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Azerbaycan Saytlari

 »  Home  »  Endodontic Articles 2  »  Endodontic implications of the maxillary sinus: a review
Endodontic implications of the maxillary sinus: a review
Endodontic surgery.

Endodontic surgery in anterior teeth is usually carried out without hesitation, whereas in the posterior regions extraction is sometimes preferred. Amongst the reasons for extraction are the clinician’s lack of experience, the close proximity to the inferior alveolar nerve in the mandible and the extremely close relationship between the apices of the premolar and especially the molar teeth and the floor of the maxillary sinus in the maxilla (Gutmann & Harrison 1985, Skoglund et al . 1983). Oroantral communications may not necessarily be an iatrogenic event ( Jerome & Hill 1995). Pathological exposure of the sinus floor predisposes many surgical endodontic procedures to maxillary sinus communication (Selden 1989). Additionally, endoantral lesions may not always be radiographically evident preoperatively ( Jerome & Hill 1995).
The thickness of bone separating the apices of the teeth in the lateral segments of the maxilla from the sinus is shown to be in the range of 0.8–7 mm (Eberhardt et al . 1992). Perforations of the maxillary sinus following apicectomy of premolar and molar teeth in the maxilla have been reported by Ericson et al . (1974), Ioannides & Borstlap (1983), Rud & Rud (1998) and Freedman & Horowitz (1999). Ericson et al . (1974) found perforations in 18% of 159 premolar and molar apicectomies. Ioannides & Borstlap (1983) found 14.8% perforations from 47 maxillary molar apicectomies, Rud & Rud (1998) found 50% perforations in 200 cases of root resection of first maxillary molars and Freedman & Horowitz (1999) reported 10.4% perforations following 472 apicectomies on premolar and molar teeth.
The relative positions of the roots to the sinus are reported in several studies (Eberhardt et al . 1992, Killey & Kay 1967, Norman & Craig 1971, Von Wowern 1971). Killey & Kay (1967), quoting the results of anthropological studies by Von Bonsdorff (1925) reported the frequency of close proximity (0.5 mm or less) of roots of posterior maxillary teeth to the sinus floor: second molars 45.5%, first molars 30.4%, second premolars 19.7% and first premolars 0%. The distribution of oroantral communications amongst different groups of teeth in the studies by Ericson et al . (1974) and Freedman & Horowitz (1999) agreed well with their close proximity to the sinus floor reported by Killey & Kay (1967). Ericson et al . (1974) found oroantral communications in 7.7% of canines, 8.8% of first premolars, 26.1% of second premolars and 40% in molars, whilst Freedman & Horowitz (1999) found 23% perforations in molars, 13% in second premolars and 2% in first premolars.
Invasion of the maxillary sinus does not seem to result in permanent alteration of either the sinus membrane or its physiological function. Selden (1974) as well as Benninger et al . (1989) observed that the mucous membrane, complete with cilia, regenerate in about five months after total surgical removal. There is also agreement that the sinus membrane will recover from sinusitis once proper ventilation is restored (Stammberger 1986).
After apicectomy there will often be sinus mucosal thickening and signs of sinusitis that may either be attributed to the introduction of foreign material into the sinus at the time of operation or to persistent periapical infection (Ericson & Welander 1964, Ericson & Welander 1966, Ericson et al . 1974). It is thus of utmost importance that a meticulous technique be used to ensure that foreign material or the resected tooth apex does not enter the sinus ( Jerome & Hill 1995, Lin et al . 1985). Attempting to retrieve root tips, ground dentine and gutta percha debris from the sinus after apicectomy is difficult because of limited access and may cause additional unnecessary trauma (Jerome & Hill 1995). Since virtually all roots requiring apicectomy are associated with endodontic failures and/or periapical inflammatory lesions, their exclusion from the sinus is imperative. The buccal roots of upper posterior teeth in close proximity to the sinus can nearly always be treated without risk of perforation of the sinus. Barnes (1991) suggested cutting through bone and approaching the root from the front and below, never from above. He also suggested burring down of the apical part of the root to the desired level rather than resection owing to the risk of displacement of the resected tip into the sinus. However, in the presence of an existing sinus exposure, grinding the root to the desired level may create more debris than a single sectional cut and inflammatory tissue can be lost into the sinus during curettage ( Jerome & Hill 1995). Jerome & Hill (1995) described a method by which a hole is drilled in the root apex to secure the root tip with a suture before apicectomy, thus enabling the removal of the inflammatory lesion with the root tip. If a root tip is displaced into the maxillary sinus further management will be required as the likelihood of the foreign material being infected is high. A post complication radiograph is mandatory to identify and locate the object. Further management may include referral to a surgical specialist.
Repair of the bony partition between sinus and apex after root canal treatment or surgery will usually occur (Ericson et al . 1974). Ericson et al . (1974) found that only four out of 26 patients examined in their tomographic study did not show bony repair after apicectomy. In three of these cases periapical radiographs showed successful healing whilst the fourth case was classified as uncertain healing. These results indicate that in a small percentage of patients with sinus perforations bony healing may not occur following apicectomy, but it may not necessarily affect the healing of the sinus mucosa (Freedman & Horowitz 1999).
Watzek et al . (1997) found no significant difference in the healing rate between patients with and without intraoperative sinus exposure in 146 apicectomies. These findings were consistent with those of Ericson et al . (1974), who showed no difference between the results regarding treatment outcome of apicectomies obtained in the groups without and those with oroantral communications. In the same study the results of the operation in the oroantral communication group with ruptured sinus mucosa did not differ from those in the group with intact mucosa. Surgical treatment of maxillary teeth with periapical periodontitis refractory to conventional endodontic treatment is thus recommended, regardless of the anatomical relationship of the teeth to the maxillary sinus.
Jerome (1994) reported an unusual and rare case with a horizontal root fracture of the mesiobuccal root of a maxillary first molar. The source of the fracture was determined to be trauma from access or curettage during two Caldwell–Luc maxillary sinus procedures. This case points out the necessity to take a good medical and dental history and emphasizes the fact that sinus surgery itself may have endodontic implications.
Many clinicians have used stabilisers (endosseous endodontic implants) as an adjunct to dental treatment over the last few decades (Feldman & Feldman 1992, Frank 1967, Orlay 1964). Endodontic stabilisers are indicated in both anterior and posterior teeth when a more desirable crown/root ratio is needed to increase stability (Feldman & Feldman 1992). According to Feldman & Feldman (1992) certain anatomical structures should be considered during the planning of treatment. Although they stated that penetration into the sinus does not supply additional stability, they showed a case with sinus perforation with a stabiliser in a maxillary molar one year postoperatively with apparently no need for splinting. Benenati (1989) reported a case where a sapphire endodontic stabiliser in a canine tooth perforated the maxillary sinus. The patient complained of periodic foul smelling purulent drainage from her right nostril and occasional swelling of her right cheek. Because of its limited degree of radiopacity, the implant was not readily identifiable on the preoperative radiograph and at operation could only be resected using a diamond bur.
In some instances broken instruments and/ or filling materials in the maxillary sinus can only be removed by means of a Caldwell–Luc procedure (Bailey 1998, Bjørnland et al . 1987, Kobayashi 1995). The history of the Caldwell–Luc operation dates back to the last decade of the 19th century when Henri Luc of France and George Caldwell of the United States independently described the principle of eradicating disease from the sinus and providing counterdrainage into the nose (Macbeth 1971).
An incision is made either around the necks of the teeth or in the buccogingival sulcus approximately 2 mm above the mucogingingival junction extending from the canine eminence to the posterior maxilla. A releasing incision is usually performed to prevent trauma to the mucoperiosteal flap during elevation. The soft tissues are elevated superiorly in the subperiosteal plane to expose the lateral maxillary wall. The infraorbital nerve is identified and carefully protected. An opening into the sinus is created through the canine fossa region above the roots of the maxillary teeth or it may be created more posteriorly depending on the pathologic condition. Sinus mucosa removal is dictated by the extent of disease with healthy mucosa being preserved. If the sinus disease is severe, a naso-antral window may be created transantrally into the inferior meatus to establish dependent drainage (Bailey 1998, Gonty 1994).

The palatal root of molars.
The palatal roots of maxillary molars pose a special problem during endodontic surgery procedures. These roots are 50% closer to the sinus than they are to the palate (Wallace 1996), show apical communication with the sinus 20% of the time and are less than 0.5 mm from the sinus 40% of the time (Watzek et al . 1997). A deep palate offers long vertical lateral walls and improved access. A shallow palate not only presents visibility, incision and elevation difficulties, but palatal root access is further complicated by the proximity of the apices to the greater palatine vessels (Arens et al . 1998). A major concern with any palatal flap is its reapproximation and reattachment following surgery. The pooling of blood between the flap tissue and the bone may cause gravitational sag with ischaemia and sloughing (Arens 1998). Together with other difficulties such as limited opening, a flat or thick palatal vault, the proximity to major vessels and nerves and the fact that the palatal root of the maxillary first molar is the most common root displaced into the sinus, the transantral approach may be seen as a desirable option (Wallace 1996). This technique has been described and successfully used by several authors (Altonen 1975, Rud & Andreasen 1972, Wallace 1996). It involves the raising of a full mucoperiosteal flap, resection of the two buccal roots, followed by opening of the lateral wall of the sinus with a large bone bur (Altonen 1975). Drilling is discontinued as soon as the bluish periosteum of the sinus appears. The periosteum is carefully loosened from the edges of the opening, using a curved periosteal elevator. The opening is widened with a rongeur to a size of about 1 1.5 cm (Altonen 1975, Wallace 1996). The periosteum is loosened from the base of the sinus with a curved elevator and the palatal root tip is exposed, by removing the paper thin bone layer from its top with a concave chisel. The root is resected at the desired level, the root end is prepared with an ultrasonic retrotip and a root end filling is placed (Wallace 1996). Compared with the Caldwell–Luc procedure for sinusitis, which involves a large bony opening and a radical removal of the antral lining, the insult of sinus exposure from this form of endodontic surgery is relatively minor (Wallace 1996). Despite the favourable arguments for the transantral approach, potential complications cannot be overlooked (Wallace 1996). The most obvious concerns would be development of an oroantral communication or chronic sinusitis after surgery. Proper technique, careful manipulation of tissue and the recommended antibiotics and decongestants should minimize these complications (Altonen 1975, McGowan et al . 1993).