Biomedical subjects

Nicole Eggensperger

Publications and source records attributed to Nicole Eggensperger.

8 recordsLinked to original sources

PubMed2006

Changes in the volume and density of calvarial split bone grafts after alveolar ridge augmentation.

OBJECTIVES: One main problem occurring after bone grafting is resorption, leading to insufficient bone volume and quality, and may subsequently cause dental implant failure. Comparison of graft volume and bone density of iliac crest and calvarial transplants determined by animal studies demonstrates significantly lower resorption of bone grafts harvested from the skull. This paper is the first clinical study evaluating bone volume and density changes of calvarial split bone grafts after alveolar ridge reconstruction. MATERIAL AND METHODS: Bone volume and density were determined using CT scans and the software program Dicom Works in a total of 51 calvarial grafts after alveolar ridge augmentation in 15 patients. CT scans were taken in all 15 patients immediately after grafting (T0) and before implantation after a postoperative period of 6 months (T1). In five patients (26 calvarial grafts), a 1-year follow-up was performed (T2). RESULTS: A mean volume reduction of 16.2% at T1 (15 patients) and 19.2% at T2 (five patients) was observed. Bone density was high--about 1000 Hounsfield units--and did not change during the 1-year period. At the time of implantation, 41 transplants were classified as quality 1 bone and 10 as quality 2-3 bone. Grafting area and the technique used for grafting (inlay or onlay graft) did not affect the postoperative bone volume reduction. Generalized osteoporosis did not increase the resorption rate of calvarial transplants. CONCLUSION: Based on these findings, calvarial split bone grafts are a promising alternative for alveolar ridge reconstruction in dental implantology.

Adolescent↗

PubMed2005

Long-term changes of hyoid bone position and pharyngeal airway size following mandibular setback by sagittal split ramus osteotomy.

INTRODUCTION: The purpose of this study was to determine long-term changes in hyoid bone position and pharyngeal airway size after mandibular setback osteotomies. MATERIAL AND METHODS: Serial cephalograms of 12 patients who underwent mandibular setback surgery were evaluated preoperatively, at 1 week, 6 months, and 14 months postoperatively, and finally after an average of 12 years. RESULTS: A mean setback of 5.6 mm was associated with a posterior and inferior movement of the hyoid bone. At long-term follow-up, the hyoid bone adapted horizontally to a position about 1.6 mm more posterior than its preoperative location. Immediately after surgery, the length of suprahyoid muscles correlated significantly with skeletal movements: suprahyoid muscles shortened by 4 mm but started lengthening after 1 year. Thereafter, it tended to correlate with the change of hyoid bone position rather than with skeletal relapse. Following the initial decrease after surgery, the size of the lower pharyngeal airway remained almost unchanged. The upper and middle pharyngeal airway sizes continued to decrease over the postoperative period of 12 years, and ultimately were smaller than their preoperative sizes by about 1.5 and 3 mm, respectively.

Adaptation, Physiological↗

PubMed2005

Midfacial reconstruction using calvarial split bone grafts.

OBJECTIVE: To evaluate the success rate of free calvarial grafts for midfacial reconstruction, the relevance of soft tissue coverage, and the influence of radiotherapy. DESIGN: Retrospective analysis. SETTING: University medical center. PATIENTS: Fifty-six patients (27 tumor cases, 24 trauma cases, and 5 others) underwent bony midface reconstruction using calvarial grafts in the past 11 years. Half of the patients with tumor were additionally treated with radiation. INTERVENTIONS: A total of 95 bone transplants were used for reconstruction of the zygoma, orbit, and nasal bone. Graft survival and complications were evaluated. Grafts with total and partial soft tissue coverage were compared. The influence of radiotherapy in the tumor patient group was determined. RESULTS: Graft survival was 95.8%. One nasal dorsum graft was totally resorbed. Infection occurred in 9 cases, leading to only 1 total and 2 partial graft losses. The incidence of dysfunction of the eye due to globe malposition after reconstruction of the orbital walls was low. A correlation between radiation and transplant loss as well as between soft tissue coverage and graft survival could not be found. CONCLUSIONS: For midfacial reconstruction, it is not necessary to fully cover calvarial bone grafts by the surrounding soft tissue. Even in patients who will undergo postoperative irradiation, calvarial bone grafts are a reliable alternative in selected cases.

Adolescent↗

PubMed2005

Long-term changes of hyoid bone and pharyngeal airway size following advancement of the mandible.

OBJECTIVE: To determine long-term changes in hyoid bone position and pharyngeal airway size after mandibular advancement, including evaluation of the relationship between length of suprahyoidal musculature and skeletal relapse. STUDY DESIGN: A cephalometric follow-up study (12 years) of 15 patients who underwent mandibular advancement surgery. RESULTS: The final position of the hyoid bone was more posterior than it had been preoperatively. Suprahyoidal musculature continuously lengthened from preoperatively to 12 years postoperatively. Total skeletal relapse at B-point and pogonion correlated significantly with postoperative stretch of suprahyoidal musculature. The upper and middle pharyngeal airways were narrower than their preoperative values. CONCLUSIONS: Mandibular changes influence hyoid bone position during the entire postoperative period, whereas stretching of suprahyoidal musculature seems to contribute to skeletal relapse. Mandibular advancement surgery alone possibly does not achieve a stable increase of pharyngeal airway size over a long-term period of 12 years.

Adolescent↗

PubMed2005

An alternative soft tissue analysis following mandibular setback by sagittal split ramus osteotomy.

OBJECTIVE: The objective of this study was to determine alternative ratios of soft-to-hard tissue movement after mandibular setback, taking skeletal relapse and differing patterns of facial divergence into account. STUDY DESIGN: Thirty patients were analyzed cephalometrically over a mean follow-up period of 14 months. RESULTS: The relationship between skeletal and soft tissue movements in the mentolabial folds and at the pogonion was 1:1. Final skeletal relapse was 0.8 mm at the B-point and 0.5 mm at the pogonion. Hence, the alternative ratios were 81% and 68%, respectively. The alternative ratio for the mentolabial sulcus was considerably lower in the low- than in the high- and medium-angle groups of patients. However, there was no statistically significant difference between the patient groups with different facial patterns. CONCLUSION: When the smallness of the measured relapse and the tracing error are taken into account, the difference between the alternative and the conventional ratios was insignificant.

Adolescent↗

PubMed2005

Mandibular setback by sagittal split ramus osteotomy: a 12-year follow-up.

Short- and long-term skeletal changes after mandibular setback were analyzed using bilateral sagittal split ramus osteotomy. Twelve patients who had undergone mandibular setback surgery between 1986 and 1990 were available for long-term cephalography on average 12 years after primary surgery. The mean amount of surgical setback had been 6.4 mm. After the first postoperative year, there was skeletal relapse of 1 mm at the B-point and pogonion (Pg), amounting to 14% of the initial skeletal setback. In contrast to condylar displacement and proximal segment rotation, osteotomy slippage was associated with positional changes at the B-point and Pg. From 1 to 12 years postoperatively, the B-point and Pg remained stable. Mandibular ramus and corpus length decreased 2.1 mm and 1.3 mm, respectively, indicating remodeling at the osteotomy sites and probably condylar resorption.

Adolescent↗

PubMed2004

Skeletal relapse after mandibular advancement and setback in single-jaw surgery.

PURPOSE: The aim of this study was to identify contributing factors to skeletal relapse by analyzing cephalometric changes after bilateral sagittal split ramus osteotomy. PATIENTS AND METHODS: This study included 60 consecutive patients who underwent either mandibular advancement (30 patients) or setback surgery (30 patients). There were 36 women and 24 men (mean age, 23 years). The radiographs of these patients taken immediately before operation, at 1 week, and 14 months postoperatively were studied. To analyze the influence of hyper- and hypodivergent facial patterns on the surgical outcome, the patients were divided into 3 groups according to the mandibulo-nasal plane angle. The position of the maxilla was also taken into account. RESULTS: Measured at B-point, skeletal relapse was 1.3 mm (30%) after mean advancement of 4.4 mm and 0.8 mm (12%) after setback of 6.0 mm. The magnitude of the surgical movement correlated with skeletal relapse. However, the correlation was not linear. Advancement of greater than 7 mm is associated with an increased tendency to relapse (r=0.52), but setback of more than 12 mm with a decreased tendency (r=-0.95). The retrognathic patients with a high mandibulo-nasal plane angle (hyperdivergence) had 30% higher relapse rate. Patients with hypodivergent facial patterns had less relapse in both advancement and setback surgery. CONCLUSION: Skeletal relapse was affected by magnitude of surgical movement and different facial patterns according to the mandibulo-nasal plane angle; however, influences of both factors were different between mandibular advancement and setback.

Adolescent↗

PubMed2004

Analysis of soft tissue profile changes after mandibular advancement surgery.

The aim of this study was to analyze changes in soft tissue profile after mandibular advancement surgery, with special emphasis on the effect of skeletal relapse and different Class II facial patterns. The cephalometric radiographs of 30 consecutive patients (24 women and 6 men, mean age 23 years) who underwent sagittal split osteotomy were studied. The radiographs were taken immediately before operation, at one week and 14 months postoperatively. To analyze the possible influence of hyper- and hypodivergent facial patterns, the patients were classified into low- (4 patients), medium- (16 patients) and high-angle (10 patients) groups according to the magnitude of the mandibulonasal plane angle. The main movement occurred in the horizontal plane. Soft tissue pogonion and mentolabial fold were found to follow the underlying skeletal structures in a nearly 1:1 ratio. On final follow-up, skeletal relapse of 1.3 mm was measured at B-point and of 1.5 mm at pogonion. Taking the skeletal relapses into account, the ratios of both corresponding soft tissue references (alternative ratios) dropped to 60%. Soft tissue pogonion is the most reliable reference for the planning of mandibular advancement. The ratio of soft tissue movement to final skeletal position at the chin amounts to 60% for a realistic prediction. However, the low-angle group differed from other groups by showing a markedly low soft-to-hard tissue ratio of only 14% at pogonion and a high ratio of 109% at the mentolabial fold. However, these differences in ratios between the groups were statistically not significant.

Adolescent↗