Assessment and Correlation of Dental Vitality and Blood Flow After a Le Fort I Osteotomy

Abstract

Statement of the Problem: This is a prospective, controlled study evaluating the effects of the Le Fort I osteotomy on dental pulpal blood flow (PBF) and pulpal vitality (PV) of maxillary incisors. Maintaining adequate blood supply to the mobilized segment following Le Fort I osteotomy is essential since the anterior maxilla and incisors are at greater risk for vascular impairment because of their greater distance to the palatal pedicle. Sensory nerves to the maxillary teeth are severed also during Le Fort I osteotomies. Sato et al (2003) suggested that the teeth with highest PBF following Le Fort I osteotomy had the quickest return of PV to baseline values. The purposes are: 1) assess the effects of a Le Fort I osteotomy to maxillary dental PBF and the correlation with PV, 2) determine and compare the short-term and long-term effects of Le Fort I osteotomy to dental pulpal blood flow and vitality. Materials and Methods: The study was conducted at UCSF Medical Center by the Department of Oral & Maxillofacial Surgery. Consecutive patients undergoing a Le Fort I osteotomy between July, 2003 to October, 2004 were enrolled. IRB approval and consent to participate were obtained. Laser Doppler flowmetry (Periflux, Stockholm Sweden) was used to measure PBF of right and left maxillary lateral and central incisors (0 indicated no blood flow). PV was assessed by responsiveness to sensory testing using an electric pulp tester (range 1-80; 80 indicated no sensation). Patients completed a pre-surgical dental PBF and PV assessment and post-surgical evaluation at 1-week, 2-week, 4-week, 3-month, and 6-month follow-up visits. Each patient served as his or her own control. Age, sex, and movement of maxillary segment data were collected. Method of Data Analysis: Pearson and Spearman correlation coefficients were calculated to measure association between blood flow, vitality, and movement of the maxilla. P values 0.05 were considered statistically significant. Results: Twenty-one patients enrolled in this study. A total of 83 teeth were evaluated. Mean age: 21.5 years; 15 females/6 males. The mean pre-operative and 1-week, 2-week, 4-week, 3-month, and 6-month post-operative PBF were 7.3, 7.1, 6.0, 6.0, 5.9, and 4.9 respectively. The mean pre-operative and 1-week, 2-week, 4-week, 3-month, and 6-month post-operative PV scores were 41.9, 77.2, 72.9, 73.7, 76.2, and 53.8 respectively. By the 6-month followup, 89% of the teeth had return of sensation (score less than 80). The mean maxillary advancement, impaction, lengthening (mm) were 5.3, 3.9, and 2.7 respectively. There was a statistically significant correlation between PBF at 1-week follow-up and PV at 6-month follow-up (P 0.02); the higher the PBF at 1-week follow-up, the more likely that PV score will remain high (with delay or no return of sensation) at 6-month follow-up. There were no other statistically significant correlations between PBF and return of sensation; there was a continued decrease in blood flow over time while the vitality returned. The maxillary movements did not significantly correlate with PV. However, the maxillary movements had variable effects on PBF. Greater maxillary impaction had a negative correlation with PBF, particularly during the 2-week and 1-month follow-up (P 0.0001). Greater maxillary advancement had a positive correlation with PBF, particularly during the 3-month follow-up (P 0.05). Conclusion: The Le Fort I procedure does not produce permanent PV deficits, with return of sensation typically by 6 months. There is continued PBF even immediately after maxillary osteotomies. Interestingly, PV returns with time regardless of the progressive decrease in PBF over time. There is no statistically significant correlation between PBF and PV except that high PBF noted during 1-week follow-up may negatively effect the PV at 6-month follow-up. Though maxillary movements did not correlate with PV, there was a variable effect on PBF particularly with greater impaction of the maxilla which detrimentally affected PBF.