In the dental specialty of endodontics, periradicular surgery is surgery to the external root surface. Examples of periradicular surgery include apicoectomy, root resection, repair of root perforation or resorption defects, removal of broken fragments of the tooth or a filling material, and exploratory surgery to look for root fractures. Symptoms may be due to infection in the periradicular tissue around a root-treated tooth, which can impede healing of the tooth after conventional root canal treatment. After removing the pulp, the aim of endodontic treatment is to seal the pulpal space to prevent further bacterial contamination and allow healing of the periradicular tissue. Success rates for root-canal treatment range from 47 to 97 percent; failures may be due to spaces in the root-canal filling, a root filling which is too short or a preexisting periapical lesion. Treatment options are nonsurgical root-canal re-treatment or periradicular surgery. Although accessing and cleaning the pulp chamber and canals would be easier with the former, it is contraindicated in some patients. The stages of periradicular surgery are:
Local anaesthesia Flap design Bone removal Curettage Apicectomy Retrograde preparation and filling Wound closure
Indications Periradicular surgery should be very considered where previous endodontic treatment has failed, and possible re-root treatment is the preferred option. If re-root treatment is not possible, will not correct the problem or patient factors prevent it, periradicular surgery is indicated. Anatomical deviations preventing access or preparation of canal, including root-canal calcification, pulp stones, severely curved roots, bifurcations, secondary roots, lateral canals, delta apexes, internal and external resorption resistant to conventional treatment and an incomplete apex, may prevent the complete cleaning and preparation of the canal. Procedural errors include the formation of ledges, perforation of the root or floor of the pulp chamber, extruded root filling material, file breakages, or underfilled canals. These are only indications for periradicular surgery if they cause persistent periapical radiolucency, swelling and pain. Exploratory surgery that identifies possible root fractures or perforations indicates periradicular surgery. A biopsy may be used in suspicious or non-healing lesions, or when a patient has uncharacteristic signs and symptoms in periapical areas.
Contraindications Several factors are considered before periradicular surgery is performed. Severe systemic disease poses the risk of poor healing after surgery. The patient's attitude towards surgery should also be taken into account. A tooth is unsuitable for periradicular surgery if it does not have a good periodontal support or coronal seal. It must have enough structure to support restoration. Filling the root canals of the tooth from the crown (orthograde root canal therapy) should be the first treatment option to resolve inflammation caused by the tooth. Periradicular surgery is only considered if the inflammation persists after conventional root canal treatment. A patient's oral hygiene must be considered; poor oral hygiene increases the risk of infection and impairs healing of the surgical site. The lack of appropriate surgical access to the site contraindicates periradicular surgery; cutting the gum near important anatomical structures, such as neurovascular bundles, risks permanent jaw numbness. Unusual bone structure and root arrangement of the tooth should also be considered. The surgeon's skill and experience, and the facilities available, should be considered.
Procedure
Assessment Assessment before periradicular surgery involves a thorough history and clinical exam, followed by special investigations. Clinical assessment considers a number of factors. Oral hygiene and overall dental condition indicates the patient's motivation for treatment and the tooth's restorative prognosis. Gum health is important to ensure optimum healing and appearance after surgery. Cortical bone thickness, regional anatomy, and root fracture or resorption indicate possible difficulties. Special investigations include radiography, vitality testing of adjacent teeth and an occlusal loading assessment. Radiography identifies disease presence, including periradicular pathology. A periapical radiograph is usually the radiograph of choice. When examining the tooth which will receive surgery, the quality of the root treatment and canal anatomy (sclerosed or missed canals) is noted. More than one radiograph may be required to indicate possible treatment success. The root filling should be optimal. The relationship of the tooth to neighbouring structures (the inferior dental nerve, mental foramen and maxillary sinus) or to adjacent roots must be noted, to anticipate operative complications and inform the patient. At least 3 mm of tissue beyond the apex of the roots should be radiographically assessed.
Anaesthesia and haemostasis Haemostasis is imperative during surgery to allow optimum visualisation. It is achieved preoperatively with a local anaesthetic. The anaesthetic's adrenaline targets the smooth muscle of arterioles by acting on the alpha adrenergic receptors. Haemostasis is continued throughout the procedure. The main methods are:
Topical epinephrine pellets Ferric sulphate, which forms a plug by agglutinating the blood proteins; however, it is cytotoxic and can cause necrosis of the oral tissues. Calcium sulphate mechanically blocks open vessels and aids bone regeneration. Bleeding in the bone is also affected by the local anaesthetic's vasoconstriction and topically-applied agents. These topical agents should be removed before closing the surgical site. When the flap has been sutured in position, haemostasis is maintained postoperatively. Digital pressure on a damp gauze controls bleeding and stabilises the flap. An ice pack is recommended (15 minutes on, 30 minutes off) for the first six hours.
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