IMPACTED CANINES After we talked about impacted third molars, today we ll discuss about maxillary impacted canines in upper dental arch, how to manage these cases as a dental surgeon. You will study about them in oral surgery and orthodontic courses Importance of Canine : 1- Canine is an important tooth in dental arch because it form a critical function in occlusion, it is called Canine Guidance, they are the first teeth that touch when jaws close together, they guide the rest of the teeth into their proper position. 2- Canines are important in Smile, because they are placed at the corners of upper and lower dental arches Unfortunately, this important tooth is the second most common tooth to be impacted after third molars The prevalence of impaction or ectopic eruption of the permanent maxillary canine has been reported to range from 0.92% to 2.2%, of which 8% are bilateral impactions. Maxillary canine impactions are twice as common in females (1.17%) as in males (0.51%). In about 85% of these cases, the impacted teeth are located palatal to the dental arch, in the remaining 15% of cases, the impactions are located labially. There is some evidence that patients with Class II division 2 malocclusion and tooth aplasia may be at a higher risk to the development of an ectopic canine. Impacted canines occur 20 times more frequently in the maxilla than in the mandible. The reason behind high chance of impaction of canines is : 1- the delayed eruption : canine erupts after the lateral incisor and the premolar, so it is the last one to arrive and the adjacent teeth are already erupted so the existed space might not be enough for canine to erupt freely, it often has to put up with limited space. 2- the long path of eruption, because canine start to erupt from very high position near the eyes, from the canine fosse and postdam, that s why there is always the chance for upper canine mainly to get impaction The guidance theory of palatal canine displacement proposes that this anomaly is a result of local predisposing causes including congenitally missing lateral incisors, supernumerary teeth, odontomas, transposition of teeth and other mechanical determinants that all interfere with the path of eruption of the canine 1 of 0Page
Usually, the upper canines are the last of the ant teeth to erupt into place around age of 12, canine is considered impacted if it does not come into the mouth after the chronological age of their eruption NOW, WHAT CAN WE DO TO PREVENT IMPACTION!? the most effective treatmet is prevention, how? by the help of orthodontist and by the early management. The American association of orthodontists recommended at age of 8 to take OPG for the child and do orthodontic examination. They might interfere to do interceptive orthodontic treatment to create space or to do extraction by this they can prevent most of cases of impaction ( 70 95 % of cases ). At this age early problems and signs of impaction can be detected. What are the treatment options if we detect the impacted canines at age of 8? 1. Extraction of deciduous canines 2. Orthodontic Treatment to help canine to erupt by palatal expander if there wasn t enough space 3- Leave it : if the patient has good dental occlusion and there isn t any complain or pathology around this impacted canine so why I take it out! So, which is the best treatment option? It is Depend On The Case. Example : patient with age 50 years old visited you with good occlusion and nothing is pathological, we decided to leave it. But young patient with space in arch, orthodontic treatment is better Young patient with very high position of canine and orthodontist said that I cant push it down then the best is to extraction etc of cases SO THE BEST TEATMENT DEPENDS ON THE CASE. YOU HAVE TO STUDY EACH CASE WITH ORTHODONTIC DEPARTMENT TO DECIDE THE PROPER TREATMENT. BUT we said that the best treatment option was the early management and interceptive orthodontic treatment. Management : 1- Surgical Removal 2- Surgical Exposure by the help of orthodontist to pull the impacted canine back to its place 3- Leave and Follow- Up without any intervention 1- Surgical Removal Of Impacted Canines Indications : 1- Canine impaction may be associated with pathology like tumor or cysts and most commonly the Dentigerous cyst 1 of 4Page
2- it may affect adjacent teeth by pressure and cause resorption of adjacent roots such as upper lateral incisors roots or upper first premolar roots. 3- occlusion : when orthodontist prefers to extract to get proper one 4-. Dental implants or bridges : if there is impacted canine and difficult to orthodontist to push it down, but patient needs bridge or implant to replace the space, So the impacted canine must be taken out first because in if bridge is placed, in the future we will be worry about surrounded pathology, infection which damage the bridge. in case of implants, you have to extract because implant will take the place of canine. 5- Poor prognosis of ortho traction if : high position of canine, abnormal angulation, abnormal position like impacted canine between the roots of adjacent teeth. 6- Ankylosis: canines are ankylosed with bone and it can t be pulled out. You will need an extra pressure here to push it down orthodontically but this may causes protrusion of all the adjacent teeth and it still placed in its place with bone 7- Abnormal Anatomy like dilacerated root ( ninety degree angle between root and crown ) Example o Pathology indication to surgical removal of impacted canine due to Dentigerous cyst ( radiolucent lesion ) 1 of 3Page
Steps for surgical removal of impacted canines: 1- Location : the main first step, is it buccal or palatal? the start with LA and open the flap. Lets say the impacted canine was palatal and I open the bone from buccal side, it means I have to take out the flap of buccal soft tissue and I have to take out buccal cancellous bone to access the impacted palatal canine so how much damage you made! your access is wrong! So before you start your local anesthesia and before opening a flap. First you should decide the location; either buccal or palatal. Most of upper impacted canines are Palatal canine ( 75 % ), 25 % Buccal canine Although you can see the partially erupted canine and its prominent bulge, but you can t tell it s buccal or palatal location. Most of impacted canines are surrounded by sound bone so you might take parts or the whole of bone or do sectioning..etc You determine the location of impacted or partially erupted canines by and certain investigations must be done: 1-best investigation and accurate one 100% is 3D CT scan ( cone beam ) : I can see the canine from 3 dimensions to determine the exact location and it is the most accurate method though it is expensive 120,000 JD 2-Finger palpation : palpate the bulge, it s not always accurate 3-Angle of lateral incisor : if canine is located buccal to lateral incisor, it will push the crown palataly. so if the angulation of lateral incisor is directed toward the palate so Buccal canine, if it is directed outward buccaly so most probably there is palatal impacted canine. this in not accurate tech 4-X-ray ( OPG ) : not accurate to decide the location but it gives me idea about the position of adjacent teeth 5-Parallex technique : it was the old common investigation before CT scan, Two x ray radiograph with two different angles if canine is far ways opposite direction from path of x ray so it s located buccaly, if canine move within same path of x ray it is palatal -_- 1 of 2Page
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2- Let s say the canine is in labial position :start LA, open flap( raise mucosa with periosteoum), remove some bone, sectioning if needed, take it out, close the flap, do suture. Raise a mucoperiosteal flap either; 1. 3-sided flap: first incision on crest of the ridge with ant and post releasing incisions. It provides the best access and view. 2. 2-sided flap: incision on crest of the ridge and either ant or post releasing flap. 3-Gingival flap So Normal Surgical Extraction if the impacted canine is buccal canine 3- Let s say the canine is in Palatal Position : start LA, Open Flap The releasing incision is Contraindicated, we incise with the palatal cervical margins of teeth, If there is unilateral impaction such as right upper impacted canine start your flap mesial to upper right 6 to mesial of upper left 4 to prevent tension and tearing of flap when you raise it up If there are bilateral impacted canines ( upper right and left impacted canines ), start LA, open flap from upper right 6 to upper left 6 to maximize your access and extract them safely. 2- Surgical Exposure of impacted Canine Most of cases of impacted canine should be discussed by orthodontist and surgeon in the same time,because surgeon can decide that this tooth can be exposed but the orthodontist says no I can t and vice versa the same Indications : 1- This tooth should be evaluated by orthodontist and he says yes we can create space to do traction and push canine down 2- If orthodontist create enough space + the angulation of canine is not high + surgeon decide there in pathology,resorption, dilacerations + patient is willing to do orthodontic treatment So the final management is Surgical Exposure Surgical exposure : ( expose the crown by surgeon and traction by orthodontist ), sometimes the exposure itself without traction is enough to induce impacted canine to erupt because there is new school states that canine move by itself when it is exposed by surgeon. 1 of 6Page
Surgical exposure depends on location buccal or palatal Labial Canine Palatal Canine 1- Open Window Flap :start LA, do a circle (window) around it with blade to remove soft tissues and expose the crown but never go beneath the cemento-enamel junction, indicated if canine is uncovered 3 by bone. in window flap, we can remove from mucosa, cant remove from attached gingiva because if i remove attached gingiva and canine eroupts so it will covered by if imacted canine is in high up position so there is 2-3 mm of attached gingiva buccaly then i can do window. if impacted caine in lowe position, near to occlusal alveoar crest so we will cut attached gingiva near to crown so window is not indicated - open window in palate, remove soft tissue, remove bone, disadvantages : 1- you can't determine the site of palatal canine 100 %, not precise technique but it may be indicated if the crown edge of impacted tooth appeared 2- more bleeding from greater palatine vessels, you cant stop it but when placing the brackets the area must be completely dry raise a flap and suture it in high place to maintain tha attached gingiva round the canine, mucoperiosteal flap is raised and the orthodontist place bracket on the crown, then suture it back but on higher position apically this is called apical reposition flap the best one is : Full palatal Flap ex : if unilateral impaction, open flap from 6 to 4 to other side, expose crown, remove bone, then make window, close flap closed technique : open flap, expose crown, romove bone, the orthodontist put the bracket and the chain in the same session then suture the flap on its original place à this is called closed exposure 1 of 7Page
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3- Follow_UP o Nothing to do. o Follow up to prevent any farther pathology or infection or benign tumors or pressure on roots of adjacent teeth Complication of impacted upper canine surgical Extraction : and sometime the surgical exposure may cause injury to adjacent teeth 1- Trauma to adjacent teeth 2- Causes communication, ( ORO-NARAL & ORO-ANTRAL ) communication because the long root of canine reaches close to nose and sinus 3- Bleeding esp in case of palatal flap 4- Nerve injury in case of high releasing incision of buccal impacted canine flap so might reaches to infraorbital nerve, very rare 5- Fractures during extraction such as fracture in alveolar ridge when extraction of impacted ankyolised canine with bone and make extra pressure Other impacted teeth : we treat them by these previous methods ( removal exposure follow up ) same to impacted canine management Like : * supernumerary teeth ( incisors or premolars ) need extraction management ( surgical removal ) *impacted Lower five : either removal or exposure or follow up but take care about mental foramen. Good luck Shorooq Krishan 1 of 1Page