Method: Quasi-experimental and repeated-measures study designs were used in this study. Twenty-six adults with normal hearing (17 females, 9 males) participated. ABRs were acquired from the study participants at 3 intensity levels (80, 60, and 40 dB nHL), 3 frequencies (500, 1000, and 2000 Hz), 2 electrode montages (ipsilateral and vertical), and 2 stimuli (NB LS CE-Chirp and tone-burst) using 2 stopping criteria (fixed averages at 4,000 sweeps and F test at multiple points = 3.1).

Results: Wave V amplitudes were only 19%-26% larger for the vertical recordings than the ipsilateral recordings in both the ABRs obtained from the NB LS CE-Chirp and tone-burst stimuli. The mean differences in the F test at multiple points values and the residual noise levels between the ABRs obtained from the vertical and ipsilateral montages were statistically not significant. In addition, the ABR elicited from the NB LS CE-Chirp was significantly larger (up to 69%) than those from the tone-burst, except at the lower intensity level.

MATERIALS AND METHODS: Over a period of 10 years (1989 to 1999), 34 patients with dentofacial deformities who had orthognathic surgery were reviewed; patients with cleft lip and palate or syndromes were excluded.

RESULTS: The mean age (range, 17 to 35 years) of the patients was 24.3 years and the ratio of female to male was 2.4:1. The predominant ethnic group was Chinese, with females (47.1%) forming the largest group. The main reason for seeking surgery was aesthetic improvement (41%). The majority of the patients had skeletal class III pattern (91%) and bilateral sagittal split osteotomy was the most common surgery done (82%). Postoperative complications were mainly paraesthesia/numbness (56%) and infection (15%). In long-term review, 2 (6%) patients had persistent numbness of the inferior alveolar nerve.