The Dentist
Feline odontoclastic resorptive lesions (FORL) are the most frequent dental lesions present in cats. During oral examination, FORL is evident by loss of dental tissue on the crown or at the neck of teeth. The lesions are often covered with gingiva, typically more inflamed locally. The crown may be completely resorbed and the retained root covered by gingiva.
FORL may affect the root first, particularly on canine teeth. When this is the case, an early indicator may be a bulbous periodontium. Such a lesion may grow unnoticed until the crown falls, leaving the gingiva inflamed and the alveolus filled with a partially resorbed root.
Touching a FORL may elicit a pain reaction (quiver of the jaw), even when the patient is under general anesthesia (light plane). If many teeth are affected, the cat may hyper-salivate and rub his lips excessively. The feline’s mood and behavior may also be affected. Appetite may decrease, as well as the level of physical activity. The cat sleeps more and may become irascible. These changes, usually attributed to the animal aging, often disappear after successful treatment of the dental disease.
Resorptive lesions are classified from I to V according to their severity. Beyond this classification, primary root resorption is either internal or external.
 Class I: enamel only.
 Class II: enamel and dentin.
 Class III: pulp exposure.
 Class IV: extensive structural damage.
 Class V: the crown is completely resorbed, roots are retained.
FORL cause pain and loss of tooth function and may have adverse local or systemic effects. Osteomyelitis is a possible local complication encountered after loss of the crown of a canine tooth when the root is left untreated. This author has seen cases of osteomyelitis (that were confirmed by histopathologic examination of periradicular bone) associated with partially resorbed retained root tips from canine teeth.
Dental and periodontal diseases have been linked to systemic diseases. According to current scientific thought, seeding of bacteria and bacterial endotoxins in the blood stream is not the only pathological process involving oral disease in the pathogenesis of systemic diseases. A hypothesis considered very favorably by the medical community is that inflammation mediators released from oral infections may play an even greater role in causing systemic diseases.
In this context, the treatment of oral disease in feline patients with systemic diseases such as diabetes and hyperthyroidism could help us more efficiently control these diseases. These are usually older patients who have poor oral health with many resorptive lesions. It is important to consider treating oral disease in these patients’ global treatment plan.
No one has yet identified the etiology and pathogenesis of FORL. The cause may well be multi-factorial. The incidence of the disease is much higher today than it was in the 1950s. The effect of the advent of commercial diets, change in food texture, nutriments, and diet acidification to control feline urologic syndrome are all factors concerning alimentation that should be studied. Hypervitaminosis A or a diet high in calcium and low in phosphorus has been shown to increase the incidence of FORL. A diet higher in fiber, favoring chewing behavior, has decreased plaque formation and calculus build-up in zoo animals.
Viral infections and vaccination should also be regarded as possible contributing factors. More animals are now vaccinated against more diseases. Presence of viruses has been associated with oral inflammation. The incidence of Calicivirus infection is higher among cats with oral inflammatory disease than in the general feline population. Cats with immune system deficiency caused by infection with FIV or FeLV often have chronic oral inflammation, although most cats with FORL test negative for these two viruses.
Other contributing factors to the development of resorptive lesions in cats are the anatomy of the teeth, frequent vomiting, and forces exerted on the teeth during mastication. The anatomy of feline teeth in itself predisposes them to the development of resorptive lesions. Cats that vomit frequently have higher prevalence of FORL, caused by the effect of gastric acid on dental tissues. Physical forces exerted on the teeth during mastication may lead to abfraction, a flexural stress exerted on the buccal or lingual surface of the tooth associated with the development of resorptive lesion in humans.
Periodontal disease is present in most animals affected with FORL. The presence of bacterial plaque and the response by the host immune system cause the release of inflammatory factors responsible for resorption of bone and teeth. With cats, it would appear that cement and dentin are more readily resorbed than alveolar bone.
Association between FORL and periodontal disease as cause to effect has not been proven. Even if inflammatory cells are present in most FORL, they are not necessarily present at the beginning when the lesion is still covered with healthy gingiva. The inflammatory reaction may be a consequence of the development of the FORL, instead of its cause. The rough surface of the FORL increases attachment of bacterial plaque and calculus, leading to gingival inflammation.
Depending on whether periodontal disease is considered the cause or consequence of resorptive lesions, its control could either prevent its development or slow its progression. The control of the progression of periodontal disease is based on yearly oral examination and teeth cleaning and an oral home care regimen.
The diagnosis of resorptive lesions is based on an examination of the teeth using a dental explorator and oral radiographs. All the teeth should be included in the radiographic survey. There is an average of 3.1 lesions per affected cat. The lesions are drawn on the dental chart and a treatment plan is made.
Most teeth affected with FORL should be extracted. Restoration has little chance of success except on very early lesions (Class I or early class II). Restorative materials used are Glass ionomer (fluoride release) and dental composite. The surgical extraction of affected teeth gives the best prognosis. Dental extraction of feline teeth is not easy because their roots are long, thin and diverging. Teeth affected with resorptive lesions are more fragile and often ankylosed to the alveolar bone.
Prerequisites for a surgical extraction are a preoperative dental radiograph, appropriate dental equipment, and time. Extraction of teeth on cats necessitates dexterity, good technique, and patience. After the condition of the affected tooth is determined on a dental radiograph, the best strategy for its extraction is decided. The important points to evaluate are how much resorption is present and on what part of the tooth, is the root ankylosed or curved, is there a swelling (hypercementosis) at the apex of the root, what is the risk of fracturing the root or the jaw or displacing a root tip in the nasal cavity, sinuses or mandibular canal, etc.
A simple extraction technique is sufficient for incisors and upper molars. All other teeth are usually extracted surgically. With surgical extraction, a surgical blade (No. 15, 11 or 12) is first used to incise the attachment of the gingiva to the tooth. A mucoperiosteal flap is elevated with a periosteal elevator (Molt No. 9, Goldman-Fox No. 14, Cislax EX7 or EX9) to expose the alveolar bone. If the tooth has more than one root, the crown is sectioned with a high-speed hand-piece and a bur (FG No. 1 or No. 699) to create sections of crown each attached to a root.
A part of the alveolar bone on the buccal aspect of the root is removed with a bur. Each root is mobilized by stretching the periodontal ligament with a dental elevator (301S, Cislax EX5, EX15, EX 16, Winged Elevators). The blade is introduced between the root and the alveolus and each movement of rotation is maintained for at least 10 seconds. Only once the root is mobile should the extraction forceps be used to complete the extraction.
A post extraction radiograph is taken to confirm that the extraction of each root is complete. The alveolar bone margin is smoothed, the alveolus curetted and rinsed with sterile saline, the edge of the flap trimmed, and the flap sutured with absorbable material and a simple discontinuous pattern.
When a root fractures, the apical fragment can usually be retrieved after removal of more cortical bone and elevation with small root tip pick elevators. What should be avoided is to displace a root fragment into the mandibular canal, nasal cavity, or maxillary sinus. A bur may be used to pulverize a root fragment under direct vision and radiographic evaluation. If a root fragment is left in place, the owner should be informed and provision made for radiographic follow-up. It is important to mention that in case of a gingivo-stomatitis, it is essential that no root fragment be left at all.
Crown amputation with intentional retention of the roots is a controversial procedure. The only indication where this author thinks crown amputation should be used is for the treatment of ghost roots, where the root shadow is almost indistinguishable from the alveolar bone on the radiographs. Even then, the amputation site should be curetted to remove as much root tissue as possible.
Surgical extraction of many teeth affected with FORL is a lengthy intervention. It might be advantageous to consider a two-step procedure to shorten the length of time a cat is under continuous anesthesia (i.e., two shorter periods instead of a long period) and to allow surgical procedures to be made on healthy gingiva. The lack of time, equipment, or expertise available should never compromise the success of the treatment. It is better to reschedule or refer the case if it is in the best interest of the patient.
During the first step, the scaling, polishing, and examination of the teeth is done (and the intra-oral radiographs taken if the equipment is available). After definitive treatment planning, the second step involves doing the surgical procedures including extractions. The length of time between the two steps is typically two to four weeks. Because the patient is anesthetized for a shorter period each time, the body temperature and the blood pressure stay closer to normal values.
The age of the patient should not be considered an obstacle to proper professional dental care. Many preventive measures help safely anesthetize these patients: preoperative blood work, an anesthetic protocol adapted to the patient’s health status, anesthetic monitoring, intravenous fluid administration, a lower anesthetic plane required when using peri-operative analgesia (opiates, NSAIAs, regional anesthesia), etc. High-risk patients would benefit from having a veterinary anesthetist or internist available on-site.
Basic Practical Techniques in Tooth Extraction By John Robinson United Kingdom
Tooth extraction can be very challenging and is rarely a simple procedure. A successful extraction is when the entire tooth is removed with the minimum of trauma to the adjacent, remaining tissues (and the operator). To achieve the best success rate requires:
ROOT MORPHOLOGY
The operator needs to be familiar with the normal shape and number of roots of all the teeth. Be aware that abnormalities such as extra roots or abnormally shaped roots (e.g., hooks) are not uncommon. For a reminder of what is the normal root pattern, refer to a dental textbook, Dentalabels®, dental charts, Visimodels®, or a dry skull.
SECTIONING—MULTI-ROOTED TEETH
In the cat and dog, the routine technique for extraction is to loosen (luxate) and extract (elevation) each tooth root individually. In all cases, the crowns of 2 and 3 rooted teeth need to be sectioned to produce single root pieces prior to extraction. The roots of multi-rooted teeth are usually divergent and therefore have different paths of withdrawal. Using a dental drill to section the crown enables cutting that is accurate, quick, and causes minimum trauma to adjacent tissues.
The first step is to locate the furcation, which is generally directly below the main cuspal point of the crown. To confirm the location, it can be felt with a probe as a concavity or seen by slightly reflecting the gum margin with an instrument or the air syringe. The tooth should be cut from the furcation at gum level and up through the crown using a fissure bur in a dental handpiece. The cut may need to then be extended below gum level to achieve complete crown division. Test the division by wedging an elevator between the sectioned crown and observing slight movement of the crown parts in opposite directions. It may be helpful to also reduce the crown height prior to luxation.
Sectioning 3 rooted teeth (upper carnassial teeth and the upper molar teeth in dogs) can only be achieved by using fissure burs in dental handpieces. Accurate positioning of the cuts requires proper knowledge of tooth morphology.
Usually the crowns are sectioned by vertical cuts. In large teeth the crown height may be greater than the bur length. In these teeth, it is better to angle the cut to go through a part of the crown of less height. This also means the cutting requires less effort.
CUTTING THE GINGIVAL ATTACHMENT
As part of the severing of the tooth’s attachment, the gingival attachment of the tooth should be cut around the entire circumference. This can be done by running a scalpel blade around the gingival sulcus/pocket and cutting down the root surface to crestal bone. The gingival attachment can also be cut using a sharp dental elevator at the time of luxation. If the gingival attachment is not cut there will be unnecessary disruption and trauma to the soft tissues as the tooth is extracted.
ROOT LUXATION AND REMOVAL
Luxation is the loosening of the tooth in the socket by progressive severing of the periodontal ligament fibres. A Couplands elevator of the appropriate size, or a similar instrument is used. The elevator is inserted behind the gingiva at an acute angle to the tooth root until it hits crestal bone. The instrument tip is now wedged between the root and bone and gently rotated (not levered) to move the tooth laterally. The pressure is built up gradually and then held for five seconds to stretch and break the periodontal fibres. The elevator is then relocated at different sites around the tooth and the procedure repeated until the tooth root becomes loose. Patience and controlled force are needed, not brute strength. The force should be applied as low down the root as possible when extracting teeth. Slipping, when using an elevator, is often because the tooth moves. You should support the jaw with your other hand and have a thumb and finger on either side of the tooth being extracted. Using the air/water syringe during extraction to rinse away blood and keep it at bay can be very helpful as it enables the progress of root luxation to be seen clearly.
ROOT ELEVATION AND EXTRACTION
In tooth extraction in dogs, the tooth can completely extracted using the elevator but usually it is simpler to finish the extraction using extraction forceps. The final periodontal fibres are broken by slightly rotating the root in the socket. As the roots of teeth in the dog are neither straight nor round in cross section, they will not rotate more than a degree or two. When the root will turn a little in both directions the forceps can then be used to pull the tooth from the socket. The beaks of the extraction forceps should fit the root and make a 4-point contact. The root should always be gripped as low down as possible to reduce the torque on the root and the risk of breakage.
In cat tooth extraction, the forceps can be employed earlier and to greater effect to luxate the tooth. Once the root is moving, the forceps can be used to rotate the tooth in the socket. Teeth roots in cats tend to be straight and circular in cross section and so allow greater rotation. Care should be taken not to crush the tooth with the forceps or to allow forces lateral to the long axis of the root. Feline tooth root apices are often bulbous. Once the root is quite loose it is withdrawn by “popping” the bulbous apex through the narrower socket above.
SURGICAL EXTRACTION OR OPEN EXTRACTION TECHNIQUE
A surgical extraction technique is indicated for removal of all canine teeth and root fragments. Some people prefer this approach for the extraction of multiple adjacent teeth. A surgical extraction involves raising a gingival flap and removing some bone to facilitate extraction. All veterinary surgeons should be familiar with a surgical extraction procedure. A description of this technique can be found in the BSAVA Manual of Small Animal Dentistry (2nd ed.) and other good texts.
ROOT “ATOMISATION” ( to “destroy”)
The idea is that the root is drilled out using high-speed dental drills. This is not a proper extraction technique and should only be employed as a technique of last choice. Root atomisation is frequently necessary for feline teeth roots with odontoclastic resorptive lesions when the root is ankylosed or resorbed. It is better to leave a small piece of root tip rather than over drill and cause damage to adjacent structures such as the inferior alveolar canal or the maxillary sinus. There is insufficient follow up information available to know whether this is actually an acceptable procedure.
TREATMENT OF THE SOCKET
Once the tooth has been extracted, the aim is to promote the best healing of the socket. Sharp bony projections and non-viable bone pieces should be removed. Any non-viable soft tissue should also be removed. The socket should be gently curetted to remove any granulation tissue. There are pros and cons for suturing the gingiva. It should be considered whether the suturing or packing of a socket aids healing and reduces postoperative pain or hinders these factors due to the extra tissue manipulation and the presence of “foreign” material. Suturing is indicated when there is excessive tissue mobility. Extraction sockets heal very well naturally and the author feels that minimal intervention is best. The best way to promote healing and minimize post extraction pain is by gentle and proper extraction techniques. The amount of postoperative pain correlates to the degree of trauma to the adjacent bone and soft tissues during extraction.
EXTRACTION COMPLICATIONS
Extraction may be made more difficult by root abnormalities (such as excess curvature or hooks) or root ankylosis. Complications usually result from incorrect technique or insufficient care in its execution and include:
Iatrogenic damage to adjacent tissues.
Fractured roots and remnant root tips.
Displaced root fragments, especially the palatal root or the upper carnassial tooth or in the cat, mandibular premolar roots.
Fistula, usually oronasal fistula, after extracting the upper canine tooth in dogs.
Jaw fracture.
Delayed or complicated healing.
Dry socket.
DRY SOCKET
This condition has not been well reported in animals. It is well recognized in people when there is a marked increase in pain about three days after extraction. It is associated with loss of the blood clot from the socket and exposure of the bony surface. It is thought to occur in animals, especially if excessive force was used during the extraction. The animal begins exhibiting signs of pain and possibly pyrexia a few days after the dental extraction. Treatment is with antibiotics. In people, the socket is cleaned and packed with an obtundant and antiseptic dressing.
WHEN CAN A ROOT FRAGMENT BE LEFT?
The ideal is to avoid the situation by correct technique. Unless the fracture is considerably below bone level, it may still be possible to remove the root remnant by further use of elevators or other instruments. A surgical extraction technique will allow the removal of root remnants deep in the bone. A root fragment cannot be left if it has associated infection or pathology ( Stomatitis in this case –sfl). It can be argued that the potential complication from leaving a small piece of root tip (which is not infected) is sufficiently small as to make the trauma of removal unjustified. This may be so but should not be used as a general excuse. A radiograph should be taken and the animal’s records clearly marked to indicate the position of the root fragment. Where possible a follow-up radiograph should be obtained to monitor in case of developing pathology. (the veterinarian should tell you whether he’s gotten all of the root out or not. Please ask him if he does not mention it. –sfl)
POST EXTRACTION CARE
The owner should be advised not to feed soft sticky food, which will pack in the sockets. Normal food should be fed and soft, not sticky, food only used if necessary. Usual oral hygiene should be recommenced immediately. Topical application of chlorhexidine preparations can be used for a short period if there is an objection to tooth brushing. Tough chew toys should be withheld for about a week when sutures have been placed
Analgesia (a.k.a. pain medicine –sfl) should be given prior to extraction(s) and additional follow up analgesia considered. The amount of pain will depend on the difficulty of the extraction, the number of extraction sites and the individual patient. A course of antibiotics is not routinely indicated after tooth extraction. Antibiotics should be used when there is a specific reason for their requirement. (Pain medication should be requested by you as your cat will be in pain –sfl)
EQUIPMENT
Ideally, extraction kits should be prepared and sterilized ready for each situation. Many of the instruments or the particular pattern of a certain instrument will be according to the personal preference of the operator. The author would use:
Basic Extraction Kit
1. Full dental drill unit (including 3 in 1 syringe).
2. Luxator (s) (size according to size of teeth).
3. Elevators. For dogs; Couplands No. 1 and No. 3. For cats; Super Slim elevators.
4. Tooth forceps (pattern 76N).
5. Gauze swabs.
Possibly supplemented by bone rongeurs and a suture kit.
Surgical Extraction Kit
1. Basic extraction kit.
2. Periosteal elevator (Goldman Fox or Molt).
3. Scalpel handle and No. 15 blade.
4. Tissue forceps.
5. Needle holders.
6. Resorbable suture material with a swagged on needle ( 4/0 chromic gut or Monocryl).
Surgical Extractions
Cecilia Gorrel United Kingdom
DEFINITION
“Surgical Extraction” is defined as a technique where a muco-periosteal flap must be raised and alveolar bone removed in order to remove the whole tooth root.
INDICATIONS
There are often alternative treatments to extraction. Alternative treatment is recommended for strategic teeth (generally, permanent canine and large posterior teeth) that have a healthy periodontal status. Treatment by extraction, however, is always preferable to leaving pathology untreated.
Common indications for surgical extraction include:
Periodontally sound upper and lower canines, which are affected by fracture or involved in a malocclusion.
Teeth that are affected by ankylosis.
Root remnants where the remaining root fragments are embedded deep within the alveolus.
Roots with bizarre morphology.
Multiple-rooted tooth that has no loss of crestal bone.
TECHNIQUE FOR SURGICAL EXTRACTION OF TEETH
Pre-extraction radiographs to check root morphology and get a more complete picture of the pathology necessitating the extraction are mandatory. Surgical extraction should be performed in a clean environment. So, periodontal therapy (supra- and sub-gingival scaling, root planing and crown polishing) should be performed before starting the extraction.
Upper Canines
An upper canine tooth will be used as an example for surgical extraction. Differences in extraction technique for other teeth will be highlighted.
Procedure:
Cut the epithelial attachment around the canine and extend the incision rostrally to the 3rd incisor (103/104) and distally to the 2nd premolar (106/206) using a No. 11 or No. 15 blade.
Cut a releasing incision at the rostral and distal ends of the initial incision to just beyond the muco-gingival line. Make the releasing incisions slightly divergent to ensure that the base of the flap is broader than the edge.
Use a “wax spatula” type periosteal elevator to lift the gingiva and mucosa from the bone overlying the canine root. Extend the releasing incisions if necessary.
To remove the buccal bone plate overlying the root, use an appropriately sized round burr with water irrigation/cooling. It is usually not necessary to remove bone to the apex, only to two-thirds of the root length. A size 2 or 4 burr is best for cats, a size 6 for dogs and size 8 for giant breeds. Water-cooling and irrigation is mandatory otherwise bone will be thermally damaged and a sequestrum may later form. Bone can readily be differentiated from tooth; bone has a grayish colour and bleeds, cementum/dentine is white and avascular.
Use the round burr to create a trough or gutter between the tooth root and the alveolar bone on the rostral and distal root surfaces. Try to remove bone and not drill into the root surface, or the tooth may fracture during elevation.
Place an elevator in one of the troughs and rotate the elevator along its long axis. This action will rotate the tooth along its long axis. The aim is to break down the palatal periodontal fibers and those of the root tip, but avoid levering the root tip into the nasal cavity. The elevator is rotated to stretch the fibers, and held for 10–30 seconds at a time, repeating each side until the tooth becomes loose, and can be easily removed.
The burr is used to smooth the edges of the alveolus. If the socket is filled with debris, this should gently be flushed out prior to closure. Ensure a clean clot forms in the socket.
The flap should be sutured over the socket, such that there is no tension on any of the sutures. If necessary, bluntly dissect the flap sub-mucosally towards the lip margin in order to gain more tissue. Ensure that the edge of the palatal mucosa is free by gently inserting the periosteal elevator between the bone and soft tissue. Use simple interrupted sutures and an absorbable suture material with a swaged on needle. Proper placement of releasing incisions should ensure that all edges at the time of repair are supported by bone. If it is not possible to fully close the flap without tension, then leave an opening, which will heal by granulation.
Lower Canines
The upper canines will be the teeth most often extracted surgically, but mandibular canines, if periodontally sound, will also require surgical extraction due to their wide root compared with the diameter at the cemento-enamel junction and the curvature of the root. Sound mandibular canine roots should only be extracted with good reason since the root accounts for 50% of the rostral mandibular bulk. Their removal, together with alveolar bone, considerably weakens the rostral mandibular ramus and fractures may occur. Endodontic therapy and restoration of a periodontally sound but fractured lower canine is preferable to extraction.
If using a buccal approach, care must be taken to avoid damage to the neurovascular bundle exiting the mental foramen while raising the flap. A lingual approach is possible but gives poor visualisation for the procedure. To preserve mandibular strength, remove as little bone as possible—just to the point of maximum root. It is possible to obtain small curved luxators to follow the root curvature and minimise the amount of bone removal required.
Upper 4th Premolars And Lower 1st Molars in The Dog
These teeth, if affected by periodontitis, are usually removed by sectioning and non-surgical extraction. But if the teeth are periodontally sound, then surgical extraction is indicated. The flap for the upper 4th premolar (108/208) extends from the middle of the 3rd premolar (107/207) to the distal edge of the 1st molar (109/209), with the releasing incision made from the distal end of the first incision. This avoids damage to the infraorbital foramen, dorsal to the 3rd premolar (107/207). The flap for the lower 1st molar (309/409) usually only needs to extend to the adjacent teeth, with the releasing incisions at each end diverging as they pass through the mucogingival line. Buccal bone can be removed to expose the furcation in order to section the tooth into its constituent root/crown units. Further removal of alveolar crest bone will facilitate entry of elevators into the periodontal space without interference from the prominent enamel bulge on these teeth. If ankylosis is present, most of the buccal bone plate will need to be removed. (Use caution when removing large amounts of buccal bone as the upper 4th premolar mesiolateral root lies against the infraorbital canal and the lower 1st molar root tips are adjacent to the mental canal.)
Feline Premolars
Historically, feline premolars have been every veterinary surgeons nightmare due to the ease with which they fracture during extraction. This leaves roots, with or without pieces of crown attached, which must be removed. Although it might be tempting to leave these roots and hope they will resorb or the gingiva will grow over them, this is negligent. Remaining tooth fragments may cause a great deal of pain and act as a source of inflammation, possibly resulting in stomatitis. (If any pieces of root are left behind, it is highly probable that the Stomatitis will not go away, that is why this is SO important. –sfl)
Feline upper premolars can usually be removed non-surgically, but if ankylosis is present, the surgical techniques described above can be used. In the mandible, a modified technique aimed at preserving alveolar bone is recommended. This method can be adapted to the removal of most feline multiple rooted teeth.
The technique is to raise a small gingival flap, both buccally and lingually, followed by the removal of just enough alveolar crestal bone to expose the furcation. A small round burr, size 2 usually, is used to make two cuts from the furcation at 45 degrees, one distally, and one rostrally. These cuts will remove the bulk of the crown leaving only a small point of crown on each individual root. The next stage is to use either a size 2 or size 4 round burr to remove the cancellous bone between the two roots. The depth should be the same as the root length, and in the mandible, not long enough to enter the mandibular canal. If in doubt, measure the distance on your radiographs. Each root is then only supported by bone on three sides and a small luxator or elevator can be eased into the space created by the burr and the roots can be loosened and removed.
Retained Deciduous Maxillary Canine Teeth
Surgical extraction can be indicated here due to the long narrow root that is prone to fracture if a non-surgical approach is used. Follow the technique as above for a permanent tooth but use care to avoid damage to the permanent canine.
Off to the Vets | Perfect Cat | Cat Jokes
|
