Conventional Coronectomy vs Coronectomy in Combination Vital Pulp Treatment Using Calcium Silicate ?: A Randomized Controlled Trial up to 1 Year

The surgical removal of mandibular third molar teeth is one of the most frequently performed oral surgical procedures. One of the complications might occur during surgical removal of these teeth is injury to inferior alveolar nerve (IAN) which may lead to altered or loss of sensation to lower lip, chin, teeth and gingiva on the operated side. The risk for IAN injury may not be avoidable, even though the surgery was performed by an experienced surgeon and the positional relationship between the mandibular third molar and IAN was assessed accurately prior to surgery.

Pericoronitis, dental caries and periodontal disease are the most common pathologies associated with mandibular third molar teeth. Theoretically, removal of crown part of the teeth with a vital pulp and leaving the roots behind might be adequate to relive clinical symptoms arise from these pathologies. This technique was first described by Ecuyer and Debien in 1984 as coronectomy to prevent injury in case of close relationship of mandibular third molar with inferior IAN.

As shown previously in randomized clinical trials, fewer complications in terms of post-operative pain, IAN deficiency and dry socket were observed after coronectomy. Systematic reviews have confirmed that incidence of IAN injury was lower with coronectomy when compared to total removal in case of the lower third molar radiographically closely related with the IAN. Nerve injury was reported to occur in up to 20% of cases temporarily and 1-4% of cases permanently after total extraction, whereas 0-5.5% of cases temporarily after coronectomy.

Radiographic assessment using panaromic radiographs is the first step for coronectomy procedure. Presence of the interruption of the white line of the mandibular canal wall, darkening around the root(s), diverging of the mandibular canal, narrowing of the mandibular canal, narrowing of the root(s) and deflection of the root(s) are the indicators of increased risk for IAN injury. In recent years, cone beam computer tomography (CBCT) scanning is widely used method for further investigation to demonstrate the three-dimensional relationship between the tooth and IAN. Additionally, eligibility of the third molar for coronectomy should also be evaluated to be free of caries, pulpal inflammation and abnormal surrounding tissue. Coronectomy is contraindicated for non-compromised patients with good healing potential due to medical conditions such as diabetics, long-term steroid use, chemotherapy or radiotherapy.

One of the possible complications after coronectomy is migration and eruption of the roots left in the bone. Bone formation over the retained roots is expected to avoid eruption of these roots in the oral cavity. In case of eruption, remaining roots should be extracted. Another possible complication is periapical lesion development due to necrosis of the pulp. With conventional coronectomy procedure, no pulp treatment of the remaining roots is performed. Previous in vivo studies demonstrated that pulp retained vital after coronectomy. However, presence of pain and infection after coronectomy was reported in randomized clinical trials. Vital pulp treatment of the remaining roots with a bioactive material may have the potential to enhance both dentin and bone formation leading to reduced complications related with periapical inflammation and tooth migration.