild chinchillas have suboptimum nutrient intake, and as a result, their teeth are not maximally mineralised. On the contrary, excessive intake is likely for the majority of captive animals. High vitamin D and calcium intake has been shown to increase bone and tooth mineralisation in several rodent species (Pitaru et al 1982, Buffenstein et al 1995) and the same would be expected of chinchillas. If this is the case, the teeth of captive chinchillas on commercial foods will be more resistant to attrition, compounding the effects of these poorly abrasive diets that require little chewing.

  CHAPTER 5: CONCLUSION

  This thesis has described the normal dentition of chinchillas and identified a wide range of dental pathology encountered in captive-bred chinchillas in the UK. A large proportion of otherwise apparently healthy chinchillas have dental abnormalities, confirming the initial clinical impression obtained by the author. These problems are primarily related to tooth elongation which has effects both intra-orally and within both the apical and periapical tissues. As disease is rare in the wild and common in captive chinchillas, dental disease is caused by factors occurring in captivity. The main factor appears to be the type and physical form of the diet, these being factors that have been shown to have a major effect on tooth wear in herbivores (Baker et al 1959, Walker et al 1978, Baker 1979, Rensberger 1973, Teaford 1988, Muylle et al 1999) and both eruption rates and lengths of incisor teeth in rodents (Michaeli et al 1974, Kiliaridis 1986, Brin et al 1990, Burn-Murdoch 1991 and 1993). Changes to the diet have dramatically altered human tooth wear patterns within a single generation (Andrews and Martin 1991) with consequent effects on occlusion (Waugh 1937, Corruccini and Lee 1984), so the more dramatic changes seen in chinchillas is not unexpected when the facts, i.e. that they have continuously growing teeth and theirdiet has changed from highly abrasive mountain vegetation that requires prolonged chewing to poorly abrasive lowland grown vegetation supplemented with medium to high energy processed foods that require little chewing, are taken into consideration. The form and physical properties of the food are particularly important for herbivores, affecting both chewing (Rensberger 1973, Weijs et al 1989) and tooth wear patterns (Baker et al 1959, Rensberger 1973, Baker 1979, Eisenmenger and Zetner 1985, Lowder and Mueller 1998). Chinchillas are adapted to feed on a diet of tough monocotyledonous vegetation that has a high phytolith content (Parry et al 1984, Lanning and Eluterius 1992). This requires prolonged chewing that, combined with the abrasive phytolith content, causes rapid dent alattrition, this rapid tooth wear being compensated for by continuous, equally rapid, tooth growth and eruption. Diets given to captive chinchillas are generally highly nutritious, easily chewed and poorly abrasive in comparison to a natural diet. This reduces the duration of chewing and minimises tooth wear whilst supplementation with calcium and vitamin D potentially increases the mineralisation of the teeth making them more resistant to wear. As a result, the teeth initially elongate, however, contact with the opposing dental arcade impedes further eruption. Whilst there is a wide latitude in the rate of growth and eruption of elodont teeth, the extremely slow or arrested eruption seen in many chinchillas is not matched by an equal reduction or arrest of apical growth. The elongating apical tissues intrude and become distorted, resulting in dysplasia of the newly formed dental tissues. Encroachment of the odontogenic tissues on the surrounding bone induces remodelling which results in ventro-lateral mandibular swellings and obstruction of lacrimal drainage in the maxilla, signs commonly detected in animals presented in veterinary practise. Tooth elongation also appears to be, at least indirectly, responsible for many other dental lesions such as interproximal food impaction, periodontitis and approximal caries.

  The tooth elongation seen in chinchillas with dental disease does result in a form of malocclusion, justifying the use of the term 'maloccluder' to describe affected animals. However, the malocclusion is of a type only commonly seen in herbivores with elodont dentition and it is not the primary problem, so use of a different term would be more appropriate.

  It appears that lack of dietary attrition is the most important factor in development of dental problems in captive chinchillas, the rate and pattern of progression varying depending on a range of cofactors including stress, nutritional imbalances and toxicities. Whilst a primary genetic aetiology is possible in some of the conditions encountered, such as congenitally missing cheek teeth (a problem identified in a single breeding line), it cannot be assumed for the other forms of dental disease. The failure of early breeders to reduce the incidence of "malocclusion" below 18% by eliminating affected stock from the breeding pool is not surprising as all chinchillas have the potential for developing dramatic tooth elongation when there is insufficient attrition, the commercial diets used were poorly abrasive and they only recognised a small proportion (18%) of animals as being affected, when it is likely that a much higher proportion were affected as the author recognised 35% of apparently healthy chinchillas as being affected on external examination, which fails to detect many cases.

  If these conclusions are correct, provision of a diet matching the consistency, form and nutritional content of that consumed by wild animals, which do not appear to develop significant dental problems, will prevent many of the dental problems encountered incaptive chinchillas. This is supported by the reported reduction in incidence of dental problems in a large-scale breeding unit that dramatically reduced the proportion of commercial chinchilla food in the diet, replacing it with hay. However, the possibility that specific genetic factors may be involved in the susceptibility of the captive chinchilla population to dental disease cannot be entirely ruled out as the original animals taken into captivity may not have been representative of the wild population.

  Testing the hypothesis that "providing the diet as minimally processed natural vegetation reduces the tendency for chinchillas to develop tooth elongation" would require a closely controlled study to eliminate as many variables as possible. It could be tested by keeping three groups of chinchillas under the same conditions, a control group receiving a traditional diet of pelleted rations supplemented with hay whilst feeding the test groups a balanced diet composed primarily of hay and other leafy vegetation supplemented with essential nutrients, one group receiving the food unprocessed and the other processed into a pelleted ration. In vivo direct measurement of dorso-ventral skull height (Figure 149) at set intervals might be accurate enough to provide an answer within a period of 12 months, however, a more accurate method such as monthly tooth length measurement, from lateral radiographs or following sacrifice of animals, would be expected to require a shorter period of study. Examination under anaesthesia and radiography or euthanasia would be required to assess the effects of the test diets on a wider range of dental pathology. Euthanasia of animals would also permit histological examination and accurate assessment of tooth growth and eruption rates.

• Crossley, DA et al: Dental disease in chinchillas in the UK. In: Journal of Small Animal Practice Volume 42, Issue 1, pages 12–19, January 2001 - Link
  

Abstract

Dental abnormalities are common in chinchillas, although knowledge of the lesions responsible for the clinical signs is incomplete. Animals bred in the UK were examined to gain further knowledge of dental disease in this chinchilla population. Dental abnormalities, particularly those related to tooth elongation, were detected on careful external examination of 35 per cent of apparently healthy chinchillas. Incisor abnormalities were seen on clinical examination in 55 per cent of chinchillas presented because of clinical illness. In all but one case, this occurred secondarily to crown elongation of the cheek teeth or to the absence of opposing teeth, rather than being a primary skeletal problem. Clinical signs commonly attributed to malocclusion, such as ventral mandibular swelling, weight loss, dysphagia, altered chewing pattern and changed food preferences, were not specific to malocclusion, being seen associated with coronal spike formation, root elongation and advanced periodontal lesions. Caries and resorptive lesions rarely caused clinical signs in this population, but were identified during 37 per cent of postmortem examinations. Congenital absence of teeth, skeletal malocclusion and pathological loss of teeth all resulted in significant clinical signs, but were rare. It is concluded that provision of a diet with physical properties more closely matching that of wild chinchillas should improve the dental health of captive animals.

• Crossley, DA: Dental Disease In Rabbits And Herbivorous Rodents - Online nicht mehr verfügbar, Zitat aus Degupedia:

Introduction
In first opinion small animal veterinary practice one is frequently presented with pet rabbits and rodents which have medical problems of possible dental origin. Unfortunately, for various reasons, many are not recognised as dental cases at an early enough, treatable, stage. Owners not infrequently fail to notice that small pets have a problem until death is imminent. Even when spotted earlier the problem may still have progressed beyond practical treatment. When signs of a problem are noticed early in the disease process, making a definitive diagnosis is often difficult, requiring costly investigation. As a result, investigation is often neglected. Both the owners' inability/ unwillingness to pay for treatment, and many veterinary surgeons' lack of enthusiasm and knowledge of the condition or species concerned, play their part. It is very easy when presented with a sick rabbit or rodent to prescribe a "standard" treatment regime and hope the patient will get better. Unfortunately this often just allows the condition to progress beyond the stage where correct treatment would have effected control or a cure.
The following discussion relates mainly to rabbits and the truly herbivorous pet rodents, guinea pigs and chinchillas, which have elodont premolars, molars and incisor teeth (The teeth continue growing throughout life).

Diagnosis of dental disease in rabbits and rodents.
To make an accurate diagnosis it helps to have sufficient data regarding the patient, its history and the signs observed. In most cases the history and an initial external examination of a sick animal will give indications as to any probable dental involvement.

Signs indicative of (probable) dental disease in rabbits and rodents:
In order of frequency of observation in the author's practice.

* significant
** very significant
*** extremely significant
**** specific dental problem

*** Weight loss
* Poor coat condition
** Digestive disturbance
*** Noticeable reduction in food intake
*** Dysphagia
*** Epiphora (**** chinchilla)
**** Visible incisor malocclusion/overgrowth
**** Palpable bony swelling of ventral mandible
*** Discomfort on palpation over cheek teeth
** Discomfort on manipulating jaw
*** Reduced range of movement of jaw
*** Inability to fully close jaw
** Conjunctivitis
*** Inappetance
**** Mandibular prognathism
*** Excessive salivation (slobbers)
*** Purulent ocular/nasal discharge
*** Facial abscessation
*** Mandibular abscessation
** Submandibular/cervical lymphadenopathy
*** Exopthalmos
* Systemic disease
** Emaciation
* Death

Oral examination
The long diastema between the incisor and cheek teeth of rabbits and rodents makes effective examination of the premolar and molar (cheek) teeth, along with their supporting soft tissues, difficult. Although it is possible to use an auriscope as an oral endoscope in some species, the restricted field of view means that many lesions will be missed. Even when examining a patient under anaesthesia using mouth gags, cheek dilators, mouth mirrors and magnification, it is common for experienced clinicians to miss significant oral lesions. In this regard, post mortem examinations are a very useful learning tool.

Common dental problems in rabbits and rodents
Unlike the situation in pet carnivores, periodontal disease is not frequently recognised in rabbits and rodents. This is probably mainly due to a lower incidence, but will also be due to a failure of many clinicians to detect or recognise signs of its presence.
The most frequently recognised dental problem in rabbits and rodents is malocclusion of their easily examined elodont (continually growing aradicular hypsodont) incisor teeth. Without the normal regular wear from chewing or gnawing activity, these non-functional maloccluded teeth continue growing, further impeding function.
The second most cmmon dental problem in the small herbivores is cheek tooth overgrowth. This often accompanies incisor malocclusion; either as a part of the primary condition, or as a purely secondary problem; but it is also seen as a primary problem in its own right. Cheek tooth overgrowth may result from lack of wear due to malocclusion or an insufficiently abrasive diet. It may also occur secondary to periodontal or metabolic (impaired collagen formation) disease. Whether or not the occlusion was normal to start with, a secondary malocclusion will develop as a result of tooth overgrowth. The exception to this last statement is when root extension occurs as a result of growth without matching eruption, as may sometimes be seen in chinchillas. In this case there may ocular signs, as described later, without any oral abnormality. In the author's experience, rabbits and guinea pigs do not develop root extension without visible oral signs of cheek tooth malocclusion or overgrowth.
Whether a malocclusion is primary or secondary, abnormal tooth wear of the naturally curved cheek teeth tends to cause development of sharp enamel spikes/spurs which irritate the cheeks and tongue leading to:

* pain
* dysphagia
* quidding
* salivation
* inappetance
* weight loss
* abscessation

It seems that root growth continues despite increased resistance to eruption following lack of adequate wear to the crown. Root extension frequently accompanies cheek tooth malocclusion. The extending maxillary root apices invade the lachrymal bone, obstructing the lachrymal duct and causing epiphora, and the orbit, leading to proptosis of the eye. The close proximity of the root apex of the rabbit's mesial cheek teeth to the lacrimal duct accounts for the occurrence of epiphora and the frequent spread of periodontal infection from these teeth to the tear duct, producing a typical purulent occular discharge.
Root extension of the mandibular cheek teeth leads to remodelling or thinning of the adjacent cortical bone with development of palpable swellings along the ventral surface of the mandible. Suspected mandibular or maxillary root extension is best confirmed radiographically.
Facial and mandibular abscesses quite common and are generally caused by dental problems, though infection of external wounds does also occur.
Dental abscesses may be due to:

* Periodontal infection
* Endodontic infection
* Orthodontic problems

In the latter case the abscess is usually due to a tooth penetrating the oral mucosa making localisation of the problem tooth easy.
Both periodontal and endodontic abscesses may appear away from the source of the problem. Endodontically affected teeth are best identified radiographically. Observation of periodontal food impaction or the location of periodontal pockets on careful probing may identify an offending tooth or teeth, but even so, radiography is still advisable.

Treatment options
As the vast majority of the orthodontic problems seen in practice seem to be hereditary, often with generation after generation showing the same problems, genetic counselling should be given to pet owners and breeders. Culling of affected breeding stock and their offspring is essential. Unfortunately by the time the problem becomes apparent, the affected animals have generally already produced several litters.
(How much genetic counselling do human patients get before orthodontic treatment is performed on them?) Depending on the situation the main treatment options in pets are:

* Benign neglect (not advised)
* Incisor tooth shortening
* Cheek tooth occlusal equilibration
* Extraction of affected teeth
* Euthanasia

Whilst benign neglect is a common practice, just maintaining observation for signs of pain or distress, this cannot be recommended. As already mentioned, any delay in investigation and treatment will allow further progression of the disease process reducing the chances of successful treatment.
The incisor tooth overgrowth problem has traditionally been managed by repeated tooth shortening (preferably trimming using a bur in a high speed dental handpiece), without investigation of the underlying problem. In cases with recurrent overgrowth, extraction of the offending teeth has been suggested as a more permanent solution. In early cases with a minor degree of rosro-caudal malocclusion, correction can occasionally be accomplished in rabbits (not rodents) by burring a reverse bevel on the mandibular incisors to create an incline plane like interlock with the maxillary first incisors. In the majority of cases, occlusal equilibration of the cheek teeth is also required.
Treatment of the cheek teeth by removing enamel spikes and occlusal equilibration is sometimes possible, though the long term results are poor in most cases. As with the correction of rabbit incisor malocclusion, the treatment is most successful if performed at an early stage, in mild cases. Dietary alteration (providing hay as the largest component of the diet) to increase the rate of attrition is highly beneficial in these cases. In more advanced cases the provision of a more abrasive diet is helpful, but it is usually necessary to repeat occlusal equilabration at regular intervals.
Whilst extraction of rabbits' incisors is useful in cases of malocclusion with recurrent overgrowth of these teeth, the long term results are disappointing in over 50% of cases due to the development of significant cheek tooth problems. Although it may not be visually obvious at the time of incisor extraction, most of the rabbits treated by the author have had radiographic changes suggestive of cheek tooth problems, even when everything appeared normal on oral examination. As would be expected, if there is concurrent cheek tooth disease (periodontal disease, malocclusion, overgrowth etc.), any improvement following treatment of just the incisor problem tends to be of short duration.
The treatment of dental abscesses in rabbits and rodents requires identification of the cause. If due to periodontal or endodontic disease, extraction of the affected teeth is necessary in addition to local treatment {drainage, curretage, application of a Ca(OH)2 dressing}. When the abscess is due to mucosal penetration of an enamel spike, removal of the spike, plus treatment of the underlying malocclusion will be effective.

Treatment policy
Due to the low value of most pet rabbits and rodents, the cost of investigation and treatment of dental disease is a significant factor to many owners. They want to know if it is worth having treatment. As a result, it is no longer the author's policy to immediately recommend treatment of dental problems in these animals, but rather to suggest a thorough examination and assessment under anaesthesia to see whether treatment is likely to be beneficial, and if so, whether recurrence should be expected. The biggest problem has been finding reliable prognostic indicators.
This approach has significantly increased the take up of dental services for these species from around 20% to 50% of cases. This still leaves half the affected animals. Of these, about half the owners opt for immediate euthanasia, whilst the other cases go onto a tooth shortening or benign neglect program.

Prognostic indicators
As mentioned previously, cheek tooth problems are an indication of a poor prognosis, but their presence or their full extent are often not identified on clinical examination. Radiology, whilst not being totally reliable, does seem to give a good indication of the extent and degree of cheek tooth problems. When the results of physical examination are combined with radiological assessment it is possible to formulate a more reliable prognosis.
Any severely debilitated patients are put onto a nursing care program prior to full assessment. Failure to respond to intensive care indicates a grave prognosis. In these cases where there is a very high anaesthetic risk, the choice is between euthanasia and an attempt at investigation and treatment. If such animals survive induction of anaesthesia treatment might be possible, so the attempt is worthwhile, though the majority die on induction, which is basically equivalent to performing euthanasia anyway.
If no serious problems are found during the definitive oral examination and the radiographs look OK, then treatment is usually worthwhile. Treated animals should be followed up. Re-examination and re-treatment should be arranged if signs fail to disappear, or if they recur at a later date.
If there are gross changes, abnormal root morphology, significant root extension, bone loss, osteomyelitis etc. then euthanasia is probably the most humane option.
Between the two extremes, the author treats those cases where the owner is keen to have a go and euthanases the others. Recurrence of signs in treated animals from this group is taken as an indication for euthanasia.

References

1. Brown, S.A. (1993). Incisor removal in the rabbit, TNAVC 1993 proceedings, pages 791-792.
2. Crossley, D.A. (1994). Extraction of rabbit incisor teeth, EVDS Forum 1993 no. 4
3. Harkness, J.E. and Wagner, J.E. (1989). The Biology and Medicine of Rabbits and Rodents, third edition, Published by Lea & Febiger, Philadelphia.
4. Kennedy, A.H. (1970). Chinchilla Diseases and Ailments, Published by Clay Publishing, Bewdley, Ontario.
5. Lobprise, H.B. and Wiggs, R.B. (1991). Dental and oral disease in lagomorphs, J.Vet.Dent, 1991:8(2)
6. Okerman, L. (1988). Diseases of Domestic Rabbits, published by Blackwell Scientific Publications, Oxford.
7. Richardson, V.C.G. (1992). Diseases of Domestic Giunea Pigs, Published by Blackwell Scientific Publications, Oxford.
8. Wiggs, R.B. and Lobprise, H.B. (1990). Dental disease in rodents, J.Vet.Dent, 1990:7(3)
9. Wiggs, R.B. and Lobprise, H.B. (1995). Dentistry in pet lagomorphs and rodents, in: BSAVA Manual of Small Animal Dentistry, second edition (Eds. D.A.Crossley & S. Penman). published by BSAVAQuelle: http://web.archive.org/web/20060907175425/http://periodont.spallek.com/peris9.html

 

• Crossley, DA (2010): Dental Disease In Rabbits And  Rodents - Link
• Crossley, DA: Haematology and serum biochemistry in chinchillas - Link fehlt inzwischen, abgespeicherter Inhalt:
  

SUMMARY
Blood testing is routinely used for health assessment in species for which normal ranges are known. Insufficient data is available for many exotic species including chinchillas. Chinchillas are susceptible to a wide range of disorders so blood testing is expected to be a useful clinical tool for this species. Although basic haematology parameters have been published, little work appears to have been done on serum chemistry. Blood samples were collected from clinically healthy and diseased chinchillas, and submitted to a commercial veterinary laboratory. Haematology and serum chemistry analyses were performed in order to furnish reference ranges and to assess whether such tests were of value in the early diagnosis of dental disease in chinchillas. Some parameters showed wide variations between animals. Variation was not found to be related to age, sex, a history of fur chewing or the presence of early dental lesions. High serum creatinine kinase levels occurred in animals which struggled during capture with other parameters varying most in animals with advanced diseased.

• Crossley, DA: Pathophysiology of Continuously Growing Teeth. In: Exotics conference, Ljubljana, 2005 - Link fehlt inzwischen ganz, abgespeicherter inhalt:
  

Conclusion
As elodont teeth are being formed throughout life anything (metabolic disease, teratogens, vitamin or mineral imbalances, natural and unnatural forces, trauma, inflammation and infection) affecting histodifferentiation, growth, maturation, matrix secretion or mineralisation will have the potential to cause of developmental dental disease at any age, whereas teeth of limited growth are minimally affected after their roots are formed. Lack of tooth wear is a major problem in domestic herbivores that are fed concentrate rations. In the case of those with continuously growing teeth this rapidly results in coronal elongation, increased occlusal contact and prolonged occlusal pressure with obstruction of eruption and knock-on consequences at the growing tooth apex. Apical changes affect the formation of tooth tissue leading to various forms of dysplasia varying from altered tooth curvature to gross disruption of tissue morphology. Clinically there are many complicating cofactors in the etiology of dental disease in elodont species. Herbivores are prey species and as such they are extremely susceptible to stress. Stress with resultant high serum cortisol levels appears to be a major factor influencing the rate of progression of disease. Nutritional imbalance, if severe, can cause dental changes, whilst a lesser degree of imbalance or deficiency has a similar effect to stress in increasing the rate of progression of changes caused by physical factors. A combination of more natural diet and environmental conditions would appear to be the most practical measures for reducing the incidence of dental disease in elodont herbivores.

 

• Crossley, DA et al: Skull size and cheek-tooth length in wild-caught and captive-bred chinchillas. In: Archives of Oral Biology, Volume 46, Issue 10, October 2001, Pages 919–928 - Link
  

Summary:

Chinchillas are herbivorous rodents with teeth that all grow continuously. In captivity they are commonly affected by dental disease. Since the range of dental disease occurring in wild chinchillas is unknown, the dentition of museum specimens originally obtained from the wild was assessed and compared with specimens prepared from captive bred animals.

 

Skulls from wild-caught chinchillas showed minimal evidence of dental disease and the teeth were all short, cheek tooth lengths averaging 5.9 mm. Cheek tooth lengths in zoo specimens (average 6.6 mm), clinically normal (average 7.4 mm) and captive bred animals with dental disease (average 10 mm) were significantly elongated by comparison (p < 0.0001). Captive bred specimens showed a wide range of tooth related lesions.

 

These results suggest that some aspect of captivity is responsible for the development of dental disease in chinchillas. It is suggested that the diet (its physical form and composition) is the main etiological factor, and that provision of a diet closely matching that of wild chinchillas should significantly reduce the incidence of dental disease in captive chinchillas.

 

• Crossley, DA et al: The site of obstruction of the lacrimal drainage system in Chinchillas (Chinchilla lanigera) with "wet eyes", 1999 - Link fehlt, Zitat aus Chinchillaclub:
  

Introduction:

A common clinical problem seen in chinchillas (Chinchilla lanigera) is "wet eyes" due to lacrimal overflow.

 

Aim:

To investigate the site or sites of obstruction of the lacrimal drainage system in chinchillas showing signs of lacrimal overflow.

 

Method:

Radiography, CT scanning, anatomical dissection, and histological examination of affected animals. signs of lacrimal overflow.

 

Results:

The main site of obstruction of lacrimal drainage is in the descending portion of the lacrimal canal between the orbit and the incisor tooth root apex. Bony remodelling around elongating maxillary premolar and first two molar tooth roots intrudes into the lacrimal canal compressing and sometimes occluding or even obliterating the lacrimal canal and duct. No evidence has been found for obstruction adjacent to the incisor root apices in the specimens examined so far.

 

Discussion:

Lacrimal drainage in healthy chinchillas is similar to that in other rodents. This species is adapted to a highly abrasive herbivorous diet, having continuously growing cheek teeth (in addition to the continuously growing incisors). When these teeth are not worn adequately, i.e. when domestic animals are fed commercial diets, the teeth continue to elongate. Eventually occlusal pressure prevents eruption, so the roots intrude inducing remodelling of adjacent tissue including the lacrimal canal.

 

Conclusions:

Chinchillas should be fed a herbivorous diet which requires prolonged chewing in order to wear the teeth adequately.

 

• Crossley, DA et al: Use of computed tomography to investigate cheek tooth abnormalities in chinchillas (Chinchilla laniger). In: Journal of Small Animal Practice 1998 Aug;39(8):385-9 - Link

Abstract

Computerised tomographic scanning was used to investigate tooth structure in chinchillas (Chinchilla laniger), both cheek tooth crown and root abnormalities being common in this species. This paper describes a common form of dental disease affecting species with continuously growing teeth, with particular reference to the chinchilla, and confirms the potential role of computed tomography (CT) in its early diagnosis. CT imaging is compared with previously available methods of investigation which frequently fail to detect early pathological changes.