Inferior Alveolar Nerve Transposition—An In Vitro Comparison Between Piezosurgery and Conventional Bur Use
An in vitro comparison between a new ultrasound-based piezoelectric device and a conventional bur was performed for lateralization or transposition of the inferior alveolar nerve to evaluate the effects on soft and hard tissue. Transposition of the inferior alveolar nerve was performed in the cadaver mandibles of 10 sheep: the left nerve was uncovered with a saline-cooled diamond-coated spherical bur (2000 rpm), and the right nerve was uncovered with the piezoelectric device mounted with a spherical diamond tip. The surface, the zone of bone defect, and the nerve were examined by light microscopy and laser microscopy. Bone treated with the rotary bur showed significantly smoother surfaces and shallower defect zones (50 μm) in comparison with the piezoelectric device (150 μm). Lesions of the epineurium and an increased amount of bone particles were found in the lesions prepared with the piezoelectric device. In vitro preparation with the piezoelectric device was more invasive to the bone than was a conventional diamond bur. Touching the inferior alveolar nerve resulted in roughening of the epineurium without affecting deeper structures. The degree of injury was lower than when using the conventional rotary bur.Abstract
Four cross sections of cadaver sheep mandibles were performed. From left to right: control, laser surface measurement, cracks, decalcification
and 3. Figure 2. UBM images of calculated, polynomially transformed surface. (A) Surface of original bone. (B) Bone surface after preparation with the rotary bur. (C) Bone surface after preparation with the piezoelectric device. Figure 3. Histological photomicrographs demonstrating the surface of bone fragments (decalcification group) (hematoxylin and eosin, magnification ×100). (A) Edge of original bone. (B) Edge of bone cut with rotary bur. (C) Edge of bone cut with piezoelectric device
Histological photomicrographs of the prepared alveolar bone edge stained en bloc with basic fuchsin. Stained areas appear orange under green epifluorescence (magnifications ×100 and ×200). (A, B) Bone edge prepared with the rotary bur. Smooth cut bone surface with few isolated cracks. (C, D) Bone edge prepared with the piezoelectric device. Irregular cut bone surface with loosened hard substance
Histological photomicrographs of the inferior alveolar nerve (IAN) sections. Nerve touched by the thin bent spatula during preparation with the rotary bur. (A) IAN cut lengthwise to the fascicles in the posterior part (magnification ×100). (B) IAN cut crosswise to the fascicles in the anterior part (magnification ×25). (C) IAN cut crosswise to the fascicles in the anterior part (magnification ×100). Nerve touched by the insertion of the piezoelectric device. (D) IAN cut lengthwise to the fascicles in the posterior part (magnification ×100). (E) IAN cut crosswise to the fascicles in the anterior part (magnification ×25). (F) IAN cut crosswise to the fascicles in the anterior part (magnification ×100)
The moment the piezoelectric insert touches the nerve. Proportions were retained (enlargement ×25)
Contributor Notes
Marc C. Metzger, MD, DDS, is a resident, R. Schoen, MD, DDS, is an assistant professor, and R. Schmelzeisen, MD, DDS, is chairman professor in the Department of Oral and Maxillofacial Surgery, University Hospital Freiburg, Albert Ludwigs University Freiburg, Freiburg, Germany. Address correspondence to Dr Metzger at Department of Oral and Maxillofacial Surgery, University Freiburg, Hugstetter Strasse 55, D-79106 Freiburg, Germany (Marc_Metzger@gmx.net).
K. H. Bormann, DDS, is a resident and N. C. Gellrich, MD, DDS, is chairman professor in the Department of Oral and Maxillofacial Surgery, University Hospital Hannover, Medical University, Hannover, Germany.