An injury of the inferior alveolar nerve (IAN) presents a rare but serious complication, which results in the emergence of certain neurologically sensitive aberrations (hypoesthesia, hyperesthesia, dysesthesia, and anesthesia) of temporary but of permanent nature, as well. Generally, it can be said that the prevalence of the temporary aberrations ranges between 0.41%- 8.1%, and the prolonged, i.e. permanent symptoms are rarer and range between 0.014%-3,6% (Valmaseda-Castellonet et al., 2001; Brian, 2004; Queral-Godoy et al., 2005). It is an interesting fact that when, risky” third molars (teeth whose roots are in a very close correlation with the IAN) are extracted, the prevalence of this complication is higher than 20%. When we talk about these injuries of the inferior alveolar nerve, it is concerning the fact that to certain percent with these cases a complete physiological and functional recovery of the nerve is not achieved and these patients are permanently affected by certain neurosensory aberrations (Cheung et al., 2009). Namely, the ongoing therapeutic modalities purposed for taking care of the neurosensory deficit (two surgical and two non-surgical) enable only limited improvement of the sensations, i.e. not always a complete rehabilitation is achieved of the developed situation (Leung et al., 2012). In order to reduce or minimize the present high risk of injury to the nerve, determined by an X-ray, some alternative techniques are described for extraction of the lower third molars. Some of these techniques have been confirmed and as such established in surgical practice, while others are subject to future, additional analyzes within the differently designed clinical studies.

At the Clinic for Oral Surgery this type of intervention was performed on the third mandibular right molar with a female patient, 38 years of age, who was referring that the extraction of the lower third mandibular left molar led to her having unpleasant sensations (paresthesia) for a longer period of time. After the radiographic evaluation for a possible collision of the roots of the third mandibular right molar with the mandibular canal, it was decided that coronectomy should be performed (Figure 1).

Figure 1 Panoramic image

2. With a round borer a buccal, occlusal and distal osteotomy was made i.e. the crown was revealed and an enamel-cement border was exposed. In this way an adequate access for cutting through the enamel- cement border in pulp was provided (Figure 2).

Figure 2 Surgical exposition of the crown

3. A lingual retractor must be placed throughout the procedure, because the lingual cortical lamina may be perforated by careless handling and additionally the lingual nerve may be at risk of injury. The vertical distance of the nerve from the distal lingual crest bone in a third molar region is 2,28-8,32mm, and the horizontal distance is 0,58-3,45mm. Using a fissure bur the crown of the tooth was separated directly under the enamel-cement border (Figure 3). Once the crown was completely cut, it was removed with a suitable tool and thus the possibility of mobilizing the retained root fragment was minimized. During the performance of this phase a continuous irrigation with saline is required and if noticed mobility of the root fragment, it should be removed.

Figure 3 Surgery of the crown

5. The operational area was closed primarily (Figure 4).

Figure 4 Placement of sutures

Whitaker D.D., and Shankle R.J., 1974, A study of the histologic reaction of submerged root segments, Oral Surg. Oral Med. Oral Pathol., 37: 919-935
http://dx.doi.org/10.1016/0030-4220(74)90445-9