The oral cavity comprises the lips, mucosal tissues, tongue, teeth and periodontal structures supporting the teeth. All of these must be visually assessed by the veterinary nurse (VN) or veterinary surgeon (VS) to identify any pathology while the animal is conscious, noting anything suspicious or abnormal on the clinical records.
This conscious assessment is the first stage of the process because the VN or VS will most likely make initial contact with the client and patient during a consultation. If a problem is suspected or pathology has been identified, reassessment of the oral cavity visually and via the use of instruments once the animal is anaesthetised, coupled with diagnostic imaging, is then essential. All of the findings from assessment under anaesthetic should be recorded on a dental chart, and the VS can then use this information to decide on a treatment plan (Holmstrom et al, 2004).
The actual process of probing and charting is not just the remit of the VS; an appropriately trained VN can be designated to the task of performing this thorough oral assessment. This can only serve to improve VN knowledge regarding oral nomenclature and terminology, tooth and root morphology, and the correct identification and quantification of pathology.
General anaesthetic
Figure 1 is an example of an adult canine dental chart, where the patient's details are recorded in the boxes in the top left-hand corner of the paper. A good chart will have open mouth views of the dental arcades as well as lateral views of the teeth and a rostrocaudal view, as pictured. All of the teeth for the species will be listed somewhere near the pictures provided, with room to write the findings associated with each tooth next to it. It will also have pictures of different types of occlusion that can be circled, a key to completing the dental chart, a tick list of treatments or interventions performed, and space to make additional notes, such as the start and end of surgical time, and anything noteworthy that is associated with the mucosae of each arcade (Baxter, 2013). As technology advances it may become common-place to complete electronic versions of dental charts.
In order to assess the oral cavity thoroughly so that no pathology is missed, the operator must have a good light source available. Figure 2 shows an example of a good quality light source which facilitates this, while saving floor space by virtue of being wall-mounted.
A mouth gag is essential for allowing easy access to the oral cavity for assessment purposes. It is recommended that a 2 ml syringe with the plunger removed and the hub cut off is used for dogs (Figures 3a and 3b), whereas a needle cap with the closed end cut off is very useful in cats. Spring-loaded metal mouth gags are not recommended, especially in cats, as they have been identified as a potential risk factor in the development of cerebral ischaemia and blindness. They are thought to be related to maxillary artery compromise and optic nerve damage, respectively; they create a wide gape, often for prolonged periods of time during surgery (Benney, 2017).
An air-driven dental unit is required, including an air/water syringe as pictured in Figure 4a. It is ideal if the unit has both a distilled water bottle and a brown/amber bottle containing a chlorhexidine-based solution attached (Figure 4b). Chlorhexidine is a broad-spectrum antiseptic with the ability to bind to oral tissues with good substantivity, which means it is effective for a period of around 12–14 hours (Cappelli and Mobley, 2008).
In the absence of a chlorhexidine-based solution that would typically be used for surgical skin preparation in other areas of the body, an oral rinse formulation is required. The chlorhexidine solution should be used to cover all surfaces within the oral cavity as a surgical preparation. This will help to reduce the aerosolised bacterial load during scaling. Chlorhexidine is sensitive to light, so this solution should always be placed in the brown/amber bottle (iM3 Inc, 2008), and the concentrate supplied by the manufacturer of the practice's dental machine should be used to ensure compatibility, following their guidelines for correct dilution.
Before probing and charting, and scaling and polishing, the operator and any assistants should don safety goggles to prevent ocular injury from debris (Figure 5). Operators should also wear non-sterile examination gloves throughout probing and charting for hygiene purposes. Whether they wear a face mask or not is the choice of the operator. Aerosolised bacteria is combatted via the aforementioned use of chlorhexidine oral solution; however the operator must be mindful of the chance of debris from the oral cavity and fluid splash-back entering their own oral cavity, which a mask would prevent. Similarly, scrub suits can be protected by wearing an apron.
There should be an ultrasonic scaler unit available because it is useful to scale the teeth prior to probing and charting (Figure 6). Depending on the level of calculus deposition, it might be difficult to access the gingival sulcus without this step (Baxter, 2013).
The operator needs to have access to the correct equipment to probe the teeth correctly and assess the enamel for any damage. This equipment should be sterilised between patients, and it is useful to have tins to hold the equipment together in a kit to help protect the delicate tips of the probe and explorer. Figure 7 shows such a tin containing a dental mirror, a dental probe with millimetre graduations, and a sharp explorer. Double-ended dental probes and explorers are also available.
A logical and systematic approach to the assessment of the oral cavity and dentition should be followed to ensure nothing is missed out. The operator should start by examining the lips, all of the mucosae, the oropharynx and the tongue, verbalising the location and nature of any abnormalities found to the person completing the chart. For example, ‘a buccal mucosal lesion adjacent to 208 measuring 3 mm by 5 mm’ is a description that would enable the operator to draw this onto the chart in the precise location, with a note of the measurements. This gross visual inspection could coincide with the operator dousing all of the surfaces with the aforementioned chlorhexidine solution.
Once this is complete, the operator should start to assess the teeth one by one, including assessment of the associated periodontal tissues. It is recommended to start at the central incisor of the first quadrant and work in a caudal direction, with the operator verbalising the findings for each tooth clearly so the person charting can record it accurately, for example:
This should be repeated for each of the four quadrants in turn.
Figure 8 shows the probe being held using a modified pen grip, which is the correct way to hold instruments to ensure they are used in a controlled manner. This grip also allows the ring finger to be used as a fulcrum for stability purposes. The probe is being inserted gently into the gingival sulcus of 204 at the mesial aspect of the tooth. When the operator feels resistance, it means the bottom of the sulcus has been reached by the tip of the probe and additional pressure in an apical direction should be avoided to prevent damage to the gingival attachment to the tooth. This depth can be measured against the millimetre graduations along the probe's surface.
Figure 9 depicts the probe in the sulcus closer to the distal aspect of the tooth. The probe has been gently ‘walked’ along the gingival sulcus in a mesial-to-distal direction, checking the probing depth along the way. This needs to be repeated along the palatal side of the tooth so that the sulcus has been checked around the whole tooth circumference.
Figure 10 shows the same process being undertaken on 206, with the probe being walked along the gingival sulcus to assess the probing depth.
Figure 11 shows the sharp explorer being used on the cusp of the crown to check the enamel surface for any defects. This includes the exploration of chips, for example, which are often located at the tips of the cusps. Figure 12 shows the explorer being turned at 90° to the way it was being used to probe the gingival sulcus. This is being done to check the furcation, the area between the roots of multirooted teeth; 206 has two roots and the furcation should be filled with alveolar bone so the probe should not be able to pass into or through the furcation area in healthy teeth. The furcation/s should be checked for all multirooted teeth. Figure 13 shows the explorer being used to check the 206 furcation from the palatal aspect as well. The operator must remember to check all sides/surfaces of the teeth.
In Figure 14, the operator has moved back to assess the upper fourth premolar, 208 in this circumstance, which is often called the upper carnassial. This is a triple-rooted tooth and has a mesiobuccal, mesiopalatal and a distal root. It is important that the operator understands the root morphology of all teeth to be able to assess them thoroughly. The operator in this picture is checking the depth of the gingival sulcus.
Figure 15 still concerns 208, and the operator is using the probe to check the furcation between the mesiobuccal and distal roots from the buccal aspect. Figure 16 depicts the operator using the probe to check the 208 furcation between the mesiobuccal and mesiopalatal roots.
Figure 17 shows the operator using the probe to check the 208 furcation between the mesiobuccal and distal roots but from the palatal aspect this time. In Figure 18, the operator is using the probe to check the 208 furcation between the mesiobuccal and mesiopalatal roots but from the palatal aspect this time.
Figure 19 shows the operator using the dental mirror to assist viewing and subsequent assessment of the palatal surfaces of these upper teeth. This is an invaluable tool in performing a thorough assessment, especially where visualisation of all surfaces is problematic.
Figure 20 shows the operator using the sharp dental explorer to assess the occlusal surface of 109, the first premolar of the opposing upper quadrant. The operator is provided with the ideal opportunity to visualise and check these opposing occlusal surfaces, and it is important to remember to check these areas for any signs of caries, also known as tooth decay.
Figure 21 shows a handheld dental x-ray machine; wall-mounted x-ray machines and floor models (on wheels) are also available. Owing to a large proportion of each tooth being embedded in bone and therefore not being visible to the naked eye, radiography is an essential tool to use once probing and charting have been completed.
Radiography can help the VS to assess the extent of periodontal disease (for example, horizontal, vertical and furcational bone loss levels and periapical pathology), as well as checking for abnormal root morphology and the extent of fracture lines that appear to extend subgingivally, or to investigate discoloured teeth (Niemiec, 2010; Baxter, 2013). These are but a few indications for the use of radiography to assist in the VS’ diagnosis, treatment planning, and surgical interventions, and the use of radiography should be recorded on the dental chart. Dental radiography, of course, is governed by the regulations associated with standard radiographic equipment in veterinary practice, so the usual health and safety precautions should be observed.
Ideally a digital radiography system would be available, for example the direct-to-digital setup depicted in Figure 22; this stores all of the images on the computer, making retrieval of the images very easy.
The alternative is using non-screen dental films and processing them manually in rapid developer and fixer solutions, all contained within a chairside dark room as shown in Figure 23. These film images are equally useful; however the operator must wait for them to completely fix and then dry before they can be safely archived.
The dental chart should be completed at the start of the procedure when probing and charting occur, then referred back to throughout the procedure. It should also be updated throughout the procedure as treatments are performed. For example, when a tooth has been extracted, the operator should verbally confirm this and the person completing the chart should cross that tooth out. Figure 24 shows the dental chart of a patient mid-procedure:
Conclusion
A logical and systematic approach is essential to the thorough assessment of the oral cavity and teeth therein, and the instruments should be used with care and precision to ensure accurate assessment of defects and to prevent trauma. Probing and charting are relatively straightforward once the operator is used to the recognised tooth-numbering system and is knowledgeable about what is normal and also how may roots each tooth should have; proficiency comes with time and practice.
Probing and charting is not just a task for the VS; an appropriately trained VN is more than capable of undertaking this procedure and thoroughly assessing the patient's oral health. However, the subsequent diagnoses and decisions regarding treatments will always be the remit of the VS. Dental charts are an important medico-legal document, providing contemporary documented evidence of the pathology identified and therefore justification of the treatments performed. As such, they should be completed accurately and stored securely for future retrieval alongside any other evidence of the oral pathology deemed necessary to retain, such as photographs or film radiographs.