Bone regenerative effect of recombinant human bone morphogenetic protein-2 after cyst enucleation / 대한악안면성형재건외과학회지

BACKGROUND: The aim of this study is to quantitatively evaluate the effect of rhBMP-2 for repair of bone defects after cyst enucleation using the osteogenesis index (OI). METHODS: Under general anesthesia, 10 patients (12 lesions) underwent oral or maxillofacial surgery for cyst enucleation. Postoperatively, 12 lesions were divided into two groups: group A (six lesions) was treated with absorbable collagen sponge (ACS) in combination with rhBMP-2, and group B (six lesions) was treated with ACS alone. After 3 months, cone-beam computed tomographic scans were obtained to measure changes in the volume of the lesions. We then calculated the OI of each group at two different Hounsfield units to determine any statistically significant difference between these two groups (Mann–Whitney U test). RESULTS: As tested at the level of new bone, the mean OI was 72.37% in group A and 55.08% in group B —a statistically significant difference (p=0.041). As tested at the level of mature bone, the mean OI was 27.47% in group A and 18.88% in group B, but the difference was not statistically significant (p=0.394). CONCLUSIONS: The application of rhBMP-2 after maxillofacial cyst enucleation accelerated new bone formation in the bone defects. Thus, the use of rhBMP-2 in combination with ACS may be considered an alternative to conventional bone grafting in some patients with postoperative bone defects. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40902-016-0070-4) contains supplementary material, which is available to authorized users.

Retrospective study on change in pharyngeal airway space and hyoid bone position after mandibular setback surgery

OBJECTIVES: The purpose of this study was to evaluate changes in the pharyngeal airway space and hyoid bone position after mandibular setback surgery with bilateral sagittal split ramus osteotomy (BSSRO) and to analyze the correlation between the amount of mandibular setback and the amount of change in pharyngeal airway space or hyoid bone position. MATERIALS AND METHODS: From January 2010 to February 2013, a total of 30 patients who were diagnosed with skeletal class III malocclusion and underwent the same surgery (BSSRO) and fixation method in the Division of Oral and Maxillofacial Surgery, Department of Dentistry at the Ajou University School of Medicine (Suwon, Korea) were included in this study. Lateral cephalograms of the 30 patients were assessed preoperatively (T1), immediately postoperatively (T2), and 6 months postoperatively (T3) to investigate the significance of changes by time and the correlation between the amount of mandibular setback and the amount of change in the airway space and hyoid bone position. RESULTS: Three regions of the nasopharynx, oropharynx, and hypopharynx were measured and only the oropharynx showed a statistically significant decrease (P<0.01). A significant posterior and inferior displacement of the hyoid bone was found 6 months after surgery (P<0.01). Analysis of the correlation between the amount of mandibular setback and the amount of final change in the airway space and hyoid bone position with Pearson's correlation showed no significant correlation. CONCLUSION: In this study, the oropharynx significantly decreased after mandibular setback surgery, and changes in the surrounding structures were identified through posteroinferior movement of the hyoid bone during long-term follow-up. Therefore, postoperative obstructive sleep apnea should be considered in patients who plan to undergo mandibular setback surgery, and necessary modifications to the treatment plan should also be considered.

VERTICAL DIMENSION : A LITERATURE REVIEW / 대한치과보철학회지

This article describes verticsal dimension in its histologic and clinical aspect. Determination of correct vertical dimension of occlusion is one of the most important steps in prosthodontic rehabilitation. It is considered essential for improvement of facial esthetics and stomatognatic functions. Many techniques have been sued for measurement of the vertical dimension in dentulous and edentulous patients : pre-extraction record, physiologic rest position, swallowing, phonetics, esthetics, etc. But, there is no universally accepted or completely accurate method. Though a great deal of energy has been spent trying to find the exact position of the mandible, there is an controversial aspect of vetical dimension.