Discussion

Detailed examination of the erupted dentition and supporting gingival tissues is an indispensable aid to investigations into dental disease and frequently provides key information that can assist in the diagnosis and management of a variety of conditions. The excellent image quality afforded by oral endoscopy, and the facility to both project and record images is unparalleled and promises to revolutionise many aspects of equine dentistry.
Arguably the greatest impact of the advent of oral endoscopy has been on defining of the spectrum of 'normal' and pathological findings within the mouth. Previously, our understanding of conditions of the equine mouth was derived largely from post mortem studies, under which circumstances there is inevitably a dissociation between pathology and clinical syndrome. With the routine use of oral endoscopy we now have the ability to thoroughly and objectively document the state of a patient's mouth (without relying on the subjectivity inherent in dental charts), assess it in relation to clinical signs and monitor progression or regression of disease and response to treatments. Longitudinal tracking of conditions ranging from abnormal patterns of dental wear to diastemata, tooth malalignment and peripheral caries has previously not been possible yet it is precisely this information that is needed to fully understand these dynamic pathologies. Recognition of what is 'normal' is a prerequisite to diagnosing and treating 'abnormal'.
Oral endoscopy is commonly employed in cases presented for suspected dental infection. Key abnormalities that are strongly indicative of dentoalveolar infection include 'open' pulp chamber/s, focal gingival recession (+/- purulent drainage into oral cavity) and discolouration of the clinical crown. These abnormalities are usually subtle and demand a detailed and systematic endoscopic examination of the occlusal, buccal and lingual/palatal aspects of the entire dental arcade in order that they do not escape detection. The importance of such a thorough inspection cannot be overemphasised, as it is not uncommon for oral endoscopic findings to be the deciding factor in the management of a case over and above other imaging modalities including radiography and computed tomography. Open pulps are not invariably clinically relevant but when present can add to the body of evidence that might incriminate a particular tooth. Focal gingival recession with purulent discharge is pathognomonic for dental infection.
Oral endoscopy also has a role in the work-up of cases presenting with oral discomfort. Detection of diastemata, gingival pocketing and traumatic lesions of the soft tissues of the oral cavity may be of relevance and should be interpreted in the context of the clinical syndrome being investigated. Diastemata can be cleaned of trapped food under endoscopic control and severity of gingival pocketing fully assessed using probes. The location of soft tissue traumatic lesions in relation to adjacent teeth can be used to guide prophylactic work; traumatic ulceration of the caudal soft tissue pillar (adjacent the mandibular '11s) is a good example of a lesion that may elude inspection aided by dental mirror. Cheek tooth malalignment meanwhile is often a complex condition and endoscopy permits characterisation of inter-tooth relationships, tooth angulation (both mediolateral and rostro-caudal) and associated focal overgrowths, facilitating a structured approach to remedial procedures that takes account of the dynamic nature of any eruption disorder.
The role of oral endoscopy has expanded beyond simple diagnostic utilisation however and endoscopic imaging is now routinely used to assist treatment procedures. With appropriate facilities technically challenging tasks can be undertaken even deep in the oral cavity with considerable precision in the standing, sedated patient. Diastema widening inherently involves some risk of direct or thermal damage to vital pulp horns, yet with constant visualisation during the procedure this risk becomes negligible; quite aside from the safety aspect the quality of work achieved with endoscopy greatly exceeds that of 'blind' widening. The filling of carious infundibular cavities also lends itself well to endoscopic control. But it is in the area of cheek tooth removal, and particularly the most challenging extractions (such as those involving fractured or fragile teeth, or deep apical fragments) that oral endoscopy has really proven its value. Good visualisation permits accurate placement of probes alongside dental tissue in order to break down periodontal attachments; this eliminates the usual reliance on forceps-assisted movement of available tooth crown and lowers the risk of further fragmentation. Although time-consuming, extraction of fractured teeth using oral endoscopic guidance has a high success rate (approaching 90%) that is comparable to traditional oral extraction of intact cheek teeth.
It is perhaps entirely predictable that the inaccessible nature of the equine oral cavity should encourage the development of diagnostic and treatment applications for oral endoscopy. Growing appetite for minimally-invasive, standing surgical procedures is likely to prompt further advancement in this field: future equine dental techniques, both remedial and surgical, will assuredly be more elegant, precise and efficacious than those that have been used to date.