Sensory change after implant surgery: related factors for recovery

Abstract

Objectives: This retrospective study aimed to analyze data on nerve damage in patients who complained of sensory changes after dental implant surgery, the clinical results according to proximity of the implant fixture to the inferior alveolar nerve (IAN) canal, and the factors affecting recovery of sensation.

Materials and methods: The electronic medical records of 64 patients who had experienced sensory change after implant surgery were reviewed. Patients were classified by sex, age, implant installation sites, recovery rate and the distance between the implant fixture and IAN canal on computed tomography (CT). The distance was classified into Group I (D>2 mm), Group II (2 mm≥D>0 mm), and Group III (D≤0 mm).

Results: The 64 patients were included and the mean age was 57.3±7.3 years. Among the 36 patients who visited our clinic more than two times, 21 patients (58.3%) reported improvement in sensation, 13 patients (36.1%) had no change in sensation, and 2 patients (5.6%) reported worsening sensation. In Group II, symptom improvement was achieved in all patients regardless of the removal of the implant fixture. In Group III, 8 patients (40.0%) had reported symptom improvement with removal of the implant fixture, and 2 patients (33.3%) of recovered patients showed improvement without removal. Removal of the implant fixture in Group III did not result in any significant difference in recovery (P=0.337), although there was a higher possibility of improvement in sensation in removal cases.

Conclusion: Clinicians first should consider removing the fixture when it directly invades the IAN canal. However, in cases of sensory change after dental implant surgery where the drill or implant fixture did not invade the IAN canal, other indirect factors such as flap elevation and damage due to anesthesia should be considered as causes of sensory change. Removal of the implant should be considered with caution in these situations.

Keywords: Adverse effects; Dental implant; Inferior alveolar nerve; Prognosis; Sensation disorders.

Fig. 1

Distance (D) between the implant fixture and the inferior alveolar nerve canal. A. Group I (D>2 mm). B. Group II (2 mm≥D>0 mm). C. Group III (D≤0 mm).

Fig. 2

Comparison of the recovery period between Group II and Group III. A significant difference was found on Fisher’s exact test (P=0.005), and the tendency for earlier recovery was found in Group II. (Group II: 2 mm≥D>0 mm, Group III: D≤0 mm, D: distance between the implant fixture or drilling location)

Fig. 3

Comparison of the recovery rate of Group III between removal and non-removal of implant fixtures. A significant difference was not found on Fisher’s exact test (P=0.337), but there was a higher possibility of improvement in sensation in removal cases.